CA1258630A - Compositions and method for improving wound healing - Google Patents
Compositions and method for improving wound healingInfo
- Publication number
- CA1258630A CA1258630A CA000474650A CA474650A CA1258630A CA 1258630 A CA1258630 A CA 1258630A CA 000474650 A CA000474650 A CA 000474650A CA 474650 A CA474650 A CA 474650A CA 1258630 A CA1258630 A CA 1258630A
- Authority
- CA
- Canada
- Prior art keywords
- collagen
- composition
- suspension
- heparin
- alginate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K38/00—Medicinal preparations containing peptides
- A61K38/16—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
- A61K38/17—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
- A61K38/39—Connective tissue peptides, e.g. collagen, elastin, laminin, fibronectin, vitronectin, cold insoluble globulin [CIG]
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P17/00—Drugs for dermatological disorders
Abstract
Abstract of Disclosure The healing of wounds is promoted by con-tacting the wound surfaces with a suspension of collagen and a glycosaminoglycan that is chemotactic for fibroblasts and/or endothelial cells. Typical glycosaminoglycans that exhibit the desired chemotaxis are heparin, heparan sulfate, and alginate. Two or more glycosaminoglycans can be present in the suspen-sions. Collagen is present in the suspension in the order of 7-10 mg/ml; while the glycosaminoglycan is present in much lower concentrations, e.g, 250-350 µg/ml. Application of the collagen/glycosaminoglycan suspension to open wounds greatly increases the rate of healing.
Description
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ComDositions and Method for ImDrovina ~ound Healinq _ _ _ _ _ Backaround of the Invention l~uman skin is a major organ of the body. It is a complex organization of specialized tissue cells, vascular blood supply networks, nerves, glands, lymphatic system, etc. all of which interact to form the interface between the internal organism and the surrounding environment. In this regard the skin forms a barrier between the body and the environment;
with one of its principal functions being the pro-tection of the body from invasion by potentially hazardous materials and organisms. The skln's integ-rity is therefore all important to the continued well-being of the lndividual, and any breach or rupture represents a threat that must be met by~ the body in order to protect its contained existence.
Breaches or ruptures in the skin's integrity ~ can be caused by external physical forces such as : blows, cuts, missiles etc., that penetrate and disrupt the skin barrier; or by degenerative internal proc-esses occasioned by disease, congenital anomalies or changes in biochemical systems which result in ab-scesses, or ulceration that breach the skin barrier.
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Under normal circumstances the body provides mechanisms for the repair and eventual healing of the ru~ture or breach to thereby restore the integrity of the skin barrier.
The repair process for even minor breaches or ruptures takes a period of time extenaing from hours and days to weeks; and in some instances, as in ulceration, the breach or rupture may persist for extended periods of time, i.e., months or even years.
At all times, whether brief or extended, the potential for invasion by pathogenic organisms or foreign substances continues until new tissue has been gen-erated to fully close the rupture or breach.
Because of the danger of infection, the customary management of wounds includes an initial thorough cleansing of the affected area to remove any contaminants such as dirt, clothing particles, or :
other debris which may introduce pathogenic materials.
Any hopelessly damaged tissues may be debrided and antiseptic materials are applied to make the area as sterile as possible. If considered necessary, sutures may be used to reduce the area of the underlying tissues and thereby limit the amount of tissue exposed to subsequent contamination.
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lZ58630 Or~inarily sterile dressings are applied to the affected area to maintain as clean and sterile an environment as possible. The dressings are period-ically removed to permit the application of antisep-tics and further cleansing of undesirable exudates ifpresent. Further dressings are then applied until the tissue rebuilding mechanisms can begin the healing process.
The healing process is brought about by complex biological mechanisms generally involving several groups of special cells and proteins.
Leucocytes, such as neutrophils and macrophages, crowd the wound site and digest foreign pathogens and debris. Such cells also send out chemical signsls that marshal fibroblasts in the wound vicinity and ultimately generate connective structures, prin-cipally, collagen, which make up a major portion of the new tissues. Endothelial cells generate new blood capillaries that grow into the reconstructed tlssue areas where their presence is necessary to supply nutrients to the newly growing tissue cells and remove catabolic products. As the new capillaries grow, the cells on the margin of the wound simultaneously multiply and grow inwardly. The fibrous tissue arising from this cell growth eventually fills the .. ...
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:, ' :.: ~-~'~S8~3~) ~ 4 --wound cavity with a network of interlacing threads of collagen which in due time, arrange themselves in firm bands and form -the permanent new tissue.
The surface of the wound subsequently is covered by a process of enlargement, flattening, and multiplication of the surface, or epithelial cells at the wounds' edge. These epithelial cells spread as sheets into the wound, beneath the scab. Eventually the proliferating epithelial cell sheets emanating from the wound sides coalesce to cover and close the - wound on the outer surface.
All of the above noted healing processes take considerable time. The rate of healing is influenced by the wound's freedom from infection, the general health of the individual, and presence of retained foreign bodies, or the like.~ For healthy individuals with no complications, the completion of healing nonetheless can take a considerable period of time, i.e., days to weeXs. In some instances, the healing process can be impaired by constitutional deficiences, or by disease processes, and healing may never effectively take place.
Until such time as at least superficial healing has occurred, or if healing is impaired, the individual remains at risk from continued or new ~ :
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infection. Therefore there is a time/rate related risk factor attendant to all wound situations. The quicker the wound can heal, the sooner the risk is removed. Thus any procedure that can influence the rate of wound healing, or even favorably influence the healing of intractible wounds, would be of great value.
Brief Description of the Invention The present invention rela~es to compositions and procedures that improve the ability of wounds to heal and/
or increase the rate at which wounds heal.
According to one aspect of the invention there is provided a method for promoting the healing of a surface wound comprising applying to the wound surface a liquid aqueous suspension of a collagen, wherein said aollagen is not chemically crosslinked, in admixture with a minor amount of a glycosaminoglycan wherein said glycosamino-glycan is chemotactic for fibroblasts or endothelial cells, wherein said liquid aqueous suspension is applied a number of times to the wound surface during the healing process.
According to another aspect of the invention there is provided a composition for use in promoting the healing of wounds comprising a liquid aqueous suspension ; of particles of collagen in admixture with a glycosamino-glycan that exhibits a chemotactic effect on fibroblasts or endothelial cells.
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: - , The present invention presents compositions which, when applied to wounds, greatly enhance and promote the normal healing processes. Such compositions comprise suspensions of a mixture of the fibrous protein, collagen;
and a polysaccharide, glycosaminoglycan~
In the process of the invention, the collagen/
glycosaminoglycan suspension is preferably applied to the wound and maintained in contact therewith for an extended period, iOe., during the entire healing process, or until at least closure o~ the wound by new tissue has taken place.
The application of the collagen/glycosaminogly-can suspension promotes the vascularization of the wound, attrac~s fibroblasts and endothelial cells by chemotaxis, and generally provides a favorable environment for the cells that participate in the healing process.
It is therefore an advantage of the invention, at least in the preferred forms, that it can provide composi-tions that promote the tîssue healing process.
It ~s another advantage of the invention, at least in the preferred forms, that it can provide a method for promoting the healing of skin tissues.
It is yet another advantage of the invention, at least in the preferred forms~ that it can provide collagen/
~ glycosaminoglycan compositions that promote skin tissue healing.
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- 6a -It is still another advantage of the invention, at least in the preferred forms, that it can induce im-proved rates of skin tissue repair by contacting wounds with an aqueous colloidal suspension of collagen and a glycosaminoglycan.
It is yet another advantage of the invention, at least in the preferred forms, that it can induce the healing of previously intractable wounds.
Other objects and advantages of the invention will become apparent from the following detailed descrip-tion and the claims appended hercto.
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Detailed ~escription of the Invention The present invention provides an aqueous dispersion of collagen and a glycosaminoglycan (of a special class as hereinafter defined) for use on wounds to promote the healing thereof. Most usually the aqueous phase is a standard saline solution, i.e., an isotonic salt solution, however water alone may also be used.
As noted, besides the aqueous phase, there are two essential components in the compositions. The first of the essential components is collagen.
Collagen is a proteinaceous material com-prising the major fibrous element of mammalian skin, bone, tendon, cartilage, blood vessels, and teeth.
Its biological purpose is to hold cells together in discrete units; and secondarily it has a directive role in developing tissues. The collagen proteins are distinctive in their physical characteristics in that they form insoluble fibers possessing high tensile strength. It is the fibrous nature of the collagen that serves to hold the various body structures and components together.
While the basic molecular structure of collagen may be modified to meet the needs of particu-lar tissues, all collagens are vrganized into a co on ~
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structure consisting of three polypeptide chains thatform a triple stranded helix. These ~riple stranded helical units, in turn, are formed into a quarter-staggered arra~y of linearly aligned bundles which make up collagen fibers. The collagen fibers are sta-bilized by covalent cross-links.
It has been shown that purified collagen can be utilized medically in reconstructive and cosmetic surgery for the replacement of bony structures or gaps in bony structures, and for filling out tissues where wrinkles have formed. In such usage, collagen is secured from mammalian sources, e.g., calves, whereby extraneous proteinaceous material is removed by various dissolution, precipitation and filtration techniques to leave a pure collagenous product.
Unfortunately this pure natural collagen may induce antigenic response in the host subject. Such response is generated by the end portions of the colla~en fibrils which are not helically bound. Fortunately these end poxtions of collagen can be cleaved there-from by treatment with a proteolytic enzyme, e.g.
pepsin. After digestion with pepsin, the cleaved peptide ends are discarded and only the central collagen bundles (tropocollagen) remain. These central collagen bundles have greatly reduced .; ~ ,, .
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antigenicity and they can be used for the purposes noted above without undue antigenic side effects.
The reduced antigenic, enzyme treated collagen is an article of commerce. It can b~ secured from the Collagen Corporation of Palo Alto, California under the trademarked name "Zyderm.'l Such purified collagen is preferred in the present compositions.
Although reduced antigenic collagen is preferred, non-cleaved collagen that has been isolated from animal sources may also be used. It is only necessary that the collagen be prepared in a sterile condition in an aqueous suspension. Some inclusion of materials commonly associated with the collagen, e.g., polysaccharides, can be tolerated and do not interfere with the benefits of the wound healing compositions.
Other forms of processed collagen are also useful in the compositions.
The second essential component in the present composition is a glycosaminoglycan.
Glycosaminoglycans are polysaccharide materials that, in animals, form the principal component of proteoglycans found in connective tissues.
Proteoglycans consist principally of the glycosaminoglycans with minor amounts of protein.
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: :- . : -Similar molecular structures are also found in plants.
The glycosaminoglycans, being polysaccharides, comprise repeating units of an amino disaccharide. The amino sugar may be a derivative of the aldose sugars, e.g., glucose, galactose in the case of animals, mannose in the case of plants etc. Some common glycosamino-glycans are heparin, heparan sulfate, keratan sulfate, chondroitin sulfate, hyaluronate, in the case of animals;
and alginate, in the case of marine plants.
It should be understood however, that only certain members of the glycosaminoglycans are useful in the wound healing compositions. Specifically, those glycosaminoglycans that exhibit chemotaxis for fibro-blasts or endothelial cells are useful in the present lS invention. Those glycosaminoglycans that exhibit no chemotaxis, or low chemotaxis, for fibroblasts or endothelial cells are not preferred for use in the present compositions.
Chemotaxis can be determined by several means.
Tests can be run in Boyden chambers according to the techniques taught by Boyden in Journal of Experimental Medicine ~ol. 115, p. a53 et. seq. (1962). In the present instance, fibroblasts and/or endothelial cells are placed in the solution in one half of the Boyden chamber, while the glycosaminoglycan of interest is dispersed at low concentrations (e.g. 10 10 gm/ml) in the solution in :
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' lZ5~3~i30 the second half of the chamber. The two halves of the chamber are separated by a semi-permeable membrane.
Migration of the fibroblasts or endothelial cells to and through the semi-permeable membrane is subsequently noted by microscopic examination. Those glycosaminoglycans exhibiting a strong chemotactic effect are suitable for use in the present compositions.
In Table 1 below~ there is presented some data obtained from a series of Boyden chamber tests on collagen as well as a number of glycosaminoglycans~ In the tests the compounds of interest were tested at various concen-trations for their ability to attract fibroblasts. Only the concentration at which the compound exhibited maximumi chemotaxis is shown in the Table.
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~2~;8630 - l2 -Concentration for Fold increase optimal chemotaxis in chemotaxis Compound(gm/ml) over control (1) 5 control (saline) - 1.0 collagen - 1.0 chondroitin -10 sulfatelxlO 2.3 10 Hyaluronic -8 acidlxlO 2.0 AlginatelxlO 8.6 Heparin1 lo~10 3 5 -Thus, in in vltro Boyden chamber tests, heparin and especially alginate exhibit strong chemotaxis for fibroblasts and/or endothelial cells.
In another more pertinent in vivo test ~
technique, a piece of polyvinyl alcohol (PVAj sponge ("Ivalon") is implanted in the dermis of test animals.
Test compositions, i.e. collagen and a glycosaminoglycan or control materials, e.g. collagen alone, are impregnated into various samples of the PVA
sponge prior to implantation. After a period of time, e.g., seven days, the PVA sponge is retrieved from the animal, histologically sectioned and microscopically examined for invasion of cells and the deposition of ,, ~ :
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, l'~S8~30 e~:tracellular matrix in the sponge mass. The extent of fibroblasts and endothetial cell infiltration is a measure of the ability of the composition to promote healing by attràction (chemotaxis) of repair cells into the area.
In one group of experiments using the in vivo test technique outlined above: PVA sponge alone;
PVA sponges impregnated with collagen t8.75 mglml) alone in saline; or collagen (8.75 mg/ml) in com-bination with various glycosaminoglycans (280 ~g/ml) in saline were implanted into test animals. After 7days, the implants were removed and examined micro-scopically to determine the percent of sponge volume that had been invaded by new capillaries. Table 2 below sets forth the results:
Volume % vascularization at 7 days after implant.
PVA sponge alone - 0.67 %
Sponge + collagen alone - 1.20 %
20 Sponge + collagen +
hyaluronic acid - 1.67 %
Sponge + collagen ~
chondroitin sulfate - 2.64 %
Sponge + collagen + alginate - 5.20 %
25 Sponge + collagen + heparln - 6.66 %
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From the above it will be noted that compo-sitions including heparin and alginate exhibited a marked ability to promote vascularization.
Chondroitin sulfate was significantly weaker than either heparin or alginate ; while collagen alone, and collagen with hyaluronic acid appeared to be only weakly active when compared to heparin or alginate.
Thus the useful compositions of the in-vention comprise collagen and a glycosaminoglycan that exhibits chemotaxis for fibroblasts and/or endothelial cells. It will be understood that the glycosamino-glycans can be present in combination in the composi-tions. For instance, heparin whlch exhibits a very strong ability to promote vascularization may be used in admixture with alginate, which exhibits a very strong chemotaxis for fibrob1asts. Comblnations of the various glycosaminoglycans may be selected to emphasize the particular chemotactic properties of the various glycosamlnoglycans. Heparin, heparan sulfate, and alginate are the preferred glycosaminoglycans for use in the present compositions. Hyaluronate and chondroitin sulfate are less useful in the present compositions.
Heparin and heparan sulfate are staple pharmaceutic products, and are commercially obtainable , ',' ':`:,' ' :
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from any number of pharmaceutical sources. Alginates are produced from sea-weeds and are also readily available from pharmaceutical sources. They are most commonly available as the salt form, e.g. sodium alginate. As used herein "alginate" refers to such salt compositions. Although the heparins and alginates are the preferred glycosaminoglycans for use in the healing compositions, it will be understood that other glycosaminoglycans are also useful, so long as they exhibit a good chemotactic effect vis-a-vis fibroblasts and/or endothelial cells.
The concentrations of collagen, and espe-cially the glycosaminoglycan, in the aqueous disper-sion must be controlled in order to achieve the 1~ maximum healing effect. In addition, the relative concentrations of the collagen and glycosaminoglycan components must be maintained within fairly well defined limits. If the collagen concentration is too high, there is an inhibition of the migration of fibroblast cells into the wound area~ The presence of fibroblasts is vital to the ultimate repair of the damaged tissues. Similarly t if the glycosaminoglycan concentration is too high, undesirable local hemor-rhaging or inflammation may occur. But if the glycosaminoglycan concentration is too low, fibroblast ~dl ~ .'. ~ ' , '~
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and endothelial cell migration into the wound is markedly reduced from the migration rates noted at optimum glycosaminoglycan levels.
Thus it has been determined that collagen should be present in the aqueous dispersion at an optimal concentration of about 7-10 mg/ml.; while the glycosaminoglycan~s) should be present at an optimal concentration of about 250-350 ~g/ml. Considerable variation above or below the noted concentrations is permissible. Collagen concentrations can be in the .... _ ~
range of several milligrams/milliliters up to perhaps 15-20 milligrams/milliliter. The glycosaminoglycan(s) - can be in the range of perhaps 100 microe grams/milliliter up to perhaps 1000 micro-I5 grams/milliliter, so long as undue inflammation does not occur.
It is desirable to hold the concentrations close to the stated amounts to produce optimum re-sults, and to avoid inhibitory effects or inflammatory reactions. The preferred concentration for collagen is 8.75 mg/ml, and 280 ~g/ml for the glycosaminoglycan(s). It should be understood, however, that the concentrations may be varied by perhaps one-half to tw1ce the optimal concentrations without critically impairing the usefulness of the .
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wound hea~ing compositions. i~owever, at concen-trations much further below or above the optimal levels, reduced effectiveness and undesireable side-effects can come into play.
The ratio of collagen to glycosaminoglycan is also important to the optimal effectiveness of the compositions. Compositions showing optimal benefit have a collagen concentration some 25-35 times greater than the glycosaminoglycan concentration. Stated in another way, the glycosaminoglycan concentration should be in the vicinity of about 3 to 4% of the collagen concentration for optimal effectiveness. If the collagen concentration in the aqueous phase is in-creased, then the glycosaminoglycan concentration ;~ 15 should also be increased to maintain the desired ~ concentration ratio. While the noted ratios are : :
important to maintain the optimum healing effect, --ratios diverging from those stated may be used, but the healing effect is diminished.
The compositions of the invention are prepared from commercially available dispersions of the individual components. Collagen is normally available as a saline suspension at a concentration of ~ 35 mg/ml. The commercial product is diluted with ! ~
`~25 sterile normal saline to the concentration levels .
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For some purposes it may be desirable to thicken the compositions into a more viscous or semi-solid gelled state. If such is desired, standard medically accept-able gelling materials, e~g. cellulose, may be in-~~~ cluded in the compositions.
The prepared compositions should be main-tained under refrigeration; but should not be frozen or maintained at room temperature. Freezing will interfere with suspension properties. Ambient temper-atures may permit the growth of any minute amount of contaminants. When kept under refrigeration, the suspensions will maintain their effectiveness for extended periods, i.e. months.
Although the compositions may be used as the aqueous colloidal suspension of collagen and glycosaminoglycan, per se, it is also possible to add small amounts of an antibiotic, e.g. neomycin sulfate, ~ normally used for toplcal applications. Such additlon ; 25 of a topical antibiotic is not necessary to promote ~;:
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~ " ' : . ' ' i258630 wound healing by the present compositions. Such addition is solely as a matter of convenience in the general management of wounds. ;
In any event the wound healing compositions are used as follows:
The wound is first thoroughly cleansed and decontaminated as per standard medical practice and any necrotic tissue is debrided to leave as clean and sterile a wound surface as possible. A quantity of the saline-collagén-glycosaminoglycan suspension is applied liberally to all surfaces of the wound and a gauze dressing, thoroughly moistered with the wound healing composition, is placéd over the wound. From time to time, e.g., once or twlce a day, the dresslng is removed and the wound surfaces are cleaned as in standard medical practlce. The wound healing composi~
tion is then reapplied to the wound surfaces, and the wound is covered with new moist gauze dressings as ;~ noted above. This procedure is followed until new epithelial tissue completely closes the wound surface, at which time, application of the wound healing composition is discontinued.
, Observation of Wound Healing Effects As noted previously, wound healing is a :.
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12S8~:i30 c~mplex and involved process with features including gross anatomy, microscopic processes, chemical changes, cell migration etc. The most direct and reliable me~hod of gauging the wound repair process is histological examination. Such examination is, however, only semiquantitive. Nonetheless, histology does give a summation of all the complex processes that take place during wound healing. Therefore it can be used to best assess the benefits derived from any procedures used to improve or hasten healing.
Compositions of collodial suspensions in saline of collagenialone, and collagen with various glycosaminoglycans were applied to wounds. After seven days, a histologic assessment of the wound was made. All compositions had 8.75 mg/ml of collagen.
The glycosaminoglycans were present at concentrations of about 280 ~g/ml.
The following are descriptive composites of the histological assessments:
1. Collagen alone in saline: few fibroblasts; very poor neovascularization; fair degree of inflamma-tion.
ComDositions and Method for ImDrovina ~ound Healinq _ _ _ _ _ Backaround of the Invention l~uman skin is a major organ of the body. It is a complex organization of specialized tissue cells, vascular blood supply networks, nerves, glands, lymphatic system, etc. all of which interact to form the interface between the internal organism and the surrounding environment. In this regard the skin forms a barrier between the body and the environment;
with one of its principal functions being the pro-tection of the body from invasion by potentially hazardous materials and organisms. The skln's integ-rity is therefore all important to the continued well-being of the lndividual, and any breach or rupture represents a threat that must be met by~ the body in order to protect its contained existence.
Breaches or ruptures in the skin's integrity ~ can be caused by external physical forces such as : blows, cuts, missiles etc., that penetrate and disrupt the skin barrier; or by degenerative internal proc-esses occasioned by disease, congenital anomalies or changes in biochemical systems which result in ab-scesses, or ulceration that breach the skin barrier.
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Under normal circumstances the body provides mechanisms for the repair and eventual healing of the ru~ture or breach to thereby restore the integrity of the skin barrier.
The repair process for even minor breaches or ruptures takes a period of time extenaing from hours and days to weeks; and in some instances, as in ulceration, the breach or rupture may persist for extended periods of time, i.e., months or even years.
At all times, whether brief or extended, the potential for invasion by pathogenic organisms or foreign substances continues until new tissue has been gen-erated to fully close the rupture or breach.
Because of the danger of infection, the customary management of wounds includes an initial thorough cleansing of the affected area to remove any contaminants such as dirt, clothing particles, or :
other debris which may introduce pathogenic materials.
Any hopelessly damaged tissues may be debrided and antiseptic materials are applied to make the area as sterile as possible. If considered necessary, sutures may be used to reduce the area of the underlying tissues and thereby limit the amount of tissue exposed to subsequent contamination.
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lZ58630 Or~inarily sterile dressings are applied to the affected area to maintain as clean and sterile an environment as possible. The dressings are period-ically removed to permit the application of antisep-tics and further cleansing of undesirable exudates ifpresent. Further dressings are then applied until the tissue rebuilding mechanisms can begin the healing process.
The healing process is brought about by complex biological mechanisms generally involving several groups of special cells and proteins.
Leucocytes, such as neutrophils and macrophages, crowd the wound site and digest foreign pathogens and debris. Such cells also send out chemical signsls that marshal fibroblasts in the wound vicinity and ultimately generate connective structures, prin-cipally, collagen, which make up a major portion of the new tissues. Endothelial cells generate new blood capillaries that grow into the reconstructed tlssue areas where their presence is necessary to supply nutrients to the newly growing tissue cells and remove catabolic products. As the new capillaries grow, the cells on the margin of the wound simultaneously multiply and grow inwardly. The fibrous tissue arising from this cell growth eventually fills the .. ...
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:, ' :.: ~-~'~S8~3~) ~ 4 --wound cavity with a network of interlacing threads of collagen which in due time, arrange themselves in firm bands and form -the permanent new tissue.
The surface of the wound subsequently is covered by a process of enlargement, flattening, and multiplication of the surface, or epithelial cells at the wounds' edge. These epithelial cells spread as sheets into the wound, beneath the scab. Eventually the proliferating epithelial cell sheets emanating from the wound sides coalesce to cover and close the - wound on the outer surface.
All of the above noted healing processes take considerable time. The rate of healing is influenced by the wound's freedom from infection, the general health of the individual, and presence of retained foreign bodies, or the like.~ For healthy individuals with no complications, the completion of healing nonetheless can take a considerable period of time, i.e., days to weeXs. In some instances, the healing process can be impaired by constitutional deficiences, or by disease processes, and healing may never effectively take place.
Until such time as at least superficial healing has occurred, or if healing is impaired, the individual remains at risk from continued or new ~ :
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infection. Therefore there is a time/rate related risk factor attendant to all wound situations. The quicker the wound can heal, the sooner the risk is removed. Thus any procedure that can influence the rate of wound healing, or even favorably influence the healing of intractible wounds, would be of great value.
Brief Description of the Invention The present invention rela~es to compositions and procedures that improve the ability of wounds to heal and/
or increase the rate at which wounds heal.
According to one aspect of the invention there is provided a method for promoting the healing of a surface wound comprising applying to the wound surface a liquid aqueous suspension of a collagen, wherein said aollagen is not chemically crosslinked, in admixture with a minor amount of a glycosaminoglycan wherein said glycosamino-glycan is chemotactic for fibroblasts or endothelial cells, wherein said liquid aqueous suspension is applied a number of times to the wound surface during the healing process.
According to another aspect of the invention there is provided a composition for use in promoting the healing of wounds comprising a liquid aqueous suspension ; of particles of collagen in admixture with a glycosamino-glycan that exhibits a chemotactic effect on fibroblasts or endothelial cells.
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: - , The present invention presents compositions which, when applied to wounds, greatly enhance and promote the normal healing processes. Such compositions comprise suspensions of a mixture of the fibrous protein, collagen;
and a polysaccharide, glycosaminoglycan~
In the process of the invention, the collagen/
glycosaminoglycan suspension is preferably applied to the wound and maintained in contact therewith for an extended period, iOe., during the entire healing process, or until at least closure o~ the wound by new tissue has taken place.
The application of the collagen/glycosaminogly-can suspension promotes the vascularization of the wound, attrac~s fibroblasts and endothelial cells by chemotaxis, and generally provides a favorable environment for the cells that participate in the healing process.
It is therefore an advantage of the invention, at least in the preferred forms, that it can provide composi-tions that promote the tîssue healing process.
It ~s another advantage of the invention, at least in the preferred forms, that it can provide a method for promoting the healing of skin tissues.
It is yet another advantage of the invention, at least in the preferred forms~ that it can provide collagen/
~ glycosaminoglycan compositions that promote skin tissue healing.
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- 6a -It is still another advantage of the invention, at least in the preferred forms, that it can induce im-proved rates of skin tissue repair by contacting wounds with an aqueous colloidal suspension of collagen and a glycosaminoglycan.
It is yet another advantage of the invention, at least in the preferred forms, that it can induce the healing of previously intractable wounds.
Other objects and advantages of the invention will become apparent from the following detailed descrip-tion and the claims appended hercto.
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Detailed ~escription of the Invention The present invention provides an aqueous dispersion of collagen and a glycosaminoglycan (of a special class as hereinafter defined) for use on wounds to promote the healing thereof. Most usually the aqueous phase is a standard saline solution, i.e., an isotonic salt solution, however water alone may also be used.
As noted, besides the aqueous phase, there are two essential components in the compositions. The first of the essential components is collagen.
Collagen is a proteinaceous material com-prising the major fibrous element of mammalian skin, bone, tendon, cartilage, blood vessels, and teeth.
Its biological purpose is to hold cells together in discrete units; and secondarily it has a directive role in developing tissues. The collagen proteins are distinctive in their physical characteristics in that they form insoluble fibers possessing high tensile strength. It is the fibrous nature of the collagen that serves to hold the various body structures and components together.
While the basic molecular structure of collagen may be modified to meet the needs of particu-lar tissues, all collagens are vrganized into a co on ~
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structure consisting of three polypeptide chains thatform a triple stranded helix. These ~riple stranded helical units, in turn, are formed into a quarter-staggered arra~y of linearly aligned bundles which make up collagen fibers. The collagen fibers are sta-bilized by covalent cross-links.
It has been shown that purified collagen can be utilized medically in reconstructive and cosmetic surgery for the replacement of bony structures or gaps in bony structures, and for filling out tissues where wrinkles have formed. In such usage, collagen is secured from mammalian sources, e.g., calves, whereby extraneous proteinaceous material is removed by various dissolution, precipitation and filtration techniques to leave a pure collagenous product.
Unfortunately this pure natural collagen may induce antigenic response in the host subject. Such response is generated by the end portions of the colla~en fibrils which are not helically bound. Fortunately these end poxtions of collagen can be cleaved there-from by treatment with a proteolytic enzyme, e.g.
pepsin. After digestion with pepsin, the cleaved peptide ends are discarded and only the central collagen bundles (tropocollagen) remain. These central collagen bundles have greatly reduced .; ~ ,, .
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antigenicity and they can be used for the purposes noted above without undue antigenic side effects.
The reduced antigenic, enzyme treated collagen is an article of commerce. It can b~ secured from the Collagen Corporation of Palo Alto, California under the trademarked name "Zyderm.'l Such purified collagen is preferred in the present compositions.
Although reduced antigenic collagen is preferred, non-cleaved collagen that has been isolated from animal sources may also be used. It is only necessary that the collagen be prepared in a sterile condition in an aqueous suspension. Some inclusion of materials commonly associated with the collagen, e.g., polysaccharides, can be tolerated and do not interfere with the benefits of the wound healing compositions.
Other forms of processed collagen are also useful in the compositions.
The second essential component in the present composition is a glycosaminoglycan.
Glycosaminoglycans are polysaccharide materials that, in animals, form the principal component of proteoglycans found in connective tissues.
Proteoglycans consist principally of the glycosaminoglycans with minor amounts of protein.
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: :- . : -Similar molecular structures are also found in plants.
The glycosaminoglycans, being polysaccharides, comprise repeating units of an amino disaccharide. The amino sugar may be a derivative of the aldose sugars, e.g., glucose, galactose in the case of animals, mannose in the case of plants etc. Some common glycosamino-glycans are heparin, heparan sulfate, keratan sulfate, chondroitin sulfate, hyaluronate, in the case of animals;
and alginate, in the case of marine plants.
It should be understood however, that only certain members of the glycosaminoglycans are useful in the wound healing compositions. Specifically, those glycosaminoglycans that exhibit chemotaxis for fibro-blasts or endothelial cells are useful in the present lS invention. Those glycosaminoglycans that exhibit no chemotaxis, or low chemotaxis, for fibroblasts or endothelial cells are not preferred for use in the present compositions.
Chemotaxis can be determined by several means.
Tests can be run in Boyden chambers according to the techniques taught by Boyden in Journal of Experimental Medicine ~ol. 115, p. a53 et. seq. (1962). In the present instance, fibroblasts and/or endothelial cells are placed in the solution in one half of the Boyden chamber, while the glycosaminoglycan of interest is dispersed at low concentrations (e.g. 10 10 gm/ml) in the solution in :
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' lZ5~3~i30 the second half of the chamber. The two halves of the chamber are separated by a semi-permeable membrane.
Migration of the fibroblasts or endothelial cells to and through the semi-permeable membrane is subsequently noted by microscopic examination. Those glycosaminoglycans exhibiting a strong chemotactic effect are suitable for use in the present compositions.
In Table 1 below~ there is presented some data obtained from a series of Boyden chamber tests on collagen as well as a number of glycosaminoglycans~ In the tests the compounds of interest were tested at various concen-trations for their ability to attract fibroblasts. Only the concentration at which the compound exhibited maximumi chemotaxis is shown in the Table.
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~2~;8630 - l2 -Concentration for Fold increase optimal chemotaxis in chemotaxis Compound(gm/ml) over control (1) 5 control (saline) - 1.0 collagen - 1.0 chondroitin -10 sulfatelxlO 2.3 10 Hyaluronic -8 acidlxlO 2.0 AlginatelxlO 8.6 Heparin1 lo~10 3 5 -Thus, in in vltro Boyden chamber tests, heparin and especially alginate exhibit strong chemotaxis for fibroblasts and/or endothelial cells.
In another more pertinent in vivo test ~
technique, a piece of polyvinyl alcohol (PVAj sponge ("Ivalon") is implanted in the dermis of test animals.
Test compositions, i.e. collagen and a glycosaminoglycan or control materials, e.g. collagen alone, are impregnated into various samples of the PVA
sponge prior to implantation. After a period of time, e.g., seven days, the PVA sponge is retrieved from the animal, histologically sectioned and microscopically examined for invasion of cells and the deposition of ,, ~ :
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, l'~S8~30 e~:tracellular matrix in the sponge mass. The extent of fibroblasts and endothetial cell infiltration is a measure of the ability of the composition to promote healing by attràction (chemotaxis) of repair cells into the area.
In one group of experiments using the in vivo test technique outlined above: PVA sponge alone;
PVA sponges impregnated with collagen t8.75 mglml) alone in saline; or collagen (8.75 mg/ml) in com-bination with various glycosaminoglycans (280 ~g/ml) in saline were implanted into test animals. After 7days, the implants were removed and examined micro-scopically to determine the percent of sponge volume that had been invaded by new capillaries. Table 2 below sets forth the results:
Volume % vascularization at 7 days after implant.
PVA sponge alone - 0.67 %
Sponge + collagen alone - 1.20 %
20 Sponge + collagen +
hyaluronic acid - 1.67 %
Sponge + collagen ~
chondroitin sulfate - 2.64 %
Sponge + collagen + alginate - 5.20 %
25 Sponge + collagen + heparln - 6.66 %
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From the above it will be noted that compo-sitions including heparin and alginate exhibited a marked ability to promote vascularization.
Chondroitin sulfate was significantly weaker than either heparin or alginate ; while collagen alone, and collagen with hyaluronic acid appeared to be only weakly active when compared to heparin or alginate.
Thus the useful compositions of the in-vention comprise collagen and a glycosaminoglycan that exhibits chemotaxis for fibroblasts and/or endothelial cells. It will be understood that the glycosamino-glycans can be present in combination in the composi-tions. For instance, heparin whlch exhibits a very strong ability to promote vascularization may be used in admixture with alginate, which exhibits a very strong chemotaxis for fibrob1asts. Comblnations of the various glycosaminoglycans may be selected to emphasize the particular chemotactic properties of the various glycosamlnoglycans. Heparin, heparan sulfate, and alginate are the preferred glycosaminoglycans for use in the present compositions. Hyaluronate and chondroitin sulfate are less useful in the present compositions.
Heparin and heparan sulfate are staple pharmaceutic products, and are commercially obtainable , ',' ':`:,' ' :
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from any number of pharmaceutical sources. Alginates are produced from sea-weeds and are also readily available from pharmaceutical sources. They are most commonly available as the salt form, e.g. sodium alginate. As used herein "alginate" refers to such salt compositions. Although the heparins and alginates are the preferred glycosaminoglycans for use in the healing compositions, it will be understood that other glycosaminoglycans are also useful, so long as they exhibit a good chemotactic effect vis-a-vis fibroblasts and/or endothelial cells.
The concentrations of collagen, and espe-cially the glycosaminoglycan, in the aqueous disper-sion must be controlled in order to achieve the 1~ maximum healing effect. In addition, the relative concentrations of the collagen and glycosaminoglycan components must be maintained within fairly well defined limits. If the collagen concentration is too high, there is an inhibition of the migration of fibroblast cells into the wound area~ The presence of fibroblasts is vital to the ultimate repair of the damaged tissues. Similarly t if the glycosaminoglycan concentration is too high, undesirable local hemor-rhaging or inflammation may occur. But if the glycosaminoglycan concentration is too low, fibroblast ~dl ~ .'. ~ ' , '~
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and endothelial cell migration into the wound is markedly reduced from the migration rates noted at optimum glycosaminoglycan levels.
Thus it has been determined that collagen should be present in the aqueous dispersion at an optimal concentration of about 7-10 mg/ml.; while the glycosaminoglycan~s) should be present at an optimal concentration of about 250-350 ~g/ml. Considerable variation above or below the noted concentrations is permissible. Collagen concentrations can be in the .... _ ~
range of several milligrams/milliliters up to perhaps 15-20 milligrams/milliliter. The glycosaminoglycan(s) - can be in the range of perhaps 100 microe grams/milliliter up to perhaps 1000 micro-I5 grams/milliliter, so long as undue inflammation does not occur.
It is desirable to hold the concentrations close to the stated amounts to produce optimum re-sults, and to avoid inhibitory effects or inflammatory reactions. The preferred concentration for collagen is 8.75 mg/ml, and 280 ~g/ml for the glycosaminoglycan(s). It should be understood, however, that the concentrations may be varied by perhaps one-half to tw1ce the optimal concentrations without critically impairing the usefulness of the .
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wound hea~ing compositions. i~owever, at concen-trations much further below or above the optimal levels, reduced effectiveness and undesireable side-effects can come into play.
The ratio of collagen to glycosaminoglycan is also important to the optimal effectiveness of the compositions. Compositions showing optimal benefit have a collagen concentration some 25-35 times greater than the glycosaminoglycan concentration. Stated in another way, the glycosaminoglycan concentration should be in the vicinity of about 3 to 4% of the collagen concentration for optimal effectiveness. If the collagen concentration in the aqueous phase is in-creased, then the glycosaminoglycan concentration ;~ 15 should also be increased to maintain the desired ~ concentration ratio. While the noted ratios are : :
important to maintain the optimum healing effect, --ratios diverging from those stated may be used, but the healing effect is diminished.
The compositions of the invention are prepared from commercially available dispersions of the individual components. Collagen is normally available as a saline suspension at a concentration of ~ 35 mg/ml. The commercial product is diluted with ! ~
`~25 sterile normal saline to the concentration levels .
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For some purposes it may be desirable to thicken the compositions into a more viscous or semi-solid gelled state. If such is desired, standard medically accept-able gelling materials, e~g. cellulose, may be in-~~~ cluded in the compositions.
The prepared compositions should be main-tained under refrigeration; but should not be frozen or maintained at room temperature. Freezing will interfere with suspension properties. Ambient temper-atures may permit the growth of any minute amount of contaminants. When kept under refrigeration, the suspensions will maintain their effectiveness for extended periods, i.e. months.
Although the compositions may be used as the aqueous colloidal suspension of collagen and glycosaminoglycan, per se, it is also possible to add small amounts of an antibiotic, e.g. neomycin sulfate, ~ normally used for toplcal applications. Such additlon ; 25 of a topical antibiotic is not necessary to promote ~;:
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In any event the wound healing compositions are used as follows:
The wound is first thoroughly cleansed and decontaminated as per standard medical practice and any necrotic tissue is debrided to leave as clean and sterile a wound surface as possible. A quantity of the saline-collagén-glycosaminoglycan suspension is applied liberally to all surfaces of the wound and a gauze dressing, thoroughly moistered with the wound healing composition, is placéd over the wound. From time to time, e.g., once or twlce a day, the dresslng is removed and the wound surfaces are cleaned as in standard medical practlce. The wound healing composi~
tion is then reapplied to the wound surfaces, and the wound is covered with new moist gauze dressings as ;~ noted above. This procedure is followed until new epithelial tissue completely closes the wound surface, at which time, application of the wound healing composition is discontinued.
, Observation of Wound Healing Effects As noted previously, wound healing is a :.
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12S8~:i30 c~mplex and involved process with features including gross anatomy, microscopic processes, chemical changes, cell migration etc. The most direct and reliable me~hod of gauging the wound repair process is histological examination. Such examination is, however, only semiquantitive. Nonetheless, histology does give a summation of all the complex processes that take place during wound healing. Therefore it can be used to best assess the benefits derived from any procedures used to improve or hasten healing.
Compositions of collodial suspensions in saline of collagenialone, and collagen with various glycosaminoglycans were applied to wounds. After seven days, a histologic assessment of the wound was made. All compositions had 8.75 mg/ml of collagen.
The glycosaminoglycans were present at concentrations of about 280 ~g/ml.
The following are descriptive composites of the histological assessments:
1. Collagen alone in saline: few fibroblasts; very poor neovascularization; fair degree of inflamma-tion.
2. Collagen and heparin: virtual absence of inflam-mation; intense fibroplasia; extremely rich , . . - . , : ~ , ' ' :
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l~S8~30 network of new capillaries and venules; the wounds at seven days gave a histologic appearance equivalent to unassisted wound repair at 3-4 weeks; extremely vascularized granulation tissue.
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l~S8~30 network of new capillaries and venules; the wounds at seven days gave a histologic appearance equivalent to unassisted wound repair at 3-4 weeks; extremely vascularized granulation tissue.
3. Collagen and alginate: closely similar histolog-ically to collagen-heparin however somewhat less vascularization then collagen-heparin.
4. Collagen and chondroitin sulfate: much less vascularization then collagen-heparin and collagen-alginate; appreciable inflammation.
5. Collagen and hyaluronate: marked reduction in inflammation and fibroplasia; poor vasculari-zation.
Both collagen-heparin and collagen-alginate preparations aggressively promoted wound healing.
Collagen-chondroitin sulfate and colIagen-hyaluronate preparations had a significantly reduced wound healing activity. Collagen alone had no significant activity.
In view of the excellent results obtained in animal studies, some clinical tests were undertaken with the collagen-heparin preparations. The following accounts relate the results of some of these trials:
.
1. A 42 year old female suffering from scleroderma , ~ had chronic, recurring foot ulcers. Prior :: :
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12S13f~30 - 2~ -therapy had consisted of prolonged (up to six months) bed rest and closure of the ulcer with skin grafts. In the case of a new ulcer a collagen (8.75 mg/ml) and heparin (280 ~l/ml) colloidal suspension was applied daily to the ulcerated area. Well vascularized granulation tissue began to form promptly and the ulcer healed completely within 4 weeks without the need for bedrest.
2. An 85 year old male with peripheral vascular _ insufficiency developed a large and deep ulcer over the Achilles tendon area. Conventional therapy failed to halt the progression of the ulcer and the patient was considered to be a candidate for amputation Treatment with the collagen-hepar~ln composition was oommenced.
After 4 months of daily application o the collagen-heparin suspension, the ulcerated area was completely filled with weIl vascularized granulation tissue and epithelialization had taken place.
~ ~ 3. A 34 year old female with sickle cell disease ;~ suffered from recurring ulcers on her lower ;~ ~ extremities. These ulcers had required bedrest ~25 and skin grafting. Upon recurrance of an ulcer, ....
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~5~3630 treatment with the collayen-heparin suspension was undertaken. ~he ulcer healed within six weeks.
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. : : , 12S~3630 SUPPLEMENTARiY_DISCLOSURE
The compositions of the invention comprises suspensions of particles as described above. These suspensions of particles are either dry powders which are usually intim-ately mixed or optionally are suspended in a liquid, such as water or saline or the like. Thus, in the present invention "suspension" may describe a suspension of solid particles, e.g. collagen/CAG, or a suspension of solid particles in a liquid, e.g. collagen/CAG in solvent, water or saline. A colloidal suspension or colloidal dispersion describes the mixture of tiny particles of solid or liquid in a liquid which are combined in such a manner that the solid never precipitates from the liquid or precipitates very slowly (often over a period of years).
The dry powders can be used to form an article, such as a fabric, bandage, gauze, tape or the like upon which is placed or adhered the suspension of collagen in admixture with particles of a glycosaminoglycon.
Particularly effective for healing wounds is an article produced by attaching the dry powder to the surface of, or within the pores of, an artificial skin membrane made of cross-linked (preferably highly cross-linked) collagen. An artificial membrane of this type may be applied to a wound and, if desired, covered with a fabric, bandage, tape or the like.
The dry composition can be made either by (1) mixing the dry components to provide a uniform composition, or (2) making an aqueous or liquid suspension and removing the water or saline using, for example, a freeze drying technique or lyophilization. The composition is prepared according to the composition limits of collagen/CAG as described herein and mechanically placed on the sur~ace of a solid carrier (e.g. sterile bandage, gauze, tape or the like), sterilized and stored in a sterile condition until :, ::
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12S8~i30 needed. The collagen/CAG sur~ace is then placed in contact with the wound surface. In some cases, body fluids will provide the necessary liquid. Preferably, sterile water or saline is added.
Alternatively, the suspension of particles may be applied directly to a surface wound as a dry powder. The wound surface supplies the body liquid necessary to further suspend the particles in a liquid phase. In addition, it is contemplated to add the dry powder to the surface wound followed by a liquid, such as water or saline.
The dry composition normally consists essentially of a major amount of collagen in admixture with a minor amount of CAG, e.g. a combinaSion of heparin and alginate, prefer-ably wherein the composition is chemotactic for tissue repair cells, and more preferably wherein collagen is present at about 7-10 milligrams per milliliter and the heparin and alginate (CAG) are present in a combined total o~ about 250-350 micrograms per milliliter. As is true o~ the liquid compositions, the dry compositions may also ~0 contain small amounts of a stabilizer, a carrier and other components, such as an antibiotic, e.g. neomycin sulfate, normally used for topical applications.
Collagen which has been heavily chemically crosslinked, usually using between about 1-5% (preferably 5~) of a crosslinking agent, such as glutaraldehyde, produces a tight matrix which is difficult for the fibroblasts or endothelial cells to migrate into thus slowing the healing process. On the other hand, collagen which is lightly chemically crosslinked, usually about 0.01%, preferably 0.05% glutaraldehyde~ produces an oriented matrix which enhances the healing process. In the present invention, a balance must be achieved between the tight matrix and the oriented matrix collagen to product the best healing results. Generally, lightly crosslinked collagen or uncrosslinked collagen are preferred.
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lZS8630 Accounts of additional clinical trials are provided below:
1. A 35 year-old female having sickle cell anemia disease suffers for years from recurring surface ulcers on her legs and feet. The slowly healing ulcers usually require resting in bed, and skin grafting for healing.
Upon recurrance of a foot ulcer, a dry suspension of particles of collagen-heparin (8.75 mg/280 ~1) is applied daily to cover the ulcerated area. The wound surface provides body fluid to produce a solid/liquid mixture. The surface wound is expected to be healed completely within six weeks.
2. A 40 year-old male suffers from a surface burn of the forearm. A dry suspension of particles of collagen (8.75 mg) and heparin (280 micrograms) is applied daily to cover the burn area. In this case l-ml of saline is subsequently added to the suspension of particles. The burn wound is expected to heal completely within 4 weeks.
3. A 45 year-old female suffering from recurring surface ulcers of the upper heel near the AchiIles tendon.
Upon recurrance of the ulcer, treatment is undertaken using a pre-packaged bandage of a suspension of particles of collagen (8.75 mg.~ and heparin (275 micrograms) on one flat surface a 4 x 4 inch square of surgical gauze. In the first two-weeks of daily treatment (replacing the prepackaged bandage) the body fluids of the surface wound provide sufficient liquid.
In the latter two-weeks of treatment, one ml of saline solution is added to the wound and gauze area to provide sufficient contact between the wound and collagen/heparinO The ulcer is expected to be ~ completely healed within 4 weeks.
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Both collagen-heparin and collagen-alginate preparations aggressively promoted wound healing.
Collagen-chondroitin sulfate and colIagen-hyaluronate preparations had a significantly reduced wound healing activity. Collagen alone had no significant activity.
In view of the excellent results obtained in animal studies, some clinical tests were undertaken with the collagen-heparin preparations. The following accounts relate the results of some of these trials:
.
1. A 42 year old female suffering from scleroderma , ~ had chronic, recurring foot ulcers. Prior :: :
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12S13f~30 - 2~ -therapy had consisted of prolonged (up to six months) bed rest and closure of the ulcer with skin grafts. In the case of a new ulcer a collagen (8.75 mg/ml) and heparin (280 ~l/ml) colloidal suspension was applied daily to the ulcerated area. Well vascularized granulation tissue began to form promptly and the ulcer healed completely within 4 weeks without the need for bedrest.
2. An 85 year old male with peripheral vascular _ insufficiency developed a large and deep ulcer over the Achilles tendon area. Conventional therapy failed to halt the progression of the ulcer and the patient was considered to be a candidate for amputation Treatment with the collagen-hepar~ln composition was oommenced.
After 4 months of daily application o the collagen-heparin suspension, the ulcerated area was completely filled with weIl vascularized granulation tissue and epithelialization had taken place.
~ ~ 3. A 34 year old female with sickle cell disease ;~ suffered from recurring ulcers on her lower ;~ ~ extremities. These ulcers had required bedrest ~25 and skin grafting. Upon recurrance of an ulcer, ....
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~5~3630 treatment with the collayen-heparin suspension was undertaken. ~he ulcer healed within six weeks.
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. : : , 12S~3630 SUPPLEMENTARiY_DISCLOSURE
The compositions of the invention comprises suspensions of particles as described above. These suspensions of particles are either dry powders which are usually intim-ately mixed or optionally are suspended in a liquid, such as water or saline or the like. Thus, in the present invention "suspension" may describe a suspension of solid particles, e.g. collagen/CAG, or a suspension of solid particles in a liquid, e.g. collagen/CAG in solvent, water or saline. A colloidal suspension or colloidal dispersion describes the mixture of tiny particles of solid or liquid in a liquid which are combined in such a manner that the solid never precipitates from the liquid or precipitates very slowly (often over a period of years).
The dry powders can be used to form an article, such as a fabric, bandage, gauze, tape or the like upon which is placed or adhered the suspension of collagen in admixture with particles of a glycosaminoglycon.
Particularly effective for healing wounds is an article produced by attaching the dry powder to the surface of, or within the pores of, an artificial skin membrane made of cross-linked (preferably highly cross-linked) collagen. An artificial membrane of this type may be applied to a wound and, if desired, covered with a fabric, bandage, tape or the like.
The dry composition can be made either by (1) mixing the dry components to provide a uniform composition, or (2) making an aqueous or liquid suspension and removing the water or saline using, for example, a freeze drying technique or lyophilization. The composition is prepared according to the composition limits of collagen/CAG as described herein and mechanically placed on the sur~ace of a solid carrier (e.g. sterile bandage, gauze, tape or the like), sterilized and stored in a sterile condition until :, ::
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12S8~i30 needed. The collagen/CAG sur~ace is then placed in contact with the wound surface. In some cases, body fluids will provide the necessary liquid. Preferably, sterile water or saline is added.
Alternatively, the suspension of particles may be applied directly to a surface wound as a dry powder. The wound surface supplies the body liquid necessary to further suspend the particles in a liquid phase. In addition, it is contemplated to add the dry powder to the surface wound followed by a liquid, such as water or saline.
The dry composition normally consists essentially of a major amount of collagen in admixture with a minor amount of CAG, e.g. a combinaSion of heparin and alginate, prefer-ably wherein the composition is chemotactic for tissue repair cells, and more preferably wherein collagen is present at about 7-10 milligrams per milliliter and the heparin and alginate (CAG) are present in a combined total o~ about 250-350 micrograms per milliliter. As is true o~ the liquid compositions, the dry compositions may also ~0 contain small amounts of a stabilizer, a carrier and other components, such as an antibiotic, e.g. neomycin sulfate, normally used for topical applications.
Collagen which has been heavily chemically crosslinked, usually using between about 1-5% (preferably 5~) of a crosslinking agent, such as glutaraldehyde, produces a tight matrix which is difficult for the fibroblasts or endothelial cells to migrate into thus slowing the healing process. On the other hand, collagen which is lightly chemically crosslinked, usually about 0.01%, preferably 0.05% glutaraldehyde~ produces an oriented matrix which enhances the healing process. In the present invention, a balance must be achieved between the tight matrix and the oriented matrix collagen to product the best healing results. Generally, lightly crosslinked collagen or uncrosslinked collagen are preferred.
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lZS8630 Accounts of additional clinical trials are provided below:
1. A 35 year-old female having sickle cell anemia disease suffers for years from recurring surface ulcers on her legs and feet. The slowly healing ulcers usually require resting in bed, and skin grafting for healing.
Upon recurrance of a foot ulcer, a dry suspension of particles of collagen-heparin (8.75 mg/280 ~1) is applied daily to cover the ulcerated area. The wound surface provides body fluid to produce a solid/liquid mixture. The surface wound is expected to be healed completely within six weeks.
2. A 40 year-old male suffers from a surface burn of the forearm. A dry suspension of particles of collagen (8.75 mg) and heparin (280 micrograms) is applied daily to cover the burn area. In this case l-ml of saline is subsequently added to the suspension of particles. The burn wound is expected to heal completely within 4 weeks.
3. A 45 year-old female suffering from recurring surface ulcers of the upper heel near the AchiIles tendon.
Upon recurrance of the ulcer, treatment is undertaken using a pre-packaged bandage of a suspension of particles of collagen (8.75 mg.~ and heparin (275 micrograms) on one flat surface a 4 x 4 inch square of surgical gauze. In the first two-weeks of daily treatment (replacing the prepackaged bandage) the body fluids of the surface wound provide sufficient liquid.
In the latter two-weeks of treatment, one ml of saline solution is added to the wound and gauze area to provide sufficient contact between the wound and collagen/heparinO The ulcer is expected to be ~ completely healed within 4 weeks.
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Claims (29)
1. A composition for use in promoting the healing of wounds comprising a liquid aqueous suspension of particles of collagen in admixture with a glycosaminoglycan that ex-hibits a chemotactic effect on fibroblasts or endothelial cells.
2. The composition of claim 1 wherein two or more glycosaminoglycans are present in the suspension.
3. The composition of claim 1 wherein normal saline solution is the suspending component.
4. The composition of claim 1 wherein the aqueous suspension is gelled.
5. The composition of claim 1 wherein collagen is present in the suspension at a concentration of about 7 to 10 milligrams per milliliter.
6. The composition of claim 1 wherein the glycos-aminoglycan is present in the suspension at a concentration of from about 100 to about 1000 micrograms per milliliter.
7. The composition of claim 1 wherein the glycos-aminoglycan is present in the suspension at a concentra-tion of about several hundred micrograms per milliliter.
8. The composition of claim 1 wherein the ratio of the concentration of collagen to the concentration of glycosaminoglycan is about 25-35 to 1.
9, The composition of claim 8 wherein the glycos-aminoglycan is heparin.
10. The composition of claim 8 wherein the glycos-aminoglycan is heparan sulfate.
11. The composition of claim 8 wherein the glycos-aminoglycan is an alginate.
12. The composition of claim 2 wherein heparin and alginate are admixed together in the suspension.
13. A composition comprising a major amount of colla-gen in particle form in admixture with a minor amount of heparin, and sufficient water or saline to suspend the collagen and the heparin.
14. The composition of claim 13 wherein the composi-tion is chemotactic for fibroblasts or endothelial cells.
15. The composition of claim 13 wherein collagen is present at about 7-10 milligrams per milliliter and hepa-rin is present at about 250-350 micrograms per milliliter.
16. A composition comprising a major amount of colla-gen in particle form in admixture with a minor amount of an alginate, and sufficient water or saline to suspend the collagen and alginate.
17. The composition of claim 16 wherein the composi-tion is chemotactic for fibroblasts or endothelial cells.
18. The composition of claim 16 wherein collagen is present at about 7-10 milligrams per milliliter and the alginate is present at about 250-350 micrograms per milliliter.
19. A composition comprising a major amount of col-lagen in particle form in admixture with a minor amount of a combination of heparin and alginate, and sufficient water or saline to suspend the collagen, heparin and alginate.
20. The composition of claim 19 wherein the composi-tion is chemotactic for fibroblasts or endothelial cells.
21. The composition of claim 19 wherein collagen is present at about 7-10 milligrams per milliliter and the heparin and alginate are present in a combined total of about 250-350 micrograms per milliliter.
22. An article of manufacture for promoting the healing of a surface wound, which article comprises, a substantially dry suspension of particles of collagen in admixture with a minor amount of a glycosaminoglycan which is chemotactic for fibroblasts and endothelial cells, wherein said suspension of particles is located on the surface of a suitable carrier selected from a fabric, gauze or tape.
23. The article of Claim 22 wherein two or more glycos-aminoglycan are combined in the suspension of particles.
24. The article of Claim 22 wherein the glycosamino-glycan is heparin.
CLAIMS SUPPORTED BY THE SUPPLEMENTARY DISCLOSURE
CLAIMS SUPPORTED BY THE SUPPLEMENTARY DISCLOSURE
25. A composition for use in promoting the healing of a surface wound, comprising a dry suspension of particles of collagen in admixture with particles of glycosaminoglycan that exhibits a chemotactic effect on fibroblasts and endothelial cells.
26. A composition according to Claim 25 comprising a major amount of collagen in particle form in admixture with a minor amount of heparin in particle form.
27. A composition according to Claim 25 comprising a major amount of collagen in particle form in admixture with a minor amount of an alginate in particle form.
28. A composition according to Claim 25 comprising a major amount of collagen in particle form in admixture with a minor amount of a combination of heparin in particle form and alginate in particle form.
29. An article of manufacture for promoting the healing of a surface wound, which article comprises a substantially dry suspension of particles of collagen in admixture with a minor amount of a glycosaminoglycan which is chemotactic for fibroblasts and endothelial cells, wherein said suspension of particles is located on the surface of, or within pores of, an artificial skin membrane.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US583,159 | 1984-02-24 | ||
| US06/583,159 US4745098A (en) | 1984-02-24 | 1984-02-24 | Compositions and method for improving wound healing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1258630A true CA1258630A (en) | 1989-08-22 |
Family
ID=24331918
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000474650A Expired CA1258630A (en) | 1984-02-24 | 1985-02-19 | Compositions and method for improving wound healing |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4745098A (en) |
| EP (1) | EP0154447B1 (en) |
| JP (1) | JPH0751512B2 (en) |
| AT (1) | ATE58839T1 (en) |
| CA (1) | CA1258630A (en) |
| DE (1) | DE3580769D1 (en) |
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| US4760131A (en) * | 1986-04-23 | 1988-07-26 | Collagen Corporation | Wound-healing composition |
| CA1294546C (en) * | 1986-04-23 | 1992-01-21 | John S. Sundsmo | Wound healing composition containing collagen |
| US4840626A (en) * | 1986-09-29 | 1989-06-20 | Johnson & Johnson Patient Care, Inc. | Heparin-containing adhesion prevention barrier and process |
| AR243204A1 (en) * | 1986-11-21 | 1993-07-30 | Ajorca Sa | A method for the chemical depolymerisation of polysaccharides. |
| JPS63229068A (en) * | 1987-03-17 | 1988-09-22 | 新技術事業団 | Electric stimulation wound treatment apparatus |
| US5037810A (en) * | 1987-03-17 | 1991-08-06 | Saliba Jr Michael J | Medical application for heparin and related molecules |
| US5273900A (en) * | 1987-04-28 | 1993-12-28 | The Regents Of The University Of California | Method and apparatus for preparing composite skin replacement |
| WO1989000043A1 (en) * | 1987-07-08 | 1989-01-12 | Martin Kludas | Ophthalmic agent and related compositions and method for treatment of the cornea |
| US5036056A (en) * | 1987-07-08 | 1991-07-30 | Martin Kludas | Methods for treating damaged corneal, uterine, or cartilage tissue |
| US5055298A (en) * | 1987-12-01 | 1991-10-08 | Chemisches Laboratorium Dr. Kurt Richter Gmbh | Cosmetic composition comprising an extracellular connective tissue matrix |
| US4945086A (en) * | 1988-05-03 | 1990-07-31 | The Board Of Trustees Of The Leland Stanford Junior University | Smooth muscle cell growth inhibitor |
| US5219576A (en) * | 1988-06-30 | 1993-06-15 | Collagen Corporation | Collagen wound healing matrices and process for their production |
| US4950483A (en) * | 1988-06-30 | 1990-08-21 | Collagen Corporation | Collagen wound healing matrices and process for their production |
| US5175147A (en) * | 1988-08-19 | 1992-12-29 | Takeda Chemical Industries, Ltd | Acid-resistant fgf composition and method of treating ulcerating diseases of the gastrointestinal tract |
| JP2807741B2 (en) * | 1988-12-22 | 1998-10-08 | コレチカ | Method for stabilizing liposome, stabilized liposome composition, and pharmaceutical and cosmetic compositions containing the same |
| ATE98656T1 (en) * | 1989-10-04 | 1994-01-15 | Akzo Nv | SULPHATED GLYCOSAMINOGLYCURONANS WITH ANTITHROMBOTIC ACTIVITY. |
| AU6872691A (en) * | 1989-10-27 | 1991-05-31 | Case Western Reserve University | Inhibition of cell growth by keratan sulfate, chondroitin sulfate, dermatan sulfate and other glycans |
| BR9106377A (en) * | 1990-04-26 | 1993-04-27 | Cytrx Corp | COMPOSITION AND PROCESS FOR TOPICAL TREATMENT OF INJURED OR NURSING TISSUE |
| US5500409A (en) * | 1990-10-01 | 1996-03-19 | Thomas Jefferson University | Method for inhibiting collagen synthesis by keloid fibroblasts |
| SE9101155D0 (en) * | 1991-04-18 | 1991-04-18 | Kabi Pharmacia Ab | NOVEL HEPARIN DERIVATIVES |
| US5705178A (en) * | 1991-05-31 | 1998-01-06 | Gliatech, Inc. | Methods and compositions based on inhibition of cell invasion and fibrosis by anionic polymers |
| US5605938A (en) * | 1991-05-31 | 1997-02-25 | Gliatech, Inc. | Methods and compositions for inhibition of cell invasion and fibrosis using dextran sulfate |
| JP2855307B2 (en) * | 1992-02-05 | 1999-02-10 | 生化学工業株式会社 | Photoreactive glycosaminoglycans, cross-linked glycosaminoglycans and methods for producing them |
| US5670169A (en) * | 1993-12-20 | 1997-09-23 | E.R. Squibb & Sons, Inc. | Wound hydrating gel with novel preservative system and low cytotoxicity |
| US7883693B2 (en) | 1995-12-18 | 2011-02-08 | Angiodevice International Gmbh | Compositions and systems for forming crosslinked biomaterials and methods of preparation of use |
| WO1997022371A1 (en) | 1995-12-18 | 1997-06-26 | Collagen Corporation | Crosslinked polymer compositions and methods for their use |
| US6833408B2 (en) | 1995-12-18 | 2004-12-21 | Cohesion Technologies, Inc. | Methods for tissue repair using adhesive materials |
| US5668119A (en) * | 1996-02-22 | 1997-09-16 | Medenica; Rajko D. | Topical pharmaceutical containing heparin and method of treatment |
| US6451326B2 (en) | 1996-05-02 | 2002-09-17 | Burt D. Ensley | Cosmetic compositions |
| US7691829B2 (en) * | 1998-03-24 | 2010-04-06 | Petito George D | Composition and method for healing tissues |
| WO2002091999A2 (en) * | 2001-05-09 | 2002-11-21 | Geron Corporation | Treatment for wounds |
| JP4712380B2 (en) * | 2002-07-26 | 2011-06-29 | 三笠製薬株式会社 | Topical preparation |
| CN101018812B (en) | 2004-09-15 | 2012-06-13 | 生化学工业株式会社 | Photoreactive polysaccharide, photocrosslinking polysaccharide product, preparation method thereof and medical material prepared from the crosslinking polysaccharide |
| CA2584553A1 (en) * | 2004-09-17 | 2006-03-23 | Cellgentech, Inc. | External agent for treatment of skin ulcer |
| US8303973B2 (en) | 2004-09-17 | 2012-11-06 | Angiotech Pharmaceuticals (Us), Inc. | Multifunctional compounds for forming crosslinked biomaterials and methods of preparation and use |
| WO2012143324A1 (en) | 2011-04-19 | 2012-10-26 | Bioiberica, S.A. | Cartilage product |
| US9782457B2 (en) * | 2011-10-07 | 2017-10-10 | Tissue Repair Company | Flowable formulations for tissue repair and regeneration |
| US9393278B2 (en) | 2013-06-26 | 2016-07-19 | Han Sheng Biotech Co., Ltd. | Method for wound healing |
| CN110038115A (en) * | 2019-04-18 | 2019-07-23 | 北京和生康医疗科技有限公司 | Mineral substance type alkaline compositions and preparation method thereof and purposes |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR6652M (en) * | 1966-12-28 | 1969-01-27 | ||
| US4060081A (en) * | 1975-07-15 | 1977-11-29 | Massachusetts Institute Of Technology | Multilayer membrane useful as synthetic skin |
| GB1515963A (en) * | 1975-07-15 | 1978-06-28 | Massachusetts Inst Technology | Crosslinked collagen-mucopolysaccharide composite materials |
| FR2362632A1 (en) * | 1976-08-23 | 1978-03-24 | Moreau Monique | Compsns. for treatment of cellulitis - contg. glyco-amino-glycan cpd. collagen adenosine mono:phosphate and a phospho di:esterase blocking agent |
| JPS6019725B2 (en) * | 1977-10-04 | 1985-05-17 | ポ−ラ化成工業株式会社 | skin cosmetics |
| US4350629A (en) * | 1981-07-29 | 1982-09-21 | Massachusetts Institute Of Technology | Procedures for preparing composite materials from collagen and glycosaminoglycan |
| US4418691A (en) * | 1981-10-26 | 1983-12-06 | Massachusetts Institute Of Technology | Method of promoting the regeneration of tissue at a wound |
| FR2517315B1 (en) * | 1981-11-30 | 1985-12-20 | Tech Cuir Centre | PROCESS FOR THE PREPARATION OF NEW FORMS OF COLLAGEN, NATIVE OR DERETICULATED, WITH PRESERVED HELICOIDAL STRUCTURE, ASSOCIATED WITH MUCOPOLYSACCHARIDES AND THEIR APPLICATIONS IN PARTICULAR IN THE COSMETOLOGICAL, PHARMACEUTICAL, ANALYTICAL AND OTHER FIELDS |
| US4448718A (en) * | 1983-09-13 | 1984-05-15 | Massachusetts Institute Of Technology | Method for the preparation of collagen-glycosaminoglycan composite materials |
-
1984
- 1984-02-24 US US06/583,159 patent/US4745098A/en not_active Expired - Lifetime
-
1985
- 1985-02-19 CA CA000474650A patent/CA1258630A/en not_active Expired
- 1985-02-20 DE DE8585301127T patent/DE3580769D1/en not_active Expired - Lifetime
- 1985-02-20 EP EP85301127A patent/EP0154447B1/en not_active Expired - Lifetime
- 1985-02-20 AT AT85301127T patent/ATE58839T1/en not_active IP Right Cessation
- 1985-02-23 JP JP60033707A patent/JPH0751512B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US4745098A (en) | 1988-05-17 |
| EP0154447A3 (en) | 1987-08-12 |
| JPS60222425A (en) | 1985-11-07 |
| DE3580769D1 (en) | 1991-01-17 |
| ATE58839T1 (en) | 1990-12-15 |
| JPH0751512B2 (en) | 1995-06-05 |
| EP0154447A2 (en) | 1985-09-11 |
| EP0154447B1 (en) | 1990-12-05 |
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