Effect of transforming growth factor beta and basic fibroblast growth factor on steroid-impaired healing intestinal wounds.

A longitudinal intestinal wound model in the pig was used to assess the effect of parenteral steroids (betamethasone 12 mg 50 kg-1 intramuscularly twice daily) on breaking load. Steroid treatment significantly decreased the breaking load of wounds in the ileum and colon in comparison with wounds from saline-treated animals. In a further group of animals receiving steroids, paired longitudinal wounds were constructed. One wound of a pair was treated with a local application of transforming growth factor beta (TGF-beta) (5 micrograms per wound) or basic fibroblast growth factor (5 micrograms per wound) in a collagen suspension. The other wound was treated with a collagen suspension alone. Ileal wounds treated with TGF-beta were significantly stronger than collagen-treated controls at 7 days. The steroid-induced impairment of breaking load in intestinal wounds is partially reversed by a local application of TGF-beta in a collagen suspension at the time of surgery.     

Combination of platelet-derived growth factor-BB and insulin-like growth factor-I is more effective than platelet-derived growth factor-BB alone in stimulating complete healing of full-thickness wounds in "older" diabetic mice

Platelet-derived growth factor and insulin-like growth factor-I have been shown to interact synergistically to enhance repair of skin wounds in normal healing swine. Platelet-derived growth factor alone has shown promise in treating human chronic ulcers. The objective of this study was to compare the wound healing effects of platelet-derived growth factor-BB alone with those of a combination of platelet-derived growth factor-BB and insulin-like growth factor-I in an improved model with the use of "older" animals with diabetes. Older diabetic (db/db) mice (>15 weeks of age) have less elevated insulin levels compared with young db/db mice. The serum insulin levels in the older animals is 1.0 to 2.5 times that of the nondiabetic animals, a similar increase to that which occurs in human patients with type II diabetes. Healing was evaluated in two studies involving a total of 104 animals. Treatment groups included the following: 4.0 microg/cm(2) of platelet-derived growth factor-BB, 40.0 microg/cm(2) of platelet-derived growth factor-BB, 4.0 microg/cm(2) of both platelet-derived growth factor-BB and insulin-like growth factor-I or vehicle. All growth factors were applied topically in a methylcellulose vehicle to full-thickness wounds every other day for 24 days. Efficacy end points were median and mean time to complete healing and rate of wound closure. The median time to complete healing for animals receiving the platelet-derived growth factor-BB/insulin-like growth factor-I combination was 38% and 33% faster (p < 0.001) than animals receiving 4.0 microg/cm(2) and 40.0 microg/cm(2) of platelet-derived growth factor-BB, respectively. The mean time to complete healing for platelet-derived growth factor/insulin-like growth factor-I treated animals was 31% and 29% faster (p < 0.001) than 4.0 microg/cm(2) and 40.0 microg/cm(2) platelet-derived growth factor-BB treated animals, respectively. Wounds treated with 4.0 microg/cm(2) platelet-derived growth factor-BB/insulin-like growth factor-I healed, on average, in 22 days compared with 31 days for 40.0 microg/cm(2) platelet-derived growth factor-BB alone and 38 days for vehicle. Also, platelet-derived growth factor-BB/insulin-like growth factor-I significantly improved the rate of wound closure throughout the duration of the studies compared with either dose of platelet-derived growth factor-BB alone (p < 0.005) or vehicle (p < 0.001). In conclusion, the data show that the combination of platelet-derived growth factor-BB and insulin-like growth factor-I is more effective than platelet-derived growth factor-BB alone at the doses tested or vehicle treatment in stimulating cutaneous wound healing in older, diabetic mice.     

Sequential cytokine therapy for pressure ulcers: clinical and mechanistic response

OBJECTIVE: To compare the healing response of sequential topically applied cytokines to that of each cytokine alone and to a placebo in pressure ulcers, and to evaluate the molecular and cellular responses. SUMMARY BACKGROUND DATA: Because of a deficiency of cytokine growth factors in chronic wounds and the reversal of impaired healing in animal models, pressure ulcer trials have been performed with several exogenously applied growth factors. Because single-factor therapy has not been uniformly successful, combination or sequential cytokine therapy has been proposed. Laboratory data have suggested that sequential treatment with granulocyte-macrophage/colony-stimulating factor (GM-CSF)/basic fibroblast growth factor (bFGF) might augment the previously reported effect of bFGF alone. METHODS: A masked, randomized pressure ulcer trial was performed comparing sequential GM-CSF/bFGF therapy with that of each cytokine alone and with placebo during a 35-day period. The primary measure was wound volume decrease over time. Cytokine wound levels and mRNA levels were serially determined. Fibroblast-populated collagen lattices (FPCLs) were constructed from serial fibroblast biopsies. Cellular ultrastructure was evaluated by electron microscopy. Changes in ease of surgical closure and its relative cost were determined. RESULTS: Ulcers treated with cytokines had greater closure than those in placebo-treated patients. Patients treated with bFGF alone did the best, followed by the GM-CSF/bFGF group. Patients treated with GM-CSF or bFGF had higher levels of their respective cytokine after treatment. Patients with the greatest amount of healing showed higher levels of platelet-derived growth factor (PDGF) on day 10 and transforming growth factor beta (TGFbeta1) on day 36. Message for the bFGF gene was upregulated after treatment with exogenous bFGF, suggesting autoinduction of the cytokine. FPCLs did not mimic the wound responses. Ultrastructure of wound biopsies showed response to bFGF. Treatment with any of the cytokines improved the wound by allowing easier wound closure. This was most marked for the bFGF-alone treatment, with a cost savings of $9,000 to $9,200. CONCLUSIONS: Treatment with bFGF resulted in significantly greater healing than the other treatments in this trial. The clinical response appeared to be related to upregulation of the bFGF message and to increased levels of PDGF-AB, bFGF, and TGFbeta1 in the wounds and changes in ultrastructure. The resultant improvements could be correlated with cost savings.     

Topical growth factors and wound contraction in the rat: Part II. Platelet-derived growth factor and wound contraction in normal and steroid-impaired rats

The wound contraction model described in Part I was used to study topically applied, recombinant platelet-derived growth factor (rPDGF-BB) and wound contraction in normal and steroid-impaired rats. Circular wounds 4 cm in size were made on the dorsum of the rats with halothane anesthesia. Five groups of 20 normal rats each were treated with the vehicle alone and four concentrations of rPDGF-BB (0.5, 1.0, 3.0, and 10.0 micrograms/ml). Four groups of 20 steroid-impaired rats each were treated with the vehicle alone and three concentrations of rPDGF-BB (0.5, 1.0, and 3.0 micrograms/ml). The wounds were dressed with 2 x 2 gauze, Adaptic, 4 x 4 gauze, and Tubigrip. The investigators were blinded to the treatments until the completion of the experiment, and the treatments were applied in random order. Dressings were changed every 2 to 3 days for 14 days and the wound areas were determined, expressed as a fraction of the original, and plotted versus time. The areas under the curves and the means of the fraction open each day were compared between groups using Student's t-test. The treatment with 3.0-micrograms/ml rPDGF-BB accelerated the rate of wound contraction in the steroid-impaired animals (p less than 0.05).     

Recombinant basic fibroblast growth factor in red blood cell ghosts accelerates incisional wound healing.

The pharmacological manipulation of wound healing with locally applied growth factors is now a practical possibility. The effect of topical applications of recombinant basic fibroblast growth factor (bFGF) on the strength and cellularity of healing incisional rat skin wounds was investigated. Applications of bFGF in a simple vector (either a collagen suspension or saline) were not associated with any positive effects on wound breaking load at 7 days after injury in comparison with vector-treated control wounds; at the highest dose of 50 micrograms per wound, breaking loads were significantly decreased from a mean(s.e.m.) of 287(22) g/cm2 in controls to 201(23) g/cm2 (P < 0.005). Increasing doses of applied peptide were paralleled by increasing wound cellularity. Delay of bFGF release at the site of application was achieved by encapsulation into red blood cell ghosts. Wounds treated with bFGF in such ghosts were 50 per cent stronger than paired control wounds (388(27) versus 256(28) g/cm2, P < 0.002) 7 days after injury. Treated wounds were significantly more cellular at 4 days than paired control wounds. Topical applications of bFGF applied at the time of injury exert a positive effect on incisional wound strength only when a vector that delays release is used.     

Basic fibroblast growth factor in an artificial dermis promotes apoptosis and inhibits expression of α-smooth muscle actin, leading to reduction of wound contraction

To clarify the mechanisms underlying declines in wound contraction caused by basic fibroblast growth factor (bFGF) and the role of autologous fibroblasts in modulating wound healing, we have examined the expression of alpha-smooth muscle actin (alpha-SMA) and apoptosis in a model of wound healing using collagen sponges with and without bFGF (1 microg) and/or fibroblasts (1 x 10(6) cells/cm(2)) applied to experimentally produced full-thickness skin wounds in rats (n=10 for each group). At 7 days postoperatively, wounds filled with a fibroblast-seeded collagen sponge (fibroblast-seeded group) displayed a greater area of collagen sponge and a smaller area of fibroblasts compared with control wounds filled with collagen sponge alone (control group). Therefore, seeding of fibroblasts in the dermal substitute might retard degradation of the collagen sponge, inhibiting fibroblast infiltration into the substitute. By day 14, wounds filled with bFGF-treated collagen sponge without fibroblast seeding (bFGF group) displayed decreased alpha-SMA expression and significantly increased apoptosis compared with other wounds. Double staining revealed that apoptosis in alpha-SMA-positive fibroblastic cells was significantly increased in the bFGF group, suggesting that bFGF treatment is a potent stimulator of myofibroblast apoptosis. Furthermore, morphometric analysis demonstrated the significant decrease in the level of wound contraction and the degree of mature collagen bundle formation in the bFGF group by day 42. The bFGF group also showed increased bFGF expression in macrophages by day 28. These results suggest that bFGF administration to an artificial dermis promotes apoptosis of alpha-SMA-positive fibroblastic cells and inhibits alpha-SMA expression in the treated wound, thus reducing wound contraction.     

Effects of basic fibroblast growth factor on the healing of partial-thickness donor sites. A prospective, randomized, double-blind trial.

A phase I/II clinical study was performed to evaluate the safety and potential efficacy of topical recombinant human basic fibroblast growth factor on the healing of partial-thickness skin graft donor sites in burned children. Each child served as his or her own control. In a blinded and random fashion, one donor site was sprayed with basic fibroblast growth factor (5 microg/cm(2)) on days 0 to 4 after harvest, whereas the other site was treated with vehicle. Twelve patients were entered in the study but one patient died of sepsis that was unrelated to growth factor treatment. Of the remaining 11 patients, no adverse events related to basic fibroblast growth factor occurred. Serum basic fibroblast growth factor levels were never detected and antibody levels remained unchanged. No differences in the rate of epithelialization or days until complete closure were noted (basic fibroblast growth factor = 12.9 +/- 3.9 days, placebo = 12.2 +/- 5.5 days; mean +/- standard error of the mean). No differences in pain, itching, wound fragility, erythema, scarring, or pigmentation were noted. All of the scars matured within 1 year with good to excellent results. Investigators, patients, or families could not distinguish between the two wounds. Although basic fibroblast growth factor proved safe, no enhancement of donor site healing was seen in this small study. Because the time for donor site healing limits subsequent autograft use in patients with sizeable burns, studies should focus on accelerating healing in patients with larger burns where donor site healing is delayed and reharvest is required.     

Effect of bFGF on the inhibition of contraction caused by bacteria

Bacterial contamination of open wounds significantly inhibits wound contraction required in the healing process. Basic fibroblast growth factor (bFGF) has been shown to overcome contraction inhibition in wound-healing models impaired by diabetes or steroids. This study was designed to determine the effect of bFGF on wound contraction inhibition in an area contaminated with bacterial overgrowth. The topically applied bFGF reversed inhibition to wound contraction that normally occurs with bacterial contamination. This reversal does not appear to be due to increased collagen synthesis since bFGF has been shown to decrease collagen synthesis and the treated wounds showed no increase in breaking strength. The use of bFGF significantly decreased the number of days required for wound healing (P less than 0.01) despite active bacterial invasion and may be of value in the treatment of human contaminated wounds.     

Effects of vascular endothelial growth factor on wound closure rates in the genetically diabetic mouse model

Impaired wound healing is characteristic of diabetic patients. Potential reasons include poor inflammatory response, granulation tissue formation, and abnormal patterns of cytokine release and response. Vascular endothelial growth factor, abnormally regulated during healing in diabetics, is the major factor stimulating angiogenesis during normal wound healing. We tested our hypothesis that topically applied vascular endothelial growth factor would improve wound closure rates in diabetic animals in a full-thickness wound model in genetically diabetic mice (C57 BL/KsJ db/db). Animals received either 1.0 micro g of vascular endothelial growth factor165 or polyethylene glycol alone topically to wounds daily between days 0 and 4 post-wounding. Wound area was measured at days 0, 5, 10, 15, and 21. Data were analyzed using probit analysis and expressed as length-of-time (LT) to 50, 90, and 95% wound closure. Among untreated animals, nondiabetics had an LT50 of 8.5 days (fiducial limits 8.3-8.7), while diabetics had an LT50 of 15.8 days (15.6-16.1). Vascular endothelial growth factor-treated animals had LT50 values of 7.8 (7.6-8.1) and 11.8 days (11.6-12.0) for nondiabetics and diabetics, respectively, representing a 25% improvement in time to 50% closure in treated diabetics. We conclude that topically applied vascular endothelial growth factor improves time to wound closure in the genetically diabetic mouse model.     

A modified collagen gel dressing promotes angiogenesis in a preclinical swine model of chronic ischemic wounds

We recently performed proteomic characterization of a modified collagen gel (MCG) dressing and reported promising effects of the gel in healing full‐thickness excisional wounds. In this work, we test the translational relevance of our aforesaid findings by testing the dressing in a swine model of chronic ischemic wounds recently reported by our laboratory. Full‐thickness excisional wounds were established in the center of bipedicle ischemic skin flaps on the backs of animals. Ischemia was verified by laser Doppler imaging, and MCG was applied to the test group of wounds. Seven days post wounding, macrophage recruitment to the wound was significantly higher in MCG‐treated ischemic wounds. In vitro, MCG up‐regulated expression of Mrc‐1 (a reparative M2 macrophage marker) and induced the expression of anti‐inflammatory cytokine interleukin (IL)‐10 and of fibroblast growth factor‐basic (β‐FGF). An increased expression of CCR2, an M2 macrophage marker, was noted in the macrophages from MCG treated wounds. Furthermore, analyses of wound tissues 7 days post wounding showed up‐regulation of transforming growth factor‐β, vascular endothelial growth factor, von Willebrand's factor, and collagen type I expression in MCG‐treated ischemic wounds. At 21 days post wounding, MCG‐treated ischemic wounds displayed higher abundance of proliferating endothelial cells that formed mature vascular structures and increased blood flow to the wound. Fibroblast count was markedly higher in MCG‐treated ischemic wound‐edge tissue. In addition, MCG‐treated wound‐edge tissues displayed higher abundance of mature collagen with increased collagen type I : III deposition. Taken together, MCG helped mount a more robust inflammatory response that resolved in a timely manner, followed by an enhanced proliferative phase, angiogenic outcome, and postwound tissue remodeling. Findings of the current study warrant clinical testing of MCG in a setting of ischemic chronic wounds.     

Acceleration of cutaneous wound healing by brassinosteroids

Brassinosteroids are plant growth hormones involved in cell growth, division, and differentiation. Their effects in animals are largely unknown, although recent studies showed that the anabolic properties of brassinosteroids are possibly mediated through the phosphoinositide 3‐kinase/protein kinase B signaling pathway. Here, we examined biological activity of homobrassinolide (HB) and its synthetic analogues in in vitro proliferation and migration assays in murine fibroblast and primary keratinocyte cell culture. HB stimulated fibroblast proliferation and migration and weakly induced keratinocyte proliferation in vitro. The effects of topical HB administration on progression of wound closure were further tested in the mouse model of cutaneous wound healing. C57BL/6J mice were given a full‐thickness dermal wound, and the rate of wound closure was assessed daily for 10 days, with adenosine receptor agonist CGS‐21680 as a positive control. Topical application of brassinosteroid significantly reduced wound size and accelerated wound healing in treated animals. mRNA levels of transforming growth factor beta and intercellular adhesion molecule 1 were significantly lower, while tumor necrosis factor alpha was nearly suppressed in the wounds from treated mice. Our data suggest that topical application of brassinosteroids accelerates wound healing by positively modulating inflammatory and reepithelialization phases of the wound repair process, in part by enhancing Akt signaling in the skin at the edges of the wound and enhancing migration of fibroblasts in the wounded area. Targeting this signaling pathway with brassinosteroids may represent a promising approach to the therapy of delayed wound healing.     

Effect of cytokine growth factors on the prevention of acute wound failure

Cytokine growth factor treatment of chronic wounds has met with mixed results. The chronic wound presents a hostile environment to peptides such as growth factors. Cytokine growth factors have not been studied extensively in acute wounds. However, incisional hernias are a major example of acute wound failure that has not been solved by various mechanical approaches. A biological approach to acute wound failure by use of cytokine growth factors may offer a new strategy. A rodent incisional hernia model was used. Seventy‐six rats underwent 3‐cm midline celiotomies and were closed with fine, fast‐absorbing sutures to induce intentional acute wound failure. Group 1 received no other treatment. The midline fascia in Groups 2–10 was infiltrated with 100 µl of vehicle alone or vehicle containing various test cytokine growth factors. Necropsy was performed on postoperative day 28 and the wounds were examined for herniation. Incisional hernias developed in 83 percent (13/16) of untreated incisional and 88 percent (7/8) and 83 percent (5/6) of the two vehicle‐treated incisions (PBS and carboxymethylcellulose). Hernia incidences were decreased by priming of the fascial incision with transforming growth factor‐β₂ (12%, 1/8), basic fibroblast growth factor (25%, 2/8) and interleukin‐1β (50%, 3/6) (p < 0.05). Aqueous platelet‐derived growth factor, becaplermin, insulin‐like growth factor, and granulocyte macrophage‐colony stimulating factor did not significantly decrease the incidence of acute wound failure (p > 0.05). A biological approach to acute wound failure as measured by incisional hernia formation can be useful in reducing the incidence of this complication. Transforming growth factor‐β₂, basic fibroblast growth factor, and interleukin 1β all eliminated or significantly reduced the development of incisional hernias in the rat model.     

RGTA OTR 4120, a heparan sulfate proteoglycan mimetic, increases wound breaking strength and vasodilatory capability in healing rat full-thickness excisional wounds

ReGeneraTing Agents (RGTAs), a family of polymers engineered to protect and stabilize heparin‐binding growth factors, have been shown to promote tissue repair and regeneration. In this study, the effects of one of these polymers, RGTA OTR4120, on healing of full‐thickness excisional wounds in rats were investigated. Two 1.5 cm diameter circular full‐thickness excisional wounds were created on the dorsum of a rat. After creation of the wounds, RGTA OTR4120 was applied. The progress of healing was assessed quantitatively by evaluating the wound closure rate, vasodilatory capability, and wound breaking strength. The results showed a triple increase of the local vascular response to heat provocation in the RGTA OTR4120‐treated wounds as compared with vehicle‐treated wounds. On days 14 and 79 after surgery, the wounds treated with RGTA OTR4120 gained skin strength 12% and 48% of the unwounded skin, respectively, and displayed a significantly increased gain in skin strength when compared with control animals. These results raise the possibility of efficacy of RGTA OTR4120 in accelerating surgically cutaneous wound healing by enhancing the wound breaking strength and improving the microcirculation.     

Reversal of the wound healing deficit in diabetic rats by combined basic fibroblast growth factor and transforming growth factor-β1 therapy

Wound healing is impaired in the diabetic state because of, at least in part, low expression of growth factors. Individual growth factors can partially activate healing, yet the actual wound environment presents a dynamic continuum of multiple cellular signals. Complex interactions among growth factors and target cells can have synergistic effects, and several examples of combinatorial, in vivo activity are evident in the literature. In this study, the implantation of a combination of basic fibroblast growth factor and transforming growth factor-beta in rats induced fivefold to sevenfold increases in granulation tissue formation in comparison with implantation of each growth factor alone. Diabetes was induced in adult, male Sprague-Dawley rats with streptozotocin. Incisional wounds and sponge granulation tissue were produced in separate groups and then treated with an injection of 2 microg transforming growth factor-beta1 combined with 10 microg basic fibroblast growth factor on day 3. DNA, collagen, and protein were analyzed in granulation tissue on days 7 and 9, and biomechanical properties of incisions were tested on days 7, 14, and 21. The combination of transforming growth factor-beta1 and basic fibroblast growth factor had marked, positive effects on biochemical parameters of wound healing and reversed the tensile strength deficit of diabetic wounds. Nonradioactive in situ hybridization showed increased expression of messenger RNA for type I and III procollagen and transforming growth factor-beta1 in normal and diabetic wounds, whereas ultrastructural examination showed a marked reorganization of collagen fibrils. These findings reinforce the concept that appropriate mixtures of cytokines rather than individual cytokines may more adequately stimulate tissues in cases of impaired wound healing.     

Wound collagen accumulation in obese hyperglycemic mice

We used C57-BL ob/ob mice as a model to study wound healing in type II (adult-onset) diabetes. Planimetry was used to assess rate of closure in standard open skin wounds. In agreement with previous subcutaneous wound collagen-accumulation studies, closure was slower in the ob/ob mice. Subcutaneous implants were used to evaluate wound collagen accumulation. Weanling mice have collagen accumulation similar to lean littermates (mean 3.43 micrograms/cm vs. 3.46 micrograms/cm), but the same ob/ob animals had decreased wound collagen (mean 2.39 micrograms/cm vs. 3.02 micrograms/cm, P less than 0.04) when mature. Other ob/ob animals fed a restricted diet (and thus not obese) had normal collagen accumulation at the same age. Neither insulin nor diet restriction restored wound collagen accumulation in phenotypically obese mice. Because collagen accumulation is not improved by measures that control hyperglycemia (insulin and diet restriction) and the defect was seen only in phenotypically obese ob/ob mice, the decreased wound collagen accumulation may be due in part to structural changes in adipose tissue.     

Release of basic fibroblast growth factor from a crosslinked glycosaminoglycan hydrogel promotes wound healing

We describe synthetic extracellular matrix (sECM) hydrogel films composed of co-crosslinked thiolated derivatives of chondroitin 6-sulfate (CS) and heparin (HP) for controlled-release delivery of basic fibroblast growth factor (bFGF) to full-thickness wounds in genetically diabetic (db/db) mice. In this model for chronic wound repair, full-thickness wounds were treated with CS, CS-bFGF, or CS-HP-bFGF films. At 2 and 4 weeks postinjury, wound closure and formation of the new epidermis and dermis were determined. Both CS and CS-HP hydrogel films accelerated wound repair, even without bFGF. Addition of bFGF to CS films showed partial dose-dependent acceleration of wound repair. Importantly, addition of bFGF to co-crosslinked CS-HP sECM films showed a dramatic bFGF dose-dependent acceleration of wound healing, as well as improved dermis formation and vascularization. Compared with 27% wound closure in 2 weeks in the controls, 89% wound closure was observed for mice treated with the CS-HP-bFGF films. The synthetic CS-HP sECM films mimic the chemistry and biology of heparan sulfate proteoglycans, and may have clinical potential for topical delivery of growth factors to patients with compromised wound healing.     

碱性成纤维细胞生长因子促进受创皮肤再生的实验研究

成纤维细胞生长因子（ｆｉｂｒｏｂｌｓｔｇｒｏｗｔｈｆａｃｔｏｒ，ＦＧＦ）有促进肉芽，组织生长作用，但对皮肤的修复与再生的作用研究尚少，为此设计了本实验研究。采用大鼠与小型猪背部创伤模型，在无菌条件下用手术刀在动物背部切割皮肤，形成面积约２．５ｃｍ２的圆形创面。分别用碱性成纤维细胞生长因子（ｂａｓｉｃｆｉｂｒｏｂｌａｓｔｇｒｏｗｔｈｆａｃｔｏｒ，ｂＦＧＦ），６０Ｕ／ｃｍ２创面以及相同剂量的生理盐水处理创面，隔天换药一次。结果表明，ｂＦＧＦ具有显著促进上皮细胞生长、加速创面上皮化速率以及增加愈合组织抗张力强度等作用。ｂＦＧＦ显著促进受创皮肤的再生效应可能与它能直接作用于皮肤基底细胞上特异性ｂＦＧＦ受体有关。     

Skin wound closure in athymic mice with cultured human cells, biopolymers, and growth factors

Skin wound closure remains a major problem in acute and reconstructive skin grafting after large burns because of limited availability of donor skin. This report evaluates six protocols for preparation in vitro of skin substitutes composed of cultured human cells, biopolymers, and growth factors for wound closure. Full-thickness wounds in athymic mice treated in a single procedure with cultured skin substitutes were compared directly to treatments with murine skin autograft, human skin xenograft, or no graft. Rectilinear planimetry of healed wounds 6 weeks after surgery showed that skin substitutes cultured in serum-free medium, and for 24 hours before surgery in defined medium with basic fibroblast growth factor (100 ng/ml), were not statistically different (p less than 0.05) in size from treatment with human skin xenograft. Acceptance and persistence of skin substitutes cultured in serum-free media were 70% at 6 weeks after surgery, as determined by staining of healed skin with a fluorescein-labeled monoclonal antibody against human HLA-ABC antigens. Ultrastructural examination of wounds with cultured human skin 6 weeks after treatment showed complete basement membrane, including anchoring fibrils, presence of melanocytes and pigment transfer to keratinocytes, and innervation of healed skin adjacent to basement membrane. These findings demonstrate effectiveness of cultured skin substitutes for closure of skin wounds and illustrate important capabilities to modulate the natural processes of wound repair, to increase supply of materials used for wound repair, and to enhance quality of wound healing.     

表皮细胞生长因子与碱性成纤维细胞生长因子促进创面修复效应的比较性研究

目的 采用小型猪背部创伤模型,定量研究与比较重组人表皮细胞生长因子与重组人碱性成纤维细胞生长因子的促修复效应与作用机制。方法 以创伤模型制作器切割小型猪背部皮肤,造成典型全层皮肤损伤。将１６只小型猪背部的１６０个创面分成两大组,分别以三种不同剂量的ｒｈＥＧＦ（５０,１０及０．５μｇ／创面）和ｒｈＦＧＦ（１５０、９０及３０Ｕ／ｃｍ＾２创面）治疗,每组同时各设溶媒为阴性对照。以伤腔容积与创面愈合面积,     

Topical vascular endothelial growth factor reverses delayed wound healing secondary to angiogenesis inhibitor administration

The prevention of new blood vessel growth is an increasingly attractive strategy to limit tumor growth. However, it remains unclear whether anti-angiogenesis approaches will impair wound healing, a process thought to be angiogenesis dependent. Results of previous studies differ as to whether angiogenesis inhibitors delay wound healing. We evaluated whether endostatin at tumor-inhibiting doses delayed excisional wound closure. C57/BL6J mice were treated with endostatin or phosphate-buffered solution 3 days prior to the creation of two full-thickness wounds on the dorsum. Endostatin was administered daily until wound closure was complete. A third group received endostatin, but also had daily topical vascular endothelial growth factor applied locally to the wound. Wound area was measured daily and the wounds were analyzed for granulation tissue formation, epithelial gap, and wound vascularity. Endostatin-treated mice showed a significant delay in wound healing. Granulation tissue formation and wound vascularity were significantly decreased, but reepithelialization was not effected. Topical vascular endothelial growth factor application to wounds in endostatin-treated mice resulted in increased granulation tissue formation, increased wound vascularity, and wound closure approaching that of control mice. This study shows that the angiogenesis inhibitor endostatin delays wound healing and that topical vascular endothelial growth factor is effective in counteracting this effect.