The safety and effect of topically applied recombinant basic fibroblast growth factor on the healing of chronic pressure sores

New strategies in clinical care of skin wound healing

The prevalence of chronic wounds is closely correlated to the aging population and so-called civilizational diseases. Therefore, they are causing morbidity and mortality of millions of patients worldwide, with an unbroken upward trend. As a consequence, chronic wounds induce enormous and rapidly growing costs for our health care systems and society in general. Thus, medically effective and cost-efficient treatment methods are urgently needed. Methods of 'regenerative medicine' might offer innovative scientific solutions, including the use of stem cells, growth factors and new bioactive materials. These tools are experimentally well described but clinically poorly performed. The main reasons for this are both legislative and economic. This review describes state-of-the-art techniques, up-to-date research projects, innovative preclinical and clinical approaches in wound care, and activities to translate these innovative techniques into clinical routine.

Regeneration of tracheal epithelium using a collagen vitrigel-sponge scaffold containing basic fibroblast growth factor

OBJECTIVES

Our group has had good results in tracheal mucosal regeneration using a collagen vitrigel-sponge scaffold in an animal model. In this study, the effectiveness of this scaffold with the application of basic fibroblast growth factor (b-FGF) was investigated.

METHODS

A collagen vitrigel-sponge scaffold was fabricated with simultaneous addition of b-FGF. Three types of collagen vitrigel-sponge scaffolds were made: no b-FGF, 10 ng of b-FGF, and 100 ng of b-FGF. At 3, 5, 7, and 14 days after implantation in rats, the tracheas were removed and histologically evaluated. The regeneration of mucosal epithelium and the subepithelial layer was evaluated.

RESULTS

Mucosal epithelium, including pseudostratified epithelium and ciliated cells, regenerated earlier in the scaffolds when b-FGF was applied than when b-FGF was not applied. Regeneration of the subepithelial layer, infiltration of inflammatory cells and fibroblasts, and angiogenesis were promoted earlier in the scaffolds with b-FGF application.

CONCLUSIONS

Our technique for tracheal reconstruction using collagen vitrigel-sponge scaffolds with b-FGF application affords a feasible approach for accelerating the regeneration of the intraluminal surface and subepithelial layer of tracheal tissue.

Harnessing growth factors to influence wound healing

Cutaneous wound healing is a dynamic process with the ultimate goal of restoring skin integrity. On injury to the skin, inflammatory cells, endothelial cells, fibroblasts, and keratinocytes undergo changes in gene expression and phenotype, leading to cell proliferation, migration, and differentiation. Cytokines and growth factors play an essential role in initiating and directing the phases of wound healing. These signaling peptides are produced by a variety of cells and lead to a concerted effort to restore the skin barrier function.

Early experiences with stem cells in treating chronic wounds

This review provides a thorough and clear discussion on the outcomes of stem cells in treating chronic wounds. With recent technological developments that now allow isolation and culture of stem cells, researchers are able to perform vigorous studies on somatic or adult stem cells. Human and animal stem cell studies are discussed with a focus on the basic process of stem cells in wound healing and the authors' first-hand clinical experience with stem cells used for chronic wound healing.

Engineering the growth factor microenvironment with fibronectin domains to promote wound and bone tissue healing

Although growth factors naturally exert their morphogenetic influences within the context of the extracellular matrix microenvironment, the interactions among growth factors, their receptors, and other extracellular matrix components are typically ignored in clinical delivery of growth factors. We present an approach for engineering the cellular microenvironment to greatly accentuate the effects of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor-BB (PDGF-BB) for skin repair, and of bone morphogenetic protein-2 (BMP-2) and PDGF-BB for bone repair. A multifunctional recombinant fragment of fibronectin (FN) was engineered to comprise (i) a factor XIIIa substrate fibrin-binding sequence, (ii) the 9th to 10th type III FN repeat (FN III9-10) containing the major integrin-binding domain, and (iii) the 12th to 14th type III FN repeat (FN III12-14), which binds growth factors promiscuously, including VEGF-A165, PDGF-BB, and BMP-2. We show potent synergistic signaling and morphogenesis between α5β1 integrin and the growth factor receptors, but only when FN III9-10 and FN III12-14 are proximally presented in the same polypeptide chain (FN III9-10/12-14). The multifunctional FN III9-10/12-14 greatly enhanced the regenerative effects of the growth factors in vivo in a diabetic mouse model of chronic wounds (primarily through an angiogenic mechanism) and in a rat model of critical-size bone defects (through a mesenchymal stem cell recruitment mechanism) at doses where the growth factors delivered within fibrin only had no significant effects.

Human pilot studies reveal the potential of a vitronectin: growth factor complex as a treatment for chronic wounds

Several different advanced treatments have been used to improve healing in chronic wounds, but none have shown sustained success. The application of topical growth factors (GFs) has displayed some potential, but the varying results, high doses and high costs have limited their widespread adoption. Many treatments have ignored the evidence that wound healing is driven by interactions between extracellular matrix proteins and GFs, not just GFs alone. We report herein that a clinical Good Manufacturing Practice-grade vitronectin:growth factor (cVN:GF) complex is able to stimulate functions relevant to wound repair in vitro, such as enhanced cellular proliferation and migration. Furthermore, we assessed this complex as a topical wound healing agent in a single-arm pilot study using venous leg ulcers, as well as several 'difficult to heal' case studies. The cVN:GF complex was safe and re-epithelialisation was observed in all but 1 of the 30 patients in the pilot study. In addition, the case studies show that this complex may be applied to several ulcer aetiologies, such as venous leg ulcers, diabetic foot ulcers and pressure ulcers. These findings suggest that further evaluation is warranted to determine whether the cVN:GF complex may be an effective topical treatment for chronic wounds.

Topical application of basic fibroblast growth factor reduces esophageal stricture and esophageal neural damage after sodium hydroxide-induced esophagitis in rats

PURPOSE

To investigate the effect of topical application of basic fibroblast growth factor (bFGF) after caustic esophageal injury in rats.

METHODS

Thirty-six male rats were randomly divided into three groups. Corrosive esophageal injury was produced by internal application of 30% sodium hydroxide (NaOH) solution to the distal esophagus. Group A rats were uninjured. Group B rats were injured and untreated. Group C rats were injured and received topical bFGF (10 μg/ml). Surviving rats were killed at 28 days. The survival rate, body weight gain, symptoms and histopathological changes that included tissue damage score, ratio of esophageal luminal area/total esophageal area (LA/TA) and the proportion of a neural marker PGP 9.5-positive area were assessed.

RESULTS

The survival rate and the prevalence of symptoms were not significantly different between Groups B and C. Although the tissue damage score did not differ in Groups B and C, LA/TA was significantly higher in Group C than in Group B. The proportion of the PGP 9.5-positive area was significantly lower in Groups B and C than in Group A; however, it was higher in Group C than in Group B.

CONCLUSION

Topical application of bFGF was effective in preventing stricture after NaOH-induced esophagitis.

The impact of hyperbaric oxygen therapy on serological values of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF)

Background

Hyperbaric oxygen (HBO) therapy is an effective adjunct treatment for ischemic disorders such as chronic infection or chronic wounds. It combines hyperoxic effects with the stimulating potential of post-therapeutic reactive hypoxia. As its crucial effects, stimulation of fibroblast growth, induction of collagen synthesis and the initiation of angiogenesis are discussed. Angiogenesis is a multistage process resulting in the growth of blood vessels. It includes degradation of extracellular matrix, proliferation and migration of different cell populations and finally formation of new vessel structures. This complex chain of procedures is orchestrated by different cytokines and growth factors. Crucial mediators of angiogenesis are basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF); their in-vivo function is still not fully understood.

Methods

Forty-three patients suffering from sudden sensorineural hearing loss or tinnitus were treated with HBO. The therapy included 10 sessions of 90 minutes each, one session a day. Serological levels of bFGF and VEGF were assessed by enzyme-linked immunosorbent assays performed according to the manufacturer's instructions on day 1, 2, 5 and 10 of HBO therapy and were compared to mean values of the control group, related to the patient's age and sex, and their development observed over the ten days of HBO.

Results

There was no sex- or age dependency of bFGF observed in the present study, whereas under HBO our results showed a significant mitigation of the bFGF concentration. In the present data, there was no connection between the VEGF concentration and the patients' ages. Women showed significantly higher levels of VEGF. There was no significant change of VEGF concentration or the VEGF/bFGF ratio during HBO. All scored results varied within the range of standard values as described in the current literature.

Conclusions

A significant effect of HBO on serum concentrations of bFGF and VEGF was not verified in the present study. Additional application of exogenous growth factors in conjunction with HBO was not obviously linked by a coherent cause-and-effect chain as far as wound healing is concerned.

Effects of basic fibroblast growth factor on rat vocal fold fibroblasts

OBJECTIVES

The overarching goal of this line of research is to translate basic fibroblast growth factor (bFGF) treatment for vocal fold scarring into practical clinical use. In a previous canine investigation, we demonstrated that bFGF improves phonation threshold pressure, mucosal wave amplitude, and histologic measures in vocal folds treated after injury. In the present study, we studied the effects of bFGF on gene expression of the extracellular matrix and growth factors in rat vocal fold fibroblasts.

METHODS

Fibroblasts harvested from the vocal folds of 5 rats were treated with 3 concentrations of bFGF (0, 10, and 100 ng/mL). The fibroblasts were collected at 24 hours and 72 hours after bFGF administration. Quantitative polymerase chain reaction was then used to investigate the gene expression of the investigated growth factors and extracellular matrices.

RESULTS

The results revealed significantly down-regulated expression of procollagen I and significantly up-regulated expression of hyaluronic acid synthase (HAS) 2 and fibronectin in fibroblasts treated with bFGF. The administration of bFGF also resulted in the up-regulation of bFGF and hepatocyte growth factor (HGF). No changes in the expression of HAS-1, tropoelastin, or procollagen III were observed between the treatment and control conditions.

CONCLUSIONS

Treatment with bFGF induces the down-regulation of procollagen I and the up-regulation of HAS-2 in vocal fold fibroblast cell cultures. These gene expression alterations to key mediators of the wound healing process may translate into potential benefits in the remediation of vocal fold injury. The up-regulation of HGF, an antifibrotic effector molecule, may demonstrate additional benefits by optimizing the wound healing environment and by accelerating the wound repair cascade. These findings may provide fuel for additional discoveries into the development of growth factor therapy for the treatment of vocal fold scar.

The characterization and optimization of injectable silicone resin particles in conjunction with dermal fibroblasts and growth factors: an in vitro study

Minimally invasive subdermal injection of liquid silicone has been used clinically to augment the soft tissue of the foot to mitigate high pressures that cause diabetic foot ulcers. However, implant migration has been a clinical issue. The objective of this study was to assess the effects of three specific concentrations of silicone resin particles (12 mum average diameter) in conjunction with either platelet-derived growth factor (PDGF-BB) or basic fibroblast growth factor (bFGF) on fibroblast cell proliferation, collagen synthesis, cell morphology, and migration through in vitro assays and a monolayer scratch wound model. PDGF and bFGF enhanced the proliferation of fibroblasts 5.7-fold and fivefold, respectively, while the addition of silicone particles had no significant effect on proliferation. Collagen production was increased approximately twofold with the addition of bFGF and the medium concentration of particles over bFGF without particles and the PDGF groups. The addition of silicone particles had no significant effect on collagen production compared with control groups without particles. Fibroblast migration was enhanced by the addition of both PDGF and bFGF compared to controls, although slower scratch wound closure rates were observed in the presence of particles compared to controls without particles. Cell morphology suggested that particles induced cellular aggregation encircling silicone particles postwounding as well as migration into the wound area. These results suggest that silicone particles in combination with a growth factor might enhance fibroblast aggregation and implant stability, and could promote connective tissue ingrowth and implant encapsulation in the soft tissue of the diabetic foot.

Allogenic platelet gel in the treatment of pressure sores: a pilot study

Although platelet gel is considered one of the most popular tools in the treatment of chronic ulcers, current consensus on its use is not unanimous. A prospective randomised trial was carried out at the Plastic Surgery Unit of the 'Salvatore Maugeri' Foundation Hospital of Pavia (Italy). The study involved 13 patients affected by spinal cord injury with 16 pressure sores over a period of 20 months. The ulcer was considered the experimental unit of the study irrespective of the number of ulcers per patient. Each consecutive ulcer was randomised to be treated either with allogenic platelet gel or with current best practice approach to chronic wounds dressing protocol. At the end of the treatment 15 ulcers out of 16 improved clinically. No statistically significant difference was demonstrated in volume reduction between the two groups, although a statistically significant difference could be demonstrated in the onset time of granulation tissue proliferation as in the wounds treated with platelet gel the healing process was triggered earlier. Our study suggests that platelet gel is mostly effective within the first 2 weeks of treatment while a prolonged treatment does not provide any significant advantage versus the current best practice approach to chronic wounds protocols.

Growth factors as active participants in carcinogenesis: a perspective

Growth factors are low molecular peptides active in the stimulation of cell proliferation and in the regulation of embryonic development and cellular differentiation. Significant progress has been made in developing effective strategies to treat human malignancies with new chemical compounds based on a rationale directed against various components of signaling pathways. Many of these drugs target a growth factor receptor--for instance, in the form of monoclonal antibodies or inhibitors of tyrosine kinases, such as monoclonal antibodies against epidermal growth factor receptors used in treating certain types of breast cancer. Imatinib mesylate [Gleevec]) is an excellent example of mediators of signal transduction, such as tyrosine kinases. Growth factors proper are used to ameliorate various and sometimes fatal side effects of cytotoxic and/or myelosuppressive chemotherapy. Basic characteristics of several growth families are discussed with therapeutic modalities based on growth factor activity or, more often, inhibition of such activity.

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 microl 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-beta(2) (12%, 1/8), basic fibroblast growth factor (25%, 2/8) and interleukin-1 beta (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-beta(2), basic fibroblast growth factor, and interleukin 1 beta all eliminated or significantly reduced the development of incisional hernias in the rat model.

The role of vascular endothelial growth factor in wound healing

BACKGROUND

A chronic wound is tissue with an impaired ability to heal. This is often a consequence of one of the following etiologies: diabetes, venous reflux, arterial insufficiency sickle cell disease, steroids, and/or pressure. Healing requires granulation tissue depending on epithelialization and angiogenesis. Currently no growth factor is available to treat patients with impaired healing that stimulates both epithelialization and angiogenesis. The objective is to review is the multiple mechanisms of vascular endothelial growth factor (VEGF) in wound healing.

MATERIALS AND METHODS

The authors reviewed the literature on the structure and function of VEGF, including its use for therapeutic angiogenesis. Particular attention is given to the specific role of VEGF in the angiogenesis cascade, its relationship to other growth factors and cells in a healing wound.

RESULTS

VEGF is released by a variety of cells and stimulates multiple components of the angiogenic cascade. It is up-regulated during the early days of healing, when capillary growth is maximal. Studies have shown the efficacy of VEGF in peripheral and cardiac ischemic vascular disease with minimal adverse effects. Experimental data supports the hypothesis that VEGF stimulates epithelialization and collagen deposition in a wound.

CONCLUSION

VEGF stimulates wound healing through angiogenesis, but likely promotes collagen deposition and epithelialization as well. Further study of the molecule by utilizing the protein itself, or novel forms of delivery such as gene therapy, will increase its therapeutic possibilities to accelerate closure of a chronic wound.

Letters

Pressure ulcers are complex chronic wounds for which no gold standard treatment has yet been established, although guidelines have been developed. At present, treatment involves assessment, reduction of pressure, friction and shear forces, optimising local wound care, debridement of necrotic tissue, managing bacterial contamination and correcting nutritional deficits.1 In addition, electrical stimulation, ultraviolet irradiation and local ointments including silver sulphadiazine, neomycin, polymixin and phenytoin have been applied, with varying results.

[Vacuum-assisted closure therapy. Current status and basic research]

The gap between the broad clinical use of vacuum-assisted closure therapy (VT) and knowledge of the physiological mechanisms leading to its effectiveness is great. The value of the technique and its future development are dependent on research into these mechanisms. A meta-analysis evaluating the results of basic research on the effectiveness of VT was carried out based on peer reviewed publications. This is considered in relation to other therapeutic approaches of basic research to wound healing (growth factors etc.). Our study includes a concise description of the scientific background to the mechanisms of cell stimulation using basic work on tissue expansion, bone, vessel and nerve distraction as well as in vitro cell stimulation. Evaluation of the scientific data on all known effects of VT was made based on the results from experimental animal studies, the results of randomized clinical studies, observations on clinical applications and case reports. Assessment of the studies was based on design and significance as well as the appraisal of our own clinical experience. Data involving cellular effects (proliferation, synthesis, wound healing), systemic effects (mediators, systemic inflammatory disease), extracellular effects (perfusion, edema, local wound environment, stabilization, barriers) and complex effects of VT (inflammation, matrix function, blood supply) were examined. Systematic analysis of the data allows scientifically interested surgeons rapid access to the theme, the first, to this extent, extensive overview of the current scientific situation as well as a comprehensive bibliography for all areas involving the theme of mechanical cell stimulation. The authors list major areas for future research and encourage the development of multicenter studies.

Vitronectin: growth factor complexes hold potential as a wound therapy approach

Topical administration of growth factors has displayed some potential in wound healing, but variable efficacy, high doses, and costs have hampered their implementation. Moreover, this approach ignores the fact that wound repair is driven by interactions between multiple growth factors and extracellular matrix (ECM) proteins. We report herein that complexes comprising IGF and IGF-binding proteins bound to the ECM protein vitronectin (VN) significantly enhance cellular functions relevant to wound repair in human skin keratinocytes in two- and three-dimensional in vitro cell models and are active, even in the presence of wound fluid. Moreover, these responses require activation of both the IGF receptor and the VN-binding alpha(v) integrins. Further, we assessed the complexes as a topical agent in the treatment of deep dermal partial thickness burns in a porcine model. This pilot study revealed that the complexes may hold promise as a wound healing therapy. Critically, the significant responses observed in vitro and the encouraging preliminary data in vivo were obtained with nanogram doses of growth factors. This suggests that coupling delivery of growth factors to ECM proteins such as VN may ultimately prove to be a more effective strategy for developing a wound healing therapy.

Biologic enhancement of wound healing

Manipulation of the healing process through wound supplementation with agents that are natural contributors to the healing process is an appealing concept. Early experimental studies evaluating wounds supplemented with inflammatory mediators used materials extracted from cell preparations and generated encouraging results. Recombinant technology has allowed the production of larger volumes of these mediators that can be used more practically and safely in the clinical setting. Several clinical trials involving inflammatory mediators as wound supplements are reviewed, and the results of many of the studies are encouraging. Wound supplements are considered drugs, and therefore, they must be demonstrated to be safe and efficacious before they can receive approval for human use by the FDA. It is extremely expensive to carry out the experimental studies required for FDA approval. Because of the expense involved, Regranex is the only supplement that has been tested thoroughly enough to receive FDA approval for use in humans. It is hoped that additional agents will be demonstrated to be safe and efficacious in human trials so that they might become available in the United States in the near future.

Optimizing the patient for surgical treatment of the wound

Plastic surgeons are consulted often to close wounds that fail or are difficult to heal. Optimizing the patient's medical condition before surgical closure of a wound can mean the difference between a successful outcome and an undesirable one. It is imperative that plastic surgeons have an extensive knowledge of the modifiable risk factors affecting the wound-healing process and their subsequent complications. This knowledge allows the surgeon to tailor the treatment options and intervene when appropriate to optimize outcomes for successful surgical closure of a wound. Whether the impairments to wound healing and closure are local or systemic, they must be addressed appropriately.

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.

Delivery of plasmid DNA expression vector for keratinocyte growth factor-1 using electroporation to improve cutaneous wound healing in a septic rat model

We have previously shown that wound healing was improved in a diabetic mouse model of impaired wound healing following transfection with keratinocyte growth factor-1 (KGF-1) cDNA. We now extend these findings to the characterization of the effects of DNA plasmid vectors delivered to rats using electroporation (EP) in vivo in a sepsis-based model of impaired wound healing. To assess plasmid transfection and wound healing, gWIZ luciferase and PCDNA3.1/KGF-1 expression vectors were used, respectively. Cutaneous wounds were produced using an 8 mm-punch biopsy in Sprague-Dawley rats in which healing was impaired by cecal ligation-induced sepsis. We used National Institutes of Health image analysis software and histologic assessment to analyze wound closure and found that EP increased expression of gWIZ luciferase vector up to 53-fold compared with transfection without EP (p < 0.001). EP-assisted plasmid transfection was found to be localized to skin. Septic rats had a 4.7 times larger average wound area on day 9 compared with control (p < 0.001). Rats that underwent PCDNA3.1/KGF-1 transfection with EP had 60% smaller wounds on day 12 compared with vector without EP (p < 0.009). Quality of healing with KGF-1 vector plus EP scored 3.0 +/- 0.3 and was significantly better than that of 1.8 +/- 0.3 for treatment with vector alone (p < 0.05). We conclude that both the rate and quality of healing were improved with DNA plasmid expression vector for growth factor delivered with EP to septic rats.

Effects of the basic fibroblast growth factor and its anti-factor in the healing and collagen maturation of infected skin wound

PURPOSE: The infection is one of the main factors that affect the physiological evolution of the surgical wounds. The aim of this work is to evaluate the effects of fibroblast growth factor (FGFâ) and anti-FGFâ in the healing, synthesis and maturation of collagen when topically used on infected skin wounds of rats. METHODS: An experimental study was perfomed in 60 male Wistar rats. All animals were divided in two groups (A and B). Each group was divided in three subgroups A1, B1; A2, B2 and A3, B3. After anesthesia with pentobarbital, two open squared wounds (1cm²), 4cm distant to each other, were done in the dorsal skin of all the rats. In group A (n=30) the wounds were contaminated with multibacterial standard solution, and in group B(n=30) the wounds were maintained sterile. These wounds were named F1 (for inflammation analysis) and F2 (for collagen study). The open wounds of A1 and B1 rats were topically treated with saline solution, A2 and B2 were treated with FGFâ and subgroups A3 and B3 were treated with FGFâ and anti-FGFâ. The rats were observed until complete epitelization of F2 wounds for determination of healing time and the expression of types I and III collagen, using Picro Sirius Red staining. Inflammatory reaction in F1 wounds was studied using hematoxilineosin staining. The three variable was measured by the Image Pro-Plus Média Cybernetics software. The statistical analysis was performed by ANOVA and Tukey test, considering p<0.05 as significant. RESULTS: It was observed that infection retarded significantly (p<0.05) the time of wound scarring and the topical application of FCFb reverted the inhibition of healing caused by bacteria. The inflammatory reaction was greater in the subgroup B2 than in B1 and A3, and the difference was significant (p<0.05). It was observed greater expression of type I collagen in all the subgroups treated with FCFb, when compared with the untreated subgroups. Type III collagen was significantly decreased in wounds of B3 rats, comparing to the other subgroups. CONCLUSIONS: The FCFb accelerated the healing of open infected wounds and contributed with maturation of collagen, enhancing the type I collagen density. The anti-FCFb antibody was able to attenuate the production of both type I and III collagen.

Evidence that PI3K, Rac, Rho, and Rho kinase are involved in basic fibroblast growth factor-stimulated fibroblast–Collagen matrix contraction

Fibroblast-collagen matrix contraction has been used as a model system to study how cells organize connective tissue. Previous work showed that lysophosphatidic acid (LPA)-stimulated floating collagen matrix contraction is independent of Rho kinase while platelet-derived growth factor (PDGF)-stimulated contraction is Rho kinase-dependent. The current studies were carried out to determine the signaling mechanisms of basic fibroblast growth factor (bFGF)-stimulated fibroblast-collagen matrix contraction. Both bFGF and LPA promoted equally collagen matrix contraction well. Three different inhibitors, LY294002 for phosphatidylinositol-3-kinase (PI3K), C3 exotransferase for Rho and Y27632 for Rho kinase, suppressed the bFGF-stimulated fibroblast-collagen matrix contraction. With bFGF stimulation, fibroblasts spread with prominent stress fiber network formation and focal adhesions. In the presence of Rho kinase inhibitor, focal adhesions and stress fibers were mostly lost. We demonstrated that bFGF stimulation for fibroblast caused transient Rac and Rho activation but did not activate Cdc42. In addition, bFGF enhanced fibroblast migration in wound healing assay. The present study implicates PI3K, Rac, Rho, and Rho kinase as being involved in bFGF-stimulated collagen matrix contraction. The elucidation of bFGF-triggered signal transduction may be an important clue to understand the roles of bFGF in wound healing.

Vacuum-assisted closure for the treatment of abdominal wounds

Abdominal wall defects pose a significant surgical challenge. The defect may result from trauma, infections, previous major surgery, or some combination of these etiologies. This article describes the Vacuum-Assisted Closure device (VAC, KCI, San Antonio, Texas) and how it can help in treating these defects.

A study of cytokines released from fibroblasts in cultured dermal substitute

Allogeneic cultured dermal substitute (CDS) was prepared by culturing fibroblasts on a two-layered spongy matrix of hyaluronic acid (HA) and atelo-collagen (Col). CDS can be cryopreserved and transported to other hospitals in a frozen state. The present study was designed to analyze amounts of cytokines released from fibroblasts in fresh or cryopreserved CDS. The culture medium used in preparing CDS over a cultivation period of 1 week (fresh CDS culture medium sample) contained vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), platelet derived growth factor (PDGF)-AA, transforming growth factor (TGF)-beta1, keratinocyte growth factor (KGF), interleukin (IL)-6 and IL-8. After thawing of cryopreserved CDS, the CDS was re-cultured in medium for 1 week. The culture medium used in re-culturing CDS for 1 week (cryopreserved CDS culture medium sample) contained VEGF, bFGF, and HGF in the same concentration as before freezing, and TGF-beta1 and IL-8 at half the concentration before freezing. Levels of PDGF-AA, KGF, and IL-6 were significantly less than before freezing. This finding suggests that the cryopreserved CDS retains its ability to release VEGF, bFGF, and HGF that are essential for wound healing.

The National Pressure Ulcer Long-Term Care Study: outcomes of pressure ulcer treatments in long-term care

OBJECTIVES

To identify resident, wound, and treatment characteristics associated with pressure ulcer (PrU) healing in long-term care residents.

DESIGN

Retrospective cohort study with convenience sampling.

SETTING

Ninety-five long-term care facilities participating in the National Pressure Ulcer Long-Term Care Study throughout the United States.

PARTICIPANTS

Eight hundred eighty-two residents, aged 18 and older, with length of stay of 14 days or longer, who had at least one Stage II to IV PrU.

MEASUREMENTS

Data collected for each resident over a 12-week period included resident characteristics, treatment characteristics, and change in PrU area. Data were obtained from medical records, Minimum Data Set, and other records.

RESULTS

Two multiple regression models, one for each stage grouping (Stage II, Stage III and IV), were completed. The area of Stage II PrU was reduced more with moist (F=21.91, P<.001) than with dry (F=13.41, P<.001) dressings. PrUs cleaned with saline or soap showed less decrease in area (F=12.34, P<.001) than PrUs cleaned with other cleansers such as antiseptic, antibiotic, or commercial cleansers. Change in area of Stage III and IV PrUs was related to sufficient enteral feeding (F=5.23, P=.02), enteral feeding without higher acuity levels (F=3.94, P=.048), size of PrU (very large (F=120.89, P=.001) and large (F=27.82, P=.001)), and type of dressing (moist (F=14.70, P<.001) and dry (F=5.88, P=.02)). Stage III and IV PrUs increased in area when debrided (F=5.97, P=.02). The overall models were significant (Stage III and IV, F=20.30, coefficient of determination (R2)=0.06, P<.001; Stage II, F=40.28, R2=0.13, P<.001) but explained little of the variation in change in PrU area.

CONCLUSION

In this sample of nursing facility residents, use of moist dressings (Stage II, Stage III and IV) and adequate nutritional support (Stage III and IV) are strong predictors of PrU healing.

Prevention and Treatment of Pressure Ulcers

Pressure ulcers are complex chronic wounds for which no gold standard for prevention or treatment has yet been established. Several attempts at developing guidelines has been undertaken by different organizations. Pressure ulcers are devastating comorbidities for patients and difficult to prevent or manage. Whether or not pressure ulcers are preventable remains controversial. The strategy for prevention includes recognizing the risk, decreasing the effects of pressure, assessing nutritional status, avoiding excessive bed rest and prolonged sitting, and preserving the integrity of the skin. The principles of treatment of pressure ulcers include assessing severity, reducing pressure, friction and shear forces, optimizing local wound care, removing necrotic debris, managing bacterial contamination, and correcting nutritional deficits.

Mortality and recurrence rate after pressure ulcer operation for elderly long-term bedridden patients

We operated on 16 sacral pressure ulcers in elderly and long-term residential patients who were immobile as a result of cerebral vascular disease. The mean age of patients was 76 years. Eight ulcers were treated with local fascial flaps and 8 by simple closure. The follow-up period was from 1 to 4 years. Recurrence and mortality rates were examined retrospectively. In the 16 patients, recurrence occurred in 37.5%, and 43.8% died without recurrence. The recurrence rate was 37.5% for local fascial flaps and 37.5% for simple closure. Overall mortality was 68.8% in the follow-up period. Because postoperative death was common, we should not only focus on reducing local pressure but also pay attention to any underlying disease. Because of this high mortality rate, the least invasive procedure possible should be used. Because the recurrence rate of simple closure was the same as for local fascial flaps, simple closure should be considered as a reconstructive method.

Treatment of pressure ulcers with topical negative pressure versus traditional wound management methods: a research sampler

The treatment of pressure ulcers is still a matter of debate. The pros and cons of topical negative pressure versus traditional saline wet-to-moist dressings, platelet-derived growth factor, and surgical debridement are discussed in the literature review. This article examines literature that relates to the mechanism of action and efficacy of topical negative pressure.

The effects of basic fibroblast growth factor on postoperative mastoid cavity problems

OBJECTIVES

To present the effects of basic fibroblast growth factor on intractable cavity problems and discuss the mechanisms of its effects.

METHODS

We treated three ears with postoperative open cavities. All three cases had suffered from chronic discharge of the ear for 7, 10, and 30 years, respectively; 100 microg/ml of trafermin (genetic recombination) solution, as basic fibroblast growth factor, was dropped into the open cavity once daily. If bacterial and/or fungal infection was observed, antibiotics and/or antifungal agents were administered locally twice daily.

RESULTS

The cavities epithelialized and were cured within 2 months using this treatment.

CONCLUSION

Our results suggest that basic fibroblast growth factor stimulates the proliferation and differentiation of keratinocytes, fibroblasts, and endothelial cells, leading to accelerated wound healing. The basic fibroblast growth factor agent appears to be highly effective in treating intractable cavity problems.

Motogenic substrata and chemokinetic growth factors for human skin cells

Extracellular matrix remodelling and accurate spatio-temporal coordination of growth factor expression are two factors that are believed to regulate mitoses and cell migration in developing and regenerating tissues. The present quantitative videomicroscopical study examined the influence of some of the principal components of extracellular matrix and several growth factors that are known to be expressed in dermal wounds on three important facets of human skin cell behaviour in culture. Keratinocytes, melanocytes and dermal fibroblasts (and myofibroblast controls) exhibited varying degrees of substrate adhesion, division and migration depending on the composition of the culture substrate. Substrates that are recognized components of transitional matrices generally accentuated cell adhesion and proliferation, and were motogenic, when compared with serum-treated control surfaces, whereas components of more stable structures such as basement membrane had less influence. Platelet-derived growth factor (PDGF), epidermal growth factor (EGF) and alpha fibroblastic growth factor (alphaFGF) all promoted cell proliferation and were chemokinetic to dermal fibroblasts, but not keratinocyte growth factor (KGF) or transforming growth factor beta (TGFbeta). PDGF, EGF and KGF, but not TGFbeta or alphaFGF, all enhanced proliferation of dermal keratinocytes. The same growth factors, and in addition KGF, all stimulated motility in keratinocytes, but TGFbeta and alphaFGF again had no effect. Developing a better understanding of the interdependency of factors that control crucial cell behaviour may assist those who are interested in the regulation of histogenesis and also inform the development of rational therapeutic strategies for the management of chronic and poorly healed wounds.

LETTER TO THE EDITOR: The Other Side: Failure in Fair and Balanced Reporting

Matrix metalloproteinases (MMPs) and their tissue inhibitors play important roles in the wound-healing process. An imbalance in the expression of these molecules is thought to contribute to the failure of chronic ulcers to heal. We investigated whether a mitogenic bovine whey extract enriched with growth factors modulated the expression and activity of MMP-2 and -9, and the tissue inhibitor of MMP-2 (TIMP-2) in chronic leg ulcers. Wound fluids and biopsies were collected from chronic leg ulcer patients whose ulcers were treated topically for 4 weeks with placebo or mitogenic bovine whey extract at concentrations of 2.5, 10, and 20 mg/mL. The levels of MMP-2 and -9 in wound fluid samples was assessed by gelatin zymography and showed a decrease in active MMP-2 in the 2.5 and 10.0 mg/mL mitogenic bovine whey extract-treated ulcers compared with placebo (p<0.05). Immunohistochemical analysis of ulcer biopsies for MMP-2, -9, and TIMP-2 expression showed a reduction in the number of MMP-2-positive dermal fibroblasts in the mitogenic bovine whey extract-treated ulcers compared with pretreatment biopsies (p<0.05) that persisted over the course of the study. In contrast, a transient increase in the number of MMP-9- and TIMP-2-positive cells was observed in mitogenic bovine whey extract treated ulcer biopsies compared with pretreatment levels (p<0.05). These results show that topical application of mitogenic bovine whey extract was able to modulate the expression of MMP-2, -9, and TIMP-2 in chronic leg ulcers and that its constituent growth factors may have the potential to redress the proteolytic imbalance observed in nonhealing chronic ulcers.

Repair of intractable cerebrospinal fluid rhinorrhea with mucosal flaps and recombinant human basic fibroblast growth factor: technical case report

OBJECTIVE AND IMPORTANCE

Repair of a cerebrospinal fluid leak is not always easy, especially when a large fistula, with concomitant infection and injured mucosa, has developed from repeated transsphenoidal operations. We repaired such a sellar floor defect with mucosal flaps via the endonasal endoscopic approach and finally obliterated the fistula by promoting granulation-like tissue formation with recombinant human basic fibroblast growth factor (bFGF).

CLINICAL PRESENTATION

A 27-year-old woman with intractable cerebrospinal fluid rhinorrhea was referred to our department after repeated operations for a relapsing Rathke's cleft cyst. Endonasal endoscopic examination revealed a large bone defect on the sellar floor through which previously packed fat and fascia were exposed to the nasal cavity.

INTERVENTION

Mucosal flaps were harvested endoscopically from the nasal septum and the superior and middle turbinates. These pedicled flaps were transposed to the sellar defect. The flaps survived but did not cover the whole area, resulting in gaps between the flaps through which cerebrospinal fluid still leaked. Recombinant bFGF was repeatedly applied endoscopically to the mucosal flaps. The flaps turned into granulation-like tissue, and complete mucosal covering was finally achieved.

CONCLUSION

bFGF has a wide range of biological effects, including stimulation of fibroblast growth and promotion of angiogenesis. It accelerates wound healing and is used clinically to treat dermal ulcers. The method presented here to treat an intractable fistula with mucosal flap and recombinant bFGF may suggest a new clinical application of bFGF. This possibility should be examined in a large number of patients in the future.

Mechanics of wound healing and importance of Vacuum Assisted Closure in urology

PURPOSE

We discuss the mechanisms of wound healing and our experience with the Vacuum Assisted Closure device (Kinetic Concepts, Inc., San Antonio, Texas) for complex urogenital wounds.

MATERIALS AND METHODS

The literature obtained from a Medline search on wound healing, wound failure and vacuum assisted closure was reviewed. In addition, we reviewed our experience with negative pressure wound therapy.

RESULTS

Wound healing is a complex interaction between the reticuloendothelial and immune systems, in addition to correctable internal and external factors. Understanding the healing process improves outcomes and decreases patient morbidity. Negative pressure wound therapy has hastened wound healing and it adds significant improvement in the arsenal of choices available.

CONCLUSIONS

Vacuum Assisted Closure is a therapeutic alternative that complements surgical and medical intervention in patients with complex wounds.

Wound Healing Enhancement: Electroporation to Address a Classic Problem of Military Medicine

The major goal of wound healing biology is to determine how a wound can be induced to repair damaged tissue faster and more efficiently. Enhancement of dermal and epidermal regeneration is an extremely important goal for the treatment of many different types of wounds. Exogenous application of growth factors to the wound site has been shown to have potential to improve wound healing. Frequent applications of large amounts of growth factor have been required. This is because proteases in the wound quickly destroy peptide growth factor. Gene therapy has the potential to produce growth factors deep within the wound, where they can be effective as well as able to constantly replenish growth factor that is destroyed by peptidases. We have shown that application of plasmid DNA expression vectors directly into the wound is an inefficient modality. Electroporation, the application of an electrical field across cells to permeabilize the cell membrane has led us to explore the possibility of utilizing the technique to enhance transfection efficiency. We have identified electroporation parameters that improve the efficiency of DNA transfection in cutaneous wounds, and we have shown that electroporation itself does not impair wound healing. We are now on the threshold of exploring whether electroporation-assisted transfection with DNA plasmid expression vectors for growth factors will be an effective modality for enhancing cutaneous wound healing.

Engineered growth factors and cutaneous wound healing: Success and possible questions in the past 10 years

In the past 10 years, many engineered growth factors, including recombinant human epidermal growth factor, basic fibroblast growth factor, and platelet-derived growth factor, have been produced and used in the clinic. After screening the results from different centers, some results are found to be encouraging, while others are discouraging. Although the interpretation of these results may depend on your perspective, it may also depend on different criteria, different wounds, and even different aims. In this article, successful experiences and failures concerning the use of growth factors and cutaneous wound healing are summarized. Based on this information and our clinical experience, we address people's concerns such as whether growth factors have altered clinical practice thus far and whether growth factor treatments have solved all problems involved in wound healing. Is there a need for exogenous application of growth factors in acute or chronic wounds, and if so, is it safe to use growth factors to promote wound healing? Last, can we achieve perfect wound healing in those wounds treated with growth factors?