The role of surgical debridement in healing of diabetic foot ulcers

An estimated 15% of patients with diabetes mellitus will develop a foot ulcer during their lifetime. Debridement is included in multiple guidelines and algorithms for the care of patients with diabetic neuropathic foot ulcers, and it has long been considered an essential step in the protocol for treating diabetic foot ulcers. In addition to altering the environment of the chronic wound, debridement is a technique aimed at removing nonviable and necrotic tissue, thought to be detrimental to healing. This is accomplished by removing abnormal wound bed and wound edge tissue, such as hyperkeratotic epidermis (callus) and necrotic dermal tissue, foreign debris, and bacteria elements known to have an inhibitory effect on wound healing. While the rationale for surgical debridement seems logical, the evidence for its role in enhancing healing is deficient. In this paper, we systematically review five published clinical trials, which met the criteria and investigated surgical debridement of diabetic foot ulcers to enhance healing. Most existing studies are not randomized clinical trials optimized to test the relationship between debridement of diabetic foot ulcers and wound healing. Therefore, a focused, well‐designed study is needed to elucidate the effect of surgical debridement on the healing status of chronic wounds.     

Enzymatic wound debridement

BACKGROUND: Clinical experience and existing research strongly support debridement as a necessary component of wound bed preparation when slough or eschar is present. Multiple techniques are available, but the indications for each technique and their efficacy are not clearly established. There is little evidence to guide the clinician in the selection of a safe, effective debridement method for the patient with a chronic wound. OBJECTIVES: We sought to identify evidence related to the efficacy of enzymatic debriding agents collagenase and papain-urea in the removal of necrotic tissue from the wound bed and its impact on wound healing. SEARCH STRATEGY: A systematic review of electronic databases was undertaken using key words: (1) debridement, (2) enzymatic debridement, (3) collagenases, (4) papain, (5) urea, and (6) papain-urea. All prospective and retrospective studies that compared enzymatic debridement using collagenase or papain-urea (with and without chlorophyllin) on pressure ulcers, leg ulcers, or burn wounds were included in the review. All studies that met inclusion criteria and were published between January 1960 and February 2008 were included. RESULTS: Collagenase ointment is more effective than placebo (inactivated ointment or petrolatum ointment) for debridement of necrotic tissue from pressure ulcers, leg ulcers, and partial-thickness burn wounds. Limited evidence suggests that a papain-urea-based ointment removes necrotic material from pressure ulcers more rapidly than collagenase ointment, but progress toward wound healing appears to be equivocal. Limited evidence suggests that treatment of partial-thickness burn wounds in children with collagenase ointment may require an equivocal time to treatment with surgical excision and that combination treatment may reduce the need for surgical excision. Insufficient evidence was found to determine whether collagenase ointment removes necrotic tissue from leg ulcers more or less rapidly than autolytic debridement enhanced by a polyacrylate dressing. IMPLICATIONS FOR PRACTICE: Enzymatic debriding agents are an effective alternative for removing necrotic material from pressure ulcers, leg ulcers, and partial-thickness wounds. They may be used to debride both adherent slough and eschar. Enzymatic agents may be used as the primary technique for debridement in certain cases, especially when alternative methods such as surgical or conservative sharp wound debridement (CSWD) are not feasible owing to bleeding disorders or other considerations. Many clinicians will select enzymes when CSWD is not an option. Clinical experience strongly suggests that combined therapy, such as initial surgical debridement followed by serial debridement using an enzymatic agent or enzymatic debridement along with serial CSWD, is effective for many patients with chronic, indolent, or nonhealing wounds.     

Serial surgical debridement: A retrospective study on clinical outcomes in chronic lower extremity wounds

This investigation was conducted to determine if a correlation exists between wound healing outcomes and serial debridement in chronic venous leg ulcers (VLUs) and diabetic foot ulcers (DFUs). We retrospectively analyzed the results from two controlled, prospective, randomized pivotal trials of topical wound treatments on 366 VLUs and 310 DFUs over 12 weeks. Weekly wound surface area changes following debridement and 12-week wound closure rates between centers and patients were evaluated. VLUs had a significantly higher median wound surface area reduction following clinical visits with surgical debridement as compared with clinical visits with no surgical debridement (34%, p =0.019). Centers where patients were debrided more frequently were associated with higher rates of wound closure in both clinical studies ( p =0.007 VLU, p =0.015 DFU). Debridement frequency per patient was not statistically correlated to higher rates of wound closure; however, there was some minor evidence of a positive benefit of serial debridement in DFUs (odds ratio—2.35, p =0.069). Our results suggest that frequent debridement of DFUs and VLUs may increase wound healing rates and rates of closure, though there is not enough evidence to definitively conclude a significant effect. Future clinical research in wound care should focus on the relationship between serial surgical wound debridement and improved wound healing outcomes as demonstrated in this study.     

Relationship Between pH Shifts and Rate of Healing in Chronic Nonhealing Venous Stasis Lower-Extremity Wounds

Venous stasis ulcers represent the majority of lower-extremity ulcers and place a considerable financial burden on the American health care system. Current standard of care therapies remain sub-optimal with 50% of venous stasis ulcers remaining unhealed after 4 months. Sixteen consecutive wounds were enrolled across 8 participants at a single center and underwent pH-driven therapy in addition to standard care as dictated by physicians. Following wound debridement, the pH of the wound bed was measured using pH strips. If acidic, normal saline was used to rinse the wound at every dressing change. If alkaline, nonsterile gauze was soaked in 0.25% acetic acid and applied to the wound for a minimum of 30 seconds. Participants were followed for 4 weeks with research staff observing compliance throughout. All 16 wounds had an alkaline pH at baseline, with an average pH of 8.25 ± 0.55 (range 7.5 to 9). Average area of the wound at the time of enrollment was (mean ± standard deviation) 285.48 ± 43.68 mm², and average age of the wound was 37.5 ± 20.3 months (range 3 to 72). A simple linear regression model found a moderate relationship between pH and the rate of healing of chronic nonhealing venous stasis lower-extremity wounds (correlation coefficient = 0.61). For every 1-unit change in pH, we can expect to see a change in wound size of 116.05 mm². This is the first US-based, open-label, prospective study that examined the effect of pH on the rate of healing in chronic nonhealing venous stasis ulcer lowerextremity wounds.     

Evaluation of wound fluid biomarkers to determine healing in adults with venous leg ulcers: A prospective study

Clinical practice guidelines recommend using repeated wound surface area measurements to determine if a chronic ulcer is healing. This results in delays in determining the healing status. This study aimed to evaluate whether any of a panel of biomarkers can determine the healing status of chronic venous leg ulcers. Forty‐two patients with chronic venous leg ulcers had their wound measured and wound fluid collected at weekly time points for 13 weeks. Wound fluid was analyzed using multiplex enzyme‐linked immunosorbent assay to determine the concentration of biomarkers in the wound fluid at each weekly time point. Healing status was determined by examining the change in wound size at the previous and subsequent weeks. Predictive accuracy with 95% confidence intervals (CI) is reported. Of 42 patients, 105 evaluable weekly time points were obtained, with 32 classified as healing, 27 as nonhealing, and 46 as indeterminate. Thirteen biomarkers significantly differed between healing and nonhealing wounds (p < 0.1) and were included in a multivariate logistic regression model. Granulocyte macrophage‐colony stimulating factor (p < 0.001) and matrix metalloprotease‐13 (p = 0.004) were the best predictors of wound healing. Receiver operating characteristic curves indicated 92% accuracy (95% CI: 85%,100%) for granulocyte macrophage‐colony stimulating factor, and 78% accuracy (95% CI: 65%,90%) for matrix metalloprotease‐13 in discriminating between healing and nonhealing wounds. This study found that two biomarkers from wound fluid can predict healing status in chronic venous leg ulcers. These findings may lead to the ability to determine the future trajectory of a wound and the ability to modify treatment accordingly.     

Effective use of negative pressure wound therapy provides quick wound-bed preparation and complete graft take in the management of chronic venous ulcers

Venous ulcers are characterised by longstanding and recurrent loss of skin integrity. Once occurred, healing is slow and recurrence is high because of inappropriate conditions of the wound bed. This study involves 20 patients with chronic venous ulcers at least 6 weeks of duration treated with negative pressure wound therapy (NPWT). Patients underwent a radical debridement of all devitalised tissues in the first operation. After adequate haemostasis, silver-impregnated polyurethane foam was applied. Once the wounds were determined to be clean and adequate granulation tissue formation was achieved, split-thickness skin grafts were applied. Black polyurethane foam was applied over them. All wounds completely healed without the need for further debridement or regrafting. The mean number of silver-impregnated foam dressing changes prior to grafting was 2·9 (one to eight changes). The mean number of NPWT foam changes was 2·6 after skin grafting (two to five changes). Two patients who did not use conservative treatments for chronic venous insufficiency (CVI) after discharge from the hospital had recurrence of venous ulcers in the follow-up period. Application of NPWT provides quick wound-bed preparation and complete graft take in venous ulcer treatment.     

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.     

Mitogenic activity and cytokine levels in non-healing and healing chronic leg ulcers

The cause of impaired healing in chronic leg ulcers is not known. However, recent attempts to modify the healing process have focused on adding growth factors to stimulate healing and have failed to produce dramatic improvements in healing. This study used a unique model of chronic wound healing in humans to obtain wound fluid samples from chronic venous leg ulcers that had changed from a nonhealing to a healing phase. These samples were used to assess cytokine and growth factor levels, and mitogenic activity in these nonhealing and healing chronic wounds. The pro-inflammatory cytokines interleukin-1, interleukin-6 and tumor necrosis factor-alphawere found to be present in significantly higher concentrations in wound fluid from nonhealing compared to healing leg ulcers. There were detectable levels but, no significant change in the levels of platelet derived growth factor, epidermal growth factor, basic fibroblast growth factor or transforming growth factor-betaas ulcers healed. Wound fluid was added to fibroblasts in vitro to assess mitogenic activity. There was a significantly greater proliferative response to healing wound fluid samples compared to nonhealing samples. These results suggest that healing may be impaired by inflammatory mediators rather than inhibited by a deficiency of growth factors in these chronic wounds.     

Topically applied rhGM-CSF for the wound healing: a systematic review

The process of wound healing involves a complex interplay of cells, mediators, growth factors and cytokines. GM-CSF has been shown to be involved in a number of processes essential in this event. Topically applied rhGM-CSF has been reported to successfully treat wounds with diverse etiology, including burns, chronic venous leg ulcers, pressure ulcers, and leprosy ulcers, both in animal experiments and clinical studies. To evaluate the effect of the rhGM-CSF on wound healing, 8 RCT studies and 23 clinical studies and case reports are collected for analysis of the evidence. The overall effects of rhGM-CSF on the healing of wound are diverse. Topically applied rhGM-CSF is beneficial for deep partial-thickness burn wounds, chronic leg ulcers, and leprosy ulcers. rhGM-CSF may have a positive effect on other type of chronic ulcers such as pressure ulcers and cancer related ulcers, but the evidence is not sufficient for generalised use at present. rhGM-CSF is suggested have no accelerating effect on the healing of healthy wounds or surgical incisions.     

Erbium: Yttrium Aluminum Garnet Laser Accelerates Healing in Indolent Diabetic Foot Ulcers

The objective of the study was to evaluate the effect of the erbium:yttrium aluminum garnet (YAG) laser on diabetic foot ulcers (DFUs) that had not responded to standard care. We retrospectively evaluated 22 nonhealing DFUs that received at least 4 weeks of standard wound care, demonstrated poor healing response, and subsequently were treated with an erbium:YAG laser. We measured the percent wound area reduction (PWAR) for the 4 weeks before initiating laser therapy and the PWAR for 4 weeks after the initiation of laser therapy. Erbium:YAG laser treatment consisted of 2 components: debridement and resurfacing. The laser settings were the same for all treatments. We used the paired t test to compare pretreatment with posttreatment wound area reduction. During the 4-week period before the initiation of laser therapy, the average PWAR was –33.6%. Four weeks after initiating treatment with the erbium:YAG laser, the average PWAR was 63.4% (p = .002) and 72.7% of wounds had ≥50% PWAR. By 12 weeks, 50% of wounds had healed. Erbium:YAG laser therapy accelerated DFU healing in a cohort of patients with ulcers that had been unresponsive to standard of care therapy.     

Analysis of the acute and chronic wound environments: the role of proteases and their inhibitors

To assess the differences in proteolytic activity of acute and chronic wound environments, wound fluids were collected from acute surgical wounds (22 samples) and chronic wounds (25 samples) of various etiologies, including mixed vessel disease ulcers, decubiti and diabetic foot ulcers. Matrix metalloproteinase (MMP) activity measured using the Azocoll assay was significantly elevated by 30 fold in chronic wounds (median 22.8 microg MMP Eq/ml) compared to acute wounds (median 0.76 microg MMP Eq/ml) (p < 0.001). The addition of the matrix metalloproteinase inhibitor Illomostat decreased the matrix metalloproteinase activity by approximately 90% in all samples, confirming that the majority of the activity measured was due to matrix metalloproteinases. Gelatin zymograms indicated predominantly elevated matrix metalloproteinase-9 with smaller elevations of matrix metalloproteinase-2. In addition tissue inhibitor of metalloproteinase-1 levels were analyzed in a small subset of acute and chronic wounds. When tissue inhibitor of metalloproteinase-1 levels were compared to protease levels there was an inverse correlation (p = 0.02, r = - 0.78). In vitro degradation of epidermal growth factor was measured by addition of 125I labelled epidermal growth factor to acute and chronic wound fluid samples. There was significantly higher degradation of epidermal growth factor in chronic wound fluid samples (mean 28.1%) compared to acute samples (mean 0.6%). This also correlated to the epidermal growth factor activity of these wound fluid samples (p < 0. 001, r = 0.64). Additionally, the levels of proteases were assayed in wound fluid collected from 15 venous leg ulcers during a nonhealing and healing phase using a unique model of chronic wound healing in humans. Patients with nonhealing venous leg ulcers were admitted to the hospital for bed rest and wound fluid samples were collected on admission (nonhealing phase) and after 2 weeks (healing phase) when the ulcers had begun to heal as evidenced by a reduction in size (median 12%). These data showed that the elevated levels of matrix metalloproteinase activity decreased significantly as healing occurs in chronic leg ulcers (p < 0.01). This parallels the processes observed in normally healing acute wounds. This data also supports the case for the addition of protease inhibitors in chronic wounds in conjunction with any treatments using growth factors.     

Topical oxygen therapy results in complete wound healing in diabetic foot ulcers

Diabetic foot ulcers (DFUs) are a significant problem in an aging population. Fifteen percent of diabetics develop a DFU over their lifetime, which can lead to potential amputation. The 5‐year survival rate after amputation is 31%, which is greater than the lifetime risk of mortality from cancer. Topical oxygen is a promising technique for the adjunctive therapy of chronic wounds including DFUs, but few controlled studies exist to support its clinical adoption. The aim of this study was to compare a portable topical oxygen delivery system in patients with nonhealing DFUs to standard best practice. Twenty patients were randomized into a topical oxygen group (n = 10), and a nonplacebo control group with regular dressings and standard care (n = 10), and attended the diabetic foot clinic once weekly for 8 weeks. Ulcer surface area over time was analyzed using standardized digital imaging software. DFUs were present without healing for a mean duration of 76 weeks prior to the study. They found a significant difference in healing rate between patients receiving topical oxygen and those receiving standard care. Topical oxygen, therefore, represents a potentially exciting new technology to shorten healing time in patients with nonhealing DFUs. More prospective randomized and powered studies are needed to determine the benefits of topical oxygen, but our current results are very promising.     

Maggot therapy for foot and leg wounds

Maggot debridement therapy has been used for more than 70 years to treat nonhealing soft tissue wounds. Blowfly larvae are used to debride, disinfect, and promote healing of chronic wounds. The use of maggot therapy is on the rise, owing to recognized limitations in our current medical and surgical wound care options. Anecdotal evidence of maggot therapy efficacy is plentiful, but large prospective comparative clinical trials are desperately needed. Until data from such studies become available, treatment criteria and safety data must be derived from retrospective studies, case series, and other published accounts. Based on these limited sources of data,treatment guidelines are proposed for the safe and effective use of maggots for treating problematic foot and leg wounds.     

Adipose-derived stem cells for wound healing applications

Nonhealing wounds remain a significant challenge for plastic surgeons. More than 600,000 people suffer from venous ulcers and 1.5 to 3 million people are being treated for pressure sores every year in the United States. The use of tissue engineering techniques such as stem-cell therapy and gene therapy to improve wound healing is a promising strategy. Adipose tissue represents a source of cells that may be able to enhance wound healing. Adipose-derived stem cells (ASCs) are adult stem cells that are easily harvested and of great interest for plastic surgeons. Specifically, ASCs secrete angiogenic growth factors that can induce tissue regeneration. This review describes innovative research strategies using ASCs therapies for treatment of chronic, nonhealing wounds.     

High‐dose folic acid and its effect on early stage diabetic foot ulcer wound healing

High‐dose folic acid (HDFA; vitamin B9)—5 mg, given daily, has not been evaluated as a treatment to improve early stage‐diabetic foot ulcer (ES‐DFU) wound healing. However, HDFA has been demonstrated to correct: (a) endothelial dysfunction and decreased nitric oxide (NO) bioavailability, associated with type‐2 diabetes mellitus (T2DM); and (b) hyperhomocysteinemia (HHcy) that may promote impaired DFU‐wound healing. Measures of wound area (cm²) reduction (wound closure; WC), over a 4‐week period (4 W‐WC), greater than 50% of the wound area, have been reported as a robust indicator of the potential for DFU‐wound healing. By using this model, we examined the effectiveness of a wound treatment in promoting progressive healing and complete wound closure for the chronic, nonhealing DFU‐wound. To investigate this possible relationship between HDFA and ES‐DFU wound healing, a retrospective cohort study of medical records, between November 2018 and April 2019, was performed for Veterans with T2DM and ES‐DFUs following treatment with HDFA. During the study period 29 (n = 29) Veterans with ES‐DFU wounds who received HDFA treatment were identified. Medical record reviews of this retrospective cohort of ES‐DFU Veterans receiving HDFA report 90% (26/29) experiencing complete DFU‐wound closure during the study period. Of the 29 Veterans with ES‐DFUs receiving HDFA, the medical records of nine (30%), with healed wounds, provided documentation suitable for 4 W‐WC, pre‐ and post‐HDFA treatment study comparisons. This study documents significant (P < .05) improvements comparing 4 W‐WC values for standard treatment for Veterans with poorly progressing, worsening or stagnating ES‐DFU‐wounds to those for the same subjects following HDFA treatment. These observations suggest that chronic ES‐DFUs treated with HDFA may experience significantly improved wound closure and complete healing (re‐epithelialization) when compared with standard treatments without HDFA. With validation from RCTs, HDFA may be established as an effective treatment to promote wound healing and closure for nonhealing ES‐DFUs.     

Ability of chronic wound fluids to degrade peptide growth factors is associated with increased levels of elastase activity and diminished levels of proteinase inhibitors

The stability of peptide growth factors exposed to fluids from healing surgical wounds and from nonhealing chronic wounds was examined in vitro. (125)I-Labeled transforming growth factor-beta1 or platelet-derived growth factor-BB was incubated with fluids from healing surgical wounds and fluids from venous stasis or pressure ulcers. Fluids from healing surgical wounds had no appreciable effect on the level of (125)I corresponding to intact growth factor. In contrast, incubation with fluids from several venous stasis or pressure ulcers resulted in significant degradation of these growth factors. Degradation was blocked by broad-spectrum serine proteinase inhibitors and by specific inhibitors of neutrophil elastase. Levels of elastase activity in wound fluids correlated with the ability to degrade peptide growth factors. Further comparisons showed qualitative and quantitative differences in the endogenous proteinase inhibitors, alpha2-macroglobulin and alpha1-antiproteinase. These results could explain, in part, the variable growth factor levels which have been found in chronic wounds. More importantly, the ability of some chronic nonhealing wounds to rapidly degrade exogenously added growth factors has important implications with regard to past and future clinical attempts to use peptide growth factors to treat these types of problem wounds.     

New techniques for wound debridement

Debridement is a crucial component of wound management. Traditionally, several types of wound debridement techniques have been used in clinical practice such as autolytic, enzymatic, biodebridement, mechanical, conservative sharp and surgical. Various factors determine the method of choice for debridement for a particular wound such as suitability to the patient, the type of wound, its anatomical location and the extent of debridement required. Recently developed products are beginning to challenge traditional techniques that are currently used in wound bed preparation. The purpose of this review was to critically evaluate the current evidence behind the use of these newer techniques in clinical practice. There is some evidence to suggest that low frequency ultrasound therapy may improve healing rates in patients with venous ulcers and diabetic foot ulcers. Hydrosurgery debridement is quick and precise, but the current evidence is limited and further studies are underway. Debridement using a monofilament polyester fibre pad and plasma‐mediated bipolar radiofrequency ablation are both very new techniques. The initial evidence is limited, and further studies are warranted to confirm their role in management of chronic wounds.     

Randomized trial and local biological effect of autologous platelets used as adjuvant therapy for chronic venous leg ulcers

OBJECTIVES: Platelet products have been proposed as adjuvant therapy for wound healing. We undertook this study to determine the healing effect of topically applied frozen autologous platelets (FAP) on chronic venous ulcers, compared with effect of placebo, and whether use of topical FAP modifies local expression of vascular endothelial growth factor (VEGF), keratinocyte growth factor (KGF), interleukin 8 (IL-8), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in wound fluid. METHODS: This randomized, placebo-controlled, double-blind trial was carried out in institutional practice, with ambulatory patients with proved chronic venous leg ulcers. In all patients, whole venous blood was drawn for preparation of FAP. FAP or normal saline solution was applied three times per week for up to 12 weeks, together with hydrocolloids and standardized compression bandages. Leg ulcer surface was assessed with numerical pictures. IL-8, VEGF, KGF, and TIMP-1 levels were determined (enzyme-linked immunosorbent assay) in wound fluid after each 4 weeks of treatment. RESULTS: Fifteen patients were randomized into two groups with comparable leg ulcer characteristics. Mean percent reduction in ulcer area was 26.2% in the FAP group versus 15.2% in the placebo group (P =.94). One ulcer in each group was completely healed at study end. Levels of TIMP-1 increased significantly during FAP treatment. IL-8 concentration was significantly lower in wound fluid of healing ulcers than in the fluid of nonhealing ulcers, in both FAP and placebo groups. Growth factor levels were not modified with FAP treatment. CONCLUSION: Topical autologous platelets have no significant adjuvant effect on healing of chronic venous leg ulcers and increased wound fluid TIMP-1 concentration. Ulcer healing is associated with a decrease in wound fluid IL-8.     

Allogeneic keratinocyte for intractable chronic diabetic foot ulcers: A prospective observational study

Chronic diabetic foot ulcers (DFUs) are a common problem in patients with diabetes and are often difficult to treat. The application of newly developed dressing material in patients with chronic DFUs has been reported to be effective. The purpose of this study was to evaluate the usefulness of allogeneic keratinocyte treatment for chronic DFUs. We performed weekly allogeneic keratinocyte treatment for up to 12 weeks in 71 patients with intractable DFUs. We investigated healing rate, wound‐healing velocity, and time to 50% wound size reduction and analysed factors affecting ulcer healing. Fifty‐six patients (78.8%) had complete wound healing. Forty‐six patients (64.7%) showed complete healing within an average of 6.1 weeks, and 10 patients (14.1%) showed partial healing with an average 35.5% reduction vs initial size at the end of follow up. The 10 patients who showed partial healing continued to receive treatment after the 12‐week study period. The mean time to complete wound healing was 7.8 weeks. Fifteen patients (21.1%) experienced treatment failure because of infection, local necrosis, no change in ulcer size, or osteomyelitis during the follow‐up period. No adverse events were observed. Allogeneic keratinocyte treatment is effective for chronic, difficult‐to‐treat DFUs.     

Lower levels of PAI-2 may contribute to impaired healing in venous ulcers - a preliminary study

Plasminogen activators may potentially influence the wound healing processes of cell migration, matrix degradation and cellular adhesion in venous ulcers by their regulation of protease activity. The aim of this study was to assess the levels of plasminogen activators in venous ulcers and to gain preliminary data from healing wounds.The concentrations of u-PA, t-PA, PAI-1 and PAI-2 antigen as well as functional u-PA were assessed in tissue homogenates from 20 chronic venous ulcers, six actively healing venous ulcers and five traumatic wounds.The concentrations of functional u-PA, u-PA antigen and PAI-1 were significantly greater and PAI-2 was significantly lower in the edge and base of chronic venous ulcers compared to adjacent intact skin (P<0.01). Healing wounds had significantly higher functional u-PA at the ulcer edge and higher u-PA antigen concentration in intact skin (P<0.05). PAI-2 levels were significantly higher in the ulcer edge and base in the healing wounds than in chronic venous ulcers (P<0.05).These findings suggest that regulation of protease activity by u-PA and PAI-2 may play a role in the impaired healing of chronic venous ulcers.