Cost-Effectiveness of Hypochlorous Acid Preserved Wound Cleanser versus Saline Irrigation in Conjunction with Ultrasonic Debridement for Complex Wounds.

Objective: Low-frequency ultrasound debridement with irrigation is an effective method of wound bed preparation. A recent clinical study compared hypochlorous acid preserved wound cleanser (HAPWOC) to saline and found HAPWOC to be a more effective adjunct to low frequency ultrasound debridement. However, HAPWOC has an added cost. The primary objective of this study was to assess the cost-effectiveness of HAPWOC as an irrigation modality with low-frequency ultrasound debridement for the treatment of severely complex wounds that were destined to be closed primarily via a flap. The secondary objective of this study was to estimate the number needed to treat (NNT) to avoid a wound-related complication and its expected cost per NNT. Methods: A patient-level Monte-Carlo simulation model was used to conduct a cost-effectiveness analysis from the US health system perspective. All clinical data were obtained from a prospective clinical trial. Cost data were obtained from the publicly available data sources in 2021 US dollars. The effect measure was the avoidance of wound-related complications at 14-days post-debridement. The primary outcome was the incremental cost-effectiveness ratio (ICER), a measure of the additional cost per benefit. The secondary outcomes were the NNT and expected cost per NNT to avoid one complication (complementary to the ICER in assessing cost-effectiveness). Deterministic and probabilistic sensitivity analyses (PSA) were performed to gauge the robustness and reliability of the results. Results: The ICER for HAPWOC versus saline irrigation was US$90.85 per wound complication avoided. The expected incremental cost per patient in the study and effect was US$49.97 with 55% relative reduction in wound-related complications at day 14 post debridement procedure. The NNT and cost per NNT were 2 and US$99.94, respectively. Sensitivity analyses demonstrated that these results were robust to variation in model parameters. Conclusion: HAPWOC was a cost-effective strategy for the treatment of complex wounds during ultrasonic debridement. For every two patients treated with HAPWOC, one complication was avoided.

Hypochlorous Acid Solution Is Safe for Intracavitary Lavage: Examination in a Rodent Model.

BACKGROUND: Intracavitary irrigation is a routine component of many surgical procedures, especially in those involving a contaminated field. Normal saline remains the irrigant of choice for most surgeons. Hypochlorous acid is a weak acid that produces hypochlorite ions with antimicrobial properties. Reducing microbial concentration during intracavitary irrigation is a potential benefit of using hypochlorous acid solution over normal saline. In this study, the safety of hypochlorous acid solution for intracavitary lavage was compared with normal saline in a rat model of 3 surgical procedures-laminectomy, thoracotomy, and laparotomy. METHODS: The intracavitary space was lavaged with either normal saline or hypochlorous acid. The procedures were also completed using Dakin's solution (sodium hypochlorite) as a comparator, given its known cytotoxicity. On postoperative day 5, necropsies of all animals were performed and relevant organs and blood samples obtained. Histology (hematoxylin and eosin staining) was used to examine biopsies of the collected organs for signs of inflammation, blood vessel integrity, and necrosis. Immunohistochemistry staining for caspase-3 was used to identify apoptotic cells. RESULTS: There were no differences in outcomes (survival, pain, and time to recovery) or histology between animals lavaged with hypochlorous acid and normal saline. Intact organ-specific architecture was observed in both groups. In comparison, rats treated with Dakin's solution demonstrated significant capsular fibrosis and hemorrhage. Furthermore, significant apoptosis was noted within the bowel mesentery of the group treated with Dakin's solution when stained for caspase-3. CONCLUSION: Hypochlorous acid is safe for lavage of intraperitoneal, intrathecal, and intrathoracic cavities. Further studies should be conducted to demonstrate efficacy of hypochlorous acid in an infected field.

In vitro microbicidal, anti-biofilm and cytotoxic effects of different commercial antiseptics.

Topical antiseptics are widely used for wound treatment, with the goal of disrupting biofilm capacity. We analysed the effectiveness of a variety of antiseptics to inhibit various stages of biofilm formation and to remove biofilms in vitro as well as the agents' cytotoxic effects on fibroblasts. We found that the chlorine-releasing agents exhibited immediate anti-biofilm effects in the short term, with lesser cytotoxicity than agents prepared from more stable compounds, such as biguanide or modified diallyl disulfide-oxide, which, conversely, have better long-term effectiveness. Among the examined organisms, Gram-positive bacteria and Candida albicans were the most sensitive to the antiseptics, whereas Pseudomonas aeruginosa and Acinetobacter baumannii were relatively resistant to them. Formulations whose mechanisms of action involve the release of chemically active chlorine were more effective when administered in solution than the gel form, likely because of the stability of the active ingredients during or after preparation of the formula. Interestingly, hypochlorous acid and some superoxidation solutions were effective in preventing biofilm formation within a short time period and showed virtually no toxicity. Our study indicates that most antiseptics remain effective long enough to prevent biofilm formation; thus, even brief application of an antiseptic agent during initial wound treatment can lead to better wound management outcomes.

The Immediate and Delayed Post-Debridement Effects on Tissue Bacterial Wound Counts of Hypochlorous Acid Versus Saline Irrigation in Chronic Wounds.

Introduction: Wound debridement is considered essential in chronic wound management. Hypochlorous acid has been shown to be an effective agent in reducing wound bacterial counts in open wounds. Ultrasound-enabled wound debridement is an effective and efficient method of debridement. This study compared ultrasound irrigation with hypochlorous acid versus saline irrigation for wound debridement on pre- and postoperative wounds and determined regrowth of bacteria over 1 week period of time. Finally, the outcome of definitive wound closure of the clinically clean-appearing wounds was recorded. Methods: Seventeen consenting adult patients with chronic open wounds were randomly selected for study. The patients were randomly divided into the hypochlorous acid irrigation or saline irrigation group. All patients provided pre- and postoperative tissue samples for qualitative and quantitative bacteriology. For the time (7 days) between the debridement procedure and the definitive closure procedure, the wounds were dressed with a silver-impregnated dressing and a hydroconductive dressing. Results: Both types of irrigation in the ultrasonic system initially lowered the bacterial counts by 4 to 6 logs. However, by the time of definitive closure, the saline-irrigated wounds had bacterial counts back up to 105 whereas the hypochlorous acid-irrigated wounds remained at 102 or fewer. More than 80% of patients in the saline group had postoperative closure failure compared with 25% of patients in the hypochlorous acid group. Conclusions: Hypochlorous acid irrigation with ultrasound debridement reduced bacterial growth in chronic open wounds more efficiently than saline alone. Postoperative wound closure outcomes suggest a remarkable reduction in wound complications after wound debridement using hypochlorous acid irrigation with ultrasound versus saline alone.

Primum non nocere: A therapeutic imperative for modern wound care.

This new paradigm revolves around meticulous wound bed preparation to allow the wound to proceed to endogenous healing or to set the stage for successful wound closure with autologous tissue.

Reduction of a multidrug-resistant pathogen and associated virulence factors in a burn wound infection model: further understanding of the effectiveness of a hydroconductive dressing.

OBJECTIVE: Drawtex's ability to remove pathogens and associated virulence factors has been demonstrated in vitro. A model of burn wound infection was used to characterize the in vivo impact of this dressing on infection and wound healing. METHODS: Paired burn wounds were created on the dorsum of Sprague Dawley rats and were inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Animals were divided into 2 groups, half with wounds that received experimental dressing and the remaining half with control dressing-treated wounds. Dressings remained in place through 3, 6, 9, or 14 days after injury, and methicillin-resistant S aureus and virulence factors were quantified. Laser Doppler imaging was used to examine wound perfusion, and local host immune response was assessed through the quantification of mRNA expression. RESULTS: By day 3, less methicillin-resistant S aureus was measured in wounds treated with experimental-dressing compared to control-dressing wounds. Quantities remained lower in the experimental group through day 14 (P < .001). More methicillin-resistant S aureus was quantified in the experimental dressing itself than in control dressing at all time points (P < .05). Experimental dressing-treated wounds contained less toxic shock syndrome toxin 1 and Panton-Valentine leukocidin than controls (P < .01) on days 6, 9, and 14. Induction of toll-like receptor 2, NOD-like receptor family, pyrin domain containing 3, and interleukin 6 was significantly lower in experimental-dressing treated wounds than in controls on days 6 and 9 (P < .05). CONCLUSIONS: The hydroconductive dressing provided a significant reduction in pathogen and virulence factors compared to a control dressing. As a result of clearance of virulence factors from the wound bed, a requisite alteration in host innate immune response was observed.

Obesity and surgical wound healing: a current review.

Objective. The correlation between obesity and deficient wound healing has long been established. This review examines the current literature on the mechanisms involved in obesity-related perioperative morbidity. Methods. A literature search was performed using Medline, PubMed, Cochrane Library, and Internet searches. Keywords used include obesity, wound healing, adipose healing, and bariatric and surgical complications. Results. Substantial evidence exists demonstrating that obesity is associated with a number of postoperative complications. Specifically in relation to wound healing, explanations include inherent anatomic features of adipose tissue, vascular insufficiencies, cellular and composition modifications, oxidative stress, alterations in immune mediators, and nutritional deficiencies. Most recently, advances made in the field of gene array have allowed researchers to determine a few plausible alterations and deficiencies in obese individuals that contribute to their increased risk of morbidity and mortality, especially wound complications. Conclusion. While the literature discusses how obesity may negatively affect health on various of medical fronts, there is yet to be a comprehensive study detailing all the mechanisms involved in obesity-related morbidities in their entirety. Improved knowledge and understanding of obesity-induced physiological, cellular, molecular, and chemical changes will facilitate better assessments of surgical risks and outcomes and create efficient treatment protocols for improved patient care of the obese patient population.

Comparative evaluation of silver-containing antimicrobial dressings on in vitro and in vivo processes of wound healing.

OBJECTIVES: To compare the in vitro and in vivo effects of silver products on wound healing. METHODS: Eight silver products were compared to determine: fibroblast function using fibroblast-populated collagen lattices (FPCLs), fibroblast viability using the Trypan Blue exclusion test, and fibroblast mitochondrial activity using the MTT [yellow tetrazolium salt; 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. In vivo effects of 9 silver products were evaluated utilizing a rat model of contaminated wounds. Serial quantitative bacteriology was performed on tissue biopsies over a 10-day period and serial wound areas were obtained over 12 days. RESULTS: Fibroblast cytotoxicity occurred for all of the silver products evaluated. Remaining viable fibroblasts were insufficient to allow FPCL contraction. Mitochondrial activity of the fibroblasts allowed a separation of the various silver compounds. Actisorb Silver and Silvercel had the greatest viable fibroblast activity, but less than the control. Despite in vitro cytotoxicity, all of the silver products except Contreet Foam and Acticoat Moisture Control accelerated wound healing. CONCLUSIONS: Silver-containing dressings appeared to benefit healing of the wounds. Just as in vitro bacterial analyses do not fully predict the effect of an antimicrobial in the in vivo setting, in vitro cytotoxicity tests do not fully predict the effect of an agent on wound healing trajectories. Because of the varied antimicrobial and wound healing responses among products, a careful consideration of the particular effects of individual silver-containing dressings or drugs is warranted.

Food and Drug Administration (FDA) drug approval end points for chronic cutaneous ulcer studies.

The rising costs of caring for chronic cutaneous ulcers (CCUs) and recent appreciation of the mortality of CCUs have led to consideration of the reasons for the failure to have new drug therapies. No new chemical entities to heal CCUs have been approved by the Food and Drug Administration (FDA) in over a decade, in part due to an inability to reach the FDA accepted end point of "complete wound closure." The frequent failure to reach the complete closure end point brings forward the question of the relevance of other healing end points such as improved quality of life, or partial healing. Because CCUs carry a prognosis and mortality rate worse than many cancers, it is reasonable to compare the FDA trial end points for cancer drug approval with those for CCUs. And the difference is quite striking. While there is only one end point for CCUs, there are five surrogate and three direct end points for cancers. In contrast to cancer, surrogate end points and partial healing are not acceptable for therapies aimed at CCUs. For example, making tumors smaller is an acceptable end point, but making CCUs smaller is not and improvement in the signs and symptoms of cancer is an acceptable end point for cancers but not CCUs. As CCUs carry a prognosis and mortality rate worse than many cancers, we believe a reconsideration of end points for CCUs is highly warranted.

The use of growth factors and other humoral agents to accelerate and enhance burn wound healing.

OBJECTIVE: Certain cytokines, especially those known as growth factors, have been demonstrated to mediate or modulate burn wound healing. Experimental and clinical evidence suggests that there are therapeutic advantages to the wound healing process when these agents are utilized. Positive effects have been reported for 4 types of wounds seen in the burn patient: partial-thickness wounds, full-thickness wounds, interstices of meshed skin grafts, and skin graft donor sites. METHODS: A comprehensive literature search was performed using the MEDLINE, Ovid, and Web of Science databases to identify pertinent articles regarding growth factors and other cytokines in burns and wound healing. RESULTS: The current knowledge about cytokine growth factors and their potential therapeutic applications in burn wound healing are discussed and reviewed. CONCLUSIONS: Platelet-derived growth factor, fibroblast growth factors, epidermal growth factors, transforming growth factor alpha, vascular endothelial growth factor, insulin-like growth factor I, nerve growth factor, transforming growth factor beta, granulocyte-macrophage colony-stimulating factor, and amnion-derived cellular cytokine solution have all been suggested to enhance the rate and quality of healing in 1 or more of these wounds encountered in burn care.

Amnion-derived cellular cytokine solution promotes macrophage activity.

Activated macrophages play a significant role in wound healing and infected tissue repair. In this study, we investigate the recruitment of macrophages into the wound, and the effects on the bactericidal/phagocyte activity after exposure to amnion-derived cellular cytokine solution (ACCS). To evaluate the influence of ACCS on the migratory behavior of macrophages, cell migration was assayed quantitatively using a Boyden chamber. Chemotactic migration activity of macrophages through the membrane determined the influence of ACCS. In the presence of ACCS, macrophages demonstrated a statistically significant (P < 0.05) increase in migration as compared with controls. Subsequently, groups of macrophages were exposed to different concentrations of ACCS solution. The killing and phagocytic activity of each group was compared with the control after exposure to Escherichia coli. Macrophage activity following activation by higher concentrations of ACCS demonstrated significantly increased phagocytosis as well as a trend correlation between percentage ACCS concentration and bactericidal activity. These cell types, critical to normal wound healing, may be influenced by ACCS to accelerate migration and enhance bactericidal/phagocytic activity in wounds.

Chemical characterization and biological properties of NVC-422, a novel, stable N-chlorotaurine analog.

During oxidative burst, neutrophils selectively generate HOCl to destroy invading microbial pathogens. Excess HOCl reacts with taurine, a semi-essential amino acid, resulting in the formation of the longer-lived biogenerated broad-spectrum antimicrobial agent, N-chlorotaurine (NCT). In the presence of an excess of HOCl or under moderately acidic conditions, NCT can be further chlorinated, or it can disproportionate to produce N,N-dichlorotaurine (NNDCT). In the present study, 2,2-dimethyltaurine was used to prepare a more stable N-chlorotaurine, namely, N,N-dichloro-2,2-dimethyltaurine (NVC-422). In addition, we report on the chemical characterization, in vitro antimicrobial properties, and cytotoxicity of this compound. NVC-422 was shown effectively to kill all 17 microbial strains tested, including antibiotic-resistant Staphylococcus aureus and Enterococcus faecium. The minimum bactericidal concentration of NVC-422 against Gram-negative and Gram-positive bacteria ranged from 0.12 to 4 µg/ml. The minimum fungicidal concentrations against Candida albicans and Candida glabrata were 32 and 16 µg/ml, respectively. NVC-422 has an in vitro cytotoxicity (50% cytotoxicity = 1,440 µg/ml) similar to that of NNDCT. Moreover, our data showed that this agent possesses rapid, pH-dependent antimicrobial activity. At pH 4, NVC-422 completely killed both Escherichia coli and S. aureus within 5 min at a concentration of 32 µg/ml. Finally, the effect of NVC-422 in the treatment of an E. coli-infected granulating wound rat model was evaluated. Treatment of the infected granulating wound with NVC-422 resulted in significant reduction of the bacterial tissue burden and faster wound healing compared to a saline-treated control. These findings suggest that NVC-422 could have potential application as a topical antimicrobial.

Clinical challenge: cutaneous Kaposi's sarcoma of the lower extremity.

Kaposi's sarcoma (KS) typically presents as multiple bilateral cutaneous patches or plaques of the lower extremities. This malignancy, however, can evolve with atypical presentation masquerading as a chronic wound. Lesions can mimic venous stasis ulcers, arterial insufficiency, vascular ulcers or chronic-infected wounds. With acquired immune deficiency syndrome (AIDS)-associated KS, lesions are even more widespread, and can affect the respiratory tract, lymph nodes, gastrointestinal tract, spleen, liver and, rarely, bone. As the initial diagnosis of KS is generally determined clinically, a high index of suspicion is necessary for all patients with a known or suspected history of HIV/AIDS. Tissue biopsy with histological analysis is essential for all wound types in this patient subset, regardless of wound presentation. The purpose of this report is to review the pathogenesis as well as the typical and atypical presentations of KS with an example of a diagnostic dilemma.

Impaired laparotomy wound healing in obese rats.

BACKGROUND: Obesity increases the risk of laparotomy dehiscence and incisional hernia. The aim of this study was to measure the biological effect of obesity on laparotomy wound healing and the formation of incisional hernias. METHODS: Normal-weight Sprague-Dawley (SD) and obese Zucker rats were used in an established laparotomy wound healing and incisional ventral hernia model. Mechanical testing was performed on abdominal wall strips collected from laparotomy wounds. Hernia size was measured by digital imaging. Picrosirius staining for collagen isoforms was observed with polarized microscopy. Abdominal wall fibroblasts were cultured to measure collagen matrix remodeling and proliferation. RESULTS: Laparotomy wound healing was significantly impaired in obese rats. Mechanical strength was lower than in normal-weight rats. Yield load was reduced in the obese group at all time points. Picrosirius red staining showed increased immature type III collagen content and disorganized type I collagen fibers within laparotomy wounds of obese rats. Wound size was significantly larger in the obese group. Collagen matrix remodeling was impaired with fibroblasts from obese rats, but there was no difference in fibroblast proliferation between the obese and normal-weight groups. CONCLUSIONS: We observed for the first time that laparotomy wound healing is impaired in obese rats. The recovery of laparotomy wound strength is delayed due to abnormal collagen maturation and remodeling, possibly due to a defect in fibroblast function. Strategies to improve outcomes for laparotomy wound healing in obese patients should include correcting the wound healing defect, possibly with growth factor or cell therapy.

Wound healing trajectories to determine pressure ulcer treatment efficacy.

BACKGROUND: Wound healing trajectories (percent healing vs time) provide a dynamic picture of the decrease in wound burden over the entire continuum of the healing process. Trajectories can be robustly compared using survival statistics methodology. Improvement in healing can be determined by shifting the curve from "impaired" healing toward "ideal" healing. Although this concept of shifting the curve "to the left" has been demonstrated in acute incisional healing depicted by the gain in tensile strength, and in other chronic wounds, it has not been utilized for chronic pressure ulcers. METHODS: Wound healing trajectories were constructed for 211 patients enrolled in 8 separate randomized clinical trials for grade III and IV pressure ulcers. Trajectories were constructed for patients achieving ≥90% or more healing within 112 days and those who achieved less than <90% wound closure. Kaplan-Meier curves were constructed for all patients receiving an experimental treatment and for those receiving placebo vehicles. RESULTS: Different trajectories were achieved for the faster healing patients. Eighty-one percent of patients reached 90% healing within 112 days; 80% of those in treatment groups and 85% of those in placebo groups. Linear regression suggested that all patients entered into the clinical trials would achieve 90% healing by 18 weeks. Only 17% of the patients achieved total healing (100% wound closure) within the 112-day study period. Linear regression suggested that it would take 110 weeks to achieve total healing in all patients. CONCLUSION: Wound healing trajectories provide a more complete description of treatment efficacy than do fixed endpoints, such as the number of patients achieving 100% closure at one defined time point. Since more successful healers have different trajectories than less successful healers, shifting the trajectory to the left from "impaired" toward "ideal" healing may provide a better endpoint to determine treatment efficacy.

Individualized, targeted wound treatment based on the tissue bacterial level as a biological marker.

BACKGROUND: The use of biologic markers to aid in individualizing wound treatment may help improve outcomes. A biologic marker that has been demonstrated to be predictive of healing in both chronic and acute wounds is wound tissue bacterial level. The objective of this study was to determine whether tissue bacterial level can be used to individualize wound treatment regimens with a stem-like cell-derived product. METHODS: Amnion-derived cellular cytokine solution (ACCS) was topically applied to rat chronic wounds, and healing rates were measured. RESULTS: Experimental wounds treated with ACCS demonstrated accelerated healing regardless of the tissue level of bacteria, compared with saline. As the level of tissue bacteria increased, the frequency of ACCS application required to obtain optimal results increased. CONCLUSIONS: It appears that the biologic characteristic of tissue bacterial level can serve as a marker to predict the response of open granulating wounds treated with ACCS.

Amnion-derived cellular cytokine solution (ACCS) promotes migration of keratinocytes and fibroblasts.

Amnion-derived Multipotent Progenitor cells appear to be useful as adjuvants in wound healing. Amnion-derived multipotent progenitor cells secrete a unique combination of cytokines and growth factors, known as amnion-derived cellular cytokine solution (ACCS). In the skin, a cytokine communication network between mesenchymal and epithelial cells tightly controls keratinocyte and fibroblast migration, proliferation and differentiation-key determinants of wound healing. To evaluate the influence of ACCS on the migratory behavior of keratinocytes and fibroblasts, cell migration was assayed quantitatively using a Boyden chamber. Chemotactic migration activity of fibroblasts or keratinocytes through the membrane determined the influence of ACCS. In the presence of ACCS, fibroblasts and keratinocytes demonstrated a statistically significant (P < 0.05) increase in migration when compared with controls. These cell types, critical to normal wound healing, may be influenced to accelerate migration in wounds, thus accelerating wound repair/healing.

Effect of amnion-derived cellular cytokine solution on healing of experimental partial-thickness burns.

BACKGROUND: Amnion-derived multipotent progenitor (AMP) cells, unlike most stem cells, have been demonstrated to be nontumorigenic and nonimmunogenic. Amnion-derived cellular cytokine solution (ACCS), a secreted product of AMP cells, is a cocktail of cytokines existing at physiological levels and has been used to accelerate epithelialization of experimental partial-thickness burns. METHODS: Using modifications of Zawacki's guinea pig partial-thickness scald burn model, a total of 65 animals were treated with ACCS, ACCS + AMP cells, unconditioned medium (UCM) + AMP cells, or either UCM alone or saline as controls. Dosage times ranged from every other day to once a week. Percent epithelialization was serially determined from acetate wound tracings. Histology was performed on wound biopsies. RESULTS: ACCS, UCM + AMP cells, and ACCS + AMP cells improved epithelialization compared with the two control groups (P < 0.05). When ACCS was delivered more frequently, statistically significant more rapid epithelialization occurred (P < 0.05). By day 7, all groups treated with ACCS had reached at least 90% epithelialization, whereas control groups were only 20-40% epithelialized (P < 0.05). Histology showed excellent regeneration of the epidermis with rete ridge formation. Hair growth occurred in ACCS-treated animals but not in the control group. CONCLUSIONS: Amnion-derived cellular cytokine solution accelerates the healing of experimental partial-thickness burns. Based on these findings, a multicenter clinical trial is underway.

The effect of amnion-derived cellular cytokine solution on the epithelialization of partial-thickness donor site wounds in normal and streptozotocin-induced diabetic swine.

OBJECTIVE: The purpose of this study was to determine whether amnion-derived cellular cytokine solution (ACCS) could improve the quality of epithelialization and accelerate closure of dermatome-created partial-thickness wounds in normal and streptozotocin-induced diabetic pigs. METHODS: Dermatome-created partial-thickness wounds were sealed with wound chambers in healthy and diabetic pigs and were injected with ACCS. Wound fluid was exchanged daily for total protein concentration, and biopsies were taken on days 6, 8, 10, and 12. Epithelialization, thickness of epidermis, number of epidermal cell layers, and rete ridges were evaluated. RESULTS: The macroscopic appearance of the wounds and speed of healing was similar in all groups at each time point. All wounds were healed by day 6. The epidermis was thicker in the ACCS-treated diabetic wounds than in the controls (140.6 microm vs 82.7 microm on day 12 in diabetic pigs). There were more cell layers (13 vs 7.7) in ACCS-treated diabetic pigs on day 12. The number of rete ridges per 2.5 mm was greater on day 12 in the ACCS-treated diabetic wounds (13 vs 8). There was also a significant increase in the number of rete ridges in ACCS-treated nondiabetic pigs but no difference in epidermal thickness or number of cell layers. CONCLUSION: In diabetic pigs, we found a significantly thicker epidermis and more cell layers and rete ridges in the ACCS-treated wounds. Healthy pigs showed more rete ridges but no difference in thickness of epidermis or number of cell layers on day 12.