Best-practice algorithms for the use of a bilayered living cell therapy (ApligrafR) in the treatment of lower-extremity ulcers

A bioengineered living cell construct activates an acute wound healing response in venous leg ulcers

Chronic nonhealing venous leg ulcers (VLUs) are widespread and debilitating, with high morbidity and associated costs; about $15 billion is spent annually on the care of VLUs in the United States. Despite this, there is a paucity of treatments for VLUs because of the lack of pathophysiologic insight into ulcer development as well as the lack of knowledge regarding biologic actions of existing VLU-targeted therapies. The bioengineered bilayered living cellular construct (BLCC) skin substitute is a U.S. Food and Drug Administration-approved biologic treatment for healing VLUs. To elucidate the mechanisms through which the BLCC promotes healing of chronic VLUs, we conducted a clinical trial (NCT01327937) in which patients with nonhealing VLUs were treated with either standard of care (compression therapy) or the BLCC together with standard of care. Tissue was collected from the VLU edge before and 1 week after treatment, and the samples underwent comprehensive microarray mRNA and protein analyses. Ulcers treated with the BLCC skin substitute displayed three distinct transcriptomic patterns, suggesting that BLCC induced a shift from a nonhealing to a healing tissue response, involving modulation of inflammatory and growth factor signaling, keratinocyte activation, and attenuation of Wnt/β-catenin signaling. In these ways, BLCC application orchestrated a shift from the chronic nonhealing ulcer microenvironment to a distinctive healing milieu resembling that of an acute, healing wound. Our findings provide in vivo evidence in VLU patients of pathways that can be targeted in the design of new therapies to promote healing of chronic VLUs.

Disabling Pansclerotic Morphea of Childhood Poses a High Risk of Chronic Ulceration of the Skin and Squamous Cell Carcinoma

Disabling pansclerotic morphea of childhood (DPMC) is a rare and severe variant of scleroderma. This report presents 3 cases that presented to the authors and studies 25 patients from the literature (English language only) for the presence of chronic nonhealing ulcers of skin and skin cancer. The authors identified a total of 30 patients (9 male and 21 female) aged between 1 and 37 years at time of presentation. All cases were less than 14 years old when the disease started. The majority of patients had an aggressive course with deep sclerotic lesions leading to joint contractures and immobility. Five patients suffered from chronic nonhealing leg ulcers (17%), but ulcers were present on other parts of the body (upper limbs, trunk, head) as well (n = 6). Four patients died because of complications of the disease such as sepsis or gangrene. Two patients developed a squamous cell carcinoma at the age of 16 years and 19 years, respectively (6.7%). The available treatment of DMPC-associated ulcers is unsatisfying. Only temporary improvements have been seen in a minority of patients. We report on marked improvement of chronic leg ulcers by a combination of sildenafil 3 × 20 mg/day and repeated application of a porcine small intestinal submucosal acellular matrix.

Cost-effectiveness of three adjunct cellular/tissue-derived products used in the management of chronic venous leg ulcers

OBJECTIVES

Determine the cost-effectiveness of three topically applied cellular/tissue-derived products (CTPs) used as adjunct therapies to standard care in the management of venous leg ulcers (VLUs).

METHODS

A three-state Markov model derived from the medical literature was developed to estimate the comparative cost-effectiveness of three CTPs in relation to VLU standard care. CTPs evaluated in the study included extracellular matrix (ECM), human skin equivalent (HSE), and living skin equivalent (LSE). The three Markov states included unhealed, healed, and death. A 1-year time horizon was used to determine the number of ulcer-free weeks and the expected costs of therapies. The payer perspective was taken in the analysis and only the direct costs of care were considered. Sensitivity analyses were performed to gauge model parameter uncertainty.

RESULTS

The expected costs for standard care, ECM, HSE, and LSE VLU therapy were $6,132, $6,732, $10,638, and $11,237, while the expected outcomes were 24, 31, 29, and 27 ulcer-free weeks, respectively. ECM was economically dominant among the three CTPs. In the base case of ECM versus standard care, the incremental cost-effectiveness ratio for ECM therapy was $86 per ulcer-free week. Sensitivity analysis did not alter ECM dominance. Clinic visits and home health utilization exhibited the greatest influence on cost.

CONCLUSIONS

ECM is the most cost-effective CTP when used in the management of VLUs as an adjunct to standard care. These findings suggest that VLU standard care therapy with ECM can yield potential cost savings and produce better outcomes than do other CTPs.

The use of skin substitutes in the treatment of the hand and upper extremity

The introduction of skin substitutes in the last decade has dramatically changed how we think about the concept of "non-healing" wounds. Their use has improved prognosis and reduced morbidity in the treatment of open wounds. This article aims to summarize the development of tissue-engineered skin substitutes, discuss their use, and highlight some specific applications in different clinical settings.

Comparative effectiveness of a bilayered living cellular construct and a porcine collagen wound dressing in the treatment of venous leg ulcers

Using data from a national wound-specific electronic medical record (WoundExpert, Net Health, Pittsburgh, PA), we compared the effectiveness of a bilayered living cellular construct (BLCC) and an acellular porcine small intestine submucosa collagen dressing (SIS) for the treatment of venous leg ulcer. Data from 1,489 patients with 1,801 refractory venous leg ulcers (as defined by failure to have >40% reduction in size in the 4 weeks prior to treatment) with surface areas between 1 and 150 cm(2) in size, treated between July 2009 and July 2012 at 158 wound care facilities across the US were analyzed. Patient baseline demographics and wound characteristics were comparable between groups. Kaplan-Meier-derived estimates of wound closure for BLCC (1,451 wounds) was significantly greater (p = 0.01, log-rank test) by weeks 12 (31% vs. 26%), 24 (50% vs. 41%), and 36 (61% vs. 46%), respectively, compared with SIS (350 wounds). BLCC treatment reduced the median time to wound closure by 44%, achieving healing 19 weeks sooner (24 vs. 43 weeks, p = 0.01, log-rank test). Treatment with BLCC increased the probability of healing by 29% compared with porcine SIS dressing (hazard ratio = 1.29 [95% confidence interval 1.06, 1.56], p = 0.01).

Novel collagen/gelatin scaffold with sustained release of basic fibroblast growth factor: clinical trial for chronic skin ulcers

Chronic skin ulcers such as diabetic ulcers and venous leg ulcers are increasing and are a costly problem in healthcare. We have developed a novel artificial dermis, collagen/gelatin sponge (CGS), which is capable of sustained release of basic fibroblast growth factor (bFGF) for more than 10 days. The objective of this study was to investigate the safety and efficacy of CGS impregnated with bFGF in the treatment of chronic skin ulcers. Patients with chronic skin ulcers that had not healed in at least 4 weeks were treated with CGS impregnated with bFGF at 7 or 14 μg/cm(2) after debridement, and the wound bed improvement was assessed 14 days after application. Wound bed improvement was defined as a granulated and epithelialized area on day 14 with a proportion to the baseline wound area after debridement of 50% or higher. The wound area, the wound area on day 14, and the granulation area on day 14 were independently measured by blinded reviewers in a central review using digital images of wounds taken with a calibrator. Patients were followed up until 28 days after application to observe the adverse reactions related to the application of CGS. From May 2010 to June 2011, 17 patients were enrolled and, in 16 patients, the wound bed improved. Among the randomized patients in step 2, no significant difference was seen between the low-dose group and the high-dose group. No serious adverse reactions were observed. Adverse reactions with a clear causal relationship to the study treatment were mild and patients quickly recovered from them. This study is the first-in-man clinical trial of CGS and showed the safety and efficacy of CGS impregnated with bFGF in the treatment of chronic skin ulcers. This combination therapy could be a promising therapy for chronic skin ulcers.

An exploratory clinical study on the safety and efficacy of an autologous fibroblast-seeded artificial skin cultured with animal product-free medium in patients with diabetic foot ulcers

Cultured dermal substitutes have been used for the treatment of chronic skin ulcers; however, the biological risks of animal-derived materials in the culture process such as foetal bovine serum (FBS) have been reported. In this study, we prepared an autologous fibroblast-seeded artificial dermis (AFD) using animal-product-free medium supplemented with 2% patient autologous serum and without any animal-derived materials such as trypsin in the culturing process. We applied the AFD in five patients with diabetic ulcers and investigated its safety and efficacy. As the primary endpoint, we defined 'wound bed improvement' according to the percentage of granulation area to the whole wound area on day 21, and 60% or higher was regarded as improved. The mean age of the patients was 60·6 years and the mean duration of the ulcer was 22·6 months. In the evaluation of the primary endpoint, the 'wound bed' was improved in all patients [proportion of improvement: 100%, 95% confidence interval (CI): 48% to 100%]. Three patients had complete wound healing within 12 weeks after application and two patients had >80% wound healing at 12 weeks. Side effects were not serious. Our AFD may be a safe and effective treatment of diabetic ulcers.

Correction of Hypoxia, a Critical Element for Wound Bed Preparation Guidelines: TIMEO2 Principle of Wound Bed Preparation

Wound bed preparation is an organized approach to create an optimal environment for wound healing by the use of the most cost-effective therapeutic options. It has become an essential part of wound management and seeks to use the latest findings from molecular and cellular research to maximize the benefits of today's advanced wound care products. The international advisory panel on wound bed preparation met in 2002 to develop a systemic approach to wound management. These principles of this approach are referred to by the mnemonic TIME, which stands for the management of nonviable or deficient tissue (T), infection or inflammation (I), prolonged moisture imbalance (M), and nonadvancing or undermined epidermal edge (E). One critical element of pathophysiology, understanding of the hypoxic nature of the wound and correction of hypoxia as a critical element of wound bed preparation, is not covered. This article proposes to add correction of hypoxia to the TIME principle (TIMEO2 principle) based on the evidence. The evidence that will support the reason and the need for modification of the wound bed preparation protocol is discussed.

Preclinical study of an ex vivo gene therapy protocol for hepatocarcinoma

Preclinical studies in several animal models as well as clinical trials have shown a reduction in tumor growth following immunotherapy with interleukin-12 (IL-12). This cytokine is appropriate to test in therapeutic clinical trials to treat hepatocarcinoma (HC), a pathology often associated with hepatitis B or C-induced cirrhosis. The local delivery into the liver would be achieved through ex vivo gene transfer using retroviral (rv) vectors in autologous fibroblast carriers. In support of this clinical trial, a rv vector has been constructed to express coordinately both chains p35 and p40 of human IL-12. Here, we have tested good manufacturing practices (GMP) clinical lots of viral vectors derived from the transfected packaging cell line, PG13rvIL-12. We have also devised methods to facilitate the isolation of fibroblasts from freshly harvested skin specimens, enhance their outgrowth in large-scale cultures and assay IL-12 production following transduction, without any selection and irradiation. Twenty-four human skin specimens were processed to obtain fibroblast suspensions that were typically maintained for up to 8 or 12 passages. The mean +/-s.d. overall time for obtaining the required number of transduced cells for the highest IL-12 need was 40 days. The procedure, in accordance with the French medical agency for gene therapy clinical trials, is now ready to begin a clinical trial.

Randomized, controlled, single-blind study on use of autologous keratinocytes on a transfer dressing to treat nonhealing diabetic ulcers

AIM

To compare the rate of healing of diabetic neuropathic ulcers using cultured autologous keratinocytes delivered on chemically defined transfer discs (Myskin) (active treatment) versus healing obtained with cell-free discs (placebo).

MATERIALS AND METHODS

After a 4-week lead-in period patients (randomly assigned) received active or placebo treatments weekly for 6 weeks. All patients then received active treatments for a maximum of 12 treatments where required. Altogether, 16 patients with a total of 21 ulcers resistant to conventional therapy were recruited from four specialist diabetic centers in three cities.

RESULTS

All 21 ulcers were treated and of these ten healed and eight improved, with two failing to respond (one ulcer was lost due to autoamputation). For analysis according to the study criteria, however, only the 12 patients with 12 index ulcers who completed treatment protocols were eligible - five in the placebo group and seven in the active group. Of these, five ulcers healed completely and seven were reduced by more than 50%. Complete healing took a median of ten active applications.

CONCLUSIONS

Repeated regular applications of the patient's keratinocytes, delivered on the carrier dressing, initiated wound healing in ulcers resistant to conventional therapy, with 18 out of 21 ulcers responding. The healing observed did not appear attributable to patient recruitment or the cell-free carrier dressing but to the delivery of the cultured cells.

A review of a bi-layered living cell treatment (Apligraf) in the treatment of venous leg ulcers and diabetic foot ulcers

Apligraf^® (Organogenesis, Canton, MA) is a bi-layered bioengineered skin substitute and was the first engineered skin US Food and Drug Administration (FDA)-approved to promote the healing of ulcers that have failed standard wound care. Constructed by culturing human foreskin-derived neonatal fibroblasts in a bovine type I collagen matrix over which human foreskin-derived neonatal epidermal keratinocytes are then cultured and allowed to stratify, Apligraf provides both cells and matrix for the nonhealing wound. Its exact mechanism of action is not known, but it is known to produce cytokines and growth factors similar to healthy human skin. Initially approved by the FDA in 1998 for the treatment of venous ulcers greater than one-month duration that have not adequately responded to conventional therapy, Apligraf later received approval in 2000 for treatment of diabetic foot ulcers of greater than three weeks duration. Herein, we review the use of Apligraf in the treatment of chronic venous leg ulcers and diabetic foot ulcers. Our goal is to provide a working understanding of appropriate patient selection and proper use of the product for any physician treating this segment of the aging population.