Complete wound closure following a single topical application of a novel autologous homologous skin construct: first evaluation in an open-label, single-arm feasibility study in diabetic foot ulcers

A multicenter, randomized controlled clinical trial evaluating the effects of a novel autologous heterogeneous skin construct in the treatment of Wagner one diabetic foot ulcers: Final analysis

A novel autologous heterogeneous skin construct (AHSC) was previously shown to be effective versus standard of care (SOC) treatment in facilitating complete wound healing of Wagner 1 diabetic foot ulcers in an interim analysis of 50 patients previously published. We now report the final analysis of 100 patients (50 per group), which further supports the interim analysis findings. Forty-five subjects in the AHSC treatment group received only one application of the autologous heterogeneous skin construct, and five received two applications. For the primary endpoint at 12 weeks, there were significantly more diabetic wounds closed in the AHSC treatment group (35/50, 70%) than in the SOC control group (17/50, 34%) (p = 0.00032). A significant difference in percentage area reduction between groups was also demonstrated over 8 weeks (p = 0.009). Forty-nine subjects experienced 148 adverse events: 66 occurred in 21 subjects (42%) in the AHSC treatment group versus 82 in 28 SOC control group subjects (56.0%). Eight subjects were withdrawn due to serious adverse events. Autologous heterogeneous skin construct was shown to be an effective adjunctive therapy for healing Wagner 1 diabetic foot ulcers.

Innovations in Stem Cell Therapy for Diabetic Wound Healing

Significance: The global burden of diabetic wounds, particularly diabetic foot ulcers, continues to have large economic and social impact throughout the world. Current strategies are not sufficient to overcome this burden of disease. Finding newer, more advanced regenerative cell and tissue-based strategies to reduce morbidity remains paramount. Recent Advances: Recent advances in stem cell therapies are discussed. We also highlight the practical issues of translating these advancing technologies into the clinical setting. Critical Issues: We discuss the use of somatic and induced pluripotent stem cells and the stromal vascular fraction, as well as innovations, including the use of 3D bioprinting of skin. We also explore related issues of using regenerative techniques in clinical practice, including the current regulatory landscape and translatability of in vivo research. Future Directions: Advances in stem cell manipulation showcase the best therapeutic resources available to enhance mechanisms of wound healing such as angiogenesis, cell proliferation, and collagen synthesis; potential methods include changing the scaffold microenvironment, including relative oxygen tension, and the use of gene modification and nanotechnology. Secretome engineering, particularly the use of extracellular vesicles, may be another potential cell-derived therapeutic that may enable use of cell-free translational therapy.

Evaluation in a porcine wound model and long-term clinical assessment of an autologous heterogeneous skin construct used to close full-thickness wounds

Acute and chronic wounds involving deeper layers of the skin are often not adequately healed by dressings alone and require therapies such as skin grafting, skin substitutes, or growth factors. Here we report the development of an autologous heterogeneous skin construct (AHSC) that aids wound closure. AHSC is manufactured from a piece of healthy full-thickness skin. The manufacturing process creates multicellular segments, which contain endogenous skin cell populations present within hair follicles. These segments are physically optimized for engraftment within the wound bed. The ability of AHSC to facilitate closure of full thickness wounds of the skin was evaluated in a swine model and clinically in 4 patients with wounds of different etiologies. Transcriptional analysis demonstrated high concordance of gene expression between AHSC and native tissues for extracellular matrix and stem cell gene expression panels. Swine wounds demonstrated complete wound epithelialization and mature stable skin by 4 months, with hair follicle development in AHSC-treated wounds evident by 15 weeks. Biomechanical, histomorphological, and compositional analysis of the resultant swine and human skin wound biopsies demonstrated the presence of epidermal and dermal architecture with follicular and glandular structures that are similar to native skin. These data suggest that treatment with AHSC can facilitate wound closure.

Tissue Engineering-Based Strategies for Diabetic Foot Ulcer Management

Significance: Diabetic foot ulcers (DFU) are a mounting problem with the increasingly frail population. Injuries that would otherwise heal are kept open by risk factors such as diabetes, obesity, and age-related conditions, which interferes with the natural wound healing processes. Recent Advances: This review summarizes recent advancements in the field of tissue engineering for the treatment of DFUs. FDA-approved approaches, including signaling-based therapies, stem cell therapies, and skin substitutes are summarized and cutting-edge experimental technologies that have the potential to manage chronic wounds, such as skin printing, skin organogenesis, skin self-assembly, and prevascularization, are discussed. Critical Issues: The standard of care for chronic wounds involves wound debridement, wound dressings, and resolving the underlying cause such as lowering the glycemic index and reducing wound pressure. Current DFU treatments are limited by low wound closure rates and poor regrown skin quality. New adjuvant therapies that facilitate wound closure in place of or in conjunction with standard care are critically needed. Future Directions: Tissue engineering strategies are limited by the plasticity of adult human cells. In addition to traditional techniques, genetic modification, although currently an emerging technology, has the potential to unlock human regeneration and can be incorporated in future therapeutics.

Autologous Heterogeneous Skin Construct Closes Traumatic Lower Extremity Wounds in Pediatric Patients: A Retrospective Case Series

Lower extremity traumatic wounds pose unique challenges in pediatric patients, including vessel caliber, compliance with postoperative instructions, parental concerns about multiple operations, and long-term function. An autologous heterogeneous skin construct (AHSC) has demonstrated the ability to cover avascular structures and regenerate full-thickness functional skin. The objective of this study is to report our experience using AHSC in a cohort of pediatric trauma patients. This study is a noncontrolled, retrospective cohort analysis of all pediatric patients (<19 years of age) treated with AHSC for lower extremity traumatic wounds with at least one exposed deep structure (tendon, bone, and/or joint) at a single institution between May 1, 2018, and April 1, 2019. Seven patients with 10 traumatic wounds met inclusion criteria. The median follow-up time was 11.8 months. Five patients were male (71%); the median age was 7 years (range = 2-15 years). Average wound size was 105 cm². All wounds achieved coverage of exposed structures and epithelial closure in a median of 13 and 69 days, respectively. There were no donor site complications and no reoperations required. All patients returned to normal activity, ambulate without limp, can wear shoes normally, and have normal tendon gliding. AHSC covered exposed structures and achieved closure within a single application in complex traumatic lower extremity wounds in a pediatric cohort.

A multicentre, randomised controlled clinical trial evaluating the effects of a novel autologous, heterogeneous skin construct in the treatment of Wagner one diabetic foot ulcers: Interim analysis

We desired to carefully evaluate a novel autologous heterogeneous skin construct in a prospective randomised clinical trial comparing this to a standard-of-care treatment in diabetic foot ulcers (DFUs). This study reports the interim analysis after the first half of the subjects have been analysed. Fifty patients (25 per group) with Wagner 1 ulcers were enrolled at 13 wound centres in the United States. Twenty-three subjects underwent the autologous heterogeneous skin construct harvest and application procedure once; two subjects required two applications due to loss of the first application. The primary endpoint was the proportion of wounds closed at 12 weeks. There were significantly more wounds closed in the treatment group (18/25; 72%) vs controls (8/25; 32%) at 12 weeks. The treatment group achieved significantly greater percent area reduction compared to the control group at every prespecified timepoint of 4, 6, 8, and 12 weeks. Thirty-eight adverse events occurred in 11 subjects (44%) in the treatment group vs 48 in 14 controls (56%), 6 of which required study removal. In the treatment group, there were no serious adverse events related to the index ulcer. Two adverse events (index ulcer cellulitis and bleeding) were possibly related to the autologous heterogeneous skin construct. Data from this planned interim analysis support that application of autologous heterogeneous skin construct may be potentially effective therapy for DFUs and provide supportive data to complete the planned study.

A Prospective, Multicenter, Pilot Trial Of A Novel Homologous Skin Construct On Deep Partial-Thickness And Full-Thickness Burns

Split-thickness skin grafting (STSG) is the standard of care for treating deep burns. They often contract, have unpredictable cosmetic outcomes, lack dermal appendages, and result in painful, conspicuous donor sites. An autologous homologous skin construct (AHSC) has been shown to produce full-thickness skin architecture. This study examined the safety profile, engraftment, and quality of healing of a pilot group of AHSC-treated burn wounds. Following IRB approval and informed consent, patients with deep-partial/full-thickness burns requiring grafting underwent side-by-side treatment with AHSC and STSG. A 2 cm2 fullthickness harvest was processed into AHSC at an FDA-registered facility, returned within 48 hours, and applied to a 4 cm2 area alongside a STSG. AHSC donor site was closed primarily. Wounds were evaluated for healing with digital photography and investigator assessments for 90 days. All adverse events (AEs) were recorded. Eight patients with average 13.3% TBSA [range 2-58%] burn wounds were treated: 5 Caucasian and 3 African American with an average body mass index (BMI) of 26.8. Injury was due to predominantly flame burn, with additional injury from grease, scald, contact, friction and flash. Mean time between injury and AHSC treatment was 11 days [range 5-35 days]. All patients had adequate engraftment and complete epithelialization by the end of the study. Patients required one application of AHSC and no other additional surgical procedures at the application sites. The most common AEs for STSG-treated wounds included hypertrophic scarring and pruritus. One non-infected AHSC harvest site experienced a dehiscence. There were no other AEs related to AHSC treatment. AHSC treatment is feasible in deep partial and fullthickness burn wounds warranting additional investigation.

Complete wound closure following a single topical application of a novel autologous homologous skin construct: first evaluation in an open-label, single-arm feasibility study in diabetic foot ulcers

Diabetic foot ulcers (DFUs) are a growing burden on patients and health care systems that often require multiple treatments of both conventional and advanced modalities to achieve complete wound closure. A novel autologous homologous skin construct (AHSC) has been developed to treat cutaneous defects with a single topical application, by leveraging the endogenous repair capabilities of the patient's healthy skin. The AHSC's ability to close DFUs with a single treatment was evaluated in an open-label, single-arm feasibility study. Eleven patients with DFUs extending up to tendon, bone, or capsule received a single topical application of AHSC. Closure was documented weekly with high-resolution digital photography and wound planimetry. All 11 DFUs demonstrated successful graft take. Ten DFUs closed within 8 weeks. The median time-to-complete closure was 25 days. The mean percent area reduction for all 11 wounds at 4 weeks was 83%. There were no adverse events related to the AHSC treatment site. This pilot study demonstrated AHSC may be a viable single application topical intervention for DFUs and warrants investigation in larger, controlled studies.