Effects of immunoregulatory cytokines on the immunogenic potential of the cellular components of a bilayered living skin equivalent

Clinical Evaluation of NIKS-Based Bioengineered Skin Substitute Tissue in Complex Skin Defects: Phase I/IIa Clinical Trial Results

BACKGROUND

Complex skin defects, such as burns and acute cutaneous trauma, are life-threatening injuries, often requiring temporary allograft placement to maintain fluid homeostasis and prevent infection until permanent wound closure is possible.

THE PROBLEM

The current standard of care for the management of full-thickness wounds that are unable to be closed in a single surgical stage is temporary coverage with cadaver allograft until an acceptable wound bed has been established. This approach has limitations including limited availability of human cadaver skin, the risk of disease transmission from cadaveric grafts, and inconsistent cadaver allograft quality.

BASIC/CLINICAL SCIENCE

Near-diploid neonatal human keratinocyte cell line (NIKS)-based human skin tissue is a full-thickness, living human skin substitute composed of a dermal analog containing normal human dermal fibroblasts and a fully-stratified, biologically and metabolically active epidermis generated from NIKS keratinocytes, a consistent and unlimited source of pathogen-free human epidermal progenitor cells.

CLINICAL CARE RELEVANCE

NIKS-based human skin tissue is a living bioengineered skin substitute (BSS) intended to provide immediate wound coverage and promote wound healing through sustained expression by living cells of wound healing factors.

CONCLUSION

A phase I/IIa clinical trial found that NIKS-based BSS was well tolerated and comparable to cadaver allograft in the ability to prepare full-thickness complex skin defects prior to autografting. There were no deaths and no adverse events (AE) associated with this BSS. Exposure of the study subjects to the skin substitute tissue did not elicit detectable immune responses. Notably, this tissue remained viable and adherent in the wound bed for at least 7 days.

StrataGraft skin substitute is well-tolerated and is not acutely immunogenic in patients with traumatic wounds: results from a prospective, randomized, controlled dose escalation trial

OBJECTIVE

The goal of this study was to assess the immunogenicity and antigenicity of StrataGraft skin tissue in a randomized phase I/II clinical trial for the temporary management of full-thickness skin loss.

BACKGROUND

StrataGraft skin tissue consists of a dermal equivalent containing human dermal fibroblasts and a fully stratified, biologically active epidermis derived from Near-diploid Immortalized Keratinocyte S (NIKS) cells, a pathogen-free, long-lived, consistent, human keratinocyte progenitor.

METHODS

Traumatic skin wounds often require temporary allograft coverage to stabilize the wound bed until autografting is possible. StrataGraft and cadaveric allograft were placed side by side on 15 patients with full-thickness skin defects for 1 week before autografting. Allografts were removed from the wound bed and examined for allogeneic immune responses. Immunohistochemistry and indirect immunofluorescence were used to assess tissue structure and cellular composition of allografts. In vitro lymphocyte proliferation assays, chromium-release assays, and development of antibodies were used to examine allogeneic responses.

RESULTS

One week after patient exposure to allografts, there were no differences in the numbers of T or B lymphocytes or Langerhans cells present in StrataGraft skin substitute compared to cadaver allograft, the standard of care. Importantly, exposure to StrataGraft skin substitute did not induce the proliferation of patient peripheral blood mononuclear cells to NIKS keratinocytes or enhance cell-mediated lysis of NIKS keratinocytes in vitro. Similarly, no evidence of antibody generation targeted to the NIKS keratinocytes was seen.

CONCLUSIONS

These findings indicate that StrataGraft tissue is well-tolerated and not acutely immunogenic in patients with traumatic skin wounds. Notably, exposure to StrataGraft did not increase patient sensitivity toward or elicit immune responses against the NIKS keratinocytes. We envision that this novel skin tissue technology will be widely used to facilitate the healing of traumatic cutaneous wounds.This study was registered at www.clinicaltrials.gov (NCT00618839).