Implications for Faster Healing with Fewer Applications: Sustained Graft Persistence and Favorable Wound-Healing Biology of a Proprietary Processed Placental Tissue Allograft

Abstract

Introduction Placental tissue allografts are widely utilized as wound coverings and barriers. In addition to tissue source, manufacturing and processing methodologies can influence extracellular matrix (ECM) architecture, mechanical stability, protease susceptibility, degradation kinetics, and graft persistence following implantation. An optimized placental tissue allograft should maintain sufficient matrix integrity during the active period of tissue repair while preserving the biological characteristics associated with a favorable wound healing environment. Our previously published work demonstrated that a proprietary processed human amniotic membrane allograft exhibited a more favorable wound healing biologic profile than conventionally processed placental tissue. The finding that no XWRAP treated wound had reached the reapplication threshold at Day 14, considered together with previously demonstrated favorable wound healing biology, provides a mechanistic rationale for the hypothesis that XWRAP may support faster healing with fewer applications over a course of wound management. Methods Graft integrity was evaluated every 2 days for 14 days following application to standardized full thickness excisional wounds in Sprague Dawley rats. XWRAP, a proprietary processed human amniotic membrane allograft, was compared with a donor matched conventionally processed human amniotic membrane comparator and a commercial placental tissue comparator. Graft integrity was scored from 0 to 5, where 0 represented complete graft loss or resorption and 5 represented an intact graft. A score [&le;]1 represented the protocol defined threshold for reapplication during non terminal visits. Longitudinal graft integrity trajectories, original graft degradation, documented reapplications, and the proportion of wounds reaching the reapplication threshold were evaluated. At each visit, graft integrity in XWRAP treated wounds was compared with the pooled comparator groups (primary comparison) and with each comparator separately using animal level Mann Whitney tests, with Holm adjustment across visits; reapplication frequency was compared using exact Poisson rate ratios. Results XWRAP demonstrated markedly greater late phase persistence than both comparator products. At Day 14, mean graft integrity score was 3.88 for XWRAP compared with 0.93 for donor matched conventionally processed amnion and 1.69 for the commercial comparator. From Days 10 through 14, XWRAP graft integrity was significantly greater than both comparators (all p[&le;]0.001), with Cliff's {delta} values of 0.95 to1.00. Compared with the pooled comparator groups, XWRAP graft integrity was significantly greater from Day 8 (3.31 vs. 2.93; p=0.022) through Day 14 (3.88 vs. 1.33; p<0.001); differences at Days 10 to14 remained significant after Holm adjustment, and no significant differences were observed during Days 2 to 6. At the terminal Day 14 assessment, none of the XWRAP treated wounds had reached the protocol defined reapplication threshold (0/16; 0%), compared with 11/14 (79%) wounds treated with donor matched conventional amnion and 5/16 (31%) wounds treated with the commercial comparator. Analysis limited to original grafts demonstrated the same persistence pattern, with Day 14 integrity scores of 3.92, 0.90, and 1.83, respectively. The proportion of wounds at the reapplication threshold at Day 14 was significantly lower with XWRAP than with the pooled comparators (0/16 vs. 16/30; p<0.001). Documented reapplications, all of which occurred during Days 2 to 6, did not differ between XWRAP and the pooled comparators (3.24 vs. 3.40 per 100 wound days; rate ratio 0.95, 95% CI 0.33 to2.53; p=1.00). Discussion Proprietary processing produced a substantially different graft persistence profile, with XWRAP remaining largely intact while comparator tissues progressed toward resorption. Importantly, this greater graft persistence complements our previously published findings demonstrating that XWRAP also produced a more favorable wound healing biologic profile across multiple measures of cellular proliferation, inflammation, tissue injury, and wound resolution. Taken together, these findings support two complementary attributes of XWRAP: sustained graft persistence and favorable wound healing biology. The finding that no XWRAP treated wound had reached the reapplication threshold at Day 14 provides a mechanistic rationale for the hypothesis that this combination may extend application intervals and reduce application requirements over a course of wound management.