The Benefit of Microskin in Combination With Autologous Keratinocyte Suspension to Treat Full Skin Loss In Vivo

Within-patient randomised clinical trial exploring the development of microskin implantation in the treatment of pressure ulcers

Pressure injury often seriously affects the life quality of aged patients, especially the long-term bedridden casualties. Widely adopted by different disciplines, negative pressure suction has its role in pressure injury. Microskin implantation has been demonstrated powerful in increasing the expansion ratio of donor area-derived skin and accelerating wound healing by forming "skin islands". The study was designed to evaluate the efficacy and safety of additional use of bedside microskin implantation in the palliative care of pressure injury of aged patients who cannot tolerate surgical treatment as a supplement for standard negative pressure suction. An open-label within-patient RCT was conducted in aged patients with pressure injury. Sixteen patients were enrolled. After granulation tissues formed, half of a pressure injury was randomised to receive the negative pressure suction as the control group, and the other half exposed to additional bedside microskin implantation as the experimental group. Efficacy was evaluated within 1 month after treatment, and the primary endpoints included the wound healing rate and pressure ulcer scale for healing (PUSH) scores. The secondary outcomes included survival rate of implanted microskin, pain intensity assessment, satisfaction surveys from patients or their family, and pressure ulcer healing complications. Sixteen patients completed the study. After 14 days of operation, 5.63 ± 1.78 out of 10 pieces of implanted microskin survived and formed neonatal epithelium. The wound healing rates of the control group and the experimental group at 1 month were (26.17 ± 9.03%) and (35.95 ± 16.02%), respectively (P < .01). The mean PUSH score before the surgery was 12.38 ± 2.23. At 1 month after surgery, the mean difference of PUSH score from baseline was 2.13 ± 0.96 in the control group and 2.81 ± 0.83 in the experimental group (P < .01). The treatment of microskin implantation did not cause additional pain or complications to the patients. Accompanied by a better ulcer status, the majority of patients or their guardians have a high degree of acceptance towards the microskin implantation. Bedside microskin implantation could accelerate wound healing with lower PUSH scores. As a complementary palliative treatment, supplementary microskin implantation is effective and well tolerated.

Microskin-Inspired Injectable MSC-Laden Hydrogels for Scarless Wound Healing with Hair Follicles

Scarless skin regeneration with functional tissue remains a challenge for full-thickness wounds. Here, mesenchymal stem cell (MSC)-laden hydrogels are developed for scarless wound healing with hair follicles. Microgels composed of aligned silk nanofibers are used to load MSCs to modulate the paracrine. MSC-laden microgels are dispersed into injectable silk nanofiber hydrogels, forming composites biomaterials containing the cells. The injectable hydrogels protect and stabilize the MSCs in the wounds. The synergistic action of silk-based composite hydrogels and MSCs stimulated angiogenesis and M1-M2 phenotype switching of macrophages, provides a suitable niche for functional recovery of wounds. Compared to skin defects treated with MSC-free hydrogels, the defects treated with the MSC-laden composite hydrogels heal faster and form scarless tissues with hair follicles. Wound healing can be further improved by adjusting the ratio of silk nanofibers and particles and the loaded MSCs, suggesting tunability of the system. To the best of current knowledge, this is the first time scarless skin regeneration with hair follicles based on silk material systems is reported. The improved wound healing capacity of the systems suggests future in vivo studies to compare to other biomaterial systems related to clinical goals in skin regeneration in the absence of scarring.