We studied viability of adenosine-modified monocytes after cryopreservation and their regenerative potential. The optimal method of cell cryopreservation was the use of serum-free medium followed by storage in liquid nitrogen. Injections of adenosine-modified monocytes after 12-week cryopreservation around grade IIIB burn wound accelerated healing of the skin defect and significantly improved the histological pattern of the damage area at delayed terms.

We studied the effect of mesenchymal stromal cells and conditioned media on healing of full-thickness skin wound in rats. Cell transplantation to the wound bed did not accelerate wound closing and had no effect on the severity of inflammation, but increased vasculariza - tion of the granulation tissue in 14 days after injury. After injection of conditioned medium to the wound, less pronounced inflammation or enhanced epithelialization was observed. The angiogenic effect was observed only after repeated administration of conditioned medium and was associated with slower regeneration, probably due to skin traumatization by repeated injections. At the same time, fetal skin fibroblasts stimulated angiogenesis only after transplantation in high doses and the medium conditioned by these fibroblasts had no effect on wound healing.

Collective cell migration during wound healing has been extensively studied in the epidermis. However, it remains unknown whether the urothelium repairs wounds in a manner similar to the epidermis. By in vivo two-photon excitation microscopy of transgenic mice that express fluorescent biosensors, we studied the collective cell migration of the urothelium in comparison with that of the epidermis. In vivo time-lapse imaging revealed that, even in the absence of a wound, urothelial cells continuously moved and sometimes glided as a sheet over the underlying lamina propria. Upon abrasion of the epithelium, the migration speed of each epidermal cell was inversely correlated with the distance to the wound edge. Repetitive activation waves of extracellular signal-regulated kinase (ERK) were generated at and propagated away from the wound edge. In stark contrast, urothelial cells glided as a large sheet over the lamina propria without any ERK activation waves. Accordingly, the MAPK/ERK kinase inhibitor PD0325901 decreased the migration velocity of the epidermis but not the urothelium. Interestingly, the tyrosine kinase inhibitor dasatinib inhibited migration of the urothelium as well as the epidermis, suggesting that the gliding migration of the urothelium is an active, not a passive, migration. In conclusion, the urothelium glides over the lamina propria to fill wounds in an ERK-independent manner, whereas the epidermis crawls to cover wounds in an ERK-dependent manner.

While mammals cannot regenerate amputated limbs, mice and humans have regenerative ability restricted to amputations transecting the digit tip, including the terminal phalanx (P3). In mice the regeneration process is epimorphic and mediated by the formation of a blastema comprised of undifferentiated proliferating cells that differentiate to regenerate the amputated structures. Blastema formation distinguishes the regenerative response from a scar-forming healing response. The mouse digit tip serves as a pre-clinical model to investigate mammalian blastema formation and endogenous regenerative capabilities. We report that P3 blastema formation initiates prior to epidermal closure and concurrent with the bone histolytic response. In this early healing response, proliferation and cells entering the early stages of osteogenesis are localized to the periosteal and endosteal bone compartments. After the completion of stump bone histolysis, epidermal closure is completed and cells associated with the periosteal and endosteal compartments blend to form the blastema proper. Osteogenesis associated with the periosteum occurs as a polarized progressive wave of new bone formation that extends from the amputated stump and restores skeletal length. Bone patterning is restored along the proximal-distal and medial digit axes, but is imperfect in the dorsal-ventral axis with the regeneration of excessive new bone that accounts for the enhanced regenerated bone volume noted in previous studies. Periosteum depletion studies show that this compartment is required for the regeneration of new bone distal to the original amputation plane. These studies provide evidence that blastema formation initiates early in the healing response and that the periosteum is an essential tissue for successful epimorphic regeneration in mammals. This article is protected by copyright. All rights reserved.

An inflammatory response is the normal response to a burn-induced injury. The burn-associated inflammation can lead to further tissue damage as the tissue tries to repair the damage. Prolonged or excessive inflammation is associated with increased fibrosis of burn wounds and the development of hypertrophic scars. The high incidence of hypertrophic scar formation is one of the many challenges to treating deep partial-thickness burns. Prophylactic treatment to improve burn-induced hypertrophic scarring is lacking. For this reason, we evaluated prophylactic treatment of deep partial-thickness burns with pirfenidone in C57BL/6 mice. Pirfenidone is an FDA-approved anti-fibrotic drug for systemic use in the treatment of idiopathic lung fibrosis and other fibrotic disorders. Additionally, pirfenidone has anti-inflammatory activity. We tested treatment efficacy of pirfenidone using a mouse model of deep partial-thickness burns. Inflammatory cytokines including IL-1β, IL-2, IL-6, IL-13, G-CSF, and MIP-1α, along with neutrophil infiltration, were significantly reduced in wounds when mice were treated during the inflammatory phase of burn wound healing. Additionally, pirfenidone significantly reduced expression of αSMA 12 days after the induction of burns and modestly reduced hydroxyproline in 22-day-old burn wounds. Results show that pirfenidone treatment modulated the inflammatory response of the burn wound. The findings in this study indicate that further examination is required to validate the use of pirfenidone for prophylactic treatment to improve long-term outcomes of scarring and contracture in deep partial-thickness burn wounds.

The early identification and optimized treatment of wound dehiscence are a complex issue, with implications on the patient's clinical and psychological postoperative recovery and on healthcare system costs. The most widely accepted treatment is surgical debridement (also called "wash out"), performed in theater under general anesthesia (GA), followed by either wide-spectrum or targeted antibiotic therapy. Although usually effective, in some cases, such a strategy may be insufficient (generally ill, aged, or immunocompromised patients; poor tissue conditions). Moreover, open revision may still fail, requiring further surgery and, therefore, increasing patients' discomfort. Our objective was to compare the effectiveness, costs, and patients' satisfaction of conventional surgical revision with those of bedside wound dehiscence repair. In 8 years' time, we performed wound debridement in 130 patients. Two groups of patients were identified. Group A (66 subjects) underwent conventional revision under GA in theater; group B (64 cases) was treated under local anesthesia in a protected environment on the ward given their absolute refusal to receive further surgery under GA. Several variables-including length and costs of hospital stay, antibiotic treatment modalities, and success and resurgery rates-were compared. Permanent wound healing was observed within 2 weeks in 59 and 55 patients in groups A and B, respectively. Significantly reduced costs, shorter antibiotic courses, and similar success rates and satisfaction levels were observed in group B compared with group A. In our experience, the bedside treatment of wound dehiscence proved to be safe, effective, and well-tolerated.

Transglutaminase (TG)-2 interacts with matrix proteins and integrins, forming focal adhesions (FA) to initiate cell migration, thus playing a vital role in wound healing. Previously we showed that TG-2 influenced phosphorylation of paxillin and other FA proteins. Here, we aimed to investigate the molecular mechanism of TG-2 regulation of paxillin. Human corneal epithelial cells expressing shRNA against TG-2 (shTG) and scrambled sequence control (shRNA) were cultured. TG-2 was pulled down by anti-paxillin antibody, but not MAP3K12. Cell-free interaction assay with immobilized paxillin shows that TG-2 bind to paxillin directly. JNK was the strongest kinase for paxillin phosphorylation in the in-vitro kinase screen, but TG-2 could not phosphorylate paxillin directly. Increasing TG-2 concentrations did not increase the amount of JNK in the TG-2/paxillin complex. Immunofluoresent staining shows that TG-2 colocalises with vinculin and paxillin in FA of migrating cells. TG-2 binds to paxillin and JNK-containing FA but does not recruit JNK directly. Taken together with previous findings, TG-2 binds paxillin non-covalently, and JNK can phosphorylate paxillin, these processes critically regulate corneal epithelial adhesion and migration.