Background Impaired hepatic fatty acid metabolism and persistent mitochondrial dysfunction are phenomena commonly associated with liver failure. Decreased serum levels of L-carnitine, a amino acid derivative involved in fatty-acid and energy metabolism, have been reported in severe burn patients. The current study aimed to evaluate the effects of L-carnitine supplementation on mitochondrial damage and other hepatocyte injuries following severe burns and the related mechanisms. Methods Serum carnitine and other indicators of hepatocytic injury, including AST, ALT, LDH, TG, and OCT, were analyzed in severe burn patients and healthy controls. A burn model was established on the back skin of rats; thereafter, carnitine was administered, and serum levels of the above indicators were evaluated along with Oil Red O and TUNEL staining, transmission electron microscopy, and assessment of mitochondrial membrane potential and carnitine palmitoyltransferase 1 (CPT1) activity and expression levels in the liver. HepG2 cells pretreated with the CPT1 inhibitor etomoxir were treated with or without carnitine for 24 h. Next, the above indicators were examined, and apoptotic cells were analyzed via flow cytometry. High-throughput sequencing of rat liver tissues identified several differentially expressed genes (Fabp4, Acacb, Acsm5, and Pnpla3) were confirmed using RT-qPCR. Results Substantially decreased serum levels of carnitine and increased levels of AST, ALT, LDH, and OCT were detected in severe burn patients and the burn model rats. Accumulation of TG, evident mitochondrial shrinkage, altered mitochondrial membrane potential, decreased ketogenesis, and reduced CPT1 activity were detected in the liver tissue of the burned rats. Carnitine administration recovered CPT1 activity and improved all indicators related to cellular and fatty acid metabolism and mitochondrial injury. Inhibition of CPT1 activity with etomoxir induced hepatocyte injuries similar to those in burn patients and burned rats; carnitine supplementation restored CPT1 activity and ameliorated these injuries. The expression levels of the differentially expressed genes Fabp4, Acacb, Acsm5, and Pnpla3 in the liver tissue from burned rats and etomoxir-treated hepatocytes were also restored by treatment with exogenous carnitine. Conclusion Exogenous carnitine exerts protective effects against severe burn-induced cellular, fatty-acid metabolism, and mitochondrial dysfunction of hepatocytes by restoring CPT1 activity.

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Introduction. Dead space is an important risk factor for poor wound healing; therefore, it is important to effectively fill deep dead space through individualized tissue flap design during the repair of complex wounds. Adipofascial flaps have yielded good results in the repair of deep dead space wounds. Objective. The authors evaluated the efficacy of 3 kinds of adipofascial flaps to repair deep dead space wounds. Methods. From January 2019 to January 2022, 15 patients with complicated wounds accompanied by deep dead space underwent repair via 1 of 3 kinds of adipofascial flaps, and the clinical efficacy was observed. Results. All 15 transplanted adipofascial flaps exhibited complete survival, and within a mean follow-up of 14.7 months, both the donor and recipient sites had successfully healed. Conclusion. The traditional pedicled adipofascial flap was used to repair single deep dead space wounds, and pedicled perforator adipofascial extension flaps or layered fasciocutaneous flaps were used on compound tissue defect wounds, thus providing a relatively simple, safe, and effective method to repair a small area of tissue defect with deep dead space wounds.

Introduction. Repair of complex wounds of the lower extremity remains challenging for clinicians. When repairing complex wounds, it is necessary to customize the skin flap to simultaneously repair both the superficial soft tissue defect and the deep dead space wound. Objective. This case series describes the use of a layered fasciocutaneous flap with pedicled perforator to repair complex wounds of the lower extremity. Materials and Methods. Three cases with complex wounds of the lower extremity underwent repair using layered fasciocutaneous flap, and clinical efficacy was observed. Results. In cases 1 and 3, complete survival of the layered flaps was achieved. In case 2, congestion measuring 1 cm × 1 cm occurred at the distal end of the skin paddle, followed by superficial skin ulceration, which healed 2 weeks after a dressing change. Conclusion. These findings indicate that a layered fasciocutaneous flap with pedicled perforator can be used to repair complex wounds of the lower extremity.