Leptin and fractalkine: novel subcutaneous cytokines in burn injury

LEP and LEPR are possibly a double-edged sword for wound healing

Wound healing is a complex and error-prone process. Wound healing in adults often leads to the formation of scars, a type of fibrotic tissue that lacks skin appendages. Hypertrophic scars and keloids can also form when the wound-healing process goes wrong. Leptin (Lep) and leptin receptors (LepRs) have recently been shown to affect multiple stages of wound healing. This effect, however, is paradoxical for scarless wound healing. On the one hand, Lep exerts pro-inflammatory and profibrotic effects; on the other hand, Lep can regulate hair follicle growth. This paper summarises the role of Lep and LepRs on cells in different stages of wound healing, briefly introduces the process of wound healing and Lep and LepRs, and examines the possibility of promoting scarless wound healing through spatiotemporal, systemic, and local regulation of Lep levels and the binding of Lep and LepRs.

Elevated 18:0 lysophosphatidylcholine contributes to the development of pain in tissue injury

ABSTRACT

Tissue injuries, including burns, are major causes of death and morbidity worldwide. These injuries result in the release of intracellular molecules and subsequent inflammatory reactions, changing the tissues' chemical milieu and leading to the development of persistent pain through activating pain-sensing primary sensory neurons. However, the majority of pain-inducing agents in injured tissues are unknown. Here, we report that, amongst other important metabolite changes, lysophosphatidylcholines (LPCs) including 18:0 LPC exhibit significant and consistent local burn injury-induced changes in concentration. 18:0 LPC induces immediate pain and the development of hypersensitivities to mechanical and heat stimuli through molecules including the transient receptor potential ion channel, vanilloid subfamily, member 1, and member 2 at least partly via increasing lateral pressure in the membrane. As levels of LPCs including 18:0 LPC increase in other tissue injuries, our data reveal a novel role for these lipids in injury-associated pain. These findings have high potential to improve patient care.

Luteolin is an Effective Component of Platycodon grandiflorus in Promoting Wound Healing in Rats with Cutaneous Scald Injury

Background

Platycodon grandiflorus could significantly improve the pathological results of cutaneous scald injury, reduce the release of inflammatory factors and promote angiogenesis. This study investigated the wound healing effect of luteolin, an active component of P. grandiflorus, on induced cutaneous scald injury in Sprague-Dawley (SD) rats.

Methods

The protein expression levels of TNF-α and IL-6 were detected by ELISA. QRT-PCR was adopted to detect the expression of TGF-β1 and VEGF. Histopathological changes of scald wounds were analyzed by hematoxylin-eosin staining. Cell viability and migration ability were detected by CCK-8 assay and scratch assay.

Results

Both in vivo and in vitro experiments showed that luteolin promoted wound healing of cutaneous scald injury. Gene Oncology (GO) functional analysis and rescue experiments showed that endothelial nitric oxide synthase 3 (NOS3) was the critical target of luteolin in treating cutaneous scald.

Conclusion

This study demonstrated that luteolin is an effective component of P. grandiflorus and is effective in the treatment of cutaneous scald injury.

A novel human ex vivo skin model to study early local responses to burn injuries

Burn injuries initiate numerous processes such as heat shock response, inflammation and tissue regeneration. Reliable burn models are needed to elucidate the exact sequence of local events to be able to better predict when local inflammation triggers systemic inflammatory processes. In contrast to other ex vivo skin culture approaches, we used fresh abdominal skin explants to introduce contact burn injuries. Histological and ultrastructural analyses confirmed a partial-thickness burn pathology. Gene expression patterns and cytokine production profiles of key mediators of the local inflammation, heat shock response, and tissue regeneration were analyzed for 24 h after burn injury. We found significantly increased expression of factors involved in tissue regeneration and inflammation soon after burn injury. To investigate purely inflammation-mediated reactions we injected lipopolysaccharide into the dermis. In comparison to burn injury, lipopolysaccharide injection initiated an inflammatory response while expression patterns of heat shock and tissue regeneration genes were unaffected for the duration of the experiment. This novel ex vivo human skin model is suitable to study the local, early responses to skin injuries such as burns while maintaining an intact overall tissue structure and it gives valuable insights into local mechanisms at the very beginning of the wound healing process after burn injuries.