TNF-α induced extracellular release of keratinocyte high-mobility group box 1 in Stevens-Johnson syndrome/toxic epidermal necrolysis: Biomarker and putative mechanism of pathogenesis.

Decreased epidermal high-mobility group box 1 (HMGB1) expression is an early marker of epidermal injury in Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Etanercept, an anti-tumor necrosis factor therapeutic, is effective in the treatment of SJS/TEN. The objective was to characterize antitumor necrosis factor-alpha (TNF-α)-mediated HMGB1 keratinocyte/epidermal release and etanercept modulation. HMGB1 release from TNF-α treated (± etanercept), or doxycycline-inducible RIPK3 or Bak-expressing human keratinocyte cells (HaCaTs) was determined by western blot/ELISA. Healthy skin explants were treated with TNF-α or serum (1:10 dilution) from immune checkpoint inhibitor-tolerant, lichenoid dermatitis or SJS/TEN patients ± etanercept. Histological and immunohistochemical analysis of HMGB1 was undertaken. TNF-α induced HMGB1 release in vitro via both necroptosis and apoptosis. Exposure of skin explants to TNF-α or SJS/TEN serum resulted in significant epidermal toxicity/detachment with substantial HMGB1 release which was attenuated by etanercept. Whole-slide image analysis of biopsies demonstrated significantly lower epidermal HMGB1 in pre-blistered SJS/TEN versus control (P < 0.05). Keratinocyte HMGB1 release, predominantly caused by necroptosis, can be attenuated by etanercept. Although TNF-α is a key mediator of epidermal HMGB1 release, other cytokines/cytotoxic proteins also contribute. Skin explant models represent a potential model of SJS/TEN that could be utilized for further mechanistic studies and targeted therapy screening.

Terminalia catappa attenuates phenylhydrazine-induced anaemia and hepato-renal toxicity in male Wistar rat by boosting blood cells, modulation of lipoproteins and up-regulation of in vivo antioxidant armouries.

AIM: This study investigated the haematinic, antihyperlipidaemic, hepato-renal protective effects of Terminalia catappa aqueous leaf extract on male Wistar rats exposed to phenylhydrazine toxicity. METHODS: Animals were exposed to phenylhydrazine (PHZ) 50 mg/kg intraperitoneal for two consecutive days thereafter, treated with T. catappa extract (100 mg/kg and 200 mg/kg) orally for 21 days. After the experimentation, animals were sedated with ketamine (70 mg/kg) and euthanized by cervical dislodgement. Blood and organs were collected for haematology and biochemical studies following standard laboratory methods. RESULTS: Our study showed that T. catappa significantly increased erythrocytes, haemoglobin, haematocrit and high density lipoprotein as well as down-regulating leukocytes, thrombocytes, ALP AST, ALT creatinine, urea, total cholesterol as well as low density lipoprotein. The liver, kidney and spleen antioxidant defence were also up-regulated against the adverse effect caused by phenylhydrazine exposure. CONCLUSION: Terminalia catappa attenuated Phenylhydrazine-induced anaemia and hepato-renal toxicity in male Wistar rat by boosting blood cells, modulation of lipoproteins and up-regulation of in vivo antioxidant armouries.