COVID-19 promotes endothelial dysfunction and thrombogenicity: role of proinflammatory cytokines/SGLT2 prooxidant pathway.

BACKGROUND: COVID-19 is associated with an increased risk of cardiovascular complications. Although cytokines have a predominant role in endothelium damage, the precise molecular mechanisms are far from being elucidated. OBJECTIVES: The present study hypothesized that inflammation in patients with COVID-19 contributes to endothelial dysfunction through redox-sensitive SGLT2 overexpression and investigated the protective effect of SGLT2 inhibition by empagliflozin. METHODS: Human plasma samples were collected from patients with acute, subacute, and long COVID-19 (n = 100), patients with non-COVID-19 and cardiovascular risk factors (n = 50), and healthy volunteers (n = 25). Porcine coronary artery endothelial cells (ECs) were incubated with plasma (10%). Protein expression levels were determined using Western blot analyses and immunofluorescence staining, mRNA expression by quantitative reverse transcription-polymerase chain reaction, and the level of oxidative stress by dihydroethidium staining. Platelet adhesion, aggregation, and thrombin generation were determined. RESULTS: Increased plasma levels of interleukin (IL)-1ß, IL-6, tumor necrosis factor-α, monocyte chemoattractant protein-1, and soluble intercellular adhesion molecule-1 were observed in patients with COVID-19. Exposure of ECs to COVID-19 plasma with high cytokines levels induced redox-sensitive upregulation of SGLT2 expression via proinflammatory cytokines IL-1ß, IL-6, and tumor necrosis factor-α which, in turn, fueled endothelial dysfunction, senescence, NF-κB activation, inflammation, platelet adhesion and aggregation, von Willebrand factor secretion, and thrombin generation. The stimulatory effect of COVID-19 plasma was blunted by neutralizing antibodies against proinflammatory cytokines and empagliflozin. CONCLUSION: In patients with COVID-19, proinflammatory cytokines induced a redox-sensitive upregulation of SGLT2 expression in ECs, which in turn promoted endothelial injury, senescence, platelet adhesion, aggregation, and thrombin generation. SGLT2 inhibition with empagliflozin appeared as an attractive strategy to restore vascular homeostasis in COVID-19.

Immunostimulant activities of the aqueous methanolic extract of Leptadenia pyrotechnica, a plant from Cholistan desert.

ETHNOPHARMACOLOGICAL RELEVANCE: Leptadenia pyrotechnica (Forssk.) Decne (Asclepiadaceae) is a well-renowned medicinal shrub, used by herbal practitioners for various ailments including allergic rhinitis, productive cough, abortion, diabetes, stomach disorders, fever, kidney disorders, stones and cancer AIM OF THE STUDY: On the basis of folkloric uses, L. pyrotechnica was selected from the wide medicinal flora of the Cholistan desert of Pakistan, for the exploration of immunomodulatory potential. MATERIALS AND METHODS: Aqueous methanolic (30:70) extract of aerial parts of L. pyrotechnica (Lp. Cr) was prepared by 3 days thrice maceration and subsequent evaporation under reduced pressure. In-vivo experiments were performed in Wistar albino rats including neutrophil adhesion test, haemagglutinating antibody (HA) titre, delayed-type hypersensitivity response, phagocytic activity and cyclophosphamide-induced myelosuppression. RESULTS: Lp. Cr produced a significant increase in phagocytic index in dose-dependent fashion (3.56, 4.18 and 5.42 at 30, 100 and 300mg/kg, respectively) as well as an augmented response in the delayed-type hypersensitivity reaction and HA titre induced by sheep erythrocytes. Lp. Cr also showed improved adhesion of neutrophils with nylon pellets (15.28, 27.85 and 38.42% at the doses of 30, 100 and 300mg/kg) and prevented myelosuppression in cyclophosphamide-treated rats as evidenced from the hematological parameters. The results of treatment were compared with normal and standard control groups throughout the study and the effects by Lp. Cr (300mg/kg) were found to be comparable with Levamisole. CONCLUSIONS: The results indicated that L. pyrotechnica possesses immunostimulatory activity and justify its traditional use for the control and management of diseases in which the immune system needs to be stimulated like infectious diseases.