PROTECTIVE EFFECTS OF HUMANIN-G IN HEMORRHAGIC SHOCK IN FEMALE MICE VIA AMPKα1-INDEPENDENT MECHANISMS

METFORMIN MITIGATES SEPSIS-ASSOCIATED PULMONARY FIBROSIS BY PROMOTING AMPK ACTIVATION AND INHIBITING HIF-1α-INDUCED AEROBIC GLYCOLYSIS

ABSTRACT

Recent research has revealed that aerobic glycolysis has a strong correlation with sepsis-associated pulmonary fibrosis (PF). However, at present, the mechanism and pathogenesis remain unclear. We aimed to test the hypothesis that the adenosine monophosphate-activated protein kinase (AMPK) activation and suppression of hypoxia-inducible factor 1α (HIF-1α)-induced aerobic glycolysis play a central role in septic pulmonary fibrogenesis. Cellular experiments demonstrated that lipopolysaccharide increased fibroblast activation through AMPK inactivation, HIF-1α induction, alongside an augmentation of aerobic glycolysis. By contrast, the effects were reversed by AMPK activation or HIF-1α inhibition. In addition, pretreatment with metformin, which is an AMPK activator, suppresses HIF-1α expression and alleviates PF associated with sepsis, which is caused by aerobic glycolysis, in mice. Hypoxia-inducible factor 1α knockdown demonstrated similar protective effects in vivo . Our research implies that targeting AMPK activation and HIF-1α-induced aerobic glycolysis with metformin might be a practical and useful therapeutic alternative for sepsis-associated PF.

SERUM HUMANIN IN PEDIATRIC SEPTIC SHOCK-ASSOCIATED MULTIPLE-ORGAN DYSFUNCTION SYNDROME

ABSTRACT

Background: Multiple-organ dysfunction syndrome disproportionately contributes to pediatric sepsis morbidity. Humanin (HN) is a small peptide encoded by mitochondrial DNA and thought to exert cytoprotective effects in endothelial cells and platelets. We sought to test the association between serum HN (sHN) concentrations and multiple-organ dysfunction syndrome in a prospectively enrolled cohort of pediatric septic shock. Methods: Human MT-RNR2 ELISA was used to determine sHN concentrations on days 1 and 3. The primary outcome was thrombocytopenia-associated multiorgan failure (TAMOF). Secondary outcomes included individual organ dysfunctions on day 7. Associations across pediatric sepsis biomarker (PERSEVERE)-based mortality risk strata and correlation with platelet and markers of endothelial activation were tested. Results: One hundred forty subjects were included in this cohort, of whom 39 had TAMOF. The concentration of sHN was higher on day 1 relative to day 3 and among those with TAMOF phenotype in comparison to those without. However, the association between sHN and TAMOF phenotype was not significant after adjusting for age and illness severity in multivariate models. In secondary analyses, sHN was associated with presence of day 7 sepsis-associated acute kidney injury ( P = 0.049). Furthermore, sHN was higher among those with high PERSEVERE-mortality risk strata and correlated with platelet counts and several markers of endothelial activation. Conclusion: Future investigation is necessary to validate the association between sHN and sepsis-associated acute kidney injury among children with septic shock. Furthermore, mechanistic studies that elucidate the role of HN may lead to therapies that promote organ recovery through restoration of mitochondrial homeostasis among those critically ill.