Capsaicin mitigates ventilator-induced lung injury by suppressing ferroptosis and maintaining mitochondrial redox homeostasis through SIRT3-dependent mechanisms.

BACKGROUND: Ventilator-induced lung injury (VILI) is one of the severe complications in the clinic concerning mechanical ventilation (MV). Capsaicin (CAP) has anti-inflammatory and inhibitory effects on oxidative stress, which is a significant element causing cellular ferroptosis. Nevertheless, the specific role and potential mechanistic pathways through which CAP modulates ferroptosis in VILI remain elusive. METHODS: VILI was established in vivo, and the pulmonary epithelial cell injury model induced by circulation stretching (CS) was established in vitro. Both mice and cells were pretreated with CAP. Transmission electron microscopy, ELISA, Western blot, immunofluorescence, RT-PCR, fluorescent probes, and other experimental methods were used to clarify the relationship between iron death and VILI in alveolar epithelial cells, and whether capsaicin alleviates VILI by inhibiting iron death and its specific mechanism. RESULTS: Ferroptosis was involved in VILI by utilizing in vivo models. CAP inhibited ferroptosis and alleviated VILI's lung damage and inflammation, and this protective effect of CAP was dependent on maintaining mitochondrial redox system through SITR3 signaling. In the CS-caused lung epithelial cell injury models, CAP reduced pathological CS-caused ferroptosis and cell injury. Knockdown SIRT3 reversed the role of CAP on the maintaining mitochondria dysfunction under pathological CS and eliminated its subsequent advantageous impacts for ferroptosis against overstretching cells. CONCLUSION: The outcomes showed that CAP alleviated ferroptosis in VILI via improving the activity of SITR3 to suppressing mitochondrial oxidative damage and maintaining mitochondrial redox homeostasis, illustrating its possibility as a novel therapeutic goal for VILI.

GSDMD promotes neutrophil extracellular traps via mtDNA-cGAS-STING pathway during lung ischemia/reperfusion.

Lung ischemia/reperfusion injury (LIRI) is a complex pathophysiological process, with the histopathological hallmark of neutrophils migrating into the lungs. Neutrophil extracellular traps (NETs) have been suggested to exert a critical role in the pathogenesis of inflammation and infection in humans and animals, while the exact functions and underlying mechanisms of NETs in LIRI remain insufficiently elucidated. In this study, we investigated the role of pore-forming protein gasdermin D (GSDMD) on NETs release in LIRI induced by lung ischemia/reperfusion (I/R). We found that disulfiram, a GSDMD inhibitor, dramatically reduced NETs release and pathological injury in lung I/R in vivo and in vitro. Additionally, GSDMD caused mitochondrial DNA (mtDNA) leaking into the neutrophil cytosol, and then the cytoplasmic mtDNA activated the cGAS-STING signaling pathway and stimulated NETs formation in lung I/R. Furthermore, inhibition of cGAS/STING pathway could inhibit cytosol mtDNA mediated NETs formation.

Cancer-Related Anemia Is a Risk Factor for Medium-Term Postoperative Cognitive Dysfunction in Laparoscopic Surgery Patients: An Observational Prospective Study.

Anemia in the elderly may impair cognitive function. Our primary objective was to determine whether cancer-related anemia was associated with postoperative cognitive dysfunction (POCD) in nonelderly patients. We conducted an observational prospective study of 177 patients scheduled for laparoscopic surgery. Patients aged 18-64 were divided into two groups according to whether they were anemic due to cancer or not. The cognitive function was assessed by the Mini-Mental State Examination (MMSE) 1 day before and 1 week after operation. The cognitive function of the patients was evaluated by using the Telephone Interview for Cognitive Status-Modified (TICS-M) 3 months after operation. The quality of life of patients was evaluated after operation. The hemoglobin level and other clinical data were recorded before operation. Of the 170 patients, 100 without anemia and 70 anemia patients had been evaluated 1 week after operation. POCD was detected in 43 cases (25.3% of 170 cases) at 1 week and 30 cases (19% of 158 cases) at 3 months postoperatively. Anemia was an independent risk factor for 3-month POCD occurrence (P = 0.034). The education level of the patients who had POCD at 1 week and 3 months after operation was lower (P < 0.001, P = 0.011, respectively). Age was independently associated with the incidence of POCD at 3 months (P = 0.011). In general, these findings suggested that anemia may increase the incidence of medium-term POCD in cancer patients undergoing laparoscopic surgery.