Acute kidney injury (AKI) is a leading cause of distant organ dysfunction among critically ill patients. Mitochondrial dysfunction is considered a key factor driving the damage after renal ischemia–reperfusion (IR) injury. Damaged mitochondria release mitochondrial damage-associated molecular patterns (mtDAMPs) into the cytosol, which initiate a systemic inflammatory response. To better understand the underlying mechanism, mice were challenged with 30 min of bilateral renal ischemia followed by 24 h of reperfusion. The cytokine profiling in mouse lung tissues revealed that TREM-1 was significantly increased. Western Blot (WB) analysis demonstrated that the cGAS and STING pathway was increased in AKI mice. Transmission electron microscopy (TEM) images indicated that the mtDAMPs were released from damaged kidney mitochondria. Injection of mtDAMPs into mice induced an inflammatory response in the lungs similar to that induced by AKI. Mouse macrophages and lung epithelial cells were utilized to verify if inhibition of the TREM-1 and cGAS-STING pathways reduces mtDAMP-induced lung injury. Electric Cell-substrate Impedance Sensing (ECIS) results demonstrated that inhibiting the TREM-1 and cGAS-STING pathways significantly increased cell proliferation and migration while reducing mtDAMP-induced cytotoxicity. In conclusion, our findings suggest that targeting TREM-1 and cGAS-STING has the potential to attenuate acute lung injury in IR-AKI.

Acute limb ischemia (ALI) is a sudden lack of blood flow to a limb, primarily caused by arterial embolism and thrombosis. Various experimental animal models, including non-invasive and invasive methods, have been developed and successfully used to induce limb ischemia-reperfusion injuries (L-IRI). However, there is no consensus on the methodologies used in animal models for L-IRI, particularly regarding the assessment of functional recovery. The present study aims to compare different approaches that induce L-IRI and determine the optimal animal model to study functional limb recovery. In this study, we applied a pneumatic cuff as a non-invasive method and ligated the aorta, iliac, or femoral artery as invasive methods to induce L-IRI. We have measured grip strength, motor function, creatine kinase level, inflammatory markers such as nuclear factor NF-κB, interleukin-6 (IL-6), hypoxia markers such as hypoxia-induced factor-1$\mathsf{\alpha }$ (HIF-1$\mathsf{\alpha }$), and evaluated the muscle injury with hematoxylin and eosin (H&E) staining in Sprague Dawley rats after inducing L-IRI. The pneumatic pressure cuff method significantly decreased the muscle strength of the rats, causing the loss of ability to hold the grid and inducing significant limb function impairment, while artery ligations did not. We conclude from this study that the tourniquet cuff method could be ideal for studying functional recovery after L-IRI in the rat model.

This study explored mechanisms underlying the natriuretic effects of mammalian target of rapamycin protein complex 2 inhibition using PP242 and revealed both epithelial Na⁺ channel and Na-Cl cotransporter in the distal tubular segments were potentially inhibited. These observations, with prior lab evidence, indicate that PP242 prevents hypertension via its potent inhibitory effects on these specific sodium transporters and by reducing renal immune responses. This dual action, coupled with potassium sparing effects, suggests an improved approach for managing hypertension and associated kidney damage.

Limb ischemia-reperfusion injury (L-IRI) causes severe skeletal muscle damage and functional impairment through activation of regulated cell-death and inflammatory pathways. Necroptosis is a regulated form of necrotic cell death mediated through the receptor-interacting protein kinase 1 (RIPK1)-RIPK3-mixed lineage kinase domain-like protein (MLKL) signaling axis. Prior experimental studies have shown that Necrostatin-1 (Nec-1) attenuates acute skeletal muscle ischemia-reperfusion injury in rats. However, how Nec-1-sensitive protection relates to RIPK1/MLKL-associated signaling, circulating muscle injury markers, inflammatory responses, histological damage, and functional recovery during the early postischemic period remains incompletely defined. In this study, we used a rat model of unilateral hindlimb ischemia involving 3 hours of ischemia followed by reperfusion for up to 7 days to evaluate these interrelated responses. Nec-1 was administered before ischemia and after reperfusion. L-IRI resulted in elevated plasma creatine kinase and lactate dehydrogenase levels, severe histopathological injury, increased TUNEL staining, impaired grip strength, and reduced Modified Tarlov scores. These changes were accompanied by increased phosphorylation of RIPK1 and MLKL, activation of inflammatory signaling pathways, and altered expression of injury-associated inflammatory mediators. Nec-1 treatment reduced RIPK1/MLKL-associated signaling, inflammatory mediator expression, circulating muscle injury markers, and histological injury while preserving muscle architecture and improving functional recovery. These findings support and extend previous evidence that Nec-1-sensitive necroptosis-associated signaling contributes to early skeletal muscle injury following L-IRI. Pharmacologic targeting of regulated necrotic and inflammatory pathways warrants further investigation as a potential adjunct strategy for limiting acute skeletal muscle injury after limb reperfusion.