Downregulation of Lectin-like Oxidized Low-Density Lipoprotein Receptor-1 After Ischemic Preconditioning in Ischemia-Reperfused Rat Kidneys

Targeting HIF-1α to Prevent Renal Ischemia-Reperfusion Injury: Does It Work?

Partial nephrectomy (open or minimally invasive) usually requires temporary renal arterial occlusion to limit intraoperative bleeding and improve access to intrarenal structures. This is a time-critical step due to the critical ischemia period of renal tissue. Prolonged renal ischemia may lead to irreversible nephron damage in the remaining tissue and, ultimately, chronic kidney disease. This is potentiated by the incompletely understood ischemia-reperfusion injury (IRI). A key mechanism in IRI prevention appears to be the upregulation of an intracellular transcription protein, Hypoxia-Inducible Factor (HIF). HIF mediates metabolic adaptation, angiogenesis, erythropoiesis, cell growth, survival, and apoptosis. Upregulating HIF-1α via ischemic preconditioning (IPC) or drugs that simulate hypoxia (hypoxia-mimetics) has been investigated as a method to reduce IRI. While many promising chemical agents have been trialed for the prevention of IRI in small animal studies, all have failed in human trials. The aim of this review is to highlight the techniques and drugs that target HIF-1α and ameliorate IRI associated with renal ischemia. Developing a technique or drug that could reduce the risk of acute kidney injury associated with renal IRI would have an immediate worldwide impact on multisystem surgeries that would otherwise risk ischemic tissue injury.

Molecular Mechanisms of Renal Ischemic Conditioning Strategies

Ischemia-reperfusion injury is the leading cause of acute kidney injury in a variety of clinical settings such as renal transplantation and hypovolemic and/or septic shock. Strategies to reduce ischemia-reperfusion injury are obviously clinically relevant. Ischemic conditioning is an inherent part of the renal defense mechanism against ischemia and can be triggered by short periods of intermittent ischemia and reperfusion. Understanding the signaling transduction pathways of renal ischemic conditioning can promote further clinical translation and pharmacological advancements in this era. This review summarizes research on the molecular mechanisms underlying both local and remote ischemic pre-, per- and postconditioning of the kidney. The different types of conditioning strategies in the kidney recruit similar powerful pro-survival mechanisms. Likewise, renal ischemic conditioning mobilizes many of the same protective signaling pathways as in other organs, but differences are recognized.

LOX-1, oxidative stress and inflammation: a novel mechanism for diabetic cardiovascular complications

Diabetes mellitus is a common metabolic disease characterized by a state of oxidative stress, inflammation and endothelial dysfunction. This malady can lead to a number of complications such as ischemic heart disease, nephropathy, neuropathy, retinopathy and impaired wound healing. The etiology of diabetic complications is multifactorial, and is closely associated with oxidative stress and inflammation. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a receptor for oxidized low density lipoprotein (ox-LDL), plays critical roles in multiple signal transduction pathways and is involved in the process of oxidative stress and inflammation. Recent studies provide important insights into the roles of LOX-1 in the development and progression of diabetic vasculopathy which is the underlying mechanism of diabetic complications. In this review, we summarize mechanistic studies, mainly related to LOX-1, on the development and progression of diabetes mellitus and its cardiovascular complications.