Mechanisms of Obesity-Related Kidney Disease: From Adipose Depot Biology to the Chymase-Aldosterone and Ghrelin-Leptin Axes.

Obesity is an increasingly important and modifiable driver of chronic kidney disease (CKD), with effects that extend well beyond its associations with type 2 diabetes, hypertension, and dyslipidemia. To synthesize the evidence that excess adiposity is a causal and modifiable determinant of kidney disease, and to examine how specific adipose depots injure the glomerulus and the tubulointerstitium, and then map these mechanisms onto established and emerging therapies. Throughout, obesity-related kidney disease (ORKD) denotes the full spectrum of diposity-driven renal injury, whereas obesity-related glomerulopathy (ORG) is reserved for the biopsy-defined glomerular lesion. Central, visceral, perirenal and renal-sinus adiposity act first through structural and haemodynamic mechanisms, promoting glomerular hyperfiltration, mechanical renal compression and activation of the adipose-derived renin-angiotensin-aldosterone system (RAAS). In parallel, these depots drive cellular and metabolic injury through lipotoxicity, adipokine imbalance, sterile inflammation, oxidative stress, gut dysbiosis, mitochondrial dysfunction, epigenetic remodelling and cellular senescence. Ectopic lipid accumulation within the renal parenchyma-fatty kidney-offers a unifying description of these changes and is most marked in type 2 diabetes mellitus. These interacting processes converge on podocyte stress, tubular metabolic failure, endothelial dysfunction and interstitial fibrosis, producing a phenotypic continuum that ranges from early albuminuria to obesity-related glomerulopathy and progressive CKD. Within the RAAS limb we highlight two comparatively underappreciated, adiposity-linked routes to injury: adipocyte-derived leptin directly upregulates adrenal aldosterone synthase (CYP11B2), and mast-cell chymase generates angiotensin II independently of angiotensin-converting enzyme, together reinforcing aldosterone- and angiotensin II-mediated damage that conventional RAAS blockade only partially interrupts. We further consider the counter-regulatory ghrelin-leptin axis, in which the suppression of ghrelin that accompanies obesity may withdraw an antioxidant, anti-inflammatory and podocyte-protective signal precisely as leptin-driven glomerular injury intensifies, positioning ghrelin as a plausible modulator and candidate biomarker of obesity-related kidney injury. We also examine how obesity complicates renal risk assessment, drug dosing, dialysis delivery and transplant access. Emerging, mechanism-matched therapies-SGLT2 inhibitors, GLP-1 receptor agonists, finerenone, structured lifestyle intervention, metabolic-bariatric surgery and, most recently, aldosterone synthase inhibitors that suppress the chymase- and leptin-driven aldosterone escaping receptor blockade-now enable a precision cardiovascular-kidney-metabolic framework that aligns adipose-depot biology, biomarkers, histology and treatment response to guide mechanism-based care in ORKD.