title: Renal function in diabetic disease models: the tubular system in the pathophysiology of the diabetic kidney.
abstract: Diabetes mellitus affects the kidney in stages. At the onset of diabetes mellitus, in a subset of diabetic patients the kidneys grow large, and glomerular filtration rate (GFR) becomes supranormal, which are risk factors for developing diabetic nephropathy later in life. This review outlines a pathophysiological concept that focuses on the tubular system to explain these changes. The concept includes the tubular hypothesis of glomerular filtration, which states that early tubular growth and sodium-glucose cotransport enhance proximal tubule reabsorption and make the GFR supranormal through the physiology of tubuloglomerular feedback. The diabetic milieu triggers early tubular cell proliferation, but the induction of TGF-β and cyclin-dependent kinase inhibitors causes a cell cycle arrest and a switch to tubular hypertrophy and a senescence-like phenotype. Although this growth phenotype explains unusual responses like the salt paradox of the early diabetic kidney, the activated molecular pathways may set the stage for tubulointerstitial injury and diabetic nephropathy.
authors.affiliation: Department of Medicine, University of California San Diego, La Jolla, California 92093, USA. vvallon@ucsd.edu
authors.forename: Volker
authors.initials: V
authors.lastname: Vallon
authors.forename: Scott C
authors.initials: SC
authors.lastname: Thomson
mesh_terms: D000818:Animals; D003928:Diabetic Nephropathies / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D018450:Disease Progression; D004573:Electrolytes / Q000378:metabolism; D025461:Feedback, Physiological; D005919:Glomerular Filtration Rate / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative / Q000378:metabolism; D051273:Glucose Transporter Type 2 / Q000378:metabolism; D006801:Humans; D006984:Hypertrophy; D007678:Kidney Glomerulus / Q000378:metabolism / Q000503:physiopathology; D007684:Kidney Tubules / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D007687:Kidney Tubules, Proximal / Q000473:pathology; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism
chemical_list: D004573:Electrolytes; D051246:Glucose Transport Proteins, Facilitative; D051273:Glucose Transporter Type 2; D012965:Sodium Chloride; D012964:Sodium; D005947:Glucose