Body Weight Control by a High-Carbohydrate/Low-Fat Diet Slows the Progression of Diabetic Kidney Damage in an Obese, Hypertensive, Type 2 Diabetic Rat Model

Obesity is one of several factors implicated in the genesis of diabetic nephropathy (DN). Obese, hypertensive, type 2 diabetic rats SHR/NDmcr-cp were given, for 12 weeks, either a normal, middle-carbohydrate/middle-fat diet (MC/MF group) or a high-carbohydrate/low-fat diet (HC/LF group). Daily caloric intake was the same in both groups. Nevertheless, the HC/LF group gained less weight. Despite equivalent degrees of hypertension, hyperglycemia, hyperlipidemia, hyperinsulinemia, and even a poorer glycemic control, the HC/LF group had less severe renal histological abnormalities and a reduced intrarenal advanced glycation and oxidative stress. Mediators of the renoprotection, specifically linked to obesity and body weight control, include a reduced renal inflammation and TGF-beta expression, together with an enhanced level of adiponectin. Altogether, these data identify a specific role of body weight control by a high-carbohydrate/low-fat diet in the progression of DN. Body weight control thus impacts on local intrarenal advanced glycation and oxidative stress through inflammation and adiponectin levels

Advanced glycation in uraemic toxicity.

The Maillard reaction involves the non enzymatic combination of carbohydrates such as glucose with protein aminogroups to yield schiff bases and Amadori protein adducts evolving into irreversible advanced glycation end products (AGEs). This phenomenon, part of normal ageing, is accelerated in diabetes, as a result of hyperglycaemia, and in renal failure, as a consequence of the accumulation of reactive carbonyl compounds (RCOs). AGEs and RCOs are implicated in uraemic toxicity both at the biochemical and the clinical level (dialysis amyloidosis, atherosclerosis, alterations of peritoneal membrane permeability). Reduction of plasma AGEs and RCOs is an interesting avenue to reduce uraemic toxicity. Therapeutic strategies involve dialysis technique (haemodialysis membranes, daily haemodialysis, ultrapure dialysate, RCO free peritoneal dialysate) as well as drugs inhibiting AGE formation (aminoguanidine and the less toxic angiotensin converting enzyme inhibitors or angiotensin receptor blockers)