Disorders of Carbohydrate and Lipid Metabolism in Renal Disease: A Short Review

Gut-kidney axis in IgA nephropathy: Role on mesangial cell metabolism and inflammation

IgA Nephropathy (IgAN) is the commonest primary glomerular disease around the world and represents a significant cause of end-stage renal disease. IgAN is characterized by mesangial deposition of IgA-immune complexes and mesangial expansion. The pathophysiological process includes an abnormally glycosylated IgA1, which is an antigenic target. Autoantibodies specifically recognize galactose-deficient IgA1 forming immune complexes that are amplified in size by the soluble IgA Fc receptor CD89 leading to deposition in the mesangium through interaction with non-classical IgA receptors. The local production of cytokines promotes local inflammation and complement system activation, besides the stimulation of mesangial proliferation. The spectrum of clinical manifestations is quite variable from asymptomatic microscopic hematuria to rapidly progressive glomerulonephritis. Despite all the advances, the pathophysiology of the disease is still not fully elucidated. The mucosal immune system is quoted to be a factor in triggering IgAN and a "gut-kidney axis" is proposed in its development. Furthermore, many recent studies have demonstrated that food intake interferes directly with disease prognosis. In this review, we will discuss how mucosal immunity, microbiota, and nutritional status could be interfering directly with the activation of intrinsic pathways of the mesangial cells, directly resulting in changes in their function, inflammation and development of IgAN.

Hyperlipoproteinaemia and dietary fat modification in haemodialysis and renal transplant patients

A group of patients in a haemodialysis and renal transplant programme have been assessed for the frequency of lipid abnormalities. Hypercholesterolaemia was not a significant problem amongst haemodialysis patients, but mild hypercholesterolaemia was common amonst transplant patients. Mild hypertriglyceridaemia was a feature of both haemodialysis and transplant patients. Irrespective of initial lipid values, each patient was advised to undertake dietary fat modification for a period of eight months. There was a small significant lowering of plasma triglyceride values in the haemodialysis group. It is concluded that major lipid abnormalities are not a feature of this group and that the return for dietary fat modification is small, although occasional individual patients may warran hypolipidaemic therapy.

Plasma triglyceride secretion and metabolism in chronic renal failure

Endogenous very low density lipoprotein triglyceride (VLDL-TG) production rate has been studied in 13 patients with chronic renal failure who were not on dialysis treatment. In these patients the VLDL-TG plasma concentration was significanlty raised when compared with the control group; the fractional turnover rate was reduced but the absolute turnover rate was increased. The results suggest that increased hepatic production of VLDL-TG is a contributory factor to the hypertriglyceridaemia of chronic renal failure.