Hypertensive nephropathy - an increasing clinical problem

Arterial hypertension-related renal damage is an increasingly common problem recently, because approximately 25% of patients currently treated with dialysis were hypertensive before renal replacement therapy was started. Hypertension is also known as a metabolic disease, while carbohydrate, purine and lipid disturbances are the features of this syndrome. On the other hand, the progression of renal disease depends on the extent of tubulointerstitial injury. For this reason, we undertook a study to evaluate the relationship between excretion of the markers of tubular damage (NAG) and some parameters of carbohydrate, purine and lipid metabolism in untreated essential hypertension. Both healthy volunteers (n = 15) aged 32. 6+/-7.8 and essential hypertensives (n = 25) aged 37.24+/-11.39 underwent the same tests. These tests were performed at 2-day intervals: intravenous glucose tolerance test with 0.5 g/kg b.w. as 40% glucose solution and oral fructose load test with 1.0 g/kg b.w. Area under glucose curve (GA) and serum uric acid post-fructose (PUAA) were calculated. Fasting: insulin, total cholesterol and LDL, triglycerides, free fatty acids (FFA) and urine excretion of NAG, albumin were determined. Glomerular filtration rate was estimated as creatinine clearance. Hypertensives showed statistically higher BMI (p<0.007), NAG (p<0.02), total cholesterol (p<0.01), LDL (p<0.007), FFA (p<0.007), insulin (p<0.01), PGA (p<0.01) and PUAA (p<0.03). NAG excretion correlated positively with WHR (r = 0.40), MAP (r = 0.47) and PUAA (r = 0.47) in hypertensives only. We presume that tubular injury at an early stage of renal damage in patients with essential hypertension could be a part of metabolic syndrome X.