Renal protective effects of enalapril in hypertensive NIDDM: role of baseline albuminuria.

The primary results of a three-year prospective, double-blind, placebo-controlled trial in non-insulin-dependent diabetic (NIDDM) patients show that an anti-hypertensive regimen, which includes the ACE inhibitor enalapril, preserves renal function to a greater extent than therapy with antihypertensive agents excluding ACE inhibitors (J Am Soc Nephrol 3:335, 1992). The influence of baseline urinary albumin excretion on the renal protective effects of enalapril treatment in these subjects was the objective of this further analysis. Adequate data were available in 121 patients of the 165 hypertensive NIDDM individuals studied [baseline glomerular filtration rate (GFR) 30 to 100 ml/min/1.73 m2]. Twenty-four hour urinary excretion of albumin (UAE), protein, urea nitrogen, creatinine and isotopically determined GFR were measured at baseline and six month intervals. Glycemic control and blood pressure regulation were assessed every three months. The rate of loss of GFR was significantly greater in patients with overt proteinuria at baseline (UAE > 300 mg/24 hr) as compared to patients with baseline sub-clinical proteinuria (UAE < or = 300 mg/24 hr). Antihypertensive treatment with enalapril preserved GFR significantly better (P < 0.01) in the patients with sub-clinical proteinuria at baseline (UAE < or = 300 mg/24 hr) than other antihypertensive treatments which excluded the ACE inhibitor. Furthermore, only 7% of the enalapril-treated group progressed to clinical albuminuria compared to 21% of control treated patients. Although the enalapril-treated group had a lower mean blood pressure during the maintenance period, no correlation between blood pressure (systolic, diastolic or mean arterial) and rate of change of GFR was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

A genetic determinant of the phenotypic variance of the molecular weight of low density lipoprotein.

The molecular weight of monodisperse human plasma low densitylipoprotein has been measured in 69 individuals and found to vary over the range of 2.4 to 3.9 X 10-6. By contrast, the molecular weight of low density lipoprotein measured on two separate occasions for specific individuals shows a mean difference of 0.07 X 10-6 and a standard deviation of 0.08 X 10-6; hence low density lipoprotein differing in molecular weight by greater than 0.2 X 10-6 may be considered different macomolecules. The distribution of the molecular weight of low density lipoprotein does not differ as a function of age or sex. Hyperlipemic subjects having monodisperse low density lipoprotein show similar molecular weight distribution to normal subjects, as do subjects with premature coronary artery disease. Family studies reveal a correlation coefficient of 0.82 between average molecular weights of parents and offspring, with significance at 0.01. In order to assess the influence of environment on molecular weight of low density lipoprotein, the correlation coefficient between the fathers' and mothers' low density lipoprotein was measured and no statistically significant correlation was found. These data are interpreted as strong evidence for a genetic determination of molecular weight of low density lipoprotein. A study of individuals in five families yields molecular weight data consistent with a single gene locus genetic mode of inheritance without dominance. The regression coefficient of the mean low denisty lipoprotein parental molecular weight on the offspring molecular weight is 0.30. If the variability of molecular weight is considered as an expression of phenotypic variance, then the regression analysis identified 30% of this phenotypic variance as arising from additive gene action presumably at a single locus. Segregation in the family data is consistent. Since the differences in molecular weight of low density lipoprotein arise from differences in the amount of lipid bound to the apoprotein, it is likely that an additional portion of the phenotypic variance of the molecular weight results from individual variations in the metabolism of low density lipoprotein, which yield differences in lipid content. The individual variation in molecular weight is only approximately 5%; hence those metabolic sequences that influence molecular weight of low density lipoproteins must be precisely controlled.