Excretions of urinary albumin and various proteins increase in hypertension.

AIMS

Hypertension causes proteinuria and is an important factor in the progress of renal dysfunction. Increases in various proteins in urine are caused by malfunction of the glomerulus and the renal tubules. In the present study, the effects of hypertension on urinary excretion levels of various proteins were investigated to show the tubular cell malfunction in hypertensive patients.

METHODS AND SUBJECTS

The subjects included 55 non-diabetic hypertensive patients without previous treatment and 42 normotensive individuals without microalbuminuria. Total urinary protein/creatinine ratio was measured, and urinary proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

FINDINGS

Total urinary protein/creatinine ratio was higher in hypertensive patients than in normotensive individuals (122.0+/-11.0 vs. 60.6+/-3.1 mg/gCr; p<0.001). SDS-PAGE resolved 15 protein fractions from the urine of both groups. Thirteen fractions were more intensely stained in samples from the hypertensive than from the normotensive. Two fractions did not differ between the groups. Hypertension increased the urinary excretion of various proteins including proteins of less than 40 kDa, called tubular proteins, in addition to albumin.

CONCLUSIONS

Hypertension differently influenced the excretion of each urinary protein fraction. Tubular malfunction should be considered in hypertensive patients in addition to glomerular malfunction.