Urinary Protein Excretion in the Rat: Strain and Age Dependence1

Despite growing evidence of sex differences in the progression of hypertension, there are no guidelines that differentiate treatment between men and women. Intrarenal renin-angiotensin system (RAS) activation and tissue injury in 2-kidney, 1-clip (2K1C) hypertensive rats have been characterized in previous studies of male but not female rats. To evaluate possible sex differences in response to renovascular hypertension, urinary angiotensinogen (uAGT) excretion, systolic blood pressure (BP), urinary protein excretion, and renal function were assessed in female rats.Female (n=8) and male (n=6) rats underwent placement of a 0.2 mm clip on the left renal artery to simulate unilateral renal artery stenosis. BP was measured by tail-cuff plethysmography, and clearance studies were conducted in anesthetized rats to assess renal function. Urine protein concentration was determined by pyrogallol red method. uAGT was measured by ELISA as an index of intrarenal RAS activity. Systolic BP increased from 120±1 to 176±8 mmHg, and urinary protein excretion reached 20.2±5.6 mg/day in female rats. Although uAGT excretion increased from 13.2±7.7 ng/day to 74.1±29.9 ng/day in female rats, male rats had a significantly higher uAGT excretion of 1572.6±750 ng/day. Nonclipped kidneys exhibited more uAGT excretion compared to clipped kidneys, consistent with previous findings in males. Although 2K1C female rats demonstrate significantly lower renal function than sham females, they show more preserved renal function than male rats. Female rats also demonstrate significantly lower increases in systolic BP and urinary protein excretion compared to male rats. The data support substantial sex-dependent differences in renal responses to unilateral renal artery stenosis. The results show substantial increases in systolic BP, uAGT, and urinary protein excretion and decreased renal function after renal artery clipping in females, but the magnitude of the changes is markedly lower than in males. Nonclipped kidneys of both sexes exhibit greater uAGT excretion than clipped kidneys. Notably, females show less augmentation of the intrarenal RAS compared to male rats in renovascular hypertension.

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Comparison of single spot urinary albumin-creatinine ratio with 24-hour urinary protein excretion in women with preeclampsia

International Journal of Reproduction Contraception Obstetrics and Gynecology ◽

10.18203/2320-1770.ijrcog20181931 ◽

2018 ◽

Vol 7 (5) ◽

pp. 1929

Author(s):

Indu Kaul ◽

Bawa Ram Bhagat ◽

Deepika Sharma ◽

Gagan Singh

Keyword(s):

Urine Sample ◽

Predictive Value ◽

Solute Concentration ◽

Urinary Protein Excretion ◽

Urinary Protein ◽

Creatinine Ratio ◽

Albumin Creatinine Ratio ◽

Single Spot ◽

Spot Urine ◽

Protein Excretion

Background: The measurement of albumin: creatinine ratio (ACR) in a spot urine sample avoids the influence of variation in urinary solute concentration and provides a more convenient and rapid method to assess protein excretion. The aim of this study was to evaluate urinary spot ACR as a new marker for proteinuria and to study its correlation and accuracy in comparison with 24-hour urinary protein.Methods: The prospective one-year study was conducted on 100 pregnant women, 18-40 years, >20 weeks gestation with a diagnosis of preeclampsia. A spot midstream urine sample was taken for detection of albuminuria by dipstick method. Another spot sample was taken for detection and calculation of spot ACR. The 24-hour urine collection was taken immediately afterward to evaluate 24-hour urinary protein excretion.Results: A positive linear relation exists between ACR and 24-hour urinary protein excretion The ROC revealed cut-off of 20.4 with 88.5% sensitivity, 75% specificity, 98.8% positive predictive value and 21.4% negative predictive value. Spot urinary ACR >20.4 correctly identified women having 24-hour urinary protein excretion in excess of 0.3 gm/DL.Conclusions: A strong correlation exists between single spot urinary ACR with 24-hour urinary protein excretion in women with preeclampsia.

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