Prakash M, Shetty J K, Dash S, Barik B K, Sarkar A, Prabhu R
Department of Biochemistry, Kasturba Medical College, Manipal, Karnataka, India.
Indian J Nephrol. 2008 Oct;18(4):150-4. doi: 10.4103/0971-4065.45289.
Although considered useful in the diagnosis and prognosis of renal diseases, proteinuria can only be detected after significant renal paranchymal changes. There is considerable interest in the estimation of urinary peptides as an early marker of renal disease. In the current study, we have estimated urinary peptides in patients with different grades of proteinuria. Twenty-four hour urine samples were collected from 138 subjects and classified into three groups based on the urine protein excreted: group I (normoproteinuria, 0-150 mg/day, n = 37), group II (microproteinuria, 150-300 mg/day, n = 31), and group III (macroproteinuria, > 300 mg/day, n = 70). Urine proteins were determined using Bradford's method and urinary peptide levels were determined by subtracting Bradford's value from the Lowry value of the same sample. There was a significant decrease in the levels of urinary peptides in group III compared to group I (P < 0.01), however, there was no difference in peptides between groups I and II. The percentage of urinary peptides was decreased in both groups II and III compared to group I (P < 0.01), and there was a significant difference in % urinary peptide content in group II compared to group III (P < 0.01). On correlation, % urinary peptides correlated negatively with urinary proteins/g creatinine (r = - 0.782, P < 0.01) and positively with urinary peptides/g creatinine (r = 0.238, P < 0.01). Our data suggest that there is a marked decrease in urinary peptide levels with an increase in proteinuria. This may suggest impaired tubular protein reabsorption and degradation capacity of renal tubules.
尽管蛋白尿在肾脏疾病的诊断和预后评估中被认为是有用的，但只有在肾脏实质发生显著变化后才能检测到。人们对尿肽作为肾脏疾病的早期标志物的评估有相当大的兴趣。在当前的研究中，我们对不同蛋白尿等级的患者的尿肽进行了评估。从138名受试者收集了24小时尿液样本，并根据尿蛋白排泄量分为三组：第一组（正常蛋白尿，0 - 150毫克/天，n = 37），第二组（微量蛋白尿，150 - 300毫克/天，n = 31），第三组（大量蛋白尿，> 300毫克/天，n = 70）。使用Bradford法测定尿蛋白，并通过从同一样本的Lowry值中减去Bradford值来测定尿肽水平。与第一组相比，第三组的尿肽水平显著降低（P < 0.01），然而，第一组和第二组之间的肽没有差异。与第一组相比，第二组和第三组的尿肽百分比均降低（P < 0.01），并且第二组与第三组的尿肽含量百分比存在显著差异（P < 0.01）。经相关性分析，尿肽百分比与尿蛋白/肌酐呈负相关（r = - 0.782，P < 0.01），与尿肽/肌酐呈正相关（r = 0.238，P < 0.01）。我们的数据表明，随着蛋白尿增加，尿肽水平显著降低。这可能提示肾小管蛋白重吸收和降解能力受损。
