Incipient diagnosis and noninvasive forecasts using urinary biomarkers are important for preventing diabetic kidney disease (DKD) progression, but they are also controversial. Previous studies have shown a potential relationship between urinary tubular biomarkers (UTBs) and traditional Chinese medicine (TCM) syndrome in patients with DKD. Thus, we further evaluated the clinical significance of combined detection of urinary biomarkers in noninvasively predicting the extent of renal damage in patients with early DKD with kidney qi deficiency syndrome, and preliminarily explored the potential biological link between UTBs and TCM syndrome in DKD. We categorized 92 patients with Type 2 diabetes mellitus into three groups as follows: 20 patients with normoalbuminuria, 50 patients with microalbuminuria, and 22 patients with macroalbuminuria. We found that, in all groups, 24 hr urinary albumin (24hUAlb) and urinary albumin-to-creatinine ratio (UACR) showed stepwise and significant increases. Urinary cystatin C (UCysC), urinary N-acetyl-β-d-glucosaminidase (UNAG), and urinary retinol-binding protein (URBP) synchronously increased gradually, consistent with the degree of albuminuria in all groups. Moreover, 24hUAlb and UACR were positively correlated with UCysC, UNAG, and URBP, respectively. In 72 patients with Type 2 DKD with albuminuria, a positive correlation was observed between UNAG and URBP, UCysC was also positively correlated with UNAG and URBP, respectively. Additionally, TCM syndrome distributional characteristics in all patients were consistent with clinical manifestations of kidney qi deficiency syndrome. Therefore, the combined detection of UCysC, UNAG, URBP, and UAlb may be used as a practical clinical technique to noninvasively forecast the extent of renal injury in patients with early Type 2 DKD with kidney qi deficiency syndrome. UTBs may be one of the biological bases of the specific TCM syndromes in DKD.
Background: Urinary excreton of low molecular weight proteins such as beta2-microglobulin and retinol binding protein (RBP), and enzymes such as N-acetyl-beta-D-glucosaminidase (NAG), may be useful as indicators of renal tubular dysfunction in diabetes mellitus.
Objective: To describe the profile of urinary protein and enzyme excretion in 240 Chinese patients with type 2 diabetes mellitus in Singapore.
Materials and Methodology: Cross-sectional study of consecutive patients presenting for follow-up at a Government primary care clinic. Information was obtained from interview, physical examination and laboratory analysis. Data analysis included descriptive statistics on urinary protein and enzyme excretion, comparison of unadjusted and adjusted means of these among patient subgroups, as well as correlation with control of diabetes and other clinical parameters.
Results: Albuminuria correlated with urine B2-microglobulin (r=0.34, p<0.01) and RBP (r=0.46,p<0.01). hypertensive patients had significantly higher mean urine albumin (geometric mean 15.13mg/gCr) and B2-microglobulin (363.18ug/gCr) levels compared to patients without hypertension (7.07mg/gCR; 219,20ug/gCr; p<0.05). Patients with complications of diabetes also had higher albumin (15.55 vs 6.20mg/gCr), B2-microglobulin (344.47 vs 288.83ug/gCr) and RBP excretion (152.02 vs 94.54mg/gCr). Two-hour postprandial sugar correlated with B2-microglobulin (r=0.33, p<0.01), RBP (r=0.35, p<0.01) and NAG (r=0.28, p<0.01). Urinary protein excretion did not correlate with HbA1c, fasting blood sugar, age of patient or duration since diagnosis.
Conclusion: These results among 240 Chinese patients in Singapore were consistent with reports from other study populations.