Supplementary Material for: Serum Uromodulin Levels Reflect Severity of Clinicopathological Findings in Early Stage IgA Nephropathy

Introduction: Uromodulin (UMOD), also known as Tamm-Horsfall protein, is a kidney-specific protein. Recently, low levels of urinary UMOD (uUMOD) have been reported as a risk factor for renal function decline in IgA nephropathy (IgAN). However, the clinical significance of serum UMOD (sUMOD) is not clear. In this study, we clarified the clinical significance of sUMOD in IgAN. Methods: One hundred eight biopsy-proven IgAN patients were included in this study. The relationships between sUMOD levels and various clinicopathological findings were evaluated. Results: sUMOD was positively correlated with estimated glomerular filtration rate (eGFR) (p r = 0.5) and negatively correlated with creatinine (Cr) (p r = −0.51) and urinary protein (UP) (p = 0.005, r = −0.33). In the low sUMOD group (p 60 (n = 74), multivariate analyses revealed that low sUMOD independently predicted a 30% decline in eGFR and having severe histopathological changes. Conclusion: In IgAN, sUMOD levels were associated with renal function. Low sUMOD levels may be a risk factor for worsening renal function, especially in the early stage of IgAN.

研究背景：尿调蛋白（Uromodulin, UMOD）又称Tamm-Horsfall蛋白，是一种肾脏特异性蛋白。近期有研究报道，尿中尿调蛋白（uUMOD）水平降低是IgA肾病（IgA nephropathy, IgAN）患者肾功能下降的危险因素。然而，血清尿调蛋白（sUMOD）的临床意义目前尚未明确。本研究旨在明确IgAN患者血清尿调蛋白的临床意义。
研究方法：本研究共纳入108例经肾活检确诊的IgAN患者，分析了血清尿调蛋白水平与各项临床病理指标的相关性。
研究结果：血清尿调蛋白水平与估算肾小球滤过率（estimated glomerular filtration rate, eGFR）呈正相关（r=0.5，p<0.001），与肌酐（Cr）呈负相关（r=-0.51，p<0.001），与尿蛋白（UP）亦呈负相关（p=0.005，r=-0.33）。在低血清尿调蛋白组（阈值<60 mL·min⁻¹·1.73m⁻²，n=74）中，多因素分析显示，低血清尿调蛋白水平可独立预测eGFR下降30%的风险，以及存在严重肾脏病理改变。
研究结论：在IgAN患者中，血清尿调蛋白水平与肾功能密切相关。低血清尿调蛋白水平可能是肾功能恶化的危险因素，尤其在IgAN早期阶段。