尿去分化足细胞作为狼疮肾炎的一种非侵入性生物标志物。

Urinary dedifferentiated podocytes as a non-invasive biomarker of lupus nephritis.

机构信息

Genotyping and Genetic Diagnosis Unit, INCLIVA Biomedical Research Institute, Avd. Menéndez Pelayo, acceso 4, 46010 Valencia, Spain Cardiometabolic and Renal Unit, INCLIVA Biomedical Research Institute, Avd. Menéndez Pelayo, acceso 4, 46010 Valencia, Spain.

Cardiometabolic and Renal Unit, INCLIVA Biomedical Research Institute, Avd. Menéndez Pelayo, acceso 4, 46010 Valencia, Spain CIBER Physiopathology of Obesity and Nutrition (CIBEROBN), Institute of Health Carlos III, Minister of Health, Madrid, Spain.

出版信息

Nephrol Dial Transplant. 2016 May;31(5):780-9. doi: 10.1093/ndt/gfw002. Epub 2016 Feb 29.

DOI:10.1093/ndt/gfw002

PMID:26932688

Abstract

BACKGROUND

Currently, renal biopsy remains the gold standard for the diagnosis and prognosis of lupus nephritis (LN). However, it is an invasive method, and new non-invasive laboratory tests are needed to identify renal involvement without renal biopsy. Podocyte damage plays an important role in the pathogenesis and progression of systemic lupus erythematosus (SLE). We characterize whether the phenotype of urinary podocytes (viability, apoptosis, mRNA and protein levels of the podocyte-associated molecules) is a novel marker of clinical and histological features in SLE patients with or without LN.

METHODS

We quantified in urinary sediments of 32 SLE patients and 20 controls, mRNA and protein levels of podocalyxin, synapotopodin, podocin, nephrin and WT-1 by quantitative real-time polymerase chain reaction and western blot analysis and correlated these with clinical and histological parameters. The viability of detached urine podocytes was analysed by flow cytometry with podocalyxin and annexin V/7-AAD double staining and immunofluorescence of urine podocyte cultures.

RESULTS

The degree of a poptotic podocytes from urine samples was significantly decreased in patients with LN, especially in the active state (33% compared with 75% in controls, P < 0.001), and the majority of the detached podocytes in the urine of patients with active LN were viable (70% grew in culture). Furthermore, urinary mRNA of podocyte-associated molecules was significantly lower in patients with active LN (P < 0.05) compared with healthy controls, and protein levels of podocyte markers were significantly increased in SLE patients, especially with LN compared with SLE without LN (P < 0.05) and the healthy control group (P < 0.01). Finally, urinary protein levels of podocyte-related markers were associated with proteinuria and histological features (P < 0.05 and P < 0.01), and receiver operating characteristics curves of protein levels discriminate between LN and healthy controls with an area under the curve (AUC) between 0.91 and 0.77 (P < 0.001).

CONCLUSIONS

Urinary dedifferentiated podocytes were shown in active LN, and their protein levels correlated with proteinuria and histological features in LN. These preliminary results suggest that it could be a potentially useful non-invasive marker for evaluating the progression of glomerular disease in SLE.

摘要

背景

目前，肾活检仍然是狼疮肾炎（LN）诊断和预后的金标准。然而，它是一种有创的方法，需要新的非侵入性实验室检测方法来识别肾活检无肾受累的情况。足细胞损伤在系统性红斑狼疮（SLE）的发病机制和进展中起着重要作用。我们描述了尿足细胞的表型（活力、凋亡、足细胞相关分子的 mRNA 和蛋白水平）是否是 LN 患者和非 LN 患者的临床和组织学特征的新型标志物。

方法

我们通过实时定量聚合酶链反应和 Western blot 分析，对 32 例 SLE 患者和 20 例对照者的尿液沉淀物进行了足细胞相关分子（podocalyxin、synaptopodin、podocin、nephrin 和 WT-1）的 mRNA 和蛋白水平的定量分析，并将这些结果与临床和组织学参数相关联。通过用 podocalyxin 和 annexin V/7-AAD 双重染色以及尿足细胞培养物的免疫荧光法，分析脱落尿足细胞的活力。

结果

LN 患者尿样中的凋亡足细胞数量明显减少，尤其是在活动状态下（与对照组相比为 33%，P<0.001），而活动期 LN 患者尿液中的大部分脱落足细胞是存活的（70%在培养中生长）。此外，活动期 LN 患者的尿足细胞相关分子的 mRNA 水平明显低于健康对照组（P<0.05），SLE 患者的足细胞标志物蛋白水平明显升高，尤其是 LN 患者与无 LN 的 SLE 患者（P<0.05）和健康对照组（P<0.01）相比。最后，尿足细胞相关标志物的蛋白水平与蛋白尿和组织学特征相关（P<0.05 和 P<0.01），蛋白水平的受试者工作特征曲线以曲线下面积（AUC）在 0.91 到 0.77 之间区分 LN 与健康对照组（P<0.001）。