应用共聚焦显微镜对Alport综合征患者肾小球基底膜中IV型胶原亚链进行定量分析。

Quantitative analysis of type IV collagen subchains in the glomerular basement membrane of patients with Alport syndrome with confocal microscopy.

作者信息

Su Jian, Liu Zhi-Hong, Zeng Cai-Hong, Chen Hui-Ping, Li Lei-Shi

机构信息

Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China.

出版信息

Nephrol Dial Transplant. 2006 Jul;21(7):1838-47. doi: 10.1093/ndt/gfl090. Epub 2006 Mar 30.

DOI:10.1093/ndt/gfl090

PMID:16574687

Abstract

BACKGROUND

Alport syndrome (AS) is an inherited nephropathy characterized by glomerular basement membrane (GBM) abnormalities due to mutations in the type IV collagen genes. Through immunofluorescence analysis, the absence of alpha3(IV), alpha4(IV) and alpha5(IV) chains within the GBM has been shown in the majority of AS cases. In some atypical AS cases, however, staining of the GBM with antibodies against the alpha3(IV), alpha4(IV) and alpha5(IV) chains appeared normal. In this study, we studied these atypical AS cases by quantitative analysis of the expression of type IV collagen subchains in GBM.

METHODS

Twelve patients diagnosed with AS, yet having normal staining for alpha3(IV) and alpha5(IV) chains in the GBM, were recruited. Quantitative analysis of type IV collagen subchains in the GBM was performed using confocal microscopy and immunofluorescence double label techniques.

RESULTS

The absolute amounts of alpha3(IV), alpha4(IV) and alpha5(IV) were significantly lower in AS patients than that in normal subjects, associated with up-regulated expression of type IV collagen in GBM. It was found that eight cases had decreased ratios of alpha3(IV)/IV, alpha4(IV)/IV and alpha5(IV)/IV in the GBM simultaneously; one had reduced levels of alpha3(IV)/IV and alpha5(IV)/IV but had a normal level of alpha4(IV)/IV, and one had reduced alpha3(IV)/IV with normal alpha4(IV)/IV and alpha5(IV)/IV levels. The remaining two patients had normal ratios of alpha3(IV)/IV, alpha4(IV)/IV and alpha5(IV)/IV.

CONCLUSIONS

Confocal analysis demonstrated for the first time that the ratios of alpha3(IV)/IV, alpha4(IV)/IV and alpha5(IV)/IV in the GBM decreased in patients with AS, even though routine immunofluorescence staining for alpha(IV) chains appeared normal. This result not only sheds light on the pathogenesis of AS, but also provides an alternative approach to diagnose atypical AS cases.

摘要

背景

Alport综合征（AS）是一种遗传性肾病，其特征是由于IV型胶原基因突变导致肾小球基底膜（GBM）异常。通过免疫荧光分析，大多数AS病例显示GBM内缺乏α3（IV）、α4（IV）和α5（IV）链。然而，在一些非典型AS病例中，用抗α3（IV）、α4（IV）和α5（IV）链抗体对GBM进行染色显示正常。在本研究中，我们通过对GBM中IV型胶原亚链表达的定量分析来研究这些非典型AS病例。

方法

招募了12例被诊断为AS但GBM中α3（IV）和α5（IV）链染色正常的患者。使用共聚焦显微镜和免疫荧光双标记技术对GBM中的IV型胶原亚链进行定量分析。

结果

AS患者中α3（IV）、α4（IV）和α5（IV）的绝对量显著低于正常受试者，这与GBM中IV型胶原表达上调有关。发现8例患者GBM中α3（IV）/IV、α4（IV）/IV和α5（IV）/IV的比例同时降低；1例患者α3（IV）/IV和α5（IV）/IV水平降低，但α4（IV）/IV水平正常，1例患者α3（IV）/IV降低，α4（IV）/IV和α5（IV）/IV水平正常。其余2例患者α3（IV）/IV、α4（IV）/IV和α5（IV）/IV的比例正常。