STUDIES OF THE PATHOGENESIS OF GLOMERULOSCLEROSIS

大多数进展性肾小球疾病导致终末期肾脏疾病 系膜区细胞外基质(ECM)增多。 正常人和正常人外周血中细胞外基质蓄积的性质和速率的阐明 疾病状态是理解的先决条件，可能 干扰，进行性肾小球硬化。这就是理由所在 在正常科目中进行针对这些问题的详细研究 以及进行性肾小球疾病的患者。肾小球代表 一小部分肾皮质，我们发现在 它们的大小和基质合成是独立于其他 大脑皮层成分。因此，全肾制剂的变化会 不能准确反映肾小球内的情况。出于这些原因，我们 开发了一种包括原位肾小球显微剥离的技术 RT-RT和聚合酶链式反应(PCR)。定量检测IV型胶原基因表达的变化 我们建立了一种竞争性的聚合酶链式反应方法。该方法有一个级别 具有足够的灵敏度(0.01至0.1 attomole)以允许定量 在小鼠部分组织中表达的α-2IV胶原基因 肾小球。这使得我们能够开始研究人类肾小球 疾病。我们首先检查了为肾癌进行的肾切除手术， 因为这些患者中有近50%患有肾小球硬化。我们发现 α-2IV胶原基因在慢性阻塞性肺疾病患者中显著升高 肾小球硬化。细胞数量并没有平行增加， 这表明这种增加是由于α-2IV上调所致 胶原mRNA，而不是细胞增殖。正如我们在老鼠身上发现的那样， 肾小球α-2IV胶原基因水平保持较高水平，独立于 硬化的程度，即使在有广泛肾小球的患者 伤痕累累。令人满意的是，我们拥有适当的工具来检查 在人类肾脏疾病的发病机制方面，我们开始了多中心研究 合作开发进步的标志。在这第一阶段中 我们从肾脏中获得了cdna或分离的肾小球。 为诊断目的所做的活组织检查。最初的重点是糖尿病。 糖尿病和IgA肾病。我们的初步结果表明， 正常肾脏α-2/α-3IV型胶原比值为1。

Most progressive glomerular diseases leading to endstage renal disease have increased extracellular matrix (ECM) within mesangial areas. Elucidation of the nature and the rate of ECM accumulation in normal and diseased states are prerequisites for understanding, and possibly interfering with, progressive glomerulosclerosis. This was the rationale to undertake detailed studies addressing these issues in normal subjects and patients with progressive glomerular diseases. Glomeruli represent a small fraction of the renal cortex and we have found that changes in their size and matrix synthesis are regulated independently of other cortical elements. Therefore, changes in whole kidney preparations do not accurately reflect those in glomeruli. For these reasons we developed a technique consisting of microdissection of glomeruli, in situ RT of mRNA, and PCR. To quantitate changes in type IV collagen mRNA expression, we developed a competitive PCR assay. The method has a level of sensitivity (0.01 to 0.1 attomole) sufficient to allow quantitation of the alpha-2IV collagen cDNA expressed in a fraction of a mouse glomerulus. This allowed us to begin studies of human glomerular diseases. We first examined nephrectomies performed for renal carcinoma, since nearly 50% of these patients have glomerulosclerosis. We found that alpha-2IV collagen cDNA was significantly elevated in patients with glomerulosclerosis. There was not a parallel increase in cell number, suggesting that the increment was due to upregulation of alpha-2IV collagen mRNA, rather than cellular proliferation. As we found in mice, glomerular alpha-2IV collagen cDNA level remained high, independently of the degree of sclerosis, even in patients who had extensive glomerular scarring. Satisfied that we had the appropriate tools to examine the pathogenesis of renal disease in humans, we started a multi-center collaboration to develop markers of progression. During this first phase we obtained either cDNA or isolated microdissected glomeruli from renal biopsies done for diagnostic purposes. The initial focus is on diabetes mellitus and IgA nephropathy. Our preliminary results indicate that the alpha-2/alpha-3 type IV collagen ration is equal to 1 in normal kidneys.