Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University School of Medicine, 010-8543 Akita, Japan.
Horm Metab Res. 2009 Dec;41(12):910-5. doi: 10.1055/s-0029-1233458. Epub 2009 Aug 7.
Previous studies of diabetic patients indicate that increased urinary excretion of certain plasma proteins (molecular radii <55 A), such as IgG, transferrin, and ceruloplasmin, precede the development of microalbuminuria. Moreover, increases in these urinary proteins predict future development of microalbuminuria. To clarify whether blood pressure changes influence urinary excretion of these proteins, we examined relationships between diurnal blood pressure changes measured by ambulatory blood pressure monitoring and urinary excretion of IgG, transferrin, ceruloplasmin, alpha2-macroglobulin (88 A) and albumin (36 A) measured separately during the day and night in 20 healthy controls and 26 normotensive, normoalbuminuric diabetic patients. Diurnal change in systolic blood pressure was not correlated to urinary excretion of either albumin or alpha2-macroglobulin in either diabetic patients or controls. However, statistically significant correlations between diurnal changes in systolic blood pressure and those of urinary excretion of IgG, transferrin and ceruloplasmin were found in diabetic patients but not in controls. The present findings suggest that urinary excretion of IgG, transferrin, and ceruloplasmin are more easily affected than albuminuria by systemic blood pressure changes in normoalbuminuric diabetic patients. This is supported by our previous finding that urinary excretion of IgG, transferrin and ceruloplasmin increased while albuminuria did not following enhanced glomerular filtration rate after acute protein loading, which causes increased glomerular capillary pressure due to afferent arterioles dilation, mimicking diabetic intra-renal hemodynamics. Taken together, these findings suggest that urinary excretion of IgG, transferrin, and ceruloplasmin may be more sensitive indicators of glomerular capillary pressure change than albuminuria in normoalbuminuric diabetic patients.
先前对糖尿病患者的研究表明，某些血浆蛋白（分子半径<55A）如 IgG、转铁蛋白和铜蓝蛋白的尿排泄增加先于微量白蛋白尿的发生。此外，这些尿蛋白的增加预示着微量白蛋白尿的未来发展。为了阐明血压变化是否影响这些蛋白质的尿排泄，我们检查了 20 名健康对照者和 26 名血压正常、尿白蛋白正常的糖尿病患者日间血压监测的日间血压变化与 IgG、转铁蛋白、铜蓝蛋白、α2-巨球蛋白（88A）和白蛋白（36A）的日间和夜间尿排泄之间的关系。在糖尿病患者和对照组中，日间收缩压的变化与白蛋白或α2-巨球蛋白的尿排泄均无相关性。然而，在糖尿病患者中发现日间收缩压变化与 IgG、转铁蛋白和铜蓝蛋白的尿排泄变化之间存在统计学上的显著相关性，但在对照组中则没有。这些发现表明，在尿白蛋白正常的糖尿病患者中，与白蛋白尿相比，系统性血压变化更容易影响 IgG、转铁蛋白和铜蓝蛋白的尿排泄。这与我们之前的发现一致，即当急性蛋白负荷导致肾小球滤过率增加时，由于入球小动脉扩张导致肾小球毛细血管压力增加，模拟糖尿病肾内血液动力学，IgG、转铁蛋白和铜蓝蛋白的尿排泄增加而白蛋白尿不增加。总之，这些发现表明，在尿白蛋白正常的糖尿病患者中，IgG、转铁蛋白和铜蓝蛋白的尿排泄可能比白蛋白尿更能敏感地反映肾小球毛细血管压力变化。
