ETHNIC DIFFERENCES IN RENAL FUNCTION IN AFRICAN AND CAUCASIANS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 与欧洲裔美国人相比，非洲裔美国人的高血压患病率和发病率更高，高血压并发症的发生率也更高，特别是中风和终末期肾脏疾病。此外，几项研究表明，非洲裔美国人的血压可能比欧洲裔美国人对钠缺乏或盐负荷更敏感。然而，研究人员并没有在正常血压和高血压参与者中或在女性和男性中始终观察到这种种族差异。在饮食方法阻止高血压(DASH)钠试验中，非裔美国人对饮食限制钠的反应比非非洲裔美国人更大，但只在对照饮食中，而不在DASH饮食中。我们随机招募南非黑人血统的核心家庭和比利时白人血统的核心家庭。我们测量了钠的排泄分数(FENA)，并通过清除内源性锂和肌酐估计了肾小管近端(RNaprox)和远端(RNadist)的钠重吸收分数。在多变量分析中，我们研究了RNaprox和RNadist与钠排泄分数(Fena)的关系，并估计了RNaprox和RNadist的遗传度。沿肾单位节段性钠重吸收是高度遗传性的，但近端小管和近端后小管的调节能力在白人和黑人之间是不同的。在过滤的钠负荷中，黑人参与者比白人参与者在近端肾单位重新吸收更多，而在近端后吸收较少。 在另一项研究中，研究了非洲家庭成员和无关的高加索人，调查了ABCB1基因及其周围的SNP与肾小球滤过率(GFR)的关系。2677T和3435T等位基因与肾小球滤过率显著升高相关，提示人类肾病的一个新的候选基因。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. African Americans, as compared to European Americans, have a higher prevalence and incidence of hypertension and experience higher rates of hypertensive complications  in particular, stroke and end-stage renal diseasel. Furthermore, several studies have suggested that blood pressure might be more sensitive to sodium depletion or salt loading in African Americans than in European Americans. However, researchers have not consistently observed this ethnic difference in normotensive and hypertensive participants or in women and men. In the Dietary Approaches to Stop Hypertension (DASH)  Sodium Trial, African Americans showed a greater blood pressure response to dietary sodium restriction than non-African Americans, but only on the control diet, and not on the DASH diet. We randomly recruited nuclear families of black South African ancestry and nuclear families of white Belgian ancestry. We measured the fractional excretion of sodium (FENa) and estimated the fractional renal sodium reabsorption in the proximal (RNaprox) and distal (RNadist) tubules from the clearances of endogenous lithium and creatinine. In multivariable analyses, we studied the relation of RNaprox and RNadist with the fractional excretion of sodium (FENa) and estimated the heritability of RNaprox and RNadist. Segmental sodium reabsorption along the nephron is highly heritable, but the capacity for regulation in the proximal and postproximal tubules differs between whites and blacks. Of the filtered sodium load, black participants reabsorb more than white participants in the proximal nephron and less postproximally. In another study, studying both African family members and unrelated Caucasions, SNPs in and around the ABCB1 gene were investigated for association with glomerular filtration rate (GFR). The 2677T and 3435T alleles were associated with significantly higher GFR, pointing to a new candidate gene for nephropathy in humans.