Djamali Arjang, Sadowski Elizabeth A, Muehrer Rebecca J, Reese Shannon, Smavatkul Chanigan, Vidyasagar Aparna, Fain Sean B, Lipscomb Ryan C, Hullett Debra H, Samaniego-Picota Millie, Grist Thomas M, Becker Bryan N
Department of Medicine, University of Wisconsin-Madison, Madison, WI 53713, USA.
Am J Physiol Renal Physiol. 2007 Feb;292(2):F513-22. doi: 10.1152/ajprenal.00222.2006. Epub 2006 Oct 24.
Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) uses deoxyhemoglobin as an endogenous contrast agent for the noninvasive assessment of tissue oxygen bioavailability. We hypothesized that intrarenal oxygenation was impaired in patients with chronic allograft nephropathy (CAN). Ten kidney-transplant recipients with CAN and nine healthy volunteers underwent BOLD-MRI. Medullary R2* (MR2*) and cortical R2* (CR2*) levels (measures directly proportional to tissue deoxyhemoglobin levels) were determined alongside urine and serum markers of oxidative stress (OS): hydrogen peroxide (H(2)O(2)), F(2)-isoprostanes, total nitric oxide (NO), heat shock protein 27 (HSP27), and total antioxidant property (TAOP). Mean MR2* and CR2* levels were significantly decreased in CAN (increased local oxyhemoglobin concentration) compared with healthy volunteers (20.7 +/- 1.6 vs. 23.1 +/- 1.8/s, P = 0.03 and 15.9 +/- 1.9 vs. 13.6 +/- 2.3/s, P = 0.05, respectively). There was a significant increase in serum and urine levels of H(2)O(2) and serum HSP27 levels in patients with CAN. Conversely, urine NO levels and TAOP were significantly increased in healthy volunteers. Multiple linear regression analyses showed a significant association between MR2* and CR2* levels and serum/urine biomarkers of OS. BOLD-MRI demonstrated significant changes in medullary and cortical oxygen bioavailability in allografts with CAN. These correlated with serum/urine biomarkers of OS, suggesting an association between intrarenal oxygenation and OS.
血氧水平依赖性功能磁共振成像（BOLD-MRI）使用脱氧血红蛋白作为内源性对比剂，用于无创评估组织氧生物利用度。我们假设慢性移植肾肾病（CAN）患者的肾内氧合受损。10例CAN肾移植受者和9名健康志愿者接受了BOLD-MRI检查。测定了髓质R2*（MR2*）和皮质R2*（CR2*）水平（与组织脱氧血红蛋白水平成正比的指标），同时检测了氧化应激（OS）的尿液和血清标志物：过氧化氢（H(2)O(2)）、F(2)-异前列腺素、总一氧化氮（NO）、热休克蛋白27（HSP27）和总抗氧化能力（TAOP）。与健康志愿者相比，CAN患者的平均MR2和CR2水平显著降低（局部氧合血红蛋白浓度升高）（分别为20.7±1.6对23.1±1.8/s，P = 0.03；15.9±1.9对13.6±2.3/s，P = 0.05）。CAN患者的血清和尿液H(2)O(2)水平及血清HSP27水平显著升高。相反，健康志愿者的尿液NO水平和TAOP显著升高。多元线性回归分析显示MR2和CR2水平与OS的血清/尿液生物标志物之间存在显著关联。BOLD-MRI显示CAN移植肾的髓质和皮质氧生物利用度有显著变化。这些变化与OS的血清/尿液生物标志物相关，提示肾内氧合与OS之间存在关联。
