Klammt Sebastian, Wojak Hans-Joachim, Mitzner Andrea, Koball Sebastian, Rychly Joachim, Reisinger Emil C, Mitzner Steffen
Division of Nephrology, Department of Medicine II, Medical Faculty of the University of Rostock, Rostock, Germany.
Nephrol Dial Transplant. 2012 Jun;27(6):2377-83. doi: 10.1093/ndt/gfr616. Epub 2011 Nov 15.
Albumin is an important transport protein for non-water-soluble protein-bound drugs and uraemic toxins. Its transport capacity is reduced in patients with advanced chronic kidney disease (CKD) and unbound fractions of uraemic toxins are related to complications of CKD. We investigated whether this reduction could be quantified and how it correlated with the stages of CKD. Albumin-binding capacity (ABiC) is a dye-based method that quantifies the remaining binding capacity of one major binding site (site II) of the albumin molecule.
Blood samples from 104 CKD patients were incubated with a binding site-specific fluorescent marker and the amount of unbound marker was determined by means of fluorescence detection after filtration. Measurements in a pooled human plasma were used for reference. Glomerular filtration rate and serum indoxyl sulphate (IS) levels were also determined.
Impairment of renal function was associated with a reduction in ABiC (mean ± SD: 118 ± 12; 111 ± 11; 99 ± 8 and 79 ± 9% for Stages 1/2, 3, 4 and 5, respectively; P < 0.001) and an increase in IS (3.9 ± 1.1; 6.2 ± 3.2; 16.3 ± 14.9 and 56.1 ± 28.6 μmol/L for Stages 1/2, 3, 4 and 5, respectively; P < 0.001). In dialysis patients, ABiC was lower in those with urine outputs <500 mL/day than in those with preserved urine output (73.7 ± 6.0 versus 83.8 ± 8.5%; P < 0.001).
Impaired albumin function in CKD patients can be quantified, is related to severity of kidney disease and is associated with an accumulation of uraemic albumin-bound retention solutes.
白蛋白是一种重要的转运蛋白，负责转运非水溶性的蛋白结合药物和尿毒症毒素。晚期慢性肾脏病（CKD）患者的白蛋白转运能力降低，尿毒症毒素的游离部分与CKD的并发症相关。我们研究了这种降低是否可以量化，以及它与CKD分期的相关性。白蛋白结合能力（ABiC）是一种基于染料的方法，用于量化白蛋白分子一个主要结合位点（位点II）的剩余结合能力。
将104例CKD患者的血样与一种位点特异性荧光标记物孵育，过滤后通过荧光检测法测定未结合标记物的量。采用混合人血浆测量结果作为对照。同时测定肾小球滤过率和血清硫酸吲哚酚（IS）水平。
肾功能损害与ABiC降低相关（1/2期、3期、4期和5期的平均值±标准差分别为118±12、111±11、99±8和79±9%；P<0.001），与IS升高相关（1/2期、3期、4期和5期的IS水平分别为3.9±1.1、6.2±3.2、16.3±14.9和56.1±28.6 μmol/L；P<0.001）。在透析患者中，尿量<500 mL/天的患者ABiC低于尿量正常的患者（73.7±6.0%对83.8±8.5%；P<0.001）。
CKD患者白蛋白功能受损可以量化，与肾脏疾病的严重程度相关，并且与尿毒症白蛋白结合潴留溶质的蓄积有关。
