Department of Internal Medicine IV (Nephrology and Hypertension), Medical University Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria.
Emergentec Biodevelopment GmbH, Vienna, Austria.
Nephrol Dial Transplant. 2016 Sep;31(9):1444-52. doi: 10.1093/ndt/gfv451. Epub 2016 Feb 3.
Human lifespan is increasing continuously and about one-third of the population >70 years of age suffers from chronic kidney disease. The pathophysiology of the loss of renal function with ageing is unclear.
We determined age-associated gene expression changes in zero-hour biopsies of deceased donor kidneys without laboratory signs of impaired renal function, defined as a last serum creatinine >0.96 mg/dL in females and >1.18 mg/dL in males, using microarray technology and the Significance Analysis of Microarrays routine. Expression changes of selected genes were confirmed by quantitative polymerase chain reaction and in situ hybridization and immunohistochemistry for localization of respective mRNA and protein. Functional aspects were examined in vitro.
Donors were classified into three age groups (<40, 40-59 and >59 years; Groups 1, 2 and 3, respectively). In Group 3 especially, genes encoding for metallothionein (MT) isoforms were more significantly expressed when compared with Group 1; localization studies revealed predominant staining in renal proximal tubular cells. RPTEC/TERT1 cells overexpressing MT2A were less susceptible towards cadmium chloride-induced cytotoxicity and hypoxia-induced apoptosis, both models for increased generation of reactive oxygen species.
Increased expression of MTs in the kidney with ageing might be a protective mechanism against increased oxidative stress, which is closely related to the ageing process. Our findings indicate that MTs are functionally involved in the pathophysiology of ageing-related processes.
人类的寿命在不断延长，约有三分之一的 70 岁以上人群患有慢性肾脏病。衰老导致肾功能丧失的病理生理学机制尚不清楚。
我们使用微阵列技术和 Significance Analysis of Microarrays 常规，确定了无实验室肾功能受损迹象的已故供体肾脏零时间活检中与年龄相关的基因表达变化，定义为女性最后血清肌酐>0.96mg/dL 和男性最后血清肌酐>1.18mg/dL。通过定量聚合酶链反应、原位杂交和免疫组织化学检测选定基因的表达变化，以确定各自的 mRNA 和蛋白质的定位。还在体外检查了功能方面。
供体被分为三组（<40 岁、40-59 岁和>59 岁；分别为组 1、2 和 3）。尤其是在第 3 组中，与第 1 组相比，编码金属硫蛋白（MT）同工型的基因表达更为显著；定位研究显示，在肾近端肾小管细胞中存在明显的染色。过表达 MT2A 的 RPTEC/TERT1 细胞对氯化镉诱导的细胞毒性和缺氧诱导的细胞凋亡的敏感性较低，这两种模型均与活性氧的产生增加有关。
随着年龄的增长，肾脏中 MT 的表达增加可能是一种对抗氧化应激增加的保护机制，而氧化应激与衰老过程密切相关。我们的发现表明，MT 参与了与衰老相关的病理生理过程。
