MOLECULAR MECHANISMS OF DELAYED KIDNEY GRAFT FUNCTION

D. Kentrup, S. Reuter, B. Edemir, A. Grabner, H. Pavenstädt, E. Schlatter, E. Büssemaker
Experimentelle Nephrologie, Medizinische Klinik Und Poliklinik D, Universitätsklinikum Münster, Münster/GERMANY

Body: Introduction: One of the main causes of acute renal failure following (renal) surgery, transplantation or trauma is renal ischemia-reperfusion injury (IRI). Due to the important role of cytoskeletal reorganization in these processes, mainly regulated by Rho GTPases, we hypothesized that blockade of the Rho effector Rho-associated coiled-coil containing protein kinase (ROCK) may improve renal IRI outcome. Since IRI triggers a complex cascade of events in the affected organ systems, involving an intricate network of several different pathways, microarray analysis provided a suitable analytical approach. Methods: Male Sprague Dawley rats were unilaterally nephrectomized one week before inducing IRI by clamping the left renal artery for 45 min. Rats were divided into two groups: One h before the ischemia procedure rats received either 10 mg/kg hydroxyfasudil (HF, i.p.) or vehicle (CTR, isotonic NaCl). During the reperfusion phase following the operation rats were housed for 1-4 d in metabolic cages; blood and urine samples were taken daily for analysis. Microarray analysis was performed on kidneys of both groups, which were harvested on post operative day 4, as well as on kidneys from unilaterally nephrectomized rats. Data are given as mean values ± SEM. Results: Rats treated with HF showed a significantly improved creatinine-clearance (HF: 0.54 ± 0.03 ml/min/100 g vs. CTR: 0.14 ± 0.02 ml/min/100 g, n=6, p < 0.01) as well as fractional Na⁺-excretion (HF: 0.23 ± 0.04 % vs. CTR: 0.64 ± 0.22 %, n=6, p < 0.01) when compared to sham treated controls. Microarray analysis showed that 1115 genes were differentially expressed after IRI compared to unilaterally nephrectomized rats. Functional annotation showed that, among others, genes related to cell-cell signaling (151 genes), cellular movement (144 genes), cell death (200 genes), inflammatory responses (123 genes) and immune cell trafficking (84 genes) were overrepresented. The changes in gene expression were significantly reduced by HF-treatment. Conclusion: Attenuation of renal IRI via hydroxyfasudil mediated ROCK-inhibition was paralleled by a reduced alteration of the gene expression profile. Therefore, ROCK-inhibition is a potential therapeutic target in renal IRI.

Disclosure: All authors have declared no conflicts of interest.