Objectives: The telomere (T) length, p21(WAF1/CIP1) and p27(Kip1) cyclin dependent kinase inhibitor (CDKI) genes are considered the markers of cell senescence and DNA damage. The aim of the study was to evaluate the influence of renal ischemia/reperfusion (I/R) on the value of abovementioned markers. Methods: 13 Macaque cynomolgus monkey kidneys were harvested and placed in Eurocollins solution. 9 kidneys were ex-vivo perfused with human blood and 4 kidneys were not perfused at all (control group). Tissue expression of p21(WAF1/CIP1) and p27(Kip1) was evaluated immunohistochemically and the T lengths were measured by southern blotting technique. Results: Significantly higher levels of p21 and p27 were expressed by the glomeruli (p=0.001 and 0.0001), tubules (p=0.0065 and 0.0006) and
interstitial cells (p=0.0017 and 0.0022, respectively) of the xenoperfused kidneys. The mean T length was higher in the control group (5.56±0.60 kbp) than in the study group kidneys (5.46±0.36 kbp) (P=NS). Conclusion: Renal I/R is associated with telomere shortening and an over-expression of p21 and p27 genes indicating substantial DNA damage and/or accelerated tissue senescence.