Poly(ADP-ribose) polymerase expression in kidney transplantation: from alfa (alpha) to Omega (Omega).

INTRODUCTION: Overactivation of the enzyme poly(ADP-ribose) polymerase (PARP-1) can be induced by ischemia-reperfusion and involved in the renal injury subsequent to kidney transplant. The poly(ADP-ribosy)lation mechanism alters free radical-induced DNA damage, which is repair by PARP-1 polymer. However, PARP-1 overexpression induces cellular necrosis. Our aim was to study the immunohistochemical PARP-1 expression in kidney transplant biopsies associated with various events. MATERIALS AND METHODS: We studied the nuclear expression of PARP-1 in kidney tubule cells by immunohistochemistry using the monoclonal antibody PAR01 in donor biopsies without acute tubular necrosis (ATN) (n = 60; controls), allografts that suffer ATN (n = 90) or an episode of acute humoral rejection (n = 12) or acute tubulointerstitial rejection (n = 25), or chronic allograft nephropathy (n = 25). Furthermore, we also studied protocol biopsies with subclinical rejection (n = 60). Renal lesions in transplant biopsies were graded blindly using 1997 Banff criteria without any clinical information. RESULTS: Biopsies without morphological features of ATN, namely acute tubulointerstitial rejection, borderline or subclinical rejection, showed lesser PARP-1 expression compared with biopsies with ATN or with ischemic mechanism of acute humoral rejection or chronic allograft nephropathys. We observed an inverse relation between PARP-1 expression and renal function (P < .001). Overall, renal biopsies showing ATN revealed greater expression of PARP-1 (r = 0.785, Pearson test). A significant relationship with PARP-1 expression was demonstrated with renal function (effective diuresis, serum creatinine levels) and pretransplant cold ischemia time (P < .001). CONCLUSION: Kidney transplant events including ischemia were associated with the highest PARP-1 expression and worse allograft renal function.

Role of poly-(ADP-ribose) polymerase in transplant acute tubular necrosis and its relationship with delayed renal function.

The enzyme poly(ADP-ribose) polymerase (PARP-1) participates in the repair of DNA damaged by genotoxic agents such as oxygen-derived free radicals. If the allograft suffers pretransplant cold ischemia and subsequent ischemia-reperfusion injury (IR), overactivation of PARP-1 can be induced, which may lead to an increase in acute tubular necrosis (ATN) and a delay in total recovery of renal function (RRF) of the transplanted organ. We studied the nuclear expression of PARP-1 in tubular cells by immunohistochemistry with the monoclonal antibody PAR01 in 104 kidney transplant biopsies from allografts with ATN. In 50% of biopsies with ATN, >50% of tubular nuclei were PARP-1+; only 9.6% of biopsies were negative. The increase in the immunohistochemical expression of PARP-1 showed a statistically significant relationship with the duration of cold ischemia, with serum creatinine levels, and with the time required to achieve effective diuresis (P < .0001, Spearman test). Cold ischemia of >24 hours and serum creatinine levels >1.7 mg/dL showed a statistically significant relationship with the highest PARP-1 expression levels (2.83 +/- 0.4 vs 1.36 +/- 0.8, P < .0001, Mann-Whitney U test). We conclude that PARP-1 plays an important role in ATN and RRF and is related to the extent and severity of ATN and to the renal allograft function.

Correlation of morphological findings with functional reserve in the aging donor: role of the poly (ADP-ribose) polymerase.

INTRODUCTION: The enzyme poly (ADP-ribose) polymerase (PARP-1) participates in the first events of DNA repair in higher organisms. Under conditions of tissue ischemia, this action can lead to significant decreases in NAD(+), massive adenosine triphosphate (ATP) depletion, and cell death. In renal grafts with pretransplantation cold ischemia and subsequent ischemia-reperfusion injury, overactivation of PARP-1 may lead to a higher index of acute tubular necrosis, a delay in total recovery of the function of the transplanted organ, and an early progression to chronic graft nephropathy. The present study examined whether increased tubular expression of PARP-1 in kidneys from aged donors contributed to recipient renal function. MATERIAL AND METHOD: We studied the nuclear expression of PARP-1 using immunohistochemistry with monoclonal antibody PAR01 in 75 kidney biopsy specimens from 40 aged donors. RESULTS: Immunohistochemical expression of PARP-1 showed a statistically significant relationship with donor age (r =.408, P =.006, Spearman test), with time required to achieve effective diuresis (r =.386, P =.01, Spearman test) and with creatinine levels in the first 3 months. We also highlighted a greater intensity of PARP-1 expression in suboptimal donor kidneys that failed to reduce the serum creatinine levels to <1.7 mg/dL (creatinine <1.7 PARP: 1.29 +/- 1.49 vs creatinine >1.7 PARP: 2.29 +/- 1.33, P =.047, Mann-Whitney U test). CONCLUSION: We conclude that the determination of PARP-1 in biopsy specimens from aged donors may be a useful predictive factor for renal graft function.