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Acute kidney injury (AKI) remains an independent risk factor for mortality and morbidity after vascular surgery (affecting the renal arteries) or aortic surgery (requiring suprarenal aortic clamping). These types of vascular surgery produce renal ischemia/reperfusion (I/R) injury, a common cause of AKI. The present studies aimed at monitoring the course of renal I/R injury at the cellular level and investigating the efficacy of long-term preoperative and single-shot intraoperative administration of sodium pentosan polysulfate (PPS) to protect renal tissue from acute I/R injury both in native and diabetic kidneys in rats. Western blot analyses of the proapoptotic (bax) and antiapoptotic (bcl-2) signaling pathways, as well as the extent of DNA damage (phospho-p53), were performed. Oxidative stress followed upon the termination of malondialdehyde, reduced glutathione, thiol group, and superoxide dismutase plasma levels. Inflammatory changes were measured by the determination of serum tumor necrosis factor-α and interleukin-1 levels. Morphological changes were detected by histological examinations. Our results showed that the long-term administration of PPS has an advantage in reducing I/R kidney injury in diabetic rats, while high-dose, single-shot parenteral administration of PPS prior to revascularization might be useful in nondiabetic rats.

Aims: We studied the effects of the inhibition of the endogene antioxidant glutathione-S-transferase (GST) by ethacrynic acid (EA) on ischemia-reperfusion (IR) injury and postconditioning (PC) in the lower extremities. We aimed to examine the oxidative stress parameters (OSP), inflammatory response and activation of proapoptotic signaling proteins (PSP) after revascularization surgery. Methods: Sixty Wistar rats were divided into 6 groups: control, IR, PC, EA-control, IR and administration of EA (IR/EA) and PC and administration of EA (PC/EA). The IR, PC, IR/EA and PC/EA groups underwent 60 min of infrarenal aortic cross-clamping. After that, PC was performed in the PC and PC/EA groups. In 3 of the groups, the animals were treated with EA (EA-control, IR/EA and PC/EA groups) as well. The ischemia was followed by 120 min of reperfusion. Blood samples and biopsy specimens were collected from the quadriceps muscle. Plasma malondialdehyde, reduced glutathione, thiol/sulfhydryl group levels, TNF-α and IL-6 concentrations and superoxide-dismutase enzyme activity were measured. Results: The levels of the OSP and the inflammatory proteins were higher in the EA-administered groups. The ratio of phosphorylated PSP was higher in the EA-administered groups and the protective effect of PC did not develop. Conclusions: Inhibition of GST by EA augmented the IR damage. GST inhibition was associated with a different activation of the mitogen-activated protein kinases and the PSP, regulating these pathways in the process of apoptosis and PC.

Aims: Prosthetic graft infection frequently requires graft replacement. Among other options, a biological graft could serve as an alternative choice. Decellularization reduces tissue immunogenicity. Our aim was to determine an efficient decellularization method and to evaluate the decellularized porcine biografts’ adaptability. Methods: Four different protocols were implemented to decellularize porcine aortic segments (n = 4). Cell removal effectiveness and matrix structure preservation were histologically examined. Mechanical tests were performed. Decellularized porcine grafts were interpositioned in a porcine aorta. After a 6-month period, implanted samples were removed and evaluated using light and electron microscopy. Results: Histological results showed complete removal of cells and preserved connective tissue fiber structure following decellularization, using sodium dodecyl sulfate and sodium azide. Pressure tests demonstrated similar compliance to fresh vessels. In 9 out of 10 cases, pigs survived the follow-up period. Graft rejection, intimal hyperplasia, reocclusion and/or aneurysm formation were not observed. Presence of host cells and neoendothelialization were microscopically confirmed. Conclusions: This decellularization protocol enables a cost-effective preparation of biological grafts featuring reduced immunogenicity. The implanted grafts did not degenerate during the 6-month follow-up period, the lack of graft rejection suggests acceptable immunological tolerance, while recipient cells migrate into, proliferate and differentiate, thus creating the possibility for further use as an optional vascular graft.