Péter Hardi

Effect of vitamin E on reperfusion injuries during reconstructive vascular operations on lower limbs.

INTRODUCTION The challenge against reperfusion injury and tissue oxidative stress, especially in vascular surgical interventions has an essential importance to reach the optimal clinical result. Numerous experimental attempts have proved the positive antioxidant effect of vitamin E in both chronic and acute phase models. In our study we monitored the effect of continuous preoperative treatment with vitamin E, on oxidative stress and tissue inflammation reactions developed after reconstructive operations. PATIENTS AND METHODS 32 patients have been involved in a randomized, prospective study, all suffering from AFS occlusion proved by angiography, and all undergone supragenual reconstruction. Duration of ischemia and amount of tissues under vascular clamping were almost the same in all patients. In the group treated with E-vitamin, we administered 1 x 200 mg of vitamin E p/o from the preoperative day till the 7th post operative day. Patients of the second group did not receive vitamin E. MATERIALS AND METHODS Peripheral blood samples were collected immediately before operation and at the end of the second reperfusion hour (early reperfusion period). Late reperfusion period has been monitored by analyzing blood samples taken at 24th hour and 7th day next to the operative ischemia. Among oxidative stress parameters, direct measurement of reactive oxygen intermediator (ROI) and determination of antioxidant state (GSH, Total-SH group, SOD) have been performed. Malondialdehyde was chosen as marker for lipidperoxidation. Inflammation reactions were monitored up on expression of adhesion molecules (CD11a and CD18). We also controlled the oscillation of myeloperoxidase (MPO) activity. RESULTS Our study has proved that preoperative (from the preoperative day till the 7th post operative day) administration of 200 mg vitamin E could reduce the level of oxidative stress developed after ischemic-reperfusion insult (lipidproxidation, antioxidant enzymes). According to our results, the prooxidant-antioxidant imbalance also diminished in the group with E-vitamin treatment. We proved that elective administration of vitamin E could decrease the WBC activity (MPO activity, free radicals production, expression of adhesion molecules) and its consequential local inflammation process, during early reperfusion.

Ischaemic postconditioning reduces serum and tubular TNF-α expression in ischaemic-reperfused kidney in healthy rats.

OBJECTIVE We studied the protective effects of postconditioning (PS) in healthy and hypercholesterolemic rats after renal ischaemia-reperfusion (IR) injury. We aimed to examine cytokine expression and apoptosis in tissue damage after revascularisation (TNF-α levels in serum and tissue). METHODS Male Wistar rats (n = 32) were divided into four groups. The animals of normal feed groups (NF) were fed with normal rat chow and the cholesterol feed groups (CF) were fed with 1.5% cholesterol containing diet for 8 weeks. Anaesthetized rats underwent a 45-min cross-clamping in both kidney pedicles. Ischaemia was followed by 120-min reperfusion with or without PS protocol (group PS vs. IR). Postconditioning was induced by four intermittent periods of ischaemia-reperfusion of 15-s duration each. Serum cholesterol, triglyceride, urea and creatinine levels were determined. Proinflammation was characterized by the measurement of serum TNF-α. Tissue injury in kidney was determined by formaline-fixed, paraffin-embedded tissue sections. Tissue TNF-α levels were determined by immunohistochemistry. RESULTS Significant elevation was observed in serum TNF-α level after IR injury in normal feed groups, which was reduced by PS. In CF group neither the elevation nor the postconditioning induced reduction were as significant as in the NF groups. In normal feed group PS caused a significant reduction in tissue TNF-α level which was significantly higher in CF. CONCLUSIONS Ischaemic postconditioning proved to be an effective defense against IR in NF groups, but it was ineffective in CF groups in kidney tissue.

Controlled reperfusion decreased reperfusion induced oxidative stress and evoked inflammatory response in experimental aortic-clamping animal model

UNLABELLED Revascularization after long term aortic ischaemia in vascular surgery induces reperfusion injury accompanied with oxidative stress and inflammatory responses. The hypothesis of this study was that the aortic occlusion followed by controlled reperfusion (CR) can reduce the ischaemia-reperfusion injury, the systemic and local inflammatory response induced by oxidative stress.Animal model was used. CONTROL GROUP animals underwent a 4-hour infrarenal aortic occlusion followed by continuous reperfusion. Treated group: animals were treated with CR: after a 4-hour infrarenal aortic occlusion we made CR for 30 minutes with the crystalloid reperfusion solution (blood: crystalloid solution ratio 1:1) on pressure 60 Hgmm. Blood samples were collected different times. The developing oxidative stress was detected by the plasma levels of malondialdehyde, reduced glutathion, thiol groups and superoxide dismutase. The inflammatory response was measured by phorbol myristate acetate-induced leukocyte reactive oxygen species production and detection of change in myeloperoxidase levels. The animals were anaesthetized one week after terminating ligation and biopsy was taken from quadriceps muscle and large parenchymal organs.CR significantly reduced the postischaemic oxydative stress and inflammatory responses in early reperfusion period. Pathophysiological results: The rate of affected muscle fibers by degeneration was significantly higher in the untreated animal group. The infiltration of leukocytes in muscle and parenchymal tissues was significantly lower in the treatedgroup.CR can improve outcome after acute lower-limb ischaemia. The results confirm that CR might be also a potential therapeutic approach in vascular surgery against reperfusion injury in acute limb ischaemia. Supported by OTKA K108596.

The role of GST polymorphism in reperfusion induced oxidative stress, inflammatory responses and clinical complications after surgical and percutaneous coronary intervention

BACKGROUND Patients having coronary artery disease treated by coronary bypass or PCI procedure are exposed to tissue damage because of the phenomenon called reperfusion injury. Reperfusion injury can be characterized/monitored by oxidative stress parameters, inflammatory markers and by post-operative complication rate. OBJECTIVE Beyond the obvious factors determining its severity (affected myocardial mass, ischaemic time, collateral circulation etc.) we examined the GST enzyme groups most cardio selective member, GSTP1 and its genetic polymorphism if there is any genetically determined preventive effect on the above-mentioned parameters. MATERIALS AND METHODES We have performed randomized prospective study in the Heart Institute of Pecs with 862 patients, treated by coronary bypass or PCI procedure. Blood samples were taken a day before, one hour, one day, one week after the operation. Leucocyte count (WBC), myeloperoxidase (MPO), thiol group (SH); Superoxide dismutase (SOD), malondialdehyde (MDA), reduced Glutathione (GSH) level was checked in different periods of time as a comparison. The onset of myocardial damage and the corresponding necro enzyme level changes were registered in the perioperative period. Our patients GSTP1 allele pair combinations (A, B, or C) were determined by real time PCR method. RESULTS In patients with GSTP1 AA genotype we have found significance level reaching plasma concentration rise in SOD and MDA, and drop in GSH, SH. The CKMB concentration rise in the post-operative 24 hours was significantly higher in the GSTP1 AA group. CONCLUSIONS According to our results the AA allele combination can be considered as a risk factor. GSTP1-AA allele pair has negative effect on ischemia-reperfusion tolerance of the heart. In case of cardiovascular interventions, the study of GST enzyme polymorphisms can be an independent risk stratification factor in determining the perioperative risk in the future.

Sodium Pentosan Polysulfate Reduced Renal Ischemia-Reperfusion-Induced Oxidative Stress and Inflammatory Responses in an Experimental Animal Model.

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.

Dilemmas of the reconstruction of the major pelvic artery due to infectious aortic graft complication

INTRODUCTION In the pelvic region thrombendarterectomy and bypass procedures are the most commonly performed procedures to treat peripheral artery occlusive diseases with chronic, severe circulation failure caused by atherosclerosis. Biologic and synthetic grafts can also be used in bypass surgeries. Application of synthetic grafts can acutely increase the development of the infectious graft complication and its mortality is still between 70 and 75% in pelvic processes. We describe the difficulties and dilemmas of an infectious aortobifemoral graft. CASE PRESENTATION 58-year-old female patient with right lower limb trophic ulcer underwent a DSA examination showing a bilateral iliac occlusion and aortobifemoral bypass surgery with Dacron graft implantation was performed. Re-occlusion and infection of the graft led to an in situ silver Dacron graft replacement. Due to the one-sided re-occlusion, a femoro-femoral crossover bypass surgery applying silver graft was performed. Despite the previously described procedures the infectious process got worse and autologous deep vein reconstruction was required beside the removal of the infectious synthetic grafts at the same time. DISCUSSION There are local and extraanatomical solutions to reduce infectious graft complication. In pelvic infections bypass surgeries using autologous deep vein can show the best results. This procedure is the trustworthiest but also the most straining technique due to the extension of surgical time and increased blood loss. The proper surgical strategy should be selected on individual bases including cardiopulmonary load ability, patient age and technical/infrastructural possibilities.

Histological and Mechanical Assessment of Decellularized Porcine Biografts, and Its Biological Evaluation following Aortic Implantation during Mid-Term Follow-Up

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.

Pentoxifylline attenuates the local and systemic inflammatory response after infrarenal abdominal aortic ischemia-reperfusion

AIMS We studied the new anti-inflammatory effects of non-specific phosphodiesterase (PDE) inhibitor pentoxifylline (PTX) on ischaemia-reperfusion injury and postconditioning of the lower extremities. We aimed to examine the oxidative stress parameters (OSP), the inflammatory response and the changes in structure of skeletal muscle after revascularization surgery. METHODS 50 Wistar rats in five groups underwent a 60 min infrarenal aortic cross clamping. After the ischaemia in IR+PC group ischemic postconditioning was performed, intermittent 15 seconds reperfusion, 15 seconds ischaemic periods were applied four times. The ischemic phase was followed by a 120 min of reperfusion. In IR+PTX group the animals were treated with PTX. In IR+PC+PTX group both ischemic postconditioning and PTX treatment were performed. Blood samples and biopsy from quadriceps muscle were collected. Plasma malondialdehyde, reduced glutathione, -SH-groups, TNF-alpha, IL-6 concentrations and superoxide dismutase enzyme activity were measured. RESULTS The levels of OSP and the inflammatory proteins were significantly higher in the IR group. PTX treatment and PC could significantly decrease the levels of OSP and inflammatory proteins. When the animals were co-treated with PTX and PC the results were even better. CONCLUSIONS Inhibition of PDE by PTX could markedly decrease the inflammatory response and moderate the ischaemia-reperfusion damages after lower limb ischemia and reperfusion. Administration of PTX could potentiate the beneficial effects of PC.

Cerebralis hyperperfusiós szindróma és vérnyomáskontroll

Absztrakt Bevezetes: A cerebralis hyperperfusios szindroma ritka, kevesse ismert korkep, amely azonban olykor sulyos kovetkezmenyekkel jarhat. Fellephet a carotis műteti revascularisatiojat vagy st...

Inhibition of Glutathione S-Transferase by Ethacrynic Acid Augments Ischemia-Reperfusion Damage and Apoptosis and Attenuates the Positive Effect of Ischemic Postconditioning in a Bilateral Acute Hindlimb Ischemia Rat Model

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.