New computational fluid dynamics-based method for morphological and functional assessment in cardiovascular skill training.

Objective: During cardiovascular surgical skill training, the direct quantification regarding surgical performance is still lacking, including transferring clinically relevant information. Methods: We introduced a novel computational fluid dynamics-based method in support of vascular surgical hands-on training, which applies continuous self-assessment in vascular anastomoses. The validation of the methodology was implemented in comparing with conventional training courses. Results: The fifth and seventh consecutive anastomoses of the experimental group showed significantly improved results regarding anastomosis quality when compared with the control group. Conclusions: Consecutive demonstration of three-dimensional morphology and functional assessment of anastomoses results in improved practical performance among learners regarding anastomosis quality.

Heterogeneous Maturation of Arterio-Venous Fistulas and Loop-Shaped Venous Interposition Grafts: A Histological and 3D Flow Simulation Comparison.

Vascular graft maturation is associated with blood flow characteristics, such as velocity, pressure, vorticity, and wall shear stress (WSS). Many studies examined these factors separately. We aimed to examine the remodeling of arterio-venous fistulas (AVFs) and loop-shaped venous interposition grafts, together with 3D flow simulation. Thirty male Wistar rats were randomly and equally divided into sham-operated, AVF, and loop-shaped venous graft (Loop) groups, using the femoral and superficial inferior epigastric vessels for anastomoses. Five weeks after surgery, the vessels were removed for histological evaluation, or plastic castings were made and scanned for 3D flow simulation. Remodeling of AVF and looped grafts was complete in 5 weeks. Histology showed heterogeneous morphology depending on the distribution of intraluminal pressure and WSS. In the Loop group, an asymmetrical WSS distribution coincided with the intima hyperplasia spots. The tunica media was enlarged only when both pressure and WSS were high. The 3D flow simulation correlated with the histological findings, identifying "hotspots" for intimal hyperplasia formation, suggesting a predictive value. These observations can be useful for microvascular research and for quality control in microsurgical training.

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 group's 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 patient's 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.

[New approach in the surgical treatment of mitral regurgitation: beating heart transapical neochord implantation]. / A mitralis elégtelenség sebészi kezelésének új megközelítése: transapicalis ínhúrpótlás dobogó szíven.

Severe mitral regurgitation due to prolapse of the valve demands early surgical intervention. Recently artificial chord implantation is the prefered solution, which requires cardioplegia and application of cardiopulmonary bypass using the left atrial approach. Transoesophageal echocardiography guided transapical neochord implantation is an emerging new technique for the treatment of mitral regurgitation. It enables the operation through left minithoracotomy on beating heart using a special instrument introduced into the left ventricle. Acute procedural success rates in different centres vary between 86 and 100%. According to reports, 92% of the patients do not require additional intervention at the 3-month follow-up. Continuous integration of data resulting improved outcomes supports the hope that this novel, less-invasive technique will be applied widely for the treatment of mitral regurgitation.

Polymorphisms in glutathione S-transferase are risk factors for perioperative acute myocardial infarction after cardiac surgery: a preliminary study.

In the present study we explored glutathione S-transferase (GST) polymorphisms in selected patients who experienced accelerated myocardial injury following open heart surgery and compared these to a control group of patients without postoperative complications. 758 Patients were enrolled from which 132 patients were selected to genotype analysis according to exclusion criteria. Patients were divided into the following groups: Group I: control patients (n = 78) without and Group II.: study patients (n = 54) with evidence of perioperative myocardial infarction. Genotyping for GSTP1 A (Ile105Ile/Ala113Ala), B (Ile105Val/Ala113Ala) and C (Ile105Val/Ala113Val) alleles was performed by using real-time-PCR. The heterozygous AC allele was nearly three times elevated (18.5 vs. 7.7 %) in the patients who suffered postoperative myocardial infarction compared to controls. Contrary, we found allele frequency of 14.1 % for homozygous BB allele in the control group whereas no such allele combination was present in the study group. These preliminary results may suggest the protective role for the B and C alleles during myocardial oxidative stress whereas the A allele may represent predisposing risk for cellular injury in patients undergoing cardiac surgery.

The role of the inhibition of glutathione-S-transferase in the protective mechanisms of ischemic postconditioning.

The antioxidant glutathione-S-transferase (GST) is a crucial determinant of the development of ischaemic-reperfusion (I/R) injury, and plays a pivotal role in the regulation of the mitogen activated protein kinase (MAPK) pathways involved in stress response and apoptosis. The aim of this study was to investigate whether inhibition of GST can abolish the benefit of ischaemic postconditioning (IPoC). A neonatal rat cardiomyocyte cell culture was prepared and divided into 6 groups: (I) control group without treatment; (II) cells exposed to simulated I/R; (III) simulated I/R (sI/R) with IPoC; (IV) ethacrynic acid (EA) alone; (V) sI/R with EA; and (VI) sI/R and IPoC together with EA. Viability of the cells was measured by MTT assay, the quantity of apoptotic cells was assessed by flow cytometry following annexin V-FITC - propidium-iodide double staining. The activation of JNK, p38, ERK/p42-p44 MAPKs, and GSK-3ß protein kinase was determined by flow-cytometric assay. GST inhibition markedly increased the apoptosis and decreased the cell viability despite IPoC. The protective effect of IPoC was lost in GST-inhibited groups for all MAPKs and GSK-3ß. GST activity is required for the survival of cultured cardiomyocytes under stress conditions. GST inhibition was associated with differential activation of MAP and the protein kinases regulating these pathways in the process of ischaemic postconditioning.

Protective effect of PACAP against doxorubicin-induced cell death in cardiomyocyte culture.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a widely distributed endogenous neuropeptide, also occurring in the cardiovascular system. Among others, PACAP has been suggested as a cardioprotective factor. It has been shown that PACAP inhibits cardiac fibrosis and protects cardiomyocytes against oxidative stress and in vitro ischemia/reperfusion. The aim of the present study was to investigate whether PACAP is protective in doxorubicin-induced cell death of cardiomyocytes. Cardiomyocytes were exposed to 1 µM doxorubicin for 24 h, which resulted in a marked reduction of cell viability and a parallel increase of apoptotic cells assessed by MTT test and annexin V/propidium iodide flow cytometry assay. Co-incubation with 20 nM PACAP increased cell viability and reduced the percentage of apoptotic cells. Furthermore, doxorubicin increased the activation of caspase-3 and decreased the phosphorylation of Bad, while simultaneous PACAP treatment reduced the caspase-3 activation and increased the level of phospho-Bad. In summary, our present results demonstrate that PACAP effectively protects cardiomyocytes against doxorubicin-induced apoptotic cell death.

PACAP ameliorates oxidative stress in the chicken inner ear: an in vitro study.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a pleiotropic and multifunctional neuropeptide. Numerous studies prove that PACAP has neuroprotective effects in diverse neuronal systems in vitro and in vivo. The involvement of PACAP in visual and olfactory sensory processing has also been documented, but little is known about its effects in the auditory system. The presence of PACAP and its receptor, the specific PAC1 receptor, has been shown in the cochlea and in brain structures involved in auditory pathways. The aim of the present study was to investigate whether PACAP is protective in cochlear oxidative stress-induced cell death, which is known to play a role in several ototoxic insults. Chicken cochlear cells were exposed to 1mM H(2)O(2), which resulted in a marked reduction of cell viability and a parallel increase of apoptotic and necrotic cells assessed by MTT test, annexin V/propidium iodide flow cytometry and JC-1 apoptosis assay. Co-incubation with 100nM PACAP increased cell viability and reduced the percentage of apoptotic cells. Furthermore, oxidative stress increased the activation of caspase-3, while simultaneous PACAP treatment reduced it. In summary, our present results demonstrate that PACAP effectively protects cochlear cells against oxidative stress-induced apoptotic cell death.

Cardioprotective action of urocortin in early pre- and postconditioning.

Pre- and postconditioning are powerful endogenous adaptive phenomenon of the organism whereby different stimuli enhance the tolerance against various types of stress. Urocortin (Ucn), member of the corticotropin-releasing factor (CRF) family has potent effects on the cardiovascular system. The aim of this article was to investigate the action of Ucn on cultured cardiomyocytes in the process of pre- and postconditioning. Isolated neonatal rat ventricular myocytes were preconditioned with adenosine, simulated ischemia, and Ucn (10-min treatment followed by 10-min reperfusion/recovery). For detecting the effect of alternative types of preconditioning, necrosis enzyme (lactate dehydrogenase [LDH]) release, vital staining (trypan blue), and ratio of apoptosis/necrosis were examined after cardiac cells were exposed to 3-h sustained ischemia and 2-h reperfusion. Same parameters were measured in the postconditioned groups (30- or 60-min ischemia followed by postconditioning with 10-min ischemic stimulus or Ucn and 2-h reperfusion). Cells exposed to 3-h ischemia followed by 2-h reperfusion were shown as control. Our results show that LDH release a number of trypan blue-stained dead cells and the ratio of apoptotized and necrotized cells was decreased in all preconditioned groups compared with control group. In postconditioned groups LDH content of culture medium, trypan blue-positive cardiomyocytes, and the rate of apoptotic/necrotic cells was reduced contrasted with non-postconditioned group. We can conclude that preconditioning with Ucn induced such a powerful cell protective effect as adenosine and ischemia. Furthermore, postconditioning with Ucn after 60-min ischemia was more cardioprotective than ischemic postconditioning.

Expression and protective role of heme oxygenase-1 in delayed myocardial preconditioning.

In the study the authors aimed to demonstrate the expression and protective effect of heme oxygenase-1 (HO-1) in the delayed preconditioning (PC) on cultured myocardiac cells. Neonatal rat cardiac myocytes were exposed to ischemic (ischemic medium [IM] for 20 min) and pharmacological (adenosine, epinephrine, opioid) PC. Twenty-four hours later cells were subjected to a simulated ischemia (SI)--culturing for 3 h in IM, followed by 2-h reperfusion in normal medium--and then lactate dehydrogenase (LDH), live/death ratio, and apoptosis were measured. For demonstrating the protective role of HO-1, its enzymatic activity was competitively inhibited by administration of zinc protoporphyrin IX (ZnPPIX), and HO-1 synthesis was blocked with HO-1 siRNA. Cells in control group were cultured under normoxic conditions. In SI group, cells underwent only an SI without PC. HO-1 expression in all of the groups was demonstrated with immunostaining. Our results showed a significant decrease of LDH release, apoptosis, and cell death in PC groups versus SI group, which has been risen in ZnPPIX- and HO-1 siRNA-treated groups. HO-1 immunostaining showed an appreciable HO-1 expression in PC groups, which was abolished with HO-1 siRNA administration, but not in ZnPPIX group. The results therefore suggest that HO-1 expression increases in both ischemic and pharmacological PC, and HO-1 has cellular protective effect against cell death and apoptosis in ischemia-reperfusion-induced oxidative injury.

Hyperosmotic stress-induced apoptotic signaling pathways in chondrocytes.

Articular chondrocytes have a well-developed osmoregulatory system that enables cells to survive in a constantly changing osmotic environment. However, osmotic loading exceeding that occurring under physiological conditions severely compromises chondrocyte function and leads to degenerative changes. The aim of the present study was to investigate the form of cell death and changes in apoptotic signaling pathways under hyperosmotic stress using a primary chondrocyte culture. Cell viability and apoptosis assays performed with annexin V and propidium iodide staining showed that a highly hyperosmotic medium (600 mOsm) severely reduced chondrocyte viability and led mainly to apoptotic cell death, while elevating osmotic pressure within the physiological range caused no changes compared to isosmotic conditions. Western blot analysis revealed that a 600 mOsm hyperosmotic environment induced the activation of proapoptotic members of the mitogen-activated protein kinase family such as c-Jun N-terminal kinase (JNK) and p38, and led to an increased level of extracellular signal regulated kinase (ERK1/2). Hyperosmotic stress also induced the activation of caspase-3. In summary, our results show that hyperosmotic stress leads to mainly apoptotic cell death via the involvement of proapoptotic signaling pathways in a primary chondrocyte culture.

Induction of necrotic cell death and mitochondrial permeabilization by heme binding protein 2/SOUL.

We found that heme-binding protein 2/SOUL sensitised NIH3T3 cells to cell death induced by A23187 and etoposide, but it did not affect reactive oxygen species formation. In the presence of sub-threshold calcium, recombinant SOUL provoked mitochondrial permeability transition (mPT) in vitro that was inhibited by cyclosporine A (CsA). This effect was verified in vivo by monitoring the dissipation of mitochondrial membrane potential. Flow cytometry analysis showed that SOUL promoted necrotic death in A23187 and etoposide treated cells, which effect was prevented by CsA. These data suggest that besides its heme-binding properties SOUL promotes necrotic cell death by inducing mPT.

Evaluation of oxidative stress in the thrombolysis of pulmonary embolism.

BACKGROUND: To analyse leukocyte function parameters and oxidative stress (OS) in patients with acute pulmonary embolism (PE) treated with thrombolytics. METHODS: Fifteen patients undergoing thrombolysis (TL) with ultra-high dose streptokinase (n = 8), or alteplase (tPA) (n = 7) treatment were studied. Blood samples were collected prior to TL, and then 8 h, 1, 3, 5 and 30 days after treatment. Malondialdehyde (MDA), reduced glutathione (GSH), plasma protein sulfhydryl groups (PSH) levels, superoxide dismutase (SOD) and myeloperoxidase enzyme (MPO) activities were measured in plasma or whole blood for monitoring of the OS markers. Production of reactive oxygen species (ROS) in whole blood was measured by luminol dependent chemiluminescence. Flow cytometry was used to determine CD11a, CD18, and CD97 surface antigen expression on leukocytes. RESULTS: The elevated MDA, ROS and MPO, decreased GSH and PSH levels indicated the presence of OS in patients with PE. MDA significantly (P < 0.05) increased, GSH significantly (P < 0.05) decreased following thrombolysis. ROS production peaked on the 3rd and 5th days. TL was accompanied by significant decrease in granulocyte and monocyte CD11a and CD18 as well as in granulocyte CD97 expression (P < 0.05). CONCLUSION: PE led to OS that was augmented following TL. Decreased adhesion molecule expression of circulating leukocytes in the early phase of TL reflects the pathological leukocyte endothelial cell interactions.

The neuroprotective effects of PACAP in monosodium glutamate-induced retinal lesion involve inhibition of proapoptotic signaling pathways.

Pituitary adenylate cyclase activating polypeptide (PACAP) and its receptors are present in the retina and exert several distinct functions. PACAP has well-known neuroprotective effects in neuronal cultures in vitro and against different insults in vivo. Recently we have shown that PACAP is neuroprotective against monosodium glutamate (MSG)-induced retinal degeneration. In the present study we investigated the possible signal transduction pathways involved in the protective effect of intravitreal PACAP administration against apoptotic retinal degeneration induced by neonatal MSG treatment. MSG induced activation of proapoptotic signaling proteins and reduced the levels of antiapoptotic molecules in neonatal retinas. Co-treatment with PACAP attenuated the MSG-induced activation of caspase-3 and JNK, inhibited the MSG-induced cytosolic translocation of apoptosis inducing factor (AIF) and cytochrome c, and increased the level of phospho-Bad. Furthermore, PACAP treatment alone decreased cytosolic AIF and cytochrome c levels, while PACAP6-38 increased cytochrome c release, caspase-3 and JNK activity and decreased phospho-Bad activity. In summary, our results show that PACAP treatment attenuated the MSG-induced changes in apoptotic signaling molecules in vivo and suggest that also endogenously present PACAP has neuroprotective effects. These results may have further clinical implications in reducing glutamate-induced excitotoxicity in several ophthalmic diseases.

PACAP inhibits oxidative stress-induced activation of MAP kinase-dependent apoptotic pathway in cultured cardiomyocytes.

The present article investigated the effect of pituitary adenylate cyclase-activating polypeptide (PACAP) on oxidative stress-induced apoptosis in neonatal rat cardiomyocytes. Our results show that PACAP decreased the ratio of apoptotic cells following H2O2 treatment. PACAP also diminished the activity of apoptosis signal-regulating kinase. These effects of PACAP were counteracted by the PACAP antagonist PACAP6-38. In summary, our results show that PACAP is able to attenuate oxidative stress-induced cardiomyocyte apoptosis and suggest that its cardioprotective effect is mediated through inhibition of the MAP kinase-dependent apoptotic pathway.

Involvement of ERK and CREB signaling pathways in the protective effect of PACAP in monosodium glutamate-induced retinal lesion.

Pituitary adenylate cyclase-activating polypeptide (PACAP) has well-documented neuroprotective actions, which have also been shown in retinal degeneration induced by monosodium glutamate (MSG) in neonatal rats. The aim of this article was to investigate the activation of extracellular signal-regulated kinase (ERK1/2) and cyclic adenosine 3',5'-phosphate (cAMP)-responsive element binding protein (CREB) signaling pathways by Western blot analysis in retinal degeneration induced by MSG. We found that intravitreal administration of PACAP preceding the MSG treatments induced significant increases in the phosphorylation, that is, the activation of ERK1/2 and its downstream target, CREB, 12 h after the treatment compared to the contralateral untreated eye during the first two treatments, with no further elevations 24 h after treatments. These results demonstrate that the degenerative effect of MSG and the protective effect of PACAP involve complex kinase signaling pathways and are related to cAMP/ERK/CREB activation.

Pathological circumstances impair the ability of "dark" neurons to undergo spontaneous recovery.

The effects of dehydrating drugs (furosemide, mannitol and glycerine), potassium channel modulators (tetraethylammonium chloride, 5-hydroxydecanoic acid Na salt, minoxidil and pinacidil), sodium channel modulators (veratridine, brevetoxin-9, 5-(N,N-dimethyl)amiloride and benzamil-HCl) and mitochondrial enzyme inhibitors (3-nitropropionic acid, 2,4-dinitrophenol and chloramphenicol) on the fate of electrically produced "dark" hippocampal dentate granule neurons were investigated. All but one (chloramphenicol) of these bioactive reagents substantially retarded the recovery and increased the death rate of such "dark" neurons. As concerns the dehydrating drugs and ion channel modulators, these effects are considered to be consequences of the fact that relatively large volumes (more than half of the original cell volume) of cytoplasmic fluid (water molecules, inorganic ions and metabolites) leave the affected cells through passive pores within a few minutes. The effects of the mitochondrial enzyme inhibitors appear to indicate that restoration of the original cell volume (recovery) demands metabolic (enzyme-mediated) energy. All these features support our previous assumption that the exogenous circumstances existing acutely after the formation of "dark" neurons in neurological diseases decide whether they will recover or die.

[Laparoscopic devascularization of the stomach and the abdominal esophagus with the LigaSure instrument in a porcine model]. / A gyomor és az abdominális nyelocsosza- kasz laparoszkópos devaszkularizációja LigaSure eszközzel sertés modellen.

OBJECTIVES: In this study we proved the feasibility of a new minimally invasive procedure for the devascularisation of the proximal stomach and the abdominal esophagus to prevent recurrent variceal bleeding in portal hypertension in a new animal model. MATERIALS AND METHODS: Experiments were performed on 12 female pigs, in two animal groups. In the first step (I. group n=6) portal hypertension was created by controlled laparoscopic clip ligation of the portal vein. The increased portal pressure was established by the needle puncture of the portal vein and the spleen. Two weeks later, the dilated veins were sealed along the lesser and greater curvature and the transhiatal esophagus with the 10 mm LigaSure instrument. Successful of the experimental model had encouraged us to perform this method on other animals (II. group, n=6), using the 5 mm instrument. RESULTS: There was no intraoperative bleeding after using both LigaSure instruments. Autopsy (2 weeks later) showed correct placed clips with partial occlusion of the portal vein without portal vein thrombosis. There was no evidence of postoperative bleeding. Histological investigation of the gastric surface confirmed complete sealing of the extended varices. CONCLUSION: The laparoscopic LigaSure instrument was found to be safe and suitable equipment for the ligation of the dilated veins along the gastric surface and the abdominal esophagus, and this method could be an alternate choice for the patients with recurrent variceal bleeding.