György Wéber

Expression and Protective Role of Heme Oxygenase-1 in Delayed Myocardial Preconditioning

Abstract:  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.

Burn trauma induces early HMGB1 release in patients: Its correlation with cytokines

High-mobility group box protein 1 (HMGB1) is a nuclear protein that may be released actively from monocytes and macrophages or passively from necrotic or damaged cells. Several experimental data suggest that burn injury is accompanied by elevated plasma HMGB, but there are only few data available about its changes in burned patients. The aim of this study was to follow the time course and the prognostic value of plasma HMGB1 and cytokine changes in patients with severe burn injury affecting more than 10% of body surface area (n = 26). Blood samples were taken on admission and on the following 5 days. Plasma HMGB1 concentration was measured by the enzyme-linked immunosorbent assay method, whereas IL-6, IL-8, and IL-10 were assayed by the cytometric bead array kit. The HMGB1 and IL-10 concentrations were elevated on admission and gradually decreased thereafter. Significant differences were observed between survivors and nonsurvivors in HMGB1 (P < 0.01) and IL-10 (P < 0.001) concentrations on admission with higher levels in nonsurvivors. IL-6 and IL-8 started to increase markedly from day 2. Positive correlation (r = 0.669, P < 0.01) was found between burned body surface and HMGB1 on admission. Receiver operating characteristic analysis of data on admission showed that at a level of 16 ng/mL, HMGB1 indicated lethality, with 75.0% sensitivity and 85.7% specificity. Using the cutoff level of 14 pg/mL, IL-10 predicted intensive care unit mortality, with 85.7% sensitivity and 84.2% specificity. Very early HMGB1 and IL-10 release may have an important impact on the immune function of patients after burn trauma.

Effect of N-acetylcysteine treatment on oxidative stress and inflammation after severe burn

Oxidative stress and inflammation generate edema in burns. The aim of our study was to assess effect of N-acetylcysteine (NAC) on oxidative stress, inflammation, fluid requirement, multiple organ dysfunction (MOD) score and vasoactive drug requirement. In this study 15 patients were on standard therapy, whereas for other 15 patients NAC was supplemented. Blood samples were taken on admission and on the next five consecutive mornings. Levels of malondialdehyde, protein sulfhydril (PSH) groups, reduced gluthation (GSH), activity of myeloperoxidase, catalase and superoxide dismutase enzymes and induced free radical generating capacity were measured as well as concentrations of TNF-α, IL-6, IL-8, and IL-10. MOD score, use of vasopressor agents and fluid utilisation were recorded daily. NAC treatment increased GSH level on days 4-5 (p<0.05) and PSH level on days 2-6 (p<0.05) compared to controls. Plasma IL-6 was lower on days 4-5 (p<0.05), IL-8 on days 4-6 (p<0.05) and IL-10 on days 4-6 (p<0.05) in NAC group. NAC group received less catecholamines than controls (p<0.01) from day 4 without significant differences in MOD score. NAC treatment is associated with a diminished oxidative stress reflected in preserved antioxidant levels, lower inflammation mirrored in lower interleukin levels and less vasopressor requirement.

Time course of pro- and anti-inflammatory cytokine levels in patients with burns—Prognostic value of interleukin-10

INTRODUCTION Trends and the prognostic value of cytokine responses to severe burns have not been fully examined in humans. Therefore, the aim of this study was to determine the time course and prognostic value of pro- and anti-inflammatory cytokines in the immediate post-burn period. PATIENTS AND METHODS Blood samples were taken for measuring IL-1 beta, IL-6, IL-8, IL-10, IL-12p70 and TNF-alpha concentrations from patients with more than 20% burned surface area on admission and on 5 consecutive days. Development of sepsis was assessed using standard criteria twice a day. RESULTS IL-12p70 remained under assay detection levels in the study period. IL-1 beta and TNF-alpha could be detected in stimulated blood samples with higher levels in survivors (n=21). IL-6 on days 4-5 and IL-8 on days 4-6 in non-stimulated plasma showed significant elevation in non-survivors (n=18) whereas in stimulated blood its levels did not differ significantly. IL-10 levels were significantly higher in non-survivors during the study period in non-stimulated, and except day 6 in stimulated blood. Using the cut-off level of 14 pg ml(-1) for IL-10 predicted ICU mortality with 85.4% sensitivity and 84.2% specificity on admission. CONCLUSION Early anti-inflammatory excess had a bad prognosis for patients suffering from severe burns.

Dynamic changes of matrix metalloproteinases and their tissue inhibitors in severe sepsis

PURPOSE Little is known about the dynamic changes of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) in sepsis. Our aim was therefore to investigate the time course of MMPs and their inhibitors in patients experiencing severe sepsis. METHODS Our prospective controlled analysis included 38 patients with severe sepsis. Plasma levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured daily at a 5-day-long period with enzyme-linked immunosorbent assay. Seventeen healthy volunteers were invited as controls. RESULTS MMP-2 showed no difference compared to controls, whereas significantly elevated MMP-9 levels were detected on admission (P < .005). Significantly elevated but declining TIMP-1 levels were measured during the whole trial (P < .002-.004). Except for the second day, TIMP-2 levels were significantly lower than controls (P < .05-.009). MMP2/TIMP-1 ratios were significantly lower in septic patients (P < .03-.006), whereas MMP-2/TIMP-2 ratios were elevated throughout our study (P < .03-.006). MMP-9/TIMP-1 ratios were significantly lower at the first 3 days (P < .05-.008). MMP-9/TIMP-2 was significantly elevated on admission (P < .006). CONCLUSIONS Our research is the first follow-up study dealing with MMPs, TIMPs, and their ratios in severe sepsis. Our results indicate that MMPs and TIMPs may play a crucial role in severe sepsis, especially TIMP-1, MMP-9, and possibly TIMP-2, after an extensive study.

Minimally invasive surgical technologies: Challenges in education and training

The laparoscopic revolution has fundamentally changed surgical technology. However, this new technology, with its unique psychomotor adaptations, has been a challenge for both experienced and novice surgeons. This review summarizes the history of practical education and training methods and those currently used to ensure surgeons safely practice these new surgical skills.

Cardioprotective action of urocortin in early pre- and postconditioning

Abstract:  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.

Effect of N-acetylcysteine treatment on the expression of leukocyte surface markers after burn injury☆

Oxidative stress and inflammatory processes generate edema in burns. Treatment of consequent hypovolemia is a challenge. The aim of study was to assess if glutathione pro-drug N-acetylcysteine (NAC) can influence inflammation and fluid requirement. We also aimed to compare organ functions scores and vasoactive drug requirement. This prospective randomised study involved 28 patients with burn injury affecting more than 20% of body surface area. Fourteen patients were on standard therapy, whereas for other 14 patients NAC was supplemented. Blood samples were taken on admission and on the next five consecutive mornings. Leukocyte surface marker expressions were determined, multiple organ function scores, use of vasopressor agents and fluid requirements were recorded daily. Expression of CD11a (p < 0.05), CD18 (p < 0.05) and CD97 (p < 0.01) on the granulocytes were significantly lower in the NAC treated group, similarly to lymphocyte CD 49d (p < 0.05) and monocyte CD 49d (p < 0.01) and CD 97 (p < 0.05) expression. No significant difference was found in the fluid requirement between groups but patients the NAC group required less vasopressor and inotropic drugs from day 4. NAC treatment is associated with a less pronounced inflammation reflected in lower CD marker expression and vasopressor requirement.

Examination of Protective Effect of Ischemic Postconditioning After Small Bowel Autotransplantation

Ischemia/reperfusion (I/R) injury is a serious condition that results from some surgical procedures, including intestinal transplantation. Ischemic postconditioning is defined as brief periods of reperfusion alternating with reocclusion applied during the early minutes after reperfusion. The objective of this study was to investigate the effect of ischemic postconditioning before small bowel autotransplantation. Total orthotopic intestinal autotransplantation was performed in 30 white domestic pigs. Grafts were stored in cold University of Wisconsin solution for 1, 3, or 6 hours. Duration of reperfusion was 3 hours in all grafts. Before reperfusion, the intestine was postconditioned via 3 cycles of ischemia for 30 seconds and reperfusion for 30 seconds (ischemic postconditioning protocol). Tissue from the small intestine was obtained after laparotomy (control group) and at the end of reperfusion periods. To monitor oxidative stress, tissue concentrations of malondialdehyde and reduced glutathione, and activity of superoxide dismutase were determined at spectrophotometry. Tissue damage on sections stained with hematoxylin- eosin was evaluated using a quantitative method (Scion Image software; Scion Corp, Frederick, Maryland). Our results demonstrated that ischemic postconditioning significantly decreased the reperfusion-ended lipid peroxidation value (mean +/- SEM, 142.0 +/- 7.1 micromol/g vs 125.0 +/- 2.1 micromol/g; P < .05). Moreover, the capacity and activity of endogenous antioxidant protective systems (glutathione 789+/-8.0 micromol/g vs 934 +/- 5.7 micromol/g, and superoxide dismutase 110 +/- 9 IU/g vs 126 +/- 4 IU/g; P < .05) remained higher in the ischemic postconditioning groups compared with tissues without ischemic postconditioning. At quantitative analysis, tissue injury was increased by the duration of cold preservation. The greatest injury was observed in the mucosal and submucosal layers and in the depth of crypts after 6 hours of preservation. Ischemic postconditioning significantly decreased intestinal wall injury in each group (P < .05). It was concluded that ischemic postconditioning before reperfusion mitigated oxidative stress and histologic damage during small bowel autotransplantation.

Efficacy of different hemostatic devices for severe liver bleeding: a randomized controlled animal study.

Background. Correct hemostasis in liver surgery is hard to achieve because of the oozing bleeding. The aim of this study was to compare the potential benefits of a new compress to the 2 commercial hemostatic compresses. Methods. Collagen- and cellulose-based hemostatics were investigated. A standardized resection was treated by applying different hemostatics in a randomized order, and bleeding times were measured. Macroscopic evaluation of the liver and tissue sampling for histological investigations were carried out after 21 days. Results . The bleeding times of bovine collagen (BoCo), protein-coated equine collagen (PECo), and oxidized cellulose (OxCe) were 140 ± 88, 243 ± 140 (P = .005 vs BoCo), and 352 ± 70 s (P < .001 vs BoCo), respectively. Microscopic evaluation of the PECo presented fibrosis and significant inflammation in the implantation zone, whereas BoCo and OxCe caused only fibrosis in the wound area. Conclusion. BoCo showed significantly better hemostatic effect than PECo and OxCe.