Blood pressure lowering effects of Lactobacillus helveticus fermented milk containing bioactive peptides Ile-Pro-Pro and Val-Pro-Pro; mechanistic, kinetic and clinical studies

The purpose of the present study was to evaluate the effects of Lactobacillus helveticus fermented milk (peptide milk) containing the casein-derived tripeptides Isoleucyl-prolyl-proline (Ile-Pro-Pro) and Valyl-prolyl-proline (Val-Pro-Pro) on blood pressure and vascular function in hypertensive subjects. The peptide milk lowered systolic and diastolic blood pressure in long-term use in hypertensive subjects when blood pressure was measured by using 24-hour ambulatory blood pressure measurement (ABPM). The blood pressure lowering effect was seen with the dose of 50 mg of tripeptides, and a tendency for lowering blood pressure was also observed when the dose was 5 mg. No adverse effects compared to the placebo group were reported or detected in laboratory analysis. The effect of the peptide milk on arterial stiffness was shown using two different methods, the ambulatory arterial stiffness index (AASI) and pulse wave analysis (PWA). According to the AASI, arterial stiffness was significantly reduced in the peptide milk group compared to the baseline level, but the difference was not significant compared to the placebo group. PWA showed that the peptide milk reduced arterial stiffness significantly compared to the placebo group. Endothelium-independent relaxation (nitroglycerin) and endothelium-dependent relaxation (salbutamol) did not differ between the groups. The blood pressure lowering mechanisms of the tripeptides and the kinetics of Ile-Pro-Pro were investigated using spontaneously hypertensive rats (SHR) and Sprague-Dawley rats. Previous studies have suggested that the blood pressure lowering effect of the tripeptides Ile-Pro-Pro and Val-Pro-Pro is based on angiotensin-converting enzyme inhibition, but the present findings did not agree with these previous studies. It was shown in SHR that calcium, potassium and magnesium may also have an important role in attenuating the development of hypertension as part of the peptide milk effect. In addition, the present study suggests indirectly that improved endothelial nitric oxide release capacity is not the mechanism by which peptide milk mediates its favourable circulatory effects. The kinetics of Ile-Pro-Pro were studied using adult Sprague-Dawley rats. The results showed that orally administered Ile-Pro-Pro is absorbed at least partly intact from the gastrointestinal tract. Radiolabelled Ile-Pro-Pro was distributed in different tissues and considerable radioactivity levels were found in tissues related to the renin-angiotensin system (RAS), adrenals, aorta and kidneys. Ile-Pro-Pro does not bind to plasma proteins, and therefore it is possible that its blood pressure lowering effect is mediated by free Ile-Pro-Pro. In conclusion, consumption of the peptide milk lowers blood pressure and reduces arterial stiffness in hypertensive subjects. Ile-Pro-Pro can be absorbed partly intact from the gastrointestinal tract and might accumulate in tissues related to the RAS. The precise blood pressure lowering mechanism of peptide milk remains to be studied.

Milk casein-derived tripeptides : A special focus on blood pressure and vascular function

Increased consumption of low-fat milk products is inversely associated with the risk of hypertension. The beneficial effect of milk on blood pressure is attributed to high calcium and potassium content but also to specific peptide sequences, which are cleaved from milk protein during gastrointestinal digestion, fermentation of milk with proteolytic starter cultures or enzymatic hydrolysis. Milk products fermented with Lactobacillus helveticus contain casein-derived tripeptides isoleucine-proline-proline (Ile-Pro-Pro) and valine-proline-proline (Val-Pro-Pro), which have been shown to possess antihypertensive effects in humans and in experimental animals. The aim of the present series of studies was to investigate the effects of tripeptides Ile-Pro-Pro and Val-Pro-Pro or fermented milk products containing them on vascular function and blood pressure and to elucidate the mechanisms behind them by using different experimental models of hypertension. Another aim was to characterize the acute effects of tripeptides on blood pressure and arterial stiffness in mildly hypertensive humans. Ile-Pro-Pro and Val-Pro-Pro or fermented milk products containing them attenuated the development of hypertension in two experimental models of hypertension, spontaneously hypertensive rat (SHR) and type 2 diabetic Goto-Kakizaki (GK) rat fed with high-salt diet. Significant differences in systolic blood pressure (SBP) were seen after 8 weeks treatment with tripeptide-containing products compared to control product. Plant sterols did not enhance this effect. Two differently produced tripeptide powders produced a similar attenuating effect on SBP in SHR. In mildly hypertensive subjects, a single administration of tripeptide- and plant sterol-containing fermented milk product decreased both SBP and diastolic blood pressure (DBP) over a period of 8 hours. Protective effect of tripeptides Ile-Pro-Pro and Val-Pro-Pro and fermented milk products containing them on vascular function was demonstrated in in vitro studies and long-term experimental studies. The effect was shown to be endothelium-dependent and possibly involving endothelium-derived hyperpolarizing factor (EDHF). In the clinical study, single administration of tripeptide-containing fermented milk product did not affect measures of arterial stiffness. Long-term treatment with fermented milk product containing Ile-Pro-Pro and Val-Pro-Pro inhibited angiotensin-converting enzyme (ACE) and decreased aldosterone levels thus showing beneficial effects on the renin-angiotensin system (RAS) in SHR and GK. No changes in the components of RAS were observed by the single administration of the same product in mildly hypertensive subjects. Increased levels of cGMP, NOx and citrulline suggest increased nitric oxide (NO) production by the tripeptides. Taken together, Ile-Pro-Pro and Val-Pro-Pro -containing products attenuate the development of hypertension after long-term treatment in experimental models of hypertension and possess an acute antihypertensive effect in mildly hypertensive subjects. In addition, these tripeptides show endothelium-mediated beneficial effects on vascular function. Attenuation of blood pressure increase by the tripeptides in experimental animals involves RAS, but its role in the antihypertensive effect in humans remains to be elucidated.

Early growth and adult health: focus on blood pressure, glucose tolerance status and body composition

Theory of developmental origins of adult health and disease proposes that experiences during critical periods of early development may have consequences on health throughout a lifespan. Thesis studies aimed to characterize associations between early growth and some components of the metabolic syndrome cluster. Participants belong to two epidemiological cohorts with data on birth measurements and, for the younger cohort, on serial recordings of weight and height during childhood. They were born as singletons between 1924-33 and 1934-44 in the Helsinki University Central Hospital, and 500 and 2003 of them, respectively, attended clinical studies at the age of 65-75 and 56-70 years, respectively. In the 65-75 year old men and women, the well-known inverse relationship between birth weight and systolic blood pressure (SBP) was confined to people who had established hypertension. Among them a 1-kg increase in birth weight was associated with a 6.4-mmHg (95% CI: 1.0 to 11.9) decrease in SBP. This relationship was further confined to people with the prevailing Pro12Pro polymorphism of the peroxisome proliferator-activated receptor-γ2 (PPARγ2) gene. People with low birth weight were more likely to receive angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers (ACEI/ARB, p=0.03), and, again, this relationship was confined to the carriers of the Pro12Pro (p=0.01 for interaction). These results suggest that the inverse association between birth weight and systolic BP becomes focused in hypertensive people because pathological features of BP regulation, associated with slow fetal growth, become self-perpetuating in adult life. Insulin resistance of the Pro12Pro carriers with low birth weight may interact with the renin-angiotensin system leading to raised BP levels. Habitual physical activity protected men and women who were small at birth, and thus at increased risk for the development of type 2 diabetes, against glucose intolerance more strongly. Among subjects with birth weight ≤3000 g, the odds ratio (OR) for glucose intolerance was 5.2 (95% CI: 2.1 to 13) in those who exercised less than 3 times per week compared to regular exercisers; in those who scored their exercise light compared with moderate exercisers (defined as comparable to brisk walking) the OR was 3.5 (1.5 to 8.2). In the 56-70 year old men a 1 kg increase in birth weight corresponded to a 4.1 kg (95% CI: 3.1 to 5.1) and in women to a 2.9 kg (2.1 to 3.6) increase in adult lean mass. Rapid gain in body mass index (BMI), i.e. crossing from an original BMI percentile to a higher one, before the age of 2 years increased adult lean mass index (LMI, lean mass/height squared) without excess fat accumulation whereas rapid gain in BMI during later childhood, despite the concurrent rise in LMI, resulted in a relatively higher increase in adult body fat mass. These findings illustrate how genes, the environment and their interactions, early growth patterns, and adult lifestyle modify adult health risks which originate from early life.

Technical efficiency of blood component preparation in blood centres of 10 European countries

Various reasons, such as ethical issues in maintaining blood resources, growing costs, and strict requirements for safe blood, have increased the pressure for efficient use of resources in blood banking. The competence of blood establishments can be characterized by their ability to predict the volume of blood collection to be able to provide cellular blood components in a timely manner as dictated by hospital demand. The stochastically varying clinical need for platelets (PLTs) sets a specific challenge for balancing supply with requests. Labour has been proven a primary cost-driver and should be managed efficiently. International comparisons of blood banking could recognize inefficiencies and allow reallocation of resources. Seventeen blood centres from 10 countries in continental Europe, Great Britain, and Scandinavia participated in this study. The centres were national institutes (5), parts of the local Red Cross organisation (5), or integrated into university hospitals (7). This study focused on the departments of blood component preparation of the centres. The data were obtained retrospectively by computerized questionnaires completed via Internet for the years 2000-2002. The data were used in four original articles (numbered I through IV) that form the basis of this thesis. Non-parametric data envelopment analysis (DEA, II-IV) was applied to evaluate and compare the relative efficiency of blood component preparation. Several models were created using different input and output combinations. The focus of comparisons was on the technical efficiency (II-III) and the labour efficiency (I, IV). An empirical cost model was tested to evaluate the cost efficiency (IV). Purchasing power parities (PPP, IV) were used to adjust the costs of the working hours and to make the costs comparable among countries. The total annual number of whole blood (WB) collections varied from 8,880 to 290,352 in the centres (I). Significant variation was also observed in the annual volume of produced red blood cells (RBCs) and PLTs. The annual number of PLTs produced by any method varied from 2,788 to 104,622 units. In 2002, 73% of all PLTs were produced by the buffy coat (BC) method, 23% by aphaeresis and 4% by the platelet-rich plasma (PRP) method. The annual discard rate of PLTs varied from 3.9% to 31%. The mean discard rate (13%) remained in the same range throughout the study period and demonstrated similar levels and variation in 2003-2004 according to a specific follow-up question (14%, range 3.8%-24%). The annual PLT discard rates were, to some extent, associated with production volumes. The mean RBC discard rate was 4.5% (range 0.2%-7.7%). Technical efficiency showed marked variation (median 60%, range 41%-100%) among the centres (II). Compared to the efficient departments, the inefficient departments used excess labour resources (and probably) production equipment to produce RBCs and PLTs. Technical efficiency tended to be higher when the (theoretical) proportion of lost WB collections (total RBC+PLT loss) from all collections was low (III). The labour efficiency varied remarkably, from 25% to 100% (median 47%) when working hours were the only input (IV). Using the estimated total costs as the input (cost efficiency) revealed an even greater variation (13%-100%) and overall lower efficiency level compared to labour only as the input. In cost efficiency only, the savings potential (observed inefficiency) was more than 50% in 10 departments, whereas labour and cost savings potentials were both more than 50% in six departments. The association between department size and efficiency (scale efficiency) could not be verified statistically in the small sample. In conclusion, international evaluation of the technical efficiency in component preparation departments revealed remarkable variation. A suboptimal combination of manpower and production output levels was the major cause of inefficiency, and the efficiency did not directly relate to production volume. Evaluation of the reasons for discarding components may offer a novel approach to study efficiency. DEA was proven applicable in analyses including various factors as inputs and outputs. This study suggests that analytical models can be developed to serve as indicators of technical efficiency and promote improvements in the management of limited resources. The work also demonstrates the importance of integrating efficiency analysis into international comparisons of blood banking.

Production of F4 Fimbrial Adhesin in Plants: a Model for Oral Porcine Vaccine against Enterotoxigenic Escherichia coli

F4 fimbriae of enterotoxigenic Escherichia coli (ETEC) are highly stable multimeric structures with a capacity to evoke mucosal immune responses. With these characters F4 offer a unique model system to study oral vaccination against ETEC-induced porcine postweaning diarrhea. Postweaning diarrhea is a major problem in piggeries worldwide and results in significant economic losses. No vaccine is currently available to protect weaned piglets against ETEC infections. Transgenic plants provide an economically feasible platform for large-scale production of vaccine antigens for animal health. In this study, the capacity of transgenic plants to produce FaeG protein, the major structural subunit and adhesin of F4 fimbria, was evaluated. Using the model plant tobacco, the optimal subcellular location for FaeG accumulation was examined. Targeting of FaeG into chloroplasts offered a superior accumulation level of 1% of total soluble proteins (TSP) over the other investigated subcellular locations, namely, the endoplasmic reticulum and the apoplast. Moreover, we determined whether the FaeG protein, when isolated from its fimbrial background and produced in a plant cell, would retain the key properties of an oral vaccine, i.e. stability in gastrointestinal conditions, binding to porcine intestinal F4 receptors (F4R), and inhibition of the F4-possessing (F4+) ETEC attachment to F4R. The chloroplast-derived FaeG protein did show resistance against low pH and proteolysis in the simulated gastrointestinal conditions and was able to bind to the F4R, subsequently inhibiting the F4+ ETEC binding in a dose-dependent manner. To investigate the oral immunogenicity of FaeG protein, the edible crop plant alfalfa was transformed with the chloroplast-targeting construct and equally to tobacco plants, a high-yield FaeG accumulation of 1% of TSP was obtained. A similar yield was also obtained in the seeds of barley, a valuable crop plant, when the FaeG-encoding gene was expressed under an endosperm-specific promoter and subcellularly targeted into the endoplasmic reticulum. Furthermore, desiccated alfalfa plants and barley grains were shown to have a capacity to store FaeG protein in a stable form for years. When the transgenic alfalfa plants were administred orally to weaned piglets, slight F4-specific systemic and mucosal immune responses were induced. Co-administration of the transgenic alfalfa and the mucosal adjuvant cholera toxin enhanced the F4-specific immune response; the duration and number of F4+ E. coli excretion following F4+ ETEC challenge were significantly reduced as compared with pigs that had received nontransgenic plant material. In conclusion, the results suggest that transgenic plants producing the FaeG subunit protein could be used for production and delivery of oral vaccines against porcine F4+ ETEC infections. The findings here thus present new approaches to develop the vaccination strategy against porcine postweaning diarrhea.

The TRAM flap for breast reconstruction : Studies on perioperative cutaneous blood flow, vasoconstriction, and indices of obesity

Breast reconstruction is performed for 10-15 % of women operated on for breast cancer. A popular method is the TRAM (transverse rectus abdominis musculocutaneous) flap formed of the patient’s own abdominal tissue, a part of one of the rectus abdominis muscles and a transverse skin-subcutis area over it. The flap can be raised as a pedicled or a free flap. The pedicled TRAM flap, based on its nondominant pedicle superior epigastric artery (SEA), is rotated to the chest so that blood flow through SEA continues. The free TRAM flap, based on its dominant pedicle deep inferior epigastric artery (DIEA), is detached from the abdomen, transferred to the chest, and DIEA and vein are anastomosed to vessels on the chest. Cutaneous necrosis is seen in 5–60 % of pedicled TRAM flaps and in 0–15 % of free TRAM flaps. This study was the first one to show with blood flow measurements that the cutaneous blood flow is more generous in free than in pedicled TRAM flaps. After this study the free TRAM flap has exceeded the pedicled flap in popularity as a breast reconstruction method, although the free flap it is technically a more demanding procedure than the pedicled TRAM flap. In pedicled flaps, a decrease in cutaneous blood flow was observed when DIEA was ligated. It seems that SEA cannot provide sufficient blood flow on the first postoperative days. The postoperative cutaneous blood flow in free TRAM flaps was more stable than in pedicled flaps. Development of cutaneous necrosis of pedicled TRAM flaps could be predicted based on intraoperative laser Doppler flowmetry (LDF) measurements. The LDF value on the contralateral skin of the flap decreased to 43 ± 7 % of the initial value after ligation of the DIEA in flaps developing cutaneous necrosis during the next week. Endothelin-1 (ET-1) is a powerful vasoconstrictory peptide secreted by vascular endothelial cells. A correlation was found between plasma ET-1 concentrations and peripheral vasoconstriction developing during and after breast reconstructions with a pedicled TRAM flap. ET-1 was not associated with the development of cutaneous necrosis. Felodipine, a vasodilating calcium channel antagonist, had no effect on plasma ET-1 concentrations, peripheral vasoconstriction or development of cutaneous necrosis in free TRAM flaps. Body mass index and thickness of abdominal were not associated with cutaneous necrosis in pedicled TRAM flaps.

Infections in lung and heart transplant recipients : Studies on the impact of bronchoscopy in the diagnosis of respiratory infections and detection of viral infections in blood and bronchoalveolar lavage fluid

Infection is a major cause of mortality and morbidity after thoracic organ transplantation. The aim of the present study was to evaluate the infectious complications after lung and heart transplantation, with a special emphasis on the usefulness of bronchoscopy and the demonstration of cytomegalovirus (CMV), human herpes virus (HHV)-6, and HHV-7. We reviewed all the consecutive bronchoscopies performed on heart transplant recipients (HTRs) from May 1988 to December 2001 (n = 44) and lung transplant recipients (LTRs) from February 1994 to November 2002 (n = 472). To compare different assays in the detection of CMV, a total of 21 thoracic organ transplant recipients were prospectively monitored by CMV pp65-antigenemia, DNAemia (PCR), and mRNAemia (NASBA) tests. The antigenemia test was the reference assay for therapeutic intervention. In addition to CMV antigenemia, 22 LTRs were monitored for HHV-6 and HHV-7 antigenemia. The diagnostic yield of the clinically indicated bronchoscopies was 41 % in the HTRs and 61 % in the LTRs. The utility of the bronchoscopy was highest from one to six months after transplantation. In contrast, the findings from the surveillance bronchoscopies performed on LTRs led to a change in the previous treatment in only 6 % of the cases. Pneumocystis carinii and CMV were the most commonly detected pathogens. Furthermore, 15 (65 %) of the P. carinii infections in the LTRs were detected during chemoprophylaxis. None of the complications of the bronchoscopies were fatal. Antigenemia, DNAemia, and mRNAemia were present in 98 %, 72 %, and 43 % of the CMV infections, respectively. The optimal DNAemia cut-off levels (sensitivity/specificity) were 400 (75.9/92.7 %), 850 (91.3/91.3 %), and 1250 (100/91.5 %) copies/ml for the antigenemia of 2, 5, and 10 pp65-positive leukocytes/50 000 leukocytes, respectively. The sensitivities of the NASBA were 25.9, 43.5, and 56.3 % in detecting the same cut-off levels. CMV DNAemia was detected in 93 % and mRNAemia in 61 % of the CMV antigenemias requiring antiviral therapy. HHV-6, HHV-7, and CMV antigenemia was detected in 20 (91 %), 11 (50 %), and 12 (55 %) of the 22 LTRs (median 16, 31, and 165 days), respectively. HHV-6 appeared in 15 (79 %), HHV-7 in seven (37 %), and CMV in one (7 %) of these patients during ganciclovir or valganciclovir prophylaxis. One case of pneumonitis and another of encephalitis were associated with HHV-6. In conclusion, bronchoscopy is a safe and useful diagnostic tool in LTRs and HTRs with a suspected respiratory infection, but the role of surveillance bronchoscopy in LTRs remains controversial. The PCR assay acts comparably with the antigenemia test in guiding the pre-emptive therapy against CMV when threshold levels of over 5 pp65-antigen positive leukocytes are used. In contrast, the low sensitivity of NASBA limits its usefulness. HHV-6 and HHV-7 activation is common after lung transplantation despite ganciclovir or valganciclovir prophylaxis, but clinical manifestations are infrequently linked to them.

Genistein and 17β-estradiol fatty acid esters in blood and adipose tissue and the structure-related antioxidant activity of estrogens on lipoproteins

Soy-derived phytoestrogen genistein and 17β-estradiol (E2), the principal endogenous estrogen in women, are also potent antioxidants protecting LDL and HDL lipoproteins against oxidation. This protection is enhanced by esterification with fatty acids, resulting in lipophilic molecules that accumulate in lipoproteins or fatty tissues. The aims were to investigate, whether genistein becomes esterified with fatty acids in human plasma accumulating in lipoproteins, and to develop a method for their quantitation; to study the antioxidant activity of different natural and synthetic estrogens in LDL and HDL; and to determine the E2 esters in visceral and subcutaneous fat in late pregnancy and in pre- and postmenopause. Human plasma was incubated with [3H]genistein and its esters were analyzed from lipoprotein fractions. Time-resolved fluoroimmunoassay (TR-FIA) was used to quantitate genistein esters in monkey plasma after subcutaneous and oral administration. The E2 esters in women s serum and adipose tissue were also quantitated using TR-FIA. The antioxidant activity of estrogen derivatives (n=43) on LDL and HDL was assessed by monitoring the copper induced formation of conjugated dienes. Human plasma was shown to produce lipoprotein-bound genistein fatty acid esters, providing a possible explanation for the previously reported increased oxidation resistance of LDL particles during intake of soybean phytoestrogens. Genistein esters were introduced into blood by subcutaneous administration. The antioxidant effect of estrogens on lipoproteins is highly structure-dependent. LDL and HDL were protected against oxidation by many unesterified, yet lipophilic derivatives. The strongest antioxidants had an unsubstituted A-ring phenolic hydroxyl group with one or two adjacent methoxy groups. E2 ester levels were high during late pregnancy. The median concentration of E2 esters in pregnancy serum was 0.42 nmol/l (n=13) and in pre- (n=8) and postmenopause (n=6) 0.07 and 0.06 nmol/l, respectively. In pregnancy visceral fat the concentration of E2 esters was 4.24 nmol/l and in pre- and postmenopause 0.82 and 0.74 nmol/l. The results from subcutaneous fat were similar. In serum and fat during pregnancy, E2 esters constituted about 0.5 and 10% of the free E2. In non-pregnant women most of the E2 in fat was esterified (the ester/free ratio 150 - 490%). In postmenopause, E2 levels in fat highly exceeded those in serum, the majority being esterified. The pathways for fatty acid esterification of steroid hormones are found in organisms ranging from invertebrates to vertebrates. The evolutionary preservation and relative abundance of E2 esters, especially in fat tissue, suggest a biological function, most likely in providing a readily available source of E2. The body s own estrogen reservoir could be used as a source of E2 by pharmacologically regulating the E2 esterification or hydrolysis.

Inhibition of Thrombin in Cardiac Surgery : experiments in a porcine model

Cardiac surgery involving cardiopulmonary bypass (CPB) induces activation of inflammation and coagulation systems and is associated with ischemia-reperfusion injury (I/R injury)in various organs including the myocardium, lungs, and intestine. I/R injury is manifested as organ dysfunction. Thrombin, the key enzyme of coagulation , plays a cenral role also in inflammation and contributes to regulation of apoptosis as well. The general aim of this thesis was to evaluate the potential of thrombin inhibition in reducing the adverse effects of I/R injury in myocardium, lungs, and intestine associated with the use of CPB and cardiac surgery. Forty five pigs were used for the studies. Two randomized blinded studies were performed. Animals underwent 75 min of normothermic CPB, 60 min of aortic clamping, and 120 min of reperfusion period. Twenty animals received iv. recombinant hirudin, a selective and effective inbitor of thrombin, or placebo. In a similar setting, twenty animals received an iv-bolus (250 IU/kg) of antithrombin (AT) or placebo. An additional group of 5 animals received 500 IU/kg in an open label setting to test dose response. Generation of thrombin (TAT), coagulation status (ACT), and hemodynamics were measured. Intramucosal pH and pCO2 were measured from the luminal surface of ileum using tonometry simultaneusly with arterial gas analysis. In addition, myocardial, lung, and intestinal biopsies were taken to quantitate leukocyte infiltration (MPO), for histological evaluation, and detection of apoptosis (TUNEL, caspase 3). In conclusion, our data suggest that r-hirudin may be an effective inhibitor of reperfusion induced thrombin generation in addition to being a direct inhibitor of preformed thrombin. Overall, the results suggest that inhibition of thrombin, beyond what is needed for efficient anticoagulation by heparin, has beneficial effects on myocardial I/R injury and hemodynamics during cardiac surgery and CPB. We showed that infusion of the thrombin inhibitor r-hirudin during reperfusion was associated with attenuated post ischemia left ventricular dysfunction and decreased systemic vascular resistance. Consequently microvascular flow was improved during ischemia-reperfusion injury. Improved recovery of myocardium during the post-ischemic reperfusion period was associated with significantly less cardiomyocyte apoptosis and with a trend in anti-inflammatory effects. Thus, inhibition of reperfusion induced thrombin may offer beneficial effects by mechanisms other than direct anticoagulant effects. AT, in doses with a significant anticoagulant effect, did not alleviate myocardial I/R injury in terms of myocardial recovery, histological inflammatory changes or post-ischemic troponin T release. Instead, AT attenuated reperfusion induced increase in pulmonary pressure after CPB. Taken the clinical significance of postoperative pulmonary hemodynamics in patients undergoing cardiopulmonary bypass, the potential positive regulatory role of AT and clinical implications needs to be studied further. Inflammatory response in the gut wall proved to be poorly associated with perturbed mucosal perfusion and the animals with the least neutrophil tissue sequestration and I/R related histological alterations tended to have the most progressive mucosal hypoperfusion. Thus, mechanisms of low-flow reperfusion injury during CPB can differ from the mechanisms seen in total ischemia reperfusion injury.