Sex-dependent effect of perinatal hypoxia on cardiac tolerance to oxygen deprivation in adults.

Epidemiological studies have demonstrated a relationship between the adverse influence of perinatal development and increased risk of ischemic heart disease in adults. From negative factors to which the fetus is subjected, the most important is hypoxia. The fetus may experience hypoxic stress under different conditions, including pregnancy at high altitude, pregnancy with anemia, placental insufficiency, and heart, lung, and kidney disease. One of the most common insults during the early stages of postnatal development is hypoxemia due to congenital cyanotic heart defects. Experimental studies have demonstrated a link between early hypoxia and increased risk of ischemia/reperfusion injury (I/R) in adults. Furthermore, it has been observed that late myocardial effects of chronic hypoxia, experienced in early life, may be sex-dependent. Unlike in males, perinatal hypoxia significantly increased cardiac tolerance to acute I/R injury in adult females, expressed as decreased infarct size and lower incidence of ischemic arrhythmias. It was suggested that early hypoxia may result in sex-dependent programming of specific genes in the offspring with the consequence of increased cardiac susceptibility to I/R injury in adult males. These results would have important clinical implications, since cardiac sensitivity to oxygen deprivation in adult patients may be significantly influenced by perinatal hypoxia in a sex-dependent manner.

Sex-Linked Differences in Cardiac Atrophy After Mechanical Unloading Induced by Heterotopic Heart Transplantation.

No information is available about sex-related differences in unloading-induced cardiac atrophy. We aimed to compare the course of unloading-induced cardiac atrophy in intact (without gonadectomy) male and female rats, and in animals after gonadectomy, to obtain insight into the influence of sex hormones on this process. Heterotopic heart transplantation (HT((x)) was used as a model for heart unloading. Cardiac atrophy was assessed as the weight ratio of heterotopically transplanted heart weight (HW) to the native HW on days 7 and 14 after HTx in intact male and female rats. In separate experimental groups, gonadectomy was performed in male and female recipient animals 28 days before HT(x) and the course of cardiac atrophy was again evaluated on days 7 and 14 after HT(x). In intact male rats, HT(x) resulted in significantly greater decreases in whole HW when compared to intact female rats. The dynamics of the left ventricle (LV) and right ventricle (RV) atrophy after HT(x) was quite similar to that of whole hearts. Gonadectomy did not have any significant effect on the decreases in whole HW, LV, and RV weights, with similar results in male and female rats. Our results show that the development of unloading-induced cardiac atrophy is substantially reduced in female rats when compared to male rats. Since gonadectomy did not alter the course of cardiac atrophy after HTx, similarly in both male and female rats, we conclude that sex-linked differences in the development of unloading-induced cardiac atrophy are not caused by the activity of sex hormones.

Influence of implant strategy on the transition from temporary left ventricular assist device to durable mechanical circulatory support.

OBJECTIVES: Bridging from a temporary microaxial left ventricular assist device (tLVAD) to a durable left ventricular assist device (dLVAD) is playing an increasing role in the treatment of terminally ill patients with heart failure. Scant data exist about the best implant strategy. The goal of this study was to analyse differences in the dLVAD implant technique and effects on patient outcomes. METHODS: Data from 341 patients (19 European centres) who underwent a bridge-to-bridge implant from tLVAD to dLVAD between January 2017 and October 2022 were retrospectively analysed. The outcomes of the different implant techniques with the patient on cardiopulmonary bypass, extracorporeal life support or tLVAD were compared. RESULTS: A durable LVAD implant was performed employing cardiopulmonary bypass in 70% of cases (n = 238, group 1), extracorporeal life support in 11% (n = 38, group 2) and tLVAD in 19% (n = 65, group 3). Baseline characteristics showed no significant differences in age (P = 0.140), body mass index (P = 0.388), creatinine level (P = 0.659), the Model for End-Stage Liver Disease (MELD) score (P = 0.190) and rate of dialysis (P = 0.110). Group 3 had significantly fewer patients with preoperatively invasive ventilation and cardiopulmonary resuscitation before the tLVAD was implanted (P = 0.009 and P < 0.001 respectively). Concomitant procedures were performed more often in groups 1 and 2 compared to group 3 (24%, 37% and 5%, respectively, P < 0.001). The 30-day mortality data showed significantly better survival after an inverse probability of treatment weighting in group 3, but the 1-year mortality showed no significant differences among the groups (P = 0.012 and 0.581, respectively). Postoperative complications like the rate of right ventricular assist device (RVAD) implants or re-thoracotomy due to bleeding, postoperative respiratory failure and renal replacement therapy showed no significant differences among the groups. Freedom from the first adverse event like stroke, driveline infection or pump thrombosis during follow-up was not significantly different among the groups. Postoperative blood transfusions within 24 h were significantly higher in groups 1 and 2 compared to surgery on tLVAD support (P < 0.001 and P = 0.003, respectively). CONCLUSIONS: In our analysis, the transition from tLVAD to dLVAD without further circulatory support did not show a difference in postoperative long-term survival, but a better 30-day survival was reported. The implant using only tLVAD showed a reduction in postoperative transfusion rates, without increasing the risk of postoperative stroke or pump thrombosis. In this small cohort study, our data support the hypothesis that a dLVAD implant on a tLVAD is a safe and feasible technique in selected patients.

[Abdominal complications in patients with implanted mechanical cardiac support]. / Abdominální komplikace u pacientu po implantaci mechanické srdecní podpory.

Patients with implanted mechanical cardiac support are exposed to the risk of various complications in the early postoperative period. Although thromboembolic and bleeding events occur most frequently in these patients, we cannot disregard other complications that can have a significant impact on the further development of the implanted patients condition. These include abdominal complications. Literature data show clearly that mortality in implanted patients who developed an abdominal complication is significantly higher than that in patients without postoperative abdominal complications.

[Outcomes of combined mitral valve repair surgery and aortic valve replacement in IKEM Praha]. / Výsledky kombinované plastiky mitrální a náhrady aortální chlopne v IKEM Praha.

AIM OF THE STUDY: We retrospectively analyzed long-term outcome of concomitant mitral valve repair and aortic valve replacement. METHODS: From 1996 to 2009 we performed mitral valve plasty with aortic valve replacement in 50 patients. Clinical and echocardiographic data were obtained from computer database and hospital records. Missing data were obtained through mailed questionnaire. We evaluated hospital mortality, long-term survival, thromboembolic and hemorrhagic complications and TR of 3+ on follow up echocardiography. RESULTS: Four patients who had previously undergone aortic valve surgery were excluded from the study. Aortic valve pathology was stenosis in 21 patients, regurgitation in 20 and 4 patients presented with mixed aortic disease. The etiology of mitral regurgitation was rheumatic in 6, non-rheumatic in 31 and infective in 6 patients. Aortic valve was replaced with mechanical prosthesis in 22 (mean age 59) and tissue prosthesis in 24 (mean age 71) patients. Additional surgical procedure was performed in 26 patients. Follow-up was 94% complete, with a mean duration of 51 months. Hospital mortality was 13%. Two and five year survival was 79% and 64% respectively. We noted one case of retroperitoneal hemorrhage and one stroke. We recorded 9 (19.6%) patients with residual TR of more than 3+ grade on follow up echocardiography. Out of 9 patients with residual TR, 3 were operated for rheumatic and 6 for non-rheumatic mitral valve disease. One patients underwent successful mitral valve replacement with mechanical prosthesis, 3 died and 5 are treated expectantly. CONCLUSION: We conclude that concomitant mitral valve repair with aortic valve replacement has high hospital mortality, excellent long-term survival and low complication rate. The durability of mitral valve repair in patients with rheumatic mitral valve disease is limited and replacement, rather that repair should be considered in this patient group.

[Technique of implantation and experience with temporary mechanical cardiac support in right ventricular failure]. / Technika implantace a zkusenosti s docasnou mechanickou srdecní podporou pri selhání pravé komory.

AIM: Severe right heart failure remains unfrequent but fatal complication of cardiac surgical procedures. Implantation of temporary right ventricular assist device may be life-saving procedure in various situations of right heart failure as: heart transplantation, LVAD therapy and post-cardiotomy failure. The aim of the study is an introduction of the implantation technique and retrospective review of current experience with the method. MATERIAL AND METHODS: Since January 2007 isolated right ventricular assist device Levitronix CentriMag has been implanted in 16 patients. Patients were divided into 3 groups: post transplantation (post-Tx), post LVAD implantation (post-LVAD) and other cardiac procedures (OCP). Success rate of weaning from RVAD, 30-days mortality and major complications has been assessed. OUTCOMES: Distribution of implants in groups was: post-Tx 5 pts (31%), post-LVAD 6 pts (38%) and 5 in OCP group (31%). The mean support time was 12 days. Off-pump implantation was achieved in 9 pts. The device was successfully weaned in 13 (81%) patients. 30-days mortality occurred in 1 case only. CONCLUSION: Presented outcomes are encouraging for broader acceptance of the therapy. Excellent success rate has been reached in post-Tx and post-LVAD. This study emphasises decesive role of proactive approach in early indication of RVAD implantation for achieving satisfactory results.

[Cardiosurgical procedures in patients refusing blood transfusions: IKEM outcomes]. / Kardiochirurgické operace u pacientu odmítajících krevní transfuze: výsledky v IKEM.

INTRODUCTION: Jehovah's Witnesses who require cardiac operation represent a specific challenge to the physicians. Members of this faith will not accept blood or blood products under any circumstances on the basis of religious grounds. Nevertheless cardiac operations belong to surgical interventions with potential severe bleeding and necessity of blood transfusions. THE AIM OF THE STUDY: The aim of this retrospective study was to analyze clinical data, operative and postoperative courses of patients operated at IKEM who refused blood transfusions. METHODS AND RESULTS: From January 1995 to August 2010, 73 Jehovah's Witnesses ranging in age from 19 to 82 years underwent cardiac surgery at our institute. Aortocoronary bypass were performed in 34 patients, valve surgery in 25 patients, 6 patients underwent concomitant aortocoronary bypass and valve surgery, 2 patients underwent aortocoronary bypass and resection of the left ventricle aneurysm and 2 patients underwent atrial septal defect repair and tricuspid valve anuloplasty. Ventricular septal sefect repair, atrial septal defect repair, Cor Cap device implantation and left ventricular epicardial electrodes implantation were performed in the other patients. Early 30-days mortality was 2.8 % (2 patients). CONCLUSION: We can conclude that cardiac surgery in Jehovah's Witnesses can be performed safety without blood transfusion and belongs to standard operating procedures at our institution.

[Vascular complications in transcatheter aortic valve implantation in IKEM]. / Cévní komplikace pri transkatetrové implantaci aortální chlopne v IKEM.

AIM: Retrograde transfemoral arterial approach is the most common technique of transcatheter aortic valve implantation. Diameter of available catheters is the limiting factor for percutaneous usage. We currently use 18 French third generation Medtronic Core Valve system. We retrospectively analyzed procedure related complications in our patient cohort. MATERIAL AND METHODS: Transcatheter aortic vale implantation with 18 French Medtronic Core Valve was performed in 35 patients (23 females, 12 males) in between 12/2008 and 7/2010. RESULTS: Mean age was 81.4 +/- 6.1 years (range 69-92), mean logistics EuroSCORE was 19.3 +/- 8.9% (range 8-42), mean aortic valve gradient 59.8 +/- 19.8 mm Hg (range 30-86 mm Hg (mean indexed aortic valve area 0.37 +/- 0.11 cm.

Effects of Acute Pump Speed Changes on Cerebral Hemodynamics in Patients With an Implantable Continuous-Flow Left Ventricular Assist Devices.

Mechanical circulatory support (MCS) with an implantable left ventricular assist device (LVAD) is an established therapeutic option for advanced heart failure. Most of the currently used LVADs generate a continuous stream of blood that decreases arterial pulse pressure. This study investigated whether a change of the pulse pressure during different pump speed settings would affect cerebral autoregulation and thereby affect cerebral blood flow (CBF). The study included 21 haemodynamically stable outpatients with a continuous-flow LVAD (HeartMate II, Abbott, USA) implanted a median of 6 months before the study (interquartile range 3 to 14 months). Arterial blood pressure (measured by finger plethysmography) was recorded simultaneously with CBF (measured by transcranial Doppler ultrasound) during baseline pump speed (8900 rpm [IQR 8800; 9200]) and during minimum and maximum tolerated pump speeds (8000 rpm [IQR 8000; 8200] and 9800 rpm [IQR 9800; 10 000]). An increase in LVAD pump speed by 800 rpm [IQR 800; 1000] from the baseline lead to a significant decrease in arterial pulse pressure and cerebral blood flow pulsatility (relative change ?24% and ?32%, both p < 0.01), but it did not affect mean arterial pressure and mean CBF velocity (relative change 1% and ?1.7%, p = 0.1 and 0.7). In stable patients with a continuous-flow LVAD, changes of pump speed settings within a clinically used range did not impair static cerebral autoregulation and cerebral blood flow.

Hepatocyte growth factor and antibodies to HLA and MICA antigens in heart transplant recipients.

Recent unconfirmed literature data suggest that elevated concentrations of the multifunctional cytokine hepatocyte growth factor (HGF) might be a marker of increased incidence of acute rejection after organ transplantation. The aim of this study was to test the hypothesis that HGF levels may correlate with the rejection and/or with the production of HLA and MHC Class I chain-related antigens A (MICA) specific antibodies. Sixty-three heart transplant recipients were included into the study. Hundred and eighty-five endomyocardial biopsies (EMB) obtained up to 6 months after transplantation were retrospectively analyzed for signs of cellular (CR) and antibody-mediated rejection (AMR). Pre- and post-transplant sera were tested for HGF concentrations and antibodies to HLA class I, class II and MICA antigens by xMap technology (Luminex). Pre-transplant HGF did not correlate with the incidence of CR or AMR. However, higher HGF concentrations correlated significantly with HLA antibody production before and after transplantation (P = 0.006 and P < 0.0001 respectively). Patients with both HLA class I and class II antibodies before transplantation had significantly lower AMR-free survival. Furthermore, recipients with pre-transplant donor-specific antibodies (DSA) had significantly lower AMR-free survival (50%) than recipients without pre-transplant HLA antibodies (90%) and patients with antibodies not specific to donor antigens (92%) (P = 0.005). Post-transplant MICA antibodies tended to be more frequent in patients with AMR (P = 0.063). In conclusion, elevated HGF concentrations in our study were not associated with the incidence of CR and/or AMR but with the presence of HLA-specific antibodies. Testing for DSA before heart transplantation by Luminex may be helpful for the identification of patients with increased risk of AMR.

Late effect of early hypoxic disturbance in the rat heart: gender differences.

Perinatal hypoxemia may have serious long-term effects on the adult cardiovascular system and may lead to sex-dependent changes in cardiac tolerance to acute ischemia in adult life. The aim of the study was to answer the question whether gonadectomy of the male and female rats in the early phase of ontogenetic development affects the late effect of perinatal hypoxia. Pregnant Wistar rats were placed into a normobaric hypoxic chamber (12 % O(2)) 7 days before the expected date of delivery. Newborn pups were kept in the chamber with their mothers for another 5 days after birth. After hypoxic exposure all animals were kept for 3 months in room air. Some of the pups were gonadectomized right after removal from the hypoxic chamber. Ventricular arrhythmias were assessed on isolated perfused hearts. Castration did not influence arrhythmogenesis in the adult normoxic or perinatally hypoxic female hearts. Nevertheless, the number of arrhythmias was decreased in perinatally hypoxic gonadectomized males. In conclusion, we have shown that perinatal normobaric hypoxia increased cardiac tolerance to acute ischemia in adult male rats; however, it had no late effect in females. Gonadectomy did not affect arrhythmogenesis in both normoxic and hypoxic female hearts, whereas in males significantly decreased the number of arrhythmias.

[Right ventricular dysfunction after left ventricular assist device implantation]. / Dysfunkce pravé komory po implantaci levostranné mechanické srdecní podpory.

OBJECTIVE: The frequency of long-term left ventricular assist device (LVAD) implantation is increasing. Acute right ventricular dysfunction or right ventricular failure after LVAD implantation has important influence on morbidity and mortality. The aim of our study was to assess the management of right ventricular dysfunction after LVAD implantation. METHODS: The study group comprised 21 patients with implanted HeartMate II LVAD since December, 2006 to April, 2009. We evaluated in retrospective fashion baseline parameters of cardiovascular and other organ systems before LVAD implantation, applied pharmacological and mechanical support for the right ventricle, and important clinical outcomes to the end ofJune, 2009. RESULTS: LVAD was implanted in 18 men and 3 women with mean age of 48.7 +/- 11.2 years. The most frequent diagnosis was dilatational cardiomyopathy (9 patients; 42.9%), and the most frequent indication for implantation was bridge-to-transplantation (19 patients; 90.4%). Pharmacological support of the right ventricle after LVAD implantation comprised dobutamine (21 patients; 100%), milrinone (21 patients; 100%), isoproterenol (1 patient; 4.8%), and levosimendan (5 patients; 23.8%). In 2 (9.5%) cases there was a need for repeated application of levosimendan during postoperative course. Inhalational nitric oxide was used in 14 (66.7%) patients. Despite extensive pharmacological support, 3 (14.3%) patients needed right ventricular assist device (RVAD) implantation. Most patients (9; 42.8%) survived to heart transplantation; in one (4.8%) case LVAD was successfuly explanted; 6 (28.6%) patients is living with LVAD; 5 (23.8%) patients died during LVAD support. CONCLUSION: After LVAD implantation there is a need for aggressive pharmacological, and in some cases mechanical, support of the right ventricular function to provide adequate blood flow to LVAD in order to minimize morbidity and mortality.

Increased Number of Mast Cells in Epicardial Adipose Tissue of Cardiac Surgery Patients With Coronary Artery Disease.

Chronic inflammation of adipose tissue is associated with the pathogenesis of cardiovascular diseases. Mast cells represent an important component of the innate defense system of the organism. In our work, we quantified mast cell number in epicardial adipose tissue (EAT), subcutaneous adipose tissue (SAT), and right atrial myocardium (RA) in patients undergoing open heart surgery (n=57). Bioptic samples of EAT (n=44), SAT (n=42) and RA (n=17) were fixed by 4 % paraformaldehyde and embedded into paraffin. An anti-mast cell tryptase antibody was used for immunohistochemical detection and quantification of mast cells. We also demonstrated immunohistochemically the expression of CD117 and chymase markers. In EAT of patients with coronary artery disease (CAD), higher incidence of mast cells has been found compared to patients without CAD (3.7±2.6 vs. 2.1±1.2 cells/mm(2)). In SAT and RA, there was no difference in the number of mast cells in CAD and non-CAD patients. Mast cells in SAT, EAT and RA expressed CD117 and chymase. An increased incidence of mast cells in EAT of CAD patients may indicate the specific role of these inflammatory cells in relation to EAT and coronary arteries affected by atherosclerosis.

Ontogenetic development of cardiac tolerance to oxygen deprivation - possible mechanisms.

Our present focus on the hypoxic immature heart is driven by clinical urgency: cyanotic congenital cardiac malformations remain the single largest cause of mortality from congenital defects and ischemic heart disease is no more the disease of the fifth and older decades but its origin as well as risk factors are present already during early ontogeny. Moreover, the number of adult patients operated for cyanotic congenital heart disease during infancy steadily increases. This group approaches the age of the rising risk of serious cardiovascular diseases, particularly ischemic heart disease. Experimental results have clearly shown that the immature heart is significantly more tolerant to oxygen deficiency than the adult myocardium. However, the mechanisms of this difference have not yet been satisfactorily clarified; they are likely the result of developmental changes in cardiac energy metabolism, including mitochondrial function. The high resistance of the newborn heart cannot be further increased by ischemic preconditioning or adaptation to chronic hypoxia; these protective mechanisms appear only with decreasing tolerance during development. Resistance of the adult myocardium to acute oxygen deprivation may be significantly influenced by perinatal hypoxia. These results suggest that the developmental approach offers new possibilities in the studies of pathogenesis, prevention and therapy of critical cardiovascular diseases.

[Transmyocardial laser revascularization]. / Transmyokardiální laserová revaskularizace.

AIM OF THE STUDY: The study looked at our results with transmyocardial laser revascularization. We also tried to ascertain the role of TMLR in current cardiothoracic surgical practice. METHODS: Twenty patients underwent TMLR at IKEM Praha in a period from 1999 to 2007. Patients were categorized into two separate groups. The first included patients who had TMLR as a single procedure. Second group comprised patients who underwent combined TMLR and direct bypass revascularization. Outcome measures were reduction of angina, improvements in exercise tolerance and left ventricular systolic function. RESULTS: Improvement in CCS classification of two and more classes has been achieved in almost half the patients who underwent TMLR combined with CABG, but only in 20% of patients after isolated TMLR. There was no change in left ventricular systolic function either in group of patients after TMLR or in group with hybrid procedure. There was also no change detected in myocardial perfusion in thallium scintigraphy studies. CONCLUSION: The study confirmed that TMLR has minimal perioperative complication rate and is safe. On the other hand our results failed to demonstrate any significant improvement in quality of life following TMLR. In our opinion TMLR should be reserved for symptomatic patients in CCS IV class when all other conventional treatment options have been exhausted.

[Management of deep device related infection in patient implanted with mechanical cardiac support device using V.A.C. system]. / Terapie závazných raných infekcí u pacientu se zavedenou mechanickou srdecní podporou pomocí V.A.C systému.

Infection remains the most significant cause of morbidity and mortality in pacients implanted with mechanical circulatory support devices (MCSD), reaching prevalence of 40-60% according various authors. Successful treatment of the whole spectrum of infectious complications is the basic determinant in archieving good results in MCSD patients. The treatment involves standard surgical procedures, as well as the use of vacuum assisted closure (V.A.C.) therapy in the last few years. We demonstrate successful management of deep device related infection using V.A.C therapy in a patient with MCSD, giving him the opportunity to heart transplantation, and thereafter successful treatment of poststernotomy mediastinitis in this imunosupressed pacient after heart transplantation.

Intraventricular placement of a spring expander does not attenuate cardiac atrophy of the healthy heart induced by unloading via heterotopic heart transplantation.

An important complication of the prolonged left ventricle assist device support in patients with heart failure is unloading-induced cardiac atrophy which proved resistant to various treatments. Heterotopic heart transplantation (HTx) is the usual experimental model to study this process. We showed previously that implantation of the newly designed intraventricular spring expander can attenuate the atrophy when examined after HTx in the failing heart (derived from animals with established heart failure). The present study aimed to examine if enhanced isovolumic loading achieved by implantation of the expander would attenuate cardiac post-HTx atrophy also in the healthy heart. Cardiac atrophy was assessed as the ratio of the transplanted-to-native heart weight (HW) and its degree was determined on days 7, 14, 21 and 28 after HTx. The transplantation resulted in 32±3, 46±2, 48±3 and 46±3 % HW loss when measured at the four time points; implantation of the expander had no significant effect on these decreases. We conclude that enhanced isovolumic loading achieved by intraventricular implantation of the expander does not attenuate the development of cardiac atrophy after HTx in the healthy heart. This indicates that such an approach does not represent a useful therapeutic measure to attenuate the development of unloading-induced cardiac atrophy.

Effect of acute and chronic simvastatin treatment on post-ischemic contractile dysfunction in isolated rat heart.

Statins are powerful lipid-lowering drugs, widely used in patients with hyperlipidemia and coronary artery disease. It was found, however, that statins appear to have a pleiotropic effect beyond their lipid-lowering ability. They exert anti-inflammatory, antithrombotic and antioxidant effects, increase nitric oxide production and improve endothelial dysfunction. The aim of our study was to examine the effect of chronic and acute treatment with simvastatin on the contractile function of the isolated perfused rat heart after ischemia/reperfusion injury. Contractile function was measured on isolated rat hearts, perfused according to Langendorff under constant pressure. The hearts were subjected to 20 min of global ischemia, followed by 40 min of reperfusion. To investigate the acute effect, simvastatin at a concentration of 10 micromol/l was added to the perfusion solution during reperfusion. In chronic experiments the rats were fed simvastatin at a concentration of 10 mg/kg for two weeks before the measurement of the contractile function. Acute simvastatin administration significantly increased reparation of the peak of pressure development [(+dP/dt)(max)] (52.9+/-8.2 %) after global ischemia, as compared with the control group (28.8+/-5.2 %). Similar differences were also observed in the time course of the recovery of [(+dP/dt)(max)]. Chronic simvastatin was without any protective effect. Our results reveal that the acute administration of simvastatin during reperfusion, unlike the chronic treatment, significantly reduced contractile dysfunction induced by ischemia/reperfusion injury. This supports the idea of possible cardioprotective effect of statin administration in the first-line therapy of the acute coronary syndrome.

Effects of increased myocardial tissue concentration of myristic, palmitic and palmitoleic acids on the course of cardiac atrophy of the failing heart unloaded by heterotopic transplantation.

The present experiments were performed to evaluate if increased heart tissue concentration of fatty acids, specifically myristic, palmitic and palmitoleic acids that are believed to promote physiological heart growth, can attenuate the progression of unloading-induced cardiac atrophy in rats with healthy and failing hearts. Heterotopic abdominal heart transplantation (HT(x)) was used as a model for heart unloading. Cardiac atrophy was assessed from the ratio of the native- to-transplanted heart weight (HW). The degree of cardiac atrophy after HT(x) was determined on days 7, 14, 21 and 28 after HT(x) in recipients of either healthy or failing hearts. HT(x) of healthy hearts resulted in 23+/-3, 46+/-3, 48+/-4 and 46+/-4 % HW loss at the four time-points. HT(x) of the failing heart resulted in even greater HW losses, of 46+/-4, 58+/-3, 66+/-2 and 68+/-4 %, respectively (P<0.05). Activation of "fetal gene cardiac program" (e.g. beta myosin heavy chain gene expression) and "genes reflecting cardiac remodeling" (e.g. atrial natriuretic peptide gene expression) after HT(x) was greater in failing than in healthy hearts (P<0.05 each time). Exposure to isocaloric high sugar diet caused significant increases in fatty acid concentrations in healthy and in failing hearts. However, these increases were not associated with any change in the course of cardiac atrophy, similarly in healthy and post-HT(x) failing hearts. We conclude that increasing heart tissue concentrations of the fatty acids allegedly involved in heart growth does not attenuate the unloading-induced cardiac atrophy.

Tolerance to acute ischemia in adult male and female spontaneously hypertensive rats.

Clinical and experimental studies have repeatedly indicated that overloaded hearts have a higher vulnerability to ischemia/reperfusion injury. The aim of the present study was to answer the question whether the degree of tolerance to oxygen deprivation in hearts of spontaneously hypertensive rats (SHR) may be sex-dependent. For this purpose, adult SHR and their normotensive control Wistar Kyoto (WKY) rats were used. The isolated hearts were perfused according to Langendorff at constant pressure (proportionally adjusted to the blood pressure in vivo). Recovery of contractile parameters (left ventricular systolic, diastolic and developed pressure as well as the peak rate of developed pressure) was measured during reperfusion after 20 min of global no-flow ischemia in 5 min intervals. Mean arterial blood pressure was measured by direct puncture of carotid artery under light ether anesthesia in a separate group of animals. The degree of hypertension was comparable in both sexes of SHR. The recovery of contractile functions in SHR males and females was significantly lower than in WKY rats during the whole investigated period. There was no sex difference in the recovery of WKY animals; on the other hand, the recovery was significantly better in SHR females than in SHR males. It may be concluded that the hearts of female SHR are more resistant to ischemia/reperfusion injury as compared with male SHR. This fact could have important clinical implications for the treatment of cardiovascular disease in women.