Evaluation of Nitrosative/Oxidative Stress and Inflammation in Heart Failure with Preserved and Reduced Ejection Fraction

Heart failure (HF) is a complex syndrome characterized by impaired cardiac function. Two common subtypes of HF include heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). In this study, we aimed to evaluate and compare the plasma levels of 3-nitrotyrosine (3-NT)-as a marker of nitrosative/oxidative stress and myeloperoxidase (MPO)-as an indicator of inflammation between HFpEF and HFrEF. Twenty-seven patients diagnosed with HFpEF and twenty-two with HFrEF were enrolled in this study. Additionally, forty-one patients were recruited for the control group. An echocardiographic assessment was conducted, followed by the collection of blood samples from all participants. Subsequently, the levels of 3-NT and MPO were quantified using the ELISA method. Comprehensive clinical characteristics and medical histories were obtained. Circulating levels of 3-NT were significantly higher in the HFpEF patients than in the control and the HFrEF groups. Nitrosative/oxidative stress is significantly intensified in HFpEF but not in HFrEF.

Inflammatory Forms of Cardiomyocyte Cell Death in the Rat Model of Isoprenaline-Induced Takotsubo Syndrome

Takotsubo syndrome (TTS) is associated with inflammatory response, therefore the aim of the study was to evaluate the presence and dynamics of inflammatory-associated forms of cell death, necroptosis, and pyroptosis in the female rat model of isoprenaline (ISO)-induced TTS. TTS was induced in female Sprague Dawley rats (n = 36) by ISO 150 mg/kg intraperitoneally. Animals were divided into four groups: TTSO (TTS+ovariectomy; n = 10), TTSP (TTS+sham operation; n = 10), CO (0.9% NaCl+ovariectomy; n = 8), CP (0.9% NaCl+sham operation; n = 8). Histopathological analysis, evaluation of plasma concentration, and myocardial expression of pyroptosis- and necroptosis-associated proteins were performed. TTSO and TTSP groups had higher plasma concentrations of interleukin-1β in comparison with the controls. Low myocardial protein expression of mixed lineage kinase domain-like pseudokinase (MLKL), caspase-1 (Casp-1), and calcium/calmodulin-dependent kinase type II isoform delta (CAMKIIδ) was visible 6 and/or 12 h post-ISO. Twenty-four hours post-ISO, high myocardial and vascular protein expression of CAMKIIδ was visible in TTSO but not TTSP rats, while high myocardial expression of MLKL and Casp-1 was visible both in TTSO and TTSP rats. The course of TTS is associated with activation of inflammatory-associated programmed cell death, necroptosis, and pyroptosis, therefore inflammation may be a primary response occurring simultaneously with cardiomyocyte death in TTS.

Are medical students interested in research? - students' attitudes towards research

BACKGROUND

Throughout the years significant progress has been observed in all medical fields. It was possible to achieve thanks to a wide range of scientists, including physician-scientists. However, in recent years their number is significantly declining. Thus we have aimed to explore the attitudes of medical students towards research.

METHODS

The cross-sectional study was conducted among medical students of Medical University of Warsaw between the 1st and 23rd of December 2019. Survey examining scientific interests and activities, opinions on selected research issues, and perception of potential barriers to research activities has been distributed to 838 students and collected from 695 (391 students of the 2nd year and 304 of the 5th year) with a response rate of 82.9%. Descriptive statistics, the Chi-squared test, U-Mann-Whitney, and Kruskal-Wallis tests were used for between-group comparisons. The differences were considered statistically significant if the p values were <.05.

RESULTS

55.2% of responders rated their scientific interests in high school as high, with no significant differences between 2nd and 5th-year students. 33.8% (n = 233) of all students plan to pursue research activity after graduation, and 52.8% (n = 360) plan to obtain PhD title. Students who presented higher scientific interests in high school more often were involved in research projects at the university (24.7% vs 17.5%, p = .044), and showed higher interest in pursuing a research career (37.9% vs 28.9%, p = .02). Lack of time and knowledge on starting a research project were perceived as the main barriers to scientific work.

CONCLUSIONS

Many medical students express research interests, are involved in scientific projects, and plan to pursue their careers in this direction. There is a majority of students with lower attitudes towards research. Medical universities should consider adapting their curricula accordingly to accommodate the needs of both groups and respond to the shortage of physicians working in clinics and research.KEY MESSAGESOne-third of medical students plan to pursue career in medical research after graduation.Students who presented higher scientific interests in the high school are more often involved in research projects at the university and show higher interest in pursuing a research career.According to medical students, lack of time, resources and funding and insufficient knowledge how to start a research project are the most important barriers to research activity.

Biochemical and clinical evaluation of endothelial injury after distal or traditional transradial access in percutaneous interventions

BACKGROUND

Distal transradial access (dTRA) has been proposed as an alternative to traditional transradial access (TRA) in cardiac catheterization.

AIMS

The study aimed to compare these two transradial approaches: TRA and dTRA in terms of clinical and biochemical aspects.

METHODS

Two hundred patients who qualified for the elective coronary procedure were included. The patients were assigned to one of the groups depending on their vascular access. The groups were compared in terms of perceived pain using the Visual Analogue Scale (VAS), time of gaining access, need for conversion, and local complications. Additionally, in forty patients circulating endothelial injury markers: endothelin 1 (ET-1), interleukin 8 (IL-8), and soluble vascular cell adhesion molecule-1 (sVCAM-1) were assessed.

RESULTS

Successful cannulation was obtained in 84 (100%) in the TRA group and in 98 (84%) subjects in the dTRA (P <0.001). dTRA was associated with higher level of pain perceived at the time of gaining vascular approach than TRA; median VAS score (interquartile range [IQR]): 4 (2-5) vs. 2 (2-4) (P = 0.04). The mean time (standard deviation [SD]) needed to cannulate the artery in dTRA was longer than in TRA: 81 (8) seconds vs. 50 (4) seconds (P = 0.04). ET-1 concentration was (SD) 2.08 (0.19) pg/ml [dTRA] vs. 2.00 (0.29) [TRA] pg/ml (P = 0.83); sVCAM-1: 12.71 (3.97) ng/ml vs. 12.86 (4.29) ng/ml (P = 0.98); IL-8: 8.81 (0.42) ng/ml vs. 9.15 (0.52) ng/ml (P = 0.62). Th number of complications after procedures did not differ between these two approaches.

CONCLUSIONS

Cannulation of dTRA is associated with a lower success rate and higher pain perceived. dTRA is not inferior to TRA when safety issues and vascular injury are considered.

MEDICATION ADHERENCE AND ITS IMPACT ON THE AVERAGE LIFE EXPECTANCY AFTER ST-SEGMENT ELEVATION MYOCARDIAL INFARCTION: THE RESULTS OF THE UKRAINIAN STIMUL REGISTRY

OBJECTIVE

The aim: The present study aimed to evaluate the adherence to medications prior and within a two-year period after ST-segment elevation myocardial infarction (STEMI) and to estimate its impact on the average lifespan of patients after STEMI.

PATIENTS AND METHODS

Materials and methods: 1,103 patients with STEMI were enrolled in the prospective Ukrainian STIMUL registry with 24-month follow-up. The relationship between adherence to medical treatment and average lifespan was evaluated.

RESULTS

Results: The majority of prior STEMI patients were characterized with high and very high cardiovascular risk. The rate of revascularization was 29.9% (21.5% pPCI, 8.4% fibrinolytic therapy). The main reason for the low level of pPCI was late hospitalization and the inaccessibility of pPCI. This contributed greatly to in-hospital mortality (11.3%). Adherence to all medications progressively decreased (p < 0.001) within 24 months after STEMI. Permanent use of acetylsalicylic acid (ASA) and statins during the two-year follow-up was associated with 7.0% of the mortalities, whereas non-adherence to medications was related to a 15% risk of death (OR 4.2; 95% CI 0.2-0.9; p < 0.05). The average life expectancy with regular use of ASA and statins within 24 months after STEMI was 62.3 ± 1.1 years (95% CI 60.1-64.4; p < 0.05) and 61.2 ± 0.9 years with non-regular use of ASA and statins (95% CI 59.4-62.9; p < 0.05).

CONCLUSION

Conclusions: Adherence to evidence-based medicines was low in the STIMUL population both prior and after STEMI. This worsened cardiovascular prognosis and reduced average lifespan by one year within the following two years after STEMI.

Evaluation and Comparison of the STIMUL Extended and Simplified Risk Scores for Predicting Two-Year Death in Patients Following ST-Segment Elevation Myocardial Infarction

Background and Objectives: The management of ST-segment elevation myocardial infarction (STEMI) requires a patient’s long-term risk to be estimated. The objective of this study was to develop extended and simplified models of two-year death risk estimation following STEMI that include and exclude cardiac troponins as prognostic factors and to compare their performance with each other. Materials and Methods: Extended and simplified multivariable logistic regression models were elaborated using 1103 patients with STEMI enrolled and followed up in the STIMUL (ST-segment elevation Myocardial Infarctions in Ukraine and their Lethality) registry. Results: The extended STIMUL risk score includes seven independent risk factors: age; Killip class ≥ II at admission; resuscitated cardiac arrest; non-reperfused infarct-related artery; troponin I ≥ 150.0 ng/L; diabetes mellitus; and history of congestive heart failure. The exclusion of cardiac troponin in the simplified model did not influence the predictive value of each factor. Both models divide patients into low, moderate, and high risk groups with a C-statistic of 0.89 (95% CI 0.84–0.93; p < 0.001) for the extended STIMUL model and a C-statistic of 0.86 (95% CI 0.83–0.99; p < 0.001) for the simplified model. However, the addition of the level of troponin I to the model increased its prognostic value by 10.7%. Conclusions: The STIMUL extended and simplified risk estimation models perform well in the prediction of two-year death risk following STEMI. The simplified version may be useful when clinicians do not know the value of cardiac troponins among the population of STEMI patients.

Interaction of Orexin A and Vasopressin in the Brain Plays a Role in Blood Pressure Regulation in WKY and SHR Rats

Background

Orexin A (OXA) and vasopressin (AVP) exert a central hypertensive effect due to an increase in sympathetic nerve activity. To date, little is known about the interaction of these 2 neuropeptides in the central regulation of blood pressure. The present study compared the consequences of infusion into the left cerebral ventricle (ICV) of OXA on mean arterial blood pressure (MABP) in normotensive (WKY) and spontaneously hypertensive (SHR) rats, and explored whether the central pressor action of OXA in these 2 strains depends on activation of brain AVP V1a receptors (V1aR).

Material/Methods

Ten groups of experiments were performed on 12-week-old WKY and SHR rats implanted with ICV cannulas for infusion of OXA (3 nmol) and V1aR antagonist (V1aRANT, 500 ng), administered separately and together. Levels of V1aR and OXR in the medulla oblongata of WKY and SHR rats were compared in separate series.

Results

We found that: 1) OXA significantly increased MABP only in WKY rats, 2) V1aRANT prevented an increase in MABP induced by OXA in WKY rats and decreased MABP in SHR rats, 3) OXA abolished the hypotensive action of V1aRANT in SHR rats, and 4) SHR rats had significantly higher levels of OX1R and V1aR proteins and OX1R mRNA in the brain medulla.

Conclusions

The present study shows that OXA and AVP can interact in the brain to affect blood pressure regulation, and that this interaction differs in normotension and hypertension.

Central interaction between the apelinergic and vasopressinergic systems in the regulation of the haemodynamic parameters in rats maintained on a high-fat diet

A high-fat diet can affect the central activity of the apelinergic and vasopressinergic systems, which can have a significant impact on cardiovascular regulation. The aim of the study was to investigate the role of the central interaction between apelin and vasopressin in the regulation of the cardiovascular system in Sprague Dawley rats maintained on a normal-fat diet (NFD) or on a high-fat diet (HFD). The animals were instrumented with a cannula implanted into the left cerebral ventricle for intracerebroventricular (ICV) infusions of saline (0.9% NaCl), apelin-13 (APLN-13), V1a receptor antagonist (V1aRANT) APJ receptor antagonist (F13A), vasopressin (AVP); and with a catheter placed within the femoral artery for mean arterial blood pressure and heart rate monitoring. Blood, the hypothalamus and the medulla oblongata were collected for biochemical analysis. The hypertensive effect of APLN-13 was blocked by a prior ICV infusion of V1aRANT, only in the NFD rats. However, the hypertensive effect of AVP was blocked by the prior ICV infusion of F13A in both the NFD and HFD rats. A HFD caused an increase in the protein level of APJ and V1a receptors, both in the hypothalamus and the medulla oblongata. This study confirms the presence of an interaction between both peptides in the central regulation of the cardiovascular system in rats on a NFD or a HFD.

Impaired hypotensive effects of centrally acting oxytocin in SHR and WKY rats exposed to chronic mild stress

The present study was designed to determine the role of centrally acting oxytocin (OT) in the regulation of blood pressure during chronic mild stress (CMS) in spontaneously hypertensive (SHR; n = 36) and normotensive Wistar-Kyoto (WKY; n = 38) rats. The rats were implanted with osmotic minipumps for intracerebroventricular infusions of 0.9% NaCl, OT, and oxytocin receptor antagonist (OTANT) and divided into two groups: SHR and WKY 1) exposed to 4-wk CMS and 2) not exposed to stress (controls). After 4 wk, hemodynamic parameters were recorded at rest and after an application of acute stressor [air-jet stress (AJS)]. Resting mean arterial blood pressure (MAP) was significantly lower in CMS-exposed SHR and WKY infused with OT than in the corresponding groups receiving saline. Exposure to CMS exaggerated the AJS-dependent pressor response in WKY receiving saline but not in the corresponding group of SHR. OT infusion reduced the AJS-dependent pressor response in both CMS-exposed and not exposed SHR and in CMS-exposed WKY. Intracerebroventricular infusion of OTANT potentiated the AJS-dependent pressor response in both stressed and not stressed WKY rats but not in SHR. The results show that centrally delivered OT decreases resting MAP during CMS in both SHR and WKY rats and that in SHR it reduces pressor responses to AJS under control and CMS conditions, whereas in WKY this effect is significant only after CMS exposure. The study indicates that endogenous centrally acting OT may play an essential role in buffering pressor responses to AJS in CMS-exposed and not exposed WKY rats and that this function is significantly impaired in SHR.

The influence of post-infarct heart failure and high fat diet on the expression of apelin APJ and vasopressin V1a and V1b receptors

Vasopressin and apelin are reciprocally regulated hormones which are implicated in the pathophysiology of heart failure and the regulation of metabolism; however, little is known about their interactions under pathological conditions. In this study, we determined how post-infarct heart failure (HF) and a high fat diet (HFD) affect expression of the apelin APJ receptor (APJR) and the V1a (V1aR) and V1b (V1bR) vasopressin receptors in the hypothalamus, the heart, and the retroperitoneal adipose tissue. We performed experiments in male 4-week-old Sprague Dawley rats. The animals received either a normal fat diet (NFD) or a HFD for 8 weeks, then they underwent left coronary artery ligation to induce HF or sham surgery (SO), followed by 4 weeks of NFD or HFD. The HF rats showed higher plasma concentration of NT-proBNP and copeptin. The HF reduced the APJR mRNA expression in the hypothalamus. The APJR and V1aR protein levels in the hypothalamus were regulated both by HF and HFD, while the V1bR protein level in the hypothalamus was mainly influenced by HF. APJR mRNA expression in the heart was significantly higher in rats on HFD, and HFD affected the reduction of the APJR protein level in the right ventricle. The regulation of APJR, V1aR and V1bR expression in the heart and the retroperitoneal adipose tissue were affected by both HF and HFD. Our study demonstrates that HF and HFD cause significant changes in the expression of APJR, V1aR and V1bR, which may have an important influence on the cardiovascular system and metabolism.

High-fat diet and chronic stress reduce central pressor and tachycardic effects of apelin in Sprague-Dawley rats

Central application of apelin elevates blood pressure and influences neuroendocrine responses to stress and food consumption. However, it is not known whether the central cardiovascular effects of apelin depend also on caloric intake or chronic stress. The purpose of the present study was to determine the effects of intracerebroventricular administration of apelin on blood pressure (mean arterial blood pressure) and heart rate in conscious Sprague-Dawley rats consuming either a normal-fat diet (NFD) or high-fat diet (HFD) for 12 weeks. During the last 4 weeks of the food regime, the rats were exposed (NFDS and HFDS groups) or not exposed (NFDNS and HFDNS groups) to chronic stress. Each group was divided into two subgroups receiving intracerebroventricular infusions of either vehicle or apelin. Apelin elicited significant increase of mean arterial blood pressure and heart rate in the NFDNS rats. This effect was abolished in the HFDNS, HFDS and NFDS groups. HFD resulted in a significant elevation of blood concentrations of total cholesterol, triglycerides glucose and insulin. Chronic stress reduced plasma concentration of total and high-density lipoprotein cholesterol, and increased plasma corticosterone concentration and APJ receptor mRNA expression in the hypothalamus, whereas a combination of a HFD with chronic stress resulted in the elevation of plasma triglycerides, total cholesterol and low-density lipoprotein cholesterol, and in increased plasma corticosterone concentration, apelin concentration and APJ receptor mRNA expression in the hypothalamus. It is concluded that a HFD and chronic stress result in significant suppression of the central pressor action of apelin, and cause significant though not unidirectional changes of metabolic and endocrine parameters.

Oxytocin differently regulates pressor responses to stress in WKY and SHR rats: the role of central oxytocin and V1a receptors

The role of central oxytocin in the regulation of cardiovascular parameters under resting conditions and during acute stress was investigated in male normotensive Wistar-Kyoto (WKY; n = 40) and spontaneously hypertensive rats (SHR; n = 28). In Experiment 1, mean arterial blood pressure (MABP) and heart rate (HR) were recorded in WKY and SHR rats at rest and after an air-jet stressor during intracerebroventricular (ICV) infusions of vehicle, oxytocin or oxytocin receptor (OTR) antagonist. In Experiment 2, the effects of vehicle, oxytocin and OTR antagonist were determined in WKY rats after prior administration of a V1a vasopressin receptor (V1aR) antagonist. Resting MABP and HR were not affected by any of the ICV infusions either in WKY or in SHR rats. In control experiments (vehicle), the pressor response to stress was significantly higher in SHR. Oxytocin enhanced the pressor response to stress in the WKY rats but reduced it in SHR. During V1aR blockade, oxytocin infusion entirely abolished the pressor response to stress in WKY rats. Combined blockade of V1aR and OTR elicited a significantly greater MABP response to stress than infusion of V1a antagonist and vehicle. This study reveals significant differences in the regulation of blood pressure in WKY and SHR rats during alarming stress. Specifically, the augmentation of the pressor response to stress by exogenous oxytocin in WKY rats is caused by its interaction with V1aR, and endogenous oxytocin regulates the magnitude of the pressor response to stress in WKY rats by simultaneous interaction with OTR and V1aR.

Individuals with high-normal blood pressure have different metabolic and haemodynamic characteristics to those with optimal blood pressure

BACKGROUND

The ESH classification of blood pressure includes the high-normal blood pressure (HNBP) category, which is within normal limits but associated with increased cardiovascular (CV) risk.

AIM

To identify additional CV risk factors and early signs of target organ damage in healthy individuals with HNBP.

METHODS

Healthy volunteers (n = 74) with optimal blood pressure or HNBP were compared with respect to metabolic and haemodynamic parameters.

RESULTS

The HNBP was associated with higher serum uric acid (333.1 ± 65.4 vs 267.7 ± 65.4 μmol/L, p < 0.05) and glucose (4.7 ± 0.3 vs 4.5 ± 0.3 mmol/L, p < 0.01) concentrations, intima-media thickness (0.39 ± 0.06 vs 0.36 ± 0.04 mm, p < 0.05), systemic vascular resistance index (2,678.2 ± 955.9 vs 1,930.2 ± 625.5 dyn x s x m(2)/cm(5), p < 0.001), lower total arterial compliance index (1.04 ± 0.42 vs 1.44 ± 0.48 mL/[mm Hg x m(2)], p < 0.01) and baroreflex sensitivity (14.2 ± 3.8 vs 18.0 ± 8.8 mm Hg(2)/Hz, p = 0.05).

CONCLUSIONS

The observed differences in metabolic and haemodynamic profile in HNBP may adversely affect CV risk in these individuals.

Brain vasopressin V(1) receptors contribute to enhanced cardiovascular responses to acute stress in chronically stressed rats and rats with myocardial infarcton

The present study was designed to determine the role of central vasopressin 1 receptors (V(1)R) in the regulation of cardiovascular parameters in chronically stressed infarcted rats and sham-operated rats under resting conditions and during exposure to acute alarming stress. The experiments were performed on four groups of conscious sham-operated and four groups of infarcted rats subjected to intraventricular infusion of either vehicle or a V(1)R antagonist (V(1)RANT). Two groups of infarcted and two groups of sham-operated rats were subjected to mild chronic stressing. Mean arterial blood pressure (MABP) and heart rate (HR) were determined under resting conditions and after exposure to acute stress (air jet). During vehicle infusion, MABP and HR increases in response to acute stress in the infarcted rats not subjected to chronic stress, and in the infarcted and sham-operated chronically stressed rats, were significantly greater than in the sham-operated rats not exposed to chronic stress. However, MABP and HR responses to acute stress in the chronically stressed infarcted rats and chronically stressed sham-operated rats did not differ. V(1)RANT abolished differences in cardiovascular responses to acute stress between the experimental groups. Resting cardiovascular parameters were not affected by any of the experimental treatments. It is concluded that chronic stressing enhances the pressor and tachycardic responses to acute stress in the sham-operated rats but does not further intensify these responses in infarcted rats.The results provide evidence that central V(1)Rs are involved in potentiation of cardiovascular responses to acute stress in chronically stressed rats, infarcted rats, and chronically stressed infarcted rats.

Oxytocin in the cardiovascular responses to stress

The present study was designed to determine the role of central oxytocin (OXY) in regulation of the cardiovascular responses to the alarming stress. Three groups of male, normotensive Sprague Dawley rats, received intracerebroventricular (i.c.v.) infusion of one of the following: 1) vehicle, 2) OXY or 3) OXY antagonist (OXANT). Mean arterial blood pressure (MABP) and heart rate (HR) were recorded at rest, during and after application of the alarming stressor (air jet). Under resting conditions the i.c.v. infusions of vehicle, OXY or OXYANT did not influence the cardiovascular parameters. The alarming stressor evoked significant increases in MABP and HR that were significantly greater in the rats receiving i.c.v. infusion of oxytocin antagonist than in those receiving vehicle or OXY. The study provides evidence that stimulation of the brain oxytocin receptors by endogenous oxytocin plays significant role in inhibition of cardiovascular responses to stress.

Differential sensitisation to central cardiovascular effects of angiotensin II in rats with a myocardial infarct: relevance to stress and interaction with vasopressin

The purpose of the present study was to elucidate if rats with myocardial infarction manifest altered responsiveness to central cardiovascular effects of low doses of angiotensin II (ANG II), and if ANG II and vasopressin (VP) cooperate in the central regulation of cardiovascular functions at rest and during stress. Conscious Sprague-Dawley rats with myocardial infarction induced by left coronary artery ligation, or sham-ligated (SL) controls were infused intracerebroventricularly with artificial cerebrospinal fluid (aCSF), ANG II, ANG II + VP or ANG II + V1a receptor antagonist (V1ANT) 4 weeks after cardiac surgery. In the infarcted but not in the SL rats, the resting mean arterial blood pressure (MABP) was significantly elevated by infusions of ANG II and ANG II + VP, while infusion of ANG II + V1ANT was not effective. During administration of aCSF, the pressor, and tachycardic responses to an air-jet stressor were significantly greater in the infarcted than in the SL rats. In the SL rats, the pressor responses to the stressor were significantly greater during infusions of ANG II, ANG II + VP and ANG II + V1ANT than during infusion of aCSF. The tachycardic response in the SL rats was enhanced only by the combined infusion of ANG II + VP. In the infarcted rats, the pressor and the tachycardic responses to the stressor were similar in all groups. It is concluded that: (1) under resting conditions the infarcted rats manifest sensitisation to the central pressor effect of ANG II and that this effect depends on concomitant stimulation of V1a VP receptors, (2) central ANG II may enhance the pressor response to an alarming stressor in the SL rats through an action which does not depend on the concomitant stimulation of V1a receptors, (3) the cooperative action of ANG II and VP is required for intensification of the tachycardic response to the alarming stressor in the SL rats and (4) exaggeration of the cardiovascular responses to the alarming stressor in the infarcted rats cannot be further augmented by an additional stimulation of central ANG II receptors or combined stimulation of ANG II and VP receptors.

[Myocardial structure and function in patients with metabolic syndrome--echocardiographic and ergospirometric assessment]

Presently a lot of studies focus on metabolic syndrome. There are new studies regarding the relationship between metabolic syndrome (MS) and changes in myocardial structure and function and subsequent development of heart failure. The aim of the study was to assess the myocardial structure and function, particularly diastolic function, and to evaluate the exercise capacity in patients with metabolic syndrome.

MATERIAL AND METHODS

53 patients with MS (defined according to NCEP ATP III criteria) and 33 individuals in control group were enrolled into the study. Echocardiographic examination (with evaluation of morphologic parameters, ejection fraction and diastolic function) and ergospirometry (to objectively assess the exercise capacity) were performed in all patients.

RESULTS

In patients with MS hypertension (100%) and abdominal obesity (98%) were the most frequent. In the studied group significantly lower E/A ratio (describing left ventricle relaxation) was observed in comparison to control group (E/A 1.0 +/- 0.05 vs. 1.29 +/- 0.11; p < 0.05). Diastolic dysfunction assessed with the use of E/A worsened with the number of metabolic syndrome elements (1.07 vs. 0.96 vs. 0.87 for 3, 4 and 5 metabolic syndrome elements respectively). Lower peak oxygen uptake (VO2 peak) was observed in patients with MS in comparison to control group (24 +/- 0.75 vs. 27 +/- 1.52 ml/kg/min; p < 0.05). There was the tendency to higher VE-CO2 slope index in patients with MS in comparison to control group (27 +/- 0.45 vs. 25 +/- 0.7; p = 0.057). VE-CO2 slope increased with the increase of the number of MS elements (26 vs. 28 vs. 29 for 3, 4 and 5 metabolic syndrome elements). There was significant positive correlation between E/A ratio and VO2 peak (r = 0.27; p < 0.05) and significant negative correlation between E/A ratio and VE-CO2 slope (r = -0.37; p < 0.01).

CONCLUSIONS

In patients with metabolic syndrome the significant decrease of exercise capacity assessed by ergospirometry and lower values of E/A ratio (that describes left ventricle relaxation) in comparison to control group. It seems that there is casual relation between these parameters and one may conclude that patients with MS are at risk of development of left ventricle dysfunction and in consequence heart failure.

Interaction of AT1 receptors and V1a receptors-mediated effects in the central cardiovascular control during the post-infarct state

Experimental objectives. Because myocardial infarct is associated with overactivation of brain angiotensin II (ANG II) and vasopressin (AVP) V1a receptors we decided to determine whether AT1 and V1a receptors-mediated effects of ANG II and AVP interact in central cardiovascular control during the post-infarct state. Four groups of infarcted and four groups of sham-operated conscious rats entered the study. Results. In the infarcted rats cerebroventricular infusion of AT1 (AT1ANT, losartan) and V1a antagonist {V1aANT,d(CH(2))(5)[Tyr(Me)(2)Ala-NH(2)(9)]VP} and combined infusion of both these compounds performed 4 weeks after induction of the infarct significantly and comparably reduced mean arterial blood pressure (MABP) in comparison to control experiments (artificial cerebrospinal fluid infusion). In the sham rats MABP was not affected by any of the infusions. In control experiments MABP and HR responses to an alarming air jet stress were significantly higher in the infarcted than in the sham rats. Both responses were normalized with the same effectiveness by administration of AT1ANT, V1aANT and AT1ANT+V1aANT. In the sham rats administration of these compounds did not affect MABP and HR responses to stress.

CONCLUSION

The results provide evidence for interaction of AT1 and V1a receptors-mediated effects of ANG II and AVP in the central cardiovascular control during the post-infarct state.

Haemodynamic responses to the dynamic exercise in subjects exposed to different gravitational conditions

Different types of adaptation of the cardiovascular system to the gravitational forces (hypokinetic and hyperkinetic) have been described in the healthy and the sick subjects under resting conditions. The aim of the present study was to elucidate whether haemodynamic responses to the dynamic exercise performed under various gravitational conditions are determined by the type of adaptation of the cardiovascular system to the gravitational forces at rest. The study was performed on 249 healthy men, 20-60 years old. To assess the type of regulation of the cardiovascular system arterial blood pressure (MABP), heart rate (HR), stroke volume (SV), cardiac output (CO), and systolic function (SF) of the heart were determined in each subject at rest in the upright (orthostatic state) and in the supine position. Subsequently, the subjects were performing exercise on a cycloergometer in the sitting and the supine position. Four gradually increasing workloads were applied. Measurements of HR, MABP, SV, CO, and SF were repeated at the end of each workload. SV, CO and SF were determined by means of rheography. The results revealed that in the individuals showing at rest the hypokinetic type of orthostatic cardiovascular adaptation the augmentation of CO during exercise in the sitting position was caused by significant increases of HR and SV. In contrast, the subjects with the hyperkinetic type of orthostatic adaptation the increase in CO during exercise in the sitting position was much smaller and resulted predominantly from acceleration of HR. It is concluded that the cardiovascular adaptation to the dynamic exercise depends not only on the position of the body in which the exercise is performed but it is also determined by the type of adaptation of the cardiovascular system to the gravitational forces at rest. In the sitting position the pumping capacity of the heart is significantly greater in the hypokinetic than in the hyperkinetic type of the cardiovascular regulation; this relationship being reversed during exercise in the horizontal position.