Cardiorespiratory fitness mediates cortisol and lactate responses to winter and summer marches

Background

The influence of homeostatically regulated physiological processes, including cardiorespiratory fitness (VO2max), on the response to physical stressors such as acclimatisation and marching, remains understudied. We aimed to investigate the effects of summer and winter acclimatisation and marching on cortisol levels and blood lactate, to gain insight into the role of these physiological processes in the stress response.

Methods

Two groups of young Europeans, classified as poor (PCF; n=9) and good physical condition (GCF; n=21), based on a VO2MAX threshold of 40 mL O2/ kg/min, underwent 2-h March (6-7 km/h) in winter (5˚C) and summer (32˚C). Commercial tests, UniCel DxI Access Cortisol assay and EKF Biosen Clinic/GP assay were used for cortisol and lactate blood measurements (morning samples and those taken immediately after marches), respectively.

Sacubitril/valsartan reverses cardiac structure and function in experimental model of hypertension-induced hypertrophic cardiomyopathy

This study evaluated the effect of sacubtril/valsartan on cardiac remodeling, molecular and cellular adaptations in experimental (rat) model of hypertension-induced hypertrophic cardiomyopathy. Thirty Wistar Kyoto rats, 10 healthy (control) and 20 rats with confirmed hypertension-induced hypertrophic cardiomyopathy (HpCM), were used for this study. The HpCM group was further subdivided into untreated and sacubitril/valsartan-treated groups. Myocardial structure and function were assessed using echocardiography, Langendorff's isolated heart experiment, blood sampling and qualitative polymerase chain reaction. Echocardiographic examinations revealed protective effects of sacubitril/valsartan by improving left ventricular internal diameter in systole and diastole and fractional shortening. Additionally, sacubitril/valsartan treatment decreased systolic and diastolic blood pressures in comparison with untreated hypertensive rats. Moreover, sacubitril/valsartan treatment reduced oxidative stress and apoptosis (reduced expression of Bax and Cas9 genes) compared to untreated rats. There was a regular histomorphology of cardiomyocytes, interstitium, and blood vessels in treated rats compared to untreated HpCM rats which expressed hypertrophic cardiomyocytes, with polymorphic nuclei, prominent nucleoli and moderately dilated interstitium. In experimental model of hypertension-induced hypertrophic cardiomyopathy, sacubitril/valsartan treatment led to improved cardiac structure, haemodynamic performance, and reduced oxidative stress and apoptosis. Sacubitril/valsartan thus presents as a potential therapeutic strategy resulted in hypertension-induced hypertrophic cardiomyopathy.

Examining the Effects of Hyperbaric Oxygen Therapy on the Cardiovascular System and Oxidative Stress in Insulin-Treated and Non-Treated Diabetic Rats

BACKGROUND

This study explored the effects of hyperbaric oxygen therapy (HBOT) on the cardiovascular system and oxidative stress in streptozotocin-induced diabetic rats. Wistar albino rats were divided into four groups: DM group (diabetic rats), DM+HBOT group (diabetic rats exposed to HBOT for 1 h daily, five days a week, at 2.8 atmosphere absolute (ATA) with 100% oxygen for two weeks), DM+INS group (diabetic rats treated with neutral protamine hagedorn (NPH) insulin at a dosage of 3-5 U/day), and DM+HBOT+INS group (diabetic rats treated with both NPH insulin and HBOT for two weeks).

METHODS

Evaluations included glycemic control, oxidative stress parameters, and cardiac function measurements.

RESULTS

NPH insulin treatment reduced blood glucose levels, although normoglycemia was not achieved. The DM+HBOT+INS group demonstrated the lowest pro-oxidative marker levels. NPH insulin treatment improved cardiac function, and combination therapy effectively restored cardiac function in diabetic animals.

CONCLUSIONS

NPH insulin treatment reduced hyperglycemia and improved cardiac function in diabetic rats. The combined approach of NPH insulin and HBOT resulted in decreased pro-oxidative markers. These findings provide valuable insights for managing cardiovascular complications and oxidative stress in diabetes.

The Potential of SGLT-2 Inhibitors in the Treatment of Polycystic Ovary Syndrome: The Current Status and Future Perspectives

Polycystic ovary syndrome (PCOS) is the most frequent endocrinopathy during women’s reproductive age. PCOS is a heterogeneous disorder featuring specific cardiometabolic properties. The association between the presence of metabolic disorders and PCOS supports the claim that the regulation of glycemic status is very important in these patients. There is a wide range of therapeutic options (including those treating diabetes mellitus type 2) with potential advantages available for the management of PCOS. Sodium–glucose cotransporter type 2 inhibitors (SGLT-2is) improve glucose metabolism, reduce fat tissue, lower blood pressure, reduce oxidative stress and inflammation, and protect the cardiovascular system. Currently, the use of SGLT-2is is not widespread in PCOS therapy, although these drugs represent a promising new therapeutic approach. Therefore, it is necessary to initiate further study in order to determine more effective therapies for PCOS and investigate the effect of SGLT-2is, both as a monotherapy and in combination with other drugs. It is necessary to understand the mechanisms underlying SGLT-2is in PCOS and their effects on long-term complications, especially since the gold standard treatment for PCOS, such as metformin and oral contraceptives, do not have long-term cardioprotective effects. The effects of SGLT-2is seem to involve cardiac protection, while diminishing endocrine and reproductive abnormalities in PCOS. In the current narrative review, we examine the most recent clinical evidence and discuss the potential applications of SGLT-2is for PCOS therapy.

Short-Term Administration of Lemon Balm Extract Ameliorates Myocardial Ischemia/Reperfusion Injury: Focus on Oxidative Stress

We aimed to investigate the cardioprotective effects of ethanolic Melissa officinalis L. extract (ME) in the rat model of myocardial ischemia/reperfusion (I/R) injury. Thirty-two Wistar rats were randomly divided into a CTRL non-treated control group with myocardial I/R injury and three experimental groups of rats treated with 50, 100, or 200 mg/kg of ME for 7 days per os. Afterward, hearts were isolated, and cardiodynamic function was assessed via the Langendorff model of global 20 min ischemia and 30 min reperfusion. Oxidative stress parameters were determined spectrophotometrically from the samples of coronary venous effluent (O₂⁻, H₂O₂, TBARS, and NO₂⁻,) and heart tissue homogenate (TBARS, NO₂⁻, SOD, and CAT). H/E and Picrosirius red staining were used to examine cardiac architecture and cardiac collagen content. ME improved cardiodynamic parameters and achieved to preserve cardiac architecture after I/R injury and to decrease fibrosis, especially in the ME200 group compared to CTRL. ME200 and ME100 markedly decreased prooxidants TBARS, O₂⁻, and H₂O₂ while increasing NO₂⁻. Hereby, we confirmed the ME`s ability to save the heart from I/R induced damage, even after short-term preconditioning in terms of preserving cardiodynamic alterations, cardiac architecture, fibrosis, and suppressing oxidative stress, especially in dose of 200 mg/kg.

Dose-dependent effects of perfluorocarbon-based blood substitute on cardiac function in myocardial ischemia-reperfusion injury

The main goal of this study was to investigate the cardioprotective properties in terms of effects on cardiodynamics of perfluorocarbon emulsion (PFE) in ex vivo-induced ischemia-reperfusion injury of an isolated rat heart. The first part of the study aimed to determine the dose of 10% perfluoroemulsion (PFE) that would show the best cardioprotective effect in rats on ex vivo-induced ischemia-reperfusion injury of an isolated rat heart. Depending on whether the animals received saline or PFE, the animals were divided into a control or experimental group. They were also grouped depending on the applied dose (8, 12, 16 ml/kg body weight) of saline or PFE. We observed the huge changes in almost all parameters in the PFE groups in comparison with IR group without any pre-treatment. Calculated in percent, dp/dt max was the most changed parameter in group treated with 8 mg/kg, while the dp/dt min, SLVP, DLVP, HR, and CF were the most changed in group treated with 16 mg/kg 10 h before ischemia. The effects of 10% PFE are more pronounced if there is a longer period of time from application to ischemia, i.e., immediate application of PFE before ischemia (1 h) gave the weakest effects on the change of cardiodynamics of isolated rat heart. Therefore, the future of PFE use is in new indications and application methods, and PFE can also be referred to as antihypoxic and antiischemic blood substitute with mild membranotropic effects.

Creatine phosphate administration in cardiac ischemia-reperfusion injury in rats: focus on differences between preconditioning, perconditioning and postconditioning protocol

The aim of this study was to examine and compare the influence of preconditioning, perconditioning and postconditioning with creatine phosphate (PCr) on functional recovery and production of prooxidants of isolated rat heart subjected to ex vivo I-R injury on Langendorff apparatus. Wistar albino rats (male, n=40) were divided into 4 groups: control, and groups in which PCr (0.5mmol/l, 5 minutes) was perfused before (Pre group), after (Post group) or during (Per group) ex vivo induced ischemia. PCr application was associated with the great benefits on preserving cardiac contractility (in Pre group 100.96% for +(dP/dt max), 97.61.% for -(dP/dt max), in Per group 96.72% for +(dP/dt max), 95.60.% for -(dP/dt max) and in Post group 143.84% for +(dP/dt max), 104.36% for -(dP/dt max) in relation to the stabilization). In addition, PCr application prevented the rise of pro-oxidative markers during I-R injury in all therapeutic modalities. The most intensive benefits in the current investigation were observed when PCr was applied during the period of ischemia because the lowest fluctuations in the parameters of cardiac function and oxidative stress were observed. Overall, the results of this study highlight PCr-induced cardioprotection with promising prospects for future clinical use.

New Insight Into the Cardioprotective Effects of Allium ursinum L. Extract Against Myocardial Ischemia-Reperfusion Injury

This study aimed to estimate the effects of increasing doses of Allium ursinum methanol extract on cardiac ischemia/reperfusion injury (I/R) with a special emphasis on the role of oxidative stress. Fifty rats were randomly divided into five groups (10 animals per group) depending on the applied treatment as follows: sham, rats who drank only tap water for 28 days and hearts were retrogradely perfused for 80 min without I/R injury, I/R, rats who drank only tap water for 28 days and hearts were exposed to ex vivo I/R injury and rats who consumed increasing doses of A. ursinum 125, 250, and 500 mg/kg for 28 days before I/R injury. Hearts from all rats were isolated and retrogradely perfused according to the Langendorff technique. Parameters of oxidative stress were spectrophotometrically measured in blood, coronary venous effluent, and heart tissue samples. Intake of wild garlic extract for 28 days significantly contributed to the recovery of cardiac function, which was reflected through preserved cardiac contractility, systolic function, and coronary vasodilatory response after ischemia. Also, wild garlic extract showed the potential to modulate the systemic redox balance and stood out as a powerful antioxidant. The highest dose led to the most efficient decrease in cardiac oxidative stress and improve recovery of myocardial function after I/R injury. We might conclude that wild garlic possesses a significant role in cardioprotection and strong antioxidant activity, which implicates the possibility of its use alone in the prevention or as adjuvant antioxidant therapy in cardiovascular diseases (CVD).

Dipeptidyl peptidase 4 inhibitors attenuate cardiac ischaemia-reperfusion injury in rats with diabetes mellitus type 2

The aim of our study was to assess and compare the effects of dipeptidyl peptidase 4 (DPP4) inhibitors, saxagliptin and sitagliptin, on metabolic control of disease and cardiac function in rats with diabetes mellitus type 2 (T2DM). This research would provide novel understanding into the potentially protective effects of DPP4 inhibitors in helping salvage of the heart exposed to ischaemia-reperfusion (I-R) injury. Forty-eight Wistar albino rats were randomly divided into four groups: CTRL, Control healthy group; T2DM, rats with T2DM; T2DM + Sit, rats with T2DM treated with 0.6 mg/kg of sitagliptin; T2DM + Sax, rats with T2DM treated with 0.45 mg/kg of saxagliptin for 3 weeks. At the end of the protocol, in vivo cardiac function was assessed by echocardiography, while in the blood samples glucose and insulin were determined. Additionally, ex vivo heart function was estimated on a model of I-R injury using Langendorff apparatus. Immunohistochemical analysis was used to determine the degree of myocardial apoptosis and necrosis, while DPP4 staining was performed to assess the cardiac DPP4 expression. Data were analyzed using a one-way analysis of variance (ANOVA) and the post hoc Bonferroni test for multiple comparisons. Improved glycoregulation was noticed in rats that received DPP4 inhibitors compared to untreated diabetic rats (P < .05). Moreover, better in vivo systolic function was observed in rats treated with both DPP4 inhibitors as evidenced by an increase in fractional shortening when compared to T2DM (P < .05). Most parameters of cardiac function in treated rats remained unaltered during reperfusion, thus suggesting that both drugs protected myocardium during flow restoration. Better effects on coronary circulation were achieved after sitagliptin application. Additionally, both DPP4 inhibitors showed similar potential to attenuate cardiac necrosis and apoptosis. Saxagliptin and sitagliptin might be efficient in preserving myocardial function and morphology in ex vivo induced I-R cardiac injury in rats with T2DM.

The influences of chokeberry extract supplementation on redox status and body composition in handball players during competition phase

The aim of our study was to investigate the influence of 12 weeks of consumption of chokeberry extract on redox status, body composition, lipid profile, and biochemical parameters in active handball players. The study included 16 handball players aged 16-24 years (20.26 ± 2.86 years). Every morning before training, players received 30 mL of liquid chokeberry extract for 12 weeks during the regular competition season. The research consisted of morphofunctional and biochemical testing, which was performed at three points (at the beginning of the study and at 6 and 12 weeks after extract consumption). After the chokeberry extract treatment, we observed significant changes in three main aspects. The 12 week supplementation with chokeberry extract decreased the levels of prooxidants (TBARS and nitrites) and increased catalase activity. Analyzing the dynamic of body composition showed a decrease in body fat (9.4 ± 0.5 vs. 7.3 ± 0.6 kg) as well as its percent in a body (11.4 ± 0.4% vs. 8.8 ± 0.4%). On the other hand, the analysis showed an increase of high-density lipoprotein (1.3 ± 0.3 vs. 1.6 ± 0.2 mmol/L) and hemoglobin (144.4 ± 11.7 vs. 151.7 ± 9.9 g/L) after 6 weeks of treatment. At the same time, a decrease in leukocytes (7.2 × 10⁹ ± 2.8 vs. 6.5 ± 1.2 × 10⁹/L) and an increase in red blood cells count (4.9 ± 0.4 × 10⁹ vs. 5.5 ± 0.5 × 10⁹/L) were observed. Overall, these results emphatically show that the use of chokeberry extract dietary supplement induced a wide range of beneficial effects in the examined group of athletes.

Effects of different dietary regimes alone or in combination with standardized Aronia melanocarpa extract supplementation on lipid and fatty acids profiles in rats

This study investigated different dietary strategies, high-fat (HFd), or standard diet (Sd) alone or in combination with standardized Aronia melanocarpa extract (SAE), as a polyphenol-rich diet, and their effects on lipids and fatty acids (FA) in rats with metabolic syndrome (MetS). Wistar albino rats were randomly divided into two groups: healthy and rats with MetS, and then depending on dietary patterns on six groups: healthy rats fed with Sd, healthy rats fed with Sd and SAE, rats with MetS fed with HFd, rats with MetS fed with HFd and SAE, rats with MetS fed with Sd, and rats with MetS fed with Sd and SAE. 4 weeks later, after an overnight fast (12-14 h), blood for determination of total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), index of lipid peroxidation (measured as TBARS), and FA was collected. Increased FA and lipid concentration found in MetS rats were reduced when changing dietary habits from HFd to Sd with or without SAE consumption. Consumption of SAE slightly affects the FA profiles, mostly palmitoleic acid in healthy rats and PUFA in MetS + HFd rats. Nevertheless, in a high-fat diet, SAE supplementation significantly decreases n-6/n-3 ratio, thereby decreasing systemic inflammation. Further researches are warranted to confirm these effects in humans.

The impact of nine weeks swimming exercise on heart function in hypertensive and normotensive rats: role of cardiac oxidative stress

BACKGROUND

The purpose of this study was to estimate the effects of 9-week swimming training on cardiodynamic parameters and coronary flow in a rat model of high salt-induced hypertension with a special focus on the role of oxidative stress.

METHODS

Rats involved in the research were divided randomly into four groups: healthy sedentary (SA), healthy trained (TA), sedentary hypertensive (SHA) and trained hypertensive animals (THA). Trained rats were exposed to 9-week swimming training (5 days/week, 60 min/day). Additionally, in order to induce hypertension animals from SHA and THA groups were on high sodium (8% NaCl solution) diet during 4 weeks. Afterwards all rats were sacrificed and hearts were isolated and retrogradely perfused according to Langendorff technique. The following parameters of cardiac function were continuously recorded: maximum and minimum rate of pressure development in left ventricle, systolic and diastolic left ventricular pressure and heart rate. Coronary flow was measured flowmetrically. Oxidative stress markers were determined in coronary venous effluent.

RESULTS

Our findings demonstrated that 9 weeks of swimming training led to improvement of cardiac contractility, relaxation and systolic capacity of normotensive rats, while this training protocol induced enhanced diastolic function in hypertensive conditions. More pronounced effects of exercise in alleviating oxidative stress were observed in hypertensive rats.

CONCLUSIONS

Obvious beneficial exercise-induced cardiac adaptations provide scientific basis for further researches which would thoroughly clarify the mechanisms through which swimming training alters myocardial function both in healthy conditions and in the presence of chronic diseases.

Correlation between oxidative stress and G6PD activity in neonatal jaundice

Fetal distress represents a pathophysiological condition in which oxygen is not available to the fetus in sufficient quantities. In cases of glucose 6-phosphate dehydrogenase (G6PD) deficiency, under conditions of oxidative stress, the residual G6PD and complimentary antioxidant mechanisms may become insufficient to neutralize the large amounts of ROS and to prevent severe hemolysis. Alteration in the oxidant-antioxidant profile is also known to occur in neonatal jaundice. The study group included 22 neonates presented with fetal distress during labor and 24 neonates with no evidence of fetal distress (control group). Umbilical cord blood samples were taken immediately after delivery, and the following blood tests were carried out after birth and at discharge from the hospital: erythrocyte count, total bilirubin, G6PD activity, and parameters presenting oxidative status [thiobarbituric acid reactive substances (TBARS), NO, O2 (-), H2O2, SOD, CAT, O2 (-)/SOD, and H2O2/CAT]. There were no significant differences in TBARS and NO values among neonates with or without fetal distress. However, the values of O2 (-), H2O2, SOD, O2 (-)/SOD, and H2O2/CAT among neonates born after fetal distress were significantly higher than in neonates without fetal distress (p < 0.01). In neonates with fetal distress, the total number of RBCs at delivery was significantly lower, accompanied with higher bilirubin content. Also neonates with fetal distress had lower activity of G6PD and lower CAT activity. Higher values of oxidative stress parameters in newborns delivered after fetal distress do not indicate strictly what occurred first-oxidative stress or basic lower G6PD activity.

[Carbon dioxide--a universal inhibitor of the generation of active oxygen forms by cells (deciphering one enigma of evolution)]

Studies were carried out on blood phagocytes and alveolar macrophages of 96 humans, on the cells of the viscera and tissue phagocytes (liver, brain, myocardium, lungs, kidneys, stomach, and skeletal muscle), and liver mitochondria of 186 random bred white mice. Generation of the active oxygen forms was determined using different methods after direct effect of CO2 on the cells and biopsies and indirect effect of CO2 on the integral organism. The results obtained suggest that CO2 at a tension close to that observed in the blood (37.0 mm Hg) and high tensions (60 or 146 mm Hg) is a potent inhibitor of generation of the active oxygen forms by the cells and mitochondria of the human and tissues. The mechanism of CO2 effect appears to be realized, partially, through inhibition of the NADPH-oxidase activity. The results are important for deciphering of a paradox of evolution, life preservation upon appearance of oxygen in the atmosphere and succession of anaerobiosis by aerobiosis, and elucidation of some other problems of biology and medicine, as well as analysis of the global bioecological problem, such as ever increasing CO2 content in the atmosphere.

[Ability of carbon dioxide to inhibit generation of superoxide anion radical in cells and its biomedical role]

The study was carried out on blood phagocytes and alveolar macrophages of 96 persons, cells of inner organs and tissue phagocytes (liver, brain, myocardium, lungs, kidneys, stomach, skeletal muscles), as well as on mitochondria of the liver of 186 non-linear white mice. Generation of active oxygen forms (AOF) was evaluated by various methods with CO2 directly affecting the cells and bioptates and indirectly the whole organism. The results show that CO2 with tension close to that of the blood (37.0 mm Hg) and at higher tensions (60 and 146 mm Hg) is a powerful inhibitor of AOF generation by human and animal cells, as well as by liver mitochondria of mice. The data obtained allow to explain, in terms of AOF role, a number of physiological and pathophysiological (medical) CO2 effects.

[Comparative study of the effect of carbon dioxide on the generation of active forms of oxygen by leukocytes in health and in bronchial asthma]

The study was conducted by using leukocytes isolated from 74 apparently healthy donors and 60 patients with bronchial asthma. The generation of active oxygen forms was determined by luminolo- and lucigenin-dependent chemiluminescence techniques and NTC-reaction. The findings suggest that at the tension close to the blood tension of 37.5 mm Hg and the high tension of 146 mm Hg is a powerful natural inhibitor of leukocytic generation of active oxygen forms. At an exacerbation, the inhibitory effect of carbon dioxide on the leukocytic generation of active oxygen forms decreased in most (70%) patients with bronchial asthma, which potentiates the free radical mechanism of development of bronchial asthma. It may be held that the literature-described use of carbon dioxide for the treatment of bronchial asthma is justifiable only in a lower proportion of patients who have preserved a high sensitivity to the inhibitory effect of carbon dioxide on the generation of active oxygen forms.