Browsing by Author "Djokic, Vladimir (57194103231)"

Gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH) can jeopardize mother and/or fetus. Vascular ATP-sensitive potassium (KATP) channels most likely participate in the processes of diabetes and hypertension. The aim of this research was to examine whether GDM and PIH cause changes in the expression and function of KATP channels in vascular smooth muscle of human umbilical vein (HUV). Western blot and immunohistochemistry detected significantly decreased expression of Kir6.1 subunit of KATP channels in GDM and PIH, while the expression of SUR2B was unchanged. In GDM, a K+ channel opener, pinacidil caused reduced relaxation of the endothelium-denuded HUVs compared to normal pregnancy. However, its effects in HUVs from PIH subjects were similar to normal pregnancy. In all groups KATP channel blocker glibenclamide antagonized the relaxation of HUV induced by pinacidil without change in the maximal relaxations indicating additional KATP channel-independent mechanisms of pinacidil action. Iberiotoxin, a selective antagonist of large-conductance calcium-activated potassium channels, inhibited the relaxant effect of pinacidil in PIH, but not in normal pregnancy and GDM. Experiments performed in K+-rich solution confirmed the existence of K+-independent effects of pinacidil, which also appear to be impaired in GDM and PIH. Thus, the expression of KATP channels is decreased in GDM and PIH. In GDM, vasorelaxant response of HUV to pinacidil is reduced, while in PIH it remains unchanged. It is very likely that KATP channels modulation and more detailed insight in KATP channel-independent actions of pinacidil may be precious in the therapy of pathological pregnancies. © 2019 Elsevier Inc.

Gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH) can jeopardize mother and/or fetus. Vascular ATP-sensitive potassium (KATP) channels most likely participate in the processes of diabetes and hypertension. The aim of this research was to examine whether GDM and PIH cause changes in the expression and function of KATP channels in vascular smooth muscle of human umbilical vein (HUV). Western blot and immunohistochemistry detected significantly decreased expression of Kir6.1 subunit of KATP channels in GDM and PIH, while the expression of SUR2B was unchanged. In GDM, a K+ channel opener, pinacidil caused reduced relaxation of the endothelium-denuded HUVs compared to normal pregnancy. However, its effects in HUVs from PIH subjects were similar to normal pregnancy. In all groups KATP channel blocker glibenclamide antagonized the relaxation of HUV induced by pinacidil without change in the maximal relaxations indicating additional KATP channel-independent mechanisms of pinacidil action. Iberiotoxin, a selective antagonist of large-conductance calcium-activated potassium channels, inhibited the relaxant effect of pinacidil in PIH, but not in normal pregnancy and GDM. Experiments performed in K+-rich solution confirmed the existence of K+-independent effects of pinacidil, which also appear to be impaired in GDM and PIH. Thus, the expression of KATP channels is decreased in GDM and PIH. In GDM, vasorelaxant response of HUV to pinacidil is reduced, while in PIH it remains unchanged. It is very likely that KATP channels modulation and more detailed insight in KATP channel-independent actions of pinacidil may be precious in the therapy of pathological pregnancies. © 2019 Elsevier Inc.

Climate change is considered to have great impact on human health. The heat waves have been associated with excess morbidity and mortality of cardiovascular diseases (CVD) across various populations and geographic locations. Important role in the heat-induced cardiovascular damage has endothelial dysfunction. It has been noticed that hot weather can impair tone and structure of the blood vessels via interfering with variety of biological factors such as nitric oxide synthesize, cytokine production and systemic inflammation. Also, due to dehydration and increased blood viscosity, by promoting thrombogenesis, heat has important impact on patients with atherosclerosis. During chronic exposure to the cold or hot weather cardiovascular function can be decreased, leading to a higher risk of developing heart attack, malignant cardiac arrhythmias, thromboembolic diseases and heat-induced sepsis like shock. It has been shown that changes in the ambient temperature through increasing blood pressure, blood viscosity, and heart rate, contribute to the cardiovascular mortality. The majority of deaths due to heat waves especially affect individuals with preexisting chronic CVD. This population can experience a decline in the health status, since extreme ambient temperature affects pharmacokinetic parameters of many cardiovascular drugs. Increased mortality from ischemic or hemorrhagic stroke can also be related to extreme temperature variations. On a cellular level, higher ambient temperature can limit storage of ATP and O2increase amount of free radicals and toxic substances and induce neuronal apoptotic signal transduction, which all can lead to a stroke. Preserving cardiovascular function in context of extreme climate changing tends to be particularly challenging. © 2020 Taylor & Francis Group, LLC.

Climate change is considered to have great impact on human health. The heat waves have been associated with excess morbidity and mortality of cardiovascular diseases (CVD) across various populations and geographic locations. Important role in the heat-induced cardiovascular damage has endothelial dysfunction. It has been noticed that hot weather can impair tone and structure of the blood vessels via interfering with variety of biological factors such as nitric oxide synthesize, cytokine production and systemic inflammation. Also, due to dehydration and increased blood viscosity, by promoting thrombogenesis, heat has important impact on patients with atherosclerosis. During chronic exposure to the cold or hot weather cardiovascular function can be decreased, leading to a higher risk of developing heart attack, malignant cardiac arrhythmias, thromboembolic diseases and heat-induced sepsis like shock. It has been shown that changes in the ambient temperature through increasing blood pressure, blood viscosity, and heart rate, contribute to the cardiovascular mortality. The majority of deaths due to heat waves especially affect individuals with preexisting chronic CVD. This population can experience a decline in the health status, since extreme ambient temperature affects pharmacokinetic parameters of many cardiovascular drugs. Increased mortality from ischemic or hemorrhagic stroke can also be related to extreme temperature variations. On a cellular level, higher ambient temperature can limit storage of ATP and O2increase amount of free radicals and toxic substances and induce neuronal apoptotic signal transduction, which all can lead to a stroke. Preserving cardiovascular function in context of extreme climate changing tends to be particularly challenging. © 2020 Taylor & Francis Group, LLC.

The effect of resveratrol on vasculature of diabetic animal is not defined. This study was aimed at evaluating how alloxan-induced diabetes alters the relaxation of the isolated rat renal artery (RA) to resveratrol and determining whether prolong hyperglycemia modifies the expression of potassium (K) channels in the wall of RA. Diabetes reduced the sensitivity to resveratrol in RA. According to K channel blocker affinity, it seems that different subtype of K channels were involved in the resveratrol-induced relaxation of RA of normal rats and only voltage-sensitive Kv1 channels took part in the resveratrol effect on the RA of diabetic rats. Endothelial dysfunction developed during diabetes led to down-regulation of the expression of almost all tested K channels, while up-regulation of Kv1.3 channel expression was only noticeable. Having in mind that Kv1.3 channels have a prominent role in insulin signalling, these results suggest renovascular protective effect of resveratrol in diabetes. © 2018 Elsevier Ltd

The effect of resveratrol on vasculature of diabetic animal is not defined. This study was aimed at evaluating how alloxan-induced diabetes alters the relaxation of the isolated rat renal artery (RA) to resveratrol and determining whether prolong hyperglycemia modifies the expression of potassium (K) channels in the wall of RA. Diabetes reduced the sensitivity to resveratrol in RA. According to K channel blocker affinity, it seems that different subtype of K channels were involved in the resveratrol-induced relaxation of RA of normal rats and only voltage-sensitive Kv1 channels took part in the resveratrol effect on the RA of diabetic rats. Endothelial dysfunction developed during diabetes led to down-regulation of the expression of almost all tested K channels, while up-regulation of Kv1.3 channel expression was only noticeable. Having in mind that Kv1.3 channels have a prominent role in insulin signalling, these results suggest renovascular protective effect of resveratrol in diabetes. © 2018 Elsevier Ltd