Enhancement Of Endothelial Function Research Articles

Enhancement of endothelial function and attenuation of portal vein injury using mesenchymal stem cells carrying miRNA-25-3p

The aims of this study were to determine whether human umbilical cord mesenchymal stem cells (hucMSCs) modified by miRNA-25-3p (miR-25-3p) overexpression could promote venous endothelial cell proliferation and attenuate portal endothelial cell injury. HucMSCs and human umbilical vein endothelial cells (HUVEC) were isolated and cultured from human umbilical cord and characterized. Lentiviral vectors expressing miRNA-25-3p were transfected into hucMSCs and confirmed by PCR. We verified the effect of miR-25-3p-modified hucMSCs on HUVEC by cell co-culture and cell supernatant experiments. Subsequently, exosomes of miR-25-3p-modified hucMSCs were isolated from cell culture supernatants and characterized by WB, NTA and TEM. We verified the effects of miR-25-3p-modified exosomes derived from hucMSCs on HUVEC proliferation, migration, and angiogenesis by in vitro cellular function experiments. Meanwhile, we further examined the downstream target genes and signaling pathways potentially affected by miR-25-3p-modified hucMSC-derived exosomes in HUVEC. Finally, we established a rat portal vein venous thrombosis model by injecting CM-DiR-labeled hucMSCs intravenously into rats and examining the homing of cells in the portal vein by fluorescence microscopy. Histological and immunohistochemical experiments were used to examine the effects of miRNA-25-3p-modified hucMSCs on the proliferation and damage of portal vein endothelial cells. Primary hucMSCs and HUVECs were successfully isolated, cultured and characterized. Primary hucMSCs were modified with a lentiviral vector carrying miR-25-3p at MOI 80. Co-culture and cell supernatant intervention experiments showed that overexpression of miRNA-25-3p in hucMSCs enhanced HUVEC proliferation, migration and tube formation in vitro. We successfully isolated and characterized exosomes of miR-25-3p-modified hucMSCs, and exosome intervention experiments demonstrated that miR-25-3p-modified exosomes derived from hucMSCs similarly enhanced the proliferation, migration, and angiogenesis of HUVECs. Subsequent PCR and WB analyses indicated PTEN/KLF4/AKT/ERK1/2 as potential pathways of action. Analysis in a rat portal vein thrombosis model showed that miR-25-3p-modified hucMSCs could homing to damaged portal veins. Subsequent histological and immunohistochemical examinations demonstrated that intervention with miR-25-3p overexpression-modified hucMSCs significantly reduced damage and attenuated thrombosis in rat portal veins. The above findings indicate suggest that hucMSCs based on miR-25-3p modification may be a promising therapeutic approach for use in venous thrombotic diseases.

Impact of moderate-intensity aerobic exercise in combined hypoxic and hot conditions on endothelial function.

There is no study that has investigated the impact of exercise in a combined hypoxic and hot environment on endothelial function. Therefore, we tested whether aerobic exercise in a combined hypoxic and hot conditions induces further enhancement of endothelial function. Twelve healthy males cycled at a constant workload (50% of their maximal oxygen uptake under normoxic/thermoneutral conditions) for 30 min in four different environments: exercise under normoxic condition (NOR: fraction of inspiratory oxygen or FiO2 = 20.9%, 20°C), exercise under hypoxic condition (HYP: FiO2 = 14.5%, 20°C), exercise under hot condition (HOT: FiO2 = 20.9%, 30°C), and exercise under combined hypoxia and hot conditions (HH: FiO2 = 14.5%, 30°C). Before, during, and after exercise, cardiovascular variables (e.g., heart rate, blood flow, and shear rate), blood variables, and endothelial function evaluated by flow-mediated dilation (FMD) were assessed. Heart rates were significantly higher throughout the HH trial's experimental period than the other trials (p < 0.05). However, in the HH trial, brachial artery blood flow and shear rate did not differ from those in other trials after exercise. Plasma catecholamines (epinephrine, norepinephrine, and dopamine) elevations in response to exercise were significantly higher in the HH trial than in the other three trials (p < 0.05). No considerable differences were observed in FMD responses among trials before and after the exercise. In conclusion, aerobic exercise in a combined hot and hypoxic environment further activated sympathetic nervous activity but did not considerably enhance blood flow, shear rate, or endothelial function.

Mediterranean diet and health status: Active ingredients and pharmacological mechanisms.

The Mediterranean diet (MedDiet) is one of the most widely described and evaluated dietary patterns in scientific literature. It is characterized by high intakes of vegetables, legumes, fruits, nuts, grains, fish, seafood, extra virgin olive oil, and a moderate intake of red wine. A large body of observational and experimental evidence suggests that higher adherence to the MedDiet is associated with lower risk of mortality, cardiovascular disease, metabolic disease, and cancer. Current mechanisms underlying the beneficial effects of the MedDiet include reduction of blood lipids, inflammatory and oxidative stress markers, improvement of insulin sensitivity, enhancement of endothelial function, and antithrombotic function. Most likely, these effects are attributable to bioactive ingredients such as polyphenols, monounsaturated and polyunsaturated fatty acids, or fibre. This review will focus on both established and less established mechanisms of action of biochemical compounds contained in a MedDiet. LINKED ARTICLES: This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc.

N-3 fatty acids as preventive and therapeutic agents in attenuating PCOS complications.

To our knowledge, in spite of several trials exploring the beneficial effect of n-3 polyunsaturated fatty acids (PUFA) on polycystic ovary syndrome (PCOS), no comprehensive evidence has investigated the effects of n-3 PUFA consumption on PCOS complications. Therefore, our aim was to conduct a review to investigate the possible effect and related mechanisms. A comprehensive systematic search was conducted in Embase, MEDLINE/PubMed, Google Scholar, and SCOPUS, to identify studies investigating n-3 fatty acids as a preventative or therapeutic agent for the attenuation of PCOS complications. Subsequently, the impact of omega-3 on PCOS, omega-3 and inflammation, omega-3 and insulin resistance, omega-3 and adipokines, omega-3 and lipid metabolism, omega-3 and endothelial function and omega-3 and hormonal factors were discussed. There are multiple mechanisms by which n-3 PUFAs may exert their beneficial effects on PCOS, including anti-obesity, glycemic and hormonal hemostasis, anti-inflammatory, regulation of adipokine production and enhancement of endothelial function. N-3 PUFAs are a promising agent in relieving complications associated with PCOS. Although most of the studies in patients with PCOS reported an improvement in most complications after administration of omega-3 supplements, there is a distinct dearth of studies investigating the dietary intake of these types of fatty acids. Moreover, favorable effects regarding the improvement of dyslipidemia, regulation of adipokines, regulation of hormonal factors and enhancement of endothelial function are limited. Therefore, more trials are warranted to investigate palatable mechanisms for clarifying the metabolic and hormonal effects of these agents in PCOS.

Chronic exercise impairs nitric oxide pathway in rabbit carotid and femoral arteries.

Some of the beneficial effects of exercise in preventing vascular related diseases are mediated by the enhancement of endothelial function where the role of nitric oxide (NO) is well documented, although the relevance of calcium activated potassium channels is not fully understood. The impact of oxidative stress induced by training on endothelial function remains to be clarified. By evaluating different endothelial vasodilator pathways on two vascular beds in a rabbit model of chronic exercise, we found a decreased NO bioavailability and endothelial nitric oxide synthase expression in both carotid and femoral arteries. Physical training induced carotid endothelial dysfunction as a result of an increase in oxidative stress and a reduction in superoxide dismutase expression. In the femoral artery, the lower production of NO was counteracted by an increased participation of large conductance calcium activated potassium channels, preventing endothelial dysfunction. The present study aimed to evaluate the effects of chronic exercise on vasodilator response in two different arteries. Rings of carotid and femoral arteries from control and trained rabbits were suspended in organ baths for isometric recording of tension. Endothelial nitric oxide synthase (eNOS), Cu/Zn and Mn-superoxide dismutase (SOD), and large conductance calcium activated potassium (BKCa) channel protein expression were measured by western blotting. In the carotid artery, training reduced the relaxation to ACh (10-9 to 3×10-6 m) that was reversed by N-acetylcysteine (10-3 m). l-NAME (10-4 m) reduced the relaxation to ACh in both groups, although the effect was lower in the trained group (in mean ± SEM, 39±2% vs. 28±3%). Physical training did not modify the relaxation to ACh in femoral arteries, although the response to l-NAME was lower in the trained group (in mean ± SEM, 41±5% vs. 17±2%). Charybdotoxin (10-7 m) plus apamin (10-6 m) further reduced the maximal relaxation to ACh only in the trained group. The remaining relaxation in both carotid and femoral arteries was abolished by KCl (2×10-2 m) and BaCl2 (3×10-6 m) plus ouabain (10-4 m) in both groups. Physical training decreased eNOS expression in both carotid and femoral arteries and Cu/Zn and Mn-SOD expression only in the carotid artery. BKCa channels were overexpressed in the trained group in the femoral artery. In conclusion, chronic exercise induces endothelial dysfunction in the carotid artery as a result of oxidative stress. In the femoral artery, it modifies the vasodilator pathways, enhancing the participation of BKCa channels, thus compensating for the impairment of NO-mediated vasodilatation.

Flow-Mediated Vasodilation Is Not Attenuated in Hypertensive Pregnancies Despite Biochemical Signs of Inflammation

Background. Our objective was to evaluate endothelial function and markers of inflammation during and after pregnancy in normal pregnancies compared to pregnancies complicated with hypertension or preeclampsia (PE). Methods and Results. We measured endothelium-dependent brachial artery flow-mediated vasodilation (FMD) and high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), and tumour necrosis factor-α (TNF-α) in 32 women with normal pregnancy and in 28 women whose pregnancy was complicated with hypertensive disorder in the second half of pregnancy and minimum 3-month postpartum. Enhancement of endothelial function was greater in hypertensive than normal pregnancies, the mean FMD% being 11.0% versus 8.8% during pregnancy (P = 0.194) and 8.0% versus 7.9% postpartum (P = 0.978). Concentrations of markers of inflammation were markedly increased in pregnant hypertensive group compared to those after delivery (hsCRP 4.5 versus 0.80 mg/L, P = 0.023, IL-6 2.1 versus 1.2 pg/mL, P = 0.006; TNF-α 1.9 versus 1.5 pg/mL, P = 0.030). There were no statistically significant associations between the markers of inflammation and FMD. Conclusions. Brachial artery FMD was not attenuated in the third trimester hypertensive pregnancies compared to normal pregnancies, whereas circulating concentrations of hsCRP and IL-6 and TNF-α reacted to hypertensive complications.

Peripheral artery disease: can enhanced vascular reactivity jumpstart the effectiveness of exercise training?

Peripheral arterial disease is a chronic disease with significant cardiovascular risk. Patients with peripheral artery disease experience pain in leg muscles during walking which is only relieved by rest (intermittent claudication) (Stewart et al. 2002; Prior et al. 2004). The goal of treatment in patients is to improve quality of life by minimizing ischaemic symptoms and preventing progression to vascular occlusion. Therapeutic strategies, including exercise-based interventions and exercise training, have been reported to increase pain-free walking and quality of life in these patients (Stewart et al. 2002; Watson et al. 2008). Meta-analysis has shown that the greatest improvements in walking occur when exercise sessions are of at least 30 min in length and when these sessions occur a minimum of two times per week (Gardner & Poehlman, 1995). Thus, the effectiveness of exercise as a therapeutic intervention may be limited if ischaemic pain prevents patients from performing exercise of sufficient length and frequency. Interventions that ‘jumpstart’ the benefits of exercise training by reducing ischaemic pain during initial training bouts could enhance the overall effectiveness of exercise therapy. In a recent issue of The Journal of Physiology, Colleran et al. (2010) report that exercise training, in addition to contributing to remodelling of collateral-dependent arteries, promotes endothelial function and vasodilatory responsiveness. If the mechanism(s) by which exercise training enhances endothelial function in collateral-dependent arteries can be identified, therapeutic interventions could be designed to reduce ischaemia during initial bouts of exercise training, thereby increasing exercise duration and promoting adherence to training by reducing ischaemic pain. Studies involving experimental animal models of peripheral artery disease have demonstrated the presence of a collateral circuit capable of circumventing the vascular obstruction in the lower limb (Yang et al. 1996, 2008); the conductance of this circuit increases following occlusion of a primary hind limb artery. Exercise training has been shown to enhance blood flow through this collateral circuitry in animal models of occlusive artery disease (Yang et al. 1996, 2008). Improvements in collateral-dependent blood flow to hindlimb muscles that occur with exercise training in these occlusive models are accompanied by remodelling and enlargement of collateral vessels. Much of the functional improvement that occurs with exercise training in the occluded hindlimb has been attributed to enlargement of these collateral vessels, presumably stimulated by increases in shear stress during periods of activity (Prior et al. 2004); however, the ability of exercise to alter the reactivity of collateral vessels has remained relatively unexplored. Colleran et al. (2010) present results from a study in which vascular reactivity of collateral vessels from the occluded hindlimb was assessed following 3 weeks of exercise training. They report that exercise enhanced vasodilatory responses to both acetylcholine and flow in peripheral collateral arteries. Exercise training has been reported to enhance endothelium-dependent vasodilatation of skeletal muscle arteries and arterioles in the absence of occlusion (Spier et al. 2004). Colleran et al. (2010) have reported that exercise training increases endothelial reactivity in collateral-dependent arteries, even when assessed at a low intraluminal pressure of 45 cmH2O, approximating conditions present distal to an occlusion. These results suggest that exercise training provides a stimulus sufficient to alter endothelial function even under conditions of reduced intravascular pressure. Importantly, the exercise training-induced improvement in flow-induced vasodilatation of peripheral collateral arteries persisted even in the presence of blockade of both nitric oxide synthase and cyclooxygenase pathways, suggesting that an alternative pathway contributes to the exercise training-induced enhancement of endothelial function in collateral arteries. This differs from reports that implicate nitric oxide signalling as the primary target of exercise training in skeletal muscle arteries and arterioles (Spier et al. 2004). The results of the study by Colleran et al. (2010) indicate that for a complete understanding of the role played by collateral vessels in exercise-induced amelioration of hindlimb bloodflow, careful examination of endothelial signalling pathways must occur. Indeed, if these pathways are carefully evaluated, the benefits of exercise training could be augmented by combined therapy which enhances endothelial function of collateral-dependent vessels in patients that experience significant ischaemic pain during bouts of exercise. Therapeutic intervention targeting these endothelial pathways might also benefit patients who are unable to perform exercise due to overwhelming pain.

Enhancement of endothelial function by pregnancy: inadequate response in women with type 1 diabetes.

Pregnant women with type 1 diabetes have a substantially increased risk of vascular complications. Our aim was to study vascular function and metabolic and inflammatory risk factors during the antenatal and postpartum periods in women with type 1 diabetes compared with healthy control subjects. A total of 15 women with diabetes and 30 control subjects were recruited in the third trimester of pregnancy. Of these women, 9 case subjects and 16 control subjects were reinvestigated in the postnatal period. Blood samples were collected and microvascular skin perfusion was assessed in vivo using laser Doppler imaging and iontophoretic administration of endothelial-dependent (acetylcholine [ACH]) and endothelial-independent (sodium nitroprusside [SNP]) vasodilators. Microvascular responses in both control subjects (ACH, P = 0.018; SNP, P = 0.01) and diabetic women (ACH, P = 0.029; SNP, P = 0.105) were better during pregnancy than in the postnatal period, although responses in women with diabetes were significantly inferior to those in control subjects during both periods (all P < 0.001, two-way ANOVA). This dysfunction existed despite similar lipoprotein profiles. The difference in vascular responsivity between case and control subjects was significantly attenuated by adjustment for differences in HbA(1c) but not C-reactive protein concentrations in the two groups. Pregnancy enhances microvascular function, but in women with diabetes, such improvements are insufficient to attain responses seen in healthy nonpregnant women. This suggests a persistent vascular defect in young women with type 1 diabetes that may contribute to adverse pregnancy outcome. Our data suggest a role for the chronic effects of hyperglycemia in the impaired vascular responsiveness in such women.

Fish oil improves endothelium-dependent coronary vasodilation in heart transplant recipients

Objectives. The purpose of this study was to determine whether dietary fish oil supplementation enhances endothelium-mediated vasodilator responses in human heart transplant recipients, a group known to have coronary artery disease and endothelial dysfunction.Background. Omega-3 fatty acid supplementation has been shown to enhance endothelium-dependent coronary vasodilation in animal models of atherosclerosis,Methods. Endothelium-dependent vasodilator responses to intracoronary acetylcholine infusion and endothelium-independent responses to nitroglycerin were evaluated in heart transplant recipients who received a high dose of dietary supplementation with omega-3 fatty acids for 3 weeks (5 g of eicosapentaenoic acid plus docosahexacnoic acid/day, n = 7) and compared with responses in a group of matched heart transplant recipients who did not receive fish oil (control patients, n = 7). Acetylcholine was selectively infused into the midportion of the left anterior descending or left circumflex coronary artery, with the noninfused left coronary artery serving as a control vessel. Serial coronary angiograms were performed after infusion with increasing doses of acetylcholine (infused concentrations 10−6to 10−3mol/liter) and after intracoronary nitroglycerin administration.Results. The patients treated with fish oil showed a normal vasodilator response to acetylcholine with 14 ± 2.5% and 15 ± 7% vasodilation (vs. baseline diameter) at infused acetylcholine concentrations of 10−5and 10−4mol/liter, respectively. In contrast, the control patients demonstrated vasoconstrictor responses (−1 ± 1% and −9 ± 4%) to acetylcholine at these same doses (p < 0.05 and < 0.005, respectively, for treated vs. control patients). There were no differences in the response to nitroglycerin between the control and treated patients.Conclusions. Dietary supplementation with fish oil significantly alters endothelium-dependent coronary vasodilation in heart transplant recipients without alteration of the responses to endothelium-independent vasodilation. Whether this enhancement of endothelial function can beneficially alter the natural history of heart transplant atherosclerosis warrants further study.