Effects of Cardiotoxins from Naja oxiana Cobra Venom on Rat Heart Muscle and Aorta: A Comparative Study of Toxin-Induced Contraction Mechanisms.

Cardiotoxins (CaTxs) are a group of snake toxins that affect the cardiovascular system (CVS). Two types (S and P) of CaTxs are known, but the exact differences in the effects of these types on CVS have not been thoroughly studied. We investigated cellular mechanisms of action on CVS for Naja oxiana cobra CaTxs CTX-1 (S-type) and CTX-2 (P-type) focusing on the papillary muscle (PM) contractility and contraction of aortic rings (AR) supplemented by pharmacological analysis. It was found that CTX-1 and CTX-2 exerted dose-dependent effects manifested in PM contracture and AR contraction. CTX-2 impaired functions of PM and AR more strongly than CTX-1. Effects of CaTxs on PM were significantly reduced by nifedipine, an L-type Ca2+ channel blocker, and by KB-R7943, an inhibitor of reverse-mode Na+/Ca2+ exchange. Furthermore, 2-aminoethoxydiphenyl borate, an inhibitor of store-operated calcium entry, partially restored PM contractility damaged by CaTxs. The CaTx influence on AR contracture was significantly reduced by nifedipine and KB-R7943. The involvement of reverse-mode Na+/Ca2+ exchange in the effect of CaTxs on the rat aorta was shown for the first time. The results obtained indicate that CaTx effects on CVS are mainly associated with disturbance of transporting systems responsible for the Ca2+ influx.

Combined inorganic nitrate/nitrite supplementation blunts α-mediated vasoconstriction during exercise in patients with type 2 diabetes.

AIMS: Patients with type 2 diabetes mellitus (T2DM) have reduced vasodilatory responses during exercise partially attributable to low nitric oxide (NO) levels. Low NO contributes to greater α-adrenergic mediated vasoconstriction in contracting skeletal muscle. We hypothesized boosting NO bioavailability via 8wks of active beetroot juice (BRA, 4.03 mmol nitrate, 0.29 mmol nitrite, n = 19) improves hyperemia, via reduced α-mediated vasoconstriction, during handgrip exercise relative to nitrate/nitrite-depleted beetroot juice (BRP, n = 18) in patients with T2DM. METHODS: Forearm blood flow (FBF) and vascular conductance (FVC) were calculated at rest and during handgrip exercise (20%max, 20contractions·min-1). Phenylephrine (α1-agonist) and dexmedetomidine (α2-agonist) were infused intra-arterially during independent trials to determine the influence of α-mediated vasoconstriction on exercise hyperemia. Vasoconstriction was quantified as the percent-reduction in FVC during α-agonist infusion, relative to pre-infusion, as well as the absolute change in %FVC during exercise relative to the respective rest trial (magnitude of sympatholysis). RESULTS: ΔFBF (156 ± 69 to 175 ± 73 ml min-1) and ΔFVC (130 ± 54 to 156 ± 63 ml min-1·100 mmHg-1, both P < 0.05) during exercise were augmented following BRA, but not BRP (P = 0.96 and 0.51). Phenylephrine-induced vasoconstriction during exercise was blunted following BRA (-17.1 ± 5.9 to -12.6 ± 3.1%, P < 0.01), but not BRP (P = 0.58) supplementation; the magnitude of sympatholysis was unchanged by either (beverage-by-time P = 0.15). BRA supplementation reduced dexmedetomidine-induced vasoconstriction during exercise (-23.3 ± 6.7 to -19.7 ± 5.2%) and improved the corresponding magnitude of sympatholysis (25.3 ± 11.4 to 34.4 ± 15.5%, both P < 0.05). CONCLUSIONS: BRA supplementation improves the hyperemic and vasodilatory responses to exercise in patients with T2DM which appears to be attributable to reduced α-adrenergic mediated vasoconstriction in contracting skeletal muscle.

Marjoram extract prevents ischemia reperfusion-induced myocardial damage and exerts anti-contractile effects in aorta segments of male wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Marjoram (Origanum majorana L.) is an herb traditionally used as a medicine in different countries, as Morocco and Iran, because of its beneficial cardiovascular effects. Some studies suggest that these effects are due, at least in part, to the presence of phenolic compounds such as rosmarinic acid (RA) and luteolin. AIM OF THE STUDY: To analyze the possible cardiprotective effects of a marjoram extract (ME) reducing myocardial damage after coronary ischemia-reperfusion (IR) and its possible antihypertensive effects reducing the response of aorta segments to the vasoconstrictors noradrenaline (NA) and endothelin-1 (ET-1). MATERIALS AND METHODS: Male Wistar rats (300g) were used. After sacrifice, the heart was immediately removed and mounted in a perfusion system (Langendorff). The aorta was carefully dissected and cut in 2 mm segments to perform vascular reactivity experiments. RESULTS: In the heart, ME perfusion after IR reduced heart rate and prevented IR-induced decrease of cardiac contractility, possibly through vasodilation of coronary arteries and through the upregulation of antioxidant markers in the myocardium that led to reduced apoptosis of cardiomyocytes. In the aorta, ME decreased the vasoconstrictor response to NA and ET-1 and exerted a potent anti-inflammatory and antioxidant effect. Neither RA nor 6-hydroxi-luteolin-O-glucoside, major compounds of this ME, were effective in improving cardiac contractility after IR or attenuating vasoconstriction to NA and ET-1 in aorta segments. CONCLUSION: In conclusion, ME reduces the myocardial damage induced by IR and the contractile response to vasoconstrictors in the aorta. Thus, it may be useful for the treatment of cardiovascular diseases such as myocardial infarction and hypertension.

The Role of 20-HETE, COX, Thromboxane Receptors, and Blood Plasma Antioxidant Status in Vascular Relaxation of Copper-Nanoparticle-Fed WKY Rats.

Recently, the addition of copper nanoparticles (NPs) in a daily diet (6.5 mg/kg) was studied in different animal models as a possible alternative to ionic forms. Male Wistar-Kyoto rats (24-week-old, n = 11) were fed with copper, either in the form of carbonate salt (Cu6.5) or metal-based copper NPs (NP6.5), for 8 weeks. The third group was fed with a half dose of each (NP3.25 + Cu3.25). The thoracic aorta and blood plasma was studied. Supplementation with NP6.5 decreased the Cu (×0.7), Cu/Zn-ratio (×0.6) and catalase (CAT, ×0.7), and increased Zn (×1.2) and superoxide dismutase (SOD, ×1.4). Meanwhile, NP3.25 + Cu3.25 decreased the Cu/Zn-ratio (×0.7), and CAT (×0.7), and increased the daily feed intake (×1.06). Preincubation with either the selective cyclooxygenase (COX)-2 inhibitor, or the non-selective COX-1/2 inhibitor attenuated vasodilation of rat thoracic aorta in the NP6.5 group exclusively. However, an increased vasodilator response was observed in the NP6.5 and NP3.25 + Cu3.25 group of rats after preincubation with an inhibitor of 20-hydroxyeicosatetraenoic acid (20-HETE) formation, and the thromboxane receptor (TP) antagonist. Significant differences were observed between the NP6.5 and NP3.25 + Cu3.25 groups of rats in: dietary intake, acetylcholine-induced vasodilation, and response to COX-inhibitors. Copper NPs in a standard daily dose had more significant effects on the mechanism(s) responsible for the utilization of reactive oxygen species in the blood plasma with the participation of prostanoids derived from COX-2 in the vascular relaxation. Dietary copper NPs in both doses modified vasodilation through the vasoconstrictor 20-HETE and the TP receptors.

Cyperus esculentus L. and Tetracarpidium conophorum Müll. Arg. Supplemented Diet Improved Testosterone Levels, Modulated Ectonucleotidases and Adenosine Deaminase Activities in Platelets from L-NAME-Stressed Rats.

In hypertensive individuals, platelet morphology and function have been discovered to be altered, and this has been linked to the development of vascular disease, including erectile dysfunction (ED). The impact of nutritional supplementation with Cyperus esculentus (tiger nut, TN) and Tetracarpidium conophorum (walnut, WN) on androgen levels, ectonucleotidases, and adenosine deaminase (ADA) activities in platelets from L-NAME (Nω-nitro-L-arginine methyl ester hydrochloride) challenged rats were investigated. We hypothesized that these nuts may show a protective effect on platelets aggregation and possibly enhance the sex hormones, thereby reverting vasoconstriction. Wistar rats (male; 250-300 g; n = 10) were grouped into seven groups as follows: basal diet control group (I); basal diet/L-NAME/Viagra (5 mg/kg/day) as positive control group (II); ED-induced group (basal diet/L-NAME) (III); diet supplemented processed TN (20%)/L-NAME (IV); diet supplemented raw TN (20%)/L-NAME (V); diet supplemented processed WN (20%)/L-NAME (VI); and diet supplemented raw WN (20%)/L-NAME (VII). The rats were given their regular diet for 2 weeks prior to actually receiving L-NAME (40 mg/kg/day) for ten days to induce hypertension. Platelet androgen levels, ectonucleotidases, and ADA were all measured. L-NAME considerably lowers testosterone levels (54.5 ± 2.2; p < 0.05). Supplementing the TN and WN diets revealed improved testosterone levels as compared to the control (306.7 ± 5.7), but luteinizing hormone levels remained unchanged. Compared to control groups, the L-NAME-treated group showed a rise in ATP (127.5%) hydrolysis and ADA (116.7%) activity, and also a decrease in ADP (76%) and AMP (45%) hydrolysis. Both TN and WN supplemented diets resulted in substantial (p < 0.05) reversal effects. Enhanced testosterone levels and modulation of the purinergic system in platelets by TN and WN could be one of the mechanisms by which they aid in vasoconstriction control.

Gynura procumbens ethanol extract improves vascular dysfunction by suppressing inflammation in postmenopausal rats fed a high-fat diet.

CONTEXT: Gynura procumbens (Lour.) Merr. (Asteraceae) has been reported to have various pharmacological activities including anti-inflammatory effects. OBJECTIVE: This study sought to determine whether Gynura procumbens (GP) could improve vascular reactivity by suppressing inflammation in postmenopausal rats fed with five-times heated palm oil (5HPO) diet. MATERIALS AND METHODS: Forty-eight female Sprague-Dawley rats were randomly divided into sham [non-ovariectomized; grouped as control, GP extracts (250 and 500 mg/kg), atorvastatin (ATV, 10 mg/kg)] and postmenopausal (PM) groups [ovariectomized rats fed with 5HPO; grouped as PM, GP extracts (250 and 500 mg/kg) and ATV (10 mg/kg)]. Each group (n = 6) was either supplemented with GP extract or ATV orally once daily for 6 months. RESULTS: In comparison with the untreated PM group, 250 and 500 mg/kg GP supplementation to PM groups reduced the systolic blood pressure (103 ± 2.7, 86 ± 2.4 vs. 156 ± 7.83 mmHg, p < 0.05), intima-media thickness (101.28 ± 3.4, 93.91 ± 2.93 vs. 143.78 ± 3.31 µM), vasoconstriction percentage induced by phenylephrine (102.5%, 88.3%, vs. 51.8%), sICAM-1 (0.49, 0.26 vs. 0.56 pg/mL) and sVCAM-1 (0.39, 0.25 vs. 0.45 pg/mL). GP extract supplementation increased vasorelaxation percentage induced by acetylcholine (78.4% vs. 47.3%) and sodium nitroprusside (84.2% vs. 53.7%), increased changes in plasma nitric oxide level (1.25%, 1.31% vs. 1.9%), and suppressed the elevation of TNF-α (0.39 vs. 1.02 pg/mL), IL-6 (0.43 vs. 0.77 pg/mL) and CRP (0.29 vs. 0.69 ng/mL) in the PM groups. CONCLUSIONS: GP extract might improve vascular dysfunction by suppressing the inflammatory response, consequently preventing blood pressure elevation.

Reversible Cerebral Vasoconstriction Syndrome Following Exposure to Oleoresin Capsicum "Pepper Spray".

OBJECTIVES: To report a case associating the use of Oleoresin Capsicum Pepper Spray (OCPS) during law enforcement training with development of Reversible Cerebral Vasoconstriction Syndrome (RCVS). MATERIALS AND METHODS: RCVS is radiographically characterized by multifocal smooth narrowing of cerebral arteries heralded by clinical manifestations of recurrent thunderclap headaches. 70% of cases with RCVS have a clear precipitating factor and agents commonly implicated were cannabis, selective serotonin reuptake inhibitors, nasal decongestants, cocaine, postpartum state, eclampsia and strenuous physical/sexual activity.1 RESULTS: 24-year-old female police officer with no past medical history who presented with thunderclap headaches after exposure to pepper spray to her face during work training. Neurological examination was unremarkable. CT angiogram (CTA) of the head and neck and subsequent conventional angiogram revealed multifocal mild arterial narrowing of bilateral middle cerebral arteries (MCA), bilateral posterior cerebral arteries (PCA) and left anterior cerebral artery (ACA) concerning for RCVS. Eight weeks later, she had a repeat MRA head and neck demonstrating complete resolution of the previously noted narrowing of her cerebral arteries. CONCLUSIONS: OCPS is widely used in law enforcement training as well as by general population as a self- defense tool. It is generally assumed to be safe, although the consequences of its use can never be predicted with certainty.2 As our case highlights, use of OCPS may be associated with development of RCVS and awareness needs to be raised regarding this rare but serious complication.

Standardized root extract of Withania somnifera and Withanolide A exert moderate vasorelaxant effect in the rat aortic rings by enhancing nitric oxide generation.

ETHNO-PHARMACOLOGICAL RELEVANCE: Withania somnifera (L.) Dunal, commonly known as Ashwagandha, belongs to the family Solanaceae. In Ayurveda, Ashwagandha has been defined as one of the most important herb and is considered to be the best adaptogen. It is also an excellent rejuvenator, a general health tonic and cure for various disorders such as cerebrovascular, insomnia, asthma, ulcers, etc. Steroidal lactones (Withanolides: Withanolide A, Withaferin A, Withanolide D, Withanone, etc) isolated from this plant, possess promising medicinal properties such as anti-inflammatory, immune-stimulatory etc. Standardized root extract of the plant NMITLI-118R (NM) was prepared at CSIR-CIMAP, and was investigated for various biological activities at CSIR-CDRI. Among the notable medicinal properties, NM exhibited excellent neuroprotective activity in the middle cerebral artery occlusion (MCAO) rat model. AIM OF THE STUDY: Endothelial dysfunction is the primary event in the cerebrovascular or cardiovascular disorders, present study was thus undertaken to evaluate vasoprotective potential of NM and its biomarker compound Withanolide A (WA) using rat aortic rings and EA.hy926 endothelial cells. MATERIAL AND METHODS: Transverse aortic rings of 10 weeks old Wistar rats were used to evaluate effect of NM and WA on the vasoreactivity. While, mechanism of NM and WA mediated vasorelaxant was investigated in Ea.hy926 cell line by measuring NO generation, nitrite content, Serine 1177 phosphorylation of eNOS, reduced/oxidized biopterin levels and expression of endothelial nitric oxide synthase (eNOS) mRNA and protein. RESULTS: Fingerprinting of NM using HPLC identified presence of WA in the extract. NM as well as WA exerted moderate vasorelaxant effect in the endothelium intact rat aortic rings which was lesser than acetylcholine (ACh). NM and WA augmented ACh induced relaxation in the rat aortic rings. NM and WA dependent vasorelaxation was blocked by N-nitro-L-arginine methyl ester (L-NAME) or 1H-[1,2,4] oxadiazolo [4,3,-a]quinoxalin-1-one (ODQ), indicating role of NO/cGMP. Further Ea.hy926 cells treated with NM and WA showed accumulation of nitrite content, enhanced NO levels, eNOS expression and eNOS phosphorylation (Serine 1177). CONCLUSION: Altogether NM and WA dependent improvement in the NO availability seems to be mediated by the enhanced eNOS phosphorylation. WA, seems to be one of the active constituent of NM, and presence of other vasoactive substances cannot be ruled out. The data obtained imply that the vasorelaxant property of NM is beneficial for its neuroprotective potential.

COVID-19 Associated Reversible Cerebral Vasoconstriction Syndrome Successfully Treated with Nimodipine and Aspirin.

There have been limited cases linking SARS-CoV-2 infection with the development of reversible cerebral vasoconstriction syndrome (RCVS). We hereby report a rare case of RCVS in the setting of mild SARS-CoV-2 respiratory infection successfully treated with nimodipine and aspirin. SARS-CoV-2 attacks the ACE2-receptors, which are expressed in various body organs including the lungs, kidneys, and blood vessels. Vasoconstriction can result from down-regulation of the ACE2-receptors that can lead to sympathetic hypertonia of the cerebral blood vessel walls and/or over-activation of the renin-angiotensin axis.

Calcitriol Supplementation Ameliorates Microvascular Endothelial Dysfunction in Vitamin D-Deficient Diabetic Rats by Upregulating the Vascular eNOS Protein Expression and Reducing Oxidative Stress.

Diabetes mellitus contributes to macro- and microvascular complications, leading to adverse cardiovascular events. This study examined the effects of vitamin D deficiency on the vascular function and tissue oxidative status in the microcirculation of diabetic rats and to determine whether these effects can be reversed with calcitriol (active vitamin D metabolite) supplementation. Streptozotocin-induced diabetic rats were fed for 10 weeks with control diet (DC) or vitamin D-deficient diet without (DD) or with oral calcitriol supplementation (0.15 µg/kg) in the last four weeks (DDS) (10 rats each group). A nondiabetic rat group that received control diet was also included (NR). After 10 weeks, rats were sacrificed; mesenteric arterial rings with and without endothelium were studied using wire myograph. Western blotting of the mesenteric arterial tissue was performed to determine the protein expression of endothelial nitric oxide synthase (eNOS) enzyme. Antioxidant enzyme superoxide dismutase (SOD) activity and oxidative stress marker malondialdehyde (MDA) levels in the mesenteric arterial tissue were also measured. The DC group had significantly lower acetylcholine-induced relaxation and augmented endothelium-dependent contraction, with reduced eNOS expression, compared to NR rats. In mesenteric arteries of DD, acetylcholine-induced endothelium-dependent and sodium nitroprusside-induced endothelium-independent relaxations were lower than those in DC. Calcitriol supplementation in DDS restored endothelium-dependent relaxation. Mesenteric artery endothelium-dependent contraction of DD was greater than DC; it was not affected by calcitriol supplementation. The eNOS protein expression and SOD activity were significantly lower while MDA levels were greater in DD compared to DC; these effects were not observed in DDS that received calcitriol supplementation. In conclusion, vitamin D deficiency causes eNOS downregulation and oxidative stress, thereby impairing the vascular function and posing an additional risk for microvascular complications in diabetes. Calcitriol supplementation to diabetics with vitamin D deficiency could potentially be useful in the management of or as an adjunct to diabetes-related cardiovascular complications.

Effects of oleuropein on rat's atria and thoracic aorta: a study of antihypertensive mechanisms.

Oleuropein (OLE) is the main bioactive ingredient in the leaves of the olive plant Olea europaea L. (Oleaceae), which has proven beneficial due to the antiinflammatory, antiatherogenic, anticancer, antimicrobial, and antiviral effects. This study aimed to investigate the antihypertensive and vasodilator potential of OLE by analyzing its acute effects on spontaneous atrial contractions and vasomotor responses of the isolated thoracic aorta in rats. We showed that the application of OLE induces negative chronotropic and inotropic effects on the heart. OLE also causes mild aortic vasodilation given that the maximal reduction in tension of intact aortic rings precontracted with phenylephrine was approximately 30%. This vasodilation is likely dependent on the nitric oxide released from the endothelium based on the effect obtained on denuded and phenylephrine precontracted aortic rings and responses reordered following vasoconstriction induced by high concentrations of K+ and heparin. Our findings provide a basis for further testing of OLE cardiovascular effects, which may lead to subsequent clinical research for its application in the treatment of hypertension and heart disease.

Endothelium-Independent Relaxation of Vascular Smooth Muscle Induced by Persimmon-Derived Polyphenol Phytocomplex in Rats.

The vasorelaxant effect of polyphenols is well known, and the mortality rate due to coronary artery disease is low in people who consume polyphenol-containing foods. We aimed to elucidate the mechanism by which polyphenols derived from persimmon juice (PJ) and persimmon leaves (PLs) induce vasorelaxation and suppress vasocontraction in the superior mesenteric arteries isolated from male Sprague Dawley rats. Vasocontraction was induced with 1 µM phenylephrine, and polyphenol-induced vasorelaxation was expressed as a percentage of the previous tone induced by phenylephrine. PJ powder (100 mg/L) induced higher levels of vasorelaxation (mean ± standard error of the mean, 88.6% ± 4.4%) than PLs powder (1 g/L; 72.0% ± 10.8%). Nitric oxide pathway inhibitors (NG-nitro-L-arginine methyl ester + carboxy-PTIO) did not affect persimmon-derived polyphenol-induced vasorelaxation, whereas potassium chloride, tetraethylammonium, and potassium-channel inhibitors did. Vasorelaxation was endothelium independent with both extracts. Phenylephrine-induced vasocontraction was suppressed by pretreatment with PJ and PLs powder, even when inositol triphosphate-mediated Ca2+ release and extracellular Ca2+ influx were inhibited. These results suggest that persimmon-derived polyphenol phytocomplex cause vasorelaxation and inhibit vasocontraction through hyperpolarization of smooth muscle cells. Persimmon-derived polyphenols may be able to prevent cardiovascular diseases caused by abnormal contraction of blood vessels.

Interactive Effects of Omega-3 Polyunsaturated Fatty Acids and Secondhand Smoke in Mice and Human Subjects.

Active smoking and secondhand smoke (SHS) exposure increase the risk of cardiovascular morbidity and mortality. Active smoking is associated with reduced levels of omega-3 polyunsaturated fatty acids (n-3 PUFA) and studies show that n-3 PUFA supplementation can improve smoking-induced vascular dysfunction. However, the relationship between n-3 PUFA and SHS exposure has not been studied. Fat-1 transgenic mice, which convert n-6 to n-3 PUFA, were fed diets with n-3 PUFA or without (n-6 PUFA diet), exposed to air or SHS for 4 weeks, and vasoreactivity, antioxidant indices, and omega-3 index (percent eicosapentaenoic + docosahexaenoic acids in RBC) measured. Compared to air-exposed mice, SHS-enhanced aortic constriction in mice fed the n-6 PUFA diet (omega-3 index, 5.9 ± 0.2%; mean ± SE), but not in mice fed the n-3 PUFA diet (omega-3 index, 7.8 ± 0.6%). SHS also significantly induced mRNA expression of cytochrome P4501A1, NADPH:quinone oxidoreductase, heme oxygenase-1, and angiotensinogen in adipose tissue, and increased antioxidant capacity only in mice on the n-6 PUFA diet. Notably, SHS reduced the omega-3 index by 1.0 percentage point (p = 0.003), compared to air-exposed mice irrespective of diet. Additionally, we recruited human nonsmokers (NS) with and without SHS exposure (n = 40) 19-40 years old and measured the omega-3 index and antioxidant capacity. In human subjects SHS exposure was associated with a significantly lower omega-3 index (NS, 4.4 ± 1.1%; NS + SHS, 3.2 ± 1.0%; mean ± SD, p = 0.002) and higher antioxidant capacity (p < 0.001) than unexposed NS. Thus, SHS exposure is associated with lower levels of n-3 PUFA in mice and humans; however, an omega-3 index of ~ 8% in mice has vasoprotective and antioxidant properties.

Aldosterone Induces Vasoconstriction in Individuals with Type 2 Diabetes: Effect of Acute Antioxidant Administration.

CONTEXT: Individuals with type 2 diabetes have an increased risk of endothelial dysfunction and cardiovascular disease. Plasma aldosterone could contribute by reactive oxygen species-dependent mechanisms by inducing a shift in the balance between a vasoconstrictor and vasodilator response to aldosterone. OBJECTIVE: We aimed to investigate the acute vascular effects of aldosterone in individuals with type 2 diabetes compared with healthy controls and if infusion of an antioxidant (n-acetylcysteine [NAC]) would alter the vascular response. METHODS: In a case-control design, 12 participants with type 2 diabetes and 14 healthy controls, recruited from the general community, were studied. Leg hemodynamics were measured before and during aldosterone infusion (0.2 and 5 ng min-1 [L leg volume]-1) for 10 minutes into the femoral artery with and without coinfusion of NAC (125 mg kg-1 hour-1 followed by 25 mg kg-1 hour-1). Leg blood flow and arterial blood pressure was measured, and femoral arterial and venous blood samples were collected. RESULTS: Compared with the control group, leg blood flow and vascular conductance decreased during infusion of aldosterone at the high dose in individuals with type 2 diabetes, whereas coinfusion of NAC attenuated this response. Plasma aldosterone increased in both groups during aldosterone infusion and there was no difference between groups at baseline or during the infusions. CONCLUSION: These results suggests that type 2 diabetes is associated with a vasoconstrictor response to physiological levels of infused aldosterone and that the antioxidant NAC diminishes this response.

The composition and vascular/antioxidant properties of Taraxacum officinale flower water syrup in a normal-fat diet using an obese rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: Taraxacum officinale (L.), commonly called dandelion has been used for centuries as a natural medicine to treat inflammatory diseases including some metabolic alterations associated with obesity. AIM OF THE STUDY: Based on animal experiments this study aims to explore the potential mechanisms of action of T. officinale flower water syrup (TOFS) together with a normal-fat diet in the intervention of obesity. MATERIALS AND METHODS: Obese male albino-Wistar rats (n = 8) at 25 weeks of age were fed with a normal-fat diet with or without added 27.82% TOFS (w/w) for 4 weeks. The reactivity of thoracic aorta and antioxidant capacity were studied. RESULTS: TOFS delivered daily 926.8 µg of L-chicoric acid, 20.19 µg of luteolin and 3.379 ‬g of sucrose. TOFS showed beneficial effects by regulating blood lipids (HDL, x1.11-fold increase), thereby lowering the risk factors for atherosclerosis (TC/HDL, x0.90-fold). The antioxidant status was improved via an increase in plasma superoxide radical scavenging (SOD, x1.6-fold) and a decrease in lipid peroxidation (MDA, x0.81-fold). Moreover, the following were decreased: Cu (x0.53-fold), Zn (x0.72-fold) and the Cu/Zn molar ratio (x0.60-fold). A marker for liver damage/disease was beneficially decreased (ALP, x0.87-fold). TOFS modulated in a significant way COX-depended relaxation to ACh (p = 0.05) but not to CORM-2 (p = 0.1651) in isolated thoracic arteries, by decreased participation of vasoconstrictor prostanoids. The vascular contraction to prostaglandin F2α was also decreased (x0.62-fold). We observed no change in the feed intake, body weight, organ-to-body weight ratio, blood glucose, CAT, FRAP, AST, ALT, TBARS/carbonyls (in heart, liver, kidneys, spleen) and carbonyls (in blood plasma, thoracic arteries); as well as F2-isoprostanes in urine. Vascular response to the vasodilators ACh, SNP, A23187, CORM-2, pinacidil, NS-1619 and to the vasoconstrictors NA, U-46619, ET-1 as well as hyperpolarizing mechanism(s) were not modified. CONCLUSIONS: TOFS possesses beneficial properties by regulating prostanoids and antioxidant status.

TMEM16A-encoded anoctamin 1 inhibition contributes to chrysin-induced coronary relaxation.

BACKGROUND: Chrysin, a natural flavonoid available in honey, propolis and medicinal plants, has been shown to be vasorelaxant in some vascular beds. Proper intake of an alimental vasodilator as a food additive may be a promising strategy for prevention and treatment of coronary spasmodic disorders. PURPOSE: TMEM16A-encoded anoctamin 1 (ANO1), a Ca2+ activated Cl- channel (CaCC), plays an important role in the modulation of vascular tone. We tested the possibility that inhibition of CaCCs contributes to chrysin-induced coronary arterial relaxation. METHODS: The vascular tone of the rat coronary artery (RCA) was recorded with a wire myograph. CaCC currents were assessed using whole-cell patch clamp in arterial smooth muscle cell (ASMC) freshly isolated from RCAs. An inhibitor study was performed to explore the mechanisms underlying the vasomotor and electrophysiological effects of chrysin. RESULTS: Pre-incubation with chrysin depressed the contractions elicited by thromboxane A2 analog U46619, vasopressin (VP), depolarization and extracellular Ca2+ elevation/depolarization without significant preference among these vasoconstrictors. Besides, chrysin inhibited both intracellular Ca2+ release-dependent and extracellular Ca2+ influx-dependent components of contractions induced by U46619 or VP. In RCAs pre-contracted with U46619, VP or KCl, chrysin elicited concentration-dependent relaxations, which were weakened by Cl- -deprivation. The electrophysiological study showed that chrysin reduced ANO1-antibody-sensitive CaCC currents and depressed CaCC increments induced by U46619. Inhibitor study showed that both the vasorelaxation and the CaCC current reduction induced by chrysin were attenuated by blocking CaCCs and inhibiting cAMP/PKA and NO/PKG pathways. CONCLUSION: The present findings indicate that inhibition of RCA ASMC CaCC currents, which may be consequential following intracellular Ca2+ availability reduction and activation of cAMP/PKA and NO/cGMP signaling pathways, contributes to chrysin-induced RCA relaxation.

Preventive treatment with ginsenoside Rb1 ameliorates monocrotaline-induced pulmonary arterial hypertension in rats and involves store-operated calcium entry inhibition.

CONTEXT: Ginsenoside Rb1, the main active ingredient of ginseng, exhibits ex vivo depression of store-operated calcium entry (SOCE) and related vasoconstriction in pulmonary arteries derived from pulmonary hypertension (PH) rats. However, the in vivo effects of ginsenoside Rb1 on PH remain unclear. OBJECTIVE: This study explored the possibility of using ginsenoside Rb1 as an in vivo preventive medication for type I PH, i.e., pulmonary arterial hypertension (PAH), and potential mechanisms involving SOCE. MATERIALS AND METHODS: Male Sprague-Dawley rats (170-180 g) were randomly divided into Control, MCT, and MCT + Rb1 groups (n = 20). Control rats received only saline injection. Rats in the MCT + Rb1 and MCT groups were intraperitoneally administered single doses of 50 mg/kg monocrotaline (MCT) combined with 30 mg/kg/day ginsenoside Rb1 or equivalent volumes of saline for 21 consecutive days. Subsequently, comprehensive parameters related to SOCE, vascular tone, histological changes and hemodynamics were measured. RESULTS: Ginsenoside Rb1 reduced MCT-induced STIM1, TRPC1, and TRPC4 expression by 35.00, 31.96, and 32.24%, respectively, at the protein level. SOCE-related calcium entry and pulmonary artery contraction decreased by 162.6 nM and 71.72%. The mean pulmonary artery pressure, right ventricle systolic pressure, and right ventricular mass index decreased by 19.5 mmHg, 21.6 mmHg, and 39.50%. The wall thickness/radius ratios decreased by 14.67 and 17.65%, and the lumen area/total area ratios increased by 18.55 and 15.60% in intrapulmonary vessels with 51-100 and 101-150 µm o.d. CONCLUSION: Ginsenoside Rb1, a promising candidate for PH prevention, inhibited SOCE and related pulmonary vasoconstriction, and relieved MCT-induced PAH in rats.

Sulforaphane improves vascular reactivity in mouse and human arteries after "preeclamptic-like" injury.

INTRODUCTION: The widespread maternal endothelial dysfunction that underlies the manifestations of preeclampsia is thought to arise from excessive placental production of antiangiogenic factors and enhanced oxidative stress. Therefore, we assessed whether the natural antioxidant sulforaphane could improve vascular function. METHODS: Cell viability of human umbilical vein endothelial cells (HUVECs) was assessed after 24 or 48 h in normoxia (20% O2) or hypoxia (1% O2) with or without sulforaphane. To model vascular dysfunction associated with preeclampsia, mouse mesenteric arteries were incubated in trophoblast conditioned media (TCM), and human omental arteries incubated in preeclamptic explant media (PEM) with or without sulforaphane. Both media are rich in antiangiogenic compounds associated with preeclampsia. TCM was generated from primary cytotrophoblast cells from term placentae of normotensive, while PEM was generated from explants from preeclamptic women. Reactivity was assessed by wire myography. sulforaphane's actions as a vasodilator were also investigated. RESULTS: Under conditions of hypoxia, sulforaphane improved HUVEC viability. In mouse mesenteric arteries, sulforaphane reduced contraction evoked by potassium (p < 0.001), phenylephrine and endothelin 1 (all p < 0.001). Sulforaphane also inhibited Ca2+-induced contraction (p = 0.014). Sulforaphane prevented TCM-induced augmentation of phenylephrine and angiotensin II-mediated contraction of mouse mesenteric arteries. In human omental arteries, sulforaphane induced vasodilation (p < 0.001), and prevented PEM-induced endothelial dysfunction by restoring arterial sensitivity to the endothelium-dependent vasodilator bradykinin (p = 0.008). DISCUSSION: Sulforaphane causes relaxation in arteries and protects against arterial dysfunction induced by placental-derived antiangiogenic factors, which are known to contribute to the preeclampsia.

Echinacoside prevents hypoxic pulmonary hypertension by regulating the pulmonary artery function.

Hypoxic pulmonary hypertension (HPH) is a progressive and irreversible disease that reduces survival. Echinacoside is a phenylethanoid glycoside from Tibetan herbs known for its vasorelaxant effect and for inhibiting the proliferation of rat pulmonary arterial smooth muscle cells. This study aimed to investigate the effect of echinacoside on HPH. Sprague Dawley rats were housed in a hypobaric hypoxia chamber (4500 m) for 28 days to obtain the HPH model. Echinacoside (3.75, 7.5, 15, 30 and 40 mg/kg) was administered by intraperitoneal injection from the 1st to the 28th day. The mean pulmonary artery pressure (mPAP), right ventricular hypertrophy index, hemoglobin, hematocrit, red blood cell concentration and morphological change of pulmonary arteries were evaluated. Vascular perfusion assay was used to assess the pulmonary artery function. Echinacoside reduced mPAP, hemoglobin, hematocrit, right ventricular hypertrophy index and mean wall thickness% of pulmonary arteries in HPH rats. It significantly increased maximum vasoconstriction percentage of pulmonary arteries induced by noradrenaline in a dose-dependent manner. In addition, it improved the responsiveness of pulmonary arteries to acetylcholine and sodium nitroprusside. Therefore, Echinacoside might be an effective treatment against HPH, since it regulated pulmonary artery endothelium and smooth muscle layer function and improved the remodeling of pulmonary artery.

Effects of a dammarane-type saponin, ginsenoside Rd, in nicotine-induced vascular endothelial injury.

BACKGROUND: Panax notoginseng (Burk.) F.H. Chen is a traditional medicinal plant widely used to prevent and treat cardiovascular diseases. Ginsenoside Rd (GRd) is a major bioactive component of P. notoginseng, but specific effects on cardiovascular disease-related pathogenic processes are rarely studied, especially vascular endothelial injury. PURPOSE: This study investigated the potential protective efficacy of GRd against nicotine-induced vascular endothelial cell injury, disruption of vascular nitric oxide (NO) signaling, aberrant endothelium-monocyte adhesion, platelet aggregation, and vasoconstriction. STUDY DESIGN/METHODS: Vascular endothelial injury and functional disruption were investigated in cultured human umbilical vein endothelial cells (HUVECs) by biochemical assays for nitric oxide (NO) and angiotensin II (Ang II), immunofluorescence (IF) and western blotting for expression analyses of apoptosis- related proteins, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), Ang II type receptor 1 (AGTR1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappa B (NF-κB). In addition, vascular protection by GRd was examined in nicotine-administered Sprague-Dawley (SD) rats by serum NO and Ang II assays, and by hematoxylin-eosin (HE) and immunostaining of aorta. We also examined effects of GRd on monocyte (THP-1 cells) adhesion assays, adenosine diphosphate (ADP)-induced platelet aggregation, and phenylephrine (PE)-induced vasoconstriction of isolated rat aortic rings. RESULTS: In HUVECs, nicotine significantly suppressed NO production, enhanced Ang II production, downregulated eNOS expression, and upregulated expression levels of AGTR1, TLR4, MyD88, NF-κB, iNOS, Bax/Bcl-2 ratio, cleaved caspase-3, and cytochrome c (cyt c). All of these changes were significantly reversed by GRd. In rats, oral GRd reversed the reduction NO and enhanced Ang II production in serum induced by nicotine administration, and HE staining revealed protection of aortic endothelial cells. In addition, GRd reversed nicotine-mediated enhancement of HUVECs-monocyte adhesion, inhibited ADP-induced platelet aggregation and PE-induced vasoconstriction. CONCLUSION: GRd may prevent nicotine-induced cardiovascular diseases by preserving normal vascular endothelial NO signaling, suppressing platelet aggregation and vasoconstriction, and by preventing endothelial cell-monocyte adhesion.