Mesenteric Vascular Reactivity Research Articles

Cardioprotective Effects of Solidago microglossa DC. in Nicotine-Treated Hypertensive Rats.

Solidago microglossa DC. (Asteraceae), "arnica brasileira," is a Brazilian species popularly used to treat hypertension or renal ailments. This study investigated the cardioprotective effects of standardized S. microglossa extract (EESM) in nicotine-treated spontaneously hypertensive rats (SHRs). Moreover, the molecular mechanisms involved in the cardiovascular effects were also investigated. The acute toxicity was evaluated in female Wistar rats. Afterwards, six-month-old male spontaneously hypertensive rats received the EESM (14, 28, and 56 mg/kg), hydrochlorothiazide (25 mg/kg), and vehicle (filtered water; 0.1 mL/100 g) once daily for 28 days. All treatments were associated with 1.8 mg/kg of nicotine. At the end of the experimental period, the renal function, electrocardiographic profile, blood pressure, ventricular function, biochemical parameter, and mesenteric vascular bed reactivity were evaluated. Relative organ weights and cardiac morphometry were also investigated. Nicotine treatment in 6-month-old SHRs induced a significant reduction in renal function, with reduced urinary volume and lower renal elimination of sodium and creatinine. In addition, serum markers of the redox state and blood pressure levels remained significantly elevated, contributing to changes in vascular reactivity and left ventricular hypertrophy associated with reduced ventricular function. After 28 days of treatment, we found that the highest dose of EESM could mitigate all renal and cardiovascular changes developed by the nicotine-treated hypertensive rats. This study presented EESM as a possible cardioprotective drug that prevents cardiovascular dysfunctions in nicotine-treated hypertensive rats. Our data suggest EESM as a potential adjuvant therapy when cardioprotective effects are required.

Effects of Δ9-Tetrahydrocannabinol and the Aminoalkylindole K2/Spice Constituent JWH-073 on Cardiac Tissue and Mesenteric Vascular Reactivity.

Background: Although use of Cannabis sativa is not associated with serious adverse effects, recreational use of aminoalkylindole (AAI) cannabinoid receptor agonists found in K2/Spice herbal blends has been reported to cause adverse cardiovascular events, including angina, arrhythmia, changes in blood pressure, ischemic stroke, and myocardial infarction. Δ9-Tetrahydrocannabinol (Δ9-THC) is the primary CB1 agonist found in cannabis and JWH-073 is one of the AAI CB1 agonists found in K2/Spice brands sold to the public. Methods: This study used in vitro, in vivo, and ex vivo approaches to investigate potential differences on cardiac tissue and vascular effects betweenJWH-073 and Δ9-THC. Male C57BL/6 mice were treated with JWH-073 or Δ9-THC and cardiac injury was assessed by histology. Effects of JWH-073 and Δ9-THC on H9C2 cell viability and ex vivo mesenteric vascular reactivity were also determined. Results: JWH-073 or Δ9-THC induced typical cannabinoid effects of antinociception and hypothermia but did not promote death of cardiac myocytes. No differences in cell viability were observed in cultured H9C2 cardiac myocytes after 24 h of treatment. In isolated mesenteric arteries from drug-naive animals, JWH-073 produced significantly greater maximal relaxation (96%±2% vs. 73%±5%, p<0.05) and significantly greater inhibition of phenylephrine-mediated maximal contraction (Control 174%±11%KMAX) compared with Δ9-THC (50%±17% vs. 119%±16%KMAX, p<0.05). Discussion: These findings suggest that neither cannabinoid at the concentrations/dose studied caused cardiac cell death, but JWH-073 has the potential for greater vascular adverse events than Δ9-THC through an increased vasodilatory effect.

A New Approach for the Development of Multiple Cardiovascular Risk Factors in Two Rat Models of Hypertension.

Cardiovascular disease (CVD) is the leading cause of death among non-communicable diseases. There is a lack of valid animal models that mimic associations among multiple cardiovascular risk factors in humans. The present study developed an animal model that uses multiple cardiovascular risk factors—namely, hypertension, hypothyroidism, and a high-fat diet (HFD). Two models of hypertension were used: renovascular hypertension (two-kidney, one clip [2K1C]) and spontaneously hypertensive rats (SHRs). The naive group was composed of normotensive rats. Twelve weeks after surgery to induce renovascular hypertension, rats in the 2K1C and SHR groups underwent thyroidectomy. The HFD was then implemented for 6 weeks. Renal function, serum redox status, biochemical CVD markers, electrocardiographic profile, blood pressure, mesenteric vascular bed reactivity, histopathology, and morphometry were investigated. Both experimental models induced dyslipidemia, renal function impairment, and hepatic steatosis, accompanied by higher levels of different inflammatory markers and serum oxidative stress. These alterations contributed to end-organ damage in all hypertensive rats. Our findings corroborate a viable alternative model that involves multiple cardiovascular risk factors and resembles conditions that are seen in humans. Both models mimicked CVD, but our data show that SHRs exhibit more significant pathophysiological changes.

Conditional deletion of the glucocorticoid receptor in vascular smooth muscle disrupts the circadian rhythm of vascular reactivity and reduces blood pressure

Glucocorticoids synchronise peripheral clocks with the master clock in the suprachiasmatic nucleus in response to the ambient light cycle. In humans and mice, arrhythmic glucocorticoids induce non‐dipping blood pressure and vascular dysfunction. The mechanisms of this are poorly understood. We hypothesize that arrhythmic activation of the glucocorticoid receptor attenuates the circadian clock signalling in the vasculature leading to changes in blood pressure. To test this hypothesis, we assessed vascular function and blood pressure rhythms in control mice and mice with smooth muscle specific deletion of the glucocorticoid receptor (SMGRKO).Renal and mesenteric arteries were isolated at 7am (ZT0; lights on) and 7pm (ZT12; lights off), mounted on a wire myograph and the responses to increasing doses of phenylephrine or sodium nitroprusside (SNP) assessed. In wild‐type mice, the sensitivity of the renal artery to phenylephrine‐mediated contraction was greater at ZT12 than at ZT0, by comparing the half maximal effective concentration of each group, (logEC50: 7.54±0.26 versus 7.29±0.17 respectively; p=0.04). The sensitivity to SNP‐mediated relaxation was also greater when measured at ZT12 compared to ZT0 (7.64±0.3 versus 7.09±0.5; p=0.03). Similar responses were also detected in the mesenteric arteries. In SMGRKO mice, the temporal differences in renal and mesenteric artery vascular reactivity were absent. We used radiotelemetry to assess the effect of this altered rhythm of vascular reactivity on blood pressure. SMGRKO had significantly lower systolic blood pressure throughout the 24h cycle compared to wild‐type littermates, both when lights were off (107.9 ± 22.13 versus 136.3 ± 17.17 mmHg respectively; p=0.015) and during the lights on period (99.6 ± 13.16 versus 118 ± 15.9 mmHg; p=0.014). Blood pressure rhythmicity was not altered in SMGRKO mice.These data show that the glucocorticoid receptor signalling in vascular smooth muscle contributes both to the diurnal variation of vascular reactivity and to blood pressure, but loss of the receptor does not affect blood pressure rhythm. Whether glucocorticoid receptor deletion in smooth muscle protects against non‐dipping blood pressure induced by glucocorticoids needs further investigation.

The effect of TNF-α inhibitor treatment on microRNAs and endothelial function in collagen induced arthritis

Chronic inflammation causes dysregulated expression of microRNAs. Aberrant microRNA expression is associated with endothelial dysfunction. In this study we determined whether TNF-α inhibition impacted the expression of miRNA-146a-5p and miRNA-155-5p, and whether changes in the expression of these miRNAs were related to inflammation-induced changes in endothelial function in collagen-induced arthritis (CIA). Sixty-four Sprague-Dawley rats were divided into control (n = 24), CIA (n = 24) and CIA+etanercept (n = 16) groups. CIA and CIA+etanercept groups were immunized with bovine type-II collagen, emulsified in incomplete Freund’s adjuvant. Upon signs of arthritis, the CIA+etanercept group received 10mg/kg of etanercept intraperitoneally, every three days. After six weeks of treatment, mesenteric artery vascular reactivity was assessed using wire-myography. Serum concentrations of TNF-α, C-reactive protein, interleukin-6, vascular adhesion molecule-1 (VCAM-1) and pentraxin-3 (PTX-3) were measured by ELISA. Relative expression of circulating miRNA-146a-5p and miRNA-155-5p were determined using RT-qPCR. Compared to controls, circulating miRNA-155-5p, VCAM-1 and PTX-3 concentrations were increased, and vessel relaxation was impaired in the CIA (all p<0.05), but not in the CIA+etanercept (all p<0.05) groups. The CIA group had greater miRNA-146a-5p expression compared to the CIA+etanercept group (p = 0.005). Independent of blood pressure, miRNA-146a-5p expression was associated with increased PTX-3 concentrations (p = 0.03), while miRNA-155-5p expression was associated with impaired vessel relaxation (p = 0.01). In conclusion, blocking circulating TNF-α impacted systemic inflammation-induced increased expression of miRNA-146a-5p and miRNA-155-5p, which were associated with endothelial inflammation and impaired endothelial dependent vasorelaxation, respectively.

Cardioprotective effects of Talinum paniculatum (Jacq.) Gaertn. in doxorubicin-induced cardiotoxicity in hypertensive rats

Ethnopharmacological relevanceTalinum paniculatum (Jacq.) Gaertn. (Talinaceae) is a medicinal species that is widely distributed throughout Brazil. Popularly known as “major-gomes,” the species is used in folk medicine for the treatment of cardiovascular disorders. Aim of the studyTo evaluate the effect of an ethanolic extract of T. paniculatum (EETP) in rats with renovascular hypertension and heart failure and determine its chemical composition. Materials and methodsFirst, EETP was obtained, and its chemical profile was analyzed by LC-DAD-MS. The acute toxicity was evaluated in female Wistar rats. The model of renovascular hypertension was established in male Wistar rats by combining the Goldblatt 2K1C method and intraperitoneal doxorubicin administration for 6 weeks. The animals were then treated daily with EETP (30, 100, and 300 mg/kg) or metoprolol (25 mg/kg) by gavage for 28 days. The negative control group was treated with vehicle (filtered water). The sham group consisted of animals that were not subjected to 2K1C or cardiotoxicity and were treated with vehicle. Renal function was evaluated on days 1, 14, and 28. At the end of treatment, the electrocardiographic profile, blood pressure, and mesenteric vascular reactivity were investigated. Serum urea, creatinine, angiotensin converting enzyme, nitrotyrosine, malondialdehyde, nitrite, aldosterone, and sodium and potassium levels were measured. The heart, aorta artery, liver, and right kidney were collected, weighed, and processed for histopathological analysis. Cardiac chambers also underwent morphometric analysis. ResultsNo signs of toxicity were observed in female Wistar rats. Thirty-two compounds were annotated from EETP, including flavonoids, chlorogenic acids, and saponins. EETP treatment resulted in a significant cardiorenal-protective response, normalizing electrocardiographic and hemodynamic alterations, and preventing ventricle remodeling. These effects were associated with serum antioxidant activity and angiotensin-converting enzyme (ACE) inhibition. ConclusionThe present study demonstrated that EETP may exert cardioprotective effects through serum antioxidant activity and ACE inhibition, preventing alterations of hemodynamic and endothelial function, and reducing damage to cardiac structure. Thus, EETP, especially at the 100 and 300 mg/kg doses, may be useful for preventing doxorubicin-induced cardiotoxicity in hypertensive patients.

Ethnopharmacological investigation of the cardiovascular effects of the ethanol-soluble fraction of Aloysia polystachya (Griseb.) Moldenke leaves in spontaneously hypertensive rats

Ethnopharmacological relevanceAloysia polystachya (Griseb) Moldenke (Verbenaceae), popularly known as “burrito”, is a South American species widely prescribed by local Brazilian healers for the treatment of cardiovascular diseases. However, its antihypertensive and cardioprotective effects are still unknown. AimTo evaluate the role of the ethanol-soluble fraction of A. polystachya leaves (ESAP) against hypertension in spontaneously hypertensive rats (SHRs), as well as its safety, morphoanatomical and phytochemical aspects. Materials and methodsFirst, the leaves and stems of A. polystachya were analyzed by optical and scanning electron microscopy in order to provide anatomical data for quality control. Then, ESAP was obtained and its chemical profile was analyzed by LC-DAD-MS. In addition, the cytotoxic and acute toxicity potential of ESAP were evaluated in six cell lines and in female Wistar rats, respectively. Next, female spontaneously hypertensive rats (SHRs) received ESAP (30, 100, 300 mg/kg), hydrochlorothiazide (25 mg/kg), or vehicle once daily for 28 days. Weekly kidney function was monitored by analyzing urinary parameters. At the end of the 28-day treatment, the electrocardiographic profile, blood pressure, and renal and mesenteric vascular reactivity were evaluated. Relative organ (heart, kidney, and liver) weights and biochemical parameters were also evaluated. Finally, the heart, kidneys, and aorta were collected for determination of the tissue redox state, cardiac morphometry, and histopathological analysis. ResultsThe chemical profile of ESAP was composed by organic acids, a nucleoside, methoxylated flavones and glycosylated compounds including phenolic acids, phenylpropanoids, iridoids and monoterpenes. No signs of toxicity were observed in all cell's lines nor in female Wistar rats submitted to this trial. All SHRs from the negative control group presented a reduction in renal function, alterations in the renal and mesenteric vascular reactivity, and electrocardiographic and morphometric changes typical of ventricular hypertrophy. Oral prolonged ESAP-administration in SHRs was able to reverse renal, electrocardiographic and hemodynamic changes induced by hypertension. Moreover, ESAP-treatment was able to modulate the vascular and renal arterial reactivity and tissue redox state. The aforementioned data were accompanied by reduction of cardiac hypertrophy. ConclusionIn this study, we present important anatomical and phytochemical data that contributed to the correct identification and quality control of A. polystachya. In addition, we have shown that ESAP is safe after acute administration and present significant cardioprotective effects (at 30, 100, and 300 mg/kg doses) in SHRs after prolonged treatment.

Lead and mercury 28 day exposure at small concentrations reduces smooth muscle relaxation by decreasing cGMP

Cardiovascular diseases are among the main causes of mortality in the world. There is evidence of cardiovascular harm after exposure to low lead or mercury concentrations, but the effects of chronic exposure to the association of low doses of these toxic metals are still unknown. This work evaluated after 4 weeks, the association effects of low concentrations of lead and mercury on blood pressure and vascular resistance reactivity. Wistar rats were exposed for 28 days to lead acetate (1st dose of 4 μg/100 g and subsequent doses of 0.05 μg /100 g/day to cover daily losses) and mercury chloride (1st dose of 2.17 μg/kg and subsequent doses of 0.03 μg/kg/ day to cover daily losses) and the control group received saline, i.m. Results showed that treatment increased blood pressure and induced left ventricular hypertrophy. The mesenteric vascular reactivity to phenylephrine and the endothelium-dependent vasodilator response assessed by acetylcholine did not change. Additionally, reduced involvement of vasoconstrictor prostanoids derived from cyclooxygenase was observed in the PbHg group. By other regulatory routes, such as potassium channels, the vessel showed a greater participation of BKCa channels, and a reduction in the participation of Kv channels and SKCa channels. The endothelium-independent smooth muscle relaxation was significantly impaired by reducing cGMP, possibly through the hyperstimulation of Phosphodiesterase-5 (PDE5). Our results suggested that exposure to low doses of lead and mercury triggers this compensatory mechanism, in response to the augment of arterial pressure.

Chronic Low-Level Lead Exposure Increases Mesenteric Vascular Reactivity: Role of Cyclooxygenase-2-Derived Prostanoids.

Lead (Pb) exposure causes hazardous effects as hypertension and other cardiovascular diseases. We evaluated whether chronic Pb exposure alters the peripheral vascular resistance measuring the vascular reactivity of mesenteric resistance arteries in rats to identify the underlying mechanisms that are associated to the development of Pb-induced hypertension. Mesenteric resistance arteries from lead-treated and untreated Wistar rats (1st dose: 10 μg/100 g; subsequent doses: 0.125 μg/100 g, intramuscular, 30 days) were used. Contractile responses to phenylephrine increased, while acetylcholine and sodium nitroprusside-induced relaxation was not affected by lead treatment. Endothelium removal and inhibition of NO synthase by L-NAME similarly enhanced the response to phenylephrine in untreated and lead-treated rats. The antioxidants apocynin and superoxide dismutase (SOD) did not affect vasoconstriction in either group. The vascular expression of cyclooxygenase-2 (COX-2) protein increased after lead exposure. The respective non-specific or specific COX-2 inhibitors indomethacin and NS398 reduced more strongly the response to phenylephrine in treated rats. Antagonists of EP1 (SC19220), TP (SQ29548), IP (CAY10441) and angiotensin II type 1 (losartan) receptors reduced vasoconstriction only in treated rats. These conclusions present further evidence that lead, even in small concentration, produces cardiovascular hazards being an environmental contaminant that account for lead-induced hypertension.

Differential Mesenteric Venous and Arterial Vascular Reactivity to Adenosine between Rats, Dogs, Mini‐pigs, and Human

It is well established that adenosine induces arterial vasodilation in various vascular beds. However, its effect on the venous circulation is still largely unknown. The splanchnic system receives approximately 25% of cardiac output (CO) and contains approximately 20% of total blood volume. Mesenteric (part of splanchnic system, o. d. 150–250 μm) arteries (MA) and their adjacent veins (MV) from rats, dogs, mini‐pigs and humans were isolated and mounted on a myograph (DMT Technology, USA). Vessels were preconstricted with 1 μM phenylephrine (PE) for arteries and prostaglandin F2α (PGF2α) for veins. Cumulative concentrations of 5’‐N‐Ethylcarboxamidoadenosine (NECA, 10−11 – 10−5 M), a non‐specific adenosine agonist, were applied and evaluated. Tension development was normalized to the tension induced by PE/PGF2α as %. NECA induced a concentration dependent arterial vasodilation in all 3 animals and human MA (Fig. 1). The effects were very similar in all 3 animals (maximum of 91.09±10.94% to 93.88±1.93%), however human responses were less pronounced (maximum of 59.14±4.61%). Interestingly, veins from all species responded to NECA very differently (Fig. 2). MVs from rats were the only vessels that constricted strongly in response to NECA (182.94±17.52% of pre‐constriction), which has not been previously reported (Figs. 2– 3). NECA induced vasodilation in MV from the other species varied. NECA induced vasodilation in MV from dogs were similar to MA at high concentrations (Fig. 6, 10−8 M and above). However, MV from mini‐pig (Fig. 5) and human (Fig. 6) responses were minimal (Fig. 2, maximum of 24.56±14.67% in mini‐pig and 33.54±9.61% relaxation in human) compared to 92.93±2.26% relaxation in dogs. In conclusion, although mesenteric arterial vascular reactivity responds similarly to adenosine among species, mesenteric venous vascular reactivity responses varied greatly to adenosine among species. MVs from rats were the only vessel constricted strongly in response to NECA. Caution is advised when choosing animal models for studying vascular reactivity.Figure 1Figure 2Figure 3Figure 4Figure 5Figure 6

Myeloid mineralocorticoid receptor activation alters metabolism in HFD‐salt fed mice

Context and ObjectivesIn obese mice and patients, mineralocorticoid receptor (MR) activation has deleterious consequences on metabolic and cardiovascular parameters. In mice, adipose tissue MR triggers mitochondrial and vascular dysfunction. Adipocyte MR activation induces metabolic and vascular dysfunction in a context of obesity, however, obese adipose tissue is also infiltrated with macrophages, which are capable of expressing MR. Thus, we hypothesised that macrophage MR could also be responsible for metabolic and cardiovascular complications in high‐fat high‐salt diet‐fed mice.MethodsWe fed myeloid cell‐specific MR knock‐out male and female mice (My‐MRKO) with a 6‐week high fat – high salt diet (60% kcal from fat, 1.2% salt in drinking water) and studied weight gain, whole body and specific organs composition by nuclear magnetic resonance and insulin sensitivity to explore the metabolic phenotype. Blood pressure measurements by plethysmography and vascular reactivity studies by wire myography were also performed to characterise the cardiovascular phenotype.ResultsMy‐MRKO male mice under high fat – high salt diet displayed reduced weight (37.8 g [interquartile range 34.1–40.8] vs 42.5 g [39.5–45.2]; P = 0.0128), preserved muscle mass (61.5 % [55.8–63.3] vs 56.8 % [54.1–58.5]; P = 0.0337) and a strong tendency to decreased fat mass (26.1 % [23.7–33.9] vs 31.7 % [27.1–35.4]; P = 0.0728). Moreover, liver fat content at sacrifice was decreased (5.8 % [2.1–9.1] vs 9.3 % [5.9–13.4]; P = 0.0491). Those effects were not observed in female mice. Fasting glycaemia was decreased in male My‐MRKO mice (9.2 mmol/L [6.4–12.8] vs 13.2 mmol/L [10.4–16.1]; P = 0.0005) and insulin resistance was decreased in both gender (area under curve 9915 [9398–10043] vs 11550 [9795–12848]; P = 0.0458 in males, 8291 [7812–8884] vs 9544 [8918–9735]; P = 0.0177 in females), as assessed by an insulin tolerance test. A clear effect was observed on blood pressure only in female mice (blood pressure 96 mmHg [94–97] vs 106 mmHg [104–109]; P = 0.0004), whereas there was no modification in mesenteric arteries vascular reactivity in both gender.ConclusionsThus, our findings show that myeloid cell‐MR regulates systemic metabolic parameters, highlighting a new role in obesity and its associated complications for MR expressed in myeloid cells.Support or Funding InformationSorbonne Université, Inserm, CARMMA‐RHU

Gender differences in vascular reactivity of mesenteric arterioles in portal hypertensive and non-portal hypertensive rats.

BACKGROUNDPortal hypertension (PHT) is primarily caused by an increase in resistance to portal outflow and secondarily by an increase in splanchnic blood flow. Vascular hyporeactivity both in systemic circulation and in the mesenteric artery plays a role in the hyperdynamic circulatory syndrome.AIMTo explore gender differences and the role of endogenous sex hormones in PHT and vascular reactivity of mesenteric arterioles in rats.METHODSCirrhosis and PHT were established by subcutaneous injection of carbon tetrachloride (CCl4) in both male and female integral and castrated rats (ovariectomized [OVX] in female rats, orchiectomy [ORX] in male rats). The third-order branch of the mensenteric artery was divided and used to measure vascular reactivity to vasoconstrictors.RESULTSNo significant difference in portal pressure was observed between integral and castrated male PHT rats (15.2 ± 2.1 mmHg vs 16.7 ± 2.7 mmHg, P > 0.05). The portal pressure in integral female PHT rats was lower than that in OVX female PHT rats (12.7 ± 2.7 mmHg vs 16.5 ± 2.4 mmHg, P < 0.05). In PHT rats, the concentration response curves of the mesenteric arterioles to norepinephrine were shifted to the right, and the maximal responses (Emax) values were decreased and effective concentrations causing half maximum responses (EC50) values were increased, compared to those of non-PHT rats, both in male and female rats. Compared to non-PHT integral male rats, the sensitivity of the mesenteric arterioles of non-PHT ORX male rats to norepinephrine was decreased (P > 0.05). However, there was no difference between integral and ORX male rats with PHT. In integral female PHT rats, the concentration response curves were shifted to the left (P < 0.05), and the Emax values were increased and EC50 values were decreased compared to OVX female PHT rats.CONCLUSIONClear gender differences were observed in mesenteric vascular reactivity in CCl4-induced cirrhotic and PHT rats. Conservation of estrogen can retain the sensitivity of the mesenteric arterioles to vasoconstrictors and has a protective effect on splanchnic vascular function in PHT.

Protective effect of calcium-sensing receptor inhibitor Calhex231 on traumatic hemorrhagic shock rats

Objective To observe the protective effects of calcium-sensing receptor (CaSR) inhibitor Calhex231 on traumatic hemorrhagic shock rats. Methods 144 SD rats were divided into six groups by random number table method: normal group, shock group, lactated Ringer's solution (LR) group, LR+ Calhex231 0.1 mg/kg group, LR+ Calhex231 1 mg/kg group, and LR+ Calhex231 5 mg/kg group, with 16 rats in each group for survival observation and 8 rats for hemodynamics test. 64 SD rats were divided into four groups: normal group, shock group, lactated Ringer's solution (LR) group, LR + Calhex231 1 mg/kg group, with 8 rats in each group for detecting organ blood flow and superior mesenteric artery vascular reactivity and the other 8 rats for mesenteric artery vascular reactivity. After the establishment of traumatic hemorrhagic shock model, the shock group did not receive resuscitation, and the LR group was resuscitated with LR equal to two times of the blood loss volume. The three LR+ Calhex231 groups with different dosages were firstly given LR of equal volume to that of blood loss, and then the Calhex231 was dissolved into LR ( equal to the blood loss volume) to resuscitate. The wound was ligated and sutured immediately after resuscitation. The effect of Calhex231 on animal's 24-hour survival since the beginning of resuscitation was observed. The hemodynamics including the mean arterial blood pressure(MAP), left intraventricular systolic pressure(LVSP), maximal rising, and declining rate of left intraventricular pressure (±dp/dtmax) were observed before shock, at the end of shock, 1 hour after resuscitation, and 2 hours after resuscitation. The effects of Calhex231 on vital organ blood flow and vascular reactivity were observed 2 hours after resuscitation. Results All the shock rats died within 9 hours after the shock model was established. The survival outcomes of LR group rats were slightly improved compared with the shock group rats(P<0.05) . The survival time and 24 hour survival rate of LR+ Calhex231 1 mg/kg group and LR + Calhex231 5 mg/kg group rats were significantly increased compared with the shock group rats (P<0.05). The hemodynamic indexes of LR+ Calhex231 groups were higher than those of the LR group. The best effect was observed in LR + Calhex231 1 mg/kg group rats (P<0.01). The MAP, LVSP and ±dp/dtmax were restored to normal level (64.9%, 82.4%, 89.8%, and 77.8%, respectively). Meanwhile, the blood flow in liver and kidney of LR+ Calhex231 1 mg/kg group rats were increased from 57.2% and 41% to 108.7% and 95.1%, respectively. The vascular reactivity including superior mesenteric artery and mesenteric artery of LR+ Calhex231 1 mg/kg group rats were also increased (P<0.01). Conclusions In rats with hemorrhagic shock, the calcium sensitive receptor inhibitor Calhex231 can improve the vascular reactivity, the hemodynamics, and the blood flow of important organs. It plays a role in protecting the cardiovascular function and reducing the mortality after traumatic hemorrhagic shock. Key words: Receptors, calcium-sensing; Shock, hemorrhagic; Calhex231

Redox regulation and NO/cGMP plus K+ channel activation contributes to cardiorenal protection induced by Cuphea carthagenensis (Jacq.) J.F. Macbr. in ovariectomized hypertensive rats

BackgroundOne of the medicinal plants widely used by the population in the treatment of hypertension, atherosclerosis and circulatory disorders is Cuphea carthagenensis (Jacq.) J.F. Macbr. (Lythraceae), popularly known as ‘sete sangrias’, being found in Brazil, Hawaii and in South Pacific Islands. Despite the widespread use of this species by the population, its long-term antihypertensive and cardioprotective activities have not yet been scientifically evaluated. PurposeTo evaluate the possible cardioprotective effects of an ethanol-soluble fraction obtained from C. carthagenensis (ESCC) using ovariectomized hypertensive rats to simulate a broad part of the female population over 50 years of age affected by hypertension. In addition, the molecular mechanism that may be responsible for its cardiorenal protective effects was also explored. MethodsFemale Wistar rats were submitted to surgical procedures of bilateral ovariectomy and induction of renovascular hypertension (two-kidneys, one-clip model). The sham-operated group was used as negative control. ESCC was obtained and a detailed phytochemical investigation about its main secondary metabolites was performed. ESCC was orally administered at doses of 30, 100 and 300 mg/kg, daily, for 28 days, 5 weeks after surgery. Enalapril (15 mg/kg) was used as standard antihypertensive drug. Renal function was evaluated on days 1, 7, 14, 21 and 28. At the end of the experimental period, systolic, diastolic, mean arterial pressure and heart rate were recorded. The activity of the tissue enzymatic antioxidant system, thiobarbituric acid reactive substances, nitrotyrosine, nitrite, aldosterone and vasopressin levels, in addition to the activity of the angiotensin-converting enzyme were also evaluated. Additionally, vascular reactivity to acetylcholine, sodium nitroprusside, and phenylephrine, and the role of nitric oxide, prostaglandins, and K+ channels in the vasodilator response of ESCC on the mesenteric vascular bed were also investigated. ResultsESCC-treatment induced an important cardiorenal protective response, preserving renal function and preventing elevation of blood pressure and heart rate in ovariectomized hypertensive rats. In addition, prolonged treatment with ESCC recovered mesenteric vascular reactivity at all doses used. This effect was associated with an important modulation of the antioxidant defense system with a possible increase in NO bioavailability. Additionally, NO/cGMP activation and K+ channel opening-dependent vasodilator effect was observed on the mesenteric vascular bed, indicating a potential mechanism for the cardiovascular effects of ESCC. ConclusionA 28-days ESCC treatment reduces the progression of the cardiorenal disease in ovariectomized hypertensive rats. These effects seem to be involved with an attenuation of oxidative and nitrosative stress, affecting endothelial nitric oxide production and K+ channel opening in smooth muscle cells.

CD70 Modulates the Role of eNOS In Endothelial Cells

CD70 has traditionally been identified on antigen presenting cells and interacts with CD27 on T cells, promoting proliferation and memory cell formation. We have recently shown that CD70 is important in the formation of effector memory T cells in hypertension. However, the precise cell types that express CD70 and the role of CD70 on non‐immune cells has not been investigated. Here we describe a new role of CD70 in endothelial function. We found that human umbillical vein endothelial cells express CD70 mRNA and that this is increased by &gt; 30 fold by laminar (15 dynes/cm2) compared to oscillatory shear. Studies of mesenteric vascular reactivity showed that CD70−/− mice have markedly impaired endothelium‐dependent vasodilation to acetylcholine compared to WT mice (45± 5 vs 25 ± 4 %) at baseline. In contrast, there were no differences in relaxation responses to sodium nitroprusside. Pre‐incubating vessels with the endothelial nitric oxide synthase (eNOS) inhibitor L‐NAME blocked endothelium‐dependent vasodilatation to acetylcholine in WT mice nearly 75%; in contrast, L‐NAME had no effect on endothelial vessel relaxation in CD70−/− mice. This suggests that vessels of CD70−/− mice lack the capacity to produce nitric oxide (NO). Western blot for the endothelial nitric oxide synthase (eNOS) showed a marked reduction of this enzyme in the aortas of CD70−/− as compared to wild type mice. We found that CD70 and eNOS interact by co‐immunoprecipitation, however this association is abolished by siRNA against CD70. In additional experiments, aortas from CD70−/− did demonstrate expression of both neuronal NOS (nNOS) and inducible NOS (iNOS). In order to assess functional effects of this expression, nNOS NO production was blocked with LVNIO, resulting in further impairment in vasodilation of CD70−/− mesenteric vessels (−logEC50 of 5.4 after treatment, compared to 6.2 before treatment); however blockade of iNOS with 1400 W resulted in apparent recovery of acetylcholine‐induced vasodilation. These data indicate that loss of CD70−/− leads to destabilization of the eNOS protein in endothelial cells resulting in endothelial dysfunction. In the absence of eNOS in CD70−/− vessels, iNOS contributes to endothelial dysfunction, while nNOS has a compensatory role. These studies have identified a new role of the immune co‐stimulatory protein CD70 in modulating endothelial eNOS protein levels and vascular function.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of Carvacrol on Survival, Mesenteric Blood Flow, Aortic Function and Multiple Organ Injury in a Murine Model of Polymicrobial Sepsis.

Carvacrol (CRV) has strong cytoprotective, antioxidant, and anti-inflammatory properties. We aimed to demonstrate the possible protective effects of CRV on survival, mesenteric artery blood flow (MBF), vascular reactivity, and oxidative and inflammatory injuries in a murine model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). Wistar rats were allocated into the following four groups: Sham, CLP, Sham+CRV, and CLP+CRV. The animals were orally administered with CRV (80mg/kg/day) or vehicle (corn oil; 1mL/kg/day) for 7days. At the eighth day, Sham or CLP procedure was applied. Twenty hours after the operations, MBF and contractile responses of isolated aortic preparations to phenylephrine were measured. Tissue samples were obtained for biochemical and histopathological assessments. Additionally, survival rates were recorded throughout 96h. CRV administration improved the mesenteric perfusion, contractile function of aorta, and survival after CLP. CRV substantially prevented the elevations in the levels of LDH, BUN, Cr, and inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta and interleukin-6) but could not prevent the elevations of AST and ALT after CLP. The decreased liver, kidney, and spleen glutathione levels and increased liver, kidney, lung, and spleen malondialdehyde levels induced by CLP were substantially restored by CRV. Also, histopathological protective effects of CRV on multiple organ damage due to CLP were observed. CRV possesses strong ameliorative effects on sepsis due to its protective effects on mesenteric perfusion and aortic function and its antioxidative and anti-inflammatory effects.

Fructose intake exacerbates the contractile response elicited by norepinephrine in mesenteric vascular bed of rats via increased endothelial prostanoids

Chronic fructose intake induces major cardiovascular and metabolic disturbances and is associated with the development of hypertension due to changes in vascular function. We hypothesized that high fructose intake for 6 weeks would cause metabolic syndrome and lead to initial vascular dysfunction. Male Wistar rats were assigned to receive fructose (FRU, 10%) or drinking water (CON) for 6 weeks. Systolic blood pressure was evaluated by tail plethysmography. Fasting glucose, insulin and glucose tolerance were measured at the end of the follow-up. Mesenteric vascular bed reactivity was tested before and after pharmacological blockade. Western blot analysis was performed for iNOS, eNOS, Nox2 and COX-2. DHE staining was used for vascular superoxide anion detection. Vessel structure was evaluated by optical and electronic microscopy.Fructose intake did not alter blood pressure, but did increase visceral fat deposition and fasting glucose as well as impair insulin and glucose tolerance. Fructose increased NE-induced vasoconstriction compared with CON, and this difference was abrogated by indomethacin perfusion as well as endothelium removal. ACh-induced relaxation was preserved, and the NO modulation tested after L-NAME perfusion was similar between groups. SNP-induced relaxation was not altered. Inducible NOS was increased; however, there were no changes in eNOS, Nox2 or COX-2 protein expression. Basal or stimulated superoxide anion production was not changed by fructose intake. In conclusion, high fructose intake increased NE-induced vasoconstriction through the endothelial prostanoids even in the presence of a preserved endothelium-mediated relaxation. No major changes in vessel structure were detected.

Coenzyme Q10 improves the survival, mesenteric perfusion, organs and vessel functions in septic rats

BackgroundCoenzyme Q10 (CoQ10) is a naturally occurring, lipid-soluble antioxidant and an essential electron carrier in the mitochondrial respiratory chain. In sepsis, CoQ10 deficiency induced by mitochondrial failure can lead to hypoxia, hypoperfusion, oxidative organ damage and finally death. We aimed to investigate the effects of CoQ10 on survival, mesenteric artery blood flow (MABF), vascular reactivity, oxidative and inflammatory injuries in cecal ligation and puncture (CLP)-induced sepsis. MethodsWistar rats were divided into Sham, CLP, Sham+CoQ10, CLP+CoQ10 subgroups. CoQ10 (10mg/kg/day) or vehicle (olive oil; 1mL/kg/day) was intraperitoneally injected for 15days. At 16th day, Sham or CLP operation was performed. 20h after the operations, MABF and phenylephrine responses of isolated aortic rings were measured. Tissue samples were obtained for histopathological and biochemical evaluations. Furthermore, survival rates were monitored throughout 96h. ResultsCoQ10 prevented mesenteric hypoperfusion and aortic dysfunction induced by CLP. Survival rate was %0 at 46th h in CLP group, but in CLP+CoQ10 group it was 37.5% at the end of 96h. CLP-induced elevations of serum AST, ALT, LDH, BUN, Cr and inflammatory cytokine (tumor necrosis factor-alpha, interleukin-1 beta and interleukin-6) levels were blocked by CoQ10. CoQ10 restored the increased liver, lung, spleen and kidney malondialdehyde levels and as well as reduced liver and spleen glutathione levels. The protective effects of CoQ10 on multiple organ damage were also observed histopathologically. ConclusionsCoQ10 showed protective effects in sepsis due to its preservative effects on mesenteric perfusion, aortic function and also its anti-inflammatory and antioxidative effects.

Infliximab alleviates the mortality, mesenteric hypoperfusion, aortic dysfunction, and multiple organ damage in septic rats.

Tumor necrosis factor-alpha (TNF-α) is a pivotal mediator that triggers inflammatory process, oxidative stress, and multiple organ injury in sepsis. We investigated the effects of infliximab on survival, mesenteric artery blood flow (MBF), vascular reactivity, and oxidative and inflammatory injuries in cecal ligation and puncture (CLP)-induced sepsis. Wistar rats were divided into Sham, CLP, Sham+infliximab, and CLP+infliximab subgroups. Twenty-four hours before the operations, rats were injected intraperitoneally with infliximab (7 mg/kg) or vehicle (saline; 1 mL/kg). Twenty hours after the operations, MBF and phenylephrine responses of isolated aortic rings were measured. Tissue damages were examined biochemically and histopathologically. Furthermore, survival rates were monitored throughout 96 h. Infliximab improved survival, mesenteric perfusion, and aortic function after CLP. Increases of serum AST, ALT, LDH, BUN, Cr, and inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6) induced by CLP were blocked by infliximab. Infliximab prevented malondialdehyde elevations in septic liver, lung, spleen, and kidney tissues, as well as glutathione reductions in septic liver, spleen, and kidney tissues. Protective effects of infliximab on multiple organ damage were also observed histopathologically. Infliximab showed protective effects in sepsis due to its improvement effects on mesenteric perfusion, aortic function, and its anti-inflammatory and antioxidative effects.

Purinergic signalling in mesenteric vascular smooth muscle in a mice model of essential hypertension

In vascular smooth muscle cells (VSMCs) non‐selective cation channels such as TRPC3 and TRPC6 have been proposed as the molecular constituents of receptor‐(ROCs) and stretch‐(SOCs) operated channels linking DAG signaling cascade pathway with increased vascular tone. The membrane depolarization caused by TRPCs can increase Ca2+ entry leading to augmented [Ca2+]I and VSMC contraction. Therefore, by influencing membrane potential, TRPC channels could play an important role controlling the increased vascular tone present in several pathologies, such as essential hypertension. We have previously described an increased functional expression of TRPC3 channels in mesenteric VSMCs from hypertensive mice that can contribute to increased vascular tone by favouring depolarization (Alvarez‐Miguel et al., J Physiol, in press). As several mechanosensitive G‐protein coupled receptors (GPCR) are linked to the DAG‐dependent activation of TRPC3/6 channels, we explore here the contribution of this signalling pathway to the increased vascular tone in hypertension.Using a mouse model of essential hypertension (BPH mice) and its normotensive control (BPN mice) we explored changes in the molecular components of the mechanotransduction pathway in hypertension. We analized the expression of mechanosensitive ion channels and some VSMCs sensor elements, including GPCRs, channels and transporters with qPCR. Their functional contribution was studied in isolated VSMCs (using electrophysiology) and in intact mesenteric arteries with pressure myography.Real‐time PCR showed an increased expression of some of the elements of the purinergic signalling pathway, including purinergic receptors P2Y2 and P2Y6, TRPC3 channels and the Ca2+‐activated Cl− channel Clca1. Pressure myography of mesenteric arteries after endothelium removal showed a vasoconstriction response to ATP, UTP and UDP. ATP‐induced vasoconstriction was not different between BPN and BPH arteries. The EC50 of the effect was around 7–10 μM in both preparations, and it could be blocked by α‐β‐methilene‐ATP. UTP‐induced vasoconstriction was not affected by α‐β‐methilene‐ATP and was significantly larger in BPH arteries: 50 μM UTP‐elicited vasoconstriction represented 40% of the maximal response to ATP in BPN arteries and 150% in BPH arteries. Our data indicate that mesenteric vascular reactivity to ATP is not altered in our hypertension model, but there is an increased contribution of the purinergic GPCR signalling pathway to the increased vascular tone. Together with the observed upregulation of P2YR receptors in BPH VSMCs, the augmented functional expression of TRPC3 channels could participate in the increased vasoconstriction observed in response to uridine nucleotides in BPH mesenteric arterieSupport or Funding InformationSupported by grants ISCIII‐FEDER RD12/0042/0006, (Heracles Program), BFU2013‐45867‐R (MINECO) and by a Junta de Castilla y Leon fellowship to IAM