Vascular Contraction Research Articles

Exploring the Role of Rho Kinase Enzyme in the Management of Metabolic Syndrome

Rho kinase [ROCK] enzymes are increasingly recognized for their central role in the pathogenesis of metabolic syndrome [MetS], a cluster of conditions that includes insulin resistance, hypertension, obesity, and dyslipidemia. ROCKs are serine/threonine kinases involved in the regulation of various cellular functions, including smooth muscle contraction, actin cytoskeleton organization, and gene expression. These enzymes are critically implicated in the cardiovascular and metabolic abnormalities that characterize MetS. Elevated ROCK activity has been observed in individuals with MetS, contributing to several pathogenic processes such as endothelial dysfunction, vascular inflammation, oxidative stress, and increased vascular smooth muscle contraction. These mechanisms are key drivers of hypertension and atherosclerosis, which are common complications associated with MetS. Moreover, ROCKs influence adipocyte differentiation and lipid metabolism, linking them directly to obesity and insulin resistance, two core components of the syndrome. The inhibition of ROCKs has emerged as a promising therapeutic strategy for managing MetS. Pharmacological ROCK inhibitors have shown the potential to improve insulin sensitivity, lower blood pressure, and reduce vascular inflammation and remodelling. In addition, by targeting the multiple pathways involved in the development and progression of MetS, ROCK inhibitors offer a comprehensive approach to treatment that addresses the syndrome's multifactorial nature. This therapeutic strategy not only mitigates the metabolic and cardiovascular components of the syndrome but also lowers the risk of associated complications, such as cardiovascular disease and stroke. This review concluded that interrupted Rho kinase activity contributes to the development of MetS in all its manifestations. Overall, these side effects diminish the Rho-kinase method's promise as a novel and significant treatment component.

Antioxidant and anticoagulant properties of myo-inositol determined in an ex vivo studies and gas chromatography analysis

Myo-inositol plays a key role in the vasculature and may be beneficial for preventing harmful environmental effects. In this study aortic rings were isolated from middle-aged (12-month-old) male Wistar rats and preincubated with myo-inositol (0.01–100 mg/L) for 2 h. A stable thromboxane A2 analog was added (0.1 nM, 2 h) to analyze vascular dysfunction. The concentration of myo-inositol in the organ baths was determined via gas chromatography. In another experiment, human blood plasma was subjected to pro-oxidant - hydrogen peroxide administration, and myo-inositol was added to analyze lipid and protein oxidation processes. The thromboplastin time, prothrombin time, and thrombin time were also studied. Myo-inositol administration protected thiol groups against oxidative stress, meanwhile decreased vascular contraction and potentiated vasodilation (concentrations 1–100 mg/L, but not ≤ 0.1 mg/L), and changed the level of 8-isoprostane (concentrations: 0.1–100 mg/L, but not 0.01 mg/L) in plasma treated with H2O2/Fe2+. A dose above 100 mg/L additionally protected lipids (measured as thiobarbituric acid reactive substances) and increased thrombin time. Moreover, significant differences in vascular relaxation were observed between the studied myo-inositol concentrations (1 vs. 10 vs. 100 mg/L), which was not detected under the 0.1 mg/L. The concentration of myo-inositol in the organ baths determined via gas chromatography revealed that this nutraceutical agent was not used by the aortic rings during the incubation period in physiological processes. A protective effect of myo-inositol against prooxidant damage to human plasma and rat thoracic arteries has been demonstrated.

Transcriptomic analysis reveals differentially expressed genes associated with meat quality in Chinese Dagu chicken and AA+ broiler roosters

BackgroundWith the improvement of living standards, the quality of chicken has become a significant concern. Chinese Dagu Chicken (dual-purpose type) and Arbor Acres plus broiler (AA+ broiler) (meat-type) were selected as the research subjects in this study, the meat quality of the breast and leg muscles were measured. However, the molecular mechanism(s) underlying regulation of muscle development are not yet fully elucidated. Therefore, finding molecular markers or major genes that regulate muscle quality has become a crucial breakthrough in chicken breeding. Unraveling the molecular mechanism behind meat traits in chicken and other domestic fowl is facilitated by identifying the key genes associated with these developmental events. Here, a comparative transcriptomic analysis of chicken meat was conducted on breast muscles (BM) and leg muscles (LM) in AA+ broilers (AA) and Dagu chicken (DG) to explore the differences in their meat traits employing RNA-seq.ResultsTwelve cDNA libraries of BM and LM from AA and DG were constructed from four experimental groups, yielding 14,464 genes. Among them, Dagu chicken breast muscles (DGB) vs AA+ broilers breast muscles (AAB) showed 415 upregulated genes and 449 downregulated genes, Dagu chicken leg muscles (DGL) vs AA+ broilers leg muscles (AAL) exhibited 237 upregulated genes and 278 downregulated genes, DGL vs DGB demonstrated 391 upregulated genes and 594 downregulated genes, and AAL vs AAB displayed 122 upregulated genes and 154 downregulated genes. 13 genes, including nine upregulated genes (COX5A, COX7C, NDUFV1, UQCRFS1, UQCR11, BRT-1, FGF14, TMOD1, MYOZ2) and four downregulated genes (MYBPC3, MYO7B, MTMR7, and TNNC1), were found to be associated with the oxidative phosphorylation signaling pathway. Further analysis revealed that the differentially expressed genes (DEGs) from muscle were enriched in various pathways, such as metabolic pathways, oxidative phosphorylation, carbon metabolism, glycolysis, extracellular matrix-receptor interaction, biosynthesis of amino acids, focal adhesion, vascular smooth muscle contraction, and cardiac muscle contraction, all of which are involved in muscle development and metabolism. This study also measured the meat quality of the breast and leg muscles from the two breeds, which demonstrated superior overall meat quality in Chinese Dagu Chicken compared to the AA+ broiler.ConclusionsOur findings show that the meat quality of dual-purpose breeds (Chinese Dagu chicken) is higher than meat-type (AA+ broiler), which may be related to the DEGs regulating muscle development and metabolism. Our findings also provide transcriptomic insights for a comparative analysis of molecular mechanisms underlying muscle development between the two breeds, and have practical implications for the improvement of chicken breeding practices.

The landscape of N1-methyladenosine (m1A) modification in mRNA of the decidua in severe preeclampsia.

Recent discoveries in mRNA modification have highlighted N1-methyladenosine (m1A), but its role in preeclampsia (PE) pathogenesis remains unclear. In this study, we utilized methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) to identify m1A peaks and the expression profile of mRNA in the decidua of humans with early-onset PE (EPE), late-onset PE (LPE), and normal pregnancy (NP). We assessed the m1A modification patterns in preeclamptic decidua using 10 m1A modulators. Our bioinformatic analysis focused on differentially methylated mRNAs (DMGs) and differentially expressed mRNAs (DEGs) in pairwise comparisons of EPE vs. NP, LPE vs. NP, and EPE vs. LPE, as well as m1A-related DEGs. The comparisons of EPE vs. NP, LPE vs. NP, and EPE vs. LPE identified 3110, 2801, and 2818 DMGs, respectively. We discerned three different m1A modification patterns from this data. Further analysis revealed that key PE-related DMGs and m1A-related DEGs predominantly influence signaling pathways critical for decidualization, including cAMP, MAPK, PI3K-Akt, Notch, and TGF-β pathways. Additionally, these modifications impact pathways related to vascular smooth muscle contraction, estrogen signaling, and relaxin signaling, contributing to vascular dysfunction. Our findings demonstrate that preeclamptic decidua exhibits unique mRNA m1A modification patterns and gene expression profiles that significantly alter signaling pathways essential for both decidualization and vascular dysfunction. These differences in m1A modification patterns provide valuable insights into the molecular mechanisms influencing the decidualization process and vascular function in the pathogenesis of PE. These m1A modification regulators could potentially serve as potent biomarkers or therapeutic targets for PE, warranting further investigation.

Impaired Endothelium-Dependent Vasodilation and Increased Levels of Soluble Fms-like Tyrosine Kinase-1 Induced by Reduced Uterine Perfusion Pressure in Pregnant Rats: Evidence of Protective Effects with Sodium Nitrite Treatment in Preeclampsia.

Preeclampsia (PE) is a hypertensive disorder of pregnancy and is associated with increases in soluble fms-like tyrosine kinase-1 (sFlt-1) and reductions in nitric oxide (NO) levels. Placental ischemia and hypoxia are hypothesized as initial pathophysiological events of PE. Nitrite (NO metabolite) may be recycled back to NO in ischemic and hypoxic tissues. Therefore, this study examined the sodium nitrite effects in an experimental model of PE. Pregnant rats received saline (Preg group) or sodium nitrite (Preg + Na-Nitrite group). Pregnant rats submitted to the placental ischemia received saline (RUPP group) or sodium nitrite (RUPP + Na-Nitrite group). Blood pressure, placental and fetal weights, and the number of pups were recorded. Plasma levels of NO metabolites and sFlt-1 were also determined. Vascular and endothelial functions were also measured. Blood pressure, placental and fetal weights, the number of pups, NO metabolites, sFlt-1 levels, vascular contraction, and endothelium-dependent vasodilation in the RUPP + Na-Nitrite rats were brought to levels comparable to those in Preg rats. In conclusion, sodium nitrite may counteract the reductions in NO and increases in sFlt-1 levels induced by the placental ischemia model of PE, thus suggesting that increased blood pressure and vascular and endothelial dysfunctions may be attenuated by sodium nitrite-derived NO.

Regulation of vascular smooth muscle cell contraction during early postnatal ontogenesis

Growth of the body in early postnatal ontogenesis is associated with changes in the functioning of many organ systems, including the cardiovascular system. The circulatory system of newborns is characterized by numerous structural and functional features, which at the systemic level is manifested in a significantly lower level of blood pressure. This review describes the differences in the mechanisms of regulation of vascular smooth muscle cell contraction in early postnatal ontogenesis and in adulthood, including age-related changes in the functioning of ion channels, which activity affects membrane potential level and intracellular concentration of calcium ions, as well as changes in calcium sensitivity of the contractile apparatus. The final section of the review discusses the connection between the mechanisms regulating contraction and differentiation of vascular smooth muscle cells during maturation.

Prolonged Copper Supplementation Modified Minerals in the Kidney, Liver and Blood, and Potentiated Oxidative Stress and Vasodilation of Isolated Aortic Rings in Young Wistar Rats.

Previous studies have highlighted that copper supplementation at 200% of the recommended daily dietary allowance modified vascular contraction and relaxation through increased reactive oxygen species (ROS) and prostaglandin formation, which modified the antioxidant status of middle-aged Wistar rats. In this study, young (1 month old) male Wistar rats (n/group = 10) received a diet supplemented with 6.45 mg copper/kg (100% of daily recommendation-Group A) for 8 weeks. The experimental group received 12.9 mg copper/kg of diet (200% of the daily recommendation-Group B). Experimental supplementation with 200% copper modified the copper concentration in the blood (1.21-fold, p = 0.04), liver (1.15-fold, p = 0.032), and kidneys (1.23-fold, p = 0.045), potentiated the ROS formation in the aortic rings, and enhanced the sensitivity of the aortic rings to the vasodilator acetylcholine. We observed an increased participation of nitric oxide (NO) derived from inducible NO synthase (iNOS) in vascular contraction and a decreased net effect of vasodilator prostanoids derived from cyclooxygenase-2 in vascular relaxation. In rat kidneys, the concentrations of potassium (1.08-fold, p = 0.001) and iron (1.13-fold, p = 0.046) were higher, while, calcium (0.88-fold, p = 0.001) and chromium (0.77-fold, p = 0.005) concentrations were lower. In the rat liver, magnesium (1.06-fold, p = 0.012) was higher. No differences were observed in the concentrations of sodium, zinc, manganese, selenium, cobalt, molybdenum, and vanadium. The antioxidant activity of water- and lipid-soluble compounds; total antioxidant status in the blood; and superoxide dismutase, catalase, and malondialdehyde levels in the heart did not change. In young rats, prolonged supplementation with 200% copper had a lesser effect than anticipated on oxidative stress and vascular reactivity. Detailed data on the status of trace elements and their interactions in patients of different age groups are strongly required for effective nutritional and therapeutic intervention.

226 Serotonin stimulates relaxation in ovine saphenous vein precontracted with ergovaline

Abstract The predominant ergot alkaloid found in wild type endophyte-infected tall fescue grass is ergovaline. Ergovaline is a potent vasoconstrictor in livestock that consume it. Previous research has shown that ergovaline can bind serotonin (5-HT) receptors and blood vessels exposed to ergovaline become unresponsive to subsequent 5-HT exposure. Serotonin can stimulate vascular contraction or relaxation depending on the receptor subtype targeted. The objective of this experiment was to evaluate 5HT as vasorelaxant in the ovine saphenous artery and vein that were precontracted with ergovaline. Blood vessels were collected from mixed breed market rams (n = 7) at slaughter, cleaned of surrounding adipose and connective tissue, sliced into 2-mm cross-sections, and mounted in a multimyograph. Artery and vein cross-sections were equilibrated to 1 g tension in continuously gassed (95% O2/5% CO2) Krebs-Henseleit buffer (pH 7.4; 37.5 °C) for 90 min, precontracted with 1.0 μM ergovaline (in a tall fescue seed extract) for 30 min, exposed to increasing concentrations of 5-HT that ranged from 1 x 10-9 to 1 x 10-4 M for a 5-min interval. Response data were normalized to the 1.0 μM ergovaline response and were analyzed as a completely randomized design in SAS. The saphenous vein was larger in diameter blood vessel than the saphenous artery. Both vessel types contracted in response to exposure to 1 μM ergovaline. The saphenous artery had a much lower maximal response to ergovaline than did the vein (P < 0.05) that could be attributed to the size difference. The lateral saphenous vein relaxed to increasing concentrations of 5-HT (P < 0.05) with 87 % relaxation occurring by 1 x 10-6 M 5-HT. Conversely, the lateral saphenous artery contracted in response to increasing concentrations of 5-HT (P < 0.05) resulting in a 43% increase from the ergovaline response by the 1 x 10-4 M addition. This response did not become significant in the artery until 1 x 10-5 M 5-HT compared with 1 x 10-8 M for the vein. This resulted in a 50% effective concentration for 5-HT in the artery of 4.5 compared with 8.1 M for the vein (P < 0.05). The differing responses across vessels are likely a result of different receptor populations and this should be verified in future research. This is the first reported observation of stimulated relaxation of a blood vessel constricted ergovaline. Additional research is needed to understand the mechanism of how 5HT can be used to stimulate vasorelaxation in livestock suffering from ergot alkaloid-induced vasoconstriction.

Endothelin-1 down-regulates nuclear factor erythroid 2-related factor-2 and contributes to perivascular adipose tissue dysfunction in obesity.

Perivascular adipose tissue (PVAT) negatively regulates vascular muscle contraction. However, in the context of obesity, the PVAT releases vasoconstrictor substances that detrimentally affect vascular function. A pivotal player in this scenario is the peptide endothelin-1 (ET-1), which induces oxidative stress and disrupts vascular function. The present study postulates that obesity augments ET-1 production in the PVAT, decreases the function of the nuclear factor erythroid 2-related factor-2 (Nrf2) transcription factor, further increasing reactive oxygen species (ROS) generation, culminating in PVAT dysfunction. Male C57BL/6 mice were fed either a standard or a high-fat diet for 16 weeks. Mice were also treated with saline or a daily dose of 100 mg·kg-1 of the ETA and ETB receptor antagonist Bosentan, for 7 days. Vascular function was evaluated in thoracic aortic rings, with and without PVAT. Mechanistic studies utilized PVAT from all groups and cultured WT-1 mouse brown adipocytes. PVAT from obese mice exhibited increased ET-1 production, increased ECE1 and ETA gene expression, loss of the anticontractile effect, as well as increased ROS production, decreased Nrf2 activity, and downregulated expression of Nrf2-targeted antioxidant genes. PVAT of obese mice also exhibited increased expression of Tyr216-phosphorylated-GSK3β and KEAP1, but not BACH1 - negative Nrf2 regulators. Bosentan treatment reversed all these effects. Similarly, ET-1 increased ROS generation and decreased Nrf2 activity in brown adipocytes, events mitigated by BQ123 (ETA receptor antagonist). These findings place ET-1 as a major contributor to PVAT dysfunction in obesity and highlight that pharmacological control of ET-1 effects restores PVAT's cardiovascular protective role.

Abstract P231: Self-administration of Remifentanil Induces Endothelial Dysfunction in Thoracic Aorta and Impaired Cavernosal Reactivity of Wistar Rats

Aims: Recent studies have implicated the use of prescription opioids as a risk factor for cardiovascular diseases (CVD), with associations including myocardial infarction, coronary artery disease and vascular deterioration. Further, opioid-dependent patients show increased vascular aging and arterial stiffness when compared to opioid-naïve controls. Our hypothesis was that rats dependent on remifentanil (a fentanyl analog) after a 12-day operant self-administration (SA) study lead to vascular dysfunction in thoracic aorta. Because erectile dysfunction (ED) is associated with arterial stiffness and is positively correlated with its severity, we hypothesized that opioid SA impaired corpus cavernosum (CC) reactivity as well. Methods: Male Wistar rats (12 weeks-old) were implanted with intravenous catheters and learned to lever press (FR1) for remifentanil (1µg/kg/infusion). A separate group of rats received passive yoked infusions of saline administered in synchrony with remifentanil-treated animals to control volumetric vascular effects. Following administration, animals were euthanized, and aorta and CC collected to evaluate function using both pin and strip myographs. Concentration-response curves to phenylephrine (Phe; 10 -11 -10 -4 M), sodium nitroprusside (SNP) and acetylcholine (Ach or SNP; 10 -10 -10 -4 M) were performed to test contractility and endothelium-independent and -dependent relaxation respectively. Results: Remifentanil-treated rats showed rapidly acquired SA behavior, exhibiting robust and selective drug-paired lever pressing when compared to the non-drug paired lever. In contrast, yoked saline-treated controls rarely exhibited lever pressing. Endothelium-dependent relaxation in the aorta was diminished in the remifentanil group (Rmax: Control: 68.7±2.7 vs. Remi: 47.8±3.7%; p<0.05). There were no observed alterations in endothelium-independent relaxation or vascular contraction. However, CC contraction was slightly shifted to the right in remifentanil treated rats (pEC 50 : Control: 6.04±0.09 vs. Remi: 5.66±0.12; p<0.05). No changes were observed in the CC relaxant response. These findings indicate that 12 days of remifentanil administration results in endothelial dysfunction in large arteries and impaired cavernosal reactivity. Long-term exposure may lead to aortic stiffness exacerbating ED severity and increases in pulse-wave velocity in opioid-dependent patients contributing to the onset of hypertension.

Abstract 62: Notch3 and the Vascular-Adipose Interactome in the Regulation of Adiponectin and Vascular Contraction

Notch3, a cell-cell interaction receptor expressed in VSMCs, is important in vascular function. Notch3 mutations cause CADASIL and aberrant Notch3 signaling is associated with vascular dysfunction/remodeling of resistance arteries, similar to the vascular phenotype in hypertension. Recent evidence suggests that Notch receptors, including Notch3, also play a role in adipose biology. Based on our previous findings that aberrant Notch3 signaling leads to vascular injury, and that perivascular adipose tissue influences vascular function we investigated a potential role for Notch3 in the vascular-adipose interactome. We characterized adipose tissue (AT) [brown AT (BAT) and white AT (WAT)] and vascular function in mice overexpressing Notch3 (N3) and in mice harboring the R169C gain of function Notch3 mutation (RC). We evaluated expression of Notch3, and its target transcription factors, BAT markers (UCP-1, OTOP-1), and production of adiponectin and IL-6. Isolated arteries from control mice were exposed to BAT conditioned medium (CM) and vascular function assessed by myography. We did not observe any changes in body weight, but BAT (N3: 115.4±7.1; RC: 115.3±8.2; WT: 154±12.1 mg, p<0.05) and WAT (N3: 309.7±39; RC: 370.4±41; WT: 618.1±73 mg, p<0.05) were decreased in N3 and RC mice. Expression of Notch3 target genes (Heyl, Hes5) was increased in BAT from N3 and RC mice. This was associated with increased production of adiponectin (N3: 25.1±0.4; RC: 25.8±0.6; WT: 23.6±0.4 pg/µg of tissue, p<0.05) and IL-6 (N3: 45.3±5.6; RC: 51.6±5.1; WT: 33.7±2.1 pg/µg of tissue, p<0.05) (by ELISA). UCP-1 expression was increased in WAT from Notch3 mice versus wildtype. Vascular contraction to U46619 was reduced by BAT CM from WT mice (EMax: 158.5±9.7% vs control 183.6±6%). This effect was enhanced with BAT CM from Notch3 (N3 and RC) mice. WAT CM from N3 and RC mice reduced vascular sensitivity to contraction (logEC50: N3=7.2±0.17M; RC=7.2±0.1M; WT: 7.7±0.1M, p<0.05). In summary, at the molecular level, Notch3 regulates adipose tissue, with increased production of adiponectin in BAT and increased expression of browning markers in WAT. Functionally BAT from Notch3 mice attenuates vasoconstriction in WT mice. Our data suggest a putative role for Notch3 in the vasoprotective effects of BAT. These novel findings suggest an important role for Notch3 in the vascular:adipose interactome. Notch3 activation may influence vascular function, in part, by regulating perivascular BAT/WAT.

Effects of Platelet-Activating Factor (PAF) on the Mechanical Activities of Lower Urinary Tract and Genital Smooth Muscles.

Since its first discovery as a bioactive phospholipid inducing potent platelet aggregation, platelet-activating factor (PAF) has been shown to be involved in a wide variety of inflammatory and allergic disease states. Many pharmacological studies in the 1980s and 1990s also showed that PAF induces endothelium-dependent vascular relaxation and contraction of various smooth muscles (SMs), including those in the airway, gastrointestinal organs, and uterus. However, since the late 1990s, there have been few reports on the SM contractions induced by PAF. The lower urinary tract (LUT), particularly the urinary bladder (UB) has attracted recent attention in SM pharmacology research because patients with LUT dysfunctions including overactive bladder are increasing as the population ages. In addition, recent clinical studies have implicated the substantial role of PAF in the inflammatory state in LUT because its production increases with smoking and with cancer. However, the effects of PAF on mechanical activities of LUT SMs including UBSM have not been investigated to date. Recently, we found that PAF very strongly increased mechanical activities of UBSM in guinea pigs and mice, and partly elucidated the possible mechanisms underlying these actions of PAF. In this review, we describe the effects of PAF on LUT SMs by introducing our recent findings obtained in isolated UBSMs and discuss the physiological and pathophysiological significance. We also introduce our data showing the effects of PAF on the SM mechanical activities of genital tissues (prostate and vas deferens).

Abstract 12: Deficiency of Progranulin Decreases Mitochondrial Function and Induces a Whitening Phenotype in Perivascular Adipose Tissue, Suppressing Its Anti-Contractile Effects

Perivascular adipose tissue (PVAT) is recognized as an endocrine organ that secretes a variety of adipokines, which negatively regulate vascular contraction. Progranulin (PGRN), a glycoprotein encoded by the GRN gene, is highly expressed in adipocytes, and is implicated in inflammation, cellular proliferation, and repair mechanisms. The relationship between PGRN and PVAT remains unclear. We hypothesized that the lack of PGRN negatively affects PVAT quality. We used male C57BL/6J wild-type (WT) and global PGRN knockout (KO) mice, aged 10-12 weeks. Energy expenditure was analyzed via the Comprehensive Lab Animal Monitoring System (CLAMS). Vascular function was studied in endothelium-intact aortae with PVAT [PVAT(+)] and without PVAT [PVAT(-)]. Additionally, 3T3-L1 cells were used to evaluate the molecular mechanisms. The KO mice showed a decreased respiratory exchange ratio (RER) and a whitening phenotype of PVAT, which was accompanied by a loss of anti-contractile effects [(mN) WT_PVAT(-): 5.2±0.3 vs PVAT(+): 3.4±0.5*, *P<0.05 and KO_PVAT(-): 6.1±0.7 vs KO_PVAT(+): 5.7±0.4]. Additionally, PVAT from KO displayed a significant reduction in nitric oxide production [(RFU) WT_PVAT: 223.1± 12.3 vs KO_PVAT: 67.3±9.1*, *P<0.05] and endothelial NO synthase phosphorylation. Additionally, the lack of PGRN attenuated the expression of mitochondrial complexes [(AU) WT_PVAT: 1.3± 0.03 vs KO_PVAT: 0.6±0.06*, *P<0.05] measured by the OXPHOS cocktail antibody. Via high-resolution respirometry, we found that isolated mitochondria from KO_PVAT showed impaired succinate-driven respiration or complex II activity. To understand if the whitening phenotype of PVAT was leading to its dysfunction, we induced a browning phenotype of PVAT by treating the mice with a β3-agonist for 7 days (CL 316243, 1mg/kg/day). This treatment increased RER restored the PVAT phenotype, and improved PVAT anti-contractile effect and mitochondrial respiration. Using 3T3-L1 cells, we engineered the overexpression and knockdown of PGRN via lentivirus (LV) infection and siRNA, respectively. Suppression of PGRN increased mRNA of whitening markers (1.5-fold increase vs scramble siRNA), while overexpression elevated mRNA of browning and mitochondrial markers (1.3-fold increase vs scramble LV). In summary, our findings reveal that PGRN is crucial for maintaining the phenotype and anti-contractile function of PVAT and highlight PGRN as a pharmacological target for vascular outcomes in cardiometabolic conditions.

Abstract MP16: Expression of an AT 1 R Receptor Mutant which Genetically Biases Gαq Specifically in Vascular Smooth Muscle Cell Causes Hypertension and Enhanced Vascular Contraction

Angiotensin II (ANG) type 1 receptor (AT 1 R) belongs to the 7-membrane superfamily of G protein-coupled receptors (GPCR) which have the largest class of drug targets. AT 1 Rs can adopt different conformations that can bias G-protein coupling (particularly Gaq) or b-arrestin signaling. The b-arrestin pathway is reported to be cardioprotective while the canonical Gaq-dependent pathway is typically associated with the detrimental effects of ANG. We hypothesize that selective and inducible activation of the AT 1 R Gaq pathway in the absence of b-arrestin signaling in vascular smooth muscle (SMC) results in hypertension and vascular dysfunction via an AT 1 R-dependent mechanism. We generated an AT 1 R mutant (AT 1 R TSTS-AAAA ) which ablates the phosphorylation sites for GPCR kinases (GRK) in the C-terminal to impair b-arrestin recruitment and to induce a Gaq bias. Transgenic mice were made with a construct that induces both AT 1 R TSTS-AAAA and tdTomato expression in response to Cre-recombinase. Primary fibroblasts cultured from AT 1 R TSTS-AAAA mice exhibited a Cre-induced expression of tdTomato and marked increase in phosphorylated-extracellular signal-regulated kinase (P-ERK) in response to ANG when compared to mice cells expressing wildtype AT 1 R. Mice carrying inducible AT 1 R TSTS-AAAA were bred with tamoxifen-inducible SMC-specific CRE (SMC CreERT2 , S-TSTS) mice. Transgene expression in S-TSTS mice was successfully activated by tamoxifen as measured by the expression of the embedded tdTomato reporter in the aorta SMC. S-TSTS mice exhibited a trend of increased systolic blood pressure (SBP) 1 week after tamoxifen injection (147.76 ± 13.21 vs. 108.85 ± 4.58 mmHg). Candesartan (10 mg/kg/day in drinking water) was then administered to S-TSTS mice once hypertension was established. Candesartan treatment for 1 week reversed the hypertension in S-TSTS mice (100.00 ± 2.88 mmHg). Interestingly, 2 weeks after ending candesartan treatment, SBP was once again elevated in S-TSTS mice (142.01 ± 7.65 vs. 90.35 ± 1.14 mmHg, p<0.05). In addition, mesenteric arteries from transgenic mice exhibited a robust increase in ANG-induced constriction when compared to control mice (ANG, max constriction 60.25 ± 4.78% vs. 14.12 ± 4.72%, p<0.05). Our findings support the hypothesis that signaling through the Gaq-dependent pathway in SMC leads to increased vasoconstriction and hypertension through an AT 1 R-dependent mechanism.

The Potential Mechanisms of Catechins in Tea for Anti-Hypertension: An Integration of Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation.

Catechins, a class of polyphenolic compounds found in tea, have attracted significant attention due to their numerous health benefits, particularly for the treatment and protection of hypertension. However, the potential targets and mechanisms of action of catechins in combating hypertension remain unclear. This study systematically investigates the anti-hypertensive mechanisms of tea catechins using network pharmacology, molecular docking, and molecular dynamics simulation techniques. The results indicate that 23 potential anti-hypertensive targets for eight catechin components were predicted through public databases. The analysis of protein-protein interaction (PPI) identified three key targets (MMP9, BCL2, and HIF1A). KEGG pathway and GO enrichment analyses revealed that these key targets play significant roles in regulating vascular smooth muscle contraction, promoting angiogenesis, and mediating vascular endothelial growth factor receptor signaling. The molecular docking results demonstrate that the key targets (MMP9, BCL2, and HIF1A) effectively bind with catechin components (CG, GCG, ECG, and EGCG) through hydrogen bonds and hydrophobic interactions. Molecular dynamics simulations further confirmed the stability of the binding between catechins and the targets. This study systematically elucidates the potential mechanisms by which tea catechins treat anti-hypertension and provides a theoretical basis for the development and application of tea catechins as functional additives for the prevention of hypertension.

Is there a role for biogenic amine receptors in mediating β-phenylethylamine and RO5256390-induced vascular contraction?

BackgroundSubstantial evidence indicates trace amines can induce vasoconstriction independently of noradrenaline release. However, the mechanism underlying noradrenaline-independent vasoconstrictor responses to trace amines has not yet been established. This study evaluates the role of trace amine-associated receptor 1 (TAAR1) and other biogenic amine receptors in mediating β-phenylethylamine and the TAAR-1 selective agonist RO5256390-induced vasoconstriction. MethodsVasoconstrictor responses to β-PEA and the TAAR1-selective agonist, RO5256390 were assessed in vitro in endothelium-denuded aortic rings and third-order mesenteric arteries of male Sprague Dawley rats. Resultsβ-PEA and RO5256390 induced concentration-dependent vasoconstriction of aortic rings but not third-order mesenteric arteries. Vasoconstrictor responses in aortic rings were insensitive to antagonists of 5-HT. The murine-selective TAAR1 antagonist, EPPTB, had no effect on either β-PEA or RO5256390-induced vasoconstriction. The α1-adrenoceptor antagonist, prazosin, and the α2-adrenoceptor antagonist, yohimbine, induced a shift of the β-PEA concentration response curve too small to be ascribed to antagonism of α1-or α2-adrenoceptors, respectively. The α2-adrenoceptor antagonist atipamezole had no effect on β-PEA or RO5256390-induced vasoconstriction. ConclusionVasoconstrictor responses to trace amines are not mediated by classical biogenic amine neurotransmitter receptors. Insensitivity of β-PEA vasoconstrictor responses to EPPTB, may be explained by its low affinity for rat rather than murine TAAR1. Therefore, TAAR1 remains the most likely candidate receptor mediating vasoconstrictor responses to trace amines and that prazosin and yohimbine have low affinity for TAAR1.

Low Calcium-High Magnesium Krebs-Henseleit Solution Combined with Adenosine and Lidocaine Improved Rat Aortic Function and Structure Following Cold Preservation.

Background and objectives: The main problem of vascular preservation is the maintenance of vessel graft quality and function following extended storage. Conventional preservation solutions such as histidine-tryptophan-ketoglutarate (HTK) solution, Phosphate-Buffer Solution (PBS), or sodium chloride 0.9% has been shown to be inadequate in preserving vascular physiological function after 3 days of cold storage. This study aimed to evaluate whether adenosine and lidocaine (AL) in a modified Krebs-Henseleit (KH) solution can preserve the function and histological structure of rat aortic rings after 6 days. Materials and Methods: Thirty-five aortic rings from male Wistar rats (200-300 g) were harvested and immediately immersed in one of the assigned cold preservation solutions: standard KH, modified KH (mod KH) with lower calcium (Ca2+) and higher magnesium content (Mg2+) with or without adenosine and lidocaine (mod KH-AL), and modified KH with AL, insulin, and melatonin (Mod KH-ALMI). The contraction and relaxation function of the aortic rings were examined using an isometric force transducer after 6 days of cold preservation. Hematoxylin and eosin staining were used to analyze the rings' histological structure. Results: Vascular contraction and relaxation functions were severely affected after a 6-day cold storage period in standard KH. Modifying the KH solution by reducing the Ca2+ and increasing the Mg2+ levels greatly recovered the vessel functions. The addition of AL or ALMI to the modified KH did not further recover vascular contractility. However, only the addition of AL to the modified KH increased the ACh-induced relaxation at 6 days when compared to the conventional KH, suggesting that endothelium preservation is improved. From histological analysis, it was found that the addition of AL but not ALMI further improved the endothelial lining and the structure of the elastic membrane layers of the preserved vessels after 6 days of cold preservation. Conclusions: The addition of AL to low calcium-high magnesium KH solution significantly enhanced endothelial preservation and improved endothelial-induced relaxation of preserved vessels after 6 days of cold storage.

Pharmacological mechanisms by which baicalin ameliorates cardiovascular disease.

Baicalin is a flavonoid glycoside obtained from the dried root of Scutellaria baicalensis Georgi, which belongs to the Labiatae family. Accumulating evidence indicates that baicalin has favorable therapeutic effects on cardiovascular diseases. Previous studies have revealed the therapeutic effects of baicalin on atherosclerosis, myocardial ischemia/reperfusion injury, hypertension, and heart failure through anti-inflammatory, antioxidant, and lipid metabolism mechanisms. In recent years, some new ideas related to baicalin in ferroptosis, coagulation and fibrinolytic systems have been proposed, and new progress has been made in understanding the mechanism by which baicalin protects cardiomyocytes. However, many relevant underlying mechanisms remain unexplained, and much experimental data is lacking. Therefore, further research is needed to determine these mechanisms. In this review, we summarize the mechanisms of baicalin, which include its anti-inflammatory and antioxidant effects; inhibition of endothelial cell apoptosis; modulation of innate immunity; suppression of vascular smooth muscle cells proliferation, migration, and contraction; regulation of coagulation and fibrinolytic systems; inhibition of myocardial hypertrophy; prevention of myocardial fibrosis; and anti-apoptotic effects on cardiomyocytes.

Decreased vascular contraction and changes in oxidative state in middle–aged Wistar rats after exposure to increased levels of dietary zinc

Both copper and zinc are known to be important for maintaining health, but most research has focused on deficiencies of these elements. Recent studies have shown that high levels of Cu can be toxic, especially to the cardiovascular (CV) system. However, little research has been done on the effects of higher levels of Zn on the CV system. In this study, male Wistar rats aged 12 months were given a diet with twice the recommended daily allowance of zinc (31.8 mg/kg of diet) and compared to a control group (15.9 mg/kg of diet) after 8 weeks. Blood plasma and internal organs of both groups were examined for levels of copper, zinc, selenium and iron, as well as several key enzymes. Aortic rings from both groups were also examined to determine vascular functioning. There were very few changes in the vascular system functioning after chronic exposure to zinc, and only one enzyme, heme oxygenase–1 (HO–1) was elevated, whereas vascular contraction to noradrenaline decreased with no changes in vasodilation to acetylcholine. Of the micronutrients, zinc and selenium were elevated in the blood plasma, while copper decreased. Meanwhile, the total antioxidant status increased. These were not observed in the liver. Therefore, it is proposed that there is a mechanism in place within the vascular system to protect against the overproduction of heme, caused by chronic zinc exposure.

Effect of Torilis japonica Fruit Extract for Endothelium-Independent Vasorelaxation and Blood Pressure Lowering in Rats.

Torilis japonica (TJ) fruit, is a herb that is traditionally used for erectile dysfunction (ED). Given the shared mechanisms of ED and hypertension through vascular smooth muscle, we hypothesized that TJ would be effective in vasodilation and blood pressure reduction. This study confirmed the authenticity of TJ samples via DNA barcoding and quantified the main active compound, torilin, using HPLC. TJ was extracted with distilled water (TJW) and 50% ethanol (TJE), yielding torilin contents of 0.35 ± 0.01% and 2.84 ± 0.02%, respectively. Ex vivo tests on thoracic aortic rings from Sprague-Dawley rats showed that TJE (3-300 µg/mL) induced endothelium-independent, concentration-dependent vasodilation, unlike TJW. Torilin caused concentration-dependent relaxation with an EC50 of 210 ± 1.07 µM. TJE's effects were blocked by a voltage-dependent K+ channel blocker and alleviated contractions induced by CaCl2 and angiotensin II. TJE inhibited vascular contraction induced by phenylephrine or KCl via extracellular CaCl2 and enhanced inhibition with nifedipine, indicating involvement of voltage-dependent and receptor-operated Ca2+ channels. Oral administration of TJE (1000 mg/kg) significantly reduced blood pressure in spontaneously hypertensive rats. These findings suggest TJ extract's potential for hypertension treatment through vasorelaxant mechanisms, though further research is needed to confirm its efficacy and safety.