Adrenomedullin improved endothelial dysfunction via receptor-Akt pathway in rats with obesity-related hypertension.

Obesity-related hypertension (OH) is accompanied by obvious endothelial dysfunction, which contributes to increased peripheral vascular resistance and hypertension. Adrenomedullin (ADM), a multifunctional active peptide, is elevated in obese humans. The OH rats induced by high fat diet (HFD) for 28 weeks and the human umbilical vein endothelial cells (HUVECs)-treated by palmitic acid (PA) were used to investigate the effects of ADM on endothelial dysfunction and the underlying mechanisms. Vascular reactivity was assessed using mesenteric arteriole rings, and the protein expression levels were examined by Western blot analysis. Compared with the control rats, OH rats exhibited hypertension and endothelial dysfunction, along with reduced eNOS protein expression and Akt activation, and increased protein expression of proinflammatory cytokines and ROS levels. Four-week ADM administration improved hypertension and endothelial function, increased eNOS protein expression and Akt activation, and attenuated endothelial inflammation and oxidative stress in OH rats. In vitro experiment, the antagonism of ADM receptors with ADM22-52 and the suppression of Akt signaling with A6730 significantly blocked ADM-caused increase of NO content and activation of eNOS and Akt, and inhibited the anti-inflammatory and anti-oxidant effect of ADM in PA-stimulated HUVECs. These data indicate that endothelial dysfunction in OH rats is partially attributable to the decreased NO level, and the increased inflammation and oxidative stress. ADM improves endothelial function and exerts hypotensive effect depending on the increase of NO, and its anti-inflammatory and anti-oxidant effect via receptor-Akt pathway.

Predictors of Cardiac Autonomic Dysfunction in Obesity-Related Hypertension.

INTRODUCTION: Cardiac Autonomic Dysfunction (CAD) is an overlooked cardiovascular risk factor in individuals with obesity-related hypertension. Despite its clinical significance, there is a notable lack of clarity regarding the pathophysiological correlates involved in its onset and progression. AIM: The present study aimed to identify potential predictors of CAD in obesity-related hypertension. METHODS: A total of 72 participants (34 men and 38 women) were enrolled. Comprehensive evaluations were conducted, including cardiac autonomic function assessments, body composition estimation and biochemical analysis. Participants were categorized as CAD-positive or CAD-negative based on Ewing's criteria for autonomic dysfunction. Univariate logistic regression analysis was performed to identify potential predictors for CAD. Multivariate logistic regression models were further constructed by adjusting clinically relevant covariates to identify independent predictors of CAD. RESULTS: Multivariate logistic regression analysis revealed that resting heart rate (HRrest), (odds ratio, confidence interval: 0.85, 0.78-0.93; p = 0.001) and percentage body fat (BF%), (odds ratio, confidence interval: 0.78, 0.64-0.96; p = 0.018) were significant independent predictors of CAD. Receiver Operating Characteristic curve analysis depicted optimal cut-off values for HRrest and BF% as > 74.1 bpm and > 33.6%, respectively. Multicolinearity analysis showed variance inflation factors (VIF) below the cautionary threshold of 3. CONCLUSIONS: The HRrest and BF% emerged as significant independent predictors of CAD in obesity-related hypertension. Therapeutic strategies should target HRrest < 74.1 bpm and BF% < 33.6% to mitigate CAD risk in this population. Future trials are required to establish causal relationships and may consider additional confounding variables in obesity-related hypertension.

The ongoing impact of obesity on childhood hypertension.

Obesity rates among children have been steadily rising over the past several decades. This epidemic has been accompanied by an increase in the prevalence of childhood hypertension, with children in low- and middle-income countries being affected to the same extent as children in high-income countries. This review will examine the trends in childhood blood pressure and the relationship between excess body weight and the development of hypertension. In addition, distinct mechanisms of obesity-related hypertension will be discussed. There will be an emphasis on recent studies conducted since the publication of new guidelines by the American Academy of Pediatrics in 2017 which resulted in the adoption of lower normative blood pressure cutoffs. The overall intent of this review is to provide the reader with an understanding of the ongoing impact, and complexities, of obesity-related hypertension.

Adrenomedullin Improves Hypertension and Vascular Remodeling partly through the Receptor-Mediated AMPK Pathway in Rats with Obesity-Related Hypertension.

Adrenomedullin (ADM) is a novel cardiovascular peptide with anti-inflammatory and antioxidant properties. Chronic inflammation, oxidative stress and calcification play pivotal roles in the pathogenesis of vascular dysfunction in obesity-related hypertension (OH). Our study aimed to explore the effects of ADM on the vascular inflammation, oxidative stress and calcification in rats with OH. Eight-week-old Sprague Dawley male rats were fed with either a Control diet or a high fat diet (HFD) for 28 weeks. Next, the OH rats were randomly subdivided into two groups as follows: (1) HFD control group, and (2) HFD with ADM. A 4-week treatment with ADM (7.2 µg/kg/day, ip) not only improved hypertension and vascular remodeling, but also inhibited vascular inflammation, oxidative stress and calcification in aorta of rats with OH. In vitro experiments, ADM (10 nM) in A7r5 cells (rat thoracic aorta smooth muscle cells) attenuated palmitic acid (PA, 200 µM) or angiotensin II (Ang II, 10 nM) alone or their combination treatment-induced inflammation, oxidative stress and calcification, which were effectively inhibited by the ADM receptor antagonist ADM22-52 and AMP-activated protein kinase (AMPK) inhibitor Compound C, respectively. Moreover, ADM treatment significantly inhibited Ang II type 1 receptor (AT1R) protein expression in aorta of rats with OH or in PA-treated A7r5 cells. ADM improved hypertension, vascular remodeling and arterial stiffness, and attenuated inflammation, oxidative stress and calcification in OH state partially via receptor-mediated AMPK pathway. The results also raise the possibility that ADM will be considered for improving hypertension and vascular damage in patients with OH.

The prevalence of obesity-related hypertension among middle-aged and older adults in China.

Objective: The aim of our study was to assess the prevalence and geographic variation of obesity-related hypertension in China among adults aged 45 years or older. Methods: Data were derived from the China Health and Retirement Longitudinal Study (CHARLS) conducted in 2015. Stratified sample households covered 150 counties/districts and 450 villages/urban communities from 28 provinces by using household questionnaires, clinical measurements, and blood-based bioassays. A multivariable non-conditional logistic regression model was used to analyze the risk factors correlated with obesity-related hypertension. Results: The prevalence of obesity-related hypertension was 22.7%, ~120 million people, among adults aged 45 years or older in China. For people in the age ranges of 45-54, 55-64, 65-74, and ≥75 years, the prevalence of obesity-related hypertension was 16.7, 24.3, 27, and 26.7%, respectively, and the prevalence of obesity-related hypertension among hypertensive participants was 66.0, 60.9, 54.2, and 47.3%, respectively. Compared with non-obesity-related hypertension, the obesity-related hypertensive patients had a higher prevalence of diabetes mellitus, dyslipidemia, and hyperuricemia (all P < 0.0001). The prevalence of obesity-related hypertension showed a decreasing gradient from north to south and from east to west. Multivariate logistic regression analysis showed that female gender, living in urban areas, diabetes mellitus, dyslipidemia, and hyperuricemia were positively correlated with obesity-related hypertension. Conclusion: The prevalence of obesity-related hypertension among adults aged 45 years or older was high in China. Among hypertensive participants, older age was negatively correlated with obesity-related hypertension. Obesity-related hypertensive participants are more prone to aggregation of risk factors of atherosclerotic cardiovascular disease.

Adrenomedullin Improves Cardiac Remodeling and Function in Obese Rats with Hypertension.

This study aimed to determine whether adrenomedullin (ADM, 7.2 µg/kg/day, ip), an important endogenous active peptide, has a protective role in cardiac remodeling and function in obesity-related hypertension (OH) rats. A high-fat diet (HFD) was used to induce OH for 20 weeks. H9c2 cells incubated with palmitate (PA, 200 µM) to mimic high free fatty acid in obesity were used as an in vitro model. In OH rats, ADM not only decreased body weight (BW) and blood pressure (BP) but also improved systemic inflammation and oxidative stress. Moreover, ADM still had a greater inhibitory effect on local inflammation and oxidative stress in the hearts of OH rats, and the same anti-inflammatory and antioxidant effects were also confirmed in PA-treated H9c2 cells. The ADM receptor antagonist or Akt inhibitor effectively attenuated the inhibitory effects of ADM on inflammation and oxidative stress in PA-stimulated H9c2 cells. Furthermore, ADM application effectively normalized heart function, and hematoxylin-eosin and Masson staining and collagen volume fraction results showed that ADM improved cardiac remodeling in hearts of OH rats. ADM attenuated cardiac inflammation and oxidative stress via the receptor-Akt pathway, which involves the improvement of cardiac remodeling and function in OH rats.

Research progress of miR-200 family and obesity-related hypertension / 公共卫生与预防医学

Obesity-related hypertension is a common hypertension as well as a common chronic disease with wide distribution and great harm to human health. In recent years, this disease has become one of the hot issues of public health due to the significant increase in prevalence. The pathogenesis and pathway of obesity-related hypertension are not yet clear, and the research on its pathogenesis has received extensive attention. Studies have shown that they are regulated in most biological processes, including differentiation, proliferation, migration, and apoptosis. The miR-200 family is a group of miRNAs, which have been suggested to play a crucial role in obesity-related hypertension and glucolipid metabolism dysfunction in recent years. This paper reviews relevant research results, suggesting that the expression level of miR-200 family in obese patients with hypertension is higher than that in healthy people, which regulates the occurrence and development of hypertension through mediating oxidative stress response and GATA expression level. This review reveals the relationship between miR-200 family and obesity-related hypertension, which offers new clues to explore potential therapeutic targets for obesity-related hypertension.

Effect of Qinggan Zishen Prescription on Metabolic Disorder in Obesity-related Hypertension and Its Mechanism Based on Network Pharmacology / 中国实验方剂学杂志

ObjectiveTo explore the effect of Qinggan Zishen prescription on metabolic disorders in obesity-related hypertension （OBH） patients and analyze the potential pharmacological mechanism based on network pharmacology. MethodA total of 85 eligible OBH patients who were treated in the outpatient or wards of Jiangsu Province Hospital of Chinese medicine from September 2018 to January 2020 were selected and randomized into the observation group （45 cases） and control group （40 cases）. All patients were treated with western medicine during a four-week introduction period， and then the observation group was treated with Qinggan Zishen prescription on the basis of western medicine. The study lasted 6 months， and indicators， such as triglycerides （TG）， total cholesterol （TC）， high-density lipoprotein cholesterol （HDL-C）， low-density lipoprotein cholesterol （LDL-C）， glycosylated hemoglobin （HbA1c）， fasting blood glucose （FBG）， fasting insulin （FINS）， waist circumference （W）， hip circumference （H） were detected and homeostasis model assessment of insulin resistance （HOMA-IR），body mass index （BMI）， waist-hip ratio （WHR） were calculated before and after intervention. At the same time， the regulation network of the Qinggan Zishen prescription was visualized and the protein-protein interaction （PPI） network was constructed. The core targets of the network were obtained for Gene Ontology （GO） term enrichment and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analysis. ResultAfter intervention for 6 months， the levels of W， H， WHR， FINS， and HOMA-IR in the observation group were reduced as compared with those in the control group （P<0.05， P<0.01）. According to network pharmacology， the main components of Qinggan Zishen prescription in treating OBH were luteolin， quercetin， and berberine and the key targets were amyloid precursor protein （APP）， vascular endothelial growth factor A （VEGFA）， and estrogen receptor 1 （ESR1）. Moreover， the key biological pathway was advanced glycation end product （AGE）/advanced glycation end product receptor （RAGE） signaling pathway. ConclusionQinggan Zishen prescription can improve the metabolic disorder of OBH patients through multiple components， multiple targets， and multiple pathways， which provides new mindset for follow-up studies.

Renal NKCC2 Is Dual Regulated by the Synergy of 20-HETE and High-Fat Diet in CYP4F2 Transgenic Mice.

INTRODUCTION: 20-Hydroxyeicosatetraenoic acid (20-HETE) is the metabolite of cytochrome P450, which modulates blood pressure by inhibiting renal sodium transport. However, the molecular mechanisms underlying the role of 20-HETE in the development of obesity-related hypertension remain unclear, necessitating this study. METHODS: Cytochrome P450 4F2 (CYP4F2) transgenic mice fed high-fat diet (HFD) were used as research animal models. The expression of renal ion transport molecules targeted by 20-HETE was evaluated by real-time PCR and Western blot (WB). The regulatory effect of 20-HETE and HFD on renal Na+-K+-2Cl- cotransporter, isoform 2 (NKCC2) was explored by immunoprecipitation, WB, and luciferase assay. RESULTS: A 2-week HFD feeding dramatically decreased protein abundance but increased renal NKCC2 mRNA expression in CYP4F2 transgenic mice. The decrease in NKCC2 protein was demonstrated to be due to ubiquitination induced by the synergy between 20-HETE and HFD. The increased PPAR-γ protein in CYP4F2 transgenic mice fed HFD and the activation of rosiglitazone on the luciferase reporter construct of the NKCC2 promoter demonstrated that the increase in NKCC2 mRNA in CYP4F2 transgenic mice fed HFD was a consequence of elevated PPAR-γ protein induced by the synergy between 20-HETE and HFD. CONCLUSIONS: Our data demonstrated that the synergy between 20-HETE and HFD could decrease NKCC2 protein via posttranslational ubiquitination, which was thought to be the main mechanism underlying the short-term effect in response to HFD and might be responsible for the adaptive modulation of renal NKCC2 to resist sodium retention. Moreover, the increased NKCC2 mRNA expression via PPAR-γ-induced transcriptional regulation was thought to be the main mechanism underlying the long-term effect in response to HFD and plays a pivotal role in the development of obesity-related hypertension.

Obesity, metabolic syndrome, and primary hypertension.

Primary hypertension is the dominant form of arterial hypertension in adolescents. Disturbed body composition with, among other things, increased visceral fat deposition, accelerated biological maturation, metabolic abnormalities typical for metabolic syndrome, and increased adrenergic drive constitutes the intermediary phenotype of primary hypertension. Metabolic syndrome is observed in 15-20% of adolescents with primary hypertension. These features are also typical of obesity-related hypertension. Metabolic abnormalities and metabolic syndrome are closely associated with both the severity of hypertension and the risk of target organ damage. However, even though increased body mass index is the main determinant of blood pressure in the general population, not every hypertensive adolescent is obese and not every obese patient suffers from hypertension or metabolic abnormalities typical for metabolic syndrome. Thus, the concepts of metabolically healthy obesity, normal weight metabolically unhealthy, and metabolically unhealthy obese phenotypes have been developed. The risk of hypertension and hypertensive target organ damage increases with exposure to metabolic risk factors which are determined by disturbed body composition and visceral obesity. Due to the fact that both primary hypertension and obesity-related hypertension present similar pathogenesis, the principles of treatment are the same and are focused not only on lowering blood pressure, but also on normalizing body composition and metabolic abnormalities.

Banxia Baizhu Tianma decoction attenuates obesity-related hypertension.

ETHNOPHARMACOLOGICAL RELEVANCE: Banxia Baizhu Tianma decoction (BBTD) is a classical representative prescription for expelling phlegm, extinguishing wind, strengthening the spleen and dissipating excessive fluid in traditional Chinese medicine (TCM). According to both TCM theory and about 300 years of clinical practice, BBTD is especially suitable for hypertensive patients of abdominal obesity and lacking physical activity. AIM OF THE STUDY: The present study tried to interpret the pharmacology of the ancient formula of BBTD. Herein, we focused on the plasma metabonomics of BBTD and evaluated the effect and targets of BBTD on endothelial protective effect. METHODS: Obesity-related hypertensive mice were induced by high-fat diet for 20 weeks. BBTD (17.8 g/kg) was administered intragastrically for 8 weeks, and telmisartan group (12.5 mg/kg) was used as positive drug. Body weight, blood pressure, triglyceride and cholesterol were recorded to evaluate the efficacy of BBTD in vivo. Lipid deposition in aortic roots was assessed by oil red O staining, while morphology of aortas was observed by HE staining. Ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) was performed to study the plasma non-targeted metabonomics. According to the data of metabonomics, human aortic endothelial cells (HAECs) were treated by oxidized low-density lipoprotein (ox-LDL, 50 µg/mL) with/without BBTD (2, 1 or 0.5 mg/mL). Apoptosis rate (Annexin V-FITC/PI), migration (Transwell), cytoskeleton (Phalloidin) and density of VE-cadherin (Immunofluorescence staining) were used to investigate the effect of BBTD in vitro. Transcriptome sequencing was performed (2 mg/mL BBTD vs ox-LDL) to screen the possible targets of BBTD in endothelial protection against ox-LDL. RESULTS: BBTD effectively reduced the body weight and total cholesterol, and decreased 12.1 mmHg in SBP and 10.5 mmHg in DBP of obesity-related hypertensive mice (P < 0.05). BBTD attenuated lipid deposition in arterial roots and improved the morphology of aortas in vivo. Plasma metabolite profiles identified 94 differential metabolites and suggested BBTD mainly affected glycerophospholipids and fatty acyls. Bioinformatics analysis indicated sphingolipid metabolism and fluid shear stress and atherosclerosis were main pathways. Therefore, we focused on endothelial protective effect of BBTD against ox-LDL. In vitro, BBTD demonstrated endothelial protective effects, decreasing apoptosis rate, improving cell migration in dose-dependent manner and maintaining cell morphology. Transcriptome sequencing identified 251 downregulated and 603 upregulated mRNAs after 24h-BBTD treatment, which reversed 51.8% change in mRNAs (393 DE mRNAs) induced by ox-LDL. Bioinformatics analysis supported the potential of BBTD in hypertension and suggested that BBTD improved endothelial cells by targeting mainly on p53 and PPAR signaling pathways. CONCLUSIONS: BBTD attenuates obesity-related hypertension by regulating metabolism of glycerophospholipids and endothelial protection.

Intermedin in Paraventricular Nucleus Attenuates Ang II-Induced Sympathoexcitation through the Inhibition of NADPH Oxidase-Dependent ROS Generation in Obese Rats with Hypertension.

Increased reactive oxygen species (ROS) induced by angiotensin II (Ang II) in the paraventricular nucleus (PVN) play a critical role in sympathetic overdrive in hypertension (OH). Intermedin (IMD), a bioactive peptide, has extensive clinically prospects in preventing and treating cardiovascular diseases. The study was designed to test the hypothesis that IMD in the PVN can inhibit the generation of ROS caused by Ang II for attenuating sympathetic nerve activity (SNA) and blood pressure (BP) in rats with obesity-related hypertension (OH). Male Sprague-Dawley rats (160-180 g) were used to induce OH by feeding of a high-fat diet (42% kcal as fat) for 12 weeks. The dynamic changes of sympathetic outflow were evaluated as the alterations of renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) responses to certain chemicals. The results showed that the protein expressions of Ang II type 1 receptor (AT1R), calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein 2 (RAMP2) and RAMP3 were markedly increased, but IMD was much lower in OH rats when compared to control rats. IMD itself microinjection into PVN not only lowered SNA, NADPH oxidase activity and ROS level, but also decreased Ang II-caused sympathetic overdrive, and increased NADPH oxidase activity, ROS levels and mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) activation in OH rats. However, those effects were mostly blocked by the adrenomedullin (AM) receptor antagonist AM22-52 pretreatment. The enhancement of SNA caused by Ang II can be significantly attenuated by the pretreatment of AT1R antagonist lorsatan, superoxide scavenger Tempol and NADPH oxidase inhibitor apocynin (Apo) in OH rats. ERK activation inhibitor U0126 in the PVN reversed Ang II-induced enhancement of SNA, and Apo and IMD pretreatment in the PVN decreased Ang II-induced ERK activation. Chronic IMD administration in the PVN resulted in significant reductions in basal SNA and BP in OH rats. Moreover, IMD lowered NADPH oxidase activity and ROS level in the PVN; reduced the protein expressions of AT1R and NADPH oxidase subunits NOX2 and NOX4, and ERK activation in the PVN; and decreased Ang II levels-inducing sympathetic overactivation. These results indicated that IMD via AM receptors in the PVN attenuates SNA and hypertension, and decreases Ang II-induced enhancement of SNA through the inhibition of NADPH oxidase activity and ERK activation.

Downregulation of Orexin Receptor in Hypothalamic Paraventricular Nucleus Decreases Blood Pressure in Obese Zucker Rats.

Background Orexin and its receptors are critical regulating sympathetic vasomotor tone under physiological and pathophysiological conditions. Orexin receptor 1 ( OXR 1) is upregulated in the paraventricular nucleus ( PVN ) in the hypothalamus and contributes to increased sympathetic outflow in obese Zucker rats ( OZR s). We hypothesized that silencing OXR 1 expression in the PVN decreases heightened blood pressure and elevated sympathetic outflow in OZR s. Methods and Results An adeno-associated virus ( AAV ) vector containing a short hairpin RNA (sh RNA ) targeting rat OXR 1 was designed to silence OXR 1 expression in the PVN . The AAV - OXR 1-sh RNA or scrambled sh RNA was injected into the PVN in OZR s. The arterial blood pressure in free-moving OZR s was continuously monitored by using a telemetry approach. The firing activity of spinally projecting PVN neurons in rat brain slices was recorded 3 to 4 weeks after injection of viral vectors. The free-moving OZR s treated with AAV - OXR 1-sh RNA had markedly lower OXR 1 expression and lower mean arterial blood pressure, heart rate, and ratio of low- to high-frequency components of heart rate variability compared with OZR s treated with scrambled sh RNA . Furthermore, AAV - OXR 1-sh RNA treatment markedly reduced renal sympathetic nerve activity and attenuated sympathoexcitatory response induced by microinjection of orexin A into the PVN . In addition, treatment with AAV - OXR 1-sh RNA substantially decreased the basal firing activity of spinally projecting PVN neurons in OZR s and attenuated the excitatory effect of orexin A on the firing activity of these neurons. Conclusions These data suggest that chronic downregulation of OXR 1 expression in the PVN reduces sympathetic vasomotor tone in obesity-related hypertension.

CPI-17-mediated contraction of vascular smooth muscle is essential for the development of hypertension in obese mice.

Several factors have been implicated in obesity-related hypertension, but the genesis of the hypertension is largely unknown. In this study, we found a significantly upregulated expression of CPI-17 (C-kinase-potentiated protein phosphatase 1 inhibitor of 17 kDa) and protein kinase C (PKC) isoforms in the vascular smooth muscles of high-fat diet (HFD)-fed obese mice. The obese wild-type mice showed a significant elevation of blood pressure and enhanced calcium-sensitized contraction of vascular smooth muscles. However, the obese CPI-17-deficient mice showed a normotensive blood pressure, and the calcium-sensitized contraction was consistently reduced. In addition, the mutant muscle displayed an abolished responsive force to a PKC activator and a 30%-50% reduction in both the initial peak force and sustained force in response to various G protein-coupled receptor (GPCR) agonists. Our observations showed that CPI-17-mediated calcium sensitization is mediated through a GPCR/PKC/CPI-17/MLCP/RLC signaling pathway. We therefore propose that the upregulation of CPI-17-mediated calcium-sensitized vasocontraction by obesity contributes to the development of obesity-related hypertension.

Intermedin in Paraventricular Nucleus Attenuates Sympathoexcitation and Decreases TLR4-Mediated Sympathetic Activation via Adrenomedullin Receptors in Rats with Obesity-Related Hypertension.

Intermedin/adrenomedullin-2 (IMD/AM2), a member of the calcitonin gene-related peptide/AM family, plays an important role in protecting the cardiovascular system. However, its role in the enhanced sympathoexcitation in obesity-related hypertension is unknown. In this study, we investigated the effects of IMD in the paraventricular nucleus (PVN) of the hypothalamus on sympathetic nerve activity (SNA), and lipopolysaccharide (LPS)-induced sympathetic activation in obesity-related hypertensive (OH) rats induced by a high-fat diet for 12 weeks. Acute experiments were performed under anesthesia. The dynamic alterations of sympathetic outflow were evaluated as changes in renal SNA and mean arterial pressure (MAP) in response to specific drugs. Male rats were fed a control diet (12% kcal as fat) or a high-fat diet (42% kcal as fat) for 12 weeks to induce OH. The results showed that IMD protein in the PVN was downregulated, but Toll-like receptor 4 (TLR4) and plasma norepinephrine (NE, indicating sympathetic hyperactivity) levels, and systolic blood pressure were increased in OH rats. LPS (0.5 µg/50 nL)-induced enhancement of renal SNA and MAP was greater in OH rats than in obese or control rats. Bilateral PVN microinjection of IMD (50 pmol) caused greater decreases in renal SNA and MAP in OH rats than in control rats, and inhibited LPS-induced sympathetic activation, and these were effectively prevented in OH rats by pretreatment with the AM receptor antagonist AM22-52. The mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) inhibitor U0126 in the PVN partially reversed the LPS-induced enhancement of SNA. However, IMD in the PVN decreased the LPS-induced ERK activation, which was also effectively prevented by AM22-52. Chronic IMD administration resulted in significant reductions in the plasma NE level and blood pressure in OH rats. Moreover, IMD lowered the TLR4 protein expression and ERK activation in the PVN, and decreased the LPS-induced sympathetic overactivity. These results indicate that IMD in the PVN attenuates SNA and hypertension, and decreases the ERK activation implicated in the LPS-induced enhancement of SNA in OH rats, and this is mediated by AM receptors.

Intermedin in Paraventricular Nucleus Attenuates Sympathoexcitation and Decreases TLR4-Mediated Sympathetic Activation via Adrenomedullin Receptors in Rats with Obesity-Related Hypertension / 神经科学通报·英文版

Intermedin/adrenomedullin-2 (IMD/AM2), a member of the calcitonin gene-related peptide/AM family, plays an important role in protecting the cardiovascular system. However, its role in the enhanced sympathoexcitation in obesity-related hypertension is unknown. In this study, we investigated the effects of IMD in the paraventricular nucleus (PVN) of the hypothalamus on sympathetic nerve activity (SNA), and lipopolysaccharide (LPS)-induced sympathetic activation in obesity-related hypertensive (OH) rats induced by a high-fat diet for 12 weeks. Acute experiments were performed under anesthesia. The dynamic alterations of sympathetic outflow were evaluated as changes in renal SNA and mean arterial pressure (MAP) in response to specific drugs. Male rats were fed a control diet (12% kcal as fat) or a high-fat diet (42% kcal as fat) for 12 weeks to induce OH. The results showed that IMD protein in the PVN was downregulated, but Toll-like receptor 4 (TLR4) and plasma norepinephrine (NE, indicating sympathetic hyperactivity) levels, and systolic blood pressure were increased in OH rats. LPS (0.5 µg/50 nL)-induced enhancement of renal SNA and MAP was greater in OH rats than in obese or control rats. Bilateral PVN microinjection of IMD (50 pmol) caused greater decreases in renal SNA and MAP in OH rats than in control rats, and inhibited LPS-induced sympathetic activation, and these were effectively prevented in OH rats by pretreatment with the AM receptor antagonist AM22-52. The mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) inhibitor U0126 in the PVN partially reversed the LPS-induced enhancement of SNA. However, IMD in the PVN decreased the LPS-induced ERK activation, which was also effectively prevented by AM22-52. Chronic IMD administration resulted in significant reductions in the plasma NE level and blood pressure in OH rats. Moreover, IMD lowered the TLR4 protein expression and ERK activation in the PVN, and decreased the LPS-induced sympathetic overactivity. These results indicate that IMD in the PVN attenuates SNA and hypertension, and decreases the ERK activation implicated in the LPS-induced enhancement of SNA in OH rats, and this is mediated by AM receptors.

Obesity and Kidney Disease.

Obesity is a systemic disease of the white adipose tissue, which has evolved into a global epidemic. It is associated with a plethora of adipocyte hormonal (adipokine) imbalances, dysregulation of the energy-balance system, imbalances in metabolic homeostasis, a pro-inflammatory state and multiple target organ damages. Clinically, the obesity phenotype is not homogenous and is more likely to represent a spectrum with varying degrees of metabolic un-health; metabolically-unhealthy obesity is often a part of the metabolic syndrome. The links between obesity and chronic kidney disease are numerous, bidirectional, multi-layered and complex; this complexity may be explained by shared pathophysiological pathways (e.g. chronic inflammation, increased oxidative stress, and hyper-insulinemia), shared clusters of risk factors as well as associated diseases (e.g. insulin resistance, hypertension and dyslipidemia). We will review these links and their clinical manifestations, and offer a summary of available non-pharmacological as well as pharmacological therapeutic strategies.

Pharmacotherapeutic strategies for treating hypertension in patients with obesity.

INTRODUCTION: Hypertension and obesity are important health challenges that independently increase cardiovascular morbidity and mortality. There is a lack of randomized controlled trials to clearly inform on preferred drug choices to be adopted in clinical practice for the treatment of obesity-related hypertension (OHT). Adequate differentiation of drug classes for preferential use in obesity or the metabolic syndrome aimed at avoiding adverse effects on body weight and the metabolic profile is neglected in this population, at least in part due to the lack of specific pharmacologic recommendations in hypertension guidelines. AREAS COVERED: The authors summarize and suggest pharmacotherapeutic strategies based on pathophysiologic rationale to achieve blood pressure (BP) control and avoid adverse metabolic consequences in OHT. EXPERT OPINION: Combinations of various pharmacologic antihypertensive approaches are required in the management of OHT. It is recommended that targeting sympathetic overactivity with a centrally acting sympatholytic agent such as moxonidine should be considered as a preferred second line treatment choice in combination with renin angiotensin system (RAS) blockade, the current first line choice. Though not all obese subjects have sympathetic overdrive, this approach is likely to provide effective control of blood pressure and improve the metabolic profile of patients with OHT along with positive implications for cardiovascular risk reduction.

The Role of Sympatho-Inhibition in Combination Treatment of Obesity-Related Hypertension.

Obesity-related hypertension is commonly characterized by increased sympathetic nerve activity and is therefore acknowledged as a predominantly neurogenic form of hypertension. The sustained sympatho-excitation not only contributes to the rise in blood pressure but also elicits a vicious cycle which facilitates further weight gain and progression of associated co-morbidities. While weight loss and exercise remain at the forefront of therapy for obesity and obesity-related hypertension, the difficulties in achieving and maintaining long-term weight loss with lifestyle measures and the variable blood pressure response to weight loss often necessitate prescription of antihypertensive drug therapy. Remarkably, there are no specific recommendations for pharmacologic treatment for obese patients with arterial hypertension in any of the current guidelines and general principles of antihypertensive treatment are applied. The use of ß-blockers and diuretics is commonly discouraged as first- or second-line therapy due to their unfavorable metabolic effects. This review explores evolving therapeutic strategies which based on their interference with pathophysiologic mechanism relevant in the context of obesity may guide optimized treatment of obesity-related hypertension.

Pharmacodynamic and pharmacological effect of Tribulus terrestris on kidney of rats with obesity-related hypertension through leptin mediated JAK2/STAT3 pathway / 中草药

Objective: To observe the effect and explore the mechanism of Tribulus terrestris (TT) on kidney of rats with obesity-related hypertension through leptin mediated JAK2/STAT3 pathway. Methods: To establish the model of rats with obesity-related hypertension by high-fat diet. The model rats were randomly divided into three groups: TT group (eight rats, 17.2 g/kg), Telmisartan group (eight rats, 3.4 mg/kg), and model group (eight rats, normal saline 2 mL/d). Rats were ig given drugs or saline for 12 weeks. The body weights and blood pressure were measured regularly. At the end of the study, the rats were sacrificed and the levels of serum lipid and angiotensinII (AngII) and β2-microglobulin (β2-MG) were determined by ELISA. Morphological changes of adipose tissue and kidney were observed by HE staining. The density of LepR in kidney was observed by immunohistochemical staining. Levels of mRNA and protein expression of JAK2 and STAT3 in kidney were determined by quantitive real-time PCR (qRT-PCR) and Western blotting. Results: Both body weights and blood pressure of TT group were decreased (P < 0.05). The levels of serum TG, TC, and LDL-C of TT group were decreased significantly (P < 0.05). Kidney morphology of TT group was improved obviously and the size of lipocyte decreased. The levels of serum Ang II, Lep, and β2-MG of TT group decreased significantly (P < 0.05). The density of LepR in kidney of TT group decreased significantly (P < 0.05). The mRNA and protein expression of JAK2 and STAT3 in kidney of TT group was decreased significantly (P < 0.05). Conclusion: TT improves the leptin resistance of the obesity-related hypertensive rats mainly through JAK2/STAT3 pathway.