Hyperactivity Of Sympathetic Nervous System Research Articles

RGS4 Mediates Catecholaminergic Inhibition of Short‐Chain Fatty Acid Receptor FFAR3 Signaling & Function in Cardiomyocytes

BackgroundFree fatty acids (FFAs) are essential cell nutrients but also important signaling molecules regulating various cellular processes. Short‐chain fatty acids (SCFAs), like propionate and butyrate, activate two different types of G protein‐coupled receptors (GPCRs), FFAR2 and FFAR3. FFAR3 (also known as GPR41) couples to Gi/o proteins lowering cyclic 3’,5’‐adenosine monophosphate (cAMP) levels and activating mitogen‐activated protein kinases (MAPKs). In addition to adipose tissue, FFAR3 is highly expressed in peripheral sympathetic ganglia augmenting sympathetic nervous system (SNS) outflow. Regulator of G protein Signaling (RGS)‐4 belongs to the RGS superfamily of proteins and inactivates (terminates) both Gi/o‐ and Gq‐protein signaling. Cardiac RGS4 has been implicated in atrial fibrillation (AFib) prevention via calcium signaling attenuation. Finally, β‐adrenergic receptors (ARs), the major mediators of catecholaminergic and SNS actions in cardiac myocytes, stimulate cAMP synthesis and activate protein kinase A (PKA), which is known to activate RGS4 via phosphorylation.Study objectiveSince catecholamines/SNS and RGS4 play major roles in AFib pathophysiology and FFAR3 promotes SNS activity, we examined whether RGS4 regulates cardiac FFAR3 signaling.MethodsWe used H9c2 cardiomyocytes transfected to express the human FFAR3. After treatment with catecholaminergic agonists and/or propionic acid plus various pharmacological inhibitors and siRNA to deplete RGS4, we performed signaling assays (western blotting, cAMP accumulation, GTP binding, ELISA) to delineate the precise involvement of RGS4 in the cardiac βAR‐FFAR3 signaling crosstalk.ResultsRGS4 is essential for the dampening of propionate/FFAR3‐dependent signaling in H9c2 cardiomyocytes since siRNA‐mediated RGS4 depletion significantly enhances the effect of propionic acid on cAMP lowering, Gi/o activation, and p38 MAPK activation. Notably, concomitant isoproterenol or salbutamol treatment blocks propionic acid‐induced signaling via the FFAR3 in H9c2 cardiomyocytes, indicating negative regulation of FFAR3 by catecholamines via the β2AR. Mechanistically, this is mediated by RGS4, since neither isoproterenol, nor salbutamol can inhibit propionate signaling upon siRNA‐mediated RGS4 depletion. Finally, this β2AR trans‐inhibition of FFAR3 signaling via RGS4 is dependent on β2AR‐activated PKA, because pre‐treatment with the PKA inhibitor H89 abrogated the catecholaminergic inhibition of FFAR3 signaling (cAMP lowering, downstream p38 MAPK activation, interleukin (IL)‐6 production) in H9c2 cardiomyocytes.Conclusionsβ2AR‐activated RGS4 abrogates SCFA/FFAR3 signaling and function in cardiac myocytes. This may represent part of the mechanism via which RGS4 protects against both AFib pathogenesis and FFAR3‐promoted SNS hyperactivity and inflammation in the myocardium.

Five-Year PTSD Symptom Remission in Two Patients Following Treatment With Rivastigmine.

The beneficial effect of rivastigmine, an acetylcholinesterase inhibitor (AChEi), which increases levels of acetylcholine (ACh), was first reported in 2013. This paper replicates those findings and reports sustained symptom remission. The high-frequency (HF) component of heart rate variability (HRV) is a measure of cholinergic withdrawal and was measured using a Zephyr Bioharness HR monitor, pre- and post-commencement of treatment. Data analysis was performed using Kubios HRV software. PTSD symptom severity was assessed using the Post-Traumatic Checklist-Civilian (PCL-C). Low HF HRV was observed in both patients before rivastigmine treatment and reductions in PCL-C scores paralleled increases in HF HRV values. Follow-up revealed low HF HRV values in both patients despite PCL-C scores indicating remission. Sympathetic nervous system hyperactivity was observed in one patient, just before a suicide attempt. Following rivastigmine treatment, the patient had no further suicidal ideation or attempts. Another patient reported worsening of her PTSD symptoms in the peri-menstrual period, which was abolished by rivastigmine. She also experienced symptom relapse following prolonged infections. Low HF HRV has been reported in PTSD patients, but findings have been inconsistent. Cholinergic withdrawal could explain the disturbances in sleep, learning, and memory seen in PTSD patients. The relapse of symptoms following prolonged infection implicates the immune system as a possible initiator of the disorder. ACh and estrogen have anti-inflammatory properties, supporting a possible role of inflammation in initiating PTSD. The effect of rivastigmine treatment should be tested in properly controlled clinical trials.

Effectiveness of radiofrequency renal denervation in diseases with increased sympathetic nervous system activity

The article discusses the role of sympathetic nervous system hyperactivity in the pathogenesis of various pathologies (hypertension, heart failure, atrial fibrillation, metabolic syndrome, diabetes and systemic inflammatory response syndrome). On the example of large randomized clinical trials using catheter-based radiofrequency ablation, the antihypertensive effect in patients with uncontrolled hypertension has been proven. The first experimental and clinical studies on the effectiveness of renal denervation in reducing the activity of inflammatory markers, the incidence of atrial fibrillation and ventricular arrhythmia episodes, and improving the left ventricular contractility. The first clinical results of the favorable effect of renal denervation on carbohydrate metabolism (insulin resistance and glycemic level) in patients with metabolic syndrome and diabetes have been studied in detail.

Effects of Intermittent Hypoxia on Cytokine Expression Involved in Insulin Resistance.

Sleep apnea syndrome (SAS) is a prevalent disorder characterized by recurrent apnea or hypoxia episodes leading to intermittent hypoxia (IH) and arousals during sleep. Currently, the relationship between SAS and metabolic diseases is being actively analyzed, and SAS is considered to be an independent risk factor for the development and progression of insulin resistance/type 2 diabetes (T2DM). Accumulating evidence suggests that the short cycles of decreased oxygen saturation and rapid reoxygenation, a typical feature of SAS, contribute to the development of glucose intolerance and insulin resistance. In addition to IH, several pathological conditions may also contribute to insulin resistance, including sympathetic nervous system hyperactivity, oxidative stress, vascular endothelial dysfunction, and the activation of inflammatory cytokines. However, the detailed mechanism by which IH induces insulin resistance in SAS patients has not been fully revealed. We have previously reported that IH stress may exacerbate insulin resistance/T2DM, especially in hepatocytes, adipocytes, and skeletal muscle cells, by causing abnormal cytokine expression/secretion from each cell. Adipose tissues, skeletal muscle, and the liver are the main endocrine organs producing hepatokines, adipokines, and myokines, respectively. In this review, we focus on the effect of IH on hepatokine, adipokine, and myokine expression.

Catestatin as a Biomarker of Cardiovascular Diseases: A Clinical Perspective.

Accounting for almost one-third of the global mortality, cardiovascular diseases (CVDs) represent a major global health issue. Emerging data suggest that most of the well-established mechanistic explanations regarding the cardiovascular pathophysiology are flawed, and cannot fully explain the progression and long-term effects of these diseases. On the other hand, dysregulation of the sympathetic nervous system (SNS) has emerged as an important player in the pathophysiology of CVDs. Even though upregulated SNS activity is an essential compensatory response to various stress conditions, in the long term, it becomes a major contributor to both cardiac dysfunction and vascular damage. Despite the fact that the importance of SNS hyperactivity in the setting of CVDs has been well-appreciated, its exact quantification and clinical application in either diagnostics or therapy of CVDs is still out of reach. Nevertheless, in recent years a number of novel laboratory biomarkers implicated in the pathophysiology of SNS activation have been explored. Specifically, in this review, we aimed to discuss the role of catestatin, a potent physiological inhibitor of catecholamine spillover that offers cardioprotective effects. Limited data indicate that catestatin could also be a reliable indirect marker of SNS activity and it is likely that high CST levels reflect advanced CV disease burden. Consequently, large-scale studies are required to validate these observations in the upcoming future.

Endothelial NADPH oxidases protect against sympathetic nervous system hyperactivity-induced cardiac dysfunction and remodeling in mice: contribution of SGLT2

Abstract Background NADPH oxidase-derived reactive oxygen species (ROS) contribute to cardiac dysfunction, often characterized by coronary microvascular dysfunction, an inflammatory response and cardiomyocyte hypertrophy. Hyperactivity of the sympathetic nervous system (SNS) induces oxidative stress, promoting cardiac dysfunction and the development of heart failure. Selective inhibitors of sodium-glucose co-transporter 2 (SGLT2), have shown remarkable cardioprotective effects in clinical studies. Recently, SGLT2 inhibitors have been reported to prevent endothelial dysfunction and pro-inflammatory responses in endothelial cells in response to angiotensin II involving NADPH oxidases. Purpose Therefore, the aim of the study was to determine whether endothelial NADPH oxidases promote SNS-induced cardiac dysfunction and to clarify the role of SGLT2. Methods Male wild-type mice and mice lacking the NADPH oxidase subunit p22phox in the endothelium (p22phox ecKO, 11-week-old) were treated with isoproterenol (100 mg/kg) for five consecutive days and sacrificed at day 14. Hemodynamic measurements of left (LV) and right (RV) ventricles were performed by a transthoracic approach. Heart tissue sections were stained with Sirius red to evaluate fibrosis and wheat germ agglutinin to assess cardiomyocyte size. Cultured human microvascular endothelial cells (HMEC-1) were stimulated with 100 nM isoproterenol and ROS levels were assessed by dihydroethidium fluorescence. The expression level of target genes and proteins was assessed by quantitative real-time PCR and Western blot, respectively. siRNA approaches were used to down-regulate either the NADPH oxidase subunit p22phox or SGLT2. Results The isoproterenol treatment increased LV and RV systolic pressures in wild-type mice but not in p22phox ecKO mice. p22phox ecKO mice were protected against isoproterenol-induced fibrosis, cardiac remodeling characterized by upregulation of mRNA levels of ANP, BNP and β-MHC, and pulmonary congestion. LV remodeling was associated with upregulation of the NADPH oxidase subunits p22phox, Nox2, and Nox4 as well as of SGLT2 in wild-type mice, however no such effects were observed in p22phox ecKO mice. Exposure of HMEC-1 to isoproterenol stimulated the formation of ROS and caused an upregulation of p22phox and SGLT2 protein levels in a time- and concentration-dependent manner. No such effects were observed following silencing of either p22phox or SGLT2, or use of a selective SGLT2 inhibitor. Conclusion Deletion of the NADPH oxidase subunit p22phox in the endothelium protected against SNS hyperactivity induced LV cardiac dysfunction and remodeling, and prevented upregulation of SGLT2. Since depletion of SGLT2 prevented the pro-oxidant response to isoproterenol in endothelial cells, the endothelial NADPH oxidase/SGLT2 pathway seems to have a prominent role in promoting cardiac remodeling and dysfunction in SNS hyperactivity. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Deutsches Herzzentrum München

Depleting hypothalamic somatostatinergic neurons recapitulates diabetic phenotypes in mouse brain, bone marrow, adipose and retina.

Hypothalamic inflammation and sympathetic nervous system hyperactivity are hallmark features of the metabolic syndrome and type 2 diabetes. Hypothalamic inflammation may aggravate metabolic and immunological pathologies due to extensive sympathetic activation of peripheral tissues. Loss of somatostatinergic (SST) neurons may contribute to enhanced hypothalamic inflammation. The present data show that leptin receptor-deficient (db/db) mice exhibit reduced hypothalamic SST neurons, particularly in the periventricular nucleus. We model this finding, using adeno-associated virus delivery of diphtheria toxin subunit A (DTA) driven by an SST-cre system to deplete these neurons in Sstcre/gfp mice (SST-DTA). SST-DTA mice exhibit enhanced hypothalamic c-Fos expression and brain inflammation as demonstrated by microglial and astrocytic activation. Bone marrow from SST-DTA mice undergoes skewed haematopoiesis, generating excess granulocyte-monocyte progenitors and increased proinflammatory (C-C chemokine receptor type 2; CCR2hi) monocytes. SST-DTA mice exhibited a 'diabetic retinopathy-like' phenotype: reduced visual function by optokinetic response (0.4 vs 0.25 cycles/degree; SST-DTA vs control mice); delayed electroretinogram oscillatory potentials; and increased percentages of retinal monocytes. Finally, mesenteric visceral adipose tissue from SST-DTA mice was resistant to catecholamine-induced lipolysis, displaying 50% reduction in isoprenaline (isoproterenol)-induced lipolysis compared with control littermates. Importantly, hyperglycaemia was not observed in SST-DTA mice. The isolated reduction in hypothalamic SST neurons was able to recapitulate several hallmark features of type 2 diabetes in disease-relevant tissues.

Dapagliflozin Exerts Adrenal Sympatholysis via G protein-Coupled Receptor Kinase-2 & Tyrosine Hydroxylase Downregulation

Abstract The sodium-glucose co-transporter (SGLT)-2 inhibitor dapagliflozin was recently reported to reduce renal tyrosine hydroxylase (TH) and norepinephrine levels, lowering blood pressure and preventing endothelial dysfunction, in a murine model of neurogenic hypertension. This suggested that dapagliflozin may combat sympathetic nervous system (SNS) hyperactivity, which is known to accompany and aggravate chronic heart failure (CHF). Adrenal G protein-coupled receptor kinase (GRK)-2 upregulation is a major driver of circulating catecholamine (CA) elevation and SNS hyperactivity, especially in CHF. GRK2 severely dysregulates adrenal sympatho-inhibitory α 2-adrenergic receptors (ARs), leading to unchecked, chronically elevated CA secretion. Therefore, we hypothesized herein that SGLT2 inhibition with dapagliflozin may lower SNS hyperactivity in the adrenal gland by antagonizing GRK2 actions on α 2ARs in adrenal chromaffin cells. We used the rat pheochromocytoma PC12 cell line expressing human α 2AAR, as well as freshly isolated adrenal glands from adult male Sprague-Dawley rats treated with dapagliflozin in vivo. We measured circulating norepinephrine (NE) in vivo via RIA, GRK2 & TH expression levels via real-time PCR and immunoblotting, adrenal α 2AR density (Bmax) via saturation radioligand binding with [methyl-3H]-rauwolscine, and G protein activation via the GTPγS assay. Dapagliflozin treatment for 7 consecutive days (20 mg/kg/d in drinking water) led to a significant reduction in blood circulating NE levels (217+67 pg/ml, n=6), compared to control, vehicle-treated rats (363+77 pg/ml, n=6, p<.05), suggesting reduced SNS activity. This was accompanied by reduced GRK2 and TH mRNA and protein levels in dapagliflozin-treated rat adrenals vs. vehicle-treated animal-derived glands, indicating reduced adrenal CA synthesis and secretion. Finally, adrenal α 2AR density was higher in dapagliflozin- vs. vehicle-treated rats (51.3+7.3 vs. 26.1+8.1 fmol/mg of protein, respectively; n=12 glands from 6 animals per group, p<.05). These results (i.e. GRK2 and TH downregulation) were completely recapitulated in PC12 α 2AAR-expressing cells in culture, treated with 5 μM dapagliflozin (or vehicle) for 24 hours. Importantly, α 2AR-dependent G protein-mediated signaling towards inhibition of CA secretion was markedly enhanced at 24 hrs post-dapagliflozin application in PC12 cells. This was the result of reduced GRK2-dependent receptor desensitization, since dapagliflozin lacked this effect in cells co-transfected with a GRK2-encoding adenovirus to acutely overexpress GRK2. In conclusion, dapagliflozin exerts a sympatholytic action in the adrenal medulla via downregulation of both TH, which reduces CA biosynthesis, and GRK2, which reduces α 2AR desensitization in favor of enhanced inhibition of CA secretion.

Metacognition, Stress – Relaxation Balance & Related Hormones

This paper examines the interaction between metacognition and stress response. Specifically, the main purpose of this study is to trace the interaction between metacognition, sympathetic-parasympathetic nervous system and the basic stress-related hormones/neurotransmitters. To achieve this aim, the research seeks to address the following questions: Can metacognition regulate the stress-related hormones and the sympathetic nervous system hyperactivity? How can it contribute to the regulation of uncontrollable stress? What is the role of executive functions? Can metacognition stop the cells and neurons from degeneration and the brain from shrinking? The evidence support the hypothesis that there is a deep relationship between metacognition, stress-related hormones and autonomic nervous system. Therefore, the above finding paves the way for the design of new stress management strategies, which could implemented in family, in school and in workplace. Uncontrollable stress constitutes the “health epidemic” of our century. Mental and mood disorders, premature ageing, cognitive impairments, learning disabilities are some of the stress-related threats. There is an urgent need to focus on resilience in order to cope with stress and to stay in balance.

Low-dose clonidine in veterans with Posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) symptoms of hyperarousal are mediated through sympathetic nervous system hyperactivity. PTSD symptoms, including distressing thoughts and memories, flashbacks, hyperarousal, and sleep disturbances, have been linked with elevated norepinephrine levels in the cerebrospinal fluid. Clonidine, an alpha2-adrenergic agonist, reduces the release of norepinephrine and has been suggested as a treatment for PTSD. However, literature for use of clonidine in PTSD is limited. The objective of this study was to evaluate clinical records of patients with PTSD treated with clonidine to assess reported efficacy and safety. A cohort of veterans with PTSD treated with clonidine at a midwestern VA hospital between July 2015 and January 2018 were studied retrospectively. Medical records of 79 patients with moderate to severe PTSD symptoms were reviewed by three independent clinicians using the Clinical Global Impressions (CGI) scale to quantify symptom severity (CGI-S) before starting clonidine and subjects’ change in symptoms (CGI-I) after starting clonidine. Data on adverse events were also collected. Subgroup analyses were conducted on the impact of comorbid diagnoses, concurrent medications, and substance use. Mean CGI-S score at baseline was 4.8 (5 = markedly ill). After treatment with low-dose clonidine, 72% of patients experienced improvement, and 49% scored “much improved” or “very much improved.” Adverse effects were reported by 18 out of 79 subjects. In this retrospective analysis of veterans prescribed clonidine for PTSD, CGI-I scores suggested improvement in PTSD symptoms, and minimal side effects were reported. In addition, some comorbid diagnoses and concurrent medications were correlated with variations in outcomes.

Abstract 14740: Sympathetic Down-regulation With Zamicastat Reduces Arrhythmogenicity in Isolated Hearts From Rats With Pulmonary Hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a disease often causing right ventricular failure and death. During disease progression, structural and electrical remodeling of the right ventricle creates proarrhythmic substrates and triggers for arrhythmias. Studies of PAH patients show a hyperstimulation of the sympathetic nervous system (SNS) indicating that PAH may be mediated by SNS hyperactivation. Zamicastat (ZAM) is a reversible dopamine β-hydroxylase inhibitor that modulates SNS by reducing the biosynthesis of norepinephrine in peripheral sympathetic nerves. ZAM improves survival in the monocrotaline (MCT) rat model of PAH. Hypothesis: To evaluate the effect of ZAM on electrophysiological parameters in isolated hearts from MCT-treated rats. Methods: Male Wistar Han rats were randomized in 3 groups, Sham (n=6), MCT (n=15) and MCT+ZAM (n=17). On day zero, MCT and MCT+ZAM groups received MCT (60 mg/kg, SC) and Sham group received saline. Starting on day 12, MCT+ZAM rats were daily administered ZAM (30 mg/kg, PO) while all other animals were given vehicle. On day 28, hearts were excised and mounted on a Langendorff system. A bipolar circuit of two electrodes was placed on the epicardium for ECG recording. Provoked arrhythmias were induced with a burst pacing protocol (50Hz, 1 second) and the recovery time was measured as the time needed to reach 3 consecutive stable R-R intervals. Results: MCT increased the proportion of hearts exhibiting bundle branch blocks, 3 rd degree atrioventricular (AV) blocks, atrial fibrillation (AF), ventricular fibrillation (VF) and premature ventricular contractions (PVCs) when compared to Sham group. ZAM treatment suppressed 3 rd degree AV blocks, AF and VF. In addition, PVCs were less frequent in hearts from MCT+ZAM animals as compared to MCT group. Isolated hearts naturally entered a pause following overpacing-induced VF. MCT hearts showed a non-significant 1.7-fold increase in recovery time compared to Sham group. Hearts from MCT+ZAM animals had a significant ≈50% reduction in post-fibrillation pause. Conclusions: These data suggest that treatment with Zamicastat yields a lower proarrhythmic cardiac tissue decreasing the incidence of cardiac arrhythmias.

Extended Renal Artery Denervation Is Associated with Artery Wall Lesions and Acute Systemic and Pulmonary Hemodynamic Changes: A Sham-Controlled Experimental Study.

Objectives We sought to assess acute changes in systemic and pulmonary hemodynamics and microscopic artery lesions following extended renal artery denervation (RDN). Background RDN has been proposed to reduce sympathetic nervous system hyperactivation. Although the effects of RDN on systemic circulation and overall sympathetic activity have been studied, data on the impact of RDN on pulmonary hemodynamics is lacking. Methods The study comprised 13 normotensive Landrace pigs. After randomization, 7 animals were allocated to the group of bilateral RDN and 6 animals to the group of a sham procedure (SHAM). Hemodynamic measures, cannulation, and balloon-based occlusion of the renal arteries were performed in both groups. In the RDN group, radiofrequency ablation was performed in all available arteries and their segments. An autopsy study of the renal arteries was carried out in both groups. Results The analysis was performed on 12 pigs (6 in either group) since pulmonary thromboembolism occurred in one case. A statistically significant drop in the mean diastolic pulmonary artery pressure (PAP) was detected in the RDN group when compared with the SHAM group (change by 13.0 ± 4.4 and 10.0 ± 3.0 mmHg, correspondingly; P = 0.04). In 5 out of 6 pigs in the RDN group, a significant decrease in systemic systolic blood pressure was found, when compared with baseline (98.8 ± 17.8 vs. 90.2 ± 12.6 mmHg, P = 0.04), and a lower mean pulmonary vascular resistance (PVR) (291.0 ± 77.4 vs. 228.5 ± 63.8 dyn∗sec∗cm−5, P = 0.03) after ablation was found. Artery dissections were found in both groups, with prevalence in animals after RDN. Conclusions Extensive RDN leads to a rapid and significant decrease in PAP. In the majority of cases, RDN is associated with an acute lowering of systolic blood pressure and PVR. Extended RDN is associated with artery wall lesions and thrombus formation underdiagnosed by angiography.

Canagliflozin ameliorates renal oxidative stress and inflammation by stimulating AMPK\u2013Akt\u2013eNOS pathway in the isoprenaline-induced oxidative stress model

Diabetes is a leading cause of chronic kidney disease, and the high prevalence of sympathetic nervous system (SNS) hyperactivity in diabetic patients makes them further susceptible to SNS-mediated oxidative stress and accelerated kidney damage. Here, we investigated if canagliflozin can reverse isoprenaline (ISO)-induced renal oxidative damage in rats, a model that mimics SNS overstimulation-induced organ injuries in humans. We found that ISO administration elevates renal oxidative stress markers including malondialdehyde (MDA), advanced protein oxidation product (APOP), myeloperoxidase (MPO) and nitric oxide (NO), while depleting levels of endogenous antioxidants such as catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH). Strikingly, canagliflozin treatment of ISO-treated rats not only prevents elevation of oxidative stress markers but also rescues levels of depleted antioxidants. Our results also show that canagliflozin stimulates antioxidant/anti-inflammatory signaling pathways involving AMP-activated protein kinase (AMPK), Akt and eNOS, and inhibits iNOS and NADPH oxidase isoform 4 (NOX4), all of which are associated with oxidative stress and inflammation. Further, canagliflozin prevents ISO-induced apoptosis of kidney cells by inhibiting Bax protein upregulation and caspase-3 activation. Histological examination of kidney sections reveal that canagliflozin attenuates ISO-mediated increases in inflammatory cell infiltration, collagen deposition and fibrosis. Finally, consistent with these findings, canagliflozin treatment improves kidney function in ISO-treated rats, suggesting that the antioxidant effects may be clinically translatable.

Expression of ADR-α1, 2 and ADR-β2 in cumulus cell culture of infertile women with polycystic ovary syndrome and poor responder who are a candidate for IVF: the novel strategic role of clonidine in this expression

Objective Alpha and beta-adrenoceptors (ADR-α1, 2, and β2) play a regulatory role in the folliculogenesis and steroidogenesis in the ovarian follicles. This study aimed to measure these adrenoceptors mRNA and its protein levels in cumulus cells (CCs) culture of poor ovarian reserve (POR) and polycystic ovarian syndrome (PCOS) infertile women (IVF candidate) and the effect of clonidine treatment at CCs culture. Methods This case/control study was conducted in 2017 includes a control (donation oocytes) and two studies (PCO and POR) groups. The ovulation induction drugs were prescribed in all groups. After the oocyte puncture, the follicular fluid was collected and CCs were isolated were cultured. RNA was extracted and cDNA was synthesized and designed the primer for the ADR-α1, 2 and ADR-β2 gene expression. The protein levels were investigated by Western Blot. Results The results showed a high level of three adrenergic expressions in PCO women compared to the control group (p-value <.001), which can be reduced by clonidine. POR group showed a significant decrease in the gene expression of ADR-α1 (p-value = .004) and ADR-α2 (p-value = .003) compared to the control group and clonidine treatment had no effect. Conclusion The significant increase of three adrenoceptors gene expression and protein levels in CCs culture indicate to the hyperactivity of the ovarian sympathetic nervous system at the receptor levels in women with PCOS, and clonidine confirmed it by reducing this expression. In POR women, the reduction of ADR-α1, 2 expressions maybe lead to the aging process in the ovary.

Abstract MP163: Renal Sympathetic Denervation (RDN) Improves Exercise Performance and Vascular Function in the Setting of Cardiometabolic HFpEF

Background: Heart failure with preserved ejection fraction (HFpEF) has emerged as a subclass of heart failure for which there are no effective treatments. HFpEF is induced in a large number of patients by central obesity, metabolic syndrome, and sustained activation of the sympathetic nervous system (SNS). Methods: We examined the effects of RDN in a clinically relevant model of HFpEF. The ZSF1-Obese rat exhibits the key components of cardiometabolic HFpEF including hypertension and diabetes. At 20 wks of age, ZSF1-Obese rats underwent bilateral radiofrequency RDN (RF-RDN) or sham RF-RDN and were followed for 6 weeks. LV function, blood pressure, LVEDP, vascular function, myocardial fibrosis, metabolic profiling, and exercise capacity were evaluated. We also assessed mitochondrial function of cardiac and skeletal muscle. Results: RF-RDN resulted in significant improvements in LV diastolic function, vascular relaxation, and exercise capacity. Significant reductions in blood pressure and LVEDP were observed following RF-RDN treatment. RF-RDN ameliorated cardiac fibrosis while improving cardiac and skeletal muscle mitochondrial function. We did not observe any effects of RF-RDN on the metabolic status of the ZSF-1 rat. Conclusion: Our data suggest that RF-RDN is a viable treatment option for cardiometabolic HFpEF through halting renal SNS hyperactivation and enhancing mitochondrial function to exert beneficial effects on the heart and circulation.

High Fat Diet‐Induced Plasticity in Parasympathetic Heart Rate Control: A Novel Mechanism for Cardiovascular Disease?

The pathological link between consumption of fat and the development of cardiovascular disease (CVD) has long been established. Still, the obesity‐independent mechanisms through which a high fat diet (HFD) contributes to the pathogenesis of CVDs like cardiac arrhythmias remain elusive. A wealth of preclinical, clinical, and epidemiological data has conclusively linked autonomic nervous system dysfunction—characterized by a potentiation of sympathetic activity, and a decrease in parasympathetic vagal tone—to a broad spectrum of cardiovascular diseases, including cardiac arrhythmias. Recent studies report that short‐term dietary consumption of a HFD induces sympathoexcitation and decreased cardiac parasympathetic tone in both animals and humans, suggesting autonomic dysfunctions occur well before the onset of overt obesity where aberrant metabolic dysregulations are evident. Presently, the majority of preclinical and clinical cardiovascular research targets sympathetic nervous system hyperactivity. Despite these advances, a significant clinical unmet need remains for alternative therapeutic strategies, especially for patients resistant to current pharmacotherapy interventions. In the present study, we investigated the mechanism by which HFD—independent of obesity—induces a decrease in cardiac parasympathetic tone, which is not presently understood. We hypothesized that HFD‐mediated increases in inhibitory current to cardiac vagal motoneurons lead to a decrease in cardiac vagal drive, thereby increasing CVD susceptibility.Our approach initially employed in vivo heart rate (HR) telemetry to monitor HFD‐induced alterations in HR. At the conclusion of the two weeks of HFD exposure, HFD‐fed mice exhibited a significant increase in food intake at day one of HFD exposure. This was not accompanied by significant changes in food intake, blood glucose levels, or body weight throughout the remaining duration of both diets. HR telemetry findings indicated that mice challenged with HFD for a two‐week period did not show significant changes in HR or HR variability parameters like RMSSD, HF power, or the LF/HF ratio compared to controls. Interestingly, pharmacological blockade of the parasympathetic and sympathetic nervous systems during HR telemetry recording suggested there is a preferential dysfunction in parasympathetic drive in animals fed HFD compared to control chow‐fed mice. When challenged with a bolus injection of glucose, HFD‐fed mice exhibited significantly higher blood glucose levels 30, 60, and 120 minutes after the injection. These changes were accompanied by a significantly higher HR at 15 minutes after injection. To determine if cardiac motoneuron output might play a role, we employed retrograde tracing to identify cardiac‐projecting nucleus ambiguus neurons and in vitro whole‐cell patch‐clamp electrophysiology to assess their signaling properties under control and HFD conditions. Our findings suggest that increasing parasympathetic drive prior and during HFD exposure may be a promising therapeutic target for preventing the aberrant effects of a HFD on HR.Support or Funding InformationAmerican Heart Association 16SDG26590000 to CRB and NIH Initiative for Maximizing Student Development grant R25GM095480‐08 to LE.

Radiofrequency Renal Denervation (RF‐RDN) Ameliorates the Severity of Heart Failure with Preserved Ejection Fraction (HFpEF)

BackgroundHeart failure with preserved ejection fraction (HFpEF) is a complex heterogeneous syndrome that results in significant morbidity, repeat hospitalizations, and excessive healthcare expenditures. At present, there are no FDA approved therapies for HFpEF patients. Subtypes of HFpEF have recently been characterized, defining these presentations using phenomapping methodologies. One subtype, termed obesity‐cardiometabolic HFpEF, demonstrates global sympathetic nervous system hyperactivity and metabolic disturbances. The role of the kidney in the pathophysiologic development of these disturbances is significant, suggesting that renal‐based therapies may prove beneficial in HFpEF. Renal denervation (RDN) has been shown to lower blood pressure in the setting of resistant hypertension.MethodsWe investigated obese ZSF‐1 rats (n = 8–10 rats/study group) that underwent either radio‐frequency renal denervation (RF‐RDN) or a sham RF‐RDN surgery. The rats were enrolled at 16 weeks of age and RF‐RDN or sham surgery was performed when the rats were 20 weeks of age followed by a 6 week observation period. We investigated a spectrum of clinically relevant parameters were assessed, including echocardiographic, radiotelemetry, exercise capacity, vascular function, cardiac fibrosis, and metabolic profiling (i.e. glucose tolerance, insulin sensitivity, serum lipids, and obesity).ResultsRats undergoing RF‐RDN treatment exhibited significant improvements in left ventricular (LV) diastolic function according to echocardiographic determination of E/E’ ratio (Figure 1A). RF‐RDN treatment resulted in a significant improvement in exercise capacity (Figure 1B). Radiotelemetry recordings shows a significant reduction in systolic blood pressure and a halt in the progression of hypertension (Figure 1C). Histological evaluation of the hearts revealed attenuation of cardiac fibrosis following RF‐RDN treatment. RF‐RDN therapy failed to exert beneficial effects in terms of obesity, diabetes, or dyslipidemia in the ZSF‐1 obese rat.ConclusionOur findings suggest that RF‐RDN may be a viable option for the treatment of HFpEF by lowering blood pressure, improving cardiac function, and increasing exercise capacity. These findings suggest that this treatment may improve the quality of life in the setting of clinical HFpEF.Support or Funding InformationNational Institutes of General Medical Sciences (NIGMS) COBRE grant no. P30GM106392 to Dr. KapustaA. Diastolic functional measure of E/E’ ratio six weeks after RF‐RDN or sham RF‐RDN surgery. B. Exercise capacity duration six weeks after RF‐RDN or sham RF‐RDN surgery. C. Weekly conscious systolic blood pressure recordings. (*p &lt; 0.05; **p &lt; 0.01)Figure 1

Uncontrolled Arterial Hypertension: Kidney, Neurohormonal Imbalance, and Approaches to Antihypertensive Drug Therapy

Resistant and refractory arterial hypertensions are two distinct clinical phenotypes of uncontrolled arterial hypertension (AH), which differ in their sensitivity to antihypertensive drug therapy. The review presents data obtained in clinical studies devoted to elucidating the involvement of disorders of neurohormonal status and renal function in the formation of resistant and refractory arterial hypertension, to and the development of new approaches to increasing the effectiveness of antihypertensive therapy in these patient's populations. The results of these studies have shown that in patients with uncontrolled arterial hypertension, despite prolonged intake ≥ 3 antihypertensive drugs with different mechanisms of action, including a diuretic, excess sodium reabsorption persists in the distal segments of nephron due to increased aldosterone activity and sympathetic nervous system hyperactivity. In this regard, special attention has been paid to the data of PATHWAY-2, PATHWAY-3 and ReHOT trials that in patients with resistant AH tested the clinical efficacy of spironolactone, amiloride, and antiadrenergic drugs bisoprolol, doxazosin and clonidine, suppressing activity of the sympathetic nervous system.

In rats with estradiol valerate-induced polycystic ovary syndrome, the acute blockade of ovarian \u03b2-adrenoreceptors improve ovulation

BackgroundPolycystic ovary syndrome is characterized by hyperactivity of the ovarian sympathetic nervous system, increases in the content and release of norepinephrine, as well as decreases in the number of β-adrenoreceptors. In the present study, β-adrenoreceptors in the ovaries of rats with polycystic ovary syndrome were blocked and analyzed the resultant effects on ovulation, hormone secretion and the enzymes responsible for the synthesis of catecholamines.MethodsAt 60 days of age, vehicle or estradiol valerate-treated rats were injected with propranolol [10− 4 M] into the ovarian bursas on oestrus day. The animals were sacrificed on the next day of oestrus, and the ovulation response, the steroid hormone levels in the serum and the immunoreactivity of tyrosine hydroxylase and dopamine β-hydroxylase in the ovaries were measured.ResultsIn animals with the induction of polycystic ovary syndrome and β-adrenoreceptor blocking, ovulation was restored in more than half of the animals and resulted in decreased hyperandrogenism with respect to the levels observed in the estradiol valerate-treated group. Tyrosine hydroxylase and dopamine β-hydroxylase were present in the theca cells of the growing follicles and the interstitial gland. Injection of propranolol restored the tyrosine hydroxylase and ovarian dopamine β-hydroxylase levels in rats with polycystic ovary syndrome induction.ConclusionsThe results suggest that a single injection into the ovarian bursas of propranolol, a nonselective antagonist of β-adrenoreceptor receptors, decreases the serum testosterone concentration and the formation of ovarian cysts, improving the ovulation rate that accompanies lower levels of tyrosine hydroxylase and dopamine β-hydroxylase in the ovary.

The Role of Cardioselective versus Non-Cardioselective Beta-Adrenergic Blockade in the Acute Phase of Takotsubo Cardiomyopathy

Background Takotsubo cardiomyopathy (TC) has been associated with hyperactivation of sympathetic nervous system leading to transient left ventricular (LV) dysfunction following acute emotional or physical stress. There are no controlled studies or guidelines on how to treat TC and its therapy remains empirical. We aim to study the effects of cardioselective versus non-cardioselective beta-adrenergic blockade on LV recovery in follow-up transthoracic echocardiographic studies in patients with newly diagnosed TC. Methods We performed retrospective chart review analysis of all patients who were admitted to Bronx-Care Health System from January 1, 2007 through December 31, 2017 with the diagnosis of TC. All cases of TC who presented with acute coronary syndrome and angiogram showing apical ballooning with preserved base of the heart were included. We excluded significant coronary artery disease, prior known cardiomyopathy, suspicion of any myocarditis and recent head trauma or intracranial hemorrhage. Primary outcome variables included improvement in LV end-diastolic and end-systolic volumes, LV ejection fraction as well as degree of LV wall motion abnormalities improvement from the baseline transthoracic echocardiography with use of either cardioselective or non-cardioselective beta-adrenergic antagonists. The secondary outcomes included morbidity and mortality including all-cause and HF readmission in 30 days as well as mortality at 6 and 12 months. Results Of the 2010 patients admitted with acute coronary syndrome and underwent coronary angiogram, 60 patients (2.98%) were found to have TC. The mean age for TC patients was 62 (±16) years with more females (75%) than males. Urine drug screen was positive in 38% of our population and 6% had HIV disease. The average BMI in our study subject was 23.54 KG/M2 which was observed 19.45 KG/M2 in subjects with positive drug screen (p value= 0.0213). Beta-blocker was used in 83% of the cases with 63% were on cardioselective beta-adrenergic blockade and 27% were on non-cardioselective beta-adrenergic blockade. The relationship observed between echocardiographic parameters and type of beta-adrenergic blockade did not differ. The 30-day readmission rate and all-cause mortality were found to be similar in both groups. Positive urine drug screen was not associated with 30-day readmission and all-cause mortality in TC. (p value= 0.262) Conclusions Use of Beta-adrenergic blockers did not show any improvement in echocardiographic parameters in TC. It was not associated with improved adverse outcomes such as 30-day readmission rate and all-cause mortality in TC. The study challenges the proposed role of beta-blockers in improving outcomes in patients with TC.