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1.
Cell Rep Med ; : 101754, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39383869

RESUMO

The gut permeability significantly increases after ischemic stroke, partly due to disrupted mucosal barrier, but the mechanism remains elusive. Here, we found that the mucus disruption starts at 2 h post stroke, whereas goblet cell functions remain intact. Meanwhile, the flagellated bacteria Helicobacter thrives and penetrates in the mucus layer. Elimination of the mucosal microbiota or transplantation of Helicobacter in germ-free mice reveals an important role of the mucosal microbiota in mucus disruption. The bacterial invasion is due to downregulated Toll-like receptor 5 (TLR5) and its downstream products flagellin-specific IgA and antimicrobial peptides. Knockdown of intestinal TLR5 increases the abundance of flagellated bacteria and exacerbates mucus injury. Intestinal TLR5 is downregulated by the activation of sympathetic nerve. Serum noradrenaline level is positively associated with flagellin level in patients with stroke and patients' prognosis. These findings reveal a neural pathway in which the sympathetic nerve disrupts the mucosal barrier, providing potential therapeutic targets for stroke injury.

2.
J Pharm Bioallied Sci ; 16(Suppl 3): S2978-S2980, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39346186

RESUMO

Localized unilateral hyperhidrosis (LUH) is a rare disorder with intense sweating in a specific area, often without common triggers. This study details a 32-year-old man with activity-induced unilateral sweating. Comprehensive tests ruled out serious conditions. This unique case adds to the limited reports of LUH in healthy individuals.

3.
J Physiol Sci ; 74(1): 48, 2024 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-39342112

RESUMO

Although sympathetic suppression is considered one of the mechanisms for cardioprotection afforded by sodium-glucose cotransporter 2 (SGLT2) inhibitors, whether SGLT2 inhibition acutely modifies sympathetic arterial pressure (AP) regulation remains unclear. We examined the acute effect of an SGLT2 inhibitor, empagliflozin (10 mg/kg), on open-loop baroreflex static characteristics in streptozotocin (STZ)-induced type 1 diabetic and control (CNT) rats (n = 9 each). Empagliflozin significantly increased urine flow [CNT: 25.5 (21.7-31.2) vs. 55.9 (51.0-64.5), STZ: 83.4 (53.7-91.7) vs. 121.2 (57.0-136.0) µL·min-1·kg-1, median (1st-3rd quartiles), P < 0.001 for empagliflozin and STZ]. Empagliflozin decreased the minimum sympathetic nerve activity (SNA) [CNT: 15.7 (6.8-18.4) vs. 10.5 (2.9-19.0), STZ: 36.9 (25.7-54.9) vs. 32.8 (15.1-37.5) %, P = 0.021 for empagliflozin and P = 0.003 for STZ], but did not significantly affect the peripheral arc characteristics assessed by the SNA-AP relationship. Despite the significant increase in urine flow and changes in several baroreflex parameters, empagliflozin preserved the overall sympathetic AP regulation in STZ-induced diabetic rats. The lack of a significant change in the peripheral arc may minimize reflex sympathetic activation, thereby enhancing a cardioprotective benefit of empagliflozin.


Assuntos
Barorreflexo , Compostos Benzidrílicos , Diabetes Mellitus Experimental , Glucosídeos , Inibidores do Transportador 2 de Sódio-Glicose , Sistema Nervoso Simpático , Animais , Compostos Benzidrílicos/farmacologia , Glucosídeos/farmacologia , Barorreflexo/efeitos dos fármacos , Masculino , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Experimental/tratamento farmacológico , Ratos , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiopatologia , Pressão Sanguínea/efeitos dos fármacos , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 1/tratamento farmacológico , Estreptozocina , Ratos Wistar , Micção/efeitos dos fármacos
4.
bioRxiv ; 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39314391

RESUMO

Tissue fibrosis contributes to pathology in vital organs including the lung. Curative therapies are scant. Myofibroblasts, pivotal effector cells in tissue fibrosis, accumulate via incompletely understood interactions with their microenvironment. In an investigative platform grounded in experimental lung biology, we find that sympathetic innervation stimulates fibrotic remodeling via noradrenergic α1-adrenergic receptor engagement in myofibroblasts. We demonstrate the anti-fibrotic potential of targeted sympathetic denervation and pharmacological disruption of noradrenergic neurotransmitter functions mediated by α1-adrenoreceptors (α1-ARs). Using the α1-adrenoreceptor subtype D as a representative α1-AR, we discover direct noradrenergic input from sympathetic nerves to lung myofibroblasts utilizing established mouse models, genetic denervation, pharmacologic interventions, a newly invented transgenic mouse line, advanced tissue mimetics, and samples from patients with diverse forms of pulmonary fibrosis. The discovery of this previously unappreciated nerve-fibroblast axis in the lung demonstrates the crucial contribution of nerves to tissue repair and heralds a novel paradigm in fibrosis research.

5.
PeerJ ; 12: e18166, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39346076

RESUMO

Background: Fibrosis after nephrotoxic injury is common. Activation of the paraventricular nucleus (PVN) renin-angiotensin system (RAS) and sympathetic nervous system (SNS) are common mechanism of renal fibrosis. However, there have limited knowledge about which brain regions are most affected by Angiotensin II (Ang II) after nephrotoxic injury, what role does Angiotensin II type 1a receptors (AT1R) signaling play and how this affects the outcomes of the kidneys. Methods: In nephrotoxic folic acid-induced chronic kidney disease (FA-CKD) mouse models, we have integrated retrograde tracer techniques with studies on AT1afl/fl mice to pinpoint an excessively active central pathway that connects the paraventricular nucleus (PVN) to the rostral ventrolateral medulla (RVLM). This pathway plays a pivotal role in determining the kidney's fibrotic response following injury induced by folic acid. Results: FA-CKD (vs sham) had increased in the kidney SNS activity and Ang II expression in the central PVN. The activation of Ang II in the PVN triggers the activation of the PVN-RVLM pathway, amplifies SNS output, thus facilitating fibrosis development in FA-CKD mouse. Blocking sympathetic traffic or deleting AT1a in the PVN alleviated renal fibrosis in FA-CKD mice. Conclusions: The FA-CKD mice have increased the expression of Ang II in PVN, thereby activating AT1a-positive PVN neurons project to the RVLM, where SNS activity is engaged to initiate fibrotic processes. The Ang II in PVN may contribute to the development of kidney fibrosis after nephrotoxic folic acid-induced kidney injury.


Assuntos
Modelos Animais de Doenças , Fibrose , Ácido Fólico , Rim , Receptor Tipo 1 de Angiotensina , Insuficiência Renal Crônica , Sistema Nervoso Simpático , Animais , Receptor Tipo 1 de Angiotensina/metabolismo , Receptor Tipo 1 de Angiotensina/genética , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/induzido quimicamente , Insuficiência Renal Crônica/metabolismo , Camundongos , Ácido Fólico/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/patologia , Rim/patologia , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/inervação , Angiotensina II/farmacologia , Masculino , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/patologia , Camundongos Endogâmicos C57BL
6.
Auton Neurosci ; 256: 103217, 2024 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-39270515

RESUMO

Significant volume is pooled in veins in humans and the amount is dramatically altered by various physiological stresses and diseases. Several animal and human studies demonstrated that limb venous distension evoked significant increases in blood pressure and sympathetic nerve activity (venous distension reflex, VDR). VDR has attracted much attention because of its potential to explain the still unknown mechanism of autonomic dysfunction in several diseases, which would lead to a new treatment approach. This mini review discusses accumulated evidence of VDR at this point and what should be investigated in the future to apply the current understanding of VDR in clinical practice.

7.
J Intensive Care ; 12(1): 31, 2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39223624

RESUMO

BACKGROUND: Sympathetic nerve activity (SNA) plays a central role in the pathogenesis of several diseases such as sepsis and chronic kidney disease (CKD). Activation of microglia in the paraventricular nucleus of the hypothalamus (PVN) has been implicated in SNA. The mechanisms responsible for the adverse prognosis observed in sepsis associated with CKD remain to be determined. Therefore, we aimed to clarify the impact of increased SNA resulting from microglial activation on hemodynamics and organ damage in sepsis associated with CKD. METHODS AND RESULTS: In protocol 1, male Sprague-Dawley rats underwent either nephrectomy (Nx) or sham surgery followed by cecal ligation and puncture (CLP) or sham surgery. After CLP, Nx-CLP rats exhibited decreased blood pressure, increased heart rate, elevated serum creatinine and bilirubin levels, and decreased platelet count compared to Nx-Sham rats. Heart rate variability analysis revealed an increased low to high frequency (LF/HF) ratio in Nx-CLP rats, indicating increased SNA. Nx-CLP rats also had higher creatinine and bilirubin levels and lower platelet counts than sham-CLP rats after CLP. In protocol 2, Nx-CLP rats were divided into two subgroups: one received minocycline, an inhibitor of microglial activation, while the other received artificial cerebrospinal fluid (CSF) intracerebroventricularly via an osmotic minipump. The minocycline-treated group (Nx-mino-CLP) showed attenuated hypotensive and increased heart rate responses compared to the CSF-treated group (Nx-CSF-CLP), and the LF/HF ratio was also decreased. Echocardiography showed larger left ventricular dimensions and inferior vena cava in the Nx-mino-CLP group. In addition, creatinine and bilirubin levels were lower and platelet counts were higher in the Nx-mino-CLP group compared to the Nx-CSF-CLP group. CONCLUSIONS: In septic rats with concomitant CKD, SNA was significantly enhanced and organ dysfunction was increased. It has been suggested that the mechanism of exacerbated organ dysfunction in these models may involve abnormal systemic hemodynamics, possibly triggered by activation of the central sympathetic nervous system through activation of microglia in the PVN.

9.
J Physiol ; 2024 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-39276118

RESUMO

We tested the hypothesis that in human hypertension, an increased tonicity/sensitivity of the peripheral chemoreflex causes a sympathetically mediated restraint of nutritive blood flow to the exercising muscles. Fourteen patients with treated hypertension (age 69 ± 11 years, 136 ± 12/80 ± 11 mmHg; mean ± SD) were studied under conditions of intravenous 0.9% saline (control) and low-dose dopamine (2 µg kg-1 min-1) to inhibit the peripheral chemoreflex, at baseline, during isocapnic hypoxic rebreathing and during rhythmic handgrip exercise (3 min, 50% maximum voluntary contraction). At baseline, dopamine did not change mean blood pressure (95 ± 10 vs. 98 ± 10 mmHg, P = 0.155) but increased brachial artery blood flow (59 ± 20 vs. 48 ± 16 ml min-1, P = 0.030) and vascular conductance (0.565 ± 0.246 vs. 0.483 ± 0.160 ml min-1 mmHg-1; P = 0.039). Dopamine attenuated the increase in mean blood pressure (∆3 ± 4 vs. ∆8 ± 6 mmHg, P = 0.007) to isocapnic hypoxic rebreathing and reduced peripheral chemoreflex sensitivity by 28 ± 37% (P = 0.044). Rhythmic handgrip exercise induced increases in brachial artery blood flow and vascular conductance (both P < 0.05 vs. rest after 45 s) that were greater with dopamine than saline (e.g. Δ76 ± 54 vs. Δ60 ± 43 ml min-1 and Δ0.730 ± 0.440 vs. Δ0.570 ± 0.424 ml min-1 mmHg-1, respectively, at 60 s; main effect of condition both P < 0.0001). Our results indicate that the peripheral chemoreflex is tonically active at rest and restrains the blood flow and vascular conductance increases to exercise in treated human hypertension. KEY POINTS: It was hypothesised that in human hypertension, an increased tonicity/sensitivity of the peripheral chemoreflex causes a sympathetically mediated restraint of nutritive blood flow to the exercising muscles. Treated patients with hypertension (n = 14) were studied under conditions of intravenous 0.9% saline (control) and low-dose dopamine (2 µg kg-1 min-1) to inhibit the peripheral chemoreflex. Low-dose dopamine reduced resting ventilation and peripheral chemoreflex sensitivity, and while mean blood pressure was unchanged, brachial artery blood flow and vascular conductance were increased. Low-dose dopamine augmented the brachial artery blood flow and vascular conductance responses to rhythmic handgrip. These findings indicate that the peripheral chemoreflex is tonically active at rest and restrains the blood flow, and vascular conductance increases to exercise in treated human hypertension.

10.
Hypertens Res ; 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39261702

RESUMO

Bilateral renal denervation (RDN) decreases arterial pressure (AP) or delays the development of hypertension in spontaneously hypertensive rats (SHR), but whether bilateral RDN significantly modifies urine output function during baroreflex-mediated acute AP changes remains unknown. We quantified the relationship between AP and normalized urine flow (nUF) in SHR that underwent bilateral RDN (n = 9) and compared the results with those in sham-operated SHR (n = 9). Moreover, we examined the acute effect of an angiotensin II type 1 receptor blocker telmisartan (2.5 mg/kg) on the AP-nUF relationship. Bilateral RDN significantly decreased AP by narrowing the response range of the total arc of the carotid sinus baroreflex. The slopes of nUF versus the mean AP (in µL·min-1·kg-1·mmHg-1) in the sham and RDN groups under baseline conditions were 0.076 ± 0.045 and 0.188 ± 0.039, respectively; and those after telmisartan administration were 0.285 ± 0.034 and 0.416 ± 0.078, respectively. The effect of RDN on the nUF slope was marginally significant (P = 0.059), which may have improved the controllability of urine output in the RDN group. The effect of telmisartan on the nUF slope was significant (P < 0.001) in the sham and RDN groups, signifying the contribution of circulating or locally produced angiotensin II to determining urine output function regardless of ongoing renal sympathetic nerve activity.

11.
Artigo em Inglês | MEDLINE | ID: mdl-39298550

RESUMO

Renal denervation (RDN) has been used for treating resistant hypertension. A few recent studies show vagal innervation of kidneys causing confusion. This study aimed to provide anatomical and functional evidence for renal autonomic innervation. Experiments were performed in male Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Pseudorabies virus (PRV) in paraventricular nucleus and rostral ventrolateral medulla was prevented by bilateral RDN, but not subdiaphragmatic vagotomy. PRV did not appear in dorsal motor nucleus of vagus and nucleus tractus solitarii 72 h after renal injection of PRV. Adrenergic fibers were approximately 7 times more than cholinergic fibers in main renal artery (MRA) and its first (1RA) and second grade (2RA) branches. Adrenergic fibers in 1RA were more than these in MRA and 2RA. Tyrosine hydroxylase immunoreactivity in these arteries was higher in SHR than WKY. Norepinephrine (NE) increased, and α-receptor antagonist reduced vascular ring tension of renal arteries. The effect of NE was greater in 1RA and 2RA than MRA, which was prevented by α-receptor antagonist. Acetylcholine (ACh) or blockage of ß-receptors, M- or N-receptors had no significant effects on vascular ring tension and the effect of NE. Renal blood flow was reduced by electrical stimulation of renal nerves, but not affected by stimulation of subdiaphragmatic vagus. These results provide anatomical and functional evidence that kidneys are innervated and renal blood flow is regulated by renal sympathetic nerves rather than vagus. Renal vasoconstriction is regulated by NE and adrenergic fibers rather than ACh or cholinergic fibers in WKY and SHR.

12.
Clin Exp Hypertens ; 46(1): 2402260, 2024 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-39305040

RESUMO

BACKGROUND: Gestational diabetes can lead to increased blood pressure in offspring, accompanied by impaired renal sodium excretion function and vasoconstriction and diastole dysfunction. However, there are few studies on whether it is accompanied by increased sympathetic nerve activity. METHODS: Pregnant C57BL/6 mice were intraperitoneally injected with streptozotocin (35 mg/kg) or citrate buffer at day 0 of gestation. The mice of control mother offspring (CMO) and diabetic mother offspring (DMO) at 16 weeks of age were infused with vehicle (artificial cerebrospinal fluid, aCSF, 0.4 µL/h) or tempol (1 mmol/L, 0.4 µL/h) into the bilateral paraventricular nucleus (PVN) of mice for 4 weeks, respectively. RESULTS: Compared with CMO group, SBP and peripheral sympathetic nerve activity (increased heart rate, LF/HF and plasma norepinephrine and decreased SDNN and RMSSD) were increased in DMO group, which was accompanied by increased angiotensin II type-1 receptor (AT1R) expression and function in PVN. The increase in AT1R expression levels was attributed to a decrease in the methylation level of the AT1R promoter region, resulting in an increase in AT1R mRNA levels in PVN of DMO. Moreover, compared with CMO group, the levels of oxidative stress were increased and DNMT1 expression was decreased in PVN of DMO. Bilateral PVN infusion of tempol attenuated oxidative stress increased the level of DNMT1 expression and the binding of DNMT1 to the AT1R promoter region, which reduced mRNA and protein expression level of AT1R, heart rate and SBP in DMO, but not in CMO. CONCLUSIONS: The present study provides evidence for overactive sympathetic nervous systems in the pathogenesis of gestational diabetes-induced hypertension in offspring. Central antioxidant intervention in the PVN may be an important treatment strategy for fetal-programmed hypertension.


Assuntos
Diabetes Mellitus Experimental , Diabetes Gestacional , Hipertensão , Camundongos Endogâmicos C57BL , Sistema Nervoso Simpático , Animais , Gravidez , Sistema Nervoso Simpático/fisiopatologia , Feminino , Camundongos , Diabetes Gestacional/fisiopatologia , Hipertensão/fisiopatologia , Hipertensão/etiologia , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Experimental/complicações , Óxidos N-Cíclicos/farmacologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Marcadores de Spin , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/fisiopatologia , Pressão Sanguínea/fisiologia , Receptor Tipo 1 de Angiotensina/genética , Masculino , Frequência Cardíaca/fisiologia , Estresse Oxidativo
13.
Toxicon ; 250: 108100, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39299653

RESUMO

Complex Regional Pain Syndrome (CRPS) is characterized by pain, swelling, limited range of motion, skin changes, vasomotor instability, and bone demineralization. This study aims to assess the efficacy of botulinum toxin type A (BoNT-A) in the treatment of CRPS. We conducted a systematic literature review following the PRISMA guidelines, using the PICO strategy (Patient, Intervention, Comparison and Outcome) with the following criteria: P = Patients with CRPS; I = Botulinum toxin; C = Placebo or active drug; and O = Pain relief. Three randomized controlled trials with placebo controls were included, involving a total of 64 patients, 36 of whom received BoNT-A in doses ranging from 40U to 200U. The studies examined both lumbar sympathetic block and local application methods. Botulinum toxin shows promise in alleviating pain associated with CRPS, particularly when used as an adjunct to lumbar sympathetic blockade. However, the limited number of studies and small sample sizes impede reaching definitive conclusions regarding its efficacy and safety. Notably, local applications (intradermal or subcutaneous) require further investigation, as current evidence is insufficient and reports indicate patient discomfort. While preliminary findings suggest potential benefits of BoNT-A in managing CRPS, larger randomized trials are necessary to confirm its efficacy and safety.

14.
Front Immunol ; 15: 1455407, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39257579

RESUMO

Macrophages play a multifaceted role in maintaining tissue homeostasis, fighting infections, and regulating cold-induced thermogenesis. The brown adipose tissue (BAT) is crucial for maintaining body temperature during cold exposure. Cold stress triggers the sympathetic nervous system to release norepinephrine (NE), which activates BAT via ß3-adrenergic receptors, initiating lipolysis and glycolysis. BAT-infiltrating macrophages can either hinder or enhance thermogenesis by controlling the interplay between BAT cells and sympathetic nerves. In this study we report on a unique population of CD3+F4/80+ dual lineage co-expressing (DE) cells within the interscapular BAT (iBAT), that increased following chronic adrenergic stimulation. In forward scatter/side scatter plots, they formed a cluster distinct from lymphocytes, appearing larger and more complex. These CD3+F4/80+ DE cells demonstrated the lack of T cell markers CD62L and TCRß and expressed higher levels of Ly6C, F4/80, and CD11b markers compared to T cells and CD3- macrophages. Furthermore, analysis revealed two subpopulations within the CD3+F4/80+ DE population based on MHCII expression, with the proportion of MHCII-low subset increasing with adrenergic stimulation. This novel DE population within iBAT, unequivocally identified by the its unique surface marker profile, warrants further investigation into the intricate mechanisms governing adaptive thermogenesis regulation.


Assuntos
Tecido Adiposo Marrom , Complexo CD3 , Macrófagos , Termogênese , Animais , Tecido Adiposo Marrom/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Complexo CD3/metabolismo , Norepinefrina/farmacologia , Norepinefrina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Receptores Adrenérgicos beta 3/metabolismo
15.
Hypertens Res ; 47(10): 2685-2692, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39095482

RESUMO

This review explores the various pathophysiological factors influencing antihypertensive effects, involving the regulation of vascular resistance, plasma volume, cardiac function, and the autonomic nervous system, emphasizing the interconnected processes regulating blood pressure (BP). The kidney's pivotal role in BP control and its potential contribution to hypertension is complicated but important to understand the effective mechanisms of renal denervation (RDN), which may be a promising treatment for resistant hypertension. Excessive stimulation of the sympathetic nervous system or the renin-angiotensin-aldosterone system (RAAS) can elevate BP through various physiological changes, contributing to chronic hypertension. Renal sympathetic efferent nerve activation leads to elevated norepinephrine levels and subsequent cascading effects on vasoconstriction, renin release, and sodium reabsorption. RDN reduces BP in resistant hypertension by potentially disrupting sensory afferent nerves, decreasing feedback activation to the central nervous system, and reducing efferent sympathetic nerve activity in the heart and other structures. RDN may also modulate central sympathetic outflow and inhibit renal renin-angiotensin system overactivation. While evidence for RDN efficacy in hypertension is increasing, accurate patient selection becomes crucial, considering complex interactions that vary among patients. This review also discusses methods to evaluate autonomic nerve activity from the golden standard to new potential examination for finding out optimization in stimulation parameters or rigorous patient selection based on appropriate biomarkers.


Assuntos
Sistema Nervoso Autônomo , Hipertensão , Rim , Simpatectomia , Sistema Nervoso Simpático , Humanos , Rim/inervação , Rim/fisiopatologia , Hipertensão/fisiopatologia , Hipertensão/cirurgia , Sistema Nervoso Simpático/fisiopatologia , Sistema Nervoso Autônomo/fisiopatologia , Sistema Renina-Angiotensina/fisiologia , Pressão Sanguínea/fisiologia
17.
J Neurophysiol ; 132(3): 922-928, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39110514

RESUMO

Preclinical models indicate that amiloride (AMD) reduces baroreflex sensitivity and perturbs homeostatic blood pressure (BP) regulation. However, it remains unclear whether these findings translate to humans. This study investigated whether oral administration of AMD reduces spontaneous cardiac and sympathetic baroreflex sensitivity and perturbs BP regulation in healthy young humans. Heart rate (HR; electrocardiography), beat-to-beat BP (photoplethysmography), and muscle sympathetic activity (MSNA, microneurography) were continuously measured in 10 young subjects (4 females) during rest across two randomized experimental visits: 1) after 3 h of oral administration of placebo (PLA, 10 mg of methylcellulose within a gelatin capsule) and 2) after 3 h of oral administration of AMD (10 mg). Visits were separated for at least 48 h. We calculated the standard deviation and other indices of BP variability. Spontaneous cardiac baroreflex was assessed via the sequence technique and cardiac autonomic modulation through time- and frequency-domain HR variability. The sensitivity (gain) of the sympathetic baroreflex was determined via weighted linear regression analysis between MSNA and diastolic BP. AMD did not affect HR, BP, and MSNA compared with PLA. Indexes of cardiac autonomic modulation (time- and frequency-domain HR variability) and BP variability were also unchanged after AMD ingestion. Likewise, AMD did not modify the gain of both spontaneous cardiac and sympathetic arterial baroreflex. A single oral dose of AMD does not affect spontaneous arterial baroreflex sensitivity and BP variability in healthy young adults.NEW & NOTEWORTHY Preclinical models indicate that amiloride (AMD), a nonselective antagonist of the acid-sensing ion channels (ASICs), impairs baroreflex sensitivity and perturbs blood pressure regulation. We translated these findings into humans, investigating the impact of acute oral ingestion of AMD on blood pressure variability and spontaneous cardiac and sympathetic baroreflex sensitivity in healthy young humans. In contrast to preclinical evidence, AMD does not impair spontaneous arterial baroreflex sensitivity and blood pressure variability in healthy young adults.


Assuntos
Amilorida , Barorreflexo , Pressão Sanguínea , Frequência Cardíaca , Humanos , Barorreflexo/efeitos dos fármacos , Barorreflexo/fisiologia , Amilorida/farmacologia , Amilorida/administração & dosagem , Masculino , Feminino , Adulto , Frequência Cardíaca/efeitos dos fármacos , Adulto Jovem , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Administração Oral , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Bloqueadores do Canal de Sódio Epitelial/farmacologia , Bloqueadores do Canal de Sódio Epitelial/administração & dosagem
18.
Immunity ; 57(9): 2030-2042.e8, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39116878

RESUMO

Hypertension is usually accompanied by elevated sympathetic tonicity, but how sympathetic hyperactivity is triggered is not clear. Recent advances revealed that microglia-centered neuroinflammation contributes to sympathetic excitation in hypertension. In this study, we performed a temporospatial analysis of microglia at both morphological and transcriptomic levels and found that microglia in the hypothalamic paraventricular nucleus (PVN), a sympathetic center, were early responders to hypertensive challenges. Vasculature analyses revealed that the PVN was characterized by high capillary density, thin vessel diameter, and complex vascular topology relative to other brain regions. As such, the PVN was susceptible to the penetration of ATP released from the vasculature in response to hemodynamic disturbance after blood pressure increase. Mechanistically, ATP ligation to microglial P2Y12 receptor was responsible for microglial inflammatory activation and the eventual sympathetic overflow. Together, these findings identified a distinct vasculature pattern rendering vulnerability of PVN pre-sympathetic neurons to hypertension-associated microglia-mediated inflammatory insults.


Assuntos
Hemodinâmica , Hipertensão , Microglia , Núcleo Hipotalâmico Paraventricular , Sistema Nervoso Simpático , Núcleo Hipotalâmico Paraventricular/metabolismo , Animais , Microglia/metabolismo , Hipertensão/fisiopatologia , Camundongos , Sistema Nervoso Simpático/fisiopatologia , Masculino , Camundongos Endogâmicos C57BL , Trifosfato de Adenosina/metabolismo , Receptores Purinérgicos P2Y12/metabolismo , Inflamação/imunologia , Pressão Sanguínea , Neurônios/metabolismo
19.
Front Pharmacol ; 15: 1424544, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39139635

RESUMO

Background: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) and dipeptidyl peptidase-4 inhibitors (DPP4i) are important second-line treatments for patients with type 2 diabetes mellitus (T2DM). Patients taking SGLT2i have favorable cardiovascular outcomes via various mechanisms, including autonomic nervous system (ANS) modulation. This study aimed to use neuro-electrocardiography (neuECG) to test the effects of SGLT2i or DPP4i on the ANS. Methods: Patients with T2DM, who did not reach target hemoglobin (Hb)A1C levels despite metformin treatment, were enrolled. SGLT2i or DPP4i were prescribed randomly unless a compelling indication was present. NeuECG and heart rate were recorded for 10 min before and after a 3-month treatment. The patients were treated according to standard practice and the obtained data for skin sympathetic nerve activity (SKNA) and ANS entropy were analyzed offline. Results: We enrolled 96 patients, of which 49 received SGLT2i and 47 received DPP4i. The baseline parameters were similar between the groups. No adverse event was seen during the study period. In the burst analysis of SKNA at baseline, all parameters were similar. After the 3-month treatment, the firing frequency was higher in SGLT2i group (0.104 ± 0.045 vs 0.083 ± 0.033 burst/min, p < 0.05), with increased long firing duration (7.34 ± 3.66 vs 5.906 ± 2.921, p < 0.05) in 3-s aSKNA scale; the other parameters did not show any significant change. By symbolic entropy, the most complex patterns (Rank 3) were found to be significantly higher in SGLT2i-treated patients than in DDP4i-treated group (0.084 ± 0.028 vs 0.07 ± 0.024, p = 0.01) and the direction of change in Rank 3, after SGLT2i treatment, was opposite to that observed in the DDP4i group (0.012 ± 0.036 vs. -0.005 ± 0.037, p = 0.024). Our findings demonstrated the favorable autonomic modulation by SGLTi and the detrimental effects of DPP4i on ANS. Conclusion: We demonstrated the autonomic modulation by SGLTi and DPP4i using SKNA in patients with DM, which might provide insights into the favorable outcomes of SGLT2i. Furthermore, we refined the analytical methods of neuECG, which uses SKNA to evaluate autonomic function.

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