Stellate Ganglia and Cardiac Sympathetic Overactivation in Heart Failure

Central SGLT2 mediate sympathoexcitation in hypertensive heart failure via attenuating subfornical organ endothelial cGAS ubiquitination to amplify neuroinflammation: Molecular mechanism behind sympatholytic effect of Empagliflozin

BACKGROUND

Sodium/glucose co-transporter 2 (SGLT2) inhibitors have transformed heart failure (HF) treatment, offering sympatholytic effects whose mechanisms are not fully understood. Our previous studies identified Cyclic GMP-AMP synthase (cGAS)-derived neuroinflammation in the Subfornical organ (SFO) as a promoter of sympathoexcitation, worsening myocardial remodeling in HF. This research explored the role of central SGLT2 in inducing endothelial cGAS-driven neuroinflammation in the SFO during HF and assessed the impact of SGLT2 inhibitors on this process.

METHODS

Hypertensive HF was induced in mice via Angiotensin II infusion for four weeks. SGLT2 expression and localization in the SFO were determined through immunoblotting and double-immunofluorescence staining. AAV9-TIE-shRNA (SGLT2) facilitated targeted SGLT2 knockdown in SFO endothelial cells (ECs), with subsequent analyses via immunoblotting, staining, and co-immunoprecipitation to investigate interactions with cGAS, mitochondrial alterations, and pro-inflammatory pathway activation. Renal sympathetic nerve activity and heart rate variability were measured to assess sympathetic output, alongside evaluations of cardiac function in HF mice.

RESULTS

In HF model mice, SGLT2 levels are markedly raised in SFO ECs, disrupting mitochondrial function and elevating oxidative stress. SGLT2 knockdown preserved mitochondrial integrity and function, reduced inflammation, and highlighted the influence of SGLT2 on mitochondrial health. SGLT2's interaction with cGAS prevented its ubiquitination and degradation, amplifying neuroinflammation and HF progression. Conversely, Empagliflozin counteracted these effects, suggesting that targeting the SGLT2-cGAS interaction as a novel HF treatment avenue.

CONCLUSION

This study revealed that SGLT2 directly reduced cGAS degradation in brain ECs, enhancing neuroinflammation in the SFO, and promoting sympathoexcitation and myocardial remodeling. The significance of the central SGLT2-cGAS interaction in cardiovascular disease mechanisms is emphasized.

Case Report: The unrelenting journey-successful resolution of catecholaminergic polymorphic ventricular tachycardia (CPVT) through right cardiac sympathetic denervation in a teenager after left cardiac sympathetic denervation

Background

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited arrhythmia disorder characterized by ventricular arrhythmia triggered by adrenergic stimulation.

Case presentation

A 9-year-old boy presented with convulsions following physical exertion. Bidirectional ventricular tachycardia (VT) during a treadmill test led to the diagnosis of catecholaminergic polymorphic ventricular tachycardia (CPVT). Genetic testing revealed a pathogenic variant of RYR2:c.720G>A (p.ArG2401His). Nadolol was initially started. However, he experienced aborted VT arrest three years later. Flecainide was thus added as dual therapy and he underwent left cardiac sympathetic denervation (LCSD). Subsequently, a transvenous implantable cardioverter-defibrillator (ICD) was implanted because he still had several episodes of bidirectional VT. Despite a good compliance to medication, the patient still had exercise induced VT episodes with new onset of atrial fibrillation. High dose nadolol was required and amiodarone was added. Despite maximizing the dosage of these three antiarrhythmics, the patient continued to experience multiple episodes of ventricular fibrillation with appropriate ICD shocks and persistent atrial arrhythmias. Right cardiac sympathetic denervation (RCSD) was performed as the last modality of treatment. Patient had a total elimination of VT post bilateral sympathectomy. He remained asymptomatic on follow up. A follow-up treadmill test showed no recurrence of exercise-induced PVCs and VT.

Conclusion

We illustrated the challenges and the complex decision-making process encountered in managing refractory CPVT. In patients unresponsive to conventional therapies, RCSD in additional to LCSD is a safe and effective alternative treatment. A history of LCSD should not preclude physicians from considering RCSD in children with refractory CPVT.

Revealing the molecular links between coronary heart disease and cognitive impairment: the role of aging-related genes and therapeutic potential of stellate ganglion block

Coronary heart disease (CHD) and cognitive impairment frequently co-occur in aging populations, yet the molecular mechanisms linking these conditions remain unclear. This study aims to elucidate the roles of key aging-related genes (ARGs), specifically FKBP5 and DDIT3, in the pathophysiology of CHD and cognitive impairment, and to evaluate the therapeutic potential of stellate ganglion block (SGB). Using single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (bulk RNA-seq) data, we identified FKBP5 and DDIT3 as pivotal genes upregulated in both conditions. Experimental findings show that SGB effectively modulates these ARG-related pathways through autonomic regulation, specifically suppressing estrogen and NF-κB signaling pathways, thereby reducing the expression of pro-inflammatory cytokines such as SRC, MMP2, FKBP5, IRAK1, and MYD88, while upregulating the vasodilation-related gene NOS3. This modulation improved endothelial and cardiac function and enhanced cerebral blood flow (CBF), leading to cognitive improvement. Behavioral assessments, including novel object recognition (NOR) and Morris water maze (MWM) tests, demonstrated that SGB-treated rats outperformed untreated MI rats, with significant cognitive recovery over time. Further support from laser Doppler flowmetry (LDF) and electroencephalogram (EEG) analyses revealed increased left frontal blood flow and stabilized neural activity, indicating a favorable neurophysiological environment for cognitive rehabilitation. Our findings suggest that left stellate ganglion block (LSGB) provides both cardiac and cognitive benefits through targeted gene modulation, establishing its therapeutic potential for addressing the intersecting pathologies of CHD and cognitive impairment.

Anatomical study with clinical significance of communicating and visceral branching of the cervical and upper thoracic sympathetic trunk

Current advances in the management of the autonomic nervous system in various cardiovascular diseases, and in treatments for pain or sympathetic disturbances in the head, neck, or upper limbs, necessitate a thorough understanding of the anatomy of the cervicothoracic sympathetic trunk. Our objective was to enhance our understanding of the origin and distribution of communicating branches and visceral cervicothoracic sympathetic nerves in human fetuses. This was achieved through a comprehensive topographic systematization of the branching patterns observed in the cervical and upper thoracic ganglia, along with the distribution of communicating branches to each cervical spinal nerve. We conducted detailed sub-macroscopic dissections of the cervical and thoracic regions in 20 human fetuses (40 sides). The superior and cervicothoracic ganglia were identified as the cervical sympathetic ganglia that provided the most communicating branches on both sides. The middle and accessory cervical ganglia contributed the fewest branches, with no significant differences between the right and left sides. The cervicothoracic ganglion supplied sympathetic branches to the greatest number of spinal nerves, spanning from C5 to T2. The distribution of communicating branches to spinal nerves was non-uniform. Notably, C3, C4, and C5 received the fewest branches, and more than half of the specimens showed no sympathetic connections. C1 and C2 received sympathetic connections exclusively from the superior ganglion. Spinal nerves that received more branches often did so from multiple ganglia. The vertebral nerve provided deep communicating branches primarily to C6, with lesser contributions to C7, C5, and C8. The vagus nerve stood out as the cranial nerve with the most direct sympathetic connections. The autonomic branching pattern and connections of the cervicothoracic sympathetic trunk are significantly variable in the fetus. A comprehensive understanding of the anatomy of the cervical and upper thoracic sympathetic trunk and its branches is valuable during autonomic interventions and neuromodulation. This knowledge is particularly relevant for addressing various autonomic cardiac diseases and for treating pain and vascular dysfunction in the head, neck, and upper limbs.

Chemoreflex sensitization occurs in both male and female rats during recovery from acute lung injury

Introduction

Sex-specific patterns in respiratory conditions, such as asthma, COPD, cystic fibrosis, obstructive sleep apnea, and idiopathic pulmonary fibrosis, have been previously documented. Animal models of acute lung injury (ALI) have offered insights into sex differences, with male mice exhibiting distinct lung edema and vascular leakage compared to female mice. Our lab has provided evidence that the chemoreflex is sensitized in male rats during the recovery from bleomycin-induced ALI, but whether sex-based chemoreflex changes occur post-ALI is not known. To bridge this gap, the current study employed the bleomycin-induced ALI animal model to investigate sex-based differences in chemoreflex activation during the recovery from ALI.

Methods

ALI was induced using a single intra-tracheal instillation of bleomycin (bleo, 2.5 mg/Kg) (day 1). Resting respiratory frequency (fR) was measured at 1-2 days pre-bleo, day 7 (D7) post-bleo, and 1 month (1 mth) post-bleo. The chemoreflex responses to hypoxia (10% O2, 0% CO2) and normoxic-hypercapnia (21% O2, 5% CO2) were measured before bleo administration (pre-bleo) and 1 mth post-bleo using whole-body plethysmography. The apnea-hypopnea Index (AHI), post-sigh apneas, and sighs were measured at each time point.

Results

There were no significant differences in resting fR between male and female rats at the pre-bleo time point or in the increase in resting fR at D7 post-bleo. At 1 mth post-bleo, the resting fR was partially restored in both sexes but the recovery towards normal ranges of resting fR was significantly lower in male rats. The AHI, post-sigh apneas, and sighs were not different between male and female rats pre-bleo and 1 mth post-bleo. However, at D7 post-bleo, the male rats exhibited a higher AHI than female rats. Both male and female rats exhibited a sensitized chemoreflex in response to hypoxia and normoxic-hypercapnia with no significant differences between sexes.

Conclusion

A sex difference in resting ventilatory parameters occurs post ALI with a prolonged increase in resting fR and larger AHI in male rats. On the other hand, we did not find any sex differences in the chemoreflex sensitization that occurs at 1 mth post-bleo. This work contributes to a better understanding of sex-based variations in lung disorders.

Electroacupuncture pretreatment mediates sympathetic nerves to alleviate myocardial ischemia-reperfusion injury via CRH neurons in the paraventricular nucleus of the hypothalamus

BACKGROUND

Myocardial ischemia-reperfusion can further exacerbate myocardial injury and increase the risk of death. Our previous research found that the paraventricular nucleus (PVN) of the hypothalamus plays a crucial role in the improvement of myocardial ischemia-reperfusion injury (MIRI) by electroacupuncture (EA) pretreatment, but its mechanism of action is still unclear. CRH neurons exhibit periodic concentrated expression in PVN, but further research is needed to determine whether they are involved in the improvement of MIRI by EA pretreatment. Meanwhile, numerous studies have shown that changes in sympathetic nervous system innervation and activity are associated with many heart diseases. This study aims to investigate whether EA pretreatment improves MIRI through sympathetic nervous system mediated by PVNCRH neurons.

METHODS

Integrated use of fiber-optic recording, chemical genetics and other methods to detect relevant indicators: ECG signals were acquired through Powerlab standard II leads, and LabChart 8 calculated heart rate, ST-segment offset, and heart rate variability (HRV); Left ventricular ejection fraction (LVEF), left ventricular short-axis shortening (LVFS), left ventricular end-systolic internal diameter (LVIDs) and interventricular septal thickness (IVSs) were measured by echocardiography; Myocardial infarct area (IA) and area at risk (AAR) were calculated by Evans-TTC staining. Pathological changes in cardiomyocytes were observed by HE staining; Changes in PVNCRH neuronal activity were recorded by fiber-optic photometry; Sympathetic nerve discharges were recorded for in vivo electrophysiology; NE and TH protein expression was assayed by Western blot.

RESULTS

Our data indicated that EA pretreatment can effectively alleviate MIRI. Meanwhile, we found that in the MIRI model, the number and activity of CRH neurons co labeled with c-Fos in the PVN area of the rat brain increased, and the frequency of sympathetic nerve discharge increased. EA pretreatment could reverse this change. In addition, the results of chemical genetics indicated that inhibiting PVNCRH neurons has a similar protective effect on MIRI as EA pretreatment, and the activation of PVNCRH neurons can counteract this protective effect.

CONCLUSION

EA pretreatment can inhibit PVNCRH neurons and improve MIRI by inhibiting sympathetic nerve, which offers fresh perspectives on the application of acupuncture in the management of cardiovascular disease.

Intraoperative sudden arrhythmias in cervical spine surgery adjacent to the stellate ganglion: A case report

BACKGROUND

Atrial arrhythmias such as paroxysmal supraventricular tachycardia (PSVT) and atrial flutter (AF) are common in the perioperative setting. They commonly resolve spontaneously. However, occasionally, they may continually progress to fatal arrhythmias or cause complications. Therefore, prompt and appropriate management is important.

CASE SUMMARY

A 46-year-old female patient diagnosed with cervical C6-7 radiculopathy characterized by decreased sensation in the right third, fourth and fifth fingers underwent C6-7 anterior cervical disc fusion surgery. Electrocardiography showed PSVT and ventricular tachycardia during C6-7 disc retraction. However, the patient remained stable. Initial treatment with esmolol and lidocaine for ventricular tachycardia was ineffective. Carotid massage and Valsalva maneuver were attempted but PSVT did not resolve. The surgery was paused, and the patient's fraction of inspired oxygen was set to 100%. Adenosine was administered for pharmacological management of PSVT. The arrhythmia temporarily resolved. However, it then transformed into AF. Diltiazem was administered, which briefly decreased blood pressure, which immediately recovered. Surgery resumed while the patient was in normal sinus rhythm. She was discharged safely on postoperative day 6 without complications or abnormalities. Currently, she is living a healthy life without arrhythmia recurrence.

CONCLUSION

Ganglia associated with cardiac arrhythmias in the surgical site should be identified during cervical spine surgery.

Imperatorin Improves Obesity-Induced Cardiac Sympathetic Nerve Injury Mediated by P2X4 Receptor in Stellate Sympathetic Ganglion

Obesity can activate the inflammatory signal pathway, induce in the body a state of chronic inflammation, and increase the excitability of the sympathetic nervous system, which may induce sympathetic neuropathic injury. The stellate sympathetic ganglia (SG) can express the P2X4 receptor, and the abnormal expression of the P2X4 receptor is related to inflammation. Imperatorin (IMP) is a kind of furan coumarin plant which has anti-inflammatory effects. This project aimed to investigate whether IMP can affect the expression of P2X4 receptors in the SG of obese rats to display a protective effect from high-fat-triggered cardiac sympathetic neuropathic injury. Molecular docking through homology modelling revealed that IMP had good affinity for the P2X4 receptor. Our results showed that compared with the normal group, the administration of IMP or P2X4 shRNA decreased sympathetic excitement; reduced the serum levels of triglyceride, total cholesterol, and lactate dehydrogenase; downregulated the expression of P2X4 receptors in SG; and inhibited the expression of inflammatory factors in the SG and serum of obese rats significantly. In addition, the expression of factors associated with the cell pyroptosis GSDMD, caspase-1, NLRP-3, and IL-18 in obese rats were significantly higher than those of the normal rats, and such effects were decreased after treatment with IMP or P2X4 shRNA. Furthermore, IMP significantly reduced the ATP-activated currents in HEK293 cells transfected with P2X4 receptor. Thus, the P2X4 receptor may be a key target for the treatment of obesity-induced cardiac sympathetic excitement. IMP can improve obesity-induced cardiac sympathetic excitement, and its mechanism of action may be related to the inhibition of P2X4 receptor expression and activity in the SG, suppression of cellular pyroptosis in the SG, and reduction of inflammatory factor levels.

Association of Depressive and Somatic Symptoms with Heart Rate Variability in Patients with Traumatic Brain Injury

Depressive and somatic symptoms are common after traumatic brain injury (TBI). Depression after TBI can relate to worsened cognitive functioning, functional impairment, higher rates of suicide attempts, and larger health care costs. Heart rate variability (HRV) represents the activity of the autonomic nervous system (ANS), which regulates almost all vascular, visceral, and metabolic functions. Several studies show a correlation between HRV, depression, and somatic symptoms in other diseases. However, studies on autonomic dysfunction, depression, and somatic symptoms in TBI patients are lacking. This study investigated the association between reduced ANS function, depression, and somatic symptoms in TBI patients. We retrospectively recruited 136 TBI patients who underwent 24 h ambulatory Holter electrocardiography to measure autonomic dysfunction within 1 month of onset. Patients who used BDI and PHQ-15 to evaluate depressive and somatic symptoms were included. Using Pearson's correlation analysis and multiple linear regression, the association between HRV parameters and BDI and PHQ-15 was determined. The HRV parameters and BDI and PHQ-15 showed statistical significance. In addition, HRV was shown to be a significantly associated factor of BDI and PHQ-15. HRV was associated with depressive and somatic symptom severity in TBI patients. Additionally, autonomic dysfunction may serve as an associated factor of depressive and somatic symptoms in patients with TBI.