Light-emitting diode therapy protects against ventricular arrhythmias by neuro-immune modulation in myocardial ischemia and reperfusion rat model

Autophagy-enhanced nanosonosensitizer mediated sonodynamic therapy for post-myocardial infarction neuromodulation and arrhythmia prevention

Rationale: Sympathetic hyperactivation and neuroinflammation are the main triggers of malignant ventricular arrhythmias (VAs) after myocardial infarction (MI). Previous studies proved that photothermal therapy (PTT) and photodynamic therapy (PDT) could reduce MI-induced VAs by inhibiting neuroinflammation. However, the limited penetration depth and potential phototoxicity of phototherapy impose constraints on its further application. As a treatment strategy derived from phototherapy, sonodynamic therapy (SDT) offers exceptional advantages, including excellent penetration capability, temporal-spatial controllability, superior efficacy and minimal side effects. Therefore, it is worthwhile to investigate the effects of sonodynamic modulation on neuroinflammation and arrhythmia prevention. Methods: We designed a long-wavelength emissive sonosensitizer (named BBTD-TPA) based on donor-acceptor-donor scaffold. Subsequently, the compound was encapsulated in DSPE-PEG5000 to form BBTD-TPA nanoparticles (NPs). In vitro experiments were conducted to determine the optimal concentration of BBTD-TPA NPs-mediated SDT and to verify the effects and pathways on autophagy in BV2 cells. The distribution and metabolism of BBTD-TPA NPs in vivo were assessed by NIR-II fluorescence imaging. Finally, in vivo studies were performed to assess the effect of BBTD-TPA NPs-mediated SDT on post-MI sympathetic neuroinflammation and the occurrence of VAs. Results: In vitro studies demonstrated that BBTD-TPA NPs combined with LIFU could promote microglial autophagy via the ROS-AMPK-mTOR pathway. BBTD-TPA NPs were further microinjected into the paraventricular nucleus (PVN), real-time NIR-II fluorescence imaging showed that BBTD-TPA NPs could remain in the PVN for up to 12 h and be metabolized through the liver and kidney. Further in vivo results verified that BBTD-TPA NPs-mediated SDT could inhibit sympathetic nervous activity, and inflammatory responses, thus preventing MI-induced VAs. Conclusion: BBTD-TPA NPs-mediated SDT can promote microglial autophagy and inhibit sympathetic neuroinflammation, thus reducing MI-induced VAs. The current research may inspire a novel strategy for neuromodulation and arrhythmia prevention, providing broader prospects for clinical translation of nanomedical technology.

Long-term transcranial ultrasound stimulation regulates neuroinflammation to ameliorate post-myocardial infarction cardiac arrhythmia and remodeling

BACKGROUND

Sympathetic overactivation and neuroinflammation in the paraventricular nucleus (PVN) are crucial factors in post-myocardial infarction (MI) cardiac remodeling and ventricular arrhythmias (VAs). Prior study has indicated that low-intensity focused ultrasound stimulation could attenuate sympathetic neuroinflammation within the PVN to prevent the occurrence of VAs in an acute MI model. Meanwhile, the cGAS-STING pathway has shown potential to ameliorate the neuroinflammatory response. However, the effect and mechanisms of long-term transcranial ultrasound stimulation (LTUS) for modulating neuroinflammation in the chronic stage of MI remain unclear.

OBJECTIVE

This study aimed to ascertain whether LTUS could mitigate post-MI neuroinflammation and improve cardiac arrhythmia and remodeling through the cGAS-STING pathway.

METHODS

Thirty-six SD rats were equally randomized to the sham group (pseudo-MI modeling), chronic MI group (MI modeling), and LTUS group (MI modeling and long-term ultrasound stimulation). Transcranial ultrasound stimulation (15 min/d) was conducted on the PVN for 4 consecutive weeks. After 4-week intervention, echocardiography, electrophysiologic experiments, and histopathologic staining were performed to assess the role of LTUS on post-MI neuroinflammation and cardiac remodeling.

RESULTS

The results indicated that LTUS significantly facilitated microglial M1 to M2 polarization through the cGAS-STING signaling pathway within the PVN. Furthermore, LTUS inhibited MI-induced sympathetic neuroinflammation, thereby improving cardiac dysfunction, ameliorating cardiac remodeling, and reducing VA inducibility.

CONCLUSION

Long-term ultrasound stimulation of the PVN was found to alleviate post-MI neuroinflammation and to improve cardiac remodeling, which might inspire novel insights and clinical strategies for noninvasive neuromodulation and the treatment of post-MI VAs.

Mitochondria-targeted sonodynamic modulation of neuroinflammation to protect against myocardial ischemia‒reperfusion injury

Sympathetic hyperactivation and inflammatory responses are the main causes of myocardial ischemia‒reperfusion (I/R) injury and myocardial I/R-related ventricular arrhythmias (VAs). Previous studies have demonstrated that light-emitting diodes (LEDs) could modulate post-I/R neuroinflammation, thus providing protection against myocardial I/R injury. Nevertheless, further applications of LEDs are constrained due to the low penetration depth (<1 cm) and potential phototoxicity. Low-intensity focused ultrasound (LIFU), an emerging noninvasive neuromodulation strategy with deeper penetration depth (∼10 cm), has been confirmed to modulate sympathetic nerve activity and inflammatory responses. Sonodynamic therapy (SDT), which combines LIFU with sonosensitizers, confers additional advantages, including superior therapeutic efficacy, precise localization of neuronal modulation and negligible side effects. Herein, LIFU and SDT were introduced to modulate post-myocardial I/R neuroinflammation to protect against myocardial I/R injury. The results indicated that LIFU and SDT inhibited sympathetic neural activity, suppressed the activation of astrocytes and microglia, and promoted microglial polarization towards the M2 phenotype, thereby attenuating myocardial I/R injury and preventing I/R-related malignant VAs. These insights suggest that LIFU and SDT inspire a noninvasive and efficient neuroinflammatory modulation strategy with great clinical translation potential thus benefiting more patients with myocardial I/R in the future. STATEMENT OF SIGNIFICANCE: Myocardial ischemia-reperfusion (I/R) may cause I/R injury and I/R-induced ventricular arrhythmias. Sympathetic hyperactivation and inflammatory response play an adverse effect in myocardial I/R injury. Previous studies have shown that light emitting diode (LED) can regulate I/R-induced neuroinflammation, thus playing a myocardial protective role. However, due to the low penetration depth and potential phototoxicity of LED, it is difficult to achieve clinical translation. Herein, we introduced sonodynamic modulation of neuroinflammation to protect against myocardial I/R injury, based on mitochondria-targeted nanosonosensitizers (CCNU980 NPs). We demonstrated that sonodynamic modulation could promote microglial autophagy, thereby preventing myocardial I/R injury and I/R-induced ventricular arrhythmias. This is the first example of sonodynamic modulation of myocardial I/R-induced neuroinflammation, providing a novel strategy for clinical translation.

Low-intensity pulsed ultrasound treatment mitigates ventricular arrhythmias via inhibiting microglia-mediated neuroinflammation in heart failure rat model

BACKGROUND

Sympathetic overactivation plays an important role in heart failure (HF)-induced ventricular arrhythmias (VAs). Microglia-mediated neuroinflammation could contribute to sympathetic overactivation. A previous study demonstrated that low-intensity pulsed ultrasound (LIPUS) could inhibit neuroinflammation. However, whether LIPUS could attenuate HF-induced VAs via inhibiting microglia-mediated neuroinflammation remains largely unknown.

METHODS

Forth Sprague-Dawley male rats were averagely randomized into four groups: CTL (control) group, CTL + LIPUS group, HF group and HF + LIPUS. Surgical ligation of the coronary artery was used for induction of HF. In vivo electrophysiological study was performed to check VAs susceptibility. Left stellate ganglion (LSG) neural activity and heart rate variability (HRV) were used to test sympathetic nerve activity.

RESULTS

Compared to the HF group, LIPUS treatment significantly ameliorated HF-induced cardiac hypertrophy, fibrosis, and dysfunction. In addition, LIPUS treatment markedly inhibited HF-induced VAs susceptibility and reversed gap junction remodeling. LIPUS treatment obviously inhibited microglial activation and neuroinflammation in PVN, sympathetic hyperactivity in the LSG and proinflammatory cytokines releases in the ventricle. P2X7/NLRP3 signaling pathway may be involved in the anti-arrhythmic effect of LIPUS treatment following HF.

CONCLUSIONS

Our data demonstrated that LIPUS treatment protected against HF-induced VAs via alleviating microglia-mediated neuroinflammation, sympathetic overactivation and proinflammatory cytokines releases through inhibiting P2X7/NLRP3 signaling. This study provides novel insight into the therapeutic potential of LIPUS.

Renal denervation alleviates chronic obstructive sleep apnea-induced atrial fibrillation via inhibition of atrial fibrosis and sympathetic hyperactivity

OBJECTIVE

Previous studies have reported that renal denervation (RDN) prevents the occurrence of atrial fibrillation (AF) related to obstructive sleep apnea (OSA). However, the effect of RDN on chronic OSA (COSA)-induced AF is still unclear.

METHODS

Healthy beagle dogs were randomized into the OSA group (sham RDN + OSA), OSA-RDN group (RDN + OSA), and CON group (sham RDN + sham OSA). The COSA model was built via repeated apnea and ventilation rounds for 4 h each day lasting 12 weeks, and RDN was employed after 8 weeks of modeling. All dogs were implanted Reveal LINQ™ to detect spontaneous AF and AF burden. Circulating levels of norepinephrine, angiotensin II, and interleukin-6 were determined at baseline and end of the study. In addition, measurements of the left stellate ganglion, AF inducibility, and effective refractory period were conducted. The bilateral renal artery and cortex, left stellate ganglion, and left atrial tissues were collected for molecular analysis.

RESULTS

Of 18 beagles, 6 were randomized to each of the groups described above. RDN remarkably attenuated ERP prolongation and AF episodes and duration. RDN markedly suppressed the LSG hyperactivity and atrial sympathetic innervation, decreased the serum concentrations of Ang II and IL-6, further inhibited fibroblast-to-myofibroblast transformation via the TGF-β1/Smad2/3/α-SMA pathway, and reduced the expression of MMP-9, thus decreasing OSA-induced AF.

CONCLUSIONS

RDN may reduce AF by inhibiting sympathetic hyperactivity and AF in a COSA model.

Transient cardiac electrophysiological changes in a rat model of subarachnoid haemorrhage: a brain-heart interaction

AIMS

Subarachnoid haemorrhage (SAH) is one of the causes of sudden cardiac death (SCD). However, the time course of ventricular arrhythmias and potential mechanisms responsible for this effect after SAH remain unknown.

OBJECTIVE

This study aims to investigate the effect of SAH on ventricular electrophysiological changes and its potential mechanisms in long-term phase.

METHODS AND RESULTS

We examined the ventricular electrophysiological remodelling and potential mechanisms in a Sprague Dawley rat model of SAH at six time points (baseline, and Days 1, 3, 7, 14 and 28) and explored the potential mechanisms. We measured the ventricular effective refractory period (ERP), ventricular fibrillation threshold (VFT) and left stellate ganglion (LSG) activity at different time points before and after SAH. We also detected neuropeptide Y (NPY) levels in plasma and myocardial tissues by enzyme-linked immunosorbent assay, and quantified NPY 1 receptor (NPY1R) protein and mRNA expression levels by western blotting and quantitative real-time reverse transcription-polymerase chain reaction, respectively. Subarachnoid haemorrhage gradually prolonged QTc intervals, shortened ventricular ERP and reduced VFT during the acute phase, peaking at Day 3. However, no significant changes were observed from Days 14 to 28 compared to Day 0. Subarachnoid haemorrhage gradually increased LSG activity, increased NPY concentrations and up-regulated NPY1R expression in the acute phase of SAH, peaking at Day 3. However, no significant variations were found from Days 14 to 28 compared to Day 0.

CONCLUSION

Subarachnoid haemorrhage increases the transient susceptibility of VAs in the acute phase, and the underlying mechanisms for this response included increased sympathetic activity and up-regulated NPY1R expression.

A Novel Polysaccharide From Chuanminshen violaceum and Its Protective Effect Against Myocardial Injury

We isolated and purified a novel polysaccharide from the root of Chuanminshen violaceum, namely, Chuanminshen violaceumis polysaccharide (CVP) and confirmed its structure and molecular weight. Furthermore, in vivo experiment, CVP’s protective effect against myocardial ischemia-reperfusion (I/R) injury in mice was evidenced by significantly reducing I/R-induced myocardial infarction (MI) size, decreasing the secretion of heart damage biomarkers, and improving cardiac function. Then, the myocardial anoxia/reoxygenation (A/R) injury model was established to mimic reperfusion injury. Noticeably, ferroptosis was the major death manner for A/R-damaged H9c2 cells. Meanwhile, CVP significantly inhibited ferroptosis by decreasing intracellular Fe²⁺ level, enhancing GPX4 expression, and suppressing lipid peroxidation to confront A/R injury. In conclusion, CVP, with a clear structure, ameliorated I/R injury by inhibiting ferroptosis.

Enhanced atrial internal-external neural remodeling facilitates atrial fibrillation in the chronic obstructive sleep apnea model

OBJECTIVE

Autonomic imbalance plays a crucial role in obstructive sleep apnea (OSA) associated atrial fibrillation (AF). Here, we investigated the potential neural mechanism of AF induced by OSA.

METHODS

Ten dogs were divided into control group (n = 5) and OSA group (n = 5). The chronic OSA model was established by repeat apnea-ventilation cycles for 4 hours a day for 12 weeks. During the process of model establishment, arterial blood gases, atrial effective refractory period (AERP), AF inducibility, normalized low-frequency power (LFnu), normalized high-frequency power (HFnu), and LFnu/ HFnu were evaluated at baseline, 4th week, 8th week, and 12th week. Nerve activities of left stellate ganglion (LSG) and left vagal nerve(LVN) were recorded. Tyrosine hydroxylase(TH), choline acetyltransferase(CHAT), PGP9.5, nerve growth factor(NGF), and c-Fos were detected in the left atrium, LSG, and LVN by immunohistochemistry and western blot. Moreover, high-frequency stimulations of LSG and LVN were conducted to observe the AF inducibility.

RESULTS

Compared with the control group, the OSA group showed significantly enhanced neural activity of the LSG, increased AF inducibility, and shortened AERP. LFnu and LFnu/HFnu were markedly increased in the OSA group, while no significant difference in HFnu was observed. TH-positive and PGP9.5-positive nerve densities were significantly increased in the LSG and left atrium. Additionally, the protein levels of NGF, c-Fos, and PGP9.5 were upregulated both in the LSG and left atrium. AF inducibility was markedly increased under LSG stimulation without a stimulus threshold change in the OSA group.

CONCLUSIONS

OSA significantly enhanced LSG and left atrial neural remodeling, and hyperactivity of LSG may accelerate left atrial neural remodeling to increase AF inducibility.

Non-invasive Autonomic Neuromodulation Is Opening New Landscapes for Cardiovascular Diseases

Autonomic imbalance plays a crucial role in the genesis and maintenance of cardiac disorders. Approaches to maintain sympatho-vagal balance in heart diseases have gained great interest in recent years. Emerging therapies However, certain types of emerging therapies including direct electrical stimulation and nerve denervation require invasive implantation of a generator and a bipolar electrode subcutaneously or result in autonomic nervous system (ANS) damage, inevitably increasing the risk of complications. More recently, non-invasive neuromodulation approaches have received great interest in ANS modulation. Non-invasive approaches have opened new fields in the treatment of cardiovascular diseases. Herein, we will review the protective roles of non-invasive neuromodulation techniques in heart diseases, including transcutaneous auricular vagus nerve stimulation, electromagnetic field stimulation, ultrasound stimulation, autonomic modulation in optogenetics, and light-emitting diode and transcutaneous cervical vagus nerve stimulation (gammaCore).

Silenced SOX2-OT alleviates ventricular arrhythmia associated with heart failure by inhibiting NLRP3 expression via regulating miR-2355-3p

Background

Nucleotide‐binding oligomerization domain‐like receptor family pyrin domain containing 3 (NLRP3) inflammasomes are the most important factors in ventricular arrhythmia associated with heart failure (VA‐HF). However, how the relationship between lncRNA and NLRP3 inflammasomes is regulated in VA‐HF has not been investigated in detail. Thus, we aimed to determine the effects of SOX2‐overlapping transcripts (SOX2‐OT) by targeting NLRP3 in rats with VA‐HF.

Methods

We established rats (SPF, male, weight: 240 ± 10 g) with VA‐HF by aortic coarctation and constant‐current stimulation, then injected them with small interfering SOX2‐OT and anti‐miR‐2355‐3p. Six weeks later, SOX2‐OT and miR‐2355‐3p expression was measured using the quantitative reverse transcriptase‐polymerase chain reaction and NLRP3, ASC, caspase‐1, IL‐1β, and TGF‐β1 expression were measured by Western blot analysis; the ventricular chambers were histopathologically analyzed by staining with hematoxylin and eosin, Masson trichrome, and Picro Sirius Red and reactive oxygen species (ROS) levels were assessed by flow cytometry. The targeting relationship between miR‐2355‐3p and SOX2‐OT or NLRP3 was verified using dual‐luciferase reporter gene assays.

Results

The expression of SOX2‐OT and levels of NLRP3 inflammasomes gradually increased in normal rats, and in those with heart failure and with VA‐HF. Silencing SOX2‐OT expression inhibited NLRP3, ASC, caspase‐1, IL‐1β, and TGF‐β1 expression and ROS production, reduced the degrees of cardiomyocyte necrosis and fibrosis and alleviated cardiac dysfunction in rats with VA‐HF. MicroR‐2355‐3p can bind the SOX2‐OT and the 3′‐untranslated region of NLRP3. Inhibiting miR‐2355‐3p reversed the effect of SOX2‐OT in rats with VA‐HF.

Conclusions

Silencing SOX2‐OT alleviated cardiac dysfunction in rats by reducing the activation of NLRP3 inflammasomes via regulating miR‐2355‐3p.

MicroRNA-668-3p Protects Against Oxygen-Glucose Deprivation in a Rat H9c2 Cardiomyocyte Model of Ischemia-Reperfusion Injury by Targeting the Stromal Cell-Derived Factor-1 (SDF-1)/CXCR4 Signaling Pathway

Background

Ischemia-reperfusion injury (IRI) results from the restoration of blood supply to ischemic organs, including the heart. Expression of microRNA-668-3p (miR-668-3p) is known to protect the kidney from IRI. This study aimed to investigate the role of miR-668-3p in oxygen-glucose deprivation (OGD) in a rat H9c2 cardiomyocyte model of IRI.

Material/Methods

Rat H9c2 cardiomyocytes were cultured in glucose-free Dulbecco’s modified Eagle’s medium (DMEM) under anaerobic conditions, followed by oxygenation, to create the OGD model of IRI. The luciferase reporter assay evaluated the interaction between stromal cell-derived factor-1 (SDF-1), or CXC motif chemokine 12 (CXCL12), and miR-668-3p. Protein and mRNA levels of SDF-1, CXCR4, Bcl2, Bax, cleaved caspase-3, endothelial nitric oxide synthase (eNOS), and phosphorylated endothelial nitric oxide synthase (p-eNOS) were analyzed by Western blot and quantitative reverse transcription-polymerase chain reaction (RT-qPCR), and apoptosis were assessed by flow cytometry. Enzyme-linked immunosorbent assay (ELISA) measured reactive oxygen species (ROS), including malondialdehyde (MDA), nitric oxide (NO), p-eNOS, and the inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and monocyte chemoattractant protein-1 (MCP-1) in H9c2 cell supernatants.

Results

In the OGD rat H9c2 cardiomyocyte model of IRI, miR-668-3p levels were reduced. Overexpression of miR-668-3p inhibited SDF-1, CXCR4, the expression of inflammatory cytokines, markers of oxidative stress, and p-eNOS. The overexpression of SDF-1 reversed these findings. Overexpression of SDF-1 promoted cell apoptosis, which was reduced by miR-668-3p.

Conclusions

In the OGD rat H9c2 cardiomyocyte model of IRI, miR-668-3p suppressed mediators of inflammation and oxidative stress and enhanced cell viability through the SDF-1/CXCR4 signaling pathway.