Background: The cholinergic anti-inflammatory pathway (CAP) has been widely studied to modulate the immune response. Current stimulating strategies are invasive or imprecise. Noninvasive low-intensity pulsed ultrasound (LIPUS) has become increasingly appreciated for targeted neuronal modulation. However, its mechanisms and physiological role on myocarditis remain poorly defined. Methods: The mouse model of experimental autoimmune myocarditis was established. Low-intensity pulsed ultrasound was targeted at the spleen to stimulate the spleen nerve. Under different ultrasound parameters, histological tests and molecular biology were performed to observe inflammatory lesions and changes in immune cell subsets in the spleen and heart. In addition, we evaluated the dependence of the spleen nerve and cholinergic anti-inflammatory pathway of low-intensity pulsed ultrasound in treating autoimmune myocarditis in mice through different control groups. Results: The echocardiography and flow cytometry of splenic or heart infiltrating immune cells revealed that splenic ultrasound could alleviate the immune response, regulate the proportion and function of CD4+ Treg and macrophages by activating cholinergic anti-inflammatory pathway, and finally reduce heart inflammatory injury and improve cardiac remodeling, which is as effective as an acetylcholine receptor agonists GTS-21. Transcriptome sequencing showed significant differential expressed genes due to ultrasound modulation. Conclusions: It is worth noting that the ultrasound therapeutic efficacy depends greatly on acoustic pressure and exposure duration, and the effective targeting organ was the spleen but not the heart. This study provides novel insight into the therapeutic potentials of LIPUS, which are essential for its future application. Graphical

Background: Doxorubicin-induced cardiotoxicity remains a major clinical challenge. The intricate immunomodulatory pathways responsible for cardiac damage remain incompletely defined. Cardiac CCR2 ⁺ MHC II ^high macrophages have emerged as a critical subset contributing to inflammatory cardiovascular injury. However, the precise exacerbating role and mechanisms by which these macrophages contribute to doxorubicin-induced myocardial injury remain elusive. Metabolic reprogramming significantly influences the transition of macrophages to an inflammatory phenotype, and pyruvate kinase M2 (PKM2), a key rate-limiting enzyme of glucose metabolism, may be a possible regulatory node and a promising therapeutic target for intervention. Methods: Doxorubicin-induced cardiotoxicity model was established in C57BL6/J mice. This model was utilized to assess the dynamic change relationship between cardiac function, cardiac CCR2 ⁺ MHC II ^high macrophages, and myocardial injury remodeling. Also, the crosstalk between macrophage phenotypic switching and cardiomyocyte damage was explored in vitro . We further investigated the role of PKM2 in CCR2 ⁺ macrophage metabolic reprogramming and the therapeutic potential of using Shikonin to inhibit PKM2 to ameliorate cardiac injury. Moreover, peripheral blood cells from patients receiving Doxorubicin chemotherapy were used to verify the changes in PKM2 in macrophages, which revealed the role of metabolic reprogramming in pro-inflammatory macrophages. Results: CCR2 ⁺ MHC II ^high macrophages may play a crucial role in exacerbating sustained cardiotoxicity caused by Doxorubicin. In vitro studies have shown that PKM2 facilitates the transition of macrophages into a pro-inflammatory CCR2 ⁺ phenotype. The phosphorylation of PKM2 mechanistically contributes to the metabolic reprogramming of these pro-inflammatory CCR2 ⁺ macrophages. In vivo and in vitro experiments have demonstrated that pharmacological inhibition of PKM2 with Shikonin mitigates doxorubicin-induced cardiotoxicity. Conclusion: Our results reveal a pivotal metabolic regulator of cardiac CCR2 ⁺ MHC II ^high macrophages through metabolic reprogramming. Targeting PKM2 could offer a novel approach for mitigating Doxorubicin-induced myocardial inflammatory damage. Exploring the impact of CCR2 ⁺ macrophages on exacerbating myocardial injury sheds new light on the interplay between aberrant immune response of macrophage and Doxorubicin-induced myocarditis.

Arrhythmia is a clinically common cardiovascular disorder characterized by high incidence and a strong association with sudden cardiac death, posing a significant threat to patient survival and quality of life. The pathogenesis of arrhythmia is complex, and abnormal autonomic nervous system (ANS) modulation, as one of the causes, offers new perspectives and therapeutic targets for arrhythmia treatment. This review discusses the mechanisms by which abnormal ANS modulation leads to arrhythmias and strategies for treating arrhythmias through ANS modulation.