Non-excitatory electrical stimulation attenuates myocardial infarction via homeostasis of calcitonin gene-related peptide in myocardium

Morphine timing-dependent modulation of TRPV1 phosphorylation correlates with differential morphine effects on myocardial ischemia/reperfusion injury

Opioids are used for pain relief in patients suffering from acute myocardial ischemia or infarction. Clinical and laboratory studies demonstrate that morphine treated patients or the experimental animal model suffering acute myocardial ischemia and reperfusion, may worsen myocardial viability. As transient receptor potential vanilloid 1 (TRPV1) plays important roles in pain sensation and cardio-protection, we query whether opioids may exacerbate myocardial viability via interaction with TRPV1 activity in the pain relief. We found the co-expressions of TRPV1 and opioid μ, δ and κ receptors in adult rat cardiomyocytes. Intravenous injection of morphine (0.3 mg/kg) at 20 min after induction of myocardial ischemia, in the rat model of acute myocardial ischemia and reperfusion, induced significant reduction of phosphorylated TRPV1 (p-TRPV1) in the ventricular myocardium and increase in serum cardiac troponin I (cTnI), compared with the ischemia/reperfusion controls (all P < 0.05). The effects of morphine were completely reversed by selective opioid μ, δ and κ receptor antagonists. While significant upregulation of p-TRPV1 (P < 0.05) and improvement of ±dP/dt max (all P < 0.05) were detected in the animals giving the same dose of morphine before induction of myocardial ischemia. The changes in p-TRPV1 correlate with the alterations of cTnI (r = -0.5840, P = 0.0283) and ±dP/dt max (r = 0.8084, P = 0.0005 and r = -0.8133, P = 0.0004, respectively). The findings of this study may indicate that potentiation and attenuation of TRPV1 sensitivity correlate with the improvement of the cardiac performance and the aggravation of myocardial viability, respectively, by giving morphine before and during myocardial ischemia and reperfusion.

E-cardiac patch to sense and repair infarcted myocardium

Conductive cardiac patches can rebuild the electroactive microenvironment for the infarcted myocardium but their repair effects benefit by carried seed cells or drugs. The key to success is the effective integration of electrical stimulation with the microenvironment created by conductive cardiac patches. Besides, due to the concerns in a high re-admission ratio of heart patients, a remote medicine device will underpin the successful repair. Herein, we report a miniature self-powered biomimetic trinity triboelectric nanogenerator with a unique double-spacer structure that unifies energy harvesting, therapeutics, and diagnosis in one cardiac patch. Trinity triboelectric nanogenerator conductive cardiac patches improve the electroactivity of the infarcted heart and can also wirelessly monitor electrocardiosignal to a mobile device for diagnosis. RNA sequencing analysis from rat hearts reveals that this trinity cardiac patches mainly regulates cardiac muscle contraction-, energy metabolism-, and vascular regulation-related mRNA expressions in vivo. The research is spawning a device that truly integrates an electrical stimulation of a functional heart patch and self-powered e-care remote diagnostic sensor.

Research Progress of Electrical Stimulation in Ischemic Heart Disease

Ischemic heart disease (IHD) is a considerable health burden worldwide with high mortality and morbidity. Treatments for IHD are mainly focused on decreasing oxygen demand or increasing myocardial oxygen supply, including pharmacological, interventional, and surgical treatment, but there are also some limitations. Therefore, it is important to find a simple, effective, and economical treatment. As non-invasive and safe physiotherapy, electrical stimulation (ES) has a promising application in the treatment of IHD. Current studies suggest that ES can affect the occurrence and development of IHD by promoting angiogenesis, regulating autophagy and apoptosis, inhibiting the inflammatory response and oxidative stress. In this review, we focus predominantly on the mechanism of ES and the current progress of ES therapy in IHD, furthermore, give a brief introduction to the forms of ES in clinical application.

Preservation of CGRP in myocardium attenuates development of cardiac dysfunction in diabetic rats

BACKGROUND

Calcitonin gene-related peptide (CGRP) plays an important role in cardiovascular regulation, which was found reduced in serum of diabetic patients. To test the hypothesis that lack of CGRP in myocardium is associated with diabetic cardiac dysfunction, which may be improved by preservation of CGRP in diabetic rats.

METHODS AND RESULTS

Diabetes was induced in male Sprague-Dawley rats by streptozotocin (50mg/kg). Two groups of the diabetic rats, one fed with standard laboratory chew and another with the laboratory food plus hot pepper (containing 0.0174% of capsaicin), to stimulate production and release of CGRP. Cardiac functions were evaluated by measurements of intraventricular pressures after 8weeks of development of diabetes. Transient receptor potential vanilloid type 1 (TRPV1), CGRP, β1-adreneregic receptor and norepinephrine were analyzed. Significantly lower levels of TRPV1 and CGRP were detected in the thoracic dorsal root ganglia (DRG) and myocardium of the diabetic animals, along with significant decline in left ventricular systolic pressure (by 24%) and heart rate (by 25%) and increase of the end-diastolic pressure (by 83%) with obvious reduction of CGRP in the DRG, by 41%, the myocardium (by 30%) and the serum (by 20%). The cardiac performance, the TRPV1 and the CGRP in the diabetic animals fed with hot pepper were well preserved. No any significant change in β1-adreneregic receptor and norepinephrine was detected.

CONCLUSION

The findings may suggest a novel mechanism underlying diabetic cardiac dysfunctions via impairing TRPV1-CGRP pathway in myocardium. Preservation of the TRPV1-CGRP mechanism may prevent the development of cardiac dysfunction in diabetes.