A systematic review and meta-analysis of cold exposure and cardiovascular disease outcomes.

Background: Cold exposure has been considered an essential risk factor for the global disease burden, while its role in cardiovascular diseases is still underappreciated. The increase in frequency and duration of extreme cold weather events like cold spells makes it an urgent task to evaluate the effects of ambient cold on different types of cardiovascular disease and to understand the factors contributing to the population's vulnerability. Methods: In the present systematic review and meta-analysis, we searched PubMed, Scopus, and Cochrane. We included original research that explored the association between cold exposure (low temperature and cold spell) and cardiovascular disease outcomes (mortality and morbidity). We did a random-effects meta-analysis to pool the relative risk (RR) of the association between a 1°C decrease in temperature or cold spells and cardiovascular disease outcomes. Results: In total, we included 159 studies in the meta-analysis. As a result, every 1°C decrease in temperature increased cardiovascular disease-related mortality by 1.6% (RR 1.016; [95% CI 1.015-1.018]) and morbidity by 1.2% (RR 1.012; [95% CI 1.010-1.014]). The most pronounced effects of low temperatures were observed in the mortality of coronary heart disease (RR 1.015; [95% CI 1.011-1.019]) and the morbidity of aortic aneurysm and dissection (RR 1.026; [95% CI 1.021-1.031]), while the effects were not significant in hypertensive disease outcomes. Notably, we identified climate zone, country income level and age as crucial influential factors in the impact of ambient cold exposure on cardiovascular disease. Moreover, the impact of cold spells on cardiovascular disease outcomes is significant, which increased mortality by 32.4% (RR 1.324; [95% CI 1.2341.421]) and morbidity by 13.8% (RR 1.138; [95% CI 1.015-1.276]). Conclusion: Cold exposure could be a critical risk factor for cardiovascular diseases, and the cold effect varies between disease types and climate zones. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO, identifier: CRD42022347247.

Inflammatory Response: A Crucial Way for Gut Microbes to Regulate Cardiovascular Diseases.

Gut microbiota is the largest and most complex microflora in the human body, which plays a crucial role in human health and disease. Over the past 20 years, the bidirectional communication between gut microbiota and extra-intestinal organs has been extensively studied. A better comprehension of the alternative mechanisms for physiological and pathophysiological processes could pave the way for health. Cardiovascular disease (CVD) is one of the most common diseases that seriously threatens human health. Although previous studies have shown that cardiovascular diseases, such as heart failure, hypertension, and coronary atherosclerosis, are closely related to gut microbiota, limited understanding of the complex pathogenesis leads to poor effectiveness of clinical treatment. Dysregulation of inflammation always accounts for the damaged gastrointestinal function and deranged interaction with the cardiovascular system. This review focuses on the characteristics of gut microbiota in CVD and the significance of inflammation regulation during the whole process. In addition, strategies to prevent and treat CVD through proper regulation of gut microbiota and its metabolites are also discussed.

DPP3: From biomarker to therapeutic target of cardiovascular diseases.

Cardiovascular disease is the leading cause of death globally among non-communicable diseases, which imposes a serious socioeconomic burden on patients and the healthcare system. Therefore, finding new strategies for preventing and treating cardiovascular diseases is of great significance in reducing the number of deaths and disabilities worldwide. Dipeptidyl peptidase 3 (DPP3) is the first zinc-dependent peptidase found among DPPs, mainly distributes within the cytoplasm. With the unique HEXXGH catalytic sequence, it is associated with the degradation of oligopeptides with 4 to 10 amino acids residues. Accumulating evidences have demonstrated that DPP3 plays a significant role in almost all cellular activities and pathophysiological mechanisms. Regarding the role of DPP3 in cardiovascular diseases, it is currently mainly used as a biomarker for poor prognosis in patients with cardiovascular diseases, suggesting that the level of DPP3 concentration in plasma is closely linked to the mortality of diseases such as cardiogenic shock and heart failure. Interestingly, it has been reported recently that DPP3 regulates blood pressure by interacting with the renin-angiotensin system. In addition, DPP3 also participates in the processes of pain signaling, inflammation, and oxidative stress. But the exact mechanism by which DPP3 affects cardiovascular function is not clear. Hence, this review summarizes the recent advances in the structure and catalytic activity of DPP3 and its extensive biological functions, especially its role as a therapeutic target in cardiovascular diseases. It will provide a theoretical basis for exploring the potential value of DPP3 as a therapeutic target for cardiovascular diseases.

Oxidative stress in the RVLM mediates sympathetic hyperactivity induced by circadian disruption.

Circadian rhythm plays a significant role in maintaining the function of the cardiovascular system. Emerging studies have demonstrated that circadian disruption enhances the risk of cardiovascular diseases by activating the sympathetic nervous system; however, the underlying mechanisms remain unknown. Therefore, this study aimed to clarify the role of oxidative stress in the rostral ventrolateral medulla (RVLM) in sympathetic hyperactivity induced by circadian disruption. Rats were randomly divided into two groups: the normal light and dark (LD) group and the circadian disruption (CD) group. Sympathetic nerve activity of rats was assessed by recording renal sympathetic nerve activity (RSNA) and indirect methods such as plasma level of norepinephrine (NE). The level of oxidative stress in the RVLM was detected by dihydroethidium probes. Moreover, the expression levels of the oxidative stress-related proteins in the RVLM were detected by Western blotting. Circadian disruption significantly increased blood pressure (BP), RSNA, and plasma levels of NE. Compared to the LD group, the CD group exhibited a more significant depressor response to i.v. hexamethonium bromide, a ganglionic blocker. Furthermore, the reactive oxygen species (ROS) production in the RVLM of rats with circadian disruption was significantly increased. In addition, BP and RSNA of rats with circadian disruption exhibited a greater decrease in the effects of microinjection of tempol, a superoxide scavenger, into the RVLM, compared to artificial cerebrospinal fluid (aCSF). Further investigation of the molecular mechanism by Western blotting showed that nuclear factor-erythroid-2-related factor 2 (Nrf2)/heme oxygenase 1 (HO1)/NAD(P)H: quinone oxidoreductase 1 (NQO1) signaling was down-regulated in the RVLM of circadian disruption rats. These data suggest that oxidative stress in the RVLM mediates sympathetic hyperactivity induced by circadian disruption and possibly by down-regulating Nrf2/HO1/NQO1 signaling.

The interleukin-enhanced binding factor 3-mediated inhibition of nitric oxide production via phosphoinositide 3-kinase/protein kinase B pathway contributes to central cardiovascular regulation in the rostral ventrolateral medulla in hypertension.

Hypertension is characterized by sympathetic hyperactivity, which is related to the overexcitation of the presympathetic neurons in the rostral ventrolateral medulla (RVLM). Nitric oxide (NO) has been reported to be a vital neuromodulator involved in central cardiovascular regulation. However, the mechanism of interleukin-enhanced binding factor 3 (ILF3) participating in blood pressure (BP) regulation is still unclear. Therefore, this study aims to clarify the role of ILF3 within the rostral ventrolateral medulla (RVLM) in regulating NO in hypertension. It was found that the expression level of ILF3 was significantly increased in the RVLM of spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto (WKY) rats through microarray gene expression analysis, Western blot, and immunofluorescence. Overexpression of ILF3 by injecting constructed adenovirus into the RVLM increased the BP and renal sympathetic nerve activity (RSNA) of the WKY rats, significantly decreasing NO production and neuronal nitric oxide synthase (nNOS) expression. Knockdown of ILF3 in the RVLM of SHR significantly reduced BP but increased NO production and the neuronal nitric oxide synthase (nNOS) expression. Furthermore, it was found that the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway was activated via Western blotting in the RVLM after overexpression of ILF3, whereas it was attenuated after knockdown of ILF3 in SHR. In addition, inhibition of PI3K by intracisternal infusion of the PI-103 attenuated the increase in Akt phosphorylation and decrease in nNOS expression and NO production caused by overexpressing ILF3, which ultimately blunted high BP induced by overexpressing ILF3. Taken together, this current study suggests that ILF3 participates in high BP via reducing NO production in the RVLM through PI3K/Akt pathway.

Lanostane triterpenoids from Ganoderma lucidum and their inhibitory effects against FAAH.

Ganoderma lucidum is a famous edible and medicinal fungus. Through a bioactive phytochemical investigation of the ethanolic extracts of the fruiting bodies of G. lucidum, twenty-nine triterpenoids, including eleven previously undescribed triterpenoids, were isolated and characterized based on spectroscopic data. The inhibitory effects of all the triterpenes against fatty acid amide hydrolase (FAAH) were found to be in the range of 30-60% at 100 µM. Methyl ganoderate A displayed the strongest inhibitory activity (61%) against FAAH. Furthermore, all compounds displayed no cytotoxicity against LOVO and MCF-7 human cancer cells. Hence, our present study provides information about G. lucidum as a functional food or pharmaceutical supplement for the treatment of neuroinflammation.

ß-Arrestin1 Reduces Oxidative Stress via Nrf2 Activation in the Rostral Ventrolateral Medulla in Hypertension.

Oxidative stress in the rostral ventrolateral medulla (RVLM), a key region for blood pressure (BP) regulation, has been demonstrated to be responsible for the overactivity of the sympathetic nervous system in hypertension and heart failure. Nuclear factor-erythroid-2-related factor 2 (Nrf2) is a key transcription factor that maintains redox homeostasis by governing a broad array of antioxidant genes in response to oxidative stress. ß-Arrestin1 is a multifunctional scaffold protein with the ability to interact with diverse signaling molecules independent of G protein-coupled receptors (GPCRs), and its overexpression in the RVLM could reduce BP and renal sympathetic nerve activity (RSNA) in spontaneously hypertensive rats (SHR). The goal of this study was to investigate whether Nrf2-mediated antioxidative stress is involved in the antihypertensive effect of ß-arrestin1 in the RVLM. It was found that the activation level of Nrf2 in the RVLM of SHR was significantly reduced, compared with normotensive Wistar-Kyoko (WKY) rats. Overexpression of ß-arrestin1 in the RVLM significantly decreased ROS production and facilitated the Nrf2 activation in the RVLM of SHR, accompanied by upregulating the expression of HO-1 and NQO-1. However, Nrf2 knockdown attenuated the antioxidant effect of ß-arrestin1 overexpression in the RVLM by downregulating HO-1 and NQO-1 expression levels. In conclusion, the current results suggested that the antihypertensive effect of ß-arrestin1 overexpression in the RVLM is mediated by decreased ROS production, which is associated with Nrf2 activation.