Regulatory T cells and cardiovascular diseases

Macrophages in vascular disease: Roles of mitochondria and metabolic mechanisms

Macrophages are a dynamic cell type of the immune system implicated in the pathophysiology of vascular diseases and are a major contributor to pathological inflammation. Excessive macrophage accumulation, activation, and polarization is observed in aortic aneurysm (AA), atherosclerosis, and pulmonary arterial hypertension. In general, macrophages become activated and polarized to a pro-inflammatory phenotype, which dramatically changes cell behavior to become pro-inflammatory and infiltrative. These cell types become cumbersome and fail to be cleared by normal mechanisms such as autophagy. The result is a hyper-inflammatory environment causing the recruitment of adjacent cells and circulating immune cells to further augment the inflammatory response. In AA, this leads to excessive ECM degradation and chemokine secretion, ultimately causing macrophages to dominate the immune cell landscape in the aortic wall. In atherosclerosis, monocytes are recruited to the vascular wall, where they polarize to the pro-inflammatory phenotype and induce inflammatory pathway activation. This leads to the development of foam cells, which significantly contribute to neointima and necrotic core formation in atherosclerotic plaques. Pro-inflammatory macrophages, which affect other vascular diseases, present with fragmented mitochondria and corresponding metabolic dysfunction. Targeting macrophage mitochondrial dynamics has proved to be an exciting potential therapeutic approach to combat vascular disease. This review will summarize mitochondrial and metabolic mechanisms of macrophage activation, polarization, and accumulation in vascular diseases.

Effects and mechanisms of the myocardial microenvironment on cardiomyocyte proliferation and regeneration

The adult mammalian cardiomyocyte has a limited capacity for self-renewal, which leads to the irreversible heart dysfunction and poses a significant threat to myocardial infarction patients. In the past decades, research efforts have been predominantly concentrated on the cardiomyocyte proliferation and heart regeneration. However, the heart is a complex organ that comprises not only cardiomyocytes but also numerous noncardiomyocyte cells, all playing integral roles in maintaining cardiac function. In addition, cardiomyocytes are exposed to a dynamically changing physical environment that includes oxygen saturation and mechanical forces. Recently, a growing number of studies on myocardial microenvironment in cardiomyocyte proliferation and heart regeneration is ongoing. In this review, we provide an overview of recent advances in myocardial microenvironment, which plays an important role in cardiomyocyte proliferation and heart regeneration.

Therapeutic potential of natural products and underlying targets for the treatment of aortic aneurysm

Aortic aneurysm is a vascular disease characterized by irreversible vasodilatation that can lead to dissection and rupture of the aortic aneurysm, a life-threatening condition. Thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA) are two main types. The typical treatments for aortic aneurysms are open surgery and endovascular aortic repair, which are only indicated for more severe patients. Most patients with aneurysms have an insidious onset and slow progression, and there are no effective drugs to treat this stage. The inability of current animal models to perfectly simulate all the pathophysiological states of human aneurysms may be the key to this issue. Therefore, elucidating the molecular mechanisms of this disease, finding new therapeutic targets, and developing effective drugs to inhibit the development of aneurysms are the main issues of current research. Natural products have been applied for thousands of years to treat cardiovascular disease (CVD) in China and other Asian countries. In recent years, natural products have combined multi-omics, computational biology, and integrated pharmacology to accurately analyze drug components and targets. Therefore, the multi-component and multi-target complexity of natural products have made them a potentially ideal treatment for multifactorial diseases such as aortic aneurysms. Natural products have regained popularity worldwide. This review provides an overview of the known natural products for the treatment of TAA and AAA and searches for potential cardiovascular-targeted natural products that may treat TAA and AAA based on various cellular molecular mechanisms associated with aneurysm development.

Longitudinal Variations in Th and Treg Cells Before and After Percutaneous Coronary Intervention, and Their Intercorrelations and Prognostic Value in Acute Syndrome Patients

T helper (Th) and regulatory T (Treg) cells regulate atherosclerosis, plaque, inflammation to involve in acute coronary syndrome (ACS). The current study aimed to investigate the clinical implications of Th and Treg cells in ACS patients receiving percutaneous coronary intervention (PCI). Blood Th1, Th2, Th17 and Treg cells were detected in 160 ACS patients before PCI, after PCI, at 1 month (M). Short physical performance battery (SPPB) at M1/M3 and major adverse cardiac event (MACE) during follow-ups were evaluated. Th1 and Th17 both showed upward trends during PCI, then greatly declined at M1 (P < 0.001). Th2 exhibited an upward trend during PCI but decreased slightly at M1 (P < 0.001). Treg remained stable during PCI but elevated at M1 (P < 0.001). Moreover, a positive correlation between Th1 and Th17, a negative correlation between Th17 and Treg, were discovered at several timepoints (most P < 0.050). Interestingly, the receiver operating curve (ROC) analyses revealed that Th1 [area under curve (AUC) between 0.633-0.645] and Th17 (AUC between 0.626-0.699) exhibited values estimating SPPB score <= 6 points at M1 or M3 to some extent. Importantly, Th1 (AUC between 0.708-0.710), Th17 (AUC between 0.694-0.783), and Treg (AUC between 0.706-0.729) predicted MACE risk. Multivariate models involving Th and Treg cells along with other characteristics revealed acceptable values estimating SPPB score <= 6 points at M1 or M3 (AUC between 0.690-0.813), and good values predicting MACE risk (AUC between 0.830-0.971). Dynamic variations in Th and Treg cells can predict the prognosis of ACS patients receiving PCI.

Trained Innate Immunity in Animal Models of Cardiovascular Diseases

Acquisition of immunological memory is an important evolutionary strategy that evolved to protect the host from repetitive challenges from infectious agents. It was believed for a long time that memory formation exclusively occurs in the adaptive part of the immune system with the formation of highly specific memory T cells and B cells. In the past 10-15 years, it has become clear that innate immune cells, such as monocytes, natural killer cells, or neutrophil granulocytes, also have the ability to generate some kind of memory. After the exposure of innate immune cells to certain stimuli, these cells develop an enhanced secondary response with increased cytokine secretion even after an encounter with an unrelated stimulus. This phenomenon has been termed trained innate immunity (TI) and is associated with epigenetic modifications (histone methylation, acetylation) and metabolic alterations (elevated glycolysis, lactate production). TI has been observed in tissue-resident or circulating immune cells but also in bone marrow progenitors. Risk-factors for cardiovascular diseases (CVDs) which are associated with low-grade inflammation, such as hyperglycemia, obesity, or high salt, can also induce TI with a profound impact on the development and progression of CVDs. In this review, we briefly describe basic mechanisms of TI and summarize animal studies which specifically focus on TI in the context of CVDs.