Mobilization of regulatory T cells in response to carotid injury does not influence subsequent neointima formation

Innate and Adaptive Immune Cells Associates with Arteriovenous Fistula Maturation and Failure

Creation of arteriovenous fistula (AVF) causes local injury resulting in immune response of the body and infiltration of immune cells. Acute inflammation is favorable to control inflammation and proceed AVF towards maturation while chronic inflammation in AVF lead to AVF maturation failure. Chronic inflammation in AVF is due to chronic infiltration of immune cells and secretion of inflammatory cytokines. A balance between pro-inflammatory and anti-inflammatory response is must for AVF maturation and an overwhelmed proinflammatory infiltrate endue chronic inflammation and AVF failure. Since immune cell infiltration plays a critical role in maturation and failure of AVF, it is important to investigate the role of immune cells as well as their density in early and late phase of AVF maturation. The role of inflammation has been discussed in the literature and this review article focuses on the role of pro- and anti-inflammatory immune cells including macrophages, dendritic cells, T-cells, and T-regulatory cells in AVF maturation and maturation failure.

The p53 pathway in vasculature revisited: A therapeutic target for pathological vascular remodeling?

Pathological vascular remodeling contributes to the development of restenosis following intraluminal interventions, transplant vasculopathy, and pulmonary arterial hypertension. Activation of the tumor suppressor p53 may counteract vascular remodeling by inhibiting aberrant proliferation of vascular smooth muscle cells and repressing vascular inflammation. In particular, the development of different lines of small-molecule p53 activators ignites the hope of treating remodeling-associated vascular diseases by targeting p53 pharmacologically. In this review, we discuss the relationships between p53 and pathological vascular remodeling, and summarize current experimental data suggesting that drugging the p53 pathway may represent a novel strategy to prevent the development of vascular remodeling.

Healing the Broken Heart; The Immunomodulatory Effects of Stem Cell Therapy

Cardiovascular Disease (CVD) is a leading cause of mortality within the United States. Current treatments being administered to patients who suffered a myocardial infarction (MI) have increased patient survival, but do not facilitate the replacement of damaged myocardium. Recent studies demonstrate that stem cell-based therapies promote myocardial repair; however, the poor engraftment of the transferred stem cell populations within the infarcted myocardium is a major limitation, regardless of the cell type. One explanation for poor cell retention is attributed to the harsh inflammatory response mounted following MI. The inflammatory response coupled to cardiac repair processes is divided into two distinct phases. The first phase is initiated during ischemic injury when necrosed myocardium releases Danger Associated Molecular Patterns (DAMPs) and chemokines/cytokines to induce the activation and recruitment of neutrophils and pro-inflammatory M1 macrophages (MΦs); in turn, facilitating necrotic tissue clearance. During the second phase, a shift from the M1 inflammatory functional phenotype to the M2 anti-inflammatory and pro-reparative functional phenotype, permits the resolution of inflammation and the establishment of tissue repair. T-regulatory cells (Tregs) are also influential in mediating the establishment of the pro-reparative phase by directly regulating M1 to M2 MΦ differentiation. Current studies suggest CD4+ T-lymphocyte populations become activated when presented with autoantigens released from the injured myocardium. The identity of the cardiac autoantigens or paracrine signaling molecules released from the ischemic tissue that directly mediate the phenotypic plasticity of T-lymphocyte populations in the post-MI heart are just beginning to be elucidated. Stem cells are enriched centers that contain a diverse paracrine secretome that can directly regulate responses within neighboring cell populations. Previous studies identify that stem cell mediated paracrine signaling can influence the phenotype and function of immune cell populations in vitro, but how stem cells directly mediate the inflammatory microenvironment of the ischemic heart is poorly characterized and is a topic of extensive investigation. In this review, we summarize the complex literature that details the inflammatory microenvironment of the ischemic heart and provide novel insights regarding how paracrine mediated signaling produced by stem cell-based therapies can regulate immune cell subsets to facilitate pro-reparative myocardial wound healing.

Identification of type IV collagen exposure as a molecular imaging target for early detection of thoracic aortic dissection

Thoracic aortic dissection (TAD) is an aggressive and life-threatening vascular disease and there is no effective means of early diagnosis of dissection. Type IV collagen (Col-IV) is a major component of the sub-endothelial basement membrane, which is initially exposed followed by endothelial injury as early-stage event of TAD. So, we want to build a noninvasive diagnostic method to detect early dissection by identifying the exposed Col-IV via MRI.

METHODS

Col-IV-targeted magnetic resonance/ fluorescence dual probe (Col-IV-DOTA-Gd-rhodamine B; CDR) was synthesized by amide reaction and coordination reaction. Flow cytometry analysis was used to evaluate the cell viability of SMC treated with CDR and fluorescence assays were used to assess the Col-IV targeting ability of CDR in vitro. We then examined the sensitivity and specificity of CDR at different stages of TAD via MRI and bioluminescence imaging in vivo.

RESULTS

The localization of Col-IV (under the intima) was observed by histology images. CDR bound specifically to Col-IV-expressing vascular smooth muscle cells and BAPN-induced dissected aorta. The CDR signal was co-detected by magnetic resonance imaging (MRI) and bioluminescence imaging as early as 2 weeks after BAPN administration (pre-dissection stage). The ability to detect rupture of dissected aorta was indicated by a strong normalized signal enhancement (NSE) in vivo. Moreover, NSE was negatively correlated with the time of dissection rupture after BAPN administration (r2 = 0.8482).

CONCLUSION

As confirmed by in vivo studies, the CDR can identify the exposed Col-IV in degenerated aorta to monitor the progress of aortic dissection from the early stage to the rupture via MRI. Thus, CDR-enhanced MRI proposes a potential method for dissection screening, and for monitoring disease progression and therapeutic response.

Cortistatin reduces atherosclerosis in hyperlipidemic ApoE-deficient mice and the formation of foam cells

Atherosclerosis is a chronic inflammatory cardiovascular disease that is responsible of high mortality worldwide. Evidence indicates that maladaptive autoimmune responses in the arterial wall play critical roles in the process of atherosclerosis. Cortistatin is a neuropeptide expressed in the vascular system and atherosclerotic plaques that regulates vascular calcification and neointimal formation, and inhibits inflammation in different experimental models of autoimmune diseases. Its role in inflammatory cardiovascular disorders is largely unexplored. The aim of this study is to investigate the potential therapeutic effects of cortistatin in two well-established preclinical models of atherosclerosis, and the molecular and cellular mechanisms involved. Systemic treatment with cortistatin reduced the number and size of atherosclerotic plaques in carotid artery, heart, aortic arch and aorta in acute and chronic atherosclerosis induced in apolipoprotein E-deficient mice fed a high-lipid diet. This effect was exerted at multiple levels. Cortistatin reduced Th1/Th17-driven inflammatory responses and increased regulatory T cells in atherosclerotic arteries and lymphoid organs. Moreover, cortistatin reduced the capacity of endothelial cells to bind and recruit immune cells to the plaque and impaired the formation of foam cells by enhancing cholesterol efflux from macrophages. Cortistatin emerges as a new candidate for the treatment of the clinical manifestations of atherosclerosis.

Knockout of CD8 delays reendothelialization and accelerates neointima formation in injured arteries of mouse via TNF-α inhibiting the endothelial cells migration

Objective

Delayed or impaired reendothelialization is a major cause of stent thrombosis in the interventional treatment of coronary heart disease. T cells are involved in neointima formation of injured arteries. However, the regulated mechanism of reendothelialization and the role of CD8 T cell in reendothelialization are unclear.

Methods and Results

Immunofluorescence staining showed that CD8 positive cells were increased in wire injured femoral artery of mice. On day 21 after injury, elastin staining showed that knockout of CD8 (CD8^−/−) significantly increased intimal thickness and a ratio of intima to media by 1.8 folds and 1.9 folds respectively in injured arteries. Evans blue staining showed that knockout of CD8 delayed the reendothelialization area on day 7 after injury (18.8±0.5% versus 42.1±5.6%, p<0.05). In vitro, a migration assay revealed that CD8^−/− T cells co-cultured with WT macrophages significantly inhibited the migration of the endothelial cells (ECs); compared to CD4⁺ T cells, and CD8⁺ T cells could promote the ECs migration. Furthermore, real-time PCR analysis showed that knockout of CD8 increased the level of tumor necrosis factor α (TNF-α) in injured arteries and cytometric bead cytokine array showed that TNF-α was elevated in cultured CD8^−/− T cells. Finally, a wound-healing assay showed that recombinant TNF-α significantly inhibited the migration of ECs.

Conclusion

Our study suggested that CD8⁺ T cells could promote the reendothelialization and inhibit the neointima formation after the artery wire injury, and this effect is at least partly dependent on decreasing TNF-α production promoting ECs migration.