Daniela Pedicino

Expansion of CD4+CD28null T-lymphocytes in diabetic patients: exploring new pathogenetic mechanisms of increased cardiovascular risk in diabetes mellitus

AIMSnDiabetes mellitus (DM) is associated with high incidence of first and recurrent cardiovascular events, especially acute coronary syndromes (ACSs); however, the mechanisms involved are still unknown. We sought to investigate the role of CD4(+)CD28(null)T-lymphocytes, a rare long-lived subset of T-lymphocytes with proatherogenic and plaque-destabilizing properties, in the increased cardiovascular risk associated with DM.nnnMETHODS AND RESULTSnCD4(+)CD28(null)T-cell frequency was analysed by flow-cytometry in 60 DM patients without overt cardiovascular disease (cDM), in 166 ACS patients with or without DM (ACS/DM+, n= 51 and ACS/DM-, n= 115), and in 60 healthy individuals. The incidence of cardiovascular events (death, myocardial infarction, unstable angina) was assessed at 36 months follow-up. CD4+CD28(null)T-cell frequency (median, range) was higher in ACS/DM+ (12.7%, 0.1-48) vs. ACS/DM- (3.9%, 0.2-35), cDM (3.1%, 0.3-22.4), and controls (1.5%, 0.1-9.1) (P< 0.001 for all comparisons). Notably, cDM patients had significantly higher CD4+CD28(null)T-cell frequency than controls (P= 0.001). Glycosylated haemoglobin A(1c) was the only parameter independently associated with CD4+CD28(null)T-cells in cDM. The 36-month event-free survival was significantly lower in cDM patients with CD4+CD28(null)T-cells ≥4% (90th percentile of normal distribution) than in those with CD4+CD28(null)T-cells <4% (P= 0.039). Among ACS patients, the 36-month event-free survival was the lowest in those with DM and CD4+CD28(null)T-cells ≥4% and highest in those without DM and CD4+CD28(null)T-cells <4% (P< 0.001), being intermediate in those with only one of these features.nnnCONCLUSIONSnIn DM patients, CD4+CD28(null)T-cells are expanded and are associated with poor glycaemic control; they also correlate with the occurrence of a first cardiovascular event and with a worse outcome after an ACS.

Combined atherogenic effects of celiac disease and type 1 diabetes mellitus

OBJECTIVEnPrevious studies have shown a high cardiovascular risk in patients with autoimmune diseases, such as type 1 diabetes mellitus (T1DM). Conversely, few data are available about patients with celiac disease (CD). The aim of our study was to assess carotid intima-media thickness (c-IMT), in patients with T1DM, CD or both (T1DM+CD) as compared with age- and sex-matched healthy individuals (H).nnnMETHODSnWe enrolled 120 patients, 30 with T1DM, 30 with CD, 30 with T1DM+CD and 30 H. Clinical, metabolic and anthropometric data were collected. All T1DM patients were on insulin while all CD patients were on a gluten-free diet. c-IMT was evaluated by high frequency linear digital ultrasound.nnnRESULTSnc-IMT was significantly greater in patients with T1DM+CD than in patients with T1DM or CD (P<0.001 for both), while no difference was found between T1DM and CD. Moreover, c-IMT was greater in CD than in H (P<0.001). Glycemic control and disease duration were similar between T1DM+CD and T1DM. Lipid and anthropometric parameters were similar among groups. Furthermore, in a pooled multivariate analysis, only age and disease type were significantly correlated with c-IMT (P<0.001 for both).nnnCONCLUSIONnOur study demonstrates that celiac patients have greater c-IMT as compared with healthy individuals. Thus, non-invasive monitoring of c-IMT in CD might be useful in preventing cardiovascular disease. Moreover, patients with T1DM+CD show more severe subclinical atherosclerosis as compared with those presenting T1DM or CD only, suggesting that the association of these autoimmune diseases might accelerate the atherosclerotic process.

Interleukin-17 in atherosclerosis and cardiovascular disease: the good, the bad, and the unknown

This editorial refers to ‘Circulating levels of interleukin-17 and cardiovascular outcomes in patients with acute myocardial infarction’, by T. Simon et al. , doi:10.1093/eurheartj/ehs263nnOver the past few years our understanding of the importance of adaptive immunity in acute coronary syndromes (ACS) has considerably increased.1 Profound abnormalities have been observed in specific subsets of CD4+T cells, including type 1 helper T (Th1) cells,2,3 CD4+CD28nullT cells,4 and naturally occurring regulatory T cells (Treg cells).5nnRecently a new lineage of CD4+T cells, type 17 helper T (Th17) cells producing the signature cytokines interleukin (IL)-17, IL-21, and IL-22, has been identified.6 This has fundamentally changed the Th1/Th2 dichotomy paradigm. The Th1 cell subset is characterized by interferon (IFN)-γ production and T-bet expression, whereas the Th2 cell lineage shows IL-4, IL-5, and IL-10 production and GATA-3 expression. At the other extreme, Treg cells expressing FoxP3 are essential to maintain the homeostasis of cell subsets involved in adaptive immunity by contact-dependent suppression or by releasing anti-inflammatory cytokines, IL-10 and transforming growth factor (TGF)-β1.7nnLike Th1, Th2, and Treg cells, specific polarizing cytokines—TGF-β, IL-6, and IL-23—are required for differentiation of Th17 cells which express the transcription factors retinoic acid orphan receptor (ROR) α and RORγt. However, Th17 cells do not represent a homogeneous lineage, as they can be reprogrammed to other T-cell subsets depending on the cytokine environment.6 Accordingly, IL-17 can be co-expressed with a variety of other cytokines including IFN-γ, IL-10, and IL-4. Indeed, a mixed Th1–Th17 subgroup expressing both T-bet and RORγt has been recently identified in the setting of autoimmunity.6 Plasticity …

Adaptive immunity, inflammation, and cardiovascular complications in type 1 and type 2 diabetes mellitus.

Diabetes mellitus (DM) is a pandemics that affects more than 170 million people worldwide, associated with increased mortality and morbidity due to coronary artery disease (CAD). In type 1 (T1) DM, the main pathogenic mechanism seems to be the destruction of pancreatic β-cells mediated by autoreactive T-cells resulting in chronic insulitis, while in type 2 (T2) DM primary insulin resistance, rather than defective insulin production due to β-cell destruction, seems to be the triggering alteration. In our study, we investigated the role of systemic inflammation and T-cell subsets in T1- and T2DM and the possible mechanisms underlying the increased cardiovascular risk associated with these diseases.

Infections, immunity and atherosclerosis: Pathogenic mechanisms and unsolved questions

The role of inflammation and immunity in the pathogenesis and clinical manifestations of atherosclerotic disease has been widely studied. Common infectious diseases can be associated with a chronic inflammatory state which is the hallmark of atherosclerosis, thus suggesting a possible link between the two pathological conditions. Therefore, a great number of studies have tested the infection hypothesis, but their results are conflicting. Nevertheless, several molecular and biological mechanisms possibly involved in the complex relationship between infections, immune response, vascular wall damage and atherosclerosis onset and progression have been described. The purpose of this article is to offer an overview of the principal mechanisms and molecular pathways that probably constitute the most relevant biological substrate on which the infection hypothesis is founded; some of these mechanisms are not fully understood yet. Nevertheless, their comprehension could be essential for the development of new preventive and therapeutic strategies.

Increased PTPN22 Expression and Defective CREB Activation Impair Regulatory T-Cell Differentiation in Non-ST-Segment Elevation Acute Coronary Syndromes

BACKGROUNDnCritical impairment of adaptive immune response has been observed in patients with acute coronary syndromes (ACS) with reduced expansion of regulatory T cells (Treg) and enhanced effector T-cell responsiveness, both associated with poorer outcomes.nnnOBJECTIVESnThis study investigated the mechanisms underlying T-cell dysregulation in ACS.nnnMETHODSnWe evaluated both early and downstream T-cell receptor activation pathways after exxa0vivo stimulation with anti-CD3 and anti-CD28 crosslink in CD4(+) T cells from 20 patients with non-ST-segment elevation myocardial infarction (NSTEMI), 20 with stable angina (SA), and 20 controls. We reassessed 10 NSTEMI and 10 SA patients after 1 year.nnnRESULTSnPhospho-flow analysis revealed reduced phosphorylation of the zeta-chain-associated protein kinase of 70xa0kDa at the inhibitory residue tyrosine 292, enhancing T-cell activation, in NSTEMI helper T cells versus SA and controls (each, pxa0< 0.001), resulting from increased expression of the protein tyrosine phosphatase, nonreceptor type, 22 (PTPN22) (pxa0< 0.001 for both comparisons), persisting at follow-up. We also observed reduced phosphorylation (pxa0<xa00.001 versus controls) and lower levels of binding to interleukins 2 and 10 core promoter regions of the transcription factor cyclic adenosine monophosphate response element-binding protein (CREB) in NSTEMI (pxa0< 0.05 vs. controls), which recovered at 1 year. Finally, in NSTEMI patients, helper T cells had a reduced ability in T-cell receptor-induced Treg generation (pxa0= 0.002 vs. SA; pxa0= 0.001 vs. controls), partially recovered at 1 year. Restoring CREB activity and silencing PTPN22 enhanced NSTEMI patients ability to generate Treg.nnnCONCLUSIONSnThe persistent overexpression of PTPN22 and the transient reduction of CREB activity, associated with impaired Treg differentiation, might play a role in ACS.

Altered CD31 expression and activity in helper T cells of acute coronary syndrome patients

In acute coronary syndrome (ACS), T cell abnormalities are associated to a worse outcome. Loss of inhibitory activity of CD31, an Ig-like adhesion molecule, on peripheral leukocytes has been found to enhance atherosclerosis in experimental models. In this study, we examined the expression of CD31 on T cells, and its role on TCR signaling in 35 patients with non-ST elevation ACS, in 35 patients with stable angina (SA), and in 35 controls. Furthermore, 10 ACS and 10 SA patients were re-analyzed at 1-year follow-up. Flow-cytometry analysis showed that in ACS patients, CD31 expression was reduced on total CD4+ and CD4+CD28null (Pxa0<xa00.001, ACS vs. SA), on naïve (Pxa0<xa00.001, ACS vs. SA) and on central-memory and effector-memory CD4+ T cells (Pxa0<xa00.05, ACS vs. SA and controls). The immunomodulatory effect of CD31 on TCR signaling of CD4+ and CD4+CD28null T cells, was lower in ACS than SA patients (Pxa0<xa00.05, for both comparisons). At 1-year follow-up, CD31 expression and function increased in ACS becoming similar to that found in SA. CD31 recruitment in the immunological synapse was lower in ACS than controls (Pxa0=xa00.012). Moreover, CD31 modulated MAPK signaling and reduced the expression of T bet and Rorγ-t, necessary for Th1 and Th17 differentiation. Finally, we studied TCR signaling in CD31+ naïve and primed T cell subsets observing a different pattern of protein phosphorylation. A CD31-mediated regulatory pathway is enhanced in SA and temporarily downregulated in ACS. As CD31 modulates both T cell activation, by increasing the threshold for TCR stimulation, and T cell differentiation, it might represent a novel molecular target to treat T cell abnormalities in ACS.

Cardiovascular risk in obesity: Different activation of inflammation and immune system between obese and morbidly obese subjects

BACKGROUNDnBoth inflammation and immunity are involved in the development and progression of atherosclerosis. Obesity is considered a major modifiable cardiovascular risk factor, however, the correlation between increasing degrees of obesity and cardiovascular risk is not clear yet. Aim of our study was to investigate how different degrees of obesity are associated with inflammation and immune system responses.nnnMETHODSnOne-hundred healthy individuals were divided into 3 groups according to body mass index (BMI): 22 overweight (OW), 26 obese (O) and 52 morbidly obese (MO). High-sensitivity C-Reactive Protein (hs-CRP, immunonephelometry), leptin (radio-immunoassay) and CD4+CD28nullT-lymphocytes (flow-cytometry), a particular subset of T-lymphocytes with pro-atherogenic and plaque-destabilizing properties, were assessed.nnnRESULTSnhs-CRP levels were significantly higher in O vs OW (p=0.036), in MO vs OW (p<0.001) and in MO vs O (p=0.012). Similarly, leptin levels were higher in O vs OW (p=0.02), in MO vs OW (p<0.001) and in MO vs O (p<0.001). CD4+CD28nullT-lymphocytes were higher in O vs OW (p<0.001), in O vs MO (p=0.03) and in MO vs OW (p=0.01). hs-CRP and leptin levels significantly correlated each other (r=0.39; p<0.001) and with waist circumference (r=0.52; p<0.001; r=0.64; p<0.001) and BMI (r=0.60; p<0.001; r=0.74; p<0.001).nnnCONCLUSIONSnOur study demonstrates that, notwithstanding higher levels of inflammation, MO are characterized by less detrimental immune activation, as shown by the reduced CD4+CD28nullT-cells expansion as compared to OW and O, which might translate in less immune vascular injury. These findings suggest that MO might represent a particular population, in which different pathophysiological mechanisms take part if compared with classic obesity.

Anti-inflammatory Treatment of Acute Coronary Syndromes

The past decade has seen a steady growth in the treatment options available for Acute Coronary Syndromes (ACS), as a consequence of our better understanding of ACS pathophysiology. Administration of fibrinolytics in ST-elevation myocardial infarction, and of potent antiplatelet and anticoagulant drugs in all ACS, has allowed us to considerably improve their outcome. Yet, the rate of adverse cardiac events at early follow-up ranges from 15% to 20%. Thus, to further improve the outcome of ACS or to prevent their occurrence, it is important to identify new therapeutic target. A number of experimental and clinical studies have highlighted the key role of inflammation in all phases of atherosclerosis, from fatty streaks to disrupted plaques and raised levels of inflammatory markers have been associated to a poor outcome despite optimal treatment, including myocardial revascularization. In this review, we will focus on inflammation as a possible new therapeutic target of ACS, discussing the anti-inflammatory treatments in four sections: 1) non specific anti-inflammatory drugs; 2) specific antagonists of key cytokines; 3) immunomodulatory therapies; 4) immunization as promising therapeutic modality against atherosclerosis.

Reversible atrial gap junction remodeling during hypoxia/reoxygenation and ischemia: a possible arrhythmogenic substrate for atrial fibrillation.

Alteration of cardiomyocyte gap-junctions and component connexins (Cx) has been suggested to contribute to the development of atrial fibrillation (AF), including postoperative AF. We tested different possible stimuli, such as hypoxia and ischemia, influencing Cx43 and Cx40 expression and distribution in cultured atrial cells (HL-1) and reversibility of these processes after reoxygenation. Western-blot analysis and immunostaining using anti-Cx43, anti-Cx40 and anti-zonula occludens polyclonal antibodies were performed. HL-1 cells exposed to hypoxia for 24 and 48 h showed a reduction of Cx43 protein levels by 75% and 90% respectively (p < 0.001). During reoxygenation following 24 h of hypoxia, Cx43 levels increased to reach the basal level within 48 h, while they remained at low level during reoxygenation following 48 h of hypoxia. Furthermore, atrial cardiomyocytes subjected to simulated ischemia (SI) were incubated in normoxic and hypoxic conditions for 3, 6, 9, 12 h. Atrial cardiomyocytes subjected to SI in addition to normoxia showed a progressive reduction of Cx43 levels beginning from 3 h. During SI and hypoxia, atrial Cx43 levels showed an initial decrease after 3 h with a subsequent rescue beginning from 6 h of exposure (p = 0.001). Hypoxia and ischemia per se downregulate Cx43 protein expression in atrial cardiomyocytes, but protein downregulation is reversible, depending on hypoxia duration and the association of the two triggers. These alterations characterize several conditions and might contribute to the generation of an arrhythmogenic substrate leading to AF onset and/or maintenance.