Ada Francesca Giglio

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.

Increased risk of myocardial infarction with dabigatran: fact or fiction?

Dabigatran is a direct, competitive inhibitor of thrombin recently approved for the prophylaxis of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. In some of the clinical trials evaluating the efficacy and safety of dabigatran in different clinical settings [i.e., prevention of venous thromboembolism (VTE) after orthopedic surgery, secondary prevention of VTE, and acute coronary syndromes (ACS)], a trend toward an increase in acute coronary events among patients receiving dabigatran has been reported, thus raising concerns of a possible relationship between dabigatran and myocardial infarction, especially in high-risk patients. However, as shown in our article, current evidence is inconclusive on this topic; more data are needed to detail this hypothetical association, and other considerations, such as the well-known protective effect of warfarin against ACS, should be taken into account as a possible explanation.

Human epicardium-derived cells fuse with high efficiency with skeletal myotubes and differentiate toward the skeletal muscle phenotype: a comparison study with stromal and endothelial cells

EPDCs fuse with skeletal myotubes with higher efficiency when compared to MSCs and endothelial cells. Independently from the cell origin, all nuclei recruited inside myotubes express muscle-specific genes. VCAM1 expression in nonmuscle cells is induced by soluble factors secreted by myotubes, and its function is required for fusion to occur.

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.

Inflammatory markers in heart failure: hype or hope?

Heart failure is a growing global epidemic that involves in its pathophysiology a proinflammatory state. Since the first description of elevated cytokine levels in this setting, there has been increasing interest in understanding the role of these molecules in left-ventricular remodeling and function. Over the years, intense research on the ‘cytokine theory’ of heart failure has allowed evaluation of the role of inflammatory biomarkers not only as pathogenetic mediators, but also as potential tools in the diagnosis and risk stratification of heart failure patients. Whereas current evidence does not support the use of inflammatory biomarkers for the diagnosis of heart failure, the assessment of their levels and the connection between their changes and changes in clinical status and prognosis has been well validated. At present, the utility of anti-inflammatory therapies in heart failure is still debated, since trials of anti-inflammatory agents in this setting have pointed out controversial results. On the contrary, established treatments of heart failure, including &bgr;-blockers, renin–angiotensin system antagonists, and aldosterone-receptor blockers seem able to act by modulating cytokine expression, suggesting a new role for these molecules in guiding heart failure therapy. Therefore, the binomial topic of heart failure and inflammation still has a number of fields not completely explored: our aim is to update current knowledge and future perspectives.

Epicardial adipose tissue microbial colonization and inflammasome activation in acute coronary syndrome

BACKGROUND Epicardial adipose tissue (EAT) has a close functional and anatomic relationship with epicardial coronary arteries. Accumulating evidence suggests that host microbiome alterations may play a role in several inflammatory/immune disorders, triggering a robust proinflammatory response also involving interleukin-1β (IL-1β) and the NALP3 inflammasome. In the current study, we explore the hypothesis that in patients with non-ST elevation acute coronary syndrome (ACS), EAT contains potentially pro-atherosclerotic bacteria that might elicit inflammasome activation. METHODS EAT samples were obtained during coronary artery bypass grafting from ACS (n=18) and effort stable angina (SA; n=16) patients, and as controls, from patients with angiographically normal coronary arteries undergoing surgery for mitral insufficiency (MVD; n=13). In all patients, NALP3 and proIL-1β mRNA expressions were evaluated with qRT-PCR. In 3 patients from each group, EAT microbiota composition was determined using next-generation sequencing technologies. RESULTS In EAT, mRNA expression of both NALP3 and pro-IL1β was significantly higher in ACS than in SA and MVD (P=0.028 and P=0.005, respectively). A broad range of bacterial species (n=76) was identified in both ACS and SA, with different predominant species. In contrast, microbial DNA was barely observed in MVD. CONCLUSIONS Our study demonstrated the presence of bacterial DNA directly into EAT, surrounding diseased coronary arteries, of patients with ACS. Furthermore, ACS is associated with NALP3/inflammasome pathway activation in EAT. Our data suggest that the EAT environment is susceptible to microbial colonization that might stimulate a proinflammatory response. These findings add new elements to the pathogenesis of ACS and suggest novel therapeutic targets.

Type 2 Diabetes, Immunity and Cardiovascular Risk: A Complex Relationship

Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes is associated with long-term damage, dysfunction, and failure of various organs, especially the eyes, kidneys, nerves, heart, and blood vessels (Expert Committee on the Diagnosis and Classification of Diabetes Mellitus, 1997, 2003)

Inflammasome, T Lymphocytes and Innate-Adaptive Immunity Crosstalk: Role in Cardiovascular Disease and Therapeutic Perspectives

Over the past few decades, lot of evidences have shown atherosclerosis as a chronic progressive disease with an exquisite inflammatory feature. More recently, the role of innate immune response in the onset and progression of coronary artery disease (CAD) and an adaptive immunity imbalance, mostly involving T cell sub-sets, have been documented. Therefore, like in many other inflammatory and autoimmune disorders, an altered innate-adaptive immunity crosstalk could represent the key of the inflammatory burden leading to atherosclerotic plaque formation and progression and to the breakdown of plaque stability. In this review, we will address the role of inflammasome in innate immunity and in the imbalance of adaptive immunity. We will discuss how this altered immune crosstalk is related to CAD onset and progression. We will also discuss how unravelling the key molecular mechanisms is of paramount importance in the development of therapeutic tools to delay the chronic progression and prevent the acute destabilization of atherosclerotic plaque.

Atorvastatin inhibits the immediate-early response gene EGR1 and improves the functional profile of CD4+T-lymphocytes in acute coronary syndromes

Background- Adaptive immune-response is associated with a worse outcome in acute coronary syndromes. Statins have anti-inflammatory activity beyond lowering lipid levels. We investigated the effects of ex-vivo and in-vivo atorvastatin treatment in acute coronary syndromes on CD4+T-cells, and the underlying molecular mechanisms. Approach and results- Blood samples were collected from 50 statin-naïve acute coronary syndrome patients. We assessed CD4+T-cell activation by flow-cytometry, the expression of 84 T-helper transcription-factors and 84 T-cell related genes by RT-qPCR, and protein expression by Western-blot, before and after 24-hours incubation with increasing doses of atorvastatin: 3-10-26 g/ml (corresponding to blood levels achieved with doses of 10-40-80 mg, respectively). After incubation, we found a significant decrease in interferon-?-producing CD4+CD28nullT-cells (P = 0.009) and a significant increase in interleukin-10-producing CD4+CD25highT-cells (P < 0.001). Atorvastatin increased the expression of 2 genes and decreased the expression of 12 genes (in particular, EGR1, FOS,CCR2 and toll like receptor-4; >3-fold changes). The in-vivo effects of atorvastatin were analyzed in 10 statin-free acute coronary syndrome patients at baseline, and after 24h and 48h of atorvastatin therapy (80 mg/daily): EGR1-gene expression decreased at 24h (P = 0.01) and 48h (P = 0.005); EGR1-protein levels decreased at 48h (P = 0.03). Conclusions-In acute coronary syndromes, the effects of atorvastatin on immune system might be partially related to the inhibition of the master regulator gene EGR1. Our finding might offer a causal explanation on why statins improve the early outcome in acute coronary syndromes.

MATRIX METALLOPROTEINASE 9 DRIVES THE SHEDDING OF CD31 IN ACUTE CORONARY SYNDROMES

Background: T-cells in acute coronary syndromes (ACS) show reduced expression and activity of the immunomodulatory molecule CD31 compared to patients with stable angina (SA). In T-cells, the shedding of the CD31 functional domains 1 to 5 leads to uncontrolled lymphocyte activation. A recent