An important prognostic factor in any form of infection seems to be glucose control in patients with type 2 diabetes. There is no information about the effects of tight glycemic control on coronavirus disease 2019 (COVID-19) outcomes in patients with hyperglycemia. Therefore, we examined the effects of optimal glycemic control in patients with hyperglycemia affected by COVID-19. RESEARCH DESIGN AND METHODS Fifty-nine patients with COVID-19 hospitalized with moderate disease were evaluated. On the basis of admission glycemia >7.77 mmol/L, patients were divided into hyperglycemic and normoglycemic groups. Interleukin 6 (IL-6) and D-dimer levels were evaluated at admission and weekly during hospitalization. The composite end point was severe disease, admission to an intensive care unit, use of mechanical ventilation, or death. RESULTS Thirty-four (57.6%) patients were normoglycemic and 25 (42.4%) were hyperglycemic. In the hyperglycemic group, 7 (28%) and 18 (72%) patients were diagnosed with diabetes already before admission, and 10 (40%) and 15 (60%) were treated without and with insulin infusion, respectively. The mean of glycemia during hospitalization was 10.65 6 0.84 mmol/L in the no insulin infusion group and 7.69 6 1.85 mmol/L in the insulin infusion group. At baseline, IL-6 and D-dimer levels were significantly higher in the hyperglycemic group than in the normoglycemic group (P < 0.001). Even though all patients were on standard treatment for COVID-19 infection, IL-6 and D-dimer levels persisted higher in patients with hyperglycemia during hospitalization. In a risk-adjusted Cox regression analysis, both patients with hyperglycemia and patients with diabetes had a higher risk of severe disease than those without diabetes and with normoglycemia. Cox regression analysis evidenced that patients with hyperglycemia treated with insulin infusion had a lower risk of severe disease than patients without insulin infusion. CONCLUSIONS Insulin infusion may be an effective method for achieving glycemic targets and improving outcomes in patients with COVID-19.

Significance: Oxidative stress represents the common hallmark of pathological conditions associated with cardiovascular disease (CVD), including atherosclerosis, heart failure, hypertension, aging, diabetes, and other vascular system-related diseases. The sirtuin (SIRT) family, comprising seven proteins (SIRT1-SIRT7) sharing a highly conserved nicotinamide adenine dinucleotide (NAD + )-binding catalytic domain, attracted a great attention for the past few years as stress adaptor and epigenetic enzymes involved in the cellular events controlling aging-related disorder, cancer, and CVD. Recent Advances: Among sirtuins, SIRT1 and SIRT6 are the best characterized for their protective roles against inflammation, vascular aging, heart disease, and atherosclerotic plaque development. This latest role has been only recently unveiled for SIRT6. Of interest, in recent years, complex signaling networks controlled by SIRT1 and SIRT6 common to stress resistance, vascular aging, and CVD have emerged. Critical Issues: We provide a comprehensive overview of recent developments on the molecular signaling pathways controlled by SIRT1 and SIRT6, two post-translational modifiers proven to be valuable tools to dampen inflammation and oxidative stress at the cardiovascular level. Future Directions: A deeper understanding of the epigenetic mechanisms through which SIRT1 and SIRT6 act in the signalings responsible for onset and development CVD is a prime scientific endeavor of the upcoming years. Multiple ''omic'' technologies will have widespread implications in understanding such mechanisms, speeding up the achievement of selective and efficient pharmacological modulation of sirtuins for future applications in the prevention and treatment of CVD. Antioxid. Redox Signal. 28, 711-732.

The role of sirtuin 6 (SIRT6) in atherosclerotic progression of diabetic patients is unknown. We evaluated SIRT6 expression and the effect of incretin-based therapies in carotid plaques of asymptomatic diabetic and nondiabetic patients. Plaques were obtained from 52 type 2 diabetic and 30 nondiabetic patients undergoing carotid endarterectomy. Twenty-two diabetic patients were treated with drugs that work on the incretin system, GLP-1 receptor agonists, and dipeptidyl peptidase-4 inhibitors for 26 6 8 months before undergoing the endarterectomy. Compared with nondiabetic plaques, diabetic plaques had more inflammation and oxidative stress, along with a lesser SIRT6 expression and collagen content. Compared with non-GLP-1 therapy-treated plaques, GLP-1 therapy-treated plaques presented greater SIRT6 expression and collagen content, and less inflammation and oxidative stress, indicating a more stable plaque phenotype. These results were supported by in vitro observations on endothelial progenitor cells (EPCs) and endothelial cells (ECs). Indeed, both EPCs and ECs treated with high glucose (25 mmol/L) in the presence of GLP-1 (100 nmol/L liraglutide) presented a greater SIRT6 and lower nuclear factor-kB expression compared with cells treated only with high glucose. These findings establish the involvement of SIRT6 in the inflammatory pathways of diabetic atherosclerotic lesions and suggest its possible positive modulation by incretin, the effect of which is associated with morphological and compositional characteristics of a potential stable plaque phenotype.Cardiovascular disease represents the leading cause of death in patients with type 2 diabetes (1). Diabetes leads to increased vulnerability for plaque disruption, and mediates increased incidence and severity of clinical events (2). Inflammation, particularly in diabetes, plays a central role in the cascade of events that result in plaque erosion and fissuring (2). There is now increasing evidence that a number of transcription factors, including the Sir2 family of enzymes, namely sirtuins (SIRTs), regulate multiple genes whose products are putatively involved in the regulation of inflammation and endothelial cell (EC) function (3). The Sir2 family consists of seven enzymes (SIRT1 to SIRT7) that share a conserved core catalytic domain, but differ in their cellular localization and tissue distribution (4). Among the SIRTs, SIRT6, a chromatinassociated deacetylase, is considered to have a leading role in regulating genomic stability, cellular metabolism, stress response, and aging (5-8). A recent study (9) in mice suggested a role for SIRT6 in inflammation. Moreover, the knockdown of SIRT6 resulted in the increased expression of proinflammatory cytokines (interleukin [IL]-1b, IL-6, and IL-8), extracellular matrix remodeling enzymes (matrix metalloproteinase [MMP]-2, MMP-9, and plasminogen activator inhibitor 1), and intracellular adhesion molecule-1 (4). In ECs, the loss of SIRT6 was associated with an increased expression of nuclear factor-kB (NF-kB), whereas o...

To evaluate the effect of metformin therapy on coronary endothelial function and major adverse cardiac events (MACE) in patients with prediabetes with stable angina and nonobstructive coronary stenosis (NOCS). RESEARCH DESIGN AND METHODS Metformin therapy may be needed to reduce coronary heart disease risk in patients with prediabetes. A total of 258 propensity score-matched (PSM) patients with stable angina undergoing coronary angiography were enrolled in the study. Data from 86 PSM subjects with normoglycemia (NG), 86 PSM subjects with prediabetes (pre-DM), and 86 PSM subjects with prediabetes treated with metformin (pre-DM metformin) were analyzed. During coronary angiography, NOCS was categorized by luminal stenosis <40% and fractional flow reserve >0.80. In addition, we assessed the endothelial function, measuring coronary artery diameter of left anterior descending coronary (LAD) at baseline and after the infusion of acetylcholine, by means of an intracoronary Doppler guide wire. MACE, as cardiac death, myocardial infarction, and heart failure, was evaluated at 24 months of follow-up. RESULTS At baseline, NG patients had a lower percentage of LAD endothelial dysfunction compared with pre-DM patients (P < 0.05). The pre-DM patients had a higher percentage of endothelial LAD dysfunction as compared with the pre-DM metformin patients (P < 0.05). At the 24th month of follow-up, MACE was higher in pre-DM versus NG (P < 0.05). In pre-DM metformin patients, MACE was lower compared with pre-DM patients (P < 0.05). CONCLUSIONS Metformin therapy may reduce the high risk of cardiovascular events in pre-DM patients by reducing coronary endothelial dysfunction.