Effects of exenatide on cardiac function, perfusion, and energetics in type 2 diabetic patients with cardiomyopathy: a randomized controlled trial against insulin glargine.

BACKGROUND: Multiple bloodglucose-lowering agents have been linked to cardiovascular events. Preliminary studies showed improvement in left ventricular (LV) function during glucagon-like peptide-1 receptor agonist administration. Underlying mechanisms, however, are unclear. The purpose of this study was to investigate myocardial perfusion and oxidative metabolism in type 2 diabetic (T2DM) patients with LV systolic dysfunction as compared to healthy controls. Furthermore, effects of 26-weeks of exenatide versus insulin glargine administration on cardiac function, perfusion and oxidative metabolism in T2DM patients with LV dysfunction were explored. METHODS AND RESULTS: Twenty-six T2DM patients with LV systolic dysfunction (cardiac magnetic resonance (CMR) derived LV ejection fraction (LVEF) of 47 ± 13%) and 10 controls (LVEF of 59 ± 4%, P < 0.01 as compared to patients) were analyzed. Both myocardial perfusion during adenosine-induced hyperemia (P < 0.01), and coronary flow reserve (P < 0.01), measured by [15O]H2O positron emission tomography (PET), were impaired in T2DM patients as compared to healthy controls. Myocardial oxygen consumption and myocardial efficiency, measured using [11C]acetate PET and CMR derived stroke volume, were not different between the groups. Eleven patients in the exenatide group and 12 patients in the insulin glargine group completed the trial. Systemic metabolic control was improved after both treatments, although, no changes in cardiac function, perfusion and metabolism were seen after exenatide or insulin glargine. CONCLUSIONS: T2DM patients with LV systolic dysfunction did not have altered myocardial efficiency as compared to healthy controls. Exenatide or insulin glargine had no effects on cardiac function, perfusion or oxidative metabolism. Trial registration NCT00766857.

Systemic toll-like receptor and interleukin-18 pathway activation in patients with acute ST elevation myocardial infarction.

Acute myocardial infarction (AMI) is accompanied by increased expression of Toll like receptors (TLR)-2 and TLR4 on circulating monocytes. In animal models, blocking TLR2/4 signaling reduces inflammatory cell influx and infarct size. The clinical consequences of TLR activation during AMI in humans are unknown, including its role in long-term cardiac functional outcome Therefore, we analyzed gene expression in whole blood samples from 28 patients with an acute ST elevation myocardial infarction (STEMI), enrolled in the EXenatide trial for AMI patients (EXAMI), both at admission and after 4-month follow-up, by whole genome expression profiling and real-time PCR. Cardiac function was determined by cardiac magnetic resonance (CMR) imaging at baseline and after 4-month follow-up. TLR pathway activation was shown by increased expression of TLR4 and its downstream genes, including IL-18R1, IL-18R2, IL-8, MMP9, HIF1A, and NFKBIA. In contrast, expression of the classical TLR-induced genes, TNF, was reduced. Bioinformatics analysis and in vitro experiments explained this noncanonical TLR response by identification of a pivotal role for HIF-1α. The extent of TLR activation and IL-18R1/2 expression in circulating cells preceded massive troponin-T release and correlated with the CMR-measured ischemic area (R=0.48, p=0.01). In conclusion, we identified a novel HIF-1-dependent noncanonical TLR activation pathway in circulating leukocytes leading to enhanced IL-18R expression which correlated with the magnitude of the ischemic area. This knowledge may contribute to our mechanistic understanding of the involvement of the innate immune system during STEMI and may yield diagnostic and prognostic value for patients with myocardial infarction.

Activin A is associated with impaired myocardial glucose metabolism and left ventricular remodeling in patients with uncomplicated type 2 diabetes.

BACKGROUND: Activin A released from epicardial adipose tissue has been linked to contractile dysfunction and insulin resistance in cardiomyocytes. This study investigated the role of activin A in clinical diabetic cardiomyopathy by assessing whether circulating activin A levels associate with cardiometabolic parameters in men with uncomplicated type 2 diabetes (T2D), and the effects of treatment with pioglitazone versus metformin on these associations. METHODS: Seventy-eight men with uncomplicated T2D and fourteen healthy men with comparable age were included, in this randomized, double-blind, active comparator intervention study. All T2D men were on glimipiride monotherapy, and randomized to a 24-week intervention with either pioglitazone or metformin. Cardiac dimensions and -function were measured using magnetic resonance imaging, whilst myocardial glucose metabolism (MMRglu) was determined using [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography during a hyperinsulinemic-euglycemic clamp. RESULTS: Circulating activin A levels were comparable in T2D men and controls. Activin A levels were independently inversely associated with MMRglu, and positively with left ventricular mass/volume (LVMV)-ratio in T2D men. Intervention with metformin decreased activin A levels, whereas pioglitazone did not alter activin A levels. The changes in plasma activin A levels were not correlated with the changes in MMRglu following either pioglitazone or metformin treatment. A borderline significant correlation (p = 0.051) of changes in plasma activin A levels and changes in LVMV-ratio was observed after pioglitazone treatment. CONCLUSIONS: Circulating activin A levels are associated with impaired myocardial glucose metabolism and high LVMV-ratio in patients with uncomplicated T2D, reflecting a potential detrimental role in early human diabetic cardiomyopathy. TRIAL REGISTRATION NUMBER: Current Controlled Trials SRCTN53177482.

Parametric imaging of myocardial viability using ¹5O-labelled water and PET/CT: comparison with late gadolinium-enhanced CMR.

PURPOSE: The perfusable tissue index (PTI) is a marker of myocardial viability. Recent technological advances have made it possible to generate parametric PTI images from a single [(15)O]H(2)O PET/CT scan. The purpose of this study was to validate these parametric PTI images. METHODS: The study population comprised 46 patients with documented or suspected coronary artery disease who were studied with [(15)O]H(2)O PET and late gadolinium-enhanced (LGE) cardiac magnetic resonance imaging (CMR). RESULTS: Of the 736 myocardial segments included, 364 showed some degree of LGE. PTI and perfusable tissue fraction (PTF) diminished with increasing LGE. The areas under the curve of the PTI and PTF, used to predict (near) transmural LGE on CMR, were 0.86 and 0.87, respectively. Optimal sensitivity and specificity were 91 % and 73 % for PTI and 69 % and 87 % for PTF, respectively. CONCLUSION: PTI and PTF assessed with a single [(15)O]H(2)O scan can be utilized as markers of myocardial viability in patients with coronary artery disease.

Association of plasma osteoprotegerin and adiponectin with arterial function, cardiac function and metabolism in asymptomatic type 2 diabetic men.

BACKGROUND: Osteoprotegerin (OPG), a soluble member of the tumor necrosis factor receptor superfamily, is linked to cardiovascular disease. Negative associations exist between circulating OPG and cardiac function. The adipocytokine adiponectin (ADPN) is downregulated in type 2 diabetes mellitus (T2DM) and coronary artery disease and shows an inverse correlation with insulin sensitivity and cardiovascular disease risk. We assessed the relationship of plasma OPG and ADPN and arterial function, cardiac function and myocardial glucose metabolism in T2DM. METHODS: We included 78 asymptomatic men with uncomplicated, well-controlled T2DM, without inducible ischemia, assessed by dobutamine-stress echocardiography, and 14 age-matched controls. Cardiac function was measured by magnetic resonance imaging, myocardial glucose metabolism (MMRglu) by 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography. OPG and ADPN levels were measured in plasma. RESULTS: T2DM patients vs. controls showed lower aortic distensibility, left ventricular (LV) volumes, impaired LV diastolic function and MMRglu (all P < 0.05). In T2DM men vs. controls, OPG levels were higher (P = 0.02), whereas ADPN concentrations were decreased (P = 0.04). OPG correlated inversely with aortic distensibility, LV volumes and E/A ratio (diastolic function), and positively with LV mass/volume ratio (all P < 0.05). Regression analyses showed the associations with aortic distensibility and LV mass/volume ratio to be independent of age-, blood pressure- and glycated hemoglobin (HbA1c). However, the associations with LV volumes and E/A ratio were dependent of these parameters. ADPN correlated positively with MMRglu (P < 0.05), which, in multiple regression analysis, was dependent of whole-body insulin sensitivity, HbA1c and waist. CONCLUSIONS: OPG was inversely associated with aortic distensibility, LV volumes and LV diastolic function, while ADPN was positively associated with MMRglu. These findings indicate that in asymptomatic men with uncomplicated T2DM, OPG and ADPN may be markers of underlying mechanisms linking the diabetic state to cardiac abnormalities. TRIAL REGISTRATION: Current Controlled Trials ISRCTN53177482.

[Endocrine side effects of checkpoint inhibitors]. / Endocriene bijwerkingen van checkpointremmers.

Checkpoint inhibition has emerged as a promising therapeutic strategy for several types of cancer. Immune-related adverse effects (irAEs) commonly involve the endocrine system. Distinguishing endocrine side effect-related symptoms from disease progression or treatment-related toxicity can be challenging. If not recognized in time, endocrine irAEs may be life-threatening. As the use of checkpoint inhibitors is expected to increase, there is a need for more awareness of endocrine irAEs amongst health care professionals. We describe three cases that illustrate the importance of timely recognition, patient education and the management of endocrinopathies. Two patients who were treated with the checkpoint inhibitor ipilimumab developed hypophysitis and subsequent episodes of hypocortisolism. These cases underline both the frequency of diagnostic delay and the importance of patient education with regard to glucocorticoid stress dosage. The third patient presented with diabetes mellitus after administration of nivolumab. A multidisciplinary approach is warranted to ensure optimal care for patients with endocrine irAEs.

Palmitic acid increases pro-oxidant adaptor protein p66Shc expression and affects vascularization factors in angiogenic mononuclear cells: Action of resveratrol.

A defect in neo-vascularization process involving circulating angiogenic mononuclear cells (CACs) dysfunction is associated with diabetes. We showed that oxidative stress was elevated in CACs cultured from blood of individuals with metabolic syndrome (MetS) and diabetes. We then assessed the action of palmitic acid (PA), a deregulated and increased NEFA in metabolic disorders, focusing on its oxidant potential. We observed that the phyto-polyphenol resveratrol normalized oxidative stress both in CACs isolated from MetS patients or treated with PA. Resveratrol further decreased the deleterious action of PA on gene expression of vascularization factors (TNFα, VEGF-A, SDF1α, PECAM-1, VEGFR2, Tie2 and CXCR4) and improved CAC motility. Particularly, resveratrol abolished the PA-induced over-expression of the pro-oxidant protein p66Shc. Neither KLF2 nor SIRT1, previously shown in resveratrol and p66Shc action, was directly involved. Silencing p66Shc normalized PA action on VEGF-A and TNFα specifically, without abolishing the PA-induced oxidative stress, which suggests a deleterious role of p66Shc independently of any major modulation of the cellular oxidative status in a high NEFA levels context. Besides showing that resveratrol reverses PA-induced harmful effects on human CAC function, certainly through profound cellular modifications, we establish p66Shc as a major therapeutic target in metabolic disorders, independent from glycemic control.

Effect of type 2 diabetes mellitus on epicardial adipose tissue volume and coronary vasomotor function.

Patients with coronary artery disease and/or type 2 diabetes mellitus (DM) generally exhibit more epicardial adipose tissue (EAT) than healthy controls. Recently, it has been proposed that EAT affects vascular function and structure by secreting proinflammatory and vasoactive substances, thereby potentially contributing to the development of cardiovascular disease. In the present study, the interrelation of EAT, coronary vasomotor function, and coronary artery calcium was investigated in patients with and without DM, who were evaluated for coronary artery disease. Myocardial blood flow (MBF) was assessed at rest and during adenosine-induced hyperemia using [(15)O]-water positron emission tomography combined with computed tomography to quantify coronary artery calcium and EAT in 199 patients (46 with DM). In this cohort (mean age 58 ± 10 years), the patients with DM had a greater body mass index, heart rate, and systolic blood pressure at rest (all p <0.05). Coronary artery calcium and the EAT volumes were comparable between those with and without DM. Both patient groups showed comparable MBF at rest and coronary vascular resistance. A lower hyperemic MBF and coronary flow reserve (CFR) and greater hyperemic coronary vascular resistance (all p <0.05) was observed in the patients with DM. A pooled analysis showed a positive association of EAT volume with hyperemic coronary vascular resistance but not with the MBF at rest, hyperemic MBF, or coronary vascular resistance at rest. In the group analysis, the EAT volume was inversely associated with hyperemic MBF (r = -0.16, p = 0.05) and CFR (r = -0.17, p = 0.04) and positively with hyperemic coronary vascular resistance (r = 0.26, p = 0.002) only in patients without DM. Multivariate regression analysis, adjusted for age, gender, and body mass index, showed an independent association between the EAT volume and hyperemic MBF (ß = -0.16, p = 0.02), CFR (ß = -0.16, p = 0.04), and hyperemic coronary vascular resistance (ß = 0.25, p <0.001) in the non-DM group. In conclusion, these results suggest a role for EAT in myocardial microvascular dysfunction; however, once DM has developed, other factors might be more dominant in contributing to impaired myocardial microvascular dysfunction.

Cardioprotective properties of omentin-1 in type 2 diabetes: evidence from clinical and in vitro studies.

CONTEXT: Adipokines are linked to the development of cardiovascular dysfunction in type 2 diabetes (DM2). In DM2-patients, circulating levels of omentin-1, an adipokine preferentially expressed in epicardial adipose tissue, are decreased. This study investigated whether omentin-1 has a cardioprotective function. METHODS: Omentin-1 levels in plasma and cardiac fat depots were determined in DM2-patients versus controls. Moreover, the relation between omentin-1 levels and cardiac function was examined in men with uncomplicated DM2. Finally, we determined whether omentin-1 could reverse the induction of cardiomyocyte dysfunction by conditioned media derived from epicardial adipose tissue from patients with DM2. RESULTS: Omentin-1 was highly expressed and secreted by epicardial adipose tissue, and reduced in DM2. Circulating omentin-1 levels were lower in DM2 versus controls, and positively correlated with the diastolic parameters early peak filling rate, early deceleration peak and early deceleration mean (all P<0.05). The improved diastolic function following pioglitazone treatment associated with increases in omentin-1 levels (P<0.05). In vitro, exposure of cardiomyocytes to conditioned media derived from epicardial adipose tissue from patients with DM2 induced contractile dysfunction and insulin resistance, which was prevented by the addition of recombinant omentin. CONCLUSION: These data identify omentin-1 as a cardioprotective adipokine, and indicate that decreases in omentin-1 levels could contribute to the induction of cardiovascular dysfunction in DM2.