Long-term observational study on the impact of GLP-1R agonists on lung function in diabetic patients.

INTRODUCTION: Preclinical research suggests a role of Glucagon Like Peptide-1 Receptors (GLP-1R) on the regulation of human bronchial tone. We investigated the effect of GLP-1R agonists on lung function of Type 2 Diabetes Mellitus (T2DM) population without co-existing chronic obstructive respiratory disorders. METHODS: This was a prospective cohort study that examined change in lung function measurements over two years of T2DM patients (n = 32) treated with metformin monotherapy (control cohort), metformin plus GLP-1R agonists (GLP-1R agonists cohort), or metformin plus insulin (insulin cohort). RESULTS: After 24 months of treatment, the forced expiratory volume in 1 s (FEV1) significantly (p < 0.05) increased from baseline in the GLP-1R agonists cohort (218 ml [95%CI 88-246]), but not in the control and insulin cohorts (94 ml [95%CI -28 - 216] and 26 ml [95%CI -174 - 226], respectively; p > 0.05 vs. baseline). The average increase in FEV1 in the GLP-1R agonists cohort was significantly greater than that in the control and insulin cohorts (delta: 110 ml [95%CI 18-202] and 177 ml [95%CI 85-270], respectively, p < 0.05). The forced vital capacity (FVC) also increased significantly more in the GLP-1R agonists cohort than in the control and insulin cohorts (overall delta FVC: 183 ml [95%CI 72-295], p < 0.05). The maximal expiratory flow at 50-75% significantly (p < 0.05) improved from baseline in the GLP-1R agonists cohort, but not in the control and insulin cohorts (p > 0.05). CONCLUSION: Our preliminary results suggest a potential new therapeutic perspective to treat airway disorders with GLP-1R agonists.

Serum glucocorticoid inducible kinase (SGK)-1 protects endothelial cells against oxidative stress and apoptosis induced by hyperglycaemia.

Diabetic hyperglycaemia causes endothelial dysfunction mainly by impairing endothelial nitric oxide (NO) production. Moreover, hyperglycaemia activates several noxious cellular pathways including apoptosis, increase in reactive oxygen species (ROS) levels and diminishing Na(+)-K(+) ATPase activity which exacerbate vascular damage. Serum glucocorticoid kinase (SGK)-1, a member of the serine/threonine kinases, plays a pivotal role in regulating NO production through inducible NO synthase activation and other cellular mechanisms. Therefore, in this study, we aimed to investigate the protective role of SGK-1 against hyperglycaemia in human umbilical endothelial cells (HUVECs). We used retrovirus to infect HUVECs with either SGK-1, SGK-1Δ60 (lacking of the N-60 amino acids-increase SGK-1 activity) or SGK-1Δ60KD (kinase-dead constructs). We tested our hypothesis in vitro after high glucose and glucosamine incubation. Increase in SGK-1 expression and activity (SGK-1Δ60) resulted in higher production of NO, inhibition of ROS synthesis and lower apoptosis in endothelial cell after either hyperglycaemia or glucosamine treatments. Moreover, in this study, we showed increased GLUT-1 membrane translocation and Na(+)-K(+) ATPase activity in cell infected with SGK-1Δ60 construct. These results suggest that as in endothelial cells, an increased SGK-1 activity and expression reduces oxidative stress, improves cell survival and restores insulin-mediated NO production after different noxae stimuli. Therefore, SGK-1 may represent a specific target to further develop novel therapeutic options against diabetic vascular disease.

Generalized impairment of vasodilator reactivity during hyperinsulinemia in patients with obesity-related metabolic syndrome.

Defective insulin-dependent vasodilation might contribute importantly to metabolic and vascular abnormalities of the metabolic syndrome (MetS). However, despite extensive investigation, the precise mechanisms involved in insulin's vasoactive effects have not been fully elucidated. Therefore, this study sought to better characterize insulin's physiological actions on vascular reactivity and their potential derangement in the MetS. Forearm blood flow responses to graded doses of acetylcholine, sodium nitroprusside, and verapamil were assessed by strain-gauge plethysmography in patients with obesity-related MetS (n = 20) and in matched controls (n = 18) before and after intra-arterial infusion of insulin (0.2 mU·kg(-1)·min(-1)). Possible involvement of increased oxidative stress in the impaired insulin-stimulated vasodilator responsiveness of patients with MetS (n = 12) was also investigated using vitamin C (25 mg/min). In control subjects, significant potentiation of the vasodilator responses to acetylcholine, nitroprusside, and verapamil was observed after insulin infusion (all P < 0.05). However, no significant change in vasodilator reactivity to either of these drugs was observed following hyperinsulinemia in patients with MetS (all P > 0.05). Interestingly, administration of vitamin C to patients with MetS during hyperinsulinemia significantly enhanced the vasodilator responsiveness to acetylcholine, nitroprusside, and verapamil (all P < 0.05 vs. hyperinsulinemia alone). In conclusion, insulin exerts a generalized facilitatory action on vasodilator reactivity, and this effect is impaired in patients with MetS likely because of increased oxidative stress. Given the importance of vasodilator reactivity in affecting glucose disposal and vascular homeostasis, this defect may then contribute to the development of metabolic and vascular complications in insulin-resistant states.

Adiponectin isoforms in elderly patients with or without coronary artery disease.

OBJECTIVES: To study the distribution of adiponectin isoforms in a group of very old patients. DESIGN: Cross-sectional. SETTING: Geriatric ambulatory clinic of the Department of Medicine at Policlinico "Tor Vergata." PARTICIPANTS: One hundred eight elderly adults (mean age 85.0+/-3.2) with or without a history of a previous myocardial infarction as proof of established coronary artery disease (CAD) at least 3 months before entry into the study. Accordingly, subjects were divided into CAD positive (CAD+, n=50) and CAD negative (CAD-, n=58). MEASUREMENT: Assessment of adiponectin isoforms along with metabolic, lipid, and inflammatory profiles. RESULTS: CAD+ subjects had significantly higher levels of total adiponectin (Tot-Ad) and low-molecular-weight adiponectin (LMW-Ad) than CAD- subjects (P=.008 for both). LMW-Ad and high-sensitivity C-reactive protein were positively correlated, even after adjustment for waist circumference, sex, glomerular filtration rate, and presence of diabetes mellitus (correlation coefficient (r)=0.25, P=.05). This association was not confirmed when CAD+ subjects were analyzed alone. A positive association was found in CAD+ subjects between brain natriuretic peptide (BNP), high-molecular-weight adiponectin (HMW-Ad), and Tot-Ad (r=0.798 and r=0.795, P<.001 for all) but not LMW-Ad. CONCLUSION: Distribution of adiponectin isoforms differed in populations of elderly subjects according to the presence of coronary atherosclerosis. The data support the hypothesis for a protective role of LMW-Ad during aging, although additional studies are needed to definitively clarify whether LMW-Ad plays a protective role in older people with a history of CAD.

Early vascular and metabolic effects of rosuvastatin compared with simvastatin in patients with type 2 diabetes.

OBJECTIVE: To compare the short-term effects of rosuvastatin and simvastatin on insulin-resistance and endothelial dysfunction in middle-aged patients with type 2 diabetes and mild untreated dyslipidemia. METHODS AND DESIGN: 29 Subjects randomly assigned to rosuvastatin 20mg/daily or simvastatin 20mg/daily for 4 weeks. Following data collected both pre- and post-treatment: fasting glucose, lipids, hs CRP, TNF-alpha, insulin sensitivity measured with euglycemic-hyperinsulinemic clamp and flow-mediated dilation with brachial artery reactivity technique. RESULTS: Both treatments markedly reduced LDL cholesterol (p<0.001 for both). Insulin sensitivity did not change from relative baseline values in both groups, as well as fasting glucose and adiponectin. Simvastatin significantly improved flow-mediated dilation (p<0.01), to a greater extent than in patients taking rosuvastatin (p=0.09). We found no association between flow-mediated dilation improvement, LDL reduction and changes in hs CRP levels. CONCLUSION: In type 2 diabetic individuals rosuvastatin was less effective than simvastatin at improving endothelium-dependent vasodilation within one month, without affecting insulin-resistance, adiponectin levels and inflammation.

Metabolic syndrome and risk of pulmonary involvement.

Metabolic syndrome (MS) is a complex disorder recognized clinically by the findings of abdominal obesity, elevated triglycerides, atherogenic dyslipidaemia, elevated blood pressure, high blood glucose and/or insulin resistance. It is associated with a pro-thrombotic and a pro-inflammatory state. A growing body of evidence suggests that individuals in the community with moderate airflow limitation may have co-existing systemic inflammation with this background. Therefore, we examined a population of 237 patients with metabolic disorder for the concomitant presence of functional pulmonary involvement, as assessed by FEV(1) and FVC impairment. Criteria for the identification of the MS included 3 or more of the following: waist circumference: (>102 cm in men, >88 cm in women), triglycerides levels (> or =150 mg/dl), high-density lipoprotein cholesterol levels (<40 mg/dl in men, <50 mg/dl in women), blood pressure (> or =135/> or =85 mmHg), and fasting glucose levels (>100 mg/dl). 119 subjects were diagnosed MS. Non-smokers patients suffering from MS presented lower spirometric values, with a trend to ventilatory restrictive more than obstructive pattern. Also in smokers patients with MS there was a trend to harmonic decrease in FEV(1) and FVC but not in FEV(1)/FVC ratio, although the changes did not reach statistical significance. Mainly abdominal circumference, and also insulin resistance were retained as independent predictors of both FEV(1) and FVC changes. However, HDL-C was the strongest predictor of FEV(1) and FVC changes, with an inverse association.

Fish oil supplementation improves endothelial function in normoglycemic offspring of patients with type 2 diabetes.

OBJECTIVE: Offspring of patients with type 2 diabetes (OPDs) exhibits endothelial dysfunction (ED) associated with a chronic inflammatory state. N-3 polyunsaturated fatty acids (n-3 PUFA) may have antioxidant and anti-inflammatory properties that are beneficial for cardiovascular and metabolic health. Therefore, in the present study, we tested the hypothesis that dietary supplementation with fish oil rich in n-3 PUFA may improve ED in otherwise healthy OPDs. METHODS AND DESIGN: A double-blind, placebo-controlled trial was conducted with 50 OPDs. Participants were randomized to treatment with either placebo or n-3 PUFA (2g/day) for 12 weeks. Before and after treatment we evaluated endothelial function (using flow-mediated dilation (FMD) of the brachial artery), circulating inflammatory markers (adiponectin, TNF-alpha, and high sensitivity-CRP), and insulin resistance (QUICKI). RESULTS: No significant changes were observed in study outcomes in subjects treated with placebo. By contrast, when compared with baseline values, subjects treated with n-3 PUFA had significant improvement in FMD (9.1+/-5.8% vs. 11.7+/-4.4%, p=0.02) that was accompanied by decreased plasma triglycerides (117+/-73mg/dl vs. 86+/-44mg/dl, p=0.001) and TNF-alpha levels (8.9+/-2.3pg/ml vs. 6.8+/-2.7pg/ml, p=0.001), and a trend towards increased plasma adiponectin levels (7.8+/-4.5microg/ml vs. 9.5+/-5.1microg/ml, p=0.09). When data were analyzed by multiple regression analysis, decreased TNF-alpha after treatment with n-3 PUFA predicted increased FMD. CONCLUSION: Dietary supplementation with n-3 PUFA significantly improved endothelial function and reduced pro-inflammatory markers in OPDs. Thus, fish oil consumption may have beneficial cardiovascular and metabolic health effects in otherwise healthy subjects predisposed to diabetes and its vascular complications.