Analysis of MTNR1B gene polymorphisms in relationship with IRS2 gene variants, epicardial fat thickness, glucose homeostasis and cognitive performance in the elderly.

ABSTARCT Genome-wide association studies pinpointed common variants in or near the MTNR1B gene encoding MT2 melatonin receptor to be strongly associated with fasting glucose levels. IRS2 gene polymorphisms impact insulin resistance and epicardial fat (EF) thickness, which in turn is correlated with visceral adiposity, cognitive ability and risk for metabolic plus cardiovascular disease. We aimed to discover the interactions between MTNR1B and IRS2 gene polymorphisms, insulin sensitivity, EF thickness and cognitive performance in the elderly. In 60 subjects aged 60 years and older, we evaluated five single nucleotide polymorphisms (SNPs) within the MTNR1B locus (rs10830962, rs4753426, rs12804291, rs10830963, rs3781638), the Gly1057Asp variant of IRS2 gene (rs1805097), biochemical parameters, cognitive performance by the Mini Mental State Examination (MMSE) and EF thickness by transthoracic echocardiography. We found that MTNR1B and IRS2 gene variants impacted EF thickness, lipid profile and glucose homeostasis. IRS2 but not MTNR1B variants impacted MMSE scores. In conclusion, MTNR1B SNPs interact with IRS2 gene variant, correlate with the amount of epicardial adipose tissue and impact glucose homeostasis and lipid profile influencing cardiometabolic risk.

Short-term effects of glucagon-like peptide 1 (GLP-1) receptor agonists on fat distribution in patients with type 2 diabetes mellitus: an ultrasonography study.

AIMS: Glucagon-like peptide 1 receptor agonists (GLP-1 RA) induce weight loss and reduction in adipose tissue, but the effects of GLP-1 RA on the distribution of fat deposits have been poorly investigated. METHODS: In 25 patients with type 2 diabetes (16 females and 9 males, mean age 63.5 ± 8.8 years), treated with GLP-1 RA (exenatide, n. 12; liraglutide, n.13), both before and 3 months after starting treatment, an abdominal ultrasonographic scan, with Doppler of renal arteries, and echocardiography were performed. Subcutaneous fat width (peri-umbilical and sub-xiphoid), deep fat deposits (pre-aortic, peri-renal, and epicardial), and renal resistive index (RI) were evaluated. RESULTS: GLP-1 RA induced highly significant (p < 0.001) decrease in BMI and in fat thickness at all the assessed sites, without differences between exenatide and liraglutide treatment. A slight decrease in RI (p = 0.055) was also found. The percent changes of fat thickness was different between sites (p < 0.025), and the changes in subcutaneous deposits showed no significant correlation (p = 0.064) with those of deep fat deposits. CONCLUSIONS: A short course of treatment with GLP-1 RA, besides weight loss, induces a redistribution of adipose tissue deposits, possibly contributing to a better cardiovascular risk profile in patients with type 2 diabetes mellitus.

An association study between epicardial fat thickness and cognitive impairment in the elderly.

The amount of fat surrounding the heart, called epicardial adipose tissue (EAT), is a marker of cardiometabolic risk and correlates with the quantity of visceral adipose tissue (VAT). The amount of VAT is associated with an increased risk of cardiovascular and cerebrovascular disease and with cognitive impairment. We aimed to evaluate the association between EAT thickness as a measure of VAT and cognitive function. In 71 elderly subjects (mean age 72.7 ± 7.1 yr) we measured EAT thickness through transthoracic echocardiography, assessed the metabolic profile through evaluation of biochemical parameters, and estimated the cognitive function via the Mini Mental State Examination (MMSE). We found that greater EAT thickness was associated with lower cognitive performance evaluated by MMSE (P < 0.01) independently of the presence or absence of metabolic syndrome or obesity. Lower MMSE results were also associated with the presence of metabolic syndrome (P < 0.01), elevated HOMA index (P < 0.01), and high BMI values (P < 0.01). The results of mediation analysis confirmed that the total effect of metabolic syndrome, HOMA, and BMI on MMSE is mainly explained by an indirect effect through EAT thickness. In conclusion, increased EAT thickness assessed by transthoracic echocardiography is associated with deficient results of psychometric tests assessing cognitive performance and may consistently foresee impairment of cognition in the elderly.

Effects of hypercapnia on peripheral vascular reactivity in elderly patients with acute exacerbation of chronic obstructive pulmonary disease.

Blood acid-base imbalance has important effects on vascular reactivity, which can be related to nitric oxide (NO) concentration and increased during hypercapnia. Release of NO seems to be linked to H+ and CO2 concentration and to exacerbation of chronic obstructive pulmonary disease (COPD), a common medical condition in the elderly. Flow-mediated dilation (FMD), a valuable cardiovascular risk indicator, allows assessment of endothelial-dependent vasodilation, which is to a certain extent mediated by NO. We investigated the effects of hypercapnia and acid-base imbalance on endothelial-dependent vasodilation by measurement of FMD in 96 elderly patients with acute exacerbation of COPD. Patients underwent complete arterial blood gas analysis and FMD measurement before (phase 1) and after (phase 2) standard therapy for acute exacerbation of COPD and recovery. Significant differences between phase 1 and phase 2 were observed in the mean values of pH (7.38±0.03 versus 7.40±0.02, P<0.001), pO2 (59.6±4.9 mmHg versus 59.7±3.6 mmHg, P<0.001), pCO2 (59.3±8.63 mmHg versus 46.7±5.82 mmHg, P<0.001), FMD (10.0%±2.8% versus 8.28%±2.01%, P<0.001) and blood flow rate (1.5±0.3 m/s versus 1.5±0.3 m/s, P=0.001). FMD values were positively correlated with pCO2 values (r=0.294, P=0.004) at baseline. A significant correlation was also found between relative changes in FMD and pCO2 levels, passing from phase 1 to phase 2 (r=0.23, P=0.023). Patients with higher baseline endothelium-dependent vasodilation as evaluated by FMD showed greater modification with regard to pCO2 changes (2.6±1.39 versus 1.59±1.4, P=0.012). In conclusion, endothelium-dependent vasodilation as evaluated by FMD was elevated during hypercapnia, and varied significantly according to pCO2 changes in patients with higher baseline levels, suggesting that vascular reactivity in acute COPD exacerbations in the elderly depends on integrity of the vascular endothelium.

Influence of the Gly1057Asp variant of the insulin receptor substrate 2 (IRS2) on insulin resistance and relationship with epicardial fat thickness in the elderly.

Insulin receptor substrate 2 (IRS2) plays a crucial role in the regulation of insulin signaling. Several polymorphisms of the gene encoding IRS2 have been identified. The variant causing Gly1057Asp substitution is relatively frequent in humans and its impact on insulin sensitivity seems to be dependent on age and body weight. The aim of our study was to evaluate the relationships between Gly1057Asp variant and insulin sensitivity assessed by HOMA, and adiposity evaluated by measurement of epicardial fat (EpiF) thickness in the elderly. We studied 87 subjects, 42 men and 45 women, mean age±SD: 74.23±7.24years. In the subjects carrying the Gly1057Asp variant of the IRS2 gene we found higher HOMA index values (3.40±1.14 vs. 2.21±1.25, p<0.001) and increased epicardial adipose tissue (11.77±1.65 vs. 10.43±1.93mm, p<0.001) compared to wild type subjects. Univariate linear regression analyses evidenced that HOMA index was correlated with BMI (beta=0.152, p<0.001), fasting plasma glucose (beta=0.018, p=0.002), LDL cholesterol (beta=0.008, p=0.024), total cholesterol (beta=0.007, p=0.039), weight (beta=0.054, p<0.001), presence of Gly1057Asp variant (beta=1.185, p<0.001) and EpiF thickness (beta=0.540, p<0.001). In multivariate analysis HOMA index was still associated with the presence of the Gly1057Asp variant of the IRS-2 gene (beta=0.568, p=0.002) and with EpiF thickness (beta=0.414, p<0.001). Furthermore, a statistically significant positive correlation between EpiF thickness and HOMA was found (r=0.773, p<0.001) and this was not different between wild type control subjects and carriers of Gly1057Asp variant of the IRS2 gene (p=0.718). Similar results were obtained in comparing subjects with normal fasting glucose levels. In conclusion, in our elderly subjects the presence of the allelic variant Gly1057Asp of IRS2 gene was associated to the degree of insulin resistance assessed by HOMA index and with EpiF thickness, independently from the extent of obesity, suggesting its contribution to global cardiometabolic risk.

Epicardial adipose tissue and idiopathic deep venous thrombosis: an association study.

OBJECTIVE: Epicardial fat (EpiF) reflects abdominal visceral adiposity and visceral fat plays an important role in the development of an unfavorable metabolic and atherosclerosis risk profile. An increased cardiovascular risk has been evidenced in patients with deep venous thrombosis (DVT). Advancing age is characterized by alterations of body fat mass and function In this study we studied the association between EpiF, DVT, age, obesity and other atherosclerosis risk factors. METHODS AND RESULTS: 77 patients were recruited: 44 men and 33 women, 38 without DVT (65.9 ± 16.3 years, range 26-92 years) and 39 with DVT (65.4 ± 17.2 years, range 28-90 years). The study design was balanced for established atherosclerosis risk factors (gender, obesity, smoking habits, dyslipidemia, diabetes mellitus, arterial hypertension), for previous cardiovascular events, for use of statins and platelet anti-aggregating agents. Multivariate regression model and RECPAM regression tree were used to study the association between EpiF thickness and the other potential risk factors. Patients with DVT showed a thicker EpiF with respect to those without DVT (12 ± 2 mm vs. 9 ± 2 mm respectively, p < 0.001). Multivariate linear regression model showed that DVT, obesity and age were positively associated with EpiF thickness after adjusting for the established atherosclerosis risk factors. Furthermore, the RECPAM analysis was performed to evaluate interactions between DVT, age and obesity: four main distinct and homogeneous subgroups of patients in terms of EpiF thickness were identified. The most important variable in partitioning patients was represented, as expected, by DVT (p < 0.001) followed by age (p = 0.004), while obesity did not contribute to the model as well as the other atherosclerosis risk factors. Patients with DVT and older than 41 years of age had higher EpiF thickness in respect of patients with DVT and younger than 41 years of age. In patients without DVT the estimated cut-off age was 50 years, and older patients had thicker EpiF in respect of patients younger than 50 years of age. CONCLUSION: DVT should be considered as strongly associated with EpiF thickness. Advancing age (with or without spontaneous DVT) is significantly associated with an increased EpiF thickness. The measurement of EpiF thickness, a valuable marker of cardio-metabolic risk, may represent a useful and reliable method to evaluate cardiovascular risk in patients with idiopathic deep phlebothrombosis.

Idiopathic deep venous thrombosis and arterial endothelial dysfunction in the elderly.

Arterial and venous thrombosis have always been regarded as different pathologies and epidemiological studies have examined the association between venous thrombosis and indicators of atherosclerosis and/or arterial thromboembolic events. We measured the flow-mediated dilation (FMD), a well-known marker of arterial endothelial dysfunction, in young-middle-aged and old-aged patients with and without unprovoked deep venous thrombosis (DVT). The aim of this study was to investigate whether DVT was a significant predictor for impaired FMD, considering all the patients and young-middle-aged (age < 65 years) and old-aged (age ≥ 65 years) patients separately. FMD was measured in the brachial artery on a population of 120 subjects with the same atherosclerosis risk factors, 68 male and 52 female, 70 young-middle-aged subjects (mean age ± SD 49.5 ± 10.5 years) and 50 old-aged subjects (76.2 ± 7.7 years). Patients with DVT showed a significant decrease of FMD compared to patients without DVT (6.8 ± 5.5% vs. 10.9 ± 3.5%, p < 0.001). Moreover, old-aged patients showed a significant decrease of FMD compared to the young-middle-aged subjects (7.4 ± 4.1% vs. 9.8 ± 5.3%, p = 0.005). In the whole study population, DVT was strongly associated with FMD (risk factors adjusted ß = -4.14, p < 0.001). A significant interaction between age and the presence of DVT on predicting FMD was found (p = 0.003) suggesting a differential behavior of DVT as predictor of FMD. In young-middle-aged group, multivariate model confirmed that DVT was the most significant predictor of continuous FMD (ß = -6.06, p < 0.001). On the contrary, DVT was no more a predictor of FMD in the old age group (ß = -0.73, p = 0.556). Furthermore, old-aged patients without DVT showed a statistically significant decrease of FMD compared to the young-middle-aged subjects without DVT (8.2 ± 2.1% vs. 12.6 ± 2.7%, p<0.001) and old-aged patients with DVT showed a not statistically significant decrease of the FMD compared to the young-middle-aged patients with DVT (6.7 ± 5.3% vs. 6.8 ± 5.7%, p = 0.932). In conclusion, young-middle-aged patients with spontaneous DVT show an impaired FMD, whereas this impairment in old-aged subjects is evident independently from the presence or absence of DVT. Aging per se may be associated with physiologic abnormalities in the systemic arteries and with endothelial dysfunction.

Antiphase signalling in the neuroendocrine-immune system in healthy humans.

BACKGROUND: Any quantity varying in the spatial-temporal dimension may be considered as a signal. Human lymphocyte cell surface molecules and subsets present circadian variation and this variation may represent a kind of signalling in the neuroendocrine-immune system. We have analyzed the dynamics of variation of specific lymphocyte subsets in healthy humans. SUBJECTS AND METHODS: In our study, lymphocyte subpopulation analyses were performed and cortisol, melatonin, GH and TSH serum levels were measured on blood samples collected every 4h for 24 hours from eleven healthy men, ages 35-53 years (mean=44±6SD). RESULTS: A clear circadian rhythm was validated for CD8 and cortisol with acrophase during the day and for CD3, CD4, melatonin, GH and TSH with acrophase at night. Cross-correlation showed that CD3 correlated positively with CD4 (ρ=0.67, P<0.05) and negatively with CD8 (ρ=-0.41, P<0.05), CD4 correlated positively with melatonin (ρ=0.90, P<0.05), GH (ρ=0.92, P<0.05) and TSH (ρ=0.71, P<0.05), negatively with CD8 (ρ=-0.90, P<0.05) and cortisol (ρ=-0.18, P<0.05), CD8 correlated positively with cortisol (ρ=0.38, P<0.05). DISCUSSION: The different profiles of nyctohemeral changes of lymphocyte cell surface molecules and specific lymphocyte subsets realize different relationships with the neuroendocrine hormones and might represent a way of signal transmission among the multiple components of the neuroendocrine-immune system.

Neuroendocrine-immune interactions in healthy aging.

AIM: The nervous, endocrine and immune systems are connected by shared neurotransmitters, hormones and cytokines. The function of these systems shows patterns of circadian rhythmicity and a number of age-related changes in the 24-h hormonal and non-hormonal rhythms have been found in older human beings. The aim of this study was to evaluate integration among the nervous, endocrine and immune systems in the elderly. METHODS: Cortisol and melatonin serum levels were measured and lymphocyte subpopulation analyses were performed on blood samples collected every 4 h for 24 h from 15 healthy young-middle-aged subjects (range 36-55 years, mean age±standard error [SE] 44.08±1.76) and 15 healthy old-aged subjects (range 67-79 years, mean age±SE 68.52±1.27). RESULTS: There was a statistically significant difference between the groups in the observed values of CD20 (total B cells higher in young-middle-aged subjects, P=0.02), CD25 (activated T cells with expression of the α-chain of interleukin-2 receptor, higher in elderly subjects, P=0.04) and DR+ T cells (activated T cells higher in elderly subjects, P=0.01). There were different correlations among lymphocyte subpopulations and hormone serum levels in young and middle-aged subjects in compared to old-aged subjects. In the group of young-middle-aged subjects, a clear circadian rhythm was validated for the time-qualified changes of all the factors studied. In the group of elderly subjects, a clear circadian rhythm was validated for the nyctohemeral changes of CD3 (with a phase delay of 3 h), CD8, CD4/CD8 ratio, CD16, CD25 (in opposite phase), cortisol (with a phase delay of 1 h) and melatonin. CONCLUSION: The results of the current study show that aging is associated with enhanced responsiveness of the T-cell compartment, impairment of B-cell compartment and alterations in temporal architecture and correlations of neuroendocrine-immune parameters.

Anti-tumor necrosis factor-α therapy and changes of flow-mediated vasodilatation in psoriatic and rheumatoid arthritis patients.

For a long time, the endothelial covering of the vessels has been considered an inert surface. On the contrary, the endothelial cells are active and dynamic elements in the interaction between blood and tissues. The control of the vessel basal tone is obtained by the complex balance between the relaxing and contracting endothelial factors. Previous clinical studies show that patients suffering from rheumatoid arthritis and other autoimmune rheumatologic pathologies are at high risk of death being prematurely affected by atherosclerosis and cardiovascular diseases. Blocking tumor necrosis factor (TNF)-α by biological drugs improves the endothelial function. The aim of our study was to evaluate the effects of two anti-TNF-α drugs (infliximab and etanercept) on the endothelial function by evaluating the flow-mediated dilatation (FMD), which was measured in the brachial artery before and after treatment and after 8-12 weeks. We enrolled 36 patients (average age 52 ± 9.8 years, 12 men and 24 women), 25 of them were affected by rheumatoid arthritis (RA) and 11 were affected by psoriatic arthritis (PsA) and they were divided into three groups: 10 patients were treated with etanercept, 13 patients were treated with infliximab, 13 patients were treated with DMARDs. We measured the common carotid intimal-medial thickness (ccIMT) and the endothelial function was evaluated by FMD measurement in the brachial artery, before treatment, 1 h after the beginning of treatment and after 8-12 weeks. No statistically significant difference between the three groups was found for the ultrasonographic evaluation of the carotid IMT. On the contrary, the differences between FMD values before and after the treatment in the patients treated with etanercept (13.1 ± 0.01 vs. 18.8 ± 0.01%, p < 0.01) and in the patients treated with infliximab (11.8 ± 0.09 vs. 16.7 ± 0.09%, p < 0.01) were statistically significant. Long-term evaluation for infliximab and etanercept was performed by comparing the FMD values, respectively, 8 and 12 weeks after the first treatment. After 8 weeks, FMD value was similar to the value recorded at enrollment in the infliximab group (11.9 ± 0.03 vs. 13.54 ± 0.04%, p = 0.236) and the FMD values in the etanercept group after 12 weeks showed a not statistically significant reduction of vasodilatating effect (13.01 ± 0.03 vs. 15.67 ± 0.02%, p = 0.197). In conclusion, the use of biological drugs in patients affected by autoimmune arthritis can modify the endothelial function, as indicated by the induced FMD changes, but the long-term effect tends to be considerably reduced.

Aging related changes of circadian rhythmicity of cytotoxic lymphocyte subpopulations.

BACKGROUND: Immunosenescence is a process that affects all cell compartments of the immune system and the contribution of the immune system to healthy aging and longevity is still an open question. Lymphocyte subpopulations present different patterns of circadian variation and in the elderly alteration of circadian rhythmicity has been evidenced. The aim of our study was to analyze the dynamics of variation of specific cytotoxic lymphocyte subsets in old aged subjects. METHODS: Lymphocyte subpopulation analyses were performed and cortisol serum levels were measured on blood samples collected every four hours for 24 hours from fifteen healthy male young-middle aged subjects (age range 36-55 years) and fifteen healthy male old aged subjects (age range 67-79 years). RESULTS: In healthy young-middle aged subjects CD20 were higher and at 06:00 h CD8+ dim correlated positively with CD16+ and positively with gammadeltaTCR+ cells, CD16 correlated positively with gammadeltaTCR+ cells At 18:00 h CD8+ dim correlated positively with CD16+ and positively with gammadeltaTCR+ cells, CD16+ correlated positively with gammadeltaTCR+ cells and a clear circadian rhythm was validated for the time-qualified changes of CD3+, CD4+, CD20+, CD25+ and HLA-DR+ cells with acrophase during the night and for the time-qualified changes of CD8+, CD8+ bright, CD8+ dim, CD16+ and gammadeltaTCR+ cells with acrophase during the day. In old aged subjects CD25, DR+ T cells and cortisol serum levels were higher, but there was no statistically significant correlation among lymphocyte subpopulations and a clear circadian rhythm was evidenced for time-qualified changes of CD3+ and CD25+ cells with acrophase during the night and for the time-qualified changes of CD8+ cells and cortisol with acrophase during the day. CONCLUSION: Our study has evidenced aging-related changes of correlation and circadian rhythmicity of variation of cytotoxic lymphocyte subpopulations that might play a role in the alteration of immune system function in the elderly.