206 research outputs found
Relationship between adipose tissue dysfunction, Vitamin D deficiency and the pathogenesis of non-alcoholic fatty liver disease
Non-alcoholic fatty liver disease ( NAFLD) is the most common chronic liver disease worldwide. Its pathogenesis is complex and not yet fully understood. Over the years many studies have proposed various pathophysiological hypotheses, among which the currently most widely accepted is the "multiple parallel hits" theory. According to this model, lipid accumulation in the hepatocytes and insulin resistance increase the vulnerability of the liver to many factors that act in a coordinated and cooperative manner to promote hepatic injury, inflammation and fibrosis. Among these factors, adipose tissue dysfunction and subsequent chronic low grade inflammation play a crucial role. Recent studies have shown that vitamin D exerts an immune-regulating action on adipose tissue, and the growing wealth of epidemiological data is demonstrating that hypovitaminosis D is associated with both obesity and NAFLD. Furthermore, given the strong association between these conditions, current findings suggest that vitamin D may be involved in the relationship between adipose tissue dysfunction and NAFLD. The purpose of this review is to provide an overview of recent advances in the pathogenesis of NAFLD in relation to adipose tissue dysfunction, and in the pathophysiology linking vitamin D deficiency with NAFLD and adiposity, together with an overview of the evidence available on the clinical utility of vitamin D supplementation in cases of NAFLD
Search for genetic variants in the p66Shc longevity gene by PCR-single strand conformational polymorphism in patients with early-onset cardiovascular disease.
Background: Among the possible candidate genes for atherosclerosis experimental data point towards the longevity gene p66(Shc). The p66(Shc) gene determines an increase of intracellular reactive oxygen species (ROS), affecting the rate of oxidative damage to nucleic acids. Knock-out p66(Shc-/-) mice show reduction of systemic oxidative stress, as well as of plasma LDL oxidation, and reduced atherogenic lesions. Thus, p66(Shc) may play a pivotal role in controlling oxidative stress and vascular dysfunction in vivo.
Methods: We searched for sequence variations in the p66(Shc) specific region of the Shc gene and its upstream promoter by PCR-SSCP in a selected group of early onset coronary artery disease ( CAD) subjects (n. 78, mean age 48.5 +/- 6 years) and in 93 long-living control subjects ( mean age 89 +/- 6 years).
Results: The analysis revealed two variant bands. Sequencing of these variants showed two SNPs: -354T > C in the regulatory region of p66(Shc) locus and 92C > T in the p66 specific region (CH2). Both these variants have never been described before. The first substitution partially modifies the binding consensus sequence of the SpI transcription factor, and was detected only in two heterozygous carriers (1 CAD subjects and 1 control subject). The 92C > T substitution in the CH2 region consists in an amino acid substitution at codon 31 (proline to leucine, P31L), and was detected in heterozygous status only in one CAD subject. No subjects homozygous for the two newly described SNPs were found.
Conclusion: Only two sequence variations in the p66(Shc) gene were observed in a total of 171 subjects, and only in heterozygotes. Our observations, in accordance to other studies, suggest that important variations in the p66(Shc) gene may be extremely rare and probably this gene is not involved in the genetic susceptibility to CAD
Strong association between non alcoholic fatty liver disease (NAFLD) and low 25(OH) vitamin D levels in an adult population with normal serum liver enzymes
<p>Abstract</p> <p>Background</p> <p>Hypovitaminosis D has been recently recognized as a worldwide epidemic. Since vitamin D exerts significant metabolic activities, comprising free fatty acids (FFA) flux regulation from the periphery to the liver, its deficiency may promote fat deposition into the hepatocytes. Aim of our study was to test the hypothesis of a direct association between hypovitaminosis D and the presence of NAFLD in subjects with various degree of insulin-resistance and related metabolic disorders.</p> <p>Methods</p> <p>We studied 262 consecutive subjects referred to the Diabetes and Metabolic Diseases clinics for metabolic evaluation. NAFLD (non-alcoholic fatty liver disease) was diagnosed by upper abdomen ultrasonography, metabolic syndrome was identified according to the Third Report of National Cholesterol Education Program/Adult Treatment Panel (NCEP/ATPIII) modified criteria. Insulin-resistance was evaluated by means of HOMA-IR. Fatty-Liver-Index, a recently identified correlate of NAFLD, was also estimated. Serum 25(OH)vitamin D was measured by colorimetric method.</p> <p>Results</p> <p>Patients with NAFLD (n = 162,61.8%) had reduced serum 25(OH) vitamin D levels compared to subjects without NAFLD (14.8 ± 9.2 vs 20.5 ± 9.7 ng/ml, p < 0.001, OR 0.95, IC 95% 0.92-0.98). The relationship between NAFLD and reduced 25(OH)vitamin D levels was independent from age, sex, triglycerides, high density lipoproteins (HDL) and glycaemia (p < 0.005) and Fatty Liver Index inversely correlated with low 25(OH) vitamin D regardless sex, age and HOMA-IR (p < 0.007).</p> <p>Conclusions</p> <p>Low 25(OH)vitamin D levels are associated with the presence of NAFLD independently from metabolic syndrome, diabetes and insulin-resistance profile.</p
Phenotypical heterogeneity linked to adipose tissue dysfunction in patients with type 2 diabetes
Adipose tissue (AT) inflammation leads to increased free fatty acid (FFA) efflux and ectopic fat deposition, but whether AT dysfunction drives selective fat accumulation in specific sites remains unknown. The aim of the present study was to investigate the correlation between AT dysfunction, hepatic/pancreatic fat fraction (HFF, PFF) and the associated metabolic phenotype in patients with Type 2 diabetes (T2D). Sixty-five consecutive T2D patients were recruited at the Diabetes Centre of Sapienza University, Rome, Italy. The study population underwent clinical examination and blood sampling for routine biochemistry and calculation of insulin secretion [homoeostasis model assessment of insulin secretion (HOMA-β%)] and insulin-resistance [homoeostasis model assessment of insulin resistance (HOMA-IR) and adipose tissue insulin resistance (ADIPO-IR)] indexes. Subcutaneous (SAT) and visceral (VAT) AT area, HFF and PFF were determined by magnetic resonance. Some 55.4% of T2D patients had non-alcoholic fatty liver disease (NAFLD); they were significantly younger and more insulin-resistant than non-NAFLD subjects. ADIPO-IR was the main determinant of HFF independently of age, sex, HOMA-IR, VAT, SAT and predicted severe NAFLD with the area under the receiver operating characteristic curve (AUROC)=0.796 (95% confidence interval: 0.65-0.94, P=0.001). PFF was independently associated with increased total adiposity but did not correlate with AT dysfunction, insulin resistance and secretion or NAFLD. The ADIPO-IR index was capable of predicting NAFLD independently of all confounders, whereas it did not seem to be related to intrapancreatic fat deposition; unlike HFF, higher PFF was not associated with relevant alterations in the metabolic profile. In conclusion, the presence and severity of AT dysfunction may drive ectopic fat accumulation towards specific targets, such as VAT and liver, therefore evaluation of AT dysfunction may contribute to the identification of different risk profiles among T2D patients
Effects of metformin and exercise training, alone or in association, on cardio-pulmonary performance and quality of life in insulin resistance patients
BACKGROUND:
Metformin (MET) therapy exerts positive effects improving glucose tolerance and preventing the evolution toward diabetes in insulin resistant patients. It has been shown that adding MET to exercise training does not improve insulin sensitivity. The aim of this study was to determine the effect of MET and exercise training alone or in combination on maximal aerobic capacity and, as a secondary end-point on quality of life indexes in individuals with insulin resistance.
METHODS:
75 insulin resistant patients were enrolled and subsequently assigned to MET (M), MET with exercise training (MEx), and exercise training alone (Ex). 12-weeks of supervised exercise-training program was carried out in both Ex and MEx groups. Cardiopulmonary exercise test and SF-36 to evaluate Health-Related Quality of Life (HRQoL) was performed at basal and after 12-weeks of treatment.
RESULTS:
Cardiopulmonary exercise test showed a significant increase of peak VO2 in Ex and MEx whereas M showed no improvement of peak VO2 (∆ VO2 [CI 95%] Ex +0.26 [0.47 to 0.05] l/min; ∆ VO2 MEx +0.19 [0.33 to 0.05] l/min; ∆ VO2 M -0.09 [-0.03 to -0.15] l/min; M vs E p < 0.01; M vs MEx p < 0.01; MEx vs Ex p = ns). SF-36 highlighted a significant increase in general QoL index in the MEx (58.3 ± 19 vs 77.3 ± 16; p < 0.01) and Ex (62.1 ± 17 vs 73.7 ± 12; p < 0.005) groups.
CONCLUSIONS:
We evidenced that cardiopulmonary negative effects showed by MET therapy may be counterbalanced with the combination of exercise training. Given that exercise training associated with MET produced similar effects to exercise training alone in terms of maximal aerobic capacity and HRQoL, programmed exercise training remains the first choice therapy in insulin resistant patients
Hypovitaminosis D is independently associated with metabolic syndrome in obese patients
Background: Metabolic syndrome (MS) and hypovitaminosis D represent two of the most diffuse condition worldwide, reaching pandemic proportions in industrialized countries, and are both strongly associated with obesity. This study set out to evaluate the presence of an independent association between hypovitaminosis D and MS in an adult population of obese subjects with/without MS. Methods: We recruited 107 consecutive obese subjects, 61 with MS (age(mean +/- SD) 45.3 +/- 13.3 years, BMI(mean +/- SD): 43.1 +/- 8.3 kg/m(2)) and 46 without MS (age: 41.8 +/- 11.5, p = n.s., BMI: 41.6 +/- 6.5 kg/m(2), p = n.s.) comparable for sex, BMI, waist circumference and body fat mass, evaluated by bioimpedentiometry. 25(OH) vitamin D-3 levels were measured by colorimetric method. Insulin resistance was estimated by fasting blood insulin, HOMA-IR and ISI. Results: Serum 25(OH) D3 levels were significantly lower in MS obese patients than in obese subjects without MS (median(range) 13.5(3.3-32) vs 17.4(5.1-37.4), p<0.007). Low 25(OH)D-3 levels correlated with glycaemia (p<0.007), phosphate (p<0.03), PTH (p<0.003) and the MS (p<0.001). Multivariate model confirmed that low 25(OH)D-3 levels were associated with the diagnosis of MS in obese patients independently from gender, age, serum PTH and body fat mass. After stratifying the study population according to 25(OH)D-3 concentrations, patients in the lowest quartile showed a markedly increased prevalence of MS compared to those in the highest quartile (OR = 4.1, CI 1.2-13.7, p = 0.02). Conclusions: A powerful association exists between hypovitaminosis D and MS in obese patients independently from body fat mass and its clinical correlates. This indicates that the association between low 25(OH)D-3 levels and MS is not merely induced by vitamin D deposition in fat tissue and reinforces the hypothesis that hypovitaminosis D represent a crucial independent determinant of MS.Background:Metabolic syndrome (MS) and hypovitaminosis D represent two of the most diffuse condition worldwide, reaching pandemic proportions in industrialized countries, and are both strongly associated with obesity. This study set out to evaluate the presence of an independent association between hypovitaminosis D and MS in an adult population of obese subjects with/without MS.Methods:We recruited 107 consecutive obese subjects, 61 with MS (age(mean±SD) 45.3±13.3 years, BMI(mean±SD): 43.1±8.3 kg/m2) and 46 without MS (age: 41.8±11.5, p = n.s., BMI:41.6±6.5 kg/m2, p = n.s.) comparable for sex, BMI, waist circumference and body fat mass, evaluated by bioimpedentiometry. 25(OH) vitamin D3 levels were measured by colorimetric method. Insulin resistance was estimated by fasting blood insulin, HOMA-IR and ISI.Results:Serum 25(OH)D3 levels were significantly lower in MS obese patients than in obese subjects without MS (median(range) 13.5(3.3-32) vs 17.4(5.1-37.4), p<0.007). Low 25(OH)D3 levels correlated with glycaemia (p<0.007), phosphate (p<0.03), PTH (p<0.003) and the MS (p<0.001). Multivariate model confirmed that low 25(OH)D3 levels were associated with the diagnosis of MS in obese patients independently from gender, age, serum PTH and body fat mass. After stratifying the study population according to 25(OH)D3 concentrations, patients in the lowest quartile showed a markedly increased prevalence of MS compared to those in the highest quartile (OR = 4.1, CI 1.2-13.7, p = 0.02).Conclusions:A powerful association exists between hypovitaminosis D and MS in obese patients independently from body fat mass and its clinical correlates. This indicates that the association between low 25(OH) D3 levels and MS is not merely induced by vitamin D deposition in fat tissue and reinforces the hypothesis that hypovitaminosis D represent a crucial independent determinant of MS. © 2013 Barchetta et al
Positive effects of Nordic Walking on anthropometric and metabolic variables in women with type 2 diabetes mellitus
Objectives. — Lack of physical activity predisposes people to chronic diseases including diabetes
mellitus, obesity, and coronary artery diseases. Identifying forms of physical activity is
warranted for prevention of these chronic diseases. Daily exercise has also been considered a
significant contributing factor in the management of type 2 diabetes. Nordic Walking is shown
to be easy to teach and learn, simple and adaptable to subjects with diabetes and metabolic
syndrome. Nordic Walking allows training of about 90% of body muscles in the active propulsion
phase, thus increasing energy expenditure by 30 to 50%. Aim of our study was to evaluate the
effects of Nordic Walking structured training in a group of female patients with type 2 diabetes,
looking at changes in anthropometric, metabolic and bioelectrical variables pre- and
post-activities. A follow-up of 6 months after the end of the program was also performed.
Equipment and methods. — Twenty women with type 2 diabetes, aged 40—65 years, were
enrolled. The participants were randomized in two groups: (1) 10 women in the Nordic Walking
active gr
Effects of metformin and exercise training, alone or in combination, on cardiac function in individuals with insulin resistance
Introduction: In patients affected by insulin resistance (IR), metformin (MET) therapy has been shown to exert its positive effects by improving glucose tolerance and preventing the evolution to diabetes. Recently, it was shown that the addition of metformin to physical training did not improve sensitivity to insulin or peak oxygen consumption (peak VO2). The purpose of this study was to establish the effect of metformin and exercise, separately or in combination, on systolic left ventricular (LV) function in individuals with IR.
Methods: Seventy-five patients with IR were enrolled and subsequently assigned to MET, combination MET and exercise, or exercise alone. The LV systolic and diastolic functions were evaluated with standard echocardiography tissue Doppler imaging (TDI) and speckle tracking echocardiography at baseline and after 12 weeks of treatment.
Results: MET, administered alone or in association with exercise, improved longitudinal LV function, as evidenced by an increase in systolic (S) wave on TDI, alongside increases in longitudinal global strain and strain rate in comparison to the group undergoing physical training alone. The traditional echocardiographic parameters showed no statistically significant differences among the three groups before or after the different cycles of therapy.
Conclusions: Treatment with MET, either with or without exercise, but not exercise alone, produced a significant increase in global longitudinal LV systolic function at rest. These findings validate the observation that the use of MET alone or in association with exercise has a crucial role to counteract the negative effects of IR on cardiovascular function
No effects of oral vitamin D supplementation on non-alcoholic fatty liver disease in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled trial
Background: Non-alcoholic fatty liver disease (NAFLD) is the most common hepatic disorder worldwide, reaching
prevalence up to 90 % in obese patients with type 2 diabetes (T2D), and representing an independent risk factor
for cardiovascular mortality. Furthermore, the coexistence of T2D and NAFLD leads to higher incidence of diabetes’
complications and additive detrimental liver outcomes. The existence of a close association between NAFLD and
hypovitaminosis D, along with the anti-inflammatory and insulin-sensitizing properties of vitamin D, have been
largely described, but vitamin D effects on hepatic fat content have never been tested in a randomized controlled
trial. We assessed the efficacy and safety of 24-week oral high-dose vitamin D supplementation in T2D patients
with NAFLD.
Methods: This randomized, double-blind, placebo-controlled trial was carried out at the Diabetes Centre of
Sapienza University, Rome, Italy, to assess oral treatment with cholecalciferol (2000 IU/day) or placebo in T2D
patients with NAFLD. The primary endpoint was reduction of hepatic fat fraction (HFF) measured by magnetic
resonance; as hepatic outcomes, we also investigated changes in serum transaminases, CK18-M30, N-terminal
Procollagen III Propeptide (P3NP) levels, and Fatty Liver Index (FLI). Secondary endpoints were improvement in
metabolic (fasting glycaemia, HbA1c, lipids, HOMA-IR, HOMA-β, ADIPO-IR, body fat distribution) and cardiovascular
(ankle-brachial index, intima-media thickness, flow-mediated dilatation) parameters from baseline to end of treatment.
Results: Sixty-five patients were randomized, 26 (cholecalciferol) and 29 (placebo) subjects completed the study.
25(OH) vitamin D significantly increased in the active treated group (48.15 ± 23.7 to 89.80 ± 23.6 nmol/L, P < 0.001);
however, no group differences were found in HFF, transaminases, CK18-M30, P3NP levels or FLI after 24 weeks. Vitamin
D neither changed the metabolic profile nor the cardiovascular parameters.
Conclusions: Oral high-dose vitamin D supplementation over 24 weeks did not improve hepatic steatosis or
metabolic/cardiovascular parameters in T2D patients with NAFLD. Studies with a longer intervention period are
warranted for exploring the effect of long time exposure to vitamin D
Glycated hemoglobin for the diagnosis of diabetes and prediabetes: Diagnostic impact on obese and lean subjects, and phenotypic characterization
Aims/Introduction
Measurement of glycated hemoglobin (HbA1c) has been recommended for the diagnosis of diabetes and prediabetes. However, epidemiological studies have shown significant discordance between HbA1c and glucose-based tests. Of the factors that could influence agreement between HbA1c and the oral glucose tolerance test (OGTT), bodyweight has not been fully evaluated. The aims of the present study were to evaluate the impact of HbA1c criteria to diagnose diabetes and prediabetes compared with OGTT, and to examine HbA1c in relation to body mass index.
Materials and Methods
Two cohorts were studied, one from an obesity clinic (n = 592) and one from subjects undergoing screening for diabetes (n = 462). All underwent OGTT and HbA1c measurement.
Results
In the obese cohort, HbA1c ≥6.5% (≥48 mmol/mol) showed a sensitivity of 69.3% for diabetes, whereas HbA1c 5.7–6.4% (39–46 mmol/mol) did not identify prediabetes well (sensitivity 39.1%). In the diabetes screening cohort, HbA1c h
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