The protective role of the Mediterranean diet on the prevalence of metabolic syndrome in a population of Greek obese subjects.

BACKGROUND: Obesity is a rapidly expanding epidemic in Western societies, with rates of more than 30% across Europe, and it is associated with an increased risk of metabolic disturbances. Previous reports have documented an association of reduced physical activity and abstinence from the traditional Mediterranean diet (MD) with increased mortality rate and prevalence of obesity in a population of Greek subjects. OBJECTIVE: The aim of the present study was to evaluate and analyze the dietary habits in a population of Greek overweight and obese subjects and to investigate the potential associations between those patterns and the prevalence of metabolic syndrome components. METHODS: The study recruited 226 consecutive adult (30 men, 169 women) overweight or obese (body mass index >25 kg/m(2)) individuals attending the Metabolic Diseases Unit. Medical history, dietary history, and anthropometric parameters were recorded during the first visit. Fasting blood samples were collected for biochemistry assaying. RESULTS: According to the nutrient intake history and Mediterranean Diet Scale (MDS), participants were divided into 3 groups: those adhering to the MD and those not following the MD, who were further subdivided into the high-carbohydrate (HC) and high-fat (HF) diet groups according to the source of maximum energy intake. Adherence to the MD was associated with a lower prevalence of metabolic syndrome (27.3%, 69.2%, and 60.4% in MD, HC, and HF respectively, p = 0.006), lower low-density lipoprotein cholesterol (p = 0.009, MD vs. HF), and lower postchallenge glucose values (p = 0.028, MD vs. HF). CONCLUSIONS: Adherence to the MD seems to be declining among Greek overweight and obese subjects, a phenomenon that is associated with an increase in the prevalence of the metabolic syndrome.

Signaling components involved in leptin-induced amplification of the atherosclerosis-related properties of human monocytes.

BACKGROUND/AIMS: Leptin, a 16-kDa cytokine that is released mainly by the adipose tissue, is known to affect a wide assortment of processes, ranging from energy homeostasis to angiogenesis and the immune response. In the present study, the effect of leptin on atherosclerosis-related properties of human monocytes was investigated. methods: Monocytes were isolated from whole blood obtained from healthy donors who had normal body mass index values. Pharmacological inhibition of specific signaling proteins was implemented. Fluorescence spectrometry and immunofluorescence techniques, as well as ELISA methods, were utilized. Leptin dose response curves were determined for each type of experiment. RESULTS: Leptin (160 ng/ml) was found to augment monocyte adhesion to laminin-1 and its migration through this glycoprotein, which is one of the main components of the extracellular matrix. Additionally, leptin increased CD36-receptor surface expression, as well as moderately oxidized low-density lipoprotein (oxLDL(3)) uptake levels. CONCLUSION: Leptin amplifies the pro-atheromatic properties of human monocytes through a complex signaling net which involves the Na(+)/H(+) exchanger isoform-1, the actin cytoskeleton, phosphoinositide 3-kinase, certain conventional isoforms of protein kinase C and NADPH oxidase.

Monocyte attachment and migration through collagen IV in diabetes mellitus.

The interactions between monocytes and extracellular matrix proteins have been implicated in atherosclerosis pathophysiology. In the present study we evaluated monocyte attachment and migration through oxidized and non-oxidized collagen IV. Monocyte attachment was tested on microwells coated with either native or oxidized collagen IV. Monocyte migration through collagen IV was examined on transwells. Monocytes derived from patients with diabetes mellitus showed an increased ability to attach and migrate through collagen IV as compared to those derived from healthy volunteers. Moreover, control monocytes attached to oxidized collagen at a higher degree, while they migrated through oxidized collagen at a lower degree, as compared to the native protein. Our results also showed the involvement of the alpha2 integrin subunit in the above phenomena suggesting a modified interaction between monocytes and collagen IV in diabetes mellitus.

NHE-1: a molecular target for signalling and cell matrix interactions.

The activation of sodium/hydrogen exchanger (NHE) is associated with a variety of cell functions like cell adhesion, migration, proliferation, and apoptosis. Since its discovery, 9 NHE isoforms have been identified, but the most widely spread and the most important for the cellular functions is NHE-1. This ubiquitously expressed sodium/hydrogen exchanger (NHE-1) plays a central housekeeping role in all cells regulating cell volume and internal pH (pHi). At physiological pHi, NHE-1 is essentially inactive but it is extremely sensitive to pHi changes, being rapidly activated by small intracellular hydrogen concentration increases. NHE-1 activity can be stimulated via a series of cell surface receptors, including tyrosine kinase, G-protein-coupled, and integrin receptors. These signals converge, regulating the affinity of the internal hydrogen-binding site. NHE-1 also is a plasma membrane-anchoring protein for the cytoskeleton. Cytoskeleton anchoring of NHE-1 is important for cell adhesion to extracellular matrix proteins and cell migration. Moreover, NHE-1 plays the role of a "scaffold" for the building of various intracellular signaling molecule clusters.

Prooxidant-antioxidant balance as a new risk factor in patients with angiographically defined coronary artery disease.

OBJECTIVES: Determination of the prooxidant-antioxidant balance (PAB) in patients with angiographically defined coronary artery disease (CAD+) by a modified PAB assay and presentation of PAB value as a novel cardiovascular risk factor. DESIGN AND METHODS: For 61 patients with CAD+ and 63 healthy volunteers, the PAB were measured and its correlation was determined with anthropological and clinical parameters. RESULTS: A significant increase of the PAB value was observed in patients in comparison to control group. A correlation, which is not quite significant, was noted between angiographic finding (number of diseased vessel) and the PAB values in patients. A significant positive correlation was established between the PAB value and systolic blood pressure, diastolic blood pressure, smoking, fasting blood sugar and serum urea concentration; and a significant negative correlation was established between PAB value and serum creatinine and bilirubin. CONCLUSIONS: This study shows that the PAB value may be considered as a cardiovascular risk factor. Further clinical research is needed to substantiate the potency of the PAB value as a cardiovascular risk factor.

Eosinophilic pneumonia associated with heroin inhalation: a case report.

Drugs are known to be a cause of pulmonary eosinophilia and several case reports of acute eosinophilic pneumonia associated with the use of cocaine have been reported. The changing pattern of heroin use, with a shift from intravenous use to smoking/inhalation of the substance, may lead to increased prevalence of heroin-induced pulmonary eosinophilia. We report on a case of a patient who had been inhaling heroin for about ten years. He presented with fever, cough, dyspnea and pleuritic chest pain. Chest radiograph showed unilateral pleural effusion with segmental atelectasis. Examination of pleuritic fluid aspirate and bronchoalveolar lavage fluid revealed significant eosinophilia. He was diagnosed with acute eosinophilic pneumonia. Rapid remission was achieved after heroin abstinence and initiation of corticosteroid treatment.

Effect of endothelin on sodium/hydrogen exchanger activity of human monocytes and atherosclerosis-related functions.

The objective of this article is to investigate the influence of endothelin-1 (ET-1) on human monocyte Na(+)/H(+) exchanger (NHE) activity and on the atherosclerosis-related monocyte functions. ET-1 caused an increase in pHi and in (22)Na influx of monocytes. A reversal of ET-1 effect on pHi was observed in the presence of the NHE1 inhibitor, cariporide. In addition, the activation of NHE1 by ET-1 was mediated via protein kinase C (PKC), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and NADPH oxidase. Also, a link between ET-1 and nitric oxide (NO) was observed. Furthermore, after ET-1 treatment, an increase of the adhesive capacity, the migration ability on laminin and CD36 expression of monocytes, was observed; using cariporide this increase was abolished. Our results showed that ET-1 induces a signaling pathway with the involvement of PKC, MAPK, PI3K, and NADPH oxidase where NHE1 plays a key role. ET-1 also plays a significant role in atherosclerosis-related functions of human monocytes, via NHE1 activation.

A novel assay for the evaluation of the prooxidant-antioxidant balance, before and after antioxidant vitamin administration in type II diabetes patients.

OBJECTIVES: The application of a novel assay for the direct measurement of prooxidant-antioxidant balance (PAB) in type II diabetes and the evaluation of antioxidant therapy. DESIGN AND METHODS: The assay is based on 3,3',5,5'-tetramethylbenzidine and its cation, used as a redox indicator participating in two simultaneous reactions. PAB was determined in the sera of healthy volunteers and type II diabetes patients. The results were compared with clinical and biological parameters, protein oxidation markers, as well as the results of antioxidant and prooxidant assays. PAB, after administration of vitamins C and E for 1 day, 1 month and 2 months was also determined. RESULTS: Increased PAB was found in the patients' group and correlated with parameters involved in diabetic complications, protein oxidation markers, antioxidant and prooxidant assays. One day after vitamin administration, a significant shift of PAB towards antioxidants was observed. PAB remained unchanged after 1 month and changed marginally in favor of prooxidants in the second month of the therapy. CONCLUSIONS: These results indicate that the measurement of PAB may be useful to identify and follow-up patients who need antioxidant therapy.

Enhanced laminin carbonylation by monocytes in diabetes mellitus.

OBJECTIVES: Monocyte-extracellular matrix interactions have been implicated in atherosclerosis pathophysiology. In the present study we evaluated the oxidation of laminin by monocytes derived from either diabetic patients or healthy volunteers. Moreover, reactive oxygen species production was measured. Monocyte attachment and migration through oxidized and non-oxidized laminin were also studied. DESIGN AND METHODS: Laminin oxidation was tested by a sensitive ELISA assay in isolated monocytes. ROS production was measured with fluorescent indicators. 35S-methionine was used for evaluating monocyte attachment. Monocyte migration through laminin was examined on transwells. RESULTS: Monocytes derived from patients with diabetes mellitus showed an increased ability to carbonylate and attach to laminin. Diabetic monocytes produced increased levels of ROS as compared to controls. Our results showed the involvement of the alpha2 integrin subunit in monocyte attachment to both native and oxidized laminin in control and diabetic monocytes. CONCLUSIONS: The results indicate a modified interaction between monocytes and laminin in diabetes.

Insulin sensitivity assessment with euglycemic insulin clamp in adult beta-thalassaemia major patients.

OBJECTIVE: To assess insulin sensitivity in young adult normoglycemic beta-thalassaemia major patients. METHODS: We measured insulin sensitivity with the euglycemic insulin clamp in 10 young adult (mean age 24.85 +/- 2.45 yrs) normoglycemic beta-thalassaemia major patients and 10 sex- & age-matched controls. Liver iron accumulation was assessed by magnetic resonance imaging (MRI). RESULTS: Glucose infusion rate (M) required to maintain euglycemia was significantly reduced in thalassaemic patients compared to controls (261.5 +/- 63.5 mg/m2 x min vs. 355.6 +/- 35.3 mg/m2 x min, P = 0.008). Consequently, significantly reduced in the thalassaemic group were also tissue sensitivity to insulin (M/I(s-s)) and glucose metabolic clearance rate (M/G(s-s)). There was significant negative correlation between ferritin levels and glucose infusion rate (r = -0.918 P = 0.004). No significant correlations were observed between age, body mass index, daily transfusional iron accumulation, liver iron content and any of the euglycemic clamp parameters. Fasting insulin levels were significantly increased in patients with beta-thalassaemia major compared to controls (P = 0.01), and had significant negative correlation to MRI-derived liver iron content (r = -0.733, P = 0.03). CONCLUSIONS: Our data indicate that reduced insulin sensitivity resulting in hyperinsulinaemia precedes the manifestation of glucose intolerance in patients with beta-thalassaemia major. Insulin resistance seems to correlate with increased serum ferritin levels.

High sensitivity enzyme-linked immunosorbent assay (ELISA) method for measuring protein carbonyl in samples with low amounts of protein.

The oxidative modification of proteins has been shown to play a major role in a number of pathological processes. One such modification is the addition of the carbonyl groups to the amino acid residue in proteins. For the measurement of the carbonyl groups in low concentration protein samples, we have modified the ELISA (enzyme-linked immunosorbent assay) method that was developed by Buss et al. [Buss, I. H; Chan, T. P.; Sluis, K. B.; Domigan, N. M.; Winterbourn, C. C. Protein carbonyl measurement by a sensitive ELISA method. Free Radic. Biol. Med.23:361-366; 1997 ]. In the modified method, protein samples diluted in phosphate-buffered saline were adsorbed to wells of an ELISA plate and then reacted with dinitrophenylhydrazine (DNPH). The protein-conjugated DNPH was probed by a commercial anti-DNPH antibody, and then a second antibody conjugated with horseradish peroxidase was added for quantification. The method was calibrated using oxidized albumin, and required only 5 mug protein. This obviated the need to concentrate protein in experimental and clinical samples with low amounts of protein. In addition the effect of TCA on carbonyl measurement is eliminated. The standard curve was linear in the range of 0-3.36 nmol carbonyls/mg protein, which is the range within which clinical samples fell. The results correlated well with the colorimetric carbonyl assay. The method was used to analyze the amount of protein carbonyl in aqueous humor and diluted plasma samples.

Dipeptidyl peptidase-4 inhibitors for treatment of type 2 diabetes mellitus in the clinical setting: systematic review and meta-analysis.

OBJECTIVE: To assess the efficacy and safety of dipeptidyl peptidase-4 (DPP-4) inhibitors compared with metformin as monotherapy, or with other commonly used hypoglycaemic drugs combined with metformin, in adults with type 2 diabetes mellitus. DESIGN: Systematic review and meta-analysis of randomised controlled trials. DATA SOURCES: Medline, Embase, the Cochrane Library, conference proceedings, trial registers, and drug manufacturers' websites. ELIGIBILITY CRITERIA: Randomised controlled trials of adults with type 2 diabetes mellitus that compared a DPP-4 with metformin as monotherapy or with a sulfonylurea, pioglitazone, a glucagon-like peptide-1 (GLP-1) agonist, or basal insulin combined with metformin on the change from baseline in glycated haemoglobin (HbA(1c)). DATA EXTRACTION: The primary outcome was the change in HbA(1c). Secondary outcomes included the proportion of patients achieving the goal of HbA(1c) <7%, the change in body weight, discontinuation rate because of any adverse event, occurrence of any serious adverse event, all cause mortality, and incidence of hypoglycaemia, nasopharyngitis, urinary tract infection, upper respiratory infection, nausea, vomiting, and diarrhoea. RESULTS: 27 reports of 19 studies including 7136 patients randomised to a DPP-4 inhibitor and 6745 patients randomised to another hypoglycaemic drug were eligible for the systematic review and meta-analysis. Overall risk of bias for the primary outcome was low in three reports, unclear in nine, and high in 14. Compared with metformin as monotherapy, DPP-4 inhibitors were associated with a smaller decline in HbA(1c) (weighted mean difference 0.20, 95% confidence interval 0.08 to 0.32) and in body weight (1.5, 0.9 to 2.11). As a second line treatment, DPP-4 inhibitors were inferior to GLP-1 agonists (0.49, 0.31 to 0.67) and similar to pioglitazone (0.09, -0.07 to 0.24) in reducing HbA(1c) and had no advantage over sulfonylureas in the attainment of the HbA(1c) goal (risk ratio in favour of sulfonylureas 1.06, 0.98 to 1.14). DPP-4 inhibitors had a favourable weight profile compared with sulfonylureas (weighted mean difference -1.92, -2.34 to -1.49) or pioglitazone (-2.96, -4.13 to -1.78), but not compared with GLP-1 agonists (1.56, 0.94 to 2.18). Only a minimal number of hypoglycaemias were observed in any treatment arm in trials comparing a DPP-4 inhibitor with metformin as monotherapy or with pioglitazone or a GLP-1 agonist as second line treatment. In most trials comparing a DPP-4 inhibitor with sulfonylureas combined with metformin, the risk for hypoglycaemia was higher in the group treated with a sulfonylurea. Incidence of any serious adverse event was lower with DPP-4 inhibitors than with pioglitazone. Incidence of nausea, diarrhoea, and vomiting was higher in patients receiving metformin or a GLP-1 agonist than in those receiving a DPP-4 inhibitor. Risk for nasopharyngitis, upper respiratory tract infection, or urinary tract infection did not differ between DPP-4 inhibitors and any of the active comparators. CONCLUSION: In patients with type 2 diabetes who do not achieve the glycaemic targets with metformin alone, DPP-4 inhibitors can lower HbA(1c), in a similar way to sulfonylureas or pioglitazone, with neutral effects on body weight. Increased unit cost, which largely exceeds that of the older drugs, and uncertainty about their long term safety, however, should also be considered.

Loss-of-function mutations in MC4R are very rare in the Greek severely obese adult population.

Melanocortin-4 receptor (MC4R) loss-of-function mutations are the commonest genetic cause of human monogenic obesity, so far. The contribution of MC4R coding mutations to severe obesity in the high-obesity prone Greek population has not been investigated to date. We determined the MC4R coding sequence of 510 obese and 469 lean control subjects of Greek origin, and we estimated the prevalence and the penetrance on obesity of MC4R loss-of-function mutations. The functional impact of novel nonsynonymous variants detected was investigated in vitro. We found two novel synonymous mutations (L23L and I102I), four nonsynonymous mutations (T112M, S127L, N274S, and S295L), and two polymorphisms (V103I and I251L) previously described in literature. We also detected a novel mutation (L207V) in a severely obese 69-year-old female patient, although the mutation did not cosegregate with obesity in the corresponding pedigree and had no functional consequences on MC4R protein function. Loss-of-function mutations represented 75% of all nonsynonymous rare mutations identified among lean carriers and only 25% among obese subjects (P = 0.0001). The prevalence of loss-of-function mutations was lower in the obese group than in lean control subjects (0.20 vs. 0.64%) but this difference was not significant. Therefore, the estimated penetrance of deleterious MC4R mutations was very low (6.3%) in heterozygous Greek carriers of MC4R loss-of-function mutations. Our data suggest that MC4R loss-of-function mutations are rare in the Greek population. MC4R genetic deficiency is unlikely to explain the high propensity to develop severe obesity in this specific population.

Common variants in FTO, MC4R, TMEM18, PRL, AIF1, and PCSK1 show evidence of association with adult obesity in the Greek population.

Twenty-four single-nucleotide polymorphisms (SNPs) have been reproducibly associated with obesity. We performed a follow-up study for obesity in the Greek adult population. A total of 510 obese and 469 lean adults were genotyped for 24 SNPs. We tested the association with obesity status using logistic regression and we evaluated the combined genetic risk of 24 SNPs by calculating the area under the receiver-operating characteristic (ROC) curves. We nominally replicated the association with obesity (BMI ≥30 kg/m(2)) of six SNPs in or near the FTO, MC4R, TMEM18, PRL, AIF1, and PCSK1 loci (1.28 ≤ odds ratio (OR) ≤ 1.35; 0.004 ≤ P ≤ 0.043). The discrimination ability for obesity was slightly stronger (P = 9.59 × 10(-6)) when the genetic information of the 24 SNPs was added to nongenetic risk factors (area under the curve (AUC) = 0.722) in comparison with nongenetic factors analyzed alone (AUC = 0.685). Our data suggest that SNPs in or near the FTO, MC4R, TMEM18, PRL, AIF1, and PCSK1 loci contribute to obesity risk in the Greek population.

NHE-1 and ß1 integrin dependent monocyte adhesion and migration after glucose, insulin or PPARγ stimulation.

In the present study the effect of high glucose concentrations, insulin, PPARγ activators (rosiglitazone) and NHE-1 inhibitors (cariporide) in atherosclerosis-related functions of human monocytes was investigated. Monocyte adhesion to laminin-1, collagen type IV and endothelial cells, as well as monocyte migration through the same substrates were studied. Incubation of the monocyte suspension with high glucose concentrations, insulin and rosiglitazone induced all the studied atherosclerosis-related functions of the monocytes. In all these functions the addition of cariporide counteracted the activity of glucose, insulin and rosiglitazone. The use of antigen for ß1 integrin also counteracted the activity of the above in monocyte adhesion in all three substrates. The data of the present study suggests that PPARγ activation in monocytes induces atherosclerosis, and that NHE-1 and ß1 integrin play an important role in the beginning of atherosclerosis.

Effect of glucose and insulin on oxidized low-density lipoprotein phagocytosis by human monocytes: a pilot study.

We assessed the effect of glucose and insulin on human monocytes. Monocytes were isolated from 16 healthy obese and 10 lean healthy participants. Insulin sensitivity was assessed by euglycemic hyperinsulinemic clamp. Obese participants were subdivided into 2 subgroups: insulin sensitive (IS) and insulin resistant (IR). Monocyte oxidized low-density lipoprotein (oxLDL) phagocytosis was assessed pre and poststimulation in vitro with glucose or insulin. Experiments were repeated after incubation with a Na(+)/H(+) exchanger-1 inhibitor ([NHE-1]; cariporide) or rosiglitazone. Glucose increased oxLDL phagocytosis in all groups studied (at 1 or 3 hours incubation; P = .037-.002). Insulin increased oxLDL phagocytosis in all groups studied after 1-hour incubation (P = .027-.015) but not at 3 hours. Incubation with cariporide attenuated oxLDL phagocytosis except in the obese IS group. Rosiglitazone eliminated glucose- and insulin-induced increase in oxLDL phagocytosis in all studied groups. Glucose and insulin induce oxLDL phagocytosis.

Effect of epinephrine and insulin resistance on human monocytes obtained from lean and obese healthy participants: a pilot study.

We assessed the effect of epinephrine on human monocytes. Monocytes were isolated from 16 healthy obese and 10 lean healthy subjects. Insulin sensitivity was assessed by euglycemic hyperinsulinemic clamp. Obese subjects were subdivided into 2 sub-groups, insulin sensitive (IS) and insulin resistant (IR). Monocyte properties [attachment to laminin 1, migration through laminin 1, oxidized-low density lipoprotein (oxLDL) phagocytosis] were assessed pre- and post-stimulation in vitro with epinephrine. Experiments were repeated after incubation with a Na(+)/H( +) exchanger-1 inhibitor (NHE-1) (cariporide). Epinephrine increased monocyte attachment to laminin in lean and obese IR subjects through involvement of NHE-1, PKC, NO synthase, NADPH oxidase and actin polymerization. In contrast, epinephrine did not affect monocyte migration. Epinephrine increased oxLDL phagocytosis in all groups studied. Incubation with cariporide attenuated oxLDL phagocytosis. Epinephrine induces monocyte dysfunction which may be atherogenic.

Accuracy of the Neuropad test for the diagnosis of distal symmetric polyneuropathy in type 2 diabetes.

OBJECTIVE: To estimate the accuracy of Neuropad for the diagnosis and staging of distal symmetric polyneuropathy (DPN) across different stages of neuropathy, using multiple-level likelihood ratios (LRs) to interpret the time necessary to complete the color change of the test. RESEARCH DESIGN AND METHODS: We conducted a cross-sectional, cohort-type diagnostic accuracy study in 251 consecutive adult type 2 diabetic patients with no peripheral arterial disease or other potential causes of neuropathy, who were recruited between January 2005 and December 2008 from the diabetes outpatient clinics in Alexandroupolis Hospital, Greece. Patients were tested for DPN by means of the neuropathy disability score (NDS) and Neuropad. Multiple-level LRs for time to complete color change were calculated across different stages of neuropathy. RESULTS: The areas under the curve for the diagnosis of any (NDS of ≥3), at least moderate (NDS of ≥6), or severe (NDS of ≥9) DPN were 0.91, 0.96, and 0.97, respectively. The calculation of multiple-level LRs showed that time to complete color change <360 s suggested the absence of neuropathy. Values between 360 and 1,000 s were indicative of mild neuropathy. Finally, values between 1,000 and 1,200 or >1,200 s were strongly suggestive of moderate or severe DPN, respectively. CONCLUSIONS: Neuropad could be used as a triage test for the diagnosis and staging of DPN in patients with type 2 diabetes, prompting referral to specialized care setting.