Obese individuals with more components of the metabolic syndrome and/or prediabetes demonstrate decreased activation of reward-related brain centers in response to food cues in both the fed and fasting states: a preliminary fMRI study.

It remains unknown whether obese individuals with more components of the metabolic syndrome and/or prediabetes demonstrate altered activation of brain centers in response to food cues. We examined obese individuals with prediabetes (n=26) vs obese individuals without prediabetes (n=11) using fMRI. We also performed regression analyses on the basis of the number of MetS components per subject. Obese individuals with prediabetes have decreased activation of the reward-related putamen in the fasting state and decreased activation of the salience- and reward-related insula after eating. Obese individuals with more components of MetS demonstrate decreased activation of the putamen while fasting. All these activations remain significant when corrected for BMI, waist circumference (WC), HbA1c and gender. Decreased activation in the reward-related central nervous system areas among the obese is more pronounced in subjects with prediabetes and MetS. Prospective studies are needed to quantify their contributions to the development of prediabetes/MetS and to study whether they may predispose to the exacerbation of obesity and the development of comorbidities over time.

Leptin administration in physiological or pharmacological doses does not alter circulating irisin levels in humans.

Leptin is an adipokine causing browning of adipose tissue, and it thus increases energy expenditure. The same is true for irisin. We studied whether exogenously administered metreleptin affects serum irisin concentrations in humans, which would suggest a direct interplay between leptin and irisin. We performed two studies: a dose-escalating 1-day-long study and a randomized placebo-controlled study. Study 1: 15 healthy, normal-weight and/or obese male and female individuals participated in three 1-day-long trials of metreleptin administration in the fed state. Metreleptin was administered once at physiological and pharmacological (0.01, 0.1 and 0.3 mg per kg body weight) doses. Study 2: 18 apparently healthy hypoleptinemic young women with hypoleptinemia and secondary amenorrhea took part in this study. Subjects received either metreleptin in replacement doses (0.08 and/or 0.12 mg kg(-1)) or placebo for 16 weeks. Blood samples were analyzed for leptin and irisin. We found no effect of metreleptin administration on irisin levels of subjects studied at either the fasting or the fed state either in the short or the long term. We provide evidence that leptin is not altering circulating irisin levels in humans.

Lack of Day/Night variation in fibroblast growth factor 21 levels in young healthy men.

BACKGROUND: Fibroblast growth factor (FGF) 21 is an endocrine factor with an emerging role as a metabolic regulator. We previously reported the presence of a significant day/night variation of FGF-21 in energy-replete, healthy female subjects. However the day/night patterns of secretion in male subjects remain to be fully elucidated. To elucidate day/night pattern of FGF-21 levels in male subjects in the energy-replete state, its relationship to FFA and to investigate whether a sexual dimorphism exists in FGF-21 physiology. METHODS: Eight healthy lean male subjects were studied for up to 5 days while on an isocaloric diet. Blood samples were obtained for measurement of FGF-21 and free fatty acids (FFA) hourly from 0800 AM on day 4 till 0800AM on day 5. RESULTS: FGF-21 did not exhibit any statistically significant day/night variation pattern of circulating FGF-21 levels during the isocaloric fed state in male subjects. FGF-21 levels in male subjects are closely cross-correlated with FFA levels, similar to female subjects. CONCLUSIONS: A sexual dimorphism exists in FGF-21 physiology; that as opposed to female subjects, no significant day/night variation exists in FGF-21 rhythm in male subjects in the energy-replete state. Circulating pattern of FGF-21, similar to the female subjects, was highly cross-correlated to the FFA levels in the male subjects, signifying that the sexual dimorphism in FGF-21 physiology may be related to the differing lipid metabolism in both the genders.

Lack of mature lymphocytes results in obese but metabolically healthy mice when fed a high-fat diet.

BACKGROUND/OBJECTIVES: Obesity is characterized by chronic inflammation and immune dysregulation, as well as insulin resistance, but the link between obesity and adaptive immunity remains to be fully studied. METHODS: To elucidate the role of adaptive immunity on body composition, glucose homeostasis and inflammation, recombination-activating gene 1 knockout (Rag1-/-) mice, without mature T-lymphocytes or B-lymphocytes, were maintained on a low- or high-fat diet (LFD and HFD, respectively) for 11 weeks. RESULTS: Rag1-/- mice fed HFD gained significantly more weight and had increased body fat compared with wild type. Downregulation of energy expenditure as well as brown fat uncoupling protein UCP-1 and UCP-3 gene expression were noticed in HFD-fed Rag1-/- mice compared with LFD. HFD mice had significantly decreased energy intake compared with LFD mice, consistent with decreased agouti-related protein and increased pro-opiomelanocortin gene expression levels in the hypothalamus. Moreover, compared with wild type, Rag1-/- mice had lower interleukin (IL)-4 levels, a cytokine recently found to induce browning in white adipocytes, and higher IL-12 levels in HFD-fed Rag1-/- mice. Despite that HFD Rag1-/- mice were more obese, they had similar glucose, insulin and adiponectin levels, while leptin was marginally increased. CONCLUSIONS: Mice with deficiency in adaptive immunity are obese, partly owing to decreased energy expenditure, but are metabolically normal, suggesting that mature lymphocytes have necessary roles in the development of obesity-related metabolic dysregulation.

Circulating irisin levels and coronary heart disease: association with future acute coronary syndrome and major adverse cardiovascular events.

INTRODUCTION: Irisin is a newly discovered myokine, associated with 'browning' of the white adipose tissue, obesity, insulin resistance and metabolic syndrome. The purpose of this study is to evaluate circulating irisin as a predictor of acute coronary syndromes (ACSs) and major adverse cardiovascular events (MACE). METHODS: Sub-study 1: a case-control study, nested within the Veteran's Affairs Normative Ageing Study, evaluating circulating irisin levels in 88 ACS cases and 158 age- and sampling year-matched controls, as a predictor of ACS. Sub-study 2: a prospective cohort study, where 103 participants with established coronary artery disease were stratified by circulating irisin levels at the time they received percutaneous coronary interventions (PCIs) and were followed for the development of MACE. RESULTS: Study 1: there was no association between irisin levels and ACS in otherwise healthy individuals (odds ratio: 1.00 95% confidence interval: (0.99-1.00)). Study 2: the incidence of MACE was significantly lower in the first irisin tertile compared with the second and third (incidence rate 0 vs 0.92 (0.51-1.61) vs 0.57 (0.28-1.14) events per 1000 person-days; P < 0.01). This was primarily driven by the lower incidence of unstable angina (incidence rate 0 vs 0.61 (0.31-1.22) vs 0.43 (0.19-0.96) per 1000 person-days; P = 0.01). CONCLUSION: This is the first study to date that demonstrates that, although circulating irisin levels do not predict the development of ACS in healthy individuals, increased irisin levels are associated with the development of MACE in patients with established coronary artery disease after PCI.

Posttraumatic stress disorder, alone or additively with early life adversity, is associated with obesity and cardiometabolic risk.

BACKGROUND AND AIMS: There is some evidence that posttraumatic stress disorder (PTSD) and early life adversity may influence metabolic outcomes such as obesity, diabetes, and cardiovascular disease. However, whether and how these interact is not clear. METHODS: We analyzed data from a cross-sectional and longitudinal study to determine how PTSD severity influences obesity, insulin sensitivity, and key measures and biomarkers of cardiovascular risk. We then looked at how PTSD and early life adversity may interact to impact these same outcomes. RESULTS: PTSD severity is associated with increasing risk of obesity, diabetes, and cardiovascular disease, with higher symptoms correlating with higher values of BMI, leptin, fibrinogen, and blood pressure, and lower values of insulin sensitivity. PTSD and early life adversity have an additive effect on these metabolic outcomes. The longitudinal study confirmed findings from the cross sectional study and showed that fat mass, leptin, CRP, sICAM-1, and sTNFRII were significantly increased with higher PTSD severity during a 2.5 year follow-up period. CONCLUSIONS: Individuals with early life adversity and PTSD are at high risk and should be monitored carefully for obesity, insulin resistance, and cardiometabolic risk.

Irisin stimulates muscle growth-related genes and regulates adipocyte differentiation and metabolism in humans.

BACKGROUND: Irisin is a recently identified exercise-induced myokine suggested to induce browning of white adipocytes. Deficiency of myostatin, and thus stimulation of muscle growth, has also been reported to induce irisin and its precursor FNDC5 expression in muscle and drive the browning of white adipocytes in mice, implying that irisin may be related to muscle growth in addition to its beneficial effects in adipocytes. In humans, the effect of irisin in muscle hypertrophy as well as adipocyte metabolism has not been fully investigated. METHODS: Primary cultured human myocytes/adipocytes and 3T3-L1 cells were used to examine irisin-regulated gene/protein expression. Lipid accumulation, ATP content, glycolysis, lipolysis and metabolite profile were measured in control and irisin-treated (10 and 50 nM) adipocytes. RESULTS: In human myocytes, FNDC5 mRNA and irisin secretion were increased during myogenic differentiation, along with PGC1α and myogenin expression. Irisin treatment significantly increased insulin-like growth factor 1 and decreased myostatin gene expression through ERK pathway. PGC1α4, a newly discovered PGC1α isoform specifically related to muscle hypertrophy, was also upregulated. In human adipocytes, irisin induced uncoupling protein 1 and consequently increased adipocyte energy expenditure, expression of metabolic enzymes and metabolite intermediates, resulting in inhibition of lipid accumulation. Irisin and FNDC5 treatment also reduced preadipocyte differentiation, suggesting an additional mechanism in suppressing fat mass. CONCLUSIONS: These results suggest that irisin/FNDC5 has a pleiotropic role in muscle and improvement of adipocyte metabolism in humans.

Levels of circulating selenoprotein P, fibroblast growth factor (FGF) 21 and FGF23 in relation to the metabolic syndrome in young children.

BACKGROUND/OBJECTIVES: Circulating selenoprotein P (SeP), fibroblast growth factor (FGF) 21 and FGF23 have been associated with metabolic syndrome (MetS) in adults but not in children. We sought to evaluate the association among SeP, FGF21, FGF23 and MetS in young children. SUBJECTS/METHODS: A cross-sectional study conducted during a school health examination on 210 children aged 9 years. We measured serum SeP, FGF21 and FGF23 levels, and assessed anthropometric and cardiometabolic variables. MetS was defined as the presence of ⩾3 of the following five criteria: high blood pressure, low high-density lipoprotein cholesterol (HDL-C), high triglyceride, high fasting glucose and abdominal obesity. RESULTS: SeP was correlated positively with HDL-C and negatively with body mass index, waist circumference (WC), blood pressure, transaminases, triglyceride and homeostasis model assessment of insulin resistance (HOMA-IR). FGF21 was directly correlated with WC, triglyceride and HOMA-IR, and FGF23 was inversely correlated with fasting glucose and alanine aminotransferase. Children with MetS had lower SeP and FGF23 levels and higher HOMA-IR than children without MetS. The highest tertile of SeP had decreased odds for MetS (odds ratio 0.05, 95% confidence interval (CI) 0.00-0.96, P for trend=0.042), whereas FGF21 and FGF23 did not relate to the risk for MetS after controlling for confounders. CONCLUSIONS: Elevated SeP concentrations are independently associated with a reduced risk of MetS in children. The associations between FGF21, FGF23 and metabolic parameters are not of comparable significance.

Circulating irisin is associated with osteoporotic fractures in postmenopausal women with low bone mass but is not affected by either teriparatide or denosumab treatment for 3 months.

UNLABELLED: In vitro data suggest that myokine irisin may affect bone metabolism by promoting osteoblast differentiation while inhibiting osteoclast differentiation. In this study, circulating irisin levels were associated with previous osteoporotic fractures but not with bone mass and were not affected by denosumab or teriparatide treatment for 3 months. INTRODUCTION: This study aimed to evaluate predictors of circulating irisin in postmenopausal women with low bone mass and to assess a potential effect of denosumab or teriparatide treatment for 3 months. METHODS: Serum samples for irisin measurement were obtained from (a) postmenopausal women with low bone mass (lumbar spinal [LS] or femoral neck [FN] bone mineral density [BMD] T-score ≤-2.0) and their age-matched controls at baseline and 3 months after denosumab (Dmab) injection (Dmab group, n = 50; Dmab control group, n = 25) and (b) women with more severe disease (LS or FN BMD T-score ≤-2.8) and their age-matched controls at the above-mentioned time points after teriparatide (TPTD) initiation (TPTD group, n = 25; TPTD control group, n = 25). RESULTS: At baseline, irisin levels were inversely correlated with age (partial coefficient (r p ) = -0.24; p = 0.009), parathyroid hormone (PTH) (r p = -0.30; p = 0.001), and creatinine (r p = -0.23; p = 0.016) in univariate analysis, and were lower in women with (n = 26; 41.6 ± 2.7 ng/dL) than without previous osteoporotic fracture(s) (n = 99; 51.0 ± 1.6 ng/dL; p = 0.007). In multiple linear regression, previous osteoporotic fracture(s) and PTH were independently negatively associated with irisin [p = 0.04, CI -16.1 to -0.4 and p = 0.002, CI -0.3 to -0.07, respectively], but only the association with PTH remained after controlling for creatinine levels. Serum irisin levels were not different between women with or without low bone mass and were not affected by either Dmab or TPTD treatment for 3 months. CONCLUSIONS: Circulating irisin levels were associated with previous osteoporotic fracture(s); whether this association is independent or is due to confounding by lower muscle mass, potentially reflected by lower creatinine levels, remains to be fully clarified.

Amylin-induced downregulation of hippocampal neurogenesis is attenuated by leptin in a STAT3/AMPK/ERK-dependent manner in mice.

AIMS/HYPOTHESIS: Both leptin and insulin sensitivity have been linked with pathophysiological processes involving the central nervous system in general, and the hippocampus in particular, but the role of leptin in hippocampal neurogenesis has not yet been elucidated. Also, no previous studies have evaluated whether amylin or the endogenous insulin sensitiser adiponectin interact with leptin to alter hippocampal neurogenesis in mouse hippocampal neuronal (HN) cells or investigated the role of leptin, amylin or adiponectin signalling in mouse HN cells. METHODS: Hippocampal neurogenesis and leptin, amylin and adiponectin signalling were studied in vitro using mouse H19-7 HN cell lines. RESULTS: Amylin decreased cell proliferation in a dose-dependent manner. This effect was diminished by leptin administration and was dependent on signal transducer and activator of transcription 3 (STAT3)/AMP-activated protein kinase (AMPK)/extracellular signal-regulated kinase (ERK). Adiponectin effects were null. We also observed, using immunocytochemical analysis, that amylin decreased activation of microtubule-associated protein 2, a specific neurite outgrowth marker, and synapsin, a specific synaptogenesis marker. By contrast, both effects were attenuated by co-administration of leptin. Finally, we observed that these effects were blocked by pre-treatment with AG490, a STAT3 inhibitor, and STAT3 small interfering RNA administration. CONCLUSIONS/INTERPRETATION: Our data suggest that amylin in pharmacological concentrations may have a neurotoxic effect whereas leptin in physiological and pharmacological concentrations has a protective effect counteracting amylin-decreased hippocampal neurogenesis via STAT3/AMPK/ERK signalling in mouse H19-7 HN cell lines. Overall, our data support a novel role for leptin and amylin in the processes of mouse hippocampal neurogenesis and provide new insights into the mechanisms of neurogenic regulation.

Clinical and genetic predictors of weight gain in patients diagnosed with breast cancer.

BACKGROUND: Post-diagnosis weight gain in breast cancer patients has been associated with increased cancer recurrence and mortality. Our study was designed to identify risk factors for this weight gain and create a predictive model to identify a high-risk population for targeted interventions. METHODS: Chart review was conducted on 459 breast cancer patients from Northwestern Robert H. Lurie Cancer Centre to obtain weights and body mass indices (BMIs) over an 18-month period from diagnosis. We also recorded tumour characteristics, demographics, clinical factors, and treatment regimens. Blood samples were genotyped for 14 single-nucleotide polymorphisms (SNPs) in fat mass and obesity-associated protein (FTO) and adiponectin pathway genes (ADIPOQ and ADIPOR1). RESULTS: In all, 56% of patients had >0.5 kg m(-2) increase in BMI from diagnosis to 18 months, with average BMI and weight gain of 1.9 kg m(-2) and 5.1 kg, respectively. Our best predictive model was a primarily SNP-based model incorporating all 14 FTO and adiponectin pathway SNPs studied, their epistatic interactions, and age and BMI at diagnosis, with area under receiver operating characteristic curve of 0.85 for 18-month weight gain. CONCLUSION: We created a powerful risk prediction model that can identify breast cancer patients at high risk for weight gain.

Coffee consumption and risk of localized, advanced and fatal prostate cancer: a population-based prospective study.

BACKGROUND: The epidemiological evidence on possible relationships between coffee consumption and prostate cancer (PCa) risk by subtype of the disease (localized, advanced) and fatal PCa risk is limited. MATERIALS AND METHODS: A population-based cohort of 44 613 Swedish men aged 45-79 years was followed up from January 1998 through December 2010 for incidence of localized (n = 2368), advanced (n = 918) and fatal (n = 515) PCa. We assessed the associations between coffee consumption and localized, advanced and fatal PCa risk using competing-risk regressions. We examined possible effect modification by body mass index (BMI). RESULTS: For localized PCa, each one cup increase in daily coffee consumption was associated with a 3% reduced risk [sub-hazard ratio (SHR) = 0.97, 95% confidence interval (CI) = 0.95-0.99]. For advanced and fatal PCa, we found a non-significant inverse association; each one cup increase was associated with a 2% reduced risk of advanced [SHR (95% CI) = 0.98 (0.95-1.02)] and fatal PCa [SHR (95% CI) = 0.98 (0.93-1.03)]. We observed evidence of effect modification by BMI for localized PCa (Pinteraction = 0.03); the inverse association was stronger among overweight and obese men (BMI ≥ 25 kg/m(2)) compared with normal-weight men (BMI < 25 kg/m(2)). CONCLUSIONS: We observed a clear inverse association between coffee consumption and risk of localized PCa, especially among overweight and obese men.

Dropout risk and effectiveness of retention strategies in the Memory Advancement by Intranasal Insulin in Type 2 Diabetes (MemAID) Clinical Trial.

BACKGROUND: Effective recruitment and retention strategies are essential in clinical trials. METHODS: The MemAID trial consisted of 12 visits during 24 weeks of intranasal insulin or placebo treatment and 24 weeks of post-treatment follow-up in older people with and without diabetes. Enhanced retention strategies were implemented mid study to address high drop-out rate. Baseline variables used in Cox regression models to identify dropout risk factors were: demographics and social characteristics, functional measures, metabolic and cardiovascular parameters, and medications. RESULTS: 244 participants were randomized; 13 (5.3%) were discontinued due to adverse events. From the remaining 231 randomized participants, 65 (28.1%) dropped out, and 166 (71.9%) did not. The Non-retention group included 95 participants not exposed to retention strategies, of which 43 (45.2%) dropped out. The Retention group included 136 participants exposed to enhanced retention strategies, of which 22 (16.2%) dropped out. Dropout risk factors included being unmarried, a longer diabetes duration, using oral antidiabetics as compared to not using, worse executive function and chronic pain. After adjusting for exposure to retention strategies, worse baseline executive function composite score (p = 0.001) and chronic pain diagnosis (p = 0.032) were independently associated with a greater risk of dropping out. The probability of dropping out decreased with longer exposure to retention strategies and the dropout rate per month decreased from 4.1% to 1.8% (p = 0.04) on retention strategies. CONCLUSIONS: Baseline characteristics allow prediction of dropping out from a clinical trial in older participants. Retention strategies has been effective at minimizing the impact of dropout-related risk factors. TRIAL REGISTRATION: Clinical trials.gov NCT2415556 3/23/2015 (www. CLINICALTRIALS: gov).

Amylin and leptin activate overlapping signalling pathways in an additive manner in mouse GT1-7 hypothalamic, C2C12 muscle and AML12 liver cell lines.

AIMS/HYPOTHESIS: It has been suggested that amylin amplifies leptin's effects and affects energy homeostasis synergistically with leptin in animals and humans. However, no previous study has reported on amylin and leptin signalling in hypothalamic, muscle and liver cells. METHODS: Leptin and amylin signalling studies were performed in vitro in mouse GT1-7 hypothalamic, C2C12 muscle and AML12 liver cell lines. RESULTS: Treatment of mouse GT1-7 and C2C12 cells with leptin or amylin increased signal transducer and activator of transcription 3 (STAT3) phosphorylation in a dose- and time-dependent manner. In mouse AML12 cells, leptin and amylin produced a biphasic response of STAT3 activity. Importantly, all leptin and amylin signalling pathways were saturable at leptin and amylin concentrations of ∼100 and ∼50 to 100 ng/ml, respectively. Leptin and amylin in combination activated STAT3, AMP-activated protein kinase (AMPK), extracellular signal-regulated kinase (ERK) 1/2 and Akt signalling pathways in an additive manner, effects that were abolished under endoplasmic reticulum (ER) stress. Leptin, but not amylin, increased IRS-1 phosphorylation in GT1-7 hypothalamic, but not in C2C12 muscle and AML12 liver cell lines. CONCLUSIONS/INTERPRETATION: Our data suggest that leptin and amylin have overlapping and additive, but not synergistic, effects in the activation of intracellular signalling pathways. ER stress may induce leptin and amylin resistance in hypothalamic, muscle and liver cell lines. These novel insights into the mode of action of leptin and amylin suggest that these hormones may play an additive role in regulating energy homeostasis in humans.

Distinct dopaminergic personality patterns in patients with prolactinomas: a comparison with nonfunctioning pituitary adenoma patients and age- and gender-matched controls.

INTRODUCTION: Personality patterns such as extraversion and novelty seeking have been associated with an altered dopaminergic activity in healthy subjects. Patients with prolactinomas have been described as exhibiting an altered dopaminergic tone and are often treated with dopamine agonists. Little is known about the personality traits of this patient group. Hence, we aimed at examining whether patients with prolactinomas exhibit modified personality patterns compared to patients with nonfunctioning pituitary adenomas and healthy controls. SUBJECTS/METHODS: In this cross-sectional study, 86 patients with prolactinomas and 58 patients with nonfunctioning pituitary adenomas (NFPA) were compared with 172 mentally healthy age- and gender-matched controls. To assess personality traits, standardized personality questionnaires (Eysenck personality questionnaire-EPQ-RK and Tridimensional Personality Questionnaire devised by Cloninger-TPQ) were administered. RESULTS: Patients with either prolactinomas or NFPA showed a distinct personality profile compared to the normal population, characterized by increased neuroticism and they also answered in a socially desirable mode. On harm-avoidant total and subscales, they presented with a higher fear of uncertainty and also increased fatigability and asthenia. The prolactinoma patients, when contrasted with the 'clinical' control group of patients with NFPA and after post hoc tests for multiple comparisons following the Bonferroni-Holm procedure showed significantly reduced extraversion (p = 0.044) and increased shyness with strangers (p = 0.044), tending to be more neurotic and present lower scores in the novelty seeking subscale impulsiveness. CONCLUSION: This is, to our knowledge, the first study providing new evidence of an altered personality profile of prolactinoma patients which might affect the patient-doctor relationship, treatment and patient's quality of life.

Safety of Intranasal Insulin in Type 2 Diabetes on Systemic Insulin: A Double-Blinded Placebo-Controlled Sub-Study of Memaid Trial.

Aims: To determine safety of intranasal insulin (INI) in MemAID trial participants with diabetes treated with systemic insulins. Materials and Methods: This randomized, double-blinded trial consisted of 24-week INI or placebo treatment once daily and 24-week follow-up. Safety outcomes were: 1) Short-term effects on glycemic variability, hypoglycemic episodes on continuous glucose monitoring (CGM) at baseline and on-treatment. 2) Long-term effects on glucose metabolism and weight on INI/placebo treatment and post-treatment follow-up. Of 86 screened subjects, 14 were randomized, 9 (5 INI, 4 Placebo) completed CGM at baseline and on-treatment, and 5 (2 INI, 3 Placebo) completed treatment and follow-up. Results: INI was safe and was not associated with serious adverse events, hypoglycemic episodes or weight gain. INI administration did not acutely affect capillary glucose. Glycemic variability on CGM decreased with INI, compared to baseline. On INI treatment, there was a long-term trend toward lower HbA1c, plasma glucose and insulin. No interactions with subcutaneous insulins were observed. Conclusions: INI is safe in older people with diabetes treated with systemic insulins, and it is not associated with adverse events, hypoglycemia or weight gain. Future studies are needed to determine whether INI administration can reduce glycemic variability, improve insulin sensitivity and thus potentially lessen diabetes burden in this population.

Leptin administered in physiological or pharmacological doses does not regulate circulating angiogenesis factors in humans.

AIM/HYPOTHESIS: Leptin has been shown to regulate angiogenesis in animal and in vitro studies by upregulating the production of several pro-angiogenic factors, but its role in regulating angiogenesis has never been studied in humans. METHODS: The potential angiogenic effect of two doses of metreleptin (50 and 100 ng/ml) was evaluated in vitro, using a novel three-dimensional angiogenesis assay. Fifteen healthy, normoleptinaemic volunteers were administered both a physiological (0.1 mg/kg) and a pharmacological (0.3 mg/kg) single dose of metreleptin, in vivo, on two different inpatient admissions separated by 1-12 weeks. Serum was collected at 0, 6, 12 and 24 h after metreleptin administration. Twenty lean women, with leptin levels <5 ng/ml, were randomised in a 1:1 fashion to receive either physiological replacement doses of metreleptin (0.04-0.12 mg/kg q.d.) or placebo for 32 weeks. Serum was collected at 0, 8, 20 and 32 weeks after randomisation. Proteomic angiogenesis array analysis was performed to screen for angiogenic factors. Circulating concentrations of angiogenin, angiopoietin-1, platelet derived endothelial factor (PDGF)-AA, matrix metalloproteinase (MMP) 8 and 9, endothelial growth factor (EGF) and vascular EGF (VEGF) were also measured. RESULTS: Both metreleptin doses failed to induce angiogenesis in the in vitro model. Although leptin levels increased significantly in response to both short-term and long-term metreleptin administration, circulating concentrations of angiogenesis markers did not change significantly in vivo. CONCLUSIONS/INTERPRETATIONS: This is the first study that examines the effect of metreleptin administration in angiogenesis in humans. Metreleptin administration does not regulate circulating angiogenesis related factors in humans. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT00140205 and NCT00130117. FUNDING: This study was supported by National Institutes of Health-National Center for Research Resources grant M01-RR-01032 (Harvard Clinical and Translational Science Center) and grant number UL1 RR025758. Funding was also received from the National Institute of Diabetes and Digestive and Kidney Diseases grants 58785, 79929 and 81913, and AG032030.

Genetic variation within IL18 is associated with insulin levels, insulin resistance and postprandial measures.

BACKGROUND AND AIMS: IL-18 expression is up-regulated in atherosclerotic plaques, and higher levels are seen in obese and Type 2 Diabetic individuals. More recently, a possible role for IL-18 in glucose and energy homeostasis has been suggested. METHODS AND RESULTS: We investigated variation within the IL18 gene and its association with measures of obesity and the metabolic syndrome. Five IL18 tagging single nucleotide polymorphisms (rs1946519, rs2043055, rs549908, rs360729, rs3882891) were selected and genotyped in the Gene-Diet Attica Investigation on childhood obesity (GENDAI) (age range 10-14 yrs); in young European men in the second European Atherosclerosis Research offspring Study (EARSII), an offspring study (age range 18-28 yrs) and in a group of healthy women from the Greek Obese Women study (GrOW) (age range 18-74 yrs). Six common haplotypes were observed. In GrOW, Hap6 (Frequency-2.6%) was associated with higher insulin levels (p<0.0001), estimates of HOMA(-Insulin Resistance) (p<0.0001) and HOMA(-ß-cell) (p<0.0001) compared to the common haplotype Hap1 (Frequency-33.2%). In EARSII, rs2043055 was associated with peak and area under the curve triglycerides (p=0.001 and p=0.002, respectively) after an oral fat tolerance test in 'cases' but not 'controls'. None of the haplotypes were associated with measures of body fatness in any of the studies. CONCLUSION: Association of IL18 variation with insulin levels and estimates of insulin resistance were only observed in our adult study, suggesting that the effects of IL-18 are only associated with increasing age. Taken together with the association of IL18 variants with post-prandial measures, this provides support for IL-18 as a metabolic factor.

Mediterranean diet is inversely associated with steatosis and fibrosis and decreases ten-year diabetes and cardiovascular risk in NAFLD subjects: Results from the ATTICA prospective cohort study.

BACKGROUND AND AIMS: We assessed the association of Mediterranean diet with NAFLD and their interaction in predicting ten-year diabetes onset and first fatal/non-fatal cardiovascular disease (CVD) incidence. METHODS: The ATTICA prospective observational study in Athens, Greece included 1,514 men and 1,528 women (>18 years old) free-of-CVD at baseline. Liver steatosis and fibrosis indices were calculated. Mediterranean diet adherence was assessed through MedDietScore. At the ten-year follow-up visit, CVD evaluation was performed in an a priori specified subgroup of n = 2,020 participants and diabetes onset in n = 1,485 free-of-diabetes participants. RESULTS: MedDietScore was inversely associated with steatosis and fibrosis; e.g. in the case of the TyG index the Odds Ratio (OR) of the 3rd vs. 1st MedDietScore tertile was = 0·53, [95% Confidence Interval (95% CI) (0·29, 0·95)] and the associations persisted in multi-adjusted models. NAFLD predicted incident diabetes prospectively over a ten year period [HR = 1·87, 95% CI (0·75, 4·61)] and the association remained significant only in subjects with low MedDietScore (below median) whereas diabetes onset among subjects with higher MedDietScore was not influenced by NAFLD. Similarly, NAFLD predicted CVD [Hazard Ratio (HR) = 3·01, 95%CI(2·28, 3·95)]; the effect remained significant only in subjects with MedDietScore below median [HR = 1·38, 95% CI (1·00, 1·93)] whereas it was essentially null [HR = 1·00,95% CI (0·38, 2·63)] among subjects with higher score. Mediation analysis revealed that adiponectin and adiponectin-to-leptin ratio were the strongest mediators. CONCLUSIONS: We report an inverse association between Mediterranean diet and NAFLD. Mediterranean diet protected against diabetes and CVD prospectively among subjects with NAFLD.

Day/night variations of high-molecular-weight adiponectin and lipocalin-2 in healthy men studied under fed and fasted conditions.

AIMS/HYPOTHESIS: Adiponectin and lipocalin-2 are adipocyte-derived plasma proteins that have been proposed to have opposite effects on insulin sensitivity. Given the epidemiological, physiological and molecular links between sleep, the circadian timing system and glucose metabolism, the aim of this study was to assess effects of the sleep/wake cycle and the fasting/feeding cycle on high-molecular-weight adiponectin (HMW-adiponectin; the biologically active form) and lipocalin-2. We also aimed to compare the 24 h rhythms in the levels of these proteins with those of cortisol, leptin, leptin-binding protein and total adiponectin. METHODS: Lean men underwent a 3 day in-laboratory study, either in the fed state (n = 8, age: 20.9 ± 2.1 years, BMI: 22.8 ± 2.3 kg/m²) or fasting state (3 day fast, n = 4, age: 25.3 ± 3.9 years, BMI: 23.3 ± 2.2 kg/m²). The sleep episode was scheduled in darkness from 23:00 to 07:00 hours. Blood was sampled every 15 min for 24 h on the third day of each study. RESULTS: While fed, HMW-adiponectin and lipocalin-2 had large daily rhythms with troughs at night (HMW-adiponectin: ~04:00 hours, peak-to-trough amplitude 36%, p < 0.0001; lipocalin-2: ~04:00 hours, 40%, p < 0.0001). On the third day of fasting, the timing and relative amplitudes were unchanged (HMW-adiponectin: ~04:00 hours, 38%, p = 0.0014; lipocalin-2: ~05:00 hours, 38%, p = 0.0043). CONCLUSIONS/INTERPRETATION: These data show that HMW-adiponectin and lipocalin-2 both have significant day/night rhythms, both with troughs at night, that these are not driven by the feeding/fasting cycle, and that it is important to report and/or standardise the time of day for such assays. Further studies are required to determine whether the daily rhythm of HMW-adiponectin levels influences the daily rhythm of insulin sensitivity.