Diabetes incidence and glucose intolerance prevalence increase with higher outdoor temperature

OBJECTIVE

Rising global temperatures might contribute to the current worldwide diabetes epidemic, as higher ambient temperature can negatively impact glucose metabolism via a reduction in brown adipose tissue activity. Therefore, we examined the association between outdoor temperature and diabetes incidence in the USA as well as the prevalence of glucose intolerance worldwide.

RESEARCH DESIGN AND METHODS

Using meta-regression, we determined the association between mean annual temperature and diabetes incidence during 1996-2009 for each US state separately. Subsequently, results were pooled in a meta-analysis. On a global scale, we performed a meta-regression analysis to assess the association between mean annual temperature and the prevalence of glucose intolerance.

RESULTS

We demonstrated that, on average, per 1°C increase in temperature, age-adjusted diabetes incidence increased with 0.314 (95% CI 0.194 to 0.434) per 1000. Similarly, the worldwide prevalence of glucose intolerance increased by 0.170% (95% CI 0.107% to 0.234%) per 1°C rise in temperature. These associations persisted after adjustment for obesity.

CONCLUSIONS

Our findings indicate that the diabetes incidence rate in the USA and prevalence of glucose intolerance worldwide increase with higher outdoor temperature.

Growth hormone secretion is diminished and tightly controlled in humans enriched for familial longevity

Reduced growth hormone (GH) signaling has been consistently associated with increased health and lifespan in various mouse models. Here, we assessed GH secretion and its control in relation with human familial longevity. We frequently sampled blood over 24 h in 19 middle‐aged offspring of long‐living families from the Leiden Longevity Study together with 18 of their partners as controls. Circulating GH concentrations were measured every 10 min and insulin‐like growth factor 1 (IGF‐1) and insulin‐like growth factor binding protein 3 (IGFBP3) every 4 h. Using deconvolution analysis, we found that 24‐h total GH secretion was 28% lower (P = 0.04) in offspring [172 (128–216) mU L⁻¹] compared with controls [238 (193–284) mU L⁻¹]. We used approximate entropy (ApEn) to quantify the strength of feedback/feedforward control of GH secretion. ApEn was lower (P = 0.001) in offspring [0.45 (0.39–0.53)] compared with controls [0.66 (0.56–0.77)], indicating tighter control of GH secretion. No significant differences were observed in circulating levels of IGF‐1 and IGFBP3 between offspring and controls. In conclusion, GH secretion in human familial longevity is characterized by diminished secretion rate and more tight control. These data imply that the highly conserved GH signaling pathway, which has been linked to longevity in animal models, is also associated with human longevity.

Weight loss induced by very low calorie diet is associated with a more beneficial systemic inflammatory profile than by Roux-en-Y gastric bypass

INTRODUCTION

Weight loss interventions such as Roux-en-Y gastric bypass (RYGB) and very low calorie diets (VLCD) lead to improvement of glucose metabolism in obese individuals with type-2 diabetes. Weight loss can also positively influence the unfavorable inflammatory profile associated with obesity. However, a direct comparison of the effect of VLCD and RYGB on systemic inflammation is lacking.

METHODS

Systemic inflammation was investigated in age- and BMI-matched morbidly obese T2DM women by determining the number and activation- or memory status of peripheral blood leukocytes by flow cytometry, in addition to measuring circulating levels of cytokines and CRP. Systemic inflammation was assessed one month before and three months after RYGB (n=15) or VLCD (n=12). An age matched group of lean women (n=12) was studied as control group.

RESULTS

Three months after the intervention, CRP and leptin levels were reduced whereas adiponectin levels were increased both by RYGB and VLCD. TNF-α levels were increased by RYGB, but reduced by VLCD. IL-2 and IL-6 levels were reduced and IL-4 levels were increased by VLCD but not affected by RYGB. The number of activated peripheral cytotoxic T (CD8+CD25+) and B (CD19+CD38+) cells was significantly higher after RYGB than after VLCD.

CONCLUSION

In conclusion, RYGB and VLCD have differential effects on the activation status of peripheral leukocytes and levels of cytokines in obese women with T2DM, despite comparable weight loss three months after the intervention. VLCD seems to have more favorable effects on the inflammatory profile as compared to RYGB.

Energy restriction and Roux-en-Y gastric bypass reduce postprandial α-dicarbonyl stress in obese women with type 2 diabetes

AIMS/HYPOTHESIS

Dicarbonyl compounds are formed as byproducts of glycolysis and are key mediators of diabetic complications. However, evidence of postprandial α-dicarbonyl formation in humans is lacking, and interventions to reduce α-dicarbonyls have not yet been investigated. Therefore, we investigated postprandial α-dicarbonyl levels in obese women without and with type 2 diabetes. Furthermore, we evaluated whether a diet very low in energy (very low calorie diet [VLCD]) or Roux-en-Y gastric bypass (RYGB) reduces α-dicarbonyl stress in obese women with type 2 diabetes.

METHODS

In lean (n = 12) and obese women without (n = 27) or with type 2 diabetes (n = 27), we measured the α-dicarbonyls, methylglyoxal (MGO), glyoxal (GO) and 3-deoxyglucosone (3-DG), and glucose in fasting and postprandial plasma samples obtained during a mixed meal test. Obese women with type 2 diabetes underwent either a VLCD or RYGB. Three weeks after the intervention, individuals underwent a second mixed meal test.

RESULTS

Obese women with type 2 diabetes had higher fasting and particularly higher postprandial plasma α-dicarbonyl levels, compared with those without diabetes. After three weeks of a VLCD, postprandial α-dicarbonyl levels in diabetic women were significantly reduced (AUC MGO -14%, GO -16%, 3-DG -25%), mainly through reduction of fasting plasma α-dicarbonyls (MGO -13%, GO -13%, 3-DG -33%). Similar results were found after RYGB.

CONCLUSIONS/INTERPRETATION

This study shows that type 2 diabetes is characterised by increased fasting and postprandial plasma α-dicarbonyl stress, which can be reduced by improving glucose metabolism through a VLCD or RYGB. These data highlight the potential to reduce reactive α-dicarbonyls in obese individuals with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01167959.

Abstract P3-07-54: Insulin-like growth factor 1 receptor expression and polymorphism are associated with response to neoadjuvant chemotherapy in breast cancer patients: Results from the NEOZOTAC trial (BOOG 2010-01)

Background

The insulin-like growth factor 1 (IGF-1) pathway is involved in cell growth, proliferation and cell cycle progression and associated with tumor genesis and therapy resistance. This study aims to elucidate whether variation in the IGF-1 pathway is predictive for pathologic response in early breast cancer (BC) patients taking part in the phase III NEOZOTAC trial, randomizing between 6 cycles of neoadjuvant TAC chemotherapy with or without zoledronic acid.

Method

Formalin-fixed paraffin-embedded (FFPE) tissue samples of pre-chemotherapy biopsies and operation specimens were collected for analysis of IGF-1 receptor (IGF-1R) expression using IHC (n=216) and for analysis of 8 candidate SNPs in genes of the IGF-1 pathway (n=184) using OpenArray® RealTime PCR. Optionally, blood samples were collected immediately before chemotherapy for determination of glucose, insulin, IGF-1, IGF-2 and IGF-BP3. Associations with patient and tumor characteristics and chemotherapy response according to Miller and Payne (MP) pathologic response were performed using chi square and logistic regression analyses.

Results

High IGF-1R expression was associated with estrogen receptor expression (P=0.001). During chemotherapy, a significant number of the tumors (47.2%) showed a decrease in IGF-1R expression, while in a small number of the tumors an upregulation was seen (15.1%). IGF-1R expression before treatment was not associated with pathological response, however absence of IGF-1R expression after treatment was associated with a better response in multivariate analyses (P=0.012) and patients with a decrease in expression during treatment showed a better response to chemotherapy as well (P=0.008). Moreover, the variant T allele of 3129G>T in IGF-1R (rs2016347) was associated with a better pathological response in multivariate analyses (P=0.032). In addition, high glucose and insulin levels were associated with positive lymph node status before chemotherapy in multivariate analysis (P=0.019) and (P=0.031), respectively.

Conclusion

Neoadjuvant chemotherapy induced changes in the IGF-1R expression in most of the tumors. Absence or diminished expression of IGF-1R after treatment was associated with a better pathological response. Additionally, we found a SNP (rs2016347) in IGF-1R as a potential predictive marker for chemotherapy efficacy in BC patients treated with TAC. These findings may help to select patients who might benefit from (co-)treatment with an IGF-1 pathway inhibitor.

Citation Format: de Groot S, Charehbili A, van Laarhoven HWM, Mooyaart AL, Dekker-Ensink NG, van de Ven S, Janssen LGM, Swen JJ, Smit VTHBM, Heijns JB, Kessels LW, van der Straaten RJHM, Bhringer S, Gelderblom AJ, van der Hoeven JJM, Guchelaar HJ, Pijl H, Kroep JR. Insulin-like growth factor 1 receptor expression and polymorphism are associated with response to neoadjuvant chemotherapy in breast cancer patients: Results from the NEOZOTAC trial (BOOG 2010-01). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-54.

Loss-of-Function Mutations in the Cell-Cycle Control Gene CDKN2A Impact on Glucose Homeostasis in Humans

At the CDKN2A/B locus, three independent signals for type 2 diabetes risk are located in a noncoding region near CDKN2A. The disease-associated alleles have been implicated in reduced β-cell function, but the underlying mechanism remains elusive. In mice, β-cell-specific loss of Cdkn2a causes hyperplasia, while overexpression leads to diabetes, highlighting CDKN2A as a candidate effector transcript. Rare CDKN2A loss-of-function mutations are a cause of familial melanoma and offer the opportunity to determine the impact of CDKN2A haploinsufficiency on glucose homeostasis in humans. To test the hypothesis that such individuals have improved β-cell function, we performed oral and intravenous glucose tolerance tests on mutation carriers and matched control subjects. Compared with control subjects, carriers displayed increased insulin secretion, impaired insulin sensitivity, and reduced hepatic insulin clearance. These results are consistent with a model whereby CDKN2A loss affects a range of different tissues, including pancreatic β-cells and liver. To test for direct effects of CDKN2A-loss on β-cell function, we performed knockdown in a human β-cell line, EndoC-bH1. This revealed increased insulin secretion independent of proliferation. Overall, we demonstrated that CDKN2A is an important regulator of glucose homeostasis in humans, thus supporting its candidacy as an effector transcript for type 2 diabetes-associated alleles in the region.

Insulin-like growth factor 1 receptor expression and IGF1R 3129G > T polymorphism are associated with response to neoadjuvant chemotherapy in breast cancer patients: results from the NEOZOTAC trial (BOOG 2010-01)

Background

The insulin-like growth factor 1 (IGF-1) pathway is involved in cell growth and proliferation and is associated with tumorigenesis and therapy resistance. This study aims to elucidate whether variation in the IGF-1 pathway is predictive for pathologic response in early HER2 negative breast cancer (BC) patients, taking part in the phase III NEOZOTAC trial, randomizing between 6 cycles of neoadjuvant TAC chemotherapy with or without zoledronic acid.

Methods

Formalin-fixed paraffin-embedded tissue samples of pre-chemotherapy biopsies and operation specimens were collected for analysis of IGF-1 receptor (IGF-1R) expression (n = 216) and for analysis of 8 candidate single nucleotide polymorphisms (SNPs) in genes of the IGF-1 pathway (n = 184) using OpenArray® RealTime PCR. Associations with patient and tumor characteristics and chemotherapy response according to Miller and Payne pathologic response were performed using chi-square and regression analysis.

Results

During chemotherapy, a significant number of tumors (47.2 %) showed a decrease in IGF-1R expression, while in a small number of tumors an upregulation was seen (15.1 %). IGF-1R expression before treatment was not associated with pathological response, however, absence of IGF-1R expression after treatment was associated with a better response in multivariate analysis (P = 0.006) and patients with a decrease in expression during treatment showed a better response to chemotherapy as well (P = 0.020). Moreover, the variant T allele of 3129G > T in IGF1R (rs2016347) was associated with a better pathological response in multivariate analysis (P = 0.032).

Conclusions

Absent or diminished expression of IGF-1R after neoadjuvant chemotherapy was associated with a better pathological response. Additionally, we found a SNP (rs2016347) in IGF1R as a potential predictive marker for chemotherapy efficacy in BC patients treated with TAC.

Trial registration

ClinicalTrials.gov NCT01099436. Registered April 6, 2010.

Familial Longevity Is Not Associated with Major Differences in the Hypothalamic-Pituitary-Gonadal Axis in Healthy Middle-Aged Men

CONTEXT

A trade-off between fertility and longevity possibly exists. The association of the male hypothalamic-pituitary-gonadal (HPG) axis with familial longevity has not yet been investigated.

OBJECTIVE

To study 24-h hormone concentration profiles of the HPG axis in men enriched for familial longevity and controls.

DESIGN

We frequently sampled blood over 24 h in 10 healthy middle-aged male offspring of nonagenarian participants from the Leiden Longevity Study together with 10 male age-matched controls. Individual 24-h luteinizing hormone (LH) and testosterone concentration profiles were analyzed by deconvolution analyses to estimate secretion parameters. Furthermore, the temporal relationship between LH and testosterone was assessed by cross-correlation analysis. We used (cross-)approximate entropy to quantify the strength of feedback and/or feedforward control of LH and testosterone secretion.

RESULTS

Mean [95% confidence interval (CI)] total LH secretion of the offspring was 212 (156-268) U/L/24 h, which did not differ significantly (p = 0.51) from the total LH secretion of controls [186 (130-242) U/L/24 h]. Likewise, mean (95% CI) total testosterone secretion of the offspring [806 (671-941) nmol/L/24 h] and controls [811 (676-947) nmol/L/24 h] were similar (p = 0.95). Other parameters of LH and testosterone secretion were also not significantly different between offspring and controls. The temporal relationship between LH and testosterone and the strength of feedforward/feedback regulation within the HPG axis were similar between offspring of long-lived families and controls.

CONCLUSION

This relatively small study suggests that in healthy male middle-aged participants, familial longevity is not associated with major differences in the HPG axis. Selection on both fertility and health may in part explain the results.

Central GLP-1 receptor signalling accelerates plasma clearance of triacylglycerol and glucose by activating brown adipose tissue in mice

AIMS/HYPOTHESIS

Glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) agonism, used in the treatment of type 2 diabetes, has recently been shown to increase thermogenesis via the brain. As brown adipose tissue (BAT) produces heat by burning triacylglycerol (TG) and takes up glucose for de novo lipogenesis, the aim of this study was to evaluate the potential of chronic central GLP-1R activation by exendin-4 to facilitate clearance of lipids and glucose from the circulation by activating BAT.

METHODS

Lean and diet-induced obese (DIO) C57Bl/6J mice were used to explore the effect of a 5 day intracerebroventricular infusion of the GLP-1 analogue exendin-4 or vehicle on lipid and glucose uptake by BAT in both insulin-sensitive and insulin-resistant conditions.

RESULTS

Central administration of exendin-4 in lean mice increased sympathetic outflow towards BAT and white adipose tissue (WAT), resulting in increased thermogenesis as evidenced by increased uncoupling protein 1 (UCP-1) protein levels and decreased lipid content, while the uptake of TG-derived fatty acids was increased in both BAT and WAT. Interestingly, in DIO mice, the effects on WAT were blunted, while exendin-4 still increased sympathetic outflow towards BAT and increased the uptake of plasma TG-derived fatty acids and glucose by BAT. These effects were accompanied by increased fat oxidation, lower plasma TG and glucose concentrations, and reduced body weight.

CONCLUSIONS/INTERPRETATION

Collectively, our results suggest that BAT activation may be a major contributor to the glucose- and TG-lowering effects of GLP-1R agonism.

The effects of short-term fasting on tolerance to (neo) adjuvant chemotherapy in HER2-negative breast cancer patients: a randomized pilot study

BACKGROUND

Preclinical evidence shows that short-term fasting (STF) protects healthy cells against side effects of chemotherapy and makes cancer cells more vulnerable to it. This pilot study examines the feasibility of STF and its effects on tolerance of chemotherapy in a homogeneous patient group with early breast cancer (BC).

METHODS

Eligible patients had HER2-negative, stage II/III BC. Women receiving (neo)-adjuvant TAC (docetaxel/doxorubicin/cyclophosphamide) were randomized to fast 24 h before and after commencing chemotherapy, or to eat according to the guidelines for healthy nutrition. Toxicity in the two groups was compared. Chemotherapy-induced DNA damage in peripheral blood mononuclear cells (PBMCs) was quantified by the level of γ-H2AX analyzed by flow cytometry.

RESULTS

Thirteen patients were included of whom seven were randomized to the STF arm. STF was well tolerated. Mean erythrocyte- and thrombocyte counts 7 days post-chemotherapy were significantly higher (P = 0.007, 95 % CI 0.106-0.638 and P = 0.00007, 95 % CI 38.7-104, respectively) in the STF group compared to the non-STF group. Non-hematological toxicity did not differ between the groups. Levels of γ-H2AX were significantly increased 30 min post-chemotherapy in CD45 + CD3- cells in non-STF, but not in STF patients.

CONCLUSIONS

STF during chemotherapy was well tolerated and reduced hematological toxicity of TAC in HER2-negative BC patients. Moreover, STF may reduce a transient increase in, and/or induce a faster recovery of DNA damage in PBMCs after chemotherapy. Larger studies, investigating a longer fasting period, are required to generate more insight into the possible benefits of STF during chemotherapy.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01304251 , March 2011.

Paleolithic nutrition for metabolic syndrome: systematic review and meta-analysis

BACKGROUND

Paleolithic nutrition, which has attracted substantial public attention lately because of its putative health benefits, differs radically from dietary patterns currently recommended in guidelines, particularly in terms of its recommendation to exclude grains, dairy, and nutritional products of industry.

OBJECTIVE

We evaluated whether a Paleolithic nutritional pattern improves risk factors for chronic disease more than do other dietary interventions.

DESIGN

We conducted a systematic review of randomized controlled trials (RCTs) that compared the Paleolithic nutritional pattern with any other dietary pattern in participants with one or more of the 5 components of metabolic syndrome. Two reviewers independently extracted study data and assessed risk of bias. Outcome data were extracted from the first measurement time point (≤6 mo). A random-effects model was used to estimate the average intervention effect. The quality of the evidence was rated with the use of the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Four RCTs that involved 159 participants were included. The 4 control diets were based on distinct national nutrition guidelines but were broadly similar. Paleolithic nutrition resulted in greater short-term improvements than did the control diets (random-effects model) for waist circumference (mean difference: -2.38 cm; 95% CI: -4.73, -0.04 cm), triglycerides (-0.40 mmol/L; 95% CI: -0.76, -0.04 mmol/L), systolic blood pressure (-3.64 mm Hg; 95% CI: -7.36, 0.08 mm Hg), diastolic blood pressure (-2.48 mm Hg; 95% CI: -4.98, 0.02 mm Hg), HDL cholesterol (0.12 mmol/L; 95% CI: -0.03, 0.28 mmol/L), and fasting blood sugar (-0.16 mmol/L; 95% CI: -0.44, 0.11 mmol/L). The quality of the evidence for each of the 5 metabolic components was moderate. The home-delivery (n = 1) and dietary recommendation (n = 3) RCTs showed similar effects with the exception of greater improvements in triglycerides relative to the control with the home delivery. None of the RCTs evaluated an improvement in quality of life.

CONCLUSIONS

The Paleolithic diet resulted in greater short-term improvements in metabolic syndrome components than did guideline-based control diets. The available data warrant additional evaluations of the health benefits of Paleolithic nutrition. This systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42014015119.

Familial Longevity Is Associated With Higher TSH Secretion and Strong TSH-fT3 Relationship

CONTEXT

Longevity is associated with changes in circulating levels of thyroid hormone (TH) and/or TSH in animals and humans, but underlying mechanisms remain elusive.

OBJECTIVE

We explored in 38 offspring of nonagenarian participants from the Leiden Longevity Study, who are enriched for longevity and in their partners, ultradian and circadian rhythmicity of TSH, temporal relationship, and feedback and forward interplay between TSH and TH.

METHODS

We collected blood samples every 10 minutes for 24 hours for TSH and TH profiles. We used a deconvolution analysis to estimate basal (nonpulsatile), pulsatile, and other secretion parameters to characterize ultradian rhythmicity and locally weighted polynomial regression of TSH to assess circadian rhythmicity. A cross-correlation analysis was used to investigate the temporal relationship between TSH and TH and cross-approximate entropy to assess feedback and forward interplay between TSH and TH.

RESULTS

Compared with partners, offspring displayed higher mean (95% confidence interval [CI]) basal TSH secretion (34.3 [95% CI 27.2-43.1] mU/L per 24 hours vs 18.5 [95% CI 14.4-23.7] mU/L per 24 hours, P = .001) but no differences in ultradian or circadian properties of TSH. The temporal relationship between TSH and free T3 at zero delay was higher in offspring (0.48 ± 0.2) compared with partners (0.26 ± 0.4) (P = .05), but the feedback and forward interplay between TSH and TH did not differ.

CONCLUSIONS

Familial longevity is associated with increased basal TSH secretion and a strong temporal relationship between TSH and free T3 but not with differences in ultradian or circadian TSH rhythmicity or feedback and forward interplay between TSH and TH.

Increased PUFA Content and 5-Lipoxygenase Pathway Expression Are Associated with Subcutaneous Adipose Tissue Inflammation in Obese Women with Type 2 Diabetes

Obese women with type 2 diabetes mellitus (T2DM) have more inflammation in their subcutaneous white adipose tissue (sWAT) than age-and-BMI similar obese women with normal glucose tolerance (NGT). We aimed to investigate whether WAT fatty acids and/or oxylipins are associated with the enhanced inflammatory state in WAT of the T2DM women. Fatty acid profiles were measured in both subcutaneous and visceral adipose tissue (vWAT) of 19 obese women with NGT and 16 age-and-BMI similar women with T2DM. Oxylipin levels were measured in sWAT of all women. Arachidonic acid (AA) and docosahexaenoic acid (DHA) percentages were higher in sWAT, but not vWAT of the T2DM women, and AA correlated positively to the gene expression of macrophage marker CD68. We found tendencies for higher oxylipin concentrations of the 5-LOX leukotrienes in sWAT of T2DM women. Gene expression of the 5-LOX leukotriene biosynthesis pathway was significantly higher in sWAT of T2DM women. In conclusion, AA and DHA content were higher in sWAT of T2DM women and AA correlated to the increased inflammatory state in sWAT. Increased AA content was accompanied by an upregulation of the 5-LOX pathway and seems to have led to an increase in the conversion of AA into proinflammatory leukotrienes in sWAT.

Exploratory analysis of candidate germline gene polymorphisms in breast cancer patients treated with neoadjuvant anthracycline-containing chemotherapy and associations with febrile neutropenia

AIM

SNPs may be associated with (side) effects of chemotherapy and may be useful as biomarkers to predict febrile neutropenia.

PATIENTS & METHODS

187 DNA samples extracted from formalin-fixed paraffin-embedded tissue from patients with stage II/III HER2-negative breast cancer were genotyped.

RESULTS

Candidate SNPs were selected and explored for association with febrile neutropenia and/or pathological complete response. TT genotype of 388 C>T in FGFR4 (rs351855) had a tendency toward higher incidence of febrile neutropenia during neoadjuvant chemotherapy, compared with the CT (p = 0.383) genotype and compared with the CC genotype (p = 0.068).

CONCLUSION

The TT genotype of 388 C>T FGFR4 may be related to incidence of febrile neutropenia during neoadjuvant TAC (docetaxel, doxorubicin, cyclophosphamide) chemotherapy and is possibly useful as a patient-related risk factor when assessing febrile neutropenia risk. Original submitted 23 January 2015; Revision submitted 26 May 2015.

Human longevity is characterised by high thyroid stimulating hormone secretion without altered energy metabolism

Few studies have included subjects with the propensity to reach old age in good health, with the aim to disentangle mechanisms contributing to staying healthier for longer. The hypothalamic-pituitary-thyroid (HPT) axis maintains circulating levels of thyroid stimulating hormone (TSH) and thyroid hormone (TH) in an inverse relationship. Greater longevity has been associated with higher TSH and lower TH levels, but mechanisms underlying TSH/TH differences and longevity remain unknown. The HPT axis plays a pivotal role in growth, development and energy metabolism. We report that offspring of nonagenarians with at least one nonagenarian sibling have increased TSH secretion but similar bioactivity of TSH and similar TH levels compared to controls. Healthy offspring and spousal controls had similar resting metabolic rate and core body temperature. We propose that pleiotropic effects of the HPT axis may favour longevity without altering energy metabolism.

Abstract P3-06-50: Thyroid function is associated with the response to neoadjuvant chemotherapy in breast cancer patients: Results from the NEOZOTAC trial on behalf of the Dutch Breast Cancer Research Group (BOOG 2010-01)

Background: Thyroid hormones, regulators of metabolism and development in healthy tissue, stimulate tumor growth in vitro and are associated with breast cancer risk. We investigated the effect of chemotherapy on thyroid function and the extent to which it can predict the pathological response in patients with HER2 negative stage II/III breast cancer taking part in the NEOZOTAC phase III trial, randomizing between 6 cycles of neoadjuvant TAC chemotherapy with or without additional zoledronic acid. Moreover, we examined the impact of thyroid function on chemotherapy toxicity.

Methods: Serum samples of 38 of the 105 patients who participated in the side study of the NEOZOTAC trial were available for analyses. Serum free thyroxin (fT4) and thyroid stimulating hormone (TSH) levels were measured at baseline and compared with fT4 and TSH levels before the 2nd and 6th chemotherapy cycle. FT4 and TSH levels were also compared between subjects with and without pathological complete response (pCR). The relation between toxicity, per side effect of any CTC grade, and the variation in fT4 and TSH levels during chemotherapy was tested.

Results: Serum samples at baseline, before the 2nd chemotherapy cycle and at end of treatment were available for 31, 30 and 21 patients, respectively. In the total population, the mean baseline fT4 level was 16,0pmol/L and the mean TSH level 1,11mU/L. There were no differences between subjects solely treated with TAC chemotherapy and subjects treated with zoledronic acid as an adjunct to TAC with respect to the mean fT4 and TSH at each time point. Baseline TSH levels tended to be higher in patients who achieved pCR (p=0.035 univariate analysis and p=0.074 multivariate analysis) (Table 1). During 6 cycles of chemotherapy, fT4 levels decreased (p<0.000) and TSH levels increased significantly (p=0.019). Interestingly, the decrease of fT4 was significantly greater in patients without nausea, vomiting or sensory neuropathy, than in patients with those side effects (p=0.037, p=0.043 and p=0.050 respectively).

CharacteristicUnivariate analysisMultivariate analysis OR95%CIP valueOR95%CIP valueN stage: N0 vs. N+0.330.03-3.640.368T stage: <5cm vs. >5cm0.330.03-3.630.333ER receptor: Pos vs. Neg2.560.20-33.10.473fT40.780.43-1.420.4170.660.33-1.290.581TSH3.241.09-9.700.03517.30.76-3910.074Table 1. Univariate and multivariate logistic regression models of baseline characteristics and TSH and fT4 predictive of pCR.

Conclusion: TSH levels at baseline were higher in breast cancer patients with pCR. Chemotherapy blunts thyroid function, and a large decline of fT4 was associated with less side effects. These data suggest that thyroid hormones may interact with chemotherapy to modulate treatment (side-) effects in patients with breast cancer.

Citation Format: S de Groot, A Charehbili, L GM Janssen, E M Dijkgraaf, V THBM Smit, L W Kessels, A van Bochove, H WM van Laarhoven, E Meershoek-Klein Kranenbarg, A E van Leeuwen-Stok, G J Liefers, C JH van de Velde, J WR Nortier, J JM van der Hoeven, H Pijl, J R Kroep. Thyroid function is associated with the response to neoadjuvant chemotherapy in breast cancer patients: Results from the NEOZOTAC trial on behalf of the Dutch Breast Cancer Research Group (BOOG 2010-01) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-50.

The effects of sodium oxybate on core body and skin temperature regulation in narcolepsy

Patients suffering from narcolepsy type 1 show altered skin temperatures, resembling the profile that is related to sleep onset in healthy controls. The aim of the present study is to investigate the effects of sodium oxybate, a widely used drug to treat narcolepsy, on the 24-h profiles of temperature and sleep-wakefulness in patients with narcolepsy and controls. Eight hypocretin-deficient male narcolepsy type 1 patients and eight healthy matched controls underwent temperature measurement of core body and proximal and distal skin twice, and the sleep-wake state for 24 h. After the baseline assessment, 2 × 3 g of sodium oxybate was administered for 5 nights, immediately followed by the second assessment. At baseline, daytime core body temperature and proximal skin temperature were significantly lower in patients with narcolepsy (core: 36.8 ± 0.05 °C versus 37.0 ± 0.05 °C, F = 8.31, P = 0.01; proximal: 33.4 ± 0.26 °C versus 34.3 ± 0.26 °C, F = 5.66, P = 0.03). In patients, sodium oxybate administration increased proximal skin temperature during the day (F = 6.46, P = 0.04) to a level similar as in controls, but did not affect core body temperature, distal temperature or distal-proximal temperature gradient. Sodium oxybate administration normalised the predictive value of distal skin temperature and distal-proximal temperature gradient for the onset of daytime naps (P < 0.01). In conclusion, sodium oxybate administration resulted in a partial normalisation of the skin temperature profile, by increasing daytime proximal skin temperature, and by strengthening the known relationship between skin temperature and daytime sleep propensity. These changes seem to be related to the clinical improvement induced by sodium oxybate treatment. A causal relationship is not proven.

Cardiovascular flexibility in middle-aged overweight South Asians vs. white Caucasians: response to short-term caloric restriction

BACKGROUND AND AIMS

South Asians have a higher risk of developing cardiovascular disease than white Caucasians. The underlying cause is unknown, but might be related to higher cardiac susceptibility to metabolic disorders. Short-term caloric restriction (CR) can be used as a metabolic stress test to study cardiac flexibility. We assessed whether metabolic and functional cardiovascular flexibility to CR differs between South Asians and white Caucasians.

METHODS AND RESULTS

Cardiovascular function and myocardial triglycerides were assessed using a 1.5T-MRI/S-scanner in 12 middle-aged overweight male South Asians and 12 matched white Caucasians before and after an 8-day very low calorie diet (VLCD). At baseline South Asians were more insulin resistant than Caucasians. Cardiac dimensions were smaller, despite correction for body surface area, and pulse wave velocity (PWV) in the distal aorta was higher in South Asians. Systolic and diastolic function, myocardial triglycerides and pericardial fat did not differ significantly between groups. After the VLCD body weight reduced on average by 4.0 ± 0.2 kg. Myocardial triglycerides increased in both ethnicities by 69 ± 18%, and diastolic function decreased although this was not significant in South Asians. However, pericardial fat and PWV in the proximal and total aorta were reduced in Caucasians only.

CONCLUSION

Myocardial triglyceride stores in middle-aged overweight and insulin resistant South Asians are as flexible and amenable to therapeutic intervention by CR as age-, sex- and BMI-matched but less insulin resistant white Caucasians. However, paracardial fat volume and PWV showed a differential effect in response to an 8-day VLCD in favor of Caucasians.

CLINICAL TRIAL REGISTRATION

NTR 2473 (URL: http://www.trialregister.nl/trialreg/admin/rctsearch.asp?Term=2473).

Middle-aged overweight South Asian men exhibit a different metabolic adaptation to short-term energy restriction compared with Europeans

AIMS/HYPOTHESIS

South Asians have a higher risk of developing type 2 diabetes than Europeans. The underlying cause of this excess risk is still poorly understood but might be related to differences in the regulation of energy/nutrient-sensing pathways in metabolic tissues and subsequent changes in whole-body substrate metabolism. In this study, we investigated the whole-body and skeletal muscle metabolic adaptations to short-term energy restriction in South Asian and European volunteers.

METHODS

Twenty-four middle-aged overweight South Asian and European men underwent a two-step hyperinsulinaemic-euglycaemic clamp, with skeletal muscle biopsies and indirect calorimetry before and after an 8 day diet very low in energy (very low calorie diet [VLCD]). Abdominal fat distribution and hepatic triacylglycerol content were assessed using MRI and MR spectroscopy.

RESULTS

South Asian men had higher hepatic triacylglycerol content than European men, and exhibited elevated clamp insulin levels that probably reflect a lower insulin clearance rate. Despite higher insulin levels, endogenous glucose production rate was similar and glucose disposal rate (Rd) and nonoxidative glucose disposal rate (NOGD) were significantly lower in South Asian than European men, indicating impaired whole-body insulin sensitivity. Energy restriction decreased abdominal fat mass and hepatic triacylglycerol content in both groups. However, the shift induced by energy restriction from glucose towards lipid oxidation observed in European men was impaired in South Asian men, indicating whole-body metabolic inflexibility. Remarkably, although energy restriction improved hepatic insulin sensitivity in both groups, Rd improved only in South Asian men owing to higher NOGD. At the molecular level, an increase in insulin-induced activation of the skeletal muscle mTOR pathway was found in South Asian men, showing that skeletal muscle energy/nutrient-sensing pathways were differentially affected by energy restriction.

CONCLUSIONS/INTERPRETATION

We conclude that South Asian men exhibit a different metabolic adaptation to short-term energy restriction than European men.

TRIAL REGISTRATION

Dutch trial registry ( www.trialregister.nl ), trial number NTR 2473.

Calorie restriction and Roux-en-Y gastric bypass have opposing effects on circulating FGF21 in morbidly obese subjects

OBJECTIVE

To study the effect of different weight loss strategies on levels of the metabolic regulator FGF21 in morbidly obese females with normal glucose tolerance (NGT) or type 2 diabetes mellitus (T2DM).

DESIGN

Observational intervention trial.

PATIENTS AND MEASUREMENTS

Weight reduction was achieved by Gastric Banding (GB, n = 11) or Roux-en-Y Gastric Bypass (RYGB, n = 16) in subjects with NGT, and by RYGB (n = 15) or a very-low-calorie diet (VLCD, n = 12) in type 2 diabetics. Fasted and/or postprandial levels of FGF21, FGF19 (an FGF21-related postprandial hormone) and bile salts (implicated in regulation of FGF21 and FGF19 expression) were measured before, and 3 and 12 weeks after intervention.

RESULTS

Fasted FGF21 levels were elevated in T2DM subjects. Calorie restriction by either GB or VLCD lowered bile salt and FGF21 levels. In contrast, RYGB surgery was associated with elevated bile salt and FGF21 levels.

CONCLUSIONS

Calorie restriction and RYGB have opposite effects on serum bile salt and FGF21 levels. Calorie restriction results in FGF21 approaching nonobese control levels, suggesting that this intervention is effective in reducing the "nutritional crisis" that appears to underly FGF21 elevation in obesity. FGF21 elevation after RYGB may contribute to the beneficial effect of this procedure.

Roux-en-Y gastric bypass surgery, but not calorie restriction, reduces plasma branched-chain amino acids in obese women independent of weight loss or the presence of type 2 diabetes

OBJECTIVE

Obesity and type 2 diabetes mellitus (T2DM) have been associated with increased levels of circulating branched-chain amino acids (BCAAs) that may be involved in the pathogenesis of insulin resistance. However, weight loss has not been consistently associated with the reduction of BCAA levels.

RESEARCH DESIGN AND METHODS

We included 30 obese normal glucose-tolerant (NGT) subjects, 32 obese subjects with T2DM, and 12 lean female subjects. Obese subjects underwent either a restrictive procedure (gastric banding [GB], a very low-calorie diet [VLCD]), or a restrictive/bypass procedure (Roux-en-Y gastric bypass [RYGB] surgery). Fasting blood samples were taken for the determination of amine group containing metabolites 4 weeks before, as well as 3 weeks and 3 months after the intervention.

RESULTS

BCAA levels were higher in T2DM subjects, but not in NGT subjects, compared with lean subjects. Principal component (PC) analysis revealed a concise PC consisting of all BCAAs, which showed a correlation with measures of insulin sensitivity and glucose tolerance. Only after the RYGB procedure, and at both 3 weeks and 3 months, were circulating BCAA levels reduced.

CONCLUSIONS

Our data confirm an association between deregulation of BCAA metabolism in plasma and insulin resistance and glucose intolerance. Three weeks after undergoing RYGB surgery, a significant decrease in BCAAs in both NGT as well as T2DM subjects was observed. After 3 months, despite inducing significant weight loss, neither GB nor VLCD induced a reduction in BCAA levels. Our results indicate that the bypass procedure of RYGB surgery, independent of weight loss or the presence of T2DM, reduces BCAA levels in obese subjects.

Regulation of skeletal muscle energy/nutrient-sensing pathways during metabolic adaptation to fasting in healthy humans

During fasting, rapid metabolic adaptations are required to maintain energy homeostasis. This occurs by a coordinated regulation of energy/nutrient-sensing pathways leading to transcriptional activation and repression of specific sets of genes. The aim of the study was to investigate how short-term fasting affects whole body energy homeostasis and skeletal muscle energy/nutrient-sensing pathways and transcriptome in humans. For this purpose, 12 young healthy men were studied during a 24-h fast. Whole body glucose/lipid oxidation rates were determined by indirect calorimetry, and blood and skeletal muscle biopsies were collected and analyzed at baseline and after 10 and 24 h of fasting. As expected, fasting induced a time-dependent decrease in plasma insulin and leptin levels, whereas levels of ketone bodies and free fatty acids increased. This was associated with a metabolic shift from glucose toward lipid oxidation. At the molecular level, activation of the protein kinase B (PKB/Akt) and mammalian target of rapamycin pathways was time-dependently reduced in skeletal muscle during fasting, whereas the AMP-activated protein kinase activity remained unaffected. Furthermore, we report some changes in the phosphorylation and/or content of forkhead protein 1, sirtuin 1, and class IIa histone deacetylase 4, suggesting that these pathways might be involved in the transcriptional adaptation to fasting. Finally, transcriptome profiling identified genes that were significantly regulated by fasting in skeletal muscle at both early and late time points. Collectively, our study provides a comprehensive map of the main energy/nutrient-sensing pathways and transcriptomic changes during short-term adaptation to fasting in human skeletal muscle.

Downregulation of the acetyl-CoA metabolic network in adipose tissue of obese diabetic individuals and recovery after weight loss

AIMS/HYPOTHESIS

Not all obese individuals develop type 2 diabetes. Why some obese individuals retain normal glucose tolerance (NGT) is not well understood. We hypothesise that the biochemical mechanisms that underlie the function of adipose tissue can help explain the difference between obese individuals with NGT and those with type 2 diabetes.

METHODS

RNA sequencing was used to analyse the transcriptome of samples extracted from visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) of obese women with NGT or type 2 diabetes who were undergoing bariatric surgery. The gene expression data was analysed by bioinformatic visualisation and statistical analyses techniques.

RESULTS

A network-based approach to distinguish obese individuals with NGT from obese individuals with type 2 diabetes identified acetyl-CoA metabolic network downregulation as an important feature in the pathophysiology of type 2 diabetes in obese individuals. In general, genes within two reaction steps of acetyl-CoA were found to be downregulated in the VAT and SAT of individuals with type 2 diabetes. Upon weight loss and amelioration of metabolic abnormalities three months following bariatric surgery, the expression level of these genes recovered to levels seen in individuals with NGT. We report four novel genes associated with type 2 diabetes and recovery upon weight loss: ACAT1 (encoding acetyl-CoA acetyltransferase 1), ACACA (encoding acetyl-CoA carboxylase α), ALDH6A1 (encoding aldehyde dehydrogenase 6 family, member A1) and MTHFD1 (encoding methylenetetrahydrofolate dehydrogenase).

CONCLUSIONS/INTERPRETATION

Downregulation of the acetyl-CoA network in VAT and SAT is an important feature in the pathophysiology of type 2 diabetes in obese individuals. ACAT1, ACACA, ALDH6A1 and MTHFD1 represent novel biomarkers in adipose tissue associated with type 2 diabetes in obese individuals.

Effects of bariatric surgery on pericardial ectopic fat depositions and cardiovascular function

OBJECTIVE

Cardiac ectopic fat depositions are thought to play a role in the pathogenesis of cardiovascular disease (CVD), the main cause of death in patients with type 2 diabetes. Diet-induced weight loss results in a decrease in cardiac ectopic fat stores, however if this is the same for surgically induced weight loss is less clear. Therefore, we assessed myocardial triglyceride (TG) content, pericardial fat and cardiac function in obese patients with insulin-dependent type 2 diabetes before and 16 weeks after Roux-en-Y gastric bypass (RYGB) surgery.

PATIENTS

Ten obese patients with insulin-dependent type 2 diabetes [40% male, age 53·7 ± 8·9 years (mean ± SD)] scheduled to undergo RYGB surgery were included.

MEASUREMENTS

Ectopic fat accumulation and cardiovascular function were assessed with magnetic resonance (MR) imaging and myocardial TG content with MR spectroscopy before and 16 weeks after RYGB surgery.

RESULTS

Body mass index decreased from 41·3 ± 4·3 at baseline to 34·1 ± 2·8 kg/m(2) (P < 0·001) after 16 weeks. Glycemic control improved as well [HbA1c: 7·8 ± 1·1 to 6·8 ± 1·3% (62 ± 12 to 51 ± 14 mm) (P < 0·05)]. We did not observe an effect of the RYGB surgery on myocardial TG content, cardiac function or pulse wave velocity. There was a greater relative decrease in visceral (-35·5 ± 9·6%) as compared to subcutaneous fat volume (-25·0 ± 6·3%) and in paracardial (-17·3 ±17·2%) as compared to epicardial fat volume (-6·4 ± 6·0%).

CONCLUSIONS

This study shows that surgical-induced weight loss leads to a larger decrease in paracardial than epicardial fat. Myocardial TG and cardiovascular function did not change.

The insulin sensitizing effect of topiramate involves KATP channel activation in the central nervous system

BACKGROUND AND PURPOSE

Topiramate improves insulin sensitivity, in addition to its antiepileptic action. However, the underlying mechanism is unknown. Therefore, the present study was aimed at investigating the mechanism of the insulin-sensitizing effect of topiramate both in vivo and in vitro.

EXPERIMENTAL APPROACH

Male C57Bl/6J mice were fed a run-in high-fat diet for 6 weeks, before receiving topiramate or vehicle mixed in high-fat diet for an additional 6 weeks. Insulin sensitivity was assessed by hyperinsulinaemic-euglycaemic clamp. The extent to which the insulin sensitizing effects of topiramate were mediated through the CNS were determined by concomitant i.c.v. infusion of vehicle or tolbutamide, an inhibitor of ATP-sensitive potassium channels in neurons. The direct effects of topiramate on insulin signalling and glucose uptake were assessed in vivo and in cultured muscle cells.

KEY RESULTS

In hyperinsulinaemic-euglycaemic clamp conditions, therapeutic plasma concentrations of topiramate (∼4 μg·mL(-1) ) improved insulin sensitivity (glucose infusion rate + 58%). Using 2-deoxy-D-[(3) H]glucose, we established that topiramate improved the insulin-mediated glucose uptake by heart (+92%), muscle (+116%) and adipose tissue (+586%). Upon i.c.v. tolbutamide, the insulin-sensitizing effect of topiramate was completely abrogated. Topiramate did not directly affect glucose uptake or insulin signalling neither in vivo nor in cultured muscle cells.

CONCLUSION AND IMPLICATIONS

In conclusion, topiramate stimulates insulin-mediated glucose uptake in vivo through the CNS. These observations illustrate the possibility of pharmacological modulation of peripheral insulin resistance through a target in the CNS.

Resting-state functional connectivity of brain regions involved in cognitive control, motivation, and reward is enhanced in obese females

BACKGROUND

The brain is crucial for the control of food intake, reward, and energy homeostasis.

OBJECTIVE

We hypothesized that 1) brain circuits involved in energy homeostasis and reward show different functional connectivity patterns between obese and lean individuals and 2) food intake affects functional connectivity differentially in obese and lean individuals. Therefore, we compared the connectivity of the hypothalamus, amygdala, and posterior cingulate cortex, each probing a distinct network related to energy homeostasis and reward, between obese subjects and lean subjects in the fasting state and after meal ingestion.

DESIGN

We acquired 3 Tesla resting-state functional magnetic resonance imaging scans after an overnight fast and after ingestion of a liquid mixed meal in 46 obese female participants [19 with normal glucose tolerance and 27 with type 2 diabetes mellitus (T2DM)] and 12 lean subjects. Functional connectivity of our regions of interest was assessed by using a seed-based correlation approach.

RESULTS

No significant differences between normal-glucose-tolerant and T2DM subjects were observed. In the fasting state, the total obese group had stronger hypothalamic connectivity with the medial prefrontal cortex and the dorsal striatum than did the lean subjects. The amygdala was differentially connected to the right insula in obese compared with lean subjects. Food intake dampened hypothalamic connectivity with the frontal regions in lean subjects, whereas these connections were barely affected in obese subjects.

CONCLUSIONS

Our results indicate that functional connectivity in several brain networks, particularly the homeostatic and cognitive control network and the reward network, was different between obese and lean subjects. In the fasting state, obesity appears to be associated with stronger functional connectivity between brain areas involved in cognitive control, motivation, and reward, whereas these connections are largely unaffected by food intake in obese compared with lean subjects.

Sex-specific effects of naturally occurring variants in the dopamine receptor D2 locus on insulin secretion and type 2 diabetes susceptibility

AIMS

Modulation of dopamine receptor D2 (DRD2) activity affects insulin secretion in both rodents and isolated pancreatic β-cells. We hypothesized that single nucleotide polymorphisms in the DRD2/ANKK1 locus may affect susceptibility to type 2 diabetes in humans.

METHODS

Four potentially functional variants in the coding region of the DRD2/ANKK1 locus (rs1079597, rs6275, rs6277, rs1800497) were genotyped and analysed for type 2 diabetes susceptibility in up to 25 000 people (8148 with type 2 diabetes and 17687 control subjects) from two large independent Dutch cohorts and one Danish cohort. In addition, 340 Dutch subjects underwent a 2-h hyperglycaemic clamp to investigate insulin secretion. Since sexual dimorphic associations related to DRD2 polymorphisms have been previously reported, we also performed a gender-stratified analysis.

RESULTS

rs1800497 at the DRD2/ANKK1 locus was associated with a significantly increased risk for type 2 diabetes in women (odds ratio 1.14 (1.06-1.23); P = 4.1*10⁴) but not in men (odds ratio 1.00 (95% CI 0.93-1.07); P = 0.92) or the combined group. Although rs1800497 was not associated with insulin secretion, we did find another single nucleotide polymorphism in this locus, rs6275, to be associated with increased first-phase glucose-stimulated insulin secretion in women (P = 5.5*10⁴) but again not in men (P = 0.34).

CONCLUSION

The present data identify DRD2/ANKK1 as a potential sex-specific type 2 diabetes susceptibility gene.

Calorie restriction is a major determinant of the short-term metabolic effects of gastric bypass surgery in obese type 2 diabetic patients

OBJECTIVE

Roux-en-Y gastric bypass (RYGB) and restrictive weight loss interventions, such as gastric banding (GB) and very-low-calorie diets (VLCD) directly impact glucose metabolism, possibly by calorie restriction and/or altered secretion of gut hormones. We aimed to establish the direct endocrine and metabolic effects of RYGB compared to restrictive interventions in obese glucose-tolerant (NGT) subjects and subjects with type 2 diabetes (T2DM).

DESIGN

Controlled, nonrandomized observational trial.

PATIENTS AND MEASUREMENTS

Four groups of obese females received a mixed meal at baseline and 3 weeks after intervention; NGT-GB (n = 11), NGT-RYGB (n = 16), T2DM-RYGB (n = 15) and T2DM-VLCD (n = 12). Normal weight controls (n = 12) were studied once.

RESULTS

At baseline, all obese subjects were hyperinsulinemic. T2DM was associated with hyperglycaemia and decreased GLP-1 levels. RYGB and VLCD reduced glucose levels to a similar extent in T2DM, insulin levels decreased only after VLCD. Comparison of restrictive intervention vs RYGB showed a more pronounced decrease in glucose and insulin AUC after restriction. In NGT and T2DM subjects, RYGB increased GLP-1 and PYY levels and decreased ghrelin levels, whereas VLCD and GB only increased GIP levels.

CONCLUSIONS

These data indicate that deterioration of glucose metabolism in T2DM is associated with a decline of GLP-1 levels. Calorie restriction facilitates glucose metabolism and blunts hyperinsulinemia in obese (diabetic) humans. Additional duodenal exclusion through RYGB induces gut hormone release and hyperinsulinemia but does not improve postprandial glucose levels any further. Our data thus strongly suggest that calorie restriction underlies the short-term metabolic benefits of RYGB in obese T2DM patients.

Glucose and fat metabolism in narcolepsy and the effect of sodium oxybate: a hyperinsulinemic-euglycemic clamp study

INTRODUCTION

Narcolepsy is associated with obesity though it is uncertain whether this is caused by changes in glucose and fat metabolism. Therefore, we performed a detailed analysis of systemic energy homeostasis in narcolepsy patients, and additionally, investigated whether it was affected by three months of sodium oxybate (SXB) treatment.

METHODS

Nine hypocretin deficient patients with narcolepsy-cataplexy, and nine healthy sex, age, and BMI matched controls were enrolled. A hyperinsulinemic-euglycemic clamp combined with stable isotopes ([6,6-(2)H2]-glucose and [(2)H5]- glycerol) was performed at baseline. In seven patients a second study was performed after three months of SXB treatment.

RESULTS

Glucose disposal rate (GDR) per unit serum insulin was significantly higher in narcolepsy patients compared to matched controls (1.6 ± 0.2 vs. 1.1 ± 0.3 μmol/kgFFM/min/mU×L; P = 0.024), whereas β-cell function was similar (P = 0.50). Basal steady state glycerol appearance rate tended to be lower in narcolepsy patients (5.2 ± 0.4 vs. 7.5 ± 1.3 μmol/kgFM/min; P = 0.058), suggesting a lower rate of lipolysis. SXB treatment induced a trend in reduction of the GDR (1.4 ± 0.1 vs. 1.1 ± 0.2 μmol/kgFFM/min/mU×L; P = 0.063) and a reduction in endogenous glucose production (0.24 ± 0.03 vs. 0.16 ± 0.03 μmol/kgFFM/min/mU×L: P = 0.028) per unit serum insulin. After SXB treatment lipolysis increased (4.9 ± 0.4 vs. 6.5 ± 0.6 μmol/kgFM/min; P = 0.018), and body weight decreased in narcolepsy patients (99.2 ± 6.0 vs. 94.0 ± 5.4 kg; P = 0.044).

CONCLUSION

We show that narcolepsy patients are more insulin sensitive and may have a lower rate of lipolysis than matched controls. SXB stimulated lipolysis in narcolepsy patients, possibly accounting for the weight loss after treatment. While sodium oxybate tended to decrease systemic insulin sensitivity, it increased hepatic insulin sensitivity, suggesting tissue-specific effects.

Increased systemic and adipose tissue inflammation differentiates obese women with T2DM from obese women with normal glucose tolerance

INTRODUCTION

Obesity is strongly related to type-2 diabetes (T2DM), but there is a subset of obese individuals that remains relatively insulin sensitive and metabolically healthy. This study determined to what extent differences in metabolic health in obese women are associated with differences in adipose tissue and/or systemic inflammation.

METHODS

The subject group consisted of age comparable lean (n=12) and obese women either with T2DM (n=28) or normal glucose tolerance (NGT; n=26). Number of crown like structures (CLS) and adipocyte size were measured in subcutaneous and visceral adipose tissue of the obese women. Circulating cytokine and free fatty acid (FFA) levels, as well as number and activation status of peripheral leukocytes were determined.

RESULTS

Obese T2DM subjects showed higher circulating levels of IL-6, FFA and glycerol as compared to obese NGT subjects. Obese T2DM subjects had higher absolute numbers of peripheral leukocytes which were mainly due to an increase of T helper cells. Activation status of circulating cytotoxic T (CD8+CD25+) and B (CD19+CD38+) cells was significantly increased in obese NGT subjects as compared to lean but was not different between the two obese groups. Subcutaneous adipose tissue of obese T2DM subjects contained more CLS than adipose tissue of obese NGT subjects.

CONCLUSION

Obese T2DM subjects show higher FFA levels and adipose tissue macrophage infiltration in addition to higher levels of circulating IL-6 and numbers of CD4+ T cells than obese NGT subjects. Hence, obese T2DM subjects show a higher extent of inflammation at both the systemic and adipose tissue level.

Selenium Supplementation for Hashimoto's Thyroiditis: Summary of a Cochrane Systematic Review

Selenium supplementation in people with Hashimoto's thyroiditis might reduce antibody levels and result in a decreased dosage of levothyroxine (LT4) and may provide other beneficial effects (e.g. on mood and health-related quality of life). The aim of our systematic review was to assess the effects of selenium supplementation on Hashimoto's thyroiditis. We searched The Cochrane Library, MEDLINE, EMBASE and Web of Science for randomized controlled trials. Study selection, data extraction, assessment of risk of bias and analyses were carried out by two independent review authors. We assessed the quality of the evidence of included studies using GRADE. Four studies rated at unclear to high risk of bias comprising 463 participants were included. One study at high risk of bias showed statistically significant improvement in subjective well-being with sodium selenite 200 μg plus titrated LT4 compared with placebo plus titrated LT4 (RR 4.67, 95% CI 1.61-13.50). Selenomethionine 200 μg as a single treatment or combined with LT4 reduced the serum levels of anti-thyroid peroxidase antibodies compared with placebo (or placebo plus LT4) in three studies (p < 0.001). Although the changes from baseline were statistically significant in these three studies, their clinical relevance is unclear. In conclusion, the results of these four studies, assessed at unclear to high risk of bias, show that evidence to support or refute the efficacy of selenium supplementation in people with Hashimoto's thyroiditis is incomplete and not reliable to help inform clinical decision making.

Thyrotropin secretion in healthy subjects is robust and independent of age and gender, and only weakly dependent on body mass index

CONTEXT

Studies of the influence of sex, age, and body weight on TSH secretion are not unanimous. Most reports are based on a single TSH measurement; studies using frequent blood sampling are scarce and include a limited number of selected subjects.

OBJECTIVE

The goal was to investigate TSH dynamics in 117 healthy adults.

METHODS

TSH was measured by a sensitive immunofluorometric assay. Secretion parameters were quantified by automated deconvolution, approximate entropy [ApEn], spikiness, and diurnal properties.

RESULTS

Mean age was 43 years (range, 22-77 y). Mean body mass index (BMI) was 26.8 kg/m(2) (range, 18.3-39.4 kg/m(2)). Daily TSH secretion was 45.4 mU/L (range, 8.0-207 mU/L). There were no sex differences in secretion parameters, including pulse frequency; basal, pulsatile, and total secretion; pulse mode; half life; pulse regularity; ApEn; spikiness; and nycthemeral properties. BMI was positively related to basal secretion. Total secretion correlated negatively with free T₄ (R = 0.225; P = .018). The onset of the nocturnal surge was delayed by increasing BMI and advanced by increasing age. ApEn and spikiness correlated positively with age, especially in men. The 9 am sample correlated strongly with the total 24-hour secretion, explaining two-thirds of the variability.

CONCLUSION

This study shows that the 24-hour TSH secretion in healthy volunteers is stable and robust and not influenced by sex, BMI, and age. ApEn in the elderly, especially men, is increased, pointing to a less tight feedback control. Furthermore, aging is associated with advance shifting of the TSH rhythm, which is a phenomenon also observed in other biological rhythms.

A 5-day high-fat, high-calorie diet impairs insulin sensitivity in healthy, young South Asian men but not in Caucasian men

South Asians (SAs) develop type 2 diabetes at a younger age and lower BMI compared with Caucasians (Cs). The underlying cause is still poorly understood but might result from an innate inability to adapt to the Westernized diet. This study aimed to compare the metabolic adaptation to a high-fat, high-calorie (HFHC) diet between both ethnicities. Twelve healthy, young lean male SAs and 12 matched Cs underwent a two-step hyperinsulinemic-euglycemic clamp with skeletal muscle biopsies and indirect calorimetry before and after a 5-day HFHC diet. Hepatic triglyceride content (HTG) and abdominal fat distribution were assessed using magnetic resonance imaging and spectroscopy. At baseline, SAs had higher insulin clamp levels than Cs, indicating reduced insulin clearance rate. Despite the higher insulin levels, endogenous glucose production was comparable between groups, suggesting lower hepatic insulin sensitivity in SAs. Furthermore, a 5-day HFHC diet decreased the insulin-stimulated (nonoxidative) glucose disposal rate only in SA. In skeletal muscle, no significant differences were found between groups in insulin/mammalian target of rapamycin signaling, metabolic gene expression, and mitochondrial respiratory chain content. Furthermore, no differences in (mobilization of) HTG and abdominal fat were detected. We conclude that HFHC feeding rapidly induces insulin resistance only in SAs. Thus, distinct adaptation to Western food may partly explain their propensity to develop type 2 diabetes.

Abstract P4-16-12: CARE: A pilot study of the effects of short-term fasting on tolerance to (neo) adjuvant chemotherapy in breast cancer patients

Background:

Preclinical evidence shows that short-term fasting (STS) protects normal cells and makes cancer cells more vulnerable to chemotherapy. This pilot study examines the feasibility and the effects of STS on tolerance to chemotherapy in patients with breast cancer.

Patients and methods:

Eligible patients had histologically confirmed, HER2-negative, early stage breast cancer and adequate bone marrow, liver and renal function. Women receiving (neo) adjuvant TAC courses (docetaxel/adriamycin/cyclophosphamide; day 1, q 3 weeks with G-CSF support at day 2) were randomized to fast 24 hours before and 24 hours after start of chemotherapy or to eat according to the guideline for healthy nutrition. The primary endpoint of the study was to compare neutrophil count after therapy. Secondary endpoints were side effects of chemotherapy, other hematologic counts and chemotherapy-induced DNA damage in leukocytes.

Results:

A total of 13 patients were included of which 7 patients fasted for 48 hours around the chemotherapy infusion (arm A) and 6 patients had a normal diet according to healthy nutrition guidelines (arm B). The median age was 52 years versus 53 years, BMI was 25.5 kg/m2 versus 22.9 kg/m2 and stage III was 43% versus 17% of patients in arms A and B, respectively. Patients were generally motivated to fast and the fasting was well tolerated. Plasma glucose levels were significant lower in fasting patients compared to controls. However, other metabolic parameters showed no significant difference. Fasting did not result in significant differences in neutrophil count or side effects of chemotherapy. Hemoglobin levels and erythrocyte counts after therapy were significantly higher in patients who fasted. Leukocytes of the patients which were isolated at various time points during therapy will soon be analysed for chemotherapy-induced DNA damage and presented at San Antonio.

Conclusion:

This is the first study evaluating the feasibility of 48 hours STS and its impact on side effects of chemotherapy in a homogeneous group of cancer patients. STS was well tolerated and had a beneficial effect on hemoglobin level, but not on experienced side effects. DNA analysis will follow. Larger studies are required to produce more insight into the possible benefits of STS during chemotherapy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-16-12.

Abstract OT3-1-03: DIRECT: A phase II/III randomized trial with dietary restriction as an adjunct to neoadjuvant chemotherapy for HER2-negative breast cancer

Background:

Preclinical evidence shows that short-term fasting protects normal cells, while cancer cells are sensitized to chemotherapy. Furthermore, a specifically designed very low calorie, low amino acid substitution diet (“Fasting Mimicking Diet”, FMD) has similar effects on chemotherapy as short-term fasting. This trial evaluates the impact of FMD on tolerance to and efficacy of neoadjuvant chemotherapy in women with HER2-negative early breast cancer.

Trial design:

DIRECT is a Dutch, randomized, open-label multicenter phase II/III trial. Women receiving neoadjuvant TAC courses (docetaxel/adriamycin/cyclophosphamide; day 1, q 3 weeks with G-CSF support at day 2) will be randomized with or without FMD for 3 days prior to and the day of chemotherapy and 3 days prior to surgery.

Eligibility criteria:

Eligible women are WHO 0-2, age ≥18 years, HER2-negative, stage II or III breast cancer and adequate bone marrow, liver and renal function, BMI &gt; 19kg/m2 and absence of diabetes mellitus.

Study endpoints:

The primary endpoints are grade III/IV toxicity (phase II) and the pathologic complete response rate (pCR) (phase III). Secondary endpoints are grade I/II toxicity, metabolic and inflammatory response to chemotherapy, DNA damage, apoptosis, immunology and nutrient sensing pathways in the tumor, biomarkers as single nucleotide polymorphisms, Ki67 and tumor stroma/ratio, patient's quality of life and (disease free) survival. Optional side studies include chemotherapy-induced DNA damage and nutrient sensing pathways in leukocytes and proteomics.

Statistical Methods:

Using a 5% significance level based on the two-sided Fisher's exact test with a power of 80%, 128 patients (64/arm) will be enrolled to show a 50% decrease of grade III/IV adverse events in the experimental arm (phase II) and 250 patients (125/arm) are needed to show an improvement of the pCR rate from 18% to 36% (phase III).

Target accrual:

Recruitment will start in September 2013. The expected end of accrual of 250 patients from multiple centers in the Netherlands will be the last quarter of 2015.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT3-1-03.

Obesity is associated with an altered autonomic nervous system response to nutrient restriction

OBJECTIVE

Heart rate variability (HRV) reflects the balance of activities of sympathetic and parasympathetic components of the autonomic nervous system. We compared HRV parameters in response to a prolonged fast in obese versus normal weight humans. In addition, the effect of weight-loss was evaluated in obese individuals.

DESIGN

Intervention study.

PATIENTS

The study subjects included 14 nondiabetic obese (12 females/2 males, aged 30 ± 3 years, Body Mass Index (BMI) 35·2 ± 1·2 kg/m(2) ) and 12 lean subjects (10 females/2 males, aged 27 ± 3 years, BMI 23·3 ± 0·5 kg/m(2) ).

MEASUREMENTS

HRV was examined 75 min after standardized breakfast and after a 48-h fast in 14 nondiabetic obese and 12 lean subjects. The postprandial measurement was repeated in 12 obese subjects after weight-loss.

RESULTS

In lean subjects, fasting decreased high-frequency (HF) power by 43% (P < 0·05) and decreased low-frequency (LF) power by 37% (P = 0·1), leaving the LF/HF ratio unchanged (P = 0·7). In the obese group, autonomic nervous system tone shifted to sympathetic dominance as the LF/HF increased from 0·61 to 1·14 (P = 0·03). After an average weight-loss of 13·8 kg in obese subjects, a trend for sympathetic dominance was found; the LF/HF ratio increased by 56% (P = 0·06).

CONCLUSION

Our data show that a 48-h fast leaves autonomic nervous system balance unaltered in lean subjects. In contrast, a 48-h fast, as well as weight-loss, induces sympathetic dominance in obese humans.

Autonomic nervous system activity in diabetic and healthy obese female subjects and the effect of distinct weight loss strategies

OBJECTIVE

Obesity and type 2 diabetes mellitus (T2DM) are reported to be associated with relative overactivity of the sympathetic nervous system (SNS), which is reversible by weight loss. However, direct effects of weight loss by calorie restriction vs Roux-en-Y gastric bypass (RYGB) on SNS overactivity were not studied in parallel. This study compared the effects of RYGB vs restrictive weight loss in obese patients with normal glucose tolerance (NGT) and with T2DM on SNS function as measured by heart rate variability (HRV).

DESIGN AND METHODS

Lean (n=12), obese NGT (n=27) and T2DM (n=27) subjects were included in this study. Weight reduction in NGT subjects was achieved by gastric banding (GB) or RYGB and in T2DM subjects by RYGB or high-protein very-low-calorie diet (VLCD). HRV analysis was performed and blood samples were taken at baseline, 3 weeks and 3 months after intervention.

RESULTS

At baseline, T2DM subjects showed SNS overactivity and NGT subjects showed similar, but non-significant, findings when compared with lean controls. Weight loss after 3 weeks was comparable in all treatment groups, whereas after 3 months, weight loss was most in VLCD and RYGB subjects. RYGB and VLCD treatment reduced SNS activity within 3 weeks in T2DM patients. After 3 months, restoration to normal autonomic nervous system activity was evident for all groups, except for the NGT-GB group.

CONCLUSION

We can conclude that SNS overactivity is more pronounced in obese T2DM subjects when compared with NGT subjects. Reduction of SNS overactivity coincides with weight loss with the time-course of reduction dependent on the type of intervention. Surgery or caloric restriction may transiently induce SNS overactivity but do not prevent a direct restoration of sympathovagal balance.

Roux-en-Y gastric bypass and calorie restriction induce comparable time-dependent effects on thyroid hormone function tests in obese female subjects

OBJECTIVE

Obesity and weight loss influence thyroid hormone physiology. The effects of weight loss by calorie restriction vs Roux-en-Y gastric bypass (RYGB) in obese subjects have not been studied in parallel. We hypothesized that differences in transient systemic inflammation and catabolic state between the intervention types could lead to differential effects on thyroid hormone physiology.

DESIGN AND METHODS

We recruited 12 lean and 27 obese females with normal fasting glucose (normal glucose tolerant (NGT)) and 27 obese females with type 2 diabetes mellitus (T2DM) for this study. Weight loss was achieved by restrictive treatment (gastric banding or high-protein-low-calorie diet) or by RYGB. Fasting serum leptin, TSH, triiodothyronine (T₃), reverse T₃ (rT₃), and free thyroxine (fT₄) concentrations were measured at baseline and 3 weeks and 3 months after the start of the interventions.

RESULTS

Obesity was associated with higher TSH, T₃, and rT₃ levels and normal fT₄ levels in all the subjects when compared with the controls. After 3 weeks, calorie restriction and RYGB induced a decline in TSH levels and a rise in rT₃ and fT₄ levels. The increase in rT₃ levels correlated with serum interleukin 8 (IL8) and IL6 levels. After 3 months, fT₄ and rT₃ levels returned to baseline levels, whereas TSH and T₃ levels were persistently decreased when compared with baseline levels. No differences in the effects on thyroid hormone parameters between the interventions or between NGT and T2DM subjects were observed at any time point.

CONCLUSIONS

In summary, weight loss directly influences thyroid hormone regulation, independently of the weight loss strategy used. The effects may be explained by a combination of decreased leptin levels and transient changes in peripheral thyroid hormone metabolism.

Plasma total ghrelin and leptin levels in human narcolepsy and matched healthy controls: basal concentrations and response to sodium oxybate

STUDY OBJECTIVES

Narcolepsy is caused by a selective loss of hypocretin neurons and is associated with obesity. Ghrelin and leptin interact with hypocretin neurons to influence energy homeostasis. Here, we evaluated whether human hypocretin deficiency, or the narcolepsy therapeutic agent sodium oxybate, alter the levels of these hormones.

METHODS

Eight male, medication free, hypocretin deficient, narcolepsy with cataplexy patients, and 8 healthy controls matched for age, sex, body mass index (BMI), waisttohip ratio, and body fat percentage were assessed. Blood samples of total ghrelin and leptin were collected over 24 hours at 60 and 20-min intervals, respectively, during 2 study occasions: baseline, and during the last night of 5 consecutive nights of sodium oxybate administration (2 × 3.0 g/night).

RESULTS

At baseline, mean 24-h total ghrelin (936 ± 142 vs. 949 ± 175 pg/mL, p = 0.873) and leptin (115 ± 5.0 vs. 79.0 ± 32 mg/L, p = 0.18) levels were not different between hypocretin deficient narcolepsy patients and controls. Furthermore, sodium oxybate did not significantly affect the plasma concentration of either one of these hormones.

CONCLUSIONS

The increased BMI of narcolepsy patients is unlikely to be mediated by hypocretin deficiency-mediated alterations in total ghrelin or leptin levels. Thus, the effects of these hormones on hypocretin neurons may be mainly unidirectional. Although sodium oxybate may influence body weight, the underlying mechanism is unlikely to involve changes in total ghrelin or leptin secretion.

Adipocytes modulate the phenotype of human macrophages through secreted lipids

Previous studies have shown accumulation and an enhanced proinflammatory profile of macrophages in adipose tissue of obese mice, indicating the presence of an interaction between adipocytes and macrophages in this tissue. However, the consequences of this interaction in humans are yet incompletely understood. In this study, we explored the modulating effects of adipocytes on the phenotype of macrophages in humans and studied the possible molecular pathways involved. Adipocyte-conditioned media (ACM) treatment of macrophages for 48 h strongly reduced the LPS-induced IL-12p40 secretion by macrophages, whereas the production of TNF-α and other cytokines remained largely unaffected. This effect was independent of the source of adipocytes. Interestingly, the level of inhibition correlated directly with body mass index (BMI) of the adipocyte donor. Because adipocytes release many different cytokines, adipokines, and lipids, we have separated the protein and lipid fractions of ACM, to obtain insight into the molecular nature of the soluble mediators underlying the observed effect. These experiments revealed that the inhibitory effect resided predominantly in the lipid fraction. Further studies revealed that PGE2 and linoleic and oleic acid were potent inhibitors of IL-12p40 secretion. Interestingly, concentrations of these ACM-derived lipids increased with increase in BMI of the adipocyte donor, suggesting that they could mediate the BMI-dependent effects of ACM. To our knowledge, these results provide first evidence that obesity-related changes in adipose tissue macrophage phenotype could be mediated by adipocyte-derived lipids in humans. Intriguingly, these changes appear to be different from those in murine obesity.

Selenium supplementation for Hashimoto's thyroiditis

BACKGROUND

Hashimoto's thyroiditis is a common auto-immune disorder. The most common presenting symptoms may include anxiety, negative mood, depression, dry skin, cold intolerance, puffy eyes, muscle cramps and fatigue, deep voice, constipation, slow thinking and poor memory. Clinical manifestations of the disease are defined primarily by low levels of thyroid hormones; therefore it is treated by hormone replacement therapy, which usually consists of levothyroxine (LT4). Selenium might reduce antibody levels and result in a decreased dosage of LT4 and may provide other beneficial effects (e.g. on mood and health-related quality of life).

OBJECTIVES

To assess the effects of selenium supplementation on Hashimoto's thyroiditis.

SEARCH METHODS

We searched the following databases up to 2 October 2012: CENTRAL in The Cochrane Library (2012, Issue 10), MEDLINE, EMBASE, and Web of Science; we also screened reference lists of included studies and searched several online trial registries for ongoing trials (5 November 2012).

SELECTION CRITERIA

Randomised controlled clinical trials that assessed the effects of selenium supplementation for adults diagnosed with Hashimoto's thyroiditis.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction, assessment of risk of bias, and analyses were carried out by two independent review authors. We assessed the quality of the evidence of included studies using GRADE. We were unable to conduct a meta-analysis because clinical heterogeneity between interventions that were investigated is substantial.

MAIN RESULTS

Four studies at unclear to high risk of bias comprising 463 participants were included. The mean study duration was 7.5 months (range 3 to 18 months). One of our primary outcomes－'change from baseline in health related quality of life'－and two of our secondary outcomes－'change from baseline in LT4 replacement dosage at end of the study' and 'economic costs'－were not assessed in any of the studies. One study at high risk of bias showed statistically significant improvement in subjective well-being with sodium selenite 200 μg plus titrated LT4 compared with placebo plus titrated LT4 (relative risk (RR) 4.67, 95% confidence interval (CI) 1.61 to 13.50; P = 0.004; 36 participants; number needed to treat (NNT) = 2 (95% CI 2 to 3)).Selenomethionine 200 μg reduced the serum levels of anti-thyroid peroxidase antibodies compared with placebo in two studies (mean difference (MD) -917 U/mL, 95% CI -1056 to -778; P < 0.001; 85 participants) and (MD -345 IU/mL, 95% CI -359 to -331; P < 0.001; 169 participants). Pooling of the studies was not feasible due to marked clinical heterogeneity (I(2) = 99%). In a further comparison within the first study where selenomethionine was combined with LT4 the reduction in TPO antibodies was even more noticeable (MD -1508 U/mL, 95% CI -1671 to -1345; P < 0.001; 86 participants). In a third study, where LT4 was added to both intervention arms, a reduction in serum levels of anti-thyroid peroxidase antibodies favoured the selenomethionine arm as well (MD -235 IU/mL, 95% CI -374 to -95; P = 0.001; 88 participants). Although the changes from baseline were statistically significant in these three studies, their clinical relevance is unclear. Serum antibodies were not statistically significantly affected in the study comparing sodium selenite 200 μg plus titrated LT4 with placebo plus titrated LT4 (MD -25, 95% CI -181 to 131; P = 0.75; 36 participants).Adverse events were reported in two studies (1 of 85 and 1 of 88 participants, respectively). Selenium supplementation did not appear to have a statistically significant impact on the incidence of adverse events (RR 2.93, 95% CI 0.12 to 70.00; and RR 2.63, 95% CI 0.11 to 62.95).

AUTHORS' CONCLUSIONS

Results of these four studies show that evidence to support or refute the efficacy of selenium supplementation in people with Hashimoto's thyroiditis is incomplete. The current level of evidence for the efficacy of selenium supplementation in the management of people with Hashimoto's thyroiditis is based on four randomised controlled trials assessed at unclear to high risk of bias; this does not at present allow confident decision making about the use of selenium supplementation for Hashimoto's thyroiditis. This review highlights the need for randomised placebo-controlled trials to evaluate the effects of selenium in people with Hashimoto's thyroiditis and can ultimately provide reliable evidence to help inform clinical decision making.

Effects of prolonged fasting on AMPK signaling, gene expression, and mitochondrial respiratory chain content in skeletal muscle from lean and obese individuals

Obesity in humans is often associated with metabolic inflexibility, but the underlying molecular mechanisms remain incompletely understood. The aim of the present study was to investigate how adaptation to prolonged fasting affects energy/nutrient-sensing pathways and metabolic gene expression in skeletal muscle from lean and obese individuals. Twelve lean and 14 nondiabetic obese subjects were fasted for 48 h. Whole body glucose/lipid oxidation rates were determined by indirect calorimetry, and blood and skeletal muscle biopsies were collected and analyzed. In response to fasting, body weight loss was similar in both groups, but the decrease in plasma insulin and leptin and the concomitant increase in growth hormone were significantly attenuated in obese subjects. The fasting-induced shift from glucose toward lipid oxidation was also severely blunted. At the molecular level, the expression of insulin receptor-β (IRβ) was lower in skeletal muscle from obese subjects at baseline, whereas the fasting-induced reductions in insulin signaling were similar in both groups. The protein expression of mitochondrial respiratory chain components, although not modified by fasting, was significantly reduced in obese subjects. Some minor differences in metabolic gene expression were observed at baseline and in response to fasting. Surprisingly, fasting reduced AMPK activity in lean but not in obese subjects, whereas the expression of AMPK subunits was not affected. We conclude that whole body metabolic inflexibility in response to prolonged fasting in obese humans is associated with lower skeletal muscle IRβ and mitochondrial respiratory chain content as well as a blunted decline of AMPK activity.

Ambulant 24-h glucose rhythms mark calendar and biological age in apparently healthy individuals

Glucose metabolism marks health and disease and is causally inferred in the aging process. Ambulant continuous glucose monitoring provides 24-h glucose rhythms under daily life conditions. We aimed to describe ambulant 24-h glucose rhythms measured under daily life condition in relation to calendar and biological age in apparently healthy individuals. In the general population and families with propensity for longevity, we studied parameters from 24-h glucose rhythms; glucose levels; and its variability, obtained by continuous glucose monitoring. Participants were 21 young (aged 22-37 years), 37 middle-aged (aged 44-72 years) individuals from the general population, and 26 middle-aged (aged 52-74 years) individuals with propensity for longevity. All were free of diabetes. Compared with young individuals, middle-aged individuals from the general population had higher mean glucose levels (5.3 vs. 4.7 mmol L(-1) , P < 0.001), both diurnally (P < 0.001) and nocturnally (P = 0.002). Glucose variability was higher in the middle-aged compared with the young (standard deviation 0.70 vs. 0.57 mmol L(-1) , P = 0.025). Compared with middle-aged individuals from the general population, middle-aged individuals with propensity for longevity had lower overall mean glucose levels (5.2 vs. 5.4 mmol L(-1) , P = 0.047), which were more different nocturnally (4.8 vs. 5.2 mmol L(-1) , P = 0.003) than diurnally (5.3 vs. 5.5 mmol L(-1) , P = 0.14). There were no differences in glucose variability between these groups. Results were independent of body mass index. Among individuals without diabetes, we observed significantly different 24-h glucose rhythms depending on calendar and biological age.

Phase difference between serum prolactin and cortisol rhythms is related to body mass index in humans

BACKGROUND

Prolactin (PRL) has many effects in animals and man. For example, it regulates fat mass in fish, birds, and mammals. In particular, the timing of the serum PRL acrophase in relation to the light-dark cycle or to serum cortisol in constant light conditions determines whether the fat mass increases or decreases, as part of the adaptation to seasons. The role of PRL in this respect has been less well studied in man.

HYPOTHESIS

We hypothesized that the timing of the PRL acrophase (time point of peak amplitude of the rhythm) with respect to that of cortisol may be correlated with fat mass [or body mass index (BMI) as proxy] in the human, as observed in animals.

SUBJECTS

Seventy-four subjects were available [mean age, 43 (22-77) yr; mean BMI, 26.8 (18.7-38.4) kg/m(2)].

MEASURES

Immunofluorometric PRL assay and cortisol RIA of 10-min blood samples collected for 24 h were followed by cosinor analysis for the estimation of the acrophase.

RESULTS

The time difference between the cortisol and PRL acrophases was positively correlated with BMI (P = 0.002), but not with sex, age, or season.

CONCLUSION

In various species, a wide gap between the serum cortisol acrophase and that of PRL leads to fat storage. Our finding is consistent with this observation, although we used BMI as proxy. If an advance shift of the PRL acrophase in relation to that of cortisol is indeed responsible for increased fat mass in man, manipulating the PRL phase may offer an alternative means to treat obesity.