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Open access

Ahmet Uçar, Nurçin Saka, Firdevs Baş, Nihal Hatipoğlu, Rüveyde Bundak, and Feyza Darendeliler

Context

An association between low birth weight, insulin resistance (IR), dyslipidemia, and atherogenesis has been shown in girls with precocious adrenarche (PA).

Objective

To evaluate whether girls with PA born appropriate for gestational age (AGA) have increased risk for metabolic complications at initial evaluation.

Design/methods

We conducted a cross-sectional study on 69 AGA born girls with PA (mean (±s.d.) age 7.1±1 years) and 45 body mass index (BMI)- and waist circumference (WC)-matched prepubertal peers born AGA (mean (±s.d.) 7.5±1.9 years). A standard 2-h oral glucose tolerance test with insulin sampling was performed. Fasting plasma lipids and high-sensitivity C-reactive protein were analyzed, and blood pressure was recorded. Insulin sensitivity (IS) index (ISIcomp), homeostasis model assessment of IR, and atherogenic index (AI) (triglycerides/high-density lipoprotein cholesterol) were calculated.

Setting

The study was performed at University Hospital.

Results

AI was significantly lower in girls with PA than in controls (P<0.001), and it was correlated with BMI SDS (r=0.44, P=0.001) and WC (r=0.39, P=0.001). The significant correlation of AI with ISIcomp (r=−0.38, P=0.001) disappeared after correcting for BMI (r=−0.185, P=0.16). Multivariate regression analysis revealed that DHEAS was the only significant parameter influencing AI in girls with born AGA (R 2=0.475 β=−0.018, P=0.0001).

Conclusions

Metabolic screening in prepubertal AGA born girls with PA may yield favorable lipid profiles. AI in girls with PA is increased in relation to decreasing IS and increasing BMI and WC. DHEAS seems to have the most significant effect on AI.

Open access

Annieke C G van Baar, Andrei Prodan, Camilla D Wahlgren, Steen S Poulsen, Filip K Knop, Albert K Groen, Jacques J Bergman, Max Nieuwdorp, and Evgeni Levin

Background

Enteroendocrine cells are essential for the regulation of glucose metabolism, but it is unknown whether they are associated with clinical features of metabolic syndrome (MetS) and fasting plasma metabolites.

Objective

We aimed to identify fasting plasma metabolites that associate with duodenal L cell, K cell and delta cell densities in subjects with MetS with ranging levels of insulin resistance.

Research design and methods

In this cross-sectional study, we evaluated L, K and delta cell density in duodenal biopsies from treatment-naïve males with MetS using machine-learning methodology.

Results

We identified specific clinical biomarkers and plasma metabolites associated with L cell and delta cell density. L cell density was associated with increased plasma metabolite levels including symmetrical dimethylarginine, 3-aminoisobutyric acid, kynurenine and glycine. In turn, these L cell-linked fasting plasma metabolites correlated with clinical features of MetS.

Conclusions

Our results indicate a link between duodenal L cells, plasma metabolites and clinical characteristics of MetS. We conclude that duodenal L cells associate with plasma metabolites that have been implicated in human glucose metabolism homeostasis. Disentangling the causal relation between L cells and these metabolites might help to improve the (small intestinal-driven) pathophysiology behind insulin resistance in human obesity.

Open access

Kaisa K Ivaska, Maikki K Heliövaara, Pertti Ebeling, Marco Bucci, Ville Huovinen, H Kalervo Väänänen, Pirjo Nuutila, and Heikki A Koistinen

Insulin signaling in bone-forming osteoblasts stimulates bone formation and promotes the release of osteocalcin (OC) in mice. Only a few studies have assessed the direct effect of insulin on bone metabolism in humans. Here, we studied markers of bone metabolism in response to acute hyperinsulinemia in men and women. Thirty-three subjects from three separate cohorts (n=8, n=12 and n=13) participated in a euglycaemic hyperinsulinemic clamp study. Blood samples were collected before and at the end of infusions to determine the markers of bone formation (PINP, total OC, uncarboxylated form of OC (ucOC)) and resorption (CTX, TRAcP5b). During 4 h insulin infusion (40 mU/m2 per min, low insulin), CTX level decreased by 11% (P<0.05). High insulin infusion rate (72 mU/m2 per min) for 4 h resulted in more pronounced decrease (−32%, P<0.01) whereas shorter insulin exposure (40 mU/m2 per min for 2 h) had no effect (P=0.61). Markers of osteoblast activity remained unchanged during 4 h insulin, but the ratio of uncarboxylated-to-total OC decreased in response to insulin (P<0.05 and P<0.01 for low and high insulin for 4 h respectively). During 2 h low insulin infusion, both total OC and ucOC decreased significantly (P<0.01 for both). In conclusion, insulin decreases bone resorption and circulating levels of total OC and ucOC. Insulin has direct effects on bone metabolism in humans and changes in the circulating levels of bone markers can be seen within a few hours after administration of insulin.

Open access

Nadia Sawicka-Gutaj, Ariadna Zybek-Kocik, Michał Kloska, Paulina Ziółkowska, Agata Czarnywojtek, Jerzy Sowiński, Dorota Mańkowska-Wierzbicka, and Marek Ruchała

Dysregulation of thyroid function has known impact on body metabolism, however, data regarding metabolic outcome after restoration of thyroid function is limited. Therefore, the aim of the study was to investigate the effect of restoration of euthyroidism on serum visfatin, and its associations with insulin resistance and body composition. This is an observational study with consecutive enrollment. Forty-nine hyperthyroid (median age of 34 years) and 44 hypothyroid women (median age of 46 years) completed the study. Laboratory parameters and body composition analysis were assessed before and after the therapy. In the hyperthyroid group, visfatin concentrations increased (P < 0.0001), while glucose concentrations decreased (P < 0.0001). Total body mass and fat mass in the trunk and limbs significantly increased during the treatment. In the hypothyroid group, significant weight loss resulted from decrease of fat and muscle masses in trunk and limbs. Visfatin serum concentrations positively correlated with total fat mass (r = 0.19, P = 0.01) and insulin concentrations (r = 0.17, P = 0.018). In conclusion, restoration of thyroid function is not associated with beneficial changes in body composition, especially among hyperthyroid females.

Open access

Siphiwe N Dlamini, Zané Lombard, Lisa K Micklesfield, Nigel Crowther, Shane A Norris, Tracy Snyman, Andrew A Crawford, Brian R Walker, and Julia H Goedecke

Circulating glucocorticoids are associated with metabolic syndrome and related cardiometabolic risk factors in non-Africans. This study investigated these associations in Africans, whose metabolic phenotype reportedly differs from Europeans. Adiposity, blood pressure, glycaemia, insulin resistance, and lipid profile, were measured in 316 African men and 788 African women living in Soweto, Johannesburg. The 2009 harmonized criteria were used to define metabolic syndrome. Serum glucocorticoids were measured using liquid chromatography-mass spectrometry. Cortisol was associated with greater odds presenting with metabolic syndrome (odds ratio (95% CI) =1.50 (1.04, 2.17) and higher systolic (beta coefficient, β (95% CI) =0.04 (0.01, 0.08)) and diastolic (0.05 (0.02, 0.09)) blood pressure, but higher HDL (0.10 (0.02, 0.19)) and lower LDL (−0.14 (−0.24, −0.03)) cholesterol concentrations, in the combined sample of men and women. In contrast, corticosterone was only associated with higher insulin sensitivity (Matsuda index; 0.22 (0.03, 0.41)), but this was not independent of BMI. Sex-specific associations were observed, such that both cortisol and corticosterone were associated with higher fasting glucose (standardized β (95% CI): 0.24 (0.12, 0.36) for cortisol and 0.12 (0.01, 0.23) for corticosterone) and HbA1c (0.13 (0.01, 0.25) for cortisol and 0.12 (0.01, 0.24) for corticosterone) in men only, but lower HbA1c (0.10 (−0.20, −0.01) for cortisol and −0.09 (−0.18, −0.03) for corticosterone) in women only. Our study reports for the first time that associations between circulating glucocorticoid concentrations and key cardiometabolic risk factors exhibit both glucocorticoid- and sex-specificity in Africans.

Open access

Nikolaj Rittig, Mads Svart, Niels Jessen, Niels Møller, Holger J Møller, and Henning Grønbæk

Background

Macrophage activation determined by levels of soluble sCD163 is associated with obesity, insulin resistance, diabetes mellitus type 2 (DM2) and non-alcoholic fatty liver disease (NAFLD). This suggests that macrophage activation is involved in the pathogenesis of conditions is characterised by adaptions in the lipid metabolism. Since sCD163 is shed to serum by inflammatory signals including lipopolysaccharides (LPS, endotoxin), we investigated sCD163 and correlations with lipid metabolism following LPS exposure.

Methods

Eight healthy male subjects were investigated on two separate occasions: (i) following an LPS exposure and (ii) following saline exposure. Each study day consisted of a four-hour non-insulin-stimulated period followed by a two-hour hyperinsulinemic euglycemic clamp period. A 3H-palmitate tracer was used to calculate the rate of appearance (Rapalmitate). Blood samples were consecutively obtained throughout each study day. Abdominal subcutaneous adipose tissue was obtained for western blotting.

Results

We observed a significant two-fold increase in plasma sCD163 levels following LPS exposure (P < 0.001), and sCD163 concentrations correlated positively with the plasma concentration of free fatty acids, Rapalmitate, lipid oxidation rates and phosphorylation of the hormone-sensitive lipase at serine 660 in adipose tissue (P < 0.05, all). Furthermore, sCD163 concentrations correlated positively with plasma concentrations of cortisol, glucagon, tumour necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10 (P < 0.05, all).

Conclusion

We observed a strong correlation between sCD163 and stimulation of lipolysis and fat oxidation following LPS exposure. These findings support preexisting theory that inflammation and macrophage activation play a significant role in lipid metabolic adaptions under conditions such as obesity, DM2 and NAFLD.

Open access

Yusaku Mori, Eunhyoung Ko, Rudolf Furrer, Linda C Qu, Stuart C Wiber, I George Fantus, Mario Thevis, Alan Medline, and Adria Giacca

It is not fully clarified whether insulin glargine, an analogue with a high affinity for insulin-like growth factor-1 receptor (IGF-1R), increases the risk for cancers that abundantly express IGF-1R such as breast cancer or some types of breast cancer. To gain insight into this issue, female Sprague–Dawley rats fed a high-fat diet were given the carcinogen N-methyl-N-nitrosourea and randomly assigned to vehicle (control), NPH (unmodified human insulin), glargine or detemir (n = 30 per treatment). Insulins were given subcutaneously (15 U/kg/day) 5 days a week. Mammary tumours were counted twice weekly, and after 6 weeks of treatment, extracted for analysis. None of the insulin-treated groups had increased mammary tumour incidence at any time compared with control. At 6 weeks, tumour multiplicity was increased with NPH or glargine (P < 0.05) and tended to be increased with detemir (P = 0.2); however, there was no difference among insulins (number of tumours per rat: control = 0.8 ± 0.1, NPH = 1.8 ± 0.3, glargine = 1.5 ± 0.4, detemir = 1.4 ± 0.4; number of tumours per tumour-bearing rat: control = 1.3 ± 0.1, NPH = 2.2 ± 0.4, glargine = 2.7 ± 0.5, detemir = 2.3 ± 0.5). IGF-1R expression in tumours was lower than that in Michigan Cancer Foundation-7 (MCF-7) cells, a cell line that shows greater proliferation with glargine than unmodified insulin. In rats, glargine was rapidly metabolised to M1 that does not have greater affinity for IGF-1R. In conclusion, in this model of oestrogen-dependent breast cancer in insulin-resistant rats, insulin and insulin analogues increased tumour multiplicity with no difference between insulin types.

Open access

Chao Xu, Xiang-Fei Li, Hong-Yan Tian, Hua-Juan Shi, Ding-Dong Zhang, Kenneth Prudence Abasubong, and Wen-Bin Liu

After a 12-week feeding trial, the glucose tolerance test was performed in Megalobrama amblycephala to evaluate the effects of metformin on the metabolic responses of glycolipids. Plasma insulin peaked at 2 h, then decreased to the basal value at 8–12 h post-injection. Plasma triglyceride levels and liver glycogen contents of the control group was decreased significantly during the first 2 and 1 h, respectively. Then, they returned to basal values at 12 h. During the whole sampling period, the high-carbohydrate groups had significantly higher levels of plasma metabolites and liver glycogen than those of the control group, and metformin supplementation enhanced these changes (except insulin levels). Glucose administration lowered the transcriptions of ampk α1, ampk α2, pepck, g6pase, fbpase, cpt IA and aco, the phosphorylation of Ampk α and the activities of the gluconeogenic enzymes during the first 2–4 h, while the opposite was true of glut 2, gs, gk, pk, accα and fas. High-carbohydrate diets significantly increased the transcriptions of ampk α1, ampk α2, glut 2, gs, gk, pk, accα and fas, the phosphorylation of Ampk α and the activities of the glycolytic enzymes during the whole sampling period, while the opposite was true for the remaining indicators. Furthermore, metformin significantly upregulated the aforementioned indicators (except accα and fas) and the transcriptions of cpt IA and aco. Overall, metformin benefits the glucose homeostasis of Megalobrama amblycephala fed high-carbohydrate diets through the activation of Ampk and the stimulation of glycolysis, glycogenesis and fatty acid oxidation, while depressing gluconeogenesis and lipogenesis.

Open access

Trevor Lewis, Eva Zeisig, and Jamie E Gaida

Background

While metabolic health is acknowledged to affect connective tissue structure and function, the mechanisms are unclear. Glucocorticoids are present in almost every cell type throughout the body and control key physiological processes such as energy homeostasis, stress response, inflammatory and immune processes, and cardiovascular function. Glucocorticoid excess manifests as visceral adiposity, dyslipidemia, insulin resistance, and type 2 diabetes. As these metabolic states are also associated with tendinopathy and tendon rupture, it may be that glucocorticoids excess is the link between metabolic health and tendinopathy.

Objective

To synthesise current knowledge linking glucocorticoid exposure to tendon structure and function.

Methods

Narrative literature review.

Results

We provide an overview of endogenous glucocorticoid production, regulation, and signalling. Next we review the impact that oral glucocorticoid has on risk of tendon rupture and the effect that injected glucocorticoid has on resolution of symptoms. Then we highlight the clinical and mechanistic overlap between tendinopathy and glucocorticoid excess in the areas of visceral adiposity, dyslipidemia, insulin resistance and type 2 diabetes. In these areas, we highlight the role of glucocorticoids and how these hormones might underpin the connection between metabolic health and tendon dysfunction.

Conclusions

There are several plausible pathways through which glucocorticoids might mediate the connection between metabolic health and tendinopathy.

Open access

Angelo Maria Patti, Kalliopi Pafili, Nikolaos Papanas, and Manfredi Rizzo

Hormonal changes during pregnancy can trigger gestational diabetes (GDM), which is constantly increasing. Its main characteristic is pronounced insulin resistance, but it appears to be a multifactorial process involving several metabolic factors; taken together, the latter leads to silent or clinically evident cardiovascular (CV) events. Insulin resistance and central adiposity are of crucial importance in the development of metabolic syndrome, and they appear to correlate with CV risk factors, including hypertension and atherogenic dyslipidaemia. Hypertensive disease of pregnancy (HDP) is more likely to be an accompanying co-morbidity in pregnancies complicated with GDM. There is still inconsistent evidence as to whether or not co-existent GDM and HDP have a synergistic effects on postpartum risk of cardiometabolic disease; however, this synergism is becoming more accepted since both these conditions may promote endothelial inflammation and early atherosclerosis. Regardless of the presence or absence of the synergism between GDM and HDP, these conditions need to be dealt early enough, in order to reduce CV morbidity and to improve health outcomes for both women and their offspring.