Obesity-induced insulin resistance is the major determinant of metabolic syndrome, which precedes the development of type 2 diabetes mellitus and is thus the driving force behind the emerging diabetes epidemic. The precise causes of insulin resistance are varied, and the relative importance of each is a matter of ongoing research. Here, we offer a Perspective on the heterogeneous etiology of insulin resistance, focusing in particular on the role of inflammation, lipid metabolism, and the gastrointestinal microbiota.

This study evaluated prototype multichannel nonlinear frequency compression (NFC) signal processing on listeners with high-frequency hearing loss. This signal processor applies NFC above a cut-off frequency. The participants were hearing-impaired adults (13) and children (11) with sloping, high-frequency hearing loss. Multiple outcome measures were repeated using a modified withdrawal design. These included speech sound detection, speech recognition, and self-reported preference measures. Group level results provide evidence of significant improvement of consonant and plural recognition when NFC was enabled. Vowel recognition did not change significantly. Analysis of individual results allowed for exploration of individual factors contributing to benefit received from NFC processing. Findings suggest that NFC processing can improve high frequency speech detection and speech recognition ability for adult and child listeners. Variability in individual outcomes related to factors such as degree and configuration of hearing loss, age of participant, and type of outcome measure.

Chronic inflammation is a key component of obesity–induced insulin resistance and plays a central role in metabolic disease. In this study, we found that the major insulin target tissues, liver, muscle and adipose tissue exhibit increased levels of the chemotactic eicosanoid LTB4 in obese high fat diet (HFD) mice compared to lean chow fed mice. Inhibition of the LTB4 receptor, Ltb4r1, through either genetic or pharmacologic loss of function results in an anti–inflammatory phenotype with protection from systemic insulin resistance and hepatic steatosis in the setting of both HFD–induced and genetic obesity. Importantly, in vitro treatment with LTB4 directly enhanced macrophage chemotaxis, stimulated inflammatory pathways in macrophages, promoted de novo hepatic lipogenesis, decreased insulin stimulated glucose uptake in L6 myocytes, increased gluconeogenesis, and impaired insulin–mediated suppression of hepatic glucose output (HGO) in primary mouse hepatocytes. This was accompanied by decreased insulin stimulated Akt phosphorylation and increased Irs1 and Irs2 serine phosphorylation and all of these events were Gαi and Jnk dependent. Taken together, these observations elucidate a novel role of LTB4/Ltb4r1 in the etiology of insulin resistance in hepatocytes and myocytes, and shows that in vivo inhibition of Ltb4r1 leads to robust insulin sensitizing effects.

SUMMARY In obesity, macrophages and other immune cells accumulate in insulin target tissues, promoting a chronic inflammatory state and insulin resistance. Galectin-3 (Gal3), a lectin mainly secreted by macrophages, is elevated in both obese subjects and mice. Administration of Gal3 to mice causes insulin resistance and glucose intolerance, whereas inhibition of Gal3, through either genetic or pharmacologic loss of function, improved insulin sensitivity in obese mice. In vitro treatment with Gal3 directly enhanced macrophage chemotaxis, reduced insulin stimulated glucose uptake in myocytes and 3T3-L1 adipocytes and impaired insulin-mediated suppression of glucose output in primary mouse hepatocytes. Importantly, we found that Gal3 can bind directly to the insulin receptor (IR) and inhibit downstream IR signaling. These observations elucidate a novel role for Gal3 in hepatocytes, adipocytes and myocyte insulin resistance, suggesting that Gal3 can link inflammation to decreased insulin sensitivity. Inhibition of Gal3 could be a new approach to treat insulin resistance.

The intestinal microbiome can regulate host energy homeostasis and the development of metabolic disease. Here we identify GPR43, a receptor for bacterially produced short-chain fatty acids (SCFAs), as a modulator of microbiota-host interaction. β-Cell expression of GPR43 and serum levels of acetate, an endogenous SCFA, are increased with a high-fat diet (HFD). HFD-fed GPR43 knockout (KO) mice develop glucose intolerance due to a defect in insulin secretion. In vitro treatment of isolated murine islets, human islets, and Min6 cells with (S)-2-(4-chlorophenyl)-3,3-dimethyl-N-(5-phenylthiazol-2-yl)butanamide (PA), a specific agonist of GPR43, increased intracellular inositol triphosphate and Ca2+ levels, and potentiated insulin secretion in a GPR43-, Gαq-, and phospholipase C–dependent manner. In addition, KO mice fed an HFD displayed reduced β-cell mass and expression of differentiation genes, and the treatment of Min6 cells with PA increased β-cell proliferation and gene expression. Together these findings identify GPR43 as a potential target for therapeutic intervention.

This meta-analysis examined 36 studies comparing autism spectrum disorder (ASD) and control groups in reading comprehension. Three moderators (semantic knowledge, decoding skill, PIQ) and two text types (high vs. low social knowledge) were examined as predictors of reading comprehension in ASD. The overall standardized mean difference for reading comprehension was g = -0.7 SD. The strongest individual predictors of reading comprehension were semantic knowledge (explaining 57 % of variance) and decoding skill (explaining 55 % of variance). Individuals with ASD were significantly worse at comprehending highly social than less social texts. Having ASD alone does not predict reading comprehension deficits. Instead, individual skills, especially language ability, must be considered before one can accurately predict whether a given individual with ASD will experience difficulties in reading comprehension.

The childcare environment represents an appropriate avenue to support physical activity among preschoolers. The aim of this study was two-fold: (1) to measure the physical activity levels of a sample of preschoolers during childcare hours; and (2) to assess which attributes (e.g., space, equipment, policies) within centre-based childcare environments influenced physical activity. Thirty-one preschoolers from 5 childcare centres across London, Canada participated. Actical accelerometers were worn by participants for one day during childcare hours to assess activity levels using a 15 second epoch length. The Environment and Policy Assessment and Observation instrument was used to conduct a full-day evaluation of the childcare environment. On average, participants engaged in 1.54 min/h of moderate-to-vigorous physical activity and 17.42 min/h of total physical activity. Sedentary opportunities, portable and fixed play equipment, and staff behaviour accounted for 49.3% of the variability in moderate-to-vigorous physical activity and 14.1% of the variability in total physical activity, with sedentary opportunities, fixed play equipment, and staff behaviours displaying an inverse relationship. Results emphasize the critical role the childcare environment plays in supporting physical activity among preschoolers.

SUMMARY The role of inflammation in obesity-related pathologies is well established. We investigated the therapeutic potential of LipoxinA4 (LXA4:5(S),6(R),15(S)-trihydroxy-7E,9E,11Z,13E,-eicosatetraenoic acid) and a synthetic 15(R)-Benzo-LXA4-analogue, as interventions in a 3-month high-fat-diet [HFD; 60%fat]-induced obesity model. Obesity caused distinct pathologies, including impaired glucose-tolerance, adipose inflammation, fatty liver and chronic-kidney-disease (CKD). Lipoxins (LXs) attenuated obesity- induced CKD; reducing glomerular expansion, mesangial matrix and urinary H2O2. Furthermore, LXA4 reduced liver weight, serum alanine-aminotransferase and hepatic triglycerides. LXA4 decreased obesity-induced adipose inflammation, attenuating TNF-α and CD11c+ M1-macrophages (MΦs), while restoring CD206+ M2-MΦs and increasing Annexin-1. LXs did not affect renal or hepatic MΦs, suggesting protection occurred via attenuation of adipose inflammation. LXs restored adipose expression of autophagy markers LC3-II and p62. LX-mediated protection was demonstrable in adiponectin−/− mice, suggesting that the mechanism was adiponectin independent. In conclusion, LXs protect against obesity- induced systemic disease and these data support a novel therapeutic paradigm for treating obesity and associated pathologies.