The GOAT-Ghrelin System Is Not Essential for Hypoglycemia Prevention during Prolonged Calorie Restriction

Ghrelin acylation by ghrelin O-acyltransferase (GOAT) has recently been reported to be essential for the prevention of hypoglycemia during prolonged negative energy balance. Using a unique set of four different genetic loss-of-function models for the GOAT/ghrelin/growth hormone secretagogue receptor (GHSR) system, we thoroughly tested the hypothesis that lack-of-ghrelin activation or signaling would lead to hypoglycemia during caloric deprivation. Male and female knockout (KO) mice for GOAT, ghrelin, GHSR, or both ghrelin and GHSR (dKO) were subjected to prolonged calorie restriction (40% of ad libitum chow intake). Body weight, fat mass, and glucose levels were recorded daily and compared to wildtype (WT) controls. Forty-eight hour blood glucose profiles were generated for each individual mouse when 2% or less body fat mass was reached. Blood samples were obtained for analysis of circulating levels of acyl- and desacyl-ghrelin, IGF-1, and insulin. Chronic calorie restriction progressively decreased body weight and body fat mass in all mice regardless of genotype. When fat mass was depleted to 2% or less of body weight for 2 consecutive days, random hypoglycemic events occurred in some mice across all genotypes. There was no increase in the incidence of hypoglycemia in any of the four loss-of-function models for ghrelin signaling including GOAT KO mice. Furthermore, no differences in insulin or IGF-1 levels were observed between genotypes. The endogenous GOAT-ghrelin-GHSR system is not essential for the maintenance of euglycemia during prolonged calorie restriction

Developing Standard Treatment Workflows—way to universal healthcare in India

Primary healthcare caters to nearly 70% of the population in India and provides treatment for approximately 80–90% of common conditions. To achieve universal health coverage (UHC), the Indian healthcare system is gearing up by initiating several schemes such as National Health Protection Scheme, Ayushman Bharat, Nutrition Supplementation Schemes, and Inderdhanush Schemes. The healthcare delivery system is facing challenges such as irrational use of medicines, over- and under-diagnosis, high out-of-pocket expenditure, lack of targeted attention to preventive and promotive health services, and poor referral mechanisms. Healthcare providers are unable to keep pace with the volume of growing new scientific evidence and rising healthcare costs as the literature is not published at the same pace. In addition, there is a lack of common standard treatment guidelines, workflows, and reference manuals from the Government of India. Indian Council of Medical Research in collaboration with the National Health Authority, Govt. of India, and the WHO India country office has developed Standard Treatment Workflows (STWs) with the objective to be utilized at various levels of healthcare starting from primary to tertiary level care. A systematic approach was adopted to formulate the STWs. An advisory committee was constituted for planning and oversight of the process. Specialty experts' group for each specialty comprised of clinicians working at government and private medical colleges and hospitals. The expert groups prioritized the topics through extensive literature searches and meeting with different stakeholders. Then, the contents of each STW were finalized in the form of single-pager infographics. These STWs were further reviewed by an editorial committee before publication. Presently, 125 STWs pertaining to 23 specialties have been developed. It needs to be ensured that STWs are implemented effectively at all levels and ensure quality healthcare at an affordable cost as part of UHC

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

GOAT ablation does not improve glucose homeostasis in mice on a leptin-deficient ob/ob background.

<p>a) Fasting insulin levels in 4-month-old chow-fed WT, GOAT-KO, ob/ob mutant and GOAT-ob/ob mice. b) Glucose tolerance tests (b left panel; 1 g glucose/kg body weight) in chow-fed mice revealed no improvement in glucose tolerance by GOAT ablation. Insulin tolerance tests in mice fed with MCT diet (b right panel; 0.75 U insulin/kg body weight) suggested severe insulin resistance in both GOAT-ob/ob and ob/ob mutant mice, and a normal insulin sensitivity in GOAT-KO and dWT mice. (n = 6–10).</p

Body weight, fat mass and fat free mass in male mice lacking GOAT on a leptin-deficient ob/ob background.

<p>GOAT-ob/ob mice fed standard chow diet display no differences in body weight (a), fat mass (b), or fat free mass (c), compared to ob/ob littermates. However, both leptin-deficient mutants differ significantly in their body adiposity from GOAT-KO and dWT mice, respectively. ** P<0.01 (1-way ANOVA); (n = 5–7).</p

Total ghrelin levels in WT and GOAT-KO mice on a normal or leptin-deficient ob/ob background.

<p>GOAT-KO and GOAT-ob/ob mice with a complete lack of acyl ghrelin have increased plasma concentration of total (desacyl) ghrelin. Total ghrelin levels are lower in both ob/ob as well as GOAT-ob/ob mice, compared to lean WT controls or GOAT-KO mice on chow diet. ^# P<0.05 versus dWT; ** P<0.001 versus GOAT-KO; ^$$ P<0.001 versus ob/ob; n = 4–7.</p

Genotyping conditions.

<p>Fwd, forward; Rev, reverse; bp, base pairs; Mboat4, Membrane bound-O-acyl transferase 4; ob, obese.</p

Metabolic phenotypes of ob/ob mutants and GOAT-ob/ob double mutants after exposure to medium-chain triglyceride (MCT) enriched diet.

<p>Leptin-deficient ob/ob and GOAT-ob/ob double mutant mice were fed MCT diet for 8 weeks. No differences were observed for body weight (a) and fat mass or fat free mass (b). Further, indirect calorimetry after 7 weeks of MCT diet exposure revealed no differences in food intake (c), energy expenditure (d), respiratory quotients (e) or locomotor activity (f, P = 0.16). (n = 4–7).</p

Calcineurin A beta deficiency ameliorates HFD-induced hypothalamic astrocytosis in mice

Abstract ᅟ Astrocytosis is a reactive process involving cellular, molecular, and functional changes to facilitate neuronal survival, myelin preservation, blood brain barrier function and protective glial scar formation upon brain insult. The overall pro- or anti-inflammatory impact of reactive astrocytes appears to be driven in a context- and disease-driven manner by modulation of astrocytic Ca2+ homeostasis and activation of Ca2+/calmodulin-activated serine/threonine phosphatase calcineurin. Here, we aimed to assess whether calcineurin is dispensable for astrocytosis in the hypothalamus driven by prolonged high fat diet (HFD) feeding. Global deletion of calcineurin A beta (gene name: Ppp3cb) led to a decrease of glial fibrillary acidic protein (GFAP)-positive cells in the ventromedial hypothalamus (VMH), dorsomedial hypothalamus (DMH), and arcuate nucleus (ARC) of mice exposed chronically to HFD. The concomitant decrease in Iba1-positive microglia in the VMH further suggests a modest impact of Ppp3cb deletion on microgliosis. Pharmacological inhibition of calcineurin activity by Fk506 had no impact on IBA1-positive microglia in hypothalami of mice acutely exposed to HFD for 1 week. However, Fk506-treated mice displayed a decrease in GFAP levels in the ARC. In vivo effects could not be replicated in cell culture, where calcineurin inhibition by Fk506 had no effect on astrocytic morphology, astrocytic cell death, GFAP, and vimentin protein levels or microglia numbers in primary hypothalamic astrocytes and microglia co-cultures. Further, adenoviral overexpression of calcineurin subunit Ppp3r1 in primary glia culture did not lead to an increase in GFAP fluorescence intensity. Overall, our results point to a prominent role of calcineurin in mediating hypothalamic astrocytosis as response to acute and chronic HFD exposure. Moreover, discrepant findings in vivo and in cell culture indicate the necessity of studying astrocytes in their “natural” environment, i.e., preserving an intact hypothalamic microenvironment with neurons and non-neuronal cells in close proximity

FGF21 regulates insulin sensitivity following long-term chronic stress

Objective: Post-traumatic stress disorder (PTSD) increases type 2 diabetes risk, yet the underlying mechanisms are unclear. We investigated how early-life exposure to chronic stress affects long-term insulin sensitivity. Methods: C57Bl/6J mice were exposed to chronic variable stress for 15 days (Cvs) and then recovered for three months without stress (Cvs3m). Results: Cvs mice showed markedly increased plasma corticosterone and hepatic insulin resistance. Cvs3m mice exhibited improved whole-body insulin sensitivity along with enhanced adipose glucose uptake and skeletal muscle mitochondrial function and fatty acid oxidation. Plasma FGF21 levels were substantially increased and associated with expression of genes involved in fatty acid oxidation and formation of brown-like adipocytes. In humans, serum FGF21 levels were associated with stress coping long time after the exposure. Conclusions: Early-life exposure to chronic stress leads to long term improvements in insulin sensitivity, oxidative metabolism and adipose tissue remodeling. FGF21 contributes to a physiological memory mechanism to maintain metabolic homeostasis. Keywords: PTSD, Chronic variable stress, Diabetes, Insulin sensitivity, FGF21, White adipose tissu