MC3R links nutritional state to childhood growth and the timing of puberty.

The state of somatic energy stores in metazoans is communicated to the brain, which regulates key aspects of behaviour, growth, nutrient partitioning and development1. The central melanocortin system acts through melanocortin 4 receptor (MC4R) to control appetite, food intake and energy expenditure2. Here we present evidence that MC3R regulates the timing of sexual maturation, the rate of linear growth and the accrual of lean mass, which are all energy-sensitive processes. We found that humans who carry loss-of-function mutations in MC3R, including a rare homozygote individual, have a later onset of puberty. Consistent with previous findings in mice, they also had reduced linear growth, lean mass and circulating levels of IGF1. Mice lacking Mc3r had delayed sexual maturation and an insensitivity of reproductive cycle length to nutritional perturbation. The expression of Mc3r is enriched in hypothalamic neurons that control reproduction and growth, and expression increases during postnatal development in a manner that is consistent with a role in the regulation of sexual maturation. These findings suggest a bifurcating model of nutrient sensing by the central melanocortin pathway with signalling through MC4R controlling the acquisition and retention of calories, whereas signalling through MC3R primarily regulates the disposition of calories into growth, lean mass and the timing of sexual maturation.

An evaluation of a pilot of daily testing of SARS-CoV-2 contacts in acute hospital and ambulance trusts in England.

OBJECTIVES: Healthcare worker (HCW) SARS-CoV-2 contacts in England have been required to quarantine, creating staff shortages. We piloted daily contact testing (DCT) to assess its feasibility as an alternative. STUDY DESIGN: Observational service evaluation. METHODS: We conducted an observational service evaluation of 7-day DCT using antigen lateral flow devices (LFDs) at four acute hospital trusts and one ambulance trust in England. Mixed methods were used, using aggregate and individual-level test monitoring data, semi-structured interviews, and a survey of eligible contacts. RESULTS: In total, 138 HCWs were identified as contacts of a confirmed SARS-CoV-2 case. Of these, 111 (80%) consented to daily LFD testing, of whom 82 (74%) completed the required programme without interruption and 12 (11%) completed with interruption. Fifty-eight participants (52%) and two non-participants (7.4%) completed the survey. In total, 28 interviews were conducted with participants, site and infection control leads, and union representatives. One participant tested positive on LFD and polymerase chain reaction (PCR) test. Three participants tested positive on PCR but not LFD. DCT was well-accepted by trusts and staff. Participants reported no relaxation of their infection prevention and control behaviours. No incidents of transmission were detected. An estimated 729 potential days of work absence were averted. CONCLUSIONS: DCT can be acceptably operated in a healthcare setting, averting quarantine-related work absences in HCW SARS-CoV-2 contacts.

Type 2 diabetes is associated with the accumulation of senescent T cells.

Type 2 diabetes is a global health priority, given that it is driven, in part, by an ageing population, the role of immune senescence has been overlooked. This is surprising, as the functional impairments of senescent T cells show strong similarities to patients with hyperglycaemia. Immune senescence is typified by alterations in T cell memory, such as the accumulation of highly differentiated end-stage memory T cells, as well as a constitutive low-grade inflammation, which drives further immune differentiation. We show here in a preliminary study that people living with type 2 diabetes have a higher circulating volume of senescent T cells accompanied with a higher level of systemic inflammation. This inflammatory environment drives the expression of a unique array of chemokine receptors on senescent T cells, most notably C-X-C motif chemokine receptor type 2. However, this increased expression of migratory markers does not translate to improved extravasation owing to a lack of glucose uptake by the T cells. Our results therefore demonstrate that the presence of senescent T cells has a detrimental impact on immune function during type 2 diabetes.

Setting the top 10 research priorities to improve the health of people with Type 2 diabetes: a Diabetes UK-James Lind Alliance Priority Setting Partnership.

AIMS: To describe processes and outcomes of a priority setting partnership to identify the 'top 10 research priorities' in Type 2 diabetes, involving people living with the condition, their carers, and healthcare professionals. METHODS: We followed the four-step James Lind Alliance Priority Setting Partnership process which involved: gathering uncertainties using a questionnaire survey distributed to 70 000 people living with Type 2 diabetes and their carers, and healthcare professionals; organizing the uncertainties; interim priority setting by resampling of participants with a second survey; and final priority setting in an independent group of participants, using the nominal group technique. At each step the steering group closely monitored and guided the process. RESULTS: In the first survey, 8227 uncertainties were proposed by 2587 participants, of whom 18% were from black, Asian and minority ethnic groups. Uncertainties were formatted and collated into 114 indicative questions. A total of 1506 people contributed to a second survey, generating a shortlist of 24 questions equally weighted to the contributions of people living with diabetes and their carers and those of healthcare professionals. In the final step the 'top 10 research priorities' were selected, including questions on cure and reversal, risk identification and prevention, and self-management approaches in Type 2 diabetes. CONCLUSION: Systematic and transparent methodology was used to identify research priorities in a large and genuine partnership of people with lived and professional experience of Type 2 diabetes. The top 10 questions represent consensus areas of research priority to guide future research, deliver responsive and strategic allocation of research resources, and improve the future health and well-being of people living with, and at risk of, Type 2 diabetes.

The role of the one-carbon cycle in the developmental origins of Type 2 diabetes and obesity.

Vitamin B12 deficiency is common in certain populations, such as in India, where there is also a rising prevalence of Type 2 diabetes, obesity and their complications. Human cohorts and animal models provide compelling data suggesting the role of the one-carbon cycle in modulating the risk of diabetes and adiposity via developmental programming. Early mechanistic studies in animals suggest that alterations to the cellular provision of methyl groups (via the one-carbon cycle) in early developmental life may disrupt DNA methylation and induce future adverse phenotypic changes. Furthermore, replacement of micronutrient deficits at suitable developmental stages may modulate this risk. Current human studies are limited by a range of factors, including the accuracy and availability of methods to measure nutritional components in the one-carbon cycle, and whether its disruptions exert tissue-specific effects. A greater understanding of the causal and mechanistic role of the one-carbon cycle is hoped to generate substantial insights into its role in the developmental origins of complex metabolic diseases and the potential of targeted and population-wide prevention strategies.

Is famine exposure during developmental life in rural Bangladesh associated with a metabolic and epigenetic signature in young adulthood? A historical cohort study.

OBJECTIVES: Famine exposure in utero can 'programme' an individual towards type 2 diabetes and obesity in later life. We sought to identify, (1) whether Bangladeshis exposed to famine during developmental life are programmed towards diabetes and obesity, (2) whether this programming was specific to gestational or postnatal exposure windows and (3) whether epigenetic differences were associated with famine exposure. DESIGN: A historical cohort study was performed as part of a wider cross-sectional survey. Exposure to famine was defined through birth date and historical records and participants were selected according to: (A) exposure to famine in postnatal life, (B) exposure to famine during gestation and (C) unexposed. SETTING: Matlab, a rural area in the Chittagong division of Bangladesh. PARTICIPANTS: Young adult men and women (n=190) recruited to a historical cohort study with a randomised subsample included in an epigenetic study (n=143). OUTCOME MEASURES: Primary outcome measures of weight, body mass index and oral glucose tolerance tests (0 and 120 min glucose). Secondary outcome measures included DNA methylation using genome-wide and targeted analysis of metastable epialleles sensitive to maternal nutrition. RESULTS: More young adults exposed to famine in gestation were underweight than those postnatally exposed or unexposed. In contrast, more young adults exposed to famine postnatally were overweight compared to those gestationally exposed or unexposed. Underweight adults exposed to famine in gestation in utero were hyperglycaemic following a glucose tolerance test, and those exposed postnatally had elevated fasting glucose, compared to those unexposed. Significant differences in DNA methylation at seven metastable epialleles (VTRNA2-1, PAX8, PRDM-9, near ZFP57, near BOLA, EXD3) known to vary with gestational famine exposure were identified. CONCLUSIONS: Famine exposure in developmental life programmed Bangladeshi offspring towards diabetes and obesity in adulthood but gestational and postnatal windows of exposure had variable effects on phenotype. DNA methylation differences were replicated at previously identified metastable epialleles sensitive to periconceptual famine exposure.

Drug therapy after very-low-calorie diets.

Very-low-calorie diets (VLCDs) are effective at reducing weight, even in patients who have often failed with conventional diets. Maintaining weight lost by means of a VLCD remains a clinical challenge. Attempts to prevent weight regain by dietary reeducation or by more formal behavior-modification techniques are not easily applicable to large numbers of patients and are not always successful; the use of drugs to maintain and improve upon initial VLCD success could be of real clinical value. Pharmacological treatment of obesity has evolved in recent years with the development and licensing of potent serotonin agonists, such as dexfenfluramine (dF), acting as nonstimulant anorectic agents. Thermogenic drugs are not yet as advanced in clinical development and evaluation but offer the prospect of increasing energy output in the reduced obese patient. Drugs used to treat obesity need to be effective, to be safe, not to exhibit drug tolerance, and ideally, to be shown to reduce morbidity or mortality from obesity, particularly because treatment will need to be prolonged. Such requirements are not unique for treating obesity, they are similar for drugs used to treat other metabolic diseases such as hypercholesterolemia or diabetes. VLCD followed by dF has been shown to be effective. A double-blind trial randomized 45 patients who had successfully completed 8 wk of treatment on the Cambridge diet to either placebo or dF 15 mg twice daily for 26 wk. Patients continued on a diet giving 60-75% of daily energy needs.(ABSTRACT TRUNCATED AT 250 WORDS)