Volume 15 Issue 3, March 2019

The recently released physical activity guidelines for Americans advise that adults should do at least 150–300 minutes of moderate intensity aerobic physical activity per week. The scientific evidence clearly shows benefits of physical activity for a wide variety of health outcomes. However, are these guidelines also sufficient to prevent unhealthy weight gain?

A recent study has shown that obesity and ageing induce T cell dysfunction and an upregulation of programmed cell death 1 (PD-1) on T cells across species, which is partially mediated by leptin. However, the polarization of T cells towards an exhaustive phenotype correlated with improved response rates to anti-PD-1 therapy in the setting of obesity.

Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy are currently the most popular bariatric procedures worldwide; however, there is ongoing debate regarding which is more effective. A new study involving a large multicentre cohort demonstrates significantly more weight loss with RYGB than with sleeve gastrectomy, but with almost double the rate of complications.

As the global increase in type 2 diabetes mellitus has a steep upward slope, meeting the worldwide demand for insulin is an international challenge. Sanjay Basu and colleagues used microsimulation to create scenarios that can inform the design of health-care strategies and insulin requirements for governments and the national and international organizations responsible for formulating treatment guidelines.

The association between obesity and increased risk of developing cancer is partly driven by disruption of metabolism and inflammation in the adipose tissue. This Review discusses changes in the adipose tissue microenvironment during body-weight gain and how these changes affect tumour initiation and growth.

Loss or dysfunction of β-cells is a characteristic of insulin-dependent diabetes mellitus. Regeneration of β-cells might stop or reverse the progression of the disease. This Review discusses the different modelling systems and technologies currently used to study β-cell biology in health and disease.

Post-transplant diabetes mellitus (PTDM) is a common complication of solid organ transplantation that can result in increased mortality. This Review outlines the pathogenesis, diagnosis, treatment and prevention of PTDM.