Sex differences in metabolic regulation and diabetes susceptibility.

Gender and biological sex impact the pathogenesis of numerous diseases, including metabolic disorders such as diabetes. In most parts of the world, diabetes is more prevalent in men than in women, especially in middle-aged populations. In line with this, considering almost all animal models, males are more likely to develop obesity, insulin resistance and hyperglycaemia than females in response to nutritional challenges. As summarised in this review, it is now obvious that many aspects of energy balance and glucose metabolism are regulated differently in males and females and influence their predisposition to type 2 diabetes. During their reproductive life, women exhibit specificities in energy partitioning as compared with men, with carbohydrate and lipid utilisation as fuel sources that favour energy storage in subcutaneous adipose tissues and preserve them from visceral and ectopic fat accumulation. Insulin sensitivity is higher in women, who are also characterised by higher capacities for insulin secretion and incretin responses than men; although, these sex advantages all disappear when glucose tolerance deteriorates towards diabetes. Clinical and experimental observations evidence the protective actions of endogenous oestrogens, mainly through oestrogen receptor α activation in various tissues, including the brain, the liver, skeletal muscle, adipose tissue and pancreatic beta cells. However, beside sex steroids, underlying mechanisms need to be further investigated, especially the role of sex chromosomes, fetal/neonatal programming and epigenetic modifications. On the path to precision medicine, further deciphering sex-specific traits in energy balance and glucose homeostasis is indeed a priority topic to optimise individual approaches in type 2 diabetes prevention and treatment.

Is MRI follow-up relevant in patients with GH-secreting pituitary adenomas primarily treated and responsive to long-acting somatostatin analogues (SMSa)?

OBJECTIVE: Primary SMSa treatment can be associated with hormonal control and tumor shrinkage in patients with GH-secreting pituitary adenomas. The aim of this study was to evaluate whether regular MRI follow-up was necessary in patients with acromegaly-treated and responsive to first-generation long-acting SMSa. PATIENTS AND METHODS: In this retrospective monocentric study we included patients with GH/IGF-1 hypersecretion and pituitary adenomas with normal visual field, primarily treated with first-generation long-acting SMSa between 1995 and 2015 and regularly monitored (clinical evaluation, GH/IGF-1 levels and pituitary MRI) for at least 3 years. RESULTS: We included 83 patients (32 men and 51 women, mean age at diagnosis 50 ± 12 years) with mean GH = 19.3 ± 25.6 ng/mL, IGF-1 = 284 ± 110% ULN and pituitary adenoma height = 12.9 ± 4.7 mm. Mean follow-up was 8.9 ± 4.9 years in 36 controlled patients and 2.0 ± 1.6 years in 47 partial responders to SMSa alone. No significant increase in pituitary adenoma height was observed. Pituitary adenoma height decreased significantly in controlled patients (diagnosis: 11.9 ± 4.8 mm, SMSa: 9.6 ± 3.3 mm, P < 0.001), and in partially responders (diagnosis: 13.6 ± 4.5 mm, SMSa: 11.5 ± 4.5 mm, P < 0.001). CONCLUSION: During SMSa treatment, no significant increase in GH-secreting adenoma size was observed. Primary SMSa treatment was associated with a significantly decrease in adenoma height in our population. Our cohort data suggest that regular MRI follow-up does not seem relevant in patients with acromegaly who are responsive to SMSa treatment.