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Introduction Gender dysphoria is characterized by a strong discomfort with the gender assigned at birth and the urge to live as a member of the opposite gender. The acquisition of phenotypic features of the desired gender requires the use of cross-sex hormones. Female-to-male (FtM) transsexual persons are treated with testosterone to induce virilization. Aim The aim of the study was to assess the effects of three different testosterone formulations on body weight and composition and metabolic and bone parameters. Methods Forty-five FtM transsexuals were randomly assigned to receive testoviron depot (i.m.: 100 mg/10 days; n = 15), testosterone gel (50 mg/die; n = 15), and testosterone undecanoate (i.m.: 1,000 mg every 6 weeks for the first 6 weeks and then every 12 weeks, n = 15). FtM individuals were studied before, at week 30, and at week 54 of testosterone treatment. Main Outcome Measures Anthropometric, metabolic, bone, hematological, and biochemical parameters were evaluated at baseline and after 12 months of treatment. Results Lean body mass significantly increased and fat mass decreased in all groups. No modifications were reported in fasting insulin and insulin sensitivity index. High-density plasma lipoprotein levels declined significantly and low-density lipoprotein concentrations increased significantly in the three groups. The activated partial thromboplastin time and factor I did not change while prothrombin time significantly increased in all groups. At week 54, all subjects were amenorrheic and time to amenorrhea did not differ between the three groups. Current general life satisfaction was increased in all subjects after 1 year of treatment. Conclusions One-year testosterone administration in FtM transsexuals appears to be very safe with no differences among the testosterone formulations used. Our study is preliminary, and the detection of subtle or long-term differences in the effects of the three formulations may require further larger and longer term studies in this and other populations.

Sarcopenia is a condition characterized by progressive and generalized reduction in skeletal muscle mass and muscle strength, associated with an increased risk of adverse outcomes (disability, hospitalization, death). The growing attention in the last years, aiming to establish a consensus definition and treatment, reflects the interest of the scientific community toward this complex condition, which has many implications in clinical practice and public health. Dual-energy X-ray absorptiometry (DXA) is the gold-standard technique in the analysis of body composition at molecular level, providing assessment and quantification of fat mass, lean mass and bone mineral content, both in a single body region of interest and at whole-body level. In particular, through the assessment of non-bone lean mass parameters, such as appendicular lean mass adjusted for BMI or height (ALM/BMI and ALM/ht, respectively), it is possible to discriminate subjects with "physiological" loss of muscle mass from those with "pathological" impoverishment of this compartment, referring to specific cutoff values validated in the literature, but keeping in mind the lack of standardization of DXA measures. In addition, it is useful in treatment planning, estimating resting energy expenditure, and in follow-up, because it allows quantifying with high reproducibility the modifications in BC, distinguishing when the change is biological (deterioration due to a progression of the disease or improvement due to treatment). Due to DXA favorability in terms of accuracy, simplicity, availability, low cost and low radiation exposure, its role in sarcopenia diagnosis is becoming increasingly important, emerging as reference assessment technique in muscle mass evaluation.

Aging is accompanied by physiological changes affecting body composition and functionality, including accumulation of fat mass at the expense of muscle mass, with effects upon morbidity and quality of life. The gut microbiome has recently emerged as a key environmental modifier of human health that can modulate healthy aging and possibly longevity. However, its associations with adiposity in old age are still poorly understood. Here we profiled the gut microbiota in a well-characterized cohort of 201 Italian elderly subjects from the NU-AGE study, by 16S rRNA amplicon sequencing. We then tested for association with body composition from dual-energy X-ray absorptiometry (DXA), with a focus on visceral and subcutaneous adipose tissue. Dietary patterns, serum metabolome and other health-related parameters were also assessed. This study identified distinct compositional structures of the elderly gut microbiota associated with DXA parameters, diet, metabolic profiles and cardio-metabolic risk factors.