The Effect of Cross-Sex Fecal Microbiota Transplantation on Metabolism and Hormonal Status in Adult Rats

Increasing evidence of sexual dimorphism in the pathophysiology of metabolic complications caused by sex steroids is under investigation. The gut microbiota represents a complex microbial ecosystem involved in energy metabolism, immune response, nutrition acquisition, and the health of host organisms. Gender-specific differences in composition are present between females and males. The purpose of this study was to use cross-sex fecal microbiota transplantation (FMT) for the detection of sex-dependent metabolic, hormonal, and gut microbiota changes in female and male recipients. Healthy non-obese female and male Wistar rats were divided into donor, same-sex, and cross-sex recipient groups. After a 30-day period of FMT administration, biochemical markers (glucose and lipid metabolism) and sex hormones were measured, and the gut microbiota was analyzed. The cross-sex male recipients displayed a significantly lower testosterone concentration compared to the males that received same-sex FMT. Sex-dependent changes caused by cross-sex FMT were detected, while several bacterial taxa correlated with plasma testosterone levels. This study represents the first to study the effect of cross-sex changes in the gut microbiome concerning metabolic and hormonal changes/status in adult non-obese Wistar rats. Herein, we present cross-sex FMT as a potential tool to modify sex-specific pathologies.

Early puberty suppression and gender-affirming hormones do not alter final height in transgender adolescents

BACKGROUND

Early puberty suppression (ePS; Tanner stages 2 and 3) through gonadotropin-releasing hormone agonists (GnRHas) and gender-affirming hormones (GAHs) interferes with growth and may impact final height (FH).

AIM

To investigate the impact of ePS and GAH on FH in trans boys and trans girls.

METHODS

Retrospective study, including 10 trans boys and 22 trans girls at FH. Bone age (BA) was determined at the start of ePS and at the start of GAH according to Greulich and Pyle; predicted adult height (PAH) was calculated according to Bayley and Pinneau's tables; target height (TH) was calculated as adjusted mean of maternal and paternal height. Target height, PAH, and BA were determined according to sex registered at birth (SRAB) and experienced gender (EG).

RESULTS

The age at the start of PS was 12.37 ± 0.74 years in trans boys and 13.10 ± 1.12 years in trans girls. Total height gain since the start of ePS in trans boys was 14.62 ± 4.08 cm, with 70% achieved before the start of GAH. In trans girls, it was 20.68 ± 7.66 cm, with 61% achieved before GAH. Target height for SRAB was the most accurate predictor for FH in both trans boys and girls: the difference with FH was 1.57 cm ± 3.1 (P = .168) and -0.98 cm ± 4.17 (P = .319), respectively. Also the difference between FH and PAH at the start of PS for SRAB was nonsignificant in both trans boys and girls (2.62 cm ± 3.79, P = .056 and -2.35 cm ± 5.2, P = .051, respectively).

CONCLUSION

Early puberty suppression and GAH do not impact FH, supporting the safety of the treatment; however, trans adolescents achieve a FH in line with SRAB, rather than EG.