Testosterone Restores Body Composition, Bone Mass, and Bone Strength Following Early Puberty Suppression in a Mouse Model Mimicking the Clinical Strategy in Trans Boys.

Transgender youth increasingly present at pediatric gender services. Some of them receive long-term puberty suppression with gonadotropin-releasing hormone analogues (GnRHa) before starting gender-affirming hormones (GAH). The impact of GnRHa use started in early puberty on bone composition and bone mass accrual is unexplored. It is furthermore unclear whether subsequent GAH fully restore GnRHa effects and whether the timing of GAH introduction matters. To answer these questions, we developed a mouse model mimicking the clinical strategy applied in trans boys. Prepubertal 4-week-old female mice were treated with GnRHa alone or with GnRHa supplemented with testosterone (T) from 6 weeks (early puberty) or 8 weeks (late puberty) onward. Outcomes were analyzed at 16 weeks and compared with untreated mice of both sexes. GnRHa markedly increased total body fat mass, decreased lean body mass, and had a modest negative impact on grip strength. Both early and late T administration shaped body composition to adult male levels, whereas grip strength was restored to female values. GnRHa-treated animals showed lower trabecular bone volume and reduced cortical bone mass and strength. These changes were reversed by T to female levels (cortical bone mass and strength) irrespective of the time of administration or even fully up to adult male control values (trabecular parameters) in case of earlier T start. The lower bone mass in GnRHa-treated mice was associated with increased bone marrow adiposity, also reversed by T. In conclusion, prolonged GnRHa use started in prepubertal female mice modifies body composition toward more fat and less lean mass and impairs bone mass acquisition and strength. Subsequent T administration counteracts GnRHa impact on these parameters, shaping body composition and trabecular parameters to male values while restoring cortical bone architecture and strength up to female but not male control levels. These findings could help guide clinical strategies in transgender care. © 2023 American Society for Bone and Mineral Research (ASBMR).

Combination of Bifidobacterium longum and Galacto-Oligosaccharide Protects the Skin from Photoaging.

Overexposure to ultraviolet B (UVB) irradiation induces photoaging that is characterized by the formation of wrinkles and loss of skin elasticity. To understand the mechanism of action of probiotics and prebiotics in skin protection against photoaging, we investigated the effects of dietary supplementation with the probiotic, Bifidobacterium longum, and prebiotic, galacto-oligosaccharide, on UVB-induced photoaging in hairless mice. We measured short chain fatty acid (SCFA) levels, antioxidant enzyme activity, and inflammatory signaling protein levels to elucidate the possible mechanisms underlying the effects of the dietary supplements B. longum and galacto-oligosaccharide. We observed that dietary supplementation with B. longum and galacto-oligosaccharide, individually and in combination, exerted protective effects against UVB-induced photoaging, showing anti-inflammatory and antioxidative effects. In particular, supplementation with the combination of B. longum and galacto-oligosaccharide showed stronger protective effects than supplementation with the probiotic or prebiotic alone. In addition, the serum levels of SCFAs and acetate were increased following dietary supplementation with B. longum and galacto-oligosaccharide, especially in combination. Therefore, we suggest that the combination of B. longum and galacto-oligosaccharide may potentially be used as a functional food to protect UVB-induced photoaging.

Testosterone Reduces Body Fat in Male Mice by Stimulation of Physical Activity Via Extrahypothalamic ERα Signaling.

Testosterone (T) reduces male fat mass, but the underlying mechanisms remain elusive, limiting its clinical relevance in hypogonadism-associated obesity. Here, we subjected chemically castrated high-fat diet-induced adult obese male mice to supplementation with T or the nonaromatizable androgen dihydrotestosterone (DHT) for 20 weeks. Both hormones increased lean mass, thereby indirectly increasing oxygen consumption and energy expenditure. In addition, T but not DHT decreased fat mass and increased ambulatory activity, indicating a role for aromatization into estrogens. Investigation of the pattern of aromatase expression in various murine tissues revealed the absence of Cyp19a1 expression in adipose tissue while high levels were observed in brain and gonads. In obese hypogonadal male mice with extrahypothalamic neuronal estrogen receptor alpha deletion (N-ERαKO), T still increased lean mass but was unable to decrease fat mass. The stimulatory effect of T on ambulatory activity was also abolished in N-ERαKO males. In conclusion, our work demonstrates that the fat-burning action of T is dependent on aromatization into estrogens and is at least partially mediated by the stimulation of physical activity via extrahypothalamic ERα signaling. In contrast, the increase in lean mass upon T supplementation is mediated through the androgen receptor and indirectly leads to an increase in energy expenditure, which might also contribute to the fat-burning effects of T.

Androgen action on renal calcium and phosphate handling: Effects of bisphosphonate treatment and low calcium diet.

Renal calcium and phosphate handling is an important contributor to mineral homeostasis and bone health and the androgen receptor (AR) is highly expressed in the kidney. We investigated the short term effects of androgen deprivation on renal calcium and phosphate reabsorption, independent of their effects on bone. Two weeks following orchidectomy (ORX) of adult mice, bone loss occurred along with hypercalciuria, which was similarly prevented by testosterone and dihydrotestosterone supplementation. Treatment with bisphosphonates prior to ORX also inhibited hypercalciuria, indicating that the calcium flux originated from the bone. Renal calcium and phosphate transporter expression was increased post-ORX, independent of bisphosphonates. Furthermore, androgen deprivation appeared to stimulate local synthesis of 1,25(OH)2D3. When bisphosphonate-treated mice were fed a low calcium diet, bone resorption was no longer blocked and secondary hyperparathyroidism developed, which was more pronounced in ORX mice than sham-operated mice. In conclusion, this study shows that androgen deprivation increased renal calcium and phosphate transporter expression, independent of bone, and underlines the importance of adequate intestinal calcium supply in circumstances of androgen deprivation and bisphosphonate treatment.

A Fomitopsis pinicola Jeseng Formulation Has an Antiobesity Effect and Protects against Hepatic Steatosis in Mice with High-Fat Diet-Induced Obesity.

This study investigated the antiobesity effect of an extract of the Fomitopsis pinicola Jeseng-containing formulation (FAVA), which is a combination of four natural components: Fomitopsis pinicola Jeseng; Acanthopanax senticosus; Viscum album coloratum; and Allium tuberosum. High-fat diet- (HFD-) fed male C57BL/6J mice were treated with FAVA (200 mg/kg/day) for 12 weeks to monitor the antiobesity effect and amelioration of nonalcoholic fatty liver diseases (NAFLD). Body and white adipose tissue (WAT) weights were reduced in FAVA-treated mice, and a histological examination showed an amelioration of fatty liver in FAVA-treated mice without decreasing food consumption. Additionally, FAVA reduced serum lipid profiles, leptin, and insulin levels compared with the HFD control group. The FAVA extract suppressed lipogenic mRNA expression levels from WAT concomitantly with the cholesterol biosynthesis level in the liver. These results demonstrate the inhibitory effects of FAVA on obesity and NAFLD in the diet-induced obese (DIO) mouse model. Therefore, FAVA may be an effective therapeutic candidate for treating obesity and fatty liver caused by a high-fat diet.

Over-expression of extracellular superoxide dismutase in mouse synovial tissue attenuates the inflammatory arthritis.

Oxidative stress such as reactive oxygen species (ROS) within the inflamed joint have been indicated as being involved as inflammatory mediators in the induction of arthritis. Correlations between extracellular- superoxide dismutase (EC-SOD) and inflammatory arthritis have been shown in several animal models of RA. However, there is a question whether the over-expression of EC-SOD on arthritic joint also could suppress the progression of disease or not. In the present study, the effect on the synovial tissue of experimental arthritis was investigated using EC-SOD over-expressing transgenic mice. The over-expression of EC- SOD in joint tissue was confirmed by RT-PCR and immunohistochemistry. The degree of the inflammation in EC-SOD transgenic mice was suppressed in the collagen-induced arthritis model. In a cytokine assay, the production of pro-inflammatory cytokines such as, IL-1ß, TNFα, and matrix metalloproteinases (MMPs) was decreased in fibroblast-like synoviocyte (FLS) but not in peripheral blood. Histological examination also showed repressed cartilage destruction and bone in EC-SOD transgenic mice. In conclusion, these data suggest that the over-expression of EC-SOD in FLS contributes to the activation of FLS and protection from joint destruction by depressing the production of the pro-inflammatory cytokines and MMPs. These results provide EC-SOD transgenic mice with a useful animal model for inflammatory arthritis research.

Differential effects of ziprasidone and haloperidol on immobilization-stress-induced CRF mRNA expression in the hypothalamic paraventricular nucleus of rats.

OBJECTIVES: Corticotropin-releasing factor (CRF) plays a prominent role in mediating the effect of stressors on the hypothalamic-pituitary-adrenal axis. In this study, we examined the effects of chronic administration of second-generation antipsychotic drug ziprasidone on CRF mRNA expression in the hypothalamic paraventricular nucleus (PVN) of rats with or without immobilization stress. METHODS: The rats were subjected to immobilization stress 2 h/day for 3 weeks. The effect of ziprasidone (2.5 mg/kg, 21 days) on CRF mRNA expression was determined using in situ hybridization of tissue sections from the rat hypothalamic PVN. Haloperidol (1.0 mg/kg, 21 days) was used for comparison. RESULTS: Haloperidol increased the expression of CRF mRNA in the PVN under basal conditions, whereas ziprasidone had no effect. Chronic immobilization stress increased CRF expression. The chronic administration of ziprasidone prevented the increase in CRF mRNA expression caused by immobilization stress. CONCLUSIONS: These results suggest that ziprasidone may have a regulatory effect on the stress-induced CRF mRNA expression and a role in the treatment of depressive mood symptom.