The effect of gonadotropin-releasing hormone agonist on type I collagen C-telopeptide and N-telopeptide: the predictive value of biochemical markers of bone turnover

Effect of pubertal suppression and cross-sex hormone therapy on bone turnover markers and bone mineral apparent density (BMAD) in transgender adolescents

Puberty is highly important for the accumulation of bone mass. Bone turnover and bone mineral density (BMD) can be affected in transgender adolescents when puberty is suppressed by gonadotropin-releasing hormone analogues (GnRHa), followed by treatment with cross-sex hormone therapy (CSHT). We aimed to investigate the effect of GnRHa and CSHT on bone turnover markers (BTMs) and bone mineral apparent density (BMAD) in transgender adolescents. Gender dysphoria was diagnosed based on diagnostic criteria according to the DSM-IV (TR). Thirty four female-to-male persons (transmen) and 22 male-to-female persons (transwomen)were included. Patients were allocated to a young (bone age of <15years in transwomen or <14 in transmen) or old group (bone age of ≥15years in transwomen or ≥14years in transmen). All were treated with GnRHa triptorelin and CSHT was added in incremental doses from the age of 16years. Transmen received testosterone esters (Sustanon, MSD) and transwomen received 17-β estradiol. P1NP, osteocalcin, ICTP and BMD of lumbar spine (LS) and femoral neck (FN) were measured at three time points. In addition, BMAD and Z-scores were calculated. We found a decrease of P1NP and 1CTP during GnRHa treatment, indicating decreased bone turnover (young transmen 95% CI -74 to -50%, p=0.02, young transwomen 95% CI -73 to -43, p=0.008). The decrease in bone turnover upon GnRHa treatment was accompanied by an unchanged BMAD of FN and LS, whereas BMAD Z-scores of predominantly the LS decreased especially in the young transwomen. Twenty-four months after CSHT the BTMs P1NP and ICTP were even more decreased in all groups except for the old transmen. During CSHT BMAD increased and Z-scores returned towards normal, especially of the LS (young transwomen CI 95% 0.1 to 0.6, p=0.01, old transwomen 95% CI 0.3 to 0.8, p=0.04). To conclude, suppressing puberty by GnRHa leads to a decrease of BTMs in both transwomen and transmen transgender adolescents. The increase of BMAD and BMAD Z-scores predominantly in the LS as a result of treatment with CSHT is accompanied by decreasing BTM concentrations after 24months of CSHT. Therefore, the added value of evaluating BTMs seems to be limited and DXA-scans remain important in follow-up of bone health of transgender adolescents.

Integrated pharmacometrics and systems pharmacology model-based analyses to guide GnRH receptor modulator development for management of endometriosis

Endometriosis is a gynecological condition resulting from proliferation of endometrial-like tissue outside the endometrial cavity. Estrogen suppression therapies, mediated through gonadotropin-releasing hormone (GnRH) modulation, decrease endometriotic implants and diminish associated pain albeit at the expense of bone mineral density (BMD) loss. Our goal was to provide model-based guidance for GnRH-modulating clinical programs intended for endometriosis management. This included developing an estrogen suppression target expected to provide symptomatic relief with minimal BMD loss and to evaluate end points and study durations supportive of efficient development decisions. An existing multiscale model of calcium and bone was adapted to include systematic estrogen pharmacologic effects to describe estrogen concentration-related effects on BMD. A logistic regression fit to patient-level data from three clinical GnRH agonist (nafarelin) studies described the relationship of estrogen with endometrial-related pain. Targeting estradiol between 20 and 40 pg/ml was predicted to provide efficacious endometrial pain response while minimizing BMD effects.

Bone density in adolescents treated with a GnRH agonist and add-back therapy for endometriosis

STUDY OBJECTIVE

To evaluate the bone density of adolescents with endometriosis treated with a GnRH-agonist and "add-back" therapy with norethindrone acetate.

DESIGN

Retrospective chart review.

SETTING

Pediatric gynecology clinic at a tertiary care center.

PARTICIPANTS

36 adolescents, ages 13 to 21 years, with endometriosis.

MAIN OUTCOME MEASURES

Bone mineral density (BMD, g/cm(2)) by dual energy x-ray absorptiometry (DXA); BMD Z-scores of hip and spine.

RESULTS

The mean BMD Z-score at the total hip was -0.24 +/- 1.0, with a range of -2.4 to 1.7. At this site, 6 subjects had a BMD Z-score between -1.0 and -2.0 SD, while 2 had a Z-score < or = -2.0 SD. The mean BMD Z-score at the lumbar spine was 0.55 +/- 1.1, with a range of -2.8 to 1.4. At the spine, 11 subjects had a BMD Z-score between -1.0 and -2.0 SD, while 3 had a Z-score < or = -2.0 SD. There was no correlation noted between duration of therapy with the GnRH-agonist plus add-back and BMD at the hip or spine.

CONCLUSION

BMD at the hip was normal in most adolescents with endometriosis who were receiving a GnRH-agonist plus add-back therapy with norethindrone acetate. Almost one third of subjects exhibited skeletal deficits at the spine. These data suggest that BMD should be carefully monitored in adolescents receiving treatment with GnRH agonists.

Effect of raloxifene on bone mineral density in premenopausal women at increased risk of breast cancer

CONTEXT

Raloxifene is a promising breast cancer prevention agent in postmenopausal women at increased risk for breast cancer. The effects of raloxifene in premenopausal women are unknown.

OBJECTIVE

We evaluated the effect of raloxifene in premenopausal women at increased risk for breast cancer on bone mineral density (BMD).

DESIGN

This was a phase II clinical trial.

SETTING

This study was conducted at an academic medical center.

PARTICIPANTS

Thirty-seven premenopausal women at increased risk for breast cancer enrolled in the trial. Thirty subjects began treatment and 27 were evaluable.

INTERVENTION

Raloxifene (60 mg daily) and elemental calcium (500 mg daily) were given for 2 yr. Subjects were followed up off medications for 1 yr.

MAIN OUTCOME MEASURE

The primary end point was the intrasubject percent change in BMD at 1 yr measured by dual-energy x-ray absorptiometry.

RESULTS

The mean baseline lumbar spine density was 1.027 g/cm(2). Lumbar spine density decreased 2.3% at 1 yr (P < 0.00001) and 3.5% at 2 yr (P < .00001). Percent change from yr 2 to 3 was +1.4%. The mean baseline total hip bone density was 0.905 g/cm(2). Total hip density decreased 0.3% at 1 yr and 1.0% at 2 yr (P = 0.033). Percent change from yr 2 to 3 was +1.7%.

CONCLUSIONS

Raloxifene use is associated with a decrease in BMD in premenopausal women at increased risk for breast cancer. The clinical significance of this decrease is unknown and is attenuated with stopping raloxifene.

Treatment of endometriosis with a decreasing dosage of a gonadotropin-releasing hormone agonist (nafarelin): a pilot study with low-dose agonist therapy ("draw-back" therapy)

OBJECTIVE

To evaluate the efficacy of half-dose GnRH agonist therapy for endometriosis.

DESIGN

Prospective, longitudinal pilot study.

SETTING

Osaka University Hospital.

PATIENT(S)

Patients with symptomatic endometriosis.

INTERVENTION(S)

Fifteen patients were randomized to receive either full-dose nafarelin treatment (200 microgram b.i.d.) for 24 weeks (n = 7) or full-dose nafarelin treatment for 4 weeks followed by half-dose nafarelin treatment (200 microgram daily) for 20 weeks (n = 8).

MAIN OUTCOME MEASURE(S)

Clinical symptoms and the results of physical examinations. Serum E(2) and carcinoma antigen 125 (CA125) levels, lipid profiles, and urinary levels of the N-telopeptide of type I collagen. Bone mineral density of the lumbar spine.

RESULT(S)

Subjective and objective manifestations of endometriosis were decreased to a similar extent in both study groups. Adverse effects were markedly reduced with half-dose administration. In the half-dose group, the mean serum E(2) level was significantly suppressed by 4 weeks of treatment with full-dose nafarelin and remained at approximately 30 pg/mL with half-dose nafarelin. Loss of bone mineral density was significantly less with half-dose treatment.

CONCLUSION(S)

Half-dose administration of nafarelin after pituitary down-regulation with full-dose nafarelin ("draw-back" therapy) is a new protocol for the treatment of endometriosis that is effective and associated with fewer adverse effects.