Summary

Puberty blockers (drugs that pause puberty) are often called a reversible pause, but little is known about their effect on the testicles. Mayo Clinic researchers examined tissue stored from children having surgery to preserve fertility. All 16 born-male patients with gender dysphoria in their tissue bank had taken puberty blockers. Treated children's tissue showed mild to severe shrinking of the sperm-making tubes; one 12-year-old on a blocker plus oestrogen had 59% of tubes completely shrunken. Detailed cell tests on one 14-year-old after more than four years on blockers found sperm-forming cells stuck at an early stage, and computer models judged the tissue to be like a child's before puberty. The authors say this raises 'a potential concern' about full reversibility. It is an early, unchecked signal: few treated patients, mixed drugs, no follow-up after stopping, no fertility measure.

Key findings

• 메이오 클리닉의 아동 고환 조직 은행 환자 87명 중 16명(18%)이 성별 불쾌감이 있었습니다. 16명 모두 사춘기 차단제를 복용했고, 9명(56%)은 생식 능력 보존 수술 당시 복용 중이었습니다.
• ‘사춘기 차단제’로 분류된 약에는 진짜 차단제(류프로라이드, 히스트렐린, 트립토렐린)뿐 아니라 에스트로겐과 다른 호르몬 약(메드록시프로게스테론, 스피로노락톤)도 포함되었으며 3~52개월 동안 복용했습니다. 수술 시 평균 연령은 12.5세였습니다.
• 성별 불쾌감이 있는 환자는 모두 사정을 원하지 않거나 할 수 없었기 때문에 정자 시료를 주는 대신 조직을 제거하는 수술을 택했습니다. 치료받은 9명 중 2명은 검사 시 고환 이상이 있었습니다.
• 암이 없는 기증자 19명에서 기증자당 약 50개 세관을 살펴보니, 세관 안의 세포 밀도는 치료받지 않은 아동에서는 나이에 따라 늘었지만 치료받은 아동에서는 나이에 따른 변화가 없었습니다. 차단제와 에스트로겐을 14개월 복용한 12세 한 명은 세관의 59%가 완전히 위축되어 있었고 작은 칼슘 침착이 있었습니다.
• 14세 한 명의 치료 52개월 이상 후 단일 세포에 대한 상세한 유전자 검사(세포 11,199개, 공개 자료와 합쳐 130,100개)에서 정자 형성 세포의 90% 넘게가 초기 단계에서 멈춰 있었고, 발달 중인 정자를 돌보는 지지 세포에서도 비정상적인 상태가 발견되었습니다.
• 단 10명(사춘기 전 아동 5명, 청년 5명)으로 훈련한 컴퓨터 모델은 치료받은 14세의 조직이 사춘기 전 아동의 것과 같다고 판단했습니다. 저자들 스스로 훈련 집단이 작은 것이 큰 약점이라고 말합니다.
• 저자들은 위축과 미성숙 세포가 완전한 가역성과 향후 생식 능력에 대한 ‘잠재적 우려를 제기한다’고 결론짓습니다. 이 연구는 중단 후 회복을 검사하지도, 생식 능력을 측정하지도 않았습니다.

Abstract

Spermatogonial stem cell (SSC) acquisition of meiotogenetic state during puberty to produce genetically diverse gametes is blocked by drugs collectively referred as 'puberty blocker' (PB). Investigating the impact of PB on juvenile SSC state and function is challenging due to limited tissue access and clinical data. Herein, we report largest clinically annotated juvenile testicular biorepository with all children with gender dysphoria on chronic PB treatment highlighting shift in pediatric patient demography in US. At the tissue level, we report mild-to-severe sex gland atrophy in PB treated children. We developed most extensive integrated single-cell RNA dataset to date (>100K single cells; 25 patients), merging both public and novel (52 month PB-treated) datasets, alongside innovative computational approach tailed for germ cells and evaluated the impact of PB and aging on SSC. We report novel constitutional ranges for each testicular cell type across the entire age spectrum, distinct effects of treatments on prepubertal vs adult SSC, presence of spermatogenic epithelial cells exhibiting post-meiotic-state, irrespective of age, puberty status, or PB treatment. Further, we defined distinct effects of PB and aging on testicular cell lineage composition, and SSC meiotogenetic state and function. Using single cell data from prepubertal and young adult, we were able to accurately predict sexual maturity based both on overall cell type proportions, as well as on gene expression patterns within each major cell type. Applying these models to a PB-treated patient that they appeared pre-pubertal across the entire tissue. This combined with the noted gland atrophy and abnormalities from the histology data raise a potential concern regarding the complete 'reversibility' and reproductive fitness of SSC. The biorepository, data, and research approach presented in this study provide unique opportunity to explore the impact of PB on testicular reproductive health.

Conclusion

The authors report mild-to-severe testicular tubule atrophy in puberty-blocker-treated children and an immature, prepubertal-like profile in the testis of a patient treated for more than 52 months. They conclude that, combined with the gland atrophy and histological abnormalities, this raises 'a potential concern regarding the complete reversibility and reproductive fitness' of spermatogonial stem cells. They also report rare post-meiotic (spermatid-like) cells in prepubertal tissue, irrespective of age, puberty status or treatment. They say the biorepository, data and research approach 'provide unique opportunity to explore the impact of PB on testicular reproductive health.'