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

• 在梅奥诊所儿童睾丸组织库的87名患者中，16人（18%）有性别焦虑。16人全部使用过青春期阻断剂，其中9人（56%）在保留生育能力手术时仍在使用。
• 被算作“青春期阻断剂”的药物包括真正的阻断剂（亮丙瑞林、组氨瑞林、曲普瑞林），也包括雌激素和其他激素类药物（甲羟孕酮、螺内酯），使用时间为3至52个月。手术时的平均年龄为12.5岁。
• 所有有性别焦虑的患者都选择通过手术取出组织，而不是提供精液样本，因为他们不想或无法射精。9名接受治疗的患者中有2人在检查时发现睾丸异常。
• 对19名无癌症的捐献者每人观察约50条小管，未治疗儿童的小管细胞密度随年龄增加，而接受治疗的儿童则没有随年龄变化。一名使用阻断剂加雌激素14个月的12岁患者，有59%的小管完全萎缩，并有微小的钙沉积。
• 对一名使用治疗超过52个月的14岁患者的单个细胞进行的详细基因检测（11,199个细胞，与公开数据合并后为130,100个细胞）发现，超过90%的生精细胞停留在早期阶段，并且滋养发育中精子的支持细胞处于异常状态。
• 一个仅用10人（5名青春期前儿童，5名年轻成人）训练的计算机模型，判断这名接受治疗的14岁患者的组织类似青春期前儿童的组织。作者自己也说，训练组很小是一个主要弱点。
• 作者的结论是，萎缩和不成熟的细胞“引发了对完全可逆性和未来生育能力的潜在担忧”。该研究没有检验停药后的恢复情况，也没有测量生育能力。

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.'