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

• Dari 87 pasien dalam bank jaringan testis anak-anak Mayo Clinic, 16 (18%) memiliki disforia gender. Seluruh 16 orang telah memakai penghambat pubertas, dan 9 (56%) masih memakainya saat operasi penyimpanan kesuburan.
• Obat yang dihitung sebagai 'penghambat pubertas' mencakup penghambat sejati (leuprolide, histrelin, triptorelin) tetapi juga estrogen dan obat hormon lain (medroxyprogesterone, spironolactone), yang dipakai selama 3 hingga 52 bulan. Usia rata-rata saat operasi adalah 12,5 tahun.
• Semua pasien dengan disforia gender memilih operasi pengangkatan jaringan daripada memberikan sampel sperma, karena mereka tidak ingin atau tidak dapat berejakulasi. Dua dari 9 pasien yang dirawat memiliki kelainan testis saat diperiksa.
• Dengan melihat sekitar 50 saluran per donor pada 19 donor tanpa kanker, kepadatan sel dalam saluran meningkat seiring usia pada anak yang tidak dirawat, tetapi tidak menunjukkan perubahan seiring usia pada anak yang dirawat. Satu anak usia 12 tahun yang memakai penghambat plus estrogen selama 14 bulan memiliki 59% saluran yang menyusut sepenuhnya, dengan endapan kalsium kecil.
• Tes gen terperinci pada sel tunggal dari satu anak usia 14 tahun setelah lebih dari 52 bulan perawatan (11.199 sel, digabungkan dengan data publik menjadi 130.100 sel) menemukan lebih dari 90% sel pembentuk sperma terhenti pada tahap awal, dan keadaan tidak biasa pada sel penunjang yang merawat sperma yang sedang berkembang.
• Model komputer yang dilatih hanya pada 10 orang (5 anak sebelum pubertas, 5 dewasa muda) menilai jaringan anak usia 14 tahun yang dirawat itu seperti jaringan anak sebelum pubertas. Para penulis sendiri mengatakan kelompok pelatihan yang kecil adalah kelemahan utama.
• Para penulis menyimpulkan bahwa penyusutan dan sel yang belum matang itu 'menimbulkan potensi kekhawatiran' tentang pemulihan penuh dan kesuburan di masa depan. Studi ini tidak menguji pemulihan setelah berhenti maupun mengukur kesuburan.

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.'