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

• Od 87 bolnikov v banki otroškega tkiva mod klinike Mayo jih je imelo 16 (18 %) spolno nelagodje. Vseh 16 je jemalo zaviralce pubertete, 9 (56 %) pa jih je bilo nanje v času operacije ohranitve plodnosti.
• Zdravila, šteta za „zaviralce pubertete“, so vključevala prave zaviralce (leuprolid, histrelin, triptorelin), pa tudi estrogen in druga hormonska zdravila (medroksiprogesteron, spironolakton), ki so se jemala 3 do 52 mesecev. Povprečna starost ob operaciji je bila 12,5 leta.
• Vsi bolniki s spolnim nelagodjem so izbrali operacijo odstranitve tkiva namesto oddaje vzorca semenčic, ker niso hoteli ali niso mogli ejakulirati. Pri 2 od 9 zdravljenih bolnikov so ob pregledu našli nepravilnosti mod.
• Ob pregledu približno 50 cevk na darovalca pri 19 darovalcih brez raka se je gostota celic v cevkah pri nezdravljenih otrocih z leti povečevala, pri zdravljenih otrocih pa ni pokazala spremembe s starostjo. Pri enem 12-letniku na zaviralcu in estrogenu 14 mesecev je bilo 59 % cevk popolnoma skrčenih, z drobnimi kalcijevimi usedlinami.
• Podrobni genski testi na posameznih celicah enega 14-letnika po več kot 52 mesecih zdravljenja (11.199 celic, v kombinaciji z javnimi podatki 130.100 celic) so pokazali, da je več kot 90 % celic, ki tvorijo semenčice, obtičalo v zgodnji fazi, ter nenavadna stanja podpornih celic, ki skrbijo za razvoj semenčic.
• Računalniški model, učen na samo 10 osebah (5 otrocih pred puberteto, 5 mladih odraslih), je tkivo zdravljenega 14-letnika ocenil kot podobno otroškemu pred puberteto. Sami avtorji pravijo, da je majhna učna skupina velika pomanjkljivost.
• Avtorji zaključujejo, da krčenje in nezrele celice „vzbujajo potencialno skrb“ glede popolne reverzibilnosti in prihodnje plodnosti. Študija ni preizkusila okrevanja po prenehanju niti merila plodnosti.

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.'