Pharmacologic rAMH Administration Post Transplantation of Thawed Ovarian Tissue Diminishes Follicle Activation and Loss Resulting in Significantly Increased Graft Follicle Reservoir. A Non-Human Primate Study.

Introduction

Transplantation of cryo-thawed ovarian tissue results in massive loss of primordial follicle (PMF) pool that occur shortly post transplantation is accompanied with activation of follicle pool. Anti-Mullerian-Hormone (AMH) is a crucial negative regulator of PMF activation.

Aim

To determine whether c-terminal recombinant AMH (rAMH) administrated is effective in prevention of transplantation-induced PMF activation and loss, potentially improving long-term graft endocrine activity and fertility.

Materials

Frozen-thawed marmoset (n=14) ovarian cortical tissue strips (characterized by high PMF reservoir) were transplanted subcutaneously into immune-deficient castrated male mice for three days W/WO daily pharmacological rAMH IP administration. Histological analysis was conducted to assess follicle dynamics and immune staining was used to evaluate biotin-labeled rAMH, native AMH and Ki67.

Results

Extensive decrease in PMF numbers was observed in recovered grafts (3d) compared with frozen-thawed untransplanted controls (7±6.99 vs 148±37.06 PMF, p<0.01) with markedly higher proliferative activity and higher growing (GF)/PMF ratios (2.92±0.18 vs 0.10±0.03). IP Biotin-labeled rAMH was shown to reach and accumulate in grafts, rAMH normalized GF/PMF ratios (0.18±0.07). Reduced proliferative activity (KI-67) was coupled with high AMH levels in graft, resulting in increased PMF number compared with controls (56±9.88 PMF, p<0.01).

Conclusions

This non-human primate study indicates that rAMH administration adjacent to ovarian tissue transplantation can significantly rescue graft PMF pool hence potentially extend the graft’s endocrine activity and reproductive potential. These findings contribute to understanding the causes of post-transplantation follicle loss and may contribute to improvement of this fertility preservation technique.