Heterotopic ovarian allotransplantation in a caprine model: Effects of implant site on morphological parameters

This study aimed to investigate a new implantation site (intra-auricular subcutaneous - IA) compared to intramuscular (IM) in the cervical portion (cervical splenius muscle) of the neck for ovarian transplantation in goats. Morphological aspects of the implant, follicular activation and morphology, and type I and III collagen deposits of the transplanted tissue were evaluated. Four fragments of the ovarian cortex were allotransplanted at the IA and IM sites in all goat recipients and recovered 7 (IA-7; IM-7) or 15 (IA-15; IM-15) days later and submitted to histological analysis. Two fragments/animal were separated for the fresh control (FC) group. There was a higher percentage of normal and developing primordial follicles at the IA-7 site (P < 0.05) compared to the other treatments, with similar values to the fresh control. Type I and III collagen fibers differed between the groups (P < 0.05), showing a considerable decrease in type I collagen fibers at the IA-7 site compared to the FC. However, the IM-7 and IA-15 sites showed higher values of type I collagen fibers, showing similarity to the FC. Therefore, we conclude that the IA site in goats is an effective site for ovarian tissue transplantation, as it is easily accessible, low invasive and has presented satisfactory rates of morphology and follicular activation.

Ovarian tissue transplantation ameliorates osteoporosis and dyslipidaemia in ovariectomised mice

BACKGROUND

Ovarian insufficiency frequently renders postmenopausal women susceptible to osteoporosis and dyslipidaemia. Postmenopausal transplant women are at a higher risk developing osteoporosis and dyslipidaemia due to the concomitant application of glucocorticoids and immunosuppressants after solid organ transplantation. Thus, this study aimed to explore the feasibility of ovarian tissue transplantation (OTT) as an alternative to Hormone replacement therapy (HRT) for postmenopausal women with solid organ transplant needs.

RESULTS

Sixty mice were randomly divided into four groups: sham operation, ovariectomised (OVX group), ovariectomy plus oestrogen (E₂ group), and ovariectomy plus OTT (OTT group). The inhibin levels in the OTT group were increased and the follicle stimulating hormone and luteinizing hormone were suppressed to normal levels, which could not be achieved in the E₂ group. The femoral bone mineral density in the OTT group was significantly increased than the E₂ group (P < 0.05), and the probability of fracture was reduced by 1.4-2.6 times. Additionally, the high-density lipoprotein cholesterol levels were higher in the OTT group than in the E₂ group and the triglyceride levels were lower in the OTT group than in the E₂ group (P < 0.05).

CONCLUSION

OTT not only achieves certain endocrine effects by participating in the regulation of the hypothalamic-pituitary-ovarian feedback control loop, but also ameliorates osteoporosis and dyslipidaemia, which may be an alternative to traditional HRT for postmenopausal women with solid organ transplant needs.

Ovarian tissue features assessed in bovine fetuses after vitrification and xenotransplantation procedures

Cryopreservation and transplantation of ovarian tissue are proposed methods for the restoration of endocrine function and reproductive potential. Therefore, this study aimed to evaluate the effects of vitrification and xenotransplantation on follicle viability, activation, stromal cell integrity, vascularization, and micronuclei formation. Bovine fetal ovaries were fragmented and assigned to the following groups: Fresh control (FC), ovarian fragments immediately fixed; Vitrified control (VC), ovarian fragments vitrified; Vitrified xenotransplanted (VX), ovarian fragments vitrified and xenotransplanted; and Fresh xenotransplanted (FX), ovarian fragments xenotransplanted. Ovarian fragments were grafted in female BALB/c mice and recovered after 14 days. Follicular viability was preserved (P >  0.05) in VC group. The rate of developing follicles was greater (P <  0.05) in the FX group compared to other groups. Follicular density was higher (P <  0.05) in the VC group than the FC, VX, and FX groups. A decrease (P <  0.05) of stromal cell density was recorded after vitrification (VC vs. FX). Blood vessel density decreased in VC, VX, and FX groups compared with the FC group, and blood vessel density was correlated with follicular viability (positively; P =  0.07) and developing follicles (negatively; P <  0.001). Both vitrification and xenotransplantation groups (VC, VX, and FX) had a greater (P <  0.05) number of cells with one MN compared to the FC group. In summary, our findings showed that both vitrification and xenotransplantation modified blood vessel, follicular and stromal cell densities, follicular viability and activation, and micronuclei formation in ovarian tissue.

Regenerative Medicine Approaches in Bioengineering Female Reproductive Tissues

Diseases, disorders, and dysfunctions of the female reproductive tract tissues can result in either infertility and/or hormonal imbalance. Current treatment options are limited and often do not result in tissue function restoration, requiring alternative therapeutic approaches. Regenerative medicine offers potential new therapies through the bioengineering of female reproductive tissues. This review focuses on some of the current technologies that could address the restoration of functional female reproductive tissues, including the use of stem cells, biomaterial scaffolds, bio-printing, and bio-fabrication of tissues or organoids. The use of these approaches could also be used to address issues in infertility. Strategies such as cell-based hormone replacement therapy could provide a more natural means of restoring normal ovarian physiology. Engineering of reproductive tissues and organs could serve as a powerful tool for correcting developmental anomalies. Organ-on-a-chip technologies could be used to perform drug screening for personalized medicine approaches and scientific investigations of the complex physiological interactions between the female reproductive tissues and other organ systems. While some of these technologies have already been developed, others have not been translated for clinical application. The continuous evolution of biomaterials and techniques, advances in bioprinting, along with emerging ideas for new approaches, shows a promising future for treating female reproductive tract-related disorders and dysfunctions.

History, Evolution and Current State of Ovarian Tissue Auto-Transplantation with Cryopreserved Tissue: a Successful Translational Research Journey from 1999 to 2020

The loss of fertility and early menopause are common after gonadotoxic therapies and radical pelvic surgery. The strategy of ovarian tissue cryopreservation and auto-transplantation was introduced to prevent this significant quality of health issue. Ovarian transplantation with cryopreserved tissue has gone through remarkable evolution in the last 20 years. In this review, we detail the history and evolution of ovarian transplantation with cryopreserved tissue from its origins to the present. Ovarian cryopreservation and transplantation approach was first tested with animal models. The approach was then validated in human ovarian xenografting models before being applied to patients in pioneering clinical studies. The first orthotopic and heterotopic approaches to ovarian transplantation was developed by Oktay et al. who reported the first successful restoration of ovarian function with these approaches beginning in 2000 with first embryo development in 2004. Controversy remains on when the first live birth occurred after orthotopic ovarian transplantation with cryopreserved tissue as the patient was ovulating with elevated progesterone levels in the case reported in 2004; first live birth is likely to be the one reported by Meirow et al. in 2005. Nevertheless, the technique has evolved to reach a level where most recent live birth rates are exceeding 35% and the procedure is no longer considered experimental by many.

Heterotopic ovarian allotransplantation in goats: Preantral follicle viability and tissue remodeling

An appropriate implantation site favors angiogenesis and avoids ovarian tissue damage after tissue grafting. The objective of this study was to evaluate the effects of intramuscular (IM) and subcutaneous (SC) sites for ovarian grafts in goats by evaluating follicular morphology and activation, preantral follicle and stromal cell densities, tissue DNA fragmentation, collagen types I and III depositions, and graft revascularizations. Ovarian cortical tissue was transplanted in IM or SC sites and recovered 7 or 15 days post-transplantation. There was a greater percentage of developing follicles and lesser follicular and stromal cell densities in all grafted tissues as compared to ovarian tissues of the control group. The stromal cell density and percentage of normal follicles were positively associated. At 15 days post-transplantation, tissues at the SC and IM sites had similar amounts of DNA fragmentation and type III collagen content. In contrast, tissues at the SC, as compared with IM site, had greater abundances of collagen type I. Furthermore, there was a positive association between collagen type I and percentage of morphologically normal follicles post-transplantation. In addition to a marked decrease in follicular density 15 days post-transplantation in ovarian grafts at the SC and IM sites, low percentages of normal follicles and follicular activation were observed similarly in both transplantation sites. There were also positive associations of stromal cell density and abundance of type I collagen fibers with the percentage of intact follicles in grafted ovarian tissues.

In vivo transplantation of 3D encapsulated ovarian constructs in rats corrects abnormalities of ovarian failure

Safe clinical hormone replacement (HR) will likely become increasingly important in the growing populations of aged women and cancer patients undergoing treatments that ablate the ovaries. Cell-based HRT (cHRT) is an alternative approach that may allow certain physiological outcomes to be achieved with lower circulating hormone levels than pharmacological means due to participation of cells in the hypothalamus-pituitary-ovary feedback control loop. Here we describe the in vivo performance of 3D bioengineered ovarian constructs that recapitulate native cell-cell interactions between ovarian granulosa and theca cells as an approach to cHRT. The constructs are fabricated using either Ca++ or Sr++ to crosslink alginate. Following implantation in ovariectomized (ovx) rats, the Sr++-cross-linked constructs achieve stable secretion of hormones during 90 days of study. Further, we show these constructs with isogeneic cells to be effective in ameliorating adverse effects of hormone deficiency, including bone health, uterine health, and body composition in this rat model.

Morphometric characteristics of preantral and antral follicles and expression of factors involved in folliculogenesis in ovaries of adult baboons (Papio anubis)

PURPOSE

Baboons are commonly utilized as an animal model for studies of human reproduction. However, folliculogenesis in this species has not been fully documented. The aim of this study was to assess follicle morphometry and expression of essential proteins involved in folliculogenesis in baboons.

METHODS

Ovaries were recovered from four adult baboons and processed for histological evaluation and immunohistochemical analyses. Follicle proportion, follicle and oocyte diameter, theca layer thickness, number of granulosa cells, and follicle density were calculated. Immunohistochemical staining was also carried out for connexin 43 (Cx43), aromatase, and zona pellucida 3 (ZP3).

RESULTS

A total of 2221 follicles were counted and measured. Proportions of primordial, primary, secondary, small antral, and large antral follicles were 49, 26, 23, 1, and 1 %, respectively. The increase in follicle diameter was due not only to the increase in oocyte diameter but also to granulosa cell proliferation. Almost all antral follicles were positive for Cx43 (89.8 %), aromatase (84.8 %), and ZP3 (100 %). Most secondary follicles were positive for Cx43 (65 %) and ZP3 (64.5 %), and some primary follicles were positive only for Cx43. No primordial follicles stained positive in any of these immunohistochemical analyses. Only antral follicles showed aromatase activity.

CONCLUSIONS

On the basis of these results, we can conclude that folliculogenesis in baboons appears to be similar to that in humans, and this animal therefore constitutes a valuable model.

Coconut water solutions for the preservation of spleen, ovary, and skin autotransplants in rats

BACKGROUND

The purpose of this study was to evaluate the efficacy of coconut water in the preservation of spleen, ovary, and skin autotransplantations in rats.

METHODS

Fifty female Wistar rats were divided randomly into 5 groups on the basis of the following tissue graft preservation solutions: group 1, lactated Ringer's; group 2, Belzer's solution; group 3, mature coconut water; group 4, green coconut water; and group 5, modified green coconut water. In group 5, the green coconut water solution was modified to obtain the same electrolyte composition as Belzer's solution. The spleen, ovaries, and a skin fragment were removed from each animal, stored for 6 hours in one of the solutions, and then re-implanted. The recoveries of tissue functions were assessed 90 days after surgery by means of spleen scintigraphy and blood tests. The implanted tissues were collected for histological analyses.

RESULTS

Higher immunoglobulin G levels were observed in the animals of group 5 than in the animals of group 1. Differences in follicle-stimulating hormone levels were observed between groups 1 and 2 (P < .001), between groups 4 and 2 (P = .03), and between groups 5 and 2 (P = .01). The spleen scintigraphy results did not differ among the groups. The ovarian tissue was better preserved in the mature coconut water group (P < .007).

CONCLUSIONS

Solutions containing coconut water allowed for the preservation of the spleen, ovaries, and skin for 6 hours, and the normal functions of these tissues were maintained in rats.

Preliminary study of coconut water for graft tissues preservation in transplantation

OBJECTIVE: to verify the effectiveness of coconut water in preserving tissues for transplant. METHODS: Fifty male Wistar rats were randomly distributed in five groups, according to the following preservation solutions for tissue grafts: Group 1: Lactated Ringer; Group 2: Belzer solution; Group 3: mature coconut water; Group 4: green coconut water; Group 5: modified coconut water. In Group 5, the green coconut water has been modified like the Belzer solution. From each animal we harvasted the spleen, ovaries and skin of the back segment. These tissues were preserved for six hours in one of the solutions. Then, the grafts were reimplanted. The recovery of the function of the implanted tissues was assessed 90 days after surgery, by splenic scintigraphy and blood exame. The implanted tissues were collected for histopathological examination. RESULTS: The serum levels did not differ among groups, except for the animals in Group 5, which showed higher levels of IgG than Group 1, and differences in relation to FSH between groups 1 and 2 (p <0.001), 4 and 2 (p = 0.03) and 5 and 2 (p = 0.01). The splenic scintigraphy was not different between groups. The ovarian tissue was better preserved in mature coconut water (p <0.007). CONCLUSION: the coconut water-based solutions preserves spleen, ovary, and rat skin for six hours, maintaining their normal function.

Recent advances in oocyte and ovarian tissue cryopreservation and transplantation

Options for preserving fertility in women include well-established methods such as fertility-sparing surgery, shielding to reduce radiation damage to reproductive organs, and emergency in-vitro fertilisation after controlled ovarian stimulation, with the aim of freezing embryos. The practice of transfering frozen or thawed embryos has been in place for over 25 years, and today is a routine clinical treatment in fertility clinics. Oocytes may also be frozen unfertilised for later thawing and fertilisation by intracytoplasmic sperm injection in vitro. In recent years, oocyte cryopreservation methods have further developed, reaching promising standards. More than 1000 children are born worldwide after fertilisation of frozen and thawed oocytes. Nevertheless, this technique is still considered experimental. In this chapter, we focus on options for fertility preservation still in development that can be offered to women. These include freezing of oocytes and ovarian cortex and the transplantation of ovarian tissue.

Viability and function of the cryopreserved whole rat ovary: comparison between slow-freezing and vitrification

OBJECTIVE

To investigate four different protocols for cryopreservation of the whole rat ovary with intact vasculature to evaluate whether differences exist in post-thawing viability of the ovary after either vitrification or slow freezing.

DESIGN

Experimental study.

SETTING

Obstetrics and gynecology department.

ANIMAL(S)

Immature Sprague-Dawley female rats.

INTERVENTION(S)

Ovaries were isolated with the vascular tree intact up to the bifurcation of the abdominal aorta and were subsequently cannulated. The ovaries were flushed with increasing concentrations of the cryoprotectant dimethyl sulfoxide (DMSO) to either 1.5 or 7 M. The ovaries underwent cryopreservation by vitrification or passive slow freezing.

MAIN OUTCOME MEASURE(S)

After thawing, the ovaries were subjected to neutral red viability staining to assess the density of viable small follicles and for long-term (48 hours) incubation evaluation of steroid secretion, histology, and apoptosis assay.

RESULT(S)

The follicular viability was decreased in both vitrification groups and in the slow-freezing group with the high concentration of DMSO, as compared with fresh controls. Estradiol levels in the incubation medium followed the same pattern. Light microscopy revealed well-preserved morphology in all groups after 48 hours' incubation. Apoptosis was increased in both vitrified and cryopreserved ovaries.

CONCLUSION(S)

We have developed a new method that can be used in basic studies to improve cryopreservation protocols. Our initial findings suggest that a moderate concentration of the cryoprotectant DMSO is superior to a high DMSO concentration for both vitrification and slow freezing.