'An ounce of prevention is worth a pound of cure': the case for and against GnRH-agonist for fertility preservation

The late effects of cancer treatment have recently gained a worldwide interest among reproductive endocrinologists, oncologists, and all health-care providers, and the protection against iatrogenic infertility caused by chemotherapy assumes a high priority. Here, we summarize the case for and against using GnRH-agonist for fertility preservation and minimizing chemotherapy-induced gonadotoxicity. The rationale and philosophy supporting its use is that preventing premature ovarian failure (POF) is preferable to treating it, following the dictum: 'an ounce of prevention is worth a pound of cure'. Despite many publications on this subject, there are many equivocal issues necessitating summary. Until now, 20 studies (15 retrospective and 5 randomized, controlled trials) have reported on 1837 patients treated with GnRH-a in parallel to chemotherapy, showing a significant decrease in POF rate in survivors versus 9 studies reporting on 593 patients, with results not supporting GnRH-a use. Patients treated with GnRH-a in parallel to chemotherapy preserved their cyclic ovarian function in 91% of cases when compared with 41% of controls, with a pregnancy rate of 19-71% in the treated patients. Furthermore, seven meta-analyses have concluded that GnRH-a are beneficial and may decrease the risk of POF in survivors. However, controversy still remains regarding the efficiency of GnRH-a in preserving fertility. Since not all the methods involving fertility preservation are unequivocally successful and safe, these young patients deserve to be informed of all the various modalities to minimize gonadal damage and preserve ovarian function and future fertility. Combining several methods for a specific patient may increase the odds for minimally invasive fertility preservation.

Preserving fertility when choosing chemotherapy regimens - the role of gonadotropin-releasing hormone agonists

INTRODUCTION

The late effects of cancer treatment have recently gained a worldwide ubiquitous interest among reproductive endocrinologists, oncologists, and all health care providers. Despite many publications on this subject, there are many equivocal issues necessitating summary. The case for and against using GnRH-agonist for fertility preservation is summarized with the rationale that preventing ovarian failure may be better than treating it.

AREAS COVERED

We searched Medline in the last 10 years using terms: 'fertility preservation', 'female chemotherapy', 'Gonadotropin-releasing hormone (GnRH) analogues', 'GnRH agonists' 'gonadotoxicity', and 'cancer treatment'. We included mainly publications from the past 7 years, but did not exclude previous, commonly referenced publications. Here, we summarize the various methods available for fertility preservation and minimizing chemotherapy induced gonadotoxicity.

EXPERT OPINION

Until now, 20 studies (15 retrospective and 5 randomized controlled trial) have reported on 2038 patients treated with GnRH-a in parallel to chemotherapy, showing a significant decrease in premature ovarian failure (POF) rate in survivors versus 8 studies reporting on 509 patients, with negative results. Patients treated with GnRH-a in parallel to chemotherapy preserved their cyclic ovarian function in 91% of cases as compared to 41% of controls, with a pregnancy rate of 19 - 71% in the treated patients. Furthermore, over 10 recent meta-analyses have concluded that GnRH-a are beneficial and may decrease the risk of POF in survivors. Because most of the methods involving ovarian or egg cryopreservation are not yet clinically established and unequivocally successful, these young patients deserve to be informed with all the various modalities to minimize gonadal damage and preserve ovarian function and future fertility. Combining the various modalities for a specific patient may increase the odds of preservation of future fertility.

Recent advances in bone regeneration using adult stem cells

Bone is a highly vascularized tissue reliant on the close spatial and temporal association between blood vessels and bone cells. Therefore, cells that participate in vasculogenesis and osteogenesis play a pivotal role in bone formation during prenatal and postnatal periods. Nevertheless, spontaneous healing of bone fracture is occasionally impaired due to insufficient blood and cellular supply to the site of injury. In these cases, bone regeneration process is interrupted, which might result in delayed union or even nonunion of the fracture. Nonunion fracture is difficult to treat and have a high financial impact. In the last decade, numerous technological advancements in bone tissue engineering and cell-therapy opened new horizon in the field of bone regeneration. This review starts with presentation of the biological processes involved in bone development, bone remodeling, fracture healing process and the microenvironment at bone healing sites. Then, we discuss the rationale for using adult stem cells and listed the characteristics of the available cells for bone regeneration. The mechanism of action and epigenetic regulations for osteogenic differentiation are also described. Finally, we review the literature for translational and clinical trials that investigated the use of adult stem cells (mesenchymal stem cells, endothelial progenitor cells and CD34⁺ blood progenitors) for bone regeneration.

Effect of primary human endometrial stromal cells on epithelial cell receptivity and protein expression is dependent on menstrual cycle stage

BACKGROUND

Successful implantation requires a receptive endometrium. We hypothesized that effects of endometrial stromal cells (ESC) on epithelial cell receptivity and trophoblast-endometrium interaction are menstrual cycle dependent.

METHODS

An endometrial in vitro 3D co-culture model of primary human ESC with the endometrial epithelial cell line (RL95-2) was constructed. Co-cultures were prepared using primary ESC from biopsies taken before the window of implantation (ESCbw) and during the window of implantation (ESCw), on cycle days 10-17 and 19-23, respectively. RL95-2 served as a constant parameter upon which the influence of ESC from different phases of the cycle was investigated. proMMP-2 (MMP, matrix metalloproteinase) and proMMP-9 secretion was tested in response to progesterone. Progesterone receptor B (PR-B) and plexin B1 protein expression and mRNA levels were investigated using immunofluorescence and RT-PCR, respectively.

RESULTS

Progesterone increased proMMP-2 secretion in primary ESCbw (P = 0.0046) but decreased proMMP-2 and proMMP-9 secretion in ESCw (P < 0.0005). In the presence of ESCbw, JAR spheroid attachment rate to overlying RL95-2 cells was decreased (P < 0.0001), whereas in the presence of ESCw, attachment rate was unchanged. Progesterone treatment restored epithelial cell receptivity in co-culture with ESCbw (P = 0.00004). A correlation between spheroid attachment rate and plexin B1 mRNA level was observed (P = 0.01). PR-B protein and mRNA level were influenced by the interplay between RL95-2 and stromal cells.

CONCLUSION

The effects of human primary ESC on epithelial cell receptivity and trophoblast-endometrium interaction depended upon whether the ESC were taken before or during the window of implantation.

Human amniotic epithelial cells cultured in substitute serum medium maintain their stem cell characteristics for up to four passages

BACKGROUND AND OBJECTIVES

The common applied culture medium in which human amniotic epithelial cells (hAECs) maintain their stem cell characteristics contains fetal calf serum (FCS) and thus is not compatible with possible future clinical applications due to the danger of animal derived pathogens. To overcome this problem, we replaced FCS with serum substitute supplement, a serum substitute used in the in vitro fertilization for embryo development, in the common applied culture medium and cultured hAECs in this substitute serum medium (SSM).

METHODS AND RESULTS

Purity validation and characterization of freshly isolated and cultured hAECs was assessed through the expression of stem cell specific markers by RT-PCR (gene expression), by immunofluorescence staining and FACS (protein expression). Furthermore, karyotype was performed at passage four in order to exclude possible chromosome anomalies in hAECs cultured in SSM. The differentiation potential of hAECs into the cardiomyogenic lineage was tested through cardiac Troponin T expression by immunohistochemistry. hAECs cultured in SSM maintained expression of all the major pluripotent genes Sox-2, Oct-4 and Nanog as well as the expression of the embryonic stem cell specific surface antigens SSEA-4, SSEA-3 and TRA-1-60 over four passages. Using cardiac differentiation medium containing 10% serum substitute supplement, hAECs differentiated into cardiac troponin T expressing cells.

CONCLUSIONS

We can conclude that, hAECs maintain their stem cell characteristics when cultured in SSM for up to 4 passages. This makes possible future clinical applications of these cells more feasible.

Human amniotic epithelial cells differentiate into cells expressing germ cell specific markers when cultured in medium containing serum substitute supplement

BACKGROUND

Human amniotic epithelial cells (hAECs) maintain the plasticity of pregastrulation embryonic cells, having the potential to differentiate into all three germ layers. The potential of these cells to differentiate into cells expressing germ cell specific markers has never been described before.

METHODS

In the present study, hAECs were cultured in medium containing serum substitute supplement (SSS). Gene and protein expression of germ cell and oocyte specific markers was assessed by reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence staining and flow activated cell sorter analysis (FACS) in hAECs at different time points during the differentiation into cells expressing germ cell specific markers.

RESULTS

When cultured with SSS, already at passage 1, hAECs start to express the germ cell specific genes C-KIT, DAZL, VASA and ZP3 and at passage 5 large round cells, resembling oocytes, appeared. The cells express the germ cell specific marker DAZL, the oocyte specific markers GDF9 and ZP3 and the meiosis specific markers DMC1 and SCP3 at the protein level.

CONCLUSIONS

From our preliminary results we can conclude that hAECs have the potential to differentiate into cells expressing germ cell specific markers.

Ovarian Stem Cells-the Pros and Cons

The potential for postnatal de novo oogenesis in mammals and in humans has become very controversial in the fields of reproductive science and biology. Historically, it has been thought that females of most mammalian species lose the ability to produce oocytes at birth. A contemporary understanding of stem cell biology together with novel experimental methods has challenged the model of a prenatal fixed ovarian primordial follicle pool that declines with age. Researchers have suggested replenishment of post-natal oocytes by germ-line stem cells (GSCs). According to this theory, GSCs produce oocytes and primordial follicles throughout the lifetime of the adult female. This review describes recent approaches supporting the revolutionary idea of de novo oogenesis in mammals and humans of reproductive-age and provides counter arguments from opponents of this novel and innovative concept.

Adult stem cells in the use of jaw bone regeneration: current and prospective research

Concomitant to the increased use of dental implants to replace lost dentition, there is a growing need to regenerate atrophic jaw bone to allow dental implant placement. Current surgical techniques for jaw bone augmentation share several limitations, such as operator sensitivity and relatively low predictability and high morbidity rates. Therefore, alternative treatment approaches have been developed in the field of tissue engineering. Bone tissue engineering integrates the use of different scaffolds, growth factors, and stem cells. This method aims to induce bone augmentation of large bone defects by mimicking biologic processes that occur during embryogenesis. This review will present available sources for adult stem cells, the rationale for using stem cells for bone regeneration, and recent studies that use mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) to induce bone augmentation.