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Santos, Torcato; Dias, C. C.; Henriques, P.; Brito, R.; Barbosa, Antônio Amaral; Regateiro, Fernando; Santos, A. Almeida

doi:10.1023/a:1022630924236

Cited by 23 publications

(4 citation statements)

References 12 publications

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“…Eventually, some oocytes differentiate into parthenotes with a trophectoderm (te, Figure 12D and E), blastocoele (bc) and inner cell mass (icm) [179], similarly to some oocytes in in vitro fertilization (IVF) cultures [186]. This indicates that the OSC-derived oocytes developed in vitro are functionally similar to the mature follicular oocytes.…”

Section: Developmental Potential Of Ovarian Stem Cells In Vitromentioning

confidence: 99%

“…Some of these OSC-derived epithelial cells appear to be precursors of gradually differentiating oocytes. Spontaneous development of parthenogenetic embryos in ovarian cultures, which can also be observed during oocyte handling for standard IVF purposes [186], indicates the functional similarity of in vitro developed eggs with cultured follicular oocytes. Development of oocytes from OSC derived from ovaries with no naturally present follicles and oocytes (POF and postmenopausal women) [94,189] confirms the ability of OSC to produce new eggs in the absence of OSC niche present during neo-oogenesis in vivo .…”

Section: Developmental Potential Of Ovarian Stem Cells In Vitromentioning

confidence: 99%

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Immunoregulation of follicular renewal, selection, POF, and menopause in vivo, vs. neo-oogenesis in vitro, POF and ovarian infertility treatment, and a clinical trial

Bukovský

Caudle

2012

Reprod Biol Endocrinol

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The immune system plays an important role in the regulation of tissue homeostasis ("tissue immune physiology"). Function of distinct tissues during adulthood, including the ovary, requires (1) Renewal from stem cells, (2) Preservation of tissue-specific cells in a proper differentiated state, which differs among distinct tissues, and (3) Regulation of tissue quantity. Such morphostasis can be executed by the tissue control system, consisting of immune system-related components, vascular pericytes, and autonomic innervation. Morphostasis is established epigenetically, during morphogenetic (developmental) immune adaptation, i.e., during the critical developmental period. Subsequently, the tissues are maintained in a state of differentiation reached during the adaptation by a “stop effect” of resident and self renewing monocyte-derived cells. The later normal tissue is programmed to emerge (e.g., late emergence of ovarian granulosa cells), the earlier its function ceases. Alteration of certain tissue differentiation during the critical developmental period causes persistent alteration of that tissue function, including premature ovarian failure (POF) and primary amenorrhea. In fetal and adult human ovaries the ovarian surface epithelium cells called ovarian stem cells (OSC) are bipotent stem cells for the formation of ovarian germ and granulosa cells. Recently termed oogonial stem cells are, in reality, not stem but already germ cells which have the ability to divide. Immune system-related cells and molecules accompany asymmetric division of OSC resulting in the emergence of secondary germ cells, symmetric division, and migration of secondary germ cells, formation of new granulosa cells and fetal and adult primordial follicles (follicular renewal), and selection and growth of primary/preantral, and dominant follicles. The number of selected follicles during each ovarian cycle is determined by autonomic innervation. Morphostasis is altered with advancing age, due to degenerative changes of the immune system. This causes cessation of oocyte and follicular renewal at 38 +/-2 years of age due to the lack of formation of new granulosa cells. Oocytes in primordial follicles persisting after the end of the prime reproductive period accumulate genetic alterations resulting in an exponentially growing incidence of fetal trisomies and other genetic abnormalities with advanced maternal age. The secondary germ cells also develop in the OSC cultures derived from POF and aging ovaries. In vitro conditions are free of immune mechanisms, which prevent neo-oogenesis in vivo. Such germ cells are capable of differentiating in vitro into functional oocytes. This may provide fresh oocytes and genetically related children to women lacking the ability to produce their own follicular oocytes. Further study of "immune physiology" may help us to better understand ovarian physiology and pathology, including ovarian infertility caused by POF or by a lack of ovarian follicles with functional oocytes in aging ovaries. The observations indicating...

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Section: Developmental Potential Of Ovarian Stem Cells In Vitromentioning

confidence: 99%

Section: Developmental Potential Of Ovarian Stem Cells In Vitromentioning

confidence: 99%

Immunoregulation of follicular renewal, selection, POF, and menopause in vivo, vs. neo-oogenesis in vitro, POF and ovarian infertility treatment, and a clinical trial

Bukovský

Caudle

2012

Reprod Biol Endocrinol

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“…Recent studies reported that human unfertilized eggs undergo parthenogenetic activation in vivo and in vitro (12–13). This may contribute germ cell derived ovarian teratomas in humans.…”

Section: Discussionmentioning

confidence: 99%

Strain-specific spontaneous activation during mouse oocyte maturation

Cheng

Zhong

Latham

2012

Fertility and Sterility

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Objective To examine whether spontaneous oocyte activation is determined by genetic differences and interacted with culture environment. Design Experimental Study. Setting Temple University School of Medicine. Animals C57BL/6, DBA/2, C3H/HeJ, and A/J strains, along with reciprocal F1 hybrid female mice (5–6 weeks). Intervention(s) Immature oocytes from different mouse strains were collected and cultured in different maturation conditions including different serum, serum replacement, bovine serum albumin (BSA) and follicle stimulation hormone (FSH). Main Outcome Measure(s) The emission of first polar body, pronucleus formation, meiotic arrest, spontaneous activation, and expression of maturation regulators. Result(s) Oocytes from C57BL/6 mice display a high rate of delayed first meiotic division and spontaneous activation after the first meiotic division with in vitro maturation (IVM), and the second meiosis with in vivo maturation (VVM) following superovulation. Spontaneous activation with IVM is sensitive to culture environment. Oocytes spontaneously activated during the first meiotic division with IVM have unusual paired tetrad chromosomes with slight connections at centromeres, whereas oocytes activated in vivo display haploidization from the second meiosis. Spontaneous activation is also seen in F1 hybrid oocytes, indicating a dominant trait from C57BL/6. Delayed meiosis was associated with reduced cylcin B and securin expression. Conclusion(s) Both mouse strain and culture environment have a significant effect on the incidence of meiotic defects and spontaneous activation. Reduced expression of meiotic regulators may underlie this effect.

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“…Among all factors, exposure to cold and prolonged retention in the oviduct after animal sacrifice can significantly increase rat OSA ( Keefer and Schuetz, 1982 ; Zernicka-Goetz, 1991 ; Kito et al, 2010 ). Another widely recognized factor is postovulatory aging, which has been shown in rat ( Ben-Yosef et al, 1995 ; Chaube et al, 2007 ; Cui et al, 2012 ), golden hamster ( Sun et al, 2002 ; Jiang et al, 2015 ), and human ( Santos et al, 2003 ) to facilitate OSA ( Table 1 ). Same as other vertebrates, the two most critical kinases of cytostatic factor (CSF), maturation-promoting factor (MPF), and mitogen-activated protein kinase (MAPK), are also involved in OSA ( Tiwari et al, 2018 ).…”

Section: Mechanism and Control Of Type-1 Osamentioning

confidence: 99%

Oocyte Spontaneous Activation: An Overlooked Cellular Event That Impairs Female Fertility in Mammals

Cui

2021

Front. Cell Dev. Biol.

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In mammals, including humans, mature oocytes are ovulated into the oviduct for fertilization. Normally, these oocytes are arrested at metaphase of the second meiosis (MII), and this arrest can be maintained for a certain period, which is essential for fertilization in vivo and oocyte manipulations in vitro, such as assisted reproduction in clinics and nuclear/spindle transfer in laboratories. However, in some species and under certain circumstances, exit from MII occurs spontaneously without any obvious stimulation or morphological signs, which is so-called oocyte spontaneous activation (OSA). This mini-review summarizes two types of OSA. In the first type (e.g., most rat strains), oocytes can maintain MII arrest in vivo, but once removed out, oocytes undergo OSA with sister chromatids separated and eventually scattered in the cytoplasm. Because the stimulation is minimal (oocyte collection itself), this OSA is incomplete and cannot force oocytes into interphase. Notably, once re-activated by sperm or chemicals, those scattered chromatids will form multiple pronuclei (MPN), which may recapitulate certain MPN and aneuploidy cases observed in fertility clinics. The second type of OSA occurs in ovarian oocytes (e.g., certain mouse strains and dromedary camel). Without ovulation or fertilization, these OSA-oocytes can initiate intrafollicular development, but these parthenotes cannot develop to term due to aberrant genomic imprinting. Instead, they either degrade or give rise to ovarian teratomas, which have also been reported in female patients. Last but not the least, genetic models displaying OSA phenotypes and the lessons we can learn from animal OSA for human reproduction are also discussed.

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Abstract: Retention of the second polar body and chromosome malsegregation were observed after parthenogenetic activation, either spontaneous or induced by puromycin. This means that using parthenogenetic embryos for stem cell research will require great care and attention.

Cited by 23 publications

References 12 publications

Immunoregulation of follicular renewal, selection, POF, and menopause in vivo, vs. neo-oogenesis in vitro, POF and ovarian infertility treatment, and a clinical trial

Immunoregulation of follicular renewal, selection, POF, and menopause in vivo, vs. neo-oogenesis in vitro, POF and ovarian infertility treatment, and a clinical trial

Strain-specific spontaneous activation during mouse oocyte maturation

Oocyte Spontaneous Activation: An Overlooked Cellular Event That Impairs Female Fertility in Mammals

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