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Development of the follicular basement membrane during human gametogenesis and early folliculogenesis.

Heeren AM, van Iperen L, Klootwijk DB, de Melo Bernardo A, Roost MS, Gomes Fernandes MM, Louwe LA, Hilders CG, Helmerhorst FM, van der Westerlaken LA, Chuva de Sousa Lopes SM - BMC Dev. Biol. (2015)

Bottom Line: In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood.This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Einthovenweg 20, 2333, Leiden, ZC, The Netherlands. marijneheeren@gmail.com.

ABSTRACT

Background: In society, there is a clear need to improve the success rate of techniques to restore fertility. Therefore a deeper knowledge of the dynamics of the complex molecular environment that regulates human gametogenesis and (early) folliculogenesis in vivo is necessary. Here, we have studied these processes focusing on the formation of the follicular basement membrane (BM) in vivo.

Results: The distribution of the main components of the extracellular matrix (ECM) collagen IV, laminin and fibronectin by week 10 of gestation (W10) in the ovarian cortex revealed the existence of ovarian cords and of a distinct mesenchymal compartment, resembling the organization in the male gonads. By W17, the first primordial follicles were assembled individually in that (cortical) mesenchymal compartment and were already encapsulated by a BM of collagen IV and laminin, but not fibronectin. In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.

Conclusions: The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood. This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

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Related in: MedlinePlus

Model of ovarian cords and mesenchymal compartment organization in fetal ovaries during gonadogenesis up to early folliculogenesis. In female gonads, a specific organization in ovarian cords appear. The majority of germ cells in the first trimester ovary are early germ cells, but in the second trimester both early and more mature germ cells (morphological bigger germ cells) were present and segregated spatially in the ovary: early germ cells located closer to the surface whereas the more mature (bigger) germ cells are located in the inner part of the cortex [17]. From W17, individual primordial follicles become embedded in the mesenchymal compartment and at birth all germ cells are present as individual primordial follicles in the mesenchymal compartment which supports the further development of these follicles up to ovulation in adulthood.
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Fig8: Model of ovarian cords and mesenchymal compartment organization in fetal ovaries during gonadogenesis up to early folliculogenesis. In female gonads, a specific organization in ovarian cords appear. The majority of germ cells in the first trimester ovary are early germ cells, but in the second trimester both early and more mature germ cells (morphological bigger germ cells) were present and segregated spatially in the ovary: early germ cells located closer to the surface whereas the more mature (bigger) germ cells are located in the inner part of the cortex [17]. From W17, individual primordial follicles become embedded in the mesenchymal compartment and at birth all germ cells are present as individual primordial follicles in the mesenchymal compartment which supports the further development of these follicles up to ovulation in adulthood.

Mentions: Here, we show that basically from the time the PGCs arrive to the gonads (in both male and females), the ECM contributed to create a “germ cell” niche where the germ cells could develop their sex-specific characteristics (Figure 8). More importantly, not only in males, but also in females a specific organization in germ cell cords became apparent after immunostaining for ECM components at W10. Our results in human are in agreement with a recent study in cow [20], suggesting a higher degree of organization in female gonads and much earlier than previously thought [16]. Well-defined ovarian cords have also been described in other mammalian species, like pig and sheep [1,21].Figure 8


Development of the follicular basement membrane during human gametogenesis and early folliculogenesis.

Heeren AM, van Iperen L, Klootwijk DB, de Melo Bernardo A, Roost MS, Gomes Fernandes MM, Louwe LA, Hilders CG, Helmerhorst FM, van der Westerlaken LA, Chuva de Sousa Lopes SM - BMC Dev. Biol. (2015)

Model of ovarian cords and mesenchymal compartment organization in fetal ovaries during gonadogenesis up to early folliculogenesis. In female gonads, a specific organization in ovarian cords appear. The majority of germ cells in the first trimester ovary are early germ cells, but in the second trimester both early and more mature germ cells (morphological bigger germ cells) were present and segregated spatially in the ovary: early germ cells located closer to the surface whereas the more mature (bigger) germ cells are located in the inner part of the cortex [17]. From W17, individual primordial follicles become embedded in the mesenchymal compartment and at birth all germ cells are present as individual primordial follicles in the mesenchymal compartment which supports the further development of these follicles up to ovulation in adulthood.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4307144&req=5

Fig8: Model of ovarian cords and mesenchymal compartment organization in fetal ovaries during gonadogenesis up to early folliculogenesis. In female gonads, a specific organization in ovarian cords appear. The majority of germ cells in the first trimester ovary are early germ cells, but in the second trimester both early and more mature germ cells (morphological bigger germ cells) were present and segregated spatially in the ovary: early germ cells located closer to the surface whereas the more mature (bigger) germ cells are located in the inner part of the cortex [17]. From W17, individual primordial follicles become embedded in the mesenchymal compartment and at birth all germ cells are present as individual primordial follicles in the mesenchymal compartment which supports the further development of these follicles up to ovulation in adulthood.
Mentions: Here, we show that basically from the time the PGCs arrive to the gonads (in both male and females), the ECM contributed to create a “germ cell” niche where the germ cells could develop their sex-specific characteristics (Figure 8). More importantly, not only in males, but also in females a specific organization in germ cell cords became apparent after immunostaining for ECM components at W10. Our results in human are in agreement with a recent study in cow [20], suggesting a higher degree of organization in female gonads and much earlier than previously thought [16]. Well-defined ovarian cords have also been described in other mammalian species, like pig and sheep [1,21].Figure 8

Bottom Line: In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood.This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Einthovenweg 20, 2333, Leiden, ZC, The Netherlands. marijneheeren@gmail.com.

ABSTRACT

Background: In society, there is a clear need to improve the success rate of techniques to restore fertility. Therefore a deeper knowledge of the dynamics of the complex molecular environment that regulates human gametogenesis and (early) folliculogenesis in vivo is necessary. Here, we have studied these processes focusing on the formation of the follicular basement membrane (BM) in vivo.

Results: The distribution of the main components of the extracellular matrix (ECM) collagen IV, laminin and fibronectin by week 10 of gestation (W10) in the ovarian cortex revealed the existence of ovarian cords and of a distinct mesenchymal compartment, resembling the organization in the male gonads. By W17, the first primordial follicles were assembled individually in that (cortical) mesenchymal compartment and were already encapsulated by a BM of collagen IV and laminin, but not fibronectin. In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.

Conclusions: The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood. This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

Show MeSH
Related in: MedlinePlus