RESUMEN
With increasing age in women, the ovarian function declines, which leads to decreased follicle generation, declined female fertility and age-related diseases ultimately. Female germline stem cells are epithelial cells existing on the ovarian surface, which can divide into new stem cells symmetrically and differentiate into germ cells and granulosa cells asymmetrically. The discovery of female germline stem cells brings much hope for the post-natal renewal of oocytes and solving female infertility problems. Ovarian germline stem cell niche in which female germline stem cells live is the surrounding microenvironment which plays an essential role in maintaining the function of female germline stem cells. Many factors including nutrition supply, protein, cytokines and signaling pathways can control the biological characters of female germline stem cells, and also influence their proliferation and differentiation. This paper reviewed the knowledge about the influencing factors and regulatory mechanisms of the function of ovarian germline stem cell niche.
RESUMEN
With increasing age in women, the ovarian function declines, which leads to decreased follicle generation, declined female fertility and age-related diseases ultimately. Female germline stem cells are epithelial cells existing on the ovarian surface, which can divide into new stem cells symmetrically and differentiate into germ cells and granulosa cells asymmetrically. The discovery of female germline stem cells brings much hope for the post-natal renewal of oocytes and solving female infertility problems. Ovarian germline stem cell niche in which female germline stem cells live is the surrounding microenvironment which plays an essential role in maintaining the function of female germline stem cells. Many factors including nutrition supply, protein, cytokines and signaling pathways can control the biological characters of female germline stem cells, and also influence their proliferation and differentiation. This paper reviewed the knowledge about the influencing factors and regulatory mechanisms of the function of ovarian germline stem cell niche.
RESUMEN
Los cambios fisiológicos con la edad, son consecuencia de cambios sistémicos generales producidos por el envejecimiento, entre los que se destacan cambios a nivel de los mecanismos de defensa relacionados con las especies reactivas del oxígeno (ROS) y alteraciones de la microcirculación. Los cambios evolutivos ováricos con la edad, se deben esencialmente a una depleción de la población folicular, la cual al disminuir por debajo de 1000 folículos, hace perder la capacidad del ovario de ciclar en forma normal, con la consiguiente disminución en los niveles de esteroides circulantes y sus efectos secundarios en los órganos efectores. Asociado a la disminución de la población folicular, se producen cambios en la calidad ovocitaria, los cuales determinan la disminución progresiva de la fertilidad en mujeres mayores de 35 años. Entre los cambios más frecuentes se observan aumento de aneuploidias, disfunciones mitocondriales, cambios de la microcirculación y disminución de la capacidad defensiva sobrelas ROS, entre otros.
The physiological changes with age are the consequence of systemic general changes produced by aging, where changes of the defense mechanisms related to ROS and microcirculation alterations are highlighted. The evolutive changes produced by age in the ovary are related to the follicular depletion. When the ovarian follicle population decrease below 1000 follicles, the ovary loses its capacityto cycle normally. As a consequence, the levels of circulating steroids diminished, producing negatives effects on secondary steroidal organs. In association with the follicular depletion, there are changes in oocyte quality, which determine the progressive diminution of fertility in women older than 35 years. The most frequent changes observed are an increase of the aneuploidies, mitochondrial dysfunction, microcirculation changes and a diminution of the defense capacity to ROS among others.