Age-Associated Metabolic and Morphologic Changes in Mitochondria of Individual Mouse and Hamster Oocytes

Background: In human oocytes, as in other mammalian ova, there is a significant variation in the pregnancy potential, with approximately 20% of oocyte-sperm meetings resulting in pregnancies. This frequency of successful fertilization decreases as the oocytes age. This low proportion of fruitful couplings appears to be influenced by changes in mitochondrial structure and function. In this study, we have examined mitochondrial biogenesis in both hamster (Mesocricetus auratus) and mouse (Mus musculus) ova as models for understanding the effects of aging on mitochondrial structure and energy production within the mammalian oocyte. Methodology/Principal Findings: Individual metaphase II oocytes from a total of 25 young and old mice and hamsters were collected from ovarian follicles after hormone stimulation and prepared for biochemical or structural analysis. Adenosine triphosphate levels and mitochondrial DNA number were determined within individual oocytes from young and old animals. In aged hamsters, oocyte adenosine triphosphate levels and mitochondrial DNA molecules were reduced 35.4% and 51.8%, respectively. Reductions of 38.4% and 44% in adenosine triphosphate and mitochondrial genomes, respectively, were also seen in aged mouse oocytes. Transmission electron microscopic (TEM) analysis showed that aged rodent oocytes had significant alterations in mitochondrial and cytoplasmic lamellae structure. Conclusions/Significance: In both mice and hamsters, decreased adenosine triphosphate in aged oocytes is correlated with a similar decrease in mtDNA molecules and number of mitochondria. Mitochondria in mice and hamsters undergo significant morphological change with aging including mitochondrial vacuolization, cristae alterations, and changes in cytoplasmic lamellae

Oxidative stress in pregnancy and fertility pathologies

Oxidative stress designates the state of imbalance between reactive oxygen species (ROS) production and antioxidant levels. In a healthy placenta, there is an increase in ROS production, due to formation of new tissues and inherent metabolism, but this is balanced by higher levels of antioxidants. However, this balance is lost in some situations, with a consequent increase in oxidative stress levels. Oxidative stress has been implicated in several placental disorders and pregnancy pathologies. The present review intends to summarize what is known about the relationship between oxidative stress and well-known pregnancy disorders

Dietary antioxidant supplementation did not affect declining sperm function with age in the mouse but did increase head abnormalities and reduced sperm production

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The role of CD40 and CD40L in bone mineral density and in osteoporosis risk: A genetic and functional study.

En este trabajo se estudió la asociación a densidad mineral ósea (DMO) de 15 polimorfismos (SNPs) en los genes CD40 y CD40L (N= 779 mujeres) y la funcionalidad de esta asociación a través de la expresión génica dependiente de alelos de CD40 y CD40L en leucocitos (PBLs) y en osteoblastos humanos (OBs). Se realizaron estudios sobre la tasa de transcripción in vitro dependiente de alelos y sobre la metilación de CpG en el promotor del gen. Se confirmó la asociación del SNP rs116535 de CD40L con DMO lumbar. Para CD40, las mujeres TT para SNP rs1883832 mostraron tendencia a tener niveles más bajos de osteoprotegerina. En cuanto a la funcionalidad, detectamos un desequilibrio alélico para rs1883832 siendo el alelo C el más expresado en OBs y en PBLs. Finalmente, describimos una metilación diferencial en el promotor CD40 entre mujeres de DMO alta en comparación con las de DMO baja