Reproductive Lifespan In Females Research Articles

Menstrual Abnormalities and Reproductive Lifespan in Females with CKD: A Systematic Review and Meta-Analysis.

Menstrual abnormalities and shortened reproductive lifespan are associated with shorter life expectancy and higher cardiovascular and osteoporosis risk in the general population, although the magnitude of these reproductive factor irregularities in females with CKD is unclear. This systematic review and meta-analysis aimed to summarize the current knowledge regarding menstrual abnormalities and reproductive lifespan among females with CKD. A comprehensive bibliographic search (MEDLINE, Embase, and Cumulative Index to Nursing and Allied Health Literature [CINAHL]) was completed from database inception to February 2022 to identify all original articles reporting on females of reproductive age with nondialysis-dependent/nonkidney transplant CKD, dialysis-dependent CKD, or kidney transplantation and menstruation patterns, age of menarche, and/or menopause. Data extraction and study quality assessment were completed in duplicate. Random effects meta-analyses were used to derive pooled proportions estimates. Forty-six studies were identified, and 35 were meta-analyzed, stratified by KRT modality and reported outcome. Menstrual abnormalities were present in 19%-47% of patients on hemodialysis and 75% of patients on peritoneal dialysis. Kidney transplantation was associated with a 7%-30% decrease in menstrual abnormalities. Reproductive lifespan was 32 years (95% confidence interval, 30 to 34 years). Although significant heterogeneity was present, study quality ranged from fair to good, and no evidence of publication bias was noted. Menstrual abnormalities and shorter reproductive lifespan are common in females with CKD, although kidney transplantation may improve menstrual health.

MEIOK21 regulates oocyte quantity and quality via modulating meiotic recombination.

The reproductive life span of females is largely determined by the number and quality of oocytes. Previously, we identified MEIOK21 as a meiotic recombination regulator required for male fertility. Here, we characterize the important roles of MEIOK21 in regulating female meiosis and oocyte number and quality. MEIOK21 localizes at recombination sites as a component of recombination bridges in oogenesis like in spermatogenesis. Meiok21-/- female mice show subfertility. Consistently, the size of the primordial follicle pool in Meiok21-/- females is only ~40% of wild-type females because a great number of oocytes with defects in meiotic recombination and/or synapsis are eliminated. Furthermore, the numbers of primordial and growing follicles show a more marked decrease in an age-dependent manner compared with wild-type females. Further analysis shows Meiok21-/- oocytes also have reduced rates of germinal vesicle breakdown and the first polar body extrusion when cultured in vitro, indicating poor oocyte quality. Additionally, Meiok21-/- oocytes have more chromosomes bearing a single distally localized crossover (chiasmata), suggesting a possible defect in crossover maturation. Taken together, our findings indicate critical roles for MEIOK21 in ensuring the number and quality of oocytes in the follicles.

Oocyte-derived microvilli control female fertility by optimizing ovarian follicle selection in mice

Crosstalk between oocytes and surrounding somatic cells is crucial for mammalian oogenesis, but the structural mechanisms on oocytes to control female reproduction remain unknown. Here we combine endogenous-fluorescent tracing mouse models with a high-resolution live-cell imaging system to characterize oocyte-derived mushroom-like microvilli (Oo-Mvi), which mediate germ-somatic communication in mice. We perform 3D live-cell imaging to show that Oo-Mvi exhibit cellular characteristics that fit an exocrine function for signaling communication. We find that deletion of the microvilli-forming gene Radixin in oocytes leads to the loss of Oo-Mvi in ovaries, and causes a series of abnormalities in ovarian development, resulting in shortened reproductive lifespan in females. Mechanistically, we find that Oo-Mvi enrich oocyte-secreted factors and control their release, resulting in optimal selection of ovarian follicles. Taken together, our data show that the Oo-Mvi system controls the female reproductive lifespan by governing the fate of follicles.

Notch1 is crucial for decidualization and maintaining the first pregnancy in the mouse†.

The endometrium undergoes a pregnancy-delivery-repair cycle multiple times during the reproductive lifespan in females. Decidualization is one of the critical events for the success of this essential process. We have previously reported that Notch1 is essential for artificial decidualization in mice. However, in a natural pregnancy, the deletion of Notch1 (PgrCre/+Notch1f/f, or Notch1d/d) only affects female fertility in the first 30days of a 6-month fertility test, but not the later stages. In the present study, we undertook a closer evaluation at the first pregnancy of these mice to attempt to understand this puzzling phenomenon. We observed a large number of pregnancy losses in Notch1d/d mice in their first pregnancy, which led to the subfertility observed in the first 30days of the fertility test. We then demonstrated that the initial pregnancy loss is a consequence of impaired decidualization. Furthermore, we identified a group of genes that contribute to Notch1 regulated decidualization in a natural pregnancy. Gene ontogeny analysis showed that these differentially expressed genes in the natural pregnancy are involved in cell-cell and cell-matrix interactions, different from genes that have been previously identified from the artificial decidualization model, which contribute to cell proliferation and apoptosis. In summary, we determined that Notch1 is essential for normal decidualization in the mouse uterus only in the first pregnancy but not in subsequent ones.

Reproductive pattern of an exploited dusky grouper <i>Epinephelus marginatus</i> (Lowe 1834) (Pisces: Serranidae) population in the western Mediterranean

The reproductive parameters of the dusky grouper, Epinephelus marginatus, in the Balearic Islands (western Mediterranean) were studied with a histological analysis of specimens caught by artisanal and recreational spear fisheries. The histological examination of the gonads showed that the dusky grouper spawning season extends from late spring to the end of summer with clear spawning peaks in July and August. The monthly variation of the hepatosomatic index (HSI) and the Le Cren condition index suggests that reserves for gonad development were obtained from the energy stored in the liver before spawning. Females reach maturation at 49 cm total length (TL) and 6 years, and transitional individuals start to occur before all females are matured. Males were the largest and oldest specimens but females were also present in the largest and oldest classes and there was a large sex, size and age overlap in the population. The fecundity data showed that the dusky grouper is a determinate spawner with asynchronous oocyte development. Potential fecundity ranged between 65 thousand and 8 million oocytes in females from 39 to 92 cm TL and from 6 to 42 years of age, with a mean relative fecundity of 334 x 103 oocytes kg-1. Females spawn an average of 10 batches during the spawning season, with a relative batch fecundity of 75 x 103 oocytes kg-1. Fecundity increased significantly with length, weight, age and HSI, while relative fecundity was only related to HSI. Based on the results obtained in the present study (long reproductive lifespan of females, influence of maternal attributes on fecundity and size at maturity) management measures for the species were evaluated.

Intrauterine maternal food restriction programs neuroendocrine changes that shorten the reproductive lifespan of female offspring

Prenatal stress programs HPG axis dysfunction, possibly shortening reproductive lifespan in females. We hypothesized that female rats exposed to food restriction (FR) in utero would exhibit neuroendocrine changes evident at birth, puberty and adulthood, indicating shortened reproductive lifespan. Dams were either fed ad libitum (AL) or were 50% FR from p10 to p21. At birth, hypothalamic gonadotropin releasing hormone (GnRH) and hypothalamic and ovarian estrogen receptor‐alpha (ER‐alpha) protein expression were measured by western blot. Age and body weight at puberty as well as estrous cyclicity at 8 and 10 mo. of age were observed. Rats were sacrificed at 10 mo. to examine ovarian histology and plasma hormones. At birth, hypothalamic GnRH (1±0.1 vs. 0.5±0.1, p<0.05) was decreased, and ER‐alpha was increased in the hypothalamus (1±0.4 vs. 3.2±0.7, p<0.05) but decreased in the ovary (1±0.1 vs. 0.6±0.1, p<0.05). FR rats had reduced body weight at puberty and by 10 mo. their estrous cycles had stopped. At sacrifice FR rats had decreased estradiol (17.5±1 vs. 11±2 pg/ml, p<0.05), increased luteinizing hormone (0.28±0.05 vs. 0.58±0.1 ng/ml, p<0.05) and abnormal ovarian histology, consistent early with reproductive aging. HPG axis regulation is inextricably linked to energy balance, and prenatal FR programs shortened reproductive lifespan, possibly to ensure reproduction in a potentially harsh environment.

Sex-specific strategies of dentine depletion in red deer

Worn teeth in herbivore ungulates may be related to lower efficiency in mastication and hence lower performance. However, selection should favour maximal performance in terms of body mass and reproductive capacity during reproductive lifespan, when permanent teeth are already partially worn. We hypothesize that wear rate may respond to a strategy of use of tooth materials (notably dentine), which balances instantaneous wear rate and performance against tooth preservation for future performance and reproduction. In the present study, we investigated 4151 carcasses of Iberian red deer Cervus elaphus hispanicus and show that more worn molars were not related to lower performance throughout age. By comparing between sexes, tooth wear rates were smaller in females than in males, but the relationship between tooth wear and body performance also differed between the sexes: females did not show a significant relationship between tooth wear and performance but males with more worn teeth were in general heavier and had larger antlers until senile age, when more depleted teeth were related to smaller antlers. These results reveal, for the first time, sex-specific lifetime strategies of dentine expenditure: maintenance of performance ability throughout a longer reproductive lifespan in females, compared with maximizing current performance by depleting dentine reserves within a shorter lifespan in males. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 487–497.

The structural basis of oocyte-granulosa cell communication.

The ontogeny of female germ cells in animals encompasses phases of prolonged storage, rapid growth and maturation, and mechanisms for releasing oocytes from the ovary (Wallace and Selman 1990). Ovarian follicles provide the multicellular unit for prolonged storage of oocytes both prior to and during the reproductive lifespan of females. The follicle, formed by the physical interaction of oocytes and granulosa cells, supports the rapid growth and maturation of oocytes (Canipari 1994). To accomplish this, the somatic granulosa cells surrounding the oocyte undergo periodic changes in structure and function that concurrently attend the needs of the developing oocyte and organismal reproductive cyclicity. The physical linkage between female germ cells and the ovarian soma is finally interrupted during the process of ovulation, even though in many animals the oocyte is released with somatic cells attached to the oolemma or investing extracellular matrices (Suzuki et al. 2000). Thus, from both a phylogenetic and ontogenetic perspective, oogenesis clearly involves a protracted period of contact between the oocyte and surrounding follicle cells. The morphological and physiological relevance of oocyte—granulosa cell contact in the mammalian ovary is considered below with reference to the form, composition and functions subserved by specialized structures known as transzonal projections (TZPs).

A shift toward early reproduction in an introduced herbivorous ladybird

1. In May 1971, fifteen male and thirty female overwintering adults of a thistle‐feeding ladybird Epilachna niponica were taken from the Asiu Experimental Forest of Kyoto University and introduced into the Botanical Garden of Kyoto University, 30 km south of Asiu and 10 km south of the southern limits of its distribution. The introduced population established successfully and thereafter maintained densities sufficiently high to defoliate their host plants.2. Reproductive parameters (reproductive lifespan of females, overall fecundity, and oviposition schedules) of the introduced population were compared with those of the source population 10 years after the introduction. Comparisons were made in the laboratory under five temperature regimes.3. The lifespan of females differed significantly with temperature, decreasing linearly with increasing temperature. Temperature also had a significant effect on overall fecundity for both populations; overall fecundity at 15 and 30 °C was significantly lower than that at the 20–25 °C regimes.4. The oviposition activity of the introduced population was significantly higher than that of the source population at 23 and 25 °C. The lifespan of females of the introduced population was also significantly shorter than those of the source population at 20 and 25 °C.5. The reduced lifespan and higher oviposition activity of introduced females indicate that they directed greater reproductive efforts early in their reproductive lifetime than those of the source population.

The staggerer gene curtails the reproductive life span of females.

Three studies were undertaken to investigate some features of the reproductive activity of female staggerer mice of the C57BL/6 strain. It was found that in the staggerer female, (1) vaginal opening and onset of vaginal estrous cycling were delayed; (2) the vaginal estrous cycle was irregular and characterized by abnormally prolonged diestrous and estrous phases, and (3) the reproductive life span of the mutant female was confined to a 3-month period after puberty. The abnormalities observed in sexual functions suggest a specific influence of the staggerer gene on reproductive activity.

Estimates of reproductive parameters for free-rangingAteles geoffroyi

Six and a half years of data collected on the reproductive parameters of a population of free-rangingAteles geoffroyi show the following characteristics: seasonality of births; interbirth interval of ca. 32 months; nursing by infants for more than 2 years; and reproductive life span of females continuing beyond 20 years of age. These characteristics appear to reflect adaptations to a primary resource base, ripe fruit, that is very low in protein and patchily distributed in space and time in tropical forests.