Aspects of human uterine creatine metabolism during the menstrual cycle and at term pregnancy†.

Creatine metabolism likely contributes to energy homeostasis in the human uterus, but whether this organ synthesizes creatine and whether creatine metabolism is adjusted throughout the menstrual cycle and with pregnancy are largely unknown. This study determined endometrial protein expression of creatine-synthesizing enzymes arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT), creatine kinase (CKBB), and the creatine transporter (SLC6A8) throughout the menstrual cycle in fertile and primary infertile women. It also characterized creatine metabolism at term pregnancy, measuring aspects of creatine metabolism in myometrial and decidual tissue.

The Spiny Mouse-A Menstruating Rodent to Build a Bridge From Bench to Bedside.

Menstruation, the cyclical breakdown of the uterine lining, is arguably one of evolution's most mysterious reproductive strategies. The complexity and rarity of menstruation within the animal kingdom is undoubtedly a leading contributor to our current lack of understanding about menstrual function and disorders. In particular, the molecular and environmental mechanisms that drive menstrual and fertility dysregulation remain ambiguous, owing to the restricted opportunities to study menstruation and model menstrual disorders in species outside the primates.

Good things come to those who mate: analysis of the mating behaviour in the menstruating rodent, Acomys cahirinus.

Background: The Egyptian spiny mouse (Acomys cahirinus) is the only known rodent to exhibit true, human-like menstruation and postpartum ovulation, and is an important new model for reproductive studies. Spiny mice do not produce a visible copulatory plug, and calculation of gestational age is therefore restricted by the need to use mated postpartum dams. The current inefficient method of monitoring until parturition to provide a subsequent estimate of gestational age increases study duration and costs.

Reproductive aging and menopause-like transition in the menstruating spiny mouse (Acomys cahirinus).

Study Question: Does the naturally menstruating spiny mouse go through menopause?

Summary Answer: Our study is the first to show a natural and gradual menopausal transition in a rodent.

What Is Known Already: Age-related depletion of the human ovarian reserve (OvR) leads to menopause, the permanent cessation of menstruation and reproduction. Current rodent models of menopause are inappropriate for inferences of the human condition, as reproductive senescence is abrupt or induced through ovariectomy.

Postpartum ovulation and early pregnancy in the menstruating spiny mouse, Acomys cahirinus.

Egyptian spiny mice are the only known species to have human-like menstruation and a postpartum ovulation. Unfortunately, no endocrine or morphological evidence has been provided for a postpartum ovulation in spiny mice, and while later stages of pregnancy have been well studied, early events including embryo implantation and spiral artery remodelling have not been reported. This study compared the sex steroid endocrinology and reproductive tract morphology of dams at eight timepoints (n = 40) postpartum to determine the timing of ovulation and the timing and invasiveness of embryo implantation in A.

A human-based assisted reproduction protocol for the menstruating spiny mouse, Acomys cahirinus.

The Egyptian or Common spiny mouse (A. cahirinus) is the first rodent species to show human-like menstruation and spontaneous decidualisation. We consider from these, and its other, human-like characteristics that this species will be a more useful and appropriate small animal model for human reproductive studies.

Creatine metabolism in the uterus: potential implications for reproductive biology.

Creatine is an amino acid derivative synthesized from arginine, glycine and methionine. It serves as the substrate for the creatine kinase system, which is vital for maintaining ATP levels in tissues with high and fluctuating energy demand. There exists evidence that the creatine kinase system operates in both the endometrial and myometrial layers of the uterus.

Pseudopregnancy and reproductive cycle synchronisation cannot be induced using conventional methods in the spiny mouse (Acomys cahirinus).

The menstruating spiny mouse is the first rodent identified to exhibit natural spontaneous decidualisation, cyclical endometrial shedding and regeneration. While the spiny mouse shares several primate-like characteristics in its reproductive biology, it has not been established whether pseudopregnancy can be induced or if its cycles can be synchronised as in non-human mammals. Here we describe attempts to induce pseudopregnancy and synchronisation of menstrual cycles (i.

Monkeys, mice and menses: the bloody anomaly of the spiny mouse.

The common spiny mouse (Acomys cahirinus) is the only known rodent to demonstrate a myriad of physiological processes unseen in their murid relatives. The most recently discovered of these uncharacteristic traits: spontaneous decidual transformation of the uterus in virgin females, preceding menstruation. Menstruation occurring without experimental intervention in rodents has not been documented elsewhere to date, and natural menstruation is indeed rare in the animal kingdom outside of higher order primates.

Altered exploratory behaviour and increased food intake in the spiny mouse before menstruation: a unique pre-clinical model for examining premenstrual syndrome.

Study Question: Does the newly discovered menstruating spiny mouse exhibit behavioural and metabolic changes in correlation with premenstrual phases of the menstrual cycle?

Summary Answer: This is the first report of cycle variability in the exploratory and interactive behaviour, and food consumption in menstruating spiny mice, and demonstrates that physiological changes are also dependent on within-subject variation.

What Is Known Already: Premenstrual syndrome (PMS) is a prominent cyclic disorder that affects millions of women worldwide. More than 70% of women endure symptoms of impending menstruation, such as bloating, abdominal cramping and nausea to some degree.

Characterization of human-like menstruation in the spiny mouse: comparative studies with the human and induced mouse model.

Study Question: Is the newly discovered menstruating rodent, the spiny mouse, a valid model for studying endometrial morphology and menstruation?

Summary Answer: Our study is the first to demonstrate a primate-like pattern of natural menstruation in a rodent, with decidualization, spiral arteriole remodeling and piece-meal endometrial shedding.

What Is Known Already: The spiny mouse has a naturally occurring menstrual cycle. This unique feature has the potential to reduce the heavy reliance on primates and provide a more appropriate small animal model for menstrual physiology research.

A missing piece: the spiny mouse and the puzzle of menstruating species.

We recently discovered the first known menstruating rodent. With the exception of four bats and the elephant shrew, the common spiny mouse () is the only species outside the primate order to exhibit menses. There are few widely accepted theories on why menstruation developed as the preferred reproductive strategy of these select mammals, all of which reference the evolution of spontaneous decidualisation prior to menstrual shedding.

First evidence of a menstruating rodent: the spiny mouse (Acomys cahirinus).

Background: Advances in research relating to menstruation and associated disorders (eg, endometriosis and premenstrual syndrome) have been hindered by the lack of an appropriate animal model. Menstruation, the cyclical shedding of the decidualized endometrium in the absence of pregnancy, is believed to be limited to 78 higher-order primates (human beings and Old World monkeys), 4 species of bat, and the elephant shrew. This represents only 1.