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Open access

The effect of gestational age on mitochondrial properties of the mouse placenta

Lucy A Bartho, Joshua J Fisher, Sarah L Walton, Anthony V Perkins, and James S M Cuffe

Mitochondria are organelles within the cell that generate energy, which is essential to the developing placenta. As the placenta approaches term, organelles such as mitochondria and the endoplasmic reticulum adapt to cellular stressors (e.g. oxidative stress and fluctuations in oxygen concentration) which are likely to result in the progressive decline of tissue function, known as placental ageing. This ageing phenotype may induce cellular senescence, a process whereby the cell is no longer proliferating, yet remains metabolically active. Mitochondria, endoplasmic reticulum and senescent processes are still poorly understood in the developing placenta. Therefore, a rodent ontogeny model was used to measure genes and proteins involved in mitochondrial biogenesis, antioxidant function, electron transport chain, mitophagy, dynamics and unfolded protein response in the placenta. CD-1 mouse placental samples were collected at embryonic day (E)12.5, E14.5, E16.5 and E18.5 of pregnancy for gene and protein analysis via qPCR, protein assays and Western blotting. Mitochondrial content, SDHB (complex II) and MFN2 (mitochondrial fusion) proteins were all increased throughout pregnancy, while citrate synthase activity/mitochondrial content, Tfam, Sirt3, Mfn1, TOMM20 (mitochondrial biogenesis and dynamics); Tp53(senescence); Eif2ak3, Eif4g1(endoplasmic reticulum stress);NDUFB8, UQCRC2, ATP5A (electron transport chain sub-complexes) were decreased at E18.5, compared to E12.5. Overall, mitochondria undergo changes in response to gestational progression and pathways associated with cellular ageing to facilitate adaptions in a healthy pregnancy. This data holds great promise that mitochondrial markers across pregnancy may help to establish when a placenta is ageing inappropriately.

Lay summary

Human pregnancy lasts approximately 266 days. If a baby is born early, organs may be poorly formed but if pregnancy continues past this time, stillbirth risk is increased. Gestational duration is regulated by the placenta. As the placenta approaches the end of pregnancy, it displays properties similar to tissues from aged individuals. However, it is unknown how this placental ageing contributes to pregnancy duration. This study characterised normal placental ageing by measuring properties of mitochondria in healthy placentas collected at four different gestational ages ranging from 7 days before birth to 1 day before birth of the 19-day mouse pregnancy. We found that mitochondrial number increased per cell but that a marker of mitochondrial function was reduced. Proteins that control mitochondrial number, morphology and function also changed over time. This work lays the platform to understand how placental ageing contributes to adverse pregnancy outcomes related to altered pregnancy duration.

DOI:
https://doi.org/10.1530/RAF-21-0064
Volume 3: Issue 1,
Pages:
19–29 (11 total)
Open access

Q fever and early pregnancy failure: a Scottish case–control study

Nick Wheelhouse, Sadie Kemp, Jo E B Halliday, Efstathios Alexandros Tingas, W Colin Duncan, and Andrew W Horne

Lay summary

Q fever is a bacterial disease that passes between animals and humans and causes disease in both. The disease has been associated with pregnancy complications including miscarriage. This study was undertaken to identify if Q fever exposure was correlated with miscarriage in 369 women attending a pregnancy support unit in Edinburgh. The women in the study were in two groups, the miscarriage group with 251 women who had experienced a miscarriage and a control group of 118 women who had not experienced miscarriage. Three women were found to be positive for Q fever antibodies, suggesting that they had previously been exposed to the infection and all of them were from the group who had experienced miscarriage. The study indicates that Q fever is relatively rare in women attending an urban Scottish hospital suggesting that the infection is not a major cause of miscarriage in this population. However, as Q fever antibodies could only be found in women within the miscarriage group, it suggests that the infection cannot be ruled out as a potential cause of miscarriage in individual cases.

DOI:
https://doi.org/10.1530/RAF-21-0072
Volume 3: Issue 1,
Pages:
L1–L2
Free access

Acknowledgement to reviewers

DOI:
https://doi.org/10.1530/RAF-3-A1
Volume 3: Issue 1,
Pages:
A1
Open access

Onset of normal cycles in postpartum anovulatory dairy cattle treated with kisspeptin

Chris R Burke, John R Roche, Robert P Millar, and Iain J Clarke

The efficacy of a long-acting synthetic derivative of kisspeptin (Kp) to initiate normal oestrous cycles was tested in 24 mixed-aged, Holstein-Friesian cows that were 18–25 days postpartum on the day of treatment (D0). Groups of eight cows received saline (Sal) vehicle by intramuscular injection at 8:00 and 16:00 h (Sal-Sal), Kp at 8:00 h and vehicle at 16:00 h (Kp-Sal) or Kp on both occasions (Kp-Kp). The Kp dose was 15 nmol per 60 kg body weight. The ovaries of the cows were examined daily by ultrasonography between D4 and D14. Blood samples were collected from a tail vessel at 0, 2, 4, 8, 10 and 12 h relative to the time of the first injection for luteinizing hormone (LH) and follicle-stimulating hormone assay. Additional samples were collected daily from D4 until D14 and D19, 22, 26 and 29 for progesterone assay. LH surge-like responses were observed in cows treated with Kp at 8:00 h. Ovulation was consistently induced by Kp within 48 h when a dominant ovarian follicle of at least 10 mm in diameter was observed (8/14) but in no cases (6/14) during a new wave of ovarian follicular development comprising follicles <10 mm in diameter. The subsequent ovulatory cycle was of normal length in most cases as compared with short 8– to 12-day cycles observed in spontaneously ovulating cows. We conclude that Kp treatment can induce ovulation in postpartum dairy cows, with ensuing oestrous cycles of normal length, if administered when a mature dominant follicle is present in the ovaries.

Lay summary

Cow fertility is important for efficient, profitable dairy farming. Cows that take too long after calving to become fertile are problematic. We tested a synthetically made, long-acting hormone called kisspeptin (Kp) to advance the time that cows become fertile after calving. Twenty-four dairy cows that had been calved for 3–4 weeks were used. One group of eight cows received an injection of Kp at the morning milking, another eight cows received Kp at both the morning and afternoon milking, while the last group of eight cows served as untreated controls. Kp treatment caused a desirable hormone response from the cows’ brain. Normal oestrous cycles resulted, but only when a mature follicle was present in the ovary. Further study is required to analyse whether the use of a long-acting Kp drug could be used as an effective treatment for stimulating dairy cows to become more fertile after calving.

DOI:
https://doi.org/10.1530/RAF-21-0046
Volume 3: Issue 1,
Pages:
1–8 (8 total)
Open access

Fixation in Form-Acetic allows hyaluronic acid detection in mouse ovaries

R Appeltant, B V Adeniran, and S A Williams

Lay summary

To visualise tissues to determine the presence of disease or simply to understand anatomy, it is important to preserve fresh tissue. Fixatives are chemical solutions that preserve tissues to enable microscopic evaluation. However, some fixatives introduce artefact such as shrinkage of cells. Recently, a new fixative, Form-Acetic, was developed that is superior for preserving the structure of ovary tissue and allows investigation of ovary composition. One component of the ovary is hyaluronic acid (HA), which plays a crucial role in normal ovary function and fertility. Importantly, HA is sensitive to different fixative solutions. Therefore, it is meaningful to verify whether Form-Acetic is suitable for detecting HA. In this study, adult mouse ovaries were fixed in Form-Acetic and HA was detected. All HA-containing structures in the ovary were clearly distinguished which proves that the novel fixative allows the detection of HA.

DOI:
https://doi.org/10.1530/RAF-21-0085
Volume 2: Issue 4,
Pages:
L10–L12
Open access

Retrospective cohort study on preparation regimens for frozen embryo transfer

Monique Atkinson, Jenny Crittenden, Howard Smith, and Cecilia Sjoblom

The objective of this study was to examine the pregnancy outcomes from frozen embryo transfer (FET) cycles using different endometrial preparation regimens, compared to ovulation induction with letrozole (letrozole OI). A retrospective cohort study was conducted at a fertility centre in Sydney, Australia, on 6060 FET cycles. The cycles were stratified into one of four ways to achieve endometrial preparation. These were either a natural, letrozole OI, OI with follicle-stimulating hormone (FSH OI) or a programmed cycle. The primary outcome was live birth rate (LBR) per embryo transfer. Secondary outcomes included clinical pregnancy and biochemical pregnancy rates, adverse events including miscarriage, ectopic pregnancy, stillbirth, neonatal death and multiple births. Ovarian stimulation parameters were also analysed including the time taken to reach the luteal phase and the number of blood or urine tests required for monitoring the cycle. The results of the study showed that the LBR following letrozole OI cycles was higher when compared to natural cycles (odds ratio (OR): 1.27 (1.07–1.49)) and programmed cycles (OR: 2.36 (1.67–3.34)). There was no significant difference between letrozole OI and FSH OI LBR (OR: 0.99 (0.76–1.28)). An improved LBR with letrozole OI compared to natural cycles was maintained when only women with a normal length cycle were considered (OR: 1.44 (1.10–1.89)). There was a significant reduction in miscarriage rates when letrozole OI was compared to programmed cycles (OR: 0.46 (0.26–0.83)). It was therefore concluded that the use of letrozole OI for endometrial preparation in an FET cycle may be associated with higher LBR and lower miscarriage rate, compared to using a programmed cycle.

Lay summary

Couples suffering from infertility frequently try to conceive following the transfer of an embryo which has been frozen during an in vitro fertilisation cycle. Embryos will only lead to a pregnancy if the woman’s womb lining has particular characteristics that allow it to accept the embryo. Despite the thousands of frozen embryo transfer cycles carried out across the world, it is not known how best to prepare a woman’s lining so it has these particular characteristics. This study looked at the pregnancy outcomes of 6060 cycles to compare four different ways to prepare a woman’s womb lining. These included relying on a woman’s natural menstrual cycle, or using an oral medication called letrozole, or injectable medicine called follicle-stimulating hormone, or oestrogen and progesterone hormonal medications. The comparison found that using letrozole before transfer of a frozen embryo may be associated with higher rates of a live birth for some women.

DOI:
https://doi.org/10.1530/RAF-21-0044
Volume 2: Issue 4,
Pages:
308–316 (9 total)
Open access

Is there a valid ethical objection to the clinical use of in vitro-derived gametes?

Kristian Galea

DOI:
https://doi.org/10.1530/RAF-21-0066
Volume 2: Issue 4,
Pages:
S5–S8
Open access

Nonhormonal therapy for endometriosis based on energy metabolism regulation

Hiroshi Kobayashi, Hiroshi Shigetomi, and Shogo Imanaka

Ovarian function suppression is the current pharmacotherapy of endometriosis with limited benefit and adverse effects. New therapeutic strategies other than hormonal therapy are developed based on the molecular mechanisms involved in the hypoxic and oxidative stress environments and metabolism unique to endometriosis. A literature search was performed between January 2000 and March 2021 in the PubMed database using a combination of specific terms. Endometriosis-associated metabolic changes have been organized into four hallmarks: (1) glucose uptake, (2) aerobic glycolysis, (3) lactate production and accumulation, and (4) metabolic conversion from mitochondrial oxidative phosphorylation (OXPHOS) to aerobic glycolysis. Endometriotic cells favor glycolytic metabolism over mitochondrial OXPHOS to produce essential energy for cell survival. Hypoxia, a common feature of the endometriosis environment, is a key player in this metabolic conversion, which may lead to glucose transporter overexpression, pyruvate dehydrogenase kinase 1 (PDK1) and lactate dehydrogenase kinase A (LDHA) activation, and pyruvate dehydrogenase complex inactivation. Evading mitochondrial OXPHOS mitigates excessive generation of reactive oxygen species (ROS) that may trigger cell death. Therefore, the coinactivation of LDHA and PDK1 can induce the accumulation of mitochondrial ROS by converting energy metabolism to mitochondrial OXPHOS, causing endometriotic cell death. Metabolic pattern reconstruction in endometriotic lesions is a critical factor in cell survival and disease progression. One therapeutic strategy that may avoid hormone manipulation is focused on mitigating metabolic changes that have been detected in cells/tissues from women with endometriosis.

Lay summary

The most commonly used medical therapies for endometriosis have contraceptives and other side effects associated with hormone suppression and are therefore unsuitable for women desiring pregnancy. One therapeutic strategy that may avoid hormone manipulation is focused on changing metabolic profiles that have been detected in cells/tissues from women with endometriosis. Endometriotic cells favor glycolytic metabolism over mitochondrial oxidative phosphorylation (OXPHOS) to produce essential energy for cell growth. Furthermore, the metabolic conversion from mitochondrial OXPHOS to aerobic glycolysis suppresses cell death through the reduced generation of reactive oxygen species (ROS). This unique metabolic feature of endometriosis is important for cell survival and disease progression. Thus, changing the specific metabolic switch may increase mitochondrial ROS production, causing severe oxidative stress and cell death. This review describes new treatments by changing the metabolic profiles of endometriosis.

DOI:
https://doi.org/10.1530/RAF-21-0053
Volume 2: Issue 4,
Pages:
C42–C57
Open access

Can antioxidants protect against chemotherapy in a rat spermatogonial stem cell line?

Caroline M Allen, Federica Lopes, Rod T Mitchell, and Norah Spears

Lay summary

Boys administered chemotherapy to treat cancer are at risk of damage to their healthy testicular tissue, which can lead to infertility in adulthood. Researchers are therefore investigating treatments to protect the testis during cancer treatment. Here, cells originating from rat testicles were cultured for 4 days and exposed to chemotherapy drugs with or without antioxidants for the final 2 days. Antioxidants can reduce cellular damage by inactivating toxic compounds. Here, antioxidants such as melatonin or n-acetylcysteine were tested against chemotherapy agents cisplatin, doxorubicin, or vincristine. Cultures were repeated four times, with cell survival measured at the end of culture. The antioxidants were not damaging and partially protected against cisplatin, although not doxorubicin. Surprisingly, n-acetylcysteine enhanced vincristine-induced damage. The results suggest that using antioxidants to protect the testis could have either beneficial or harmful effects when given alongside different chemotherapy drugs: this is important, considering that patients are often treated with multiple drugs.

DOI:
https://doi.org/10.1530/RAF-21-0042
Volume 2: Issue 4,
Pages:
L7–L9
Open access

Spectral binning of cervicovaginal fluid metabolites improves prediction of spontaneous preterm birth and Lactobacillus species dominance

Emmanuel Amabebe, Steven Reynolds, and Dilly O C Anumba

Lay summary

Health-promoting bacteria (lactobacilli) exist in harmony with the vaginal environment. They are the predominant vaginal bacterial species during pregnancy. However, the possibility of infection and inappropriate immune response are linked with unprompted preterm delivery (PTD). Other invasive lactobacilli can alter the chemical environment of the vagina as they seek to promote their growth. This study measured the change in concentration of biochemical compounds and predominant bacterial species in vaginal fluid that are linked to PTD. The study recruited 300 healthy pregnant women who provided vaginal fluid samples during the second trimester. The women who harboured more of Lactobacillus jensenii over Lactobacillus crispatus (both reported as health-promoting bacteria) in their vaginal fluid had less lactate and glutamate and experienced more PTD. This suggests that lactate and glutamate levels in vaginal fluid may have clinical application in identifying which Lactobacillus species is most active. These chemical biomarkers could provide quick and accurate prediction of PTD risk in clinical settings.

DOI:
https://doi.org/10.1530/RAF-21-0065
Volume 2: Issue 4,
Pages:
L4–L6