Relationship between diminished ovarian reserve and mitochondrial biogenesis in cumulus cells.

STUDY QUESTION: What part do mitochondria play in cases of diminished ovarian reserve (DOR)? SUMMARY ANSWER: Mitochondrial biogenesis in cumulus cells may be linked with impaired oocyte competence in patients with DOR. WHAT IS KNOWN ALREADY: DOR, one of the causes of infertility even in young women, is characterized by the depletion of the ovarian pool associated with a decline in oocyte competence. Mitochondria, which play a role in oocyte quality, could be involved in the pathogenesis of DOR. The study of cumulus cells offers an interesting non-invasive approach for evaluating oocyte quality and the metabolic processes on which it depends. If mitochondrial dysfunction is involved in DOR, it is likely to have an impact on the functioning of cumulus cells. STUDY DESIGN, SIZE, DURATION: This is an observational study of 74 immature oocyte-cumulus complexes retrieved from 47 women undergoing in vitro fertilization with intracytoplasmic sperm injection at the University Hospital of Angers, France, from March 2013 to March 2014. The women were divided into two groups: one group included 26 women with DOR, and the other, which included 21 women with a normal ovarian reserve (NOR), served as a control group. PARTICIPANTS/MATERIALS, SETTINGS, METHODS: The oocyte mitochondrial content and the average mitochondrial content of the cumulus cells were assessed by mitochondrial (mt)DNA quantification using a quantitative real-time PCR technique. Microfluidic-based quantitative RT-PCR assays were used to quantify the expression of 13 genes involved in mitochondrial functions such as apoptosis and antioxidant activity or in mitochondrial biogenesis. We used orthogonal partial least-squares discriminant analysis (OPLS-DA) to distinguish between the DOR group and the NOR group of patients, and an OPLS model to predict the value of the oocyte mtDNA content that could be used as a critical marker of oocyte quality. MAIN RESULTS AND THE ROLE OF CHANCE: The OPLS-DA model showed a good predictive capability (Q2 = 0.543). Using the variable importance in projection (VIP) metric we found three mitochondrial variables distinguishing the DOR group from the NOR group of patients, i.e. the oocyte mtDNA content (VIP = 0.92), the cumulus cell mtDNA content (VIP = 0.95) and the expression in cumulus cells of peroxisome proliferator-activated receptor γ coactivator 1 alpha (PPARGC-1A) (VIP = 1.10), all of which were lower in the DOR group than in the NOR group of patients. The OPLS model was able to satisfactorily predict the oocyte mtDNA content in only the NOR group of patients (Q2 = 0.506). We found four new variables positively linked to the oocyte mitochondrial mass, i.e. the cumulus cell mtDNA content (VIP = 1.19), and the expression in cumulus cells of three factors of mitochondrial biogenesis: polymerase gamma (POLG) (VIP = 2.13), optic atrophy 1 (OPA1) (VIP = 1.89) and the transcription factor associated with mitochondria (TFAM) (VIP = 1.32). LIMITATIONS, REASONS OF CAUTION: This is a descriptive study. Because of ethical concerns in human clinical practice, this study has been performed only on immature oocytes and corresponding cumulus cells, which are usually discarded during in vitro fertilization procedures. WIDER IMPLICATIONS OF THE FINDINGS: Cumulus cells may govern mitochondrial biogenesis, creating an adequate oocyte mitochondrial pool to promote embryonic development. The alteration of this process in patients with DOR may account for the impairment of oocyte quality. This suggests that some mitochondrial characteristics of cumulus cells may serve as indicators of oocyte competence and that oocyte quality may be improved by products enhancing mitochondrial biogenesis. STUDY FUNDING/COMPETING INTERESTS: This work was supported by a grant from the University Hospital of Angers, France: 'Appel d'offre interne à la recherche 2014'. TRIAL REGISTRATION NUMBER: N/A.

Mitochondrial macro-haplogroup JT may play a protective role in ovarian ageing.

This study of 200 Caucasian women shows that the distribution of the mtDNA macro-haplogroups in patients with diminished ovarian reserve (DOR) differed significantly from that of patients with normal ovarian reserve (NOR) (p=0.02). The JT macro-haplogroup was significantly under-represented in DOR patients compared with NOR patients (p=0.006) and compared with the estimated frequency of 18.8% in the general French population (p=0.0012). Our findings suggest that the risk of a prematurely depleted ovarian reserve would be three times lower for patients carrying the JT macro-haplogroup than for patients with any of the other mtDNA haplogroups (odds ratio: 0.3; 95% CI: 0.13-0.74). If these preliminary results are confirmed in larger independent studies, they should lead to the better management of infertility.

[Molecular characterization of corona radiata cells from patients with diminished ovarian reserve]. / Profil d'expression des cellules de la corona radiata chez les patientes présentant une réserve ovarienne diminuée.

OBJECTIVES: Diminished ovarian reserve (DOR) is one of the causes of infertility. In this prospective study, gene expression profiling (GEP) of corona radiata cells (CRC) was performed to identify genes deregulated in DOR patients. PATIENTS AND METHODS: Microarray-based GEP of CRC isolated from eight women undergoing IVF was performed to identify genes differentially expressed between patients with normal ovarian reserve and DOR patients. Microfluidic-based quantitative RT-PCR assay were used to validate selected transcripts on 40 independent patients. RESULTS: Forty-eight transcripts were differentially expressed, including CXXC5 and FOXC1 down regulated in DOR, as well as CTGF, FSTL3, PTGS2 and SOCS2 up regulated in DOR. According to these transcripts, two DOR patients'subgroups (DOR Gr1 and Gr2) were identified. In DOR Gr2 patients, CITED2, CTGF, GAS-1, IRS2, PTGS2, SOCS2, VCAN were expressed at significantly higher levels, and CXXC5, FOXC1, GBP2 and ZMIZ1 at significantly lower level. Eleven of those genes are transcriptional targets of Estrogens and higher baseline oestradiol levels were observed in DOR Gr2 patients (P<0.006). DISCUSSION AND CONCLUSION: Twelve genes deregulated in CRC of DOR patients were identified, which could be involved in DOR pathogenesis. The distinction of a particular subgroup of DOR patients suggests the possibility of deregulation of estrogen response genes.

Measuring cervical length with ultrasound: evaluation of the procedures and duration of a learning method.

OBJECTIVE: To evaluate the learning curve and principal learning steps for a novice ultrasound operator to master the technique for measuring cervical length by transvaginal ultrasound. SUBJECTS AND METHODS: The study involved asymptomatic patients with a singleton pregnancy between 21 and 38 weeks attending for a routine ultrasound scan. Two operators new to cervical ultrasound including one with experience in transvaginal gynecological ultrasound were assessed during their training. After an initial lecture session on the technique of cervical measurement, the trainees had one or two supervised practice sessions, validated by two interobserver agreement studies with 30 patients at a time; these compared the level of agreement between trainer and trainee throughout. Five examinations were performed in the first practice session; a second session was planned if the trainee could not perform all five examinations alone satisfactorily, in agreement with four quality criteria predefined for good cervical measurements. The second session lasted until five consecutive examinations could be performed adequately without the trainer's aid. Agreement between the two operators was assessed by intraclass correlation coefficient (ICC). The ICCs were compared with Fisher's Z transformation. RESULTS: Of the 150 patients included, 2.7% gave birth before term. The trainee with no experience in transvaginal ultrasound required two practice sessions; none of the five ultrasound scans performed in the first session was correct. In the second session, 18 consecutive ultrasound examinations were necessary to obtain five consecutive adequate results. During interobserver studies with the trainer, the ICC progressed from 0.43 in the first study to 0.64 in the second and 0.77 in the third (P = 0.049 between the first and third studies). The trainee with experience in transvaginal ultrasound required only one practice session. The ICC increased from 0.73 to 0.85 in the two interobserver studies with the trainer. CONCLUSIONS: Measurement of cervical length by transvaginal ultrasound examination is a technique that can be learnt rapidly. While roughly 23 supervised ultrasound scans appear necessary for an operator with no experience in transvaginal ultrasound, substantially fewer are required for an operator already familiar with this approach for other indications.

Vitamin A status in the institutionalized elderly. Critical analysis of four evaluation criteria: dietary vitamin A intake, serum retinol, relative dose-response test (RDR) and impression cytology with transfer (ICT).

Infraclinical vitamin A deficiencies may be health-threatening for elderly people, yet they are difficult to assess unequivocally in this population. In this study, we evaluate the vitamin A status of an elderly institutionalized population (49 subjects, 83.6 +/- 6.1 years of age), by examining four different criteria: the dietary vitamin A intake, the retinol concentration in serum, the relative dose-response test and the impression cytology with transfer. The incidence of infra-clinical deficiencies was estimated to be 55% by examining dietary vitamin A intake, 21% by using the RDR test, 6% by the ICT and 2% from serum retinol values. These variations are not due to the choice of threshold values for each of the methods, yet rather to poor correlations between the results given by these methods. Canonical correlation analyses indicate that some parameters related to retinol secretion from the liver, including Zn, prealbumin and retinol-binding protein, can affect individual patient response towards the different methods. Validation of the RDR test in this elderly population was not successful because of poor reproducibility and moderate correction of RDR-detected vitamin A deficiencies by vitamin A supplementation. The method chosen for the determination of vitamin A status in elderly people must be carefully evaluated to account for possible age-related changes in the patient response to the method employed. In the institutionalized elderly population examined in this study, we observed a low vitamin A intake, whereas serum retinol and ICT are within normal ranges and while RDR test's responses appear too variable to draw any conclusion.