MTHFR (methylenetetrahydrofolate reductase: EC 1.5.1.20) SNPs (single-nucleotide polymorphisms) and homocysteine in patients referred for investigation of fertility.

PURPOSE: MTHFR, one of the major enzymes in the folate cycle, is known to acquire single-nucleotide polymorphisms that significantly reduce its activity, resulting in an increase in circulating homocysteine. Methylation processes are of crucial importance in gametogenesis, involved in the regulation of imprinting and epigenetic tags on DNA and histones. We have retrospectively assessed the prevalence of MTHFR SNPs in a population consulting for infertility according to gender and studied the impact of the mutations on circulating homocysteine levels. METHODS: More than 2900 patients having suffered at least two miscarriages (2 to 9) or two failed IVF/ICSI (2 to 10) attempts were included for analysis of MTHFR SNPs C677T and A1298C. Serum homocysteine levels were measured simultaneously. RESULTS: We observed no difference in the prevalence of different genetic backgrounds between men and women; only 15% of the patients were found to be wild type. More than 40% of the patients are either homozygous for one SNP or compound heterozygous carriers. As expected, the C677T SNP shows the greatest adverse effect on homocysteine accumulation. The impact of MTHFR SNPs on circulating homocysteine is different in men than in women. CONCLUSIONS: Determination of MTHFR SNPs in both men and women must be seriously advocated in the presence of long-standing infertility; male gametes, from MTHFR SNPs carriers, are not exempted from exerting a hazardous impact on fertility. Patients should be informed of the pleiotropic medical implications of these SNPs for their own health, as well as for the health of future children.

Zinc concentrations in serum and follicular fluid during ovarian stimulation and expression of Zn2+ transporters in human oocytes and cumulus cells.

Serum and follicular fluid zinc concentrations were investigated in patients undergoing assisted reproductive treatment. No correlation was found between zinc and oestradiol concentrations in serum. At the time of oocyte retrieval, zinc concentrations in follicular fluid were significantly lower than serum concentrations (P<0.0001). The expression of the two families of zinc transporters, ZnT and ZiP, as well as the metal regulatory transcription factors, MTF1 and 2, and metallothioneins, which are both involved in regulatory aspects of zinc transport, was assayed in cumulus cells and in germinal-vesicle oocytes. Most of the zinc transporters, metallothioneins and metal regulatory transcription factor are expressed in oocytes and not in cumulus cells. This may indicate an important role for zinc, in particular with potential linking to genome stability during early embryonic development. In contrast, cumulus cells seem to be at the end of their life's journey, with weak expression of transcriptional activity linked to cellular housekeeping.

Supporting the One-Carbon Cycle Restores Ovarian Reserve in Subfertile Women: Absence of Correlation with Urinary Bisphenol A Concentration.

Environmental endocrine disrupting chemicals (EDCs), including bisphenol A (BPA), induce DNA methylation errors and oxidative stress, and alter fertility. Animal studies have demonstrated that supporting the one-carbon cycle (1-CC) with appropriate dietary supplements can reduce the effects of EDCs. Anti-Mullerian hormone (AMH), a marker of ovarian functionality, has been tested in subfertile female patients, to control this hypothesis in humans. Fifty-five women with a history of 3-7 years of infertility, with at least two assisted reproductive technology (ART) treatment failures, and low serum levels of AMH were enrolled in the study. Before starting any further ART treatment, they were tested for AMH and for follicular count. A urinary control of BPA was proposed. Then a support of the 1-CC, already tested in other clinical studies, was initiated and continued for 4 months. At the end of this period, antral follicle count and serum AMH levels were re-evaluated. The AMH levels before and after treatment were compared using the Wilcoxon test (nonparametric test, non-Gaussian population). Out of the 55 patients, 35 accepted a BPA dosage in the urine. No correlation was found between BPA and serum AMH concentrations. Forty-nine patients followed the full treatment with 1-CC supplements, which resulted in increased AMH levels, independent of initial AMH levels and maternal age (in the range studied), p = 0.0001. Eight patients spontaneously conceived ongoing pregnancies within 3 months, at the end of the protocol. A support of the 1-CC can partly alleviate metabolic derangements induced by environment, as observed in animal models, and improve endocrine background in women.

Preliminary study on the role of the human IZUMO gene in oocyte-spermatozoa fusion failure.

We studied the IZUMO gene 9 coding exons sequence in four groups of patients including those with fertilization failure by conventional IVF. We observed in our populations two combinations of four polymorphisms that appeared to be preferentially linked (CGG-CG and TAA-TT) without any significant difference between different genotype repartitions.

Clinical adaptation of the sperm ubuquitin tag immunoassay (SUTI): relationship of sperm ubiquitylation with sperm quality in gradient-purified semen samples from 93 men from a general infertility clinic population.

BACKGROUND: The proteolytic chaperone peptide ubiquitin accumulates in defective human spermatozoa. Immunodetection of ubiquitin in human sperm samples correlates with semen quality and male fertility. METHODS: Semen samples from 93 men from couples seeking infertility treatment were separated on a PureSperm density gradient and screened by immunofluorescence microscopy with anti-ubiquitin antibodies. The percentage of spermatozoa with head ubiquitylation was recorded and compared with clinical semen evaluation and embryo development data after IVF or ICSI. Subjects were divided into the following four groups based on the initial clinical diagnosis of the couples; group 1, male factor; group 2, idiopathic infertility; group 3, female infertility with neither partner having children previously; and group 4, female infertility with male partners having children from previous relationships. RESULTS: The percentage of sperm with ubiquitylated heads remaining after PureSperm separation in the respective groups was 4.0% (male factor), 2.5% (idiopathic infertility), 0.7% (female infertility and presumed fertile male) and 0.9% (female infertility with established fertile male). Negative correlations between sperm ubiquitin and several parameters reflective of embryo development after assisted fertilization were found within the male factor group. CONCLUSIONS: Use of this simplified ubiquitin-based sperm quality assay is feasible in a clinical environment. Since the gradient separation does not completely deplete the defective spermatozoa, the modified light microscopic sperm ubiquitin tag immunoassay could add a new level of stringency to the selection of human spermatozoa for ICSI.

Two fast methods for detection of Y-microdeletions.

OBJECTIVE: To test two recently available commercial kits: the new Promega Y Chromosome Deletion Detection System 2.0 kit and the Bird-Set kits (Y Chromosome UE and Extension). DESIGN: A comparative technical study. SETTING: Male infertility clinic. PATIENT(S): Twelve various Y chromosome microdeleted patients were included in the present study: two AZFa deleted, two AZFb deleted, four AZFb+c deleted, three AZFc deleted, and one AZF a+b+c deleted. INTERVENTION(S): DNA samples were tested with both the Promega kit and the Bird-Set kits. MAIN OUTCOME MEASURE(S): Electrophoresis and analysis comparison on a bioanalyzer. RESULT(S): Both kits (Promega 2.0 and Bird Y Chromosome UE) confirmed the 12 Y deletions. Both kits (Bird Extension and Promega 2.0) were able to determine the length of the 12 microdeletions with various differences. The new Promega 2.0 kit was considerably improved, with the addition of two sequenced tag sites (STS) in AZFa (sY86 and sY84) and the deletion of some (sY239 and sY153) but not all supernumerary inadequate STS. CONCLUSION(S): The two new commercially available kits use two different protocols to detect Y chromosome microdeletions. The Promega kit is a one-step diagnostic test. The Bird diagnostic test uses a two-step protocol. Both kits offer relevant methods such as standardization and ready-to-use mixes. However, both kits need further evaluation under routine conditions using nontested DNA samples.

Multicenter quality control for the detection of hepatitis C virus RNA in seminal plasma specimens.

The discrepant results available in the literature about the presence of hepatitis C virus (HCV) RNA in seminal plasma of men chronically infected by this agent are related, at least in part, to the molecular techniques used and particularly to the wide range of protocols dedicated to RNA extraction. In order to evaluate these protocols and to standardize the method of detection of HCV RNA in this fluid, a panel of coded specimens was tested blindly in 12 French laboratories; it included 14 seminal plasma specimens and four water controls spiked with HCV RNA ranging from 10 to 20000 IU/ml and two HCV-negative seminal plasma specimens. The extraction step was performed according to methods using either silica beads (NucliSens [Organon Teknika S.A., Fresnes, France]; RNA viral kit [Qiagen, Courtaboeuf, France]) or guanidinium thiocyanate (Amplicor HCV assay; Roche Diagnostics, Meylan, France), preceded or not by a centrifugation of the seminal plasma. For the amplification step, all the laboratories performed the same reverse transcription-PCR technique (Amplicor HCV Cobas assay). The percentage of correct results ranged from 53.3 to 100, the poorest results being obtained when no centrifugation step preceded the Amplicor extraction protocol. The rate of correct results was significantly higher in laboratories using a preliminary centrifugation of the specimen (P = 0.034 by chi-square test). By contrast, the overall number of correct results was not correlated to the initial volume of sample used for the test. These results allowed us to validate standardized techniques adapted to the performance of this test on a routine basis, especially in men infected with HCV and involved in programs of medically assisted reproduction.