Pierre Jouannet

Decline in Semen Quality among Fertile Men in Paris during the Past 20 Years

Background Several studies have suggested a population-wide decline in the quality of semen over the past 50 years, but clear evidence of decreasing semen quality in recent decades is lacking. Methods From 1973 through 1992 we measured the volume of seminal fluid, the sperm concentration, and the percentages of motile and morphologically normal spermatozoa in 1351 healthy fertile men. The data on the semen samples were collected at one sperm bank in Paris. The data in each calendar year were analyzed as a function of the year of donation, the age of each patient, the year of birth, and the duration of sexual abstinence before semen collection. Results There was no change in semen volume during the study period. The mean concentration of sperm decreased by 2.1 percent per year, from 89 ×106 per milliliter in 1973 to 60×106 per milliliter in 1992 (P<0.001). During the same period the percentages of motile and normal spermatozoa decreased by 0.6 percent and 0.5 percent per year, respectively (both P<0.001). ...

Specific epigenetic alterations of IGF2 - H19 locus in spermatozoa from infertile men

DNA methylation marks, a key modification of imprinting, are erased in primordial germ cells and sex specifically re-established during gametogenesis. Abnormal epigenetic programming has been proposed as a possible mechanism compromising male fertility. We analysed by pyrosequencing the DNA methylation status of 47 CpGs located in differentially methylated regions (DMRs), the DMR0 and DMR2 of the IGF2 gene and in the 3rd and 6th CTCF-binding sites of the H19 DMR in human sperm from men with normal semen and patients with teratozoospermia (T) and/or oligo-astheno-teratozoospermia (OAT). All normal semen samples presented the expected high global methylation level for all CpGs analysed. In the teratozoospermia group, 11 of 19 patients presented a loss of methylation at variable CpG positions either in the IGF2 DMR2 or in both the IGF2 DMR2 and the 6th CTCF of the H19 DMR. In the OAT group, 16 of 22 patients presented a severe loss of methylation of the 6th CTCF, closely correlated with sperm concentration. The methylation state of DMR0 and of the 3rd CTCF was never affected by the pathological status of sperm samples. This study demonstrates that epigenetic perturbations of the 6th CTCF site of the H19 DMR might be a relevant biomarker for quantitative defects of spermatogenesis in humans. Moreover, we defined a methylation threshold sustaining the classification of patients in two groups, unmethylated and methylated. Using this new classification of patients, the observed intrinsic imprinting defects of spermatozoa appear not to impair significantly the outcome of assisted reproductive technologies.

Semen quality and male reproductive health: the controversy about human sperm concentration decline

Concern about the effect of environmental changes on male reproductive health has grown in recent years to become a major preoccupation in some developed countries. A possible decline in human sperm concentration was suggested in the early seventies following studies in the US. In 1992 a metaanalysis of 61 articles published by Carlsen et al. concluded that the mean sperm count of healthy men had declined by 1% per year over the previous 50 years. From 1995 and onwards, some retrospective, longitudinal analyses of the sperm count of fertile or infertile men contradicted this while others did not. The demonstration of a geographical variation in sperm concentration, between and within countries or regions, appears to be less controversial. The amplitude of the difference observed cannot only be explained by methodological or confounding factors, and must to some extent be attributed to ethnic, genetic or environmental factors. As many of the published studies suffer from imprecision regarding the description of population characteristics and confounding factors, and were not designed with controlled and standardised methodology, the debate remains open. Prospective studies in well‐defined cohorts of men in various populations are required to evaluate the potential effect of external factors on male reproductive health. These studies should not be limited to the analysis of sperm concentration, as this may not be the best biomarker of testis function and human fertility.

Influence of sickle cell disease and treatment with hydroxyurea on sperm parameters and fertility of human males

The use of hydroxyurea has considerably modified the prognosis of sickle cell disease and many more patients now reach reproductive age. This study shows alterations of semen parameters due to sickle cell disease that seem to be exacerbated by hydroxyurea treatment. The authors suggest that a pre-treatment sperm analysis be performed and sperm cryopreservation be offered to patients before hydroxyurea treatment. Background Recent progress in the treatment of sickle cell disease, in particular the use of hydroxyurea, has considerably modified the prognosis of this disease. Many more patients now reach reproductive age. The objective of this study was to assess the potential impact of hydroxyurea on the semen of patients. Design and Methods In this retrospective multicenter study, we evaluated the sperm parameters and fertility of 44 patients and analyzed the potential impact of hydroxyurea. Results We report data from the largest series so far of semen analyses in patients with sickle cell disease: 108 samples were analyzed, of which 76 were collected before treatment. We found that at least one sperm parameter was abnormal in 91% of the patients before treatment, in agreement with published literature. All sperm parameters seemed to be affected in semen samples collected during hydroxyurea treatment, and this impairment occurred in less than 6 months, later reaching a plateau. Furthermore, after hydroxyurea cessation, while global results in 30 patients were not statistically different before and after hydroxyurea treatment, in four individuals follow-up sperm parameters did not seem to recover quickly and the total number of spermatozoa per ejaculate fell below the normal range in about half the cases. Conclusions The observed alterations of semen parameters due to sickle cell disease seem to be exacerbated by hydroxyurea treatment. Until prospective studies reveal reassuring findings, we suggest that a pre-treatment sperm analysis be performed and sperm cryopreservation be offered to patients before hydroxyurea treatment.

Hepatitis C virus in the semen of men coinfected with HIV-1: prevalence and origin.

Objective:To compare the prevalence of hepatitis C (HCV) RNA in semen from men infected with HCV and those coinfected with HIV-1/HCV and to study the origin of HCV shed in semen. Design:Two prospective studies (HC EP09 and BINECO) included 120 HCV-positive men, 82 coinfected with HIV-1; all had positive HCV RNA detection in blood. Methods:Paired blood and semen samples were collected for HCV RNA detection and quantification in seminal plasma and in blood serum; repeated semen samples were obtained for 45 men. HCV RNA was sought in spermatozoa and non-sperm cells. Phylogenetic analysis of the HVR-1 region of HCV compared the quasispecies in blood serum and seminal plasma of two men. Results:HCV RNA was more frequently found in the semen of men coinfected with HIV-1 (37.8%) than in those with only HCV infection (18.4%) (P = 0.033). HCV RNA detection in semen was intermittent and was positive in at least one semen sample of 42.8% of HIV-1/HCV-coinfected men who provided repeated samples. Men with HCV-positive semen had significantly higher HCV load in blood than men with HCV-negative semen (P = 0.038). Phylogenetic comparison of HCV quasispecies in blood and in semen showed no evidence of HCV replication in genital leukocytes; however, a phenetic structure was observed between compartments (P < 0.001). Conclusions:HCV particles in semen originate from passive passage from blood, with preferential transfer of some variants. Nearly half of HIV-1/HCV-coinfected men may intermittently harbour HCV in their semen. Recommendations of protected sex for HIV-infected individuals should be reinforced.

In vitro follicular growth affects oocyte imprinting establishment in mice

In vitro folliculogenesis of cryopreserved ovarian tissue could be an effective method for insuring fertility for patients who receive gonadotoxic treatment. Although several culture systems have been described for growing female gametes in vitro, the production of competent oocytes for further development remains a considerable challenge. The purpose of our study was to determine whether maternal primary imprinting progresses normally during mouse oocyte growth in vitro. We analysed the DNA methylation status of differentially methylated regions of the imprinted genes H19, Mest/Peg1 and Igf2R using fully grown germinal vesicle-stage oocytes (fg oocytes) produced by in vitro folliculogenesis from early preantral follicles. When compared to fg oocytes removal from control females, we observed after in vitro development, a loss of methylation at the Igf2R locus in six out of seven independent experiments and Mest/Peg1 locus (one out of seven), and a gain of methylation at the H19 locus (one out of seven). These results provide insight into the dysregulation of the process of primary imprinting during oocyte growth in vitro and highlight the need for effective new biomarkers to identify complete nuclear reprogramming competence after in vitro folliculogenesis.

The acrosome reaction in human spermatozoa

During gamete interaction, sperm acrosome reaction (AR) induced by oocyte investment is a prerequisite event for the spermatozoa to pass through the zona pellucida (ZP), fuse with and penetrate the oocyte. Progesterone (P4), secreted by cumulus cells, is an important cofactor for the occurrence of this exocytosis event. The AR results from the fusion between outer acrosomal and plasma membranes, leading to inner acrosomal membrane exposure. Binding of agonists, P4 or ZP3 glycoprotein, to plasma membrane sperm receptors activates intraspermatic signals and enzymatic pathways involved in the AR. Among the proteins or glycoproteins described as potential sperm receptors for ZP, Gi/Go protein‐coupled and tyrosine kinase receptors have been described. Sperm receptors for P4 are poorly characterized, except a putative GABAA‐like receptor. ZP‐ and P4‐promoted AR is mediated by an obligatory intracellular calcium increase, appearing first at the acrosome equatorial segment and spreading throughout the head. The plasma membrane channels involved in calcium entry are operated by a plasma membrane depolarization and protein phosphorylations mediated by protein kinase C and tyrosine kinase protein. Part of the calcium increase could also be due to intracellular store release through IP3‐ and nucleotide (cAMP)‐gated channels. Besides adenylate cyclase and phospholipase C activations, intracellular calcium increase also stimulates PLA2 activity and actin depolymerization, leading to membrane fusion. Evaluation of AR by staining or fluorescent probes can be useful to predict fertilization success and to direct the therapeutic strategy in male infertility.

Decrease in HIV-1 seminal shedding in men receiving highly active antiretroviral therapy: an 18 month longitudinal study (ANRS EP012)

Thirty-nine HIV-1-infected men were prospectively tested for HIV seminal shedding after the initiation of highly active antiretroviral therapy. HIV RNA drastically decreased in the semen of all men, but low levels remained detectable in three men at month 18. Proviral HIV DNA became undetectable in the seminal cells of all men after 18 months. HIV-infected cells in the male genital compartment may come from the intermittent passage of blood lymphocytes, rather than constituing a major local reservoir.

Modulation of imprinted gene network in placenta results in normal development of in vitro manipulated mouse embryos

Genomic imprinting regulates the expression of a group of genes monoallelically expressed in a parent-of-origin specific manner. Allele-specific DNA methylation occurs at differentially methylated regions (DMRs) of these genes. We have previously shown that in vitro fertilization and embryo culture result in methylation defects at the imprinted H19-Igf2 locus at the blastocyst stage. The current study was designed to evaluate the consequences of these manipulations on genomic imprinting after implantation in the mouse. Blastocysts were produced following three experimental conditions: (i) embryos maintained in culture medium after in vivo fertilization or (ii) in vitro fertilization and (iii) a control group with embryos obtained after in vivo fertilization and timed mating. Blastocysts were all transplanted into pseudopregnant females. Embryos and placentas were collected on day 10.5 of development. DNA methylation patterns of the H19, Igf2, Igf2r and Dlk1-Dio3 DMRs were analyzed by quantitative pyrosequencing. In contrast to blastocyst stage, methylation profiles were normal both in embryonic and placental tissues after in vitro fertilization and culture. Expression of a selected set of imprinting genes from the recently described imprinted gene network (IGN) (including Igf2 and H19) was analyzed in placental tissues by quantitative RT-PCR. Placentas obtained after in vitro fertilization and embryo culture displayed significantly disturbed levels of H19 and Igf2 mRNA, as well as of most other genes from the IGN. As embryos were phenotypically normal, we hypothesize that the modulation of a coordinated network of imprinted genes results in a compensatory process capable of correcting potential dysfunction of placenta.

Assisted reproduction in Hiv-1-serodifferent couples: the need for viral validation of processed semen

Background: Many HIV-infected men and women have a strong desire for a child. Assisted reproductive technologies (ART) are an option for HIV-serodifferent couples to reduce the risk of HIV transmission from an infected man to the woman. Potential HIV contamination of selected spermatozoa after semen processing is an important issue in this context. Methods: HIV in processed semen obtained in our laboratory since 1995 were analysed. HIV RNA and DNA detection was performed in the selected spermatozoa of 125 men. HIV RNA was analysed in blood and semen plasma as well as HIV DNA in non-sperm cells. Results: HIV RNA and DNA were detected in the selected spermatozoa of eight and two men (6.4% and 1.6%), respectively. HIV RNA was detected with a median load of 5 copies/106 spermatozoa. Six of the eight men were untreated, one was taking nucleoside analogue therapy and one was on highly active antiretroviral treatment (HAART). HIV RNA detection was more likely to be positive in selected spermatozoa of men with high seminal plasma viral load. HIV RNA was detected in 26% and 11% of selected spermatozoa fractions when the seminal plasma load was > 10 000 copies/ml and 20–10 000 copies/ml, respectively, but in none when the seminal plasma tested negative. Conclusion: Selected spermatozoa may be positive for HIV RNA detection even in treated patients. Viral validation of processed semen is necessary in ART programmes for serodifferent couples, particularly in men with only partially or poorly controlled HIV infection.