Biomedical subjects

P May-Panloup

Publications and source records attributed to P May-Panloup.

6 recordsLinked to original sources

PubMed2006

[Spermatozoon mitochondrial DNA].

Mitochondria play a primary role in cellular energetic metabolism, homeostasis and death. In spermatozoa, in particular, mitochondria produce the ATP necessary for motility. Mitochondrial functions depend, at least partially, on mitochondrial DNA (mtDNA). The mitochondrial genome, the transmission of which is exclusively maternal contributes to cytoplasmic heredity. Qualitative and quantitative mtDNA abnormalities have been associated with male infertility. This review focuses on the role of mtDNA in human fertility.

DNA, Mitochondrial↗

PubMed2004

Low oocyte mitochondrial DNA content in ovarian insufficiency.

BACKGROUND: Mitochondrial biogenesis and bioenergetics play an important role in oocyte maturation and embryo development. We have investigated the relationship between defective mitochondrial biogenesis and the lack of oocyte maturity observed during IVF procedures with patients suffering from ovarian dystrophy and ovarian insufficiency. METHODS: We used real-time quantitative PCR to quantify mitochondrial DNA (mtDNA) in 116 oocytes obtained from 47 women undergoing the ICSI procedure. We compared the mtDNA content of oocytes from women with a normal ovarian profile with that of oocytes from women with ovarian dystrophy and ovarian insufficiency. RESULTS: We found an average of 256,000 +/- 213,000 mitochondrial genomes per cell. The mean mtDNA copy number was not significantly different in ovarian dystrophy compared with controls, but it was significantly lower in oocytes from women with ovarian insufficiency (100,000 +/- 99,000, P < 0.0001). CONCLUSIONS: Our results suggest that low mtDNA content is associated with the impaired oocyte quality observed in ovarian insufficiency.

Case-Control Studies↗

PubMed2004

In vitro embryo production efficiency in cattle and its association with oocyte adenosine triphosphate content, quantity of mitochondrial DNA, and mitochondrial DNA haplogroup.

Mitochondria have a broad range of functions that affect reproduction, and structural as well as quantitative variation in mtDNA has been associated with gamete quality and reproductive success. To investigate the mitochondria effect on in vitro embryo production, we collected oocytes by ultrasound-guided follicular aspiration from donor cows known to differ in the developmental capacity, measured by the blastocyst formation rate, of their oocytes. To evaluate the potential effects of mtDNA and mitochondrial function on oocyte quality, the donor cows' mtDNA control region was sequenced and, after pairwise comparisons of polymorphisms, animals were grouped into two major haplogroups. The number of mtDNA molecules per oocyte was quantified by real-time PCR, and the adenosine triphosphate (ATP) content was measured in each oocyte to identify variations between haplogroups. Overall, ATP stocks in oocytes of the two haplogroups differed significantly (P < 0.05; means +/- SEM) both at the germinal vesicle and metaphase II stages (2.8 +/- 0.06 pmol vs. 2.6 +/- 0.07 pmol and 2.9 +/- 0.1 pmol vs. 2.3 +/- 0.06 pmol, respectively). The proportion of development to blastocyst was significantly different between haplogroups (22.3 +/- 2.1 % vs. 36.7 +/- 2.9 %). The number of mtDNA molecules per oocyte was highly variable (377 327 +/- 14 104, ranging from 2.0 x 10(3) to 1.2 x 10(6)) but not significantly different between the two haplogroups; significant differences were observed between animals without any apparent relationship to blastocyst production. These data suggest that mitochondria and mtDNA haplogroup affect the developmental capacity of bovine oocytes in vitro.

Adenosine Triphosphate↗

PubMed2003

Increased sperm mitochondrial DNA content in male infertility.

BACKGROUND: There is increasing evidence that mitochondrial DNA (mtDNA) anomalies in sperm may lead to infertility. Point mutations, deletions and the presence of a specific mtDNA haplogroup have been associated with poor sperm quality, but little attention has been paid to the role of mtDNA content. METHODS: Using density gradient separation and swim-up methods, we selected motile sperm from 32 normal and 35 abnormal sperm samples. The mtDNA/beta-globin gene ratio was determined by real-time quantitative PCR. RESULTS: The average mtDNA/beta-globin ratio of sperm collected from 100% density layers was 1.4 for normal sperm, 6.1 for sperm samples presenting at least one abnormal criterion [among the three criteria established by World Health Organization (1999), i.e. sperm count, motility and morphology], and 9.1 for sperm samples presenting two or more of these abnormal criteria. These differences are very highly significant (P < 0.0001). The mtDNA numbers were also much greater in sperm collected from the 40% density gradient layers (mean: 17.1, P < 0.001), known to contain the most abnormal sperm of the sperm samples, than in those collected from the 100% layers known to contain sperm with the best fertilizing ability. CONCLUSION: Our results showed significant mtDNA amplification in sperm collected from abnormal sperm samples.

Computer Systems↗

PubMed2001

[Genetic male infertility and medically assisted reproduction].

About half the cases of infertility have their origin in the male partner. Infertility due to males has several possible aetiologies. In about 30% of cases, genetic disorders are suspected of being the main cause. They could interfere with the development of the male gonads, the urogenital tract or the hypothalamo-hypophyseal axes. Such disorders could also stop germ cell generation and maturation or lead to the production of non-functional spermatozoa. Genetic disorders of chromosomal origin could give rise to abnormal karyotypes or germinal mosic figure. They could involve gene abnormalities affecting numerous genes localized on several chromosomes, in particular the Y chromosome. The physiopathologic identification of male infertility is interesting because of the risk of the genetic factors involved being transmitted to the offspring. The subject is of importance, specially because of the increasing use of intracytoplasmic sperm injections. Couples should therefore be precisely counselled to enable them to make a well-informed choice among various solutions, e.g. ART, with or without sperm donation, or adoption.

Chromosome Aberrations↗

PubMed2001

Mitochondrial DNA content affects the fertilizability of human oocytes.

Mitochondrial DNA content varies considerably in oocytes, even when collected from the same patient. In the present study, real-time quantitative polymerase chain reaction analysis of 113 unfertilized oocytes obtained from 43 patients revealed an average of 193,000 (range: 20,000 to 598,000) mitochondrial genomes per cell. We compared several groups of oocytes to investigate the relationship between mitochondrial DNA content and fertilizability. The average mitochondrial DNA copy number was significantly lower in cohorts suffering from fertilization failure compared to cohorts with a normal rate of fertilization. In addition, the mitochondrial copy number of oocytes from patients with fertilization failure due to unknown causes was significantly lower than that of oocytes from patients in which IVF failure was due mainly to a severe sperm defect. The lower mtDNA copy number could be due to defective cytoplasmic maturation of oocytes. We conclude that low mitochondrial DNA content, due to inadequate mitochondrial biogenesis or cytoplasmic maturation, may adversely affect oocyte fertilizability.

Adult↗