186,408 research outputs found
Microanatomy of the epididymis and vas deferens
No full textIn this review, the structural and functional characteristics of the human epididymis, including vas efferens and ductus deferens, are revisited under the morphological and ultrastructural point of view New surface sperm antigens, enabling the fertilizing power during the epididymal transit, various epididymal microenvironments and their activities on the spermatozoa are reported. This revision is important because the recent procedures of assisted reproduction, aimed at overcoming the cases of obstructive azoospermia, use the spermatozoa aspirated from the proximal segments of the epididymis and suggest a flexibility of the epididymal function with regard to the fertilizing sperm capacity. In my opinion these proce dures must be based on an accurate investigation on the function of the different epididymal districts. Moreover, in patients affected by congenital absence of the vas deferens (CAV), the ultrastructural examination of the spermatozoa aspirated from the proximal segments of the epididymis revealed that most of them are defective: in fact the absence of the vas deferens seems to affect the development and the functional properties of the epididymal spermatozoa
Submicroscopical mathe-matical evaluation of spermatozoa in assisted reproduction. 3. Partial zona dissection (PZD). (Notulae seminologicae 12)
No full textThis paper belongs to a series of application of the Baccetti's et al. (1995) formula to the submicroscopical mathematical examination of the human spermatozoa used for assisted reproduction. The present experiment concerns partial zona dissection, a technique requiring a careful evaluation of sperm quality in order to predict the success of the program. Our results demonstrate that the sperm submicroscopic characters introduced in the formula are clearly correlated with the result of PZD. In fact the two numbers concerning the sperm ultrastructural quality (percentage and total number of spermatozoa free from defects in the ejaculate) obtained in successful and unsuccessful PZD groups, showed a large difference (P < 0.01). The most important characteristics seem to be the quality of the acrosomal complex, the condition of the chromatin and the mitochondrial assembly. All these characteristics are expressed with largely different means in successful and unsuccessful ejaculates (from P < 0.05 to P < 0.01). A comparison with the results previously obtained in ICSI (Strehler et al., 1995) and IVF (Piomboni et al., 1996) shows that sperm quality is significantly more implicated in the success of IVF than of PZD or ICSI
Chromosomal Aberrations and aneuploidies of Spermatozoa
No full textChromosomal abnormalities are relevant causes of human infertility, affecting 2 -14 % of infertile males. Patients with seminal anomalies could be affected by improper meiotic recombination and increased sperm chromosome aneuploidy. Since the transmission of a haploid chromosomal asset is fundamental for embryo vitality and development, the study of sperm chromosomes has become fundamental because intracytoplasmic sperm injection allows fertilization in cases of severe male infertility. In this chapter we summarize the data on the incidence of sperm aneuploidy, detected by fluorescence in situ hybridization (FISH), in infertile men with normal or abnormal karyotype. The possibility of reducing sperm chromosomal imbalance is also reported. Among control males, the lowest aneuploidy rate was detected (range: 0.09 -0.14 % for autosomes; 0.04 -0.10 % for gonosomes). In infertile patients with normal karyotype, the severity of semen alteration is correlated with the frequency of aneuploidy, particularly for X and Y chromosomes. Among patients with abnormal karyotype, 47,XXY and 47,XYY carriers showed a high variability of sperm aneuploidy both for gonosomes and autosomes. In Robertsonian translocation carriers, the increase in aneuploidy rate was particularly evident for total sex disomy, and resulted mainly from interchromosomal effect (ICE). In reciprocal translocation carriers, a high percentage of unbalanced sperm (approximately 50 %) was detected, perhaps mostly related to ICE. Sperm chromosomal constitution could be analyzed to obtain more accurate information about the causes of male infertility. It would be worthwhile to evaluate the benefits of a therapy with recombinant Follicle Stimulating Hormone (rFSH) on sperm chromosome segregation in selected infertile males. © 2014 Springer Science+Business Media New York
Taste receptor polymorphisms and male infertility
No full textSTUDY QUESTION: Are polymorphisms of taste receptor genes associated with male infertility?
SUMMARY ANSWER: This study has showed the associations between three single nucleotide polymorphisms (SNPs) in taste receptors genes (TASR) and male infertility.
WHAT IS KNOWN ALREADY: Recent studies showed the expression of taste receptors in the testis and in spermatozoa, suggesting their possible role in infertility. The vast genetic variability in taste genes results in a large degree of diversity in various human phenotypes.
STUDY DESIGN, SIZE, DURATION: In this study, we genotyped 19 SNPs in 12 taste related genes in a total of 494 Caucasian male patients undergoing semen evaluation at the Centre of Couple Sterility of the Siena University Hospital. Consecutive patients were enrolled during infertility investigations from October 2014 to February 2016.
PARTICIPANTS/ MATERIALS, SETTING, METHODS: Median age of the patients was 36 years (18-58) and 141 were smokers. Genotyping was performed using the allele-specific PCR. The statistical analysis was carried out using generalized linear model (GLM) to explore the association between age, smoking, the genetic polymorphisms and sperm parameters.
MAIN RESULTS AND THE ROLE OF CHANCE: We observed that the homozygous carriers of the (G) allele of the TAS2R14rs3741843 polymorphism showed a decreased sperm progressive motility compared to heterozygotes and (A) homozygotes (P = 0.003). Moreover, the homozygous carriers of the (T) allele of the TAS2R3-rs11763979 SNP showed fewer normal acrosome compared with the heterozygous and the homozygous carriers of the (G) allele (P = 0.002). Multiple comparisons correction was applied and the Bonferronicorrected critical P-value was = 0.003.
LIMITATIONS, REASONS FOR CAUTION: The analysis is restricted to SNPs within genes and to men of Caucasian ancestry.
WIDER IMPLICATIONS OF THE FINDINGS: In silico analyses strongly point towards a functional effect of the two SNPs: TAS2R14rs3741843 regulates TAS2R43 expression, a gene that is involved in cilia motility and therefore could influences sperm mobility; the (T) allele of TAS2R3-rs11763979 increases the expression of the WEE2 antisense RNA one gene (WEE2-AS1). According to Genotype-Tissue Expression (GTEx) project the WEE2 gene is expressed in the testes where presumably it has the role of down regulating meiotic cell division. It is plausible to hypothesize that the WEE2-AS1 increased expression may down regulate WEE2 which in turn can alter the natural timing of sperm maturation increasing the number of abnormal sperm cells
The role of mitochondria in energy production for human sperm motility
No full textMitochondria of spermatozoa are different from the corresponding organelles of somatic cells, in both their morphology and biochemistry. The biochemical differences are essentially related to the existence of specific enzyme isoforms, which are characterized by peculiar kinetic and regulatory properties. As mitochondrial energy metabolism is a key factor supporting several sperm functions, these organelles host critical metabolic pathways during germ cell development and fertilization. Furthermore, spermatozoa can use different substrates, and therefore activate different metabolic pathways, depending on the available substrates and the physico-chemical conditions in which they operate. This versatility is critical to ensure fertilization success. However, the most valuable aspect of mitochondria function in all types of cells is the production of chemical energy in the form of ATP which can be used, in the case of spermatozoa, for sustaining sperm motility. The latter, on the other hand, represents one of the major determinants of male fertility. Accordingly, the presence of structural and functional alterations in mitochondria from asthenozoospermic subjects confirms the important role played by these organelles in energy maintenance of sperm motility. The present study gives an overview of the current knowledge on the energy-producing metabolic pathways operating inside human sperm mitochondria and critically analyse the differences with respect to somatic mitochondria. Such a comparison has also been carried out between the functional characteristics of human sperm mitochondria and those of other mammalian species. A deeper understanding of mitochondrial energy metabolism could open up new avenues of investigation in bioenergetics of human sperm mitochondria, both in physiological and pathological condition
The role of mitochondria in energy production for human sperm motility
No full textMitochondria of spermatozoa are different from the corresponding organelles of somatic cells, in both their morphology and biochemistry. The biochemical differences are essentially related to the existence of specific enzyme isoforms, which are characterized by peculiar kinetic and regulatory properties. As mitochondrial energy metabolism is a key factor supporting several sperm functions, these organelles host critical metabolic pathways during germ cell development and fertilization. Furthermore, spermatozoa can use different substrates, and therefore activate different metabolic pathways, depending on the available substrates and the physico-chemical conditions in which they operate. This versatility is critical to ensure fertilization success. However, the most valuable aspect of mitochondria function in all types of cells is the production of chemical energy in the form of ATP which can be used, in the case of spermatozoa, for sustaining sperm motility. The latter, on the other hand, represents one of the major determinants of male fertility. Accordingly, the presence of structural and functional alterations in mitochondria from asthenozoospermic subjects confirms the important role played by these organelles in energy maintenance of sperm motility. The present study gives an overview of the current knowledge on the energy-producing metabolic pathways operating inside human sperm mitochondria and critically analyse the differences with respect to somatic mitochondria. Such a comparison has also been carried out between the functional characteristics of human sperm mitochondria and those of other mammalian species. A deeper understanding of mitochondrial energy metabolism could open up new avenues of investigation in bioenergetics of human sperm mitochondria, both in physiological and pathological conditions
Embryo development pregnancy and twin delivery after microinjection of 'stump' spermatozoa
No full textIntracytoplasmic sperm injection was performed with immotile spermatozoa affected by tail 'stump' defect, and resulted in normal fertilization, embryo transfer and pregnancy in a 35-year-old female. The husband had a consanguineous ancestry. Two healthy babies, a male and a female, were born and this confirms that male infertility due to certain genetic sperm defects can be overcome by the intracytoplasmic sperm injection-assisted reproduction technique. The likely genetic origin of this sperm defect and the probability of the male offspring inheriting this sperm defect should be considered. The fertilization ability of stump spermatozoa, microinjected into the oocyte, is explained on the basis of experience from our previous research
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