Paola Piomboni

Cellular and molecular aspects of ovarian follicle ageing

It is well established that age-related decline of the biological capacity of a woman to reproduce is primarily related to the poor developmental potential of her gametes. This renders female ageing the most significant determinant of success in IVF. Starting with a reference picture of the main molecular and cellular failures of aged oocytes, granulosa cells and follicular microenvironment, this review focuses on age-related biochemical mechanisms underlying these changes. According to the most relevant concept of ageing, age-associated malfuction results from physiological accumulation of irreparable damage to biomolecules as an unavoidable side effect of normal metabolism. More than a decade after the free radical theory of ovarian ageing, biological and clinical research supporting the involvement of oxidative injuries in follicle ageing is discussed. Looking for the aetiology of oxidative stress, we consider the effect of ageing on ovarian and follicular vascularization. Then, we propose a potential role of advanced glycation end-products known to be involved in the physiological ageing of most tissues and organs. We conclude that future investigation of age-related molecular damage in the different ovarian components will be imperative in order to evaluate the possibility to save or rescue the developmental potential of aged oocytes.

The role of mitochondria in energy production for human sperm motility.

Mitochondria 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.

Spermatogenesis in a man with complete deletion of USP9Y.

Deletions in the azoospermia factor region AZFa on the human Y chromosome and, more specifically, in the region that encompasses the ubiquitin-specific peptidase 9, Y-linked gene USP9Y have been implicated in infertility associated with oligospermia and azoospermia. We have characterized in detail a deletion in AZFa that results in an absence of USP9Y in a normospermic man and his brother and father. The association of this large deletion with normal fertility shows that USP9Y, hitherto considered a candidate gene for infertility and azoospermia, does not have a key role in male reproduction. These results suggest that it may not be necessary to consider USP9Y when screening the Y chromosome of infertile or subfertile men for microdeletions.

The debate on the presence of HIV-1 in human gametes

The debate about the presence of HIV-1 particles in human gametes and recent experimental results are reported in detail. Using immunocytochemistry, in situ hybridization at electron microscopy level, polymerase chain reaction and in vitro fertilization, it has been demonstrated that human spermatozoa can incorporate HIV-1 using special receptors, different from the usual CD4, and that they remain active and able to vehicle the viral particles into the oocyte, which is regularly fertilized. Moreover, by transmission electron microscopy (TEM), immunocytochemistry and PCR, we demonstrated that cell-free HIV-1 is not able to bind and penetrate the human oocyte in vitro. We attribute this behaviour to the fact that the oocyte and cumulus cells are devoid both of GalAAG and of CD4 receptors. PCR analysis indicated that mRNAs specific for CD4, CXCR4 and CCR5 proteins were absent, too.

Phenotypic variation within European carriers of the Y-chromosomal gr/gr deletion is independent of Y-chromosomal background

Background: Previous studies have compared sperm phenotypes between men with partial deletions within the AZFc region of the Y chromosome and non-carriers, with variable results. In this study, a separate question was investigated, the basis of the variation in sperm phenotype within gr/gr deletion carriers, which ranges from normozoospermia to azoospermia. Differences in the genes removed by independent gr/gr deletions, the occurrence of subsequent duplications or the presence of linked modifying variants elsewhere on the chromosome have been suggested as possible causal factors. This study set out to test these possibilities in a large sample of gr/gr deletion carriers with known phenotypes spanning the complete range. Results: In total, 169 men diagnosed with gr/gr deletions from six centres in Europe and one in Australia were studied. The DAZ and CDY1 copies retained, the presence or absence of duplications and the Y-chromosomal haplogroup were characterised. Although the study had good power to detect factors that accounted for ⩾5.5% of the variation in sperm concentration, no such factor was found. A negative effect of gr/gr deletions followed by b2/b4 duplication was found within the normospermic group, which remains to be further explored in a larger study population. Finally, significant geographical differences in the frequency of different subtypes of gr/gr deletions were found, which may have relevance for the interpretation of case control studies dealing with admixed populations. Conclusions: The phenotypic variation of gr/gr carriers in men of European origin is largely independent of the Y-chromosomal background.

Quantitative evaluation of spermatozoa ultrastructure after acupuncture treatment for idiopathic male infertility

Objective To evaluate the ultramorphologic sperm features of idiopathic infertile men after acupuncture therapy. Design Prospective controlled study. Setting Christian-Lauritzen-Institut, Ulm, IVF center Munich, Germany, and Department of General Biology, University of Siena, Siena, Italy. Patient(s) Forty men with idiopathic oligospermia, asthenospermia, or teratozoospermia. Intervention(s) Twenty eight of the patients received acupuncture twice a week over a period of 5 weeks. The samples from the treatment group were randomized with semen samples from the 12 men in the untreated control group. Main Outcome Measure(s) Quantitative analysis by transmission electron microscopy (TEM) was used to evaluate the samples, using the mathematical formula based on submicroscopic characteristics. Result(s) Statistical evaluation of the TEM data showed a statistically significant increase after acupuncture in the percentage and number of sperm without ultrastructural defects in the total ejaculates. A statistically significant improvement was detected in acrosome position and shape, nuclear shape, axonemal pattern and shape, and accessory fibers of sperm organelles. However, specific sperm pathologies in the form of apoptosis, immaturity, and necrosis showed no statistically significant changes between the control and treatment groups before and after treatment. Conclusion(s) The treatment of idiopathic male infertility could benefit from employing acupuncture. A general improvement of sperm quality, specifically in the ultrastructural integrity of spermatozoa, was seen after acupuncture, although we did not identify specific sperm pathologies that could be particularly sensitive to this therapy.

Notulae seminologicae. 2. The "short tail" and "stump" defect in human spermatozoa.

Summary. In this note several cases of stunted tails involving the total sperm population in sterile humans are described. Half of the cases are classified as ‘short tailed’ spermatozoa, the other half as ‘stump defect’ previously described in bulls. Both defects are referred in details at electron microscopical level.

Recent advances in human sperm pathology

Electron microscopy is a valuable tool in understanding not only the presence but also the nature of sperm malformation causing human infertility. In the past, we have examined patients affected by severe teratospermia concomitant with andrological pathologies such as varicocele, cryptorchidism, and infection. In particular, we have demonstrated that, in the case of varicocele, a combination of different phenotypic defects typical of immature spermatozoa is present. This general study was carried out on 2000 infertile men who presented for sperm analysis at our laboratory over the course of 10 years. The ejaculate of all of them was examined by electron microscopy, statistically evaluated by a formula created by us (J of Andrology, 1995), and cytogenetically checked by fluorescence microscopy techniques. First of all, this study concerned the techniques of assisted reproduction, i.e. intracytoplasmic sperm injection (ICSI), partial zona disruption (PZD), and in vitro fertilization (IVF). The conclusion was that the evaluation of the sperm quality of males attempting artificial insemination must concern not only motility or staining characteristics but mainly submicroscopical and molecular properties. Moreover, the effect of follicle stimulating hormone (FSH) treatment on human sperm quality has been evaluated by our group testing the ultrastructure and the function of spermatozoa before and after the therapy. Using the sperm as an andrological monitor, it seems that the therapeutic effect of FSH depends on the type of sperm affections. In particular, phenotypic defects as apoptosis and immaturity can be corrected by FSH treatment. More recently, we approached the problem of genotypic sperm infertility. We demonstrated that some very peculiar defects, detected by electron microscopy, show a hereditary transmission having a genetic basis. In fact, they are much more frequent in consanguineous patients, and are clearly related to different degrees of consanguinity. Frequently, chromosomal translocations have sometimes been found correlated to these defects.A consequence of these demonstrations is that most of the present sperm defects are phenotypic and can be submitted to surgical or pharmaceutical cares, but others have genetic origin and cannot be corrected by surgical or pharmaceutical treatment. These malformations are transmitted to the offspring by techniques of assisted fertilization.

New insights into the interaction between the gp120 and the HIV receptor in human sperm (human.sperm/gp120/galactoglycerolipid/antigalactosylceramide/seminolipid/spermatogonia)

Abstract The human immunodeficiency virus (HIV) can infect some cell types which lack CD4. Galactosylceramide, a glycolipid present in the nervous system and colonic epithelial cells, has been implicated in the virus entry in these cells. Our data demonstrate that the HIV surface glycoprotein gp120 binds to the galactosyl-alkyl-acylglycerol (GalAAG), a glycolipid structurally related to galactosylceramide present on the surface membrane of the spermatozoa. In this paper, we review our previous data and further confirm the specificity of the interaction between this galactoglycerolipid and the gp120. Consistent with the structural similarity to galactosylceramide, the sperm GalAAG is capable of specifically binding the gp120. The specificity of the binding of antibodies anti-galactosylceramide and the gp120 to the sperm extract and to the purified GalAAG fraction prepared from the same extract has been demonstrated utilizing an ELISA assay which favors sensitivity and specificity. Immunofluorescence and immunoelectron microscopy data show a different localization for the GalAAG and its sulfated form the seminolipid (SGalAAG). The GalAAG is preferentially localized in the equatorial segment and the middle piece of the sperm tail, while the seminolipid is widely distributed on the membrane of the spermatozoa. These data indicate that human sperm express on their surface membrane a glycolipid similar in structure to galactosylceramide, the receptor for HIV identified in the CD4 − cells, that could function as a HIV receptor and possibly be implicated in its transmission.

Localisation of two classes of acetylcholine receptor-like molecules in sperms of different animal species

The distribution of different classes of acetylcholine (ACh) receptor-like molecules in sperms of different invertebrate and vertebrate species is described. ACh receptor molecules belong to one of two classes: muscarinic receptors (mAChRs), associated with signal transduction mechanisms in the inner domain of the cell, and nicotinic receptors (nAChRs), capable of opening Na+ channels when activated by the ligand. Molecules immunologically related to mAChRs and to ACh can be identified by specific antibodies, and revealed by immunofluorescent or immunogold staining; the nicotinic receptor-like molecules are localised as curare-sensitive affinity sites for alpha-bungarotoxin. In all species studied, both classes of receptors were found, with a similar distribution. Muscarinic-like molecules were found mainly in the sperm head regions of most species; such a localisation may be correlated to a function in sperm-egg interaction, for instance in the regulation of the block to polyspermy. Nicotinic-like molecules are present mainly in the tail and in the post-acrosomal region of most animals, thus confirming their function in the regulation of sperm propulsion, but are also present at the acrosomal region of most species. The distribution patterns of the different classes of molecules indicate that both may be involved in sperm-egg interactions, in addition to their known function in the regulation of sperm propulsion.