Massimo Menegazzo

High-power microscopy for selecting spermatozoa for ICSI by physiological status

Sperm selection for intracytoplasmic sperm injection (ICSI), based on standard morphology, can fail to select normal cells, and actual methods to evaluate their physiological status do not allow their later use for ICSI. Some authors have demonstrated that sperm selection based on high-magnification morphology is associated with a better ICSI outcome, above all in subjects with severe testicular failure. In this study there was an evaluation of mitochondrial function, chromatin structure and sperm aneuploidies on whole sperm samples from 30 subjects: 10 normozoospermic controls and 20 patients that were severely oligozoospermic due to testicular damage or partial obstruction of the seminal ducts. All severely oligozoospermic patients showed worse mitochondrial function and chromatin status, while sperm aneuploidies were significantly increased only in those subjects with severe testicular damage (P < 0.001). In the latter patients the analysis of a single spermatozoon, performed after morphological selection by high-magnification microscopy, showed significantly better mitochondrial function, chromatin status and aneuploidy rate than observed in unselected cells (all P < 0.001). Interestingly, these parameters were further improved when nuclear vacuoles were lacking. These results suggest a strong relationship between high-magnification morphology and the status of spermatozoa, and they may explain the better results of ICSI obtained using spermatozoa selected by high-magnification microscopy.

Mechanism of Human Papillomavirus Binding to Human Spermatozoa and Fertilizing Ability of Infected Spermatozoa

Human papillomaviruses (HPVs) are agents of the most common sexually transmitted diseases in females and males. Precise data about the presence, mechanism of infection and clinical significance of HPV in the male reproductive tract and especially in sperm are not available. Here we show that HPV can infect human sperm, it localizes at the equatorial region of sperm head through interaction between the HPV capsid protein L1 and syndecan-1. Sperm transfected with HPV E6/E7 genes and sperm exposed to HPV L1 capsid protein are capable to penetrate the oocyte and transfer the virus into oocytes, in which viral genes are then activated and transcribed. These data show that sperm might function as vectors for HPV transfer into the oocytes, and open new perspectives on the role of HPV infection in males and are particularly intriguing in relation to assisted reproduction techniques.

Sperm viral infection and male infertility: focus on HBV, HCV, HIV, HPV, HSV, HCMV, and AAV

Chronic viral infections can infect sperm and are considered a risk factor in male infertility. Recent studies have shown that the presence of HIV, HBV or HCV in semen impairs sperm parameters, DNA integrity, and in particular reduces forward motility. In contrast, very little is known about semen infection with human papillomaviruses (HPV), herpesviruses (HSV), cytomegalovirus (HCMV), and adeno-associated virus (AAV). At present, EU directives for the viral screening of couples undergoing assisted reproduction techniques require only the evaluation of HIV, HBV, and HCV. However, growing evidence suggests that HPV, HSV, and HCMV might play a major role in male infertility and it has been demonstrated that HPV semen infection has a negative influence on sperm parameters, fertilization, and the abortion rate. Besides the risk of horizontal or vertical transmission, the negative impact of any viral sperm infection on male reproductive function seems to be dramatic. In addition, treatment with antiviral and antiretroviral therapies may further affect sperm parameters. In this review we attempted to focus on the interactions between defined sperm viral infections and their association with male fertility disorders. All viruses considered in this article have a potentially negative effect on male reproductive function and dangerous infections can be transmitted to partners and newborns. In light of this evidence, we suggest performing targeted sperm washing procedures for each sperm infection and to strongly consider screening male patients seeking fertility for HPV, HSV, and HCMV, both to avoid viral transmission and to improve assisted or even spontaneous fertility outcome.

Twenty-four-hour monitoring of scrotal temperature in obese men and men with a varicocele as a mirror of spermatogenic function

STUDY QUESTION How do day and night scrotal temperatures, spermatogenesis parameters, sex hormones and intratesticular perfusion in obese men and men with a varicocele compare with healthy controls? SUMMARY ANSWER Compared with healthy controls, 24-h monitoring of scrotal temperature in men with a varicocele and obese men showed higher temperatures and this condition was related to a significant alteration of spermatogenesis and stasis of testicular perfusion. WHAT IS KNOWN ALREADY Several studies have shown that increased scrotal temperature has dramatic effects on spermatogenesis. Scrotal hyperthermia by exposure to sauna is able to induce a significant alteration of sperm production. STUDY DESIGN, SIZE AND DURATION In a case-control study, data were collected over a period of 2 years from 60 subjects with risk factors for testicular heating and 20 healthy subjects who consecutively attended an andrology unit as participants in an infertility prevention program. PARTICIPANTS/MATERIALS, SETTING AND METHODS Forty subjects with a left varicocele, 20 obese men and 20 healthy subjects who served as controls, were evaluated for testicular volumes, sex hormones, sperm parameters, sperm aneuploidies, mean transit time (MTT) of intratesticular blood and 24-h scrotal temperature monitoring by a cutaneous thermochip. Subjects with a varicocele were further subgrouped on the basis of normo or oligozoospermia (VN and VO). Students t-test was used for statistical analysis. MAIN RESULTS AND THE ROLE OF CHANCE We found a significant increase in 24-h mean scrotal temperature in obese men and men with a varicocele compared with controls (both P < 0.01). This increase in scrotal temperature was associated with impaired sperm parameters and higher FSH plasma levels compared with controls. Dynamic evaluation of scrotal temperatures showed wide fluctuations in controls, but little variation in obese men and men with a varicocele. Men with VO had left and right increase in scrotal temperatures (the right was increased also versus VN, P < 0.01) (both P < 0.001). Men with VN showed a left scrotal temperature higher than controls (P < 0.01) and a right scrotal temperature no different from controls (34.92 ± 0.53 and 34.66 ± 0.65, respectively). Mean MTT values recorded in men with VO were significantly higher than men with VN and obese men (both P < 0.001). LIMITATIONS AND REASONS FOR CAUTION Different lifestyle, diet, occupation, stress level and environmental temperatures due to seasonal conditions are major limitations of this study. WIDER IMPLICATIONS OF THE FINDINGS Our data suggested for the first time that dynamic evaluation of scrotal temperatures seems to reflect alterations of testicular function and perfusion in obese men and men with a varicocele. In these clinical conditions, spermatogenic impairment and scrotal heating seem to be related to different mechanisms. The dynamic evaluation of scrotal temperature in subjects with risk factors for testicular heating could allow the identification of subjects needing treatment or a change in lifestyle. STUDY FUNDING/COMPETING INTERESTS No external funding was sought for this study, and the authors have no conflict of interest to declare.

Effect of Relaxin on Human Sperm Functions

Relaxin is a circulating hormone with functions in pregnancy, parturition, and other aspects of female reproduction. It is also secreted from the prostate gland into the seminal fluid; however, the role of relaxin in male reproduction is debated. Studies conducted in the past have suggested possible actions on human spermatozoa, but the data were contrasting. Here, we show that the relaxin receptor RXFP1 (Relaxin Family Peptide Receptor 1) is expressed in human spermatozoa, and it mainly localizes in the astrodome. In vitro studies on human sperm demonstrated that this hormone attenuates the natural decline in sperm motility and maintains higher mitochondrial activity and lower apoptosis level. Furthermore, relaxin induced an increase in sperm hyperactivation, intracellular calcium and cAMP, and acrosome reaction. These effects were abolished by the use of the specific anti-RXFP1 antibody. Relaxin concentrations were low in the blood (x ± SD, 0.16 ± 0.03 nM) and very high in the seminal plasma (x ± SD, 10.3 ± 4.0 nM), confirming its secretion mainly by the prostate. Taken together, these data demonstrate that relaxin influences positively many sperm functions linked to fertilizing ability, and it preserves sperm functionality, with possible practical value in assisted reproduction techniques.

How the human spermatozoa sense the oocyte: a new role of SDF1-CXCR4 signalling.

For fertilization to occur in mammals, ejaculated spermatozoa must reach the egg which, following ovulation has moved from the ovary into the Fallopian tube. Two active mechanisms of spermatozoa guidance have been shown in mammals: thermotaxis and chemotaxis. The identity of most of human spermatozoa chemoattractants is unknown, and herein we tested if SDF1 (chemokine stromal cell-derived factor-1) and its pathway is involved in spermatozoa chemotaxis. We found that SDF1 is expressed in the oocytes, endometrium and follicular fluid, as well as its specific receptor CXCR4 (chemokine CXC motif receptor 4) is expressed in the head of spermatozoa. By SDF1 gradient experiments, we stated that SDF1 is able to induce hyperactivation in spermatozoa leading to accumulation, to give rise to an increase in intracellular calcium concentration, and to preserve the mitochondrial status and not to induce acrosome reaction. Our findings suggest these phenomena could reflect spermatozoa chemotaxis, and that SDF1 action could represent an important event leading to egg fertilization, even if further studies regarding the link between spermatozoa accumulation and chemotaxis are mandatory. These data suggest that the SDF-1/CXCR4 signalling could be used to manipulate the human fertilization, to improve both the outcome of physiological or assisted reproduction, and to develop new contraceptive methods, by development of SDF1 or CXCR4 antagonist.

Molecular Karyotyping of Human Single Sperm by Array- Comparative Genomic Hybridization

No valid method is currently available to analyze the entire genome of sperm, including aneuploidies and structural chromosomal alterations. Here we describe the optimization and application of array-Comparative Genomic Hybridization (aCGH) on single human sperm. The aCGH procedure involves screening of the entire chromosome complement by DNA microarray allowing having a molecular karyotype, and it is currently used in research and in diagnostic clinical practice (prenatal diagnosis, pre-implantation genetic diagnosis), but it has never been applied on sperm. DNA from single human sperm isolated by micromanipulator was extracted, decondensed and amplified by whole-genome amplification (WGA) and then labeled, hybridized to BAC array, and scanned by microarray scanner. Application of this protocol to 129 single sperm from normozoospermic donors identified 7.8% of sperm with different genetic anomalies, including aneuploidies and gains and losses in different chromosomes (unbalanced sperm). On the contrary, of 130 single sperm from men affected by Hodgkin lymphoma at the end of three months of chemotherapy cycles 23.8% were unbalanced. Validation of the method also included analysis of 43 sperm from a man with a balanced translocation [46,XY,t(2;12)(p11.2;q24.31)], which showed gains and losses corresponding to the regions involved in the translocation in 18.6% of sperm and alterations in other chromosomes in 16.3% of sperm. Future application of this method might give important information on the biology and pathophysiology of spermatogenesis and sperm chromosome aberrations in normal subjects and in patients at higher risk of producing unbalanced sperm, such as infertile men, carriers of karyotype anomalies, men with advanced age, subjects treated with chemotherapy, and partners of couples with repeated miscarriage and repeated failure during assisted reproduction techniques.

Semen washing procedures do not eliminate human papilloma virus sperm infection in infertile patients

OBJECTIVE To determine the effectiveness of three sperm washing protocols for removing human papillomavirus (HPV)-infected cells from semen samples of infertile patients. DESIGN Cross-sectional clinical study. SETTING Andrology and microbiology sections at a university hospital. PATIENT(S) A group of 32 infertile patients positive for semen HPV, detected with polymerase chain reaction (PCR) and in-situ hybridization in sperm and exfoliated cells. INTERVENTION(S) Semen analysis and in-situ hybridization for HPV detection were performed before and after sperm washing, discontinuous Ficoll gradients, and swim-up protocols. Statistical analysis was performed with a two-tailed Students t-test. MAIN OUTCOME MEASURE(S) Evaluation of sperm parameters and presence of HPV, performed in semen samples before and after procedures of sperm selection. RESULT(S) All native samples showed the presence of infected sperm with a mean percentage of positivity (24.7% ± 8.9%) higher than exfoliated cells (13.8% ± 4.3%). Fifteen samples had HPV DNA on sperm and exfoliated cells. Sperm washing centrifugation showed no changes in the number of infected samples and in the percentage of infected cells. Ficoll and swim-up protocols induced a slight reduction in the number of infected samples (30 and 26, respectively). CONCLUSION(S) This study demonstrated that conventional sperm selection rarely eliminates HPV sperm infection. More attention should be paid to the reproductive health of infected patients because, not only can HPV be transmitted, but it may also have a negative effect on development of the fetus.

Role of zinc trafficking in male fertility: from germ to sperm

STUDY QUESTION What are the dynamics of zinc (Zn) trafficking in sperm, at the testicular, epididymal and ejaculate levels? SUMMARY ANSWER Zn transporters are peculiarly expressed in the cells of the germ line and Zn uptake is maximal at the post-epididymal phase, where Zn is involved in the regulation of sperm functions. WHAT IS KNOWN ALREADY Zn is known to influence several phases of sperm life, from germ cell development to spermiation. Zn trafficking across the membrane is allowed by specific families of transporters known as the ZnTs, which are involved in effluent release, and the Zips, which mediate uptake. STUDY DESIGN, SIZE, DURATION We enrolled 10 normozoospermic healthy participants in an infertility survey programme, as well as 5 patients affected by testicular germ cell cancer, and 18 patients presenting with obstructive azoospermia, without mutations of the CFTR gene, and undergoing assisted reproductive technologies. PARTICIPANTS/MATERIALS, SETTING, METHODS The research study was performed at our University Clinic. Semen samples, or biopsies or fine needle aspirates from the testis or epididymis, were obtained from each of the participants. Protein expression of main members of the ZnT and Zip families of Zn transporters was examined in human testis and epididymis samples by immunofluorescence. Quantification of sperm Zn content was performed by flow cytometry, atomic absorption spectrometry (AA) and autometallography. MAIN RESULTS AND THE ROLE OF CHANCE Intratubular cells of the germ line displayed a high redundancy of Zip family members involved in Zn uptake, while ZnT transporters were more represented in epididymis. Testicular and epididymal spermatozoa contained less Zn than ejaculated spermatozoa (2.56 ± 0.51 and 12.58 ± 3.16 versus 40.48 ± 12.71 ng Zn/10(6)cells, respectively). Gain of hypermotility and acrosomal reaction were significantly linked to the loss of Zn content in ejaculated spermatozoa. LIMITATIONS, REASONS FOR CAUTION This was an ancillary study performed on a small cohort of normozoospermic subjects. Although these results clarify the Zn trafficking during different phases of sperm life, no conclusive information can be drawn about the fertilizing potential of sperm, and the overall pregnancy outcomes, after Zn supplementation. WIDER IMPLICATIONS OF THE FINDINGS Our data disclose the dynamics of Zn trafficking during over the sperm lifespan. STUDY FUNDING/COMPETING INTEREST(S) No external funding was sought or obtained for this study. No conflict of interest is declared.

Sperm selected by both birefringence and motile sperm organelle morphology examination have reduced deoxyribonucleic acid fragmentation

OBJECTIVE To evaluate DNA fragmentation in single sperm selected by both birefringence and motile sperm organelle morphology examination (MSOME) with a single instrument. DESIGN Prospective study. SETTING University setting. PATIENT(S) Semen samples from 33 normozoospermic subjects. INTERVENTION(S) Birefringence and MSOME to distinguish different categories of sperm: nonbirefringent (category A), birefringent (category B), birefringent with nuclear vacuoles (category C), and birefringent with no nuclear vacuoles (category D). From each semen sample, sperm of any category were selected and further analyzed by TUNEL test. MAIN OUTCOME MEASURE(S) A total of 660 well-characterized sperm were evaluated for DNA fragmentation. RESULT(S) Category A showed a low percentage of sperm with normal MSOME results (19.4%) and high prevalence of DNA fragmentation (70.3%). Category B had 81.8% normal MSOME results, and in this group 31.8% had fragmentated DNA. Category C showed 31.8% and 92.6% DNA fragmentation in sperm with small and large nuclear vacuoles, respectively. Birefringent sperm with normal MSOME results and no vacuoles showed the lowest percentage of fragmented DNA (2.8%). CONCLUSION(S) Sperm selection by birefringence or MSOME alone had one-third probability to select sperm with fragmented DNA. The lowest percentage of DNA fragmentation was found in birefringent sperm with no nuclear vacuoles and normal MSOME results. We suggest combining both methods using a single microscope and selecting sperm without nuclear vacuoles to get sperm with a higher chance of having intact DNA.