Germ-cell nondisjunction in testes biopsies of men with idiopathic infertility

Impact of a mild scrotal heating on sperm chromosomal abnormality, acrosin activity and seminal alpha-glucosidase in human fertile males

The aim of this study was to observe sperm aneuploidy, DNA integrity, seminal alpha-glucosidase (NAG) and acrosin activity (AA) under testicular heat stress (SH). Spermatozoa were obtained from 30 healthy adult volunteers subjected to scrotal warming at 43°C for 30-40 min on two successive days per week for 3 months between February 2012 and September 2016. Aniline blue (AB), acridine orange (AO) staining, TUNEL assay and FISH analysis to evaluate sperm function, sperm DNA integrity and chromosomal abnormalities were carried on before, during and after SH. Sperm AA and NAG was measured by microplate reader. The mean parameters of sperm parameters, AA and NAG were significantly decreased. In contrast, the mean percentage of sperm DNA fragmentation and the proportion of aneuploidy of chromosomes 13, 18, 21, X and Y were significantly increased for spermatozoa collected during SH versus before SH (p < .01-.001). After stopping scrotal heating for 3 months, most parameters were completely restored to pre-SH levels. Sperm parameters, sperm DNA integrity, chromosomes, AA and NAG are affected by scrotal exposure to constant SH temperatures several degrees over normal physiological temperature, and after treatment, these parameters were reversibly restored to the level before SH in adult men.

Chromosome abnormalities in embryos derived from microsurgical epididymal sperm aspiration and testicular sperm extraction

OBJECTIVE

To evaluate the patterns of chromosome abnormalities in embryos derived from intracytoplasmic sperm injection (ICSI) in microsurgical epididymal sperm aspiration (MESA) or testicular sperm extraction (TESE) in comparison to embryos that are derived from naturally ejaculated (EJAC) patients.

MATERIALS AND METHODS

Male partners with azoospermia who required MESA or TESE for ICSI were studied for chromosomal abnormalities. The ICSI patients with EJAC sperm served as the control group. Preimplantation genetic diagnosis (PGD) was performed by fluorescence in situ hybridization (FISH). Chromosome abnormalities were categorized as polyploidy, haploidy, aneuploidy, and complex abnormality (which involves more than two chromosomes). Fertilization, embryo development, and patterns of chromosome abnormalities were accessed and evaluated.

RESULTS

There was no difference between the MESA, TESE, and EJAC patient groups in the rates of fertilization and pregnancy and the percentages of euploid embryos. In all three groups, less than one-half of the embryos for each group were normal (41 ± 31%, 48 ± 38%, and 48 ± 31% in MESA, TESA, and EJAC, respectively). Complex chromosomal abnormality was significantly more frequent in the MESA group than in the EJAC group (48.3% vs. 26.5%, respectively; p < 0.001). Furthermore, the overall pattern of chromosomal aneuploidy was similar among all three studied groups.

CONCLUSION

We suggest that MESA and TESE, followed by ICSI and PGD, appear to be acceptable approaches for treating men with severe spermatogenesis impairment.

Fluorescent in situ hybridization of human sperm: diagnostics, indications, and therapeutic implications

Male factor infertility is a relatively common condition, affecting at least 6% of men of reproductive age. Typically, men with unknown genetic abnormalities resort to using assisted reproductive techniques (ART) to achieve their reproductive goals. Infertile men who father biological children using ART could have a higher incidence of aneuploidy, which is a deviation from the normal haploid or diploid chromosomal state. Aneuploidy can be evaluated using fluorescent in situ hybridization (FISH), a cytogenetic assay that gives an estimate of the frequencies of chromosomal abnormalities. The chromosomes that are generally analyzed in FISH (13, 18, 21, X, and Y) are associated with aneuploidies that are compatible with life. The technique is indicated for various reasons but primarily in [1] men who despite normal semen parameters suffer recurrent pregnancy loss, and [2] men with normal semen parameters, who are undergoing in vitro fertilization but still experiencing recurrent implantation failure. As a screening tool, the technique can help in reproductive and genetic counseling of affected couples, or those who have previously experienced failure of ART. A qualitative analysis of FISH study results allows couples to make informed reproductive choices. Given the increasing clinical use of FISH in various infertility diagnoses, and the development of novel adjunct technologies, one can expect much progress in the areas of preimplantation genetic screening, diagnostics, and therapeutics.

A comparison of ejaculated and testicular spermatozoa aneuploidy rates in patients with high sperm DNA damage

Testicular spermatozoa are utilized to achieve pregnancy in couples with severe male factor infertility. Several studies suggest that aneuploidy rates in spermatozoa are elevated at the testicular level in infertile patients compared to ejaculates of normal controls. However, essential data regarding aneuploidy rates between ejaculated and testicular spermatozoa in the same individuals is lacking. The purpose of our study was to compare aneuploidy rates at the testicular and post-testicular level from the same patients with persistently high sperm DNA damage. Ejaculates and testicular biopsies were obtained from eight patients with persistently high DNA damage (>30%). Both ejaculated and testicular samples were analyzed for sperm DNA damage and sperm aneuploidy for chromosomes 13, 18, 21, X, and Y. In addition, semen samples from ten normozoospermic men presenting for fertility evaluation served as a control group. A strong correlation between the alteration of spermatogenesis and chromatin deterioration was observed in our study. In the same individuals, testicular samples showed a significantly lower DNA damage compared to ejaculated spermatozoa (14.9% ± 5.0 vs. 40.6% ± 14.8, P<0.05), but significantly higher aneuploidy rates for the five analyzed chromosomes (12.41% ± 3.7 vs. 5.77% ± 1.2, P<0.05). While testicular spermatozoa appear favourable for ICSI in terms of lower DNA damage, this potential advantage could be offset by the higher aneuploidy rates in testicular spermatozoa.

The use of fluorescent in situ hybridization in male infertility

Male factors are implicated in up to 50% of couples being evaluated and treated for infertility with advanced assisted reproductive technologies. Genetic abnormalities, including sperm chromosome aneuploidy as well as structural aberrations, are one of the major causes of infertility. The use of chromosome-specific DNA probes labeled with fluorochromes, particularly the combination with multiple probes, has been used to indirectly study the sperm chromosome by fluorescent in situ hybridization (FISH). Clinically, this technique is also used to assess the sperm of men recovering from gonadotoxic treatment. Recent advances in this technology facilitate the evaluation of sperm aneuploidy. Sperm FISH is a widely used screening tool to aid in counseling couples with severe male factor infertility, especially in cases of prior repeated in vitro fertilization/intracytoplasmic sperm injection failure or recurrent pregnancy loss. Automation of FISH imaging and analysis, as well as the development of emerging techniques such as comparative genomic hybridization, will all contribute to the promise of future diagnostic approaches aimed at improving the quality, ease, and efficiency of aneuploidy analysis.

Computerized cell-scanning system for evaluating human spermatogenesis in non-obstructive azoospermic patients

There may be incompatibility between testicular histopathological evaluation and testicular sperm extraction (TESE) outcome. Assessment for sperm presence and different pathological disturbances of non-obstructive azoospermia (NOA) remains challenging. An assay for maximal sampling and accurate identification of testicular cells from NOA patients undergoing TESE and autopsied fertile controls was developed. Testicular cells stained and scanned automatically for morphology underwent fluorescence in-situ hybridization using centromeric probes for chromosomes X, Y and 18 after destaining. Cells were automatically classified according to ploidy, and ratios of haploid cells and autosomal (18) and sex-chromosome bivalent rates were calculated. Identification of testicular cells in suspension enabled prediction of spermatogenesis in seven of eight Sertoli-cell-only syndrome patients. Haploid/diploid cell ratios were 67.6:32.2 for controls and 9.6:90.4 for patients. Both autosomal (18) and sex-chromosome bivalents were present in patients (4.1 ± 5.82%) and controls (19.7 ± 8.95%). Few tetraploid pachytene spermatocytes were observed. More secondary spermatocytes with NOA showed two distinct signals for chromosome 18 (27.9 ± 32.69%) compared with controls (0.4 ± 0.35%). The computerized cell-scanning system enables simultaneous application of morphology and chromosome analysis of testicular cells, which enhance assessing different pathological disturbances and estimating the likelihood of a successful second TESE procedure.

Use of diagnostic testing to detect infertility

The evaluation of the infertile male continues to be a clinical challenge of increasing significance with considerable emotional and financial burdens. Many physiological, environmental and genetic factors are implicated; however, the etiology of suboptimal semen quality is poorly understood. This review focuses on the diagnostic testing currently available, as well as future directions that will be helpful for the practicing urologist and other clinicians to fully evaluate the infertile male.

Contemporary concepts in the evaluation and management of male infertility

Infertility in men is a common condition. At the core of the medical evaluation of the male partner in a couple who are unable to conceive is the history and physical examination. Special attention should be directed to the patient's developmental history and any use of testosterone products. The physical examination focuses on the genitals, and includes assessments of the size and consistency of the testicles, epididymis, vas deferens, and presence of varicoceles. Although many sophisticated tests are available, semen analysis is still the most important diagnostic tool used to assess fertility, and includes parameters such as sperm count, motility and viability. Treatment of male factor infertility can involve targeted agents, in the case of specific conditions such as hypogonadotropic hypogonadism, or it can be empirical-using medical therapy or assisted conception techniques-for patients in whom no underlying cause has been identified. Although an all-encompassing treatment for male factor infertility has not yet been developed, the field offers many promising avenues of research.

Numerical chromosome abnormalities are associated with sperm tail swelling patterns

OBJECTIVE

To assess whether the differential sperm tail swelling patterns observed following hypo-osmotic shock are useful in discriminating normal sperm from aneuploid sperm.

DESIGN

Prospective study.

SETTING

University research setting.

INTERVENTION(S)

Fluorescence in situ hybridization (FISH) was combined with hypo-osmotic swelling for a simultaneous assessment of aneuploidy and viability in human spermatozoa.

MAIN OUTCOME MEASURE(S)

FISH for chromosomes 1, 13, 18, 21, X, and Y after hypo-osmotic stress was used to investigate the distribution of sperm aneuploidy related to sperm-tail swelling patterns. A total of 16,473 sperm cells were scored from three normal fertile donors and six oligoasthenoteratozoospermic (OAT) patients.

RESULT(S)

There was a 17.2-fold decrease in the frequency of total aneuploidy in the sperm with a tail-tip swelling pattern compared with the initial nonselected sperm in the OAT patients. Strikingly, when the sperm with tail-tip swelling patterns were screened from the patients, the frequency of total aneuploidy was actually lower by a factor of four than in the nonselected sperm from fertile donors.

CONCLUSION(S)

The sperm cells with tail-tip swelling patterns are related to a low frequency of aneuploidy.

In vitro spermatogenesis as a method to bypass pre-meiotic or post-meiotic barriers blocking the spermatogenetic process: genetic and epigenetic implications in assisted reproductive technology

Pregnancies achieved by assisted reproduction technologies and particularly by ooplasmic injections of either in vivo or in vitro generated immature male germ cells are susceptible to genetic risks inherent to the male population treated with assisted reproduction and additional risks inherent to these innovative procedures. The documented, as well as the theoretical risks, are discussed in this review. These risks represent mainly the consequences of genetic abnormalities underlying male infertility and may become stimulators for the development of novel approaches and applications in the treatment of infertility. Recent data suggest that techniques employed for in vitro spermatogenesis, male somatic cell haploidization, stem cell differentiation in vitro and assisted reproductive technology may also affect the epigenetic characteristics of the male gamete, the female gamete, or may have an impact on early embryogenesis. They may be also associated with an increased risk for genomic imprinting abnormalities. Production of haploid male gametes in vitro may not allow the male gamete to undergo all the genetic and epigenetic alterations that the male gamete normally undergoes during in vivo spermatogenesis.

Genetic and epigenetic risks of intracytoplasmic sperm injection method

Pregnancies achieved by assisted reproduction technologies, particularly by intracytoplasmic sperm injection (ICSI) procedures, are susceptible to genetic risks inherent to the male population treated with ICSI and additional risks inherent to this innovative procedure. The documented, as well as the theoretical, risks are discussed in the present review study. These risks mainly represent that consequences of the genetic abnormalities underlying male subfertility (or infertility) and might become stimulators for the development of novel approaches and applications in the treatment of infertility. In addition, risks with a polygenic background appearing at birth as congenital anomalies and other theoretical or stochastic risks are discussed. Recent data suggest that assisted reproductive technology might also affect epigenetic characteristics of the male gamete, the female gamete, or might have an impact on early embryogenesis. It might be also associated with an increased risk for genomic imprinting abnormalities.

Analysis of early meiotic events and aneuploidy in nonobstructive azoospermic men: a preliminary report

OBJECTIVE

To study the events of spermatogenesis in azoospermic men by examining meiosis I spermatocytes and postmeiotic spermatozoa.

DESIGN

A preliminary analysis of synaptonemal complex (SC), recombination, and chromosomal constitution (meiotic and postmeiotic) in testicular tissue.

SETTING

Academic research environment.

PATIENT(S)

Three men with nonobstructive azoospermia and one fertile man (vasectomy reversal: control) who underwent testicular sperm extraction in preparation for intracytoplasmic sperm injection (ICSI).

INTERVENTION(S)

Testicular tissue specimens were processed by immunofluorescence analysis with antibodies against proteins associated with SC and recombination events. Fluorescence in situ hybridization (FISH) for chromosomes X, Y, and 18 was done on spermatocytes in prophase I and on postmeiotic spermatozoa.

MAIN OUTCOME MEASURE(S)

SC formation and recombination in meiosis I, aneuploidy.

RESULT(S)

The number of autosomal recombination foci in each patient was not statistically significantly different from control. The frequencies of XY bivalents with at least one recombination focus were statistically similar in the patients and control (74.2% vs. 82.6%, respectively). All observed cells in pachytene had normal XY constitutions. In spite of this, the rate of sex-chromosome aneuploidy in spermatozoa was statistically significantly higher in the patients compared with the control (1.89% vs. 0.83%).

CONCLUSION(S)

The combination of immunocytologic technology with FISH can add a level of precision in etiologic investigations of severe male factor infertility: men can have normal pairing and recombination but still yield aneuploid spermatozoa.

Protein phosphatase 1cgamma is required in germ cells in murine testis

The protein phosphatase 1cgamma (PP1cgamma) gene is required for spermatogenesis. Males homozygous for a null mutation are sterile, and display both germ cell and Sertoli cell defects. As these two cell types are physically and functionally intimately connected in the testis, the question arises as to whether the primary site of PP1cgamma action is in Sertoli cells, germ cells, or both. We generated chimeric males by embryo aggregation to test whether wild type Sertoli cells are capable of rescuing mutant germ cells. To distinguish between the desired XY-XY chimeras and uninformative XX-XY chimeras, we designed an adaptation of the single nucleotide primer extension (SNuPE) assay. None of the XY-XY chimeras sired pups derived from mutant germ cells, indicating that the protein is required in germ cells for production of functional sperm. Analysis of a chimeric testis revealed intermediate phenotypes when compared with PP1cgamma-/- testes, suggestive of cell nonautonomous effects. We conclude that PP1cgamma is required in a cell autonomous fashion in germ cells. There may be an additional cell nonautonomous role played by this gene in testes, possibly mediated by defective signaling between germ cells and Sertoli cells.

Genetic disorders and infertility

Many aspects of male fertility are influenced by genetics. Over 150 genes have been shown to be associated with infertility in mouse models, although translation of these findings to human male infertility has been slow. Nevertheless, it is likely that a significant number of these gene deletions may be associated with human infertility. There is much that we do not understand about the molecular basis of human male infertility; patients should be advised of this caveat. Genetic disorders in humans can lead to impaired spermatogenesis, defective sperm function, and defects in delivery of sperm. It is critical for the urologist who evaluates and treats infertile couples to have a working knowledge of these disorders. An understanding of the genetic basis of male infertility allows for the appropriate counseling of patients about treatment options and risks to their potential offspring.

Chromosomal abnormalities in embryos derived from testicular sperm extraction

OBJECTIVE

To compare the rate of chromosome abnormalities in embryos obtained from karyotypically normal patients with nonobstructive azoospermia undergoing testicular sperm extraction (TESE) to those from patients undergoing intracytoplasmic sperm injection (ICSI) with ejaculated sperm.

DESIGN

Retrospective analysis.

SETTING

IVF centers.

PATIENT(S)

Male partners had either nonobstructive zoospermia or oligospermia.

INTERVENTION(S)

Preimplantation genetic diagnosis. Chromosome enumeration was performed by fluorescence in situ hybridization (FISH). Embryos classified as abnormal were reanalyzed to study mosaicism.

MAIN OUTCOME MEASURE(S)

Chromosome abnormalities in embryos.

RESULT(S)

Embryos from ICSI cycles with ejaculated sperm (group 1) were 41.8% normal, 26.2% aneuploid, and 26.5% mosaic. In contrast, the embryos from ICSI cycles with TESE for nonobstructive azoospermia (group 2) were 22% normal, 17% aneuploid, and 53% mosaic. The difference in mosaicism rate between the two groups of embryos was highly significant.

CONCLUSION(S)

The present study results indicate a high incidence of mosaicism in embryos derived from TESE in men with a severe deficit in spermatogenesis. Sperm derived from TESE for nonobstructive azoospermia may have a higher rate of compromised or immature centrosome structures leading to mosaicism in the embryo.

Results of preimplantation genetic diagnosis in patients with Klinefelter's syndrome

With the application of preimplantation genetic diagnosis (PGD), a possible genetic contribution of spermatozoa obtained from 47,XXY non-mosaic Klinefelter patients on preimplantation embryos was analysed in eight couples. Interpretable fluorescence in-situ hybridization results were obtained for 28 out of 33 embryos biopsied (84.8%) and 23 blastomeres were analysed for chromosomes 13, 18, 21, X and Y. Nine out of 23 embryos were diagnosed as abnormal (39.1%). Five out of nine contained sex chromosome abnormalities (55.5%). Two were diagnosed as 47,XXY and three were found to have monosomy X. Besides sex chromosomal abnormalities, other abnormalities detected were haploidy, triploidy, monosomy 13, monosomy 18 and trisomy 13. Five blastomeres were analysed for sex chromosomes only and all of them were found to be normal. Overall, the rate of sex chromosome abnormality in biopsied embryos was found to be 17.8% (5/28). Moreover, among 33 embryos biopsied, five of the eight zygotes, which were classified as a poor prognosis group according to pronuclear morphology scoring, showed an impaired growth profile after biopsy and were found to be chromosomally abnormal. Elimination of abnormal embyos and transfer of normal ones resulted in four pregnancies in eight cycles (50%). Two pregnancies, one singleton and one twins resulted in healthy births. Two pregnancies, one singleton and one twins are continuing beyond the second trimester. These results show that there is in fact elevated chromosomal abnormality for both sex chromosomes and autosomes in embryos developed from Klinefelter males. Furthermore together with PGD, embryo scoring according to pronuclear morphology can give additional benefit for selecting chromosomally abnormal embryos. Therefore, PGD should be recommended in cases with Klinefelter's syndrome and this information should be discussed with the couple when genetic counselling is given.

Understanding new genetics of male infertility

PURPOSE

Greater than 10% of couples are unable to achieve pregnancy. In at least 30% to 50% of these infertility cases a male factor abnormality is involved. Genetic defects are believed to be the cause of a significant percent of these abnormalities. In fact, defects causing infertility, such as chromosomal disorders and congenital hypothalamic-pituitary-gonadal axis syndromes, have long been recognized. With the development of gene targeting technologies in animal models many genes required for male fertility in animals are known, contributing to our understanding of the etiology of this important health problem. We present not only recognized genetic disorders associated with male infertility, but also its emerging and previously unrecognized genetic etiologies.

MATERIALS AND METHODS

This review is organized to enable the reader to recognize promptly the major types of genetic defects associated with male infertility, their clinical characteristics and appropriate therapeutic approaches. Due to the explosion of current knowledge in this field and to length restrictions the discussion of genetic defects is concise, referencing predominantly review articles relevant to the topic.

RESULTS

Assisted reproductive technologies for overcoming sterility resulting from unrecognized etiologies may have important potential consequences for infertile couples and their offspring.

CONCLUSIONS

Familiarity with the genes associated with male infertility is essential for the urologist to better understand, diagnose and treat the male factor couple.

Chromosome analysis of epididymal and testicular spermatozoa in patients with azoospermia

Azoospermic patients can now father children once spermatozoa have been retrieved from the epididymis or the testis. However, there are concerns about the risk of chromosomal abnormalities since an increase in sperm aneuploidy rate has been reported in samples from patients with abnormal sperm parameters. The purpose of this study was therefore to evaluate the sperm aneuploidy and diploidy rates for chromosomes 8, 12, 18, X and Y in spermatozoa extracted from the epididymes (n=10) or the testes (n=6) of patients with azoospermia. Ejaculated spermatozoa of healthy men (n=14) served as control. Epididymal and testicular spermatozoa had an aneuploidy rate significantly higher than that found in ejaculated spermatozoa. The aneuploidy and diploidy rates of testicular spermatozoa were higher, but not significantly different, than those found in epididymal spermatozoa. This study has shown that azoospermic patients have an increased sperm aneuploidy rate. They should therefore be given appropriate genetic counselling before entering in-vitro fertilisation programs.

The rate of aneuploidy is altered in spermatids from infertile mice

BACKGROUND

It is now possible for infertile males to father their own genetic children through the technique of ICSI. This prospect has consequently prompted several investigations into the quality of sperm being retrieved from infertile males. One potential risk is the use of aneuploid sperm or spermatids, which might then be transferred to the fertilized oocyte.

METHODS

In this investigation, aneuploidy of spermatids was assessed through immunocytochemistry using antibodies directed against chromosome centromeric regions and complexes. Three different types of infertile male mice with phenotypes closely resembling those described in human non-obstructive azoospermia [PP1cgamma-deficient mice, CREM-deficient mice and C57BL/6J.MAC-17(0--23) mice] were examined for chromosome numbers by counting the number of kinetochores in round spermatids using a CREST antiserum.

RESULTS

PP1cgamma(-/-) and CREM(-/-) spermatids from infertile mice showed highly significant elevated levels in the rate of aneuploidy compared with wild-type animals (P < 0.0001). Thus infertile males with independent genetic mutations resulting in different histopathologies showed a high risk in the level of aneuploidy in their spermatids.

CONCLUSIONS

These results suggest that impaired spermatogenesis may lead to production of aneuploid gametes. Analysis of aneuploidy in gametes from infertile men, coupled with appropriate genetic counselling, is recommended prior to ICSI.

Chromosome analysis of epididymal and testicular sperm in azoospermic patients undergoing ICSI

BACKGROUND

Although ICSI provides a way of treating azoospermic men, concern has been raised about the potential risk for transmission of genetic abnormalities to the offspring. We quantified the incidence of chromosomal abnormalities in epididymal and testicular sperm retrieved from azoospermic patients undergoing ICSI.

METHODS

Individual testicular sperm were collected from testicular biopsies with an ICSI pipette, and epididymal sperm were retrieved by microsurgical epididymal sperm aspiration. Samples were processed by fluorescent in-situ hybridization (FISH) for chromosomes 18, 21, X and Y and the results compared with those from normal ejaculated samples.

RESULTS

The overall aneuploidy rate of 11.4% in men with non-obstructive azoospermia was significantly higher (P = 0.0001) than the 1.8% detected in epididymal sperm from men with obstructive azoospermia and also the 1.5% found in ejaculated sperm. No significant difference was found between the epididymal and ejaculated samples. When the chromosomal abnormalities were analysed, gonosomal disomy was the most recurrent abnormality in both obstructive and non-obstructive azoospermic patients, while autosomal disomy was the most frequent in ejaculated sperm.

CONCLUSIONS

Sperm of non-obstructive azoospermic men had a higher incidence of chromosomal abnormalities, of which sex chromosome aneuploidy was the most predominant. Genetic counselling should be offered to all couples considering infertility treatment by ICSI with testicular sperm.

Increased chromosome X, Y, and 18 nondisjunction in sperm from infertile patients that were identified as normal by strict morphology: implication for intracytoplasmic sperm injection

OBJECTIVE

To determine the incidence of nondisjunction for chromosomes X, Y, and 18 using fluorescence in situ hybridization (FISH) on morphologically normal sperm from infertile men who are candidates for ICSI.

DESIGN

After standard hematoxylin staining, sperm with normal morphology were identified using Kruger's strict morphology criteria. The location of each normal-appearing sperm was recorded using an electronic microstage locator. Slides were subsequently subjected to FISH for detection of chromosomes X, Y, and 18 (control probe). Nuclei were relocated and analyzed under the fluorescent microscope.

SETTING

University-affiliated IVF and intracytoplasmic sperm injection program.

PATIENT(S)

Men classified as infertile on the basis of abnormal strict morphology (<4% by Kruger's criteria). For controls, normal fertile men (n=6) were also analyzed.

INTERVENTION(S)

Semen smears were obtained retrospectively from infertile (n=8) and fertile (n=6) men.

MAIN OUTCOME MEASURE(S)

Ploidy of each cell was determined according to the number of signals detected for each probe.

RESULT(S)

Approximately 100-150 morphologically normal sperm were identified and located in each case. Subsequent FISH analysis of these normal sperm showed aneuploidy to range from 1.8% to 5.5% in the infertile group as compared with 0 to 2.6% among the control fertile group. Statistically significant differences in the incidence of aneuploidy for the sex chromosomes as well as for all three (X, Y, and 18) chromosomes was observed.

CONCLUSION(S)

Although 95% to 98% of the sperm were found to be normal for X, Y, and 18, our findings show that infertile couples undergoing ICSI are likely to be at an increased risk for having a genetically abnormal conceptus as compared with the fertile controls. These results demonstrate that normal morphology is not an absolute indicator for the selection of genetically normal sperm. Hence, observed pregnancy failures among ICSI patients may in part be due to the selection of aneuploid sperm.

Evaluation of meiotic impairment of azoospermic men by fluorescence in situ hybridization

OBJECTIVE

To identify predictive criteria for the existence of spermatogenesis in nonobstructive azoospermic men.

DESIGN

Prospective study.

SETTING

Andrology laboratory at a teaching hospital.

PATIENT(S)

Twenty-two azoospermic men were divided into three groups by qualitative testicular histopathology and the presence of spermatozoa in minced biopsies.

INTERVENTION(S)

Testicular biopsies evaluation.

MAIN OUTCOME MEASURE(S)

The presence of spermatozoa and/or mature spermatids, the percentage of sex vesicle formation (X and Y chromosomes in proximity), and the pairing of the two 18 homologous chromosomes.

RESULT(S)

Spermatozoa and mature spermatids were found in 17 study patients. Whenever few mature spermatids and/or spermatozoa were found, the rates of X-Y and 18 bivalents were significantly higher (mean +/- SD, 73% +/- 13. 3% and 91% +/- 7.1%) than those in cases of spermatocyte maturation arrest (23% +/- 8.0% and 60% +/- 11.8%, respectively).

CONCLUSION(S)

Pairing of chromosomes during meiosis is apparently related to the progression of spermatogenesis. Consequently, high rates of bivalent formation increase the prospect of focal spermatogenesis in the testis, despite the failure to identify mature spermatids in the specific testicular biopsy under examination.

Male infertility: recent advances and a look towards the future

The past decade has witnessed clinical and basic scientific advances that have revolutionized the diagnosis and treatment of the infertile male. Advances in the clinic and laboratory have resulted in men who were previously thought to be hopelessly infertile, but who are now able to conceive their own biologic offspring. In the future, we believe that the laboratory will continue to play a key role in advancing our ability both to diagnose and to treat the infertile male. We summarize here some of the major advances of the past decade that have influenced our treatment and our understanding of the etiology of male infertility. When possible, clinical innovations and advances in basic science are discussed in combination in order to emphasize the translational importance of reproductive research.