Distribution of sperm counts in suspected infertile men

Probit plots of sperm concentration for 1711 suspected infertile men (those with azoospermia being excluded) were compared for the untransformed and loge-, square root- and cube root-transformed values. For the distribution of sperm concentrations, which was highly skewed towards low values, the square-root transformation produced the most normal (Gaussian) distribution. Loge and cube-root transformations caused skewing towards high values. Such treatment of the data should always be considered before using parametric statistical tests to make comparisons between sperm concentrations of groups of men.     

Human sperm chromosome complements in chemotherapy patients and infertile men

Our studies of human sperm karyotypes and interphase sperm analyzed by fluorescence in situ hybridization (FISH) have both yielded estimates of disomy frequencies of approximately 0.1% per chromosome with an overall aneuploidy frequency in human sperm of approximately 5%–6%. However, the distribution of aneuploidy in sperm is not even, as our data from sperm karyotypes and multicolour FISH analyses both demonstrate a significant increase in the frequency of aneuploidy for chromosome 21 and the sex chromosomes. We have studied men at increased risk of sperm chromosomal abnormalities including cancer patients and infertility patients. Testicular cancer patients were studied before and 2–13 years after chemotherapy (CT) with BEP (bleomycin, etoposide, cisplatin). Sperm karyotype analysis on 788 sperm demonstrated no significant difference in the frequency of numerical or structural chromosomal abnormalities post-CT vs pre-CT. Similarly, multicolour FISH analysis for chromosomes 1, 12, XX, YY and XY in 161,097 sperm did not detect any significant differences in the frequencies of disomy before and after treatment. However, recent evidence has suggested a significant increase in the frequency of disomy and diploidy during CT. We have found that infertile men, who would be candidates for intracytoplasmic sperm injection, have an increased frequency of chromosomally abnormal sperm karyotypes. Also, FISH analysis for chromosomes 1, 12, 13, 21, XX, YY and XY in 255,613 sperm demonstrated a significant increase in chromosomes 1, 13, 21, and XY disomy in infertile men compared with control donors. Received: 4 July 1998; in revised form: 7 September 1998 / Accepted: 8 September 1998     

Chromosome abnormalities in sperm from infertile men with asthenoteratozoospermia

Research over the past few years has clearly demonstrated that infertile men have an increased frequency of chromosome abnormalities in their sperm. These studies have been further corroborated by an increased frequency of chromosome abnormalities in newborns and fetuses from pregnancies established by intracytoplasmic sperm injection. Most studies have considered men with any type of infertility. However, it is possible that some types of infertility have an increased risk of sperm chromosome abnormalities, whereas others do not. We studied 10 men with a specific type of infertility, asthenozoospermia (poor motility), by multicolor fluorescence in situ hybridization analysis to determine whether they had an increased frequency of disomy for chromosomes 13, 21, XX, YY, and XY, as well as diploidy. The patients ranged in age from 28 to 42 yr (mean 34.1 yr); they were compared with 18 normal control donors whose ages ranged from 23 to 58 yr (mean 35.6 yr). A total of 201 416 sperm were analyzed in the men with asthenozoospermia, with a minimum of 10 000 sperm analyzed per chromosome probe per donor. There was a significant increase in the frequency of disomy in men with asthenozoospermia compared with controls for chromosomes 13 and XX. Thus, this study indicates that infertile men with poorly motile sperm but normal concentration have a significantly increased frequency of sperm chromosome abnormalities.     

Genetic diagnosis in infertile men with numerical and constitutional sperm abnormalities

Infertile men having numerical or structural sperm defects may carry several genetic abnormalities (karyotype abnormalities, Y chromosome microdeletions, cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations, androgen receptor gene mutations, and abnormalities seen in sperm cells) leading to this situation. First we aimed to investigate the relationship between the numerical and constitutional (morphological) sperm anomalies and the genetic disorders that can be seen in infertile males. Our other aim was to compare two different kinds of kits that we use for the detection of Y chromosome microdeletions. Sixty-three infertile males [44 nonobstructive azoospermic, 8 severe oligozoospermic, and 11 oligoasthenoteratozoospermic] were investigated in terms of somatic chromosomal constitutions and microdeletions of the Y chromosome. Sperm aneuploidy levels were analyzed by fluorescence in situ hybridization (FISH) in sperm cells obtained from the semen of six OAT patients. Microdeletion and sex chromosome aneuploidy (47,XXY) rates in somatic cells were found to be approximately 3.2% and 4.7%, respectively. Sperm aneuploidy rates were determined as 9%, 22%, and 47% in three patients out of six. Two of these three patients also had high rates of head anomalies in semen samples. High correlation was found between sperm aneuploidy rates and sperm head anomalies. Since the introduction of the assisted reproductive techniques for the treatment of severe male infertility, genetic tests and genetic counseling became very important due to the transmission of genetic abnormalities to the next generation. Thus in a very near future, for a comprehensive male infertility panel, it will be essential to include additional genetic tests, such as CFTR gene mutations, sperm mitochondrial DNA mutations, and androgen receptor gene mutations, besides the conventional chromosomal analyses, Y chromosome microdeletion detection, and sperm-FISH analyses.     

Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: oligozoospermia

Recently, intracytoplasmic sperm injection (ICSI) has been extremely successful for the treatment of male infertility. However, transmission of cytogenetic defects to offspring is a great concern. There are two types of cytogenetic problems in patients seeking ICSI; one is the transmission of genetic defects from patients with constitutional chromosomal abnormalities and the second is the generation of de novo defects in infertile men. Generally about 5.1% of infertile men have chromosomal abnormalities. Among such infertile men, men with severe spermatogenesis defects, including oligozoospermia and azoospermia, are subjects for ICSI. Therefore it is very important to obtain cytogenetic information in these infertile patients. Furthermore, oligozoospermic men with a normal somatic karyotype also have increased frequencies of sperm chromosome abnormalities. Oligozoospermia is usually associated with other sperm alterations, for example oligoasthenozoospermia, oligoteratozoospemia and oligoasthenoteratozoospermia. In this review, the relationship between sperm concentration and sperm aneuploidy frequencies has been analyzed. The inverse correlation between the frequency of sperm aneuploidy and concentration has been reported in extensive studies. Especially in severe oligozoospermia, a significantly higher frequency of sex chromosome aneuploidy has been observed and this has been corroborated in recent clinical outcome data of ICSI.     

Human sperm proteome: immunodominant sperm surface antigens identified with sera from infertile men and women.

The objective of this study was to identify those immunodominant sperm antigens recognized by antisperm antibodies (ASA) in the serum samples of infertile men and women. High-resolution two-dimensional gel electrophoresis was employed to separate human sperm proteins using isoelectric focusing or nonequilibrium pH gradient electrophoresis, followed by PAGE. Serum samples from 15 infertile male subjects and 6 infertile female subjects that contained ASA as assayed by the immunobead binding test (IBT) were analyzed by Western blotting followed by enhanced chemiluminescence (ECL). Serum samples from 10 fertile subjects (5 males and 5 females) that were ASA negative by IBT were used as controls. The ECL blots were analyzed by computer scanning to compare the immunoreactivity between serum samples from fertile and infertile subjects and to identify the antigens unique to the sera of the infertile subjects; 98 sperm auto- and iso-antigenic protein spots were recognized by sera from infertile males and females but not from fertile subjects. Based on vectorial labeling with 125I at the sperm surface, a subset of 6 auto- and iso-antigens was identified as possibly relevant to antibody-mediated infertility.     

Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: asthenozoospermia

The aim of aneuploidy evaluation in spermatozoa from patients presenting spermatogenesis defects is to identify a relationship between meiotic errors and quantitative or qualitative alterations of spermatogenesis. During the past ten years, the use of fluorescence in situ hybridization (FISH) has permitted the determination of the frequency of numerical chromosome aberrations in different clinical situations. It has been established that infertile males with reduced sperm count and a normal constitutional karyotype have a significantly high risk of aneuploidy in their spermatozoa particularly regarding sex chromosomes. Concerning sperm motility, the data are more controversial. However, patients of severe asthenozoospermia induced by specific morphological deformities involving sperm flagella have a significantly high risk of producing aneuploid spermatozoa.     

Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: teratozoospermia

Teratozoospermia is characterized by the presence of spermatozoa with abnormal morphology in sperm. This condition is frequently associated with infertility and intracytoplasmic sperm injection (ICSI) is frequently used as the treatment of choice. However, the use of ICSI has created consequential debate concerning the genetic risk for the offspring. Fluorescence in situ hybridization technique (FISH), allowing the specific identification of human chromosomes in sperm nuclei, has been used to study chromosome abnormalities in sperm from men with teratozoospermia and a normal karyotype. In this review, we present studies that have tried to determine if men with a normal blood karyotype but suffering from teratozoospermia present a higher aneuploidy frequency. The literature is limited to three forms of teratozoospermia. The first group consists of "polymorphic teratozoospermia", where a majority of spermatozoa display more than one type of abnormality. In this case, only a slight increase in aneuploidy frequency is observed, which cannot be differentiated from the results observed in oligo-astheno-teratozoospermia (OAT). The second group, named "globozoospermia", is characterized by round spermatic heads, absence of acrosome and disorganization of mid-piece and tail. In this case, some studies have shown a significant, but moderate, increase in the aneuploidy frequency for acrocentrics and sex chromosomes. The aneuploidy frequency remains low, also ICSI can be proposed to these patients, but few successes occur. The third group consists of "enlarged head teratozoospermia", where almost all spermatozoa have an enlarged head, multiple tail and abnormal acrosome. In this case a very high level of missegregation is observed, leading to nearly 100% aneuploidy. In this particular group, ICSI must be refuted, and patients have to be redirected to other possibilities, like sperm donation.     

Isolation and characterisation of two sperm membrane proteins recognised by sperm-associated antibodies in infertile men

Antisperm antibodies eluted from the surface of spermatozoa obtained from infertile men recognised several common epitopes. We tested whether these epitopes were relevant to fertility by isolating the immunodominant 37/36 and 19/18 protein zones. These protein zones were cut out of preparative slab gels and electro-eluted. The isolated proteins, P36 and P18, were used for biochemical characterisation and to produce specific antibodies in rabbits. The specific reactivity of P36 and P18 with WGA and AAL lectins, respectively, indicated the presence of lactosaminyl structures with sialic acid termini in P36 and of fucosylated residues in P18. Isoelectric focusing showed that the two proteins consist of several polypeptides. Some of these polypeptides were recognised by both human and rabbit antibodies: the pl of these epitopes was around 5.5 for P36 and 8.3-10.3 for P18. Rabbit antibodies detected the corresponding proteins on the sperm heads of methanol-fixed and of live acrosome-reacted spermatozoa. Anti-P36 antibodies bound mainly to the equatorial segment. They reduced the binding and, consequently, the penetration of zona-free hamster oocytes by human spermatozoa. Anti-P18 antibodies gave more diffuse staining of the acrosomal and post-acrosomal regions and reduced sperm-oocyte penetration without a significant effect on sperm binding. These results suggest that P36 and P18 antigens located in different compartments of the sperm head may participate in the sperm-oolemma interaction. We are currently investigating the physiological role of these antigens by sequencing the proteins isolated from the gels.     

Antioxidant levels in blood and seminal plasma and their impact on sperm parameters in infertile men

Excess reactive oxygen species (ROS) beyond the scavenging capacity of antioxidants leads to DNA damage and oxidation of lipoprotein components at the cellular and subcellular level. The oxidative stress (OS) adversely affects sperm function by altering membrane fluidity, permeability and impairs sperm functional competence. In the present study, the OS status in seminal plasma and blood serum in infertile men and its relationship with spermatozoa parameters have been investigated. Four groups of infertile men viz., oligozoospermic (n = 15), asthenozoospermic (n = 17), teratozoospermic (n = 19), and oligoasthenoteratozoospermic (n = 9), and healthy fertile controls (n = 40) have been analyzed for superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) in seminal plasma and blood serum. Significant correlation between blood serum SOD and sperm count has been observed in patients (p = 0.018) and controls (p = 0.021). Similarly, significant correlation between blood serum GSH and sperm progressive motility in patients (p = 0.036) and controls (p = 0.029) is observed. The low seminal MDA is associated with increase in sperm progressive motility in patients (p = 0.039) and controls (p = 0.028). Positive correlation is found between increased seminal MDA levels and abnormal sperm morphology in both patients and controls (r = 0.523, p = 0.029; r = 0.612, p = 0.034 respectively). Correlations between blood SOD and sperm count and between blood GSH levels and progressive motility suggest that these can be important biochemical markers in assaying the sperm count and motility. A negative correlation of motility with seminal MDA indicates that sperm membrane lipid peroxidation affects the fluidity and thus mobility of sperm axoneme. This affects functional competence of the sperm and acts like a biological safeguard. The results of the present study suggest the prospects of using the blood serum and seminal plasma antioxidants as a valuable tool to evaluate the sperm reproductive capacity and functional competence.     

Two-dimensional high-performance liquid chromatographic determination of 5-hydroxyindoleacetic acid and homovanillic acid in urine

The biomedically and neurochemically important compounds 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) have been simultaneously determined in human urine after reverse-phase two-dimensional high-performance liquid chromatography. A 10-fold-diluted urine sample (20 microliters) is first separated on a C18 column (30 X 0.39 cm) using an 85% pH 6.0 phosphate buffer/15% methanol solvent system. The elution volume containing both 5-HIAA and HVA (Rt approximately 3 min) is collected. Recoveries (mean +/- SD) for this purification step, which is monitored using fluorometric detection, were usually above 90%. After acidification of the approximately 2 ml collected fraction, 100 microliters is reinjected on a C18 column and separated (Rt: 5-HIAA, 4 min; HVA 5.5 min) using an 80% pH 3.5 phosphate buffer/20% methanol mobile phase. The compounds are determined by flow-through amperometry with absolute detection limits of approximately 25 pg. Both 5-HIAA and HVA are well resolved from other electroactive species present and are easily determined at normal and greatly reduced concentrations in human urine.