The effects of age on DNA fragmentation, the condensation of chromatin and conventional semen parameters in healthy nonsmoking men exposed to traffic air pollution.

BACKGROUND: Numerous studies have investigated age-based declines in semen traits, but the impact of paternal age on semen parameter values remains inconclusive. OBJECTIVES: The aim of this study was to detect an impact of age on semen quality was studied in healthy nonsmoking men exposed to traffic air pollution. METHODS: Semen samples from 150 Prague City policemen aged 23 to 63 years were examined for standard semen parameters, sperm DNA fragmentation and high DNA stainability. RESULTS: A significant positive correlation was found between age and %DFI (r = .359, P < .001), and negative correlations were found between age and sperm vitality (r = -.247, P < .001), the % acrosome-intact sperm (r = -.202, P = .013) and the % normal sperm heads (r = -.204, P = .012). A weak but significant negative correlation was found for high DNA stainability (% HDS) vs age (r = -.161, P = .050). No significant correlation was detected between male age and the other investigated semen quality parameters. At ages of 23 to 30, 31 to 40, 41 to 50, and 51 to 63 years, the mean %DFI values were 12.7 ± 7.18, 14.7 ± 7.42, 19.6 ± 11.25, and 34.2 ± 15.08, respectively. CONCLUSION: Our study shows a strong relationship (P < .001) between the age of men and sperm DNA fragmentation in an occupational cohort at risk of exposure to heavy traffic-related air pollution in a large city center.

Comprehensive meiotic segregation analysis of a 4-breakpoint t(1;3;6) complex chromosome rearrangement using single sperm array comparative genomic hybridization and FISH.

Complex chromosomal rearrangements (CCR) represent rare structural chromosome abnormalities frequently associated with infertility. In this study, meiotic segregation in spermatozoa of an infertile normospermic carrier of a 4-breakpoint t(1;3;6) CCR was analysed. A newly developed array comparative genomic hybridization protocol was used, and all chromosomes in 50 single sperm cells were simultaneously examined. Three-colour FISH was used to analyse chromosome segregation in 1557 other single sperm cells. It was also used to measure an interchromosomal effect; sperm chromatin structure assay was used to measure chromatin integrity. A high-frequency of unbalanced spermatozoa (84%) was observed, mostly arising from the 3:3 symmetrical segregation mode. Array comparative genomic hybridization was used to detect additional aneuploidies in two out of 50 spermatozoa (4%) in chromosomes not involved in the complex chromosome rearrangement. Significantly increased rates of diploidy and XY disomy were found in the CCR carrier compared with the control group (P < 0.001). Defective condensation of sperm chromatin was also found in 22.7% of spermatozoa by sperm chromatin structure assay. The results indicate that the infertility in the man with CCR and normal spermatozoa was caused by a production of chromosomally unbalanced, XY disomic and diploid spermatozoa and spermatozoa with defective chromatin condensation.

Balanced chromosomal translocations in men: relationships among semen parameters, chromatin integrity, sperm meiotic segregation and aneuploidy.

PURPOSE: To analyse relationships between semen parameters, sperm chromatin integrity and frequencies of chromosomally unbalanced, disomic and diploid sperm in 13 Robertsonian and 37 reciprocal translocation carriers and to compare the results with data from 10 control donors. METHODS: Conventional semen analysis, Sperm Chromatin Structure Assay and FISH with probes for chromosomes involved in the individual translocations and for chromosomes X, Y, 7, 8, 13, 18 and 21. RESULTS: Normal semen parameters were found in 30.8 % of Robertsonian and 59.5 % of reciprocal translocation carriers. The rates of unbalanced sperm were 12.0 % in Robertsonian and 55.1 % in reciprocal translocation carriers with no difference between normospermic patients and those showing altered semen parameters. Significantly increased frequencies of spermatozoa showing defects in chromatin integrity and condensation, aneuploidy for chromosomes not involved in a translocation and diploidy were detected in translocation carriers with abnormal semen parameters. Normospermic reciprocal translocation carriers showed an increase in chromosome 13 disomy compared to the control group. There was no relationship between gametic and somatic aneuploidy in 12 translocation carriers studied by FISH on sperm and lymphocytes. The frequency of motile sperm was negatively correlated with the frequency of sperm showing disomy, diploidy and defective chromatin condensation. CONCLUSIONS: Abnormal semen parameters can serve as indicators of an additional risk of forming spermatozoa with defective chromatin and aneuploidy in translocation carriers.

Sperm meiotic segregation, aneuploidy and high risk of delivering an affected offspring in carriers of non-Robertsonian translocation t(13;15).

PURPOSE: To determine the percentage of unbalanced spermatozoa and an interchromosomal effect in two carriers of balanced translocations t(13;15)(q32;q26) and t(13;15)(q32;p11.2). METHODS: Sperm nuclei analysis by fluorescent in situ hybridization for detection of percentage of unbalanced spermatozoa and sperm with disomy of chromosomes X, Y, 8, 18, 21 and diploidy. RESULTS: The incidence of unbalanced spermatozoa was 50.5 % and 44.6 % in patient 1 (P1) and patient 2 (P2), respectively. Partial disomy of chromosome 13 was detected in 13.4 % and 21.3 % of sperm in P1 and P2, respectively. The unbalanced karyotype der(15)t(13;15) was found previously in a son of P1 and in two adult relatives, and prenatally in the family of P2. This demonstrates a high risk of delivering an affected offspring. Significantly increased frequencies of chromosomes 8, 18, X and XY disomy and diploidy were observed in P2, which might either indicate an interchromosomal effect or be related to his asthenoteratozoospermia. CONCLUSIONS: Since the proportions of unbalanced spermatozoa and the risk of delivering an affected offspring are high, prenatal or preimplantation genetic diagnosis is recommended for such patients.

Sperm and embryo analysis of similar t(7;10) translocations transmitted in two families.

OBJECTIVE: To compare the sperm meiotic segregation profiles in two men from families with similar t(7;10) translocations and determine the frequency of unbalanced sperm and preimplantation embryos in one couple. DESIGN: Analysis of sperm nuclei and blastomeres by fluorescence in situ hybridization (FISH). SETTING: Research institute. PATIENT(S): Carriers of balanced translocations t(7;10)(q34;q24) and t(7;10)(q36;q24.3). INTERVENTION(S): Multicolor FISH using probes for chromosomes 7, 10, 8, 18, 21, X, and Y on sperm and preimplantation genetic diagnosis (PGD) of blastomeres. MAIN OUTCOME MEASURE(S): Frequencies of meiotic segregation products in sperm and blastomeres and sperm aneuploidy of chromosomes 8, 18, 21, X, and Y. RESULT(S): Similar meiotic segregation patterns, with preferential alternate segregation (50.6% in patient P1, 48.1% in P2) followed by adjacent 1, adjacent 2 and 3:1 segregations, were observed in the sperm of the two carriers. An interchromosomal effect on the sex chromosomes was found when compared with disomy frequencies reported in control donors. The results of preimplantation genetic diagnosis in the first couple are roughly consistent with the sperm analysis results. CONCLUSION(S): Carriers of similar translocations show similar segregation profiles. The in vitro fertilization method accompanied by preimplantation genetic diagnosis increases the chance of translocation carriers fathering a healthy child.

der(4)t(Y;4): Three-generation transmission and sperm meiotic segregation analysis.

We present a family where five members (three males and two females) are carriers of der(4)t(Y;4)(q11.23;p16.3). The adult carriers are phenotypicaly normal and fertile; the boy shows macrocephaly, psychomotor retardation, and atypical autism. The FISH on cultured lymphocytes confirmed that the redundant Yq heterochromatin was attached to the 4p-subtelomeric region maintained on the der(4). Sperm FISH analysis performed in a normospermic der(4) carrier showed a significant distortion of the expected 1:1 ratio of the X- and Y-bearing spermatozoa in favor of the X chromosome and significant lack of Y,der(4)spermatozoa. The overall lack of Y spermatozoa was not balanced even by a relative excess of Y,4 sperm. The analysis of X, Y, 7, 8, 18, and 21 sperm disomy and diploidy did not indicate any interchromosomal effect. The chromosome 4 disomy was significantly increased but still very low to be of considerable reproductive significance. The neurodevelomental phenotype of the boy was probably caused by a gene mutation. The coincidental occurrence of such chromosomal aberration and boy's phenotype might lead to misinterpretation of the causal relationship between these findings. It is necessary to consider the results of chromosomal analysis and clinical records of relatives for provide genetic counseling in such families.

Selectivity of hyaluronic acid binding for spermatozoa with normal Tygerberg strict morphology.

During spermiogenesis, a plasma membrane remodelling step facilitates formation of sperm zona pellucida and hyaluronic acid (HA) binding sites. Enrichment of Tygerberg normal spermatozoa in HA-bound versus semen sperm fractions was postulated. Semen was placed on the uncoated A side and HA-coated B side of a semen chamber. After 15 min, the HA binding score (proportion of HA-bound motile spermatozoa) was assessed on the B side, and unbound spermatozoa were removed by gentle rinsing. Following Diff-Quick staining, sperm morphology of A and B sides was evaluated by three blinded investigators at Yale and Tygerberg. The proportion of Tygerberg normal spermatozoa was higher in HA-bound versus semen spermatozoa (n = 63 subjects) with a 3.04-fold improvement (95% confidence limits: 1.9-4.7) in 37 teratozoospermic men, comparable with a 4.2-fold enrichment in zona pellucida-bound spermatozoa reported earlier by the Tygerberg group. The morphology scores of three investigators were different but related, indicating that the variations reflect individual-to-individual differences in the perception of shape normality. The selection power of HA and zona pellucida for normal spermatozoa are similar. The sperm biomarkers of creatine phosphokinase (reflecting retained cytoplasm in arrested maturity spermatozoa) and chaperone protein HspA2 (heat shock protein) were proportional with sperm HA binding. As HA binding reflects sperm maturity and function, the combination of Tygerberg morphology and HA binding is likely to improve male infertility management.