Sperm DNA methylation changes after short-term nut supplementation in healthy men consuming a Western-style diet.

BACKGROUND: Many environmental and lifestyle factors have been implicated in the decline of sperm quality, with diet being one of the most plausible factors identified in recent years. Moreover, several studies have reported a close association between the alteration of specific sperm DNA methylation signatures and semen quality. OBJECTIVES: To evaluate the effect of tree nut consumption on sperm DNA methylation patterns in healthy individuals reporting eating a Western-style diet. MATERIAL AND METHODS: This is a post hoc analysis conducted in a subset of participants (healthy, non-smoking, and young) from the FERTINUTS 14-wk randomized-controlled, parallel trial, recruited between December 2015 and February 2017. The participants included in the current study (n = 72) were randomly selected in a proportion 2:1 from the original FERTINUTS trial between the 98 participants that completed the entire dietary intervention (nut group, n = 48; control group, n = 24). Sperm DNA methylation patterns were examined at baseline and after 14 weeks in 48 individuals consuming 60 g/d of mixed nuts (nut group) and in 24 individuals following the usual Western-style diet avoiding consumption of nuts (control group). RESULTS: Over the course of the trial, no significant changes in global methylation were observed between groups. However, in the nut group, we identified 36 genomic regions that were significantly differentially methylated between the baseline and the end of the trial and 97.2% of the regions displayed hypermethylation. We identified no such change in the control group over the same period of time. We also utilized the recently developed germ line age calculator to determine if nut consumption resulted in alterations to the epigenetic age of cells and no significant differences were found. DISCUSSION AND CONCLUSION: Adding nuts to a regular Western-style diet subtly impacts sperm DNA methylation in specific regions, demonstrating that there are some sperm epigenome regions that could respond to diet.

Genetic dissection of spermatogenic arrest through exome analysis: clinical implications for the management of azoospermic men.

PURPOSE: Azoospermia affects 1% of men and it can be the consequence of spermatogenic maturation arrest (MA). Although the etiology of MA is likely to be of genetic origin, only 13 genes have been reported as recurrent potential causes of MA. METHODS: Exome sequencing in 147 selected MA patients (discovery cohort and two validation cohorts). RESULTS: We found strong evidence for five novel genes likely responsible for MA (ADAD2, TERB1, SHOC1, MSH4, and RAD21L1), for which mouse knockout (KO) models are concordant with the human phenotype. Four of them were validated in the two independent MA cohorts. In addition, nine patients carried pathogenic variants in seven previously reported genes-TEX14, DMRT1, TEX11, SYCE1, MEIOB, MEI1, and STAG3-allowing to upgrade the clinical significance of these genes for diagnostic purposes. Our meiotic studies provide novel insight into the functional consequences of the variants, supporting their pathogenic role. CONCLUSION: Our findings contribute substantially to the development of a pre-testicular sperm extraction (TESE) prognostic gene panel. If properly validated, the genetic diagnosis of complete MA prior to surgical interventions is clinically relevant. Wider implications include the understanding of potential genetic links between nonobstructive azoospermia (NOA) and cancer predisposition, and between NOA and premature ovarian failure.

NRF2 loss recapitulates heritable impacts of paternal cigarette smoke exposure.

Paternal cigarette smoke (CS) exposure is associated with increased risk of behavioral disorders and cancer in offspring, but the mechanism has not been identified. Here we use mouse models to investigate mechanisms and impacts of paternal CS exposure. We demonstrate that CS exposure induces sperm DNAme changes that are partially corrected within 28 days of removal from CS exposure. Additionally, paternal smoking is associated with changes in prefrontal cortex DNAme and gene expression patterns in offspring. Remarkably, the epigenetic and transcriptional effects of CS exposure that we observed in wild type mice are partially recapitulated in Nrf2-/- mice and their offspring, independent of smoking status. Nrf2 is a central regulator of antioxidant gene transcription, and mice lacking Nrf2 consequently display elevated oxidative stress, suggesting that oxidative stress may underlie CS-induced heritable epigenetic changes. Importantly, paternal sperm DNAme changes do not overlap with DNAme changes measured in offspring prefrontal cortex, indicating that the observed DNAme changes in sperm are not directly inherited. Additionally, the changes in sperm DNAme associated with CS exposure were not observed in sperm of unexposed offspring, suggesting the effects are likely not maintained across multiple generations.

Microfluidic System for Rapid Isolation of Sperm From Microdissection TESE Specimens.

OBJECTIVES: To demonstrate a novel prototype microfluidic system for rapid isolation of sperm from real and simulated microdissection testicular sperm extraction samples. METHODS: The novel microfluidic system was tested using minced testicular biopsies from patients with nonobstructive azoospermia. The samples were split into 2 portions, conventional processing vs microfluidic. The embryologists were blinded to the processing protocol and searched the specimens for sperm after processing. We recorded the number of sperm found and the time to sperm identification and compared the sperm retrieval rates. RESULTS: When compared to conventional methods, samples processed through the microfluidic system were cleaner (decreased somatic cells/debris), with the average number of sperm identified per minute improving from 1.52 sperm per minute for the control and 13.5 sperm per minute with the device yielding an 8.88 fold improvement in the sperm found per minute for the device as compared to the control. Preliminary viability and morphology tests show a minimal impact on sperm processed through the microfluidic system. CONCLUSION: The presented microfluidic system can facilitate rapid and efficient isolation of sperm from microdissection testicular sperm extraction samples. A prospective clinical trial to verify these results is needed to confirm this preliminary data.

Rare mutations in the complement regulatory gene CSMD1 are associated with male and female infertility.

Infertility in men and women is a complex genetic trait with shared biological bases between the sexes. Here, we perform a series of rare variant analyses across 73,185 women and men to identify genes that contribute to primary gonadal dysfunction. We report CSMD1, a complement regulatory protein on chromosome 8p23, as a strong candidate locus in both sexes. We show that CSMD1 is enriched at the germ-cell/somatic-cell interface in both male and female gonads. Csmd1-knockout males show increased rates of infertility with significantly increased complement C3 protein deposition in the testes, accompanied by severe histological degeneration. Knockout females show significant reduction in ovarian quality and breeding success, as well as mammary branching impairment. Double knockout of Csmd1 and C3 causes non-additive reduction in breeding success, suggesting that CSMD1 and the complement pathway play an important role in the normal postnatal development of the gonads in both sexes.

Paternal germ line aging: DNA methylation age prediction from human sperm.

BACKGROUND: The relationship between aging and epigenetic profiles has been highlighted in many recent studies. Models using somatic cell methylomes to predict age have been successfully constructed. However, gamete aging is quite distinct and as such age prediction using sperm methylomes is ineffective with current techniques. RESULTS: We have produced a model that utilizes human sperm DNA methylation signatures to predict chronological age by utilizing methylation array data from a total of 329 samples. The dataset used for model construction includes infertile patients, sperm donors, and individuals from the general population. Our model is capable predicting age with an R2 of 0.89, a mean absolute error (MAE) of 2.04 years, and a mean absolute percent error (MAPE) of 6.28% in our data set. We additionally investigated the reproducibility of prediction with our model in an independent cohort where 6 technical replicates of 10 individual samples were tested on different arrays. We found very similar age prediction accuracy (MAE = 2.37 years; MAPE = 7.05%) with a high degree of precision between replicates (standard deviation of only 0.877 years). Additionally, we found that smokers trended toward increased age profiles when compared to 'never smokers' though this pattern was only striking in a portion of the samples screened. CONCLUSIONS: The predictive model described herein was built to offer researchers the ability to assess "germ line age" by accessing sperm DNA methylation signatures at genomic regions affected by age. Our data suggest that this model can predict an individual's chronological age with a high degree of accuracy regardless of fertility status and with a high degree of repeatability. Additionally, our data suggest that the aging process in sperm may be impacted by environmental factors, though this effect appears to be quite subtle and future work is needed to establish this relationship.

Childhood Cancer Risk in the Siblings and Cousins of Men with Poor Semen Quality.

PURPOSE: Poor semen quality is associated with reduced somatic health and increased cancer risk. Infertility and cancer are increasingly being linked by epidemiologists and basic scientists. We sought to identify semen parameters associated with an increased childhood cancer risk in the family members of subfertile men. MATERIALS AND METHODS: We performed a retrospective cohort study in men from the SHARE (Subfertility Heath and Assisted Reproduction) study who underwent semen analysis between 1994 and 2011. We used fertile population controls from the Utah Population Data Base. Our primary outcome was the risk of any childhood (18 years or younger) cancer in the siblings and cousins of men who underwent semen analysis compared to fertile, age matched controls. Cox proportional hazard regression models were used to test the association between semen quality and childhood cancer incidence. RESULTS: We selected 10,511 men with complete semen analysis and an equal number of fertile controls. These men had a total of 63,891 siblings and 327,753 cousins. A total of 170 and 958 childhood cancers were identified in siblings and cousins, respectively. The 3 most common cancers diagnosed in siblings were acute lymphoblastic leukemia in 37, brain cancer in 35 and Hodgkin lymphoma in 15. Oligozoospermia was associated with a twofold increased risk of any childhood cancer and a threefold increased risk of acute lymphoblastic leukemia in the siblings of subfertile men compared to fertile controls (HR 2.09, 95% CI 1.18-3.69 vs HR 3.07, 95% CI 1.11-8.46). CONCLUSIONS: Siblings of men with oligozoospermia are at increased risk for any-site cancer and acute lymphoblastic leukemia. This suggests a shared genetic/epigenetic insult or an environmental exposure that merits further investigation.

Risk of childhood mortality in family members of men with poor semen quality.

STUDY QUESTION: What is the familial childhood mortality in first-degree (FDR) and second-degree relatives (SDR) of patients undergoing semen analysis (SA)? SUMMARY ANSWER: The relationship between infertility and congenital malformations (CM) in offspring is complex, with an increased risk of death due to CM in FDR, but not SDR, of men with lower semen parameters. WHAT IS KNOWN ALREADY: Semen quality is an established predictor of men's somatic health. We can gain a better understanding of possible genetic or environmental determinants of the infertility phenotype by exploring familial aggregation of childhood mortality in relatives of men with poor semen quality. STUDY DESIGN, SIZE, DURATION: Retrospective cohort study from the Subfertility, Health and Assisted Reproduction study (cohort compiled 1996-2011) linked with patient/familial information from the Utah Population Database (UPDB). Index cases included a clinic-referred sample of 12 889 men who underwent SA and had adequate familial and follow-up data in the UPDB. Parameters of semen quality included: semen concentration, sperm count, motility, total motile count, sperm head morphology, sperm tail morphology and vitality. PARTICIPANTS/MATERIALS, SETTING, METHODS: SA data were collected from two tertiary medical center andrology laboratories that have captured ~90% of all SA performed in Utah since 2004. Age- and sex-matched fertile controls were selected to create the comparison group for determining risk of childhood death (to age 20 years) in family members. A total of 79 750 siblings and 160 016 aunts/uncles were used to investigate the familial aggregation of childhood mortality. The main outcome was childhood mortality in FDR and SDR of men with SA and their matched controls. All-cause and cause-specific Cox proportional hazard models were used to test the association between semen quality and childhood mortality in family members. Cause-specific models were considered for cancer and CM. MAIN RESULTS AND THE ROLE OF CHANCE: In the cohort of men with SA, there were 406 (1.0%) deaths in FDR and 772 (1.1%) deaths in SDR due to any cause. There was no significant difference in the risk of all-cause childhood mortality between the relatives of men with SA and the fertile control group [hazard ratio (HR)Female = 1.08, 95% CI = 0.88, 1.32; HRMale = 0.88, 95% CI = 0.75, 1.04]. We found no association between semen quality and risk for childhood cancer mortality in FDR or SDR (HRFDR = 0.98, 95% CI = 0.62, 1.54; HRSDR = 1.12, 95% CI = 0.83, 1.50). The FDR of men with SA and fertile controls were followed on average for 19.71 and 19.73 years, respectively. During this period of follow-up, FDR of men with SA had an unadjusted 40% relative risk of increased CM-related death. After stratifying by semen parameters and adjusting for birth year, we found FDR of men with worse semen quality, and notably azoospermic men (HR = 2.69, 95% CI = 1.24,5.84), were at higher risk of CM-related death. LIMITATIONS REASONS FOR CAUTION: A large proportion of men with SA in the study had normal semen parameters. It is important to note that these men themselves may not be subfertile, but they were subfertile at the couple level (i.e. the female partner may be infertile). In addition, care is needed when interpreting our results, as we do not have semen measures on our sample of fertile men. Second, we were unable to include potential confounders such as medical comorbidities, smoking status, or environmental exposures. Third, men with SA were seen at the University of Utah or Intermountain Health Care clinics for a fertility evaluation thereby suggesting a more select population. Fourth, we chose to categorize morphology into equally distributed quartiles as a response to the fact that the World Health Organization threshold for normal motility changed multiple times during our study period. Lastly, we do not know the proportion of female partners with diagnosed infertility. We chose not to subcategorize each infertile male by infertile diagnosis because our goal was to understand how semen parameters influenced familial childhood mortality. WIDER IMPLICATIONS OF THE FINDINGS: We are not the first study to show a relationship between fertility and CMs. Children conceived through ART may be at higher risk of birth defects, however it is not known if the relationship is causal or if there is some underlying factor linking infertility and birth outcomes. This study provides further evidence that the increased risk of congenital birth defects may not be due to the ART, but rather genetic or environmental factors that link the two outcomes. We encourage further research in order to confirm a relationship between semen quality and increased risk for CM. STUDY FUNDING/COMPETING INTERESTS: This work was supported by the National Institutes of Health - National Institute of Aging [Grant numbers 1R21AG036938-01, 2R01 AG022095 and 1K12HD085852-01]. Authors have no competing interests to disclose. TRIAL REGISTRATION NUMBER: Not applicable.

Cancer risk in first- and second-degree relatives of men with poor semen quality.

OBJECTIVE: To further characterize the association of male infertility with health risks by evaluating semen quality and cancer risk in family members. DESIGN: Retrospective, cohort study. SETTING: Not applicable. PATIENT(S): A total of 12,889 men undergoing SA and 12,889 fertile control subjects that had first-degree relative (FDR) data (n = 130,689) and 8,032 men with SA and 8,032 fertile control subjects with complete second-degree relative (SDR) data (n = 247,204) were identified through the UPDB. An equal number of fertile population control subjects were matched. INTERVENTIONS: None. MAIN OUTCOME MEASURE(S): Adult all-site, testicular, thyroid, breast, prostate, melanoma, bladder, ovarian, and kidney cancer diagnoses in FDRs and SDRs. RESULT(S): The FDRs of men with SA had a 52% increased risk of testicular cancer compared with the FDRs of fertile population control subjects. There was no significant difference in testicular cancer risk for the SDRs based on any of the semen parameters. The FDRs and SDRs of azoospermic men had a significantly increased risk of thyroid cancer compared with fertile population control subjects. CONCLUSION(S): These data suggest a link between male infertility and selected cancer risk in relatives. This highlights the possibilities of shared biologic mechanisms between the two diseases, exposure to environmental factors, and an increased level of genetic and/or epigenetic burden in subfertile men and their relatives that may be associated with risk of cancer.

Subfertility increases risk of testicular cancer: evidence from population-based semen samples.

OBJECTIVE: To further understand the association between semen quality and cancer risk by means of well defined semen parameters. DESIGN: Retrospective cohort study. SETTING: Not applicable. PATIENT(S): A total of 20,433 men who underwent semen analysis (SA) and a sample of 20,433 fertile control subjects matched by age and birth year. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Risk of all cancers as well as site-specific results for prostate cancer, testicular cancer, and melanoma. RESULT(S): Compared with fertile men, men with SA had an increased risk of testicular cancer (hazard rate [HR] 3.3). When the characterization of infertility was refined using individual semen parameters, we found that oligozoospermic men had an increased risk of cancer compared with fertile control subjects. This association was particularly strong for testicular cancer, with increased risk in men with oligozoospermia based on concentration (HR 11.9) and on sperm count (HR 10.3). Men in the in the lowest quartile of motility (HR 4.1), viability (HR 6.6), morphology (HR 4.2), or total motile count (HR 6.9) had higher risk of testicular cancer compared with fertile men. Men with sperm concentration and count in the 90th percentiles of the distribution (≥178 and ≥579 × 10(6)/mL, respectively), as well as total motile count, had an increased risk of melanoma (HRs 2.1, 2.7, and 2.0, respectively). We found no differences in cancer risk between azoospermic and fertile men. CONCLUSION(S): Men with SA had an increased risk of testicular cancer which varied by semen quality. Unlike earlier work, we did not find an association between azoospermia and increased cancer risk.

Age-associated sperm DNA methylation alterations: possible implications in offspring disease susceptibility.

Recent evidence demonstrates a role for paternal aging on offspring disease susceptibility. It is well established that various neuropsychiatric disorders (schizophrenia, autism, etc.), trinucleotide expansion associated diseases (myotonic dystrophy, Huntington's, etc.) and even some forms of cancer have increased incidence in the offspring of older fathers. Despite strong epidemiological evidence that these alterations are more common in offspring sired by older fathers, in most cases the mechanisms that drive these processes are unclear. However, it is commonly believed that epigenetics, and specifically DNA methylation alterations, likely play a role. In this study we have investigated the impact of aging on DNA methylation in mature human sperm. Using a methylation array approach we evaluated changes to sperm DNA methylation patterns in 17 fertile donors by comparing the sperm methylome of 2 samples collected from each individual 9-19 years apart. With this design we have identified 139 regions that are significantly and consistently hypomethylated with age and 8 regions that are significantly hypermethylated with age. A representative subset of these alterations have been confirmed in an independent cohort. A total of 117 genes are associated with these regions of methylation alterations (promoter or gene body). Intriguingly, a portion of the age-related changes in sperm DNA methylation are located at genes previously associated with schizophrenia and bipolar disorder. While our data does not establish a causative relationship, it does raise the possibility that the age-associated methylation of the candidate genes that we observe in sperm might contribute to the increased incidence of neuropsychiatric and other disorders in the offspring of older males. However, further study is required to determine whether, and to what extent, a causative relationship exists.

The sperm epigenome: implications for the embryo.

Recent advances, including the human genome project and numerous studies of cancer and other diseases, have shown that the genetic code is not simply limited to the sequence of the four bases of DNA but also includes epigenetic programming, heritable changes that affect gene expression [Riggs A, Martinssen R, Russo V (2007) Introduction. In: Riggs A, Martinssen R, Russo V (eds) Epigenetics mechanisms of gene regulation. Cold Spring Harbor Press, New York]. The science of epigenetics is important in understanding many diseases and biological processes, including in identifying the causes of disease and better understanding the mechanisms by which the environment can affect gene expression [Carrell Fertil Steril 97 (2):267-274, 2012]. This chapter will focus on the epigenome of sperm and particularly highlight the potential role of the sperm epigenome in embryogenesis.The sperm epigenome is unique and highly specialized because of the unique nature and function of sperm and because of the diverse requirements for successful fertilization. Due to the need for motility, sperm chromatin must be compacted and highly organized. During spermiogenesis the chromatin is packaged tightly into the sperm head by the replacement of most histones with protamines. This allows for protection of the DNA from the hostile environment in the female reproductive tract. Remaining histones can have chemical modifications to the tails of the protein that either facilitate or repress gene transcription. Sperm, like embryonic stem cells, have a unique pattern of histone modifications that includes both activating and silencing marks in the promoters of genes associated with development. These bivalent marks, along with DNA hypomethylation, comprise a unique state in which the key genes are "poised" for possible activation in embryogenesis. Sperm epigenetic abnormalities have been linked with multiple diseases including male factor infertility and poor embryogenesis.

Analysis of gene-specific and genome-wide sperm DNA methylation.

Epigenetic modifications on the DNA sequence (DNA methylation) or on chromatin-associated proteins (i.e., histones) comprise the "cellular epigenome"; together these modifications play an important role in the regulation of gene expression. Unlike the genome, the epigenome is highly variable between cells and is dynamic and plastic in response to cellular stress and environmental cues. The role of the epigenome, specifically, the methylome has been increasingly highlighted and has been implicated in many cellular and developmental processes such as embryonic reprogramming, cellular differentiation, imprinting, X chromosome inactivation, genomic stability, and complex diseases such as cancer. Over the past decade several methods have been developed and applied to characterize DNA methylation at gene-specific loci (using either traditional bisulfite sequencing or pyrosequencing) or its genome-wide distribution (microarray analysis following methylated DNA immunoprecipitation (MeDIP-chip), analysis by sequencing (MeDIP-seq), reduced representation bisulfite sequencing (RRBS), or shotgun bisulfite sequencing). This chapter reviews traditional bisulfite sequencing and shotgun bisulfite sequencing approaches, with a greater emphasis on shotgun bisulfite sequencing methods and data analysis.

Association of 25-hydroxy-vitamin D levels with semen and hormonal parameters.

Vitamin D levels have been linked to various health outcomes including reproductive disorders. The purpose of this study was to explore the association between serum vitamin D level (25-hydroxy-vitamin D, or 25OHD) and semen and hormonal parameters. This is a cross-sectional study that included 170 healthy men recruited for the study of spermatogenesis from the general population. Men completed general and reproductive health questionnaires, and donated blood and semen samples. The main measures were hormonal (total and free testosterone, sex hormone-binding globulin, estradiol, follicle-stimulating hormone and luteinizing hormone) and semen parameters, adjusted (n=147) for age, body mass index (BMI), season, alcohol intake and smoking, in relation to categories of vitamin D levels, determined a priori. The mean age of the study population was 29.0±8.5 years and mean BMI was 24.3±3.2 kg m(-2). The mean 25OHD was 34.1±15.06 ng ml(-1). BMI showed a negative association with 25OHD. Sperm concentration, sperm progressive motility, sperm morphology, and total progressively motile sperm count were lower in men with '25OHD≥50 ng ml(-1)' when compared to men with '20 ng ml(-1)≤25OHD<50 ng ml(-1)'. Total sperm count and total progressive motile sperm count were lower in men with '25OHD<20 ng ml(-1)' when compared to men with '20 ng ml(-1)≤25OHD<50 ng ml(-1)'. The adjusted means of various hormonal parameters did not show statistical difference in the different categories of 25OHD. In conclusion, serum vitamin D levels at high and low levels can be negatively associated with semen parameters.

Emerging evidence for the role of genomic instability in male factor infertility.

Male infertility is a common and complex pathology affecting about 7% of men of reproductive age. Given its complexity, the underlying etiology for male infertility is often unknown. A growing amount of evidence suggests genomic instability may be an important factor in some cases of male factor infertility. While some specific manifestations of genomic instability, such as increased sperm aneuploidy rates and increased somatic translocations and inversions in infertile men, are well established, other facets of genomic instability associated with male infertility have not been thoroughly investigated. A limited body of recent work has identified a potential association between microsatellite instability and spermatogenic failure. In addition, mutations in mismatch repair and tumor suppressor genes, which could potentially lead to genomic instability, have been identified in some infertile men and animal models. In addition, results of two epidemiologic studies suggest spermatogenic defects might be just one aspect of a more systemic problem, possibly due to increased genomic instability. In this review we discuss well-established links between genomic instability and male infertility, as well as some of the emerging but less established data to support this relationship. We also propose some important areas of future research toward a more complete understanding of the underlying mechanisms for male infertility.

Association of aromatase (TTTAn) repeat polymorphism length and the relationship between obesity and decreased sperm concentration.

BACKGROUND: Obesity in men is associated with low sperm count, however, this finding is inconsistent. Here, we describe length of the short tandem repeat aromatase (CYP19A1) polymorphism and its relationship to increased weight and sperm count. METHODS: A cohort of 215 men was recruited from the community and BMI, hormone levels and sperm parameters were determined at enrollment. Men (196) were genotyped for length of the tetranucleotide TTTA repeats polymorphism (TTTA(n)), defined as short (S ≤ 7 repeats) or long (L > 7 repeats). Genotypes were categorized using allele combinations as 'low repeats' = S-S, or 'high repeats' = S-L/L-L. Weight and sperm parameters were examined in relation to size of TTTA(n) repeat. RESULTS: Mean (±SD) age was 29.8 ± 8.6 years and mean BMI was 25.6 ± 4.6 kg/m(2). Men with high repeats had higher estradiol (E(2)) levels (98.0 ± 33.36 pmol/l) than men with low repeats (85.9 ± 26.61 pmol/l; P= 0.026). Lower FSH levels tended to be present in men with high repeats versus men with low repeats (P= 0.052). After stratification by genotype, a negative correlation between BMI and sperm count (Pearson's coefficient = 0.406) was seen only among men with high repeats (P= 0.019). Only men with high repeats exhibited increased E(2) with increased weight. A decrease in testosterone: E(2) ratio with increasing BMI was more pronounced in men with high versus low, repeats (R(2) = 0.436 versus 0.281). CONCLUSIONS: Higher TTTA repeat numbers (>7 repeats) in the aromatase gene are associated with a negative relationship between obesity and sperm count. The effect of obesity on E(2) and sperm count appears to be absent in men with low (≤7) repeats.

Disease progression and solid tumor survival: a transcriptome decoherence model.

Networks of genes are typically generated from expression changes observed between control and test conditions. Nevertheless, within a single control state many genes show expression variance across biological replicates. These transcripts, typically termed unstable, are usually excluded from analyses because their behavior cannot be reconciled with biological constraints. Grouped as pairs of covariant genes they can however show a consistent response to the progression of a disease. We present a model of coherence arising from sets of covariant genes that was developed in-vitro then tested against a range of solid tumors. DGPMs, Decoherence Gene Pair Models, showed changes in network topology reflective of the metastatic transition. Across a range of solid tumor studies the model generalizes to reveal a richly connected topology of networks in healthy tissues that becomes sparser as the disease progresses reaching a minimum size in the advanced tumors with minim survivability.

Alterations in sperm DNA methylation patterns at imprinted loci in two classes of infertility.

OBJECTIVE: To evaluate the associations between proper protamine incorporation and DNA methylation at imprinted loci. DESIGN: Experimental research study. SETTING: Research laboratory. PATIENT(S): Three populations were tested-abnormal protamine patients, oligozoospermic patients, and fertile donors. INTERVENTION(S): The CpG methylation patterns were examined at seven imprinted loci sequenced: LIT1, MEST, SNRPN, PLAGL1, PEG3, H19, and IGF2. MAIN OUTCOME MEASURE(S): The DNA methylation patterns were analyzed using bisulfite sequencing. The percentage of methylation was compared between fertile and infertile patients displaying abnormal protamination. RESULT(S): At six of the seven imprinted genes, the overall DNA methylation patterns at their respective differentially methylated regions were significantly altered in both infertile patient populations. When comparing the severity of methylation alterations among infertile patients, the oligozoospermic patients were significantly affected at mesoderm-specific transcript (MEST), whereas abnormal protamine patients were affected at KCNQ1, overlapping transcript 1 (LIT1), and at small nuclear ribonucleoprotein polypeptide N (SNRPN). CONCLUSION(S): Patients with male factor infertility had significantly increased methylation alteration at six of seven imprinted loci tested, with differences in significance observed between oligozoospermic and abnormal protamine patients. This could suggest that risk of transmission of epigenetic alterations may be different with diagnoses. However, this study does not provide a causal link for epigenetic inheritance of imprinting diseases, but does show significant association between male factor infertility and alterations in sperm DNA methylation at imprinted loci.

An aromatase polymorphism modulates the relationship between weight and estradiol levels in obese men.

OBJECTIVE: To describe the influence of the TTTA aromatase polymorphism (TTTAn) on the relation between obesity and plasma estradiol (E(2)) in obese men. DESIGN: A 2-year cohort study. SETTING: Clinical research center. PATIENT(S): Severely obese men (31 who had had gastric bypass surgery and 118 controls). INTERVENTION(S): Men were genotyped for the TTTAn CYP19A1 polymorphism. Anthropomorphic measures, plasma E(2), and other hormonal levels were determined at baseline and 2-year follow-up. MAIN OUTCOMES MEASURE(S): Relationships between weight and changes in weight and plasma E(2) were examined in relation to the TTTAn polymorphism. RESULT(S): The mean age was 46.5 ± 10.82 years, and mean body mass index was 47.1 ± 8.46 kg/m(2). The most common repeats were 7 and 11. TTTAn number did not correlate with plasma E(2) in the univariate analysis. When patients were stratified per weight group, the correlation between plasma E(2) and weight was seen only among men with a higher TTTA repeat at baseline and 2 years. Similarly, only men with higher TTTA exhibited reduced E(2) levels after weight loss. CONCLUSION(S): A higher TTTA repeat is associated with a strengthened relationship between obesity and E(2). The well-established effect of increased weight on plasma E(2) appears to be absent in men with low TTTA numbers.