Impact of waterpipe and tobacco cigarette smoking on global DNA methylation and nuclear proteins genes transcription in spermatozoa: a comparative investigation

BACKGROUND

Waterpipe smoking is harmful and dangerous, and it is a growing threat to public health.

OBJECTIVES

This study was performed to evaluate the influence of waterpipe smoking on global DNA methylation, DNA fragmentation, and protamine deficiency in spermatozoa compared to cigarette heavy smokers and nonsmokers, and to determine whether the transcription levels of spermatozoa nuclear proteins genes 'PRM1, PRM2, and H2BFWT' in waterpipe smokers are different compared to cigarette heavy smokers and nonsmokers.

METHODS

A total of 900 semen samples were collected from males with a mean age of 32.5 ± 6.3 years (300 waterpipe smokers, 300 cigarette heavy smokers, and 300 nonsmokers). The nucleic acids were isolated from purified spermatozoa, and then the global DNA methylation and transcription levels of the PRM1, PRM2, and H2BFWT genes were assessed using ELISA and qPCR, respectively.

RESULTS

A significant increase was found in the level of global DNA methylation (8.6 ± 0.6 ng/μl vs. 7.1 ± 0.6 ng/μl and 4.7 ± 0.6 ng/μl, p < 0.001), protamine deficiency (72.8 ± 15.3 vs. 51.7 ± 19.2 and 15.3 ± 5.9%, p < 0.001), and DNA fragmentation (73.4 ± 13.4 vs. 50.5 ± 18.9 and 9.3 ± 4.3%, p < 0.001) in waterpipe smokers compared to cigarette heavy smokers and nonsmokers. A significant increase was shown in the transcription levels of PRM1, PRM2, and H2BFWT genes in waterpipe smokers compared to cigarette heavy smokers and nonsmokers (p < 0.001). A down-regulation was found in the transcription level of these genes in different smoker groups compared to nonsmokers (<0.001).

CONCLUSION

This study suggests that waterpipe smoking is more harmful than cigarette smoking on semen parameters, global DNA methylation, and transcription of nuclear protein genes.

Investigation of the Predictive Factors of Diminished Ovarian Reserve in Women Aged Less Than 40 Years and Undergoing ICSI Cycle

Diminished ovarian reserve (DOR) is one of the primary causes of poor ICSI outcomes. Therefore, this study was performed to speculate which of the following parameters: AMH, AFC, and women's age can be used as a predictor factor of the DOR in women aged < 40 years. This prospective study enrolled 500 women suffering from idiopathic infertility problems and who underwent GnRH antagonist multiple-dose stimulation protocol. The women were divided into two groups: normal fertility (FSH ≤ 10 mIU/mL, n = 300) and DOR (FSH > 10 mIU/mL, n = 200). At the time of the study, the average of women age was 29.3 ± 5.7 years. A significant reduction was found in AMH level, AFC, number of mature, immature oocytes, fertilized oocytes, embryos transferred, and β-hCG level in the DOR group compared to the normal fertility group (P < 0.001). Conversely, a significant increase was shown in the age of the DOR group compared to the normal fertility group (30.8 ± 5.8 vs. 28.2 ± 5.4, respectively; P < 0.001). A significant negative association was found between the AFC, the number of mature oocytes, fertilized oocytes, embryos transferred, and the basal level of FSH in the DOR group (P < 0.01). The receiver operating characteristics (ROC) demonstrated that AMH level and AFC had the highest accuracy, followed by age in the prediction of DOR (P < 0.001) with a cut-off value of ≤ 1.2 ng/mL, ≤ 4.5, and > 29.5 years, respectively. This study exhibited that the levels of AMH and AFC are the best biomarkers, followed by age for the prediction of DOR in women < 40 years old. Furthermore, AMH is the only independent factor that is significantly related to DOR in women.

Effect of hubble-bubble smoking on global DNA methylation and transcription levels of protamine and histone genes in human spermatozoa

This study was conducted to assess the impact of hubble-bubble smoking on global DNA methylation, DNA fragmentation; protamine deficiency of spermatozoa, and to determine whether the transcription levels of the protamine and histone genes are different in hubble-bubble smokers compared to nonsmokers. Five hundred semen samples were collected from males with an average age of 32.2 ± 6.1 years (300 hubble-bubble smokers "60%" and 200 nonsmokers "40%"). The nucleic acid was isolated from purified sperm, then ELISA and qPCR were used to evaluate the global DNA methylation and transcription level of protamine and histone, respectively. A significant elevation in global DNA methylation, protamine deficiency, and DNA fragmentation was found in hubble-bubble smokers compared to nonsmokers (P < 0.0001). A significant decline was shown in transcription levels of protamine and histone genes in hubble-bubble compared to nonsmokers (P < 0.0001). Additionally, a down-regulation in the transcription levels of protamine and histone was revealed in hubble-bubble compared to nonsmokers with fold change (0.0001 and 0.007, respectively). In conclusion, this study provided proof that hubble-bubble smoking has a negative impact on global DNA methylation, DNA fragmentation, protamine deficiency, and the transcription of protamine and histone genes in spermatozoa, and these findings influence negatively males' fecundity.

Cigarette heavy smoking alters DNA methylation patterns and gene transcription levels in humans spermatozoa

Tobacco smoking is considered the most common reason of death and infertility around the world. This study was designed to assess the impact of tobacco heavy smoking on sperm DNA methylation patterns and to determine whether the transcription level of ALDH3B2, PTGIR, PRICKLE2, and ALS2CR12 genes is different in heavy smokers compared to non-smokers. As a screening study, the 450 K array was used to assess the alteration in DNA methylation patterns between heavy smokers (n = 15) and non-smokers (n = 15). Then, four CpGs that have the highest difference in methylation level (cg16338278, cg08408433, cg05799088, and cg07227024) were selected for validation using deep bisulfite sequencing in an independent cohort of heavy smokers (n = 200) and non-smokers (n = 100). A significant variation was found between heavy smokers and non-smokers in the methylation level at all CpGs within the PRICKLE2 and ALS2CR12 gene amplicon (P < 0.001). Similarly, a significant variation was found in the methylation level at nine out of thirteen CpGs within the ALDH3B2 gene amplicon (P < 0.01). Additionally, eighteen CpGs out of the twenty-six within the PTGIR gene amplicon have a significant difference in the methylation level between heavy smokers and non-smokers (P < 0.01). The study showed a significant difference in sperm global DNA methylation, chromatin non-condensation, and DNA fragmentation (P < 0.001) between heavy smokers and non-smokers. A significant decline was shown in the transcription level of ALDH3B2, PTGIR, PRICKLE2, and ALS2CR12 genes (P < 0.001) in heavy smokers. In conclusion, heavy smoking influences DNA methylation at several CpGs, sperm global DNA methylation, and transcription level of the PRICKLE2, ALS2CR12, ALDH3B2, and PTGIR genes, which affects negatively the semen parameters of heavy smokers.

Influence of tobacco cigarette heavy smoking on DNA methylation patterns and transcription levels of MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A genes in human spermatozoa

Background

Tobacco smoking is considered as one of the lifestyles factors that influence the sperm DNA methylation and global sperm DNA methylation and that may affect the sperm phenotype. This study was performed to investigate whether tobacco cigarette heavy smoking influences sperm DNA methylation patterns and semen parameters and to determine whether there is an alteration in the transcription level of MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A genes in heavy smokers compared to non-smokers. Thirty samples were subjected to 450K arrays as a screening study to assess the variation in sperm DNA methylation levels between heavy smokers and non-smokers. Five CpG sites have the highest difference in methylation levels (cg07869343, cg05813498, cg09785377, cg06833981, and cg02745784), which are located in the MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A genes, respectively, and were selected for further analysis using deep bisulfite sequencing in 280 independent samples (120 proven non-smokers and 160 heavy smokers) with a mean age of 33.8 ± 8.4 years. The global sperm DNA methylation, sperm DNA fragmentation, and chromatin non-condensation were evaluated also.

Results

A significant increase was found in the methylation level at seven, three, and seventeen CpGs within the GAA, ANXA2, and MAPK8IP3 genes amplicon, respectively (P< 0.01) in heavy smokers compared to non-smokers. Additionally, a significant increase was found in the methylation levels at all CpGs within PRRC2A and PDE11A gene amplicon (P< 0.01). A significant increase was found in the level of sperm chromatin non-condensation, DNA fragmentation, and global DNA methylation (P < 0.001) in heavy smokers compared to non-smokers.

Conclusion

These results indicate that tobacco cigarette smoking can alter the DNA methylation level at several CpGs, the status of global DNA methylation, and transcription level of the following genes “MAPK8IP3, GAA, ANXA2, PRRC2A, and PDE11A” in human spermatozoa. These findings may affect negatively semen parameters and men’s fertility.

Potential effect of tobacco cigarettes smoking on global DNA methylation status and protamines transcripts in human spermatozoa

Background

Epigenetics refers to an alteration in gene expression without alteration in the sequence of DNA and this process may be affected by environmental factors and lifestyle like cigarette smoking. This study was designed to evaluate the potential effect of cigarette smoking on the global DNA methylation status and the transcription level of protamine 1 and protamine 2 in human spermatozoa. A total of 188 semen samples were collected from men with a mean age of 34.9 ± 5.8 years old (98 heavy smokers and 90 non-smokers). The DNA and RNA were isolated from purified spermatozoa, then the status of global DNA methylation and the transcription level of protamine 1 and protamine 2 were evaluated using ELISA and qPCR, respectively. The chromatin non-condensation and DNA fragmentation in human spermatozoa were evaluated using chromomycin A3 staining and TUNEL assay, respectively.

Results

A significant increase has been found in the status of global DNA methylation in spermatozoa of heavy smokers compared to non-smokers (7.69 ± 0.69 ng/μl vs. 4.90 ± 0.40 ng/μl, P < 0.001). Additionally, a significant reduction has been found in transcription level of protamine 1 (25.49 ± 0.31 vs. 23.94 ± 0.40, P < 0.001) and protamine 2 (28.27 ± 0.39 vs. 23.45 ± 0.30, P < 0.001) in heavy smokers. A downregulation has been found in the transcription level of protamine 1 and protamine 2 with a fold change of 0.497 and 0.047, respectively. A significant increase has been shown in the level of DNA fragmentation and chromatin non-condensation in heavy smokers compared to non-smokers (P < 0.001). On the other hand, a significant positive correlation has been found between sperm chromatin non-condensation, sperm DNA fragmentation, transcription level of protamine 1, transcription level of protamine 2, and global DNA methylation status (r = 0.304, P < 0.001; r = 0.399, P < 0.001; r = 0.216, P = 0.003; r = 0.494, P < 0.001, respectively).

Conclusion

Tobacco cigarette smoking has a potential influence on the global DNA methylation and the transcription level of protamine genes in human spermatozoa, and consequently, affect negatively on the semen parameters.

Predictive factors of ovarian response to GnRH antagonist stimulation protocol: AMH and age are potential candidates

Background

Prediction of ovarian response prior to the ovarian stimulation cycle is useful in determining the optimal starting dose of recombinant follicle-stimulating hormone (r-FSH). This study was designed to (I) evaluate which of the following parameters (age, AMH, and FSH) can be used as a predictor of ovarian response to GnRH antagonist stimulation protocol, (II) determine the cutoff value of AMH and age for predicting poor and high ovarian response, and (III) investigate the relationship between age, AMH level, and other clinical parameters. It is a retrospective study. A total of 318 women with a mean age of 28.2 ± 5.9 years old were included in this study. Hormone levels (FSH, LH, PRL, E2, and AMH) and the number of collected oocytes were determined. Based on the number of retrieved oocytes, the participants were divided into three groups: poor response (oocytes < 4, n= 51), normal response (oocytes 4–14, n= 192), and high response (oocytes > 14, n= 75).

Results

A significant increase has been found in AMH level and number of retrieved oocytes and mature oocytes from low to normal and high ovarian response group (P < 0.001). Also, the age in the poor ovarian response group was significantly greater than normal and high ovarian response groups (P < 0.001). A significant positive correlation has been found between the number of retrieved oocytes and mature oocytes and level of AMH (P < 0.001). The receiver operating characteristic (ROC) curves showed that both AMH and age had the highest accuracy in the prediction of poor ovarian response with a cutoff value < 1.45 and > 31.5 years, respectively. Additionally, the ROC analysis has shown that the AMH had the highest accuracy, followed by age in the prediction of high ovarian response with a cutoff value > 3.55 and < 27.5 years, respectively.

Conclusions

This study demonstrates that AMH level and women’s age may be used as potential predictors of ovarian response to GnRH antagonist stimulation protocol.

Testosterone and Gonadotropins in Infertile Men with Sertoli Cell Only Syndrome from Gaza Strip

Aim: To assess serum testosterone and gonadotropins in Sertoli cell only syndrome patients from Gaza Strip.Methods: Based on testicular biopsy, a cross section of 74 Sertoli cell only syndrome patients were enrolled in the study. Age matched 44 fertile men were served as controls. Patients and controls were questioned for their medical history. Blood samples were drawn and serum testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were determined by enzyme-linked immunosorbent assay. Data were computer analyzed using SPSS/PC, version 18.0.Results: Varicocele and hormonal problems were significantly more frequent among patients than controls (P<0.05). Serum testosterone was significantly lower in patients compared to controls (1.7±1.3 versus 5.0±2.2 ng/ml, P=0.000). In contrast, LH and FSH were significantly higher in patients than controls (12.8±9.7 and 20.8±14.8 mlU/ml versus 6.3±3.1 and 7.7±3.9 mlU/ml, P=0.000, respectively). Hypergonadotrophic hypogonadism and hypogonadotrophic hypogonadism patients showed lower levels of testosterone compared to the normal reference value (0.9±0.5 and 0.5±0.4 ng/ml versus 2.0-7.0 ng/ml). Higher levels of LH and FSH were recorded in hypergonadotrophic hypogonadism (24.5±2.6 and 37.4±6.7 mlU/ml) compared to the reference values of 2.0-13.0 and 2.5-10.0 mlU/ml, respectively whereas LH and FSH levels were lower in hypogonadotrophic hypogonadism (0.6±0.4 and 0.6±0.5 mlU/ml, respectively). In this context, all hypergonadotrophic hypogonadism and hypogonadotrophic hypogonadism patients showed abnormal levels of testosterone, LH and FSH.Conclusions: Abnormal levels of serum testosterone, LH and FSH, particularly in hypergonadotrophic hypogonadism and hypogonadotrophic hypogonadism were identified in infertile men with Sertoli cell only syndrome from Gaza Strip.J MEDICINE January 2017; 18 (1) : 21-26