Smoking and reproduction

Tobacco or marijuana use and infertility: a committee opinion

In the United States, approximately 21% of adults report some form of tobacco use, although 18% report marijuana use. Although the negative impact of tobacco use in pregnancy is well documented, the impact of tobacco and marijuana on fertility and reproduction is less clear. This committee opinion reviews the potential deleterious effects of tobacco, nicotine, and marijuana use on conception, ovarian follicular dynamics, sperm parameters, gamete mutations, early pregnancy, and assisted reproductive technology outcomes. It also reviews the current status of tobacco smoking cessation strategies. This document replaces the 2018 American Society for Reproductive Medicine Practice Committee document entitled Smoking and Infertility: a committee opinion (Fertil Steril 2018).

The protective effects of curcumin against cigarette smoke-induced toxicity: A comprehensive review

Cigarette smoking (CS) is a crucial modifiable risk of developing several human diseases and cancers. It causes lung, bladder, breast, and esophageal cancers, respiratory disorders, as well as cardiovascular and metabolic diseases. Because of these adverse health effects, continual efforts to decrease the prevalence and toxicity of CS are imperative. Until the past decades, the impacts of natural compounds have been under investigation on the harmful effects of CS. Turmeric (Curcuma longa), a rhizomatous herbaceous perennial plant that belongs to the Zingiberaceae family, is the main source of curcumin. This review is an attempt to find out the current knowledge on CS's harmful effects and protective potential of curcumin in the pulmonary, liver, brain, gastrointestinal, and testis organs. According to the present review, simultaneous consumption of curcumin and CS can attenuate CS toxicities including chronic obstructive pulmonary disease, gastrointestinal toxicity, metabolic diseases, testis injury, and neurotoxicity. Moreover, curcumin suppresses carcinogenesis in the skin, liver, lungs, breast, colon, and stomach. Curcumin mediates these protective effects through antioxidant, anti-inflammatory, anti-apoptotic, and anti-carcinogenicity properties.

Skeletal and neurological risks demonstrated in zebrafish due to second-hand cigarette smoke and the neutralization of luteolin

BACKGROUND

Cigarette smoke exposure poses significant health risks, including oxidative stress, inflammation, tissue damage, and neurodegenerative diseases. Luteolin, a natural flavonoid known for its antioxidant and anti-inflammatory properties, is of interest in countering these effects.

AIM

This study aims to assess luteolin's protective potential against cigarette smoke extract (CSE) in adult zebrafish.

MATERIALS AND METHODS

Adult zebrafish were exposed to CSE for 15 days, inducing smoke-related damage. Subsequent luteolin treatment assessed its impact. Evaluations included antioxidant enzymes (SOD, CAT), nitric oxide (NO), LDH activity (cellular damage), tissue integrity, fibrosis, amyloid plaque accumulation, and CSE component analysis via HPLC.

KEY FINDINGS

CSE exposure heightened oxidative stress, reducing SOD and CAT activity and elevating NO levels, leading to cellular damage and tissue disruption, notably fibrosis and amyloid plaque accumulation. Inflammatory markers TNF-α and IL-1β also increased. Luteolin treatment restored SOD and CAT activity, reduced LDH and NO activity, counteracting oxidative damage. It also mitigated fibrosis and reduced amyloid plaque deposition, preserving tissue integrity. Luteolin reduced TNF-α and IL-1β levels and CSE components, displaying anti-inflammatory effects.

SIGNIFICANCE

This study underscores luteolin's potential as a protective agent against cigarette smoke-induced harm in a zebrafish model.

Identification of occupations susceptible to high exposure and risk associated with multiple toxicants in an observational study: National Health and Nutrition Examination Survey 1999-2014

Occupational exposures to toxicants are estimated to cause over 370 000 premature deaths annually. The risks due to multiple workplace chemical exposures and those occupations most susceptible to the resulting health effects remain poorly characterized. The aim of this study is to identify occupations with elevated toxicant biomarker concentrations and increased health risk associated with toxicant exposures in a diverse working US population. For this observational study of 51 008 participants, we used data from the 1999-2014 National Health and Nutrition Examination Survey. We characterized differences in chemical exposures by occupational group for 131 chemicals by applying a series of generalized linear models with the outcome as biomarker concentrations and the main predictor as the occupational groups, adjusting for age, sex, race/ethnicity, poverty income ratio, study period, and biomarker of tobacco use. For each occupational group, we calculated percentages of participants with chemical biomarker levels exceeding acceptable health-based guidelines. Blue-collar workers from "Construction," "Professional, Scientific, Technical Services," "Real Estate, Rental, Leasing," "Manufacturing," and "Wholesale Trade" have higher biomarker levels of toxicants such as several heavy metals, acrylamide, glycideamide, and several volatile organic compounds (VOCs) compared with their white-collar counterparts. Moreover, blue-collar workers from these industries have toxicant concentrations exceeding acceptable levels: arsenic (16%-58%), lead (1%-3%), cadmium (1%-11%), glycideamide (3%-6%), and VOCs (1%-33%). Blue-collar workers have higher toxicant levels relative to their white-collar counterparts, often exceeding acceptable levels associated with noncancer effects. Our findings identify multiple occupations to prioritize for targeted interventions and health policies to monitor and reduce toxicant exposures.

Optimizing natural fertility: a committee opinion

This committee opinion provides practitioners with suggestions for optimizing the likelihood of achieving pregnancy in couples or individuals attempting conception who have no evidence of infertility. This document replaces the document of the same name previously published in 2013 (Fertil Steril 2013;100:631-7).

Comparative effects of combined use of alcohol with cannabis and tobacco on testicular function in rats

Alcoholism has been linked to problems with male reproductive function. The combined effects of alcohol, cannabis, and tobacco were compared in this study. A total of 35 rats were assigned randomly into seven groups A-G: animals in A were administered distilled water. Animals in B-G were either administered alcohol orally (30 ml 40% alcohol) or exposed to smoke from ignited tobacco (exposure to smoke from 0.7 g tobacco for 5 min) or cannabis (exposure to smoke from 0.7 g tobacco and cannabis for 5 min): B (orally administered alcohol), C (exposed to the smoke from tobacco), D (exposed to smoke from cannabis), E (treated with alcohol and exposed to smoke from tobacco), F (treated with alcohol and exposed to smoke from cannabis), G (treated with alcohol and exposed to smokes from tobacco and cannabis). Assays were carried on the testicular homogenate after a 14-day treatment. There was a significant increase in activity of alkaline phosphatase (P ≤ 0.05), concentrations of cholesterol, glutathione reductase, and malondialdehyde in treated rats by the co-administration of alcohol with cannabis and tobacco compared with the control group. The combined treatment also caused degeneration and morphological distortions of testicular cells. The biochemical and histoarchitectural change was due to oxidative damage attributable to the synergistic effects. The high binding energy of tetrahydrocannabinol ligand to prostate acid phosphatase may be a prediction that the ligand can have an inhibitory effect on the function of enzymes in the prostate.

Impact of smoking on heavy metal contamination and DNA fragmentation

Tobacco is smoked by different techniques through cigarette and shisha smoking. The prevalence of tobacco is considered one of the major threats to public health. This study aims to assess the effect of cigarette, shisha, and mixed (cigarette/shisha) smoking on heavy metal contamination in hair samples, hair loss, and DNA fragmentation, to correlate age, incidence of hair loss, and smoking duration with the amount of accumulated metals and the DNA fragmentation, and to correlate the level of heavy metal contamination with DNA fragmentation. This study was implemented in Saudi Arabia among sixty males divided into four groups (15/group): control and cigarette, shisha, and mixed smokers. Heavy metal contamination in hair samples and urinary DNA levels were assayed. All metal and urinary DNA levels were significantly elevated in cigarette, shisha, and mixed smokers compared to non-smokers. Hair loss was also higher among smokers especially among participants with high DNA concentrations. There were positive significant correlations of age and incidence of hair loss with urinary DNA concentration. There were positive significant correlations between urinary DNA concentration and all heavy metal levels. Cigarette, shisha, and mixed smoking trigger metal contamination, DNA fragmentation, and hair loss. Moreover, hair loss was observed to be associated with Sb, Cd, and Ni as well as urinary DNA level, while age was associated only with lead and urinary DNA levels. The duration of smoking had a major impact on Pb and Sb levels. Finally, contamination with all six metals was significantly associated with DNA fragmentation.

Smoking and pregnancy: Epigenetics and developmental origins of the metabolic syndrome

Maternal smoking causes lower birth weight, birth defects, and other adverse pregnancy outcomes. Epidemiological evidence over the past four decades has grown stronger and the adverse outcomes attributed to maternal smoking and secondhand smoke exposure have expanded. This review presents findings of latent and persistent metabolic effects in offspring of smoking mothers like those observed in studies of maternal undernutrition during pregnancy. The phenotype of offspring of smoking mothers is like that associated with maternal undernutrition. Born smaller than offspring of nonsmokers, these children have increased risk of being overweight or obese later. Plausible mechanisms include in utero hypoxia, nicotine-induced reductions in uteroplacental blood flow, placental toxicity, or toxic growth restriction from the many toxicants in tobacco smoke. Studies have reported increased risk of insulin resistance, type 2 diabetes and hypertension although the evidence here is weaker than for overweight/obesity. Altered DNA methylation has been consistently documented in smoking mothers' offspring, and these epigenetic alterations are extensive and postnatally durable. A causal link between altered DNA methylation and the phenotypic changes observed in offspring remains to be firmly established, yet the association is strong, and mediation analyses suggest a causal link. Studies examining expression patterns of affected genes during childhood development and associated health outcomes should be instructive in this regard. The adverse effects of exposure to tobacco smoke during pregnancy now clearly include permanent metabolic derangements in offspring that can adversely affect life-long health.

Effects of N-nitro L-arginine methyl ester and α-tocopherol on testicular oxidative stress caused by exposure to cigarette smoke

Testis is a rich organ with blood vessels. For this reason, it is possible that the toxic substances of the cigarette carried in the blood change the balance between the oxidant and the antioxidant system in this organ. In this study, it was aimed to investigate the effects of N-nitro L-arginine methyl ester and α-tocopherol on testicular oxidative stress caused by exposure to cigarette smoke. 45 wistar male rats were used in the study. Five groups were formed: control, cigarette smoke, cigarette smoke + α-tocopherol, cigarette smoke + N-nitro L-arginine methyl ester and cigarette smoke + α-tocopherol + N-nitro L-arginine methyl ester. Biochemical and histological evaluations were performed to determine the damage caused by cigarette smoke. It was observed that there were structural and functional disturbances at the cellular and hormonal level in the smoking group. Biochemical evaluations showed that cellular damage was reduced in treatment groups. Histological examinations were revealed that the damage caused by cigarette smoke exposure was eliminated in treatment groups. As a result of our study, we think that oxidative damage and hormonal irregularity in the testes tissue caused by cigarette smoke exposure can be improved with α-tocopherol and N-nitro L-arginine methyl ester application.

Volatile organic compounds and good laboratory practices in the in vitro fertilization laboratory: the important parameters for successful outcome in extended culture

PURPOSE

This study aims to describe the role of implementing good laboratory practices to improve in vitro fertilization (IVF) outcomes which are of great interest for practitioners dealing with infertility.

METHODS

Certain modifications were introduced in May 2015 in our IVF laboratory like high-efficiency particulate air CODA system, steel furniture instead of wooden, use of new disinfectants like oosafe, and restriction of personnel entry along with avoidance of cosmetics like perfume to improve pregnancy rates. Volatile organic compound (VOC) meter reading was monitored at two time points and five different places in the laboratory to compare the embryonic development parameters before (group A: July 2014-April 2015) and after (group B: July 2015-April 2016) remodeling.

RESULTS

The IVF outcomes from 1036 cycles were associated in this study. Reduction in VOC meter readings, enhanced air quality, improvement in blastocyst formation rate, implantation, and clinical pregnancy rate were observed in the laboratory after implementation of new facilities. Results illustrated that the attention must be focused on potential hazards which expose laboratories to elevated VOC levels. Blastocyst formation rate increased around 18%. Implantation rate, clinical pregnancy rate, and live birth rate increased by around 11, 10, and 8%, respectively.

CONCLUSION

In conclusion, with proper engineering and material selection, we have been able to reduce chemical contamination and adverse effects on culture with optimized IVF results.

SUPPORT

None.

Nicotine Effects and Receptor Expression on Human Spermatozoa: Possible Neuroendocrine Mechanism

The aim of this experimental study was to investigate the mechanism by which nicotine (NIC) alters spermatozoa and to evaluate the expression of nicotinic receptors (nAChR) subunits in human spermatozoa. We analyzed 30 healthy normozoospermic men. Spermatozoa were incubated with NIC 100 ng/ml and the nAChR antagonist, hexamethonium (HEX) (0, 100, 1,000, 10,000 ng/ml) for 3 and 24 h. The following sperm parameters evaluated: (a) progressive motility; (b) mitochondrial membrane potential (MMP); (c) chromatin compactness; (d) externalization of phosphatidylserine (PS); (e) late apoptosis; (f) viability; (g) DNA fragmentation; (h) degree of lipid peroxidation (LP) by flow cytometry; (i) nAChR subunits expression by quantitative Real Time PCR and (j) protein expression evaluation by Western blot analysis. HEX fully antagonized the effects of NIC both after 3 and 24 h of incubation with significant improvement (p < 0.05) of sperm progressive motility, MMP, abnormal chromatin compactness, PS externalization, late apoptosis and DNA fragmentation, already at the concentration of HEX 100 ng/ml. The degree of LP increased after incubation with NIC in raw semen but this effect was fully antagonized (p < 0.05) by HEX after 3 and 24 h of incubation. Finally, 8 nAChR subunits mRNA (α1, α3, α4, α6, α7, β2, β4, and δ) were found expressed in all samples examined, but only α7 subunit is translated, making an homomer receptor, in non-smokers subjects. The effects of NIC on sperm function are mediated by interaction with a specific nicotinic receptor. The presence of nAChR subunits suggests the presence of a neuroendocrine mechanism on human spermatozoa.

Alcohol, cigarette smoking, and ovarian reserve in reproductive-age African-American women

BACKGROUND

Although alcohol consumption and cigarette smoking are common behaviors in reproductive-age women, little is known about the impact of consumption patterns on ovarian reserve. Even less is known about the effects of smoking and alcohol use in reproductive-age African-American women.

OBJECTIVE

The objective of the study was to examine the impact of the patterns of alcohol intake and cigarette smoking on anti-Müllerian hormone levels as a marker of ovarian reserve in African-American women.

STUDY DESIGN

This was a cross-sectional analysis from the baseline clinical visit and data collection of the Study of Environment, Lifestyle, and Fibroids performed by the National Institute of Environmental Health Sciences. A total of 1654 volunteers, aged 23-34 years, recruited from the Detroit, Michigan community completed questionnaires on alcohol intake and cigarette smoking and provided serum for anti-Müllerian hormone measurement. Multivariable linear and logistic regressions were used as appropriate to estimate the effect of a range of exposure patterns on anti-Müllerian hormone levels while adjusting for potential confounders including age, body mass index, and hormonal contraception.

RESULTS

Most participants were alcohol drinkers (74%). Of those, the majority (74%) engaged in binge drinking at least once in the last year. Women who reported binge drinking twice weekly or more had 26% lower anti-Müllerian hormone levels compared with current drinkers who never binged (95% confidence interval, -44, -2, P < .04). Other alcohol consumption patterns (both past and current) were unrelated to anti-Müllerian hormone. The minority of participants currently (19%) or formerly (7%) smoked, and only 4% of current smokers used a pack a day or more. Neither smoking status nor second-hand smoke exposure in utero, childhood, or adulthood was associated with anti-Müllerian hormone levels.

CONCLUSION

Results suggest that current, frequent binge drinking may have an adverse impact on ovarian reserve. Other drinking and smoking exposures were not associated with anti-Müllerian hormone in this cohort of healthy, young, African-American women. A longitudinal study of how these common lifestyle behaviors have an impact on the variability in age-adjusted anti-Müllerian hormone levels is merited.

Optimizing natural fertility: a committee opinion

This Committee Opinion provides practitioners with suggestions for optimizing the likelihood of achieving pregnancy in couples/individuals attempting conception who have no evidence of infertility. This document replaces the document of the same name previously published in 2013, Fertil Steril 2013;100(3):631-7.

Association of tobacco use and other determinants with pregnancy outcomes: a multicentre hospital-based case-control study in Karachi, Pakistan

OBJECTIVES

The study aimed to identify the effects of maternal tobacco consumption during pregnancy and other factors on birth outcomes and obstetric complications in Karachi, Pakistan.

DESIGN

A multicentre hospital-based case-control study.

SETTING

Four leading maternity hospitals of Karachi.

PARTICIPANTS

A random sample of 1275 women coming to the gynaecology and obstetric department of selected hospitals for delivery was interviewed within 48 hours of delivery from wards. Cases were women with adverse birth outcomes and obstetric complications, while controls were women who had normal uncomplicated delivery.

PRIMARY AND SECONDARY OUTCOME MEASURES

Adverse birth outcomes (preterm delivery, low birth weight, stillbirth, low Apgar score) and obstetric complications (antepartum haemorrhage, caesarean section, etc).

RESULTS

Final multiple logistic regression analysis revealed that with every 1 year increase in age the odds of being a case was 1.03 times as compared with being a control. Tobacco use (adjusted OR (aOR): 2.24; 95% CI 1.56 to 3.23), having no slits in the kitchen (proxy indicator for indoor air pollution) (aOR=1.90; 95% CI 1.05 to 3.43), gravidity (aOR=0.83; 95% CI 0.73 to 0.93), non-booked hospital cases (aOR=1.87; 95% CI 1.38 to 2.74), history of stillbirth (aOR=4.06; 95% CI 2.36 to 6.97), miscarriages (aOR=1.91; 95% CI 1.27 to 2.85) and preterm delivery (aOR=6.04; 95% CI 2.52 to 14.48) were significantly associated with being a case as compared with control.

CONCLUSIONS

This study suggests that women who had adverse pregnancy outcomes were more likely to have exposure to tobacco, previous history of adverse birth outcomes and were non-booked cases. Engagement of stakeholders in tobacco control for providing health education, incorporating tobacco use in women in the tobacco control policy and designing interventions for tobacco use cessation is warranted. Prenatal care and health education might help in preventing such adverse events.

Ameliorating effects of curcumin on nicotine-induced mice testes

BACKGROUND/AIM

The aim of this study was to determine the antioxidative effect of curcumin on nicotine-induced mice testis.

MATERIALS AND METHODS

Sixty Swiss albino male mice were divided into five groups, each containing 12 mice. The first group was used as a control. To induce toxicity in the second and third group, nicotine (0.4 mg/kg/day) was injected intraperitoneally into mice for 14 and 28 days, respectively. The mice in the fourth and fifth group were injected with nicotine (0.4 mg/kg/day) and orally treated with curcumin (200 mg/kg) for 14 and 28 days, respectively. Testosterone levels were measured from blood samples and testis tissues were examined under light and electron microscopes.

RESULTS

Light and electron microscopic examinations of the nicotine-induced groups showed evident degenerations in spermatogenic cells, Sertoli cells, and Leydig cells. The groups treated with curcumin had less testicular alterations. The mice that were sacrificed after 28 days in the groups treated with curcumin showed minor degenerations. Furthermore, the median levels of testosterone significantly decreased in the nicotine-induced groups in comparison with those in the control group.

CONCLUSION

The results indicated that curcumin might be a potential therapeutic agent for testicular injury caused by nicotine addiction.

Smoking and Male Infertility: An Evidence-Based Review

Many studies have reported that the contents of cigarette smoke negatively affect sperm parameters, seminal plasma, and various other fertility factors. Nevertheless, the actual effect of smoking on male fertility is not clear. The effect of smoking on semen parameters is based on the well-established biological finding that smoking increases the presence of reactive oxygen species, thereby resulting in oxidative stress (OS). OS has devastating effects on sperm parameters, such as viability and morphology, and impairs sperm function, hence reducing male fertility. However, not all studies have come to the same conclusions. This review sheds light upon the arguable association between smoking and male fertility and also assesses the impact of non-smoking routes of tobacco consumption on male infertility. It also highlights the evidence that links smoking with male infertility, including newly emerging genetic and epigenetic data, and discusses the clinical implications thereof.

Infertility and miscarriage: common pathways in manifestation and management

The relationship between miscarriage and fertility is complex. While most healthcare settings treat miscarriage as a problem of subfertility in assisted reproduction units, others believe that miscarriage occurs in super-fertile women. Infertile women undergoing assisted reproduction are at a greater risk of having a miscarriage especially at an advanced age compared with women conceiving naturally. Aberrant expression of immunological factors and chromosomal abnormalities underlie both infertility and miscarriage. Common risk factors include increased maternal age, obesity, smoking, alcohol, pre-existing medical conditions and anatomical abnormalities of the reproductive system. Management pathways of both conditions may be similar with pre-implantation genetic testing and assisted reproductive technology used in both conditions. This paper discusses the synergies and differences between the two conditions in terms of their epidemiology, etiopathogenesis, risk factors and management strategies. The two conditions are related as degrees of severity of reproductive failure with common pathways in manifestation and management.

The impact of lifestyle modifications, diet, and vitamin supplementation on natural fertility

BACKGROUND

Infertility is a relatively common condition. When patients are confronted with this diagnosis, there are medical, psychological, and financial sequelae. Patients often wonder if there is anything they can do to optimize their natural fertility or increase the effectiveness of infertility treatments.

FINDINGS

If there is a clear impact on fertility, such as with smoking and alcohol, cessation should be advised. Similarly, weight loss should be recommended if the BMI is in the overweight and obese category, and weight gain should be recommended for an underweight BMI. The evidence surrounding other lifestyle modifications is less clear. There are conflicting data regarding an optimal fertility diet and consumption of vitamins and supplements. Antioxidants seem to improve semen parameters in men, but the effect on female fertility is less clear. If conflicting evidence exists, such as with caffeine consumption or exercise, moderation should be emphasized. Finally, the diagnosis of infertility and subsequent fertility treatments are stressful for both partners. The psychological aspects should not be ignored and methods such as yoga and cognitive behavioral therapy may be beneficial.

CONCLUSION

Continued research will determine the optimal lifestyle modifications to achieve pregnancy.

Modeling the effect of cigarette smoke on hexose utilization in spermatocytes

We set out to determine whether the addition of an aryl hydrocarbon receptor (AHR) antagonist has an effect on glucose/fructose utilization in the spermatocyte when exposed to cigarette smoke condensate (CSC). We exposed male germ cells to 5 and 40 μg/mL of CSC ± 10 μmol/L of AHR antagonist at various time points. Immunoblot expression of specific glucose/fructose transporters was compared to control. Radiolabeled uptake of 2-deoxyglucose (2-DG) and fructose was also performed. Spermatocytes utilized fructose nearly 50-fold more than 2-DG. Uptake of 2-DG decreased after CSC + AHR antagonist exposure. Glucose transporters (GLUTs) 9a and 12 declined after CSC + AHR antagonist exposure. Synergy between CSC and the AHR antagonist in spermatocytes may disrupt the metabolic profile in vitro. Toxic exposures alter energy homeostasis in early stages of male germ cell development, which could contribute to later effects explaining decreases in sperm motility in smokers.

Prevalence of abnormal spermatozoa in tobacco chewing sub-fertile males

AIM

The aim of the following study is to find out the prevalence of abnormal spermatozoa and associated functional parameters in clinical semen samples of sub-fertile males with the tobacco chewing habit.

SETTINGS AND DESIGN

Retrospective study was conducted at infertility unit of a tertiary health care center, in a period of 3 years.

MATERIALS AND METHOD

Semen of 642 males were analyzed; of them 194 men (30.2%) were tobacco chewers and they were grouped according to their intensity of chewing (<10 and ≥ 10 packets/day). Counts, motility, vitality, and morphology of sperms were analyzed.

RESULTS

In tobacco chewers, 66% of subjects were oligozoospermic, 85% asthenozoospermic and 28% teratozoospermic. Sperm counts (odds ratio [OR] =2.2; 95% confidence interval [CI]: 1.5-3.09), motility (OR = 3.2; 95% CI: 2.05-4.9), and normal morphology (OR = 8.4; 95% CI: 4.9-14.6) were significantly affected (P = 0.001) in tobacco chewers than the non-chewing group. Further, in comparison to the intensity of tobacco chewing, patients with the intensive practice of using ≥10 packets/day had a significant effect on sperm morphology (P = 0.003, OR = 2.7; 95% CI = 1.41-5.08) only. Structural defects in head (P = 0.001) and cytoplasmic residues (P = 0.001) were found to be positively correlated with the intensive chewing, but no significant changes were found in anomalies in mid-piece and tail.

CONCLUSION

The adverse impact of tobacco chewing on semen parameters was evident even with mild chewers, but with the intensive chewing practice, phenotypes of sperms, mainly defects in the head and cytoplasmic residue were severely affected.

The association between smoking and ectopic pregnancy: why nicotine is BAD for your fallopian tube

Epidemiological studies have shown that cigarette smoking is a major risk factor for tubal ectopic pregnancy but the reason for this remains unclear. Here, we set out to determine the effect of smoking on Fallopian tube gene expression. An oviductal epithelial cell line (OE-E6/E7) and explants of human Fallopian tubes from non-pregnant women (n = 6) were exposed to physiologically relevant concentrations of cotinine, the principle metabolite of nicotine, and changes in gene expression analyzed using the Illumina Human HT-12 array. Cotinine sensitive genes identified through this process were then localized and quantified in Fallopian tube biopsies from non-pregnant smokers (n = 10) and non-smokers (n = 11) using immunohistochemistry and TaqMan RT-PCR. The principle cotinine induced change in gene expression detected by the array analysis in both explants and the cell line was significant down regulation (P<0.05) of the pro-apoptotic gene BAD. We therefore assessed the effect of smoking on cell turnover in retrospectively collected human samples. Consistent with the array data, smoking was associated with decreased levels of BAD transcript (P<0.01) and increased levels of BCL2 transcript (P<0.05) in Fallopian tube biopsies. BAD and BCL2 specific immunolabelling was localized to Fallopian tube epithelium. Although no other significant differences in levels of apoptosis or cell cycle associated proteins were observed, smoking was associated with significant changes in the morphology of the Fallopian tube epithelium (P<0.05). These results suggest that smoking may alter tubal epithelial cell turnover and is associated with structural, as well as functional, changes that may contribute to the development of ectopic pregnancy.

General aspects of fertility and infertility

Fertility rates have been declining in most Western nations over the past several decades, although it is not entirely clear if an increased rate of infertility substantially contributes to this. As compared to other species, the reproductive efficiency of humans is relatively low. Factors related to fertility include age, exposure to sexually transmitted diseases, frequency of intercourse, coital timing, as well as diet and lifestyle habits. Infertility is considered a disease due to its major disruption of major organ systems and life functions. An infertility evaluation is recommended after 12 months or more of regular, unprotected intercourse and may be considered after 6 months for those female patients over the age of 35 or with other known abnormalities. A proper infertility evaluation is a comprehensive examination of possibly identifiable infertility factors of both female and male partners, lending itself to the most appropriate and potentially effective treatment.

Associations of variants in MTHFR and MTRR genes with male infertility in the Jordanian population

Folate pathway is expected to play an important role in spermatogenesis since it is involved in DNA synthesis, repair and methylation. The purpose of this study was to examine the association between male infertility and the MTHFR (C677T and A1298C) and MTRR (A66G) polymorphisms. A group of 300 males was recruited in this study from different Jordanian infertility clinics. Of these, 150 cases of infertile men that included oligozoospermia cases (n=45), severe oligozoospermia (n=71) and azoospermia (n=34) were studied. The other 150 males were age matched fertile controls. Genotyping of MTHFR and MTRR polymorphisms was performed using PCR-RFLP technique. The results showed an association between MTHFR 677TT genotype and male infertility (P<0.05). However, the distribution of MTHFR A1298C and MTRR A66G genotypes were not different between the fertile and infertile groups (P>0.05). In addition, none of the examined polymorphisms was related to any of the semen parameters in the infertile group. In conclusion, this study showed that MTHFR C677T polymorphism is associated with male infertility in Jordanians.

Placental DNA methylation alterations associated with maternal tobacco smoking at the RUNX3 gene are also associated with gestational age

AIMS

The developmental origins of health and disease hypothesis states that later-life disease may be influenced by the quality of the in utero environment. Environmental toxicants can have detrimental effects on fetal development, potentially through effects on placental development and function. Maternal smoking during pregnancy is associated with low birth weight, preterm birth and other complications, and exposure to cigarette smoke in utero has been linked to gross pathologic and molecular changes to the placenta, including differential DNA methylation in placental tissue. The aim of this study was to investigate the relationship between maternal smoking during pregnancy, methylation changes in the placenta and gestational age.

MATERIALS & METHODS

We used Illumina(®)'s (CA, USA) Human Methylation27 BeadChip technology platform to investigate the methylation status of 21,551 autosomal, non-SNP-associated CpG loci in DNA extracted from 206 human placentas and examined loci whose variation in methylation was associated with maternal smoking during pregnancy.

RESULTS

We found that methylation patterns of a number of loci within the RUNX3 gene were significantly associated with smoking during pregnancy, and one of these loci was associated with decreased gestational age (p = 0.04).

CONCLUSION

Our findings, demonstrating maternal smoking-induced changes in DNA methylation at specific loci, suggest a mechanism by which in utero tobacco smoke exposure could exert its detrimental effects upon the health of the fetus.

Long-term treatment of hydrogen-rich saline abates testicular oxidative stress induced by nicotine in mice

PURPOSE

The present study was designed to test the hypothesis that long-term treatment with hydrogen-rich saline abated testicular oxidative stress induced by nicotine in mice.

METHODS

The effects of hydrogen-rich saline (6 ml/kg, i.p.), vitamin C (60 mg/kg, i.p.) and vitamin E (100 mg/kg, i.p.) on reproductive system and testicular oxidative levels in nicotine-treated (4.5 mg/kg, s.b.) mice were investigated.

RESULTS

It was found that vitamin C and vitamin E attenuated serum oxidative level, but did not lower testicular oxidative levels in mice subjected to chronic nicotine treatment, and did not improve the male reproductive damage and apoptosis induced by nicotine. Different from normal antioxidants, vitamin C and vitamin E, hydrogen-rich saline abated oxidative stress in testis, and protected against nicotine-induced male reproductive damages.

CONCLUSION

Our results first demonstrated that long-term treatment with hydrogen-rich saline attenuated testicular oxidative level and improved male reproductive function in nicotine-treated mice.

Could zinc prevent reproductive alterations caused by cigarette smoke in male rats?

The aim of the present study was to evaluate the effects of zinc on fertility through semen parameters, testosterone level and oxidative DNA damage to spermatozoa of rats exposed to cigarette smoke. Male Wistar rats (60 days old) were divided into four groups (n = 10 per group): control, cigarette-smoking (20 cigarettes per day), zinc (zinc chloride 20 mg kg–1 day–1) and zinc plus cigarette-smoking (zinc chloride 20 mg kg–1 day–1; 20 cigarettes per day). The treatment was applied for nine weeks and the following parameters were analysed: bodyweight, wet weights of the reproductive organs and the adrenal gland, plasma testosterone concentration, testicular function (seminal analysis and daily sperm production) and sperm DNA oxidative damage. The exposure to cigarette smoke decreased testosterone concentration, the percentage of normal morphology and the motility of spermatozoa. In addition, this exposure increased sperm DNA oxidative damage. Zinc treatment protected against the toxic damage that smoking caused to spermatozoa. This study showed a correlation between smoking and possible male infertility and subfertility, and also that the majority of smoking-induced changes in spermatozoa were prevented by zinc treatment. In conclusion, zinc, an antioxidant and stimulant of cell division, can be indicated as a promising treatment in men with infertility caused by the toxic components of cigarette smoke.

Gender-specific methylation differences in relation to prenatal exposure to cigarette smoke

Epigenetic alterations may mechanistically explain the developmental origins of adult disease, namely the hypothesis that many complex adult chronic diseases originate as a result of conditions encountered in utero. If true, epigenetically regulated imprinted genes, critical to normal growth and development, may partially mediate these outcomes. We determined the influence of in utero exposure to cigarette smoking on methylation at two differentially methylated regions (DMRs) regulating Insulin-like Growth Factor 2 (IGF2) and H19, and how this might relate to birth weight of infants born to 418 pregnant women. Smoking status was ascertained through self-report and medical records. Bisulfite pyrosequencing was used to measure methylation in umbilical cord blood DNAs. Least squares DNA methylation means at each DMR and birth weight were compared between infants of smokers and non-smokers, using generalized linear models. While there were no significant differences at the H19 DMR, infants born to smokers had higher methylation at the IGF2 DMR than those born to never smokers or those who quit during pregnancy (49.5%, SD=8.0 versus 46.6%, SD=5.6 and 45.8%, SD=6.3, respectively; p=0.0002). The smoking-related increase in methylation was most pronounced in male offspring (p for sex interaction=0.03), for whom approximately 20% of smoking-related low birth weight was mediated by DNA methylation at the IGF2 DMR. Our findings suggest that IGF2 DMR plasticity is an important mechanism by which in utero adjustments to environmental toxicants are conferred. Larger studies to replicate these findings are required.

Cotinine exposure increases Fallopian tube PROKR1 expression via nicotinic AChRalpha-7: a potential mechanism explaining the link between smoking and tubal ectopic pregnancy

Tubal ectopic pregnancy (EP) is the most common cause of maternal mortality in the first trimester of pregnancy; however, its etiology is uncertain. In EP, embryo retention within the Fallopian tube (FT) is thought to be due to impaired smooth muscle contractility (SMC) and alterations in the tubal microenvironment. Smoking is a major risk factor for EP. FTs from women with EP exhibit altered prokineticin receptor-1 (PROKR1) expression, the receptor for prokineticins (PROK). PROK1 is angiogenic, regulates SMC, and is involved in intrauterine implantation. We hypothesized that smoking predisposes women to EP by altering tubal PROKR1 expression. Sera/FT were collected at hysterectomy (n=21). Serum levels of the smoking metabolite, cotinine, were measured by enzyme-linked immunosorbent assay. FTs were analyzed by q-RT-PCR, immunohistochemistry, and Western blotting for expression of PROKR1 and the predicted cotinine receptor, nicotinic acetylcholine receptor α-7 (AChRα-7). FT explants (n=4) and oviductal epithelial cells (cell line OE-E6/E7) were treated with cotinine and an nAChRα-7 antagonist. PROKR1 transcription was higher in FTs from smokers (P<0.01). nAChRα-7 expression was demonstrated in FT epithelium. Cotinine treatment of FT explants and OE-E6/E7 cells increased PROKR1 expression (P<0.05), which was negated by cotreatment with nAChRα-7 antagonist. Smoking targets human FTs via nAChRα-7 to increase tubal PROKR1, leading to alterations in the tubal microenvironment that could predispose to EP.

Prenatal exposure to maternal and paternal smoking on attention deficit hyperactivity disorders symptoms and diagnosis in offspring

The study examined the effect of maternal and paternal smoking during pregnancy on the child's inattention and hyperactivity/impulsivity symptoms, and the risk for attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). Generalized estimating equations, incorporating data from multiple informants (parents and teachers), was used to evaluate levels of ADHD as a function of parental smoking. The risk for ADHD, ODD, and comorbid ADHD and ODD was evaluated using polytomous logistic regression. We found that maternal, but not paternal, smoking was significantly associated with elevated inattention, hyperactivity/impulsivity, and total ADHD symptoms in children. Children of smoking, relative to nonsmoking, mothers had a significant increased risk for comorbid ADHD and ODD and ADHD, but not ODD. Although father's smoking was not associated with an increased risk, as it strongly influenced mothers' smoking, intervention for both parents may be most effective in preventing the pathway to ADHD-related problems in the children.

Cigarette smoking as a cause of delay in conception

Epidemiological studies relating cigarette smoking to the ability to conceive and maintain a pregnancy provide information on the clinical significance of smoking on reproductive health. Cigarette smoking by females has significantly increased in the decades after World War II, and now has an average initiation at ages 18–20 years. Maternal smoking is a hazard to the general health, the reproductive health and the life of both mother and child. Gestational smoking renders the fetus a passive smoker. This can result in fetal and neonatal death and in reduced fecundity of adult daughters.

Effects of environmental tobacco smoke in vivo on rhesus monkey semen quality, sperm function, and sperm metabolism

The objective of this study was to use a non-human primate model to examine the effect of environmental tobacco smoke (ETS) in vivo on semen quality, sperm function, and sperm metabolism. Four adult rhesus macaques (Macaca mulatta) were exposed to ETS for six months, and semen samples were collected every week for evaluation. ETS exposure in vivo did not affect semen quality and sperm function. The sperm X:Y chromosome ratio remained unchanged after ETS exposure. The sex ratio of the embryos fertilized by ETS-exposed males was not different from the control male. However, sperm showed changes in metabolome detected by NMR during the ETS exposure. We concluded that with the duration and level of ETS exposure in this study, semen quality and sperm function were not affected, whereas sperm did undergo metabolic changes with ETS exposure in vivo.

Smoking and infertility

Approximately 30% of reproductive age women and 35% of reproductive age men in the United States smoke cigarettes. Substantial harmful effects of cigarette smoke on fecundity and reproduction have become apparent but are not generally appreciated.

Optimizing natural fertility

This Committee Opinion provides practitioners with suggestions for optimizing the likelihood of achieving pregnancy in couples attempting conception who have no evidence of infertility.

Is there an ideal stimulation regimen for IVF for poor responders and does it change with age?

PURPOSE

To determine whether there is a superior treatment modality for 'poor' responders.

METHOD

Retrospective analysis of three stimulation regimens, with patients stratified based on age, stimulation regime and response in previous cycles ("poor' responder or "non poor" responder). Fertilisation, embryo utilisation and clinical pregnancy rates were assessed. There were a total of 1,608 cycles in the 'poor' responder and 8,489 cycles in the 'non poor' responder groups.

RESULTS

In 'poor' responders there was no significant difference in fertilisation rate, nor utilisation rate between the three stimulation regimes and no differences in the pregnancy rate/initiated cycle irrespective of age and stimulation regimen in any of the groups. 'Non poor' responders had a significantly greater pregnancy rate/initiated cycle for all stimulation regimens in both age groups compared with 'poor' responders.

CONCLUSION

This large retrospective study of 'poor' responders has not shown a difference in pregnancy rates/initiated cycle between stimulation regimens.

Smoking in pregnancy

During nine months of pregnancy, a woman who smokes 20 cigarettes each day will inhale nicotine, tar and carbon monoxide more than 50 000 times. This smoke contains chemicals known to be mutagenic and carcinogenic and will interfere with the normal growth and development of her child. Recent studies have revealed disturbing long-term consequences for the offspring. This article reviews the constituents of cigarette smoke, the effects of tobacco usage on the pregnancy, child and placenta, and strategies by which smoking during pregnancies may be prevented.