Wednesday, 08 October 2008
BERKELEY, CA (UroToday.com) - A variety of testicular pathologies to include testicular cancer, cryptorchidism and defective spermatogenesis have been increasing. While genetic factors play a role, growing evidence suggests that the testicle is damaged by environment and lifestyle-related factors either at prenatal or at puberty times. While the reproductive effects of tobacco, alcohol and sedentary lifestyle have not been well documented, other exposures such as excessive heat, ionizing radiation, dibromochloropropane, estrogens and anabolic steroids may induce severe damage to adult testicles. In this paper, we review lifestyle factors which may effect future male fertility and describe new findings on the effects of cell phone derived electromagnetic on male reproductive function.
Certain lifestyles engender more risk of excessive heat exposure to the testes. Exposure to hot occupational environment (bakers, welders, foundry workers), sedentary work habits, long periods of car travel,and tight clothing, can disrupt regulation of intrascrotal temperature and lead to increased testicular temperature that can affect spermatogenesis. Saleh et al demonstrated cigarette smoking leads to increases in reactive oxygen species (ROS) level and decreases in total antioxidant capacity (TAC) with disturbed ROS/TAC score. Smoking is associated with elevated levels of seminal leukocytes and the resulting oxidative stress due to ROS generation by activated leukocytes. Various components of cigarette smoke (i.e., polycyclic aromatic hydrocarbons) and smoking metabolites may act as chemotactic stimuli and thereby induce an inflammatory response, recruitment of leukocyte and subsequent generation of ROS. Recently, reports showed mild asthenozoospermia may be an early indicator of reduced semen quality in light smokers while heavy smokers showed profound teratozoospermia.
The effect of environmental toxicants and endocrine active compounds on male reproductive health has been the subject of extensive study. Various animal and human studies reported lead exposure can cause severe adverse effects on male reproductive organs. Lead causes excessive oxidative stress by interfering with antioxidant enzymes and also by its effect on cell membrane polyunsaturated fatty acids (PUFA).
The newest environmental exposure of concern to reproductive health relates to cell phone derived radiation. As energy carried by cell phone radiation [radiofrequency electromagnetic waves (RF-EMW)] is extremely low compared to ionizing radiation, i.e., X-rays (frequency, 1010-1018 MHz), they do not cause ionization of molecule. However, exposure to RF-EMW causes a number of effects on biological systems. Recently, epidemiological studies, including one from our center, have proposed cell phone usage may adversely affect important parameters os sperm quality. Cell phone usage was associated with reduced sperm motility in men using their phone in excess of 4 hours a day vs. men without cell phone use. A cross-sectional study reported odds ratio (OR) of 1.86 for infertility among military personnel who self-reported exposure to RF-EMW relative to those who reported no work near RF-EMW field.
The mechanism of RF-EMW induced reproductive damage appears mulitfactorial. Chronic exposure affects the mitochondrial genome and nuclear β-globin locus of epididymal spermatozoa causing increased expression of adhesion protein on spermatozoa. Others have demonstrated a decrease in mean seminiferous tubule diameter after exposure of rats to cell phone radiation. Various animal studies have demonstrated induction of oxidative stress after cell phone exposure, suggesting stimulation of mammalian cell plasma membrane NADH oxidase with resulting free radical production.
In vitro studies of RF-EMW on human sperm are conflicting. One study showed decreased progressive sperm motility following exposure to cell phone radiation for 5 min on neat semen of human volunteers. Others showed no effect on purified mature spermatozoa following RF-EMW exposure for 1 h. We have recently demonstrated for the first time that RF-EMW exposure can cause oxidative stress in ejaculated human semen (RF-EMW exposure duration 1 h, specific absorbance rate (SAR) 1.46 W/ kg, temperature of 20 OC). We found significant increases in ROS levels and increased ROS/TAC scores after cell phone exposure.
The question of life style effects on semen quality has been debated extensively over the recent years. Conclusions remain elusive because lifestyle exposures are myriad, and it is difficult to adequately address all sperm parameters with a single lifestyle factor. In addition, the interaction of genetics, age and exposure duration is detrimental for the reproductive system damage. It is necessary to study the different age groups regarding the exposure to RF-EMW and its association with various other RF-EMW-related diseases. In vivo studies on healthy volunteers should be carried out to explore the RF-EMW effect on the reproductive health of men. Ultimately, future studies will help continue the evidence-based analysis of the impact of lifestyle factors on male fertility.
Written by:
Ashok Agarwal, PhD, Reda Z. Mahfouz, MD and Edmund Sabanegh, MD, as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
From: URO today
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