Environmental organochlorines and semen quality: results of a pilot study.

There have been numerous studies that suggest that sperm concentrations (sperm counts) are declining in men. However, other studies suggest that sperm counts are not declining or may be increasing in some areas. Although there is disagreement on whether there is a downward temporal trend in sperm counts, the studies provide evidence that sperm counts vary by geographic location. It has been hypothesized that the geographic variation in sperm concentrations may be due to environmental exposures, lifestyle factors, or some unknown causes. To determine whether contemporary ambient levels of polychlorinated biphenyls (PCBs) and p,p-DDE are associated with altered semen quantity and quality, we selected a study population without specific exposure to PCBs or p,p-DDE. The present study presents the results from a pilot study on the relationship between serum PCBs and p,p-DDE and semen quality in 29 subjects recruited from the Massachusetts General Hospital Andrology Laboratory. Of the 29 subjects, 3 had sperm concentrations < 20 million/mL, 7 had < 50% motile sperm, 9 had < 4% normal morphology, and 6 were below normal in more than one semen parameter. The 18 subjects with normal spermatozoa concentration, motility, and morphology were used as comparison subjects. The mean (SE) concentration of the sum of PCBs and p,p-DDE was 242 ng/g lipids (34.0) and 354 ng/g lipids (120), respectively, for men with below normal motility as compared to 202 ng/g lipids (16.6) and 240 ng/g lipids (31.1), respectively, for the comparison subjects. The data showed general trends that were suggestive of an association between PCBs and p,p-DDE and abnormal motility, as well as with sperm concentration and morphology. A full-scale study is currently in progress

Environmental Organochlorines and Semen Quality: Results of a Pilot Study

There have been numerous studies that suggest that sperm concentrations (sperm counts) are declining in men. However, other studies suggest that sperm counts are not declining or may be increasing in some areas. Although there is disagreement on whether there is a downward temporal trend in sperm counts, the studies provide evidence that sperm counts vary by geographic location. It has been hypothesized that the geographic variation in sperm concentrations may be due to environmental exposures, lifestyle factors, or some unknown causes. To determine whether contemporary ambient levels of polychlorinated biphenyls (PCBs) and p,p'-DDE are associated with altered semen quantity and quality, we selected a study population without specific exposure to PCBs or p,p'-DDE. The present study presents the results from a pilot study on the relationship between serum PCBs and p,p'-DDE and semen quality in 29 subjects recruited from the Massachusetts General Hospital Andrology Laboratory. Of the 29 subjects, 3 had sperm concentrations < 20 million/mL, 7 had < 50% motile sperm, 9 had < 4% normal morphology, and 6 were below normal in more than one semen parameter. The 18 subjects with normal spermatozoa concentration, motility, and morphology were used as comparison subjects. The mean (SE) concentration of the sum of PCBs and p,p'-DDE was 242 ng/g lipids (34.0) and 354 ng/g lipids (120), respectively, for men with below normal motility as compared to 202 ng/g lipids (16.6) and 240 ng/g lipids (31.1), respectively, for the comparison subjects. The data showed general trends that were suggestive of an association between PCBs and p,p'-DDE and abnormal motility, as well as with sperm concentration and morphology. A full-scale study is currently in progress

Impact of seasonal variation, age and smoking status on human semen parameters: The Massachusetts General Hospital experience

BACKGROUND: To investigate the relationship of human semen parameters with season, age and smoking status. METHODS: The present study used data from subjects recruited into an ongoing cross-sectional study on the relationship between environmental agents and semen characteristics. Our population consisted of 306 patients who presented to the Vincent Memorial Andrology Laboratory of Massachusetts General Hospital for semen evaluation. Sperm concentration and motility were measured with computer aided sperm analysis (CASA). Sperm morphology was scored using Tygerberg Kruger strict criteria. Regression analyses were used to investigate the relationships between semen parameters and season, age and smoking status, adjusting for abstinence interval. RESULTS: Sperm concentration in the spring was significantly higher than in winter, fall and summer (p < 0.05). There was suggestive evidence of higher sperm motility and percent of sperm with normal morphology in the spring than in the other seasons. There were no statistically significant relationships between semen parameters and smoking status, though current smokers tended to have lower sperm concentration. We also did not find a statistically significant relationship between age and semen parameters. CONCLUSIONS: We found seasonal variations in sperm concentration and suggestive evidence of seasonal variation in sperm motility and percent sperm with normal morphology. Although smoking status was not a significant predictor of semen parameters, this may have been due to the small number of current smokers in the study

The effects of nicotinamide riboside on postprandial oxidative stress and vascular function

High-fat meal (HFM) consumption increases oxidative stress in humans. The metabolic cofactor nicotinamide adenine dinucleotide (NAD+), has been identified as a key regulator of oxidative stress. Older individuals suffer from low NAD+ levels and experience age-related increases in oxidative stress. Nicotinamide Riboside (NR), a newly discovered NAD+ precursor has demonstrated the ability to raise NAD+ in older adults. Nicotinic Acid (NA), another NAD+ precursor is established as one of the oldest anti-atherogenic supplements that improves vascular function. Similarities between NR and NA indicate NR may have potential vascular benefits yet to be discovered. We hypothesized that one week of NR supplementation would reduce postprandial oxidative stress and improve vascular function following consumption of a HFM (1050 kcal, 72g fat) in old and young participants. We performed a double-blind, placebo-controlled crossover study with 16 participants, divided into young (n=13) and old (n=3) groups, assessing one week of 250mg 2x/day NR on a lipid peroxidation indicator of oxidative stress. Microvascular function was determined with blood flow measurements of post occlusive reactive hyperemia (PORH), analyzed using laser speckle contrast imaging (LSCI). NR supplementation did not significantly affect levels of postprandial lipid peroxidation indicators of oxidative stress (MDA). No differences in postprandial PORH measures of microvascular function were identified for treatment, time and interaction. Plasma MDA, glucose, and triglycerides all increased postprandially with significantly higher levels reported in the old group compared to young (p<0.001, p=0.04, p<0.001, respectively). One week of NR supplementation was well tolerated in all participants but had no effect on postprandial oxidative stress and microvascular function.</p

The effects of nicotinamide riboside on postprandial oxidative stress and vascular function

High-fat meal (HFM) consumption increases oxidative stress in humans. The metabolic cofactor nicotinamide adenine dinucleotide (NAD+), has been identified as a key regulator of oxidative stress. Older individuals suffer from low NAD+ levels and experience age-related increases in oxidative stress. Nicotinamide Riboside (NR), a newly discovered NAD+ precursor has demonstrated the ability to raise NAD+ in older adults. Nicotinic Acid (NA), another NAD+ precursor is established as one of the oldest anti-atherogenic supplements that improves vascular function. Similarities between NR and NA indicate NR may have potential vascular benefits yet to be discovered. We hypothesized that one week of NR supplementation would reduce postprandial oxidative stress and improve vascular function following consumption of a HFM (1050 kcal, 72g fat) in old and young participants. We performed a double-blind, placebo-controlled crossover study with 16 participants, divided into young (n=13) and old (n=3) groups, assessing one week of 250mg 2x/day NR on a lipid peroxidation indicator of oxidative stress. Microvascular function was determined with blood flow measurements of post occlusive reactive hyperemia (PORH), analyzed using laser speckle contrast imaging (LSCI). NR supplementation did not significantly affect levels of postprandial lipid peroxidation indicators of oxidative stress (MDA). No differences in postprandial PORH measures of microvascular function were identified for treatment, time and interaction. Plasma MDA, glucose, and triglycerides all increased postprandially with significantly higher levels reported in the old group compared to young (p\u3c0.001, p=0.04, p\u3c0.001, respectively). One week of NR supplementation was well tolerated in all participants but had no effect on postprandial oxidative stress and microvascular function