High Levels of Urinary Paracetamol May Impair Male Fertility, Study Suggests
Couples in which the male partner had high levels of paracetamol in his urine took longer to achieve pregnancy than couples in which the male had lower levels of the compound, according to a preliminary study by researchers at NIH.
Paracetamol, also known as acetaminophen, is a non-prescription drug widely used as a pain reliever and fever reducer. It also is one of the compounds produced when the body breaks down aniline, a chemical used to make rubber, pesticides and coloring agents used in food, cosmetics and clothing. The study was published online in Human Reproduction.
“At this point, our findings need to be corroborated by future research, and there is no cause for alarm,” said Dr. Melissa Smarr, the study’s first author, a postdoctoral fellow in the Division of Intramural Population Health Research at NICHD.
Smarr explained that the high levels of paracetamol in the urine of certain men in the study were unlikely to result only from taking medications and were more consistent with those seen from environmental exposure, either to aniline or paracetamol or a combination of the two. The findings could have implications for the amount of paracetamol exposure that is considered acceptable.
The authors stressed that their findings need to be confirmed by larger studies that can better identify the sources of paracetamol, the duration of time the participants are exposed and the amount of the compound to which they are exposed.
Researchers Make Advance in Possible Treatments for Gaucher, Parkinson’s Diseases
With assistance from high-throughput drug screening, NIH researchers have identified and tested a molecule that shows promise as a possible treatment for the rare Gaucher disease and the more common Parkinson’s disease. Dr. Ellen Sidransky, a senior investigator with NHGRI, and her collaborators at NINDS and NCATS published their findings June 12 in the Journal of Neuroscience.
“Until now, drugs used to treat Gaucher disease have not been able to enter the brain and reach those neurons that are affected in the most severe forms of Gaucher disease or in Parkinson’s disease,” said Sidransky. “It’s really exciting to have found a molecule that theoretically could be widely available to treat people with these diseases. However, there’s a long distance between identifying this molecule and having an approved drug.”
Sidransky has conducted research on Gaucher disease for the last 28 years and made the connection between Gaucher disease and Parkinson’s disease in 2001.
“This research constitutes a major advance,” said Dr. Daniel Kastner, NHGRI scientific director. “It demonstrates how insights from a rare disorder such as Gaucher disease can have direct relevance to the treatment of common disorders like Parkinson’s disease.”
Researchers will next test the new molecule to see if it might be developed into an appropriate prototype drug for patients with Gaucher disease and Parkinson’s disease.
Gaucher disease affects an estimated 1 in 50,000 to 1 in 100,000 people in the general population. People of Eastern and Central European (Ashkenazi) Jewish heritage are more likely to get Gaucher disease. Parkinson’s disease affects 1.5-2 percent of people over age 60, and the incidence increases with age. In the United States, about 60,000 new cases are identified each year. Parkinson’s disease affects more than 1 million people in North America and 7 million-10 million people worldwide.
Visual Activity Regenerates Neural Connections Between Eye, Brain
An NIH-funded study in mice shows for the first time that high-contrast visual stimulation can help damaged retinal neurons regrow optic nerve fibers, otherwise known as retinal ganglion cell axons. In combination with chemically induced neural stimulation, axons grew further than in strategies tried previously. Treated mice partially regained visual function. The study also demonstrates that adult regenerated central nervous system (CNS) axons are capable of navigating to correct targets in the brain. The research was funded through the National Eye Institute.
“Reconnecting neurons in the visual system is one of the biggest challenges to developing regenerative therapies for blinding eye diseases like glaucoma,” said NEI director Dr. Paul Sieving. “This research shows that mammals have a greater capacity for central nervous system regeneration than previously known.”
The researchers induced optic nerve damage in mice behind one eyeball. The mice were then placed in a chamber several hours a day for 3 weeks where they viewed high-contrast images—essentially changing patterns of black lines. The mice had modest but significant axonal regrowth compared to control mice that did not receive the high-contrast visual stimulation.
“We saw the most remarkable growth when we closed the good eye, forcing the mice to look through the injured eye,” said Dr. Andrew Huberman of Stanford University School of Medicine’s department of neurobiology, lead author of the report published online July 11 in Nature Neuroscience. In 3 weeks, the axons grew as much as 12 millimeters, a rate about 500 times faster than untreated CNS axons.
The regenerating axons also navigated to the correct brain regions, a finding that Huberman said sheds light on a pivotal question in regenerative medicine: “If a nerve cell can regenerate, does it wander or does it recapitulate its developmental program and find its way back to the correct brain areas?”