From Science Daily website (see original article)
Mar. 5, 2013 — Omega-3 fatty acids found in oily fish may have diverse health-promoting effects, potentially protecting the immune, nervous, and cardiovascular systems.
But how the health effects of one such fatty acid -- docosahexaenoic acid (DHA) -- works remains unclear, in part because its molecular signaling pathways are only now being understood.
Toshinori Hoshi, PhD, professor of Physiology, at the Perelman School of Medicine, University of Pennsylvania, and colleagues showed, in two papers out this week in the Proceedings of the National Academy of Sciences, how fish oils help lower blood pressure via vasodilation at ion channels.
In vascular smooth muscle cells, such as those that line blood vessels, ion channels that span the outer membrane of a cell to let such ions as sodium, calcium, and potassium in and out, are critical to maintaining proper vessel pressure.
The researchers found that DHA rapidly and reversibly activates these channels by increasing currents by up to 20 fold.
DHA lowers blood pressure in anesthetized wild type mice but not in mice genetically engineered without a specific ion channel subunit.
In comparison, the team found that a dietary supplement, DHA ethyl ester, found in most fish oil pills fails to activate the same channels, and even antagonizes the positive effect of DHA from natural sources, on the cells.
The DHA ethyl ester seems to compete with the natural form of DHA for binding sites on the ion channel.
The team concluded that these channels have receptors for long-chain omega-3 fatty acids, and that DHA -- unlike its ethyl ester cousin -- activate the channels and lower blood pressure.
The findings have practical implications for the use of omega-3 fatty acids as nutraceuticals for the general public and also for critically ill patients who may receive omega-3-enriched formulas as part of their nutrition.
Coauthor Michael Bauer from Jena University Hospital in Germany, who studies sepsis in a clinical setting, says the findings may encourage physicians to have a closer look at the specific formulations given to sepsis patients as they may contain either the free omega-3 acid or the ester.
The findings also underscore the importance of obtaining omega-3 fatty acids from natural food sources such as oily fish.
giovedì 11 aprile 2013
domenica 7 aprile 2013
Low Testosterone Levels May Herald Rheumatoid Arthritis in Men
From Science Daily website (see original article)
Apr. 3, 2013 — Low testosterone levels may herald the subsequent development of rheumatoid arthritis in men, suggests research published online in the Annals of the Rheumatic Diseases.
Sex hormones are thought to play a part in the development of rheumatoid arthritis, and both men and women with the condition tend to have lower levels of testosterone in their blood than healthy people.
But it is not clear whether this is a contributory factor or a consequence of the disease.
The researchers based their findings on participants of the Swedish Malmo Preventive Medicine Program (MPMP), which began in 1974 and tracked the health of more than 33,000 people born between 1921 and 1949.
As part of their inclusion in the Program, participants were subjected to a battery of tests, completed a questionnaire on health and lifestyle factors, and left blood samples after an overnight fast.
The authors identified all those MPMP participants who were subsequently diagnosed with rheumatoid arthritis up to December 2004 by cross checking national and regional registers.
Stored blood samples were available for 104 of the men who subsequently developed rheumatoid arthritis, and for 174 men of the same age who did not develop the disease.
The average period of time that elapsed between donating the blood sample and a diagnosis of rheumatoid arthritis was just under 13 years, but ranged from one to 28.
Rheumatoid factor status was known at diagnosis for 83 of the men, almost three out of four (73%) of whom tested positive for it; the rest tested negative. Rheumatoid factor is an antibody that indicates disease severity and is used to categorise the condition.
After taking account of smoking and body mass index, both of which can affect the risk of rheumatoid arthritis, men with lower levels of testosterone in their blood samples were more likely to develop the disease.
This was statistically significant for those who tested negative for rheumatoid factor when they were diagnosed.
These men also had significantly higher levels of follicle stimulating hormone -- a chemical that is involved in sexual maturity and reproduction -- before they were diagnosed with rheumatoid arthritis.
This is likely to be secondary to reduced testosterone production, say the authors.
The findings prompt them to suggest that hormonal changes precede the onset of rheumatoid arthritis and could influence disease severity.
They point to other studies, which indicate that testosterone may dampen down the immune system, so quelling inflammation. Rheumatoid arthritis is also more likely to go into remission in its early stages in men, they say.
Apr. 3, 2013 — Low testosterone levels may herald the subsequent development of rheumatoid arthritis in men, suggests research published online in the Annals of the Rheumatic Diseases.
Sex hormones are thought to play a part in the development of rheumatoid arthritis, and both men and women with the condition tend to have lower levels of testosterone in their blood than healthy people.
But it is not clear whether this is a contributory factor or a consequence of the disease.
The researchers based their findings on participants of the Swedish Malmo Preventive Medicine Program (MPMP), which began in 1974 and tracked the health of more than 33,000 people born between 1921 and 1949.
As part of their inclusion in the Program, participants were subjected to a battery of tests, completed a questionnaire on health and lifestyle factors, and left blood samples after an overnight fast.
The authors identified all those MPMP participants who were subsequently diagnosed with rheumatoid arthritis up to December 2004 by cross checking national and regional registers.
Stored blood samples were available for 104 of the men who subsequently developed rheumatoid arthritis, and for 174 men of the same age who did not develop the disease.
The average period of time that elapsed between donating the blood sample and a diagnosis of rheumatoid arthritis was just under 13 years, but ranged from one to 28.
Rheumatoid factor status was known at diagnosis for 83 of the men, almost three out of four (73%) of whom tested positive for it; the rest tested negative. Rheumatoid factor is an antibody that indicates disease severity and is used to categorise the condition.
After taking account of smoking and body mass index, both of which can affect the risk of rheumatoid arthritis, men with lower levels of testosterone in their blood samples were more likely to develop the disease.
This was statistically significant for those who tested negative for rheumatoid factor when they were diagnosed.
These men also had significantly higher levels of follicle stimulating hormone -- a chemical that is involved in sexual maturity and reproduction -- before they were diagnosed with rheumatoid arthritis.
This is likely to be secondary to reduced testosterone production, say the authors.
The findings prompt them to suggest that hormonal changes precede the onset of rheumatoid arthritis and could influence disease severity.
They point to other studies, which indicate that testosterone may dampen down the immune system, so quelling inflammation. Rheumatoid arthritis is also more likely to go into remission in its early stages in men, they say.
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