Sickle cell disease may affect brain function in adults

Sunday, 25 August 2013

Islamabad, Aug 26 (Newswire): Sickle cell disease may affect brain function in adults who have few or mild complications of the inherited blood disease, according to results of the first study to examine cognitive functioning in adults with sickle cell disease.

The multicenter study, funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, compared brain function scores and imaging tests in adult patients with few sickle cell complications with results in similar adults who did not have the blood disease.

Researchers report that the brain function scores in sickle cell patients were, on average, in the normal range. However, twice as many patients as healthy adults (33 percent versus 15 percent) scored below normal levels.

Those who were more likely to score lower were older and had the lowest levels of hemoglobin, the protein in red blood cells that carries oxygen in the blood, compared to sickle cell participants who scored higher. Findings from brain magnetic resonance imaging scans did not explain differences in scores.

Researchers at 12 sites within the NHLBI-supported Comprehensive Sickle Cell Centers conducted the study. Their results are published in the the Journal of the American Medical Association. An editorial accompanies the article.

"This study suggests that some adult patients who have sickle cell disease may develop cognitive problems, such as having difficulty organizing their thoughts, making decisions, or learning, even if they do not have severe complications such as stroke related to sickle cell disease," said NHLBI Acting Director Susan B. Shurin, M.D.

"Such challenges can tremendously affect a patient's quality of life, and we need to address these concerns as part of an overall approach to effectively managing sickle cell disease."

Researchers tested cognitive functioning of 149 adult sickle cell disease patients (between the ages of 19 and 55) and compared them to 47 healthy study participants of similar age and education levels from the same communities. All of the participants were African-American.

More sickle cell disease patients scored lower on measures such as intellectual ability, short-term memory, processing speed, and attention, than participants in the healthy group.

The sickle cell disease participants did not have a history of end-organ failure, stroke, high blood pressure, or other conditions that might otherwise affect brain function.

"We need to study whether existing therapies, such as blood transfusions, can help maintain brain function, or perhaps even reverse any loss of function," noted Elliott P. Vichinsky, M.D., of the Children's Hospital & Research Center Oakland, principal investigator of the study and the lead author of the paper.

"These effects were found in patients who have clinically mild sickle cell disease, which raises the question of whether therapies should be given to all patients to help prevent these problems from developing."

Researchers involved in this study are recruiting patients with sickle cell disease into a clinical trial to determine whether blood transfusions may help preserve cognitive function.

Participants will receive transfusions every three or four weeks for six months as part of the clinical study. Information about this study can be found at www.clinicaltrials.gov, search for NCT00850018.

Sickle cell disease affects about 70,000 Americans. At one time, many children died from the disease, but new therapies have enabled sickle cell disease patients to live well into middle age or beyond. As more people with sickle cell disease are living into adulthood, health care providers are uncovering previously unrecognized complications.

Studies of brain function in children who have sickle cell disease have suggested that some children with the disease, even if they have not suffered a stroke, have experienced silent brain injury. Others without obvious changes on brain scans may have some level of cognitive dysfunction that seems to worsen with age.

Stroke is a common complication of sickle cell disease, and can lead to learning disabilities, lasting brain damage, long-term disability, paralysis, or death.

Sickle cell disease involves an altered gene that produces abnormal hemoglobin. Red blood cells with sickle hemoglobin that have too little oxygen become C-shaped in addition to becoming stiff and sticky. These crescent-shaped cells can clump to block blood flow, causing severe pain and potential organ damage.
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Caffeine may slow Alzheimer's disease

Islamabad, Aug 26 (Newswire): Although caffeine is the most widely consumed psychoactive drug worldwide, its potential beneficial effect for maintenance of proper brain functioning has only recently begun to be adequately appreciated.

Substantial evidence from epidemiological studies and fundamental research in animal models suggests that caffeine may be protective against the cognitive decline seen in dementia and Alzheimer's disease (AD).

A special supplement to the Journal of Alzheimer's Disease, "Therapeutic Opportunities for Caffeine in Alzheimer's Disease and Other Neurodegenerative Diseases," sheds new light on this topic and presents key findings.

Guest editors Alexandre de Mendonça, Institute of Molecular Medicine and Faculty of Medicine, University of Lisbon, Portugal, and Rodrigo A. Cunha, Center for Neuroscience and Cell Biology of Coimbra and Faculty of Medicine, University of Coimbra, Portugal, have assembled a group of international experts to explore the effects of caffeine on the brain.

The resulting collection of original studies conveys multiple perspectives on topics ranging from molecular targets of caffeine, neurophysiological modifications and adaptations, to the potential mechanisms underlying the behavioural and neuroprotective actions of caffeine in distinct brain pathologies.

"Epidemiological studies first revealed an inverse association between the chronic consumption of caffeine and the incidence of Parkinson's disease," according to Mendonça and Cunha.

"This was paralleled by animal studies of Parkinson's disease showing that caffeine prevented motor deficits as well as neurodegeneration "Later a few epidemiological studies showed that the consumption of moderate amounts of caffeine was inversely associated with the cognitive decline associated with aging as well as the incidence of Alzheimer's disease.

Again, this was paralleled by animal studies showing that chronic caffeine administration prevented memory deterioration and neurodegeneration in animal models of aging and of Alzheimer's disease."
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Smallpox vaccine produces reduction in HIV replication

Islamabad, Aug 26 (Newswire): Vaccinia immunization, as given to prevent the spread of smallpox, produces a five-fold reduction in HIV replication in the laboratory.

Researchers writing in the open access journal BMC Immunology suggest that the end of smallpox vaccination in the mid-20th century may have caused a loss of protection that contributed to the rapid contemporary spread of HIV.

Raymond Weinstein, a family doctor turned laboratory scientist at George Mason University, Manassas, Virginia, worked with a team of researchers from George Washington University and UCLA.

The researchers looked at the ability of white blood cells taken from people recently immunized with vaccinia to support HIV replication compared to unvaccinated controls. They found significantly lower viral replication in blood cells from vaccinated individuals.

Weinstein said, "There have been several proposed explanations for the rapid spread of HIV in Africa, including wars, the reuse of unsterilized needles and the contamination of early batches of polio vaccine.

However, all of these have been either disproved or do not sufficiently explain the behaviour of the HIV pandemic. Our finding that prior immunization with vaccinia virus may provide an individual with some degree of protection to subsequent HIV infection suggests that the withdrawal of such vaccination may be a partial explanation."

Smallpox immunization was gradually withdrawn from the 1950s to the 1970s following the worldwide eradication of the disease, and HIV has been spreading exponentially since approximately the same time period.

Weinstein and his colleagues propose that vaccination may confer protection against HIV by producing long term alterations in the immune system, possibly including the expression of a certain receptor, CCR5, on the surface of a person's white blood cells which is exploited by both viruses.

Speaking about the results, Weinstein said, "While these results are very interesting and hopefully may lead to a new weapon against the HIV pandemic, they are very preliminary and it is far too soon to recommend the general use of vaccinia immunization for fighting HIV."
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