01 February 2013

Pig proteins may help dementia patients

A drug containing purified brain proteins derived from pigs may yield modest improvements in patients whose dementia is caused by a lack of blood flow to parts of the brain.


A drug containing purified brain proteins derived from pigs may yield modest improvements in patients whose dementia is caused by a lack of blood flow to parts of the brain, according to a new analysis.

Researchers in China pulled together results from six randomised controlled trials of Cerebrolysin and found that the drug slightly improved vascular dementia patients' scores on two tests that measure mental impairment.

"I think it shows a pathway that's worth pursuing and investigating - especially since there are no specific treatments for vascular dementia," said Dr Joe Verghese, professor of neurology and chief of the division of geriatrics at the Albert Einstein College of Medicine in New York.

But Verghese, who was not involved in the new analysis, told Reuters Health that he was not that impressed with the results, because the changes are so small that patients and their families wouldn't notice much of an improvement.

Vascular dementia is the second most common form of dementia - after Alzheimer's disease - in the western world.

How the study was done

Verghese said researchers first thought it was brought on by small strokes, but it's now believed that damage to tiny blood vessels - by conditions like high blood pressure and excess cholesterol - may also contribute to the condition.

People with vascular dementia can have memory and language problems, trouble walking and impaired motor skills, among other symptoms.

According to Verghese, some vascular dementia patients take Alzheimer's disease drugs, but the main treatment is to get a person's blood vessel-damaging risk factors under control.

Dr Li He, the study's senior author from West China Hospital in Chengdu, said people began experimenting with Cerebrolysin to treat brain disorders in the 1950s, but it did not become widely available until the 1980s.

The drug, which is not approved by the US Food and Drug Administration but is available in some 50 other countries, is a solution of small proteins and amino acids purified from pig brain tissues. The proteins are thought to act as nerve growth promoters and protectors of new nerve cells.

Trials around the world

Cerebrolysin is being studied in trials around the world for Alzheimer's disease, stroke, traumatic brain injuries and even infant brain damage due to oxygen deprivation.

The drug is delivered intravenously, typically over several days or weeks a few times per year, and costs approximately $400 (R3585) for a four-week cycle of 10 milliliters (ml) per day.

For their review of vascular dementia treatment with Cerebrolysin, He and his colleagues, who published their analysis in The Cochrane Library, searched for trials that compared the drug to other treatments or to no treatment. They found six qualifying studies conducted between 1991 and 2011 that included 597 participants.

Each trial was conducted differently. Doses ranged from 10ml of Cerebrolysin per day to 30ml per day. Three studies gave patients the drug for five days per week over four weeks while two administered the drug continuously for 15 to 28 days.

Patients’ health tracked post treatment

The studies also varied in how long they tracked patients' health after treatment - ranging from 15 days to three years. After adjusting for those differences, He's team found that overall, patients who got Cerebrolysin improved more than those in the comparison groups on two tests that measure mental function.

On a 30-point scale that tests thinking and learning skills, patients who got Cerebrolysin improved their scores by about one point more than patients in the comparison groups.

Cerebrolysin patients also improved by about four points more than those in the comparison groups on a 70-point Alzheimer's disease assessment scale that gauges mental impairment.

The single-point difference in the first test "is statistically significant, but it's not clinically meaningful," Verghese said. On the second test, the four-point difference is "barely what you would call clinically significant," he added.

But, Verghese noted, the researchers found there were few side effects from the medication. "This probably means it's worthwhile pursuing this medication in clinical trials, but I wouldn't change my practice based on this (study)," Verghese said.

In an email to Reuters Health, He agreed: "Cerebrolysin is indeed a promising agent for the treatment of (vascular dementia), but there is insufficient evidence to recommend Cerebrolysin as a routine therapy for such patients."

(Andrew M. Seaman, Reuters Health, February 2013)

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