Risk Factors for Dementia
The "Mediterranean diet" may reduce the risk for developing Alzheimer's disease. Researchers in New York examined over 2000 subjects, interviewing them about dietary habits and testing their cognitive ability over time. Those who ate a Mediterranean diet--high in vegetables, grain, and unsaturated fats, and low in meat and dairy--were less likely to develop Alzheimer's disease.
Obesity in midlife may increase the risk of Alzheimer's disease, according to researchers in California. Health records from 1964 and the present were examined for almost 9,000 middle-aged individuals, correlating past obesity to the risk for a current diagnosis of Alzheimer's disease. Individuals in the top 20 percent of obesity measures in 1964 were two to three times as likely to develop Alzheimer's disease as those in the bottom 20 percent. Cognitive decline is also increased with lower blood levels of the hormone leptin, which affects both appetite and brain development. In a study of almost 3,000 healthy elderly followed over five years, those with the lowest leptin levels had a greater decline in their cognitive ability than those with the highest levels.
Sex hormones may also play a role in the risk for cognitive decline. In a study of almost 800 men and women, those women with the lowest levels of estradiol (a type of estrogen) declined fastest, compared to those women with the highest levels. This correlation was seen in both black and white women. No effect of estradiol was seen in men, and no effect was seen for the hormone testosterone in either sex.
Gambling in Parkinson's Disease
Parkinson's disease patients who gamble and take dopamine agonists to treat their symptoms are at higher risk for becoming compulsive gamblers, according to researchers from Canada. In a survey of over 180 patients, approximately 6 percent of those taking a dopamine agonist, either alone or in combination with levodopa (another symptomatic treatment), were compulsive gamblers, versus no patient on levodopa alone. Those who developed this compulsive behavior were all recreational gamblers before starting the dopamine agonist treatment.
Diet and exercise changes can help restore damaged skin nerves and reduce pain in patients with impaired glucose tolerance neuropathy (IGTN). This condition is often seen in patients who go on to develop diabetes. Diet and exercise changes have already been shown to help those with diabetes. In this study, 32 IGTN patients who underwent the same counseling as used in diabetes had improved stimulation of their skin and less pain, which correlated with improvements in glucose tolerance and reduced cholesterol.
Two studies highlighted advances in treatment of multiple sclerosis (MS). The experimental drug FTY720, derived from a Chinese herb and currently in clinical trials, demonstrated its ability to reduce lesions in the brain, and to reduce the number of relapses patients experience over the course of the year. Another study showed that natalizumab delays disease progression, reduces disability progression, and reduces brain lesions. Natalizumab is an antibody that was withdrawn from the market shortly after it was approved for treatment of MS. The Food and Drug Administration has recently lifted a clinical hold on the drug.
Stroke and Traumatic Brain Injury
Patients taking statins to lower their cholesterol have a reduced risk of stroke, according to an international study by researchers from Ohio and Korea. Those on statins had approximately half the risk of a first-ever stroke compared to those with equally high cholesterol but not on statins.
Pure oxygen does not help the brain recover after traumatic brain injury, according to researchers in Missouri. In a study of five patients, they found that 100 percent oxygen at normal pressure did not improve delivery of oxygen to the brain or increase metabolic activity. They noted that the utility of high-pressure (hyperbaric) oxygen is still unknown.
Experimental Treatments in ALS
Two experimental treatments in animal models of amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), may point the way to future clinical therapies of this disease. ALS destroys the nerve cells (neurons) in the brain and spinal cord that control muscles. A mutated enzyme called SOD1 has been shown to cause some cases of the disease. Researchers showed that by removing SOD1 not in neurons, but in neighboring cells called microglia, they could improve survival in a mouse model of the disease. Microglia may be much easier to target, or to replace, than neurons, making this finding potentially significant.
Antisense oligonucleotides stimulate the body's own cells to destroy selected genetic messages before they can become harmful. Researchers who used antisense oligonucleotides against SOD1 showed they could treat wide areas of the brain in both rats and monkeys, decreasing SOD1 and increasing survival. This therapeutic strategy may be useful against other targets in other neurodegenerative diseases as well, such as Huntington's disease and Alzheimer's disease.
Stem Cells for Nervous System Repair
Stem cells appear to be a promising source of new cells for repair of the nervous system, both in the brain and spinal cord. In an animal model, researchers showed that neural stem cells that expressed a cell survival factor called MEF2 could help repair the brain damage cause by stroke when injected into the site of the damage. Under the influence of MEF2, the stem cells transform into active nerve cells (neurons) after injection.
A substance derived from seaweed improves regrowth of damaged neurons and new stem cells in the spinal cord, according to research from Germany. The "anisotropic capillary hydrogel," has an internal structure that preferentially guides regrowing nerve cell extensions (axons) in one direction. Researchers showed that when it was implanted in an animal model of spinal cord injury, it improved regrowth of both existing neurons and implanted cells. Growth across a spinal cord injury is a significant barrier to recovery of nerve function, suggesting that this type of strategy may play a role in improving outcomes after these injuries.
The American Academy of Neurology, an association of more than 19,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer's disease, epilepsy, multiple sclerosis, Parkinson disease, and stroke.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
Published on PsychCentral.com. All rights reserved.