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Promising Results for New Alzheimer’s Therapy
Scientists at the Karolinska Institute in Sweden have evaluated a new therapy for Alzheimer’s disease (AD) in which the patients receive an implant that stimulates the growth of a certain type of nerve cell. The results, published online in Alzheimer’s & Dementia, suggest that the introduction of a nerve growth factor (NGF) can prevent neuronal degradation in AD patients.
Patients with AD experience a selective and early breakdown of cholinergic nerve cells, which require a specific NGF –– essentially a group of proteins necessary for cell growth and survival –– to function. As NGF levels decline, the cholinergic nerve cells begin to degrade, and the patient’s condition slowly deteriorates.
In an attempt to curb the breakdown of cholinergic nerve cells, the researchers introduced NGF directly into the brains of six AD patients. To do this, they used NGF-producing cell capsules, placing them in the basal fore-brain, where the cholinergic cells are located, using precision stereotactic surgery. There, the capsules, which can easily be removed, release NGF to the surrounding cells to prevent their degradation.
To gauge whether the release of NGF had an effect on the cholinergic nerve cells, the researchers assayed the presence of specific markers of functioning cholinergic cells. This cell system communicates using acetylcholine, which in turn produces an enzyme called ChAT, which is found both inside and outside the cells. The researchers therefore developed a method that allowed them to measure ChAT in the cerebral spinal fluid for the first time.
“Our results show that when the patients received NGF, there was a significant increase in ChAT in the CSF,” said Dr. Taher Darreh-Shori, one of the researchers involved in the study. “The patients that exhibited this increase were also those that responded best to the treatment. Our PET [positron emission tomography] scans also showed an increase in cholinergic cell activity and metabolism in the brain.”
In addition, the researchers were able to detect a retardation of memory impairment over time compared with untreated patients.
“The results are promising, but must be treated with circumspection as only a few patients participated in the study,” said principal investigator Professor Maria Eriksdotter. “So our findings will have to be substantiated in a larger controlled study using more patients.”
Sources: Karolinska Institute; February 13, 2015; and Alzheimer’s & Dementia; February 9, 2015.