New and Noteworthy Information—February 2016
For every hour of reperfusion delay, the benefit of intra-arterial treatment for ischemic stroke decreases and the absolute risk difference for a good outcome is reduced by 6%, according to a study published online ahead of print December 21, 2015, in JAMA Neurology. The Multicenter Randomized Clinical Trial of Endovascular Treatment of Acute Ischemic Stroke in the Netherlands (MR CLEAN) compared intra-arterial treatment with no intra-arterial treatment in 500 patients. The median time to treatment was 260 minutes. Median time from treatment to reperfusion was 340 minutes. The researchers found an interaction between time from treatment to reperfusion and treatment effect, but not between time to treatment and treatment effect. The adjusted risk difference was 25.9% when reperfusion was achieved at three hours, 18.8% at four hours, and 6.7% at six hours.
Anticholinergic drugs are not associated with impaired cognitive performance among patients with Parkinson’s disease, according to a study published October 2, 2015, in Journal of Parkinson’s Disease. Using data from the Incidence of Cognitive Impairment in Cohorts with Longitudinal Evaluation—Parkinson’s Disease study, the researchers studied 195 patients with Parkinson’s disease and 84 controls. Patients’ detailed medication history, including over-the-counter drugs, was evaluated using the Anticholinergic Drug Scale (ADS). Each drug’s anticholinergic activity was classified on a scale from 0 to 3. Follow-up lasted 18 months. The investigators found no differences in global cognition, attention, memory, or executive function between patients with Parkinson’s disease who used anticholinergic drugs and those who did not. The proportion of patients with mild cognitive impairment was similar in both groups.
Anxiety symptoms are associated with an increased risk of dementia, according to a study published online ahead of print November 6, 2015, in Alzheimer’s & Dementia. The study included 1,082 fraternal and identical twins without dementia. Participants completed an assessment of anxiety symptoms in 1984 and were followed for 28 years. The twins also completed in-person tests every three years, answered questionnaires, and were screened for dementia throughout the study. Baseline anxiety score, independent of depressive symptoms, was significantly associated with incident dementia over follow-up. There was a 48% increased risk of dementia for people who had experienced high anxiety at any time, compared with those who had not. In co-twin analyses, the association between anxiety symptoms and dementia was greater for dizygotic, compared with monozygotic twins.
Common variants of MS4A6A and ABCA7 are associated with atrophy in cortical and hippocampal regions of the brain, according to a study published online ahead of print November 5, 2015, in Neurobiology of Aging. Researchers studied the relationship between the top 10 genetic variants associated with Alzheimer’s disease risk, excluding APOE, with cortical and hippocampal atrophy. They performed 1.5-T MRI to measure brain size and conducted genetic analyses for 50 cognitively normal participants and 98 participants with mild cognitive impairment. After explicit matching of cortical and hippocampal morphology, investigators computed in 3D the cortical thickness and hippocampal radial distance measures for each participant. MS4A6A rs610932 and ABCA7 rs3764650 had significant associations with cortical and hippocampal atrophy. The study may be the first to report the effect of these variants on neurodegeneration.
Anemia is associated with an increased risk of mild cognitive impairment (MCI), independent of traditional cardiovascular risk factors, according to a study published November 21, 2015, in Journal of Alzheimer’s Disease. Researchers examined 4,033 participants in a cohort study with available hemoglobin data and complete cognitive assessments. Participants’ age ranged between 50 and 80, and they were assessed between 2000 and 2003. Participants with anemia (ie, hemoglobin level less than 13 g/dl in men and less than 12 g/dl in women) had poorer cognitive performance in verbal memory and executive function, compared with people without anemia. The fully adjusted odds ratios for MCI, amnestic MCI, and nonamnestic MCI in anemic versus nonanemic participants were 1.92, 1.96, and 1.88, respectively.
By manipulating the WNT pathway, researchers efficiently differentiated human pluripotent stem cells to cells resembling central serotonin neurons, according to a study published in the January issue of Nature Biotechnology. For their investigation, the researchers used stem cells derived from embryos and stem cells derived from adult cells. The resulting serotonin neurons resembled those located in the rhombomeric segments 2-3 of the rostral raphe. They expressed a series of molecules essential for serotonergic development, including tryptophan hydroxylase 2. The cells also exhibited typical electrophysiologic properties and released serotonin in an activity-dependent manner. When treated with tramadol and escitalopram oxalate, the serotonin neurons released or took up serotonin in a dose- and time-dependent manner. These cells may help researchers to evaluate drug candidates, according to the investigators.
