New and Noteworthy Information—October 2015
Over the long term, a high dose of a purified form of resveratrol stabilizes a biomarker of Alzheimer’s disease progression, according to clinical trial results published online ahead of print September 11 in Neurology. Resveratrol is a naturally occurring compound found in foods such as red grapes, raspberries, dark chocolate, and some red wines. The randomized, phase II, placebo-controlled, double-blind study enrolled 119 patients with mild to moderate Alzheimer’s disease. The highest dose tested was 1 g orally twice per day. Patients who were treated with increasing doses of resveratrol over 12 months showed little or no change in amyloid-beta40 levels in blood and CSF. Those taking placebo had a decrease in the their levels of amyloid-beta40 over baseline. “We can’t conclude from this study that the effects of resveratrol treatment are beneficial,” said the investigators, but “it does appear that resveratrol was able to penetrate the blood–brain barrier, which is an important observation.”
Survivors of an intracerebral hemorrhage (ICH) who had inadequate blood pressure control during follow-up had a higher risk of ICH recurrence, according to a study in the September 1 issue of JAMA. This association was stronger with worsening severity of hypertension. Investigators studied 1,145 patients with ICH who survived at least 90 days. Median follow-up was 37 months. Blood pressure measurements were obtained at three, six, nine, and 12 months, and every six months thereafter. There were 102 recurrent ICH events among 505 survivors of lobar ICH and 44 recurrent ICH events among 640 survivors of nonlobar ICH. During follow-up, adequate blood pressure control was achieved on at least one measurement by 625 patients (55%) and consistently by 495 patients (43%). The ICH event rate for lobar and nonlobar ICH was higher among patients with inadequate blood pressure control, compared with patients with adequate blood pressure control.
Genetic findings support observational evidence that lower vitamin D levels are associated with increased risk of multiple sclerosis (MS), according to a study published online August 25 in PLOS Medicine. Using Mendelian randomization to reduce the possibility of confounding, the researchers examined whether there was an association between genetically reduced vitamin D levels and susceptibility to MS among participants in the International MS Genetics Consortium Study, which involves 14,498 patients with MS and 24,091 healthy controls. A genetic decrease in the natural-log-transformed vitamin D level by one standard deviation was associated with a twofold increased risk of MS. According to the researchers, “genetically lowered vitamin D levels are strongly associated with increased susceptibility to MS. Whether vitamin D sufficiency can delay or prevent MS onset merits further investigation.”
Diabetes may be linked to the buildup of tangles or tau in the brain, separate from Alzheimer’s disease, according to a study published online ahead of print September 2 in Neurology. The study involved 816 people (average age, 74). Of those, 397 had mild cognitive impairment, 191 had Alzheimer’s disease dementia, and 228 people had no memory or cognitive problems. A total of 124 people had diabetes. The researchers examined the relationship between type 2 diabetes, the loss of brain cells and their connections, levels of beta amyloid, and tau in the spinal fluid of the participants. Those with diabetes had on average 16 pg/mL greater levels of tau in the spinal and brain fluid, irrespective of the diagnosis of dementia. In addition, patients with diabetes had cortical tissue that was an average of 0.03 mm thinner than that of those who did not have diabetes, regardless of their cognitive abilities or dementia status.
Survivors of childhood cancer who have had a stroke have double the risk of a recurrent stroke when compared with noncancer stroke survivors, according to a study published online ahead of print August 26 in Neurology. The main predictors of recurrent stroke were cranial radiation therapy, hypertension, and older age at first stroke. Researchers analyzed retrospective data from the Childhood Cancer Survivor Study, which followed 14,358 survivors of pediatric cancer. Stroke rates were established through surveys and self-report. Of the 271 respondents who reported having a stroke, 70 also reported a second stroke. Overall, the rate of recurrence within the first 10 years after an initial stroke was 21%, which is double the rate in the general population of stroke survivors. The rate was 33% for patients who had received cranial radiation therapy.
—Glenn S. Williams
