Men with diabetes in midlife have an increased risk for Alzheimer’s disease, researchers reported in the April 9 online Neurology. Acute insulin response and glucose tolerance were tested among 2,322 50-year-old men. During a median 32-year follow-up, 102 participants were diagnosed with Alzheimer’s disease, 57 with vascular dementia, and 394 with any dementia or cognitive impairment. The researchers found that patients with a low insulin response at baseline had a higher cumulative risk of Alzheimer’s disease (hazard ratio [HR] per 1-SD decrease, 1.31). The association was stronger in participants without the apolipoprotein ε4 allele. Impaired glucose tolerance increased the risk of vascular dementia (HR per 1-SD decrease, 1.45). “Impaired insulin secretion, glucose intolerance, and estimates of insulin resistance were all associated with higher risk of any dementia and cognitive impairment,” added the study authors.
High blood pressure may prevent the onset of headaches, reported researchers in the April 15 Neurology. According to an analysis of data from the large epidemiologic Nord-Trøndelag Health Survey from 1984-1986 and 1995-1997, increasing systolic blood pressure and pulse pressure were both associated with decreasing prevalence of nonmigrainous headache or migraine. The findings were less clear in patients using antihypertensive medication, however. The researchers observed that both increases are related to arterial stiffness and that headache prevalence may be decreased through modulation of the baroreflex arch. “Stimulation of the baroreflex arch in response to increased blood pressure is assumed to inhibit pain transmission at both spinal and supraspinal levels, possibly because of an interaction of the centers modulating nociception and cardiovascular reflexes in the brainstem,” they concluded.
Chronic ingestion of caffeine protects the blood-brain barrier from cholesterol-induced leakage, according to a study in the April Journal of Neuroinflammation. Researchers fed rabbits a 2% cholesterol-enriched diet and administered 3 mg of caffeine daily in the drinking water for 12 weeks. “Caffeine blocked high cholesterol diet-induced increases in extravasation of immunoglobulin G and fibrinogen, increases in leakage of Evan’s blue dye, decreases in levels of the tight junction proteins occludin and zona occludens 1, increases in astrocytes activation, and microglia density where immunoglobulin G extravasation was present,” said the authors. Because high cholesterol is a risk factor for Alzheimer’s disease, they suggested that caffeine and caffeine-like drugs could be useful in its treatment.
A new nano-engineered gel inhibits formation of scar tissue and enables fiber to regenerate and grow after a spinal cord injury, reported researchers in the April 2 Journal of Neuroscience. Peptide amphiphile molecules self-assemble in vivo to form cylindrical nanofibers that display the laminin epitope IKVAV, and the resultant nanofibers have been observed to promote neurite outgrowth from cultured neurons. In the present study, mice treated with peptide amphiphile molecules showed reduced astrogliosis, reduced cell death, and an increased number of oligodendroglia at the site of injury. In addition, the nanofibers promoted regeneration of descending motor fibers and ascending sensory fibers through the lesion site, and significant behavioral improvement was observed, said the researchers.
The increase in autism rates may be attributed to changing diagnostic criteria, according to a study published in the May Developmental Medicine and Child Neurology. Among 38 adults ages 15 to 31 (31 men) who had participated in studies of developmental language disorder during childhood, self-completion of the Autism Diagnostic Observation Schedule–Generic and parent evaluations on the Autism Diagnostic Interview–Revised (based on symptoms present at ages 4 to 5) revealed that eight individuals met criteria for autism and four met criteria for milder forms of autistic spectrum disorder. “Most individuals with autism had been identified with pragmatic impairments in childhood,” said the study authors. They asserted that children who are now diagnosed unambiguously with autistic disorder previously would have been diagnosed with developmental language disorder.
Leaky blood vessels that no longer have the ability to protect the spinal cord from toxins may contribute to the development of amyotrophic lateral sclerosis, as reported in the April Nature Neuroscience. Researchers found that mice with a superoxide dismutase 1 mutation had disruption of the blood–spinal cord barrier and reduced levels of tight junction proteins zona occludens 1, occludin, and claudin 5 between endothelial cells. This resulted in microhemorrhages with release of neurotoxic hemoglobin-derived products, reductions in microcirculation, and hypoperfusion. The damage accumulated before motor neuron degeneration and the neurovascular inflammatory response occurred, however, “indicating that it was a central contributor to disease initiation,” said the authors.
Race and community factors affect the rate of stroke hospitalization among Medicare beneficiaries, according to a report by the CDC and the Centers for Medicare and Medicaid Services. The study showed that the stroke hospitalization rate for African Americans was 27% higher than for the general population, 30% higher than for whites, and 36% higher than for Hispanics. Community conditions, including the availability of affordable healthy food, safe options for physical activity, access to high-quality health care, and antismoking legislation and policies, can influence a person’s risk for stroke, the investigators pointed out. They also reported that counties in the southeastern states had the highest rate of stroke hospitalizations, and 21% of counties did not have a hospital at all, 31% lacked a hospital with an emergency department, and 77% did not have a hospital with neurology services. The study may facilitate quality initiatives and payment reform proposals to address the variations identified and focus more attention on the needs of underserved Medicare populations, noted the authors.