Blood RNA concentration in Alzheimer disease and vascular dementia

Abstract

Background: To determine if blood RNA concentrations are altered in people with Alzheimer disease [AD] or vascular dementia [VaD]. Methods: Venous blood samples were collected from a population sample of 31 people aged 60+ years, living in an aged care residential centre, with AD or VaD, 20 randomly selected aged controls, living in the community, with normal cognition and no history of cerebrovascular disease and a convenience sample of 20 healthy young controls. Results: Total RNA was successfully extracted from the blood with the PAXGENE RNA system. There was a statistically significant difference in the blood RNA concentration between those with AD [n = 15, mean = 3.0 +/- 0.9], VaD [n = 15, mean = 3.7 +/- 1.4], young controls [n = 18, mean = 4.5 +/- 1.4] and aged controls [n = 19. mean = 5.0 +/- 1.1] [F= 9.05; p<0.0001], including when controlled for age [F=7.09, p<0.0001]. The RNA concentration in AD was statistically significantly lower than the aged controls [p<0.0001] and young controls [p=0.003]. RNA in VaD was statistically significantly lower than the aged controls [p=0.02]. Conclusion: As total blood RNA concentrations were lower in those with AD or VAD in this population based sample, further studies may be needed to ascertain the significance of this preliminary finding.