Fatty acid analysis of blood plasma of patients with alzheimer's disease, other types of dementia, and cognitive impairment

Abstract

Fatty acid differences, including docosahexaenoic acid (DHA; 22:6n-3) have been shown in the brains of Alzheimer's patients (AD) as compared with normal age-matched individuals. Furthermore, low serum DHA is a significant risk factor for the development of AD. The relative concentration of DHA and other fatty acids, however, in the plasma of AD patients compared with patients with other kinds of dementias (other dementias; OD), patients who are cognitively impaired but nondemented (CIND), or normal patients is not known. In this study we analyzed the total phospholipid, phosphatidylcholine (PC), phosphatidylethanolamine (PE), and lysophosphatidylcholine (lysoPC) fractions of plasma from patients diagnosed with AD, OD, or CIND and compared them with a group of elderly control subjects with normal cognitive functioning. Plasma phospholipid and PC levels of 20:5n-3, DHA, total n-3 fatty acids, and the n-3/n-6 ratio were lower in the AD, OD, and CIND groups. Plasma phospholipid 24:0 was lower in the AD, OD, and CIND groups as compared with the group of control patients, and total n-6 fatty acid levels were higher in the AD and CIND groups only. In the plasma PE fraction, levels of 20:5n-3, DHA, and the total n-3 fatty acid levels were significantly lower in the AD, OD, and CIND groups. DHA levels were lower in the lysoPC fraction of CIND individuals only. There were no other differences in the fatty acid compositions of the different phospholipid fractions. Therefore, in AD, OD, and CIND individuals, low levels of n-3 fatty acids in the plasma may be a risk factor for cognitive impairment and/or dementia. Interestingly, a decreased level of plasma DHA was not limited to the AD patients but appears to be common in cognitive impairment with aging.

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

“…With age, levels of DHA in rat and human brain have been reported to decrease in some but not all studies (Soderberg et al 1990;Lopez et al 1995;Favrelere et al 2000;Giusto et al 2002), and in humans, a low plasma DHA concentrations was associated with age-related cognitive impairment (Conquer et al 2000). One explanation for these observations is that the liver's capacity to synthesize DHA from its dietary available precursor α-LNA is reduced because of reduced activity of some enzymes involved in DHA biosynthesis (Horrobin 1981;Bordoni et al 1988;Bourre and Piciotti 1992).…”

Assessment of nutritional interventions for modification of age-associated cognitive decline using a canine model of human aging

“…A low intake of fish (Morris et al 2003), the major dietary source of DHA, and low serum DHA levels (Kyle et al 1999) are both linked to an increase in likelihood of developing Alzheimer's disease, whereas a high intake of fish is related to a decreased risk (Morris et al 2003). Similarly, Alzheimer's patients and humans with mild cognitive impairment have lower plasma levels of DHA and a larger n-6/n-3 fatty acid ratio (Conquer et al 2000). In Alzheimer's patients, cholestryl ester-DHA levels, a biomarker for DHA, is negatively correlated with the severity of dementia (Tully et al 2003).…”

Polyunsaturated fatty acids stimulate phosphatidylcholine synthesis in PC12 cells

“…The membrane phospholipids in brain contain high concentrations of the LCPUFA docosahexaenoic acid (DHA) [5], with highest levels observed in synaptic membranes [6,7], the growth cones of neurites [8,9] and rod outer segments of the retina [10,11]. Clinical and laboratory studies indicate that a number of neurodegenerative diseases involve cell membrane abnormalities which are associated with DHA deficiency [12][13][14][15], and that supplementation with DHA may offer protection against neuronal damage and cell death [16][17][18][19][20].…”