Gas chromatography–mass spectrometry analysis of the free fatty acids in serum obtained from patients with Alzheimer’s disease1

Abstract

Abstract. As the worldwide elderly population has grown, the incidence and prevalence of Alzheimer's disease (AD) has steadily increased. The differential lifelong exposure of populations to dietary fatty acids has raised concerns about the potential links between cognitive impairments and nutrition. However, few studies have addressed the levels of free fatty acids (FFAs) in AD patient serum. In this study, gas chromatography-mass spectrometry (GC-MS) was used to determine the levels of 15 serum FFAs in 31 AD patients and 33 healthy controls. The optimized methodology entailed the formation of methyl esters using 10% v/v H 2 SO 4 /CH3OH at 62°C for 2 hours. The linear range was 0.55-300 ȝg/mL, the range of recovery was 85.1-104.3%, and the detection limit was 0.03-0.08 ȝg/mL. Several FFAs in the AD patient significantly decreased when compared to the control, including three saturated fatty acids (C14:0, C16:0, and C18:0) and six unsaturated fatty acids (C16:1, C18:1, C18:2, Ȗ-C18:3, C20:2, and C22:6). The serum level of C18:3 was significantly higher in the AD patients. The FFA profiles of the AD patients differed significantly from those of controls. The method effectively determined the FFA levels and could facilitate future studies regarding the relationship between AD and the metabolism of FFAs.

Mass spectrometric analysis of free fatty acids in infant milk powders by frozen pretreatment coupled with isotope‐labeling derivatization

“…To demonstrate the advantages of the DMPP derivatization method, a comparative study with previously reported methods was established in terms of derivatization conditions, separation capacity, injection time, and detection limits. For methyl esterification, a common derivatization method for FFAs, the GC–MS analysis was time consuming (44 min) and the LOD (0.03–0.08 μg/mL) was much higher than DMPP derivatization (0.86–4.54 pg/mL) . After optimization, the methyl esterification method coupled with ionic liquid was established for the determination of fatty acids, but unfortunately this method was also time consuming (45 min) and the separation capacity was poor .…”

A metalloproteomic analysis of interactions between plasma proteins and zinc: elevated fatty acid levels affect zinc distribution

“…From this, we infer that the decreased Zn 2+ binding capacity of albumin in the presence of FFAs may have significant implications, for both normal and disease-altered physiology. Whilst numerous pathological diseases are associated with elevated levels of free fatty acids, not limited to cardiovascular diseases (including thrombosis), [114][115][116] diabetes, [117][118][119] and neurodegenerative diseases, [120][121][122] FFA levels also fluctuate during periods of intense exercise, fasting and after the consumption of food. [123][124][125] A deeper understanding of the downstream consequences of FFA-mediated Zn 2+ re-distribution is now required to comprehend the wider impact this may have on organismal physiology.…”

Lipidomics of Bioactive Lipids in Alzheimer’s and Parkinson’s Diseases: Where Are We?

“…A more complete study analyzed the level of FFAs in the serum of AD patients and found that several of them significantly decreased when compared to the control; the study included 3 saturated fatty acids (C14:0, C16:0, and C18:0) and 6 unsaturated fatty acids (C16:1, C18:1, C18:2, γ-C18:3, C20:2, and C22:6). The serum level of C18:3 was significantly higher in AD patients [ 30 ]. In an elegant study by Martin et al, lipid composition was analyzed in lipid rafts of human frontal brain cortex obtained between 3- and 18-h post-mortem, revealing that lipid rafts from AD brains exhibit aberrant lipid profiles compared to healthy brains.…”