Fatty Acid Composition of Plasma Phosphatidylcholine Determines Body Fat Parameters in Subjects with Metabolic Syndrome-Related Traits.

Key Findings

Incidence of MetS, which is characterized  by  significant insulin resistance, is mostly connected with increased proportions of serum-saturated FA (SFA), palmitoleic acid (POA),   and  dihomo-y-linolenic   (DGLA)   acid, whereas proportions of linoleic acid (LA) and total n-6 FAs are decreased. Increased estimated activities are usually found for the enzymes delta-9 desaturase (D9D) and

delta-6 desaturase (D6D), which catalyze the synthesis of POA from palmitic acid (PA), oleic acid (OA) from stearic acid (SA), and y-linolenic (GLA) acid from LA. The activity of D5D, which catalyzes the synthesis of arachidonic acid (AA, 20:4n-6) from DGLA 20:3n-6, is decreased. The aim of this pilot study was to elucidate the connections between individual FAs in plasma phosphatidylcholine (PC) and the basic anthropometric, clinical, and biochemical parameters in patients with MetS-related traits.

Significant associations between the FA composition of plasma PC and anthropometric parameters (waist circumference, WHR, fat percentage, and body fat mass) were found. Waist circumference and WHR are considered markers of visceral fat accumulation, which is the central component of MetS. Male gender and age contributed to higher values  of waist circumference and WHR. In comparison with women, we found that men have characteristically higher visceral fat  mass  but lower  subcutaneous fat. Proportions of 16:0 and 18:0 in plasma and erythrocytes are associated with insulin resistance and altered glucose metabolism in nondiabetic individuals, higher risk of T2DM in both genders, worsening of glycemia in men, and coronary heart disease(CHD) risk in postmenopausal women. In individuals with MetS-related traits, an opposite (positive) association between  POA and waist circumference and a negative association with body fat percentage was found. Waist circumference is a preferential indicator of abdominal/visceral fat and is associated with cardiovascular risk factors. In patients with MetS­ related traits, we observed beneficial associations for OA, gondoic acid (20:1 n-9), and PUFAs, especially LA and DPA.   DPA (22:5n-3) was significantly and negatively associated with most body fat accumulation in­ dices. This FA is an elongated metabolite of EPA and, as an intermediary product between EPA and DHA, exerts different health effects, including anti-inflammatory actions, platelet aggregation inhibition, lipid profile improvement, and boosting of insulin secretion.   The variances of other studied parameters, for example, lipids and insulin resistance indices, were not influenced by FAs in plasma PC for this group. The results support the hypothesis that body fat deregulation is associated with altered FA profiles.

 ABSTRACT:

BACKGROUND: This study examines the associations of fatty acids (FAs) in plasma phosphatidylcholine (PC) with the anthropometrical and biochemical characteristic of patients with metabolic syndrome (MetS)-related traits. METHODS: We analyzed the FA profiles of PC in 300 persons with MetS-related traits (152 M/148F, mean age 46.9 ± 9.0 years) and in 70 healthy controls of the same age using a balanced men/women ratio and gas-liquid chromatography. Multivariate linear regression analysis was performed to determine the coefficients of determination (R²) using FA proportions of the mentioned proband characteristics. RESULTS: The FA composition of PC in patients with MetS traits was only associated with waist circumference (R² = 0.27), waist-to-hip ratio (WHR; R² = 0.41), body fat percentage (R² = 0.62), and fat mass (R² = 0.29). Positive associations were found for dihomo-γ-linolenic (DGLA), palmitic, stearic (SA), α-linolenic (ALA), and eicosapentaenoic acids, whereas negative associations were found for linoleic (LA), oleic, and docosapentaenoic acids. Palmitoleic acid (POA) was positively associated with waist circumference but negatively with fat percentage. In controls, significant associations were found for waist circumference (R² = 0.51), WHR (R² = 0.53), body fat percentage (R² = 0.60), and fat mass (R² = 0.34). DGLA and saturated FA (SFA) were positively associated, whereas docosahexaenoic, adrenic, and cis-vaccenic acids were negatively associated. The study group differed from controls as follows: lower concentrations of LA and total n-6 FA, higher indices of delta-9-desaturase and delta-6 desaturase activity and higher proportions of POA, SA, ALA, DGLA, and SFA. CONCLUSIONS: We found significant associations (R² >0.25) of FA in plasma PC with adiposity in middle-aged persons with MetS-related traits, but not with metabolic indices.