Relationship between Body Mass Index, C-Peptide, and Delta-5-Desaturase Enzyme Activity Estimates in Adult Males

Altered Red Blood Cell Fatty Acid and Serum Adipokine Profiles in Subjects with Obesity

BACKGROUND

Adipokines, as well as the fatty acid profile of red blood cell (RBC) membranes, are known to play important roles in the development and progression of metabolic complications induced by obesity. Thus, the objective of this study is to compare the serum adipokine profile and the RBC membrane fatty acid profile of normal-weight and obese adults, and to analyze their relationship with serum biochemical parameters.

METHODS

An observational case-control study was performed in 75 normal-weight and obese adult subjects. Biochemical serum parameters, eight serum adipokines and the RBC membrane fatty acid profiles were measured. Associations between parameters were established using regression analysis.

RESULTS

Subjects with obesity showed increased levels of leptin, fibroblast growth factor 21 (FGF21) and overexpressed nephroblastoma (NOV/CCN3), decreased adiponectin, and similar levels of vaspin and chemerin compared to normal-weight subjects. Significant positive and negative correlations were found with triglycerides and high-density lipoprotein-cholesterol (HDL-c), respectively. An increase in the total ω-6 fatty acids in the RBC membrane fatty acid profiles in subjects with obesity was observed, because of higher levels of both dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA), and decreased total ω-3 fatty acids, mainly due to lower levels of docosahexaenoic acid (DHA). The ω-6/ω-3 ratio in the RBCs was significantly higher, suggesting an inflammatory status, as was also suggested by a reduced adiponectin level. A negative association between DGLA and adiponectin, and a positive association between DHA and serum triglycerides, was observed.

CONCLUSIONS

Important alterations in serum adipokine and RBC fatty acid profiles are found in subjects with obesity.

Cholesterol and glucose profiles according to different fasting C-peptide levels: a cross-sectional analysis in a healthy cohort from the Czech Republic

The relationship between glycaemia and lipoprotein metabolism has not been completely clarified, and slight differences may be found between local authors, trials and evaluated parameters. Therefore this cross-sectional study investigated fasting cholesterol and glucose levels along with the determination of atherogenic index in a cohort of healthy individuals from the Czech Republic in relation to their fasting C-peptide levels. Data were collected between 2009 and 2018 and a total of 3189 individuals were stratified by C-peptide reference range (260-1730 pmol/l) into three groups - below (n = 111), within (n = 2952) and above (n = 126). Total, HDL, LDL cholesterol and atherogenic index were used to compare lipoprotein levels by relevant C-peptide concentrations. Participants using the supplements to affect lipid or glycaemia metabolism were excluded from this study. The evaluation of blood parameters in a fasting state included correlations between C-peptide and cholesterols, differences of variances (F-test) and the comparison of lipoprotein mean values (t-test) between the groups created by the C-peptide reference range. Mean values of total (4.9, 5.1, 5.3 mmol/l), LDL (2.6, 3.1, 3.4 mmol/l) cholesterol and atherogenic index (2.1, 2.8, 3.7) were higher with increasing C-peptide levels, whereas HDL was inversely associated with fasting C-peptide concentration. A positive and negative correlation between atherogenic index (rxy = 0.36) and HDL level (rxy = -0.36) with C-peptide values was found. Differences of HDL, LDL and atherogenic index were, in particular, recorded between the groups below and above the reference range of C-peptide (p ≤ 0.001). Considerable differences (p ≤ 0.001) were also observed for the same lipoprotein characteristics between the groups above and within the C-peptide reference. Generally, the type of cholesterol is crucial for the evaluation of specific changes concerning the C-peptide range. Lipoprotein concentrations differ in relation to C-peptide - not only below and above the physiological range, but also inside and outside of it. Conclusions: Fasting levels of cholesterol, plasma glucose, and atherogenic index were strongly associated with fasting C-peptide levels in healthy individuals. Our data suggest that fasting C-peptide could serve as a biomarker for the early detection of metabolic syndrome and/or insulin resistance prior to the manifestation of type 2 diabetes.

Plasma Lipolysis and Changes in Plasma and Cerebrospinal Fluid Signaling Lipids Reveal Abnormal Lipid Metabolism in Chronic Migraine

Background

Lipids are a primary storage form of energy and the source of inflammatory and pain signaling molecules, yet knowledge of their importance in chronic migraine (CM) pathology is incomplete. We aim to determine if plasma and cerebrospinal fluid (CSF) lipid metabolism are associated with CM pathology.

Methods

We obtained plasma and CSF from healthy controls (CT, n = 10) or CM subjects (n = 15) diagnosed using the International Headache Society criteria. We measured unesterified fatty acid (UFA) and esterified fatty acids (EFAs) using gas chromatography-mass spectrometry. Glycerophospholipids (GP) and sphingolipid (SP) levels were determined using LC-MS/MS, and phospholipase A₂ (PLA₂) activity was determined using fluorescent substrates.

Results

Unesterified fatty acid levels were significantly higher in CM plasma but not in CSF. Unesterified levels of five saturated fatty acids (SAFAs), eight monounsaturated fatty acids (MUFAs), five ω-3 polyunsaturated fatty acids (PUFAs), and five ω-6 PUFAs are higher in CM plasma. Esterified levels of three SAFAs, eight MUFAs, five ω-3 PUFAs, and three ω-6 PUFAs, are higher in CM plasma. The ratios C20:4n-6/homo-γ-C20:3n-6 representative of delta-5-desaturases (D5D) and the elongase ratio are lower in esterified and unesterified CM plasma, respectively. In the CSF, the esterified D5D index is lower in CM. While PLA₂ activity was similar, the plasma UFA to EFA ratio is higher in CM. Of all plasma GP/SPs detected, only ceramide levels are lower (p = 0.0003) in CM (0.26 ± 0.07%) compared to CT (0.48 ± 0.06%). The GP/SP proportion of platelet-activating factor (PAF) is significantly lower in CM CSF.

Conclusions

Plasma and CSF lipid changes are consistent with abnormal lipid metabolism in CM. Since plasma UFAs correspond to diet or adipose tissue levels, higher plasma fatty acids and UFA/EFA ratios suggest enhanced adipose lipolysis in CM. Differences in plasma and CSF desaturases and elongases suggest altered lipid metabolism in CM. A lower plasma ceramide level suggests reduced de novo synthesis or reduced sphingomyelin hydrolysis. Changes in CSF PAF suggest differences in brain lipid signaling pathways in CM. Together, this pilot study shows lipid metabolic abnormality in CM corresponding to altered energy homeostasis. We propose that controlling plasma lipolysis, desaturases, elongases, and lipid signaling pathways may relieve CM symptoms.

The FADS1 Genotype Modifies Metabolic Responses to the Linoleic Acid and Alpha-linolenic Acid Containing Plant Oils-Genotype Based Randomized Trial FADSDIET2

SCOPE

The article investigates the FADS1 rs174550 genotype interaction with dietary intakes of high linoleic acid (LA) and high alpha-linolenic acid (ALA) on the response of fatty acid composition of plasma phospholipids (PLs), and of markers of low-grade inflammation and glucose-insulin homeostasis.

METHODS AND RESULTS

One-hundred thirty homozygotes men for FADS1 rs174550 SNP (TT and CC genotypes) were randomized to an 8-week intervention with either LA- or ALA-enriched diet (13 E% PUFA). The source of LA and ALA are 30-50 mL of sunflower oil (SFO, 62-63% LA) and Camelina sativa oil (CSO, 30- are randomized to an 35% ALA), respectively. In the SFO arm, there is a significant genotype x diet interaction for the proportion of arachidonic acid in plasma phospholipids (p < 0.001), disposition index (DI₃₀ ) (p = 0.039), and for serum high-sensitive c-reactive protein (hs-CRP, p = 0.029) after excluding the participants with hs-CRP concentration of >10 mg L^-1 and users of statins or anti-inflammatory therapy. In the CSO arm, there are significant genotype x diet interactions for n-3 polyunsaturated fatty acids, but not for the clinical characteristics.

CONCLUSIONS

The FADS1 genotype modifies the response to high PUFA diets, especially to high-LA diet. These findings suggest that approaches considering FADS variation may be useful in personalized dietary counseling.

Exercise Training Alters Red Blood Cell Fatty Acid Desaturase Indices and Adipose Tissue Fatty Acid Profile in African Women with Obesity

OBJECTIVE

This study assessed the changes in red blood cell total phospholipid (RBC-TPL) and subcutaneous adipose tissue (SAT) fatty acid (FA) composition in response to 12 weeks of exercise training in South African women with obesity and the associations with changes in cardiometabolic risk factors.

METHODS

Previously sedentary women were randomized into control (n = 15) or exercise (n = 20) groups. RBC-TPL and SAT FA profiles, SAT gene expression, systemic inflammatory markers, liver fat, and insulin sensitivity (S_I ) were measured before and after the intervention.

RESULTS

Compared with control, exercise training induced decreases in RBC-TPL dihomo-γ-linolenic acid content and stearoyl-CoA desaturase-1 and increased delta-5 desaturase-estimated activity (P < 0.05). In the combined group, these changes correlated with changes in circulating leptin and TNFα (P < 0.05), as well as lower liver fat (P < 0.01). Exercise training decreased saturated FA (lauric and myristic acids) and increased polyunsaturated FA (eicosadienoic and adrenic acids) (P < 0.05) in abdominal SAT, whereas γ-linolenic acid decreased (P < 0.01) in gluteal SAT. These changes in RBC-TPL and SAT FA compositions were not associated with changes in SAT gene expression and S_I .

CONCLUSIONS

Exercise training alters RBC-TPL desaturase activities, which correlate with lower liver fat and systemic inflammation but not with the improvement of S_I .

Long-chain ω-6 plasma phospholipid polyunsaturated fatty acids and association with colon adenomas in adult men: a cross-sectional study

Dietary lipid intake can be associated with an increased risk for colorectal cancer depending on its composition. Carcinogenesis alters lipid metabolism to facilitate cell growth and survival. For instance, metabolites of polyunsaturated fatty acids (PUFAs) are associated with increasing colon cell proliferation. Moreover, precancerous colon lesions (i.e. adenomas) increase the risk for colorectal cancer. In this study, we investigated associations between plasma PUFAs and the number of colon polyps and polyp type (i.e. hyperplastic and adenoma). Healthy male participants (n=126) of 48-65 years of age were recruited before a routine colonoscopy screening. Plasma phospholipid (PPL) PUFAs were isolated by means of solid phase extraction and methylated. Fatty acid methyl esters were analyzed using gas chromatography. Factor analysis was used to cluster PUFAs into groups, and then generated factors and individual PUFAs were analyzed using polytomous logistic regression. In our age-adjusted and smoking-adjusted polytomous logistic regression, for each unit increase in PPL docosatetraenoic acid (DTA), individuals were 1.43 (1.00-2.06) and 1.33 (0.99-1.80) times more likely to have hyperplastic polyps and adenomas rather than no polyps, respectively. In our factor analysis, high PPL ω-6 PUFA and trans-fatty acid loading scores were associated with increased odds of adenoma presence rather than no polyps. Increases in long-chain PPL ω-6 PUFAs are associated with an increased risk for adenomas. As relative levels of DTA increase in PPLs, individuals had increased odds of having hyperplastic polyps and adenomas. Elevated conversion of ω-6 PUFAs to longer-chain ω-6s such as DTA may indicate altered PUFA metabolism at the tissue level.

Obesity, adipokines, and C-peptide are associated with distinct plasma phospholipid profiles in adult males, an untargeted lipidomic approach

Obesity is associated with dysregulated lipid metabolism and adipokine secretion. Our group has previously reported obesity and adipokines are associated with % total fatty acid (FA) differences in plasma phospholipids. The objective of our current study was to identify in which complex lipid species (i.e., phosphatidylcholine, sphingolipids, etc) these FA differences occur. Plasma lipidomic profiling (n = 126, >95% Caucasian, 48–65 years) was performed using chromatographic separation and high resolution tandem mass spectrometry. The responses used in the statistical analyses were body mass index (BMI), waist circumference (WC), serum adipokines, cytokines, and a glycemic marker. High-dimensional statistical analyses were performed, all models were adjusted for age and smoking, and p-values were adjusted for false discovery. In Bayesian models, the lipidomic profiles (over 1,700 lipids) accounted for >60% of the inter-individual variation of BMI, WC, and leptin in our population. Across statistical analyses, we report 51 individual plasma lipids were significantly associated with obesity. Obesity was inversely associated lysophospholipids and ether linked phosphatidylcholines. In addition, we identify several unreported lipids associated with obesity that are not present in lipid databases. Taken together, these results provide new insights into the underlying biology associated with obesity and reveal new potential pathways for therapeutic targeting.

Increasing dietary EPA and DHA influence estimated fatty acid desaturase activity in systemic organs which is reflected in the red blood cell in mice

Delta-5 (D5D) and delta-6 (D6D) desaturase are key enzymes in fatty acid (FA) metabolism. Dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may alter tissue FA composition via D5D and D6D. The purpose was to determine the relationship between dietary EPA + DHA, estimated desaturase activities of various tissues and the reflection of desaturase activity in the red blood cell (RBC). Mice were fed diets with increasing percent of energy from EPA + DHA. Phospholipid FA composition of heart, muscle, spleen, lung, adipose tissues and RBC were analysed. D5D and D6D enzyme activity estimates (EAE) were calculated as the ratio of 20:4/20:3 and 20:3/18:2, respectively. D5D EAE decreased in all tissues, except muscle, with increasing dietary EPA + DHA. RBC D5D EAE positively correlated with D5D EAE in all tissues. RBC D6D EAE positively correlated with muscle and inversely correlated with adipose D6D EAE. Our findings suggest differential influence of dietary EPA + DHA upon tissue desaturase activities.

Obesity is positively associated with arachidonic acid-derived 5- and 11-hydroxyeicosatetraenoic acid (HETE)

BACKGROUND

Oxylipids are oxygenated polyunsaturated fatty acid (PUFA) metabolites that are responsible for the onset and resolution of the inflammatory response. Enzymatic oxygenation through the lipoxygenase (LOX) or cytochrome P450 (CYP) pathways can form oxylipids that have either proinflammatory or proresolving functions depending on the type of PUFA substrate and degree of metabolism. The objective of this study was to determine how PUFA substrates and their corresponding oxylipids are associated with obesity.

METHODS

Plasma non-esterified FA and oxylipids were isolated from 123 Caucasian males using solid phase extraction and quantified using high performance liquid chromatography-tandem mass spectrometry. Statistical analyses included linear regressions and polytomous logistic regressions, and the responses were body mass index (BMI) and waist circumference (WC), and serum leptin, total adiponectin, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-peptide. Models were adjusted for age and smoking, and p-values were corrected for false discovery per Benjamini-Hochberg and Bonferroni.

RESULTS

We report that BMI, WC, and several serum cytokines were highly associated arachidonic acid (ARA)-derived hydroxyeicosatetraenoic acids (HETEs), and vicinal diols (i.e., alcohols on adjacent carbon atoms) derived from several PUFAs. There was a significant linear relationship between BMI, WC, and serum leptin, and ARA-derived 5-, 11-, and 15-HETE. Specifically, BMI and WC were positively associated with proinflammatory 5- and 11-hydroxyeicosatetraenoic acid (HETE), even after normalization to ARA concentrations and false discovery p-value correction. Individuals with 5-HETE concentrations >5.01nmol/L or 11-HETE concentrations and >0.89nmol/L were over 5 times more likely to be obese compared to those with ≤1.86nmol/L and ≤0.39nmol/L, respectively. Vicinal diols from linoleic, eicosapentaenoic, and docosahexaenoic acid were inversely associated with obesity. Across all statistical tests, vicinal diols were inversely associated with obesity whether normalized to parent PUFA concentrations or normalized to precursor epoxides. Interestingly, the proinflammatory cytokines IL-6 and TNF-α were not associated with any oxylipids. Since 5-HETE is a 5LOX product, 11-HETE is marker of lipid peroxidation, and vicinal diols are formed through soluble epoxide hydrolase (sEH) metabolism of CYP epoxygenated PUFAs, therefore, these results indicate that obesity is likely associated with altered metabolism with distinct oxygenating pathways. Taken together, our results indicate that obesity is associated with specific oxylipids indicative of altered PUFA metabolism through several pathways (i.e., LOX, reactive oxygen species, and sEH and CYP epoxygenase), rather than attributed solely to altered dietary PUFA intake.

Alterations of specific lipid groups in serum of obese humans: a review

Obesity is a major contributor to the dysfunction of liver, cardiac, pulmonary, endocrine and reproductive system, as well as a component of metabolic syndrome. Although development of obesity-related disorders is associated with lipid abnormalities, most previous studies dealing with the problem in question were limited to routinely determined parameters, such as serum concentrations of triacylglycerols, total cholesterol, low-density and high-density lipoprotein cholesterol. Many authors postulated to extend the scope of analysed lipid compounds and to study obesity-related alterations in other, previously non-examined groups of lipids. Comprehensive quantitative, structural and functional analysis of specific lipid groups may result in identification of new obesity-related alterations. The review summarizes available evidence of obesity-related alterations in various groups of lipids and their impact on health status of obese subjects. Further, the role of diet and endogenous lipid synthesis in the development of serum lipid alterations is discussed, along with potential application of various lipid compounds as risk markers for obesity-related comorbidities.