BACKGROUND: Long-chain free fatty acids (FFAs) are associated with risk of incident diabetes. However, a comprehensive assessment of the associations in normoglycemic populations is lacking.
OBJECTIVE: Our study aimed to comprehensively investigate the prospective associations and patterns of FFA profiles with diabetes risk among normoglycemic Chinese adults.
METHODS: This is a prospective nested case-control study from the China Cardiometabolic Disease and Cancer Cohort (4C) study. We quantitatively measured 53 serum FFAs using a targeted metabolomics approach in 1707 incident diabetes subjects and 1707 propensity score-matched normoglycemic controls. Conditional logistic regression models were employed to estimate odds ratios (ORs) for associations. Least Absolute Shrinkage and Selection Operator (LASSO) penalty regression and quantile g-computation (qg-comp) analyses were implemented to estimate the association between multi-FFA exposures and incident diabetes.
RESULTS: The majority of odd-chain FFAs exhibited an inverse association with incident diabetes, wherein the ORs per SD increment of all 7 saturated fatty acids (SFAs), monounsaturated fatty acid (MUFA) 15:1, and polyunsaturated fatty acid (PUFA) 25:2 were ranging from 0.79 to 0.88 (95% CIs ranging between 0.71 and 0.97). Even-chain FFAs comprised 99.3% of total FFAs and displayed heterogeneity with incident diabetes. SFAs with 18-26 carbon atoms are inversely linked to incident diabetes, with ORs ranging from 0.81 to 0.86 (95% CIs ranging between 0.73 and 0.94). MUFAs 26:1 (OR: 0.85; 95% CI: 0.76, 0.94), PUFAs 20:4 (OR: 0.84; 95% CI: 0.75, 0.94), and 24:2 (OR: 0.87; 95% CI: 0.78, 0.97) demonstrated significant associations. In multi-FFA exposure model, 24 FFAs were significantly associated with incident diabetes, most of which were consistent with univariate results. The mixture OR was 0.78 (95% CI: 0.61, 0.99; P = 0.04159). Differential correlation network analysis revealed pre-existing perturbations in intraclass and interclass FFA coregulation before diabetes onset.
CONCLUSIONS: These findings underscore the variations in diabetes risk associated with FFAs across chain length and unsaturation degree, highlighting the importance of recognizing FFA subtypes in the pathogenesis of diabetes.

BACKGROUND: Fatty acid-binding protein 4 (FABP4) has been associated with cardiovascular disease and diabetes. Acute aerobic exercise increases circulating FABP4 concentrations, but the underlying mechanisms remain unclear. The purpose of this study was to investigate the effects of inhibition of lipolysis by carbohydrate ingestion on circulating FABP4 concentrations during and after acute aerobic exercise in healthy men.
METHODS: Men aged between 20 and 40, with no exercise habits and no metabolic diseases, were recruited. In a randomized crossover design, the participants underwent a carbohydrate-ingestion exercise (CE) and a fasted exercise (FE) trial. The CE trial consisted of 40-min acute aerobic exercise with ingestion of carbohydrates and 60-min bed rest. The FE trial followed the same protocol as the CE trial but without carbohydrate ingestion. Venous blood samples were collected to measure hormones (adrenaline, noradrenaline, and insulin) metabolites (glycerol, free fatty acids, and glucose), and FABP4 concentrations. Ventilation and gas exchange were also collected to measure substrate oxidation.
RESULTS: Thirteen healthy men participated in and completed both the CE and FE trials. The insulin concentration was more than 4 times higher in the CE trial than in the FE trial (p < 0.004, effect size [ES] > 2.00). Free fatty acid concentrations were more than 4 times lower in the CE trial than in the FE trial (p < 0.02, ES > 2.04). However, there was no significant difference in the changes in circulating FABP4 concentrations between the CE and FE trials (p = 0.108), which did not change during aerobic exercise and significantly increased post-aerobic exercise in both trials (p < 0.002, ES > 1.212). Changes in FABP4 concentrations following aerobic exercise were not significantly correlated with changes in glycerol or free fatty acid concentrations during aerobic exercise.
CONCLUSIONS: The results suggest that suppression of lipolysis and elevation of insulin are not strongly involved in increases in FABP4 secretion following acute aerobic exercise.

BACKGROUND: Vascular insulin resistance is commonly observed in obesity and diabetes; yet, insulin action across the vascular tree and the relationship between insulin responses at different vascular locations remains incompletely defined.
OBJECTIVE: To elucidate the impact of elevated free fatty acids (FFAs) on insulin action across the arterial tree and define the relationship among insulin actions in the different arterial segments.
METHODS: This randomized crossover study assigned healthy lean adults to 2 separate admissions with euglycemic insulin clamp superimposed for the final 120 minutes of 5-hour lipid or matched-volume saline infusion. Vascular measures including peripheral and central arterial blood pressure, brachial artery flow-mediated dilation (FMD), carotid femoral pulse wave velocity (cfPWV), augmentation index (AIx), pulse wave separation analysis, subendocardial viability ratio (SEVR), and skeletal and cardiac muscle microvascular perfusion were determined before and after insulin clamp. Insulin-mediated whole body glucose disposal was calculated.
RESULTS: Insulin enhanced FMD, AIx, reflection magnitude, and cardiac and skeletal muscle microvascular perfusion. Elevation of plasma FFA concentrations to the levels seen in the postabsorptive state in people with insulin resistance suppressed SEVR, blunted insulin-induced increases in FMD and cardiac and skeletal muscle microvascular blood volume, and lowered insulin\'s ability to reduce AIx and reflection magnitude. In multivariate regression, insulin-mediated muscle microvascular perfusion was independently associated with insulin-mediated FMD and cfPWV.
CONCLUSIONS: Clinically relevant elevation of plasma FFA concentrations induces pan-arterial insulin resistance, the vascular insulin resistance outcomes are interconnected, and insulin-mediated muscle microvascular perfusion associates with cardiovascular disease predictors. Our data provide biologic plausibility whereby a causative relationship between FFAs and cardiovascular disease could exist, and suggest that further attention to interventions that block FFA-mediated vascular insulin resistance may be warranted.

BACKGROUND: The association between free fatty acids (FFAs) and unfavorable clinical outcomes has been reported in the general population. However, evidence in the secondary prevention population is relatively scarce.
OBJECTIVE: We aimed to examine the relationship between FFA and cardiovascular risk in patients with coronary artery disease (CAD).
METHODS: This study was based on a multicenter cohort of patients with CAD enrolled from January 2015 to May 2019. The primary outcome was all-cause death. Secondary outcomes included cardiac death and major adverse cardiovascular events (MACE), a composite of death, myocardial infarction, and unplanned revascularization.
RESULTS: During a follow-up of 2 years, there were 468 (3.0%) all-cause deaths, 335 (2.1%) cardiac deaths, and 1279 (8.1%) MACE. Elevated FFA levels were independently associated with increased risks of all-cause death, cardiac death, and MACE (all P < .05). Moreover, When FFA were combined with an original model derived from the Cox regression, there were significant improvements in discrimination and reclassification for prediction of all-cause death (net reclassification improvement [NRI] 0.245, P < .001; integrated discrimination improvement [IDI] 0.004, P = .004), cardiac death (NRI 0.269, P < .001; IDI 0.003, P = .006), and MACE (NRI 0.268, P < .001; IDI 0.004, P < .001). Notably, when stratified by age, we found that the association between FFA with MACE risk appeared to be stronger in patients aged ≥60 years compared with those aged <60 years.
CONCLUSIONS: In patients with CAD, FFAs are associated with all-cause death, cardiac death, and MACE. Combined evaluation of FFAs with other traditional risk factors could help identify high-risk individuals who may require closer monitoring and aggressive treatment.

Increased free fatty acid (FFA) levels are known to be strongly associated with mortality in coronary artery disease (CAD) patients and the development of type 2 diabetes (T2DM). However, few studies have been large enough to accurately examine the relationship between FFA levels and mortality in CAD patients with T2DM.
From December 2016 to October 2021, 10 395 CAD patients enrolled in PRACTICE, a prospective cohort study in China, were divided into four groups according to baseline FFA concentration. We investigated mortality, including all-cause mortality (ACM) and cardiac mortality (CM), as the primary endpoint. The secondary endpoints were major adverse cardiovascular and cerebrovascular events (MACCEs) and major adverse cardiovascular events (MACEs). The median follow-up time was 24 months. In the total cohort, there were 222 ACMs, 164 CMs, 718 MACEs, and 803 MACCEs recorded. After controlling for baseline variables, the association between FFA levels and the risk of mortality presented a non-linear U-shaped curve, with the lowest risk at 310 µmol/L. We also identified a non-linear U-shaped relationship for ischaemic events (MACE or MACCE) with the lowest risk at 500 µmol/L. Subgroup analysis showed that a U-shaped relationship between FFA and mortality or ischaemic events was observed only in individuals with T2DM but not in non-diabetic CAD patients.
A non-linear U-shaped association was identified between baseline FFA levels and mortality or ischaemic events in CAD patients with T2DM.
From December 2016 to October 2021, 10 395 coronary artery disease (CAD) patients enrolled in PRACTICE, a prospective cohort study in China, were divided into four groups according to baseline free fatty acid (FFA) concentration. We investigated mortality, including all-cause mortality (ACM), and cardiac mortality (CM), as the primary endpoints. The secondary endpoints were major adverse cardiovascular and cerebrovascular events (MACCEs) and major adverse cardiovascular events (MACEs). The median follow-up time was 24 months. Finally, we were surprised to find that high and low FFA levels were associated with a higher risk of mortality and ischaemic events in CAD patients with T2DM. Baseline plasma FFA levels may be a more powerful, effective, and easily detectable biomarker of adverse outcomes in CAD patients with T2DM. As the FFA increases, a U-shaped curve appears in the poor long-term prognosis.

Vitamin D deficiency is a common finding in overweight/obese pregnant women and is associated with increased risk for adverse pregnancy outcome. Both maternal vitamin D deficiency and maternal obesity contribute to metabolic derangements in pregnancy. We aimed to assess the effects of vitamin D3 supplementation in pregnancy versus placebo on maternal and fetal lipids. Main inclusion criteria were: women <20 weeks’ gestation, BMI ≥ 29 kg/m2. Eligible women (n = 154) were randomized to receive vitamin D3 (1600 IU/day) or placebo. Assessments were performed <20, 24−28 and 35−37 weeks and at birth. Linear regression models were used to assess effects of vitamin D on maternal and cord blood lipids. In the vitamin D group significantly higher total 25-OHD and 25-OHD3 levels were found in maternal and cord blood compared with placebo. Adjusted regression models did not reveal any differences in triglycerides, LDL-C, HDL-C, free fatty acids, ketone bodies or leptin between groups. Neonatal sum of skinfolds was comparable between the two groups, but correlated positively with cord blood 25-OH-D3 (r = 0.34, p = 0.012). Vitamin D supplementation in pregnancy increases maternal and cord blood vitamin D significantly resulting in high rates of vitamin D sufficiency. Maternal and cord blood lipid parameters were unaffected by Vitamin D3 supplementation.

UNASSIGNED: Both insulin and plasma exchange (PE) are used in hypertriglyceridemic acute pancreatitis (HTG-AP). Our aim was to compare the efficacy of both treatments.
UNASSIGNED: A randomized, parallel group study performed in a tertiary hospital in 22 HTG-AP patients with non-severe prognosis and triglycerides between 15 and 40 mmol/L. Patients were randomized to daily PE or insulin infusion until triglycerides were <10 mmol/L. Primary outcome was % reduction in triglycerides within 24 h. Secondary outcomes were days needed to lower triglycerides <10 mmol/L, highest CRP and percentage of patients with a severe course of pancreatitis.
UNASSIGNED: There was a trend toward a greater decrease in triglycerides within the first 24 h in the PE group (67 ± 17% vs. 53 ± 17%, p = 0.07), but the absolute difference was modest [mean difference of 6 mmol/L (14% of initial value)]. Triglycerides fell below 10 mmol/L in a median (IQR) of 1 (1-2) and 2 (1-2) days, respectively (p = 0.25). Secondary outcomes related to disease severity were also comparable: highest CRP 229 vs. 211 mg/L (p = 0.69) and severe course of pancreatitis in 2/11 cases in both groups (p = 1.0). Regarding treatment complications, there was one mild hypoglycemia and one allergic reaction during PE. Survival was 100% in both groups.
UNASSIGNED: There was no significant difference, but only a trend toward a greater decrease in triglycerides with PE, and the clinical course was also comparable. These results do not support universal use of PE in patients with HTG-AP.
UNASSIGNED: [ClinicalTrials.gov], identifier [NCT02622854].

BACKGROUND: Aspergillus sp. has been used in traditional Japanese fermented foods. Protease-containing culture products of A. oryzae have been applied as the adjunct enzyme source to enrich the flavor in ripened cheese. Although proteolysis was stimulated, the increase of free fatty acids (FFA) was recognized in some products. Since an excess amount of FFA accumulation can cause rancidity in cheese products, the assessment of lipase activity was considered to be essential for the cheese adjunct preparation.
RESULTS: Although an equal lipase activity from the adjunct materials of A. kawachii NBRC 4308, A. luchuensis RIB 2604 and A. oryzae AHU 7139 was applied to semi-hard cheese, the FFA level was significantly higher in A. oryzae cheese than in the others. Furthermore, the profiles of volatile components were different in experimental cheeses. An in vitro study with experimental curds demonstrated that the high FFA might not depend on the lipase retainability on curds. On the contrary, the pronounced activation of the lipases occurred in A. oryzae after incubation with the curds. Moreover, incubation of the insoluble lipase that had been attached to the cells with skim milk curd extracts allowed the release of lipases from the cells into the medium with remarkable activation.
CONCLUSIONS: A. oryzae AHU 7139 possessed a complex lipolytic system comprising extracellular and cell-binding lipases that were attributed to the increase in FFA in A. oryzae cheese. © 2022 Society of Chemical Industry.

The presence of circulating microbiome in blood has been reported in both physiological and pathological conditions, although its origins, identities and function remain to be elucidated. This study aimed to investigate the presence of blood microbiome by quantitative real-time PCRs targeting the 16S rRNA gene. To our knowledge, this is the first study in which the circulating microbiome has been analyzed in such a large sample of individuals since the study was carried out on 1285 Randomly recruited Age-Stratified Individuals from the General population (RASIG). The samples came from several different European countries recruited within the EU Project MARK-AGE in which a series of clinical biochemical parameters were determined. The results obtained reveal an association between microbial DNA copy number and geographic origin. By contrast, no gender and age-related difference emerged, thus demonstrating the role of the environment in influencing the above levels independent of age and gender at least until the age of 75. In addition, a significant positive association was found with Free Fatty Acids (FFA) levels, leukocyte count, insulin, and glucose levels. Since these factors play an essential role in both health and disease conditions, their association with the extent of the blood microbiome leads us to consider the blood microbiome as a potential biomarker of human health.

Serum free fatty acid (FFA) concentrations are associated with coronary heart disease and diabetes mellitus (DM). Few studies focused on the relationship between serum FFA levels and coronary artery calcification (CAC).
This was a retrospective, single-centered study recruiting patients underwent FFA quantification, coronary angiography and intravascular ultrasound (IVUS). CAC severity was assessed with the maximum calcific angle (arc) of the calcified plaque scanned by IVUS. Patients with an arc ≥ 180° were classified into the severe CAC (SCAC) group, and those with an arc < 180° were classified into the non-SCAC group. Clinical characteristics, serum indices were compared between 2 groups. Logistic regression, receiver operating characteristic (ROC) curves and area under the curves (AUC) were performed.
Totally, 426 patients with coronary artery disease were consecutively included. Serum FFA levels were significantly higher in the SCAC group than non-SCAC group (6.62 ± 2.17 vs. 5.13 ± 1.73 mmol/dl, p < 0.001). Logistic regression revealed that serum FFAs were independently associated with SCAC after adjusting for confounding factors in the whole cohort (OR 1.414, CI 1.237-1.617, p < 0.001), the non-DM group (OR 1.273, CI 1.087-1.492, p = 0.003) and the DM group (OR 1.939, CI 1.388-2.710, p < 0.001). ROC analysis revealed a serum FFA AUC of 0.695 (CI 0.641-0.750, p < 0.001) in the whole population. The diagnostic predictability was augmented (AUC = 0.775, CI 0.690-0.859, p < 0.001) in the DM group and decreased (AUC = 0.649, CI 0.580-0.718, p < 0.001) in the non-DM group.
Serum FFA levels were independently associated with SCAC, and could have some predictive capacity for SCAC. The association was strongest in the DM group.