Individual serum saturated fatty acids and markers of chronic subclinical inflammation: the Insulin Resistance Atherosclerosis Study

New insights on pentadecanoic acid with special focus on its controversial essentiality: A mini-review

Pentadecanoic acid (C15:0, PDA) is an odd and minor fatty acid that has been neglected in the literature until the last decade. Indeed, as a specific fatty acid of dairy fat, PDA was only used as a biomarker of dairy fat consumption. Lately, PDA was first correlated negatively with the incidence of metabolic syndrome disorder, then its physiological effects have been investigated as a protective fatty acid. PDA supplementation has been demonstrated as negatively correlated with elevated levels of leptin, plasminogen activator inhibitor-1 and insulin, and has been shown to exhibit sensitizing insulin effects with activation of AMPK pathway. PDA also reduced the severity of metabolic dysfunction-associated steatohepatitis (MASH), notably through reduced alanine transaminase and pro-inflammatory cytokines levels. The final effect described for PDA is its ability to display anti-inflammatory properties in several pathology models. Hence, considering these multiple effects, the presence of PDA could be associated with a healthier physiological state, this raises the question of whether the presence of PDA in the body, in adequate quantities, is needed to participate to health maintenance. PDA is not synthesized in sufficient quantities endogenously, so it must be provided by the diet, mainly through dairy fat, although other types of food can also contribute to the dietary intake of PDA. Essential fatty acids are described as not being endogenously synthesized in sufficient and required quantities to maintain physiological health. Thus, PDA might gather both conditions to be described as essential, yet further investigations on both criteria are needed to enhance knowledge on this odd chain fatty acid with promising impact as potential protective supplement nutrient.

Association between the circulating very long-chain saturated fatty acid and cognitive function in older adults: findings from the NHANES

BACKGROUND

Age-related cognitive decline has a significant impact on the health and longevity of older adults. Circulating very long-chain saturated fatty acids (VLSFAs) may actively contribute to the improvement of cognitive function. The objective of this study was to investigate the associations between arachidic acid (20:0), docosanoic acid (22:0), tricosanoic acid (23:0), and lignoceric acid (24:0) with cognitive function in older adults.

METHODS

This study used a dataset derived from the 2011-2014 National Health and Nutrition Examination Survey (NHANES). A total of 806 adults (≥ 60 years) were included who underwent comprehensive cognitive testing and plasma fatty acid measurements. Multivariable linear regression, restricted cubic spline (RCS), and interaction analyses were used to assess associations between VLSFAs and cognitive function. Partial Spearman' s correlation analysis was used to examine the correlations between VLSFAs and palmitic acid (16:0), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, triglycerides, systemic inflammatory markers, and dietary nutrients.

RESULTS

Multivariable linear regression analysis, adjusting for sociodemographic, clinical conditions, and lifestyle factors, showed that 22:0 and 24:0 levels were positively associated with better global cognitive function (β = 0.37, 95% confidence interval [CI] = 0.01, 0.73; β = 0.73, 95% CI = 0.29, 1.2, respectively) as well as better CEARD-DR Z-score (β = 0.82, 95% CI = 0.36, 1.3 and β = 1.2, 95% CI = 0.63, 1.8, respectively). RCS analysis showed linear associations between higher 22:0 and 24:0 levels and better cognitive performance in both global cognitive function and CERAD-DR tests.

CONCLUSIONS

The study suggests that higher levels of 22:0 and 24:0 are associated with better global cognitive function in older adults. 22:0 and 24:0 may be important biomarkers for recognizing cognitive impairment, and supplementation with specific VLSFAs (22:0 and 24:0) may be an important intervention to improve cognitive function. Further studies are needed to elucidate the underlying biological mechanisms between VLSFAs and cognitive function.

Association of Circulating Very Long-Chain Saturated Fatty Acids With Cardiovascular Mortality in NHANES 2003-2004, 2011-2012

CONTEXT

Limited studies have shown a protective effect of very long-chain saturated fatty acids (VLSFAs) on healthy aging, diabetes, heart failure, and risk factors related to cardiovascular disease (CVD), but the role of VLSFAs on mortality risk is unclear.

OBJECTIVE

We aimed to investigate the association of serum docosanoic acid (C22:0) and serum lignoceric acid (C24:0) with all-cause and disease-specific mortality and to confirm the effect of VLSFAs on mortality risk in the whole, hyperlipidemia, and hypertensive populations.

METHODS

A total of 4132 individuals from the 2003-2004, 2011-2012 National Health and Nutrition Examination Survey (NHANES) were included in this study. There were 1326 and 1456 participants in the hyperlipidemia and hypertensive population, respectively. Mortality information was confirmed using the National Death Index (NDI). Multiple model calibration was performed using Cox regression analysis for known risk factors to explore the association between circulating VLSFAs and all-cause or CVD or coronary heart disease (CHD) mortality.

RESULTS

In the whole population, individuals with higher circulating C22:0 and C24:0 as a percentage of total serum fatty acid levels reduced the risks of mortality of all-cause (C22:0: HR = .409; 95% CI, 0.271-0.618; C24:0: HR = 0.430; 95% CI, 0.283-0.651), CVD (C22:0: HR = 0.286; 95% CI, 0.134-0.612; C24:0: HR = 0.233; 95% CI, 0.101-0.538), and CHD (C22:0: HR = 0.401; 95% CI, 0.187-0.913; C24:0: HR = 0.263; 95% CI, 0.082-0.846). Similar to the whole population, individuals with higher circulating C22:0 and C24:0 as a percentage of total serum fatty acid levels in the hyperlipidemia and hypertensive populations were also protective for all-cause, CHD, and CVD mortality.

CONCLUSION

Our results confirm the protective effect of high levels of circulating VLSFAs (C22:0 and C24:0) on CVD, CHD, and all causes of death in the whole, hyperlipidemia, and hypertensive populations.

Interaction between plasma phospholipid odd-chain fatty acids and GAD65 autoantibodies on the incidence of adult-onset diabetes: the EPIC-InterAct case-cohort study

AIMS/HYPOTHESIS

Islet autoimmunity may progress to adult-onset diabetes. We investigated whether circulating odd-chain fatty acids (OCFA) 15:0 and 17:0, which are inversely associated with type 2 diabetes, interact with autoantibodies against GAD65 (GAD65Ab) on the incidence of adult-onset diabetes.

METHODS

We used the European EPIC-InterAct case-cohort study including 11,124 incident adult-onset diabetes cases and a subcohort of 14,866 randomly selected individuals. Adjusted Prentice-weighted Cox regression estimated HRs and 95% CIs of diabetes in relation to 1 SD lower plasma phospholipid 15:0 and/or 17:0 concentrations or their main contributor, dairy intake, among GAD65Ab-negative and -positive individuals. Interactions between tertiles of OCFA and GAD65Ab status were estimated by proportion attributable to interaction (AP).

RESULTS

Low concentrations of OCFA, particularly 17:0, were associated with a higher incidence of adult-onset diabetes in both GAD65Ab-negative (HR 1.55 [95% CI 1.48, 1.64]) and GAD65Ab-positive (HR 1.69 [95% CI 1.34, 2.13]) individuals. The combination of low 17:0 and high GAD65Ab positivity vs high 17:0 and GAD65Ab negativity conferred an HR of 7.51 (95% CI 4.83, 11.69), with evidence of additive interaction (AP 0.25 [95% CI 0.05, 0.45]). Low dairy intake was not associated with diabetes incidence in either GAD65Ab-negative (HR 0.98 [95% CI 0.94, 1.02]) or GAD65Ab-positive individuals (HR 0.97 [95% CI 0.79, 1.18]).

CONCLUSIONS/INTERPRETATION

Low plasma phospholipid 17:0 concentrations may promote the progression from GAD65Ab positivity to adult-onset diabetes.

Early Pregnancy Maternal Plasma Phospholipid Saturated Fatty Acids and Fetal Growth: Findings from a Multi-Racial/Ethnic Birth Cohort in US

Saturated fatty acids (SFAs) during pregnancy are associated with disrupted metabolic programming among offspring at birth and later growth. We examined plasma phospholipid SFAs in early pregnancy and fetal growth throughout pregnancy. We enrolled 321 pregnant women from the NICHD Fetal Growth Studies-Singleton Cohort at gestational weeks 8-13. Ultrasonogram schedules were randomly assigned to capture weekly fetal growth. We measured plasma phospholipid SFAs at early pregnancy using blood samples and modeled fetal growth trajectories across tertiles of SFAs with cubic splines using linear mixed models after full adjustment. We then compared pairwise weekly fetal growth biometrics referencing the lowest tertile in each SFA using the Wald test. We found that even-chain and very long even-chain SFAs were inversely associated, whereas odd-chain SFAs were positively associated with fetal weight and size. Compared with the lowest tertile, the highest tertile of pentadecanoic acid (15:0) had a greater fetal weight and size, starting from week 13 until late pregnancy (at week 39: 3429.89 vs. 3269.08 g for estimated fetal weight; 328.14 vs. 323.00 mm for head circumference). Our findings could inspire future interventions using an alternative high-fat diet rich in odd-chain SFAs for optimal fetal growth.

Dietary fat intake is associated with insulin resistance and an adverse vascular profile in patients with T1D: a pooled analysis

BACKGROUND

Insulin resistance (IR) increases vascular risk in individuals with Type 1 Diabetes (T1D). We aimed to investigate the relationship between dietary intake and IR, as well as vascular biomarkers in T1D.

METHODS

Baseline data from three randomised controlled trials were pooled. Estimated glucose disposal rate (eGDR) was used as an IR marker. Employing multivariate nutrient density substitution models, we examined the association between macronutrient composition and IR/vascular biomarkers (tumour necrosis factor-α, fibrinogen, tissue factor activity, and plasminogen activator inhibitor-1).

RESULTS

Of the 107 patients, 50.5% were male with mean age of 29 ± 6 years. Those with lower eGDR were older with a longer diabetes duration, higher insulin requirements, and an adverse vascular profile (p < 0.05). Patients with higher degrees of IR had higher total energy intake (3192 ± 566 vs. 2772 ± 268 vs. 2626 ± 395 kcal/d for eGDR < 5.1 vs. 5.1-8.6 vs. ≥ 8.7 mg/kg/min, p < 0.001) and consumed a higher absolute and proportional amount of fat (47.6 ± 18.6 vs. 30.4 ± 8.1 vs. 25.8 ± 10.4%, p < 0.001). After adjusting for total energy intake, age, sex, and diabetes duration, increased carbohydrate intake offset by an isoenergetic decrease in fat was associated with higher eGDR (β = 0.103, 95% CI 0.044-0.163). In contrast, increased dietary fat at the expense of dietary protein intake was associated with lower eGDR (β = - 0.119, 95% CI - 0.199 to - 0.040). Replacing fat with 5% isoenergetic amount of carbohydrate resulted in decreased vascular biomarkers (p < 0.05).

CONCLUSION

Higher fat, but not carbohydrate, intake is associated with increased IR and an adverse vascular profile in patients with T1D.

Empirical Dietary Inflammatory Pattern Scores Are Not Associated with Worse Cognitive Performance in the Nurses' Health Study

BACKGROUND

Low-grade chronic inflammation associated with unhealthy diets may lead to cognitive aging.

OBJECTIVES

We evaluated whether higher long-term adherence to an empirical dietary inflammatory pattern (EDIP) was associated with lower cognitive function after age 70 y in the Nurses' Health Study.

METHODS

A total of 16,058 older (mean ± SD age: 74 ± 2 y) highly educated (≥ bachelor degree) White women completed up to 5 validated 116-item food-frequency questionnaires. An EDIP score, previously derived with the use of reduced rank regression to predict circulating inflammatory markers (i.e., C-reactive protein, TNF-α receptor 2, and IL-6), was computed based on 9 anti-inflammatory and 9 proinflammatory components. A long-term EDIP score was calculated by averaging across 5 exams. The EDIP score was categorized into quintiles, taking the first (anti-inflammatory) quintile as the reference category. Cognitive testing was performed through telephone interviews over 4 follow-up exams (1995-2008). A composite global cognition score, a composite verbal memory score, and the Telephone Interview for Cognitive Status (TICS) were calculated and averaged across the 4 exams (6 y of follow-up). Multivariable linear regressions were used to examine longitudinal relations under study.

RESULTS

Higher long-term EDIP scores (i.e., more proinflammatory) were significantly associated with worse performance on global cognitive function (P-trend= 0.018) and TICS (P-trend= 0.004) after adjustment for demographic and lifestyle factors. The associations became nonsignificant after additional adjustments for disease (related) risk factors for dementia. No association was observed between the EDIP score and verbal memory.

CONCLUSIONS

We observed no relation between long-term EDIP scores and averaged global cognitive function and verbal memory among older women. Our findings suggest no relation between long-term adherence to a proinflammatory diet and cognitive function in a large population of mostly White and generally highly educated older women. Future studies are encouraged to investigate the relation between inflammatory diets and cognitive function in other races/ethnicities and men, and over a longer follow-up period.

Changes in plasma total saturated fatty acids and palmitic acid are related to pro-inflammatory molecule IL-6 concentrations after nutritional intervention for one year

Systemic inflammation is associated with an increased risk of non-communicable diseases, such as cardiovascular diseases and diabetes. Circulating fatty acids (FA) are known to be related to these conditions, possibly through their role in inflammation, although different types of FAs can have opposite effects on inflammatory mediators. The aim of the present study was to analyze the association of plasma FAs with inflammatory biomarkers in a PREDIMED trial subsample after one year of intervention. In a one-year longitudinal study of 91 participants of the PREDIMED trial (Barcelona-Clinic center), plasma FAs and inflammatory biomarkers were analyzed using gas chromatography and ELISA, respectively. In baseline plasma, a multivariable-adjusted ordinary least squares regression model showed that n-3 polyunsaturated FAs concentrations were inversely associated with concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) and E-selectin, whereas the level of the most abundant saturated FA, palmitic acid, was directly associated with concentrations of interleukin-6 (IL-6) (β = 0.48 pg/mL, 95% CI: 0.03, 0.93 per 1-SD increase, p-value = 0.037). After one year of nutritional intervention, changes of plasma diet-derived total saturated FAs and palmitic acid were directly associated with changes in IL-6 (β = 0.59 pg/mL [95% CI: 0.28, 0.89] per 1-SD, p-value = 0.001; β = 0.64 pg/mL, 95% CI: 0.31, 0.98, p-value = 0.001), respectively, after correction for multiple testing. Our findings suggest that saturated FAs of dietary origin, especially palmitic acid, are directly involved in the increase of IL-6 in plasma.

Plasma Free Fatty Acids and Metabolic Effect in Type 2 Diabetes, an Ancillary Study from a Randomized Clinical Trial

Most nutrition studies looking at the association of food with cardiometabolic markers rely on food frequency questionnaires, which are prone to recall bias. Pentadecanoic acid, heptadecanoic acid and trans-palmitoleic acid are fatty acids that are not synthesized endogenously but are obtained from the diet, particularly dairy, making them reasonable biomarkers of dairy consumption. We investigated the association of dairy fatty acid biomarkers with glycated hemoglobin (HbA1c) and cardiovascular risk factors in type 2 diabetes (T2D). In a clinical trial, 111 participants with T2D (age 58.5 ± 8.9 years, HbA1c 8.09 ± 0.96%) were randomized into three groups: a control group that maintained baseline dairy intake, a low-fat (LF) group that incorporated ≥3 servings/day of LF dairy and a high-fat (HF) group that incorporated ≥3 servings/day of HF dairy. We compared the fatty acids (FA) composition between the three groups at 24 weeks. Pentadecanoic acid and trans-palmitoleic acid increased in the HF group by 14.1% ± 5.4% and 17.5% ± 5.1%, respectively, but not in the control and LF groups (p = 0.0474 and p = 0.0025 for group-by-time interaction, respectively). Those increases were positively associated with changes in total cholesterol, very-low-density lipoprotein cholesterol VLDL-C and triglycerides but were not associated with changes in HbA1c from baseline to 24 weeks. These results suggest that the intervention was successful and that participants were likely compliant, which supports the validity of the main trial.

Circulating fatty acid profiles are associated with protein energy wasting in maintenance hemodialysis patients: a cross-sectional study

The metabolic impact of circulating fatty acids (FAs) in patients requiring hemodialysis (HD) is unknown. We investigated the associations between plasma triglyceride (TG) FAs and markers of inflammation, insulin resistance, nutritional status and body composition. Plasma TG-FAs were measured using gas chromatography in 341 patients on HD (age = 55.2 ± 14.0 years and 54.3% males). Cross-sectional associations of TG-FAs with 13 markers were examined using multivariate linear regression adjusted for potential confounders. Higher levels of TG saturated fatty acids were associated with greater body mass index (BMI, r = 0.230), waist circumference (r = 0.203), triceps skinfold (r = 0.197), fat tissue index (r = 0.150), serum insulin (r = 0.280), and homeostatic model assessment of insulin resistance (r = 0.276), but lower malnutrition inflammation score (MIS, r =  − 0.160). Greater TG monounsaturated fatty acid levels were associated with lower lean tissue index (r =  − 0.197) and serum albumin (r =  − 0.188), but higher MIS (r = 0.176). Higher levels of TG n-3 polyunsaturated fatty acids (PUFAs) were associated with lower MIS (r =  − 0.168) and interleukin-6 concentrations (r =  − 0.115). Higher levels of TG n-6 PUFAs were associated with lower BMI (r =  − 0.149) but greater serum albumin (r = 0.112). In conclusion, TG monounsaturated fatty acids were associated with poor nutritional status, while TG n-3 PUFAs were associated with good nutritional status. On the other hand, TG saturated fatty acids and TG n-6 PUFAs had both favorable and unfavorable associations with nutritional parameters.

Circulating Very-Long-Chain Saturated Fatty Acids Were Inversely Associated with Cardiovascular Health: A Prospective Cohort Study and Meta-Analysis

Saturated fatty acids with different chain lengths have different biological activities, but little is known about very-long-chain saturated fatty acids (VLCSFAs). This study investigated the associations between the circulating VLCSFAs and cardiovascular health. This community-based cohort study included 2198 adults without carotid artery plaques (CAPs) at baseline. The percentage of baseline erythrocyte VLCSFA (arachidic acid (C20:0), behenic acid (C22:0), and lignoceric acid (C24:0)) was measured by gas chromatography. The presence of CAPs was determined at baseline and every 3 years thereafter by ultrasound examination. A meta-analysis was conducted to summarize the pooled associations between circulating VLCSFAs and the risk of cardiovascular diseases (CVDs). During a median of 7.2 years of follow-up, 573 women (35.1%) and 281 men (49.6%) were identified as CAP incident cases. VLCSFAs were inversely related with CAP risk in women (all p-trend <0.05) but not in men. Multivariate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of CAPs for the highest (vs. lowest) quartile were 0.80 (0.63–1.01) for C20:0, 0.71 (0.56–0.89) for C22:0, 0.75 (0.59–0.94) for C24:0, and 0.69 (0.55–0.87) for total VLCSFAs in women. The pooled HRs (95% CIs) of CVDs for the highest (vs. lowest) circulating VLCSFAs from seven studies including 8592 participants and 3172 CVD events were 0.67 (0.57–0.79) for C20:0, 0.66 (0.48–0.90) for C22:0, and 0.57 (0.42–0.79) for C24:0, respectively. Our findings suggested that circulating VLCSFAs were inversely associated with cardiovascular health.

Association of Major Food Sources of Fructose-Containing Sugars With Incident Metabolic Syndrome: A Systematic Review and Meta-analysis

IMPORTANCE

Sugar-sweetened beverages (SSBs) are associated with increased risk of metabolic syndrome (MetS). However, the role of other important food sources of fructose-containing sugars in the development of MetS remains unclear.

OBJECTIVE

To examine the association of major food sources of fructose-containing sugars with incident MetS.

DATA SOURCES

MEDLINE, Embase, and Cochrane Library were searched from database inception to March 24, 2020, in addition to manual searches of reference lists from included studies using the following search terms: sugar-sweetened beverages, fruit drink, yogurt, metabolic syndrome, and prospective study.

STUDY SELECTION

Inclusion criteria included prospective cohort studies of 1 year or longer that investigated the association of important food sources of fructose-containing sugars with incident MetS in participants free of MetS at the start of the study.

DATA EXTRACTION AND SYNTHESIS

Study quality was assessed using the Newcastle-Ottawa Scale. Extreme quantile risk estimates for each food source with MetS incidence were pooled using a random-effects meta-analysis. Interstudy heterogeneity was assessed (Cochran Q statistic) and quantified (I2 statistic). Dose-response analyses were performed using a 1-stage linear mixed-effects model. The certainty of the evidence was assessed using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Results were reported according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines.

MAIN OUTCOMES AND MEASURES

Pooled risk ratio (RR) of incident MetS (pairwise and dose response).

RESULTS

Thirteen prospective cohort studies (49 591 participants [median age, 51 years; range, 6-90 years]; 14 205 with MetS) that assessed 8 fructose-containing foods and MetS were included. An adverse linear dose-response association for SSBs (RR for 355 mL/d, 1.14; 95% CI, 1.05-1.23) and an L-shaped protective dose-response association for yogurt (RR for 85 g/d, 0.66; 95% CI, 0.58-0.76) and fruit (RR for 80 g/d, 0.82; 95% CI, 0.78-0.86) was found. Fruit juices (mixed and 100%) had a U-shaped dose-response association with protection at moderate doses (mixed fruit juice: RR for 125 mL/d, 0.58; 95% CI, 0.42-0.79; 100% fruit juice: RR for 125 mL/d, 0.77; 95% CI, 0.61-0.97). Honey, ice cream, and confectionary had no association with MetS incidence. The certainty of the evidence was moderate for SSBs, yogurt, fruit, mixed fruit juice, and 100% fruit juice and very low for all other food sources.

CONCLUSIONS AND RELEVANCE

The findings of this meta-analysis suggest that the adverse association of SSBs with MetS does not extend to other food sources of fructose-containing sugars, with a protective association for yogurt and fruit throughout the dose range and for 100% fruit juice and mixed fruit juices at moderate doses. Therefore, current policies and guidelines on the need to limit sources of free sugars may need to be reexamined.

Circulating Saturated Fatty Acids and Incident Type 2 Diabetes: A Systematic Review and Meta-Analysis

The effect of saturated fatty acids (SFAs) on incident type 2 diabetes (T2D) is controversial and few have systematically appraised the evidence. We conducted a comprehensive search of prospective studies examining these relationships that were published in PubMed, Web of Science, or EMBASE from 21 February 1989 to 21 February 2019. A total of 19 studies were included for systematic review and 10 for meta-analysis. We estimated the summarized relative risk (RR) and 95% confidence interval (95% CI) using a random (if I² > 50%) or a fixed effects model (if I² ≤ 50%). Although the included studies reported inconclusive results, the majority supported a protective effect of odd-chain and an adverse impact of even-chain SFAs. Meta-analysis showed that the per standard deviation (SD) increase in odd-chain SFAs was associated with a reduced risk of incident T2D (C15:0: 0.86, 0.76–0.98; C17:0: 0.76, 0.59–0.97), while a per SD increase in one even-chain SFA was associated with an increased risk of incident T2D (C14:0: 1.13, 1.09–1.18). No associations were found between other SFAs and incident T2D. In conclusion, our findings suggest an overall protective effect of odd-chain SFAs and the inconclusive impact of even- and very-long-chain SFAs on incident T2D.

Individual free fatty acids have unique associations with inflammatory biomarkers, insulin resistance and insulin secretion in healthy and gestational diabetic pregnant women

OBJECTIVE

We investigated the relationships of maternal circulating individual free fatty acids (FFA) with insulin resistance, insulin secretion and inflammatory biomarkers during mid-pregnancy.

RESEARCH DESIGN AND METHODS

The data were drawn from a prospective cohort of generally healthy pregnant women (n=1368, African-American 36%, Hispanic 48%, Caucasian 16%) in Camden, NJ. We quantitatively determined 11 FFAs, seven cytokine/adipokine, homeostatic model assessment of insulin resistance (HOMA-IR) and C-peptide levels from the fasting blood samples that were collected at 16 weeks of gestation. Multivariate analyses were performed along with separate analyses for each individual FFA.

RESULTS

High HOMA-IR (p<0.001) and C-peptide (p<0.0001) levels were positively associated with a twofold to fourfold increased risk for developing gestational diabetes mellitus (GDM). Negative relationships were found with specific FFAs (molecular percentage, palmitoleic, oleic, linolenic, myristic acids) and HOMA-IR and C-peptide levels (p<0.01 to p<0.0001). In contrast, palmitic, stearic, arachidonic, dihomo-γ-linolenic (DGLA) and docosahexaenoic acids were positively associated with HOMA-IR and C-peptide (p<0.01 to p<0.0001). The individual FFAs also predicted cytokine/adipokine levels. For example, women who had elevated DGLA (highest quartile) were twice as (adjusted OR 2.06, 95% CI 1.42 to 2.98) likely to have higher interleukin (IL)-8 (p<0.0001) levels. Conversely, women with high palmitoleic, oleic, and linolenic acid levels had reduced odds (≥2-fold, p<0.01 to p<0.001) for having higher IL-8, IL-6 or tumor necrosis factor-alpha levels.

CONCLUSION

Our results suggest that maternal individual FFAs uniquely affect insulin resistance and secretion. The effects are either direct or indirect via modulation of the inflammatory response. Modifying the composition of FFAs may help in reducing the risk of GDM.

Chronic low-dose exposure of nonylphenol alters energy homeostasis in the reproductive system of female rats

Nonylphenol (NP) as a confirmed endocrine disrupt chemical that causes reproductive and developmental toxicity. Previous studies focused only on short-term, high-dose exposure in vivo, or in vitro on female reproductive toxicity, which cannot accurately simulate the real human exposure scenario. The present study aims to explore NP toxicity and the underlying mechanisms of chronic low-dose NP exposure (500 μg/kg·bw/day, for 8 weeks) in the reproductive system of female rats. The results indicated that NP exposure caused female reproductive toxicity, including alterations in serum 17β-estradiol (E₂) levels, endometria hyperplasia, altered oogenesis and significant changes in the metabolic profile observed in urine, serum, uterus and ovary. Furthermore, expression of the energy-sensitive proteins carnitine palmitoyltransferase I (CPTI), adenosine 5'-monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor gamma (PPAR-γ) were found to be down-regulated in uterus under NP exposure, which suggested the impaired fatty acid oxidation. Accordingly, a comprehensive metabolomics study in key reproductive tissues and body fluids revealed that 12 metabolites were associated with energy metabolism as potential biomarkers for the evaluation of low toxicity at early stages, with L-carnitines being the most representative ones. The present findings provide evidence that chronic low-dose NP exposure can significantly disrupt energy homeostasis in females, thus offering further insights into NP reproductive toxicity.