Essential Fatty Acids and Osteoarthritis

OBJECTIVE

Inflammation worsens joint destruction in osteoarthritis (OA) and aggravates pain. Although n-3 fatty acids reduce inflammation, different n-3 fatty acids have different effects on inflammation and clinical outcomes, with eicosapentaenoic acid (EPA) having the strongest effect. We examined whether specific essential fatty acid levels affected the development of OA.

METHODS

We studied participants from the Multicenter Osteoarthritis Study (MOST) at risk of developing knee OA. As part of MOST, participants were asked repeatedly about knee pain, and knee radiographs and magnetic resonance images (MRIs) were obtained. Using baseline fasting samples, we analyzed serum fatty acids with standard assays. After excluding participants with baseline OA, we defined two sets of cases based on their status through 60 months' follow-up: those developing incident radiographic OA and those developing incident symptomatic OA (knee pain and radiographic OA). Controls did not develop these outcomes. Additionally, we examined worsening of MRI cartilage damage and synovitis and worsening knee pain and evaluated the number of hand joints affected by nodules. In regression models, we tested the association of each OA outcome with levels of specific n-3 and n-6 fatty acids, adjusting for age, sex, body mass index, education, physical activity, race, baseline pain, smoking, statin use, and depressive symptoms.

RESULTS

We studied 363 cases with incident symptomatic knee OA and 295 with incident radiographic knee OA. The mean age was 62 years (59% women). We found no associations of specific n-3 fatty acid levels, including EPA, or of n-6 fatty acid levels with incident OA (eg, for incident symptomatic knee OA, the odds ratio per SD increase in EPA was 1.0 [95% confidence interval 0.87-1.17]). Results for other OA outcomes also failed to suggest a protective effect of specific n-3 fatty acids with OA outcomes.

CONCLUSION

We found no association of serum levels of EPA or of other specific n-3 fatty acids or n-6 fatty acids with risk of incident knee OA or other OA outcomes.

Beta-Cryptoxanthin Supplementation Protects Against Liver Cancer Progression and Correlates With Altered Targeted and Untargeted Metabolomic Profiles in Mice

Objectives

Nonalcoholic fatty liver disease (NAFLD)-associated hepatocellular carcinoma (HCC) is expected to increase globally in the upcoming years. Diets high in refined carbohydrates and added sugars (HRCD) have been linked to NAFLD progression. Previous studies have demonstrated that retinoids possess anti-tumorigenic properties, yet less is known about whether upstream provitamin A carotenoids exhibit similar characteristics. We recently demonstrated that dietary beta-cryptoxanthin (BCX), a provitamin A carotenoid, decreased NAFLD severity and HCC progression in diethylnitrosamine (DEN)-initiated, high refined carbohydrate diet (HRCD)-fed mice. In this study, we evaluated the effects of dietary BCX supplementation on modulating plasma biomarkers, hepatic vitamin A status, and plasma metabolomic profiles in our DEN-initiated, HRCD-promoted model of HCC.

Methods

Male, six-week-old C57BL/6J mice were injected with DEN (25 mg/kg BW) and a fed a HRCD (66.5% carbs including sucrose) with or without BCX supplementation (10 mg/kg diet) for 24 weeks. Using plasma samples, we performed metabolomics using our UHPLC-QTOF-MS platform, a targeted Biocrates MxP Quant 500 kit, and a complimentary untargeted analysis of phospholipids from the METLIN database to identify metabolites which correlate with primary outcomes. Hepatic vitamin A levels were determined via HPLC.

Results

Compared to HRCD-fed, DEN-injected mice, mice fed BCX displayed significantly lower tumor burden and steatosis, higher hepatic vitamin A status, and lower plasma levels of alanine transaminase (ALT) and lactate dehydrogenase (LDH). Moderate negative correlations were also identified amongst hepatic vitamin A levels and primary outcomes, such as HCC tumor number, steatosis score, and relevant biomarkers. Our metabolomics data showed significant modulations in metabolites with BCX treatment from phosphatidylcholine, sphingomyelin, ceramide, bile acid, and other phospholipid classes.

Conclusions

BCX supplementation significantly reduced HCC severity, increased hepatic vitamin A status, reduced plasma levels of ALT and LDH, and altered several lipid-related classes of metabolites, thus supporting a chemopreventive potential for BCX against HRCD-promoted HCC development.

Funding Sources

USDA/ARS and NIFA/AFRI.

Ablation of Carotenoid Cleavage Enzymes BCO1 & BCO2 Alters Gut Microbial and Plasma Metabolomic Profiles in High Refined Carbohydrate Diet-Fed Mice

Objectives

β-Carotene-15,15′-oxygenase (BCO1) and β-carotene-9′,10′-oxygenase (BCO2) cleave carotenoids to form vitamin A or apo-carotenoid species. Beyond these roles, BCO1 and BCO2 have been implicated in modulating lipid, cholesterol, and oxidative stress-related processes, yet less is known about their combined influence on shaping gut microbial and plasma metabolic profiles. Current intake of refined carbohydrates and added sugars exceeds the recommendations within the Dietary Guidelines for Americans, which may contribute to the development of nonalcoholic fatty liver disease (NAFLD). In the present study, we aimed to uncover whether mice with systemic ablation of BCO1-/-/BCO2-/- (DKO) display distinctive phenotypes in response to a high refined carbohydrate diet (HRCD) model of NAFLD.

Methods

Male, six-week-old C57BL/6J wild type mice (WT) and DKO mice were fed a chow diet or a HRCD (66.5% carbs including sucrose) for 24 weeks. We used fecal and plasma samples to respectively perform 16S rDNA sequencing, and both targeted and untargeted metabolomics using our UHPLC-QTOF-MS platform, a targeted Biocrates MxP Quant 500 kit, and a complimentary untargeted analysis of phospholipids from the METLIN database. Data were analyzed using QIIME2-DEseq2, MetaboAnalyst 5.0, MassHunter Qualitative Analysis, and MicrobiomeAnalyst.

Results

HRCD-fed WT and DKO mice developed similar levels of hepatic steatosis although DKO mice had significantly higher hepatic levels of malondialdehyde (MDA). Interestingly, in both chow-fed and HRCD-fed DKO mice, plasma adiponectin and hepatic bile acids were significantly lower compared to respective WT groups. Our metabolomics data revealed that DKO mice displayed significant alterations in ceramide, cholesterol ester, triglyceride, and phospholipid classes under both chow and HRCD conditions. Additionally, when compared to HRCD-fed WT mice, HRCD-fed DKO mice displayed significantly reduced alpha diversity and possessed significant compositional differences based on Bray Curtis dissimilarity measures.

Conclusions

BCO1/BCO2 DKO mice display altered metabolomic and gut microbial profiles. Carotenoid cleavage enzymes affect diverse physiological processes, which involve lipid metabolism and the gut microbiome.

Funding Sources

USDA/ARS and NIFA/AFRI.

Serum non-esterified fatty acid levels and hip fracture risk: The Cardiovascular Health Study

Among elderly participants from the Cardiovascular Health Study, we found that non-esterified trans fatty acid levels had a significant prospective association with hip fracture risk. Other non-esterified fatty acid classes were not associated with hip fracture risk.

INTRODUCTION

Serum non-esterified fatty acids (NEFAs) are bioactive metabolic intermediates that can be taken up by bone tissue. Their associations with hip fracture risk have not been previously examined.

METHODS

Thirty-five individual NEFAs in five classes (saturated [SFA], mono-un-saturated [MUFA], poly-unsaturated n-6 and n-3 [PUFA], and trans-FA) were measured in Cardiovascular Health Study participants (n = 2139, mean age 77.8 years) without known diabetes. The multivariable associations of NEFA levels with hip fracture risk were evaluated in Cox hazards models.

RESULTS

We documented 303 incident hip fractures during 11.1 years of follow-up. Among the five NEFA classes, total trans FA levels were positively associated with higher hip fracture risk (HR 1.17 [95% CI, 1.04, 1.31; p = 0.01] per one standard deviation higher level). The SFA lignoceric acid (24:0) was positively associated with higher risk (HR 1.09 [1.04, 1.1]; p < 0.001), while behenic (22:0) and docosatetraenoic (22:4 n6) acids were associated with lower risk (HR 0.76 [0.61, 0.94]; p = 0.01; 0.84 [0.70, 1.00]; p = 0.05, respectively).

CONCLUSION

Total plasma trans NEFA levels are related to hip fracture risk, suggesting an unrecognized benefit of their systematic removal from food. Novel associations of individual NEFAs with hip fracture risk require confirmation in other cohort studies.

Fatty acids and osteoarthritis: the MOST study

OBJECTIVE

Inflammation worsens joint destruction in osteoarthritis (OA) and aggravates pain. Saturated and n-6 fatty acids (FAs) increase, whereas n-3 FAs reduce inflammation. We examined whether FA levels affected the development of OA.

DESIGN

We studied participants from the Multicenter Osteoarthritis study (MOST) at risk of developing knee OA. After baseline, repeated knee x-rays and MRIs were obtained and knee symptoms queried through 60 month follow-up. Using baseline fasting samples, serum FAs were analyzed with standard assays. After excluding participants with baseline OA, we defined two sets of cases: those developing radiographic OA and those developing symptomatic OA (knee pain and radiographic OA). Controls did not develop these outcomes. Additionally, we examined worsening of MRI cartilage loss and synovitis and of knee pain using WOMAC and evaluated the number of hand joints affected by nodules. In regression models, we tested the association of each OA outcome with levels of saturated, n-3 and n-6 FAs adjusting for age, sex, BMI, education, race, baseline pain and depressive symptoms.

RESULTS

We studied 260 cases with incident symptomatic and 259 with incident radiographic OA. Mean age was 61 years (61% women). We found no signficant nor suggestive associations of FA levels with incident OA (e.g., for incident symptomatic OA, OR per s.d. increase in n-3 FA 1.00 (0.85, 1.18) nor with any OA outcome in knee or hand.

CONCLUSION

Despite previously described effects on systemic inflammation, blood levels of FAs were not associated with risk of later knee OA or other OA outcomes.

Spillover Effects of a Family-Based Childhood Obesity Intervention on Parental Nutrient Biomarkers and Cardiometabolic Risk Factors

Objectives

To evaluate the impact of a family-based weight management intervention for children with overweight/obesity on parental nutrient biomarker concentrations and cardiometabolic risk factors (CMRF).

Methods

Secondary analysis from a randomized-controlled, parallel-arm clinical trial. Families were recruited from a largely Hispanic population and assigned to either Standard Care (SC; American Academy of Pediatrics overweight/obesity recommendations) or Standard Care + Enhanced Program (SC + EP; eight skill-building cores, subsequent monthly support sessions, targeted diet/physical activity strategies). Nutrient biomarkers (plasma carotenoids and fat soluble vitamins; red blood cell [RBC] fatty acid profiles) and CMRF (BMI, blood pressure, plasma glucose, insulin, lipid profile, inflammatory markers and adipokine concentrations) were measured in archived samples collected from the parents at baseline and at the end of the 1-year intervention.

Results

Parents of children in both groups (SC = 106; SC + EP = 99) had significantly lower total SFA (−3%) and trans fatty acid (−14%), and higher MUFA (2%), PUFAn-6 (2%), PUFAn-3 (7%) and beta-carotene (20%) concentrations, indicative of decreased partially-hydrogenated fat and increased vegetable oil, fish and fruit/vegetable intake, respectively. In both groups, there were significant reductions in inflammatory markers (hsCRP [−21%], TNFα [−19%] and IL-6 [−19%]), but not in BMI, blood pressure or lipid profile. Parents with children assigned to the SC + EP group had additional improvements in serum insulin (−6%) and leptin (−1.3%) concentrations. Using multiple linear regression models adjusted for sex, age, group, baseline BMI, and baseline CMRF values, improvements in circulating inflammatory and glucose metabolism markers, and adipokine concentrations were associated with higher carotenoid and PUFAn-3 (specifically 20:5n-3), and lower SFA and trans fatty acid concentrations, at the end of the 1-year intervention.

Conclusions

These results suggest that a family-based childhood obesity intervention can spill over to parents, resulting in apparent healthier dietary shifts that are associated with modest improvements in some CMRF.

Funding Sources

NIH, NIDDK, USDA.

Serum Fasting Non-esterified Fatty Acids and Carotid Artery Intima-Media Thickness in Older Adults: The Cardiovascular Health Study

Objectives

Carotid artery intima-media thickness (CIMT) has been used as an early indicator of subclinical atherosclerosis. Multiple studies have identified significant associations between plasma total non-esterified fatty acid (NEFA) concentrations and risk factors associated with subclinical atherosclerosis. However, the relationship between CIMT and serum NEFA is less clear. We hypothesized fasting serum total, individual saturated, and trans NEFA are positively associated with, and individual monounsaturated, n-6 polyunsaturated (PUFA) and n-3 PUFA NEFA are inversely associated with, CIMT.

Methods

We investigated the associations between fasting serum NEFA, and CIMT assessed in 1998–1999 among Cardiovascular Health Study (CHS) participants (N = 1,569) not taking anti-diabetic medication. A total of 35 individual NEFAs were measured in stored specimens from 1996–1997 using gas chromatography. CIMT was determined using ultrasound images, and was defined as the sum of the maximum common CIMT at the far wall divided by its standard deviation (SD) and the maximum internal CIMT at the far wall divided by its SD. At baseline, mean age was 77.3 ± 4.2, body mass index (BMI) was 26.8 ± 4.3 and 64% were female. Associations were assessed by linear regression, with adjustments for other individual NEFAs, age, sex, race, field center, education, smoking, BMI, physical activity, alcohol consumption, eGFR, serum albumin, hyperglycemia, hypertension, use of anti-hypertensive, statin, and other lipid-lowering drugs.

Results

In adjusted models per SD increment, linoelaidic acid (trans18:2) was positively associated with CIMT [β (95% confidence interval): 10.4 (0.99, 19.8), P = 0.03], and α-linolenic acid (18:3n-3) was marginally associated with lower CIMT [−21.2 (−42.6, 0.2), P = 0.05]. No significant associations were observed between total NEFAs or any other individual NEFAs (SFA, MUFA, and n-6 PUFA) and CIMT.

Conclusions

In this large community-based cohort of older adults, higher concentration of linoelaidic acid was positively associated with CIMT, suggesting the importance of partially hydrogenated fat in the development of subclinical atherosclerosis in older adults. Overall, however, serum fasting NEFAs were largely unrelated to subclinical atherosclerosis in CHS participants.

Funding Sources

NIH, NHLBI, USDA.

Serum Non-esterified Fatty Acids and Risk of Incident Stroke in Older Adults: The Cardiovascular Health Study

Objectives

Significant associations between plasma total non-esterified fatty acid (NEFA) concentrations and incident ischemic stroke have been reported in some but not all prospective cohort studies. Given the functional and structural diversity among circulating NEFA, the association of individual or sub-groups of circulating NEFAs may provide additional insight into their relationship with incident stroke. We hypothesized fasting serum monounsaturated, n-6 polyunsaturated (PUFA) and n-3 PUFA NEFA are inversely associated, and saturated and trans NEFA are positively associated with incident stroke.

Methods

We analyzed the incidence of stroke among Cardiovascular Health Study (CHS) participants who were free of stroke in 1996–1997 (baseline) and had an archived fasting serum sample (N = 2028). At baseline, mean age was 77.8 ± 4.5, body mass index (BMI) was 26.7 ± 4.4 and 61% were female. A total of 38 individual NEFAs were measured using gas chromatography. Cox regression was used to evaluate the association of individual and 5 sub-group (saturated, monounsaturated, n-6 PUFA, n-3 PUFA and trans) NEFAs with incident stroke, adjusting for age, sex, race and field center (model 1); model 1 covariates plus serum albumin, smoking, education, physical activity, alcohol consumption, eGFR, BMI, aspirin use, waist circumference, hypertension, prevalent diabetes and total serum cholesterol concentration (model 2).

Results

A total of 338 cases of incident stroke occurred during median follow-up of 10.5 years. In the fully adjusted model 2, individuals in the highest quartile of serum 16:1n-7 had a 56% higher risk of stroke (quartiles 4 versus 1, hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.08–2.25; P-trend = 0.02); highest quartile of total n-6 PUFA NEFA had a 40% higher risk (HR, 1.40; 95% CI, 0.99–1.98; P-trend = 0.03); and highest quartile of 20:3n-6 had a 53% higher risk (HR, 1.53; 95% CI, 1.09–2.14; P-trend = 0.01). No significant associations were observed between saturated, n-3 PUFA, and trans NEFAs with incident stroke.

Conclusions

These data suggest a positive association between fasting serum 16:1n-7, 20:3n-6 and total n-6 PUFA NEFAs with incident stroke in CHS participants. No significant associations were observed for the other individual or sub-groups of NEFAs.

Funding Sources

NIH and USDA.

Effects of EPA and DHA Supplementation on Plasma Specialized Pro-resolving Lipid Mediators and Blood Monocyte Inflammatory Response in Subjects with Chronic Inflammation (OR29-01-19)

Objectives

The role of n-3 fatty acid-derived specialized pro-resolving mediators (SPMs), including the novel docosapentaenoic acid (DPA) products, in reducing inflammation in humans has not been determined. We evaluated the differential effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on plasma SPMs and the resulting impact on the inflammatory response of peripheral blood monocytes.

Methods

In a randomized, controlled, crossover trial, 21 subjects (9 men and 12 women, 50–75 y) with chronic inflammation (C-reactive protein > 2 µg/mL) entered a 4-week lead-in control phase (high oleic sunflower oil, 3 g/d) and then two sequential 10-week supplementation phases with pure EPA or DHA (3 g/d each), separated by a 10-week washout phase. Plasma phospholipid (PL) fatty acid composition and SPMs, including their precursors, were measured at the end of each phase. Following lipopolysaccharides (LPS) stimulation, the inflammatory response of blood monocytes was assessed by inflammatory gene expression.

Results

EPA increased PL EPA (P < 0.001) and plasma concentrations of 18-HEPE, the precursor of the E-series resolvins (RvEs) (P < 0.001). The increase in plasma 18-HEPE concentrations, was associated with the increase in PL EPA (β = 14.9 pg/ml, P < 0.01). However, RvEs were undetectable. EPA increased PL DPA (P < 0.001) but not DPA-derived SPMs. DHA increased PL DHA and plasma concentrations of 17-HDHA and 14-HDHA, the precursors of DHA-derived SPMs (P < 0.001). DHA also significantly increased PL EPA and 18-HEPE (P < 0.001), suggesting some DHA retroconversion to EPA. Interestingly, DHA lowered PL DPA (P < 0.001) but increased the DPA-derived SPMs RvD5n-3 DPA and MaR1n-3 DPA (P < 0.001). In monocytes, while both EPA and DHA lowered the LPS-induced expression of TNFA(P < 0.03 and P < 0.001, respectively), TNFA expression was inversely correlated with plasma concentrations of MaR1n-3 DPA (ρ = −0.32, P < 0.04).

Conclusions

Relative to EPA, DHA supplementation increases a broader range of SPMs, with EPA and DHA differentially affecting PL DPA and DPA-derived SPMs. Plasma concentrations of MaR1n-3 DPA following EPA and DHA supplementation are associated with an attenuated inflammatory response in blood monocytes, suggesting a potential role of this SPM in reducing inflammation in humans.

Funding Sources

Funded by USDA/NIFA and Cohn Student Award.

Supporting Tables, Images and/or Graphs

Dietary Patterns Differentially Affect Microbiome Composition and Function in a Porcine Model of Obesity-related Metabolic Disorder (OR23-04-19)

Objectives

To determine the impact of two isocaloric diets containing (38% ,15% and 47% energy from fat, protein and carbohydrate, respectively): Western diet (WD) rich in saturated fat, refined carbohydrate, low in fiber and high in cholesterol, and a heart healthy diet (HHD) rich in unsaturated fat, unrefined carbohydrate, fruits/vegetables, high in fiber and low in cholesterol, on the composition and function of the gut microbiome

Methods

Thirty-Ossabaw pigs were fed WD or HHD diets with half within each group therapeutically treated with statin (atorvastatin [Lipitor]). The fecal microbiome was analyzed one and six months after dietary intervention by 16S rRNA sequencing and metagenomic function was empirically inferred

Results

Genus diversity was transiently affected with a reduced Shannon Diversity index one month after feeding the WD or HHD (FDR P < 0.05) with no change between groups at 6 months. Bacterial communities were clustered and separated by diet independent of gender and separated by treatment with statin in the HHD only. Verrucomicrobiaceae (Akkermansia) and Methanobacteriales (Methanobrevibacter) were increased in pigs as early as one month after feeding the HHD, as was Clostridiales and Bifidobacterium (associated with optimal intestinal health). There was an enrichment of Proteobacteria (Succinivibrionaceae, Desulfovibrionaceae) in pigs fed the WD. Additional members of the Firmicutes phylum were detected. Diet-dependent associations (all P < 0.05) were identified between Lachnospiraceae members and early host dyslipidemia, inflammation, and atheromatous lesions in the left anterior descending proximal (LAD) and LAD/Left circumflex (LCX) bifurcation six months post-intervention.

Conclusions

These data document for the first time a distinctive bacterial profile in Ossabaw pigs with a diet-induced dyslipidemia and early stage atherosclerosis. Taken together these results represent a new model to examine mechanistic pathways of dietary patterns and/or drug interactions and its effect on modulating microbiome in developing atherosclerosis.

Funding Sources

USDA project 8040-51530-056-00 and Inter Agency USDA Agreement 588-1950-9-001 between BHNRC and Jean Mayer USDA-HNRCA

Eicosapentaenoic acid prevents and reverses insulin resistance in high-fat diet-induced obese mice via modulation of adipose tissue inflammation

We investigated the effects of eicosapentaenoic acid (EPA) on prevention (P) and reversal (R) of high saturated-fat (HF) diet-induced obesity and glucose-insulin homeostasis. Male C57BL/6J mice were fed low-fat (LF; 10% energy from fat), HF (45% energy from fat), or a HF-EPA-P (45% energy from fat; 36 g/kg EPA) diet for 11 wk. A 4th group was initially fed HF for 6 wk followed by the HF-EPA-R diet for 5 wk. As expected, mice fed the HF diet developed obesity and glucose intolerance. In contrast, mice fed the HF-EPA-P diet maintained normal glucose tolerance despite weight gain compared with the LF group. Whereas the HF group developed hyperglycemia and hyperinsulinemia, both HF-EPA groups (P and R) exhibited normal glycemia and insulinemia. Further, plasma adiponectin concentration was lower in the HF group but was comparable in the LF and HF-EPA groups, suggesting a role of EPA in preventing and improving insulin resistance induced by HF feeding. Further analysis of adipose tissue adipokine levels and proteomic studies in cultured adipocytes indicated that dietary EPA supplementation of HF diets was associated with reduced adipose inflammation and lipogenesis and elevated markers of fatty acid oxidation. In C57BL/6J mice, EPA minimized saturated fat-induced insulin resistance and this is in part mediated by its effects on fatty acid oxidation and inflammation.

Validity of estimated dietary eicosapentaenoic acid and docosahexaenoic acid intakes determined by interviewer-administered food frequency questionnaire among older adults with mild-to-moderate cognitive impairment or dementia

Epidemiologic research is increasingly being focused on elderly persons, many of whom exhibit mild-to-moderate cognitive impairment. This presents a challenge for collection and interpretation of self-reported dietary data. There are few reports on the impact of cognitive function and dementia on the validity of self-reported dietary intakes. Using plasma phospholipid fatty acid profiles as a biomarker of intake, the authors assessed the validity of an interviewer-administered food frequency questionnaire (FFQ) to estimate intakes of 2 marine-based omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), among 273 community-dwelling adults aged > or =60 years participating in the Nutrition, Aging, and Memory in Elders Study (Boston, Massachusetts, 2002-2008). Age- and energy-adjusted Pearson correlation coefficients for correlations between dietary intakes and plasma phospholipids were consistent across categories of high and low cognitive function (r = 0.48), based on Mini-Mental State Examination score, and were similar across clinically diagnosed categories of normal functioning (r = 0.49), mild cognitive impairment (r = 0.45), and dementia (r = 0.52). The FFQ ranked 78% of subjects to within 1 quartile of their plasma phospholipid EPA + DHA quartile. This frequency was consistently high across all cognitive categories. With interviewer administration, this FFQ seems to be a valid method of assessing dietary EPA + DHA intake in older adults with mild-to-moderate cognitive impairment.