Effects of omega-3 polyunsaturated fatty-acid supplementation on neuropathic pain symptoms and sphingosine levels in Mexican-Americans with type 2 diabetes Alfonso M Durán,1 Lorena M Salto,1 Justin Câmara,1 Anamika Basu,1 Ivette Paquien,1 W Lawrence Beeson,1,2 Anthony Firek,3 Zaida Cordero-MacIntyre,1,2 Marino De León1 1Center for Health Disparities and Molecular Medicine, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA; 2Center for Nutrition, Healthy Lifestyle and Disease Prevention, School of Public Health, Loma Linda University, Loma Linda, CA, USA; 3Comparative Effectiveness and Clinical Outcomes Research Center, Riverside University Health System Medical Center, Moreno Valley, CA, USA Purpose: To determine whether dietary supplementation with omega-3 polyunsaturated fatty acids (PUFAs) reduces neuropathic pain symptoms in Mexican-Americans with type 2 diabetes.Methods: Forty volunteers with type 2 diabetes enrolled in the “En Balance-PLUS” program, which provided weekly nutrition–diabetes education and daily supplementation with 1,000 mg docosahexaenoic acid (DHA)–200 mg eicosapentaenoic acid over 3 months. The study assessed self-reported neuropathic pain symptoms pre/postintervention using the short-form McGill Pain Questionnaire (SF-MPQ), monitored clinical laboratory values at baseline and 3 months, and performed baseline and 3-month metabolomic analysis of plasma samples.Results: A total of 26 participants self-reported neuropathic pain symptoms at baseline. After 3 months of omega-3 PUFA supplementation, participants reported significant improvement in SF-MPQ scores (sensory, affective, and visual analogue scale; P<0.001, P=0.012, and P<0.001, respectively). Untargeted metabolomic analysis revealed that participants in the moderate–high SF-MPQ group had the highest relative plasma sphingosine levels at baseline compared to the low SF-MPQ group (P=0.0127) and the nonpain group (P=0.0444). Omega-3 PUFA supplementation increased plasma DHA and reduced plasma sphingosine levels in participants reporting neuropathic pain symptoms (P<0.001 and P<0.001, respectively). Increased plasma DHA levels significantly correlated with improved SF-MPQ sensory scores (r=0.425, P=0.030). Improved SF-MPQ scores, however, did not correlate with clinical/laboratory parameters.Conclusion: The data suggest that omega-3 PUFAs dietary supplementation may reduce neuropathic pain symptoms in individuals with type 2 diabetes and correlates with sphingosine levels in the plasma. Keywords: lipotoxicity, painful diabetic neuropathy, health disparities, community intervention, neuroprotection, Latinos

The alanine to threonine amino acid substitution at codon 54 (Ala54Thr) of the intestinal fatty acid binding protein (FABP2) has been associated with elevated levels of insulin and blood glucose as well as with dyslipidemia. The aim of this study was to characterize the effect of this FABP2 polymorphism in Mexican-Americans with type 2 diabetes (T2D) in the context of a three-month intervention to determine if the polymorphism differentially modulates selected clinical outcomes. For this study, we genotyped 43 participant samples and performed post-hoc outcome analysis of the profile changes in fasting blood glucose, HbA1c, insulin, lipid panel and body composition, stratified by the Ala54Thr polymorphism. Our results show that the Thr54 allele carriers (those who were heterozygous or homozygous for the threonine-encoding allele) had lower HDL cholesterol and higher triglyceride levels at baseline compared to the Ala54 homozygotes (those who were homozygous for the alanine-encoding allele). Both groups made clinically important improvements in lipid profiles and glycemic control as a response to the intervention. Whereas the Ala54 homozygotes decreased HDL cholesterol in the context of an overall total cholesterol decrease, Thr54 allele carriers increased HDL cholesterol as part of an overall total cholesterol decrease. We conclude that the Ala54Thr polymorphism of FABP2 modulates HDL cholesterol in Mexican-Americans with T2D and that Thr54 allele carriers may be responsive in interventions that include dietary changes.

Despite the evidence that complicated rheumatic diseases are more prevalent and severe in ethnic minorities, rheumatology research is afflicted with inadequate patient representation. It is lacking in ethnic and socioeconomic diversity. The objective of this study is to identify barriers to enrollment in rheumatology research and propose possible solutions to overcome these barriers. In this study, 184 patients from two rheumatology clinics (Safety Net clinic, a university-based clinic) were surveyed for concerns regarding participation in clinical research. Patients were asked to rank their top five of eight concerns. Data were then stratified by self-reported ethnicity and clinic site to determine ranking differences in both groups. Fear of risks associated with clinical research was ranked as the primary barrier in all ethnicities. More non-Hispanic Whites (NHW) (24.4%) ranked work responsibilities as a primary barrier compared to Hispanics (10%). Fear of discovering a serious illness as a primary barrier was more frequent at the Safety Net clinic (25%) compared to the university-based clinic (6.3%) and ranked more frequently in the top five in Hispanics compared to NHW. Fears associated with research risks, work responsibilities, and fear of discovering a serious illness were the top-ranked barriers to enrollment in research among patients. However, differences in rankings between ethnicities and clinic sites were identified. This sheds light on the importance of health literacy and the responsibility of researchers in addressing gaps in communication while acknowledging potential cultural components that warrant further investigation.

Purpose. En Balance, a culturally sensitive diabetes education program, improves glycemic control in Hispanics with type 2 diabetes. The program emphasized diet, physical activity, and other factors important for glycemic control. However, the individual contributions of these education factors are unclear. The purpose of this study is to assess the contribution of physical activity to the success of En Balance in improving the health of Mexican Americans with type 2 diabetes. Methods. A retrospective study was conducted with plasma samples collected pre- and post-3-month study. Samples from 58 (18 males and 40 females) Hispanic subjects with type 2 diabetes were analyzed for the concentration of kynurenines, known to decrease in response to exercise. After three months, health outcomes for the active group (decreased kynurenines) and the rest of the cohort were evaluated by paired Wilcoxon signed-rank test. Results. Half of the subjects had increased kynurenine levels at the end of the educational program. We found that the subjects in the active group with decreased kynurenine concentrations displayed statistically greater improvements in fasting blood glucose, A1C, cholesterol, and triglycerides despite weight loss being higher in the group with increased kynurenine concentrations. Conclusions. En Balance participants with decreased kynurenine levels had significantly improved glycemic control. These data suggest that physical activity significantly contributes to the success of the En Balance education program. This analysis indicates that diabetes public health educators should emphasize the benefit of physical activity on glycemic control even in the absence of major weight loss.