Impact of Almond Consumption on Adipose Tissue Gene Expression Profiles in Adults With Obesity

Objectives: Investigating the impact of dietary interventions on adipose tissue gene expression can reveal underlying mechanisms, paving the way for targeted interventions against obesity and metabolic disorders. Hence, this study aimed to investigate the effects of consuming almonds, a nutrient-rich food, for 6 weeks on the expression of genes involved in inflammatory and metabolic processes in the subcutaneous adipose tissue (SAT) of adults with obesity. Methods: Adults (age: 30-45 years, BMI: 30-45 kg/m2, N=30) were randomly assigned to consume either almonds (2 oz./d, n = 15) or an isocaloric control snack of cookies (325 kcal/d, n = 15) daily for 6 weeks, as part of an ongoing study. SAT samples were collected before and 6 weeks after the intervention. Primers for 19 genes related to inflammation, autophagy, and metabolism were designed with Primer3 and synthesized by Millipore Sigma. RNA was extracted from SAT using the Trixol-chloroform-ethanol method and quantified via NanoDrop. cDNA was synthesized from 100 ng/μl RNA and analyzed by RT-qPCR using a mix of cDNA, SYBR, primer, and RNAse-free water. Gene expression was quantified by normalizing the Ct values of target genes to beta-actin housekeeping gene (delta Ct). A mixed model analysis was conducted in JMP Pro to test effects of group, time, and group x time interaction effects on delta Ct values. When significant main effects were observed, post hoc t-tests with adjustments for multiple comparisons were conducted. Results: Significant group x time interaction effects were found for relative expression of IL-10, IL-1 beta, TNF-alpha, leptin receptor, PPAR-alpha, ADRB1, ATG12, and UCP2 genes in SAT (group x time effect, P< 0.05). Almond consumption significantly increased relative gene expression of IL-10, IL-1 beta, TNF-alpha, leptin receptor, PPAR-alpha, ATG12, and UCP2, and decreased expression of ADRB1 over 6 weeks (P< 0.05 for baseline vs. week 6 in almond group), suggesting alterations in inflammatory signaling, metabolic, and energy expenditure processes. Moreover, no changes in the expression of those genes were observed in the cookie group over 6 weeks. Conclusions: This preliminary analysis revealed that almond consumption can differentially modulate inflammatory and metabolic processes in SAT, underscoring the impact of diet on SAT physiology in obesity. Funding Sources: Almond Board of California.