Endocrine Abstracts

Introduction and aim: Leptin is a hormone that mainly expressed and secreted in adipose tissues and has a number of important effects on regulation of body weight, energy expenditure, and thermogenesis. High intake of n-3 polyunsaturated fatty acids (PUFA) promotes reduced plasma concentration of triacylglycerol, glycerol, and free fatty acids, as well as metabolism of the epididymis. The aim of current study was to examine the association of n-3PUFA on leptin gene expression in visceral and subcutaneous adipose tissue of adults.

Methods: We gathered visceral and subcutaneous adipose tissues during an elective abdominal surgery which have minimal impact on dietary intake form 98 participants aged >19 who were free of diabetes and cancers and without using anti-lipid medication. Before the surgery, a reliable and validated semi-quantitative food frequency questionnaire was completed to assess habitual dietary intake of n-3 PUFA, α-linolenic acid ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Dietary exposures were adjusted for energy by using the residual method. The mRNA expressions of leptin gene in both adipose tissues measured by SYBER-Green real-time quantitative PCR. Multivariable linear regression was performed to assess the association of dietary n-3 PUFA with leptin gene expression. All models were adjusted for age, body mass index(BMI), insulin, and physical activity.

Results: The mean age of participants was 41.6 years and BMI was 33.6 kg/m². Median intake of n-3 PUFA in our study was 2.44 g/day which corresponded to 0.88% of total energy intakes. In visceral fat, leptin mRNA levels were significantly higher compared with subcutaneous adipose tissue. After controlling for confounders, usual intake of dietary n-3 PUFA was negatively associated with leptin gene expression in subcutaneous (β=−0.523, P<0.001) and visceral (β=−0.780, P<0.001) adipose tissues. Moreover, we found a significant inverse association of dietary intake of ALA (β=−0.695, P<0.001) and DHA (β=−0.471, P=0.009) with leptin gene expression in visceral adipose tissue. There was no significant association between leptin gene expression and EPA intake.

Conclusion: The current study illustrated that higher usual dietary n-3 PUFA were negatively associated with leptin gene expression in both adipose tissues independent of BMI, age, insulin, and physical activity. In addition, DHA and ALA had a relationship with leptin mRNA expression, especially in visceral adipose tissue. It seems that habitual intake of n-3 PUFA might affect adipose tissue metabolism through modifying leptin gene expression.