Inflammatory gene expression in adipose tissue according to diagnosis of anxiety and mood disorders in obese and non-obese subjects

Abstract

Psychiatric disorders have been widely reported to be associated with systemic inflammation upregulation and adiposity. However, there are no data that link adipose tissue inflammation to these mental disorders. The analysis of adipokines and inflammation-related markers in adipose tissue could help to elucidate the potential association between obesity and mental health. An observational study was conducted in samples of patients consisting of non-obese and obese subjects, who were diagnosed with anxiety or mood disorders. Gene expression of adiponectin (ADIPOQ), leptin (LEP) and inflammatory markers (IL6, IL1B, TNF, CCL2, CSF3, ITGAM, and PLAUR) were determined in visceral (VAT) and subcutaneous (SAT) adipose tissues. Our results showed that the gene expression of adipokines and inflammation-related markers was higher in the VAT and SAT of obese subjects compared with non-obese subjects. Regarding mental disorders, all the inflammatory genes in the VAT were significantly higher in non-obese subjects with anxiety or mood disorders than in subjects without mental disorders, except for TNF and ITGAM. Additionally, IL6 expression was significantly lower in SAT. In contrast, obese patients diagnosed with anxiety or mood disorders only showed significantly lower expression levels of IL1B in VAT and ADIPOQ in SAT when compared with obese subjects without mental disorders. These data suggest the potential involvement of VAT inflammation in anxiety and mood disorders, involving complex mechanisms which are strongly affected by obesity.

Figure 1

Gene expression of inflammatory markers altered in the adipose tissue of the non-obese group according to anxiety and mood disorders. Relative mRNA levels of IL1B, IL6, CCL2, CSF3 and PLAUR in visceral adipose tissue and IL6 in the subcutaneous adipose tissue according to ‘mental disorder status’ (A) or ‘type of mental disorder’ (B). Bars are estimated marginal means and 95% CI. *P < 0.05 and **P < 0.01 denotes significant main effect using ANCOVA. (+) P < 0.05, (++) P < 0.01 and (+++) P < 0.001 denotes significant differences compared with the non-MD subgroup. Abbreviations: VAT, visceral adipose tissue; SAT, subcutaneous adipose tissue; Non-MD, non–mental disorder subgroup; A/MD, anxiety/mood disorders subgroup; ANX, anxiety disorders subgroup; MOOD, mood disorders subgroup.

Figure 2

Gene expression of IL-1β and adiponectin in the adipose tissue of the obese group according to anxiety and mood disorders. Relative mRNA levels of IL1B in visceral adipose tissue and ADIPOQ in subcutaneous adipose tissue according to ‘mental disorder status’ (A) or ‘type of mental disorder’ (B). Bars are estimated marginal means and 95% CI. *P < 0.05 and **P < 0.01 and ***P < 0.001 denotes significant main effect using ANCOVA. (+) P < 0.05 and (++) P < 0.01 denotes significant differences compared with the non-AMD subgroup. Abbreviations: VAT, visceral adipose tissue; SAT, subcutaneous adipose tissue; Non-MD, non–mental disorders subgroup; A/MD, anxiety/mood disorders subgroup; ANX, anxiety disorders subgroup; MOOD, mood disorders subgroup.