Energy expenditure regulation via macrophage migration inhibitory factor in obesity and in vitro anti-macrophage migration inhibitory factor effect of Alpinia officinarum Hance extraction.

OBJECTIVE

To compare the resting energy expenditure in different macrophage migration inhibitory factor (MIF) genotypes and to identify the in vitro effects of Alpinia officinarum Hance extract (AOHE) on MIF expression in obese and nonobese persons.

METHODS

In the fasting state, obese and nonobese persons were assessed for the measurement of resting energy expenditure rate (REE) by indirect calorimetry. We compared it with the expected amount ([REE measured by indirect calorimetry / predicted REE according to Harris Benedict equations] x 100). Participants were classified into those with normal REE (≥100) vs those with impaired REE (<100). Body composition was analyzed. Real-time polymerase chain reaction was performed using specific primer pairs for MIF messenger RNA, and β-actin was used as the internal control.

RESULTS

The study included 69 obese and 103 non-obese participants. The proportions of MIF genotypes were slightly different in obese and nonobese participants. However, the proportions of MIF genotypes were significantly different in participants with normal REE and those with low REE. The MIF gene was highly expressed in the obese group compared with MIF expression in the nonobese group. Body fat mass and MIF expression were higher in participants with the GG genotype than in the other genotype groups. MIF expression was inversely associated with REE in both groups (r = -0.36, P = .04). After treatment of peripheral blood mononuclear cells with AOHE, MIF expression differed according to MIF genotype.

CONCLUSIONS

Our results indicate that AOHE is a major modulator of MIF-dependent pathologic conditions in obesity and are consistent with mounting evidence that defines a regulating role for MIF in cytokine production in an inflammatory state in in vitro studies.