Comparative Study of Inflammatory and Oxidative Stress Biomarkers in Different Metabolically Healthy Obesity Phenotypes

Abstract

Aims: Obesity is the major contributor of the metabolic syndrome (MetS), but a unique phenotype of obesity known as metabolically healthy obese (MHO) shows healthier metabolic profile ; however understanding of their biochemical correlates is poorly understood. Obesity is defined by Body mass index (BMI), but controversy exists regarding ethnic-specific BMI cut-offs. The present study used the Asian Indian BMI cut - offs to assess relationships of MHO phenotypes with oxidative stress (OS) and inflammation. Methods: In this case-control study, 299 metabolically-healthy (MH) respondents were divided into four groups as per Asian criteria for obesity: MH non-obese (MHNO), MH overweight (MHOW), MHO and MH severely obese (MHSO ). Their oxidative stress and pro-inflammatory markers were measured. Results: Levels of hydroxyl radicals ( · OH), fluorescent oxidation products (FLOP), MDA, PCO and inflammatory markers CRP, TNF- α , IL-6 were highest in MHSO phenotype followed by the MHO, MHOW and MHNO groups (p > 0.0001), whereas antioxidant markers, CuZn-SOD, catalase, glutathione peroxidase and total antioxidant activity followed the reverse trend. The MHNO and MHOW groups showed significant difference with regard to ( · OH) radicals and FLOP. Moreover, · OH radicals, FLOP and inflammatory markers were significantly correlated to BMI in MHSO and MHO but not in MHNO and MHOW group. Conclusion: The MHO and MHSO phenotype display differences in terms of OS and inflammatory markers at lower BMI cut - offs, indicating that they may be on the way to becoming “ unhealthy ” ob ese. The lower BMI cut-offs proposed by Indian Consensus Group would help in understanding of manifestation of metabolic syndrome.