Direct evidence of brown adipocytes in different fat depots in children.

Recent studies suggested the persistence of brown adipocytes in adult humans, as opposed to being exclusively present in infancy. In this study, we investigated the presence of brown-like adipocytes in adipose tissue (AT) samples of children and adolescents aged 0 to 18 years and evaluated the association with age, location, and obesity. For this, we analysed AT samples from 131 children and 23 adults by histological, immunohistochemical and expression analyses.

Evidence of early alterations in adipose tissue biology and function and its association with obesity-related inflammation and insulin resistance in children.

Accumulation of fat mass in obesity may result from hypertrophy and/or hyperplasia and is frequently associated with adipose tissue (AT) dysfunction in adults. Here we assessed early alterations in AT biology and function by comprehensive experimental and clinical characterization of 171 AT samples from lean and obese children aged 0 to 18 years. We show an increase in adipocyte size and number in obese compared with lean children beginning in early childhood.

Molecular characteristics of serum visfatin and differential detection by immunoassays.

Context: There are controversial results concerning the association of visfatin with obesity and diabetes. We aimed to characterize molecular features of visfatin, to assess visfatin detection by different immunoassays, and evaluate the association with human obesity and glucose metabolism.

Results: Distinct preparations of human visfatin (recombinant, endogenously expressed from human adipocytes, and overexpressed in COS-7 cells) were readily identified by three currently available immunoassays.