title: Similar degrees of obesity induced by diet or aging cause strikingly different immunologic and metabolic outcomes.
abstract: In obesity, adipose tissue (AT) and liver are infiltrated with Th-1 polarized immune cells, which are proposed to play an important role in the pathogenesis of the metabolic abnormalities of obesity. Aging is also associated with increased adiposity, but the effects of this increase on inflammation and associated metabolic dysfunction are poorly understood. To address this issue, we assessed insulin resistance (IR) andATand liver immunophenotype in aged, lean (AL) and aged, obese (AO) mice, all of whom were maintained on a standard chow diet (11% fat diet) throughout their lives. For comparison, these variables were also assessed in young, lean (YL) and young diet-induced obese mice (41% fat diet,YO). Despite similar body weight and fat accumulation,YOmice were substantially moreIRand had greater liver steatosis compared toAOmice.YOalso had elevated infiltration of macrophages/dendritic cells inATand liver, but these increases were absent inAO Furthermore, liver immune cells ofYOwere more Th-1 polarized thenAO Notably, aging was associated with accumulation of T cells, but this occurred independent of obesity. Together, the data suggest that reduced inflammation inAOunderlies the improved insulin sensitivity and lowered steatosis compared toYO.
authors.affiliation: Division of Pediatric Endocrinology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania.
authors.forename: Kanthi B
authors.initials: KB
authors.lastname: Krishna
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Maja
authors.initials: M
authors.lastname: Stefanovic-Racic
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Dedousis
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Ian
authors.initials: I
authors.lastname: Sipula
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania rmo1@pitt.edu.
authors.forename: Robert M
authors.initials: RM
authors.lastname: O'Doherty
mesh_terms: D000273:Adipose Tissue / Q000276:immunology / Q000378:metabolism; D050154:Adiposity; D000367:Age Factors; D000375:Aging / Q000097:blood / Q000276:immunology; D000818:Animals; D003713:Dendritic Cells / Q000276:immunology; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D005234:Fatty Liver / Q000097:blood / Q000209:etiology* / Q000276:immunology; D016130:Immunophenotyping; D007333:Insulin Resistance; D008099:Liver / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000276:immunology; D008297:Male; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000097:blood / Q000209:etiology* / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D013997:Time Factors
keywords: Aging; immunology; obesity