Accumulation and Changes in Composition of Collagens in Subcutaneous Adipose Tissue After Bariatric Surgery

• Published in: The journal of clinical endocrinology and metabolism Vol. 101; no. 1; pp. 293 - 304
• Main Authors: Liu, Yuejun, Aron-Wisnewsky, Judith, Marcelin, Geneviève, Genser, Laurent, Le Naour, Gilles, Torcivia, Adriana, Bauvois, Brigitte, Bouchet, Sandrine, Pelloux, Véronique, Sasso, Magali, Miette, Véronique, Tordjman, Joan, Clément, Karine
• Format: Journal Article
• Language: English
• Published: United States Endocrine Society 01.01.2016; Copyright by The Endocrine Society; Oxford University Press
• Subjects: Adipose tissue; Adult; Bariatric Surgery; Biopsy; Body Composition; Body fat; Body weight loss; CD163 antigen; Collagen; Collagen (type I); Collagen - metabolism; Cross-linking; Elasticity Imaging Techniques; Endocrinology and metabolism; Enzyme inhibitors; Enzymes; Extracellular matrix; Extracellular Matrix - metabolism; Extracellular Matrix Proteins - metabolism; Female; Gastrointestinal surgery; Human health and pathology; Humans; Life Sciences; Lysyl oxidase; Macrophages; Macrophages - metabolism; Male; Metabolism; Middle Aged; Obesity; Obesity, Morbid - metabolism; Obesity, Morbid - surgery; Physical characteristics; Subcutaneous Fat - metabolism; Surgery; Transcriptome; Transcriptomics; Vascular Stiffness; Weight Loss; weight loss; collagen accumulation; fibrosis; cross-linking; adipose tissue remodeling
• ISSN: 0021-972X; 1945-7197; 1945-7197
• DOI: 10.1210/jc.2015-3348

Context:Extracellular matrix (ECM) in sc adipose tissue (scAT) undergoes pathological remodeling during obesity. However, its evolution during weight loss remains poorly explored.Objective:The objective of the investigation was to study the histological, transcriptomic, and physical characteristics of scAT ECM remodeling during the first year of bariatric surgery (BS)-induced weight loss and their relationships with metabolic and bioclinical improvements.Design, Setting, Patients, and Interventions:A total of 118 morbidly obese candidates for BS were recruited and followed up during 1 year after BS.Main Outcome Measures:scAT surgical biopsy and needle aspiration as well as scAT stiffness measurement were performed in three subgroups before and after BS. Fourteen nonobese, nondiabetic subjects served as controls.Results:Significantly increased picrosirius-red-stained collagen accumulation in scAT after BS was observed along with fat mass loss, despite metabolic and inflammatory improvements and undetectable changes of scAT stiffness. Collagen accumulation positively associated with M2-macrophages (CD163+ cells) before BS but negatively afterward. Expression levels of genes encoding ECM components (eg, COL3A1, COL6A1, COL6A2, ELN), cross-linking enzymes (eg, lysyl oxidase [LOX], LOXL4, transglutaminase), metalloproteinases, and their inhibitors were modified 1 year after BS. LOX expression and protein were significantly decreased and associated with decreased fat mass as well as other cross-linking enzymes. Although total collagen I and VI staining decreased 1 year after BS, we found increased degraded collagen I and III in scAT, suggesting increased degradation.Conclusions:After BS-induced weight loss and related metabolic improvements, scAT displays major collagen remodeling with an increased picrosirius-red staining that relates to increased collagen degradation and importantly decreased cross-linking. These features are in agreement with adequate ECM adaptation during fat mass loss.