Adipose Tissue Plasticity in Response to Pathophysiological Cues: A Connecting Link between Obesity and Its Associated Comorbidities

Abstract

Adipose tissue (AT) is a remarkably plastic and active organ with functional pleiot-ropism and high remodeling capacity. Although the expansion of fat mass, by defini-tion, represents the hallmark of obesity, the dysregulation of the adipose organ emerges as the forefront of the link between adiposity and its associated metabolic and cardio-vascular complications. The dysfunctional fat displays distinct biological signatures, which include enlarged fat cells (i.e., adipocyte hypertrophy), low-grade inflammation, impaired redox homeostasis, and cellular senescence. While these events are orches-trated in a cell-type, context-dependent and temporal manner, the failure of the adipose precursor cells to form new mature adipocytes appears the main instigator of the adi-pose dysregulation, which, ultimately, poses a deleterious milieu either by promoting ectopic lipid overspill in non-adipose targets (i.e., lipotoxicity) or by inducing an al-tered secretion of different adipose-derived hormones (i.e., adipokines and lipokines). This novel paradigm (“expandability hypothesis”) challenges and extends previous “adipocentric view”, which implies a reduced plasticity of the adipose organ at the nexus between “unhealthy” fat expansion and the development of obesity-associated comorbidities. In this review, we will briefly summarize the potential mechanisms by which adaptive changes to variations of energy balance may impair adipose plasticity and promote fat organ dysfunction. We will also highlight the conundrum with the perturbation of the adipose microenvironment and the development of cardio-metabolic complications by focusing on adipose lipoxidation and cellular senescence. Finally, we discuss the sci-entific rationale for proposing adipose organ plasticity as a target to curb/prevent adi-posity-linked cardio-metabolic complications.