The Role of Adipose Tissue and Nutrition in the Regulation of Adiponectin

Abstract

Adipose tissue (AT), composed mainly of adipocytes, plays a critical role in lipid control, metabolism, and energy storage. Once considered metabolically inert, AT is now recognized as a dynamic endocrine organ that regulates food intake, energy homeostasis, insulin sensitivity, thermoregulation, and immune responses. This review examines the multifaceted role of adiponectin, a predominant adipokine released by AT, in glucose and fatty acid metabolism. We explore the regulatory mechanisms of adiponectin, its physiological effects and its potential as a therapeutic target for metabolic diseases such as type 2 diabetes, cardiovascular disease and fatty liver disease. Furthermore, we analyze the impact of various dietary patterns, specific nutrients, and physical activities on adiponectin levels, highlighting strategies to improve metabolic health. Our comprehensive review provides insights into the critical functions of adiponectin and its importance in maintaining systemic metabolic homeostasis.

Keywords: adipokines; adiponectin; adipose tissue; cardiovascular disease; dietary interventions; endocrine function; fatty acid metabolism; insulin sensitivity; metabolic diseases; metabolic homeostasis; nutritional therapy; physical activity; type 2 diabetes.

Figure 1

The structure and functions of white, brown, beige, pink, and marrow adipose tissue. Energy storage, endocrine communication, and insulin sensitivity are the main activities that characterize white adipose tissue (WAT). Thermogenesis and energy expenditure instead characterize brown adipose tissue (BAT). Beige adipocytes, present in WAT, also contribute to thermogenesis. Pink adipocytes are formed during pregnancy and lactation and play a role in milk secretion. Medullary adipose tissue (MAT) is located in the bone marrow and participates in local and systemic metabolic processes. This figure illustrates the cellular characteristics and distinct physiological roles of each type of adipose tissue.

Figure 2

Structure, receptors, and function of adiponectin in various organs. Adiponectin, produced by adipose tissue, exists in various forms, such as monomers, trimers, and hexamers. It acts through its receptors, adipoR1 and adipoR2, to influence multiple metabolic processes. Activation of adipoR1 mainly promotes mitochondrial biogenesis and glucose uptake through the AMPK and p38MAPK pathways. AdipoR2 activation is involved in fatty acid oxidation through the PPARα pathway and provides cytoprotective and anti-inflammatory effects through modulation of NF-κB. Collectively, these pathways contribute to the regulation of energy metabolism and inflammatory responses in various tissues, including muscle, liver, kidney, brain, and bone. ↑ indicates an increase or upregulation; ↓ indicates a decrease or downregulation. Abbreviations: CPT1: Carnitine palmitoyltransferase I; eNOS: Endothelial nitric oxide synthase; FoxO1: Forkhead box protein O1; G6Pase: Glucose-6-phosphatase; GLUT-4: Glucose transporter type 4; JAK2: Janus kinase 2; LKB1: Liver kinase B1; NADPH: Nicotinamide adenine dinucleotide phosphate; NFκB: Nuclear factor kappa-light-chain-enhancer of activated B cells; PEPCK: Phosphoenolpyruvate carboxykinase; p38MAPK: p38 mitogen-activated protein kinase; SIRT1: Sirtuin 1.