Enteroendocrine cells: a review of their role in brain–gut communication

Abstract

Background Specialized endoderm derived epithelial cells, i.e. enteroendocrine cells (EECs), are widely distributed throughout the gastrointestinal (GI) tract. EECs form the largest endocrine organ in the body and play a key role in the control of GI secretion and motility, the regulation of food intake, postprandial glucose levels and metabolism. EECs sense luminal content and release signaling molecules that can enter the circulation to act as classic hormones on distant targets, act locally on neighboring cells and on distinct neuronal pathways including enteric and extrinsic neurons. Recent studies have shed light on EEC sensory transmission by showing direct connections between EECs and the nervous system via axon-like processes that form a well-defined neuroepithelial circuits through which EECs can directly communicate with the neurons innervating the GI tract to initiate appropriate functional responses. Purpose This review will highlight the role played by the EECs in the complex and integrated sensory information responses, and discuss the new findings regarding EECs in the brain-gut axis bidirectional communication.

The Importance of the Gastrointestinal Tract in Controlling Food Intake and Regulating Energy Balance

“…4 10 . Recent, transgenic advances have enabled the isolation and characterization of the previously enigmatic EECs.…”

“…19 nervous system and utilizes a wide variety of peptide neurotransmitters in addition to acetylcholine and noradrenaline 10 . Gut hormone secretion is modulated by signals from other EEC populations and from the ENS.…”

Targeting the gut to treat obesity and its metabolic consequences: view from the Chair

“…14 Recent evidence supports the idea that these cells have a central role in the expression of diet-induced obesity and that gut peptides have a critical role in the control of hunger, satiety, glucose metabolism, metabolic and nutrient sensing. 5,14,[17][18][19] The subpopulation of enteroendocrine cells that contain and release serotonin (5-HT) are also involved in the stimulation of propulsive and segmental motility, epithelial secretion and vasodilation, as well as nausea and vomiting, and recent evidence supports a proinflammatory action of enteroendocrine 5-HT. 20 Enteroendocrine cells release their contents basolaterally into the lamina propria where they can enter the mucosal microcirculation and lymphatic systems, and they can interact with the dense innervation that lies beneath the epithelium.…”

“…14 Recent evidence supports the idea that these cells have a central role in the expression of diet-induced obesity and that gut peptides have a critical role in the control of hunger, satiety, glucose metabolism, metabolic and nutrient sensing. 5,14,[17][18][19] The subpopulation of enteroendocrine cells that contain and release serotonin (5-HT) are also involved in the stimulation of propulsive and segmental motility, epithelial secretion and vasodilation, as well as nausea …”

“…15,16 Many of these receptors are localized on enteroendocrine cells in the gut. 17 Enteroendocrine cells are specialized cells scattered throughout the GI epithelium that upon stimulation release a variety of peptides and amines that serve as paracrine mediators, acting locally, and/or hormones, acting via the circulation. 14 Recent evidence supports the idea that these cells have a central role in the expression of diet-induced obesity and that gut peptides have a critical role in the control of hunger, satiety, glucose metabolism, metabolic and nutrient sensing.…”