Kolonzellen

Kolonzellen, known in English as colonocytes, are the principal absorptive epithelial cells lining the mucosa of the colon (large intestine) in humans and many mammals. They arise from stem cells located in the crypts of Lieberkühn and migrate upward to form the mature luminal layer, where they differentiate into colonocytes and continuously renew the epithelium.

Structurally, colonocytes are tall columnar cells equipped with microvilli on the apical surface, forming a modest brush border that increases absorptive capacity. They are joined by tight junctions and adherens junctions, which help regulate paracellular transport and maintain the integrity of the mucosal barrier. The colon epithelium also contains mucus-producing goblet cells interspersed among colonocytes, contributing to the protective mucous layer.

The main function of Kolonzellen is the absorption of water and electrolytes from luminal contents, a key process in fecal formation and fluid balance. They also participate in metabolic interactions with the gut microbiota, notably utilizing short-chain fatty acids such as butyrate produced by bacterial fermentation; butyrate serves as a major energy source for colonocytes and supports barrier function and health of the mucosa. In addition, colonocytes can engage in immune signaling and respond to microbial stimuli to help maintain intestinal homeostasis.

Turnover of colonocytes occurs in a dynamic process within the crypt–surface axis, with complete renewal of the colon epithelium occurring over several days (roughly 3–5 days in humans). Clinically, dysfunction or injury to colonocytes is linked to conditions such as inflammatory bowel disease and colorectal neoplasia, underscoring their essential role in colon physiology.