Prostaglandin-secreting cells: a portable first aid kit for tissue repair

Abstract

Nonstandard abbreviations used: DSS, dextran sodium sulfate; PSC, prostaglandin-expressing stromal cell; Ptgs2, prostaglandin-endoperoxide synthase 2.

Perinatal lipid nutrition alters early intestinal development and programs the response to experimental colitis in young adult rats

“…Whether impaired epithelial barrier integrity contributed to increased sensitivity to DNBS-induced colitis, however, is speculative. Among several cytokines, increased TNF-␣ synthesis impairs epithelial barrier structure and function but also increases PGE 2 synthesis (35,39). In the present study, TNF-␣ concentrations were higher in the 3-mo-old colitic rats in the FO than SO or CO groups.…”

“…The colon consists of tubular crypts lined with a single layer of epithelial cells that provide a regulated barrier for nutrient, ion, and water absorption and prevent luminal pathogen access (39). Multipotent precursor crypt stem cells produce new, proliferating progenitor cells that differentiate into lineagespecific cells to replace damaged and aging cells, with the proliferative rate regulated to meet the needs for cell renewal under basal conditions and when needs are increased by injury and cell loss (12,39).…”

“…Multipotent precursor crypt stem cells produce new, proliferating progenitor cells that differentiate into lineagespecific cells to replace damaged and aging cells, with the proliferative rate regulated to meet the needs for cell renewal under basal conditions and when needs are increased by injury and cell loss (12,39). Differences in cholesterol-to-phospholipid ratio and phospholipid fatty acids occur with colonocyte differentiation and are believed to be important to functional maturation (1,6).…”

“…In the present study, TNF-␣ concentrations were higher in the 3-mo-old colitic rats in the FO than SO or CO groups. PGE 2 , however, plays complex roles in intestinal responses to injury, and, although PGE 2 is often considered proinflammatory (41), PGE 2 synthesized by inducible COX-2 also functions to negatively regulate the inflammatory response (25,26,33,39). During inflammation, mucosal PGE 2 synthesis is increased and correlates with disease activity in human IBD and experimental colitis.…”

“…Continual renewal of damaged and aging epithelial cells through crypt cell proliferation, with a cell lifetime of 2-5 days (12), places a high demand on the intestine for nutrients required for cell proliferation and membrane synthesis, including the n-6 and n-3 fatty acids. Not only are n-6 and n-3 fatty acids important membrane components, they are also precursors of potent lipid mediators termed eicosanoids that modulate epithelial barrier maturation and the initiation, propagation, and termination of inflammation and barrier recovery postinjury (15,25,26,31,39,41,42). The eicosanoid metabolite PGE 2 (a series 2 eicosanoid) synthesized via cyclooxygenase (COX)-1 and COX-2 from arachidonic acid (20:4n-6) not only is important in inflammation but also plays central roles in intestinal crypt cell survival and proliferation, intestinal permeability, and response to injury (2,15,31,33).…”