PSV-8 Early Life Adversity Impacts Intestinal Epithelial Development and Stem Cells Activities in Pigs
Authors: Yu Liang-en , Mann Peter , Schlitzkus Lydia , Chakradhar Jiniya , Li Yihang 
Published: October 2023

Abstract
Early life adversity significantly impacts organ development and predisposes animals towards greater risk of diseases later in life. In the previous research in pigs, long lasting intestinal barrier dysfunctions have been found to be associated with early weaning stress. However, the underlying mechanism is not fully elucidated. Intestinal epithelial functions are associated with the number and maturation of multicellular components, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells (EEC). Intestinal epithelial stem cells (IESC) give rise to the whole epithelium within 5 to 7 days. Such rapid turnover rate allows intestinal adaptation to stress conditions. We hypothesized that the early life stress impacted stem cells activities which would contribute to the long-lasting post-stress functional changes in intestinal epithelium. The objective of the present study is to evaluate the epithelium component cells and IESC proliferation and differentiation activities in an early weaning stress model in pigs. Piglets (n = 18) were obtained from commercial litters and were pair-weaned at the age of d 15 (early weaning, EW) and d 26 (late weaning, LW). Piglets were co-housed and raised under the same conditions. At the age of d 35, ileal tissues were isolated and fixed for morphological measurements. Intestinal crypts were isolated and cultured in the Matrigel matrix to form enteroids. The proliferation activities of IESCs were measured by enteroids morphology; differentiation capacity was measured by quantification of epithelial cell markers with and without chemicals-induced enteroids differentiation. Gene expressions and (or) staining of specific markers for IESCs (Olfm4, BMI1), enterocytes (ALP1), goblet cells (Muc2), Paneth cells (LYZ), and EECs (ChgA) in ileal tissue and ileal enteroids were also quantified. Data were analyzed by the student’s t-test. Our results showed that EW significantly (P &lt; 0.05) reduced ileal villus width and crypt fission rate, while no changes were found on villus height and crypt depth compared with LW control. The alterations of ileal epithelium components in EW pigs were indicated by significantly fewer number of EECs, greater number of the goblet cells, and reduced ALP1 marker expression. The enteroids formation and budding rates were both significantly suppressed in EW pigs, which indicated a reduced IESC proliferating activity. In the fully developed enteroids, gene expressions of LYZ, ALP1, BMI1, Olfm4, and Hes1 were least in EW, but Muc2 expression was greater compared with control. In the differentiation culture media, the enteroids from EW pigs exhibited significantly enhanced potential for goblet cell differentiation but reduced capacity for enterocyte differentiation compared with LW pigs. Overall, the results indicate that early weaning stress affects the programming and activity of IESCs, which leads to an altered epithelium cell population and intestinal functions. Further understanding of mechanisms regulating IESCs activity will shed light on novel strategies mitigating stress-associated intestinal dysfunctions.