Lipid Compositions of Total Parenteral Nutrition Affect Gut Peyer's Patches and Morphology in Mice.

ABSTRACT

INTRODUCTION: Although parenteral nutrition (PN) is the only option for providing adequate nutrition to patients who cannot tolerate oral ingestion, it severely impairs intestinal barrier function in terms of morphology and immunity. While addition of either soybean oil (SO) or fish oil (FO) to PN partially reverses these defects, the effects of the oil composition (FO/SO ratio) on morphology and gut-associated lymphoid tissues (GALT) have yet to be elucidated. We focused on the effects of the FO/SO ratio in PN on the number of lymphocytes in Peyer's patches, immunoglobulin A levels, and intestinal structures. METHODS: Male ICR mice (n = 61) were randomized into five groups; oral nutrition (Chow, n = 14) and four groups receiving PN without oral nutrition. PN solutions contained fat emulsions with the following FOSO ratios 01 (SO, n = 12), 111.5 (11.5FSO, n = 17),12 (12FSO, n = 13) and 10 (FO, n = 5). All mice underwent jugular vein catheter insertion. The PN groups were given isocaloric and isonitrogenous nutritional support with 20% of total calories from fat emulsions with equivalent fat delivery in 11.9 g/kg/d. After 5 d of each feeding, Peyer's patches lymphocytes were isolated from the small intestine, counted and analyzed with flowcytometry for determination of their phenotypes (αßTCR+, γδTCR+, CD4+, CD8+ and B cells). Villus height and crypt depth of the jejunum and ileum were evaluated with hematoxylin-eosin staining. Immunoglobulin A levels in the intestinal washings were also determined. RESULTS: Numbers of total lymphocytes and B lymphocytes in PP were increased in the 12 FSO-PN but neither in the 111.5 FSO nor the FO group, as compared to the SO group. There were no marked differences among the groups in numbers neither of total T cells nor in any of T cell phenotypes determined. The 12 FSO group showed significantly greater villus height and crypt depth than the SO group. IgA levels did not differ significantly among the four PN groups. CONCLUSIONS: The PN with 12 FSO (FOSO = 12) maintained lymphocyte numbers in PP and intestinal villus morphology at levels nearly the same as those obtained with chow feeding. An appropriate ratio of FO to SO in PN is expected to prevent immunological impairment and morphological atrophy of the gut associated with lack of oral nutrition.