Influence of adding fish oil to parenteral nutrition on gut-associated lymphoid tissue.
BACKGROUND
Lack of enteral nutrition reduces gut-associated lymphoid tissue (GALT) mass and function, a mechanism underlying the increased morbidity of infectious complications in severely injured or critically ill patients. Strategies to restore parenteral nutrition (PN)-induced changes of GALT mass and function have been pursued. However, the influences of adding fish oil to PN on gut immunity remain to be clarified.


METHODS
Male Institute of Cancer Research (ICR) mice (n = 50) were randomized to 4 groups: ad libitum chow (chow), fat free PN (fat (-)-PN), PN + fish oil (FO-PN), and PN + safflower oil (SO-PN). The PN groups were given isocaloric and isonitrogenous PN solutions. The FO- and SO-PN groups received 20% of total calories from fat emulsions. After 5 days of feeding, lymphocytes from Peyer's patches (PPs), the intraepithelial space (IE), and the lamina propria (LP) of the entire small intestine were isolated. GALT lymphocyte numbers and phenotypes (CD4+, CD8+, alphabetaTCR+, gammadeltaTCR+, B220+ cells) were determined. Immunoglobulin A (IgA) levels of small intestinal washings were also measured by enzyme-linked immunosorbent assay. Another set of mice (n = 24) was used to determine plasma fatty acid compositions after feeding.


RESULTS
Lymphocyte numbers from PPs and the LP and intestinal IgA levels were significantly lower in the PN groups than in the chow group, with no significant differences between any 2 PN groups. The FO- and SO-PN groups showed moderate recovery of IE cell numbers compared with the fat (-)-PN group. Omega-3 and omega-6 fatty acid levels were increased with fish and safflower oil additions, respectively, compared with the fat (-)-PN group.


CONCLUSIONS
Adding fish oil to PN does not exacerbate PN-induced GALT changes but rather partially reverses these changes, with increased plasma omega-3 fatty acid levels.
Maeshima
Yoshinori
Y
Department of Surgery, National Defense Medical College, Saitama, Japan.
Fukatsu
Kazuhiko
K
Moriya
Tomoyuki
T
Ikezawa
Fumie
F
Ueno
Chikara
C
Saitoh
Daizoh
D
Mochizuki
Hidetaka
H
D000818:Animals; D016638:Critical Illness; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000378:metabolism; D005395:Fish Oils / Q000494:pharmacology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis / Q000276:immunology; D007413:Intestinal Mucosa / Q000187:drug effects / Q000276:immunology; D007421:Intestine, Small / Q000187:drug effects / Q000276:immunology*; D018655:Lymphocyte Count; D008221:Lymphoid Tissue / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009929:Organ Size; D010288:Parenteral Nutrition / Q000379:methods*; D010581:Peyer's Patches / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D011897:Random Allocation; D012450:Safflower Oil / Q000494:pharmacology
D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D007070:Immunoglobulin A; D012450:Safflower Oil