Route and Type of Nutrition Influence Mucosal Immunity to Bacterial Pneumonia

Abstract

ObjectiveTo develop a model of established respiratory immunity against Pseudomonas aeruginosa pneumonia and to investigate the effects of route and type of nutrition on this immunity. Summary Background DataDiet influences the ability of gut-associated lymphoid tissue (GALT) to maintain mucosal immunity. Complex enteral diets and chow maintain normal GALT populations against established IgA-mediated antiviral respiratory immunity. Both intravenous and intragastric total parenteral nutrition (TPN) produce GALT atrophy, but only intragastric TPN preserves established antiviral immunity. The authors hypothesized that both GALT-depleting diets (intragastric and intravenous TPN) would impair immunity against bacterial pneumonia. Methods P. aeruginosa was administered intratracheally to determine the mortality rate at increasing doses, and liposomes containing P. aeruginosa antigens were used to generate effective respiratory immunization. In the final experiment, mice received liposomes containing P. aeruginosa antigens to establish immunity and then were randomized to chow, complex enteral diets, intragastric TPN, or intravenous TPN. After 5 days of diet, mice received live intratracheal P. aeruginosa, and the death rate was recorded at 24 and 48 hours. ResultsThe LD50 and LD10, were 9 x 107 and 12 x 107, respectively. Immunization reduced the mortality rate from 66% to 12%. This immunization was maintained in mice fed chow or a complex enteral diet and was lost in animals receiving intravenous TPN. Intragastric TPN partially preserved this respiratory immunity. ConclusionsProtection against bacterial pneumonia can be induced by prior antigenic immunization. This protection is lost with intravenous TPN, partially preserved with a chemically defined enteral diet, and completely preserved with chow or complex enteral diets. Both route and type of nutrition influence antibacterial respiratory tract immunity.Nosocomial pneumonia occurs in 10% to 25% of mechanically ventilated patients, accounting for 15% of hospital-acquired infections.' Mortality rates attributable to these pneumonias range from 7% to 30% but can reach 40% to 50% when Pseudomonas or Acinetobacter is the causative organism.2'3 Route and type of nutrition affect the risk of pneumonia in seriously injured patients. Severely injured trauma patients receiving enteral nutrition have significantly fewer pneumonias compared with patients fed parenterally, implying an impairment in mucosal defenses in patients fed Supported by NIH grant 1 ROI GM053439.

Parenteral Nutrition Induces Organ Specific Alterations in Polymeric Immunoglobulin Receptor Levels

“…In studies of severely injured trauma patients, individuals randomized to enteral feeding sustained significantly fewer pneumonias and intraabdominal abscesses than an injured group fed parenterally [15,[20][21][22]. Experimentally, our work and that of others show that route and type of nutrition influence established mucosal immunologic defenses [13,16], intraperitoneal cytokine and immunologic responses [18], and systemic inflammatory responses to injury [6][7][8]. This work focuses on PN induced alterations in mucosal immunity.…”

“…We documented that PN decreases the number of T & B cells in the intestine [17] and lung (unpublished data), reduces the number antibody-forming cells in the upper respiratory tract (reduced production) in response to an acute infection [11], reduces levels of Th2-type IgA stimulating cytokines (reduced production), such as IL-4 and IL-10 [31], and reduces levels of pIgR protein within the intestinal mucosa (reduced transport) [26]. The overall effect of these alterations reduce available IgA production (reduced T & B cells and Th2-type cytokines) and transport (lowered intestinal pIgR levels) to impair or eliminate established anti-viral and antibacterial defenses in our murine model [13,16]. In one previous experiment, however, we documented that respiratory protection against the A/PR8 (H1N1) influenza virus was preserved in PN-fed mice when influenza-specific monoclonal polymeric IgA was provided exogenously [25].…”

A comparison of the effectiveness of the early enteral and natural nutrition after pancreatoduodenectomy

“…Enteral nutrition influences the ability of gut-associated lymphoid tissue to maintain mucosal immunity. Both route and type of nutrition influence antibacterial respiratory tract immunity (13). The integrity of both the immunologic and nonimmunologic barriers may be affected by any number of pathologic insults as well as by nutritional influences (14).…”

Impairment of Mucosal Immunity by Total Parenteral Nutrition: Requirement for IgA in Murine Nasotracheal Anti-Influenza Immunity

“…GALT atrophy occurs with associated decreases in PP cells, LP lymphocytes, and IE lymphocytes (IEL) (12); total SIgA levels decrease in the GI (12) and respiratory (14) tracts; and functional mucosal immunity is impaired in both the URT (14,15,18) and LRT (16,19). Anti-influenza mucosal immunity is maintained in the URT of mice fed TPN solution i.g.…”

“…Impaired mucosal immunity is observed in both the upper (URT) and lower (LRT) respiratory tracts of i.v. TPN-fed mice (12,15,16), and alterations in GI IL-4 and IL-10 levels have been reported (17). The impairment in immunity is reversed either by 3 days of oral alimentation (14) or by injection of i.v.…”