Parenteral nutrition maintains pulmonary IgA antibody transport capacity, but not active transport, following injury

BackgroundParenteral nutrition (PN) increases post-trauma pneumonia versus enteral feeding. PN impairs murine immunoglobulin A (IgA) airway defenses and abrogates a normal IgA increase following injury. This work investigates the effect of type/route of nutrition on lung IgA and its transport protein, polymeric immunoglobulin receptor (pIgR), after injury.MethodsCatheterized mice were randomized to Chow or PN for 5 days and sacrificed without injury (Chow: n = 12; PN n = 11), or 8 hours after laparotomy + neck incisions (Chow-injury: n = 11, PN-injury: n = 13). Bronchoalveolar lavage (BAL) and lung IgA levels were analyzed by enzyme-linked immunosorbent assay (ELISA) and lung pIgR by Western blot.ResultsBAL IgA levels increased in Chow-injury versus PN-injury (P <.01) with no differences in pIgR. PN-injury tissue IgA levels decreased versus Chow (P <.01), Chow-injury (P <.01), and PN (P <.05).ConclusionsPN impairs the airway IgA response to injury but not due to impaired IgA transport capacity/pIgR level.