Patients with
acute kidney injury (AKI) have increased serum proinflammatory
cytokines and an increased occurrence of respiratory complications. The aim of the present study was to examine the effect of renal and extrarenal
cytokine production on AKI-mediated
lung injury in mice. C57Bl/6 mice underwent
sham surgery,
splenectomy, ischemic AKI, or ischemic AKI with
splenectomy and kidney, spleen, and liver
cytokine mRNA, serum
cytokines, and
lung injury were examined. The proinflammatory
cytokines IL-6, CXCL1, IL-1β, and TNF-α were increased in the kidney, spleen, and liver within 6 h of ischemic AKI. Since splenic proinflammatory
cytokines were increased, we hypothesized that
splenectomy would protect against AKI-mediated
lung injury. On the contrary,
splenectomy with AKI resulted in increased serum
IL-6 and worse
lung injury as judged by increased lung capillary leak, higher lung
myeloperoxidase activity, and higher lung CXCL1 vs. AKI alone.
Splenectomy itself was not associated with increased serum
IL-6 or
lung injury vs.
sham. To investigate the mechanism of the increased proinflammatory response, splenic production of the anti-inflammatory
cytokine IL-10 was determined and was markedly upregulated. To confirm that splenic
IL-10 downregulates the proinflammatory response of AKI,
IL-10 was administered to splenectomized mice with AKI, which reduced serum
IL-6 and improved
lung injury. Our data demonstrate that AKI in the absence of a counter anti-inflammatory response by splenic
IL-10 production results in an exuberant proinflammatory response and
lung injury.