Role of surfactant proteins A and D in sepsis-induced acute kidney injury

Shock. 2015 Jan;43(1):31-8. doi: 10.1097/SHK.0000000000000270.

Abstract

Sepsis is a major cause of acute kidney injury (AKI) with high rates of morbidity and mortality. Surfactant proteins A and D (SP-A, SP-D) play a critical role in host defense and regulate inflammation during infection. Recent studies indicate SP-A and SP-D are expressed in the kidney. The current study examines the role of SP-A and SP-D in the pathogenesis of sepsis-induced AKI. Wild-type (WT) and SP-A/SP-D double-knockout (KO) C57BL/6 mice were treated by cecal ligation and puncture (CLP) or sham surgery. Histological, cellular, and molecular indices of kidney injury were investigated in septic mice 6 and 24 h after CLP. Twenty-four hours after CLP, kidney injury was more severe, renal function was decreased, and blood creatinine and blood urea nitrogen were higher in septic SP-A/SP-D KO mice (P < 0.05, versus septic WT mice). Kidney edema and vascular permeability were increased in septic SP-A/SP-D KO mice (P < 0.01, versus septic WT mice). Apoptotic cells increased significantly (P < 0.01) in the kidney of septic SP-A/SP-D KO mice compared with septic WT mice. Molecular analysis revealed levels of Bcl-2 (an inhibitor of apoptosis) were lower and levels of caspase 3 (a biomarker of apoptosis) were higher in the kidney of septic SP-A/SP-D KO mice (P < 0.01, versus septic WT mice). Furthermore, levels of nuclear factor κB and phosphorylated IκB-α increased significantly in the kidney of septic SP-A/SP-D KO mice compared with septic WT mice, suggesting SP-A/SP-D KO mice have a more pronounced inflammatory response to sepsis. We conclude SP-A and SP-D attenuate kidney injury by modulating inflammation and apoptosis in sepsis-induced AKI.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury / etiology
  • Acute Kidney Injury / genetics
  • Acute Kidney Injury / metabolism*
  • Acute Kidney Injury / pathology
  • Animals
  • Apoptosis / genetics
  • Capillary Permeability / genetics
  • Creatinine / blood
  • Disease Models, Animal
  • Mice, Knockout
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Pulmonary Surfactant-Associated Protein A / genetics
  • Pulmonary Surfactant-Associated Protein A / metabolism*
  • Pulmonary Surfactant-Associated Protein B / genetics
  • Pulmonary Surfactant-Associated Protein B / metabolism*
  • Sepsis / complications
  • Sepsis / genetics
  • Sepsis / metabolism*
  • Sepsis / pathology

Substances

  • NF-kappa B
  • Proto-Oncogene Proteins c-bcl-2
  • Pulmonary Surfactant-Associated Protein A
  • Pulmonary Surfactant-Associated Protein B
  • Bcl2 protein, mouse
  • Creatinine