Acute lung injury (ALI) and its more severe form acute respiratory distress syndrome (ARDS) are a leading cause of morbidity and mortality in critically ill patients. Despite decades of research, there is still no effective therapy for ALI/ARDS, and treatment options are largely limited to supportive care. Neutrophil-mediated inflammation and endothelial cell (EC) injury are unifying features of the pathogenesis of ALI/ARDS. Interleukin-8 (IL8) receptors IL8RA and IL8RB (ILRA/RB) on neutrophil membranes bind to IL8 with high affinity and play a critical role in neutrophil recruitment to sites of injury and/or inflammation. This study tested the hypothesis that administration of rat induced pluripotent stem (iPS) cell-derived ECs (iPS-ECs) overexpressing IL8RA/RB inhibits liposaccharide (LPS)-induced ALI.Design and Method:
12-wk-old ovariectomized SD rats were divided into three groups and received intra-peritoneal (i.p.) injection of saline (Sham); LPS (Escherichia coli 026:B6, Sigma-Aldrich, 10 mg/kg, i.p.) followed by i.v. infusion of saline; iPS-ECs overexpressing IL8RA/RB (IL8RA/RB-iPS-EC, 1.5 x 106 cells/rat, 2 hrs post LPS), or iPS-ECs overexpressing Ad-Null vector (AdNull-iPS-EC, 1.5 x 106 cells/rat, 2hrs post LPS), respectively. 6 hrs after LPS treatment, pro-inflammatory cytokine/chemokine mRNA levels were measured by real-time, RT-PCR in total lung homogenates. Neutrophil infiltration was assessed by immunohistochemical staining. Pulmonary edema was assessed by wet to dry weight ratio and Evans blue staining.Results:
Expression of mRNA for adhesion molecule [P-selectin, vascular cell adhesion molecule (VCAM)-1, and intercellular adhesion molecule (ICAM)-1], chemoattractant [cytokine-induced neutrophil chemoattractant (CINC)-2β and monocyte chemoattractant protein (MCP)-1], and pro-inflammatory cytokine [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] was markedly increased in lungs of LPS rats. Transfusion of IL8RA/RB-iPS-ECs significantly attenuated expression of the pro-inflammatory mediators (by 40–50%) in LPS-injured lungs. Transfusion of IL8RA/RB-ECs also significantly attenuated LPS-induced neutrophil infiltration, pulmonary edema and vascular permeability changes.Conclusions:
These provocative findings indicate that targeted delivery of iPS-ECs overexpressing IL8RA/RB protects against LPS-induced acute lung injury.