The increase during sepsis in the plasma levels of inflammatory cytokines may result in renal proximal tubular cell (PTC) injury, thereby contributing to acute renal injury (AKI) and mortality. Our preliminary results suggest that an increase in intracellular prostaglandin E2 (iPGE2) -triggered by inflammatory cytokines and dependent on the prostaglandin uptake transporter PGT- plays a relevant role in PTC injury. Therefore, PGT inhibitors such as Bromosulfophthalein would protect PTC against the noxious effects of inflammatory cytokines during sepsis.
The present project is aimed to confirm that: Bromosulfophthalein prevents PTC injury sepsis-induced PTC injury (new in vitro model of PTC injury by inflammatory cytokynes and bacterial lipopolysaccharide-LPS) as well as in vivo (LPS murine model of sepsis) and plasmas from septic patients induce PTC injury and that iPGE2 play a relevant role in PTC injury.
The results obtained to date have shown that:
1. Our in vitro model replicates key aspects of AKI, such as cell death, detachment, cytoskeletal disruption, and increased paracellular permeability. These alterations, which impair critically relevant tubular functions are driven by a PGT/iPGE2-dependent mechanism and prevented by Bromosulfophthalein.
2. Our in vitro model also replicates the pro-inflammatory activation of PTC cells during sepsis through i) increasing leukocyte infiltration via upregulation of ICAM-1, VCAM-1, and MCP-1 and ii) secreting factors that induce monocyte chemotaxis, adhesion, and activation into macrophages. Again, these processes rely on a PGT/iPGE2-dependent mechanism and prevented by Bromosulfophthalein.
3. Plasma from patients with sepsis-induced AKI contains soluble factors that, through a PGT/iPGE2-dependent, Bromosulfophthalein-sensible mechanism, cause cell death, reduced proliferation, increased permeability, and pro-inflammatory activation in HK-2 cells.
Based on these results, which confirm the hypothesis and the objectives outlined above, it remains to be confirmed that Bromosulfophthalein also prevents sepsis-induced AKI in an in vivo model.
