Atorvastatin reduces endotoxin-induced microvascular inflammation via NOSII

Area of Science:

• Pharmacology
• Cardiovascular Research
• Inflammation Biology

Background:

• Sepsis-induced endotoxaemia causes microvascular inflammation.
• Pravastatin previously reduced inflammation via nitric oxide synthase III (NOSIII).
• Atorvastatin's pleiotropic effects in endotoxaemia via similar mechanisms are unknown.

Purpose of the Study:

• To investigate if atorvastatin exerts beneficial anti-inflammatory effects in a lipopolysaccharide (LPS)-induced rat model of endotoxaemia.
• To determine if these effects are mediated by nitric oxide synthase (NOS) pathways, specifically NOSII and NOSIII.

Main Methods:

• Male Wistar rats were subjected to LPS infusion to induce endotoxaemia.
• Atorvastatin was administered pre-emptively.
• Mesenteric microcirculation was analyzed using intravital microscopy.
• Macromolecular leak and mean arterial blood pressure (MAP) were measured.
• NOSII and NOSIII expression was assessed via immunohistochemistry.

Main Results:

• LPS significantly decreased MAP and increased macromolecular leak, indicative of inflammation.
• Atorvastatin administration reversed the decrease in MAP and attenuated macromolecular leak.
• Atorvastatin reduced LPS-induced upregulation of endothelial NOSII but did not alter NOSIII expression.
• NOS inhibition studies confirmed the involvement of NOSII.

Conclusions:

• Atorvastatin demonstrates beneficial anti-inflammatory and hemodynamic effects in a rat model of endotoxaemia.
• These effects are associated with the downregulation of pro-inflammatory NOSII, distinct from pravastatin's mechanism.
• The findings highlight the importance of considering specific statin types for their pleiotropic effects in inflammatory conditions.