Early ascorbic acid administration prevents vascular endothelial cell damage in septic mice

Area of Science:

• Biochemistry
• Pharmacology
• Critical Care Medicine

Background:

• Tetrahydrobiopterin (BH4) oxidation by nitric oxide synthase (NOS) uncoupling generates reactive oxygen species (ROS), contributing to vascular endothelial dysfunction.
• Ascorbic acid (AsA) is known to inhibit BH4 oxidation and mitigate ROS production.
• The optimal timing for AsA administration in sepsis to effectively manage BH4 kinetics and improve outcomes remains undetermined.

Purpose of the Study:

• To investigate the impact of early versus late AsA administration on vascular endothelial dysfunction and survival in a murine model of sepsis.
• To elucidate the effects of AsA timing on BH4 oxidation, endothelial damage markers, and organ injury during sepsis.

Main Methods:

• Sepsis was induced in mice using cecal ligation and puncture (CLP).
• Ascorbic acid (200 mg/kg) was administered either immediately after CLP (early group) or 12 hours post-CLP (late group).
• Survival rates, BH4 oxidation status (dihydrobiopterin/tetrahydrobiopterin ratio), serum syndecan-1 levels, and liver damage were assessed.

Main Results:

• Early AsA administration significantly improved survival rates compared to the non-treated group (p < 0.05).
• The late AsA administration group did not show improved survival compared to controls.
• Early AsA treatment led to reduced BH4 oxidation, lower syndecan-1 levels, and decreased organ damage in septic mice.

Conclusions:

• Immediate post-sepsis AsA administration is crucial for improving survival in a murine CLP model.
• Early AsA intervention protects vascular endothelial cells by inhibiting BH4 oxidation, thereby mitigating organ dysfunction and enhancing survival.
• The timing of AsA administration is a critical factor for its therapeutic efficacy in sepsis-induced vascular complications.