Elevated VIP and endotoxin plasma levels in human gram-negative septic shock

Area of Science:

• Microbiology
• Neuroendocrinology
• Critical Care Medicine

Background:

• Meningococcal disease can lead to severe septic shock.
• Endotoxins (lipopolysaccharides, LPS) are key components of Gram-negative bacteria implicated in sepsis.
• Vasoactive intestinal polypeptide (VIP) is a neuropeptide with known roles in physiological regulation.

Purpose of the Study:

• To investigate the relationship between plasma levels of vasoactive intestinal polypeptide (VIP) and endotoxin (lipopolysaccharides, LPS) in patients with meningococcal disease.
• To determine if these markers correlate with disease severity and circulatory status.
• To observe the effect of treatment on VIP levels.

Main Methods:

• Plasma samples were collected from 11 patients with bacteriologically verified meningococcal disease.
• Vasoactive intestinal polypeptide (VIP) and endotoxin (lipopolysaccharides, LPS) levels were measured.
• Patients were categorized based on clinical presentation (fulminant septicaemia with septic shock vs. meningitis/meningococcaemia).
• Sequential samples were analyzed from 3 patients during treatment.

Main Results:

• Patients with severe septic shock (n=5) had significantly higher initial levels of VIP (>4 pM) and endotoxin (>200 ng/liter) compared to those with meningitis/meningococcaemia (n=6) (VIP ≤2.5 pM, endotoxin ≤25 ng/liter; P < 0.001).
• A strong positive correlation was found between plasma endotoxin and VIP levels (r = 0.735, P = 0.01).
• VIP levels decreased rapidly in 3 patients following antibiotic and fluid treatment.

Conclusions:

• Elevated plasma endotoxin and VIP levels are associated with severe septic shock in meningococcal disease.
• Endotoxin appears to stimulate the VIP-ergic nervous system during the initial phase of Gram-negative septic shock.
• VIP levels may serve as a biomarker for disease severity and response to treatment in meningococcal sepsis.