The Haptoglobin Response after Aneurysmal Subarachnoid Haemorrhage

Area of Science:

• Neuroscience
• Biochemistry
• Immunology

Background:

• Haptoglobin protects against extracellular hemoglobin toxicity after subarachnoid hemorrhage (SAH).
• Investigating haptoglobin's role in CSF and serum following SAH is crucial for understanding its protective mechanisms and therapeutic potential.

Purpose of the Study:

• To investigate the haptoglobin response in cerebrospinal fluid (CSF) and serum after subarachnoid hemorrhage (SAH).
• To determine the association between haptoglobin levels and clinical outcomes post-SAH.
• To explore the potential for therapeutic haptoglobin supplementation.

Main Methods:

• Paired CSF and serum samples from 19 controls and 92 SAH patients were analyzed.
• Techniques included ultra-performance liquid chromatography, immunoassay, and colorimetry.
• CSF/serum albumin and haptoglobin quotients were used to compute the CSF haptoglobin index.

Main Results:

• Marked CSF haptoglobin deficiency was observed in SAH patients, with 99% of extracellular hemoglobin unbound.
• SAH patients showed a significantly lower CSF haptoglobin index compared to controls, particularly Haptoglobin-1 allele carriers.
• Serum haptoglobin levels increased post-SAH and correlated with CSF cytokine levels, but haptoglobin variables did not associate with long-term outcomes.

Conclusions:

• Intrathecal haptoglobin consumption occurs after SAH, especially in Haptoglobin-1 carriers.
• Serum haptoglobin is upregulated post-SAH, indicating an acute phase response to central inflammation.
• Low CSF haptoglobin levels suggest therapeutic supplementation may be beneficial, as variations do not impact long-term outcomes.