Cerebral vasomotor responses after recombinant interleukin 2 infusion

Area of Science:

• Neuroscience
• Immunology
• Vascular Biology

Background:

• Interleukin-2 (IL-2) is a cytokine with significant roles in immune responses.
• Systemic administration of IL-2 can have widespread physiological effects.
• Cerebral microcirculation plays a critical role in brain function and is regulated by vasomotor responses.

Purpose of the Study:

• To investigate the impact of systemic human recombinant interleukin-2 (rIL-2) infusion on cerebral vasomotor responsiveness.
• To assess the effects of rIL-2 on endothelium-dependent vasodilation induced by acetylcholine (Ach).
• To evaluate the influence of rIL-2 on the vasoconstrictor response to hypocapnia in cerebral arterioles.

Main Methods:

• Anesthetized rats received systemic infusions of rIL-2 or sterile water (control) for 3 days.
• Cerebral pial arterioles were observed using cranial windows.
• Vasomotor responses to topical Ach and hyperventilation-induced hypocapnia were measured.
• Vessels were examined using transmission electron microscopy for morphological changes.

Main Results:

• rIL-2 infusion abolished Ach-induced endothelium-dependent vasodilation in pial arterioles.
• Animals treated with rIL-2 showed reduced vasoconstrictive response to hypocapnia.
• Control animals exhibited normal vasomotor responses to both Ach and hypocapnia.
• Ultrastructural analysis revealed occasional morphological alterations in endothelial and smooth muscle cells of rIL-2 treated rats, but not consistently.

Conclusions:

• Repeated systemic rIL-2 infusion significantly alters vasomotor responsiveness in the cerebral microcirculation.
• The observed functional changes in cerebral blood vessels may occur without overt morphological damage.
• These findings highlight potential neurovascular side effects of systemic IL-2 therapy.