Interleukin-1 alpha as a factor in occlusive vascular disease

Area of Science:

• Cardiovascular Biology
• Immunology
• Pathology

Background:

• Interleukin-1 alpha (IL-1 alpha) is known to affect endothelial cells and promote cell replication.
• These effects suggest a potential role for IL-1 alpha in the myointimal proliferation seen in vascular sclerosis.

Purpose of the Study:

• To investigate the presence of IL-1 alpha in saphenous veins and internal mammary arteries before and after use as aortocoronary bypass grafts.
• To determine if IL-1 alpha correlates with histopathologic changes indicative of vascular sclerosis.

Main Methods:

• Immunohistochemical analysis using a peroxidase-immunoperoxidase method to detect IL-1 alpha.
• Examination of saphenous veins and internal mammary arteries before implantation and bypass grafts during revascularization.

Main Results:

• IL-1 alpha was detected in 13 phlebosclerotic saphenous veins before implantation but not in 30 unchanged veins.
• IL-1 alpha was absent in all 43 sampled internal mammary arteries.
• All 55 bypass grafts with histopathologic abnormalities, including myointimal proliferation, showed widespread IL-1 alpha.

Conclusions:

• The absence of IL-1 alpha in internal mammary arteries may explain their resistance to luminal narrowing and better clinical outcomes as bypass grafts.
• The presence of IL-1 alpha in diseased vessels suggests it is an indicator and potential participant in vascular injury and occlusion.