Experimental aortitis. Aortic lesions induced by a serine protease

Area of Science:

• Vascular Biology
• Immunology
• Pathology

Background:

• The exact cause of aortitis syndrome, also known as Takayasu's arteritis, remains unknown.
• Understanding the etiology of this condition is crucial for developing effective treatments.

Purpose of the Study:

• To investigate whether aortic and pulmonary artery lesions can be experimentally induced by a low dose of circulating protease.
• To explore the potential role of serine proteases in the pathogenesis of aortitis.

Main Methods:

• Rabbits received intravenous infusions of trypsin or chymotrypsin-A4.
• Serum enzyme activity was monitored.
• Aortic and pulmonary artery tissues were examined histopathologically at 2 and 6 weeks post-infusion.

Main Results:

• Trypsin infusion significantly increased serum trypsin activity and induced aortic wall thickening, edema, and intimal/medial tears.
• Similar lesions were observed in rabbits treated with chymotrypsin-A4.
• Lesions were most prominent in the ascending aorta and pulmonary artery, with minimal inflammation in controls.

Conclusions:

• A small dose of serine protease in circulating blood can induce diffuse lesions in the aorta and pulmonary artery.
• These findings suggest a potential mechanism for protease-induced vascular damage relevant to aortitis.