Human ureter, a source of tissue plasminogen activator

Area of Science:

• Biochemistry
• Cell Biology
• Urology

Background:

• Plasminogen activators (PAs) are crucial for fibrinolysis.
• Different tissues exhibit varying profiles of PA expression, primarily urokinase (UK) or tissue-type PA (t-PA).
• Understanding PA release from specific human tissues is important for potential therapeutic applications.

Purpose of the Study:

• To investigate the types and quantities of plasminogen activators released by human ureter organ cultures.
• To characterize the enzymatic properties of the released PAs.
• To evaluate the potential of human ureter cells as a source for PA production.

Main Methods:

• Organ cultures of human ureters were established.
• Plasminogen activators released into the medium were analyzed using radioimmunoassay and affinity chromatography.
• Antibodies against UK and t-PA were used to differentiate between the two PA types.
• Fibrin-dependent activity was assessed.

Main Results:

• Human ureter organ cultures released significant amounts of plasminogen activators into the medium.
• Radioimmunoassay demonstrated that the predominant PA released was tissue-type plasminogen activator (t-PA), unlike most other tissue cultures that mainly release urokinase (UK).
• Affinity chromatography separated two distinct PA activities: a minor UK fraction and a major t-PA fraction, with the latter requiring fibrin for activation.

Conclusions:

• Human ureter organ cultures are a rich source of tissue-type plasminogen activator (t-PA).
• The identified t-PA activity exhibits fibrin-dependent properties.
• Cells derived from human ureters represent a promising and potentially valuable source for the production of t-PA.