The source of plasminogen activator in human saliva

Area of Science:

• Biochemistry
• Oral Biology
• Physiology

Background:

• Human saliva possesses various biological activities.
• Fibrinolysis is a crucial physiological process involving the breakdown of blood clots.
• Previous studies have investigated salivary enzymes, but the source of fibrinolytic activity in mixed saliva remained unclear.

Purpose of the Study:

• To investigate the source of fibrinolytic activity in human mixed stimulated saliva (MSS).
• To determine if fibrinolytic activity is associated with specific salivary components or cell types.

Main Methods:

• Collected human mixed stimulated saliva (MSS).
• Separated saliva into supernatant and pellet fractions.
• Assessed fibrinolytic (plasminogen activator) activity in both fractions and resuspended pellets.
• Examined the association of activity with epithelial cells and cell fragments.

Main Results:

• Fibrinolytic activity was detected in human mixed stimulated saliva (MSS).
• No significant fibrinolytic activity was found in the supernatants of MSS, parotid, or submandibular salivas.
• Fibrinolytic activity was primarily associated with the resuspended pellets, specifically with epithelial cells and cell fragments.

Conclusions:

• The fibrinolytic activity present in human mixed stimulated saliva (MSS) originates from its epithelial cell component.
• This finding clarifies the source of plasminogen activator activity in saliva.
• Salivary epithelial cells play a role in local fibrinolysis.