The contact system in human malignant and benign ascites

Area of Science:

• Biochemistry
• Oncology
• Gastroenterology

Background:

• The plasma contact system, involving factors XII and XI and prekallikrein, plays a role in hemostasis and inflammation.
• Understanding its role in pathological conditions like cancer-associated ascites is crucial.

Purpose of the Study:

• To investigate the activation status of the plasma contact system in ascites and plasma of patients with gastrointestinal cancer and liver failure.
• To identify the components and inhibitors of the contact system present in these biological fluids.

Main Methods:

• Analysis of ascites and plasma samples from patients.
• Assays to detect factor XII, factor XI, prekallikrein, and their inhibitors.
• Measurement of factor XII-like and plasma kallikrein-like activities.
• Assessment of functional inhibition values.

Main Results:

• Factor XII, XI, and prekallikrein, along with their inhibitors, were present in ascites and plasma of both patient groups.
• Factor XII-like and plasma kallikrein-like activities were detected in malignant ascites, with kallikrein-like activity complexed to alpha 2-macroglobulin.
• Plasma levels of factor XII and prekallikrein were decreased, while functional inhibition values in ascites and plasma were unexpectedly high.
• Proenzyme levels were lower in benign ascites compared to malignant ascites.

Conclusions:

• The plasma contact system is activated in malignant ascites associated with gastrointestinal cancer.
• Activation of the contact system generates vasoactive mediators.
• These mediators may contribute to the pathogenesis and accumulation of malignant ascites.