Fibrinolytic and Protease Inhibitory Systems in Spinal Cord Injured Patients with End-Stage Renal Disease

ABSTRACT

Earlier studies have revealed a variety of coagulation abnormalities in patients with long-standing spinal cord injury (SCI) and end-stage renal disease (ESRD). The present study was undertaken to examine the fibrinolytic and protease inhibitory systems in this population. Twelve spinal cord injured men with ESRD were studied. All patients had chronic active urinary tract infections, pressure ulcers and were practically bed-bound. The results were compared with those obtained in a group of 32 normal volunteers. Plasma plasminogen and unstimulated tissue-type plasminogen activator(t-PA) concentrations in the SCI-ESRD group were comparable with those found in the control group. No significant difference was found in plasma plasminogen activator inhibitor (PAI) activity in the two groups. In contrast, plasma α2-antiplasmin antigen concentration and antiplasmin activity were significantly reduced in the study population. In addition, plasma α1-antitrypsin activity and antigen concentration were significantly increased while the α2-macroglobulin activity-to-antigen concentration ratio was significantly reduced in the SCI-ESRD group.

Although the mechanism of the observed reduction in α2-antiplasmin and total antiplasmin activity is uncertain, its presence could enhance fibrinolysis in this otherwise thrombosis-prone population. Likewise, elevated α1-antitrypsin could attenuate tissue damage by leukocyte-derived proteases in the face of persistent suppurative infections. The reduced α2-macroglobulin activity-to-antigen concentration ratio was thought to reflect the presence of α2-macroglobulin complexes with various proteases generated by the activation of leukocytes, coagulation, fibrinolytic and other proteolytic systems.