Increased levels of tPA antigen and tPA/PAI-1 complex in myotonic dystrophy

To assess the fibrinolytic system in myotonic dystrophy (DM1), a disease connected to features of the metabolic syndrome, including a prominent insulin resistance, increased body fat mass, and hypertriglyceridaemia. We hypothesized that abnormalities in the fibrinolytic system are linked to metabolic dysfunction in DM1.

Circulating morning levels of tissue plasminogen activator (tPA) and plasminogen activator inhibitor type 1 (PAI-1) antigens, tPA/PAI-1 complex, lipids and insulin were determined. Genetic analyses, including calculation of allele size, were performed in all patients. Body fat mass was estimated with bioelectrical impedance analysis.

Out-patient clinic in collaboration with Umeå University Hospital.

A total of 42 otherwise healthy patients with DM1 (22 men, 20 women; median age 41.5 years) and 50 controls (27 men, 23 women; median age 42.0 years).

The tPA and PAI-1 antigens, tPA/PAI-1 complex, blood lipids and body fat mass.

The tPA antigen and tPA/PAI-1 complex levels were significantly increased in DM1 patients (P < 0.001 and P < 0.05, respectively) whilst levels of PAI-1 did not differ from controls. Triglyceride levels were increased (P < 0.001) whereas HDL cholesterol levels were lower in DM1 patients (P < 0.05). Body fat mass was increased in DM1 patients (P < 0.001).

The fibrinolytic system is disturbed in DM1 patients, with increased levels of tPA and tPA/PAI-1 complex but paradoxically unaltered levels of PAI-1, in spite of a severely increased body fat mass. This may imply an abnormal function of adipose tissue in DM1, and calls for further studies of the fibrinolytic system in this disease.bstra