Plasma plasmin inhibitors in duchenne-type progressive muscular dystrophy

In our previous research, we found that the level of the plasminogen activity in the plasma from Duchenne-type patients with progressive muscular dystrophy was higher than of the normal boys, though the level of the plasmin inhibitors was lower. Therefore, in the present study, we investigated the differences in the fractions of plasmin inhibitors.

The subjects were nine patients (the average age being 17.1 years) who had been diagnosed, by clinical and biochemical tests, as having PMD; serving as controls were normal boys (the average age being 15 years), the patients' mothers, and the mothers of the normal boys.

The plasmin inhibitors were separated from plasma using lysine-Sepharose columns according to the method of Urita et al. (6). The determination was performed based on the method of Aoyagi et al. (7) and an immunoreactive assay.

The results were as follows: (1) No significant differences were seen between patients with PMD and control subjects with respect to either α₁-antichymotrypsin, antithrombin III, and α₁-antitrypsin or α₂-macroglobulin and inter-α-trypsin inhibitors. These results suggested that the low level of plasmin inhibitors in patients was due to the low activity of the C₁ inactivator. (2) The patients with PMD showed lower values than the normal boys in the levels of C₁ inactivator in plasma; similarly, the mothers of these patients showed lower values than the normal mothers.