Serum concentrations of extracellular matrix components: novel markers of metabolic control and hepatic pathology in glycogen storage disease?

Laminin, hyaluronic acid (HA), procollagen III amino-terminal propeptide (PIIINP), and procollagen I carboxy-terminal propeptide (PICP) concentrations were measured by radioimmunoassay or radiometric assay in sera from 21 patients with glycogen storage disease (GSD). Laminin was increased in 16 of 29 samples from the six children with GSD I, 25/43 from the seven with GSD III, and 3/19 from the eight with GSD IX; laminin correlated with serum aspartate aminotransferase and gamma-glutamyltransferase but not with serum triglycerides, cholesterol, lactate, or urate. HA was increased in 20% of samples from GSD I, 58% from GSD III, and in none from GSD IX; HA correlated with serum lactate and urate but not with liver function tests, serum cholesterol, or triglycerides. Serum PIIINP was increased in only eight samples and PICP in only one; children with poor linear growth had low PIIINP and PICP. Immunostaining studies of nine liver biopsies taken at diagnosis showed increased laminin and PIIINP staining in portal tracts, fibrous septa, and around sinusoids in periportal regions; children with a greater degree of immunostaining did not always show significantly higher values of serum laminin or PIIINP. We speculate that raised serum laminin may reflect fibrogenesis (but not necessarily established fibrosis) in response to tissue damage in GSD, raised HA may reflect disturbed sinusoidal endothelial cell function, and low PIIINP and PICP impaired somatic growth rather than intrahepatic pathology.