An in vitro model for abnormal skeletal development in the lysosomal storage diseases

Abstract

Lysosomal storage diseases such as GM1-gangliosidosis are associated with skeletal abnormalities. Radiological and histological studies, both in human and corresponding animal models, indicate retarded bone formation. Since cartilage maturation leads to bone formation, we developed an in vitro system to study and compare the biological features of cartilage from dogs affected with GM1-gangliosidosis with age-matched controls. Costochondral chondrocytes were grown in monolayer and in agarose culture. Both affected and control cells dedifferentiated in monolayer; however, in agarose culture they re-expressed the chondrocytic phenotype. Cells from affected dogs were enlarged and contained numerous large vacuoles when compared with control cells. This morphology was similar to that seen in vivo. In addition, the affected cells appeared to have a reduction in mitosis and alcian blue staining proteoglycans. Cultures from affected animals contained fewer cells positive for alkaline phosphatase activity. Both affected and control cells expressed collagen types I and II and were positive for the lectin Ricinus communis agglutinin-I. However, the staining of the control culture for type II collagen was more prominent than in the affected cells. These findings suggest that culture of chondrocytes in agarose may be a useful method for studying the biology of cartilage which leads to skeletal abnormalities in lysosomal storage diseases.

Case series of two siblings suffering from GM1 gangliosidosis resulting in early multiple joint arthroplasties

“…There have been reports of progressive skeletal dysplasia and skeletal lesions characterised by retarded endochondral ossification in vertebral epiphyses leading to premature avascular necrosis of joints [8][9][10]. Gaucher disease, the most common of the lysosomal storage diseases, has many hallmarks of chronic inflammation related to microvascular occlusion including avascular necrosis [6,7].…”

Extracellular matrix components: An intricate network of possible biomarkers for lysosomal storage disorders?

“…In the same disorder, a PG‐rich ECM in gingival tissue of a patient was found [112]. Finally, concerning LSDs with prominent skeletal involvement, an alteration in PG expression was found in the cartilage of mucolipidosis and I‐cell disease patients [107,121], while a reduction in PG expression was characteristic in chondrocytes obtained from a GM 1 gangliosidosis canine animal model [106].…”

“…Another illustrative example of the connection between fibrous elements’ alterations and the symptomatology of a specific disease is that of GM 1 gangliosidosis. In an effort to create an in vitro model to study cartilage maturation in this group of patients, Aulthouse and Alroy have demonstrated a decrease in collagen type II expression in deficient canine chondrocytes, as opposed to normal cells [106]. This dysregulation in matrix production could represent a possible theory for the explanation of skeletal abnormalities, not only in GM 1 gangliosidosis but in other LSDs, as well, such as in I‐cell disease where a decrease in collagen fibril diameter was noticed in cultured chondrocytes [107].…”