Increased lung surfactant phosphatidylcholine in patients affected by lysosomal storage diseases

Sandhoff disease, Gaucher disease type I and sialidosis type I are lysosomal storage disorders caused, respectively, by deficiency of activity of β-hexosaminidase (storage of GM₂ and GA₂ ganglioside), glucosylceramidase (storage of glucosylceramide) and α-neuraminidase (storage of glucopeptides and/or oligosaccharides). Progressive clinical systemic and neurological dysfunctions are observed. In these pathologies, respiratory infections often lead to death. Elevation of the lung surfactant phosphatidylcholine (PC) has previously been reported in the Hexb mouse, a model of Sandhoff disease. We evaluated phospholipids in the lung surfactant of patients affected by the described lysosomal diseases, observing a statistically significant increase of total lipid phosphate in the patients as compared with controls. Moreover, higher levels of PC in patients affected by sialidosis (3.6-fold) and Gaucher (4-fold) disease, and of PC (4.15-fold) and phosphatidylethanolamine (2.3-fold) in a patient affected by Sandhoff disease were noted. The latter confirms the previous results in the Hexb mouse. We suggest that changes in phospholipid metabolism can be common in different lysosomal storage disorders and can increase the susceptibility to respiratory infections, usually present in these disorders.