What is "phospholipidosis"

n. (context pathology English) The abnormal deposition of phospholipids, especially in the alveoli

Phospholipidosis is a lysosomal storage disorder characterized by the excess accumulation of phospholipids in tissues. Many cationic amphiphilic drugs, including anti-depressants, antianginal, antimalarial, and cholesterol-lowering agents, are reported to cause drug-induced phospholipidosis (DIPL) in animals and humans. The mechanisms of DIPL involve trapping or selective uptake of DIPL drugs within the lysosomes and acidic vesicles of affected cells. Drug trapping is followed by a gradual accumulation of drug-phospholipid complexes within the internal lysosomal membranes. The increase in undigested materials results in the abnormal accumulation of multi-lammellar bodies (myeloid bodies) in tissues.

It is not possible to predict which tissues will be affected by DIPL in animals and humans. The use of specific in-vitro cell lines is not recommended as a means of gate-keeping for DIPL screening, only as part of an iterative process. An in-vivo screening platform, such as biomarker, is required for preclinical and clinical DIPL assessment.

The traditional method to evaluate DIPL is visual confirmation of myeloid bodies in tissues by electron microscopy. Electron microscopy has limited utility to monitor DIPL in humans because of the invasive nature of acquiring patient tissue biopsy samples. A qualified biomarker of DIPL in the blood or urine is needed to provide a more routine, non-invasive, and cost effective means to monitor DIPL in the clinic.