Alterations in human monocyte structure and function induced by incubation with gold sodium thiomalate

Area of Science:

• Immunology
• Pharmacology
• Cell Biology

Background:

• Rheumatoid arthritis is a chronic inflammatory disease.
• Mononuclear phagocytes (Mphi) play a key role in immune responses and inflammation.
• Gold sodium thiomalate (GST) is a disease-modifying antirheumatic drug used in rheumatoid arthritis treatment.

Purpose of the Study:

• To investigate the in vitro effects of gold sodium thiomalate (GST) on the morphology and function of human mononuclear phagocytes (Mphi).
• To elucidate the cellular mechanisms underlying GST's therapeutic action in rheumatoid arthritis.

Main Methods:

• Human peripheral blood Mphi were incubated with GST (25 µg/ml) for 4 days.
• Morphological changes were assessed by microscopy.
• Functional assays included measurement of glass adherence, Fc receptor-mediated particle binding, pinocytosis of horseradish peroxidase, and phagocytosis of IgG-opsonized erythrocytes.

Main Results:

• GST incubation led to the development of large intracytoplasmic vacuoles in Mphi.
• Similar vacuolization was observed with gold chloride but not thiomalic acid.
• GST significantly diminished Mphi pinocytosis and phagocytosis, while having minimal effect on adherence and Fc receptor binding.

Conclusions:

• Gold sodium thiomalate induces significant morphological and functional alterations in human mononuclear phagocytes.
• The observed effects on Mphi function, particularly reduced phagocytosis, may contribute to the therapeutic efficacy of GST in rheumatoid arthritis.
• GST's mechanism of action may involve modulating the functional capacity of Mphi.