We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Effects of Polystyrene Microplastics on Bone-Related Protein Expression, Mineralization Capacity, and Mitochondrial Function in Osteoblastlike Cells (MG-63)
Summary
Scientists found that tiny plastic particles (the kind now showing up in human bones) can get absorbed by bone-building cells and disrupt some of the proteins these cells need to properly regulate bone formation. The good news: in this lab study, the plastics didn't actually stop the cells from depositing calcium or affect their energy production, suggesting bone strength itself wasn't compromised, but the findings raise questions about long-term effects of microplastic buildup on bone health that scientists will need to investigate further.
Background: Microplastics (MPs) were recently evidenced in the human skeleton. Since bone complications are frequent in patients with CKD, understanding the role of MPs in bone has been gaining prominence. We aimed to evaluate the effects of polystyrene (PS-MPs) on bone-related protein expression, mineralization, and bioenergetics. Methods: Osteoblast-like cells (MG-63) were exposed to PS-MPs at 5-50 µg/mL. Internalization of PS-MPs was analyzed by confocal microscopy. Osteoprotegerin, osteocalcin, osteopontin, and DKK1 levels in cell lysates/supernatants were measured by MilliplexTM human bone panel. Cell mineralization was evaluated through alkaline phosphatase activity and calcium deposition. Mitochondrial function was assessed by monitoring oxygen consumption (high-resolution respirometry). Glucose consumption and lactate production were measured by colorimetric assays. Results: MG-63 internalized PS-MPs into the cytoplasm. Compared to the control, cells exposed to PS-MPs at 10 and 25 µg/mL decreased osteocalcin (137±117.6 vs. 109±8.7 pg/mL, p=0.04; and 137±117.6 vs. 100±16.9 pg/mL, p=0.03) and osteoprotegerin (8719±593.2 vs. 7402±527.7 pg/mL, p=0.04; 8719±593.2 vs. 6950±689.2 pg/mL, p=0.01) expression. DKK1 concentration was also reduced following PS exposure at 25 µg/mL (10431(8937-12003) vs. 7789±1683.3 pg/mL, p=0.04). Similar PNP production and calcium deposition were observed. No changes were observed in oxygen consumption between control and PS-MPs-treated cells. Glucose concentrations (mg/dL) in the cell culture medium at 48 h (100 mg/mL at baseline) were 40.4±21.4 for the control, 49.9±20.2 for the 5 µg/mL group, and 45.2±19 for the 50 µg/mL group (p>0.05). Lactate concentrations were significantly higher at 48 h (p<0.001) for all conditions compared to their 24-h baseline, without differences between groups. Conclusion: PS-MPs altered the expression of key bone-related proteins without affecting calcium deposition induced by alkaline phosphatase activity. No significant differences were found in bioenergetics assessed parameters.