Nickel ions inhibit α-actin expression and decrease aspect ratio of rat vascular smooth muscle cells in vitro.

Area of Science:

• Biomaterials Science
• Cell Biology
• Medical Device Research

Background:

• Traditional in vitro biocompatibility testing involves direct material-sample cell culture.
• Evaluating metallic biomaterials requires understanding ion release and cellular effects.
• Nitinol is a common metallic biomaterial used in endovascular stents.

Purpose of the Study:

• To develop a novel in vitro method for assessing metallic biomaterial biocompatibility.
• To quantify nickel ion concentrations released from Nitinol.
• To correlate ion concentrations with vascular smooth muscle cell responses.

Main Methods:

• Corrosion of Nitinol wires to create conditioned media.
• Quantification of released metallic ion concentrations.
• Cell culture of vascular smooth muscle cells exposed to varying ion concentrations.
• Assessment of cell morphology (aspect ratio) and alpha-actin expression via immunostaining.

Main Results:

• Nickel ions released from Nitinol induced morphological changes in vascular smooth muscle cells, suggesting a shift to a synthetic phenotype.
• Alpha-actin expression decreased by approximately 26% at high nickel ion concentrations, indicating impaired contractile function.
• Cell proliferation remained unaffected by the tested ion concentrations.

Conclusions:

• The study presents a reproducible method for metallic biomaterial biocompatibility testing based on ion concentration.
• Nickel ion release from Nitinol can negatively impact vascular smooth muscle cell function, specifically contractility.
• Further research is needed to fully understand the long-term implications of these findings for endovascular stent performance.