Foreign Body Reaction to Subcutaneous Implants

Area of Science:

• Biomaterials Science
• Immunology
• Tissue Engineering

Background:

• Subcutaneous implants trigger a foreign body reaction (FBR) involving protein adsorption, inflammation, and fibrous encapsulation.
• This FBR can compromise implant function, affecting drug delivery and device longevity.
• The cellular and molecular mechanisms of FBR are complex and not fully understood.

Purpose of the Study:

• To review the mechanisms of the foreign body reaction to subcutaneous implants.
• To discuss current and emerging strategies for negating the foreign body reaction.
• To evaluate the efficacy of different therapeutic approaches.

Main Methods:

• Literature review of studies on foreign body reaction to implants.
• Analysis of cellular and molecular dynamics involved in FBR.
• Evaluation of therapeutic strategies including drug delivery and surface modifications.

Main Results:

• Macrophages play a key role in FBR, with differential activation states influencing the response.
• Species-specific differences exist in collagen deposition and fibrosis timing.
• Corticosteroids, particularly dexamethasone, are widely used to prevent inflammation and fibrosis.
• Surface modifications to reduce protein adsorption show promise in minimizing FBR.
• Combination therapies, such as hydrophilic coatings with dexamethasone, demonstrate high efficacy.

Conclusions:

• The foreign body reaction is a multifaceted biological response impacting implant performance.
• Corticosteroids offer broad-spectrum action against FBR components.
• Combined approaches, integrating surface engineering and targeted drug delivery, represent the most effective strategy for managing FBR.