Dissecting the sequential interaction between biodegradable magnesium implants and soft tissues in vivo

• Magnesium-based biomaterials are developed with the intention to enable tissue regeneration while being degraded under physiological conditions and eventually eliminated from the body. Once in contact with tissues, the biodegradability and the biocompatibility of magnesium implants (Mg) are governed by the direct interactions with their immediate milieu. The precise mechanisms through which the soft tissue micro-environment shapes the behaviour of Mg and the host-response remain elusive. Here, it is demonstrated that Mg degradation modulates the initial acute immune response and the subsequent fibrous encapsulation upon subcutaneous implantation in rats monitored at 1-, 3-, 6-, 14- and 28-days following surgery. In comparison to titanium implants (Ti), the initial profuse release of Mg degradation products activates pro-inflammatory pathways through increased recruitment of inflammatory cells to the soft tissue/implant interface and upregulation of pro-inflammatory genes, in parallel with a superior neo-angiogenesis and vascularization at Mg. After 6d, a shift in Mg degradation kinetics dissipates the initial pro-inflammatory response and facilitates the assembly of a comparatively thinner fibrous tissue capsule than around Ti. The reduction in the fibrous encapsulation around the Mg implant aligns with a superior expression of anti-fibrotic marker FOXO-1 at the tissue interface with Mg versus Ti. Mg induce an initial potent yet transient inflammatory response, which is associated with less adverse fibrous encapsulation after tissue healing. Tailoring Mg with controlled initial degradation appears to be crucial to enabling a successful coupling between inflammation and tissue repair during the early host response to Mg.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinsk bioteknologi -- Biomaterialvetenskap (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Medical Biotechnology -- Biomaterials Science (hsv//eng)

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