The Foreign Body Response Demystified

Abstract

The human body is endowed with an uncanny ability to distinguish self from foreign. The implantation of a foreign object inside a mammalian host activates complex signaling cascades, which lead to biological encapsulation of the implant. This reaction by the host system to a foreign object is known as foreign body response (FBR). Over the last few decades, it has been increasingly important to have a deeper insight into the mechanisms of FBR is needed to develop biomaterials for better integration with living systems. In the light of recent advances in tissue engineering and regenerative medicine, particularly in the field of biosensors and biodegradable tissue engineering scaffolds, the classical concepts related to the FBR have acquired new dimensions. The aim of this review is to provide a holistic view of the FBR, while critically analyzing the challenges, which need to be addressed in the future to overcome this innate response. In particular, this review discusses the relevant experimental methodology to assess the host response. The role of erosion and degradation behavior on FBR with biodegradable polymers is largely explored. Apart from the discussion on temporal progression of FBR, an emphasis has been given to the design of next-generation biomaterials with favorable host response.

Processing methods for making porous bioactive glass‐based scaffolds—A state‐of‐the‐art review

“…42 According to the orientation of water molecules, proteins can either remain in their native state, thus leading to a constructive interaction with cells, or can denature, with negative effects on cells. 43 A critical review on the major theories illustrating the FBR and the ways to control it for therapeutic purposes in contact with biomaterials was recently provided by Chandorkar et al 44…”

Synergistic Material-Topography Combinations to Achieve Immunomodulatory Osteogenic Biomaterials

“…[11], [12], [13] The ability to tune or modulate the foreign-body response to a biomaterial is an ongoing challenge in the field of regenerative medicine. [14] This is further complicated when designing materials for tasks such as induction of osteogenic differentiation of hMSCs at the site of implantation. Surface chemistry [15], [16] and surface topography [17], [18], [19] have both been shown to enhance differentiation and proliferation of stem cells yet, to our knowledge, no biomaterials have been reported capable of simultaneously directing differentiation of hMSCs and polarizing macrophages towards an M2 state.…”

“…Previous TopoChip screens using hMSCs revealed a similar range of cell morphological responses, where more elongated cells were linked to ALP upregulation. [14] To explore the range and identify trends it is useful to plot all the results as both heatmaps and to rank order all results to see the range for all ChemoTopo units (see Figure S7 and Figure S8 a-b). For an exploratory method we indicate the combinations which were determined to have p-value < 0.05 from a two independent sample equal variance t-test, although we note that the sample sizes are small here and this does not account for the multiple comparisons problem.…”

Surface Modification Strategies to Improve the Osseointegration of Poly(etheretherketone) and Its Composites

“…Instead of anchoring to the surrounding bone through a process called osseointegration, PEEK and CFR‐PEEK implants tend to become encapsulated by fibrous tissue and/or colonized by bacteria as a result of the foreign body reaction that occurs post‐implantation ( Figure 1 ). Since PEEK implants do not bind directly to the bone, they are not stable and can migrate; this poor stability can be exacerbated in patients suffering from osteoporosis whose bone mass and quality are already poor . Furthermore, PEEK and CFR‐PEEK surfaces are highly susceptible to bacterial adhesion, which increases the risk of infection around the implants .…”