Regenerative Medicine Strategies in Biomedical Implants.

PURPOSE OF REVIEW: Recently, significant progress has been made in the research related to regenerative medicine. At the same time, biomedical implants in orthopedics and dentistry are facing many challenges and posing clinical concerns. The purpose of this chapter is to provide an overview of the clinical applications of current regenerative strategies to the fields of dentistry and orthopedic surgery. The main research question in this review is: What are the major advancement strategies in regenerative medicine that can be used for implant research? RECENT FINDINGS: The implant surfaces can be modified through patient-specific stem cells and plasma coatings, which may provide methods to improve osseointegration and sustainability of the implant. Overall understanding from the review suggesting that the outcome from the studies could lead to identify optimum solutions for many concerns in biomedical implants and even in drug developments as a long-term solution to orthopedic and dental patients.

Wear particles induce a new macrophage phenotype with the potential to accelerate material corrosion within total hip replacement interfaces.

Evidence that macrophages can play a role in accelerating corrosion in CoCrMo alloy in total hip replacement (THR) interfaces leads to questions regarding the underlying cellular mechanisms and immunological responses. Hence, we evaluated the role of macrophages in corrosion processes using the cell culture supernatant from different conditions and the effect of wear particles on macrophage dynamics. Monocytes were exposed to CoCrMo wear particles and their effect on macrophage differentiation was investigated by comparisons with M1 and M2 macrophage differentiation. Corrosion associated macrophages (MCA macrophages) exhibited upregulation of TNF-α, iNOS, STAT-6, and PPARG and down-regulation of CD86 and ARG, when compared to M1 and M2 macrophages. MCA cells also secreted higher levels of IL-8, IL-1ß, IL-6, IL-10, TNF-α, and IL-12p70 than M1 macrophages and/or M2 macrophages. Our findings revealed variation in macrophage phenotype (MCA) induced by CoCrMo wear particles in generating a chemical environment that induces cell-accelerated corrosion of CoCrMo alloy at THR modular interfaces. STATEMENT OF SIGNIFICANCE: Fretting wear and corrosion within the implant's modular taper junction are prominent causes of implant failure, as they promote the release of corrosion products and subsequent development of adverse local tissue reactions. Being a multifactorial process, several in vitro models have been developed to recreate the in vivo corrosion process, often summarized as mechanically-assisted crevice corrosion. Considering the excellent corrosion properties of CoCrMo alloy, the severity of chemically-generated damage observed at the modular interface has been surprising and poorly understood. The aim of the current study is to provide a better understanding of macrophages and their plasticity at the THR taper interface when they encounter wear debris from CoCrMo alloy. This is a preliminary study along the path towards determining the mechanism(s) of CAC.