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International Journal of Bioprinting G40T60@WNT5A promotes osteoblast differentiation

1. Introduction a platform for improving the compatibility of prostheses
with bone defects and enabling the restoration of
Chronic osteomyelitis is a serious complication of bone stability. 19-21 Varying degrees of bone defects are
orthopedic surgery. After the surgery, the severe damage the frequently encountered challenges in bone joint
1
to the periosteum at the lesion caused by inflammation remodeling surgeries. Nevertheless, 3D-printed models
weakens the ability to form bone, leading to bone necrosis could help restore the anatomical structure of bone
2
and long-segment bone defects. Chronic osteomyelitis joints and assist surgeons to better understand the 3D
presents with extensive scarring, sinuses, necrotic bone, morphology of bone joints, in addition to other apparent
and dead spaces. Adding to the severity of the condition advantages such as increased efficiency and stability of
is the poor local blood circulation, which restricts prosthetic matching and reduced surgical difficulty.
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antimicrobial drugs to reach the affected area, thereby Besides, surgeons may formulate treatment plans, perform
promoting bacterial growth and subsequently leading to surgical rehearsal, and conduct evaluation using these
recurrent infections. Thus, these issues pose a challenge in models. Therefore, 3D printing stands as an obvious
clinical practice. Chronic osteomyelitis usually occurs in solution in the creation of customized prosthetics in the
3-5
adults and is typically secondary to open bone injuries or case of significant bone defects. Recently, owing to their
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bone reconstruction surgery. 6,7
favorable biocompatibility and bioactivity, there has been
In 1965, Gavriil Ilizarov proposed a theory known growing interest in biodegradable materials, which are
as “tension-stress principle,” based on which the Ilizarov used to promote bone tissue regeneration and repair.
technique for bone sliding was conceptualized, which has Biodegradable polymers have been widely applied in
been the preferred method for treating tibial bone defects various functions, such as drug delivery, biomedicine, 3D
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and nonunion since then. 8-11 Surgical debridement and printing, food packaging, enzyme immobilization, tissue
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bone grafting are conventional approaches for treating engineering scaffolds, nanotechnology, and technological
chronic osteomyelitis with bone defects. However, for applications. Biodegradable polymers can be generally
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patients with longer defect lengths, the difficulty in bone classified into two categories: synthetic polymers and
reconstruction is increased due to significant bone loss, natural polymers. Synthetic polymers are compatible
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resulting in often unsatisfactory patient outcomes. The with the human body, can undergo biodegradation, and
12
Masquelet technique could produce a satisfactory induced can be easily transformed into different 3D structures. On
membrane when bone cement is placed on the infection- the other hand, natural polymers can be metabolized into
free surgical area, targeting bone defects caused by utilizable metabolites or easily cleared by the kidneys. A
thorough debridement and various factors. 13,14 Moreover, few noteworthy advantages of biodegradable polymers
the implantation of autologous bone has relatively fewer include reduced inflammatory reactions, non-toxicity,
limitations in terms of length, which gives it a significant and the ability to degrade enzymatically in the body. He
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advantage over other techniques when dealing with large et al. discovered that 3D-printed biodegradable PU/
segmental bone defects. The implantation of autologous PAAM/Gel hydrogel scaffolds exhibit high flexibility
bone also enhances patients’ medical experience and and adaptive capacity for irregular defects, making them
facilitates nursing care and rehabilitation. 14-16 However, suitable for non-load-bearing bone regeneration. Chen et
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several limitations of using traditional Masquelet technique al. found that 3D-printed scaffolds can direct extracellular
in bone cement filling should be acknowledged. In the matrix/stromal stem cells for bone and cartilage
traditional in vivo shaping method, the bone defect is filled defect regeneration. 32
with bone cement before it solidifies and wraps around the According to previous research, WNT5A is closely
fracture ends for natural solidification. The solidification related to osteogenic differentiation. Some studies have
process is started during the second stage surgery once reported that microvesicles derived from adipocytes could
the bone cement becomes firmly connected to the bone inhibit osteogenic differentiation by secreting miR-148a,
ends; however, given its relatively large size, removal of which targets and regulates the Wnt5a/Ror2 pathway. 33-36
the bone cement would introduce damages to the induced In addition, it was found that activation of Wnt5a could
membrane and the interface between the bone cement and mediate the mechanical stretch-induced osteogenic
bone tissue, thus affecting fracture healing in the second- differentiation of mesenchymal stem cells. WNT5A is
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stage bone grafting. Additionally, the heat released during also associated with angiogenesis. Research has found that
the solidification process of the bone cement can also antagonizing the Wnt/β-catenin signaling pathway could
damage adjacent bone and tissues. 17,18
inhibit endothelial cell proliferation, tube formation, and
With the increasing application of three-dimensional migration as well as induce endothelial cell apoptosis,
(3D) printing in orthopedics, this technology provides thereby suppressing endothelial cell angiogenesis. 38

Volume 10 Issue 2 (2024) 229 doi: 10.36922/ijb.1461