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![Adaptive immune response overview showing branches of the humoral (left) and cell-mediated (right) responses. Figure shows interaction between the two, represented by where the peripheral tolerance mechanism of Th cell costimulates the B cells for antibody release (see dotted arrows from cellmediated immunity to humoral immunity). Image adapted from Keogan et al. ([26], p.11).](profile/Stephie-Loncar-2/publication/369350797/figure/fig2/AS:11431281136841960@1680580038918/Adaptive-immune-response-overview-showing-branches-of-the-humoral-left-and.png)
Adaptive immune response overview showing branches of the humoral (left) and cell-mediated (right) responses. Figure shows interaction between the two, represented by where the peripheral tolerance mechanism of Th cell costimulates the B cells for antibody release (see dotted arrows from cellmediated immunity to humoral immunity). Image adapted from Keogan et al. ([26], p.11).
Source publication
Understanding factors that affect bone response to trauma is integral to forensic skeletal analysis. It is essential in forensic anthropology to identify if impaired fracture healing impacts assessment of post-traumatic time intervals and whether a correction factor is required. This paper presents a synthetic review of the intersection of the lite...
Context in source publication
Context 1
... humoral immunity and cell-mediated immunity [24]. These systems mutually function to recognise, destroy and create long-term immunity to the invading pathogen [23]. Survival and further differentiation of lymphocytes are dependent on the recognition of an antigen [24]. Fig. 2 summarises the humoral and cell mediated immune ...
Citations
... Helper CD4 + T cells are characterized by their cytokine profiles and further differentiate into Th1, Th2, Th9, Th17, or Th22 cells depending on stimuli. Th1 and Th2 can produce cytokines that can act as both pro-and anti-inflammatory factors depending on the timing of secretion during fracture healing; they secrete IFNγ, IL-4, IL-13, IL-18, and IL-33 among others which promotes bone formation by stimulating osteoblast differentiation and by inhibiting osteoclast activity [54,55]. Th9 cells express IL-9 and while the role of IL-9 in fracture healing is yet unknown, we have recently reported IL-9 to be present within the fracture callus and Elyaman et al. have reported that IL-9 initiates CD4 + cell differentiation to Th17 cells [51•, 56, 57]. ...
Purpose of Review
The purpose of this review is to summarize what is known in the literature about the role inflammation plays during bone fracture healing. Bone fracture healing progresses through four distinct yet overlapping phases: formation of the hematoma, development of the cartilaginous callus, development of the bony callus, and finally remodeling of the fracture callus. Throughout this process, inflammation plays a critical role in robust bone fracture healing.
Recent Findings
At the onset of injury, vessel and matrix disruption lead to the generation of an inflammatory response: inflammatory cells are recruited to the injury site where they differentiate, activate, and/or polarize to secrete cytokines for the purposes of cell signaling and cell recruitment. This process is altered by age and by sex.
Summary
Bone fracture healing is heavily influenced by the presence of inflammatory cells and cytokines within the healing tissue.
Graphical Abstract
... Therefore, it is crucial to identify the molecular mechanisms by which osteoblasts and the immune system interact. In addition, bone injury patients with concomitant autoimmune diseases are commonly seen in the clinic, and autoimmunity may affect bone healing [132]. Future research advances could personalize microenvironmental therapies to address the need for clinical treatment. ...
Treatment of large bone defects represents a great challenge in orthopedic and craniomaxillofacial surgery. Traditional strategies in bone tissue engineering have focused primarily on mimicking the extracellular matrix (ECM) of bone in terms of structure and composition. However, the synergistic effects of other cues from the microenvironment during bone regeneration are often neglected. The bone microenvironment is a sophisticated system that includes physiological (e.g., neighboring cells such as macrophages), chemical (e.g., oxygen, pH), and physical factors (e.g., mechanics, acoustics) that dynamically interact with each other. Microenvironment-targeted strategies are increasingly recognized as crucial for successful bone regeneration and offer promising solutions for advancing bone tissue engineering. This review provides a comprehensive overview of current microenvironment-targeted strategies and challenges for bone regeneration and further outlines prospective directions of the approaches in construction of bone organoids.
