Fig. 1

Age-related changes to macrophages during musculoskeletal repair and cancer . Following musculoskeletal injury or tumor growth, there may be changes associated with tissue-resident macrophages and tissue site during ageing (1). This may lead to decreased or altered chemotactic signals (2), driven by factors such as CSF-1, CCL2 or CCL5. Bone marrow and splenic myeloid cells are increased during ageing (3) and can supply macrophages to the tumor and injury site, however this could be further impacted by inflammageing factors such as TNF, IL-1β and IL-6. Macrophages during ageing generally display reduced capacity for phagocytosis (4). This may lead to altered transitioning from pro-inflammatory to reparative macrophages (5), which can also be driven by factors such as IL-4, IL-10 and TGF-β1. Studies are conflicting during ageing as to whether there are increased or decreased macrophages following musculoskeletal injury or during tumor growth (6). Age-associated changes are shown as increased (↑); decrease (↓); unknown (?). This Figure was created with BioRender.com