title: Role of inflammation in the aging bones.
abstract: Chronic inflammation in aging is characterized by increased inflammatory cytokines, bone loss, decreased adaptation, and defective tissue repair in response to injury. Aging leads to inherent changes in mesenchymal stem cell (MSC) differentiation, resulting in impaired osteoblastogenesis. Also, the pro-inflammatory cytokines increase with aging, leading to enhanced myelopoiesis and osteoclastogenesis. Bone marrow macrophages (BMMs) play pivotal roles in osteoblast differentiation, the maintenance of hematopoietic stem cells (HSCs), and subsequent bone repair. However, during aging, little is known about the role of macrophages in the differentiation and function of MSC and HSC. Aged mammals have higher circulating pro-inflammatory cytokines than young adults, supporting the hypothesis of increased inflammation with aging. This review will aid in the understanding of the potential role(s) of pro-inflammatory (M1) and anti-inflammatory (M2) macrophages in differentiation and function of osteoblasts and osteoclasts in relation to aging.
authors.affiliation: Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, OH 44272, USA.
authors.forename: Samir M
authors.initials: SM
authors.lastname: Abdelmagid
authors.affiliation: Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Mary F
authors.initials: MF
authors.lastname: Barbe
authors.affiliation: Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, OH 44272, USA; School of Biomedical Sciences, Kent State University, Kent, OH 44240, USA. Electronic address: fayez.safadi@neomed.edu.
authors.forename: Fayez F
authors.initials: FF
authors.lastname: Safadi
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001854:Bone Marrow Cells / Q000502:physiology; D001842:Bone and Bones / Q000166:cytology / Q000276:immunology / Q000503:physiopathology*; D002454:Cell Differentiation / Q000502:physiology*; D012090:Cumulative Trauma Disorders / Q000503:physiopathology; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D008264:Macrophages / Q000502:physiology*; D008954:Models, Biological; D010006:Osteoblasts / Q000502:physiology*; D010010:Osteoclasts / Q000502:physiology*
keywords: Aging; Bone adaptation; Bone resorption; Inflammation; Macrophages; Osteoblasts; Osteoclasts