title: The Paradox of Bone Formation and Bone Loss in Ankylosing Spondylitis: Evolving New Concepts of Bone Formation and Future Trends in Management.
abstract: OBJECTIVE
  The purpose of the study is to briefly review the molecular mechanisms that leads to structural damage in ankylosing spondylitis (AS), defined as new bone formation resulting in complete or incomplete ankylosis of the spine, and the impact of treatment with biologics to retard this process.
  
  
  RESULTS
  The understanding of molecular mechanisms leading to new bone formation in AS has significantly improved but is still incomplete. Availability of biologics has greatly enhanced the treatment of patients with AS, but its impact on slowing the structural damage is still a matter of debate, although a few observational studies have shown that long term use of TNF-α blockers may slow radiographic progression. The availability of newer biologics targeting IL-17/1L23 has shown some promising results in slowing radiographic progression in AS. Although the availability of TNF-inhibitors has greatly enhanced the treatment options for patients with AS, their impact on slowing the structural damage is still not clearly established. However, preliminary results using newer biologics targeting IL-17/1L23 axis are more encouraging but longer follow-up is needed.
authors.affiliation: Case Western Reserve University School of Medicine, Cleveland, OH, 44109, USA. mmagrey@metrohealth.org.|MetroHealth Medical Center, Cleveland, OH, 44109, USA. mmagrey@metrohealth.org.
authors.forename: Marina N
authors.initials: MN
authors.lastname: Magrey
authors.affiliation: Division of Rheumatology, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Khan
mesh_terms: D001688:Biological Products / Q000494:pharmacology / Q000627:therapeutic use*; D019468:Disease Management; D018450:Disease Progression; D006801:Humans; D058990:Molecular Targeted Therapy / Q000379:methods / Q000639:trends; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics*; D011859:Radiography; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000235:genetics* / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: D001688:Biological Products; D014409:Tumor Necrosis Factor-alpha
keywords: Ankylosing spondylitis; Axial spondyloarthritis; Bone morphogenetic proteins; Il-17 inhibitors; MicroRNAs; New bone formation; Osteoporosis; Osteoproliferation; Syndesmophytes; TNF-α inhibitors; Wnt signaling pathways