Elevated marrow inflammatory cells and osteoclasts in subchondral osteosclerosis in human knee osteoarthritis

Abstract

Subchondral osteosclerosis, characterized by an increase of hypomineralized bone material, is a pathological hallmark of osteoarthritis. The cellular components in the subchondral marrow compartment that participate in this aberrant bone remodeling process remain to be elucidated. This study assessed the presence of marrow inflammatory cells and their relative abundance between nonsclerotic and sclerotic tissues in knee osteoarthritis. Bone samples from osteoarthritic knee tibial plateaus were stratified for histological analyses using computed tomography osteoabsorptiometry. Immunohistological analysis revealed the presence of CD20 (Blymphocyte) and CD68 (macrophage), but not CD3 (T-lymphocyte) immunoreactive mononuclear cells in subchondral marrow tissues and their relative abundance was significantly increased in sclerotic compared with nonsclerotic bone samples. Multinucleated osteoclasts that stained positive for CD68 and tartrate-resistant acid phosphatase, predominantly associated with CD34-positive blood vessels and their abundance was strongly increased in sclerotic samples. Bone-specific alkaline phosphatase activity in outgrowth osteoblasts was induced by conditioned medium from nonsclerotic, but not sclerotic, bone pieces. These results suggest that an interaction between bone-resident cells and marrow inflammatory cells might play a role in aberrant bone remodeling leading to subchondral osteosclerosis. Elevated osteoclast activity in sclerotic bone suggests that bone formation and resorption activities are increased, yet uncoupled, in human knee osteoarthritis. ß

Focal Defects of the Knee Articular Surface: Evidence of a Regenerative Potential Pattern in Osteochondritis Dissecans and Degenerative Lesions

“…These data are in line with studies by Krause et al [3] and Yonetani et al [26] who also showed viable subchondral trabeculae in juvenile OCD lesions arthroscopically classified according to the International Cartilage Repair Society (ICRS) OCD as ICRS OCD I/II [27]. A recent paper described a greater presence of TRAP-positive cells in sclerotic bone than in nonsclerotic bone areas, which is a typical feature in advanced OA [28], suggesting that the presence of TRAP-positive cells in bone focal lesion may contribute to a sclerotic bone evolution.…”

Characterization of subchondral bone histopathology of facet joint osteoarthritis in lumbar spinal stenosis

“…Kim et al have also demonstrated increased CD11d‐positive cell (monocyte/macrophage) infiltration and cytokine production in capsular tissues from severely degenerated facet joints. In a previous study, we have demonstrated enhanced marrow macrophage infiltration in subchondral bone sclerosis in knee osteoarthritis . The precise pathological role of enhanced macrophage abundance needs to be established, but recent studies revealed that these cells regulate bone remodelling in health and disease …”

“…In a previous study, we have demonstrated enhanced marrow macrophage infiltration in subchondral bone sclerosis in knee osteoarthritis. 15 The precise pathological role of enhanced macrophage abundance needs to be established, but recent studies revealed that these cells regulate bone remodelling in health and disease. 34 Subchondral bone histopathology of facet joint osteoarthritis in lumbar spinal stenosis is characterized by marrow infiltration by macrophage-rich tissues and enhanced de novo bone formation.…”

“…In recent histological studies, we have demonstrated that secondary ankle OA is characterized by extensive de novo bone formation in absence of osteoclast activity . In contrast, primary knee OA subchondral bone tissues showed macrophage‐ and osteoclast‐rich marrow tissue infiltration and contained foci of B‐cells …”

“…14 In contrast, primary knee OA subchondral bone tissues showed macrophage-and osteoclast-rich marrow tissue infiltration and contained foci of B-cells. 15 Facet joint OA involves degenerative changes to multiple tissues including cartilage, bone, capsule and synovial tissues. A recent in-depth characterization of capsular tissues from degenerated facet joints, showed highly upregulated inflammatory cytokines, pain mediators, and cartilage-degrading enzymes.…”