Pannus inflammation in sacroiliitis following immune pathological injury and radiological structural damage: a study of 193 patients with spondyloarthritis

Abstract

BackgroundThe pathogenesis of sacroiliitis is unclear; therefore, we aimed to systematically study the immunopathology of sacroiliitis in patients with axial spondyloarthritis (axSpA), and explore the relationship between pannus formation, inflammation, and the structural damage caused by sacroiliitis.MethodsFine needle aspiration biopsy of the sacroiliac joint (SIJ) was performed in 193 patients with axSpA. Clinical, laboratory, and imaging data were collected at baseline and during the follow up. Immunohistochemistry analysis was performed to detect CD34+ microvessels, CD68+ osteoclasts/macrophages, vascular endothelial growth factor (VEGF), metalloproteinase-3 (MMP-3), tumor necrosis factor-α (TNF-α), and caspase-3. Autopsy subjects were used as controls.ResultsIn early sacroiliitis (grade 0–1) all pathological features could be observed, with the most common being subchondral pannus formation. Among the 193 patients, 98 were followed up for 1–13 years (mean 3.6 years); 63.3% had radiological progression at the endpoint. Multiple regression analysis showed that cartilage pannus invasion (OR 2.99, P = 0.010) and endochondral ossification (OR 3.97, P = 0.049) at baseline were risk factors for radiological structural damage. Compared to SIJ controls, the subchondral microvessel density, number of CD68+ multinuclear osteoclasts, and the levels of VEGF, caspase-3, MMP-3, and TNF-α expressed at the interface of the bone and cartilage were significantly higher in patients with sacroiliitis.ConclusionsSubchondral fibrovascular tissue formation is the most important pathological feature in early sacroiliitis. The existence of cartilage pannus invasion or endochondral ossification at baseline can predict radiological structural damage during the follow up.Electronic supplementary materialThe online version of this article (10.1186/s13075-018-1594-z) contains supplementary material, which is available to authorized users.

Quantitative DCE-MRI : An efficient diagnostic technique for evaluating early micro-environment permeability changes in ankylosing spondylitis

“…K trans , K ep and V e parameters re ect perfusion and permeability,the reverse transportation of gadolinium chelate back to the vascular space as well as extravascular extracellular space volume.In the present study,there were no signi cant differences between the model group and control group based on DCE-MRI parameters assessing in the joint space of SIJ at 12 weeks after induction.These results were consistent with the pathological results which showed no signi cant positive in ammatory changes at 12 weeks. At 17 and 22 weeks,the differences of K trans between the two groups were statistically signi cant.The previous investigations have noted that in early stages of axial SpA, pannus formation helps in understanding the associated pathological changes [25] .It is characterized by formation of high vascular granulation tissue by the in amed synovium and/or subchondral bone marrow.In ammation may subsequently trigger the formation of angiogenesis by increasing the density of the micro-vessels that provide a channel for expression of mediation and invasion of in ammatory cells and this in turn exacerbates local damage to the cartilage [26/27] .Based on pathological results,local in ltration of in ammatory tissues of the subsynoviocytic and areolar connective tissue in the early stage may led to the increase of vascular permeability. A related view is that François R J et al [28] have reported that a small number of lymphocytes and plasma cells with a large number of macrophages in ltrated the subsynoviocytic and areolar connective tissue in a systematic histological study of early SIJ.…”

Quantitative DCE-MRI: an efficient diagnostic technique for evaluating early micro-environment permeability changes in ankylosing spondylitis

“…At 17 and 22 weeks,the differences of K trans between the two groups were statistically significant. The previous investigations have noted that in early stages of axial SpA, pannus formation helps in understanding the associated pathological changes [ 25 ]. It is characterized by formation of high vascular granulation tissue by the inflamed synovium and/or subchondral bone marrow.…”

Quantitative DCE-MRI: An Efficient Diagnostic Technique for Evaluating Early Micro-environment Permeability Changes in Ankylosing Spondylitis

“…K trans , K ep and V e parameters re ect perfusion and permeability,the reverse transportation of gadolinium chelate back to the vascular space as well as extravascular extracellular space volume.In the present study,there were no signi cant differences between the model group and control group based on DCE-MRI parameters assessing in the joint space of SIJ at 12 weeks after induction.These results were consistent with the pathological results which showed no signi cant positive in ammatory changes at 12 weeks. At 17 weeks, the K trans , K ep and V e values in the model group were higher than those of the control group.However, only the differences of K trans between the two groups were statistically signi cant.The previous investigations have noted that in early stages of axial SpA, pannus formation helps in understanding the associated pathological changes [19] .It is characterized by formation of high vascular granulation tissue by the in amed synovium and/or subchondral bone marrow.In ammation may subsequently trigger the formation of angiogenesis by increasing the density of the micro-vessels that provide a channel for expression of mediation and invasion of in ammatory cells and this in turn exacerbates local damage to the cartilage [20/21] .Based on pathological results,local in ltration of in ammatory cells of the subsynoviocytic and areolar connective tissue in the early stage may led to the increase of vascular permeability. A related view is that François R J et al [22] have reported that a small number of lymphocytes and plasma cells with a large number of macrophages in ltrated the subsynoviocytic and areolar connective tissue in a systematic histological study of early SIJ.…”