Osteolysis in Systemic Sclerosis: A Scoping Review

High-resolution peripheral quantitative computed tomography for the assessment of acro-osteolysis and calcinosis in patients with systemic sclerosis

OBJECTIVE

To assist the development of future treatments in systemic sclerosis (SSc), the development of reliable outcome measures is pivotal. We aimed to evaluate the use of high-resolution peripheral quantitative CT (HR-pQCT) for visualization and gradation of acro-osteolysis (AO) and calcinosis compared to conventional hand radiographs (CR) in patients with SSc.

METHODS

HR-pQCT scans of the 2nd to 4th fingers, CR, nail fold capillaroscopy, and a clinical examination were conducted. Images were reviewed for the presence and degree of AO and calcinosis according to semiquantitative grading scales.

RESULTS

Forty patients were included. Fourteen had AO according to CR, whereas HR-pQCT revealed AO in 18 patients. The sensitivity and specificity of classifying patients as having AO by HR-pQCT when CR was used as reference were 93% (95% CI: 66-99%) and 80% (95% CI: 59-93%), respectively. By CR and with HR-pQCT as reference, the sensitivity and specificity were 72% (95% CI: 47-90%) and 95% (95% CI: 76-99%). Patients with AO had more or larger calcifications than patients without AO according to the proposed HR-pQCT grading system, with a median grade of 2 (IQR: 1-3) versus 0 (IQR: 0-1) (P<0.01). Grade 3 changes were observed exclusively in patients with AO (n=6/14, 42.9%). Assessment of AO and calcinosis by HR-pQCT demonstrated moderate to excellent test-retest reliability.

CONCLUSION

HR-pQCT allowed precise and reliable classification and grading of acro-osteolysis and acral calcinosis. The modality could prove helpful for detecting and monitoring these lesions as well as facilitating early diagnosis and guide treatment of these patients.

Protein profiling in systemic sclerosis patients with different pulmonary complications using proteomic antibody microarray

BACKGROUND

Pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD) are leading causes of systemic sclerosis (SSc)-related death. In this study, we aimed to identify biomarkers for detecting SSc pulmonary complications that are mild and in the early stages to improve the prognosis.

METHODS

We screened for serum biomarkers using a proteomic antibody microarray that simultaneously assessed 1000 proteins. Differentially expressed proteins were further verified using ELISA. Finally, we performed a correlation analysis using clinical data.

RESULTS

We identified 125 differentially expressed proteins, of which calcitonin, sclerostin (SOST), CD40, and fibronectin were selected for further verification. Serum calcitonin and SOST levels were significantly elevated in all SSc pulmonary complication subgroups, whereas serum calcitonin levels were higher in the SSc with PAH subgroup than in the SSc without PAH and ILD subgroup. Serum SOST levels were possibly associated with the presence of ILD and positively related to the presence of cardiac and gastrointestinal involvement. Serum CD40 and calcitonin levels appeared to be positively related to the presence of renal involvement, and serum calcitonin was also positively related to the presence of gastrointestinal involvement.

CONCLUSIONS

This study indicated that serum calcitonin and SOST levels may be promising biomarkers for SSc-related PAH and ILD, respectively. Further research is needed to verify this result and understand the underlying mechanisms.