Serum markers of cardiac complications in a systemic sclerosis cohort

Sex-specific difference in cardiac function in patients with systemic sclerosis: association with cardiovascular outcomes

BACKGROUND

Cardiovascular involvement is one of the leading causes of mortality in systemic sclerosis (SSc) and is reported to be higher in men as compared with women. However, the cause of this difference is largely unknown. The objective of this study was to assess sex differences in echocardiographic characteristics, including left ventricular global longitudinal strain (LV GLS), as a potential explanation of sex differences in outcomes.

METHODS

A total of 746 patients with SSc from four centres, including 628 (84%, 54±13 years) women and 118 (16%, 55±15 years) men, were evaluated with standard and advanced echocardiographic examinations. The independent association of the echocardiographic parameters with the combined endpoint of cardiovascular events-hospitalisation/death was evaluated.

RESULTS

Men and women with SSc showed significant differences in disease characteristics and cardiac function. After adjusting for the most important clinical characteristics, while LV ejection fraction and diastolic function were not significantly different anymore, men still presented with more impaired LV GLS as compared with women (-19% (IQR -20% to -17%) vs -21% (IQR: -22% to -19%), p<0.001). After a median follow-up of 48 months (IQR: 26-80), the combined endpoint occurred in 182 patients. Men with SSc experienced higher cumulative rates of cardiovascular events-hospitalisation/mortality (χ2=8.648; Log-rank=0.003), and sex differences were maintained after adjusting for clinical confounders, but neutralised when matching the groups for LV GLS.

CONCLUSION

In patients with SSc, male sex is associated with worse cardiovascular outcomes even after adjusting for important clinical characteristics. LV GLS was more impaired in men as compared with women and potentially explains the sex difference in cardiovascular outcomes.

Serum markers in systemic sclerosis with cardiac involvement

Cardiac involvement in systemic sclerosis is a common clinical entity that may range from subclinical to life-threatening complications. The classification of cardiac involvement may be expressed as either primary or secondary involvement. Primary systemic sclerosis heart involvement (SSc-pHI) refers to cardiac pathologies primarily ascribed to systemic sclerosis rather than concomitant conditions like ischemic heart disease and pulmonary hypertension. The timely recognition of cardiac involvement holds significant clinical relevance. Therefore, numerous screening or diagnostic tools have been evaluated to forecast the likelihood of cardiac involvement, particularly in the absence of clinically evident cardiac symptoms. Of these modalities, serum biomarkers are often preferred due to their expeditiousness and non-invasive nature. Hence, the crucial goal of this narrative review is to review serum biomarkers that can be a valuable or promising tool in diagnosing cardiac involvement, especially SSc-pHI, in the early stages or predicting disease prognosis.

The clinical characteristics and outcomes of patients with systemic sclerosis with myocardial involvement

BACKGROUND

Myocardial involvement (MI) is the primary cause of death in patients with systemic sclerosis (SSc). We analyzed patients with SSc and MI to identify their characteristics and outcome.

METHOD

We retrospectively collected data from SSc patients with MI admitted to Peking Union Medical College Hospital between January 2012 and May 2021. SSc patients without MI were randomly selected as controls after matching age and gender at a ratio of 1:3.

RESULTS

In total, 21 SSc patients (17 females) with MI were enrolled. The mean age at SSc onset was 42.3 ± 15.1 years old. Compared with controls, myositis (42.9% vs. 14.3%, P = 0.014) and elevation of CK (33.3% vs. 4.8%, P = 0.002) were more common in patients with MI. Of the 7 patients without cardiovascular symptoms, 3 /5 showed elevations in cardiac troponin-I (cTnI), 6 showed elevations of N-terminal brain natriuretic peptide (NT-proBNP). Eleven patients were followed up for a median period of 15.5 months and four patients developed newly occurring left ventricular ejection fraction (LVEF) < 50%.

CONCLUSION

One third of SSc patients with MI were asymptomatic. Regular monitoring of CTnI, NT-proBNP and echocardiography is helpful for the diagnosis of MI during the early stages. Its prognosis is poor.

Target organ expression and biomarker characterization of chemokine CCL21 in systemic sclerosis associated pulmonary arterial hypertension

Introduction

Systemic sclerosis (SSc) is a heterogenous disorder that appears to result from interplay between vascular pathologies, tissue fibrosis and immune processes, with evidence for deregulation of chemokines, which normally control immune trafficking. We recently identified altered levels of chemokine CCL21 in SSc associated pulmonary arterial hypertension (PAH). Here, we aimed to define target organ expression and biomarker characteristics of CCL21.

Materials and methods

To investigate target organ expression of CCL21, we performed immunohistochemistry (IHC) on explanted lung tissues from SSc-PAH patients. We assessed serum levels of CCL21 by ELISA and Luminex in two well-characterized SSc cohorts from Oslo (OUH, n=552) and Zurich (n=93) University hospitals and in 168 healthy controls. For detection of anti-CCl21 antibodies, we performed protein array analysis applying serum samples from SSc patients (n=300) and healthy controls. To characterize circulating CCL21 in SSc, we applied immunoprecipitation (IP) with antibodies detecting both full length and tailless and a custom-made antibody detecting only the C-terminal of CCL21. IP products were analyzed by SDS-PAGE/western blot and Mass spectrometry (MS).

Results

By IHC, we found that CCL21 was mainly expressed in the airway epithelial cells of SSc patients with PAH. In the analysis of serum levels of CCL21 we found weak correlation between Luminex and ELISA (r=0.515, p<0.001). Serum levels of anti-CCL21 antibodies were higher in SSc patients than in healthy controls (p<0.001), but only 5% of the SSc population were positive for anti-CCL21 antibodies in SSc, and we found no correlation between anti-CCl21 and serum levels of CCL21. By MS, we only identified peptides located within amino acid (aa) 23-102 of CCL21, indicating that CCL21 in SSc circulate as a truncated protein without the C-terminal tail.

Conclusion

This study demonstrates expression of CCL21 in epithelial lung tissue from SSc patients with PAH, and indicate that CCL21 in SSc circulates as a truncated protein. We extend previous observations indicating biomarker potential of CCL21, but find that Luminex is not suitable as platform for biomarker analyses. Finally, in vivo generated anti-CCL21 antibodies exist in SSc, but do not appear to modify serum CCL21 levels in patients with SSc-PAH.