Background: Systemic sclerosis (SSc) is a female-predominant disease, characterized by excessive extracellular matrix deposition (ECM) with dermal and internal organ fibrosis. Considering the sex-based disparity in disease incidence, estradiol (E2), an estrogen form with pro-fibrotic effects, may play a role in SSc. We reported that post-menopausal women with diffuse cutaneous (dc)SSc have higher serum E2 levels compared to similar aged, healthy controls. Since males with SSc tend to have more severe disease, we examined serum E2 in dcSSc males in relation to disease characteristics and survival.
Methods: We measured serum E2 in 83 dcSSc men > 50 years old from the University of Pittsburgh Scleroderma Center and similar aged healthy controls. Using statistical modeling, we examined the associations between serum E2, internal organ involvement, autoantibody profiles, and survival.
Results: Male dcSSc patients had significantly higher serum E2 levels compared to healthy males and similar aged dcSSc post-menopausal women. Male dcSSc patients with high serum E2 had significantly more heart involvement, a trend for higher skin thickness progression rate, and worse survival. Using Cox regression modeling, increased serum E2 levels in anti-Scl-70 antibody-positive dcSSc males were associated with an increased risk of death.
Conclusions: dcSSc males > 50 years old have higher levels of serum E2 compared to healthy controls and dcSSc post-menopausal women. Elevated serum E2 levels in dcSSc males are associated with heart involvement, trend to progression of dermal fibrosis, and, if anti-Scl-70 antibody positive, worse survival. Our study expands on previous work implicating E2 in dermal fibrosis in SSc and associates E2 levels with internal organ involvement and survival. These data suggest a role for estrogen imbalance in dcSSc.
Keywords: Estrogen; Fibrosis; Survival; Systemic sclerosis.