A cross-disciplinary University of Alberta research team has uncovered a biological marker for scleroderma that can predict which patients will develop severe disease and could also lead to new treatments.
Scleroderma is a rare condition that affects about 17,000 people in Canada. An overproduction of collagen leads to a hardening of the skin, and in severe cases, blood vessels and internal organs are also affected. Approximately 40 per cent of patients die within five years of diagnosis.
Medication, diet and exercise may slow progression and ease symptoms, but there is no cure, and until now there has been no way to predict who will develop the most severe form of the disease.
In recently published research, the team found that polysialic acid is elevated in both the skin and blood of patients with systemic sclerosis and correlates with the level of fibrosis. Polysialic acid is a glycan, or sugar modification, on the surface of cells in the immune, reproductive and nervous systems, and is known to be associated with aggressive cancer cells as well.
"Scleroderma is a terrible disease that starts with debilitating fatigue and then leads to systemic scarring. Imagine basically feeling trapped in your own body," says co-principal investigator Mo Osman, rheumatologist and immunologist and associate professor in the Faculty of Medicine & Dentistry.
"It's key to identify those whose disease will progress because we want to be able to treat them early to minimize damage," Osman says.
Co-principal investigator Lisa Willis, assistant professor in the Faculty of Science and an expert on glycans, developed the blood test for polysialic acid in her lab.
"What you need for a biomarker is something that can be used cheaply in a clinic," Willis says. "We developed our test to be able to look for our molecule from the vial of blood that was already taken from a patient at diagnosis."
Although scleroderma is generally considered an inflammatory autoimmune disorder, it often does not respond to treatments that suppress the immune system. About three patients a year in Edmonton receive a stem cell transplant to replace bone marrow that's not working properly. The treatment costs about $80,000 per patient and requires patients to go to Calgary for three months, Osman says.
The researchers reported that patients who had received a bone marrow transplant showed reduced levels of polysialic acid, an indicator that changes in the glycan are directly related to the disease process.
For the study, blood and tissue samples were taken from five healthy control patients, five patients with skin fibrosis only, 11 patients with more severe fibrosis and four patients who had received transplants.
Willis and Osman had not worked together before, but both were struck by previously observed similarities between scleroderma and cancer.
"This is the most exciting type of science," says Osman. "We thought, 'It's very interesting that immune cells in scleroderma behave very similarly to immune cells in cancer, so what's going on? Maybe there's a connection.'"
Willis says they postulate that the glycan is interfering with the body's ability to deal with scarring.
