Friedreich’s ataxia (FA) patients have elevated blood levels of a factor indicating increased collagen production, a finding that researchers could link to remodeling of heart tissue. These findings could help identify heart problems in FA patients, especially because heart conditions represent the typical cause of death in Friedreich’s ataxia.
The study, “Serum versus Imaging Biomarkers in Friedreich Ataxia to Indicate Left Ventricular Remodeling and Outcomes,” published in the Texas Heart Institute Journal, suggests that measurements of the factor could be used as a biomarker in clinical studies of heart muscle problems in Friedreich’s ataxia, complementing other methods now in use.
The left ventricle of the heart is particularly affected in patients with this type of ataxia. As muscles in the heart break down, muscle cells are replaced by fibrotic tissue. Since collagen is a key component of fibrotic tissue, abnormal collagen production is a crucial part of the molecular processes leading to changes in tissue composition and deformation of the heart.
A marker of collagen production called PICP (procollagen I carboxyterminal propeptide) can be measured in a blood sample from patients, and serve as an indicator of fibrosis.
Researchers at Ohio State University recruited 29 patients with Friedreich’s ataxia who had no history of heart symptoms, along with 29 healthy volunteers, and measured the levels of the factor.
PICP was higher among FA patients than the healthy controls, but levels of the factor could not be linked to the number of GAA base-pair repeats in the mutated frataxin gene. During the first examination, levels of PICP correlated to the extent of heart remodeling.
At a follow-up visit, researchers could no longer see this association, but higher levels during the first visit were seen in those who developed a larger dilation of the left ventricle during the 12 months of the study.
Patients were also examined with magnetic resonance imaging (MRI) of the heart to determine if their heart tissue was fibrotic.
Despite PICP being a collagen marker, the levels of the factor could not indicate if a patient had heart fibrosis.
After one year, three of the 14 patients with heart fibrosis had experienced heart problems, while none of the 15 patients had any heart symptoms by that time.
Researchers suggest that both PICP measurements should be further evaluated to determine if the method is a suitable biomarker of heart disease in Friedreich’s ataxia.