Plasma mitochondrial DNA is associated with extrapulmonary sarcoidosis

Area of Science:

• Immunology
• Genetics
• Pulmonology

Background:

• Sarcoidosis is an unpredictable granulomatous disease with disproportionately aggressive phenotypes in African Americans.
• Extracellular mitochondrial DNA (mtDNA) is implicated in tissue remodeling and inflammation in various diseases.
• The role of extracellular mtDNA in sarcoidosis pathogenesis and clinical presentation is currently unknown.

Purpose of the Study:

• To determine the association between extracellular mtDNA levels and clinical features of sarcoidosis.
• To investigate differences in extracellular mtDNA concentrations based on race and disease extent.

Main Methods:

• Quantitative PCR was used to measure MT-ATP6 gene concentrations in bronchoalveolar lavage (BAL) fluid and plasma samples.
• Samples were obtained from healthy controls and patients with sarcoidosis from The Yale Lung Repository.
• Associations with Scadding stage, extrapulmonary disease, and demographics were analyzed and validated in an independent cohort.

Main Results:

• MT-ATP6 concentrations were significantly elevated in BAL fluid and plasma of sarcoidosis patients compared to controls.
• Elevated MT-ATP6 levels were particularly pronounced in the plasma of patients with extrapulmonary disease.
• African American patients exhibited higher MT-ATP6 concentrations in both BAL fluid and plasma compared to Caucasian patients, with plasma levels correlating to increased odds of extrapulmonary disease.

Conclusions:

• Elevated extracellular mtDNA in sarcoidosis is associated with disease extent (extrapulmonary involvement) and African American descent.
• These findings suggest extracellular mtDNA may serve as a biomarker for disease severity and specific patient populations.
• Further research into the mechanistic role of extracellular mtDNA could unveil novel pathophysiological insights and therapeutic targets for sarcoidosis.