Assessment of respiratory chain function in cultured fibroblasts using cytochemistry, immunocytochemistry and SDS-PAGE

Diagnosis of mitochondrial disorders requires implementation of vast spectrum of laboratory techniques detecting respiratory chain dysfunction (RCD) in different organs and tissues. Skeletal muscle biopsy is considered the most informative in RCD diagnosis, however the procedure is invasive and muscle mitochondria are not involved in all mitochondrial diseases. Cultured skin fibroblasts may be useful due to minimally invasive character of skin biopsy, possibility to obtain large number of cultured cells, and to delay studies until new methods become available. Aim of the study was to analyze the results of cytochemical, immunocytochemical, and electrophoretic (SDS-PAGE) studies in cultured skin fibroblasts of patients with defective and unaffected respiratory chain function. Different laboratory modifications were compared. Tested methods appeared potentially useful in differential diagnosis of COX-deficient Leigh syndrome associated with SURF1 gene mutations, and may limit indications for much more invasive skeletal muscle biopsy.