Plasma myostatin measured by a competitive ELISA using a highly specific antiserum

Understanding the (patho)physiology of the negative muscle regulator myostatin (Myo) is important for patients with skeletal muscle disorders or cardiac disease. However, a reliable tool for measuring plasma Myo immunoreactivity is still lacking. Human full-length proMyo was used to raise a polyclonal rabbit antiserum for a competitive Myo ELISA that was validated in patients with decompensated congestive heart failure (CHF) and in control patients (n=20 each). The Myo antiserum detected all subunits of human proMyo. The calibration curve showed an optimal range between 0.3 and 83.3ng/ml (7.5–2100pmol/l), with no cross-reactivity to growth differentiation factor-11, follistatin and follistatin-related gene protein. The inter-assay and intra-assay variances in human serum were ≤15% and ≤10%, respectively; the detection limit was 270pg/ml (6.75pmol/l). The assay showed excellent linearity in human plasma. Plasma NT-proBNP and Myo were significantly elevated in decompensated CHF compared with control patients and decreased significantly upon recompensating therapy. We describe the development of the first ELISA for myostatin immunoreactivity and its validation during recompensating therapy for CHF. This assay will be valuable for investigating neurological and cardiac diseases and states of cachexia, insulin resistance, and obesity. ► Myostatin negatively regulates muscle growth. ► We developed the first ELISA for human myostatin. ► Plasma myostatin was elevated in human heart failure and decreased by therapy. ► Cardiac cachexia may be an important future application of this test.