title: Highly specific detection of myostatin prodomain by an immunoradiometric sandwich assay in serum of healthy individuals and patients.
abstract: BACKGROUND
  Myostatin is a muscle derived factor that functions as a negative regulator of skeletal muscle growth. Induction of myostatin expression was observed in rodent models of muscle wasting and in cachectic patients with cancer or pulmonary disease. Therefore, there is an increasing interest to use serum myostatin as a biomarker.
  
  
  METHODS
  We established an immunoradiometric sandwich assay (IRMA), which uses a commercially available chicken polyclonal, affinity purified antibody directed against human myostatin prodomain. We determined the serum concentrations of myostatin prodomain in 249 healthy individuals as well as 169 patients with heart failure, 53 patients with cancer and 44 patients with chronic pulmonary disease.
  
  
  RESULTS
  The IRMA had a detection limit of 0.7ng/ml, an intraassay imprecision of ≤14.1% and an interassay imprecision of ≤ 18.9%. The specificity of our assay was demonstrated by size exclusion chromatography, detection of myostatin by Western-blotting and a SMAD-dependent transcriptional-reporter assay in the signal-rich serum fractions, as well as lack of interference by unspecific substances like albumin, hemoglobin or lipids. Myostatin prodomain was stable at room temperature and resistant to freeze-thaw cycles. Apparently healthy individuals over the age of 55 had a median myostatin prodomain serum concentration of 3.9ng/ml (25(th)-75(th) percentiles, 2-7ng/ml) and we could not detect increased levels in patients with stable chronic heart failure or cancer related weight loss. In contrast, we found strongly elevated concentrations of myostatin prodomain (median 26.9ng/ml, 25(th)-75(th) percentiles, 7-100ng/ml) in the serum of underweight patients with chronic pulmonary disease.
  
  
  CONCLUSIONS
  We established a highly specific IRMA for the quantification of myostatin prodomain concentration in human serum. Our assay could be useful to study myostatin as a biomarker for example in patients with chronic pulmonary disease, as we detected highly elevated myostatin prodomain serum levels in underweight individuals of this group.
authors.affiliation: Klinik für Kardiologie und Angiologie, Medizinische Hochschule Hannover, Hannover, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Breitbart
authors.forename: Gesine M
authors.initials: GM
authors.lastname: Scharf
authors.forename: David
authors.initials: D
authors.lastname: Duncker
authors.forename: Christian
authors.initials: C
authors.lastname: Widera
authors.forename: Jens
authors.initials: J
authors.lastname: Gottlieb
authors.forename: Arndt
authors.initials: A
authors.lastname: Vogel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Schmidt
authors.forename: Gudrun
authors.initials: G
authors.lastname: Brandes
authors.forename: Hans-Gert
authors.initials: HG
authors.lastname: Heuft
authors.forename: Ralf
authors.initials: R
authors.lastname: Lichtinghagen
authors.forename: Tibor
authors.initials: T
authors.lastname: Kempf
authors.forename: Kai C
authors.initials: KC
authors.lastname: Wollert
authors.forename: Johann
authors.initials: J
authors.lastname: Bauersachs
authors.forename: Joerg
authors.initials: J
authors.lastname: Heineke
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D002908:Chronic Disease; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000097:blood / Q000378:metabolism; D006333:Heart Failure / Q000097:blood / Q000378:metabolism; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods* / Q000592:standards; D008171:Lung Diseases / Q000097:blood / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology; D009133:Muscular Atrophy / Q000097:blood / Q000209:etiology / Q000378:metabolism; D055435:Myostatin / Q000097:blood* / Q000378:metabolism; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D055435:Myostatin