TY  - JOUR
A1  - Hocher, Berthold
A1  - Armbruster, Franz Paul
A1  - Stöva, Stanka
A1  - Reichetzeder, Christoph
A1  - Groen, Hans Jürgen
A1  - Lieker, Ina
A1  - Khadzhynov, Dmytro
A1  - Slowinski, Torsten
A1  - Roth, Heinz Jürgen
T1  - Measuring Parathyroid Hormone (PTH) in patients with oxidative stress - do we need a fourth generation Parathyroid Hormone assay?
T2  - PLoS one
N2  - Oxidation of PTH at methionine residues results in loss of biological activity. PTH may be oxidized in patients with renal disease. The aim of this study was to develop an assay considering oxidation of PTH. Oxidized hPTH was analyzed by high resolution nano-liquid chromatography coupled to ESI-FTT tandem mass spectrometry (nanoLC-ESI-FT-MS/MS) directly and after proteolytic cleavage. The oxidized hPTH(1-84) sample shows TIC-peaks at 18-20 min and several mass peaks due to mass shifts caused by oxidations. No significant signal for oxidized hPTH(1-84) species after removal of oxidized PTH molecules by a specific column with monoclonal antibodies (MAB) raised against the oxidized hPTH was detectable. By using this column in samples from 18 patients on dialysis we could demonstrate that measured PTH concentrations were substantially lower when considering oxidized forms of PTH. The relationship between PTH concentrations determined directly and those concentrations measured after removal of the oxidized PTH forms varies substantially. In some patients only 7% of traditionally measured PTH was free of oxidation, whereas in other patients 34% of the traditionally measured PTH was real intact PTH. In conclusion, a huge but not constant proportion of PTH molecules are oxidized in patients requiring dialysis. Since oxidized PTH is biologically inactive, the currently used methods to detect PTH in daily clinical practice may not adequately reflect PTH-related bone and cardiovascular abnormalities in patients on dialysis.
Y1  - 2012
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/35769
SN  - 1932-6203
VL  - 7
IS  - 7
PB  - PLoS
CY  - San Fransisco
ER  -