TY  - JOUR
A1  - Hocher, Berthold
A1  - Oberthür, Dominik
A1  - Slowinski, Torsten
A1  - Querfeld, Uwe
A1  - Schäfer, Franz
A1  - Doyon, Anke
A1  - Tepel, Martin
A1  - Roth, Heinz J.
A1  - Grön, Hans J.
A1  - Reichetzeder, Christoph
A1  - Betzel, Christian
A1  - Armbruster, Franz Paul
T1  - Modeling of Oxidized PTH (oxPTH) and Non-oxidized PTH (n-oxPTH) Receptor Binding and Relationship of Oxidized to Non-Oxidized PTH in Children with Chronic Renal Failure, Adult Patients on Hemodialysis and Kidney Transplant Recipients
JF  - Kidney & blood pressure research : official organ of the Gesellschaft für Nephrologie
N2  - Background: The biological properties of oxidized and non-oxidized PTH are substantially different. Oxidized PTH (oxPTH) loses its PTH receptor-stimulating properties, whereas non-oxidized PTH (n-oxPTH) is a full agonist of the receptor. This was described in more than 20 well published studies in the 1970(s) and 80(s). However, PTH oxidation has been ignored during the development of PTH assays for clinical use so far. Even the nowadays used third generation assay systems do not consider oxidation of PTH. We recently developed an assay to differentiate between oxPTH and n-oxPTH. In the current study we established normal values for this assay system. Furthermore, we compare the ratio of oxPTH to n-oxPTH in different population with chronic renal failure: 620 children with renal failure stage 2-4 of the 4C study, 342 adult patients on dialysis, and 602 kidney transplant recipients. In addition, we performed modeling of the interaction of either oxPTH or n-oxPTH with the PTH receptor using biophysical structure approaches. Results: The children had the highest mean as well as maximum n-oxPTH concentrations as compared to adult patients (both patients on dialysis as well as kidney transplant recipients). The relationship between oxPTH and n-oxPTH of individual patients varied substantially in all three populations with renal impairment. The analysis of n-oxPTH in 89 healthy control subjects revealed that n-oxPTH concentrations in patient with renal failure were higher as compared to healthy adult controls (2.25-fold in children with renal failure, 1.53-fold in adult patients on dialysis, and 1.56-fold in kidney transplant recipients, respectively). Computer assisted biophysical structure modeling demonstrated, however, minor sterical- and/or electrostatic changes in oxPTH and n-oxPTH. This indicated that PTH oxidation may induce refolding of PTH and hence alters PTH-PTH receptor interaction via oxidation induced three-dimensional structure alteration of PTH. Conclusion: A huge proportion of circulating PTH measured by current state-of-the-art assay systems is oxidized and thus not biologically active. The relationship between oxPTH and n-oxPTH of individual patients varied substantially. Non-oxidized PTH concentrations are 1.5 - 2.25 fold higher in patients with renal failure as compared to health controls. Measurements of n-oxPTH may reflect the hormone status more precise. The iPTH measures describes most likely oxidative stress in patients with renal failure rather than the PTH hormone status. This, however, needs to be demonstrated in further clinical studies.
KW  - n-oxPTH
KW  - Chronic Renal Failure
KW  - Kidney Transplantation
KW  - Hemodialysis
KW  - Oxidation
KW  - PTH
KW  - Chronic Renal Failure in Children
Y1  - 2013
U6  - https://doi.org/10.1159/000350149
SN  - 1420-4096
SN  - 1423-0143
VL  - 37
IS  - 4-5
SP  - 240
EP  - 251
PB  - Karger
CY  - Basel
ER  - 
TY  - JOUR
A1  - Tepel, Martin
A1  - Armbruster, Franz Paul
A1  - Groen, Hans Juergen
A1  - Scholze, Alexandra
A1  - Reichetzeder, Christoph
A1  - Roth, Heinz Jürgen
A1  - Hocher, Berthold
T1  - Nonoxidized, biologically active parathyroid hormone determines mortality in hemodialysis patients
JF  - The journal of clinical endocrinology & metabolism
N2  - Background: It was shown that nonoxidized PTH (n-oxPTH) is bioactive, whereas the oxidation of PTH results in a loss of biological activity.
 Methods: In this study we analyzed the association of n-oxPTH on mortality in hemodialysis patients using a recently developed assay system.
 Results: Hemodialysis patients (224 men, 116 women) had a median age of 66 years. One hundred seventy patients (50%) died during the follow-up period of 5 years. Median n-oxPTH levels were higher in survivors (7.2 ng/L) compared with deceased patients (5.0 ng/L; P = .002). Survival analysis showed an increased survival in the highest n-oxPTH tertile compared with the lowest n-oxPTH tertile (chi(2), 14.3; P = 0008). Median survival was 1702 days in the highest n-oxPTH tertile, whereas it was only 453 days in the lowest n-oxPTH tertile. Multivariable-adjusted Cox regression showed that higher age increased odds for death, whereas higher n-oxPTH reduced the odds for death. Another model analyzing a subgroup of patients with intact PTH (iPTH) concentrations at baseline above the upper normal range of the iPTH assay (70 ng/L) revealed that mortality in this subgroup was associated with oxidized PTH but not with n-oxPTH levels.
 Conclusions: The predictive power of n-oxPTH and iPTH on the mortality of hemodialysis patients differs substantially. Measurements of n-oxPTH may reflect the hormone status more precisely. The iPTH-associated mortality is most likely describing oxidative stress-related mortality.
Y1  - 2013
U6  - https://doi.org/10.1210/jc.2013-2139
SN  - 0021-972X
SN  - 1945-7197
VL  - 98
IS  - 12
SP  - 4744
EP  - 4751
PB  - Endocrine Society
CY  - Chevy Chase
ER  - 
TY  - CHAP
A1  - Hocher, Berthold
A1  - Armbruster, Franz Paul
A1  - Scholze, Alexandra
A1  - Marckmann, Peter
A1  - Reichetzeder, Christoph
A1  - Roth, Heinz Jürgen
A1  - Tepel, Martin
T1  - Non-oxidized, biological active parathyroid hormone determines motality in hemodialsysis patients
T2  - Nephrology, dialysis, transplantation
Y1  - 2013
SN  - 0931-0509
VL  - 28
SP  - 33
EP  - 33
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - GEN
A1  - Hocher, Berthold
A1  - Oberthür, Dominik
A1  - Slowinski, Torsten
A1  - Querfeld, Uwe
A1  - Schaefer, Franz
A1  - Doyon, Anke
A1  - Tepel, Martin
A1  - Roth, Heinz J.
A1  - Grön, Hans J.
A1  - Reichetzeder, Christoph
A1  - Betzel, Christian
A1  - Armbruster, Franz Paul
T1  - Modeling of oxidized PTH (oxPTH) and non-oxidized PTH (n-oxPTH) receptor binding and relationship of oxidized to non-oxidized PTH in children with chronic renal failure, adult patients on hemodialysis and kidney transplant recipients
N2  - Background: The biological properties of oxidized and non-oxidized PTH are substantially different. Oxidized PTH (oxPTH) loses its PTH receptor-stimulating properties, whereas non-oxidized PTH (n-oxPTH) is a full agonist of the receptor. This was described in more than 20 well published studies in the 1970(s) and 80(s). However, PTH oxidation has been ignored during the development of PTH assays for clinical use so far. Even the nowadays used third generation assay systems do not consider oxidation of PTH. We recently developed an assay to differentiate between oxPTH and n-oxPTH. In the current study we established normal values for this assay system. Furthermore, we compare the ratio of oxPTH to n-oxPTH in different population with chronic renal failure: 620 children with renal failure stage 2-4 of the 4C study, 342 adult patients on dialysis, and 602 kidney transplant recipients. In addition, we performed modeling of the interaction of either oxPTH or n-oxPTH with the PTH receptor using biophysical structure approaches. Results: The children had the highest mean as well as maximum n-oxPTH concentrations as compared to adult patients (both patients on dialysis as well as kidney transplant recipients). The relationship between oxPTH and n-oxPTH of individual patients varied substantially in all three populations with renal impairment. The analysis of n-oxPTH in 89 healthy control subjects revealed that n-oxPTH concentrations in patient with renal failure were higher as compared to healthy adult controls (2.25-fold in children with renal failure, 1.53-fold in adult patients on dialysis, and 1.56-fold in kidney transplant recipients, respectively). Computer assisted biophysical structure modeling demonstrated, however, minor sterical- and/or electrostatic changes in oxPTH and n-oxPTH. This indicated that PTH oxidation may induce refolding of PTH and hence alters PTH-PTH receptor interaction via oxidation induced three-dimensional structure alteration of PTH. Conclusion: A huge proportion of circulating PTH measured by current state-of-the-art assay systems is oxidized and thus not biologically active. The relationship between oxPTH and n-oxPTH of individual patients varied substantially. Non-oxidized PTH concentrations are 1.5 - 2.25 fold higher in patients with renal failure as compared to health controls. Measurements of n-oxPTH may reflect the hormone status more precise. The iPTH measures describes most likely oxidative stress in patients with renal failure rather than the PTH hormone status. This, however, needs to be demonstrated in further clinical studies.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 343 
KW  - n-oxPTH
KW  - chronic renal failure
KW  - kidney transplantation
KW  - hemodialysis
KW  - oxidation
KW  - PTH
KW  - chronic renal failure in children
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-399980
ER  -