Alma M A Mingels1,2, Eline P M Cardinaels3,2, Natascha J H Broers4,5, Anneke van Sleeuwen3,2, Alexander S Streng3,2, Marja P van Dieijen-Visser3,2, Jeroen P Kooman4,5, Otto Bekers3,2. 1. Department of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center; alma.mingels@mumc.nl. 2. Cardiovascular Research Institute Maastricht (CARIM), Maastricht University. 3. Department of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center. 4. Department of Internal Medicine, Division of Nephrology, Maastricht University Medical Center; and. 5. School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, the Netherlands.
Abstract
BACKGROUND: We have found previously that in acute myocardial infarction (AMI), cardiac troponin T (cTnT) is degraded in a time-dependent pattern. We investigated whether cTnT forms differed in patients with chronic cTnT increases, as seen with renal dysfunction, from those in the acute phase of myocardial infarction. METHODS: We separated cTnT forms by gel filtration chromatography (GFC) in end-stage renal disease (ESRD) patients: prehemodialysis (pre-HD) and post-HD (n = 10) and 2 months follow-up (n = 6). Purified (cTnT) standards, quality control materials of the clinical cTnT immunoassay (Roche), and AMI patients' sera also were analyzed. Immunoprecipitation and Western blotting were performed with the original cTnT antibodies from the clinical assay and antibodies against the N- and C-terminal end of cTnT. RESULTS: GFC analysis revealed the retention of purified cTnT at 27.5 mL, identical to that for cTnT in quality controls. For all ESRD patients, one cTnT peak was found at 45 mL, pre- and post-HD, and stable over time. Western blotting illustrated that this peak corresponded to cTnT fragments <18 kDa missing the N- and C-terminal ends. AMI patients' sera revealed cTnT peaks at 27.5 and 45 mL, respectively, corresponding to N-terminal truncated cTnT of 29 kDa and N- and C-terminal truncated fragments of <18 kDa, respectively. CONCLUSIONS: We found that cTnT forms in ESRD patients are small (<18 kDa) and different from forms seen in AMI patients. These insights may prove useful for development of a more specific cTnT immunoassay, especially for the acute and diagnostic phase of myocardial infarction.
BACKGROUND: We have found previously that in acute myocardial infarction (AMI), cardiac troponin T (cTnT) is degraded in a time-dependent pattern. We investigated whether cTnT forms differed in patients with chronic cTnT increases, as seen with renal dysfunction, from those in the acute phase of myocardial infarction. METHODS: We separated cTnT forms by gel filtration chromatography (GFC) in end-stage renal disease (ESRD) patients: prehemodialysis (pre-HD) and post-HD (n = 10) and 2 months follow-up (n = 6). Purified (cTnT) standards, quality control materials of the clinical cTnT immunoassay (Roche), and AMI patients' sera also were analyzed. Immunoprecipitation and Western blotting were performed with the original cTnT antibodies from the clinical assay and antibodies against the N- and C-terminal end of cTnT. RESULTS: GFC analysis revealed the retention of purified cTnT at 27.5 mL, identical to that for cTnT in quality controls. For all ESRDpatients, one cTnT peak was found at 45 mL, pre- and post-HD, and stable over time. Western blotting illustrated that this peak corresponded to cTnT fragments <18 kDa missing the N- and C-terminal ends. AMI patients' sera revealed cTnT peaks at 27.5 and 45 mL, respectively, corresponding to N-terminal truncated cTnT of 29 kDa and N- and C-terminal truncated fragments of <18 kDa, respectively. CONCLUSIONS: We found that cTnT forms in ESRDpatients are small (<18 kDa) and different from forms seen in AMI patients. These insights may prove useful for development of a more specific cTnT immunoassay, especially for the acute and diagnostic phase of myocardial infarction.
Authors: Douwe de Boer; Alexander S Streng; William P T M van Doorn; Wim H M Vroemen; Otto Bekers; Will K W H Wodzig; Alma M A Mingels Journal: Adv Exp Med Biol Date: 2021 Impact factor: 2.622
Authors: Sander A J Damen; Wim H M Vroemen; Marc A Brouwer; Stephanie T P Mezger; Harry Suryapranata; Niels van Royen; Otto Bekers; Steven J R Meex; Will K W H Wodzig; Freek W A Verheugt; Douwe de Boer; G Etienne Cramer; Alma M A Mingels Journal: J Am Heart Assoc Date: 2019-07-04 Impact factor: 5.501
Authors: Vincent L Aengevaeren; Aaron L Baggish; Eugene H Chung; Keith George; Øyunn Kleiven; Alma M A Mingels; Stein Ørn; Rob E Shave; Paul D Thompson; Thijs M H Eijsvogels Journal: Circulation Date: 2021-12-13 Impact factor: 29.690