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MITOCIRCLE. WP 2.2: Defining the standard in biochemical investigation in patients with mitochondrial disease. Maastricht L. van den Heuvel. Nijmegen Center for Mitochondrial Disorders. International Center for Clinical Care, Diagnostics and Research
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MITOCIRCLE • WP 2.2: Defining the standard in biochemical investigation in patients with mitochondrial disease. Maastricht L. van den Heuvel
Nijmegen Center for Mitochondrial Disorders International Center for Clinical Care, Diagnostics and Research of Patients with disturbed Mitochondrial Energy Metabolism DIAGNOSTICS PATIENT CARE RESEARCH
OXIDATIVE PHOSPHORYLATION DISORDERS - progressive - multi-systemic - no therapy - often fatal
OXIDATIVE PHOSPHORYLATION DISORDERS - What is the defect? - What is the prognosis? • Is any therapy available? • How about counseling and prenatal dianosis?
I • The corner stone for diagnostics is the biochemical investigation of a fresh muscle biopsy. INTACT MITOCHONDRIA
Assays in a fresh muscle biopsy (1): • Substrate oxidation rates: pyruvate, succinate and malate • ATP production rate from pyruvate and succinate. • Single enzymes.
Assays in fresh muscle biopsy (2): • NADH:Q1 oxidoreductase (complex I). • Succinate Dehydrogenase (Complex II). • Decylubiquinol: Cyt C Oxidoreductase (Complex III). • Cytochrome C Oxidase (Complex IV). • ATPsynthase (Complex V). • Pyruvate Dehydrogenase complex • Citrate synthase (CS).
Studies in fibroblast: • Confirmation of defect in muscle sample. • Prenatal diagnosis. • Research purposes. • Establish origin of the genetic defect.
mitochondrial donor denucleation rho 0 mitochondrial donor mix and fuse hybrid transmitochondrial recipient rho 0 Rho zero test
MITOCIRCLE • WP 2.2: Defining the standard in biochemical investigation in patients with mitochondrial disease.
Objectives: • Harmonization and validation of protocols for enzyme diagnostics of mitochondrial disorders. • Defining standards for diagnostic tests. • Establishment of reference centres for enzyme diagnostics of mitochondrial disorders. • Performing quality control for tests applied in diagnostics of mitochondrial disorders.
Description of work: • The collection of patient material with established isolated or combined RC enzyme deficiencies. • Establishment of guidelines, organization and meeting of the diagnostic centres involved. • The validation of assays. • Preparation of golden (home made) standards in diagnostic tests for internal quality control. • Organization of external quality control.
Deliverables: • Standardization of the biochemical protocols for the rational diagnostics of mitochondrial disorders. • Method validation to ensure reliable high quality data from diagnostic analyses. • An external quality control system to achieve inter-laboratory comparability. • The re-classification of mitochondrial disorders associated with deficiencies of RC enzymes.
Discussion(1): • 1.)Which tissue will be used for bio-chemical investigation? • - Fresh muscle biopsy • - Frozen muscle biopsy • - Fibroblasts • 2.)Which protocols are used in the different diagnostic centres? • 3.) Which validation has been performed?
Discussion(2): • 4.) Which assays are performed for the ideal biochemical investigation to establish mitochondrial disorders? • - CI, CII, CIII, CIV, CV, PDHc and SCC • - What is the reference? CS, COX, protein, collagen? • 5.)Establishment of uniform biochemical assays. • 6.)Preparation of golden standards. • 7.)Organization of an external quality control.
Acknowledgements NCMD, Nijmegen Cristina Ugalde Marieke Coenen Jeanette Pots Richard Huijbens Rolf Janssen Sandy Budde Rutger Vogel Roel Smeets Edwin van Kaauwen Jan Smeitink Leo Nijtmans Bert van den Heuvel NCMLS, Nijmegen Sjoerd Verkaart Werner Koopman Peter Willems University Oulu, Finland Reetta Mehtala Johanna Uusimaa Kari Majamaa