5 research outputs found
Oxygen consumption in platelets as an adjunct diagnostic method for pediatric mitochondrial disease
Diagnosing mitochondrial disease (MD) is a challenge. In addition to genetic analyses, clinical practice is to perform invasive procedures such as muscle biopsy for biochemical and histochemical analyses. Blood cell respirometry is rapid and noninvasive. Our aim was to explore its possible role in diagnosing MD.MethodsBlood samples were collected from 113 pediatric patients, for whom MD was a differential diagnosis. A respiratory analysis model based on ratios (independent of mitochondrial specific content) was derived from a group of healthy controls and tested on the patients. The diagnostic accuracy of platelet respirometry was evaluated against routine diagnostic investigation.ResultsMD prevalence in the cohort was 16%. A ratio based on the respiratory response to adenosine diphosphate in the presence of complex I substrates had 96% specificity for disease and a positive likelihood ratio of 5.3. None of the individual ratios had sensitivity above 50%, but a combined model had 72% sensitivity.ConclusionNormal findings of platelet respirometry are not able to rule out MD, but pathological results make the diagnosis more likely and could strengthen the clinical decision to perform further invasive analyses. Our results encourage further study into the role of blood respirometry as an adjunct diagnostic tool for MD
Correlation of mitochondrial respiration in platelets, peripheral blood mononuclear cells and muscle fibers
There is a growing interest for the possibility of using peripheral blood cells (including platelets) as markers for mitochondrial function in less accessible tissues. Only a few studies have examined the correlation between respiration in blood and muscle tissue, with small sample sizes and conflicting results.This study investigated the correlation of mitochondrial respiration within and across tissues. Additional analyses were performed to elucidate which blood cell type would be most useful for assessing systemic mitochondrial function.There was a significant but weak within tissue correlation between platelets and peripheral blood mononuclear cells (PBMCs). Neither PBMCs nor platelet respiration correlated significantly with muscle respiration.Muscle fibers from a group of athletes had higher mass-specific respiration, due to higher mitochondrial content than non-athlete controls, but this finding was not replicated in either of the blood cell types. In a group of patients with primary mitochondrial diseases, there were significant differences in blood cell respiration compared to healthy controls, particularly in platelets. Platelet respiration generally correlated better with the citrate synthase activity of each sample, in comparison to PBMCs.In conclusion, this study does not support the theory that blood cells can be used as accurate biomarkers to detect minor alterations in muscle respiration. However, in some instances, pronounced mitochondrial abnormalities might be reflected across tissues and detectable in blood cells, with more promising findings for platelets than PBMCs
Mitochondrial respiratory states and rates: Building blocks of mitochondrial physiology (Part 1)
Supporting co-authors: Bakker BM, Bernardi P, Boetker HE, Borsheim E, Borutaitė V, Bouitbir J, Calbet JA, Calzia E, Chaurasia B, Clementi E, Coker RH, Collin A, Das AM, De Palma C, Dubouchaud H, Durham WJ, Dyrstad SE, Engin AB, Fornaro M, Gan Z, Garlid KD, Garten A, Gourlay CW, Granata C, Haas CB, Haavik J, Haendeler J, Hand SC, Hepple RT, Hickey AJ, Hoel F, Jang DH, Kainulainen H, Khamoui AV, Klingenspor M, Koopman WJH, Kowaltowski AJ, Krajcova A, Lane N, Lenaz G, Malik A, Markova M, Mazat JP, Menze MA, Methner A, Neuzil J, Oliveira MT, Pallotta ML, Parajuli N, Pettersen IKN, Porter C, Pulinilkunnil T, Ropelle ER, Salin K, Sandi C, Sazanov LA, Silber AM, Skolik R, Smenes BT, Soares FAA, Sokolova I, Sonkar VK, Swerdlow RH, Szabo I, Trifunovic A, Thyfault JP, Valentine JM, Vieyra A, Votion DM, Williams C, Zischka HAs the knowledge base and importance of mitochondrial physiology to human health expand, the necessity for harmonizing nomenclature concerning mitochondrial respiratory states and rates has become increasingly apparent. Clarity of concept and consistency of nomenclature are key trademarks of a research field. These trademarks facilitate effective transdisciplinary communication, education, and ultimately further discovery. Peter Mitchell’s chemiosmotic theory establishes the link between vectorial and scalar energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theory and nomenclature for mitochondrial physiology and bioenergetics. Herein, we follow IUPAC guidelines on general terms of physical chemistry, extended by considerations on open systems and irreversible thermodynamics. We align the nomenclature and symbols of classical bioenergetics with a concept-driven constructive terminology to express the meaning of each quantity clearly and consistently. In this position statement, in the frame of COST Action MitoEAGLE, we endeavour to provide a balanced view on mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately support the development of databases of mitochondrial respiratory function in species, tissues, and cells.We thank M. Beno for management assistance. Supported by COST Action CA15203 MitoEAGLE and K-Regio project MitoFit (E.G.).N