Page 270 - Haematologica Vol. 110 - January 2025

COMMENT
Around 75% of the patients included in our study5 were under hydroxyurea therapy, and all patients from the mito- chondrial respiration experiments received this treatment. Hydroxyurea has recently been shown to promote erythroid differentiation by accelerating maturation processes,13 which may impact the degree of mitochondrial retention into ma- ture red blood cells. To answer this question, a study would be needed to test the degree of mitochondrial retention into mature red blood cells and their functionality before and after hydroxyurea therapy.
In light of the excellent comment by Willis et al.,6 here are some recommendations that should be useful to ensure the best accuracy when measuring mitochondrial respi- ration from red blood cells: i) provide the range of PO2 at which JO2 measurements are conducted; ii) ensure that measurements are conducted at a PO2 being within a linear and almost flat part of the Hb-O2 dissociation curve; iiii) check for potential bias between experimental groups in terms of Hb content or O2 binding kinetics; iv) measure Hb in individual samples to correct JO2 if deemed necessary based on theoretical expectations (e.g., if Hb content is high and variable between samples) or if a difference exists between groups in terms of Hb content.
Naturels et Anthropisés, CNRS UMR 5023, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
Correspondence:
A. STIER - antoine.stier@iphc.cnrs.fr
P. CONNES - philippe.connes@univ-lyon1.fr
https://doi.org/10.3324/haematol.2024.286361
Received: August 5, 2024. Accepted: August 8, 2024. Early view: August 15, 2024.
©2025 Ferrata Storti Foundation Published under a CC BY-NC license
Disclosures
No conflicts of interest to disclose.
Contributions
AS collected and analyzed the data, and wrote the manuscript with input from PC, SE, EN and DR.
Acknowledgments
We are grateful to Willis et al.6 for their excellent commentary leading us to dig deeper in the contribution of Hb-O2 dissociation to respiration rates measured during respirometry experiments with red blood cells.
Funding
This study was supported by the European Framework Horizon 2020 under grant agreement number 860436 (EVIDENCE) and AS was funded by the CNRS.
Data-sharing statement
The data used in this study is publicly available in the Online Supplementary Appendix.
Biol. 2022;225(9):jeb243414.
5. Esperti S, Nader E, Stier A, et al. Increased retention of functional
mitochondria in mature sickle red blood cells is associated with increased sickling tendency, hemolysis and oxidative stress. Haematologica. 2023;108(11):3086-3094.
6. Willis WT, Berry AC, Gladden LB. Does hemoglobin affect measures of mitochondrial respiration in red blood cells? Haematologica. 2024 Aug 1. doi: 10.3324/haematol.2024.286135. [Epub ahead of print]
7. Stier A, Monaghan P, Metcalfe NB. Experimental demonstration of prenatal programming of mitochondrial aerobic metabolism lasting until adulthood. Proc Royal Soc B. 2022;289(1970):20212679.
8. Abdu A, Gómez-Márquez J, Aldrich TK. The oxygen affinity of sickle hemoglobin. Respir Physiol Neurobiol. 2008;161(1):92-94.
Authors
Antoine Stier,1,2 Sofia Esperti,3,4,5 Elie Nader,3,4 Damien Roussel6 and Philippe Connes3,4
1Université de Strasbourg, CNRS, Institut Pluridisciplinaire Hubert Curien, UMR7178, Strasbourg, France; 2Department of Biology, University of Turku, Turku, Finland; 3Laboratoire interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team «Vascular Biology and Red Blood Cell» Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France; 4Laboratoire d’Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France; 5Erytech Pharma, Lyon, France and 6Laboratoire d’Ecologie des Hydrosystèmes
References
1. Stier A, Romestaing C, Schull Q, et al. How to measure mitochondrial function in birds using red blood cells: a case study in the king penguin and perspectives in ecology and evolution. Methods Ecol Evol. 2017;8(10):1172-1182.
2. Braganza A, Annarapu GK, Shiva S. Blood-based bioenergetics: an emerging translational and clinical tool. Mol Aspects Med. 2020;71:100835.
3. Stier A, Bize P, Schull Q, et al. Avian erythrocytes have functional mitochondria, opening novel perspectives for birds as animal models in the study of ageing. Front Zool. 2013;10(1):33.
4. Cossin-Sevrin N, Hsu B-Y, Marciau C, Viblanc VA, Ruuskanen S, Stier A. Effect of prenatal glucocorticoids and thyroid hormones on developmental plasticity of mitochondrial aerobic metabolism, growth and survival: an experimental test in wild great tits. J Exp
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