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Leo 2023 ESCI Prague

From Bioblast
Leo Elettra
Leo E, Zdrazilova L, Garcia-Souza LF, Åsander-Frostner E, Elmér E, Gnaiger E (2023) High-resolution respirometry is comparable in 0.5 mL and 2.0 mL chamber volumes: studies with platelets, permeabilized fibroblasts, and isolated mitochondria. 57th Annual Scientific Meeting of the European Society for Clinical Investigation.

Link: 57th Annual Scientific Meeting of the European Society for Clinical Investigation

Leo Elettra, Zdrazilova Lucie, Garcia-Souza Luiz F, Aasander-Frostner Eleonor, Elmer Eskil, Gnaiger Erich (2023)

Event: ESCI 2023 Prague CZ

The volume of the experimental chamber is a fundamental feature in the design of respirometric instruments applied in mitochondrial and cell physiology. Small volumes are considered to minimize the amount of tissue or cell count required, but increasing problems are encountered of O₂ back diffusion, homogenous stirring, and scatter in small-volume wells [1].

We evaluated instrumental performance and respirometric results obtained in parallel experiments with high-resolution respirometry using experimental chamber volumes of 2.0 mL and 0.5 mL. Instrumental background tests performed revealed the expected volume-dependent differences. Human platelets, human permeabilized fibroblasts, and mouse cardiac isolated mitochondria were studied by substrate-uncoupler-inhibitor titration (SUIT) protocols and the correlation between the two chambers was calculated by inverted regression analysis [1].

Close to 4-fold lower amounts of sample were required in 0.5 mL compared to 2.0 mL chambers. In all biological models, oxygen fluxes in the two chambers were highly correlated, with r²=0.99 in platelets; 0.96 and 0.95 in fibroblasts applying two SUIT protocols; and 0.99 in cardiac mitochondria. The general offset from identity was less than 10 % at high fluxes and negligible at very low ones.

In studies with cells and isolated mitochondria, application of the 0.5 mL module is advantageous for reducing the amount of sample, with identical results obtained in the 2 mL chamber. A wet mass <0.5 mg of permeabilized fibers suitable for the small-volume chamber, however, is difficult to be determined accurately. Application of the 0.5 mL chamber under hyperoxia or deep hypoxia remains to be evaluated.


Bioblast editor: Plangger M


Affiliations

Leo E1, Zdrazilova L1, 2, Garcia-Souza LF1, Åsander-Frostner E3, Elmér E3, Gnaiger E1
  1. Oroboros Instruments, Innsbruck, Austria
  2. Department of Pediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General Hospital in Prague, Czechia
  3. Mitochondrial Medicine, Lund University, Lund, Sweden; Abliva AB, Lund, Sweden

References

  1. Zdrazilova L, Hansikova H, Gnaiger E (2022) Comparable respiratory activity in attached and suspended human fibroblasts. PLoS ONE 17:e0264496. https://doi.org/10.1371/journal.pone.0264496

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