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Study · In vitro (cells) · rabbit · 2024

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Role of Mitochondrial ROS for Calcium Alternans in Atrial Myocytes.

Oropeza-Almazán Y, Blatter LA

Biomolecules24 Jan 2024Cited by 6 (Europe PMC)

PMID38397381 (opens in a new tab)PMCIDPMC10887423 (opens in a new tab)DOI10.3390/biom14020144 (opens in a new tab)PepBankPUB-38397381
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Summary

Atrial calcium transient (CaT) alternans is defined as beat-to-beat alternations in CaT amplitude and is causally linked to atrial fibrillation (AF). Mitochondria play a significant role in cardiac excitation-contraction coupling and Ca signaling through redox environment regulation. In isolated rabbit atrial myocytes, ROS production is enhanced during CaT alternans, measured by fluorescence microscopy. Exogenous ROS (tert-butyl hydroperoxide) enhanced CaT alternans, whereas ROS scavengers (dithiothreitol, MnTBAP, quercetin, tempol) alleviated CaT alternans. While the inhibition of cellular NADPH oxidases had no effect on CaT alternans, interference with mitochondrial ROS (ROSm) production had profound effects: (1) the superoxide dismutase mimetic MitoTempo diminished CaT alternans and shifted the pacing threshold to higher frequencies; (2) the inhibition of cyt c peroxidase by SS-31, and inhibitors of ROSm production by complexes of the electron transport chain S1QEL1.1 and S3QEL2, decreased the severity of CaT alternans; however (3) the impairment of mitochondrial antioxidant defense by the inhibition of nicotinamide nucleotide transhydrogenase with NBD-Cl and thioredoxin reductase-2 with auranofin enhanced CaT alternans. Our results suggest that intact mitochondrial antioxidant defense provides crucial protection against pro-arrhythmic CaT alternans. Thus, modulating the mitochondrial redox state represents a potential therapeutic approach for alternans-associated arrhythmias, including AF.
CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study1

1 result from studies that gave the peptide. No result from this study comes from people.

  1. 01LabIn vitro (cells)Mechanism

    In isolated rabbit atrial myocytes, inhibition of cytochrome c peroxidase by SS‑31 decreased the severity of calcium transient alternans.

    In plain wordsIn lab tests on rabbit heart cells, SS‑31 reduced the severity of irregular calcium signals linked to atrial fibrillation.

    Peptide
    Elamipretide (SS-31)
    Outcome
    DecreaseSeverity of atrial calcium transient alternans
    Study

    rabbitn: not reported in source

    Isolated rabbit atrial myocytes
    Outcome group
    Heart function · Cardiovascular
    Studied dose
    Dose not stated

    Source sentences

    Summary
    (2) the inhibition of cyt c peroxidase by SS-31, and inhibitors of ROSm production by complexes of the electron transport chain S1QEL1.1 and S3QEL2, decreased the severity of CaT alternans
    1 context sentence
    Summary · context
    In isolated rabbit atrial myocytes, ROS production is enhanced during CaT alternans, measured by fluorescence microscopy.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    10 Oct 2026, 08:19 UTC

    Study results updated

  2. Version 1

    9 Oct 2026, 02:47 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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