What is the clinical evidence from this study?

Population: minK gene expression / cardiac conduction system. Intervention: minK gene deletion (minK -/-) vs. Wild-type mice (+/+). Primary outcome: IKs and IKr currents, ECG parameters, and beta-galactosidase expression.

What question did this study set out to answer?

To determine the developmental expression pattern and electrophysiological function of the minK gene in the mouse heart.

February 5, 1999Circulation Research

Replacement by Homologous Recombination of the minK Gene With lacZ Reveals Restriction of minK Expression to the Mouse Cardiac Conduction System

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Key result

Deletion of the minK gene in mice resulted in absent IKs and reduced IKr currents, but no changes in ECGs, with minK expression restricted to the cardiac conduction system.

Why the study?

Does minK gene deficiency alter cardiac delayed rectifier currents and ECG characteristics in mice?

Population

Wild-type and minK-deficient (-/-) mice (neonatal and adult stages)

Comparison

minK gene deficiency vs Wild-type (+/+) mice

Design

Preclinical

Authors

SKSabina KupershmidtApple (Israel)TYTao YangTang Du Hospital MAMark E. AndersonUniversity of Central Florida

Discussion

Member takes

Implication

minK deletion alters repolarizing currents without ECG effects in mice; leaves open species-specific roles in human conduction system electrophysiology.

Key Points

To determine the developmental expression pattern and electrophysiological function of the minK gene in the mouse heart.
Generated minK-deficient mice by replacing the minK coding region with the bacterial lacZ reporter gene via homologous recombination.
Recorded delayed rectifier currents (IKr and IKs) in isolated neonatal myocytes and evaluated surface ECGs in adult and neonatal mice at baseline and following isoproterenol stimulation.
Mapped spatial and temporal minK expression using beta-galactosidase staining in embryonic day 11 and postnatal hearts.
In minK (-/-) myocytes, IKs was completely absent, while IKr was significantly reduced with slowed deactivation kinetics.
Surface ECG parameters showed no significant differences between wild-type and minK-null mice at neonatal or adult stages, including during isoproterenol challenge.
Beta-galactosidase expression was strictly confined to the sinus-node region, caudal atrial septum, and proximal conduction system postnatally, with restricted expression emerging as early as embryonic day 11.

Structured PICO

Does minK gene deficiency alter cardiac delayed rectifier currents and ECG characteristics in mice?

Population

Wild-type and minK-deficient (-/-) mice (neonatal and adult stages)

Intervention

minK gene deficiency (replacement of minK coding region with bacterial lacZ gene)

Comparator

Wild-type (+/+) mice

Outcome

Cardiac delayed rectifier currents (IKr and IKs), ECG characteristics, and beta-galactosidase expression patternssurrogate

The minK gene modulates IKs and IKr currents in mice, and its expression is highly restricted to the cardiac conduction system, suggesting species-specific roles in cardiac electrophysiology.

Cite This Study

Kupershmidt et al. (1999) studied minK gene expression / cardiac conduction system. minK gene deletion (minK -/-) vs. Wild-type mice (+/+) was evaluated on IKs and IKr currents, ECG parameters, and beta-galactosidase expression. Deletion of the minK gene in mice resulted in absent IKs and reduced IKr currents, but no changes in ECGs, with minK expression restricted to the cardiac conduction system.

synapsesocial.com/papers/6a161081dca1af9bedbf8cf1 https://doi.org/10.1161/01.res.84.2.146

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Implication

minK deletion alters repolarizing currents without ECG effects in mice; leaves open species-specific roles in human conduction system electrophysiology.