What question did this study set out to answer?

To assess whether IgG fractions containing anti-Ro/SSA antibodies induce conduction abnormalities and to identify the underlying cellular electrophysiological mechanisms in rabbit hearts.

February 1, 1994Journal of Clinical InvestigationOpen Access

Cellular mechanism of the conduction abnormalities induced by serum from anti-Ro/SSA-positive patients in rabbit hearts.

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Population

Langendorff preparations of adult rabbit hearts and ventricular myocytes isolated from young rabbit hearts…

Comparison

Perfusion/superfusion with Tyrode's solution… vs Perfusion/superfusion with Tyrode's solution…

Design

Preclinical

Authors

SGSolange Cristina GarcíaUniversidade Federal do Rio Grande do Sul JNJosé NascimentoUniversidade Federal de Pernambuco EBEloísa BonfáUniversidade de São Paulo

Discussion

Member takes

Implication

May explain anti-Ro/SSA-mediated congenital heart block; leaves open human translation and targeted interventions.

Key Points

To assess whether IgG fractions containing anti-Ro/SSA antibodies induce conduction abnormalities and to identify the underlying cellular electrophysiological mechanisms in rabbit hearts.
Perfused isolated adult rabbit hearts in Langendorff preparations with Tyrode's solution containing 0.3 mg/ml IgG from patients positive for anti-Ro/SSA (nine sera), anti-RNP (five sera), or normal donors (five sera).
Applied whole-cell patch-clamp electrophysiology to isolated young rabbit ventricular myocytes to measure slow inward currents, resting potentials, and action potentials following antibody perfusion.
Perfusion with anti-Ro/SSA IgG induced complete heart block in 33.3% of adult rabbit hearts and slowed heart rate by 17.1% in the rest, whereas anti-RNP and normal IgG decreased heart rate by 12.9% and 3.3% without producing heart block.
In isolated ventricular myocytes, anti-Ro/SSA IgG caused a mean reduction in peak slow inward current of 31.6%, compared to a 4.4% reduction with anti-RNP IgG and a 3.3% increase with normal IgG.
Resting potential and action potential amplitudes were unaffected by any tested IgG fraction, and IgG-free fractions from anti-Ro/SSA sera did not alter peak slow inward currents.

Structured PICO

Population

Langendorff preparations of adult rabbit hearts and ventricular myocytes isolated from young rabbit hearts. Sera obtained from SLE patients (1 anti-Ro/SSA- and anti-La/SSB-positive, 10 anti-Ro/SSA-positive, 8 anti-RNP-positive) and 9 normal donors.

Intervention

Perfusion/superfusion with Tyrode's solution containing 0.3 mg/ml of IgG-enriched fractions from anti-Ro/SSA- or anti-Ro/La-positive sera.

Comparator

Perfusion/superfusion with Tyrode's solution containing 0.3 mg/ml of IgG fractions from anti-RNP-positive sera, normal donors, or IgG-depleted fractions.

Outcome

Occurrence of heart block and changes in heart rate in whole hearts; changes in peak slow inward current (Isi) in isolated myocytes.surrogate

Anti-Ro/SSA antibodies from lupus patients can directly induce cardiac conduction disorders by blocking L-type calcium channels, providing a cellular mechanism for congenital heart block in neonatal lupus.

Cite This Study

García et al. (1994) studied this question.

synapsesocial.com/papers/6a789b014fe2e6ffd8ed89b2 https://doi.org/10.1172/jci117025

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Cellular mechanism of the conduction abnormalities induced by serum from anti-Ro/SSA-positive patients in rabbit hearts.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Cellular mechanism of the conduction abnormalities induced by serum from anti-Ro/SSA-positive patients in rabbit hearts.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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