August 1, 1988Open Access

Synthesis of stress proteins in rat cardiac myocytes 2-4 days after imposition of hemodynamic overload.

Q: What is the clinical evidence from this study?

Study design: Other. Population: Hemodynamic overload (cardiac hypertrophy). Intervention: Hemodynamic overload (aortic stenosis or aortic insufficiency) vs. Sham-operated controls. Primary outcome: Expression of stress proteins (HSP 70, HSP 68, HSP 58) in cardiac myocytes.

CDClaude DelcayreInserm JSJane‐Lise SamuelUniversité Paris Cité FMF. MarotteInserm

Key Result

Hemodynamic overload induced by aortic stenosis or insufficiency in rats led to an early and transient expression of three major stress proteins (HSP 70, HSP 68, and HSP 58) in cardiac myocytes.

Structured PICO

Population

Male Wistar rats subjected to aortic banding or aortic insufficiency to induce compensatory cardiac hypertrophy, evaluated 2 to 21 days post-surgery.

Intervention

Hemodynamic overload (pressure or volume overload) for up to 2 weeks

Comparator

Controls and sham-operated animals

Outcome

Expression of stress proteins (HSP 70, HSP 68, and HSP 58) and putative ribosomal proteinssurrogate

Hemodynamic overload induces early and transient expression of heat shock proteins in rat cardiac myocytes, suggesting a protective mechanism during early adaptation to overload.

Limitations

The measure of the degree of cardiac hypertrophy might be criticized since the whole heart was weighed after a rather rudimentary dissection.
The sensitivity of the immunoblot method does not allow a quantitative evaluation of the relative accumulation of the protein.

Abstract

Isolated adult myocytes incubated with 35Smethionine were used to study the expression of proteins in the rat heart during the first 2 wk after either pressure or volume overload. In both models an early (2-4 d) and transient expression of three major stress proteins (heat shock protein HSP HSP 70, HSP 68, and HSP 58) was observed together with an increased synthesis of putative ribosomal proteins. Only traces of 35S-labeled HSPs were detected in controls and sham-operated animals. The three stress proteins were identified by their migration in two-dimensional gels, by comigration with HSPs, which had been induced in myocytes by incubation at 41 degrees C and immunoblot analysis using antisera directed against the 70-kD protein. Immunohistochemical staining of HSP 70 in rod-shaped myocytes and detection by immunoblot showed that HSP 70 was equally present and distributed in both sham-operated and overloaded hearts, and provided no evidence for a subpopulation of myocytes acutely involved in the increased expression of HSP 70. It is suggested that the transient expression of HSPs that occurs during the early adaptation of the myocardial cells to overload could confer some degree of protection to the actively growing myocytes.

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Cite This Study

Delcayre et al. (Mon,) conducted a other in Hemodynamic overload (cardiac hypertrophy). Hemodynamic overload (aortic stenosis or aortic insufficiency) vs. Sham-operated controls was evaluated on Expression of stress proteins (HSP 70, HSP 68, HSP 58) in cardiac myocytes. Hemodynamic overload induced by aortic stenosis or insufficiency in rats led to an early and transient expression of three major stress proteins (HSP 70, HSP 68, and HSP 58) in cardiac myocytes.

synapsesocial.com/papers/6a6542ef1b122b07e7b2e331 https://doi.org/https://doi.org/10.1172/jci113619