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Updated: May 5, 2026
Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes
Published on: September 18, 2017
Protein restriction after weaning modifies the calcium kinetics and induces cardiomyocyte contractile dysfunction in
Arlete R Penitente1, Rômulo D Novaes, Deoclécio A Chianca
1Department of General Biology, Federal University of Viçosa, Viçosa, Brazil.
Insights
Short-term protein restriction (PR) in young rats impairs cardiomyocyte function and alters heart structure. This dietary change affects calcium handling and cardiac remodeling, potentially impacting cardiovascular health.
Area of Science:
- Cardiovascular Physiology
- Nutritional Science
- Cell Biology
Background:
- Protein restriction (PR) is linked to cardiovascular diseases.
- Understanding the impact of early-life nutrition on cardiac health is crucial.
Purpose of the Study:
- To investigate the effects of short-term protein restriction after weaning on single ventricular cardiomyocyte contractile function.
- To analyze structural and functional changes in the rat heart following PR.
Main Methods:
- Male Fischer rats (28 days old) were divided into control (15% protein) and protein-restricted (6% protein) groups for 35 days.
- Evaluated biometric parameters, heart weight, collagen content, and cardiomyocyte structure (length, width, volume, sarcomere length).
- Assessed cardiomyocyte contractile function and intracellular calcium transients in isolated left ventricular (LV) cardiomyocytes.
Main Results:
- Protein-restricted rats showed lower body and LV weight, increased LVW/BW ratio, and higher collagen proportion.
- Reduced cardiomyocyte size and sarcomere length were observed in the PR group.
- Impaired cardiomyocyte contractility (reduced shortening amplitude, slower peak, longer relaxation) and altered calcium transients (lower peak, slower decay) were found.
Conclusions:
- Short-term protein restriction post-weaning induces significant myocardial structural remodeling in rats.
- Contractile dysfunction in cardiomyocytes is associated with altered intracellular calcium kinetics.
- These changes suggest potential long-term cardiovascular implications of early-life nutritional deficits.
Abstract:
Protein restriction (PR) is associated with cardiovascular diseases. The purpose of this study was to investigate the effects on single ventricular cardiomyocyte contractile function of a short-term PR after weaning. Male Fischer rats that were 28 days old were randomly divided into a control group (CG, n = 16) and a protein-restricted group (PRG, n = 16). After weaning, CG and PRG animals received isocaloric diets containing 15 and 6% protein, respectively, for 35 days. Biometric parameters were then measured, and the hearts were removed for the analysis of contractile function and calcium transient in isolated cardiomyocytes of the left ventricule (LV), and the quantification of calcium and collagen fibers in LV myocardium. PRG animals had lower body weight (BW) and LV weight (LVW), an increased LVW to BW ratio and a higher proportion of collagen fibers than CG animals. PRG animals exhibited reduced tissue levels of calcium, reduced the length, width and volume of cardiomyocytes and their sarcomere length compared to CG animals. Cardiomyocytes from PRG animals had a lower amplitude of shortening, a slower time to the peak of shortening and a longer time to half-relaxation than those from the CG. Cardiomyocytes from PRG animals also presented a lower peak of calcium transient and a longer calcium transient decay time than CG animals. Taken together, the results indicate that short-term PR after weaning induces a marked structural remodeling of the myocardium parenchyma and stroma that coexists with contractile dysfunctions in single LV cardiomyocytes of rats, which is probably associated with pathological changes of the intracellular calcium kinetics, rather than inadequate available amounts of this mineral in cardiac tissue.
