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Updated: Jul 23, 2026
Histological Quantification of Chronic Myocardial Infarct in Rats
Published on: December 11, 2016
Reduced capillary density in the myocardium of uremic rats--a stereological study
Insights
Experimental uremia in rats leads to cardiac hypertrophy without a corresponding increase in capillaries. This study reveals a significant decrease in capillary length density in uremic hearts, impacting cardiac function.
Area of Science:
- Cardiovascular Physiology
- Renal Medicine
- Stereology
Background:
- Uremia, a complication of chronic kidney disease, affects multiple organ systems.
- Cardiac hypertrophy is a commoncomorbidity in uremic patients.
- The microvascular adaptations in the uremic heart are not fully understood.
Purpose of the Study:
- To investigate the changes in myocardial capillary structure in a rat model of chronic uremia.
- To determine if cardiac hypertrophy in uremia is associated with increased capillary supply.
Main Methods:
- Stereological analysis of perfusion-fixed rat hearts.
- Comparison between subtotally nephrectomized (uremic) rats and sham-operated controls.
- Quantification of capillary length density, surface density, and volume density.
Main Results:
- Uremic rats exhibited higher systolic blood pressure and left ventricular weight/body weight ratio compared to controls.
- A significant decrease (P < 0.001) in capillary length density was observed in uremic rat hearts.
- Reduced capillary lumen surface and volume densities were also noted in uremic hearts.
Conclusions:
- Experimental uremia induces cardiac hypertrophy not matched by a proportional increase in myocardial capillaries.
- The reduced capillary network in uremia may impair oxygen and nutrient delivery to the hypertrophied heart.
- These findings highlight potential microvascular dysfunction contributing to cardiovascular complications in uremia.
Abstract:
Using stereological techniques capillaries, interstitium and myocardial fibers were analyzed in perfusion-fixed hearts of subtotally nephrectomized male Sprague-Dawley rats with uremia of 14 months duration (or their sham-operated controls). Uremic rats had higher systolic blood pressure (140 +/- 20.3 mm Hg vs. 119 +/- 6.61 mm Hg) and left ventricular weight/body weight ratio (3.37 +/- 0.09 mg/kg vs. 2.01 +/- 0.12 mg/kg) than controls, and had slight anemia (Hct 35.0 +/- 3.16% vs. 40.4 +/- 3.3%). Length density (Lv) of capillaries, that is, capillary length per unit myocardial volume, was significantly (P < 0.001) decreased in uremia (2485 +/- 264 mm/mm3 vs. 3329 +/- 194 mm/mm3) versus controls. In parallel, surface density and volume density of the capillary lumina were also reduced (7.95 +/- 1.69 cm3/cm3 vs. 11.4 +/- 1.8 cm3/cm3) in the uremic rats. We conclude that in experimental uremia, cardiac hypertrophy is not accompanied by a commensurate increase in capillaries.
