Effect of caloric restriction on phosphate metabolism and uremic vascular calcification.

Abstract

Caloric restriction (CR) is known to have multiple beneficial effects on health and longevity. To study the effect of CR on phosphorus metabolism and vascular calcification (VC), rats were fed normal or restricted calories (67% of normal). The phosphorus content of the diets was adjusted to provide equal phosphorus intake independent of the calories ingested. After 50 days of CR, rats had negative phosphorus balance, lower plasma phosphorus, glucose, triglycerides, and leptin, and higher adiponectin than rats fed normal calories. Uremia was induced by 5/6 nephrectomy (Nx). After Nx, rats were treated with calcitriol (80 ng/kg ip every other day) and high-phosphorus diets (1.2% and 1.8%). No differences in aortic calcium content were observed between rats that ate normal or restricted calories before Nx in either rats that received 1.2% phosphorus (11.5 ± 1.7 vs. 10.9 ± 2.1 mg/g tissue) or in rats that received 1.8% phosphorus (12.5 ± 2.3 vs. 12.0 ± 2.9 mg/g of tissue). However, mortality was significantly increased in rats subjected to CR before Nx in both the 1.2% phosphorus groups (75% vs. 25%, P = 0.019) and 1.8% phosphorus groups (100% vs. 45%, P < 0.001). After calcitriol administration was stopped and phosphorus intake was normalized, VC regressed rapidly, but no significant differences in aortic calcium were detected between rats that ate normal or restricted calories during the regression phase (5.7 ± 2.7 and 5.2 ± 1.5 mg/g tissue). In conclusion, CR did not prevent or ameliorate VC and increased mortality in uremic rats.

• Authors: Angela Vidal, Rafael Rios, Carmen Pineda, Ignacio Lopez, Mariano Rodriguez, Escolastico Aguilera-Tejero, Ana I Raya
• Journal: American journal of physiology. Renal physiology (Am J Physiol Renal Physiol) Vol. 318 Issue 5 Pg. F1188-F1198 (05 01 2020) ISSN: 1522-1466 [Electronic] United States
• PMID: 32249611 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Fgf23 protein, rat
• Phosphorus, Dietary
• Fibroblast Growth Factors
• Glucuronidase
• Klotho Proteins
• Calcitriol

Topics

• Animals
• Aorta (metabolism, pathology)
• Aortic Diseases (etiology, metabolism, pathology, prevention & control)
• Calcitriol
• Caloric Restriction
• Disease Models, Animal
• Disease Progression
• Energy Metabolism
• Female
• Fibroblast Growth Factors (blood)
• Glucuronidase (metabolism)
• Kidney (metabolism, pathology)
• Klotho Proteins
• Nephrectomy
• Phosphorus, Dietary (metabolism)
• Rats, Wistar
• Time Factors
• Uremia (diet therapy, etiology, metabolism)
• Vascular Calcification (etiology, metabolism, pathology, prevention & control)