Cardiac structure and function in vitamin B-12-deprived rats

Area of Science:

• Biochemistry
• Cardiology
• Nutritional Science

Background:

• Vitamin B-12 is crucial for cellular metabolism.
• Deficiency can lead to neurological and hematological issues.
• Its specific impact on cardiac structure and function requires further elucidation.

Purpose of the Study:

• To investigate the effects of long-term vitamin B-12 deprivation on rat heart histology.
• To examine alterations in cardiac linoleic acid oxidation.
• To identify metabolic defects in B-12 deficient rat hearts.

Main Methods:

• Rats were fed vitamin B-12-deficient diets for up to 16 months.
• Urinary methylmalonic acid levels monitored B-12 deficiency.
• Histological and electron microscopy analyses of heart tissue.
• Isolated heart perfusion studies with labeled propionic acid and linoleic acid.

Main Results:

• Vitamin B-12 deficiency led to extensive cardiac fibrosis and enlarged, distorted mitochondria.
• Hearts from deficient rats showed significantly reduced uptake and oxidation of propionic acid, with methylmalonate accumulation.
• Linoleic acid extraction was unaffected, but its oxidation was markedly increased.
• Reduced succinate levels were observed in perfusion media from deficient hearts.

Conclusions:

• Prolonged vitamin B-12 deficiency severely impacts cardiac structure and metabolism in rats.
• A metabolic block in propionic acid processing contributes to cardiac dysfunction.
• Altered fatty acid oxidation pathways may represent a compensatory mechanism or contribute to pathology.