[Spinal hyperostosis and disorders of retinol metabolism]

Vitamin A or its acid derivatives can be responsible for bony lesions similar to those in ankylosing hyperostosis in animals and in man. We performed a controlled, prospective study on vitamin A metabolism in 23 patients with ankylosing hyperostosis and in 17 normal controls. Beta-carotene serum levels were determined by spectrophotometry, and retinol serum levels by inverse phase high performance liquid chromatography, and retinol binding protein (RBP) by radial immunodiffusion. After eliminating the causes which disturb vitamin A metabolism or RBP, we found a significant increase in retinol (p less than 0.02), in the molar relationship, retinol/RBP (p less than 0.05), without zinc deficiency. The association of diabetes with ankylosing hyperostosis normalizes in a statistically significant manner serum retinol levels (p less than 0.05), but apparently does not modify the increased molar relationship, retinol/RBP. These findings suggest a toxic effect of retinol due to the increased amount of free retinol or by nonspecific transport by proteins other than RBP.