[Small-nodular liver cirrhosis with marked portal hypertension due to vitamin A intoxication resulting from psoriasis treatment (author's transl)]

Vitamin A abuse: development of cirrhosis despite cessation of vitamin A. A six-year clinical and histopathologic follow-up

We report the case of a 35-year-old man who contracted vitamin A-induced liver cirrhosis. Five years before, he had been investigated for vitamin A-induced non-cirrhotic portal hypertension. In this case, the clinical and histopathologic evolution from non-cirrhotic portal hypertension to cirrhosis was documented. In spite of the cessation of pharmaceutical vitamin A intake, the disease progressed. Therapy with colchicine and phenobarbital apparently did not influence evolution to cirrhosis. This suggests that vitamin A can trigger largely unknown mechanisms of liver fibrosis which seem to be self-perpetuating.

Vitamin A absorption in cystic fibrosis: risk of hypervitaminosis A

Vitamin A status was examined in nine adult cystic fibrosis patients and six adult control subjects, together with an assessment of their ability to absorb 10,000 IU of retinyl palmitate from a test meal, taken with appropriate pancreatic enzyme supplements. Median baseline values for plasma retinol and carotene, as well as median serum retinol binding protein concentrations, were significantly lower in cystic fibrosis patients than in control subjects. One cystic fibrosis patient had a raised fasting plasma retinyl ester concentration suggestive of chronic hypervitaminosis A, but no symptoms of toxicity. Measures of vitamin A absorption were also significantly lower in cystic fibrosis patients, although there was considerable overlap with control values. No correlation was observed between measures of baseline status and vitamin A absorption. Measurement of plasma retinyl esters may be an appropriate investigation in those patients considered to be at risk of chronic hypervitaminosis A.

[Portal hypertension and hypervitaminosis A. Apropos of 2 cases and review of the literature]

Portal hypertension consecutive to hypervitaminosis A has seldom been well documented. Two cases are reported here. The first case concerns a 39-year old woman who had taken meladinine (8-methoxypsoralen) for the purpose of tanning. In the second case, a 43-year old woman had absorbed Plethoryl (a combination of tiratricol, cyclovalone and retinol) in order to lose weight. Both patients had histological hepatic lesions, such as hypertrophic Ito cells, perisinusoidal cirrhosis and spontaneous autofluorescence, suggestive of vitamin A overload, associated with a hepatic vein pressure gradient of 10 mmHg or more and high liver concentrations of vitamin A. The responsibility of Plethoryl in case 2 is beyond any doubt, but the mechanism of hypervitaminosis in case 1 is controverted. A review of the literature has provided detailed information on the signs of vitamin A overload, the frequency of which is probably underestimated. Patients with portal hypertension of unknown origin should be investigated for hypervitaminosis A.

Comparative assessment of the toxicology of vitamin A and retinoids in man

As the title implies, any assessment of the toxic effects of vitamin A derivatives must distinguish between vitamin A in the truest sense, i.e. retinol, and retinoic acid and its synthetic derivatives. Just as no single description is universally applicable to the mode of action of vitamin A derivatives, so too do their toxic effects defy generalization. The recommendation made in 1982 by IUPAC [Eur. J. Biochem., 129 (1989) 1] to designate all derivatives with the typical structure of the vitamin as being retinoids may be chemically logical and correct but, when it comes to describing the effects and side-effects of vitamin A derivatives, it leads to misunderstandings. Retinol, which is frequently used as synonym for vitamin A, can eliminate all symptoms of vitamin A deficiency if it is taken in sufficient quantity with the diet. The term retinol will therefore be used here as a synonym for vitamin A whereas retinoic acid and its derivatives--including the synthetic ones--will be referred to as retinoids because they do not cover the whole spectrum of effects exerted by retinol and because they also vary markedly in their side-effects. In contrast to the nomenclature proposed by IUPAC, this system provides a clear and logical distinction for describing biological processes. Other authors have favoured it in recent times [Chytil, F., J. Am. Acad. Dermatol., 15 (1986) 741; Olson, J.A., Semin. Oncol., x (3) (1983) 290; Olson, J.A., Am. J. Clin. Nutr., 45 (1987) 704; Zbinden, G., Acta Dermatovener., 74 (1975) 36]. By vitamin A, therefore, is meant all derivatives that can possibly originate from retinol in the organism. This also covers the small quantities of retinoic acid formed from retinol. On the other hand, by retinoids is meant the natural retinoic acid derivatives and their synthetic forms in their special modes of action. Since retinoic acid cannot be reduced to retinol in the organism, this nomenclature provides a clear demarcation within the biological system. Vitamin A is essential to the growth and development of higher life forms and functions in many different ways within the organism. Although vitamin A was one of the first vitamins to be described, even today there is still some uncertainty as to its mode of action, with the exception of that of retinal (vitamin A aldehyde) in vision.(ABSTRACT TRUNCATED AT 400 WORDS)

Peliosis-like ultrastructural changes of the hepatic sinusoids in human chronic hypervitaminosis A: report of three cases

In addition to hypertrophy of Ito cells and perisinusoidal fibrosis, previously unrecognized ultrastructural abnormalities of the hepatic sinusoids were observed in three patients with chronic hypervitaminosis A: 1) large areas of communication between the sinusoidal lumina and the perisinusoidal spaces, allowing extravasation of blood cells; 2) marked dilation of the perisinusoidal spaces; and 3) swelling and clarification of endothelial cells. Most of these changes, along with some other sinusoidal barrier alterations previously reported in chronic hypervitaminosis A (i.e., bleb formation on the sinusoidal membrane of the hepatocytes and the presence of multiple cellular layers lining the sinusoids), are strikingly similar to those observed in peliosis hepatis. The present findings suggest that sinusoidal barrier abnormalities might constitute a major event in the pathophysiology of vitamin A-induced liver injury as well as of peliosis hepatis.

Liver damage with reversible portal hypertension from vitamin A intoxication: demonstration of Ito cells

A patient with sudden onset of ascites and hepatosplenomegaly made a complete recovery after vitamin A was withdrawn. Fluorescence microscopy on embedded tissue provided a simple method of demonstrating the accumulation of fat storage (Ito) cells in the liver.

Hepatic fibrosis after long-term administration of ethanol and moderate vitamin A supplementation in the rat

Rats were fed up to 9 months diets supplemented with vitamin A in an amount that, by itself, had no apparent adverse effect on the liver. When associated with chronic ethanol administration, vitamin A supplementation strikingly exacerbated ethanol-induced abnormalities: fat accumulation was increased and numerous giant mitochondria were observed. Furthermore, lesions appeared which ethanol alone does not produce in rats, namely necrosis, inflammation, and fibrosis. Vitamin A supplementation increased the number of fat storing cells (lipocytes) which positively correlated with vitamin A accumulation in the liver. However, when vitamin A supplementation was combined with ethanol administration, vitamin A levels in the liver and the number of fat storing cells decreased and numerous myofibroblasts appeared in association with abundant collagen fibers. There was also hepatic inflammation and necrosis, accompanied by a rise in serum glutamate dehydrogenase, SGOT, and SGPT and a decrease in retinol binding protein and vitamin A. We conclude that amounts of vitamin A, which by themselves appear harmless, may produce severe liver lesions when associated with chronic ethanol consumption.