A histomorphometric study of the effect of chronic vitamin A deficiency on the circumvallate papilla of the rat

[Changed taste perception in patients with eating disorders]

OBJECTIVE

Taste is a hereditary trait and affects eating and dietary behavior. The tongue's papillae represent the first line of the gustatory apparatus to provide information about taste. The aim of the present investigation was to evaluate the number of fungiform papillae (fPap) in relationship with 6-n-propylthiouracil (PROP) sensitivity and body mass index (BMI) in patients with eating disorders.

METHODS

18 female patients with eating disorders (anorexia or bulimia nervosa; age 14-20 yrs.) and 15 age-matched female controls were included. The number of fPap was quantified. Bitter taste was probed with PROP. Different BMIs (e.g. minimal BMI, maximal BMI) were calculated.

RESULTS

As regards non-tasters (PROP negative), anorectic patients showed a significant reduction in the number of fPap compared to both PROP negative healthy controls and also bulimic patients. The number of fPap did not differ significantly between tasters and non-tasters within controls and eating disorder groups. There was a trend of higher BMI's in bulimic and healthy non-tasters.

CONCLUSIONS

In anorectic patients a reduced number of fPap was associated with a decreased PROP sensitivity, which is a new finding. The data of the present study support the notion that the variation of fPap number and PROP sensitivity influences the pathophysiology of eating behavior and taste perception, and following this are involved in the development of eating disorders.

Vitamin A deficiency enhances docosahexaenoic and Osbond acids in liver of rats fed an α-linoleic acid-adequate diet

The synthesis of docosahexaenoic (DHA, 22:6n-3) and Osbond acid (OA, 22:5n-6) is regulated by the heterodimer of peroxisome proliferator-activated receptor and retinoid X receptor (RXR). 9-Cis retinoic acid, a metabolite of vitamin A, is the most potent ligand of RXR. We tested whether vitamin A deficiency impairs DHA and OA synthesis in rats fed a vitamin A- and alpha-linolenic acid (ALA)-sufficient (VASALAS), vitamin A-sufficient and ALA-deficient (VASALAD), vitamin A-deficient and ALA-sufficient (VADALAS), or vitamin A- and ALA-deficient (VADALAD) diet. After 7 wk of feeding, liver and colon choline (CPG) and ethanolamine (EPG) phosphoglyceride FA were analyzed. The VADALAS compared with the VASALAS rats had elevated levels of both DHA (P< 0.05) and OA (P < 0.005) in liver CPG and EPG. In contrast, the VADALAD group had a lower DHA (P < 0.01) and higher OA (P < 0.005) level in CPG and EPG of both tissues than their VASALAD counterparts. ALA deficiency reduced DHA and enhariced OA levels in liver and colon CPG and EPG in both the vitamin A-sufficient (VASALAS vs. VASALAD) and -deficient (VADALAS vs. VADALAD) rats (P < 0.005). The study demonstrates that ALA deficiency reduced DHA and enhanced OA levels in tissue membranes, and dietary vitamin A deficiency has a profound effect on membrane DHA and OA in rat tissues. Both vitamin A and DHA are involved in a myriad of vital physiological functions pertaining to growth and development and health. Hence, there is a need for a further study to unravel the mechanism by which vitamin A influences membrane DHA and OA.

Cell type-specific expression of beta-carotene 15,15'-mono-oxygenase in human tissues

We studied the cell type-specific expression of human beta-carotene 15,15'-mono-oxygenase (BCO1), an enzyme that catalyzes the first step in the conversion of dietary provitamin A carotenoids to vitamin A. Immunohistochemical analysis using two monoclonal antibodies against different epitopes of the protein revealed that BCO1 is expressed in epithelial cells in a variety of human tissues, including mucosa and glandular cells of stomach, small intestine, and colon, parenchymal cells in liver, cells that make up the exocrine glands in pancreas, glandular cells in prostate, endometrium, and mammary tissue, kidney tubules, and in keratinocytes of the squamous epithelium of skin. Furthermore, BCO1 is detected in steroidogenic cells in testis, ovary, and adrenal gland, as well as skeletal muscle cells. Epithelia in general are structures that are very sensitive to vitamin A deficiency, and although the extraintestinal function of BCO1 is unclear, the finding that the enzyme is expressed in all epithelia examined thus far leads us to suggest that BCO1 may be important for local synthesis of vitamin A, constituting a back-up pathway of vitamin A synthesis during times of insufficient dietary intake of vitamin A.

Ultrastructural changes in the organ of Corti and in the ganglion spiral cochleae after vitamin A deficiency

Guinea pigs were fed a vitamin A free diet and the cochleae of these animals were studied with the light and electron microscope. No changes could be found after ten weeks of vitamin A deficiency, but after 19 weeks the experimental animals showed a slight hypertrophy of the otic capsule, an accumulation of lysosomes in the sensory cells and a disruption and disintegration of the Hensen body. In the ganglion spiral cochleae ganglion cells appeared, filled with different myelin figures or honeycomb-like inclusions. Furthermore, the myelin sheath was split and sometimes filled with circular lamellar complexes and glycogen. These morphological findings together with the evidence of high concentrations of vitamin A in the organ of Corti support the hypothesis that vitamin A may be important for the function of the n. acusticus.