Antibody staining against fibrillin-1 showed no evident morphological differences in distribution between experimental and control embryos in the lens, suggesting that fibrillin-1 was not the cause, and malformations may be attributed to other mechanisms.

Several countries have approved universal folic acid (FA) fortification to prevent neural tube defects and/or high homocysteine levels; this has led to a chronic intake of FA. Traditionally, the vitamin is considered to be safe and nontoxic, except for the potential masking of vitamin B-12 deficiency. Recent reports from our laboratories showed several effects of high-dose folate supplementation in rats. In this work, we compared the effect of FA on the liver of weanling (3 wk) and aged (18 mo) male rats fed either a diet supplemented with 40 mg FA/kg diet or a control diet (1 mg FA/kg diet) for 4 wk. FA supplementation did not alter serum aspartate aminotransferase, alanine aminotransferase, urea, glucose oxidase, total bilirubin, or uric acid. Routine histological staining as well as immunohistochemistry with proliferating cell nuclear antibody for dividing cells, and cytokeratin-8 against bile ductal cells, showed that aged, supplemented rats had the same number of hepatocytes as both control and supplemented weanling rats, and tended to have more (17%, P = 0.07) hepatocytes than aged, control rats. Moreover, the bile duct cells of aged, control rats proliferated and transformed into cholestatic rosettes at a higher frequency than in aged, supplemented rats. The morphology of the liver in weanling rats was similar in both diet groups, and comparable to the supplemented, aged rats, thus indicating that a high intake of FA improves normal liver morphology in livers of aged rats.

Fibrillin-1 protein is a microfibrillar glycoprotein component of the extracellular matrix, widely distributed in ocular connective tissues. In this work, we show for the first time the expression pattern of fibrillin-1 protein in the corneal and conjunctival epithelia and in stromal keratocytes during embryo development. After hatching, protein expression was maintained in the corneal epithelium cells and nonsecreting epithelium cells of the conjunctiva and disappeared in the stromal keratocytes. In the limbus region, the basal cells were negative, while superficial cells were positive for the antibody. The expression in corneal epithelial cells suggests a role for fibrillin in development and disease. Therefore, some basal cells of the limbus region do not show fibrillin-1 immunolocalization, and this may be correlated with stem cell or stem-like properties.