Contractile tissues, vitamin

In intestinal tissue, vitamin E has little or no effect in normoxia. A study [221] using rabbit intestine showed that vitamin E had a weak inhibitory action which was direct and independent of adrenergic or cholinergic nervous influences. In guinea-pig colon, the vitamin was without action in normoxia. In hypoxia, where the spontaneous contractile activity was replaced by quiescence, vitamin E delayed the decline in activity [222], However, once hypoxia had been achieved, vitamin E was able to induce an increase in contractile activity. 

Hepatic stellate cells (HSC) are star-shaped cells with long cytoplasmic extrusions. They were first described over 150 years ago hy von Kupffer, but for many years their function remained a mystery. They are found in the space of Disse adjacent to the overlying endothelium and hepato-cytes, and in the normal liver they represent 5-8% of all liver cells. Under resting conditions HSC store retinoids in numerous vitamin A-rich lipid droplets and are thought to regulate sinusoidal blood flow via contractile intracellular filaments. HSC are the principal cells involved in liver fibrosis, remodelling extracellular matrix and synthesising scar tissue in response to liver injury. 

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