Increased cholesterol levels increases cholesterol formation 100 times faster: study

Researchers have found that increased cholesterol levels in mice are associated with an increase in tumour formation. Researchers from the David Geffen School of Medicine at UCLA found that boosting the animals' cholesterol levels spurred intestinal stem cells to divide more quickly, speeding up the rate of tumour formation 100 times.

The results in mice could also hold true for humans, according to experts. Butter, cheese and other products containing high levels of cholesterol might increase the rate of tumour formation in people who have a tumour. The study has identified a molecular pathway which could be a new drug target in colon cancer treatment.

Study author Dr Peter Tontonoz says, ''We were excited to find that cholesterol influences the growth of stem cells in the intestines, which in turn accelerates the rate of tumour formation by more than 100-fold. While the connection between dietary cholesterol and colon cancer is well established, no one has previously explained the mechanism behind it.''

The team added to the level of cholesterol in the intestinal stem cells of mice by introducing more of the substance into their diets. In another group, the researchers altered a gene that regulates phospholipids, the primary type of fat in cell membranes, which spurred the cells into producing more cholesterol on their own.

They found that the ability of the stem cells' to multiply increased in both groups.

According to experts, the next challenge is to find out whether the same cholesterol effect can be observed in other types of cancers, as well as finding methods for stopping it. They say if the same results can be recorded in humans, we could have a new way of fighting colon and other cancers.

They say the research would also help in the ongoing debate over whether statins, drugs which can lower the level of "bad" cholesterol or low-density lipoprotein (LDL) in the blood can also reduce the risk of cancer.