Obesity can lead to liver cancer
Cancer comes with gluttony
Between obesity and the development of liver cancer
there is an undeniable connection, albeit an indirect onePolina Rozentsvet, Newspaper.
Obesity changes the intestinal microflora, intestinal bacteria act on the liver and contribute to the development of cancer. Scientists have traced all the links in the chain that leads from obesity to liver cancer.
The scourge of modern society, at least in developed countries, is obesity, the cause of many ailments. The incidence of cancer is increasing, and with it the list of factors that cause the development of malignant tumors. And finally, we underestimate our microflora, which affects a variety of aspects of the body's condition. These three directions intersected in the work of Japanese researchers led by Dr. Naoko Ohtani (Cancer Institute, Tokyo).
Scientists have proved that excess weight affects the state of the intestinal microflora, and it, in turn, affects liver cells, causing the formation of a malignant tumor.
Actually, experts have noticed the link between obesity and cancer risk for a long time. The task was to decipher the molecular mechanism of this connection. The results of their research were published by Japanese scientists in the journal Nature (Yoshimoto et al., Obesity-induced gut microbial metabolite promotes liver cancer through senescence secretome).
They worked with mice that were kept on a standard diet or fed high-calorie fatty foods. At week 30, the difference in weight was very noticeable: mice of normal fatness weighed an average of 30 grams, overweight - 50, but the researchers did not find differences in the incidence of cancer in mice on different diets. In order for it to manifest itself, the carcinogen dimethylbenzatracene had to be injected into newborn mice. And then, by the age of 30 weeks, all animals on a fatty diet developed liver cancer (it became noticeably enlarged and covered with many small tumors). Similar results were observed in mice that ate normally, but were genetically predisposed to obesity.
Mice with normal weight did not have liver cancer, only 5% had a malignant tumor in the lungs. Therefore, cancer is caused not by diet, but by excess weight.
As a result of complex, painstaking research, scientists have recreated such a chain of events. Obesity changes the qualitative composition of the intestinal microflora of mice. In the bacterial community of obese animals, clostridia begin to multiply rapidly, and only one species, Clostridium sordellii: the proportion of these bacteria is up to 12% of the entire intestinal microflora. Clostridium actively processes one of the bile acids, forming deoxycholic acid (DHA). Its content in the blood serum of mice receiving a fatty diet is increased. This acid has the property of causing DNA damage, and, circulating in the liver, it acts on its stellate cells. Stellate liver cells have several functions, including storing fat and participating in the formation of scar tissue if the organ is damaged.
Under the action of DHA, stellate cells age. Aging is manifested in the fact that cells stop dividing and secrete specific molecules – inflammatory factors and enzymes that break down proteins. Some of these molecules are associated with the life cycle of the cell itself, while others have a broader spectrum of action, including causing inflammation and contributing to the development of cancer.
The risk of malignant tumor formation can be significantly reduced if antibiotics are given to mice. Their intake reduces the number of intestinal bacteria by more than two orders of magnitude, and the number of tumors on one liver is almost twice, and the tumors themselves are much smaller than in the control. You can also reduce the number of aging stellate liver cells or block the formation of DHA – the result will be the same. But taking DHA, on the contrary, contributes to the development of cancer, but only in overweight mice. Slender animals are not afraid of deoxycholic acid.
Thus, the existence of the "obesity – clostridium – cancer" axis can be considered proven.
Some preliminary results allow us to hope that the data obtained in mice are also valid for humans.
Scientists do not exclude that they have not found all the links in this chain and there is an additional factor that causes a malignant tumor and is associated with obesity. But they hope to find all these factors, to find an opportunity to influence them and finally defeat liver cancer. Perhaps it's easier than coping with the obesity epidemic.
Portal "Eternal youth" http://vechnayamolodost.ru27.06.2013