Monday, March 26, 2012

Computer chip analyses effect of food on intestines

Processing the components from our food is quite a stressful event for our intestines. Various enzymes are needed to break down whatever it is we eat, and all the useful pieces need to be absorbed in the gut and find their way into the blood to be redistributed where needed. Tissues can become strained from all the work, and then send out distress signals which enable the immune system. In turn, this causes inflammation. Because processing food is naturally stressful, a little inflammation is normal. However, when food components continuously stress the intestines, inflammation can become chronic, and that is when trouble starts. To uncover which food components are more likely to cause stress in the intestines, French scientists developed a piece of computer hardware. Their chip is supposed to mimic our gut and tell us something about what individual food components do.

A high resolution CMOS sensor is built into the device, called NutriChip, and is used to detect molecules that stimulate an immune response, thereby increasing inflammation. The optical sensor is able to visualize what happens on the 'other side' of the intestinal wall where cells normally produce these signalling molecules, called cytokines. Food components passing through the lumen of the gut need to get themselves to the other side, where the blood vessels are located. When the gut responds by producing stress signals, it sends immune cells hurrying through the blood to the site of inflammation. The NutriChip is supposed to mimic this system with artificial layers of cells. An upper layer mimics the intestinal cellular lining that comes into contact with the food. A lower layer mimics the circulatory system which includes the blood vessels required to transport the absorbed food, and both layers are separated by an artificial membrane.
NutriChip: an artificial gut built into an optical system connected to a circuit board.
By applying various food components to the upper layer of the NutriChip, scientists mimic the food uptake process. Absorbed molecules pass through the cellular layers and end up in the circulatory system. The chip then measures what happens to the cytokine levels. In addition, it is possible to measure other components of the immune system to derive whether the effect of a given food component is inflammatory or anti-inflammatory. This is done for various food components, and by comparing the concentrations, the measurements tell us something about how inflammatory a particular digested food component is.

How inflammatory our food is has been subject to debate for quite a while. We have already shown that processing food is a cumbersome and stressful event for our intestines. One of the topics in the food industry revolves around milk: the question is whether milk has an inflammatory or anti-inflammatory effect. Preliminary studies suggest it has an anti-inflammatory effect, but this calls for more research. The NutriChip needs to provide us with answers to this debate. An experimental model has been set up where a mixture of molecules, derived after enzymes break down milk to individual components, will be applied to the chip. No results have been published as of yet. Naturally, the artificial gut will also be used to assess the effect of other components.
The absorptive epithelium is the outer most part of the intestines. This is where the food  components are taken up by the body. Capillaries (very small blood vessels) can be found in the lamina propria, a mucosal layer just beneath the absorption layer.

A larger overview: the absorptive epithelium is part of hair-like structures called microvilli.  Their structure increases surface area and therefore also food uptake rates. The capillary network follows the microvilli structure and transports food components back to the big vessels lying deeper inside the gut. Lymph nodes are part of the immune system, and also function by transporting fluids.

No comments:

Post a Comment