Silicone implants affect immunity

Silicone breast implants are placed not only when you just want to correct the shape of the breast, but also after operations associated with injuries or removal of a breast tumor. They have been used since the 60s of the last century, and since then several generations of implants have changed. The former were smooth, but due to the smooth surface, they were often problematic. For example, smooth implants changed their position in the tissues, so a new operation had to be done to correct them or even remove them altogether; often complications arose with them, such as capsular contracture – the thickening of the connective tissue around the implant, which squeezed it, causing severe inconvenience.

In the late 1980s, implants with a rough surface appeared, which eliminated the disadvantages of smooth implants. But then it turned out that rough implants increase the risk of certain types of lymphomas – malignant diseases of the immune system. The roughness of the implants was reduced, in addition, the surface of the following implants was generally heterogeneous: they were created taking into account where and how they come into contact with living tissues, and what kind of tissues surround the implant. But whatever the implant is, it still remains a foreign body for the immune system, and the question is how much it irritates it.

Staff Massachusetts Institute of Technology together with colleagues from the Johns Hopkins Institute and other research centers describe in Nature Biomedical Engineering the results of many years of experiments with silicone implants, which were implanted in laboratory rabbits. Among the implants were very different, there were also very rough ones that are no longer used, there were also the newest models in which the surface was divided into different topographic zones, with more or less unevenness.

It turned out that different cells of the immune system react to implants in different ways. If we talk about macrophages that eat dead cells, foreign substances and in general any debris, then their activity increased regardless of the type of implant. Speaking of T cells, the very rough implants stimulated an inflammatory response in them. If the roughness of the implant was small, about 4 microns, and if its surface was heterogeneous in this sense (that is, it was created taking into account a different cellular environment), then with such an implant, T-cells tried to suppress inflammation.

It is known that cancer is closely related to chronic inflammation. Obviously, lymphomas in women with implants also occurred due to the fact that rough implants constantly heated up the inflammatory response. Researchers believe that with too rough implants, small pieces of material come off the protrusions on the surface, sink into the surrounding tissue and begin to irritate it greatly.

The implant experiments were repeated in mice, with similar results. Smooth implants stimulated macrophages more strongly, and in response to smooth implants, connective tissue grew more strongly. But if we talk about inflammation, then it developed most strongly in response to implants with a very rough surface. In general, the most successful from the point of view of immunity are those implants whose roughness is on average about 4 microns and whose surface is complex, heterogeneous: such implants least of all provoke connective tissue to grow, and with them the immune cells are best kept from inflammation.

The connection between the type of implant and oncological diseases was shown on tissue samples taken from real cancer patients. For those with rough implants, the tissues around them formed more powerful scars (that is, the connective tissue reacted more strongly to the implant) and the immune cells were in a state of more severe inflammation. Actually, even the most harmless implants in this sense, slightly rough and with a complex surface, also cause an immune response, and connective tissue scars also appear with them. But with new data, at least it becomes clear in which direction to move in order to make such implants that would not threaten women’s health at all.

Source: Автономная некоммерческая организация "Редакция журнала «Наука и жизнь»" by

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