Arushi Bidhuri
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Written By: Arushi Bidhuri | Updated : June 24, 2021 10:02 PM IST
Smoother Silicone Breast Implants Lessen Intensity Of Immune System Reactions
A study published in Nature Biomedical Engineering found that smoother silicone breast implants have a lower chance of causing inflammation and other immune system reactions than those with rougher textured coatings. The trials, which used mice, rabbits, and human breast tissue samples, increase knowledge of how the body reacts to such implants, providing fresh information to doctors and confirming the benefits of particular smoother surfaces, according to the researchers.
Breast implants can be filled with saline or silicone, and both varieties include a silicone outer shell. They are surgically implanted after mastectomies or to augment breast size. Previous research has shown that the majority of the 400,000 women who have silicone implants in the United States each year will need to have them replaced within 10 years due to pain and shape-shifting caused by immune system cells that lead to scarring and fibrous tissue.
Joshua Doloff, PhD, assistant professor of biomedical engineering at The Johns Hopkins University and a first author of the research, which began during his postdoctoral training at MIT said, "Our aim is to provide patients with as much information as possible so they can make informed decisions to guide their own personal health."
Scientists have long known that the immune system biologically walls off alien things in the body by causing inflammation and scarring, which may be disfiguring and painful, according to Doloff, whose study focuses on the interaction between implanted devices and the human body.
Scientists have been studying how to build implant surfaces in such a way that these effects are minimised for the past decade. Previous research has revealed that implants with perfectly smooth coverings cause severe immune rejection over time.
As a result, implant makers began marketing implants with textured surfaces to combat immune system rejection and "attach" to human tissue like Velcro, allowing for a better and more secure location in the body. According to the researchers, more than 90% of breast implants used in the United States are smooth, however, most implants used outside of the United States are not.
Because of its links to greater incidence of breast implant-associated anaplastic large cell lymphoma among patients with these "macro textured" implants, an implant with the highest degree of the textured surface was pulled off the market in the United States in 2019.
The results of implanting small replicas of implants with five distinct surface designs in mice were examined in the current study. One implant had a perfectly smooth surface, while another had a slightly curved surface at the level of a single human cell, as well as others with varied surfaces. They also implanted one with a 90-micron macro textured surface, similar to the implants removed off the market.
Establishment Labs assisted in the production of the mini-implants, which were made using industry-standard manufacturing procedures.
Establishment Labs, which funded the research, also manufactures two full-scale commercial implants, including one with a surface design that includes a roughness of about 4 microns on average and other characteristics like skewness and the number, distribution, and size of contact points.
When compared to the 90-micron implant, the implant with design elements such as a 4-micron surface roughness resulted in the least fibrous tissue surrounding it roughly 10 times less at three weeks and six months post-implantation.
The highest activity of the gene FOXP3 was found in tissue surrounding implants in mice and rabbits with a 4-micron roughness, indicating the production of more immune cells called Tregs, which act as traffic cops to reduce the amount of inflammation and fibrous tissue created by the immune system cells.
The researchers also examined the gene expression levels of certain cell types in the tissue surrounding implants in mice and discovered that genes associated with pro-inflammatory responses, such as STAT1 and CXCL10, rise five to tenfold with more heavily textured implants.
At the University of Texas MD Anderson Cancer Center in Houston and the Costa Rican Institute for Research and Teaching on Nutrition and Health Foundation, tissue was obtained from implants removed from 15 healthy people.
Patients who had implants with a 4-micron surface roughness had much less fibrous tissue formation around them than those who had more strongly textured implants or those who had implants that were entirely smooth.
Other areas of ongoing study for implantable devices, according to Doloff, include the development of biosensors that can detect tissue rupture, leakage, or inflammation. He believes that the surface design, which includes a 4-micron roughness, could be useful in biomaterials other than breast implants. He also wants to look into the degree of immune reaction, inflammation, and fibrous tissue in women's implants after they've been diagnosed with cancer and treated.
"Engineers should know how something works, not just that it works, so we can improve on existing technologies, says Doloff.
(with inputs from agencies)
