Scientists analyze the relationship between silicone implants and the immune system

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Scientists analyze the relationship between silicone implants and the immune system

How to safely raise your chest How to safely raise your chest How to safely raise your chestScientists analyze the relationship between silicone implants and the immune system Scientists analyze the relationship between silicone implants and the immune system

The research team systematically analyzed how the surface topography of silicone breast implants affects health
.

Image source: Massachusetts Institute of Technology

Approximately 400,000 people in the United States undergo silicone breast implant surgery each year
.

But are these implants safe? The country's Food and Drug Administration (FDA) data show that due to the accumulation of scar tissue and other complications, most implants need to be replaced within 10 years

To this end, researchers from the Massachusetts Institute of Technology and other institutions have studied the morphology and other characteristics of the 5 implants, and systematically analyzed how different surface structures affect the development of adverse reactions, in order to find out which implant designs may be more suitable.
Safe
.

Related papers were published in "Nature-Biomedical Engineering" on June 21

Beauty is risky

Beauty is risky

Silicone is widely used for chronic implants and is generally considered safe
.

In order to reduce the human body’s immune response to silicone implants, designers have taken many measures, such as chemical modification to change the surface chemistry, hydrogel coating, plasma treatment, and changing the topography and roughness of surface features

Among them, silicone breast implants have been used since the 1960s, and the earliest version has a very smooth surface
.

However, implanters often experience a complication called capsular contracture-scar tissue forms around the implant and squeezes it, causing pain and deformation of the implant

In the late 1980s, some companies began to manufacture implants with rough surfaces, some even with textures hundreds of microns thick, hoping to reduce the incidence of capsular contracture and make it better to "stick" to the tissues.
Together, fixed in place
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However, in 2019, the FDA required a breast implant manufacturer to recall all high-texture breast implants (approximately 80 microns) sold in the United States due to an increase in anaplastic large cell lymphoma associated with breast implants ( A type of immune system cancer) risk
.

At present, the new generation of breast implants has a slight roughness (about 4 microns on average), and the number, distribution and size of contact points have been optimized to the cell size to prevent these complications
.

Even so, FDA data shows that all breast augmentation procedures are risky, including anaplastic large cell lymphoma, systemic symptoms commonly referred to as breast implant disease, and capsular contracture

In addition to people who love beauty, some cancer patients and even people with disabilities have to use implants
.

Therefore, more biocompatible implants need to be designed in the future

"It can be said that scientifically based implant design is very important, it can provide patients with safer products
.

" Establishment Labs company Roberto de Mezerville said

Smooth and rough are not good

Smooth and rough are not good

"China Science News" learned from the Massachusetts Institute of Technology that Professor Robert Langer, Johns Hopkins University Assistant Professor Joshua Doloff, Rice University Assistant Professor Omid Veiseh and others have been exploring how the surface of the implant interacts with The surrounding tissues interact with the immune system
.

Veiseh, one of the authors of the paper, told reporters: "The surface morphology of the implant can greatly affect the immune response to its perception
.

Therefore, the design of the implant has an important impact on the safety of use
.
We hope this paper can help plastic surgeons Evaluate and better understand how the choice of implant affects patient health
.
"

They first tested five implants on the market, including the highly textured, completely smooth implants that were recalled before, and three implants with a roughness between the two
.
Two of the implants have a new surface structure, one with a roughness of 4 microns and the other with a roughness of 15 microns
.

"We used the same base material/chemical composition as the commercial implants currently approved on the market, and hope that our data is as clinically relevant as possible,
" Doloff told China Science Daily
.

In a rabbit study, the researchers found that the tissue surrounding the roughest implant showed signs of increased macrophage activity
.
Macrophages are immune cells that can remove foreign cells and debris
.
Moreover, all implants stimulate immune cells called T cells, but in different ways
.
The rough-surfaced implant stimulated more pro-inflammatory T cell responses
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These findings indicate that rough implants rub against surrounding tissues and cause greater irritation
.
This may explain why rough implants may cause lymphoma: some surface particles fall off and become trapped in nearby tissues, causing chronic inflammation and eventually cancer
.

The researchers also tested miniature versions of these implants in mice and finally reached similar conclusions
.
For example, rougher implants stimulate more macrophage activity, higher levels of inflammatory T cells, and form more scar tissue
.
They also performed single-cell RNA sequencing on these immune cells to confirm that the cells express pro-inflammatory genes
.

"Although the completely smooth surface implants also led to higher levels of macrophage response and fibrosis, it is clear that in mice, the rough implants put more pressure on individual cells and expressed more Pro-inflammatory phenotype
.
" Doloff said
.

Choose carefully

Choose carefully

After the animal experiments, the researchers analyzed a large number of cancer tissue samples from MD Anderson Cancer Center to study the human body's response to different types of silicone breast implants
.

In these samples, the researchers saw the same type of immune response as in animal studies
.
They observed that over the years, tissue samples from users of high-texture implants showed signs of chronic, long-term immune responses; these patients had thicker scar tissue
.

"We have seen consistent and similar effects in mice, rabbits and humans
.
Although one might say that there are species-specific differences, the degree of conservation of immune and fibrotic responses is quite significant
.
" Doloff said, "Compared In general, implants with a roughness of 4 microns are the best in reducing foreign body reactions, fibrous capsule formation and inflammatory immune responses
.
The reason may be that the surface structure is similar to the surface of cells, allowing cells to perceive them in different ways
.
"

The researchers hope that the results can help other researchers optimize the design of silicone breast implants and other types of medical silicone implants for better safety
.

"We hope to bring new material science methods to better understand the biocompatibility issues in the field of breast augmentation
.
We also hope that this research will help design safer and more effective implants
.
" said Langer, the senior author of the study.

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In the next step, the researchers plan to analyze whether the best implants that can reduce scarring and inflammation can work in cancer patients
.
Because early cancer treatments, such as chemotherapy, radiotherapy or other interventional procedures, can lead to fibrosis and a higher rate of implantation failure
.

Related paper information: https://doi.
org/10.
1038/s41551-021-00739-4