Tachosil - Report Fails to Impress

A new product — a sponge-like patch — is now on the market to help decrease bleeding during cardiovascular surgery.
The sealing patch, called TachoSil, helps prevent bleeding and — better yet — never needs to be removed. It simply dissolves within the body over time.
“TachoSil is the first absorbable fibrin sealant patch for use in cardiovascular surgery to prevent mild and moderate bleeding from small blood vessels when standard surgical techniques are ineffective or impractical,” said Dr. Michelle Yeboah.
The new product received approval in April from the Center for Biologics Evaluation and Research, the part of the Food and Drug Administration that regulates biological products for human use.
The absorbable fibrin sealant patch is unique. It is the first product of its kind available in the United States, said Laura Jacobs, corporate communications official with Baxter Pharmaceuticals.
Officially, the patch is considered an adjunctive hemostatic agent, used to control bleeding during surgery, Jacobs said.
TachoSil is a sponge-like material made up of naturally occurring proteins found in mammals. The product is covered with two proteins: fibrinogen and thrombin.
Together they cause chemical reactions that produce fibrin, which is a protein that brings about blood clots.
This sealant patch is biodegradable, which means that it breaks down within the body in less than six months.
TachoSil does not require preparation and can be applied directly to the bleeding area during both open and minimally invasive surgeries.
“In the presence of saline, blood or other bodily fluids, the coagulation factors in TachoSil dissolve to form a mechanical fibrin clot, which adheres the patch to the bleeding surface and achieves hemostatis,” Jacobs said.
It can be used in cardiovascular surgery when bleeding cannot be controlled by standard surgical techniques such as suture, ligature or cautery. It is not a replacement but rather an additional tool to what is currently available to surgeons.
The patch comes in various sizes. The surgeon can use scissors to cut the patch to a specific size or can overlap patches if the patch is not large enough.
In instances of heavy bleeding, excess blood is to be wiped away before TachoSil is applied.
One side of the patch is yellow, and that is the side that should cover the wound. It is dyed with riboflavin to indicate that the side contains active ingredients.
It is critical to apply pressure on the patch for three minutes.
After the surgery, imaging scans such as X-rays, ultrasounds and CT scans will show evidence that TachoSil was used. The clarity of the image depends on the specific site of application.
No product comes without risk, however.
It is not common, but some patients experience hypersensitivity or allergic reactions. In rare cases, it could turn into severe hypersensitive reaction. Those who are prone to having a systemic reaction to horse proteins or human blood products are not good candidates for use of TachoSil.
TachoSil comes in double packaging which makes it extra sterile. This allows someone to assist during surgery and open one layer of the package while leaving the inner package on the table with the other instruments ready for use.
The sealant patch is a significant advance for cardiologists and represents another tool surgeons can use to address the many types of bleeding challenges in cardiovascular surgery, Jacobs said.
TachoSil has more than 15 years of documented clinical experience and a strong safety record, Jacobs said.
The product, manufactured by Nycomed Austria, is available in more than 50 markets, in addition to the United States.

Source: Reporter News

Researchers Study Molecular Architecture of Fibrin Networks

The research, published by Cell Press in Biophysical Journal on May 18th, provides insight into how the molecular architecture of a fibrin network contributes to its resilience and may help to explain what causes the failure of a clot, which can lead to a stroke or heart attack.

Fibrin is a fibrous protein which assembles into a remarkably strong spider web-like gel that forms the structural framework of blood clots. Previous work has shown that fibrin networks, thought to be among the most resilient proteins in the natural world, stiffen when deformed and become increasingly resistant to further strain. Although this extraordinary resilience appears to be crucial for the biological function of blood clots, the molecular basis of this resilience is not well understood.

"To better understand the superior elasticity of fibrin networks, we measured the mechanical behavior of purified fibrin gels on multiple scales," says senior study author, Dr. Gijsje H. Koenderink from the Biological Soft Matter Group at the FOM Institute AMOLF in The Netherlands. "We found that the fibrin has a series of molecular domains that are stretched out sequentially, on smaller and smaller scales, when clots are deformed. This stretching leads to gel stiffening, which protects the clots from damage"

Specifically, Dr. Koenderink's group made the surprising discovery that the fibrin fibers are very porous loose bundles of thin filaments that are connected by flexible crosslinkers. This open structure (containing 80% water) makes the fibers 100-fold more flexible than previously thought, and enables sequential stiffening due to straightening out of the bundles between network crosslinks followed by straightening out of flexible protein domains inside the bundles. "We found that it is this bundle-like structure of fibrin fibers that is ultimately responsible for the superior mechanical properties of fibrin gels," explains Dr. Koenderink.

The researchers presented a theoretical model that explained their observations in terms of this unique hierarchical architecture of the fibers. "Our data reveal molecular design principles that allow blood clots to recover from large forces, such as shear forces from blood flow, furthering our understanding of how pathological alterations in fibrin cause clot rupture and bleeding or thrombosis," concludes Dr. Koenderink. "Moreover, our findings suggest a new design concept for resilient bio-inspired materials with potential applications in drug delivery and tissue repair."