Health

Improving biomaterials design for bone regeneration

Electron microscopic image of a mineralized collagen scaffold showing mineral crystals and collagen fibers. Colors have been added by researchers. Credit: Marley Dewey

Injuries to the facial and skull bones, known as craniofacial defects, can be caused by sports injuries, vehicle accidents, or battlefield injuries. Repairing such defects is complicated because different types of cells need to interact with each other. In a new study, researchers are investigating the types of materials used for reconstruction to see which ones are most effective.

More than 2 million bone grafts are performed worldwide each year. Bone defects in CMF are usually irregularly shaped and are often repaired using regenerated biomaterials.Harley Lab develops collagen scaffold A biomaterial containing components contained in bone such as calcium ions and phosphate ions, and a sugar compound called glycosaminoglycan (GAG).

“Our lab focuses on the development of degradable biomaterials (also known as scaffolds) for bone and tissue repair,” said Vasiliki Kolliopoulos, a graduate student in Harley’s lab. Stated. “There are many types of cells in the bone environment that contribute to healing. Stem cells Monocytes that form bone, and Immune response.. In this study, we investigated how scaffolding materials affect the combined behavior of these different cells. “

Researchers have adapted collagen biomaterials to contain one of three different types of GAG (chondroitin-4-sulfate, chondroitin-6-sulfate, and heparin) found in the microenvironment of bone tissue. .. Next, we investigated how these GAGs affect processes important to bone regeneration, such as stem cell activity, immune cell activation, and endothelial cell activity, which is important for the formation of new blood vessels.

To do so, stem cells were added to the scaffold and the surrounding solution or medium was collected for up to 21 days. Stem cells are a powerful factory of molecules that can affect other cells in the wound environment. After collection, conditioned medium was added to the culture of endothelial cells found in blood vessels. “For bone regeneration, Blood vessels Few people have seen how scaffolding materials affect endothelial cells and improve bone repair, “said Marley Dewey, a former graduate student at the Harley Institute.

Researchers followed the growth of endothelial cells for 6-12 hours. “Heparin is known to have a direct effect on angiogenesis, but surprisingly, the medium produced by the stem cells of the chondroitin-6-sulfate scaffold is the largest amount compared to the other two scaffolds. It was found that it led to the development of blood vessels in the body, “said Kolliopoulos. ..

Habituation media have also been studied to determine the type of molecule known as a soluble factor that aids in the development of blood vessels and bone. Finally, researchers added conditioned medium to monocytes and followed their growth for 21 days to determine the type of immune cells they altered. They found that the type and number of soluble factors varied by scaffold type, and that chondroitin-6-sulfate medium produced the maximum number of immune cells that helped during the inflammatory response.

Researchers plan to further investigate the response of immune cells. “Stem cells can signal monocytes when the body warns that something is wrong. Therefore, do stem cells that grow on scaffolds in an inflammatory environment secrete cocktails with different soluble factors? I would like to see if you can, “says Kolliopoulos. ..

“These results show that soluble factors play an important role in these multicellular systems,” says Kolliopoulos. “We have shown that there are differences in cellular responses depending on the materials used. It is important to understand these interactions before proceeding to more complex experiments.”

It is unclear which aspects of the scaffolding material contribute to the difference between growth factors and cell growth, which is the next issue the Harley Institute will address. “After identifying how the scaffolding affects cell, We want to combine different cell types to see what happens, “says Kolliopoulos. Bone defect. It is important to understand how these materials work on multiple cell types. “

Mai Ngo, the third author of the treatise, helped to understand the development of blood vessels. The paper “Glycosaminoglycan content in mineralized collagen scaffolds promotes mesenchymal stem cell secretion, a factor that regulates angiogenesis and monocyte differentiation,” was published. Material rear..


Skeletal scaffolding supports bone cells and blood vessels


For more information:
Marley J. Dewey et al, Glycosaminoglycan content in mineralized collagen scaffolds promotes mesenchymal stem cell secretion, a factor that regulates angiogenesis and monocyte differentiation. Material rear (2021). DOI: 10.1016 / j.mtla.2021.101149

Quote: Improvement of biomaterial design for bone regeneration (September 13, 2021) from https: //medicalxpress.com/news/2021-09-biomaterials-bone-regeneration.html on September 13, 2021 Obtained.

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