Stem cell studies pave way for novel bone repair pastes

WASHINGTON - Researchers at the University of Maryland Dental School have conducted new stem cell studies that may pave the way for the use of strong, mouldable, and injectable pastes to regenerate needed bone tissue to repair broken bones, fractures, genetic defects, even combat bone wounds.

Dr. Huakun Xu, Dr. Michael Weir and Ryan Zhao at the Dental School showed that human stem cells seeded in a tissue engineering scaffolding exhibited “excellent attachment and osteogenic differentiation,” which is the process of laying down new bone material.

The researchers said that the new findings have triggered hopes that an injectable paste of stem cells will be available one day to fill any shape of cavity from bone defects, breaks or wounds by regenerating needed bone tissue.

In test tube studies, stem cells from bone marrow, when placed into an injectable scaffold of calcium phosphate and chitosan, started growing and forming minerals needed for new bone tissue.

So far, the researchers have tested four scaffolding materials for gripping and holding the stem cells.

“Which of the materials will be used in a commercial product really depends on where you want to place the material, whether in the jaw bone, the cranium or other bones,” said Weir.

He added: “Ultimately we want this to be an injectable paste so we can put it into voids that are not square, rectangular or circular, that they are irregular shapes that need to be filled. The paste will include the cells.”

Xu said that such a product could also be used in periodontal bone repair, mandibular and maxillary ridge augmentation, reconstruction of frontal sinus and craniofacial skeletal defects, and other stress-bearing orthopedic applications.

He said that after a tumour removal or traffic accident, there might be a need to repair the damage or void left. Thus, it will be beneficial to have a paste that can be shaped easily to achieve a high degree of aesthetics.

After shaping, the paste hardens to form a solid scaffold full of pores and channels and still containing stem cells throughout, still living and growing to form new bone.

Eventually the scaffold material degrades and is replaced entirely by new bone tissue grown from the stem cells.

The researchers found that a significant number of the cells were alive after a few weeks in the scaffolding material.

They then discovered that the cells were differentiating into osteoblasts, essentially turning into bone cells.

Weir said that after staining the scaffold, the researchers found that the osteoblasts were forming “a lot” of the mineral, which then forms the bone after only 21 days.

In a subsequent experiment, the cells survived even better when mixed in a gel of the scaffolding material.

The researchers have recorded similar success with umbilical cord-derived stem cells, which “appear to be more potent in terms of growth and transforming into osteoblasts on the scaffold than the cells from bone marrow,” said Xu.

The researchers presented their findings at the World Stem Cell Summit at the Baltimore Convention Center. (ANI)