Bone Regeneration

Researchers have identified a subpopulation of mesenchymal stem cells (MSCs) that boost the healing of bone fractures and show an ability to differentiate into various cell types.

Their findings are published in the journal Bone Reports in a paper titled, “Bone marrow CD73+ mesenchymal stem cells display increased stemness in vitro and promote fracture healing in vivo,” and led by researchers from the University of Tsukuba (Japan), in collaboration with the University of Bonn, Germany.

MSCs are multipotent and considered to be of great potential for regenerative medicine,” the researchers wrote. “We could show recently (Breitbach, Kimura, et al. 2018) that a subpopulation of MSCs, as well as sinusoidal endothelial cells (sECs) in the bone marrow (BM) of CD73-EGFP reporter mice, could be labeled in vivo. We took advantage of this model to explore the plasticity and osteogenic potential of CD73-EGFP+ MSCs in vitro and their role in the regenerative response upon bone lesion in vivo.”

The generation of the callus is critically dependent on the recruitment of MSCs from the surrounding tissue and the bone marrow,” explained Kenichi Kimura, PhD, lead author and assistant professor at the University of Tsukuba. “Therefore, fracture healing models are helpful for exploring the cellular dynamics of MSC migration and differentiation during tissue regeneration.”

The new finding of the subpopulation of MSCs paves the way for new regenerative medicine and the treatment of fractures to be made.

Our study underscores the heterogeneity of BM-MSCs and their differential response and mobilization upon bone fracture. We found that the CD73+ subpopulation of BM- MSCs contributes to the regeneration process of bone fracture healing by promoting callus formation and that also the BM sEC fraction participates in the neovascularization process during bone repair,” concluded the researchers.

Source: https://www.genengnews.com/

How to Speed up Bone Implant Recovery

An international research team led by Monash University has uncovered a new technique that could speed up recovery from bone replacements by altering the shape and nucleus of individual stem cells. The research collaboration involving Monash University, the Melbourne Centre for Nanofabrication, CSIRO, the Max Planck Institute for Medical Research and the Swiss Federal Institute of Technology in Lausanne, developed micropillar arrays using UV nanoimprint lithography that essentially ‘trick’ the cells to become boneNanoimprint lithography allows for the creation of microscale patterns with low cost, high throughput and high resolution.

When implanted into the body as part of a bone replacement procedure, such as a hip or knee, researchers found these pillars – which are 10 times smaller than the width of a human hair – changed the shape, nucleus and genetic material inside stem cells. Not only was the research team able to define the topography of the pillar sizes and the effects it had on stem cells, but they discovered four times as much bone could be produced compared to current methods.

Novel micropillars, 10 times smaller than the width of a human hair, can change the size, shape and nucleus of individual stem cells and ‘trick’ them to become bone

What this means is, with further testing, we can speed up the process of locking bone replacements with surrounding tissue, in addition to reducing the risks of infection,” Associate Professor Jessica Frith from Monash University’s Department of Materials Science and Engineering said. “We’ve also been able to determine what form these pillar structures take and what size they need to be in order to facilitate the changes to each stem cell, and select one that works best for the application.

Researchers are now advancing this study into animal model testing to see how they perform on medical implants. Engineers, scientists and medical professionals have known for some time that cells can take complex mechanical cues from the microenvironment, which in turn influences their development.

However, Dr Victor Cadarso from Monash University’s Department of Mechanical and Aerospace Engineering says their results point to a previously undefined mechanism where ‘mechanotransductory signalling’ can be harnessed using microtopographies for future clinical settings. “Harnessing surface microtopography instead of biological factor supplementation to direct cell fate has far-reaching ramifications for smart cell cultureware in stem cell technologies and cell therapy, as well as for the design of smart implant materials with enhanced osteo-inductive capacity,” Dr Cadarso said.

The findings were published in Advanced Science.

Source: https://www.monash.edu/

How To Stimulate Broken Bone Cells To Heal Much More Quickly

It was just a couple of months ago that we heard about an implantable material that electrically stimulates bone cells, causing them to reproduce. Now, scientists have created a similar substance that utilizes magnetism. There are already a number of experimental materials that have a three-dimensional scaffolding-like microstructure, which simulates the structure of natural bone. After a piece of such a material has been implanted at a bone wound site, cells from the body’s adjacent bone tissue gradually migrate into it. Those cells reproduce over time, while the scaffolding simultaneously dissolves. Eventually, all that’s left is newly-grown bone, in the shape and location of the implant.

One of the challenges of the technology involves getting the bone cells to migrate and reproduce quickly. Although growth-boosting chemicals are often added to the material, scientists at the University of Connecticut took another approach with a scaffolding that they announced this June – it generates a weak electrical field in response to externally applied ultrasound pulses, and that field in turn prompts the bone cells to reproduce.

More recently, though, a team at Spain’s University of the Basque Country developed a material that instead incorporates magnetic nanoparticles. These are dispersed within a 3D matrix of a biocompatible silk-derived protein known as fibroin.

When we apply a magnetic field, we bring about a response by these nanoparticles, which vibrate and thus deform the structure, they stretch it and transmit the mechanical stress to the cells,” says the lead scientist, Dr. José Luis Vilas-Vilela. In in vitro lab tests, that stress stimulated bone cells to reproduce much more quickly than would have otherwise been the case. In fact, the technology could conceivably be used to regrow more than just bone.

We are developing various types of materials, stimuli and processes so that we can have the means to achieve the regeneration of different tissue,” says Vilas-Vilela. “In addition, the idea would be to use the stem cells of the patients themselves and be capable of differentiating them towards the type of cell we want to form the tissue with, be it bone, muscle, heart or whatever might be needed.”

The research – which also involved scientists from Portugal’s University of Minho and biotech firm BCMaterials – is described in a paper that was recently published in the journal Materialia.

Source: https://www.sciencedirect.com/
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