regenerationman-blog

[regenerationman-blog]

Elastic Bones

Being under the knife of a skilled surgeon is one reality of a serious bone shattering injury, requiring many special medical tools. What if, in future operations, these special tools were replaced with a 3D printer and some unique ink? This is what researchers at Northwestern University have predicted with the creation of what they call hyperelastic bone, a 3D printable scaffold made possible by the enormous advancements in 3D printing technology over the past decade. Allowing for applications in regenerative medicine. However, you may think to yourself “don’t broken bones regenerate themself?” Yes, this is true although in some cases where bones are too damaged or completely missing we need to replace the bone to allow for regeneration to happen. This is known as bone grafting and uses natural or synthetic bone, like hyperelastic bone, to replace the previous bone.

Hyperelastic bone is not the first synthetic bone scaffold to be created for grafting. Current methods include the use of ceramics made out of minerals similar to natural bone. However, there are a slurry of problem with these material. One is the difficulty in surgical implementations because of its stiffness. Making it difficult for surgeons to manipulate it into confined spaces. Other limitations include its high cost and often rejections by the immune system.

Another option that is preferred by many surgeons is using natural bone from the patient’s own body called autografts. This is preferred because of the natural scaffold it contains and other natural growth factors and cells. Also the new bone is from the patient’s own body, therefore no risk of immune rejection. But this requires another surgery to gravest this bone, creating longer recover times. Additionally, one person only has so much bone that is safe to relocate, putting a restraint on the size of bone being used.

What if there was a way to keep the natural ability of a scaffold to promote regeneration while at the same time be easily manipulated and produced?

Thankfully, researchers at Northwestern University in Illinois are working on a material to do just that. As mentioned above they call this material hyperelastic bone, which is made up of a naturally occurring mineral in bone called hydroxyapatite, a biodegradable polymer called polycaprolactone, and a solvent. Hydroxyapatite adds strength and allows stem cells to start proliferating to form bone. Polycaprolactone adds flexibility to the material and the solvent allows for the material to be a liquid but as it evaporates it allows the layers to stick to each other. Therefor this material is ideal for 3D printing technology. When in liquid form it is placed into ink cartridges and than printed into layers to form any shape or object imaginable. This allows for the construction of simple sheets to large and oddly shaped structures resembling bones in the body like the spinal bones. 

What makes hyperelastic bone better than other materials is its user-friendly construct, which I’m sure surgeons will appreciate. Due to its 3D printability they can easily take an x-ray of the patients bone to be replaced, enter this data into a computer and press print, and within a day the object can be created. This created patient specific molds that are easily personalized. Another plus is the materials flexibility allowing the surgeon to manually manipulate the bone mold to squeeze into tight spots for a perfect fit, and bounce back to its original shape (figure 1). Its ease of use and production make this cheep and readily available, almost as easy as purchasing a regular printing cartridge at a stationary store.

Figure 1 – Elasticity of hyperelastic bone under the force of a hydraulic press. A) Initial shape of hyperelastic bone before compressed. B) Compressed hyperelastic bone. C) Reformation of the initial shape of hyperelastic bone after compression.

Like other previously created scaffolds hyperelastic bone works in a similar way to regenerate large portions of bone. It supposedly works by acting as a scaffold to lay down the foundation for stem cells migrate into. Once in place the stem cells proliferate and transform into new bone tissue within the new material. As these new tissues form the synthetic scaffold is integrated into the new bone and eventually breaks down to be recycled, as all normal bone tissue does.

To test their predictions these researchers preformed animal studies to test hyperelastic bones ability to support cell proliferation and integration into the animal’s natural bone. One interesting test done on a macaque monkey, which resembles humans more than using rats, used hyperelastic bone to replace a region of damaged skull. Only 4 weeks after the surgery the hyperelastic bone scaffold was filled with new tissue including blood vessels, which are needed to support new bone tissue formation, and some calcified bone (figure 2). Additionally, they did not notice any adverse effects to the monkey such as immune rejection or infection, which is very common in other synthetic scaffolds.

Figure 2 – Animal surgery using hyperelastic bone to replace damaged skull bone in macaque monkey. A) Replacement of damaged skull bone with hyperelastic bone. B) Results after a 4 week recovery post replacement surgery. C) Zoom in of the surgically replaced bone after the 4 week recovery.

As the title of their report suggests “Hyperelastic “bone”: A highly versatile, growth factor–free, osteoregenerative, scalable, and surgically friendly biomaterial”, they claim it is a growth factor-free biomaterial for regeneration. But, bone regenerates on its own without the help of added growth factors, as long as it has a scaffold, so that is an unnecessary claim. Additional to this, in one of the animal studies fusing the backbone of rats using hyperelastic bone, they added a growth factor with hyperelastic bone to further enhance bone formation. This is contradictory to their claims of growth factor-free material. However, results did show hyperelastic bone, on its own, inducing and supporting bone formation. They should have either left the growth factor-free claim out or not included this data.

There are roughly 4 million bone grafting surgeries annually in North America. Requiring large amounts of grafting material making this a multibillion-dollar industry. Its no surprise that enormous amounts of research are being done innovate this field, such as hyperelastic bone. However, you must stay skeptical about some claims until further support is uncovers. Such as the animal trial on the monkey that was only done on one monkey. A larger sample size is needed to support their clams in order to be implemented in humans. Although, I feel these results will be easy to obtain and will hopefully show the same promising results. 

In the future, the reality of a bone shattering injury will be less drastic and a lot easier for the surgeon, who will now be alongside a skilled 3D printing specialist.

[regenerationman-blog]

Scarless Wounds

When your body is deliberately or accidentally cut open, and produces a gaping wound, your first reaction is “ouch!” However your second reaction is “that’s going to leave a scar”. Scars are the product of natural wound regeneration in humans. They are formed by cells called fibroblasts, which secrete a fibrous protein called collagen into the wound to support the regeneration of damaged tissue. But the amount of collagen they secrete is so numerous that regenerating cells do not have space to regrow and therefore forms a fibrous tissue called scar tissue. That means that some cells are excluded from the tissue giving it an abnormal appearance, these include fat cells, hair follicles and sweat glands.

Of course, this abnormal tissue is not desirable and research around its removal/prevention is a multi million-dollar industry. However, there are little to no scar removal/prevention treatments available. However, research at the University of Pennsylvania’s Perelman School of Medicine thinks they have discovered a new preventative method for regenerating normal skin tissue rather than scar tissue in mice. Their unique approach involves the formation of hair follicles in the wound that will stimulate the formation of fat cells, which is characteristic of normal skin. This works by using techniques previously known to stimulate hair follicle formation. Once the hair follicle is formed it induces myofibroblasts, a class of fibroblasts found mostly in wounds, to differentiate into fat cells. This is thought to be due to the activation of an embryonic pathway, bone morphogenetic protein (BMP) signaling, causing epigenetic changes to DNA and remodeling transcription. The exact mechanism is unknown but the results, of reduced scar tissue, are very promising.

This approach allowed for the formation of cells, fat cells and hair follicles, that are not present in scar tissue, and therefore gives the new tissue a normal appearance. If this research becomes mainstream, the next time you get a huge cut your second reaction will be “that would have left a scar” but unfortunately your first reaction will stay the same. 

[regenerationman-blog]

This post relates to my share a post on the Ted Talk on Andrew Pelling and his idea of using apples as a scaffold for human organs. He stressed the fact of how easy and cheap this would be if we could harness the ability to do it yourself at home. At the end of his talk he posted a DIY on how to create an apple scaffolds for organs. 

With the DIY guide and his video as inspiration I thought it would be interesting to create a mold of my ear from an apple. I didn’t have the reagents to do the decellularization protocol. However, I did try my best to scalp my ear out of the apple. It was a lot harder than anticipated and took a few more trips to the grocery store. The upside is now I have practice creating my own ear, if this technology takes off and I lose my ear.

I hope you enjoy my results.

No apples were wasted in the production of this post.

[regenerationman-blog]

Organs Need Blood!

The rapid development among research in regenerative medicine is revolutionizing the way to view organ transplants, and is improving the ability to repair and replace human tissue. One of the latest improvements is allowing us to solve the issue regarding organ failure, which is a leading healthcare challenge in the western world. There are approximately 6,000 people waiting for an organ transplant in Canada today, and there are an increasingly low number of donors to keep up with the high demand, therefore we must resort to other sources such as lab-grown organs. Although lab-grown organs are an efficient alternative, they are challenging to create, and even more challenging to maintain in the body. However, recently researchers at the University of Bath have discovered a potential method of keeping lab-grown organs alive and accepted into the body. This involves the use of the patient’s own blood in which creates a vascular network around the new lab-grown organ.

Creating lab-grown organs and tissues for transplant into patients is a priority in medicine and researchers in regenerative medicine are getting close to unlocking this potential. However, all this research is useless if we cannot get the body to accept the transplant and allow it to grow. These problems are a major challenge, and to solve them we need to figure out a way to provide new organs with a network of blood vessels that connects to the patients vascular system. This will allow the organs to survive and integrate into the recipient seamlessly.

Other methods previously used to overcome this problem involve the use of animal-derived hormones to stimulate vascularization. Using animal-derived hormones only have the capacity to form minimal capillary like structures and not actual vascular networks, which makes the organs less likely to survive when transplanted.  Additionally, since this method uses animal derived products this makes it harder for approval of clinical trials due to the risk of animal disease transmission and increases the likelihood of rejection by the patient.

A study done by researchers at the University of Bath, in the United Kingdom, have discovered a different way to stimulate blood vessel formation and their approach relies on the use of two materials. The first is human platelet lysate gel (hPLG), which is the extracellular matrix from human platelet cells used as a 3D scaffold to support the proliferation and vascularization of tissues. The other material is endothelial progenitor cells (EPCs), which are a type of stem cell that helps maintain blood vessel walls by regenerating into the endothelial lining of blood vessels. It is important that both of these materials are isolated from the patient to avoid rejection by the immune system. Meaning that when the organ is introduced into the body it is not recognized as foreign and makes it easier for the body to accept it.

EPCs grow and differentiate into the endothelial cells lining blood vessels, and when these researchers placed them in a 3D capsule of hPLG this caused the formation of a capillary vascular network. To create hPLG they extract blood from a patient, purify platelets, and sonicate to lyse them. Next they add a protease thrombin to cleave the lysate and form the gel (figure 1). Additionally they wanted to see if this method could create a vascular network around organs. To do this they used a cross section of a mouse aorta and placed it in the hPLG 3D capsule and allowed it to incubate for 3 days at body temperature (figure 1). Interestingly, this caused high amounts of capillary’s sprouting from the aortic ring.

Figure 1 – Process of creating human platelet lysate gel (hPLG) used for blood vessel formation of mouse aorta section with endothelial progenitor cells (EPC). A) Extraction of blood and purify platelet cells. B) Sonication of platelet cells to lyse them. C) Addition of thrombin to make hPLG then add EPCs and mouse aorta section. D) Blood vessel formation around mouse aorta ring section after 3 days.

The ability of hPLG to support the formation of vascular capillaries by EPCs has never been studied, prior to this, and is ideal for creating vascular networks for organs. New work is being done to test hPLG/EPCs success in other tissues and eventually lead to clinical trials.

The basis for their idea came from an earlier study that use platelet lysate liquid from patients, and showed to be a natural reservoir for growth factors to promote tissue repair, including blood vessel formation. These researches used the platelet lysate liquid as the media for EPCs to grow. However, the results from that did not show any significant blood vessel formation or proliferation of EPCs. From these results the researchers at Bath reasoned it would be useful to create a natural scaffold in order for EPCs to develop into blood vessels. They did this by turning the platelet lysate liquid into a 3D gel using the natural protease thrombin.

Next the researchers at Bath looked into how hPLG causes increase proliferation and blood vessel formation in EPCs. They discovered there are many growth factors released from platelets, one with importance is known to stimulate blood vessel formation in vivo and is known as vascular endothelial growth factor (VEGF). This growth factor interacts with the VEGF receptor (VEGFR2) on the EPCs and using an inhibitor against VEGFR2 to block its affect, it was pinpointed as the underlying signal that causes the response. However, they could not uncover the whole pathway on how it causes increases blood vessel formation and proliferation. They hypothesize that the 3D scaffold created by the hPLG extracellular matrix orients the receptors on EPCs in a way that increases their sensitivity to VEGF and causing blood vessel formation through activation of transcription factors (figure 2).

Figure 2 – Predicted signaling transduction pathway of vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) causing cell proliferation and blood vessel formation.

Using hPLG they are able to deliver growth factors where needed and induce more efficient formation of capillary vascular networks. This will increase the nourishment to the organ and increase its likeliness of survival.

The beauty of this new approach is that components of a person's own blood could be manipulated to create a scaffold for new blood vessels. This increases the likelihood that the new tissue will be integrated into the patient's body. However, additional research is needed to support this, and if proven successful, could improve the lives of many people by being able to engineering organs equipped with a functional vascular network. Maybe one day we will no longer need to rely on the organs we are born with and will look back on this study in history as the stepping-stone responsible for creating viable lab-grown organs.

[regenerationman-blog]

Regenerative Dentistry?

Regenerative medicine is a continuously evolving field, and recently has adopted a new branch of medicine, involving applications in dentistry. These applications include the regeneration and repair of teeth, naturally, without using synthetic materials. Cavities (dentil caries), which I’m sure some of you have had as a child, require dentists to inject synthetic material like inorganic minerals to fill it and prevent infection. However, they do not regenerate the tooth and only acts like a plug, which often needs to be redone. Researchers in England at King’s Collage London came up with a way to combat this by stimulating natural repair to heal damaged teeth.

In this study researchers created a way to regenerate dentine in mice, to seal holes drilled in by the researcher. They used an already clinically approved collagen sponge to soak up and slowly deliver a small molecule to the underlying dental pulp to stimulate regeneration. This small molecule is Tideglusib, currently in clinical trials as an Alzheimer’s treatment, and acts as a glycogen synthase kinase (GSK) inhibitor. GSK is a kinase involved in the Wnt signaling pathway and when inhibited allows the transcription of genes needed for regeneration. Results from their experiment with mice showed nearly complete reformation of dentine and importantly it replacing the biodegradable sponge. Using this sponge is what makes this different from any other treatment because it is able to get replaced by the natural tissues to fully seal the hole.

Although this approach is very new, it has advantages that will allow it to fast track into practice. These are that it uses a clinically approved sponge and miniscule amounts of Tideglusib, which is already in clinical trials. So maybe someday in the near future your children’s cavities wont be filled, they will be regenerated.

[regenerationman-blog]

I love ted talks and I came across this one that I thought fit nicely with my topic of tissue regeneration. It’s a very new and undeveloped idea that uses cellulose scaffold as the building block for tissue repair. Using scaffolds from other organisms to stimulate growth is very similar to methods of regeneration today and this idea may lead to new innovations. 

I think Andrew does an excellent job presenting his idea and I really think it is worth a watch. Also there is another weird and wonderful idea he came up with, but ill let you watch it and see it for yourself. (Hint: it involves asparagus!)

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The paper he published on this can be found here.

[regenerationman-blog]

About me!

Hello everyone!

My name is Joel McLeod and I am in my fourth and final year of my biochemistry degree ant UNB. I was born and raised in the small town of St. Stephen NB where I learned that the good thing about living in a small town is that everyone knows each other, however, the bad thing about living in a small town is that everyone knows each other (haha). In all seriousness that town left its mark on me and without it I wouldn’t be who I am today, which brings me to who I am today.

I love all competitive sports but my first love is football. Another activity I am very passionate about is hunting and fishing. I think about it all the time and I cant accurately explain why I like it. Maybe it’s because of the adrenalin rush I get or the prize I get after? You will only truly understand what I mean if you experience it. A big part that goes with hunting is preparing the animal for consumption. This takes delicate and fast work and this is what assured me that I had the stomach to peruse a medical profession.

Small mouth bass caught (and released) in Chamcook lake summer 2016.

I grew up in a family that has a lot of health professional so naturally I was drawn to it. I have wanted to become a physician for as long as I can recall because I get enjoyment out of helping people and am fascinated with how the body works. This interest is what lead me to my blog topic.

My blog is centered on the topic of wound repair using regenerative medicine. This is an expanding and exiting topic that uses the approach of adding biological polymers to stimulate tissue repair to speed up the process and/or grow tissue back that wouldn’t have without it. This could mean the difference between walking again or not!

Tissue regeneration is something that I am very exited about because of my interest in health care and medicine. It is relevant to all of us because eventually we all will have some sort of wound that needs to be fixed, even if some are more sever than others. This research allows us to better our health care and our ability to recover from devastating injuries. This research is developing every year and shows promising results for future growth.

I will be uncovering new cutting edge research about this topic throughout the semester and I hope that you will enjoy and be as fascinated as I am.