Tag: university of ottawa

The Future is Weird: Human Urine used to grow Teeth?!

3dstemcellsStem cell research has been expanding impressively in recent years, and the range of applications has been growing accordingly. And while all are impressive and useful, some are – admittedly – odd and even a tad gross. One such application is the one that was recently unveiled in China, where a team of biologists are using stem cells harvested from human urine to grow structures in mice that resemble teeth.

The team, led by Duanqing Pei and Jinglei Cai from the Guangzhou Institute of Biomedicine and Health, had announced back in 2011 that it had successfully reprogrammed skin-like cells from the kidneys, found in urine, to turn into pluripotent stem (iPS) cells. As researchers have known for some time, these iPS cells can be tweaked to become pretty much any human cell in the body.

tooth-from-urine-cell-regenerationIn a paper produced by the Guangzhou biomedical team – which appeared in the peer-reviewed, open access journal Cell Regeneration last week – they claim the ability to “regenerate teeth with patients’ own cells” is an “ideal solution” to the loss of teeth through accidents or disease. As just one of many applications of stem cell research, the aim is to create synthetic biological tissues that can replace artificial implants.

Once the cell sheets formed into epithelial tissue – the kind of cells found in human skin and teeth – they implanted them with tissue from the jaw of a mouse embryo (to encourage it to grow into a tooth) in the kidney of a mouse. Three weeks later, they noted that the human tissue had turned into cells called ameloblasts that secrete enamel, the hard, bone-like substance on the outside of the tooth.

urine_stemcells_teethThe result was a series of tooth-like structures which possessed the hardness “found in the regular human tooth”, which were then harvested. Assuming that this approach could be scaled to involve dozens of mice across thousands of labs, artificial teeth could be mass produced and then be made available to dental clinics all over the world.

However, the real innovation came with the new method that the research team devised to get around some flaws in the traditional method. This method, which involves inserting the stem cells into blanket cells via a genetically engineered retrovirus, can lead to a destabilization of the cell genome, rendering the tissue unpredictable, susceptible to mutations and thus a liability.

stem_cells1Hence why Pei and his team opted for another route, one which they claim presents a safer, faster alternative. Having extracted kidney epithelial cells from the urine of three donors, the team used vectors — a type of DNA molecule useful in transporting genetic information from cell to cell. This allowed them to transport the genetic information without having to integrate the new genes into the chromosome of the kidney cell.

According to their paper, this process may be partly responsible for the aforementioned mutations in the first place. And once they tested out their new process, it took only 12 days for the pluripotent stem cells to form in a petri dish – roughly half the time it takes using the traditional approach.

URINE-STEM-CELLS-TEETH-570William Stanford – a University of Ottawa researcher who holds a Canada Research Chair in integrative stem cell biology – indicated that their approach is not entirely now. Growing various kinds of human tissues inside a mouse kidney is a common technique used by stem cell biologists, Stanford said. In the course of doing so, researchers will occasionally grow what looks like teeth by accident.

However, the Guangzhou team have modified the technique to grow teeth intentionally. And their approach is an improvement in that it does not require skin samples to be harvested by the human subject (a common practice at the moment). Using urine-harvested stem cells only requires that they pee into a cup, and the turnaround time is a matter of weeks instead of months.

Good news for anyone who is missing some chomper, or feels self-conscious about crooked or chipped teeth and can’t afford those expensive, porcelain implants. What’s more, teeth are really just the tip of the iceberg. In time, other organic tissues could be grown as well, allowing for further developments in the already exciting field artificial organ generation.

Sources: cbc.ca, wired.com

Ending Cancer: “Computational Cell Biology”

Cancer-researcherOne doesn’t think that diseases themselves would be vulnerable to infections; in fact, it seems counter-intuitive at best. And yet, that is what a group of scientists from Ottawa, Ontario (my old hometown) are proposing. Using and advanced mathematical modeling system to engineer viruses that will infect and destroy cancer cells, the team has been investigating how treatment techniques and genetic modification might allow cancer-killing (oncolytic) viruses to overcome cancer cells’ anti-infection defenses and kill them.

In a report filed with Nature Communication magazine, the lead authors – Dr. Mads Kaern and Dr. John Bell, a medical researcher and senior biologist from the University of Ottawa – detailed how the team used mathematical modeling to create techniques to render cancer cells highly vulnerable to infection while leaving healthy tissue untouched. The modified oncolytics zero in on the very thing that makes cancer cells so destructive — their potential to proliferate and grow explosively and unchecked, and blocks it.

dnacomputingCancer cells and normal cells are equipped with defensive mechanisms that protect them from invading cells. By using mathematical models, the Ottawa team has managed to equip oncolytic viruses with a gene that helps them override many kinds of cancer cells’ natural defenses, slowing the cancer’s reproduction and also making it more vulnerable to other infections.

Kaern and Bell constructed a mathematical model of the process of infection of a cancer cell, including how the virus would replicate, spread itself and override the cancer’s biological defenses. The study used predictive models to understand how the viruses might better overcome the cancer’s defenses, models that turned out to be surprisingly accurate.

cancer_cellIn an interview with Raw Story, Kaern explained the process and how it works:

These viruses tend to replicate better in cancer cells, because cancer cells tend to grow and divide more with an increased metabolism. The viruses are sort of exploiting that by replicating more aggressively, specifically in cancer cells.

The trick, Kaern said, is to engineer viruses that do that, but with minimal harm to surrounding healthy cells. The engineered viruses are built to not propagate in healthy tissues. But when it comes to cancer cells, it only takes one oncolytic virus making contact with one cancer cell to begin the propagation process.

chemotherapy2The benefits of this kind of treatment are obvious and profound. In addition to being self-propagating, it will also eliminate the need for expensive and unhealthy treatment:

You don’t really have to overload the system with tons of chemotherapy, which also targets specific cancers, right? But you have to ingest these large amounts intravenously and people get really sick from that because all the cells in the body are affected. So the advantage of the viruses is that they will find where they have to go and you only need one to start to process.

Of course, their is still a great deal to learn though. As Kaern points out, “cancer is a very complicated and diverse disease, and some viruses work well in some circumstances and not well in others.” While a “magic bullet” anti-cancer panacea is probably not going to arise in the near future, the use of mathematical modeling is speeding up the research process and opening up exciting possibilities.

Source: rawstory.com