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5 posts from July 2009

July 31, 2009

A new model to expand blood stem cells

In a Molecular Systems Biology paper released this week, our team at the University of Toronto revealed a new mathematical model that links functional cellular assays to specific model outputs, defines cell-level kinetic parameters such as cell cycle rates and self-renewal probabilities as functions of culture variables, and simulates feedback regulation using cell–cell interaction networks. In lay terms, we created a model that can explain communication between cells, specifically cells that control the growth of blood cells.  

The goal of our study was to understand what regulated human blood stem cell growth outside of the body. Blood stem cell transplantation is used to treat and cure genetic blood diseases, such as anemia, and blood cancers, like leukemia and lymphoma. Usually, the more blood stem cells you have to transplant, the better the outcome. But while there is great demand, there is not a large supply, primarily because it is so hard to grow blood stem cells in vitro. Scientists have been working for years to expand these cells, but nobody has yet been able to find a robust and reliable method.

In the human body, cells talk to each other using secreted factors. Sometimes they send messages that encourage cell growth and sometimes they send messages that disrupt cell growth.  Our model provides a formal framework to try to understand the codes that cells use in this communication system.  We tested our model predictions by culturing umbilical cord blood stem cells and measured the effects of specific manipulations on blood stem and progenitors cell output. We found that we could influence communication between cells, disrupting cellular cross-talk that hindered growth and encouraging cross-talk that stimulated growth. Our model is a useful tool to simulate blood culture outputs and to test, in silico (in computer simulations), new ideas about how to improve blood stem cell growth. We've applied this model to cell cultures in various configurations, and also expanded it to provide insight how blood stem cells may be regulated in humans under normal and abnormal conditions, such as in patients with leukemia

Using our model, we can use a computer to predict conditions for enhanced blood stem cell growth outside of the body.  This should contribute towards efforts to generate a greater supply of blood stem cells for transplantation, which would greatly impact the hundreds of thousands of people suffering from blood diseases and cancers around the world.

-- Peter Zandstra and Daniel Kirouac, University of Toronto

Canadian stem cell researchers Eaves and Dick to receive hematology awards

The American Society of Hematology recently announced six award recipients to be honoured for their outstanding scientific contributions in the field of hematology. Among the distinguished scientists who are to receive awards are two Canadians – Connie Eaves and John Dick – both of whom are Stem Cell Network researchers.

I am very proud of Connie and John, who as leading stem cell researchers have made extremely important contributions to our understanding of stem cell biology and its implications for disease. Their virtuosity and scientific insights have both advanced our knowledge and provided new paradigms for understanding and fighting disease. They show us why Canada continues to be one of the world’s most respected and desired places to conduct stem cell research. As a colleague and friend, I congratulate them both on this achievement – one of many yet to come.

View the summaries from the American Society of Hematology website:

Connie Eaves, PhD
, of the BC Cancer Agency, University of British Columbia in Vancouver, will be presented with the Henry M. Stratton Medal, which honors an individual whose well-recognized contributions to hematology have taken place over a period of several years. Dr. Eaves will receive this award for her remarkable achievements in the area of stem cell biology for more than two decades. Dr. Eaves has been on the cutting edge of adapting or introducing technologies related to stem cell biology, especially her ground-breaking techniques of using the long-term culture system as means of understanding the proliferative and renewal properties of normal and malignant primitive human hematopoietic stem cells.

John E. Dick, PhD, of the University Health Network in Toronto, will be recognized with the E. Donnall Thomas Lecture and Prize for his pioneering research into the development of human leukemia, which has transformed the view of how leukemia progresses. This prize, named after a Nobel Prize laureate and past Society president, recognizes pioneering research achievements in hematology.

July 29, 2009

Mending broken hearts

Cardiovascular disease accounts for the death of more Canadians than any other disease, more than 72,000 people each year. There is currently no cure for heart failure, and goals for treatment have always been to improve symptoms, stop the condition from getting worse, and prolong life span.

But results from recent stem cell trials point to potential new treatments, and the possibility of growing new heart tissue. Research being conducted around the globe has many scientists now believing that cellular therapy will revolutionize approaches to heart failure: instead of being palliative and simply trying to alleviate symptoms, scientists may be able to regenerate healthy heart muscle and repair damaged hearts

A complete summary of heart failure has just been added to the For Patients section of the Stem Cell Network's website. This new page includes information on the causes, effects and current treatments, as well as recent research and clinical trials.

July 24, 2009

Updates on MS, stroke, spinal cord injury and more

SCN lab stock

New research in the area of regenerative medicine is coming out regularly.  Here are some recent examples:

  • Researchers in Toronto and Saskatchewan are looking at cells found in human skin, inside the nose and in the spinal cord as autologous sources of myelinating cells to treat multiple sclerosis.
  • A UK company called ReNeuron is starting clinical trials in Glasgow, Scotland to treat stroke.  They will give patients using a therapeutic dose (about 20 millions cells) of genetically-modified human embryonic stem cells.  These cells will “activate repair pathways” to stimulate new blood vessels and brain cells.
  • Researchers in Colorado and New York are developing an approach to treating spinal cord injury, focusing on astrocytes. Astrocytes are important in generating nerve fibre growth in early development of the nervous system. By manipulating different growth factors researchers have had dramatic outcomes when they injected these cells into the injured spinal cords of rats. This approach is now being developed for clinical trials.

Read more about current research in the updated disease sections in the For Patients section on the Stem Cell Network website. Information has been added for eye disease, spinal cord injury, multiple sclerosis, stroke and Parkinson's. There are also new supplemental resource links for many of the areas.

July 13, 2009

ISSCR 2009: outside the plenary hall

Cel-lules mare - The night before ISSCR's 7th Annual Meeting officially began, a public symposium was held at CosmoCaixa Barcelona in the north end of the city.  The event was open to everyone attending ISSCR as well as curious members of the Spanish public.

The evening started with ESTOOLS' "Smile of a Stem Cell" photo exhibition, a collection of stem cell pictures taken and captioned by scientists working across Europe. The exhibit has been shown all over the continent at high schools, galleries and even prisons. Sebastien Duprat, the Training and Outreach Manager at ESTOOLS, wanted the traveling exhibition to be a stem cell event that anyone could feel comfortable attending, and he has seen it spark public discussion and start to bridge the gap between scientists and the public. Duprat's 2009 Stem Cell Research article provides a summary of the project and its approach.

The symposium also included films and a panel discussion.  EuroStemCell and EuroSystem screened their award-winning short film "A Stem Cell Story," followed by the newest film in the series, a short overview of iPS cells by C.Clare Blackburn.

The panel of nine included scientists, heads of international stem cell agencies, ethicists and documentary filmmakers.  In a lengthy Q&A session, they tackled a range of issues, from how to communicate with the public to sources of stem cells, IP rights and clinical trials. Fiona Watt, past ISSCR president, in speaking about stem cell tourism, commented that ISSCR is "very concerned about this issue" and informed the crowd that the Society is working to both alert the public to specific unproven therapies and to create a new fact sheet that will provide a list of questions patients can ask a clinic to help assess the validity of the clinic's claims.

ICSCN meetings - As in previous years, members of the International Consortium of Stem Cell Networks used the ISSCR event as the backdrop for the annual gathering of Consortium members, currently numbering 19 and representing regions around the world. In two meetings, the ICSCN heard summaries of activities from each member network and planned activities for the upcoming year. These include a continuation of travel grants and sponsorships to allow trainees to attend workshops and conferences held by other ICSCN members outside their own country, organization of a second post-doc workshop at the ISSCR 2010 meeting, and a concerted effort to foster increased collaboration between international labs working in specific disease areas.