Stem Cells

First are the videos from today’s presentation:

After watching these videos go back to your notes and re-answer the questions from the “THINK!” section on another piece of paper. Then write a paragraph detailing the pros and cons of stem cell use and decide whether you are for or against their use and why (use evidence to explain why).

Chemical Guided Missile Could Be the Answer to Wiping out Cancer

RNA Aptamer

ScienceDaily (Feb. 18, 2011) — Deakin University medical scientists have created the world’s first cancer stem cell-targeting chemical missile, placing them a step closer to creating a medical ‘smart bomb’ that would seek out and eradicate the root of cancer cells.

The Deakin researchers have worked with scientists in India and Australia to create the world’s first RNA aptamer, a chemical antibody that acts like a guided missile to seek out and bind only to cancer stem cells. The aptamer has the potential to deliver drugs directly to the stem cells (the root of cancer cells) and also to be used to develop a more effective cancer imaging system for early detection of the disease. Their discoveries have been published recently in an international cancer research journal, Cancer Science.

The Director of Deakin Medical School’s Nanomedicine Program, Professor Wei Duan, said the development of the aptamer had huge implications for the way cancer is detected and treated.

“Despite technological and medical advances, the survival rates for many cancers remain poor, due partly to the inability to detect cancer early and then provide targeted treatment,” Professor Duan said.

“Current cancer treatments destroy the cells that form the bulk of the tumour, but are largely ineffective against the root of the cancer, the cancer stem cells. This suggests that in order to provide a cure for cancer we must accurately detect and eliminate the cancer stem cells.”

The aptamer is the first part of the ‘medical smart bomb’ the researchers have been developing.

“What we have created is the ‘guided missile’ part of the ‘smart bomb’,” Professor Duan explained.

“The aptamer acts like a guided missile, targeting the tumour and binding to the root of the cancer.

“The aim now is to combine the aptamer with the ‘bomb’ (a microscopic fat particle) that can carry anti-cancer drugs or diagnostic imaging agents directly to the cancer stem cells, creating the ultimate medical smart bomb.”

Professor Duan said the medical smart bomb opened up exciting possibilities for detection and treatment of cancer.

“The cancer stem cell-targeting missile and the smart bomb could revolutionise the way cancer is diagnosed,” he explained.

“The minute size of the aptamer means it could locate cancer cells in their very early stages. Attaching radioactive compounds to the aptamer could lead to the development of sensitive diagnostic scans for earlier detection, more accurate pinpointing of the location of cancer, better prediction of the chance of cure and improved monitoring of the response to treatment.

“More accurate identification of the type of cancer present would lead to more personalised treatment that is more successful and cost-effective.

“This could ultimately lead to better cancer survival rates and greatly improved quality of life for patients.”

More about the project

The project is a collaboration between Deakin University’s School of Medicine and Institute for Technology Research and Innovation and the Indian Institute of Science in Bangalore, Institute of Life Science along with Barwon Health’s Andrew Love Cancer Centre and ChemGenex Pharmaceuticals. It has received $700,000 funding from the Federal Government’s Australia-India Strategic Research Fund, with reciprocal support from the Indian Government.

Cancer cells are made up of many cells that have different characteristics. They are, for example, like a tree with some cells being the root system and the others the branches and leaves; if you cut off the branches and leaves, the root of the tree is still alive. Current cancer treatments are ineffective in eradicating the whole cancer cell because they only kill the branches and leaves. The root cells are particularly tough and resistant to drugs and radiotherapy. They possess drug pumps that pumps out the anti-cancer drugs. This means that, while most of the cancer cell is killed, the cancer root remains and can regenerate. This makes the root cells (cancer stem cells) an important target for new cancer treatments.

There are two parts to the project being undertaken by the Deakin and Indian scientists.

The first is building the guided missile, or aptamer. The aptamer is a chemical antibody, much smaller and cheaper and easier to make than conventional antibodies, designed to bind specifically to cancer cells. It has been designed to effectively penetrate a tumour and specifically target cancer stem cells. This missile will carry the ‘bomb’; the second part of the drug delivery system.

The ‘bomb’ will be a very smart lipid, or fat particle that will remain stable in the body, i.e. it will not break down. This particle will carry the anti-cancer drug as well as anti-cancer genes.

When combined, the ‘smart bomb’ will be injected into the body and find the cancer cell. It will then enter the cell through an endosome route — a small road within the cell. Once inside the cell, it will very quickly release its contents and kill the whole cancer cell.

A unique part of the system being developed is that the bomb is very stable outside of the cancer cell, but once inside it will very quickly release its contents and kill the cancer cell from within. This system is made by materials that are very human compatible and human degradable — it is not toxic to other cells in the body and would cause very limited side-effects.

Stem cells reverse blindness caused by chemical burns

Stem cells reverse blindness caused by chemical burns
Posted 6/24/2010 12:01 PM
By Alicia Chang, Associated Press

LOS ANGELES — Dozens of people who were blinded or otherwise suffered severe eye damage when they were splashed with caustic chemicals had their sight restored with transplants of their own stem cells — a stunning success for the burgeoning cell-therapy field, Italian researchers reported Wednesday.

The treatment worked completely in 82 of 107 eyes and partially in 14 others, with benefits lasting up to a decade so far. One man whose eyes were severely damaged more than 60 years ago now has near-normal vision.

“This is a roaring success,” said ophthalmologist Dr. Ivan Schwab of the University of California, Davis, who had no role in the study — the longest and largest of its kind.

Stem cell transplants offer hope to the thousands of people worldwide every year who suffer chemical burns on their corneas from heavy-duty cleansers or other substances at work or at home.

The approach would not help people with damage to the optic nerve or macular degeneration, which involves the retina. Nor would it work in people who are completely blind in both eyes, because doctors need at least some healthy tissue that they can transplant.

In the study, published online by the New England Journal of Medicine, researchers took a small number of stem cells from a patient’s healthy eye, multiplied them in the lab and placed them into the burned eye, where they were able to grow new
corneal tissue to replace what had been damaged. Since the stem cells are from their own bodies, the patients do not need to take anti-rejection drugs.

Adult stem cells have been used for decades to cure blood cancers such as leukemia and diseases like sickle cell anemia. But fixing a problem like damaged eyes is a relatively new use.

Researchers have been studying cell therapy for a host of other diseases, including diabetes and heart failure, with limited success.

Adult stem cells, which are found around the body, are different from embryonic stem cells, which come from human embryos and have stirred ethical concerns because removing the cells requires destroying the embryos.

Currently, people with eye burns can get an artificial cornea, a procedure that carries such complications as infection and glaucoma, or they can receive a transplant using stem cells from a cadaver, but that requires taking drugs to prevent rejection.

The Italian study involved 106 patients treated between 1998 and 2007. Most had extensive damage in one eye, and some had such limited vision that they could only sense light, count fingers or perceive hand motions. Many had been blind for years and had unsuccessful operations to restore their vision.

The cells were taken from the limbus, the rim around the cornea, the clear window that covers the colored part of the eye. In a normal eye, stem cells in the limbus are like factories, churning out new cells to replace dead corneal cells. When an injury
kills off the stem cells, scar tissue forms over the cornea, clouding vision and causing blindness.

In the Italian study, the doctors removed scar tissue over the cornea and glued the laboratory-grown stem cells over the injured eye. In cases where both eyes were damaged by burns, cells were taken from an unaffected part of the limbus.

Researchers followed the patients for an average of three years and some as long as a decade. More than three-quarters regained sight after the transplant. An additional 13% were considered a partial success. Though their vision improved, they still had some cloudiness in the cornea.

Patients with superficial damage were able to see within one to two months. Those with more extensive injuries took several months longer.

“They were incredibly happy. Some said it was a miracle,” said one of the study leaders, Graziella Pellegrini of the University of Modena’s Center for Regenerative Medicine in Italy. “It was not a miracle. It was simply a technique.”

The study was partly funded by the Italian government.

Researchers in the United States have been testing a different way to use self-supplied stem cells, but that work is preliminary.

One of the successful transplants in the Italian study involved a man who had severe damage in both eyes as a result of a chemical burn in 1948. Doctors grafted stem cells from a small section of his left eye to both eyes. His vision is now close to normal.

In 2008, there were 2,850 work-related chemical burns to the eyes in the United States, according to the Bureau of Labor Statistics.

Schwab of UC Davis said stem cell transplants would not help those blinded by burns in both eyes because doctors need stem cells to do the procedure.

“I don’t want to give the false hope that this will answer their prayers,” he said.

Dr. Sophie Deng, a cornea expert at the UCLA’s Jules Stein Eye Institute, said the biggest advantage was that the Italian doctors were able to expand the number of stem cells in the lab. This technique is less invasive than taking a large tissue sample from
the eye and lowers the chance of an eye injury.

“The key is whether you can find a good stem cell population and expand it,” she said.

Copyright 2010 The Associated Press. All rights reserved.