Stem cell really applicable in humans?

So yesterday I posted an article that discusses the imminent setbacks to commonly used multivitamins. Although the study mainly focused on only females, we should treat daily use of multivitamins with caution. Clearly, more studies have to be conducted and one take home lesson that we can gain from this is simple: try your best to get all kinds of vitamins and minerals from fresh foods especially fruits, vegetables, whole grains, nuts and lean meat.

Today, I would like to share with you guys an article that is really mind boggling considering the much hopefulness in the future of stem cell application to cure diseases. There you go:

A neural stem cell transplant from fetal cells performed in Russia led to a brain tumor in a teenage boy, researchers in this week's PLoS Medicine report, raising concerns about the safety of neural stem cells treatments.

MRI of brain lesion, courtesy of PLoS Medicine

The researchers confirmed that the cancer originated from the donor tissue, not the boy's own cells. This is the first report of cancer following fetal neural stem cell transplant.

However, outside experts raised concerns about the safety of the transplant procedure used in this case, suggesting that other stem cell transplants conducted with more oversight may not carry an increased risk.

The boy suffered from a recessive genetic disorder called ataxia telangiectasia (AT), an incurable, neurodegenerative disease that has left him wheelchair-bound. In 2002, when he was 9, his parents took him from Israel to Moscow to undergo experimental stem cell therapy. A team of researchers in Moscow injected multiple transplants of neural stem cells, which were derived and purified from the brains of aborted fetuses.

Four years later, the boy was diagnosed with a very slow growing form of cancer called glioneural neoplasm after coming to the Sheba Medical Center outside Tel Aviv, Israel, complaining of headaches.

A team led by Gideon Rechavi, a pediatric hematologist and oncologist at Sheba Medical Center, performed a histological analysis on the tumor to determine its makeup. They found it contained a hodgepodge of different cell types -- this is unlike most brain tumors, which arise from a single cell type, he said. The different types suggest that the tumor "originated from a stem cell that can differentiate towards various directions," said Rechavi.

To rule out the possibility the tumor came from the boy's own cells, given that AT weakens the immune system and can predispose patients to cancer, the researchers tried to determine its source. The team found that the tumor could not have arisen from the boy, because he is homozygous for the mutation that causes AT, while the DNA from the tumor cells carried only the normal allele.

"This paper does a very good job of showing that the cells that constituted this tumor did not arise from the patient and [were] not genetically identical to either of the parents, and clearly came from the donor tissue," said Arnold Kriegstein, a researcher at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at the University of California, San Francisco.

The case study raises a number of questions. Because the patient's immune system was impaired, it's not yet clear whether the increased risk of cancer is specific to patients with suppressed immune systems, something particular to the procedure done in Moscow, or a danger with neural stem cell transplantation in general, said Uri Tabori, a pediatric hematologist and oncologist at the Hospital for Sick Children in Toronto, Canada. "This is a case report," he said. "It has its role in saying it can happen, but we don't know if it's common, if it's uncommon," he said.

"It's a cautionary tale for studies currently being done in the US and elsewhere," said Kriegstein.

Since the patient developed the brain tumor four years after the initial injections, researchers may need to monitor patients for a long time after a treatment to evaluate safety, Kriegstein said.

However, it's premature to translate these findings to studies conducted in the US, said Aileen Anderson, a neuroscientist who studies stem cells at the University of California, Irvine. The researchers who conducted the transplant followed the protocol of a group that has published only one other paper in an international, peer-reviewed journal, and the cells used are a mixture of glial cells, neurons, and progenitors -- "a sort of cell mush," she said. These are "completely uncharacterized populations, populations that would never be accepted in the US or any first-world country," she said.

Kriegstein agreed. "It's absolutely scary," that the group conducted the transplant, he said.

Currently, a company called Stem Cells, Inc., is conducting a Phase I clinical trial to evaluate the safety of fetal neural stem cell transplants for treatment of Batten Disease, an invariably fatal neurodegenerative disorder that affects young children.

Copied from:
TheScientist.com
Stem cell therapy triggers tumor

Posted by Tia Ghose

[Entry posted at 18th February 2009 01:24 AM GMT]

Multivitamins, the do-it-all pills??

My first article will center around the most widely used supplements in the US and probably most countries, multivitamins. With the big hype and alleged potential benefits of multivitamins, many people are consuming these pills without constraint or proper medical advice. Do they really work to our benefits? Let's look at this article which clearly does not point us to a very convincing idea of unrestrained multivitamin consumption.

The study tracked 161,808 participants in the Women's Health Initiative, a long-term effort to identify risk factors for cancer, heart disease and bone health in postmenopausal women. Subjects in the nationwide study included white, black, Latina, Asian and Native American women. They were followed for an average of nearly eight years.

Overall, 41.5% of study participants took some version of a multivitamin. Those women were more likely to be white and college-educated, live in the West, exercise and have a lower body mass index.

However, women who took multivitamins weren't any more likely to ward off a diagnosis of breast, ovarian, lung, stomach, bladder, kidney, colorectal or endometrial cancer than were women who didn't take multivitamins. Nor were multivitamins in general helpful in preventing heart attacks, strokes, blood clots or reducing the risk of death from any cause during the study period.

The research team, led by scientists at the Fred Hutchinson Cancer Research Center in Seattle, did find one modest benefit: The 3,741 women who took stress multivitamins -- formulations with higher doses of several B vitamins along with an extra jolt of vitamin C -- were 25% less likely to have a heart attack. No other correlations between vitamins and health outcomes were statistically significant.

The study provides convincing evidence that multivitamin use has little or no influence on the risk of common cancers, cardiovascular disease or total mortality in postmenopausal women, the authors wrote.

So, they wondered, "Why do millions of Americans use a daily multivitamin for chronic disease prevention when the supporting scientific data are weak?"

Some physicians continue to recommend them as a backstop for patients whose diets may contain nutritional gaps. And since they don't require a prescription, many people simply assume they are safe.

But those assumptions may not be warranted, especially if people wind up overdosing on vitamins and minerals, the researchers wrote.

Marian L. Neuhouser et al. Multivitamin Use and Risk of Cancer and Cardiovascular Disease in the Women's Health Initiative Cohorts. Archives of Internal Medicine, Feb 9, 2009

Introduction

I am a graduate student in Nutritional Science at one of the public schools who is specifically interested in prevention and intervention of chronic diseases such as diabetes, cancer and obesity through better understanding of dietary factors and physical activity. I will be posting novel findings and related news regarding dietary intervention in the efforts to promote healthy lifestyle. I will try to update this blog as often as I can. Stay tuned!