stem cells
Despite advances in neurosurgery and radiation techniques, the prognosis for patients with intracranial glioma remains devastating. Now, researchers have identified a possible new treatment strategy for this common type of malignant brain tumor. Two studies funded in part by the National Institute of Neurological Disorders and Stroke (NINDS) show that, in a mouse model, neural stem cells (NSCs) can be used to deliver therapeutic agents capable of killing glioma cells and their migrating tumor cells.
Instead of searching for a kidney donor, a new study suggests, one might be able to grow a new kidney. A team headed by Prof. Yair Reisner of the Weizmann Institute of Science has induced human stem cell tissue to grow into functional kidneys, and have accomplished the same with porcine stem cell tissue. Published in Nature Medicine, the method could lead to a promising solution to the severe shortage of kidney donors.
Researchers in North Carolina have successfully demonstrated that genetically altered stem cells from one species can be turned into a different sort of cell in another. Specifically, the researchers converted adult liver stem cells cloned from a male rat into functional adult bone marrow cells in female mice. The accomplishment, known as hematopoietic transdifferentiation, may prove useful for tapping the potential for tissue repair using human adult stem cells.
Scientists have found a new wrinkle in the developmental biology dogma that cell differentiation occurs irreversibly as stem cells give rise to increasingly specialized types of offspring cells. The researchers have shown that certain mouse cells retain an ability to oscillate between very distinct blood cell types ? B-cells and macrophages ? long after what has been commonly regarded as the point of no return.
Researchers in Los Angeles have combined a special protein that targets cancer cells with neural stem cells to track and attack malignant brain tumor cells. Glioblastoma multiforme, or gliomas, are a particularly deadly type of brain tumor. They are highly invasive with poorly defined borders that intermingle with healthy brain tissue, making them nearly impossible to remove surgically without catastrophic consequences. Furthermore, cells separate from the main tumor and migrate to form satellites that escape treatment and often lead to recurrence.
The Stanford University School of Medicine announced on Dec. 10 plans to form an Institute for Cancer/Stem Cell Biology and Medicine. This multidisciplinary institute will study both stem cell biology and cancer biology, and will attempt to apply knowledge learned from stem cell biology to new treatments for cancer.
Q: Is Stanford planning on cloning human embryos?
A: No. The new institute will study adult stem cell lines generated from individuals with specific diseases such as cancer or neurodegenerative disorders. The institute will also investigate two different ways of generating new embryonic stem cell lines ? initially in mice. This may be extended to human cell lines if the techniques prove useful.
The prospect of using bacteria to manufacture complex human proteins for use in therapeutic drugs is a step closer thanks to new research published today in Science. Researchers from Switzerland and the UK report they have engineered the bacterium Escherichia coli to carry a vital piece of cell machinery that adds sugar molecules to newly synthesized proteins by a process known as glycosylation. The finding opens up the possibility of producing complex human proteins such as Factor VIII and the hormone erythropoietin, which stimulates the production of red blood cells by stem cells in bone marrow. Both these proteins, which require the addition of sugar molecules to function properly, are currently produced by culturing mammalian cells, which can be a costly and technically difficult process.
Researchers have shown that an age-related loss of specific stem cells that continually repair damage to blood vessels is critical to determining the onset and progression of atherosclerosis. Stem cells are immature cells that have the potential to mature into a variety of different cells. This novel view of the disease, based on experiments in mice, constitutes a potential new avenue in the treatment of one of the leading causes of death and illness in the U.S., the researchers said.
Scientists have successfully restored sperm production in once-infertile mice by transplanting specialized cells that are critical to sperm development. The research, reported on the Web site of the journal Biology of Reproduction, may give scientists a better understanding of how Sertoli cells ? which surround spermatogenic stem cells ? nourish sperm production and the survival of stem cells.
Researchers at Stanford University have tracked the path of bone marrow stem cells as they transform into an adult tissue. This work, published in the Nov. 15 issue of the journal Cell, marks the first time scientists have seen the individual steps of the progress. In previous work, researchers have seen injected bone marrow cells integrate into the muscles, livers and brains of mice. But until now, they have not witnessed the sequence of events that leads to this transformation. In their Cell paper, the researchers describe how they saw transplanted bone marrow cells first locate to the muscle as a muscle-specific stem cell called a satellite cell. These former bone marrow cells lurked in the muscle until exercise-induced muscle damage signaled them to help repair the injury by fusing with existing muscle cells.
Biologists have shown for the first time in the laboratory that they can convert some adult human neural stem cells to brain cells that can produce dopamine, the brain chemical missing in Parkinson's disease. If the researchers can better understand the process and harness this ability, the work may someday lead to new strategies in treating neurodegenerative diseases such as Parkinson's.
Using neural stem cells to hunt down and kill cancer cells, researchers have successfully tested a new treatment for brain cancer. They now hope the technique will lead to an effective treatment for glioma, the most aggressive form of primary brain tumor in humans. As the Cedars-Sianai researchers note, the prognosis has historically been extremely poor for patients diagnosed with malignant gliomas. The tumors have poorly defined margins, and glioma cells often spread deep into healthy brain tissue making their surgical removal difficult. Often, pockets of tumor cells break off from the main tumor and migrate deep into non-tumorous areas of the brain. Therefore, even if the original tumor is completely removed or destroyed, the risk of recurrence is high as cells in these distant "satellites" multiply and eventually re-form a new brain tumor. Due to these characteristics, treating brain cancer has been extremely difficult.
This weekend I sank my teeth into some delicious beef ribs. But researchers at the Forsyth Institute say they've done one better ? they've sunk pork teeth into rat guts. The experiment involved taking seeded cells from immature teeth of six-month-old pigs and placing them in the intestines of rats (who no doubt were thrilled at the addition). Within 30 weeks, small tooth crowns made of enamel and dentin had formed. Within five years, the Forsythe team says, they hope to be able to harvest teeth of specific size and shape, and five years after that to regrow human teeth.
