How Transplanted Stem Cells Behave in Injured Spinal Cord Tissue

A representative confocal image of spinal cord tissue fluorescently immunolabeled for SC121 in conjunction with GFAP – markers that allowed the researchers to track stem cell differentiation and migration by stereological quantification. (Image provided by study author Dr. Aileen J. Anderson)

A representative confocal image of spinal cord tissue fluorescently immunolabeled for SC121 (red) in conjunction with GFAP (green) – markers that allowed researchers to quantify stem cell differentiation and migration. (Image provided by study author Dr. Aileen J. Anderson)

Research has shown that transplanting human neural stem cells into damaged spinal cords restores locomotor function in a mouse model of spinal cord injury1. Researchers who worked on that study have published another paper examining how these neural stem cells behave in injured tissue as they aid in healing. Learning how stem cells behave in injured tissue will hopefully help researchers develop better treatments for spinal cord injuries.

In the study, researchers used Stereo Investigator to stereologically quantify the survival, migration, proliferation, and differentiation of human neural stem cells transplanted into injured and uninjured mice. Stem cells were analyzed in mouse brain tissue specimens 1, 7, 14, 28, and 98 days after transplantation. The research found that there were fewer stem cells in the injured animals compared to the uninjured animals at all time points, stem cells in injured mice localized near the center of the injury, a delay of stem cell proliferation in injured tissue led to an overall deficit of actively dividing cells, proliferation in injured mice occurred closer to the injection sites (the locations where the stem cells were injected into the mice), and the injured microenvironment increased differentiation to more mature oligodendrocytes.

Continue reading “How Transplanted Stem Cells Behave in Injured Spinal Cord Tissue” »

Wisconsin Scientists Use Stereo Investigator to Quantify Neurons Formed From Stem Cells

iStock_stem_cells

Researchers at the Waisman Center (University of Wisconsin-Madison) just took a big step in their quest to develop regenerative medicines for treating Parkinson’s, Alzheimer’s, and other neurodegenerative diseases. They used human embryonic stem cells to restore memory and learning in disabled mice.

The study, published last month in Nature Biotechnology, “is the first to show that human stem cells can successfully implant themselves in the brain and then heal neurological deficits,” senior author Su-Chun Zhang told the University of Wisconsin-Madison news department.

Continue reading “Wisconsin Scientists Use Stereo Investigator to Quantify Neurons Formed From Stem Cells” »

UCSD Researchers Make Paralyzed Rats Move Again

Approximately 11,000 Americans become paralyzed from spinal cord injuries each year with little hope for recovery. But new research from the University of California at San Diego saw some promising results.

The research team, led by MBF Bioscience customer Dr. Mark Tuszynski and Dr. Paul Lu saw movement in paralyzed rats after grafting a gel containing neural stem cells to the rats’ injured spinal cords. According to an article in The San Diego Union-Tribune, the process resulted in the growth of tens of thousands of new axons. These axons were “remarkably longer” than those scientists had seen in previous studies and ventured beyond the injured area to form new synapses and restore communication with the brain. The rats regained “some power in their joints and were able to move around to a limited degree,” according to the article.

In their abstract, the authors report: “Properties intrinsic to early-stage neurons can overcome the inhibitory milieu of the injured adult spinal cord to mount remarkable axonal growth, resulting in formation of new relay circuits that significantly improve function.”

Dr. Tuszynski’s lab at the UCSD Center for Neural Repair is conducting experiments now to see if their results will translate to humans.

Read the article in The San Diego Union-Tribune, and access the paper “Long-Distance Growth and Connectivity of Neural Stem Cells after Severe Spinal Cord Injury” in the journal Cell to find out more about the study.

{Paul Lu, Yaozhi Wang, Lori Graham, Karla McHale, Mingyong Gao, Di Wu, John Brock, Armin Blesch, Ephron S. Rosenzweig, Leif A. Havton, Binhai Zheng, James M. Conner, Martin Marsala, Mark H. Tuszynski “Long-Distance Growth and Connectivity of Neural Stem Cells after Severe Spinal Cord Injury” Cell, Volume 150, Issue 6, 14 September 2012, Pages 1264–1273}

Photo of Dr. Tuszynski courtesy of the University of California at San Diego.

Science News: Stanford Scientists Make Neurons from Skin Cells

Take a set of skin cells, add four genes, wait four to five weeks, and you’ve got a batch of functioning neurons. Scientists at The Stanford University School of Medicine came up with this revolutionary recipe that uses transdifferentiation, a cellular reprogramming process that turns one type of cell directly into another, without first converting it into a pluripotent stem cell.

Last year, the research team did this with mice. They created neurons from cells derived from mouse tails by adding a trio of genes known as “BAM” (Asc11, Brn2, and Mytl1). When they tried this combination on human cells, they formed what appeared to be neurons, but closer inspection showed these cells weren’t firing the electrical impulses characteristic of a functioning nerve cell. However, when a fourth gene came into the picture, the transcription factor called NeuroD, the neurons not only became electrically active, they formed synapses with mouse neurons grown in the same dish.

In the news release from Inside Stanford Medicine, Marius Wernig, MD, assistant professor of pathology and a member of Stanford’s Institute for Stem Cell Biology and Regenerative Medicine  says “We are now much closer to being able to mimic brain or neurological diseases in the laboratory. We may perhaps even be able to one day use these cells for human therapies.”

Read more about the study at Inside Stanford Medicine.

{Image Credit: Dan Peruzzi, Ph.D.}

If you enjoyed this article, like MBF Bioscience on Facebook and follow us on Twitter

Stereo Investigator Assists Stanford Stroke Center Scientists in Stem Cell Research

A stroke can leave its victim mentally and physically devastated. Recovery is demanding, and takes drive and determination. If the patient doesn’t receive medical attention within the small, critical window of time after the stroke occurs, chances of a quick recovery are slim. Developments in stem cell research find doctors optimistic about new possibilities for stroke rehabilitation.

Scientists at the Stanford Stroke Center, one of the leading centers for stroke research in the world, are working on figuring out how transplanted stem cells affect the host brain. They’re specifically working toward determining which trophic factors—substances secreted by cells—are necessary for stem cell transplantation to be effective. One recent study focused on vascular endothelial growth factor (VEGF), a factor associated with neurological recovery in stroke patients.

As described in their paper “Transplanted Stem Cell-secreted VEGF Effects Post-stroke Recovery, Inflammation, and Vascular Repair,” Drs. Nobutaka Horie, Gary Steinberg, and their team of researchers found VEGF to be essential for hCNS-SCns-induced recovery. The research team studied the brains of rats, which had undergone stroke surgery and were injected with human central nervous system stem cells (hCNS-SCns). After thorough analysis of various parameters, including stereological quantification of the brain inflammatory response and stem cell survival using Stereo Investigator, the Stanford team determined the stem cells helped suppress inflammation, helped form new blood vessels, and improved blood-brain barrier integrity.”

“Subacute cell transplantation therapy offers a multimodal strategy for brain repair that could significantly expand the therapeutic window for stroke,” say the authors in “Transplanted Stem Cell-secreted VEGF Effects Post-stroke Recovery, Inflammation, and Vascular Repair.”

Access the free abstract or download the full article at Stem Cells.

Horie, N., Pereira, M. P., Niizuma, K., Sun, G., Keren-Gill, H., Encarnacion, A., Shamloo, M., Hamilton, S. A., Jiang, K., Huhn, S., Palmer, T. D., Bliss, T. M. and Steinberg, G. K. (2011), Transplanted Stem Cell-Secreted Vascular Endothelial Growth Factor Effects Poststroke Recovery, Inflammation, and Vascular Repair. STEM CELLS, 29: 274–285. doi: 10.1002/stem.584

{Image of transplanted stem cells (pink) and blood vessels (green) courtesy of Stanford University}

For the latest news about MBF Bioscience and our customers, like us on Facebook and follow us on Twitter

 

Stem Cell Transplants Aid in Spinal Recovery

SCI-Figure-9

by Dan Peruzzi, PhD.

Thousands of people in the United States have spinal cord injuries (SCIs), with associated loss of movement and sensation below the site of the injury. Neural and glial cell transplants into research animals after SCI have correlated with recovery of function. The improvement may be caused by the transplanted cells; it’s thought that remyelination by the transplanted glial cells is the main reason for the improvement. Also, if adult neural stem cells are transplanted, there is evidence they form new neurons. In “Analysis of Host-Mediated Repair Mechanisms after Human CNS-Stem Cell Transplantation for Spinal Cord Injury: Correlation of Engraftment with Recovery” (2009, Hooshmand MJ, Sontag CJ, Uchida N, Tamaki S, Anderson AJ, Cummings BJ, PLoS One) the authors use Stereo Investigator’s powerful quantitative tools to determine whether changes in the host environment may also be correlated with improved function.

Using Stereo Investigator, specific aspects of the host milieu were compared between spinal cord injured animals (Non-Obese-
Diabetic-severe combined immunodeficient mice) that received transplants of human central nervous system-stem cell neurospheres (hCNS-SCns) and those that did not. The sampling parameters such as section interval, grid size, and counting frame size, were determined by checking the coefficient of error to make sure it was low. In some cases, additional post-hoc power analysis of data from previous publications was used to demonstrate that the parameters were appropriate for the required precision. Serotonergic fiber length was estimated using the Isotropic Virtual Planes probe with a 60X objective. Blood vessel length was estimated using the Space Balls probe with a 40X objective. The areas and volumes of lesions, spared tissue, and astrogliosis, were estimated using the Cavalieri probe with a 20X objective. Stereological results were complimented by biochemical protein analysis. In addition, the Optical Fractionator probe was used to estimate a non-host parameter, the number of neurons that live and proliferate from the hCNS-SCns transplant.

There were no differences found in the host characteristics between hCNS-SCns transplant animals and control animals. For example, there was no difference in the length of blood vessels. Platelet/ endothelial cell adhesion molecule immunohistochemistry was used to identify blood vessels. Some treatments following CNS trauma may promote behavioral recovery associated with vascular remodeling. Blood vessel length was estimated at the injury center, one mm rostral, and one mm caudal to the injury. There was no statistical difference between controls and hCNS-SCns transplanted animals (see figure, controls are vehicle and human fibroblasts (hFb)). Regarding the non-host characteristic of how many transplanted cells lived, multiplied, and migrated, the Optical Fractionator estimate showed that the transplanted cell number increased 194 percent after transplantation and migrated from the injection site. Ablation of some transplanted cells with Diptheria toxin correlated with a loss of locomotor recovery. This study shows that the direct consequences of the transplanted cells such as proliferation -
correlate with improved function – while the transplant does not have an effect on host characteristics such as lesion volume,
spared tissue, fiber sprouting, and angiogenesis, ruling out any correlation of an indirect effect of the transplanted stem cells with recovery.

Dan Peruzzi is a staff scientist at MBF Bioscience.

First published in The Scope, fall 2009.