Giving patients stem cells packaged with silica nanoparticles could help doctors determine the effectiveness of the treatments by revealing where the cells go after theyve left the injection needle.

Researchers from Stanford University report in a paper published on Wednesday in the journal Science Translational Medicine that silica nanoparticles taken up by stem cells make the cells visible on ultrasound imaging. While other imaging techniques such as MRI can show where stem cells are located in the body, that method is not as fast, affordable, or widely available as an ultrasound scanner, and more importantly, it does not offer a real-time view of injection, say experts.

Stem cells have significant medical promise because they can be turned into other types of living cell. As well as helping doctors adjust therapeutic dosages in patients, the new technique could help scientists perfect stem cell treatments, says senior author Sanjiv Gambhir. For the most part, researchers shoot blindlythey dont quite know where the cells are going when they are injected, they dont know if they home in to the right target tissue, they dont know if they survive, and they dont know if they leak into other tissue types, says Gambhir.

This, in part, could be slowing advances in stem cell treatments. If stem cells are going to be used as a legitimate medical treatment for the repair of damaged or diseased tissue, then we will need to know precisely where they are going so the treatments can be optimized, says Lara Bogart, a physicist at the University of Liverpool. Bogart is developing magnetic nanoparticles for tracking stem cells using MRI.

To get a better view of where cells are going during and after injection, Gambhir and colleagues used nanoparticles made of silica, a material that reflects sound waves, so it can be detected in an ultrasound scan. The nanoparticles were incubated with mesenchymal stem cells, which can develop into cell types including bone cells, fat cells, and heart cells. The cells ingested the nanoparticles, which did not change the cells growth rate or ability to develop into different cell types. Inside the cells, the nanoparticles clumped together, which made them more visible in an ultrasound.

The researchers then injected the nanoparticle-laden stem cells into the hearts of mice and tracked their movements. Many research groups are testing stem cells as a treatment after a heart attack or for other heart conditions in both lab animals (see A Step Toward Healing Broken Hearts with Stem Cells and Injecting Stem Cells into the Heart Could Stop Chronic Chest Pain) as well as in patients in clinical trials. A fast and real-time imaging tool could help because researchers and doctors need to be sure that the cells reach the most beneficial spots in a sickly heart.

Its very important to know where you inject the cells because you dont want to put them in areas damaged by the heart attack; that tissue is dead and a very hostile environment, says Jeff Bulte, a cell engineer at the Johns Hopkins University School of Medicine who was not involved in the study. On the other hand, you want to place them as close to the site of damage as possible, he says.

The silica nanoparticles can also be detected in MRI machines because they contain a strongly magnetic heavy metal known as gadolinium that shows up in the scans. And they can be detected optically (through microscopes) because they carry a fluorescent dye. This gives us three complementary ways to image the same particle, says Bogart. Depending on the part of the body receiving the transplant, the type of scanner available and the amount of time since injection, a researcher may choose one method over another.

The mice used in the study were healthy, but the team plans to test the tracking method in mice or other lab animals that have heart damage. The team will also use the nanoparticles in different cell types and do more toxicity studies prior to filing for FDA approval to test the nanoparticles in humans. It will be about a three-year process to do first-in-man studies, says Gambhir.

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Future medicine: Stem cells can leverage silica nanoparticles to track where they actually go

Mar. 24, 2013 Stem cells taken from amniotic fluid were used to restore gut structure and function following intestinal damage in rodents, in new research published in the journal Gut. The findings pave the way for a new form of cell therapy to reverse serious damage from inflammation in the intestines of babies.

The study, funded by Great Ormond Street Hospital Children's Charity, investigated a new way to treat necrotizing enterocolitis (NEC), where severe inflammation destroys tissues in the gut. NEC is the most common gastrointestinal surgical emergency in newborn babies, with mortality rates of around 15 to 30 per cent in the UK.

While breast milk and probiotics can help to reduce the incidence of the disease, no medical treatments are currently available other than surgery once NEC sets in. Surgical removal of the dead tissue shortens the bowel and can lead to intestinal failure, with some babies eventually needing ongoing parenteral nutrition (feeding via an intravenous line) or an intestinal transplant.

In the study, led by the UCL Institute of Child Health, amniotic fluid stem (AFS) cells were harvested from rodent amniotic fluid and given to rats with NEC. Other rats with the same condition were given bone marrow stem cells taken from their femurs, or fed as normal with no treatment, to compare the clinical outcomes of different treatments.

NEC-affected rats injected with AFS cells showed significantly higher survival rates a week after being treated, compared to the other two groups. Inspection of their intestines, including with micro magnetic resonance imaging (MRI), showed the inflammation to be significantly reduced, with fewer dead cells, greater self-renewal of the gut tissue and better overall intestinal function.

While bone marrow stem cells have been known to help reverse colonic damage in irritable bowel disease by regenerating tissue, the beneficial effects from stem cell therapy in NEC appear to work via a different mechanism. Following their injection into the gut, the AFS cells moved into the intestinal villi -- the small, finger-like projections that protrude from the lining of the intestinal wall and pass nutrients from the intestine into the blood. However, rather than directly repairing the damaged tissue, the AFS cells appear to have released specific growth factors that acted on progenitor cells in the gut which in turn, reduced the inflammation and triggered the formation of new villi and other tissues.

Dr Paolo De Coppi, UCL Institute of Child Health, who led the study, says: "Stem cells are well known to have anti-inflammatory effects, but this is the first time we have shown that amniotic fluid stem cells can repair damage in the intestines. In the future, we hope that stem cells found in amniotic fluid will be used more widely in therapies and in research, particularly for the treatment of congenital malformations. Although amniotic fluid stem cells have a more limited capacity to develop into different cell types than those from the embryo, they nevertheless show promise for many parts of the body including the liver, muscle and nervous system."

Dr Simon Eaton, UCL Institute of Child Health and co-author of the study, adds: "Once we have a better understanding of the mechanisms by which AFS cells trigger repair and restore function in the gut, we can start to explore new cellular or pharmacological therapies for infants with necrotizing enterocolitis."

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Amniotic fluid stem cells repair gut damage

Stem cells taken from amniotic fluid could offer a way to reverse potentially lethal intestinal damage in newborn babies.

In laboratory experiments, scientists used the cells to restore gut structure and function in rats.

The same technique could pave the way for new treatments for the baby condition necrotising enterocolitis (NEC).

NEC is the most common gastrointestinal emergency affecting newborns, with death rates of 15% to 30% in the UK. Once the condition sets in, no options are currently available other than surgery. Some babies end up having to undergo intestinal transplants.

The new research involved injecting rats with NEC with amniotic fluid stem (AFS) cells. A week later, the animals showed significantly higher survival rates than rats not given the stem cell treatment.

Examination of their guts showed inflammation to be greatly reduced, and signs that the intestine was repairing itself.

Dr Paolo De Coppi, from University College London's Institute of Child Health, who led the study published in the journal Gut, said: "Stem cells are well known to have anti-inflammatory effects, but this is the first time we have shown that amniotic fluid stem cells can repair damage in the intestines.

"In the future, we hope that stem cells found in amniotic fluid will be used more widely in therapies and in research, particularly for the treatment of congenital malformations. Although amniotic fluid stem cells have a more limited capacity to develop into different cell types than those from the embryo, they nevertheless show promise for many parts of the body including the liver, muscle and nervous system."

After their injection into the gut, AFS cells moved into the intestinal villi - small finger-like projections that pass nutrients into the blood. Rather than directly repairing the damaged tissue, they appear to release chemicals that stimulate other progenitor cells.

Co-author Dr Simon Eaton, also from the Institute of Child Health, said: "Once we have a better understanding of the mechanisms by which AFS cells trigger repair and restore function in the gut, we can start to explore new cellular or pharmacological therapies for infants with necrotising enterocolitis."

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Stem cells hope for gut condition