Tag: embryonic stem cells

Food for Thought: Weekly Wrap-Up

Sascha Karberg in Frankfurter Allgemeine Sonntagszeitung (FAS) features the latests attempts of biologists to understand and replicate the endosymbiosis of cyanobacteria and cells of eucaryotes that led to the chloroplasts found in all green plants. Already in the 1970s, biologists successfully incorporated cyanobacteria into an amoeba and meanwhile, several animals carrying endosymbionts providing them with extra energy from the sun have been discovered. This is now replicated in the lab. Using genetically engineered cyanobacteria, scientist recently created zebrafish larvae as well as mice and hamster cells with endosymbionts that not only survive but replicate. Karberg also explains why this will not lead to green cows living on sunlight.

Silvia von der Weiden in Die Welt introduces novel findings about the role of water molecules in protecting and maintaining the DNA geometry. Reducing or expanding the size of the water sheath covering the DNA changes the conformation of the molecule as if activating a switch. The findings may be used to create novel DNA-based nanotools or develop DNA-binding drugs to influence gene activation.

In Forbes, Mattew Herper features a graph proving Moore’s law wrong – at least in the decline of cost of DNA sequencing: the cost of getting DNA data (i.e. cost per genome as well as per megabyte of DNA sequence) is dropping way faster than the cost of processing data on computers. In a separate article, Herper endorses Wall Street’s forecast, that Pfizer’s Prevnar 13 vaccine against pneumococcus infections will be the company’s biggest seller in five years.

The Economist features an Italian engineering firm developing a system to collect oil spills in the sea that is based on wool. Already the company has been granted a patent of its containerized, ship-based kit. After absorbing the oil, the wool is pressed to recover the oil and the reused.

Andrew Pollack in the New York Times reports about setbacks in the development of treatments based on stem cells. Experiments recently  showed that induced pluripotent stem cells – which are thought to be superior both ethically and technically to embryonic stem cells – are rejected by the immune system. However, it is not yet clear whether the results obtained in mice hold true for humans, too.

 

Food for Thought: Weekly Wrap-Up

Joachim Müller-Jung in Frankfurter Allgemeine Zeitung deals with the importance of high quality tissue for the development of personalized cancer therapies. He quotes Catheryn Compton, Director of the NCI’s Office of Biorepositories and Biospecimen Research (OBBR), as saying that billions of dollars have been wasted in the past because researchers developing biomarkers supposed to be predicitive of cancer and responses to therapies relied on tissue samples that were utterly useless:  tissue had been subject to careless handling and storage, and patient histories, data on origin and sampling procedure were missing, so that results were not reproducible. Müller-Jung features Hamburg-based Indivumed as the first and only ISO9001:2008 certified biobank in the world which offers cancer patient tissue and related technical and medical data derived in a standardized procedure accompanied by a detailed protocol.

Jef Akst in The Scientist reports on a new biomarker that can tell at early stages of liver and rare endocrine cancer whether a patient is likely to develop metastases. The biomarker, a protein called CPE-delta N, was able to predict the occurrence of metastases with greater than 90% accuracy, and using the associated RNA as a biomarker, the accuracy was even greater. Preliminary findings suggest it may also be applied to other cancer types.

In the same magazine, Megan Scudellari reports on findings that human cells reprogrammed into multipoint stem cells (so-called induced pluripotent stem cells, or iPS) have hotspots in their genome that are not completely re-programmed. The article raises the question whether iPS are really suited to replace embryonic stem cells.

Detecting volatile substances is the topic of several papers. In New Scientist, Jessica Hamzelou reports on attempts by various research groups to accelerate diagnosis in the operation theater by combining electrosurgery with NMR spectroscopy. The smoke emanating from the cut tissue is directed to a NMR spectrometer which analyses on the spot whether the surgeon is cutting healthy or cancer tissue.

Also in New Scientist, Arlene Weintraub reports on the Israeli start-up BioExplorers which claims that trained mice are better at detecting explosives than currently used devices and methods. As soon as the mice sniff traces of any of 8 explosives, they flee to a side chamber of their cage as if they are smelling a cat. Scientists from Colorado State University have taught tobacco and mouse-ear cress plants a similar trick – exposed to vapors from TNT, the plants change color. The trick is done by reengineering a certain receptor, reports Ferris Jabr. German Spiegel features a publication by Japanese scientists from Kyushu University who trained a dog to sniff out early-stage colon cancer with a success rate of 90%. The researchers now try to find out which chemicals the dog reacts to.

Ben Coxworth in Gizmag reports on blood clots made visible by nanoparticles. Each particle, developed by Dr. Dipanjan Pan at the Washington University School of Medicine  in St. Louis, Missouri, contains a million atoms of bismuth  and molecules binding to fibrin, a key component of blood clots, at the outside. Bismuth is a toxic heavy metal, which can be detected by a spectral CT scanner. In contrast to regular CT scanners, this new type of scanner is capable of displaying detailed objects or metal in color. Coxworth concludes that “not only could the technology be used to locate blood clots, but it could possibly even treat their cause – ruptures in artery walls. If the nanoparticles contained some sort of healing agent, then once they attached to the fibrin in a blood clot, they could set about sealing any weak spots.”

Food for Thought: Posing Stem Cell Therapy at Risk

Many researchers agree that stem cells – whether they originate from embryos or from adults – bear great therapeutic potential. They are toti- or pluripotent cells, which by definition are able to regenerate all sorts of damaged tissue – provided their differentiation is confined to the desired environment, leads to the right type of tissue and can be controlled so as not to give rise to side effects, e.g. tumors.

How to fulfill these preconditions is under thorough investigation in many research institutions, but most experts agree that science is not there yet.

Nevertheless, some researchers have set out to try – and the danger is great that stem cell therapy therefore will follow the thorny gene therapy road that started in the early nineties with unfounded experiments, serious side effects, and deaths of patients.

The first stem cell therapy related death is already there: as reported by German magazine “Wirtschaftswoche” today, this month an eight years old boy died from cerebral hemorrhage after receiving an injection of autologous stem cells into his brain. He had been treated by researchers from German stem cell therapy company XCell-Center (Düsseldorf, Germany). In Germany, autologous stem cell therapies are regarded as individual medicinal products (“Individualarzneimittel”), which require a manufacturing authorization but no regulatory approval as a drug. Already in spring, a ten years old boy developed the same condition after stem cell treatment of his brain by XCell-Center. Luckily, he survived.

But the FDA-approved clinical trial involving embryonic stem cells that started in Atlanta, GA, last week is also met with scepticism by experts. In this trial, the first patient  suffering from spinal cord injury was injected with about 2 million oligodendrocyte progenitor cells derived from human embryonic stem cells. While the researchers of Atlanta’s Shepherd Center and stem cell company Geron Corp., sponsor of the trial,  hope that the cells will form a restorative coating around the damaged spinal cord, experts such as Volker Dietz, professor at Neuroscience Center Zurich and a specialist in treating paraplegic patients, react with “disgust and infuriation”. He told German Sunday paper “Frankfurter Allgemeine Sonntagszeitung” this weekend that the treatment approach was unfounded as the regeneration of nerve cells is far from being understood and previous experiments transplanting coating cells – the cells the US researchers are trying to generate – did not lead to any effects. Dietz said, among his fellow experts, he had “not heard a single positive voice yet”.

After two decades, gene therapy today is a niche application with sparse successes, which is the result of serious blows the field experienced after some of the first patients died from side effects such as leukemias. Consequently, parliaments, regulators, funding agencies and the public as well as investors regarded the field as dangerous and too risky to pursue. With trials not supported by many specialists and the first dead patient, it seems the same scenario is unfolding today. Therefore, today’s  self-styled pioneers of stem cell therapy  not only pose patients at risk, but the field as a whole.