ScienceDaily (Feb. 7, 2012) — Broken bones in humans and animals are painful and often take months to heal. Studies conducted in part by University of Georgia Regenerative Bioscience Center researchers show promise to significantly shorten the healing time and revolutionize the course of fracture treatment.
“Complex fractures are a major cause of amputation of limbs for U.S. military men and women,” said Steve Stice, a Georgia Research Alliance Eminent Scholar, animal and dairy scientist in the UGA College of Agricultural and Environmental Sciences and director of the UGA Regenerative Bioscience Center.
“For many young soldiers, their mental health becomes a real issue when they are confined to a bed for three to six months after an injury,” he said. “This discovery may allow them to be up and moving as fast as days afterward.”
Stice is working with Dr. John Peroni to develop a fast bone healing process. “This process addresses both human and veterinary orthopedic needs,” said Peroni, an associate professor of large animal surgery in the UGA College of Veterinary Medicine and a member of the RBC.
Peroni and Stice are leading a large animal research project funded by the U.S. Department of Defense. The project includes scientists and surgeons from the Baylor University College of Medicine, Rice University and the University of Texas, who conducted the early studies.
Engineering new bone
“Healing of critical-size defects is a major challenge to the orthopedic research community,” Peroni said. “Large-bone defects must be stabilized and necessitate technologies that induce rapid bone formation in order to replace the missing tissue and allow the individual to return to rapid function. To date, no single material can suffice.”
The group they lead is a multidiscipline and multi-institutional group actively working on bone tissue engineering.
“Our group has been working productively together on numerous projects through the last several years,” Stice said, “So, a collegial relationship and successful collaborative working relationship is already established.”
Between 2009 and 2011, the collaborations received a $1.4 million grant from the DOD for the use of stem cells in fracture healing to be tested in sheep.
“In our experiences with large animal models, following the guidelines established by our animal care and use committee,” Stice said, “we have been successful in formulating a product that contains mesenchymal stem cells and allows them to survive in the environment of the fracture long enough to elicit the rapid formation of new bone.”
This year, the group showed bone can be generated in sheep in less than four weeks. The speed in which bone is formed is one of the truly unique features of this study.
To start the bone regeneration process, the RBC used adult stem cells that produce a protein involved in bone healing and generation. They then incorporated them into a gel, combining the healing properties into something Stice calls “fracture putty.”
With Peroni’s assistance, the Houston-based team used a stabilizing device and inserted putty into fractures in rats. Video of the healed animals at two weeks shows the rats running around and standing on their hind legs with no evidence of injury. The RBC researchers are testing the material in pigs and sheep, too.
“The small-animal work has progressed, and we are making good progress in large animals,” he said.
More work is needed to get to human medical trials, but the threat of losing federal funding for biomedical work through the DOD means they will have to find new ways to fund the project.
“The next step is to show that we can rapidly and consistently heal fractures in a large animal,” Peroni said, “then to convert it to clinical cases in the UGA [College of Veterinary Medicine] clinics where clinicians treat animals with complex fractures all the time.”
Once they have something that works for animals, it will be passed over to the DOD for human use.
Peroni, who is chairman of the North American Veterinary Regenerative Medicine Association, is hopeful this material will be promoted to the veterinary and human medical fields through the educational efforts of NAVRMA and the RBC.
However, the RBC isn’t the only group working on a faster fix for broken bones.
“Our approach is biological with the putty,” Stice said. “Other groups are looking at polymers and engineering approaches like implants and replacements which may eventually be combined with our approach. We are looking at other applications, too, using this gel, or putty, to improve spinal fusion outcomes.”
One of the best hopes for the fracture putty is in possible facial cranial replacements, an injury often seen on the battlefield.
The project ends in mid-2012. “By then we are to deliver the system to the DOD,” Stice said.
ScienceDaily (Feb. 7, 2012) — It’s big, it’s old and it lives under the sea — and now an international research collaboration with The University of Western Australia’s Ocean’s Institute has confirmed that an ancient seagrass holds the secrets of the oldest living organism on Earth.
Ancient giant Posidonia oceanicareproduces asexually, generating clones of itself. A single organism — which has been found to span up to 15 kilometres in width and reach more than 6,000 metric tonnes in mass — may well be more than 100,000 years old.
“Clonal organisms have an extraordinary capacity to transmit only ‘highly competent’ genomes, through generations, with potentially no end,” said Director of UWA’s Oceans’ Institute Winthrop Professor Carlos Duarte.
Researchers analysed 40 meadows across 3,500 kilometres of the Mediterranean sea. Computer models helped demonstrate that the clonal spread mode of Posidonia oceanica, which as all other seagrasses can reproduce both sexually and asexually, allows them to spread and maintain highly competent clones over millennia, whereas even the most competent genotypes of organisms that can only reproduce sexually are lost at every generation.
“Understanding why those particular genomes have been so adaptable to a broad range of environmental conditions for so long is the key to some interesting future research,” Professor Duarte said.
Seagrasses are the foundation of key coastal ecosystems but have waned globally for the past 20 years. Posidonia oceanicameadows are now declining at an estimated rate of five per cent annually.
“The concern is that while Posidonia oceanica meadows have thrived for millennia their current decline suggests they may no longer be able to adapt to the unprecedented rate of global climate change.”
The genus Posidonia occurs only in the Mediterranean and Australian waters.
The findings have been published in the online journal PLoS ONE.
ScienceDaily (Feb. 7, 2012) — The Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany, has completed the genome sequence of a Denisovan, a representative of an Asian group of extinct humans related to Neandertals.
In 2010, Svante Pääbo and his colleagues presented a draft version of the genome from a small fragment of a human finger bone discovered in Denisova Cave in southern Siberia. The DNA sequences showed that this individual came from a previously unknown group of extinct humans that have become known as Denisovans. Together with their sister group the Neandertals, Denisovans are the closest extinct relatives of currently living humans.
The Leipzig team has now developed sensitive novel techniques which have allowed them to sequence every position in the Denisovan genome about 30 times over, using DNA extracted from less than 10 milligrams of the finger bone. In the previous draft version published in 2010, each position in the genome was determined, on average, only twice. This level of resolution was sufficient to establish the relationship of Denisovans to Neandertals and present-day humans, but often made it impossible for researchers to study the evolution of specific parts of the genome. The now-completed version of the genome allows even the small differences between the copies of genes that this individual inherited from its mother and father to be distinguished.
On February 8 the Leipzig group makes the entire Denisovan genome sequence available for the scientific community over the internet.
“The genome is of very high quality,” says Matthias Meyer, who developed the techniques that made this technical feat possible. “We cover all non-repetitive DNA sequences in the Denisovan genome so many times that it has fewer errors than most genomes from present-day humans that have been determined to date.”
The genome represents the first high-coverage, complete genome sequence of an archaic human group — a leap in the study of extinct forms of humans. “We hope that biologists will be able to use this genome to discover genetic changes that were important for the development of modern human culture and technology, and enabled modern humans to leave Africa and rapidly spread around the world, starting around 100,000 years ago” says Pääbo. The genome is also expected to reveal new aspects of the history of Denisovans and Neandertals.
The group plans to present a paper describing the genome later this year. “But we want to make it freely available to everybody already now” says Pääbo. “We believe that many scientists will find it useful in their research.”
The project is made possible by financing from the Max Planck Society and is part of efforts since almost 30 years by Dr. Pääbo’s group to study ancient DNA. The finger bone was discovered by Professor Anatoly Derevianko and Professor Michail Shunkov from the Russian Academy of Sciences in 2008 during their excavations at Denisova Cave, a unique archaeological site which contains cultural layers indicating that human occupation at the site started up to 280,000 years ago. The finger bone was found in a layer which has been dated to between 50,000 and 30,000 years ago.
ScienceDaily (Feb. 7, 2012) — ESA’s Mars Express has returned strong evidence for an ocean once covering part of Mars. Using radar, it has detected sediments reminiscent of an ocean floor within the boundaries of previously identified, ancient shorelines on Mars.
The MARSIS radar was deployed in 2005 and has been collecting data ever since. Jérémie Mouginot, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) and the University of California, Irvine, and colleagues have analysed more than two years of data and found that the northern plains are covered in low-density material.
“We interpret these as sedimentary deposits, maybe ice-rich,” says Dr Mouginot. “It is a strong new indication that there was once an ocean here.”
The existence of oceans on ancient Mars has been suspected before and features reminiscent of shorelines have been tentatively identified in images from various spacecraft. But it remains a controversial issue.
Two oceans have been proposed: 4 billion years ago, when warmer conditions prevailed, and also 3 billion years ago when subsurface ice melted, possibly as a result of enhanced geothermal activity, creating outflow channels that drained the water into areas of low elevation.
“MARSIS penetrates deep into the ground, revealing the first 60-80 metres of the planet’s subsurface,” says Wlodek Kofman, leader of the radar team at IPAG.
“Throughout all of this depth, we see the evidence for sedimentary material and ice.”
The sediments revealed by MARSIS are areas of low radar reflectivity. Such sediments are typically low-density granular materials that have been eroded away by water and carried to their final destination.
This later ocean would however have been temporary. Within a million years or less, Dr Mouginot estimates, the water would have either frozen back in place and been preserved underground again, or turned into vapour and lifted gradually into the atmosphere.
“I don’t think it could have stayed as an ocean long enough for life to form.”
In order to find evidence of life, astrobiologists will have to look even further back in Mars’ history when liquid water existed for much longer periods.
Nevertheless, this work provides some of the best evidence yet that there were once large bodies of liquid water on Mars and is further proof of the role of liquid water in the martian geological history.
“Previous Mars Express results about water on Mars came from the study of images and mineralogical data, as well as atmospheric measurements. Now we have the view from the subsurface radar,” says Olivier Witasse, ESA’s Mars Express Project Scientist.
“This adds new pieces of information to the puzzle but the question remains: where did all the water go?”
Mars Express continues its investigation.
with passion & gratitude — jennifer