- Email: [email protected]
Spaghetti junction bridges gaps in broken spines
THIS WEEK
Spaghetti junction regrows spinal cord Andy Coghlan
INSPIRED by hollow spaghetti called bucatini, researchers in Italy have developed implants that help spinal cords regrow. Rats with spinal cord injuries recovered mobility in their hind legs, raising hope that the approach might one day help people with paraplegia. The “bucatini project” is one of several around the world pioneering biodegradable scaffolds to bridge spinal cord injuries. Along with scar tissue, one of the main barriers to healing is the development of fluid-filled cysts at the site of the injury over the ensuing months. The idea of the implants is to create tiny conduits to guide formation of new nerve fibres, or axons, across this fluid-filled space. “These tubes provide the reference points for the cells, and tissue starts to build up,” says Angelo Vescovi of the University of Milan-Bicocca. Vescovi and colleague Fabrizio Gelain built hollow “nano-
Who ate all the planets? Blame the ‘bloatars’ WHEN stars put on weight, it really shows. A group of oddly bloated stars may have grown fat by eating their own planets in a feeding frenzy. No one has ever seen anything quite like the nine stars spotted by the Hubble Space Telescope in a young cluster called NGC 3603. They are too cool to be ordinary stars, with analysis of their infrared light emissions indicating surface temperatures between 1700 and 10 | NewScientist | 12 February 2011
conduits” 2 to 3 millimetres long and about 0.5 millimetres across, from two biodegradable plastics: polycaprolactone and PLGA. To make surfaces more “sticky”, they coated them with chemical hooks called self-assembling peptides, which help to anchor cells along the inside and outside of the tube.
Finally, the researchers filled the tubules with a gel containing natural growth factors that stimulate nerve repair and growth. They then implanted bundles of the tubules into cysts that had formed where the spinal cords of rats had been damaged. Six months later, Vescovi and Gelain found that new nerve fibres had grown all the way through many of the microscopic channels. Some had also grown between the tubes, together with all the other types of supporting cells that nerves need for survival.
Bridging the gap After spinal cord damage, regrowth of severed nerves is inhibited by the formation of a cyst at the site of the injury DEVELOPING NERVE CELLS SEVERED NERVES
SPINAL CORD
FLUID-FILLED CYST
PEPTIDES anchor new cells
GREY MATTER BIODEGRADABLE POLYMER TUBE Implanting a bundle of biodegradable tubules allows nerves to grow across the gap, potentially repairing the spinal cord
2200 kelvin. By this measure, they are more like brown dwarfs, objects intermediate in mass between planets and fully fledged stars. Yet brown dwarfs are dim objects that should be too faint to detect at the cluster’s distance from Earth – 20,000 light years. “We were quite puzzled,” says Loredana Spezzi at the European Space Agency in Noordwijk, the Netherlands. Now Spezzi and her colleagues have another explanation. They think the enigmatic objects are part of stellar systems that spawned planets – then hastily devoured them. Some planets are thought to spiral in towards their stars. That would
explain why so many alien worlds have been found in star-hugging orbits. The team says that some may spiral so close that the star “eats” them – the star’s gravity rips the planet apart and captures its debris. This captured debris would form a temporary outer atmosphere for the star, which would be cooler than the star’s normal light-emitting surface, explaining the apparent low temperatures of the nine mysterious objects.
“This is the first feeding frenzy with many stars in the same cluster all devouring planets”
New blood vessels had also grown, providing a blood supply (ACS Nano, DOI: 10.1021/nn102461w). “Where once there was just a cyst, you have pseudo-tissue that looks just like normal spinal cord tissue,” says Vescovi. Treated animals recovered some mobility in their hind legs, which remained paralysed in the untreated control animals. Vescovi also found chemical markers in the spinal tissue that suggested repair was still under way. “One of the most striking results is the extent and alignment of axonal growth,” says John Priestley at Barts and The London School of Medicine and Dentistry in London. However, a key question, Priestley points out, is whether the neurons are growing into the spinal cord at the other end. “Most previous scaffolds have supported axon growth into the scaffold but not out again. To achieve significant regeneration of spinal circuits, the scaffold must act as a bridge, not a cul-de-sac,” he says. Gelain says that fibres protruded a centimetre beyond the tubules, but without using special dye “tracers”, he could not say whether they were native fibres growing in or regenerated ones growing out. “We will undertake these experiments soon,” he says. n
These bloated stars, or “bloatars”, would also be bigger and brighter than brown dwarfs, explaining how they could be seen at such a great distance, the team says in a paper to appear in The Astrophysical Journal (arxiv.org/1101.4521). Astronomers have previously found a few cases of stars with odd properties that might be explained by planet-eating, including stars containing unusually large amounts of lithium, possibly a consequence of feasting on planets containing the element. But these bloatars are the first example of a feeding frenzy, with many stars in the same cluster all devouring planets. David Shiga n
Spaghetti junction regrows spinal cord Andy Coghlan
INSPIRED by hollow spaghetti called bucatini, researchers in Italy have developed implants that help spinal cords regrow. Rats with spinal cord injuries recovered mobility in their hind legs, raising hope that the approach might one day help people with paraplegia. The “bucatini project” is one of several around the world pioneering biodegradable scaffolds to bridge spinal cord injuries. Along with scar tissue, one of the main barriers to healing is the development of fluid-filled cysts at the site of the injury over the ensuing months. The idea of the implants is to create tiny conduits to guide formation of new nerve fibres, or axons, across this fluid-filled space. “These tubes provide the reference points for the cells, and tissue starts to build up,” says Angelo Vescovi of the University of Milan-Bicocca. Vescovi and colleague Fabrizio Gelain built hollow “nano-
Who ate all the planets? Blame the ‘bloatars’ WHEN stars put on weight, it really shows. A group of oddly bloated stars may have grown fat by eating their own planets in a feeding frenzy. No one has ever seen anything quite like the nine stars spotted by the Hubble Space Telescope in a young cluster called NGC 3603. They are too cool to be ordinary stars, with analysis of their infrared light emissions indicating surface temperatures between 1700 and 10 | NewScientist | 12 February 2011
conduits” 2 to 3 millimetres long and about 0.5 millimetres across, from two biodegradable plastics: polycaprolactone and PLGA. To make surfaces more “sticky”, they coated them with chemical hooks called self-assembling peptides, which help to anchor cells along the inside and outside of the tube.
Finally, the researchers filled the tubules with a gel containing natural growth factors that stimulate nerve repair and growth. They then implanted bundles of the tubules into cysts that had formed where the spinal cords of rats had been damaged. Six months later, Vescovi and Gelain found that new nerve fibres had grown all the way through many of the microscopic channels. Some had also grown between the tubes, together with all the other types of supporting cells that nerves need for survival.
Bridging the gap After spinal cord damage, regrowth of severed nerves is inhibited by the formation of a cyst at the site of the injury DEVELOPING NERVE CELLS SEVERED NERVES
SPINAL CORD
FLUID-FILLED CYST
PEPTIDES anchor new cells
GREY MATTER BIODEGRADABLE POLYMER TUBE Implanting a bundle of biodegradable tubules allows nerves to grow across the gap, potentially repairing the spinal cord
2200 kelvin. By this measure, they are more like brown dwarfs, objects intermediate in mass between planets and fully fledged stars. Yet brown dwarfs are dim objects that should be too faint to detect at the cluster’s distance from Earth – 20,000 light years. “We were quite puzzled,” says Loredana Spezzi at the European Space Agency in Noordwijk, the Netherlands. Now Spezzi and her colleagues have another explanation. They think the enigmatic objects are part of stellar systems that spawned planets – then hastily devoured them. Some planets are thought to spiral in towards their stars. That would
explain why so many alien worlds have been found in star-hugging orbits. The team says that some may spiral so close that the star “eats” them – the star’s gravity rips the planet apart and captures its debris. This captured debris would form a temporary outer atmosphere for the star, which would be cooler than the star’s normal light-emitting surface, explaining the apparent low temperatures of the nine mysterious objects.
“This is the first feeding frenzy with many stars in the same cluster all devouring planets”
New blood vessels had also grown, providing a blood supply (ACS Nano, DOI: 10.1021/nn102461w). “Where once there was just a cyst, you have pseudo-tissue that looks just like normal spinal cord tissue,” says Vescovi. Treated animals recovered some mobility in their hind legs, which remained paralysed in the untreated control animals. Vescovi also found chemical markers in the spinal tissue that suggested repair was still under way. “One of the most striking results is the extent and alignment of axonal growth,” says John Priestley at Barts and The London School of Medicine and Dentistry in London. However, a key question, Priestley points out, is whether the neurons are growing into the spinal cord at the other end. “Most previous scaffolds have supported axon growth into the scaffold but not out again. To achieve significant regeneration of spinal circuits, the scaffold must act as a bridge, not a cul-de-sac,” he says. Gelain says that fibres protruded a centimetre beyond the tubules, but without using special dye “tracers”, he could not say whether they were native fibres growing in or regenerated ones growing out. “We will undertake these experiments soon,” he says. n
These bloated stars, or “bloatars”, would also be bigger and brighter than brown dwarfs, explaining how they could be seen at such a great distance, the team says in a paper to appear in The Astrophysical Journal (arxiv.org/1101.4521). Astronomers have previously found a few cases of stars with odd properties that might be explained by planet-eating, including stars containing unusually large amounts of lithium, possibly a consequence of feasting on planets containing the element. But these bloatars are the first example of a feeding frenzy, with many stars in the same cluster all devouring planets. David Shiga n