Discover - July/August 2011

Science
News
Hit “Print,” Make
Blood Vessels

On-demand replacement body parts inched closer to reality with the announcement from San Diego biotech company Organovo that its organ “printer” had created the first artificial blood vessel made entirely from human cells, with no synthetic scaffolding.

Instead of dispensing ink, Organovo’s bioprinter uses two robotic tips to deposit globs of cells—in this case, endothelial cells that line blood-vessel walls, smooth muscle cells that regulate vessel dilation and contraction, and structural fibroblast cells. The printer takes 45 minutes to create a four-inch-long tube with a diameter of a few hundredths of an inch. Researchers flush the tube with nutrients to mimic blood flow, allowing the vessel to mature for about a month.

Organovo chief scientist Gabor Forgacs plans to test the printed vessels in animals late this year. If the vessels perform well, they could be particularly useful for bypass surgery. Currently, surgeons working to reroute blood around an obstruction must harvest healthy veins from elsewhere in the patient’s body. “For decades, people have been trying to come up with a replacement,” says Craig Kent, a vascular surgeon at the University of Wisconsin at Madison and a scientific adviser to Organovo. “We hope these printers will help us cross the finish line.” Eventually, more complex print-outs, such as kidneys, may compensate for shortfalls in donated organs. JOSEPH CALAMIA

Spicy Rat Breath Reveals Memory Secrets

In their study, Bontempi’s team
fed cumin-spiced food to a set of rats
and then introduced them to another
group, whose frontal cortex had been
temporarily cut o; from communica-
tion with the hippocampus. One week
later, the altered rats still enjoyed grub
;avored with the spice, as expected. A
month out, however, their preference
for cumin had vanished—confirma-
tion that long-term memories cannot
form without a link between the hip-
pocampus and the frontal cortex.
Bontempi proposes that the hippo-
campus tags cells in the cortex at the
moment of a memory-generating
experience. Breaking communication
between the brain regions may inter-
fere with tagging and subsequently
handicap long-term memory. For rats,
that means forgetting a morsel is safe.
The finding has important impli-
cations for humans, too. Bontempi
believes that it could eventually lead to
treatments for memory-loss disorders
that a;ect the hippocampus, such as
Alzheimer’s. ;;;;;; ;;;;;
NEURO BEAT

;;;; ;;; ;;;;;;;;; ;;;; ;; aroma can sear the scent into your memory for years. The same thing happens in rats, and researchers from the University of Bordeaux in France have exploited this to gain important insight into memory formation.

When the brain encounters an odor, it temporarily saves the data in the banana-shaped hippocampus. But it is the frontal cortex that eventually encodes the memory into long-term storage. To decipher how that process unfolds, neurobiologist Bruno Bontempi and colleagues took advantage of a rather rude behavior in rats: ;e rodents often smell the breath of their fellow creatures to determine whether a new food is safe to eat. A single encounter can generate a lasting memory of the agreeable meal.

ISTOCK

NUMBER;

Disappearances

BY MARA GRUNBAUM

10,000

Number of shipping containers (of about 200 million
transported annually) estimated to fall off cargo
ships and into the ocean every year. In March
marine scientists explored a container that landed
off California in 2004 and saw crabs, octopuses, and
snails living on and around it. Lost containers may act
as ecological stepping-stones, allowing coastal spe-
cies to hop from one to the next into new territory. 176 Number of African penguin chicks at a rehabilitation center in South Africa with a puzzling disorder that caused them to lose all their feathers, according to a study published last year. About one in five captive chicks with the disorder died bald; the rest recovered and regrew their plumage. Feather loss also turned up in wild African penguins and in four Argentinian colonies of Magellanic penguins.