The gel doing an impersonation of a trampoline in the video above is a new synthetic material from Harvard engineers, a substance that stretches to more than 20 times its length and can withstand more force than human cartilage, the resilient tissue that cushions our joints.
This machine is weaving 48 strands of human connective tissue together into a tube.
Growing fresh blood vessels is a much fantasized-about goal of biomedical engineers. It sounds vaguely vampiric, but the idea is to replace the veins in the arms of dialysis patients, which are a mess from being breached several times a week to be hooked up to a blood-cleaning machine. From there, engineers hope to provide off-the-shelf replacements for heart valves and such.
Most approaches involve getting human cells—either donor cells or cells from the patient—to manufacture rubbery connective tissue made of proteins, from which the cells are stripped away to avoid an immune reaction in patients. Some companies start with flat sheets of this tissue and roll them into tubes, while others have the cells make the stuff around a tubular mold. One company, though, is trying out a technique that made us look twice. They’re weaving the vessels from thread spun with thin strips of cultured connective tissue, Technology Review reports.
Smooth-muscle cells show green in this comparison of blood vessels grown with (right)
and without (left) growth factor FGF9. Without muscle, vessels don’t pump.
What’s the News: Biologists may have been barking up the wrong tree when it comes to growing new blood vessels to provide blood to tissues damaged by heart disease. The vessels that form under the influence of a growth factor intended to kick-start the process are sickly and shrivel up within a year, but a new study in Nature Biotechnology ($) shows that focusing on making the surrounding cells provide support may solve the problem.
The stem cells formed a sac that then folded in half
a couple days later (see image above, courtesy of Nature),
forming the optic cup.
What’s the News: Give a blob of cells the right environment—lots of nutrients, special chemical signals, and a comfy gel cushion—and they just might grow you a body part. In a feat of bioengineering, scientists at the RIKEN Center for Developmental Biology in Japan have grown a retina from mouse embryonic stem cells. Remarkably, much of the development happened spontaneously, indicating that even undifferentiated cells have a blueprint in mind. Researchers hope the work will someday yield transplantable retinas for people with diseases like retinitis pigmentosa.
“When I received the manuscript, I was stunned, I really was,” commented human molecular geneticist Robin Ali (via Nature News). “I never though I’d see the day where you have recapitulation of development in a dish.”
In a society where pill-popping is the answer to many a medical malady, severely dysfunctional or damaged organs are especially frustrating—they’re usually beyond the reach of any known drugs. Cell-based therapy, though, is no drug: Using patients’ own cells, medical experts have successfully grafted the first engineered-from-scratch urethras.
The story starts with five Mexican boys, aged 10 to 14, whose urethras were damaged beyond repair because of accidents.
“When they first came in, they had a leg bag that drains urine, and they have to carry this bag everywhere they go,” says Dr. Anthony Atala of Wake Forest University in North Carolina. “It’s uncomfortable and painful. So these children were mostly sitting or bed-bound.” [NPR]
Currently the usual treatment calls for an artificial graft, which has a failure chance as high as 50% (and failure here means a lifetime of infections and incontinence). “When an organ or tissue is irreparably damaged or traumatically destroyed, no amount of drugs or mechanical devices will restore the patient back to normal,” regenerative medicine expert Chris Mason, from University College London, told the BBC. Read More