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Posts Tagged ‘artificial organs’

In the event of some horrible accident, which bionic parts would I want replacing my own?

Click to launch a tour of the body parts I'd want in the event of an accident.

Some of these body parts are available now, saving or making lives easier, while some have only been seen in prototype or even just proof of concept form. Some are designed to replace an existing body part with as few sacrifices as possible, and some may even provide an advantage over our flesh-and-bone bodies. This is the current and near-future state of bionics.

Current artificial lungs are inefficient and cumbersome, requiring large tanks of oxygen--their oxygen exchange efficiency is so poor that they can only breathe the pure stuff--that render them more or less stationary. The reliance on pure oxygen also limits their lifespans, as they need a fresh supply every few days.

The new lung, built by Case Western Reserve University researchers, is modeled on the natural human lung and contains a bunch of breathable silicone rubber analogs of blood vessels that branch out like real blood vessels down to the point that they reach a diameter smaller than one quarter that of a human hair. This bio-mimicking miniaturization offers a much better surface-area-to-volume ratio, lending the device its higher oxygen exchange efficiency.

As such, the researchers believe they can pack enough efficiency to match that of the human lung in a package that is also roughly the size of a real lung--meaning that at some point in the future their lung could be implanted in patients. In such a scenario, the device could be driven by the heart, requiring no independent power source to power the lung.

Tests using pig blood have shown that the artificial lung is three to five times more efficient than the current state of the art, and though the initial goal was to improve efficiency and portability of artificial lungs--that is, to get rid of those external oxygen tanks--the team thinks they could have an implantable model in clinical trials within a decade. That is, of course, if we’re not already growing made-to-order replacement lungs in the lab by then.

Tissue engineering, which promises to rebuild or replace injured or failing body parts, has seen some major advancements in recent months, with biological scaffolds used to create new bones in rabbits and regrown muscle in humans. But it’s more difficult to make a complete organ, which has several types of cells that must all function properly.

The small intestine is a good subject for this type of study because it’s a particularly regenerative organ, said Dr. Tracy C. Grikscheit, the lead author of a paper on this research.

Grikscheit and colleagues at The Saban Research Institute of Children's Hospital Los Angeles took samples of mice intestinal tissue, including all the layers of cells — muscle cells and epithelial cells. Then the team transplanted the cells onto a polymer scaffold within the abdomen, a news release explains. Growth factor proteins encouraged the cells to replicate.

New small intestines grew on the scaffold, the researchers say, and they had all the constituents of a normal intestine. The new intestines “contained the most essential components of the originals,” according to the news release.

The research could someday be used to treat various intestinal disorders, including a particular gastrointestinal disease that affects premature babies, according to Children’s Hospital. An engineered replacement organ would conceivably last much longer than a transplant, if one is even available.

A paper on the research is published in the journal Tissue Engineering Part A.

[Science Daily]

Endocrinologists have been presenting new concepts at a meeting of the American Diabetes Association in San Diego, and last week, U.S. regulators released new draft guidelines for a new generation of devices.

Researchers at the Mayo Clinic are developing an artificial pancreas that accounts for slight, low-intensity physical activities that can impact blood sugar levels. The researchers are developing a closed-loop system that includes a glucose monitor, automatic insulin pump, activity monitors that attach to the body and a central computer that uses an insulin-delivery algorithm to determine how much of the hormone to dispense.

A team led by Yogish Kudva at Mayo hooked up diabetics with accelerometers to measure slight movements, and tracked their blood sugars while they moved around after eating a meal. They found that even limited, basic movements had a major impact on blood sugar levels, bringing them close to those of people with normally functioning pancreases. But insulin pumps and glucose monitors don’t account for those slight differences. New algorithms that adjust for those changes could help diabetics better manage their insulin intake, the Mayo researchers said. The team plans to start a clinical trial with the system this year or early next year, according to Bloomberg.

In another study, researchers at Yale University tested an artificial pancreas that automatically senses and regulates glucose throughout the night, and found it worked better than a traditional insulin pump. Twelve patients were hooked up to a glucose monitor manufactured by Medtronic Inc., which sent signals to a laptop, where algorithms calculated how much insulin to administer. The system is simple enough that it could eventually be integrated into a wearable device, according to the researchers.

The Food and Drug Administration last week announced draft guidelines for how to develop some of these systems, including a “low glucose suspend system,” which cuts off insulin delivery when blood sugar levels drop. The device is already approved in Europe.

The FDA plans to release even more detailed plans for closed-loop artificial pancreases by the end of the year, according to Bloomberg.

[Science Daily, Bloomberg]

Scientists have tested the chip’s immune response, and it behaves just like real tissue would, a first step to having lifelike organ systems on which drugs can act. The chip’s primary developer, biomedical engineer Dongeun (Dan) Huh of Harvard University, hopes that within two years, the chip will succeed in mimicking the process by which the lungs swap oxygen for carbon dioxide. Huh would like to create a suite of artificial organs to be used in cosmetics testing and pharmaceutical safety trials.

Click to launch the photo gallery.

Led by a University of California-San Francisco scientist, a consortium of about 10 different research teams unveiled a new artificial kidney prototype this week, saying a room-sized version has already shown promise for the sickest patients. Fabrication processes used to make silicon chips could conceivably be used to make coffee-cup-sized devices, which could take thousands of people off dialysis machines or kidney-donor waiting lists.

The multi-institutional team, led by UCSF professor Shuvo Roy, formerly of the Cleveland Clinic, is the first to demonstrate technology that could be feasibly downsized into a transplant device.

It’s a two-stage system involving thousands of nanoscale filters placed in a “BioCartridge,” which would remove toxins from the blood. A "HemoCartridge" bioreactor made of engineered renal tubule cells would mimic the metabolic and water-balancing roles of a real kidney. The system uses a patient’s blood pressure to perform filtration without the use of pumps, according to a UCSF news release.

Currently, transplants and dialysis are the only ways to treat kidney failure. An implantable device would obviously be preferable, but so far, scientists have not been able to come up with a system that mimics everything the kidney can do.

The new system relies on the latest advances in nanotechnology and tissue generation, Roy said. He hopes to use silicon-fabrication technology to make the device small enough for transplant.

“This could dramatically reduce the burden of renal failure for millions of people worldwide, while also reducing one of the largest costs in U.S. healthcare,” he said.

[ScienceDaily]