Defective gene found to raise risk of type 2 diabetes

People who carry the gene could undergo preventive counseling to adopt a healthful lifestyle and avoid getting ill.

By JUDY SIEGEL-ITZKOVICH
DNA structure [Illustrative] (photo credit: INIMAGE)
DNA structure [Illustrative]
(photo credit: INIMAGE)
International genetic research that included scientists at the University of Haifa has discovered a defective gene that significantly increases the risk of getting type 2 diabetes.
Some 300 researchers have studied more than 100,000 people from several continents and discovered the genetic changes that predict adult-onset diabetes, which is usually linked with obesity, poor diet and lack of physical activity.
Prof. Gil Atzmon of the University of Haifa and the Einstein Institute in New York participated in the research that found a candidate gene: PAX-4.
“If we manage to develop a drug that imitates proper functioning of the gene, we will be able to dramatically change the process of treating type 2 diabetes patients,” he said, “and in the future maybe even be able to cope with it even before it breaks out.”
The study, recently published in the prestigious journal Nature, found – among the hundreds of genes that might predict the outbreak of the metabolic disease – a gene whose changes significantly raise the risk of type 2 diabetes, which is considered to be an “epidemic” in the overweight Western world. PAX-4 was found to raise the risk of the disease by an astounding 80 percent.
People who carry the gene could undergo preventive counseling to adopt a healthful lifestyle and avoid getting ill, said Atzmon, who added that the researchers did not prove that carrying the gene actually causes diabetes to occur, but that it occurs in people who are at high risk.
“Today, it is not accepted that genetic tests are conducted on specific age groups to identify the risk for diabetes, but the new discovery could lead to such screening,” he concluded.
TREATING ‘WARNING STROKE’ CAN SAVE LIVES
Although transient ischemic attacks (TIA) of the brain, caused by blood clots, are often labeled “mini-strokes,” they are more accurately characterized as “warning strokes” that people should take very seriously because they could mean a stroke will follow.
Now, the stroke unit at Jerusalem’s Shaare Zedek Medical Center has opened a unique service that treats TIA patients and those who have had mild strokes.
Ever year, some 15,000 Israelis are hospitalized after a stroke. Up to 25% had a barely noticed TIAs beforehand that should have alerted them of danger. The symptoms of the transitory attack were vision and speaking problems, weakness or numbness of the limbs that disappeared within 24 hours without treatment.
Research published in the New England Journal of Medicine recently found that the risk of having a stroke between two days and a year after a TIA was 50% if the TIA was treated immediately.
It is the first such center in the country that will accept patients referred to it by their family physician after they complain of TIA symptoms; they will be admitted immediately to the stroke center and not have to go through the emergency department first.
At the Jerusalem center, a neurologist assesses patients who complained of TIA symptoms to their personal physician. They are seen immediately by a hospital neurologist who conducts tests. Dr. Roni Eichel, head of the stroke unit, who runs the new service, said that after a TIA, patients have a “window of opportunity to prevent real loss. Their clot can be dissolved in time. Usually young people who complain of such symptoms in the average hospital emergency department are not taken seriously. Thus the attention they would receive from the TIA service, which operates Sundays through Thursdays from 8 a.m. to 3 p.m. can reduce the risk of paralysis significantly,” said Eichel.
FIRST-EVER RESTORATION OF VISION IN MICE
Perhaps blindness due to damaged optic nerves is not as irreversible as once thought.
Experiments at Stanford University School of Medicine in California have succeeded, for the first time, in restoring multiple key aspects of vision in mammals.
Published recently in Nature Neuroscience, the scientists coaxed optic-nerve cables – responsible for conveying visual information from the eye to the brain – into regenerating after they had been completely severed, and found that they could retrace their former routes and re-establish connections with the appropriate parts of the brain. That unprecedented, if partial, restoration could pave the way for future work that will enable some blind people to see.
The animals’ condition prior to the scientists’ efforts to regrow the eye-to-brain connections resembled glaucoma, the second-leading cause of blindness after cataracts. Cataracts can often be surgically removed, but there’s no cure for glaucoma, said the study’s senior author, neurobiology Prof. Andrew Huberman, and Jung-Hwan Albert Lim, a graduate student at the University of California-San Diego.
Glaucoma, caused by excessive pressure on the optic nerve, affects nearly 70 million people worldwide.
Vision loss due to optic-nerve damage can also accrue from injuries, retinal detachment, pituitary tumors, various brain cancers and other sources.
The retina, a sheet of cells no more than half as thick as a credit card, is the light-sensing part of the eye. If nerve cells were offices, this tiny patch of tissue would be Manhattan. Photoreceptor cells in the back of the retina react to different wavelengths of light by sending electrically coded information to other cells in the retina called retinal ganglion cells, of which there are as many as 30 types, each specializing in processing a particular aspect of vision, such as upward motion, motion in general, or the color red. The ganglion cells project long, electric-wire-like processes called axons, which extend down the optic nerve in a bundle and then fan out to numerous regions of the brain, where they connect with other nerve cells to inform them about the visual world.
“Somehow the brain can interpret these electrical signals to say, ‘Wow, that’s a fast-moving car coming my way – I’d better get back on the sidewalk,’” said Huberman.
Tests of the mice’s vision indicated that visual input from the photoreceptor cells in their damaged eye was reaching retinal ganglion cells in the same eye and, crucially, being conveyed to appropriate downstream brain structures essential to processing that visual input.
One test, for example, involved the projection of an expanding dark circle – analogous to a bird of prey’s approach – onto the visual field of the damaged eye. In response, most of the mice subjected to both mTOR-pathway upregulation and visual stimulation, as well as obstruction of their good eye, did what they would be expected to do in the wild: they headed for the shelter of a “safety zone” in the experimental set-up.
In other words, the regenerating axons, having grown back to diverse brain structures, had established functional links with these targets. The mice’s once-blind eye could now see.