Day: 11/24/2011

Study provides more evidence linking depression to possible dementia later in life

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Imaging Technique Identifies Plaques, Tangles In Brains Of Severely Depressed Older Adults

A small study in older adults who have been diagnosed with severe depression have higher levels of protein deposits on the parts of their brain involved in decision-making, complex reasoning, memory and emotions than counterparts who aren’t experiencing depression, according to the results of a study published in the November issue of the peer-reviewed journal Archives of General Psychiatry.

“The findings suggest that the higher protein load in critical brain regions may contribute to the development of severe depression in late life,” said study co-author, Dr. Gary Small, UCLA’s Parlow-Solomon Professor on Aging and a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA.

Even as depression is one of the most common mental disorders in the elderly, little is known about the underlying biology of its development in older adults. Previous research has suggested that plaque and tangle deposits in the brain—hallmarks of Alzheimer’s disease and many dementias—are associated not only with memory loss but also with mild symptoms of depression and anxiety in middle-aged and older individuals.

Findings

UCLA researchers have created a chemical marker called FDDNP that binds to both plaque and tangle deposits. The marker can then be viewed through a positron emission tomography (PET) brain scan. Using this method, researchers are able to pinpoint where in the brain these abnormal protein deposits are accumulating. The team wanted to see what the brain-scanning technique would find in older people with major depressive disorder (MDD).

Researchers compared the FDDNP brain scans of 20 older adults between ages 60 to 82 who had been diagnosed with MDD with the scans of a control group consisting of 19 healthy individuals of similar age, education and gender. 

They found that in patients with MDD, FDDNP binding was significantly higher throughout the brain and in critical brain regions, including the posterior cingulate and lateral temporal areas. These parts of the brain are involved in decision-making, complex reasoning, memory and emotions.

Researchers also found that similar protein deposit patterns in the lateral temporal and posterior cingulate areas in patients were associated with different clinical symptoms. Some patients demonstrated indicators of depression  while others displayed symptoms of both depression and mild cognitive impairment.

“We may find that depression in the elderly may be an initial manifestation of progressive neurodegenerative disease,” said study co-author, Dr. Anand Kumar, the Lizzie Gilman Professor and department head of psychiatry at the University of Illinois at Chicago. “Brain scans using FDDNP allow us to take a closer look at the different types of protein deposits and track them to see how clinical symptoms develop.”

Future Research

More follow-up over time is needed to evaluate the significance of the outcomes of the study’s patient subgroups, say Kumar and Small. Such research will help researchers determine if depression later in life might be a precursor to mild cognitive impairment and dementia.   

Additionally, FDDNP used with brain scans may also help identifying new treatments and track the effectiveness of current antidepressant therapy and medications designed to help reduce abnormal protein build-up in the brain, the researchers said.

The team is planning larger studies involving investigators at UCLA and the University of Illinois that will address the impact of the genetic marker APOE-4, which is a risk factor for dementia and Alzheimer’s disease.

Source:  UCLA Newsroom release ,Archives of General Psychiatry

 

Researchers Discover Possible Key To Degenerative Nerve Diseases

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Researchers at the University of Wisconsin-Madison and collaborators have discovered a new protein in the eye of the fruit fly that may shed light on disorders in humans, such as Alzheimer’s disease, age-related macular degeneration, Huntington’s, Parkinson’s and other diseases related to nerve degeneration. All of these disorders may be linked to the malfunction of similar but yet-to-be-identified proteins in the human eye and brain.

In the fruit fly the new protein, which the scientists have named XPORT, is a molecular “chaperone” for two other important proteins that are key to sensory activities in the eye.

Rhodopsin is a protein that is responsible for absorbing light. The other protein, TRP, is a channel that plays a role in calcium influx into cells. XPORT guides these two proteins from the place where they are manufactured in the cell to the location where they do their jobs.

This intricate process of chaperoning includes synthesis, folding, assembly, quality control, transport and targeting of proteins to their appropriate locations, says senior author Dr. Nansi Jo Colley, a professor in the Department of Ophthalmology and Visual Sciences at the University of Wisconsin School of Medicine and Public Health. The complex process is prone to error, and a malfunction in any of the steps can have dire consequences in tissues.

“Accumulation of misfolded proteins often leads to severe pathology and cell death, producing blinding diseases and other neurodegenerative diseases,” says Colley, “Molecular chaperones are one of the first lines of defense in these fundamental processes.”

The team of researchers discovered XPORT while studying fruit flies with damaged retinas. Those with malfunctions in the function of XPORT displayed retinal degeneration and defects in rhodopsin and TRP, they found.

According to the researchers, XPORT forms a complex with rhodopsin and TRP and is required to successfully transport the two proteins to a specific location on the cell surface. Colley and the team of researchers also determined that XPORT is essential for cell survival. Mutations in XPORT prevented the two proteins from moving through the trafficking pathway and this ended in retinal degeneration and blindness in the fly.

TRP channels play a vital role as biological sensors, Colley said. They regulate calcium entering cells that are involved in vision, taste, olfaction, hearing and touch. “Defective TRP channels can cause night blindness in certain people,” Colley said.

XPORT was also found to interact closely with heat shock proteins, another family of molecular chaperones. “Heat shock proteins have also been implicated as agents that protect nerve cells from degeneration,” Colley says, “so XPORT or XPORT-like proteins might have therapeutic potential as well.”

Source: Neuron.

Chewing Gum for Your Health?

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Teachers have always been strict when it comes to chewing gum. Not only is it annoying to have kids chewing and popping their gum, they often discard it under their desks, or throw it on the floor. Next to an encounter with dog poop, stepping on gum is one of the worst shoe-related experiences.

But chewing gum has multiple uses. It temporarily freshens funky breath, and people often use chewing gum to help pop their ears when changing altitude, either in a vehicle traveling in a mountainous area, or in an airplane. Chewing gum (or swallowing the saliva that is generated) helps open the Eustachian tubes and allows painful, middle-ear air pressure to equalize. Years ago, a patient told me that chewing gum was worthless for this purpose. Much to my horror, she told me that the worst part was trying to get the gum out of her ears! She apparently was chewing it, and then inserting it in her ear canals like ear plugs.

Chewing gum typically has sugar, which can contribute to dental caries. Sugar-free gum is often distributed by parents for this very reason. The sorbitol in sugar-free gum has the potential to cause an increase in intestinal gas, however. Gum containing another naturally found sugar called xylitol, on the other hand, has some significant health benefits. Xylitol is used as a sweetener in many products, including mouthwash, toothpaste and medicines.

Xylitol is not only safe for diabetics because it does not trigger an insulin response; studies have found it beneficial in actually preventing dental caries. It is currently being studied as a preventative for osteoporosis and as a preventative for thrush (oral yeast infections).

I have read various studies that show that xylitol gum helps prevent middle-ear infections in children. Three Finnish studies, published in Cochrane Reviews, reported that “children who chewed gum containing xylitol had a 25% lower risk of developing middle ear infections.” The authors claim that xylitol inhibits the growth and acid production of certain bacteria, and they recommend two sticks of xylitol gum, chewed for five minutes, five times per day. That’s a lot of gum and a minimum of 8 grams of xylitol was recommended. So, is it safe?

Xylitol is safe (and natural for those who prefer natural remedies), but in doses over 65 grams, one small study of children found that several develop diarrhea and gas, though this potential side effect improved after several weeks of use.

There are dozens of brands of xylitol gum available, each containing about 1 gram of xylitol in each stick. It is not cheap – a hundred sticks cost from $10 to $12.  At 8-10 sticks a day, this preventative would cost about $30 a month. Is it cost effective? If you consider that dental care is not cheap, and a typical middle-ear infection can cost well over a hundred dollars without insurance, it well may be. But the idea of dozens of children chewing gum in class, sticking it to the bottom of their desks, or carelessly dropping it on the floor would not seem appealing to teachers.

So, next time a child is chastised for chewing gum in line, they can claim the gum is prescribed “medicine.”  Having a copy of these Finnish studies to whip out after arriving in the principal’s office.It would seem to help your legal defense.

Source: WebMD

The FDA Approves Eylea (Aflibercept) For Wet Macular Degeneration

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The U.S. Food and Drug Administration, on Friday, approved Eylea (aflibercept), also known as VEGF Trap-Eye, to treat patients with wet (neovascular) age-related macular degeneration (AMD), a leading cause of vision loss in Americans ages 60 and older.

There are currently four FDA approved treatments for AMD. A fifth treatment has not been approved by the FDA for AMD, but is approved for other conditions and is commonly used as an off-label AMD therapy. Like other treatments, Eyelea is injected into the eye, but studies have shown similar levels of effectiveness with less frequent doses. Patients treated with the new drug will receive injections every other month, rather than a once per month schedule recommended with the most commonly prescribed existing treatments. The drug’s manufacturer, Regeneron, believes the decrease in treatment frequency will mean fewer doctor’s visits, decreased cost, and greater convenience for the patient.

AMD gradually destroys a person’s sharp, central vision. It affects the macula, the part of the eye that allows people to see fine detail needed to do daily tasks such as reading and driving.

There are two forms of AMD, a wet form and a dry form. The wet form of AMD includes the growth of abnormal blood vessels. The blood vessels can leak fluid into the central part of the retina, also known as the macula. When fluid leaks into the macula, the macula thickens and vision loss occurs. An early symptom of wet AMD occurs when straight lines appear to be wavy.

“Eylea is an important new treatment option for adults with wet AMD,” said Edward Cox, M.D., M.P.H, director of the Office of Antimicrobial Products in FDA’s Center for Drug Evaluation and Research. “It is a potentially blinding disease and the availability of new treatment options is important.”

The safety and effectiveness of Eylea was evaluated in two clinical trials involving 2,412 adult patients. People in the study received either Eylea or Lucentis (ranibizumab injection). The primary endpoint in each study was a patient’s clearness of vision (visual acuity) after one year of treatment.

Eylea is injected into the eye either every four weeks or every eight weeks by an ophthalmologist. The studies showed that Eylea was as effective as Lucentis in maintaining or improving visual acuity. 

The most commonly reported side effects in patients receiving Eylea included eye pain, blood at the injection site (conjunctival hemorrhage), the appearance of floating spots in a person’s vision (vitreous floaters), clouding of the eye lens (cataract), and an increase in eye pressure.

Eylea should not be used in those who have an active eye infection or active ocular inflammation. Eylea has not been studied in pregnant women, so the treatment should be used only in pregnant women if the potential benefits of the treatment outweigh any potential risks. Age related macular degeneration does not occur in children and Eylea has not been studied in children.

Other FDA-approved treatment options for wet AMD include: Visudyne (verteporfin for injection) approved in 2000, Macugen (pegaptanib sodium injection) approved in 2004, and Lucentis (ranibizumab injection) approved in 2006.

Source: FDA and Regeneron