October 2, 2009 (Newswise) - South Dallas residents are 30 percent more likely to be admitted to a hospital due to diabetes or a diabetes-related condition than other city residents. In fact by 2010, 13 percent of those living in South Dallas will be diabetic.Baylor Health Care System is reaching out to the traditionally underserved neighborhood, transforming a local recreation center into the area's first and only diabetes health and wellness institute. Baylor will invest $15 million in the project with the mission of saving lives through improved diabetes care, education and research. The new institute is expected to open in Spring 2010.

The focus of the Diabetes Health and Wellness Institute at Juanita J. Craft Recreation Center (Institute) will not only be on treatment, but prevention as well.

The Institute will provide:

• Full-time, on-site physician and nurse practitioner*
• Visiting medical specialists*
• Referral coordinator for specialty and ancillary care
• Diabetes management educator
• Affordable diabetes medications
• Nutrition and healthy cooking classes
• Exercise programs including running and walking clinics and weight training

MORE ABOUT DIABETES IN TEXAS:

• According to the Texas Diabetes Council, the prevalence of diabetes in Texans (18 and older) rose to 10.3 percent in 2007
• More than 1.8 million adults in Texas are diabetic, 460,000 are believed to be undiagnosed
• Diabetes is slightly more common in women than men (10.8 percent vs. 9.9 percent)
• Diabetes rates are higher among African Americans (12.9 percent), Hispanics (12.3 percent) and other minorities (11.8 percent) than Whites (8.5 percent)
• The prevalence of diabetes increases with age (2.7 percent for people under 30, 32.2 percent for people 65 and older)
• Diabetes rates decrease as education levels increase (15.8 percent among those without a high school diploma, 6.9 percent among those who attended college)
• One of every five health care dollars is spent caring for someone with diagnosed diabetes

October 1, 2009 (EurekAlert) - A new study reports that transplanted pigment-containing visual cells derived from human embryonic stem cells (hESCs) successfully preserved structure and function of the specialized light-sensitive lining of the eye (known as the retina) in an animal model of retinal degeneration. The findings, published by Cell Press in the October 2nd issue of the journal Cell Stem Cell, represent an exciting step towards the future use of cell replacement therapies to treat devastating degenerative eye diseases that cause millions of people worldwide to lose their sight.The retinal pigment epithelium (RPE) is a layer of pigmented cells sandwiched between the visual retinal cells, called photoreceptors, and the nourishing blood vessels at the back of the eye. The RPE provides essential support to the retinal photoreceptors and is critical for normal vision. Deterioration of the RPE plays a central role in the progression of diseases such as age-related macular degeneration and sub-types of retinitis pigmentosa. These conditions are associated with a progressive loss of vision that often leads to blindness.

"Although there are a variety of therapeutic approaches under development to delay the degenerative process, the grim reality is that many patients eventually lose their sight," explains Dr. Benjamin Reubinoff, a senior author of the study. "Cell therapy to replenish the degenerating RPE cells may potentially halt disease progression." Dr. Reubinoff and Dr. Eyal Banin who led the study, with their colleagues from Hadassah-Hebrew University Medical Center in Jerusalem, developed conditions to guide hESCs to differentiate into functional RPE-like cells in the laboratory.

The researchers found that nicotinamide (vitamin B3, NIC) and Activin A, an important growth factor, promoted differentiation of hESCs towards an RPE fate. The hESC-derived RPE-like cells, which could be identified by their characteristic black pigment, exhibited multiple biological properties and genetic markers that define authentic RPE cells. Further, the cells successfully delayed deterioration of retinal structure and function when they were transplanted into an animal model of retinal degeneration caused by RPE dysfunction.

Taken together, the results demonstrate that NIC and Activin A promoted the differentiation of hESCs towards an RPE fate. The hESC-derived cells exhibited the defining characteristics associated with RPE and successfully rescued the retina when transplanted into an animal model of retinal degeneration. "Our findings are an important step towards the potential future use of hESCs to replenish RPE in blinding diseases," concludes Dr. Banin.

September 23, 2009 (EurekAlert) - MIT engineers have designed a retinal implant for people who have lost their vision from retinitis pigmentosa or age-related macular degeneration, two of the leading causes of blindness. The retinal prosthesis would help restore some vision by electrically stimulating the nerve cells that normally carry visual input from the retina to the brain.Why it matters: The chip would not restore normal vision but could help blind people more easily navigate a room or walk down a sidewalk. "Anything that could help them see a little better and let them identify objects and move around a room would be an enormous help," says Shawn Kelly, a researcher in MIT's Research Laboratory for Electronics and member of the Boston Retinal Implant Project.

How it works: Patients who received the implant would wear a pair of glasses with a camera that sends images to a microchip attached to the eyeball. The glasses also contain a coil that wirelessly transmits power to receiving coils surrounding the eyeball. When the microchip receives visual information, it activates electrodes that stimulate nerve cells in the areas of the retina corresponding to the features of the visual scene. The electrodes directly activate optical nerves that carry signals to the brain, bypassing the damaged layers of retina.

Next steps: The research team, led by John Wyatt, MIT professor of electrical engineering and computer science, recently reported a new prototype that they hope to start testing in blind patients within the next three years, after some safety refinements are made. Once human trials begin and blind patients can offer feedback on what they're seeing, the researchers will learn much more about how to configure the algorithm implemented by the chip to produce useful vision.

September 23, 2009 (Newswise) - The Endocrine Society announced today its support for Representative Carolyn McCarthy's (D-NY) Food Marketing in Schools Assessment Act (H.R 3625). The bill, which was first introduced in July 2007, calls for an in-depth study of the nutritional value of foods and drinks marketed in middle and high schools, as well as the vehicles advertisers use to reach young consumers in our nation's schools."Children are exposed to advertisements on billboards, scoreboards, soft drink machines and posters on a daily basis. Such marketing tactics may lead to poor food choice decisions," said Robert Vigersky, MD, president of The Endocrine Society. "This study will provide insight for policy makers, parents and school administrators to determine whether the messages directed at school children lead to unhealthy choices and if policies need to be changed. The Society supports prevention strategies aimed at lowering the prevalence of childhood obesity in our nation and around the world."
According to a 2006 Arizona State University national survey of district public school officials, 67 percent of district public schools allowed advertising by corporations selling foods of minimal nutritional value or foods high in fat and sugar. In 2005, a California Endowment-funded study of 20 California public schools found that 60 percent of the in-school posters/signage advertised food and beverage products high in fat, trans fat, sugar and sodium to students.
Specifically, the McCarthy Bill:

• Directs the Secretary of Education to study and report to the Congress on the marketing of food and beverages in middle and high schools;
• Requires the study to assess the nutritional quality of foods, the media through which they are marketed to children in schools, and mechanisms that regulate marketing; and
• Directs the Secretary of Education to collaborate in the conduct of the study with the Division of Adolescent and School Health of the Centers for Disease Control and Prevention.

August 19, 2009 (EurekAlert) - Good news for people fearful of needles and squeamish of shots: Scientists at the 238th National Meeting of the American Chemical Society report the design of a painless patch that may someday render hypodermic needles - as well as annual flu shots - a thing of the past. Lined with tiny "microneedles," these patches could make treatment of diabetes and a wide range of other diseases safer, more effective and less painful. Used as tiny hypodermic needles, they could improve treatment of macular degeneration and other diseases of the eye.
"It's our goal to get rid of the need for hypodermic needles in many cases and replace them with a patch that can be painlessly and simply applied by a patient," says Mark Prausnitz, Ph.D. "If you can move to something that's as easy to apply as a band-aid, you've now opened the door for people to self-administer their medicine without special training."

Prausnitz says that advances in the electronics industry in microfabricating very small objects like transistors enabled the development of microneedles. "We've built off those technological advances to address a need in medicine," he explains. "We're trying to bring the two worlds together." Each needle is only a few hundred microns long, about the width of a few strands of human hair.

Prausnitz and his colleagues at the Georgia Institute of Technology suggest that the microneedle patch could, for instance, replace yearly trips to the doctor for flu shots.

"Although it would probably first be used in a clinical setting, our vision is to have a self-administered flu vaccine patch. So instead of making an appointment with your doctor to get your flu shot, you can stop by the pharmacy or even get a patch in the mail and self-apply. We think that could very much increase the vaccine coverage since it would be easier for people to be vaccinated," Prausnitz explains.

In a collaboration with Emory University, Prausnitz and his team administered flu vaccines via conventional injections and microneedle patches in mice. After exposing the mice to the flu, they compared the resulting immune response and antibody levels. They found that the antibody levels were the same by either route. Taking a closer look, they discovered that microneedle delivery resulted in a better protective immune response by other measures.

"Toward the goal of a flu vaccine patch, we are continuing the animal studies, but we're also working toward our first human trial, which we hope to do in 2010," Prausnitz says.

Microneedles are not just able to deliver drugs through the skin - they can also be used for targeted drug delivery in the eye. They may help create an improved treatment for macular degeneration, the leading cause of blindness in the United States.

In recent years, macular degeneration has become treatable thanks to new drugs that halt and partially reverse the disease. The new drugs are a victory for the millions of patients suffering macular degeneration, but the treatment is not pleasant - the drugs must be injected directly into the eye every month.

"For the squeamish there are obvious drawbacks, but more importantly, there are real safety concerns about that kind of repeated injection into the eye. With a microneedle, we can still do the same kind of concept, injecting something into the eye, but we can now do it with a very short needle that doesn't penetrate all the way in," says Prausnitz, adding that "no one else is working on microneedle-based drug delivery to the eye."

He notes that microneedle treatments of the eye can target specific tissues in the eye. "In localizing the delivery, microneedle treatments for macular degeneration and other diseases of the eye may prove safer than conventional needles. We're now doing experiments with rabbits and non-human primates - we hope to have the first human trial in the next few years," says Prausnitz.

August 18, 2009 (EurekAlert) - Elevated levels of the enzyme arginase contribute to vascular eye damage and Medical College of Georgia researchers say therapies to normalize its levels could halt progression of potentially blinding diseases such as diabetic retinopathy.
Their work, published in the August issue of The American Journal of Pathology, is the first to make the connection between eye disease and arginase, an enzyme known to be a player in cardiovascular disease, according to researchers at MCG and Charlie Norwood Veterans Affairs Medical Center.

"The goal is to find a new strategy for preventing progression of diabetic retinopathy," says Dr. Ruth Caldwell, a cell biologist at the MCG School of Medicine and VA Medical Center, and the study's corresponding author.

Because they could measure arginase levels in the blood, it also could become a biomarker for a disease process that can work silently in the eye for months or even years, she says.

More broadly, understanding just how arginase regulates inflammation should lead to new therapies for many acute and chronic inflammatory diseases in the eyes and other organs, says Dr. Wenbo Zhang, postdoctoral fellow in Dr. Caldwell' lab and the paper's first author.

The researchers suspect an elevated arginase level is a red flag of early vascular damage in the eyes as well as the heart, kidneys and other organs. "We don't think this is going to be specific to the retina," Dr. Caldwell says, noting that inflammation often precedes full blown vascular disease.

"We know that people with diabetes have a greater incidence of heart attack and we know that vision is a sense that suffers greatly in diabetes," says Dr. R. William Caldwell, study co-author who chairs the Department of Pharmacology and Toxicology in the MCG School of Medicine. "We are finding arginase is a common player."

To create an animal model of the inflammation that occurs early in vascular eye disease, they used bacterial proteins to produce a severe and rapid inflammation of the eye called uveitis, which can also cause blindness but is easier to detect and treat than diabetic retinopathy.

"Inflammation of the blood vessel walls in the retina is some of the earliest eye damage that occurs in diabetes. This is like hitting the same system with a sledge hammer," Dr. Ruth Caldwell says. Short term, inflammation causes redness and irritation as it lays the groundwork for an unhealthy remodeling of blood vessel walls that restricts blood flow.

Inside the diabetic eye, high glucose levels trigger inflammation and, in an apparent effort to fight it, arginase actually ends up contributing to inflammation and vascular disease as well. The crux of the problem seems to be too much competition for L-arginine, an amino acid arginase requires to take any action - good or bad, says Dr. William Caldwell.

The retina, located at the back of the eye, is essentially an extension of the brain that receives light and transforms it to a neural impulse that travels back to the brain via the optic nerve. It can withstand assaults, such as elevated glucose levels that occur in diabetes, for years before vascular cells become damaged and die. That destruction spurs development of new blood vessels to deliver oxygen to oxygen-starved tissue but instead the proliferation blocks vision and they leak, increasing retinal damage.

Early in the diabetic process, high levels of glucose trigger high levels of inducible nitric oxide synthase, which makes nitric oxide. Under conditions of acute inflammation, nitric oxide helps control injury by killing off invaders. But during diabetes, it increases oxidative stress, causing further tissue damage. As part of the fight, arginase increases to provide substrates for tissue repair and to dampen the actions of inducible nitric oxide synthase. The complicating news is that nitric oxide synthase in endothelial cells, which makes the nitric oxide that enables blood vessels to relax, also is competing with arginase for the L-arginine.

The net effect can be too little nitric oxide inside blood vessel walls to help them relax and keep white blood cells and platelets from sticking to them.

"It's taking L-arginine away from the nitric oxide synthase so it can accelerate wound healing but the lack of substrate for nitric oxide synthase leads to vascular constriction and occlusion which causes further tissue damage, " Dr. Ruth Caldwell says. The researchers, who also are studying this process in a model of diabetic retinopathy, want to fully delineate the complex scenario. They already know high levels of the signaling molecule reactive oxygen species is another factor. As with arginase, some reactive oxygen species formation is a good thing but too much causes blood vessel damage.

"Our studies demonstrate that if we inhibit arginase, we also reduce the reactive oxygen species level and vice versa," Dr. Zhang says. "It appears that arginase and nitric oxide synthase influence each other in a positive feedback loop."

Rather than drugs that generally suppress arginase, the researchers want to find new drugs that can restore healthy levels of arginase. "You need arginase. If you don't have it, you are in big trouble," says Dr. William Caldwell. "We want to delineate the events that cause elevation and limit the elevation to prevent the resulting pathology."

The only U.S. Food and Drug Administration approved therapy to intervene in diabetic retinopathy is to use lasers to burn holes in the retina, which reduces the oxygen needs of the tissue by destroying some of it.

In related studies, Dr. William Caldwell, in conjunction with Dr. Maritza Romero, MCG assistant research scientist, has shown that in diabetes blood vessels throughout the body suffer from too much competition for L-arginine and that another amino acid, L-citrulline, as well as statin drugs used to treat cholesterol can prevent unhealthy elevation of arginase.

July 31, 2009 (EurekAlert) - This month's Ophthalmology, the journal of the American Academy of Ophthalmology, reports on use of bevacizumab (Avastin), to benefit diabetic patients with macular edema as well as people who develop cystoid macular edema after cataract surgery. Bevacizumab is also used to treat some cancers. Another study describes methods that could make cataract surgery safer for diabetic retinopathy (DR) patients. DR is the major threat to vision in working-age people, a problem that will only intensify if cases triple by 2050 as predicted.New Treatment Succeeds after Laser Fails in Diabetic Patients; Treatment also Controls Cystoid Macular Edema after Cataract Surgery

DR damages the light-sensitive retina at the back of the eye, the area that transmits images to the optic nerve. In type 2 diabetes patients, retinopathy vision loss most often results from macular edema (DME), swelling and thickening of the macula in the retina's center. Laser treatment is usually able to reduce vision loss, but widespread, diffuse DME (DDME) is often resistant to laser and other standard treatments.

Treating DMME with bevacizumab (Avastin), an anti-vascular endothelial growth factor (anti-VEGF) medication that inhibits abnormal blood vessels, was studied in115 patients (139 eyes) by the Pan-American Collaborative Retina Study Group, led by J. Fernando Arevalo, MD, of the Caracas Central Ophthalmologic Clinic, Venezuela. Within one month of the initial intravitreal bevacizumab (IVB) injections, improvement could be detected. By the end of the 24 month follow-up period vision had improved in 51.8 percent of eyes, and 97.1 percent of eyes were either stable or improved. No serious adverse effects occurred.

The Pan-American Collaborative Retina Study Group also reviewed the use of bevacizumab in patients with post-cataract surgery cystoid macular edema (CME) who had not responded to standard treatment. Twenty to 30 percent of all cataract surgery patients develop CME, in which the macula swells as fluid-filled cysts form. Usually the condition resolves without treatment and causes no permanent vision loss, but in a small percentage of patients vision remains worse than 20/40 and treatment is needed. Standard treatments include steroids, non-steroidal anti-inflammatories (NSAIDs), other medications, or surgery.

The researchers reviewed the records of 31 patients (36 eyes) who were treated with at least one IVB injection and followed for 12 months between 2005 and 2007. At the study's outset the mean best-corrected visual acuity was 20/200, and at 12 months the mean was 20/80. Most eyes (72.2 percent) improved and the rest remained stable (27.8 percent). Macular thickness also decreased in most eyes. Patients who received two or more injections were significantly more likely to improve. No adverse systemic or vision side effects or outcomes were reported.

"Large, randomized controlled clinical trials are needed to confirm IVB's efficacy and safety in treating these conditions," Dr. Arevalo said. "The results for DMME are very promising and suggest that combining anti-VEGF treatment with laser therapy may prove useful." He added, "Also, once further study is completed, unresolved CME post-cataract surgery should be considered for inclusion as an indication for use of IVB." "

Extra Precautions Needed with Cataract Surgery for DR Patients

Before 1996, retinopathy often developed or progressed rapidly in diabetic patients following cataract surgery. In the past decade the less-invasive phacoemulsification method has reduced cataract surgery complications in general, but the impact on diabetic retinopathy has been unclear. A clinic-based cohort study (2004 to 2006) led by Jie Jin Wang, MMed, PhD, at the Centre for Vision Research, University of Sydney, Australia, followed 169 diabetic patients aged 65 years and older for 12 months post-cataract surgery. Forty-five of these patients had surgery in just one eye.

Overall, DR developed or progressed in about one-third of operated eyes compared with about one-fifth of non-operated eyes. In the 45 patients for whom fellow eye comparisons were made, DR progressed in 35.6 percent of operated eyes versus 20 percent of non-operated eyes. Research on older cataract surgery methods had reported DR progression in 37 to 38 percent of eyes within 12 to 18 months of surgery; phacoemulsification is somewhat less likely to stimulate DR progression, the new study suggests. Dr. Wang cautions that patients who need cataract surgery may simply be at greater risk for DR progression, because both conditions are related to poor control of diabetes. Cataract may be a marker for greater DR severity or increased risk of progression.

"Although our results should not argue against cataract surgery in older people with diabetes, clinicians need to recognize the DR risk, treat active DR preoperatively-for example, use laser treatment to control macular edema¬-and closely monitor diabetes and DR after cataract surgery," Dr. Wang said.

July 30, 2009 (EurekAlert) - Short-term complications and death rates were low following bariatric surgery to limit the amount of food that can enter the stomach, decrease absorption of food or both, according to the Longitudinal Assessment of Bariatric Surgery (LABS-1). The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. Results are reported in the July 30 issue of the New England Journal of Medicine.
Less than 1 percent (0.3 percent) of patients died within 30 days of surgery, further supporting the short-term safety of bariatric surgery as a treatment for patients with extreme obesity.

Bariatric surgery can have dramatic health benefits--such as improved blood sugar control or even reversal of type 2 diabetes. But it also carries serious risks, including death. The LABS-1 study aimed to evaluate the short-term safety of bariatric surgery to help doctors and patients understand the risks.

"Evaluating the 30-day safety outcomes of bariatric surgery in large populations is an essential step forward," according to co-author Myrlene Staten, M.D., senior advisor for diabetes translation research at NIDDK, part of NIH. "And LABS-1 data are from all patients who had their procedure performed by a surgeon participating in the study, not from just a select few patients."

Various types of bariatric surgery limit food intake, nutrient absorption or both. The major types of surgery undergone by participants in this study included laparoscopic adjustable gastric banding, laparoscopic Roux-en-Y gastric bypass and open Roux-en-Y gastric bypass. Gastric bands create a pouch around the top of the stomach to limit food intake at any one time. Gastric bypass also creates a pouch and redirects food around most of the stomach and part of the small intestine, limiting the absorption of food..

The LABS-1 consortium followed 4, 776 patients who had bariatric surgery for the first time, evaluating complications and death rates within the first 30 days after surgery. Patients were at least 18 years old and had an average body mass index (BMI) of 44, considered extremely obese. BMI measures weight in relation to height. As with most populations undergoing bariatric surgery, the majority of LABS-1 patients were white and female. The study took place over two years at 10 medical sites, with one additional center coordinating data collection and analyses.

Within 30 days of surgery, 4.1 percent of patients had at least one major adverse outcome, defined as death, development of blood clots in the deep veins of the legs or in the pulmonary artery of the lungs, repeat surgeries, or failure to be discharged from the hospital within 30 days of surgery.

Thirty day mortality was low, ranging from no deaths in the laparoscopic adjustable gastric band group, to six (0.2 percent) in the laparoscopic Roux-en-Y gastric bypass group, to nine (2.1 percent) in those undergoing open Roux-en-Y gastric bypass. The overall risk of complications also varied by procedure.

The investigators pointed out, however, that people undergoing some procedures, such as open Roux-en-Y gastric bypass, tended to be heavier and sicker than those undergoing laparoscopic adjustable gastric banding, and after adjusting for patient and center characteristics, there were no significant differences in complication risk that could be attributed to the type of procedure. There were some patient factors that increased the risk of complications, including a preoperative history of deep vein blood clots and sleep apnea. Patients with a very high BMI, a measure that relates weight to height, were also at increased risk--those with a BMI of 75 had a 61 percent higher risk of complications than those with a BMI of 53.

Currently, more than one third of U.S. adults are obese (BMI higher than 30) and an increasing number are extremely obese (BMI higher than 40), according to the U.S. Centers for Disease Control and Prevention. People who are extremely obese are potential candidates for bariatric surgery.

"There is a real need to determine safe and effective treatments for patients with extreme obesity and its associated medical conditions," said Susan Z. Yanovski, M.D., a co-author of the paper and co-director of NIDDK's Office of Obesity Research. "This study's results can help patients and physicians make informed decisions about potential risks and benefits of bariatric surgery."

April 8, 2009 (EurekAlert) - Measuring kidney function by assessing two different factors-glomerular filtration rate (GFR) and urinary albumin levels-helps determine which patients with chronic kidney disease (CKD) will develop end-stage renal disease (ESRD), according to a study appearing in the May 2009 issue of the Journal of the American Society Nephrology (JASN). This combination test could help physicians identify patients at high risk of serious kidney trouble and allow them to intervene at an early stage.While there is a high prevalence of CKD worldwide, relatively few individuals with the disease develop ESRD, expected to affect 785,000 people in the U.S. by 2020 (current annual cost: $32 billion). Physicians and researchers have looked for ways to identify which patients will progress to ESRD in order to target patients most in need of extensive treatment, and help establish clinical guidelines and public health plans for treating patients with CKD.

Stein Hallan, MD, PhD (St. Olav University Hospital, Norway), and his colleagues recently conducted a study to see if combining two tests commonly used to measure kidney function might help predict ESRD. One test measures an individual's estimated glomerular filtration rate (eGFR-a measure of the volume of fluid filtered by the kidneys), while the other measures the amount of albumin (the predominant protein in the blood) that is excreted in urine. A high urinary albumin level indicates a rapid rate of kidney disease progression, and a low eGFR indicates an advanced stage of disease.

The researchers analyzed data from 65,589 adults who participated in the population-based Nord-Trøndelag Health (HUNT 2) Study and found 124 individuals who developed ESRD after more than 10 years of follow-up. Combining urinary albumin and eGFRs results identified more than 65% of patients who would develop this condition. Other factors such as hypertension, diabetes, smoking, obesity, and cardiovascular disease did not provide any additional information that could be used to predict who would develop ESRD.

"We provide clear evidence… that reduced eGFR should always be complemented by information on urine-albumin to yield optimal prediction of the risk of progression to ESRD," said Dr. Hallan. He added that combining these measurements might also help reduce the number of patients referred to specialists without losing the ability to detect future ESRD cases.

"Future risk scores and classification systems based on these two variables will be a simple and powerful tool for improving our ability to efficiently handle the large group of patients with CKD," the authors wrote.

April 7, 2009 (EurekAlert) - Scientists at Schepens Eye Research Institute have found that the growth factor known as TGF-β is essential to the health of blood vessels in the retina and that blocking it can cause retinal dysfunction. These findings, published in the April 2 issue of PLoS ONE, may have an important impact on the prevention and treatment of diseases such as diabetic retinopathy and macular degeneration."These results are significant because they add to our understanding of the molecules that help to maintain blood vessels in a healthy state," says Patricia D'Amore, PhD, senior scientist at Schepens and principal investigator of the study, who adds that this information may be useful in understanding the changes that occur in the retinal microvasculature prior to the development of proliferative diabetic retinopathy.

"Insight into the role of this growth factor may also help clinicians monitor the use of systemic drugs targeting TGF-β, which is elevated in a number of conditions (such as cancer and fibrotic diseases) to limit any vision problems that might occur as a side effects." adds Tony Walshe, PhD, the first author of the study and a Postdoctoral Fellow in the D'Amore's laboratory team.

Capillaries are the smallest blood vessels in the body and the site at which oxygen and nutrients are transferred from the blood to the tissues. A capillary is composed of an endothelial cell, which forms the lining of the small tube, and a pericyte, which wraps around the outside of the tube. Scientists have long believed that communication between these two cell types is necessary to maintain blood vessel structure and function.

According to Walshe, the goal of the PLoS ONE study was to determine if TGF-β plays a role in keeping blood vessels functioning normally. In previous experiments using tissue cultures, the D'Amore laboratory had identified TGF-β as a protein that results from the communication between the two cell types and which they use to maintain the health of the small blood vessels. In the current study, the team wanted to confirm that finding in animals.

To do that, they injected mice with a virus that produces large quantities of soluble endoglin, a protein that would circulate, and then bind to and inhibit TGF-β. When they examined the retinas of treated mice, the team found clear evidence that retinal blood vessels were losing their integrity-blood was not moving efficiently through the smaller vessels into the retina tissue, and fluid was leaking out of the vessels, which does not happen when the vessels are functioning properly. These defects led to the death of ganglion cells (nerve cells in the innermost part of the retina) and a loss of visual function.

According to D'Amore and Walshe, the demonstration of the role played by TGF-β is one more piece of a very complex set of controls that keeps blood vessels and the retina healthy.

Future studies are aimed at exploring what other molecules are involved in maintaining healthy blood vessels and how these relate to the development of microvascular diseases.