PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Bigger capsules may be long-sought key for transplanting islet cells

2015-05-18
(Press-News.org) Changing the size of cell-carrying spheres may surmount the difficulties that have bedeviled diabetes researchers trying to ferry insulin-producing islet cells into hosts as a way to treat type 1 diabetes.

New findings published in the journal Nature Materials suggest that for the spherical capsules, bigger may be better. Tiny gel capsules carrying islet cells allow insulin to seep out, and nutrients to get in, through microscopic holes. The holes are small enough, however, to isolate and protect the encapsulated cells from the cells of host's immune system, which would otherwise recognize them as foreign and destroy them. Encapsulating islet cells in a semi-permeable, biocompatible material has held promise for type 1 diabetes because it would eliminate the need to take lifelong immunosuppressive drugs. But the approach has been stymied in early clinical trials because scar tissue has formed on the surface of the capsules, choking off the flow of nutrients and oxygen to the islet cells inside.

The problem may be circumvented simply by increasing the size of the capsules, say the researchers. "This changes everything - this finding completely overturns what we thought about the biocompatibility of implantable spheres," said Dr. Jose Oberholzer, chief of transplantation surgery and director of cell and pancreas transplantation at the University of Illinois Hospital & Health Sciences System and an author on the paper.

"We always thought very small spheres were necessary for encapsulating cells, in order to minimize the diffusion distance for insulin to reach the bloodstream," Oberholzer said. Smaller spheres were also thought to minimize the formation of scar tissue. "But we now know that these small spheres are actually not nearly as biocompatible as larger spheres."

People with type 1 diabetes have an overactive immune system that destroys cells in islets of the pancreas that produce insulin, a hormone needed to convert sugars into usable energy. Patients must receive daily injections of insulin to compensate. Islet cells have been successfully transplanted to treat type 1 diabetes, but patients then must take immunosuppressive drugs to prevent destruction of the foreign cells. The new research, a collaboration led by scientists at the Massachusetts Institute of Technology, shows that spheres made of different biocompatible materials, 1.5 millimeters in diameter or larger - significantly bigger than the spheres used in previous clinical trials, which ranged from 0.1 to 1 millimeter in diameter - triggered lower levels of immune response in the host and developed less scar tissue on their surface.

In a series of experiments in which spheres of different sizes and materials were implanted into mice, and later into non-human primates, the immune system's scout cells, called macrophages, seemed almost to ignore spheres at least 1.5 millimeters in diameter, while smaller spheres were recognized and attacked.

In a mouse model of diabetes, animals treated with islet cells encased in 1.5 millimeter capsules maintained normalized blood glucose levels for up to 180 days -- five times longer than mice treated with 0.5 millimeter spheres. Using a specialized microfluidics device developed at the University of Illinois at Chicago under a grant from the National Institute of Diabetes and Digestive and Kidney Diseases, Oberholzer and his UIC colleagues delivered minute amounts of glucose into a tiny well containing encapsulated islet cells and measured the amount and movement of insulin excreted by the cells in real time. The UIC team showed that rat islet cells in 1.5 millimeter hydrogel spheres were able to sense glucose and respond by producing insulin with no significant delay in diffusion compared to cells in 0.5 millimeter spheres. The device was developed to evaluate the function of human islet cells by measuring the movement of not only insulin, but also calcium, which must first enter the cells in order for them to release their insulin. The device can measure extremely small amounts of insulin produced by just a handful of cells.

"The larger spheres don't pose a problem by slowing the speed of diffusion of glucose or insulin," Oberholzer said. "Just by increasing the size of the capsules used to carry insulin-producing cells, we show that the cells can be kept alive, perform their function, avoid destruction by the immune system, and seem to resist scar tissue buildup."

Oberholzer says the next step is to test the safety and efficacy of the larger spheres for islet-cell transplantation in clinical trials. "We have pegged encapsulated islet cells as a cure for type 1 diabetes for so long - but trials always end with the capsules engulfed in scar tissue and the cells dying," he said. "If we can get around this simply by increasing the size of the capsules, then we may have a viable cure for type 1 diabetes within reach."

INFORMATION:

Co-authors on the Nature Materials paper are Matthew Bochenek, Joshua Mendoza-Elias, Yong Wang and Merigeng Qi of UIC; Omid Veiseh, Joshua Doloff, Minglin Ma, Arturo Vegas, Hok Hei Tam, Andrew Bader, Jie Li, Erin Langan, Jeffrey Wyckoff, Whitney Loo, Siddharth Jhunjhunwala, Alan Chiu, Sean Siebert, Katherine Tang Stephanie Aresta-Dasilva, Danya Lavin, Michael Chen, Nimit Dholakia, Raj Thakrar, Robert Langer and Daniel Anderson of the Massachusetts Institute of Technology; Igor Lacik of the Polymer Institute of the Slovak Academy of Sciences; Gordon Weir of the Joslin Diabetes Center; and Dale Greiner of the University of Massachusetts Medical School in Worcester.

The work was supported by the Juvenile Diabetes Research Foundation grant 17-2007-1063, Leona M. and Harry B. Helmsley Charitable Trust Foundation grant 09PG-T1D027, National Institutes of Health grants EB000244, EB000351, DE013023 and CA151884, R01DK091526, Koch Institute Support (core) grant P30-CA14051 from the National Cancer Institute, and a gift from the Tayebati Family Foundation.



ELSE PRESS RELEASES FROM THIS DATE:

Pactamycin analogs offer new, gentler approach to cancer treatment

2015-05-18
CORVALLIS, Ore. -- Researchers at Oregon State University are pursuing a new concept in treatment of epithelial cancer, especially head and neck cancer, by using two promising "analogs" of an old compound that was once studied as a potent anti-tumor agent, but long ago abandoned because it was too toxic. The analogs are more highly selective than the parent compound, pactamycin, which originally was found to kill all cells, from bacteria to mammals, by inhibiting their protein synthesis. The pactamycin analogs, which were developed with biosynthetic engineering, also ...

Gender-science stereotypes persist across the world

2015-05-18
Largest study of its type shows people associate science with men in all 66 nations studied Dominance of men in science stereotypes strongest in Scandinavian countries, especially the Netherlands Gender-science stereotypes weaker in nations with more female scientists Interactive table providing comprehensive rankings for all 66 nations EVANSTON, Ill. --- The Netherlands had the strongest stereotypes associating science with men more than women, according to a new Northwestern University study that included data from nearly 350,000 people in 66 nations. These ...

Jumping spiders are masters of miniature color vision

Jumping spiders are masters of miniature color vision
2015-05-18
Jumping spiders were already known to see in remarkably high resolution, especially considering that their bodies are less than a centimeter long. Now, researchers reporting in the Cell Press journal Current Biology on May 18 have figured out how spiders in the colorful genus Habronattus see in three color "channels," as most humans do. "The eyes of jumping spiders could not be more different from those of butterflies or birds, and yet all three tune the color sensitivities using pigments that filter light," says Nathan Morehouse of the University of Pittsburgh. "It's ...

Signs of ancient earthquakes may raise risks for New Zealand

2015-05-18
Researchers have uncovered the first geologic evidence that New Zealand's southern Hikurangi margin can rupture during large earthquakes. The two earthquakes took place within the last 1000 years, and one was accompanied by a tsunami, according to the study published in the Bulletin of the Seimological Society of America (BSSA). The earthquakes took place roughly 350 years apart, according to the analysis by Kate Clark of GNS Science and colleagues. This may mean that the time between large earthquakes in this region is shorter than scientists have thought. The current ...

Study finds non-invasive colon cancer screening may be promising for African-Americans

2015-05-18
In a first-of-its-kind clinical trial, physician-scientists at University Hospitals (UH) Case Medical Center Seidman Cancer Center and Case Western Reserve University School of Medicine found that a new non-invasive technology for colon cancer screening is a promising alternative to colonoscopy for African Americans. The study recruited patients to compare the effectiveness of stool DNA (sDNA) testing with colonoscopy for detecting large colon polyps. SDNA is a test that detects colon cancer in its earliest stages, based on analysis of stool DNA. Developed in the laboratory ...

Academic medical centers at risk of a 'Kodak moment' if they fail to adapt

2015-05-18
(Philadelphia, PA) - Today's academic medical centers (AMCs) need to embrace the changing healthcare marketplace or run the risk of becoming the next Kodak - a former industrial giant that became obsolete when it failed to adapt to a shifting technological landscape. That is the premise of a commentary published this month electronically ahead of the print edition of Academic Medicine, the journal of the Association of American Medical Colleges. The commentary is authored by Verdi DiSesa, MD, MBA, Chief Operating Officer of the Temple University Health System (TUHS) and ...

How the immune system controls the human biological clock in times of infection

2015-05-18
PHILADELPHIA - An important link between the human body clock and the immune system has relevance for better understanding inflammatory and infectious diseases, discovered collaborators at the Perelman School of Medicine at the University of Pennsylvania and Trinity College, Dublin. In a study published this week in the Proceedings of the National Academy of Sciences, they report how a critical white blood cell called the macrophage, when exposed to bacteria, makes the biological clock inside the macrophage stop, allowing it to become inflamed. The complex mechanism they ...

Sleep apnea common among patients undergoing heart procedure

2015-05-18
ATS 2015, DENVER - Patients undergoing percutaneous coronary intervention (PCI), a coronary artery widening procedureused to treat heart disease, are at high risk for obstructive sleep apnea (OSA), according to new research presented at the 2015 American Thoracic Society International Conference. "Our findings, in a large, multicenter sample of patients, reinforce the known association between OSA and cardiovascular disease," said researcher Luciano Drager, MD, PhD, of the University of São Paulo School of Medicine in Brazil. "Nearly half of the patients in our ...

Adding genetic information to risk profile of smokers improves adherence to lung cancer screening

2015-05-18
Researchers have found that adding genetic information to a former or current smoker's clinical risk profile results in a reclassification of their risk for lung cancer in about one in four patients. Preliminary findings from their lung cancer screening feasibility study also suggests that those whose genetic and clinical risk placed them in the highest risk category were more likely to adhere to follow-up computed tomography (CT) scans during screening. The results of this study, conducted at El Camino Hospital in Mountain View, CA, follows on the heels of the National ...

Pulmonary rehabilitation helps patients newly diagnosed with obstructive sleep apnea

2015-05-18
ATS 2015, DENVER -- Pulmonary rehabilitation (PR) treatment could be a valuable addition to comprehensive therapy in patients with obstructive sleep apnea (OSA) syndrome, according to a new study. The study was presented at the 2015 American Thoracic Society International Conference. "In our study with 40 newly diagnosed OSA patients and a control group, pulmonary rehabilitation helped reduce body mass index, certain body circumferences, and improve pulmonary function," said researcher Katerina Neumannova, MSc, PhD, Palacky University, Faculty of Physical Culture, Olomouc, ...

LAST 30 PRESS RELEASES:

Pink skies

Monkeys are world’s best yodellers - new research

Key differences between visual- and memory-led Alzheimer’s discovered

% weight loss targets in obesity management – is this the wrong objective?

An app can change how you see yourself at work

NYC speed cameras take six months to change driver behavior, effects vary by neighborhood, new study reveals

New research shows that propaganda is on the rise in China

Even the richest Americans face shorter lifespans than their European counterparts, study finds

Novel genes linked to rare childhood diarrhea

New computer model reveals how Bronze Age Scandinavians could have crossed the sea

Novel point-of-care technology delivers accurate HIV results in minutes

Researchers reveal key brain differences to explain why Ritalin helps improve focus in some more than others

Study finds nearly five-fold increase in hospitalizations for common cause of stroke

Study reveals how alcohol abuse damages cognition

Medicinal cannabis is linked to long-term benefits in health-related quality of life

Microplastics detected in cat placentas and fetuses during early pregnancy

Ancient amphibians as big as alligators died in mass mortality event in Triassic Wyoming

Scientists uncover the first clear evidence of air sacs in the fossilized bones of alvarezsaurian dinosaurs: the "hollow bones" which help modern day birds to fly

Alcohol makes male flies sexy

TB patients globally often incur "catastrophic costs" of up to $11,329 USD, despite many countries offering free treatment, with predominant drivers of cost being hospitalization and loss of income

Study links teen girls’ screen time to sleep disruptions and depression

Scientists unveil starfish-inspired wearable tech for heart monitoring

Footprints reveal prehistoric Scottish lagoons were stomping grounds for giant Jurassic dinosaurs

AI effectively predicts dementia risk in American Indian/Alaska Native elders

First guideline on newborn screening for cystic fibrosis calls for changes in practice to improve outcomes

Existing international law can help secure peace and security in outer space, study shows

Pinning down the process of West Nile virus transmission

UTA-backed research tackles health challenges across ages

In pancreatic cancer, a race against time

Targeting FGFR2 may prevent or delay some KRAS-mutated pancreatic cancers

[Press-News.org] Bigger capsules may be long-sought key for transplanting islet cells