Archive for month: August, 2020

Computed tomography (CT) scans are one of the most frequently used imaging tools in medicine. In fact, more than 72 million scans are performed each year to diagnose various medical conditions. But public health concerns persist about radiation exposure from these tests

Researchers at University of California, San Diego School of Medicine and Shiley Eye Institute, with colleagues in China, have developed a new, regenerative medicine approach to remove congenital cataracts in infants, permitting remaining stem cells to regrow functional lenses.
The treatment, which has been tested in animals and in a small, human clinical trial, produced much fewer surgical complications than the current standard-of-care and resulted in regenerated lenses with superior visual function in all 12 of the paediatric cataract patients who received the new surgery.
In subsequent tests in animals with cataracts and in a small human trial, they found the new surgical technique allowed pre-existing LECs to regenerate functional lenses. In particular, the human trial involved 12 infants under the age of 2 treated with the new method and 25 similar infants receiving current standard surgical care. The latter control group experienced a higher incidence of post-surgery inflammation, early-onset ocular hypertension and increased lens clouding.

According to the American Heart Association, ischemic strokes account for nearly 90 percent of all strokes. They occur when a blocked artery prevents blood from getting to the brain and usually result in long-term disability or death. Now, a team of researchers led by the University of Missouri School of Medicine has developed a new, real-time method of imaging molecular events after strokes ― a finding that may lead to improved care for patients.

‘During an ischemic stroke, harmful enzymes called gelatinase become overactive in areas of the brain where blood flow is cut off, said Zezong Gu, PhD, an associate professor of pathology and anatomical sciences at the MU School of Medicine and lead author of the study. ‘Over-activation of these enzymes causes brain damage. Our team hypothesized that if we could visualize and track this activity in real-time, we could then work on developing a way to block the activity and prevent brain damage from occurring.’

Magnetic resonance imaging (MRI) is commonly used to diagnose strokes because it produces precise, sectional images of the brain. Although these images can verify the region of arterial blockages within the brain, current contrast agents are not specific or sensitive enough to reveal important molecular events, such as gelatinase activity, on an MRI image.

To overcome this obstacle, the researchers used peptides that specifically recognize gelatinase activity. The peptides were tagged with contrast agents through a process developed by research team member Roger Tsien, PhD, a biochemist and Nobel Laureate at the University of California, San Diego.

‘Once the tagged peptides travelled to the site of increased gelatinase activity, they were absorbed into the cells with this activated enzyme,’ Gu said. ‘When enough of these peptides were absorbed, the stroke site was visible on an MRI. We tested this technique in both cell-based and mouse models of ischemic stroke. Using this method, we successfully tracked gelatinase activity.’

Gu suggests that real-time imaging of this activity could lead to a better understanding of how to treat strokes and mediate the damage they cause.

‘Our findings indicate that tagged peptides can be used as a non-invasive probe to detect and track gelatinase activity,’ Gu said. ‘This process may serve as an additional tool for clinicians to treat their patients if a viable inhibitor can be developed to prevent the damage caused by this activity.’

Gu and his team currently are working to develop such a gelatinase inhibitor. University of Missouri

The lab of Patrick Aebischer at EPFL has developed a bioactive capsule containing cells that have been genetically engineered to produce antibodies against Abeta. The capsule is implanted in the tissue under the skin, and over time the cells produce and release a steady flow of antibodies into the bloodstream, from where they cross over into the brain to target the Abeta plaques.
Before going into capsule, the cells are first genetically engineered to produce antibodies that specifically recognize and target Abeta. The cells of choice are taken from muscle tissue, and the permeable membranes let them interact with the surrounding tissue to get all the nutrients and molecules they need.

EPFL