New patches made with human cells help boost recovery from heart attack

Agencies
January 13, 2018

Washington, Jan 13: A research has been conducted to enhance recovery from heart attack.For the first time, large human cardiac-muscle patches have been tested in the lab on large animals in a heart attack model. It showed that it resulted in improved recovery from heart attack injury.

This is the first large-animal study of muscle patches carried with a goal of treating human heart attacks by suturing cardiac-muscle patches over a specific area of dead heart muscles. It was carried out in order to reduce the pathology that often leads to heart failure.

The research was conducted by Jianyi `Jay` Zhang, from University of Alabama at Birmingham Biomedical Engineering, a joint department of the UAB School of Medicine and the UAB School of Engineering.Each patch is 1.57 by 0.79 inches in size and nearly as thick as a dime.

Zhang and colleagues found that transplanting two of these patches onto the infarct area of a pig heart significantly improved the function of the heart`s left ventricle, the major pumping chamber.

The patches also significantly reduced infarct size, which is the area of dead muscle; heart-muscle wall stress and heart-muscle enlargement; as well as significantly reducing apoptosis, or programmed cell death, in the scar border area around the dead heart muscle.Furthermore, the patches did not induce arrhythmia in the hearts, a serious complication observed in some past biomedical engineering approaches to treat heart attacks.

A mixture of three cells - two million endothelial cells - known to help cardiomyocytes function and survive in a micro-environment, 2 million smooth muscle cells - known to line blood vessels, and 4 million cardiomyocytes - known as heart-muscle cells, each patch is grown in a 3-D fibrin matrix.

Subsequently, it is rocked back and forth for a week and all cells start to beat synchronously after day one.The three cell types are differentiated in the making from cardiac-lineage human-induced stem cells, also known as hiPSCs.

Dynamic rocking and the apt mixture produce more quantity of mature heart-muscles cells, with more contractive force and superior physiological function, as compared to patches made with mono-layered cells which are not dynamically rocked.

In the past, attempts to use hiPSCs to treat large animal models of heart attacks have shown very low rates of engraftment or survival. The current research shows a relatively higher rate of engraftment - 10.9 percent - after four weeks of transplant which resulted in improved heart recovery.

These patches also release tiny blebs called exosomes which carry RNA and proteins from one cell to other. In tissue culture experiments, it is found that such exosomes which are released from large heart-muscle patches help in the survival of heart-muscle cells.

Additionally, these patches are found to reverse or prevent detrimental changes in protein phosphorylation in the sarcomeres of heart-muscle tissues bordering the infarct of the heart. This result suggested that hiPSC-derived heart cells may improve contractile function after heart attacks.

The research was conducted by the University of Alabama at Birmingham.

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Agencies
July 4,2020

The Union health ministry on Friday revised the dosage of anti-viral drug remdesivir to be administered to coronavirus patients in the moderate stage of illness from the earlier six days to five days as it issued an updated 'Clinical Management Protocols for COVID-19'.

The drug, administered in the form of injection, should be given at a dose of 200 mg on day one followed by 100 mg daily for four days (total five days), the new treatment protocols stated.

The Health Ministry on June 13 had allowed the use of remdesivir for restricted emergency use in moderate cases under "investigational therapies".

"Under emergency use authorisation, remdesivir may be considered for patients in moderate stage requiring oxygen support," the document stated.

It is not recommended for those with severe renal impairment and high level of liver enzymes, pregnant and lactating women, and those below 12 years, it said.

The ministry also okayed off-label application of tocilizumab, a drug that modifies the immune system or its functioning, and convalescent plasma for treating COVID-19 patients in the moderate stage of illness as "investigational therapies".

It also recommended hydroxychloroquine for patients during the early course of the disease and not for critically-ill patients.

On June 27, the ministry had included an inexpensive, widely used steroid dexamethasone in treatment protocols for COVID-19 patients in the moderate to severe stages of their illness among other therapeutic measures.

The ministry advised use of dexamethasone, which is already used in a wide range of conditions for its anti-inflammatory and immunosuppressant effects, as an alternative choice to methylprednisolone for managing moderate to severe cases of coronavirus infection.

India's COVID-19 cases soared by over 20,000 in a day for the first time taking the country's total tally to 6,25,544 on Friday while the death toll climbed to 18,213 with 379 new fatalities, according to the Union Health Ministry data updated at 8 am.

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Agencies
June 22,2020

A team of scientists has produced first open source all-atom models of full-length COVID-19 Spike protein that facilitates viral entry into host cells – a discovery that can facilitate a faster vaccine and antiviral drug development.

The group from Seoul National University in South Korea, University of Cambridge in the UK and Lehigh University in the US produced the first open-source all-atom models of a full-length S protein.

The researchers say this is of particular importance because the S protein plays a central role in viral entry into cells, making it a main target for vaccine and antiviral drug development.

"Our models are the first full-length SARS-CoV-2 spike (S) protein models that are available to other scientists," said Wonpil Im, a professor in Lehigh University.

"Our team spent days and nights to build these models very carefully from the known cryo-EM structure portions. Modeling was very challenging because there were many regions where simple modeling failed to provide high-quality models," he wrote in a paper published in The Journal of Physical Chemistry B.

Scientists can use the models to conduct innovative and novel simulation research for the prevention and treatment of Covid-19.

Though the coronavirus uses many different proteins to replicate and invade cells, the Spike protein is the major surface protein that it uses to bind to a receptor.

The total number of global COVID-19 cases was nearing 9 million, while the deaths have increased to over 467,000, according to the Johns Hopkins University.

With 2,279,306 cases and 119,967 deaths, the US continues with the world's highest number of COVID-19 infections and fatalities, according to the CSSE.

Brazil comes in the second place with 1,083,341 infections and 50,591 deaths.

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Agencies
May 25,2020

Singapore, May 25: COVID-19 patients are no longer infectious after 11 days of getting sick even though some may still test positive, according to a new study by infectious disease experts in Singapore.

A positive test "does not equate to infectiousness or viable virus," a joint research paper by Singapore's National Centre for Infectious Diseases and the Academy of Medicine, Singapore said. The virus "could not be isolated or cultured after day 11 of illness."

The paper was based on a study of 73 patents in the city-state.

The latest findings may have implications on the country's patient discharge policy. The discharge criteria is currently based on negative test results rather than infectiousness.

Singapore's strategy on managing COVID-19 patients is guided by the latest local and international clinical scientific evidence, and the Ministry of Health will evaluate if the latest evidence can be incorporated into its patient clinical management plan, according to a report by the Straits Times.

So far, 13,882, or about 45% of the total 31,068 Covid-19 patients in Singapore have been discharged from hospitals and community facilities. Singapore reported 642 new Covid-19 cases as of noon on Saturday.

The government has been actively screening pre-school staff as it prepares to reopen pre-schools from June 2. On Friday, two pre-school employees tested positive for the novel coronavirus, bringing the total number of confirmed cases among pre-school staff to seven, according to the Ministry of Health.

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