Like the arms of spectators rising and falling in unison during a ‘stadium wave’ at a game, the muscles in the heart contract in unison across the heart. This concerted contraction efficiently pumps blood throughout the body.
However, after a heart attack, regions of the heart can become damaged and lose their ability to contract. “When a heart attack occurs, muscle cells known as cardiomyocytes die in the affected regions,” says Dr. Ren-Ke Li, a Senior Scientist at the Toronto General Hospital Research Institute.
The damaged cardiomyocytes break the wave of contraction, resulting in potentially life-threatening conditions, such as arrhythmias (ie, irregular heartbeat) and heart disease.
To address this issue, Dr. Li developed a new biomaterial in the form of a gel that can be injected into damaged heart tissue to reconnect healthy tissue and restore efficient heart contraction.
The biomaterial that Dr. Li’s team created is known as poly-3-amino-4-methoxybenzoic acid (PAMB). It is unique in that it is a conductive polymer, which means it can relay electric signals. In order to improve the biocompatibility of PAMB, the researchers combined it with another gel-like material known as gelatin, which is less likely to harm living tissue.
In a study published in Biomaterials, Dr. Li’s team studied the effect of the biomaterial in an experimental model that mimics a human heart attack. They discovered that injecting the novel conductive biomaterial into damaged regions of the heart one week after heart injury greatly improved the coordinated heart contraction, improved heart function and reduced arrhythmia.
“While these findings are preliminary, they show that by customizing and combining biomaterials, we can create new injectable conductive gels that support the restoration of electrical function in the damaged heart. Further development of this approach could lead to new therapies for those suffering from cardiovascular diseases, which are a leading cause of death worldwide,” says Dr. Li.
Dr. Ren-Ke Li is a Tier 1 Canada Research Chair in Cardiac Regeneration. This work was supported by the Canadian Institutes of Health Research; the Ministry of Science and Technology of the People's Republic of China (ROC); the Ministry of Education of Taiwan, ROC; and the Toronto General & Western Hospital Foundation.
Zhang C, Hsieh MH, Wu SY, Li SH, Wu J, Liu SM, Wei HJ, Weisel RD, Sung HW, Li RK. A self-doping conductive polymer hydrogel that can restore electrical impulse propagation at myocardial infarct to prevent cardiac arrhythmia and preserve ventricular function. Biomaterials. 2020;231:119672. doi:10.1016/j.biomaterials.2019.119672.
Magnetic resonance imaging (MRI) is a powerful tool that doctors use to visualize organs and tissues in three dimensions. While the images can provide key insights, the high cost and low availability of MRI systems has led to long wait times for patients.
Dr. Masoom Haider, an Affiliate Scientist with the Techna Institute and a Clinician Scientist in the Joint Department of Medical Imaging, has devised a method for reducing MRI demand by avoiding unnecessary scans for patients at risk of prostate cancer. He says that the new strategies, “may support clinical decisions for a more judicious application of MRI to further improve the cost-benefit ratio.”
Dr. Haider, along with his research fellow Dr. Dominik Deniffel and research team, sought to find alternatives to MRI scans among other more readily available and inexpensive clinical parameters. They wondered whether factors such as age, prostate size or the presence of molecular markers could predict MRI results.
The team began by collecting data from hundreds of patients who were at risk of prostate cancer and who had undergone MRI screening. The researchers then built a statistical model for finding patterns and making predictions—to categorize patient risk. The model was then used to predict whether an MRI scan would reveal prostate cancer.
The researchers found that if doctors were to implement this model, 29% fewer patients would need MRI scans. Skipping MRI for these patients would rarely lead to missed prostate cancer diagnosis.
As part of the model building, the researchers discovered that one patient factor was particularly informative in predicting risk: the density of a molecular marker known as prostate specific antigen (PSA). Dr. Haider’s team found that by applying a patient cut-off for this factor alone, the number of patients perceived as needing MRI scans could be reduced by 25%.
Although the predictive power of PSA density is slightly weaker than that of the full model, a cut-off for PSA density could be easily implemented as a low-cost and routine filter for MRI testing.
This work was supported by the Ontario Institute for Cancer Research, a Deutsche Forschungsgemeinschaft (DFG) Fellowship and Sinai Health Foundation.
Deniffel D, Zhang Y, Salinas E, Satkunasivam R, Khalvati F, Haider MA. Reducing Unnecessary Prostate Multiparametric Magnetic Resonance Imaging by Using Clinical Parameters to Predict Negative and Indeterminate Findings. J Urol. 2020 Feb. doi: 10.1097/JU.0000000000000518.
Hospital intensive care units attend to patients with life-threatening or critical conditions. After a stay in the intensive care unit, patients who are released from the hospital are often severely weakened and may experience long-term disabilities.
“Identifying patients who will have serious difficulties recovering from illness is a challenge,” says Dr. Ewan Goligher, a Scientist with the Toronto General Hospital Research Institute.
Prompted by this challenge, Dr. Goligher and his team initiated a study that focused on patients being aided by a breathing machine—a procedure also known as invasive ventilation. In this procedure, a breathing tube is inserted into the throat so that air can be mechanically pumped into and out of the lungs to help the patient breathe.
In their study, the researchers examined patients who had received invasive ventilation at hospitals in Toronto and tracked their recovery. The researchers measured the thickness of patients’ diaphragms—the primary muscle used for breathing—using ultrasound imaging.
The study results revealed that the patients with more muscle mass in their diaphragms when first admitted had a lower risk of death in hospital. As well, they were less likely to develop complications and recovered from respiratory assistance significantly faster.
While the results may help identify the patients who are at risk for poor recovery, they could also enable the development of new, proactive approaches to reducing these risks. In cases where doctors can foresee a patient needing ventilation, such as following organ transplant or for serious illnesses like cancer, exercises aimed at strengthening the diaphragm could be prescribed.
This work was supported by the Canadian Institutes of Health Research and Toronto General & Western Hospital Foundation.
Sklar MC, Dres M, Fan E, Rubenfeld GD, Scales DC, Herridge MS, Rittayamai N, Harhay MO, Reid WD, Tomlinson G, Rozenberg D, McClelland W, Riegler S, Slutsky AS, Brochard L, Ferguson ND, Goligher EC. Association of Low Baseline Diaphragm Muscle Mass with Prolonged Mechanical Ventilation and Mortality Among Critically Ill Adults. JAMA Network Open. 2020 Feb 19. doi:10.1001/jamanetworkopen.2019.21520.
The CenteR for Advancing Neurotechnological Innovation to Application (CRANIA) is hosting its inaugural workshop as part of an Industry Partnership Day Workshop Series.
The half-day workshop is on February 21, 2020; and registration is open to all staff and researchers involved in neuromodulation research (maximum 70 registrants, first-come-first-served). The workshop will highlight state-of-the-art neural implants—with a focus on Novela Neurotech’s new Open Source Wireless Neuromodulation Research Kit (OpenKit).
The workshop is also a call for collaboration to further develop OpenKit. All research teams that employ electrophysiological techniques/protocols or are interested in learning about the future of neuromodulation therapies are invited to participate.
Ten event registrants will be selected to receive a complimentary OpenKit system, which features a state-of-the-art wireless and flexible neural implant, bluetooth communication module and a software suite with smartphone integration. The kit is open-sourced to promote collaboration and greatly advances multi-channel recording, data processing and sharing capabilities.
Event details are listed below:
● Date and Time: Friday, February 21, 2020 from 12:30 to 4:30 pm
● Venue: Room GB303, Galbraith Building, 35 St. George Street, University of Toronto [map]
Research conducted at UHN's research institutes spans the full spectrum of diseases and disciplines, including cancer, cardiovascular sciences, transplantation, neural and sensory sciences, musculoskeletal health, rehabilitation sciences, and community and population health.
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