From Avian flu to Sepsis: latest CIHR funding round results for LMP

Samira Mubareka, Sunnybrook Research Institute

The primary causes of international outbreaks, public health emergencies of international concern (PHEICs) and pandemics are zoonotic in origin, and the next pandemic pathogen will likely circulate in animals before causing widespread human disease. 

The highly pathogenic avian influenza (HPAI) A(H5Nx) virus is causing a panzootic (a pandemic in animals) through waves of viral activity and unprecedented infections and die offs in wild birds, domestic poultry and both terrestrial and marine mammals. The range of species infected HPAI viruses is unprecedented, with recent transmission involving dairy cows and other animals including cats and mice, as well as humans. 

This unexpected change in viral ecology calls into question the narrow focus of widely used risk assessment tools that focus primarily on human health, and draws attention to the importance of integrating a One Health approach to include other species and novel routes of exposure as novel viruses emerge. To that end, we propose to:

1. expand surveillance for avian influenza viruses in avian species and mammals to understand viral activity in animals, 
2. advance an in-depth characterization of new biological tools to rapidly determine whether HPAI viruses infects and damages cells from different animals as well as humans, and 
3. build a framework for decision making that incorporates risk to both human and animal health based on genomic and biological features to inform surveillance and other key decision-making policies. 

This work builds on the Wildlife Emerging Pathogen (Wild EPI) initiative that brings together researchers from a range of backgrounds and disciplines, leading to the discovery of SARS-CoV-2 in Canadian deer and the first case of deer to human transmission of that virus. HPAI is an important emerging pathogen and a multidisciplinary, One Health approach is needed to address this complex threat to wildlife, domestic animal and human health.

See also: EPIC launches Highly Pathogenic Avian Influenza Rapid Research Response to inform and support comprehensive influenza pandemic preparedness

Isabelle Aubert, Sunnybrook Research Institute

Alzheimer's disease is a devastating condition that causes brain cells to malfunction and die, leading to memory loss and cognitive decline. Current treatments face significant challenges because they cannot effectively protect or replace damaged cells, and therapeutics cannot penetrate the brain's protective barrier. 

We developed a groundbreaking approach using ultrasound and gene transfer technologies to address these issues. This innovative treatment is non-invasive, utilizing a special helmet that generates ultrasound waves, which eliminates the need for brain surgery. The ultrasound waves are precisely targeted to specific affected areas of the brain with the help of MRI guidance, ensuring that the treatment is both safe and effective. 

Our approach employs a dual-action strategy. First, it aims to stimulate the growth of new brain cells. Second, it enhances the delivery of therapeutic genes, allowing them to cross the blood-brain barrier more effectively. A particularly promising aspect of this research involves delivering genes that could respond to the severity of the disease to continuously produce healing compounds within the brain. The progress made so far is exciting and encouraging. The successful completion of the first clinical trial using ultrasound in Alzheimer's patients marks a significant milestone. Ongoing preclinical studies in animal models continue to refine this technique further.

Our goal is to combine ultrasound with gene therapy to achieve long-lasting therapeutic effects. This innovative approach has the potential to significantly improve the quality of life for individuals affected by Alzheimer's disease. By addressing multiple aspects of the disease simultaneously and offering a safer, non-invasive treatment option, this ultrasound-based gene therapy represents a promising direction to develop effective treatments for patients living with Alzheimer's disease.

Jason Fish (with collaborator Dr. Paaladinesh Thavendiranathan), University Health Network.

While breast cancer survival rates have improved, the most commonly used chemotherapy drugs for breast cancer, anthracyclines, can result in serious damage to the heart. Cancer therapy-related cardiac dysfunction (CTRCD) is a serious side effect of cancer treatment that can result in the need to stop cancer treatment, which can allow cancer to progress. In the most serious cases, the damage to the heart cannot be reversed, leading to heart failure. 

Chemotherapy drugs are known to have toxic effects on the cells that line blood vessels (known as endothelial cells) or the beating cells of the heart (cardiomyocytes), but why some patients have devastating damage to these cells is not understood. As a result, it is difficult to predict which patients will develop CTRCD during cancer treatment. Understanding why CTRCD develops will allow us to identify patients who are at risk so that they can receive personalized treatment, be carefully monitored, and to design therapies that protect the blood vessels and heart during cancer treatment. 

We recently discovered that high levels of markers of inflammation and endothelial cell damage can be detected in the blood before cancer treatment is started in breast cancer patients that will go on to develop CTRCD. We will test if the tumour itself is causing systemic inflammation, including inflammation in the heart, which creates a vulnerability to further damage when the patient receives chemotherapy. 

Our objective is to determine if circulating factors in the blood can prime the heart - particularly the small blood vessels of the heart - for damage during cancer treatment. We will use patient blood samples and a mouse model to test this. Furthermore, we will test whether drugs that are being tested for their ability to protect the heart during cancer treatment act by reducing inflammation in the heart and protecting the small blood vessels of the heart.

Maryam Faiz (Department of Surgery)

Stroke is a debilitating disease caused by a blockage of blood flow to the brain. After stroke, astrocytes, a type of non-neuronal cell in the brain, respond and play roles that can be detrimental or beneficial for recovery. Understanding the astrocyte response to stroke and the factors that influence astrocyte functions after injury is important for identifying novel treatment pathways. 

Recent work has shown that gut bacteria may play an important role in determining the function of astrocytes in the brain, however it is unknown how gut bacteria contribute to the types of astrocytes that respond to stroke injury. 

Using a rodent model of stroke injury, the aim of our project is to identify how the gut bacteria modify the types of astrocytes that respond to stroke. This project will be the first to study the relationship between gut bacteria and astrocyte function following stroke. Our hope is that a better understanding of this relationship can be leveraged to improve functional outcomes following injury.

Stephen Juvet (Department of Medicine with collaborator Dr. Tereza Martinu), University Health Network

Lung transplantation is lifesaving for people with terminal lung diseases, but the long-term outcome is poor - only about half of patients survive 6 years due to a scarring process called chronic lung allograft dysfunction (CLAD), which causes severe breathing difficulty. CLAD occurs because the patient's immune system recognizes the lung as foreign and initiates a powerful rejection response against it, which is only partly controlled by anti-rejection drugs. 

We have been exploring pathways leading to CLAD using state-of-the-art techniques and unique samples from our patients. Using single cell RNA sequencing - a technique that looks at active genes in each individual cell - we have a special type of cells called macrophages in the transplanted lung that may be contributing to disease.

In this study, we will examine whether they are associated with lung injury and scarring in an animal model, and we will test their functions in the laboratory. We predict that these macrophages will promote inflammation and kill lung structural cells, and that they will promote scarring by stimulating other cells called fibroblasts to produce scar tissue. We will examine macrophage function and behaviour in cultured slices of human lung tissue. We will use a mouse model that closely mimics human CLAD to study how the mouse counterparts of the human macrophages participate in the rejection process.

Together these experiments will give us a clearer perspective on the contributions of these macrophages to the development of CLAD. For years, there have been no meaningful improvements in survival after lung transplantation. Our goal is to improve the outlook for Canadians with end-stage lung disease undergoing this procedure. Our team of experts, using these novel approaches to CLAD, will yield new insights into this devastating condition.

Warren Lee (Department of Medicine), Unity Health Toronto

Atherosclerosis leads to heart attacks and strokes and is a leading cause of death in Canada. The first step in the disease is the build-up of the bad cholesterol, LDL, in the wall of blood vessels. Specifically, LDL builds up under the innermost layer of arteries, called the endothelium. How the LDL gets under the endothelium is very poorly understood. 

We have discovered ways to study this process, which is known as LDL transcytosis. In earlier work, we discovered two molecules on the cell surface that bring LDL into the endothelial cell but almost nothing is known about what happens next. We now wish to understand the route taken by LDL as it traverses the cell. Does it interact with other parts of the cell? How does it move through the crowded cell? 

Understanding how LDL navigates across the endothelial cell will help us develop ways to prevent the development of heart disease. If we can prevent cholesterol from accumulating in the blood vessel wall, we will prevent heart disease and stroke.

We will use sophisticated microscopes to study the process by which cholesterol builds up under the special cells that line blood vessels, known as endothelium. We will identify the specific molecules that regulate this build-up. We will also prove that our findings from cells hold true in mice, which are the typical animals used in studies of atherosclerosis. We will compare our findings using cells from men as well as women to determine if there is a sex-based difference. 

We are the only lab in Canada to study this process of transcytosis, by which the bad cholesterol (LDL) gets under endothelial cells. We therefore have the potential to make huge advances in this field of research.

Claudia Dos Santos (Department of Medicine with collaborator Dr. Teodor Veres), Unity Health Toronto

Sepsis, is a life-threatening inappropriate response to infection that may lead to organ failure and death. Early treatment may reduce human suffering and staggering costs. The problem is there are no biomarkers in clinical use that may predict early, which patients are at risk for serious deterioration. 

In collaboration with the National Research Council of Canada, we developed a diagnostics point-of-care device called PREDICT-PowerBlade (PREDICT-PB). The PowerBlade uses microfluidic technology. The team used machine learning and AI to identify and test a new gene-based signature of sepsis deterioration and adapted it for detection on the PowerBlade. In patients with suspected sepsis, the PREDICT-PB is capable of predicting clinical deterioration 24-48 hrs after presentation with an overall accuracy of 93%. We benchmarked results using 'gold standard' techniques and performed analytical validation of the PREDICT-PB device using patient samples. PREDICT-PB performs gene extraction from 50 microliters of whole blood and links it to gene detection making results available within 3 hours, compared to 1-3 days by a conventional lab. 

Here we propose the first prospective study to test the PREDICT-PB in the 'real-world' patient environment. We will recruit 100 patients from the emergency and the intensive care unit with suspected sepsis and 50 controls, to evaluate, compare and combine results from the PREDICT-PB with clinical and laboratory measures commonly used. We defined deteriorations as any of the following: ICU admission, initiation of respiratory support (non-invasive ventilatory support), endotracheal intubation, administration of vasopressors/inotropes, or death within the first 24 to 72 hours of presentation. We will study the ability of PREDICT-PB to make accurate predictions, determine if by adding other clinical data we can improve these predictions and the feasibility of using the device at the bedside. Success may fast-track deployment to the clinic.

Adele Changoor (Department of Surgery) and Marc Grynpas, Sinai Health System

Younger, active individuals experiencing pain and loss of mobility due to large areas of damaged cartilage in their joints can be treated with a surgery known as fresh osteochondral allograft transplantation (OCAT). OCAT replaces degraded cartilage with pieces of mature bone and cartilage obtained from a donor and the majority of patients experience improved quality of life after surgery. 

While Canadian tissue banks can keep donor tissues viable for up to 14 days, there is a need for better methods to increase storage times and make more donor tissues available for transplantation. We created a new storage medium that simulates features of the native joint environment. Results in rabbits showed that cartilage can be kept alive for up to two months. 
These positive findings encourage further study and our research aims to investigate the ability of the novel medium to preserve human tissues and understand whether tissues stored using the novel medium are durable after transplantation. Validation studies will measure human cell viability and cartilage structure. Long-term performance of grafts stored using the novel medium will be evaluated using sheep because this animal model shares similarities with humans and graft quality and integration can be studied over time using magnetic resonance imaging. Our team is experienced with OCAT, including performing research that measures cartilage health, carrying out animal studies, performing OCAT in human patients, and collaborating with a Canadian tissue bank. 
If successful, our novel storage medium would quadruple the time when human osteochondral tissues in Canada are healthy enough for transplantation. This would be a crucial advancement, especially for younger patients who are not eligible for joint replacement surgery. This research will also lay the groundwork for meeting the requirements to have the novel storage medium approved for use by Canadian tissue banks for transplantation into patients.