Publications by authors named "Zaniar Ghazizadeh"

Aims: Deep learning methods have shown impressive performance in detecting a range of diseases from electrocardiogram (ECG) waveforms, but the breadth of diseases that can be detected with high accuracy remains unknown, and in many cases the changes to the ECG allowing these classifications are also opaque. In this study, we aim to determine the full set of cardiac and non-cardiac conditions detectable from the ECG and to understand which ECG features contribute to the disease classification.

Methods And Results: Using large datasets of ECGs and connected electronic health records from two separate medical centres, we independently trained PheWASNet, a multi-task deep learning model, to detect 1243 different disease phenotypes from the raw ECG waveform.

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Gastrointestinal (GI) motility disorders represent a major medical challenge, with few effective therapies available. These disorders often result from dysfunction of inhibitory nitric oxide (NO)-producing motor neurons in the enteric nervous system, which are essential for regulating gut motility. Loss or dysfunction of NO neurons is linked to severe conditions, including achalasia, gastroparesis, intestinal pseudo-obstruction and chronic constipation.

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Disorders of gut-brain interaction (DGBIs), formerly known as functional gastrointestinal disorders, are extremely common and historically difficult to manage. This is largely because their cellular and molecular mechanisms have remained poorly understood and understudied. One approach to unravel the molecular underpinnings of complex disorders such as DGBIs is performing genome wide association studies (GWASs).

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Schwann cells (SCs) are the primary glia of the peripheral nervous system. SCs are involved in many debilitating disorders, including diabetic peripheral neuropathy (DPN). Here, we present a strategy for deriving SCs from human pluripotent stem cells (hPSCs) that enables comprehensive studies of SC development, physiology, and disease.

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Article Synopsis
  • Tyrosine kinase inhibitors (TKIs) are commonly used for treating various cancers, but they may lead to serious cardiovascular issues, particularly ventricular arrhythmias (VAs), which are not well-studied compared to other heart conditions.
  • A review of five patient cases from 2019 to 2022 found that VAs occurred in individuals with different heart health backgrounds, and these issues improved after stopping TKI therapy, although some needed additional heart medications or devices.
  • The study emphasizes the importance of recognizing the risk of VAs from TKIs in cancer patients and suggests the need for better monitoring and treatment methods to manage these potential cardiovascular side effects.
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The sinoatrial node (SAN) is the primary pacemaker of the heart. The human SAN is poorly understood due to limited primary tissue access and limitations in robust derivation methods. We developed a dual knockin human embryonic stem cell (hESC) reporter line, which allows the identification and purification of SAN-like cells.

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Individuals with established cardiovascular disease or a high burden of cardiovascular risk factors may be particularly vulnerable to develop complications from coronavirus disease 2019 (COVID-19). We conducted a prospective cohort study at a tertiary care center to identify risk factors for in-hospital mortality and major adverse cardiovascular events (MACE; a composite of myocardial infarction, stroke, new acute decompensated heart failure, venous thromboembolism, ventricular or atrial arrhythmia, pericardial effusion, or aborted cardiac arrest) among consecutively hospitalized adults with COVID-19, using multivariable binary logistic regression analysis. The study population comprised 586 COVID-19 positive patients.

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SARS-CoV-2 infection has led to a global health crisis, and yet our understanding of the disease and potential treatment options remains limited. The infection occurs through binding of the virus with angiotensin converting enzyme 2 (ACE2) on the cell membrane. Here, we established a screening strategy to identify drugs that reduce ACE2 levels in human embryonic stem cell (hESC)-derived cardiac cells and lung organoids.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has led to a global health crisis, and yet our understanding of the disease pathophysiology and potential treatment options remains limited. SARS-CoV-2 infection occurs through binding and internalization of the viral spike protein to angiotensin converting enzyme 2 (ACE2) on the host cell membrane. Lethal complications are caused by damage and failure of vital organs that express high levels of ACE2, including the lungs, the heart and the kidneys.

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Background: Atrial fibrillation (AF) is the most common clinical arrhythmia and is associated with heart failure, stroke, and increased mortality. The myocardial substrate for AF is poorly understood because of limited access to primary human tissue and mechanistic questions around existing in vitro or in vivo models.

Methods: Using an knock-in reporter line, we developed a protocol to generate and highly purify human pluripotent stem cell-derived cardiomyocytes displaying physiological and molecular characteristics of atrial cells.

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Aims: Human embryonic stem cells (hESCs) can be used to generate scalable numbers of cardiomyocytes (CMs) for studying cardiac biology, disease modelling, drug screens, and potentially for regenerative therapies. A fluorescence-based reporter line will significantly enhance our capacities to visualize the derivation, survival, and function of hESC-derived CMs. Our goal was to develop a reporter cell line for real-time monitoring of live hESC-derived CMs.

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One of the major issues in cell therapy of myocardial infarction (MI) is early death of engrafted cells in a harsh oxidative stress environment, which limits the potential therapeutic utility of this strategy in the clinical setting. Increasing evidence implicates beneficial effects of omega-3 fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and ascorbic acid (AA) in cardiovascular diseases, in particular their role in ameliorating fibrosis. In the current study, we aim to assess the cytoprotective role of EPA + DHA and AA in protecting embryonic stem cell (ESC)-derived cardiac lineage cells and amelioration of fibrosis.

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Common disorders, including diabetes and Parkinson's disease, are caused by a combination of environmental factors and genetic susceptibility. However, defining the mechanisms underlying gene-environment interactions has been challenging due to the lack of a suitable experimental platform. Using pancreatic β-like cells derived from human pluripotent stem cells (hPSCs), we discovered that a commonly used pesticide, propargite, induces pancreatic β-cell death, a pathological hallmark of diabetes.

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GLIS3 mutations are associated with type 1, type 2, and neonatal diabetes, reflecting a key function for this gene in pancreatic β-cell biology. Previous attempts to recapitulate disease-relevant phenotypes in GLIS3 β-like cells have been unsuccessful. Here, we develop a "minimal component" protocol to generate late-stage pancreatic progenitors (PP2) that differentiate to mono-hormonal glucose-responding β-like (PP2-β) cells.

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The LIM-homeodomain transcription factor ISL1 marks multipotent cardiac progenitors that give rise to cardiac muscle, endothelium, and smooth muscle cells. ISL1 progenitors can be derived from human pluripotent stem cells, but the inability to efficiently isolate pure populations has limited their characterization. Using a genetic selection strategy, we were able to highly enrich ISL1 cells derived from human embryonic stem cells.

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Diabetes is linked to loss of pancreatic beta-cells. Pluripotent stem cells offer a valuable source of human beta-cells for basic studies of their biology and translational applications. However, the signalling pathways that regulate beta-cell development and functional maturation are not fully understood.

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Derivation of cardiomyocytes directly from patients' own fibroblasts could offer a new therapeutic approach for those with ischemic heart disease. An essential step toward clinical application is to establish safe conversion of human fibroblasts into a cardiac fate. Here we aimed to efficiently and safely generate cardiomyocytes from human fibroblasts by direct delivery of reprogramming recombinant cell permeant form of reprogramming proteins followed by cardio-inductive signals.

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Aims: Magnesium is a cofactor for numerous metabolic enzymatic reactions. It is required for glucose utilization and insulin signaling. We compared plasma magnesium concentrations in pregnant women with and without abdominal obesity, and investigated the interactive roles of magnesium and obesity in the development of gestational diabetes mellitus (GDM).

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Aims: Regenerative therapies based on resident human cardiac progenitor cells (hCPCs) are a promising alternative to medical treatments for patients with myocardial infarction. However, hCPCs are rare in human heart and finding efficient source and proper surface marker for isolation of these cells would make them a good candidate for therapy.

Main Methods: We have isolated 5.

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Embryonic stem cells offer multiple advantages over adult stem cells in terms of achieving acceptable number of functional cardiomyocytes to be exploited in cell therapy. However, differentiation efficacy is still a major issue to be solved before moving to regenerative medicine. Although a vast number of chemical compounds have been tested on efficiency of cardiac differentiation, the effect of fish oil components, such as eicosapentaenoic acid (EPA) on developmental bioenergetics, and hence cardiac differentiation, remained unstudied.

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Cell therapy of heart diseases is emerging as one of the most promising known treatments in recent years. Transplantation of cardiac stem cells (CSCs) may be one of the best strategies to cure adult or pediatric heart diseases. As these patient-derived stem cells need to be isolated from small heart biopsies, it is important to select the best isolation method and CSC subpopulation with the best cardiogenic functionality.

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Article Synopsis
  • Heat shock proteins, specifically HSPA1A, have been linked to rheumatoid arthritis (RA), and this study explores their potential as a diagnostic tool and severity indicator.
  • The research involved 76 RA patients and 36 healthy adults, revealing significantly higher HSPA1A levels in RA patients, which accurately predicted RA status at levels over 0.42 ng/mL with over 90% specificity.
  • HSPA1A levels also differentiated between high disease activity and other phases of RA (low, moderate, or remission), suggesting its usefulness for both diagnosis and monitoring disease progression.
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