1
|
Kostina A, Lewis-Israeli YR, Abdelhamid M, Gabalski MA, Kiselev A, Volmert BD, Lankerd H, Huang AR, Wasserman AH, Lydic T, Chan C, Park S, Olomu I, Aguirre A. ER stress and lipid imbalance drive diabetic embryonic cardiomyopathy in an organoid model of human heart development. Stem Cell Reports 2024; 19:317-330. [PMID: 38335962 PMCID: PMC10937107 DOI: 10.1016/j.stemcr.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/12/2024] Open
Abstract
Congenital heart defects are the most prevalent human birth defects, and their incidence is exacerbated by maternal health conditions, such as diabetes during the first trimester (pregestational diabetes). Our understanding of the pathology of these disorders is hindered by a lack of human models and the inaccessibility of embryonic tissue. Using an advanced human heart organoid system, we simulated embryonic heart development under pregestational diabetes-like conditions. These organoids developed pathophysiological features observed in mouse and human studies before, including ROS-mediated stress and cardiomyocyte hypertrophy. scRNA-seq revealed cardiac cell-type-specific dysfunction affecting epicardial and cardiomyocyte populations and alterations in the endoplasmic reticulum and very-long-chain fatty acid lipid metabolism. Imaging and lipidomics confirmed these findings and showed that dyslipidemia was linked to fatty acid desaturase 2 mRNA decay dependent on IRE1-RIDD signaling. Targeting IRE1 or restoring lipid levels partially reversed the effects of pregestational diabetes, offering potential preventive and therapeutic strategies in humans.
Collapse
Affiliation(s)
- Aleksandra Kostina
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Yonatan R Lewis-Israeli
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Mishref Abdelhamid
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Division of Neonatology, Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, East Lansing, MI, USA
| | - Mitchell A Gabalski
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Artem Kiselev
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Pharmacology and Toxicology, College of Human Medicine, Michigan State University, MI, USA; Division of Dermatology, Department of Medicine, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Brett D Volmert
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Haley Lankerd
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Amanda R Huang
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Aaron H Wasserman
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Todd Lydic
- Department of Physiology, Michigan State University, MI, USA
| | - Christina Chan
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA; Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI, USA; Division of Biomedical Devices, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
| | - Sangbum Park
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Pharmacology and Toxicology, College of Human Medicine, Michigan State University, MI, USA; Division of Dermatology, Department of Medicine, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Isoken Olomu
- Division of Neonatology, Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, East Lansing, MI, USA
| | - Aitor Aguirre
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA; Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA.
| |
Collapse
|
2
|
Kostina A, Lewis-Israeli YR, Abdelhamid M, Gabalski MA, Volmert BD, Lankerd H, Huang AR, Wasserman AH, Lydic T, Chan C, Olomu I, Aguirre A. ER stress and lipid imbalance drive embryonic cardiomyopathy in a human heart organoid model of pregestational diabetes. bioRxiv 2023:2023.06.07.544081. [PMID: 37333095 PMCID: PMC10274758 DOI: 10.1101/2023.06.07.544081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Congenital heart defects constitute the most common birth defect in humans, affecting approximately 1% of all live births. The incidence of congenital heart defects is exacerbated by maternal conditions, such as diabetes during the first trimester. Our ability to mechanistically understand these disorders is severely limited by the lack of human models and the inaccessibility to human tissue at relevant stages. Here, we used an advanced human heart organoid model that recapitulates complex aspects of heart development during the first trimester to model the effects of pregestational diabetes in the human embryonic heart. We observed that heart organoids in diabetic conditions develop pathophysiological hallmarks like those previously reported in mouse and human studies, including ROS-mediated stress and cardiomyocyte hypertrophy, among others. Single cell RNA-seq revealed cardiac cell type specific-dysfunction affecting epicardial and cardiomyocyte populations, and suggested alterations in endoplasmic reticulum function and very long chain fatty acid lipid metabolism. Confocal imaging and LC-MS lipidomics confirmed our observations and showed that dyslipidemia was mediated by fatty acid desaturase 2 (FADS2) mRNA decay dependent on IRE1-RIDD signaling. We also found that the effects of pregestational diabetes could be reversed to a significant extent using drug interventions targeting either IRE1 or restoring healthy lipid levels within organoids, opening the door to new preventative and therapeutic strategies in humans.
Collapse
Affiliation(s)
- Aleksandra Kostina
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Yonatan R. Lewis-Israeli
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Mishref Abdelhamid
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Division of Neonatology, Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, East Lansing, MI, USA
| | - Mitchell A. Gabalski
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Brett D. Volmert
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Haley Lankerd
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Amanda R. Huang
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Aaron H. Wasserman
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| | - Todd Lydic
- Department of Physiology, Michigan State University, MI, USA
| | - Christina Chan
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
- Department of Chemical Engineering and Materials Science, Michigan State University, MI, USA
| | - Isoken Olomu
- Division of Neonatology, Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, East Lansing, MI, USA
| | - Aitor Aguirre
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
3
|
Wasserman AH, Huang AR, Lewis-Israeli YR, Dooley MD, Mitchell AL, Venkatesan M, Aguirre A. Oxytocin promotes epicardial cell activation and heart regeneration after cardiac injury. Front Cell Dev Biol 2022; 10:985298. [PMID: 36247002 PMCID: PMC9561106 DOI: 10.3389/fcell.2022.985298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
Cardiovascular disease (CVD) is one of the leading causes of mortality worldwide, and frequently leads to massive heart injury and the loss of billions of cardiac muscle cells and associated vasculature. Critical work in the last 2 decades demonstrated that these lost cells can be partially regenerated by the epicardium, the outermost mesothelial layer of the heart, in a process that highly recapitulates its role in heart development. Upon cardiac injury, mature epicardial cells activate and undergo an epithelial-mesenchymal transition (EMT) to form epicardium-derived progenitor cells (EpiPCs), multipotent progenitors that can differentiate into several important cardiac lineages, including cardiomyocytes and vascular cells. In mammals, this process alone is insufficient for significant regeneration, but it might be possible to prime it by administering specific reprogramming factors, leading to enhanced EpiPC function. Here, we show that oxytocin (OXT), a hypothalamic neuroendocrine peptide, induces epicardial cell proliferation, EMT, and transcriptional activity in a model of human induced pluripotent stem cell (hiPSC)-derived epicardial cells. In addition, we demonstrate that OXT is produced after cardiac cryoinjury in zebrafish, and that it elicits significant epicardial activation promoting heart regeneration. Oxytocin signaling is also critical for proper epicardium development in zebrafish embryos. The above processes are significantly impaired when OXT signaling is inhibited chemically or genetically through RNA interference. RNA sequencing data suggests that the transforming growth factor beta (TGF-β) pathway is the primary mediator of OXT-induced epicardial activation. Our research reveals for the first time an evolutionary conserved brain-controlled mechanism inducing cellular reprogramming and regeneration of the injured mammalian and zebrafish heart, a finding that could contribute to translational advances for the treatment of cardiac injuries.
Collapse
Affiliation(s)
- Aaron H Wasserman
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, United States
| | - Amanda R Huang
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, United States
| | - Yonatan R Lewis-Israeli
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, United States
| | - McKenna D Dooley
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, United States
| | - Allison L Mitchell
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, United States
| | - Manigandan Venkatesan
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, United States
| | - Aitor Aguirre
- Division of Developmental and Stem Cell Biology, Institute for Quantitative Health Science and Engineering (IQ), Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, College of Engineering, Michigan State University, East Lansing, MI, United States
| |
Collapse
|
4
|
Lewis-Israeli YR, Volmert BD, Gabalski MA, Huang AR, Aguirre A. Generating Self-Assembling Human Heart Organoids Derived from Pluripotent Stem Cells. J Vis Exp 2021. [PMID: 34605811 DOI: 10.3791/63097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The ability to study human cardiac development in health and disease is highly limited by the capacity to model the complexity of the human heart in vitro. Developing more efficient organ-like platforms that can model complex in vivo phenotypes, such as organoids and organs-on-a-chip, will enhance the ability to study human heart development and disease. This paper describes a protocol to generate highly complex human heart organoids (hHOs) by self-organization using human pluripotent stem cells and stepwise developmental pathway activation using small molecule inhibitors. Embryoid bodies (EBs) are generated in a 96-well plate with round-bottom, ultra-low attachment wells, facilitating suspension culture of individualized constructs. The EBs undergo differentiation into hHOs by a three-step Wnt signaling modulation strategy, which involves an initial Wnt pathway activation to induce cardiac mesoderm fate, a second step of Wnt inhibition to create definitive cardiac lineages, and a third Wnt activation step to induce proepicardial organ tissues. These steps, carried out in a 96-well format, are highly efficient, reproducible, and produce large amounts of organoids per run. Analysis by immunofluorescence imaging from day 3 to day 11 of differentiation reveals first and second heart field specifications and highly complex tissues inside hHOs at day 15, including myocardial tissue with regions of atrial and ventricular cardiomyocytes, as well as internal chambers lined with endocardial tissue. The organoids also exhibit an intricate vascular network throughout the structure and an external lining of epicardial tissue. From a functional standpoint, hHOs beat robustly and present normal calcium activity as determined by Fluo-4 live imaging. Overall, this protocol constitutes a solid platform for in vitro studies in human organ-like cardiac tissues.
Collapse
Affiliation(s)
- Yonatan R Lewis-Israeli
- Institute for Quantitative Health Science and Engineering, Division of Developmental and Stem Cell Biology, Michigan State University; Department of Biomedical Engineering, College of Engineering, Michigan State University
| | - Brett D Volmert
- Institute for Quantitative Health Science and Engineering, Division of Developmental and Stem Cell Biology, Michigan State University; Department of Biomedical Engineering, College of Engineering, Michigan State University
| | - Mitchell A Gabalski
- Institute for Quantitative Health Science and Engineering, Division of Developmental and Stem Cell Biology, Michigan State University; Department of Biomedical Engineering, College of Engineering, Michigan State University
| | - Amanda R Huang
- Institute for Quantitative Health Science and Engineering, Division of Developmental and Stem Cell Biology, Michigan State University; Department of Biomedical Engineering, College of Engineering, Michigan State University
| | - Aitor Aguirre
- Institute for Quantitative Health Science and Engineering, Division of Developmental and Stem Cell Biology, Michigan State University; Department of Biomedical Engineering, College of Engineering, Michigan State University;
| |
Collapse
|
5
|
Wasserman AH, Huang AR, Aguirre A. Abstract 509: Oxytocin Mediates Neuroendocrine Reprogramming of the Epicardium in Heart Regeneration. Circ Res 2020. [DOI: 10.1161/res.127.suppl_1.509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiovascular disease (CVD) is the leading cause of mortality both in the United States and worldwide. CVD often results in the massive loss of contractile cardiac cells and tissue. Critical work in the last two decades demonstrates that lost cells can be partially replenished by the epicardium, the outermost mesothelial layer of the heart. Upon cardiac injury, mature epicardial cells activate and undergo epithelial-mesenchymal transition (EMT) to form epicardium-derived progenitor cells (EPDCs), which are a type of multipotent stem cell that can differentiate into several important cardiac lineages, including cardiomyocytes and vascular cells. This process alone is insufficient for significant regeneration, but its efficiency can be improved by priming with specific factors (e.g., thymosin beta-4). Our group has recently discovered evidence that oxytocin (OT), a hypothalamic neuroendocrine peptide, induces a pro-regenerative phenotype
in vitro
in human induced pluripotent stem cell (iPSC) derived epicardial cells. We hypothesize that upon cardiac injury, oxytocin is released into the bloodstream, causing activation of the epicardium and mobilization of EPDCs to elicit regeneration of damaged tissue and restoration of function. Here, we show that we can differentiate mature, high-quality epicardial cells from iPSCs and that Ki67 levels and cell counts increase after three days of OT exposure. In addition, the peptide alters gene expression levels of several epithelial, mesenchymal, and EMT markers, indicating a transition to a dedifferentiated gene profile characteristic of EPDCs. Finally, when OT is administered intravenously to mice, it accelerates healing from cardiac injury by inducing epicardial activation. Future studies will aim to further reveal the physiological contribution of OT to heart regeneration
in vivo
and determine its molecular mechanism of action. Our findings have the potential to uncover a novel mechanism of neuroendocrine reprogramming of the injured heart and yield significant translational advances in the treatment of CVD.
Collapse
|
6
|
Lapham SJ, Huang AR, Strombotne KL, Lyter Achorn D, Mokyr Horner E. OVERVIEW OF THE PROJECT TALENT-MEDICARE LINKED DATA (PT-MED). Innov Aging 2018. [DOI: 10.1093/geroni/igy023.2047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- S J Lapham
- American Institutes for Research, Washington, District of Columbia, United States
| | - A R Huang
- American Institutes for Research, Washington, DC, USA
| | | | | | | |
Collapse
|
7
|
Nazerali N, Freter S, Windholz S, Morais J, Bacher Y, Jones S, Kuyumjian J, Huang AR. Caring for an aging population. CMAJ 1998; 159:647-8; author reply 649-50. [PMID: 9780960 PMCID: PMC1229687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
|
8
|
McLeod PJ, Huang AR, Tamblyn RM, Gayton DC. Defining inappropriate practices in prescribing for elderly people: a national consensus panel. CMAJ 1997; 156:385-91. [PMID: 9033421 PMCID: PMC1226961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVE To develop a consensus-based list of inappropriate practices in prescribing for elderly people. DESIGN Mail survey of a 32-member national panel. SETTING Academic medical centres across Canada. PARTICIPANTS Thirty-two specialists selected arbitrarily, including 7 clinical pharmacologists, 9 geriatricians, 8 family practitioners and 8 pharmacists. OUTCOME MEASURES Consensus that the practice would introduce a substantial and significant increase in the risk of serious adverse effect and is common enough that its curtailment would decrease morbidity among elderly people, ranking of clinical importance of the risk, and availability of equally or more effective and less risky alternative therapy. RESULTS The 32-member national panel developed a list of 71 practices in prescribing for elderly people and rated the clinical significance of each on a scale of 1 (not significant) to 4 (highly significant). The practices in prescribing identified fell into 3 categories: drugs generally contraindicated for elderly people, drug-disease interactions and drug-drug interactions. The mean significance rating was greater than 3 for 39 practices. For each practice, alternative therapies were recommended. There was surprising congruence among the specialists on the significance rating and the suggested alternative therapies. CONCLUSION The authors have developed a valid, relevant list of inappropriate practices in prescribing for elderly people, to be used in a practice-based intervention study.
Collapse
Affiliation(s)
- P J McLeod
- Department of Medicine, McGill University, Montreal, Que
| | | | | | | |
Collapse
|
9
|
Tamblyn RM, McLeod PJ, Abrahamowicz M, Monette J, Gayton DC, Berkson L, Dauphinee WD, Grad RM, Huang AR, Isaac LM. Questionable prescribing for elderly patients in Quebec. CMAJ 1994; 150:1801-9. [PMID: 8199957 PMCID: PMC1337055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVE To estimate the prevalence of questionable and rational high-risk prescribing among elderly people of the three drug groups most commonly implicated in drug-related illness: cardiovascular drugs, psychotropic drugs and nonsteroidal anti-inflammatory drugs (NSAIDs). DESIGN Retrospective prevalence study; all prescription and billing records for the period Jan. 1 to Dec. 31, 1990, for the study sample were retrieved from the relevant provincial databases of the Régie de l'assurance-maladie du Québec. SETTING Quebec. PARTICIPANTS Regionally stratified random sample of 63,268 elderly medicare registrants who made at least one visit to physician in 1990 and were not living in a health care institution for the entire year. MAIN OUTCOME MEASURE Prescription information was examined for three types of high-risk prescribing: rational and questionable drug combinations, excessive treatment duration and drugs relatively contraindicated for use in elderly people. RESULTS Overall, 52.6% of the patients experienced one or more events of high-risk prescribing, and 45.6% experienced at least one that was questionable. High-risk prescribing was most prevalent for psychotropic drugs, and questionable prescribing was more frequent than rational prescribing in this drug group. An estimated 30.8% of the total elderly population in Quebec received benzodiazepines for more than 30 consecutive days, 12.9% received a long-acting benzodiazepine, and 13.0% received a questionable high-risk psychotropic drug combination. The prevalence of high-risk prescribing was higher among the women than among the men and increased with age until 75 to 84 years. There were significant unexplained differences between regions in the regional prevalence of high-risk prescribing, particularly of psychotropic drugs. CONCLUSION The prevalence of questionable high-risk prescribing, especially of psychotropic drugs, is substantial among elderly people. This may be a potentially important and avoidable risk factor for drug-related illness in elderly people.
Collapse
Affiliation(s)
- R M Tamblyn
- Department of Medicine, McGill University, Montreal, Que
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Huang AR. Nasogastric tube placement. CMAJ 1992; 147:1756. [PMID: 1458412 PMCID: PMC1336629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
|
11
|
Affiliation(s)
- A R Huang
- Division of Geriatrics, Royal Victoria Hospital, Montreal, Quebec, Canada
| | | |
Collapse
|
12
|
Huang AR, Ponka P. A study of the mechanism of action of pyridoxal isonicotinoyl hydrazone at the cellular level using reticulocytes loaded with non-heme 59Fe. Biochim Biophys Acta 1983; 757:306-15. [PMID: 6849979 DOI: 10.1016/0304-4165(83)90056-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Pyridoxal isonicotinoyl hydrazone (PIH) has recently been identified as a new iron chelating agent with a high degree of iron mobilizing activity in vitro and in vivo which makes this compound a candidate drug in the treatment of iron overload. This study was undertaken to elucidate the mechanism of action of the iron mobilizing activity of PIH at the cellular level. An in vitro system of rabbit reticulocytes with a high level of non-heme 59Fe was used as a model of iron overload. The effects of various biochemical and physiological maneuvers on the mobilization of 59Fe by PIH from the cells were studied. The fate of [14C]-PIH in the in vitro system was also studied. Studies were also carried out using a crude mitochondrial fraction. The results indicate three phases in the iron mobilizing activity of PIH: (1) the entry of PIH into erythroid cells seems to be by passive diffusion; (2) chelation occurs mainly from mitochondria and may depend on the availability of iron in a low molecular weight, non-heme pool. Chelation seems to be enhanced by reduction of Fe (III) to Fe (II); (3) the exit of the PIH2-Fe complex is an energy-dependent process. Iron mobilization by PIH is not dependent on (Na+ + K+)-ATPase activity, external ionic composition, or external hydrogen ion concentration. Membrane fluidity does not seem to play a role in PIH-Fe mobilization. The exit of the PIH2-Fe complex is inhibited by anti-microtubule agents (vinca alkaloids but not colchicine) suggesting that the PIH2-Fe complex is actively extruded from the cell by a microtubule-dependent event.
Collapse
|