1. Expression of High Mobility Group Protein B1 in Cardiac Tissue of Elderly Patients with Coronary Artery Disease with or without Inflammatory Rheumatic Disease
- Author
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Cecilia Wick, Helena Erlandsson Harris, Stein Erik Rynning, Kjell Saatvedt, Julie Xiao, Eva Lindroos, Mei Bruton, Ingrid E. Lundberg, Knut Mikkelsen, Sven M. Almdahl, and Ivana Hollan
- Subjects
Male ,0301 basic medicine ,Aging ,medicine.medical_specialty ,Blotting, Western ,Receptor for Advanced Glycation End Products ,chemical and pharmacologic phenomena ,Coronary Artery Disease ,030204 cardiovascular system & hematology ,HMGB1 ,Coronary artery disease ,03 medical and health sciences ,0302 clinical medicine ,Rheumatic Diseases ,Internal medicine ,parasitic diseases ,Humans ,Medicine ,Myocytes, Cardiac ,HMGB1 Protein ,Receptor ,Aged ,biology ,business.industry ,Myocardium ,Middle Aged ,medicine.disease ,Coronary Vessels ,Immunohistochemistry ,Toll-Like Receptor 2 ,Toll-Like Receptor 4 ,TLR2 ,030104 developmental biology ,Heart failure ,biology.protein ,Cardiology ,TLR4 ,Female ,Geriatrics and Gerontology ,Signal transduction ,business ,Pericardium ,Endocardium - Abstract
Background: It is known from clinical practice and observational studies that elderly patients with a diagnosis of inflammatory rheumatic diseases (IRD) bear a significantly increased risk for cardiovascular diseases such as coronary artery disease (CAD) and heart failure. The molecular mechanism, however, is still not known. Recently, high mobility group protein B1 (HMGB1), a ubiquitous, highly conserved single polypeptide expressed in all mammal eukaryotic cells, has been identified to mediate myocardial dysfunction in vitro once released from the nuclei of cardiomyocytes. Objective: To investigate whether HMGB1 and its receptors are expressed in cardiac muscles of elderly patients with CAD with or without IRD. Methods: HMGB1 and its 3 well-known receptors, receptor for advanced glycation end products, Toll-like receptor 2 (TLR2), and TLR4, were examined by immunohistochemistry on myocardial biopsy specimens from 18 elderly patients with CAD (10 with IRD, 8 without IRD). Furthermore, total HMGB1 protein levels were measured by Western blot from the cardiac biopsies in 5 patients with and 5 without IRD. Results: Pathologic cytosolic HMGB1 in cardiomyocytes was massively recorded in all patients with IRD, but only slightly expressed in 1 patient without IRD. Total HMGB1 levels were also consistently lower in myocardial muscle biopsies of patients with IRD compared to those without IRD. Furthermore, all 3 HMGB1 receptors were expressed in cardiomyocytes of all patients. Conclusion: The increased cytosolic expression of HMGB1 in cardiomyocytes and the lower total amount of HMGB1 in the cardiac specimens of IRD patients is consistent with a greater release of HMGB1 from the myocardial nuclei in IRD than non-IRD individuals. Thus, the HMGB1 signaling pathways may be more easily activated in elderly CAD patients with concomitant IRD and trigger a detrimental inflammatory process causing severe cardiovascular problems. Therefore, targeting HMGB1 in IRD patients might reduce the risk for cardiovascular events.
- Published
- 2017
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