Heme oxygenase-1 expression in the left atrial myocardium of patients with chronic atrial fibrillation related to mitral valve disease: its regional relationship with structural remodeling

• Published in: Human pathology Vol. 39; no. 8; pp. 1162 - 1171
• Main Authors: Corradi, Domenico, MD, Callegari, Sergio, MD, Maestri, Roberta, BsSc, PhD, Benussi, Stefano, MD, PhD, Bosio, Silvia, MD, De Palma, Giuseppe, MD, Alinovi, Rossella, BsSc, Caglieri, Andrea, BsSc, PhD, Goldoni, Matteo, PhD, Mozzoni, Paola, BsSc, PhD, Pastori, Paolo, MD, Manotti, Laura, MD, Nascimbene, Simona, MD, Dorigo, Enrica, MD, Rusconi, Raffaella, BsSc, Astorri, Ettore, MD, Alfieri, Ottavio, MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.08.2008; Elsevier; Elsevier Limited
• Subjects: Adult; Aged; Aged, 80 and over; Antioxidants; Atrial fibrillation; Atrial Fibrillation - enzymology; Atrial Fibrillation - etiology; Atrial Fibrillation - pathology; Atrial Function; Biological and medical sciences; Capillaries - pathology; Cardiac arrhythmia; Cardiac dysrhythmias; Cardiology. Vascular system; Chronic Disease; Colleges & universities; Disease; Enzyme-Linked Immunosorbent Assay; Female; Heart; Heart Atria - enzymology; Heart attacks; Heme oxygenase-1; Heme Oxygenase-1 - metabolism; Hospitals; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Mitral valve disease; Mitral Valve Insufficiency - complications; Mitral Valve Stenosis - complications; Mortality; Myocardium - enzymology; Myocardium - pathology; Oxidative Stress; Pathology; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Proteins; Reverse Transcriptase Polymerase Chain Reaction; Rodents; Sinuses; Structural remodeling; Surgery; Veins & arteries; Oxidative stress; Mitral valve disease; Atrial fibrillation; Structural remodeling; Heme oxygenase-1; Human; Arrhythmia; Enzyme; Heme oxygenase (decyclizing); Cardiovascular disease; Left atrium; Regional; Remodeling; Excitability disorder; Anatomic pathology; Chronic; Cardiac valvular disease; Heat shock protein; Myocardium; Circulatory system; Oxidoreductases
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2007.12.007

Summary Atrial fibrillation becomes a self-perpetuating arrhythmia as a consequence of electrophysiogic and structural remodeling involving the atrium. Oxidative stress may be a link between this rhythm disturbance and electrophysiogic remodeling. The aim of this study was to evaluate whether the heme oxygenase-1 (HO-1) marker of oxidative stress was more expressed in left atrial sites with stronger structural remodeling in patients affected by chronic atrial fibrillation (CAF) and mitral valve disease (MD). Myocardial samples were taken from the left atrial posterior wall (LAPW) and left atrial appendage (LAA) of 24 patients with CAF-MD in addition to 10 autopsy controls. The levels of HO-1 messenger RNA (mRNA) and HO-1 protein in each pathologic LAPW and LAA were quantified using reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. Furthermore, light microscopy was used to morphometrically evaluate the differential myocyte and interstitial changes in the same CAF-MD LAPW and LAA samples. In controls, HO-1 protein was quantified using enzyme-linked immunosorbent assay. Unlike controls, patients with CAF-MD had higher levels of HO-1 mRNA and its protein product, expressed as LAPW/LAA ratios, in the LAPW (2.18 ± 1.18, P < .0001, and 1.55 ± 0.67, P < .005), and their LAPW also showed greater histologic changes in myocytolytic myocytes (15.1% ± 3.1% versus 6.9% ± 3.3%, P < .0001), interstitial fibrosis (8.2% ± 2.2% versus 2.8% ± 1.2%, P < .0001), and capillary density (816 ± 120 number/mm2 versus 1114 ± 188 number/mm2 ; P < .05). In addition, markers of oxidative stress were immunohistochemically studied with antinitrotyrosine and anti-iNOS antibodies. In patients with CAF-MD, the inducible enzyme HO-1 is more expressed in the left atrial areas that show greater structural remodeling. This finding strongly suggests a pathogenetic relationship between oxidative stress and the degree of histologic change.