Cell death, proliferation and repair in human myocarditis responding to immunosuppressive therapy

Abstract

In this study, we evaluate cell death, proliferation and repair in left ventricular endomyocardial biopsies from 20 patients with active lymphocytic myocarditis worsening or recovering from cardiac dysfunction after 6-months immunosuppression. Apoptosis and necrosis were assessed by in situ ligation of hairpin probes, proliferation by Ki67 and MCM5 labelling of myocytes, repair by electron microscopy, morphometric study of percent myofibrillar area and real-time polymerase chain reaction of a-and b-Myosin Heavy Chain (MHC). Apoptosis and necrosis decreased in post-vs pretreatment biopsies by 85 and 62%, respectively in responders, while increased by 42 and 46% in nonresponders. Ki67 and MCM5-positive myocytes were higher vs controls at baseline and increased by 43 and 38% at follow-up in responders and by 75 and 63% in nonresponders. Myofibrillar area reduced in pretreatment samples, increased by 33% at follow-up in responders, correlated with percent enhancement of ejection fraction and was associated with increased a-MHC expression and a/b-MHC ratio. In follow-up biopsies of nonresponders, myofibrillar area diminished by 36% and correlated with percent decrease of ejection fraction. Our results suggest that recovery of cardiac function in myocarditis responding to immunosuppression is associated with inhibition of cell death, activation of cell proliferation and with newly synthesized contractile material. Keywords: myocarditis; heart failure; immunosuppressive therapy; apoptosis; myofibrillolysis; cell repair It has been recently shown that immunosuppression can be an effective therapeutic option in active lymphocytic myocarditis, 1,2 characterized by the presence of circulating serum cardiac autoantibodies and undetectable viral agents at the PCR evaluation of frozen endomyocardial samples. Cell mechanisms of cardiac recovery are, however, still speculative and may include halting of proteolysis and cell death, activation of cell proliferation and reconstitution of cell myofibrillar content. The contribution of each of these mechanisms has not yet been analyzed, while its definition may identify new strategies for the treatment of heart failure.The aim of this study is a morphologic, morphometric and molecular evaluation of cell death, cell proliferation and repair in sequential endomyocardial biopsies of patients with myocarditis and heart failure, deteriorating and recovering, respectively, after immunosuppressive therapy. Materials and methods Patient SelectionAmong 41 patients that at our Institution from January 1997 to July 2000 were treated for 6 months with immunosuppressive therapy (prednisone 1 mg kg À1 day À1 for 4 weeks followed by 0.33 mg kg À1 day À1 for 5 months and azathioprine 2 mg kg À1 day À1 for 6 months) in addition to full conventional therapy with digitalis, diuretics, ACE inhibitors and carvedilol because of active lymphocytic

Probiotic Sonicates Selectively Induce Mucosal Immune Cells Apoptosis through Ceramide Generation via Neutral Sphingomyelinase

“…The clinical relevance of immune cell apoptosis in IBD is supported by evidence showing that induction of apoptosis is a mechanism common to most IBD therapies, including aminosalycilates (12), steroids (13), immunosupressants [40], and infliximab [41]. In conclusion, the ability of L. brevis and S. thermophilus to promote apoptosis may compensate the deficient cell death and thus contribute to re-establish mucosal immune homeostasis and decrease inflammation in IBD-involved intestine.…”

Increased myocardial expression of Toll-like receptors 2 and 9 as a marker of active myocarditis and a possible predictor of therapeutic effectiveness

“…Низкий уровень виментина, отражающий, вероятно, степень утраты КМЦ, свидетельствует об отсутствии резервов для улучшения. Нами не выявлено корреляции ответа на ИСТ с возрастанием маркеров пролиферации (Ki-67), что согласуется с данными литературы о возрастании их экспрессии не только у больных с хорошим ответом на ИСТ, но и без него, правда в меньшей степени [9].…”

“…Наконец, представлялось целесообразным оценить экспрессию маркеров клеточной пролиферации, поскольку имеются сведения об активизации стволовых клеток сердца в рамках миокардита [7]. Экспрессия Ki-67 традиционно используется в онкологии для определения индекса пролиферации опухолей, однако в отдельных работах ее возрастание установлено и при миокардитах в сравнении со здоровым сердцем [8][9][10]. Недавно в эксперименте на мышах изучена роль c-kit-позитивных прогениторных клеток в развитии Коксакивирусного миокардита [11]: у ювенильных мышей эти клетки активно продуцировали вирусный материал и погибали посред-the patients (Group 1) and in 6 patients (Group 2) in conjunction with the underlying disease (only in 9 and 7 patients, respectively), viral genome was detected in the myocardium of 15 patients, including in 5 without morphological signs of myocarditis (parvovirus B19 (n=11), herpesvirus 6 (n=4), herpes simplex virus types 1 and 2 (n=1), Epstein-Barr virus (n=2), and cytomegalovirus (n=1)), and in the blood (n=4).…”

The Role of Immunity Suppression in Treatment of Myocarditis

“…Клеточные механизмы восстановления сердца У получавших иммуносупрессию больных с вос-палительной кардиомиопатией были также проана-лизированы клеточные механизмы восстановления сердца, включая клеточную смерть, активацию кле-точной пролиферации и реконструкцию содержания клеточных миофибрилл [32], для уточнения эффекта клеточного восстановления по сравнению с проли-ферацией клеток или возможного участия ингибиро-вания клеточной смерти.…”