The present investigation sought to determine the cellular mechanisms directly dependent on long-term severe sepsis/septic shock that could lead to myocardial structural changes in humans. Human hearts from eight cases of long-term severe sepsis/septic shock arising from infection, as defined by the ACCP/SCCM Consensus Conference; eight cases of acute necrotizing pancreatitis and acute lung injury, a noninfectious pathologic cause of systemic inflammatory response; and three cases of accidental death without thoracic injury selected from autopsies were studied. Transmural blocks of myocardial tissue were excised from the middle portion of the left ventricular free wall and were fixed in formalin or were frozen. Histochemical and immunohistochemical methods were used to evaluate the cross-striations of the myocardial cells, the number and size of interstitial macrophages, the intracardiomyocyte accumulation of lipid, the actin/myosin contractile apparatus, and the expression of iNOS, nitrotyrosine, and TNF-α in the myocardia of septic and control hearts. Greater interstitial cellular infiltration composed of larger and elongated macrophages and TNF-α protein expression in myofibers, interstitial macrophage cell types, and smooth muscle cells and endothelial cell in the vessels; intracardiomyocyte lipid accumulation; scattered foci of actin/myosin contractile apparatus disruption; and increased expression for iNOS and nitrotyrosine in myocytes and interstitial macrophage cell types could be observed in long-term human septic myocardium as compared with normal and acute pancreatitis control myocardia. These findings give support to an opinion that structural changes could be responsible for long-term sepsis-induced myocardial dysfunction. The higher number of macrophages, most of them with morphological features of "activation," and TNF-α protein expression could favor the reduction of cardiac function in septic hearts. The intramyocyte lipid accumulation in these hearts very likely reflects myocardium ventricular contractile dysfunction. In addition, the increased expression of iNOS and the evidence for the significant presence of peroxynitrite in cardiomyocytes and interstitial macrophage cell types suggest that oxidative damage may play a role in actin/myosin disruption in the hearts of septic patients.

This review focuses on the short and bewildered history of Brazilian scientist Carlos Chagas's discovery and subsequent developments, the anatomopathological features of chronic Chagas cardiomyopathy (CCC), an overview on the controversies surrounding theories concerning its pathogenesis, and studies that support the microvascular hypothesis to further explain the pathological features and clinical course of CCC. It is our belief that knowledge of this particular and remarkable cardiomyopathy will shed light not only on the microvascular involvement of its pathogenesis, but also on the pathogenetic processes of other cardiomyopathies, which will hopefully provide a better understanding of the various changes that may lead to an end-stage heart disease with similar features. This review is written to celebrate the 100th anniversary of the discovery of Chagas disease.

Although myocardial depression is the predominant cause of death in severe sepsis/septic shock, it remains disputed whether the functional changes are a consequence of structural alterations. If we look at myocardial dysfunction from the perspective of a critically ill patient, there are a few questions to be asked: What causes myocardial dysfunction? What is the pathophysiology of cardiac dysfunction and death? Is there something that could be done to prevent the outcome? Each of these questions is interrelated and the answers will be more easily addressed if we continue to understand the basic mechanisms that are implicated. The principal mechanisms proposed for the pathogenesis of myocardial dysfunction support a prominent role for functional rather than anatomical abnormalities. However, attempts to reduce the high mortality in septic patients by manipulating the functional alterations have provided limited success. In recent years, the concept of septic cardiomyopathy has evolved, which implies alterations in the myocardial phenotype. This review includes an overview on the activation of the immune system and therapeutic approaches in sepsis, myocardial structural changes in the human septic heart, experimental models of sepsis, and cellular, molecular and functional myocardial changes seen in a variety of experimental sepsis models. The abnormal parameters discussed may emerge as therapeutic targets, for which modulation might provide beneficial effects on cardiovascular outcome and mortality in sepsis in the future.

Heart failure (HF) is characterized by elevated sympathetic activity and reduced parasympathetic control of the heart. Experimental evidence suggests that the increase in parasympathetic function can be a therapeutic alternative to slow HF evolution. The parasympathetic neurotransmission can be improved by acetylcholinesterase inhibition. We investigated the long-term (4 wk) effects of the acetylcholinesterase inhibitor pyridostigmine on sympathovagal balance, cardiac remodeling, and cardiac function in the onset of HF following myocardial infarction. Myocardial infarction was elicited in adult male Wistar rats. After 4 wk of pyridostigmine administration, per os, methylatropine and propranolol were used to evaluate the cardiac sympathovagal balance. The tachycardic response caused by methylatropine was considered to be the vagal tone, whereas the bradycardic response caused by propranolol was considered to be the sympathetic tone. In conscious HF rats, pyridostigmine reduced the basal heart rate, increased vagal, and reduced sympathetic control of heart rate. Pyridostigmine reduced the myocyte diameter and collagen density of the surviving left ventricle. Pyridostigmine also increased vascular endothelial growth factor protein in the left ventricle, suggesting myocardial angiogenesis. Cardiac function was assessed by means of the pressure-volume conductance catheter system. HF rats treated with pyridostigmine exhibited a higher stroke volume, ejection fraction, cardiac output, and contractility of the left ventricle. It was demonstrated that the long-term administration of pyridostigmine started right after coronary artery ligation augmented cardiac vagal and reduced sympathetic tone, attenuating cardiac remodeling and left ventricular dysfunction during the progression of HF in rats.

Chagas disease, caused by the parasite Trypanosoma cruzi, is an important cause of cardiac disease in endemic areas of Latin America. It is now being diagnosed in nonendemic areas because of immigration. Typical cardiac manifestations of Chagas disease include dilated cardiomyopathy, congestive heart failure, arrhythmias, cardioembolism, and stroke. Clinical and laboratory-based research to define the pathology resulting from T. cruzi infection has shed light on many of the cellular and molecular mechanisms leading to these manifestations. Antiparasitic treatment may not be appropriate for patients with advanced cardiac disease. Clinical management of Chagas heart disease is similar to that used for cardiomyopathies caused by other processes. Cardiac transplantation has been successfully performed in a small number of patients with Chagas heart disease.