Search

Air pollution is a complex mixture of particulate matter and gases linked to adverse clinical outcomes. As such, studying responses to individual pollutants does not account for the potential biological responses resulting from the interaction of various constituents within an ambient air shed. We previously reported that exposure to high levels of the gaseous pollutant acrolein perturbs myocardial synchrony. Here, we examined the effects of repeated, intermittent co-exposure to low levels of concentrated ambient particulates (CAPs) and acrolein on myocardial synchrony and the role of transient receptor potential cation channel A1 (TRPA1), which we previously linked to air pollution-induced sensitization to triggered cardiac arrhythmia. Female B6129 and Trpa1-/- mice (n = 6/group) were exposed to filtered air (FA), CAPs (46 µg/m3 of PM2.5), Acrolein (0.42 ppm), or CAPs+Acrolein for 3 h/day, 2 days/week for 4 weeks. Cardiac ultrasound was conducted to assess cardiac synchronicity and function before and after the first exposure and after the final exposure. Heart rate variability (HRV), an indicator of autonomic tone, was assessed after the final exposure. Strain delay (time between peak strain in adjacent cardiac wall segments), an index of myocardial dyssynchrony, increased by 5-fold after the final CAPs+Acrolein exposure in B6129 mice compared with FA, CAPs, or Acrolein-exposed B6129 mice, and CAPs+Acrolein-exposed Trpa1-/- mice. Only exposure to acrolein alone increased the HRV high frequency domain (5-fold) in B6129 mice, but not in Trpa1-/- mice. Thus, repeated inhalation of pollutant mixtures may increase risk for cardiac responses compared with single or multiple exposures to individual pollutants through TRPA1 activation.

We have previously shown that resting energy expenditure (REE) adjusted by fat-free mass (FFM) in male college athletes remains consistent regardless of FFM. The FFM comprises internal organs with high metabolic activity, such as liver and brain, which account for 60 to 80% of REE in adults. The purpose of the present study is to examine the contribution of internal organs to the REE of the FFM fraction among male power athletes. The study included 37 American male college football players. REE was measured by indirect calorimetry and body composition was measured by dual energy X-ray absorptiometry (DXA). Mass of brain, liver, and kidneys was measured by MRI and mass of heart was estimated by echocardiography. Normal levels of thyroid hormone (triiodothyronine: T3) were confirmed in all subjects prior to the analysis. Multiple regression analysis was used to assess the influence of FFM, fat mass (FM), T3, and mass of organs on variance of REE. Average body weight and FFM were 81.2±11.3 kg and 67.7±7.4 kg, respectively. The relative contributions of liver, kidneys, and heart to REE were consistent regardless of FFM, while the REE of brain was negatively correlated with FFM (r=-0.672, p<0.001). Only FFM and T3 were found to be independent factors influencing REE. These results suggest that a steady contribution of internal organs other than the brain is the major reason for the consistency of the REE/FFM ratio in male power athletes.

Chronic rejection currently limits the long-term efficacy of clinical transplantation. Although B cells have recently been shown to play a pivotal role in the induction of alloimmunity and are being targeted in other transplant contexts, the efficacy of preemptive B cell depletion to modulate alloimmunity or attenuate cardiac allograft vasculopathy (CAV) (classic chronic rejection lesions found in transplanted hearts) in a translational model has not previously been described. We report here that the CD20-specific antibody (alphaCD20) rituximab depleted CD20+ B cells in peripheral blood, secondary lymphoid organs, and the graft in cynomolgus monkey recipients of heterotopic cardiac allografts. Furthermore, CD20+ B cell depletion therapy combined with the calcineurin inhibitor cyclosporine A (CsA) prolonged median primary graft survival relative to treatment with alphaCD20 or CsA alone. In animals treated with both alphaCD20 and CsA that achieved efficient B cell depletion, alloantibody production was substantially inhibited and the CAV severity score was markedly reduced. We conclude therefore that efficient preemptive depletion of CD20+ B cells is effective in a preclinical model to modulate pathogenic alloimmunity and to attenuate chronic rejection when used in conjunction with a conventional clinical immunosuppressant. This study suggests that use of this treatment combination may improve the efficacy of transplantation in the clinic.

Myocyte diameter, fractional area of collagen, intensity of myocarditis and parasite persistence (explored by immunohistochemistry and PCR) were evaluated in serial sections of endomyocardial biopsies from 29 outpatients with chronic chagasic cardiopathy. The patients, 25 males and four females with a mean (S.D.) age of 43 (9) years, were subsequently followed up for 3-2861 days (median=369 days). During this follow-up, 16 (55%) of the patients died. The biopsies revealed myocarditis in 25 (86%) of the patients and high-grade myocarditis in 14 (56%). Although immunohistochemistry failed to demonstrate Trypanosoma cruzi antigens in any of the samples, five (33%) of the 15 biopsies successfully tested in the PCR-based assay for T. cruzi DNA were found positive, indicating parasite persistence. There was a significant positive association between myocardial parasite persistence and high-grade myocarditis (P=0.014); five (71%) of the seven endomyocardial biopsies with high-grade myocarditis that were successfully tested in the PCR assays showed persistent T. cruzi DNA. The survival time of the patients was not, however, found to be significantly associated with myocardial parasite persistence, any of the morphometric measurements taken, or the presence or intensity of myocarditis.

Human chronic Chagas disease cardiomyopathy (CCC) is an inflammatory-dilated cardiomyopathy occurring years after infection by the protozoan Trypanosoma cruzi. The heart inflammatory infiltrate in CCC shows a 2:1 predominance of CD8(+) in relation to CD4(+) T cells, with a typical Th1-type cytokine profile. However, in vitro expansion of infiltrating T cells from heart biopsy-derived fragments with interleukin-2 (IL-2) and phytohaemagglutinin leads to the outgrowth of CD4(+) over CD8(+) T cells. We hypothesized that survival cytokines, such as IL-2, IL-7 and IL-15 might be differentially involved in the growth and maintenance of heart-infiltrating and peripheral CD8(+) T cells from CCC patients. We found that IL-7 and IL-15 were superior to IL-2 in the expansion and viability of CD8(+) T cells from both PBMC and heart-infiltrating T-cell lines from CCC patients, and the combination of the three cytokines showed synergic effects. Heart-infiltrating CD8(+) T cells showed higher expression of both IL-15R alpha and gamma(c) chain than CD4(+) T cells, which may explain the improvement of CD8(+) T-cell growth in the presence of IL-2 + IL-7 + IL-15. Immunohistochemical identification of IL-15 and the higher mRNA expression of IL-15R alpha, IL-7 and gamma(c) chain in CCC heart tissues compared with control individuals indicate in situ production of survival cytokines and their receptors in CCC hearts. Together, our results suggest that local production of IL-7 and IL-15 may be associated with the maintenance and predominance of CD8(+) T cells, the cells effecting tissue damage in CCC hearts.

Hypertension is a major risk factor for cardiovascular disease. Thus, prevention of hypertension and consequent organ damage is important for reducing its incidence. In the present study, we examined the involvement of tissue inhibitor of metalloproteinase-3 (Timp-3) in N(omega)-nitro-L-arginine methyl ester (L-NAME)-induced hypertension and accompanying vascular remodeling in mice. L-NAME was orally administered to wild-type (WT) and Timp-3 knockout (KO) mice for 6 weeks, blood pressure was monitored, and histological changes in myocardial arteries were examined. After L-NAME administration, blood pressure was lower in Timp-3 KO mice than in WT mice. The coronary arteries of WT and Timp-3 KO mice were similar after L-NAME treatment and showed no differences compared to untreated control mice. However, cardiac microvessels differed histologically between WT and Timp-3 KO mice. Vascular walls were less thickened in Timp-3 KO than in WT mice, and fibrotic changes were significantly reduced in Timp-3 KO mice. Moreover, the L-NAME-induced production of reactive oxygen species in cardiac microvessels was lower in Timp-3 KO than in WT mice. These results indicate that Timp-3 plays an important role in L-NAME-induced hypertension and myocardial vascular remodeling. Our findings suggest that Timp-3 may be a novel therapeutic target for the treatment of hypertension and consequent organ damage.

American trypanosomiasis (Chagas' disease [CD]) caused by Trypanosoma cruzi is endemic in Latin America, where it is one of the leading causes of death. The involvement of the heart is crucial in the patients' prognosis. Besides lymphocytic myocarditis, cardiomyopathy is associated with several degrees of myocardial fibrosis (MF). Myocardial delayed enhancement by cardiac magnetic resonance (CMR) has been considered the most accurate method to detect MF in ischemic and nonischemic cardiomyopathy, including Chagas' heart disease. Additionally, CMR offers a wide variety of imaging tools to evaluate in detail morphology, the function and other tissue characterization abilities, such as detection of edema and fat. The present article aims to discuss the current clinical applicability of CMR to evaluate CD. We also discuss its future as a screening tool for very early myocardial involvement, which would allow the investigation of new therapeutic methods with potential influence in the natural history of CD.

Objectives: Late treatment with erythropoietin (EPO), as well as the administration before the onset of or during the acute stage of myocardial infarction (MI), has recently been shown to mitigate post-MI heart failure. We investigated the mechanisms, including the downstream signaling pathways, for the beneficial effect of late treatment with EPO on chronic post-MI heart failure., Methods and Results: EPO (1500 U/kg, twice a week) was administered to mice beginning 6 weeks after induction of large MI. The EPO treatment for 4 weeks diminished left ventricular dilatation and improved function. It significantly reduced inflammatory cell infiltration and fibrosis, and increased vascular density in noninfarcted areas. The elevated levels of the inflammatory cytokines interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha and transforming growth factor-beta1 seen in the failing hearts were returned nearly to control levels by EPO treatment. Oxidative damage in surviving cardiomyocytes was also significantly attenuated by EPO. Expression of EPO receptor was upregulated in failing hearts, and EPO treatment led to myocardial activation of signal transducer and activator of transcription-3 (Stat3), Stat5, and Akt. These in vivo effects of EPO were confirmed in vitro in experiments that showed the anti-inflammatory and anti-oxidant effects of EPO to be mediated via Stat and Akt activation. Finally, the beneficial effects of EPO were found to persist for 4 weeks after discontinuing treatment., Conclusions: It thus appears that Stat-mediated reduction of inflammation and cytokine production and Akt-mediated attenuation of oxidative stress accompany the beneficial effects of late treatment with EPO on chronic post-MI heart failure.

Bradykinin may interfere with myocardial remodelling by promoting inflammation and mast cell activation or, alternatively, by counteracting angiotensin II-dependent collagen accumulation. The aim of the present study was to investigate the role of bradykinin B2 receptor antagonism in inflammatory and mast cell infiltration, fibroplasia and fibrosis accumulation following myocardial infarction (MI). Myocardial infarction was produced by the ligature of the left coronary artery in male Wistar rats that were 10 weeks of age. Immediately after MI, rats received the B2 receptor antagonist Hoe140 (0.5 microg/kg per min, s.c.) or saline over a period of 3 days, 1 week or 4 weeks, constituting three separate groups and their respective controls. Coronal myocardial tissue sections underwent haematoxylin and eosin, Giemsa and picrosirius red staining, as well as immunohistochemistry for alpha-smooth muscle actin (SMA). Morphometric studies were undertaken in three different myocardial regions: MI, remote non-infarcted subendocardium (non-MI SE) and remote non-infarcted interventricular septum (non-MI IVS). The MI size was comparable between Hoe140-treated groups and their respective controls (day 3: 42 +/- 4%, n = 8, vs 43 +/- 3%, n = 6; week 1: 37 +/- 5%, n = 5, vs 39 +/- 2%, n = 5; week 4: 35 +/- 3%, n = 9, vs 36 +/- 3%, n = 7). At day 3, Hoe140 treatment reduced inflammatory cell reaction within the MI (585 +/- 59 vs 995 +/- 170 cells/mm2; P = 0.02), non-MI SE (77 +/- 12 vs 214 +/- 57 cells/mm2; P = 0.02) and non-MI IVS (93 +/- 16 vs 135 +/- 14 cells/mm2; P = 0.03) regions. Mast cells were reduced within the non-MI IVS region (0.8 +/- 0.1 vs 2.5 +/- 0.4 cells/mm2; P = 0.006), but not within the MI region. In non-MI SE, mast cells were rarely found. At week 1, Hoe140 treatment reduced alpha-SMA-positive myofibroblast infiltration within the MI (2535 +/- 383 vs 5636 +/- 968 cells/mm2; P = 0.01) and non-MI SE (222 +/- 33 vs 597 +/- 162 cells/mm2; P = 0.03) regions. In the non-MI IVS region, alpha-SMA-positive myofibroblasts were rarely found. At week 4, Hoe140 treatment reduced collagen volume fraction within the MI (37 +/- 4 vs 53 +/- 4%; P = 0.03), non-MI SE (1.3 +/- 0.2 vs 2.6 +/- 0.3%; P = 0.001) and non-MI IVS (1.1 +/- 0.2 vs 1.8 +/- 0.2%; P = 0.01) regions. Bradykinin promotes inflammation, fibroplasia and fibrosis after MI. Mast cells may have a role in fibrosis deposition through a bradykinin-related mechanism.

The sympathetic nervous systems may bear relevance to the increased incidence of heart failure in diabetes (DM). In our isolated rat hearts perfused at constant low flow rate, norepinephrine dose-dependently enhanced diabetic myocardial damage, particularly during underperfusion. The purpose of this investigation is to examine the effects of epinephrine on the ischemic injury and on the reperfusion injury in DM and non-DM rat hearts, and to clarify whether the cardiac states during underperfusion at constant low pressure are similar to those at constant low flow rate. Isolated streptozotocin-induced 6-week DM and non-DM rat hearts with a balloon in the left ventricle (LV) were paced and normal perfused at 75 cm H2O with normoxic Krebs-Henseleit solution. Then the hearts were underperfused at 35 cm H2O, a constant low pressure with below one-third of the pre-ischemic coronary perfusion flow (CPF) level. Four min after the start of underperfusion, the perfusate was changed to that containing epinephrine 10(-6) M. After 45 min underperfusion with or without epinephrine, all of the hearts were reperfused without epinephrine at 75 cm H2O for 45 min. To detect changes in LV stiffness, the isometric tension along the longitudinal direction of the whole heart and the LV isovolumic pressure were monitored simultaneously. In DM hearts, the underperfusion alone caused a slight increase in LV stiffness, and all the changes recovered to the pre-ischemic levels during reperfusion. Epinephrine during underperfusion accelerated the start of increase in LV stiffness and the decrease in CPF. During reperfusion the changes recovered partly to the control levels. In non-DM hearts, epinephrine during underperfusion caused only a slight increase in LV stiffness though a similar low CPF to DM hearts. However, the reperfusion caused a marked increase in LV stiffness and a lower recovery of CPF. Epinephrine at constant low pressure, as well as norepinephrine at constant low flow rate, enhanced the ischemic injury, particularly in DM hearts, while aggravated the reperfusion injury in non-DM hearts.

The influence of coenzyme Q10 (CoQ10) in cold stress test (-15 degrees C for 4 hours) cardiac functional impairment was studied in isolated isovolumic heart of control rats (C; n=12) and of placebo (P; n=11) and treated rats (CoQ10; n=10). In addition, electron microscopic evaluation of left ventricular (LV) slices (n=3 in each group) allowed us to analyze the myocardial ultrastructure. Maximal values of developed pressure (DPmax) were similarly decreased in cold stressed animals (C=129+/-3.9 mmHg; P=106+/-6.7 mmHg; CoQ10=91+/-3.9 mmHg); however, volume-induced enhancement of pressure generation (slope of DP volume relations: C=0.248+/-0.0203 mmHg / microl; P=0.2831+/-0.0187 mmHg / microl; CoQ10=0.2387 ( 0.0225 mmHg / microl; p > 0.05), and the duration of systole (C=80+/-1.6 ms; P=78+/-1.3 ms; CoQ10=80+/-2.7 ms) were not altered. Myocardial relaxation, evaluated by the relaxation constant (C=39+/-1.9 ms; P=42+/-3.4 ms; CoQ10=51+/-6.0 ms), as well as resting stress / strain relations were unaffected by cold stress. Myocardial samples showed that pretreatment with CoQ10 attenuates myofibrillar and mitochondrial lesions, and prevents mitochondrial fractional area increase (P: 53.11%>CoQ10: 38.78%=C: 33.87%; p< 0.005) indicating that the exogenous administration of CoQ10 can reduce cold stress myocardial injury.

In this work we quantified various growth factors in the myocardium of 19 patients with chronic chagasic cardiomyopathy and heart failure, through the immunoperoxidase technique. We looked for T. cruzi antigens, growth factors (GM-CSF, TGF-beta1, PDGF-A and PDGF-B) and inflammatory cells (CD4+, CD8+, CD20+ and CD68+). The mean ratio of CD4+/CD8+ T lymphocytes was 0.6 +/- 0.3. The mean number of positive interstitial cells was 5.9 +/- 3.1 for CD68+ (macrophages); 7.5 +/- 4.3 for PDGF-A+; 2.9 +/- 2.7 for PDGF-B+, 2.2 +/- 1.9 for TGF-beta1+ and 2.3 +/- 1.9 for GM-CSF+. The immunoreaction for PDGF-A was intense, occurring also in the endothelium, smooth muscle cells and the sarcolemma; there was no correlation between the number of positive interstitial cells and the semiquantitation of the same growth factors in the other cells. TGF-beta1 presented low expression in 100% of the cases. In conclusion, PDGF-A and B are probably the growth factors most related to the proliferative lesions and fibrosis present in chronic chagasic cardiomyopathy. GM-CSF and TGF-beta1 are present in low levels. There was no statistical correlation between growth factors and the quantity of the parasitic antigens.

The immunohistochemical expression of adhesion molecules and class I HLA in chronic chagasic cardiomyopathy were compared with heart allograft rejection and dilated cardiomyopathy, to obtain new knowledge on the occurrence of autoimmunity and inflammation in the pathogenesis of chronic chagasic cardiomyopathy. Semiquantitative immunohistochemistry was performed for CD8+ T cells, ICAM-1, VCAM-1, LFA-1, and class I HLA in frozen sections of myocardial biopsies from patients presenting chronic chagasic cardiomyopathy (group I, n = 12), heart allograft rejection (group II, n = 9) or dilated cardiomyopathy (group III, n = 9). A high mean number of CD8+ T cells/mm(2) was present in group I (18.26) and group II (28.60), but not in group III (0.83). The frequency of high expression for ICAM-1 and VCAM-1 on the endothelial and interstitial cells, and for class I HLA on the cardiomyocytes was greater in group I (100%, 33.3%, and 83.3%, respectively) and group II (100%, 66.7%, and 77.8%, respectively), compared to group III (66.7%, 0%, and 0%, respectively). ICAM-1 and VCAM-1 probably participate in the development of the lymphocytic inflammatory infiltrate present in chronic chagasic cardiomyopathy, as seen in heart allograft rejection. The overexpression of adhesion molecules and the induction of class I HLA on the cardiomyocytes are probably related to the high cytokine levels at the inflammatory sites in chronic chagasic cardiomyopathy. Although the induction of class I HLA on the cardiomyocytes is consistent with an autoimmune reaction, it should not be considered as irrefutable evidence for autoimmunity in chronic chagasic cardiomyopathy. The differential expression of adhesion molecules and class I HLA in dilated cardiomyopathy compared to chronic chagasic cardiomyopathy suggests differences in the pathogenesis of these cardiomyopathies.

Background: Despite the initial promissory results of partial left ventriculectomy, or Batista's operation, the postoperative mortality associated with the procedure has been too high. We described a histopathologic study performed to identify histological parameters that could help to determine outcomes of patients undergoing this procedure., Methods and Results: Myocardial fiber diameter, myocardial fibrosis, thickness of the compact wall, and number of cells presenting from the endocardium to epicardium were analyzed in 32 patients with idiopathic dilated cardiomyopathy who underwent Batista's operation. Data were grouped by patients who died < or = 6 months and patients who survived for > 6 months after the surgical procedure. Additional analyses were performed to compare results according the causes of death and to test the application of these results to biopsy., Results: Myocardial fiber diameter was the only index that could distinguish the two groups. Myocardial fiber diameter < 22 microm distinguished the group of patients who survived the 6-month postoperative period from patients who died during that time with sensitivity of 85.7 and specificity of 72.2. The subendocardial region of the compact wall and the trabecular portion of the wall exhibited comparable results., Conclusion: Our results indicate that the myocardial fiber diameter of samples from the trabecular or subendocardial compact wall regions may help predict the outcome of left ventriculectomy. Samples from the trabecular or subendocardial compact wall regions were used for analysis. Further prospective studies involving left ventricular endomyocardial biopsies are necessary to confirm if the use of myocardial fiber diameter in the selection of patients for surgery improves the index of success of Batista's operation. Other factors that are involved remain unclear.

Expression and distribution of atrial natriuretic peptide (ANP) were studied immunohistochemically in the conducting system and internodal atrial myocardium of 5 adult human hearts. Myocytes from the sinus node and compact atrioventricular node were usually ANP-negative; only a very few cells exhibited ANP immunoreactivity. These ANP-positive myocytes were small and did not appear to be trapped working atrial myocytes which are larger than nodal cells. The transitional cell zones of the sinus node and the atrioventricular node were composed of bundles of ANP-positive myocytes, intermingled with non-reactive myocytes. The internodal atrial myocardium exhibited a comparable intensity of myocyte staining in each case examined. Thus, morphologically distinct connecting pathways between the sinus node and the atrioventricular node with regard to myocyte ANP immunoreactivity could not be demonstrated, reinforcing the notion that they actually do not exist. The penetrating bundle, branching bundle and bundle branches were usually composed of ANP-negative myocytes although some ANP-positive myocytes were observed in the branching bundle and bundle branches in 4 cases. Myocytes from the ventricular conducting tissue presenting ANP immunoreactivity have been designated Purkinje fibers and have been found in several mammalian species.

The relationship between cardiac dysfunction and glycogen level and/or duration of diabetes was examined during underperfusion (2 ml/min/g heart weight) with 10(-6)M norepinephrine (NE) in isolated 1- and 6-week streptozotocin-diabetic rat (diabetes mellitus, DM) hearts and non-DM hearts. Glycogen levels in non-DM and 1- and 6-week DM hearts were 85, 120, and 206 mumol/g dry weight, respectively, in the subendocardium. About 13 min after the start of underperfusion with NE, the diastolic tension in 1-week DM hearts began to increase when the glycogen level had decreased to half; in 6-week DM hearts, glycogen decreased more markedly without greater lactate accumulation, but these glycogen levels were still higher (104 mumol/g dry weight) than those in 1-week DM hearts and the diastolic tension did not increase. About 17 min after the onset of underperfusion, the glycogen decreased to the 13-min level of 1-week DM hearts (64 mumol/g dry weight) and the diastolic tension began to increase. Until 20 min after the onset of underperfusion, the injury was less in 6-week than in 1-week DM hearts. However, after 60-min underperfusion with NE, when the glycogen level was markedly low in both groups ( < 20 mumol/g dry weight), diastolic tension was increased twice as much in 6-week DM as in 1-week DM hearts and was related to the decreased subendocardial ATP level. The results indicate that the markedly high glycogen content in diabetic hearts probably helps delay the start of the increase in left ventricular (LV) stiffness during underperfusion with NE. Ultimately, however, the degree of the injury depends on the duration, i.e., the severity, of the diabetes.

Purpose: To study the correlation between magnetic resonance imaging of the heart and right ventricle endomyocardial biopsy results in chronic Chagas' heart disease., Methods: Ten patients with Chagas' disease, mean age 47 +/- 7 years, all males, in congestive heart failure with New York Heart Association class II (2 patients), III (6) and IV (2) were studied. Mean left ventricular ejection fraction was at echocardiogram 36 +/- 6%. The patients were submitted to right ventricular endomyocardial biopsy and magnetic resonance imaging of the heart. The results of this group were compared with a control group of patients with idiopathic dilated cardiomyopathy, with mean age of 46 +/- 10 years and left ventricular ejection fraction of 30 +/- 4%, in heart failure with functional class II (1 patient), III (5) and IV (1)., Results: All patients with Chagas' heart disease presented an increase in magnetic ressonance imaging signal of the heart after gadolinium use. The septal signal intensity changed from 0.87 +/- 0.06 to 1.54 +/- 0.16 (p < 0.001). In the control group the mean septal signal intensity was 0.93 +/- 0.07 before and 0.89 +/- 0.06 after the gadolinium (p = ns). Eight patients of the Chagas' disease group had biopsy proven myocarditis and two had borderline myocarditis. However, only one patient of the control group had diagnosis of borderline myocarditis., Conclusion: Myocarditis is frequently found in Chagas' heart disease patients and who unlike controls present a significant increase in myocardial signal intensity after gadolinium infusion. The magnetic resonance imaging of the heart seems a promising alternative method for the diagnosis of an inflammatory process in Chagas' heart disease.

The role of autoimmunity in the pathogenesis and progression of heart lesions in the chronic phase of Chagas' disease is controversial. In the absence of parasites in situ, the T cell infiltrate seen in heart lesions may be the primary determinant of tissue damage ultimately leading to heart failure and death. We used the polymerase chain reaction to amplify each known T cell receptor (TCR) V alpha and V beta subfamily-specific sequence in transcripts derived from heart samples obtained from Chagas' cardiomyopathy patients. The average number of TCR V alpha subfamilies (7.1 per tissue sample) was significantly lower than that for TCR V beta subfamilies (15.1 per sample). The average percentage of tissue samples positive per TCR V alpha and V beta subfamily was respectively 39.6% vs. 73.5%. These data suggest that, in Chagas' heart lesions, the detectable TCR V alpha repertoire is significantly narrower than TCR V beta repertoire. On the other hand, in normal heart tissue, diversity of V alpha and V beta TCR is similar among the scarce circulating T cell population. Such evidence of restricted TCR V region repertoire has been described in experimental and human autoimmune diseases. Our results are consistent with the possibility that T cells responsible for heart damage in chronic Chagas' cardiomyopathy may be recognizing a few heart-specific antigenic targets.

The relationship of myocardial high-energy phosphate depletion and lactate accumulation with contractile dysfunctions was investigated in streptozotocin-diabetic (DM) and normal rat hearts. The isolated hearts were perfused with 10(-6) M norepinephrine (NE) at various low-flow rates (0.4-6 ml/min/g heart wt) for 1 h. Left ventricular pressure (LVP) and contractile force (CF) were monitored, through a water-filled balloon in LV and through a hook attached to the apex, respectively. In DM hearts resting CF (diastolic tension) increased, when the perfusion flow rate was reduced below 6 ml and reached a maximum at a flow rate of less than 3 ml. The large increase in LV stiffness correlated with an elevation in diastolic LVP. In normal hearts these parameters were elevated at a flow rate below 1 ml. A flow-dependent decrease in developed CF was more prominent in DM than in normal hearts, while developed LVP and perfusion pressure were slightly higher in DM hearts with a marked increase in the LV stiffness. A flow-dependent decrease in high-energy phosphates and increases in inorganic phosphate and lactate were more prominent in the inner than in the outer layer of LV free wall in both groups. The change of ATP in the inner layer was greater, while increases of lactate in both layers were smaller in DM hearts. Changes in mechanical parameters correlated well with the ATP decrease and lactate increase in the inner layer in both groups. The correlation curves, however, were not coincidental: at the same low ATP and high lactate level, the LV stiffness was higher in DM hearts. Results indicate that DM hearts are more susceptible to flow-reduction with NE and depletion of total ATP in their tissue, and easily suffer from increased LV stiffness. This cannot be explained by the rate of decrease in total ATP and lactate accumulation alone.

The infection developed by Wistar Furth rats inoculated with the Y strain of Trypanosoma cruzi was the experimental model used in our study. The results showed that this infection altered considerably the CD4/CD8 lymphocyte subset ratio and the natural cytotoxic activity of mononuclear cells in the spleen, blood, and myocardial tissue. Concomitantly, an expansion of the number of cells expressing major histocompatibility complex (MHC) class II antigens was observed, as well as spontaneous development of high levels of blast cells, mainly in the spleen. The inflammatory infiltration of the myocardium, made up essentially of CD8+ cells (cytotoxic/suppressor T cells, natural killer cells), was initially found at 9 days postinfection, spread continuously, and was observed until the death of the animals at about 18 days postinfection. T. cruzi infection also enhanced the natural killer activity of mononuclear cells in the blood, spleen, and myocardium. Sorting these cells by affinity columns showed that the natural killer function was performed exclusively by the CD8+ population, which did not express MHC class II antigens. It was shown that the polyclonal T-lymphocyte activation induced by T. cruzi infection results in a wide distribution of CD8+ cells with enhanced natural cytotoxic activity in the spleen, blood, and cardiac tissue.

The case history of a heart transplant patient who died of an acute myocardial infarction 6 months after the procedure is described. The finding of contraction bands and thrombosis associated with endarteritis suggests that coronary vasospasm may have contributed to the acute myocardial infarction during an episode of vascular rejection.

Contractile and energy-metabolic functions were investigated in paced hearts isolated from normal (Normal) and streptozotocin-diabetic rats (DM) during hypoperfusion at 1 ml/min with or without 10(-6) M norepinephrine (NE) and during reperfusion at the pre-hypoperfusion flow. Left ventricular pressure (LVP) and contractile force (CF) were monitored, respectively, through a water-filled balloon in LV and through a hook attached to the apex. A 1-h hypoperfusion without NE caused significant elevations in resting LVP and resting CF only in DM hearts, smaller transmural lactate accumulations in DM hearts, and similar ATP decreases in both groups. Significant decreases in developed LVP and developed CF were observed in both groups. NE during hypoperfusion caused deterioration of these cardiac dysfunctions in both groups, particularly in DM hearts. A 1-h reperfusion caused elevations in resting LVP and resting CF with no recovery in developed CF in Normal hearts, while it caused partial recovery in resting and developed CF in DM hearts. Both groups showed similar partial recovery of ATP. NE during hypoperfusion improved the mechanical dysfunction during reperfusion in DM hearts, but there was a smaller recovery in ATP than in hearts without NE. In vivo insulin treatment in DM restored the cardiac functions to Normal levels. Thus, DM hearts were more vulnerable to hypoperfusion, while Normal hearts were more vulnerable to reperfusion injury.

Extensive and severe myocardial lesions are reported in a patient who died due to snakebite (Crotalus Durissus Terrificus). These lesions are documented by clinical, electrocardiographic, enzymatic and histological evidences. The main pathological features are represented by sarcoplasmatic vacuoles, densely clumped myofibrils and amorphous acidophilic mass into the cardiac fibers. These lesions are identical to those which have already been described in skeletal muscle after snakebite. This seems to be the first case report that shows undoubt myocardial lesions due to snakebite with anatomopathological documentation.

Purpose: To analyse the histological evolution of endomyocardial biopsies from children with active myocarditis, submitted or not to immunosuppressive therapy., Patients and Methods: Four groups of patients were compared, clinically treated as follows: group I--anticongestive drugs (4 patients); group II--prednisone (5 patients); group III--prednisone plus azathioprine (9 patients); group IV--prednisone and cyclosporine (5 patients)., Results: No patient from group I presented any histological improvement during a mean period of 9 months, while evident histological improvement occurred in 25% of patients from group I, 67% from group III and 80% from group IV. The microscopical aspect of resolving myocarditis was only observed in patients from groups III and IV, after treatment., Conclusion: The immunosuppressive therapy with azathioprine or cyclosporine plus prednisone leads to decrease of active myocarditis intensity in a higher proportion of cases than the treatment with only prednisone or no immunosuppressive drugs.

This work is a detailed study of the relevance of three sets of criteria to define myocarditis: Dallas meeting criterion, Edwards criterion and Dallas meeting criterion modified by the authors. Two groups were evaluated: normal autopsied hearts and endomyocardial biopsy from chronic chagasic patients at high risk of having myocarditis. Furthermore, endomyocardial biopsies from patients with dilated cardiomyopathy (DCM) were also evaluated. Applying the Edwards criterion, incidences of myocarditis in normal and chagasic hearts were 0% and 67% while with Dallas meeting criterion they were 0% and 42% and using our criterion the incidences were 0% and 92% respectively. In endomyocardial biopsies from DCM patients, the incidence of myocarditis was 7% with Edwards criterion, 22% with Dallas meeting and 33% with the authors own criterion. The authors concluded that their criterion, which defines myocarditis as the presence of inflammatory mononuclear cells enclosing more than 2 lymphocytes/400X aggregated to the cardiac fiber sarcolemma, is the most appropriate criterion of the three. Myocarditis was found in 33% of the 27 endomyocardial biopsy specimens from patients with DCM.

Effects of nitroglycerin on hemodynamics and transmural distribution of myocardial metabolites were studied at 40% of control coronary perfusion pressure induced by acute coronary stenosis in the canine heart. At 40% of coronary perfusion pressure, high energy phosphate (ATP, creatine phosphate) contents significantly diminished in all layers, especially in the inner layer. A 0.3 micrograms/kg/min intracoronary infusion of nitroglycerin showed no direct effects on energy metabolism in the underperfused myocardium. A 3 micrograms/kg/min i.v. administration of the drug under fixed coronary constriction resulted in decrease in left ventricular peak systolic pressure and systemic blood pressure, and further decrease in coronary perfusion pressure and coronary blood flow. Left ventricular end diastolic pressure and ST-segment of the epicardial ECG were elevated. High-energy phosphate contents further decreased while inorganic phosphate and lactate showed an increase. Under these conditions, release of the constriction sufficient for retention of the coronary perfusion pressure at about 40 mm Hg resulted in significant improvement of the myocardial energy metabolism without a further increase in coronary blood flow. The results suggest that when the myocardium is underperfused due to undilatable stenotic vessels with maximum autoregulation of the regional flow, it may be dangerous to administer nitroglycerin in a dose sufficient to produce a large decrease in coronary perfusion pressure.

Right ventricular endomyocardial biopsy was used to study myocardial involvement in 42 patients with chronic Chagas' disease. Patients were divided into three groups: group A included 16 patients with normal ECGs, normal chest x-rays, and no symptoms; group B included 15 patients with abnormal ECGs and no cardiomegaly; and group C included 11 patients with abnormal ECGs and cardiomegaly. Biopsy fragments were analyzed for hypertrophy, degeneration of myocardial fibers, and interstitial changes such as edema, fibrosis, and inflammatory infiltrate. In group A, 5 of 16 biopsies exhibited none of the previously mentioned alterations. The frequencies pathologic alterations in groups A, B, and C, respectively, were: hypertrophy 31%, 66%, and 100%; degeneration 50%, 86%, and 81%; edema 43%, 46%, and 36%; fibrosis 12%, 33%, and 54%; and inflammatory infiltrate 37%, 66%, and 65%. These data suggest that myocardial lesions of Chagas' disease represent a continuous progression from fiber destruction to substitution by fibrosis, with compensatory hypertrophy; these data also suggest that cardiac dilatation occurs when the extent of fibrosis no longer allows for efficient compensatory hypertrophy.

The influence of coronary perfusion pressure (CPP) on the transmural distribution of myocardial metabolites was examined in the canine heart. Myocardial contents of high energy phosphates and lactate were measured in the inner, middle and outer third of transmural biopsies taken from the underperfused area of the left ventricle; simultaneously epicardial ECG was recorded. Maximum autoregulation of flow was reached when CPP was decreased by approximately 50%; this was indicated by the absence of reactive hyperemia. At this level, high energy phosphate and lactate contents as well as hemodynamic function remained relatively unaltered. At 40% of CPP, coronary flow and the high energy phosphate contents decreased significantly, especially in the subendocardium. At 30% of CPP, there was an accumulation of lactate and a decrease in creatine phosphate content to below one-third of the control in all layers; under these conditions also the ST-segment of the epicardial ECG was elevated. The ST-segment appeared to be relatively insensitive to subendocardial damage; instead, elevation of the ST-segment seemed to be correlated wit the content of lactate in the subepicardium.

The authors analyze the presence of active myocarditis in endomyocardial biopsies from 38 patients with chronic Chagas' disease diagnosed serologically. The patients were divided into three clinical groups of increasing severity. Group I: 13 patients with normal electrocardiograms, normal chest x-rays, and no symptoms; Group II: 13 patients with abnormal electrocardiograms and no cardiomegaly; and Group III: 12 patients with abnormal electrocardiograms, cardiomegaly and heart failure. In order to diagnose myocarditis activity, two sets of criteria were used: one mainly observing histopathologic aspects of inflammatory cells aggressing cardiac fibers; and the other counting the mean number of lymphocytes per high power microscopic field. The results of both methods showed a higher incidence of active myocarditis in the clinical group with heart failure. The present report clearly shows the important role played by activity of myocarditis in the development of heart failure in chronic Chagas' disease. Therefore, the possibility of using drugs to control early stages of the activity of the inflammatory process is suggested. On the other hand, endomyocardial biopsy (EMB) seems to be an adequate method to evaluate the intensity of the cardiac inflammatory process in Chagas' heart disease.

The first case of a hyperacute rejection of a human cardiac allograft in Brazil is reported. The histopathological aspects of hyperacute cardiac rejection in its earlier moments are described when degenerative and necrotic features of the cardiac fibers are not totally developed. The authors believe that neutrophilic exudation and lesion of the vessel wall are good signs for a correct diagnosis of hyperacute rejection. Furthermore, they observed that the process is diffuse enough to justify the indication of endomyocardial biopsy when there are reasons to suspect this diagnosis. Presence of IgM and complement (C3) are also useful.

The effects of propranolol treatment on adrenoceptor reactivity and on cardiac myosin ATPase activity have been studied. Eight mongrel dogs weighing 8 to 14 Kg were given propranolol orally 3 times daily (10 mg/Kg/day) for 2 weeks. Although the levels of propranolol were effective and there was a significant decrease in resting heart rate, there was no evidence of a rebound adrenoceptor hypersensitivity after abrupt withdrawal of propranolol treatment. The responsiveness of cardiovascular systems to 1-isoproterenol (1-ISO) was significantly attenuated 15 hrs after the last medication, but it did not differ from the premedication levels 6 days after discontinuation of medication. The effects of 1-ISO on adenylate cyclase activity in the myocardial membrane preparations were not significantly different between the 3 groups (no medication, 1 day and 6 days after discontinuation). With propranolol treatment, though a rise in total plasma catecholamine (norepinephrine, epinephrine, dopamine) levels was the predominant change, there were no definite changes in respective catecholamines. Serum triiodothyronine (T3) increased during medication in 7 of the 8 animals and decreased after medication. Calcium-activated and K+-activated myosin ATPase activity in the inner and outer layers of the left ventricular wall were uniform in unmedicated dogs, and propranolol produced no significant effects. No reliable evidence for propranolol withdrawal syndromes was provided in the present study.

1. Fragments of dog hearts submitted to 1, 6, 10, 24 and 48 h of autolysis at 20 degrees C were studied with freeze-fracture and thin-section techniques under the transmission electron microscope. 2. The freeze-fracture replicas revealed maximal reduction in the mean number and clustering of intramembrane particles at 6 h post mortem, indicating irreversible cellular damage. However, signs of lethal damage (intramitochondrial amorphous dense bodies) were not observed in thin sections of the same material. 3. The present study indicates that signs of irreversible damage similar to that occurring in in vivo ischemic alterations can be detected earlier by the freeze-fracture technique than by the thin-section technique.

The effect of verapamil on the isoproterenol (ISO)-induced transmural metabolic lesion in the left ventricular wall was investigated in the rat heart. The treatment with ISO 2.5 mg/Kg s.c. on 2 consecutive days resulted in significant decreases of creatine phosphate in the subendocardium (ENDO) and of adenosine triphosphate in the ENDO and the subepicardium. On the other hand, inorganic phosphate (Pi) and lactate (LA) were increased in both layers. These changes were more prominent in the ENDO. Pretreatment with verapamil 25 mg/Kg s.c. prevented the reduction of high energy phosphate compounds and the increases of Pi and LA in both layers by ISO.

Effects of a new beta-adrenergic blocking agent, 5-(3-tert-butylamino-2-hydroxy) propoxy-3,4-dihydrocarbostyril hydrochloride (OPC-1085), on the coronary circulation and myocardial metabolism were investigated in anesthetized open-chest dogs and isolated perfused dog hearts. In anesthetized open-chest dogs, OPC-1085 antagonized the responses to isoproterenol of heart rate, Vmax, mean blood pressure, myocardial oxygen consumption, coronary blood flow and redox potential. The antagonistic potency of OPC-1085 was stronger than propranolol. OPC-1085 3 to 30 mug/kg caused appreciable decreases, but in doses of 100 to 1,000 mug/kg caused increases in heart rate and Vmax. The effect of OPC-1085 on max dp/dt was similar to that on Vmax. However, propranolol 3 to 3,000 mu-g/kg caused only decreases in heart rate, Vmax and max dp/dt. OPC-1085 3,10 mu-g/kg while propranolol 30, 100 mu-g/kg caused a fall in myocardial oxygen consumption and coronary blood flow. In isolated perfused hearts, intracoronary injection of OPC-1085 0.1 mg almost completely suppressed isoproterenol-induced augmentation of heart rate, myocardial contractile force and coronary blood flow and reduction of redox potential. OPC-1085 0.1 mg caused slight increases in heart rate, myocardial contractile force and myocardial oxygen consumption. It is concluded that OPC-1085 is a more potent beta-adrenergic blocking agent than propranolol and possesses a weak negative inotropic effect in doses of 3 to 30 mu-g/kg and a intrinsic sympathomimetic activity in doses of 100 to 1,000 mu-g/kg.

1. In a homologous radioimmunoassay for canine ventricular myosin light chains, the following percentages of cross-reactivities were obtained using the dog as a reference: human, 28%; sheep, 21%; cat, 8%; guinea-pig, 7%; rabbit, 5%; and rat, 4%. 2. In a homologous double diffusion immunoassay using specific gamma G to canine cardiac myosin heavy chains, dog cardiac myosin showed immunological identity with human and sheep cardiac myosin but partial identity with myosins of other species. 3. On a 5-20% polyacrylamide gradient, light chain C1 was electrophoretically distinct in some species; light chain C2 was electrophoretically identical in all species. 4. The K+-activated myosin ATPase of small animals was higher than that of larger animals at an alkaline pH; the same was true for Ca2+-activated myosin when assayed at pH 6.3.

The participation of coronary perfusion pressure in hemodynamic and transmural metabolic changes was examined in the open chest canine heart. At lower pressure than 50% of the control, reactive hyperemia disappeared and the coronary arterial inflow precipitously decreased. In 8 dogs, when the coronary arterial inflow was decreased to 47-49% of the control by coronary constriction for 15 min, the coronary perfusion pressure fell in various degrees ranging from 39 to 73% of the control. At a lower pressure than 60% of the control, creatine phosphate (CP) content and its ratio of subendocardium (ENDO) to subepicardium (EPI) decreased, while lactate (LA) content and its ratio of ENDO to EPI increased depending on the degree of the fall in coronary perfusion pressure. A little decrease in ATP content was produced only in the subendocardium under the lower pressure than 50% of the control. When the CP content decreased to below one-third of the control, the significant accumulation of lactate and the precipitous decrease in ATP occurred. Our results suggest that the coronary perfusion pressure has an important role for a severity of the transmural energy metabolism in the hypoperfused ventricle.

Specific activities of enzymes in bovine hearts were measured. The enzyme activity ratios between the conduction system and the myocardium were 1.9 for G-6-PDH, 1.2 for PFK, 0.5 for total phosphorylase and LDH, 0.4 for GOT and MDH, 0.3 for SDH, 0.2 for Aldolase and CPK, and 0.1 for alpha GPDH. Approximate values for relative volume of Purkinje cells, nerve fibers and connective tissues in the conduction system were 30%, 8%, and 62%, respectively. It is concluded that activities of enzymes serving for anaerobic glycolysis in Purkinje cells are almost the same or slightly higher than those in the myocardium, and activity of enzyme for pentose shunt in the conductive tissue is higher than that in the myocardium.

The effects of equipotent doses in negative inotropic and chronotropic properties of nipradilol [10 micrograms/kg/min intravenously (i.v.)] and propranolol (20 micrograms/kg/min i.v.) on hemodynamics and transmural energy metabolites in ischemic hearts were examined in anesthetized dogs. After 5-min infusion of these agents, coronary perfusion pressure of 30 mm Hg was induced by acute coronary stenosis for 10 min. Coronary blood inflow and myocardial contractile force (MCF) in the control ischemic area decreased to about one-third and two-thirds of the respective starting levels. In the nipradilol group, similar changes were observed, but in the propranolol group the MCF tended to decrease further. Cardiac effort index decreased to about two-thirds in both groups. The left ventricular end-diastolic pressure (LVEDP) increased by 4.3 mm Hg with saline, by 8.8 mm Hg with propranolol, and by 1.3 mm Hg with nipradilol. ATP depletion in the ischemic myocardium (by 29 and 22% in inner and outer layers, respectively) was restored to normal level by either agent. A decrease in creatine phosphate and an accumulation of lactate were significantly alleviated by nipradilol (by 74 and 59----by 39 and 21%, and by 4.9 and 2.3----by 0.7 and 0.2 times, respectively), but not by propranolol. The results indicate that in addition to a decrease in myocardial oxygen consumption caused by the beta-adrenoceptor blocking effects of nipradilol, reductions in preload and afterload caused by the vasodilating property significantly contribute to nipradilol-induced improvement in the ischemic derangement of transmural energy metabolism.

Endomyocardial biopsy seems to be the most accurate method to use for diagnosis and follow-up of acute rejection of the transplanted heart. This investigation compared a noninvasive procedure, gallium-67 imaging, with endomyocardial biopsy in the detection of acute rejection in heart transplantation. Seven male patients (aged 41 to 54 years) sequentially had 46 gallium-67 scintigrams and 46 endomyocardial biopsies between 1 week and 8 months after transplantation. Both studies were obtained in the same day, 48 hours after the administration of an intravenous injection of gallium-67 citrate. Cardiac uptake was graded as negative, mild, moderate, and marked according to an increasing count ratio with rib and sternal uptakes. Histologic findings were graded as negative, mild acute rejection, moderate acute rejection, severe acute rejection, resolving rejection, and nonspecific reaction. Negative biopsies were not found with moderate uptake, and neither moderate nor severe acute rejection were found with negative scintigrams. Imaging sensitivity was 83% with 17% false negatives and 9% false positives. Of seven studies with moderate uptake, five showed moderate acute rejection, and the patients had specific therapy with a decline in uptake, which correlated with resolving rejection. It is conceivable that in the future this technique may be used as a screening procedure for sequential endomyocardial biopsies in the follow-up of heart transplant patients.

Effects of nifedipine treatment on cardiac myosin ATPase activity and responsiveness of cardiovascular system to catecholamine have been studied. Eight mongrel dogs weighing 7.5 to 13.5 kg were given nifedipine orally twice daily (60 mg/day) for 2 weeks. Ten minutes after the first administration of nifedipine (30 mg p.o.) the heart rate increased significantly and it lasted for, at least, 4 hours. Two-week treatment of nifedipine caused a decrease of the resting heart rate, but the maximal heart rate increase by nifedipine administration was almost the same as the one on the first day. The effects of norepinephrine on heart rate and blood pressure, responsiveness of isolated coronary arteries to some agents inducing a contraction and, Ca2+-activated and K+-activated cardiac myosin ATPase activities were not significantly different between control and nifedipine treatment groups.

We have studied the effects of reoxygenation on hypoxia-induced changes in contents of high energy phosphate compounds in pacemaker cells of nodal tissues excised from the rabbit heart, and effects of coenzyme Q10 on the electrical activity and metabolite contents in the tissue exposed to hypoxia and then reoxygenated. The contents of ATP and creatine phosphate (CP) in the sinoatrial node tissue were markedly reduced within 15-30 min after exposure to hypoxic Tyrode's solution. Reoxygenation produced almost complete recovery of the tissue ATP, but not of CP. After 60-120 min of hypoxia, the tissue ATP and CP decreased to about 60-30% of the initial value, but were not recovered by reoxygenation. Coenzyme Q10 (CoQ) at concentrations of 10(-6)-10(-5) g/ml did not produce changes in action potential parameters in the normal Tyrode's solution. CoQ (10(-5) g/ml) did not prevent the decreases in tissular ATP and CP in the initial period of hypoxia (30-60 min), but the ATP content at 120 min of hypoxia in the presence of CoQ was higher than the control. CoQ promoted recovery of tissular ATP after reoxygenation. Our results provide direct evidence that generation of action potentials in the sinoatrial nodal cells can be maintained by a small amount of ATP produced by the anaerobic glycolytic pathway. The present results suggest that exogenous CoQ would facilitate resynthesis of ATP in the functionally impaired mitochondria.

The authors describe the clinical-pathologic findings in four patients with myocardial infarct (MI) associated with Chagas' disease, found among 181 autopsies of chronic congestive cardiac chagasic patients. Organized thrombo-embolus was found in the epicardial portion of a coronary artery in one instance and thrombosis in the apex of the left ventricle as well as systemic infarcts were found in all cases. These data suggest thrombo-embolism, probably from the apex of the left ventricle, as a possible cause for the regional (large; transmural) MI in chronic Chagas' heart disease. The mechanism usually operative in MI, i.e. complicated atherosclerosis, was not present in the patients of this series. Moreover, our data do not support either small artery disease or heart denervation as etiologic factors for regional MI.