Modeling pulmonary fibrosis by abnormal expression of telomerase/apoptosis/collagen V in experimental usual interstitial pneumonia

Limitations on tissue proliferation capacity determined by telomerase/apoptosis balance have been implicated in pathogenesis of idiopathic pulmonary fibrosis. In addition, collagen V shows promise as an inductor of apoptosis. We evaluated the quantitative relationship between the telomerase/apoptosis index, collagen V synthesis, and epithelial/fibroblast replication in mice exposed to butylated hydroxytoluene (BHT) at high oxygen concentration. Two groups of mice were analyzed: 20 mice received BHT, and 10 control mice received corn oil. Telomerase expression, apoptosis, collagen I, III, and V fibers, and hydroxyproline were evaluated by immunohistochemistry, in situ detection of apoptosis, electron microscopy, immunofluorescence, and histomorphometry. Electron microscopy confirmed the presence of increased alveolar epithelial cells type 1 (AEC1) in apoptosis. Immunostaining showed increased nuclear expression of telomerase in AEC type 2 (AEC2) between normal and chronic scarring areas of usual interstitial pneumonia (UIP). Control lungs and normal areas from UIP lungs showed weak green birefringence of type I and III collagens in the alveolar wall and type V collagen in the basement membrane of alveolar capillaries. The increase in collagen V was greater than collagens I and III in scarring areas of UIP. A significant direct association was found between collagen V and AEC2 apoptosis. We concluded that telomerase, collagen V fiber density, and apoptosis evaluation in experimental UIP offers the potential to control reepithelization of alveolar septa and fibroblast proliferation. Strategies aimed at preventing high rates of collagen V synthesis, or local responses to high rates of cell apoptosis, may have a significant impact in pulmonary fibrosis.

Interstitial pneumonitis in canine visceral leishmaniasis

Forty-one naturally infected dogs with visceral leishmaniasis from an urban area of Corumbá (Mato Grosso do Sul-BRAZIL) were studied and three types of lung involvement due to visceral leishmaniasis were characterized; a cellular, a cellular-fibrotic and a fibrotic type. These types seem to represent a sequential evolutive proce'as. Visceral leishmaniasis frequently causes an interstitial pneu monitis in naturally infected dogs (80.5%) as well as in man and experimentally infected hamsters.

Chronic interstitial pneumonitis in dogs naturally infected with Leishmania (Leishmania) chagasi: a histopathological and morphometric study

Eighteen mongrel dogs of unknown age and naturally infected with Leishmania (Leishmania) chagasi, were obtained from the City Hall of Belo Horizonte, Brazil. Four dogs were used as control. Lung samples were obtained and immediately fixed in formalin. The histopathological picture of all lung tissue sections was a chronic and diffuse interstitial pneumonitis. The thickened inter-alveolar septa were characterized by the cellular exudate (mostly macrophages, lymphocytes and plasmocytes) associated with collagen deposition. Morphometric analysis showed greater septal thickness in the infected animals than in controls. In fact, the morphometric study of collagen stained with ammoniac silver confirmed a larger deposition of collagen in the infected animals. The parasitologic method was carried out during the study of the lesions on the slides. However, we did not observe any correlation between the histopathologic and morphometric data and the clinical status of the animals. We conclude that the pulmonary lesions observed in all naturally infected dogs were correlated with the disease and that the morphometric method used was satisfactory for the analysis of septal thickness and of increased collagen deposition, confirming the presence of fibrosis.

Potential utility of hyperbaric oxygen therapy and propolis in enhancing the leishmanicidal activity of glucantime

In this study we investigated the efficacy of hyperbaric oxygen (HBO) therapy, alone or combined with the pentavalent antimonial glucantime on Leishmania amazonensis infection. In parallel, the effect of Brazilian red propolis gel (propain) alone or combined with glucantime on L. amazonensis infection was evaluated. The inhibition of the infection in macrophages treated with glucantime in combination with HBO exposition was greater than that of macrophages treated with glucantime alone or HBO alone. The susceptible mouse strain BALB/c infected in the shaved rump with L. amazonensis treated with glucantime and exposed to HBO showed: time points in the course of the disease in which lesions were smaller than those of mice treated with glucantime alone and revascularization of the skin in the lesion site; interferon-gamma (IFN-g) levels were not elevated in lymph node cells from these animals. Propain alone was not efficient against lesions, although less exudative lesions were observed in animals treated with propain alone or combined with glucantime. These results reveal the potential value of HBO and red propolis in combination with glucantime for treating cutaneous leishmaniasis and encourage further studies on the effect of more aggressive HBO, propolis and glucantime therapies on different mouse models of leishmaniasis.

Effect of hyperbaric oxygen on the regeneration of experimental crush injuries of nerves

Hyperbaric oxygen has been successfully used on treatment of acute ischemic injuries involving soft tissues and chronic injuries. In nerve crush injuries, the mechanisms involved are very similar to those found in ischemic injuries. Consequently, it is logical to hypothesize that hyperbaric oxygen should improve nerve repair, which is a critical step on functional recovery. In the present study, we created standard nerve crush injuries on sciatic nerves of rats, which underwent treatment with hyperbaric oxygen. Results were assessed by functional evaluation using walking-track analysis. The functional recovery indexes observed did not differ from control group. We concluded that hyperbaric oxygen therapy, in the schedule used, had no influence on functional recovery after nerve crush injuries.

Assessment of functional capacity through oxygen consumption in patients with asymptomatic probable heart disease

PURPOSE: To compare peak exercise oxygen consumption (VO2peak) of healthy individuals with asymptomatic individuals with probable heart disease. METHODS: Ninety-eight men were evaluated. They were divided into two groups: 1) 39 healthy individuals (group N) with an age range of 50±4.6 years; and 2) 59 asymptomatic individuals with signs of atherosclerotic and/or hypertensive heart disease (group C) with an age range of 51.9±10.4 years. In regard to age, height, body surface area, percentage of fat, lean body mass, and daily physical activity, both groups were statistically similar. Environmental conditions during the ergometric test were also controlled. RESULTS: Maximal aerobic power (watts), VO2peak, maximal heart rate, and maximal pulmonary ventilation were lower in group C (p<0.01) than in group N; weight, however, was lower in group N (p=0.031) than in group C. Differences in the respiratory gas exchange index, heart rate at rest, and the maximal double product of the two groups were not statistically significant. CONCLUSION: Signs of probable heart disease, even though asymptomatic, may reduce the functional capacity, perhaps due to the lower maximal cardiac output and/or muscle metabolic changes.

Oxygen therapy, continuous positive airway pressure, or noninvasive bilevel positive pressure ventilation in the treatment of acute cardiogenic pulmonary edema

OBJECTIVE: To compare the effects of 3 types of noninvasive respiratory support systems in the treatment of acute pulmonary edema: oxygen therapy (O2), continuous positive airway pressure, and bilevel positive pressure ventilation. METHODS: We studied prospectively 26 patients with acute pulmonary edema, who were randomized into 1 of 3 types of respiratory support groups. Age was 69±7 years. Ten patients were treated with oxygen, 9 with continuous positive airway pressure, and 7 with noninvasive bilevel positive pressure ventilation. All patients received medicamentous therapy according to the Advanced Cardiac Life Support protocol. Our primary aim was to assess the need for orotracheal intubation. We also assessed the following: heart and respiration rates, blood pressure, PaO2, PaCO2, and pH at begining, and at 10 and 60 minutes after starting the protocol. RESULTS: At 10 minutes, the patients in the bilevel positive pressure ventilation group had the highest PaO2 and the lowest respiration rates; the patients in the O2 group had the highest PaCO2 and the lowest pH (p<0.05). Four patients in the O2 group, 3 patients in the continuous positive pressure group, and none in the bilevel positive pressure ventilation group were intubated (p<0.05). CONCLUSION: Noninvasive bilevel positive pressure ventilation was effective in the treatment of acute cardiogenic pulmonary edema, accelerated the recovery of vital signs and blood gas data, and avoided intubation.

An Equation for the Prediction of Oxygen Consumption in a Brazilian Population

Background: The equations predicting maximal oxygen uptake (VO2max or peak) presently in use in cardiopulmonary exercise testing (CPET) softwares in Brazil have not been adequately validated. These equations are very important for the diagnostic capacity of this method. Objective: Build and validate a Brazilian Equation (BE) for prediction of VO2peak in comparison to the equation cited by Jones (JE) and the Wasserman algorithm (WA). Methods: Treadmill evaluation was performed on 3119 individuals with CPET (breath by breath). The construction group (CG) of the equation consisted of 2495 healthy participants. The other 624 individuals were allocated to the external validation group (EVG). At the BE (derived from a multivariate regression model), age, gender, body mass index (BMI) and physical activity level were considered. The same equation was also tested in the EVG. Dispersion graphs and Bland-Altman analyses were built. Results: In the CG, the mean age was 42.6 years, 51.5% were male, the average BMI was 27.2, and the physical activity distribution level was: 51.3% sedentary, 44.4% active and 4.3% athletes. An optimal correlation between the BE and the CPET measured VO2peak was observed (0.807). On the other hand, difference came up between the average VO2peak expected by the JE and WA and the CPET measured VO2peak, as well as the one gotten from the BE (p = 0.001). Conclusion: BE presents VO2peak values close to those directly measured by CPET, while Jones and Wasserman differ significantly from the real VO2peak.

Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry

AbstractBackground:Aerobic fitness, assessed by measuring VO2max in maximum cardiopulmonary exercise testing (CPX) or by estimating VO2max through the use of equations in exercise testing, is a predictor of mortality. However, the error resulting from this estimate in a given individual can be high, affecting clinical decisions.Objective:To determine the error of estimate of VO2max in cycle ergometry in a population attending clinical exercise testing laboratories, and to propose sex-specific equations to minimize that error.Methods:This study assessed 1715 adults (18 to 91 years, 68% men) undertaking maximum CPX in a lower limbs cycle ergometer (LLCE) with ramp protocol. The percentage error (E%) between measured VO2max and that estimated from the modified ACSM equation (Lang et al. MSSE, 1992) was calculated. Then, estimation equations were developed: 1) for all the population tested (C-GENERAL); and 2) separately by sex (C-MEN and C-WOMEN).Results:Measured VO2max was higher in men than in WOMEN: -29.4 ± 10.5 and 24.2 ± 9.2 mL.(kg.min)-1 (p < 0.01). The equations for estimating VO2max [in mL.(kg.min)-1] were: C-GENERAL = [final workload (W)/body weight (kg)] x 10.483 + 7; C-MEN = [final workload (W)/body weight (kg)] x 10.791 + 7; and C-WOMEN = [final workload (W)/body weight (kg)] x 9.820 + 7. The E% for MEN was: -3.4 ± 13.4% (modified ACSM); 1.2 ± 13.2% (C-GENERAL); and -0.9 ± 13.4% (C-MEN) (p < 0.01). For WOMEN: -14.7 ± 17.4% (modified ACSM); -6.3 ± 16.5% (C-GENERAL); and -1.7 ± 16.2% (C-WOMEN) (p < 0.01).Conclusion:The error of estimate of VO2max by use of sex-specific equations was reduced, but not eliminated, in exercise tests on LLCE.

Reduction in Post-Marathon Peak Oxygen Consumption: Sign of Cardiac Fatigue in Amateur Runners?

Abstract Background: Prolonged aerobic exercise, such as running a marathon, produces supraphysiological stress that can affect the athlete's homeostasis. Some degree of transient myocardial dysfunction ("cardiac fatigue") can be observed for several days after the race. Objective: To verify if there are changes in the cardiopulmonary capacity, and cardiac inotropy and lusitropy in amateur marathoners after running a marathon. Methods: The sample comprised 6 male amateur runners. All of them underwent cardiopulmonary exercise testing (CPET) one week before the São Paulo Marathon, and 3 to 4 days after that race. They underwent echocardiography 24 hours prior to and immediately after the marathon. All subjects were instructed not to exercise, to maintain their regular diet, ingest the same usual amount of liquids, and rest at least 8 hours a day in the period preceding the CPET. Results: The athletes completed the marathon in 221.5 (207; 250) minutes. In the post-marathon CPET, there was a significant reduction in peak oxygen consumption and peak oxygen pulse compared to the results obtained before the race (50.75 and 46.35 mL.kg-1 .min-1; 19.4 and 18.1 mL.btm, respectively). The echocardiography showed a significant reduction in the s' wave (inotropic marker), but no significant change in the E/e' ratio (lusitropic marker). Conclusions: In amateur runners, the marathon seems to promote changes in the cardiopulmonary capacity identified within 4 days after the race, with a reduction in the cardiac contractility. Such changes suggest that some degree of "cardiac fatigue" can occur.

Chronic murine myocarditis due to Trypanosoma cruzi: an ultrastructural study and immunochemical characterization of cardiac interstitial matrix

In an attempt to define the mouse-model for chronic Chagas' disease, a serological, histopathological and ultrastructural study as well as immunotyping of myocardium collagenic matrix were performed on Swiss mice, chronically infected with Trypanosoma cruzi strains: 21 SF and mambaí (Type II); PMN and Bolivia (Type III), spontaneously surviving after 154 to 468 days of infection. Haemagglutination and indirect immunofluorescence tests showed high titres of specific antibodies. The ultrastructural study disclosed the cellular constitution of the inflammatory infiltrate showing the predominance of monocytes, macrophages with intense phagocytic activity, fibroblasts, myofibroblasts and abundant collagen matrix suggesting the association of the inflammatory process with fibrogenesis in chronic chagasic cardiomyopathy. Artertolar and blood capillary alterations together with dissociation of cardiac cells from the capillary wall by edema and inflammation were related to ultrastructural lesions of myocardial cells. Rupture of parasitized cardiac myocells contribute to intensify the inflammatory process in focal areas. Collagen immunotyping showed the predominance of Types III and IV collagen. Collagen degradation and phagocytosis were present suggesting a reversibility of the fibrous process. The mouse model seems to be valuable in the study of the pathogenetic mechanisms in Chagas cardiomyopathy, providing that T. cruzi strains of low virulence and high pathogenecity are used.

Reactive Nitrogen and Oxygen Intermediates in Patients with Cutaneous Leishmaniasis

The metabolisms of reactive nitrogen and oxygen intermediates (RNI and ROI) in patients with cutaneous leishmaniasis (CL) were investigated and compared with those of healthy subjects. To determine RNI metabolism, nitrite plus nitrate concentrations were measured spectrophotometrically. Nitrite concentration in plasma was determined directly by the Griess method. Nitrate levels in plasma were measured after reduction into nitrite by using copper-cadmium-zinc. ROI metabolism was evaluated by measuring erythrocyte superoxide dismutase, catalase and glutathione peroxidase activities. Plasma nitrite plus nitrate levels and erythrocyte superoxide dismutase activity were higher in the patient group than healthy subjects (p<0.01). In contrast, erythrocyte catalase and glutathione peroxidase activities were lower (p<0.05, p<0.01, respectively). ROI metabolism was altered in relation to hydrogen peroxide elevation in patients with CL. These alterations in ROI enable nitric oxide (NO) to amplify its leishmanicidal effect. The determination of ROI and RNI in patients with CL may be a useful tool to evaluate effector mechanisms of NO and clinical manifestations.

Trypanosoma cruzi: parasite antigens sequestered in heart interstitial dendritic cells are related to persisting myocarditis in benznidazole-treated mice

We investigated whether sequestered Trypanosoma cruzi antigens found in heart interstitial dendritic cells (IDCs) contribute to the residual myocarditis found in mice following treatment with benznidazole, a specific chemotherapeutic drug. IDCs are antigen-presenting cells that are MHC-II-receptor dependent. Swiss mice were divided into two experimental groups: the 1st group was infected with the Colombian strain of T. cruzi, which is resistant to treatment with benznidazole, and the 2nd group was infected with clone 21SF-C 3, which has a medium susceptibility to the drug. Treatment of the Colombian strain group started on the 120th day post-infection and for the 21SF-C3 strain group treatment was started on the 90th day. In both groups, treatment lasted for 90 days. The animals were sacrificed either 150 or 200 days post-treatment. The myocardium was analysed by immunohistochemistry using anti-MAC3, 33D1, CD11b and CD11c monoclonal antibodies for IDCs or anti-T. cruzi purified antibodies. Parasite antigens were expressed on the IDC membranes in both treated and untreated mice. Myocarditis subsided following treatment, evidenced by both histological and morphometrical evaluation. A reduction in the number of IDCs carrying T. cruzi antigens in the treated group indicates that the elimination of parasites influences antigen presentation with concomitant decreases in inflammation. There is a correlation between the presence of T. cruzi antigens in these cells and the chronic focal, residual myocarditis seen in treated mice.