Miriam Lemos

Distribution of Collagen in the Lamina Propria of the Human Vocal Fold

Objectives To describe the arrangement of collagen fibers in the lamina propria of the human vocal fold.

Endothelial dysfunction in the pulmonary artery induced by concentrated fine particulate matter exposure is associated with local but not systemic inflammation

Clinical evidence has identified the pulmonary circulation as an important target of air pollution. It was previously demonstrated that in vitro exposure to fine particulate matter (aerodynamic diameter≤2.5 μm, PM2.5) induces endothelial dysfunction in isolated pulmonary arteries. We aimed to investigate the effects of in vivo exposure to urban concentrated PM2.5 on rat pulmonary artery reactivity and the mechanisms involved. For this, adult Wistar rats were exposed to 2 weeks of concentrated São Paulo city air PM2.5 at an accumulated daily dose of approximately 600 μg/m3. Pulmonary arteries isolated from PM2.5-exposed animals exhibited impaired endothelium-dependent relaxation to acetylcholine without significant changes in nitric oxide donor response compared to control rats. PM2.5 caused vascular oxidative stress and enhanced protein expression of Cu/Zn- and Mn-superoxide dismutase in the pulmonary artery. Protein expression of endothelial nitric oxide synthase (eNOS) was reduced, while tumor necrosis factor (TNF)-α was enhanced by PM2.5 inhalation in pulmonary artery. There was a significant positive correlation between eNOS expression and maximal relaxation response (Emax) to acetylcholine. A negative correlation was found between vascular TNF-α expression and Emax to acetylcholine. Plasma cytokine levels, blood cells count and coagulation parameters were similar between control and PM2.5-exposed rats. The present findings showed that in vivo daily exposure to concentrated urban PM2.5 could decrease endothelium-dependent relaxation and eNOS expression on pulmonary arteries associated with local high TNF-α level but not systemic pro-inflammatory factors. Taken together, the present results elucidate the mechanisms underlying the trigger of cardiopulmonary diseases induced by urban ambient levels of PM2.5.

Homozygous deletion of p16INK4A and tobacco carcinogen exposure in nonsmall cell lung cancer

Inactivation of p16INK4a in the Rb pathway is among the most common somatic alterations observed in nonsmall cell lung cancers (NSCLCs). While epigenetic inactivation of the p16INK4a gene promoter has been shown to be associated with increased tobacco carcinogen exposure, little investigation of any similar association of homozygous deletion or mutation of p16INK4a and tobacco use has been completed. In 177 consecutive NSCLCs, we examined the determinants of p16INK4a homozygous deletion and mutation, including the pattern of tobacco smoking and asbestos exposure. We observed that p16INK4a homozygous deletion occurred at a higher frequency in never smokers as compared to former and current smokers (p = 0.01). This observation suggested that tumors from these patients might be more prone to DNA deletion events; consistent with this, epigenetic silencing of the DNA double‐strand break repair genes FancF and BRCA1 was also associated with homozygous deletion of p16INK4a(p = 0.002 and p = 0.06, respectively). Finally, mutation of p16INK4a was rare and only occurred in patients who were smokers. Hence, the character of somatic alteration in the Rb pathway (deletion, mutation or methylation silencing) in NSCLC is associated with the pattern of tobacco exposure, suggesting that susceptibility to lung cancer is, at least in part, mediated by the biological mechanism that selects for the character of the induced somatic lesion.

Organization of collagen and elastic fibers studied in stretch preparations of whole mounts of human visceral pleura

Fibers of the collagenous and elastic systems are most relevant in the double mechanical action of visceral pleura (VP), i.e. volume limitation and the generation of elastic recoil pressure. In this work we studied the organization of these fibrous components of VP in two situations: normal lungs and bullous disease. We employed histochemical methods on conventional histological slides and on thin spreads of whole mounts of visceral pleura. In addition, the scanning electron microscope was also used. According to our results, pleural function is made possible by the combination of both the elastic and collagenous fiber systems, each one having as intrinsic organizational pattern. Marked alterations of pleural bullous structure are observed with changes in lung volume. Fibers of the elastic and collagenous systems are clearly interdependent elements. Collagenous fibers are interwoven in a plaited structure that closely resembles the osiers of a wicker basket, indicating that collagen fibers allow for lung volume increase up to a point of maximal stretching of the system. The pleural contribution to lung elastic recoil pressure originates from the elastic network which turns back to its resting position when inspiratory pressures are negligible. The pleural immobility in bullous disease is associated with an almost complete absence of elastic fibers and the presence of very thick collagen fibers, suggestive of a cicatricial process, devoid of any characteristic pattern of distribution.

Cardiac and pulmonary oxidative stress in rats exposed to realistic emissions of source aerosols.

In vivo chemiluminescence (CL) is a measure of reactive oxygen species in tissues. CL was used to assess pulmonary and cardiac responses to inhaled aerosols derived from aged emissions of three coal-fired power plants in the USA. Sprague–Dawley rats were exposed to either filtered air or: (1) primary emissions (P); (2) ozone oxidized emissions (PO); (3) oxidized emissions + secondary organic aerosol (SOA) (POS); (4) neutralized oxidized emissions + SOA (PONS); and (5) control scenarios: oxidized emissions + SOA in the absence of primary particles (OS), oxidized emissions alone (O), and SOA alone (S). Immediately after 6 hours of exposure, CL in the lung and heart was measured. Tissues were also assayed for thiobarbituric acid reactive substances (TBARS). Exposure to P or PO aerosols led to no changes compared to filtered air in lung or heart CL at any individual plant or when all data were combined. POS caused significant increases in lung CL and TBARS at only one plant, and not in combined data from all plants; PONS resulted in increased lung CL only when data from all plants were combined. Heart CL was also significantly increased with exposure to POS only when data from all plants were combined. PONS increased heart CL significantly in one plant with TBARS accumulation, but not in combined data. Exposure to O, OS, and S had no CL effects. Univariate analyses of individual measured components of the exposure atmospheres did not identify any component associated with increased CL. These data suggest that coal-fired power plant emissions combined with other atmospheric constituents produce limited pulmonary and cardiac oxidative stress.

Toxicological evaluation of realistic emission source aerosols (TERESA)--power plant studies: assessment of breathing pattern.

Our approach to study multi-pollutant aerosols isolates a single emissions source, evaluates the toxicity of primary and secondary particles derived from this source, and simulates chemical reactions that occur in the atmosphere after emission. Three U.S. coal-fired power plants utilizing different coals and with different emission controls were evaluated. Secondary organic aerosol (SOA) derived from α-pinene and/or ammonia was added in some experiments. Male Sprague-Dawley rats were exposed for 6 h to filtered air or different atmospheric mixtures. Scenarios studied at each plant included the following: primary particles (P); secondary (oxidized) particles (PO); oxidized particles + SOA (POS); and oxidized and neutralized particles + SOA (PONS); additional control scenarios were also studied. Continuous respiratory data were obtained during exposures using whole body plethysmography chambers. Of the 12 respiratory outcomes assessed, each had statistically significant changes at some plant and with some of the 4 scenarios. The most robust outcomes were found with exposure to the PO scenario (increased respiratory frequency with decreases in inspiratory and expiratory time); and the PONS scenario (decreased peak expiratory flow and expiratory flow at 50%). PONS findings were most strongly associated with ammonium, neutralized sulfate, and elemental carbon (EC) in univariate analyses, but only with EC in multivariate analyses. Control scenario O (oxidized without primary particles) had similar changes to PO. Adjusted R2 analyses showed that scenario was a better predictor of respiratory responses than individual components, suggesting that the complex atmospheric mixture was responsible for respiratory effects.

Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA)-power plant studies: assessment of cellular responses

The Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA) project assessed primary and secondary particulate by simulating the chemical reactions that a plume from a source might undergo during atmospheric transport and added other atmospheric constituents that might interact with it. Three coal-fired power plants with different coal and different emission controls were used. Male Sprague-Dawley rats were exposed for 6 h to either filtered air or aged aerosol from the power plant. Four exposure scenarios were studied: primary particles (P); primary + secondary (oxidized) particles (PO); primary + secondary (oxidized) particles + SOA (POS); and primary + secondary (oxidized) particles neutralized + SOA (PONS). Exposure concentrations varied by scenario to a maximum concentration of 257.1 ± 10.0 μg/m3. Twenty-four hours after exposure, pulmonary cellular responses were assessed by bronchoalveolar lavage (BAL), complete blood count (CBC), and histopathology. Exposure to the PONS and POS scenarios produced significant increases in BAL total cells and macrophage numbers at two plants. The PONS and P scenarios were associated with significant increases in BAL neutrophils and the presence of occasional neutrophils and increased macrophages in the airways and alveoli of exposed animals. Univariate analyses and random forest analyses showed that increases in total cell count and macrophage cell count were significantly associated with neutralized sulfate and several correlated measurements. Increases in neutrophils in BAL were associated with zinc. There were no significant differences in CBC parameters or blood vessel wall thickness by histopathology. The association between neutrophils increases and zinc raises the possibility that metals play a role in this response.

Los contaminantes atmosfericos urbanos son factores de riesgo significativos para el asma y la neumonia en ninos: influencia del lugar de medicion de los contaminantes

BACKGROUND Air pollution is associated with a substantial burden on human health; however, the most important pollutants may vary with location. Proper monitoring is necessary to determine the effect of these pollutants on respiratory health. OBJECTIVES This study was designed to evaluate the role of outdoor, indoor and personal exposure to combustion-related pollutants NO(2) and O(3) on respiratory health of children in a non-affluent urban area of São Paulo, Brazil. METHODS Levels of NO(2) and O(3) were continuously measured in outdoor and indoor air, as well as personal exposure, for 30 days using passive measurement monitors. Respiratory health was assessed with a Brazilian version of the ISAAC questionnaire. RESULTS Complete data were available from 64 children, aged 6-10 years. Respiratory morbidity was high, with 43 (67.2%) reporting having had wheezing at any time, 27 (42.2%) wheezing in the last month, 17 (26.6%) asthma at any time and 21 (32.8%) pneumonia at any time. Correlations between levels of NO(2) and O(3) measured in the three locations evaluated were poor. Levels of NO(2) in indoor air and personal exposure to O(3) were independently associated with asthma (both cases P=.02), pneumonia (O(3), P=.02) and wheezing at any time (both cases P<.01). No associations were seen between outdoor NO(2) and O(3) and respiratory health. CONCLUSIONS Exposure to higher levels of NO(2) and O(3) was associated with increased risk for asthma and pneumonia in children. Nonetheless, the place where the pollutants are measured influences the results. The measurements taken in indoor and personal exposure were the most accurate.

Urban, traffic- related particles and lung tumors in urethane treated mice.

OBJECTIVE: The present study was designed to evaluate the effects of urban, traffic-related, fine particulate matter (PM2.5) on mice lung tumorigenesis under controlled exposure conditions. METHODS: Four groups of female Swiss mice were treated with intraperitonial injections of urethane and saline solution. Urethane was used to start the carcinogenesis process. The animals were housed in two chambers receiving filtered and polluted air. In the polluted air chamber, pollutant levels were low. After two months of exposure, the animals were euthanized and lung tumoral nodules were counted. RESULTS: Saline-treated animals showed no nodules. Urethane-treated animals showed 2.0+2.0 and 4.0+3.0 nodules respectively, in the filtered and non-filtered chambers (p = 0.02), thus showing experimental evidence of increased carcinogenic-induced lung cancer with increasing PM2.5 exposure. CONCLUSION: Our data support the concept that low levels of PM2.5 may increase the risk of developing lung tumors.

Longitudinal study of lung function in pregnant women: Influence of parity and smoking

OBJECTIVES: To evaluate pulmonary function in the first and third trimesters of pregnancy and analyze the influence of parity and smoking on spirometry parameters. METHODS: This longitudinal prospective study included a cohort of 120 pregnant women. The inclusion criteria were as follows: singleton pregnancy, gestational age less than 13.86 weeks, and no preexisting maternal diseases. The exclusion criteria were as follows: change of address, abortion, and inadequate spirometry testing. ClinicalTrials.gov: NCT02807038. RESULTS: A decrease in values of forced vital capacity and forced expiratory volume were noted in the first second from the first to third trimester. In the first and third trimesters, multiparous women demonstrated lower absolute forced vital capacity and forced expiratory volume values in the first second compared with nulliparous women (p<0.0001 and p=0.001, respectively). Multiparous women demonstrated reduced forced expiratory flow in 25% to 75% of the maneuver compared with nulliparous women in the first (p=0.005) and third (p=0.031) trimesters. The absolute values of forced expiratory flow in 25% to 75%, forced expiratory volume in the first second and predicted peak expiratory flow values in the third trimester were higher in smokers compared with nonsmokers (p=0.042, p=0.039, p=0.024, and p=0.021, respectively). CONCLUSION: There was a significant reduction in forced vital capacity and forced expiratory volume values in the first second during pregnancy. Parity and smoking significantly influence spirometric variables.