Efeito agudo do exercício aeróbio em diferentes intensidades no transporte mucociliar de pacientes com DPOC / Acute effect of aerobic exercise in different intensities in mucociliary clearance of patients with COPD

Experimental. Objetivo(s) do estudo: Analisar o efeito agudo do exercício aeróbio em diferentes intensidades no transporte mucociliar de pacientes com DPOC, bem como investigar possíveis associações do sistema nervoso autônomo nesta resposta. Metodologia: Foram analisados 22 pacientes com DPOC que realizaram avaliação inicial para coleta de dados pessoais e espirometria a fim de avaliar a função pulmonar. Realizou-se um teste progressivo em esteira ergométrica para prescrição do exercício aeróbio. Por fim foram realizadas duas sessões de exercício aeróbio randomizadas em esteira ergométrica com intensidade de 60% e 90% do pico da velocidade atingida no teste incremental(vVO2 pico) com pelo menos 24 horas de descanso entre elas. O transporte mucociliar foi avaliado antes e após realização do exercício por meio do teste do tempo de trânsito da sacarina (TTS). A avaliação da modulação autonômica foi realizada por meio da variabilidade da frequência cardíaca (VFC) a qual prosseguiu durante todo o protocolo. Resultados: Os valores obtidos no teste de TTS dos pacientes com DPOC após exercício aeróbio a 60% da vVO2 pico (9,08 ± 4,96 minutos) foi menor comparado ao TTS antes do exercício (11,96 ± 6,31; p = 0,005). O que também ocorreu após exercício aeróbio a 90% da vVO2pico (8,90 ± 4,21 minutos) quando comparado ao momento basal (12,94 ± 7,22; p = 0,023). As análises de correlação entre os valores finais de TTS e índices da VFC não apontaram diferenças significativas.Conclusões: Pacientes com DPOC apresentaram aceleração da transportabilidade mucociliar frente a uma sessão de exercício aeróbio. Não foi possível observar associação da modulação autonômica nesta resposta após o exercício...

Design of the Study: Clinical Trial. Objective (s): To analyze the acute effect of aerobic exercise at different intensities in mucociliary clearance in patients with COPD, and to investigate possible associations of the autonomic nervous system in this response. Methods: 22 COPD patients underwent an initial evaluation for collecting personal data and spirometry to assess lung function. It was performed a progressive treadmill test for aerobic exercise prescription. Finally two randomized sessions of aerobic exercise with intensity of 60 % and 90 % of peak speed reached during the incremental test ( vVO2 peack ) were performed with at least 24 hours of rest between them. The mucociliary clerance was assessed before and after the exercise sessions by testing the saccharin transit time (STT). Assessment of autonomic modulation was performed by heart rate variability (HRV) which continued throughout the protocol. Results:The values obtained in the STT test after aerobic exercise at 60 % of vVO2 peack (9,08 minutes ± 4,96 ) was lower when compared to the STT before exercise ( 11,96 ± 6,31, p = 0,005 ) . That response also occurred after aerobic exercise at 90% of vVO2 peack ( 8,90 ± 4,21 min ) compared to baseline ( 12,94± 7,22 , p = 0,023 ). Correlation analysis between the final values of STT test and HRV indexes did not show significant differences. Conclusions: Patients with COPD showed acceleration of mucociliary clerance right after a session of aerobic exercise. It was not possible to observe the association of autonomic modulation in this response...

Chronic exposure of diesel exhaust particles induces alveolar enlargement in mice.

BACKGROUND: Diesel exhaust particles (DEPs) are deposited into the respiratory tract and are thought to be a risk factor for the development of diseases of the respiratory system. In healthy individuals, the timing and mechanisms of respiratory tract injuries caused by chronic exposure to air pollution remain to be clarified. METHODS: We evaluated the effects of chronic exposure to DEP at doses below those found in a typical bus corridor in Sao Paulo (150 µg/m3). Male BALB/c mice were divided into mice receiving a nasal instillation: saline (saline; n = 30) and 30 µg/10 µL of DEP (DEP; n = 30). Nasal instillations were performed five days a week, over a period of 90 days. Bronchoalveolar lavage (BAL) was performed, and the concentrations of interleukin (IL)-4, IL-10, IL-13 and interferon-gamma (INF-γ) were determined by ELISA-immunoassay. Assessment of respiratory mechanics was performed. The gene expression of Muc5ac in lung was evaluated by RT-PCR. The presence of IL-13, MAC2+ macrophages, CD3+, CD4+, CD8+ T cells and CD20+ B cells in tissues was analysed by immunohistochemistry. Bronchial thickness and the collagen/elastic fibers density were evaluated by morphometry. We measured the mean linear intercept (Lm), a measure of alveolar distension, and the mean airspace diameter (D0) and statistical distribution (D2). RESULTS: DEP decreased IFN-γ levels in BAL (p = 0.03), but did not significantly alter IL-4, IL-10 and IL-13 levels. MAC2+ macrophage, CD4+ T cell and CD20+ B cell numbers were not altered; however, numbers of CD3+ T cells (p ≤ 0.001) and CD8+ T cells (p ≤ 0.001) increased in the parenchyma. Although IL-13 (p = 0.008) expression decreased in the bronchiolar epithelium, Muc5ac gene expression was not altered in the lung of DEP-exposed animals. Although respiratory mechanics, elastic and collagen density were not modified, the mean linear intercept (Lm) was increased in the DEP-exposed animals (p ≤ 0.001), and the index D2 was statistically different (p = 0.038) from the control animals. CONCLUSION: Our data suggest that nasal instillation of low doses of DEP over a period of 90 days results in alveolar enlargement in the pulmonary parenchyma of healthy mice.

Organic and inorganic fractions of diesel exhaust particles produce changes in mucin profile of mouse trachea explants.

Diesel exhaust particles (DEP) contain organic and inorganic elements that produce damage to the respiratory epithelium. The aim of this study was to determine the mucus profile of tracheal explants exposed to either crude diesel exhaust particles (DEP) or DEP treated with nitric acid (DEP/NA), with hexane (DEP/HEX), or with methanol (DEP/MET) at concentrations of 50 and 100 µg/ml for 30 and 60 min. Tracheal explants were subjected to morphometric analyses to study acidic (AB+), neutral (PAS+), and mixed (AB+/PAS+) mucus production and vacuolization (V). Incubation with 50 µg/ml crude DEP resulted in a rise in acid mucus production, an increase in vacuolization at 30 min, and reduction in neutral mucus at 30 and 60 min. Tracheas exposed to DEP/MET at 50 µg/ml for 30 or 60 min resulted in a significant decrease in neutral mucus production and an elevation in acid mucus production. DEP/HEX increased vacuolization at both 50 and 100 µg/ml at 30 and 60 min of exposure. Treatment with 50 µg/ml for 30 or 60 min significantly elevated mixed mucus levels. These results suggest that DEP appear to be more toxic when administered in combination with HEX or MET. DEP/MET modified the mucus profile of the epithelium, while DEP/HEX altered mucus extrusion, and these responses might be due to bioavailability of individual elements in DEP fractions.

Nasal Mucociliary Clearance in Subjects With COPD After Smoking Cessation.

BACKGROUND: Exposure to cigarette smoke causes significant impairment in mucociliary clearance (MCC), which predisposes patients to secretion retention and recurrent airway infections that play a role in exacerbations of COPD. To determine whether smoking cessation may influence MCC and frequency of exacerbations, the following groups were evaluated: ex-smokers with COPD, smokers with COPD, current smokers with normal lung function, and nonsmokers with normal lung function. METHODS: Ninety-three subjects were divided into 4 groups: ex-smokers with COPD (n = 23, 62.4 ± 8.0 y, 13 males), smokers with COPD (n = 17, 58.2 ± 8.0 y, 6 males), current smokers (n = 27, 61.5 ± 6.4 y, 17 males), and nonsmokers (n = 26, 60.8 ± 11.3 y, 7 males). MCC was evaluated using the saccharin transit time (STT) test, and the frequency of exacerbations in the last year was assessed by questionnaire. The Kruskal-Wallis test followed by Dunn's test were used to compare STT among groups, and the Goodman test was used to compare the frequency of exacerbations. RESULTS: STT of smokers with COPD (16.5 [11-28] min; median [interquartile range 25-75%]) and current smokers (15.9 [10-27] min) was longer compared with ex-smokers with COPD (9.7 [6-12] min) and nonsmokers (8 [6-16] min) (P < .001). There was no difference in STT values between smokers with COPD and current smokers, and these values in ex-smokers with COPD were similar to the control group (P > .05). The frequency of exacerbations was lower in ex-smokers with COPD compared with smokers with COPD. CONCLUSIONS: One year after smoking cessation, subjects with COPD had improved mucociliary clearance.

Correlation between heart rate variability indexes and aerobic physiological variables in patients with COPD.

BACKGROUND AND OBJECTIVE: Previous studies have shown a relationship between the level of physical fitness and autonomic variables. However, these relationships have not been investigated in patients with chronic obstructive pulmonary disease (COPD). The objective of this study was to correlate the resting heart rate variability (HRV) indexes with aerobic physiological variables obtained at a maximal exercise test in patients with COPD. METHODS: Thirty-seven patients with COPD (63 (59-70) years; 46 (35.4-63.7) forced expiratory volume in 1 s (FEV1)%) underwent assessment of autonomic modulation at rest for 20 min to determine the HRV indexes in time and frequency domains. Soon after that, the patients performed an incremental exercise test to determine the anaerobic threshold (GET), the peak oxygen uptake (VO 2PEAK) and the velocity corresponding to VO 2PEAK (vVO 2PEAK). RESULTS: The indexes that express parasympathetic component as RMSSD (11.4 [7.5-23.8], HF (ms(2)) (35 [17-195] and SD1 (8.1 [5.3-16.8]), correlated with GET (r = 0.39; r = 0.43; r = 0.39 respectively). The indexes that represent the overall variability, SDNN (19.5 [13.9-28.8]), LF (ms(2)) (111 [38-229]), and SD2 (26.8 [18.6-35.4]) correlated with vVO 2PEAK (r = 0.37; r = 0.38; r = 0.37; r = 0.44; r = 0.43; r = 0.46 respectively). Likewise, the indexes LF (ms(2)), LF (nu) (63.2 [46-77,9]), HF (nu) (36.8 [22.1-54]), and LF/HF (1.7 [0.9-3.5]) correlated with VO 2PEAK (r = 0.35; r = 0.35; r = -0.35; r = 0.40 respectively). CONCLUSIONS: This study demonstrated that HRV indexes at rest may become a predictive tool for aerobic capacity in COPD patients after the development of more consistent methods.

Cigarette smoke dissociates inflammation and lung remodeling in OVA-sensitized and challenged mice.

We evaluated the effects of cigarette smoke (CS) on lung inflammation and remodeling in a model of ovalbumin (OVA)-sensitized and OVA-challenged mice. Male BALB/c mice were divided into 4 groups: non-sensitized and air-exposed (control); non-sensitized and exposed to cigarette smoke (CS), sensitized and air-exposed (OVA) (50 µg+OVA 1% 3 times/week for 3 weeks) and sensitized and cigarette smoke exposed mice (OVA+CS). IgE levels were not affected by CS exposure. The increases in total bronchoalveolar fluid cells in the OVA group were attenuated by co-exposure to CS, as were the changes in IL-4, IL-5, and eotaxin levels as well as tissue elastance (p<0.05). In contrast, only the OVA+CS group showed a significant increase in the protein expression of IFN-γ, VEGF, GM-CSF and collagen fiber content (p<0.05). In our study, exposure to cigarette smoke in OVA-challenged mice resulted in an attenuation of pulmonary inflammation but led to an increase in pulmonary remodeling and resulted in the dissociation of airway inflammation from lung remodeling.

Salbutamol improves markers of epithelial function in mice with chronic allergic pulmonary inflammation.

We investigated the effects of salbutamol on the markers of epithelial function in a murine model of chronic allergic pulmonary inflammation by recording the ciliary beat frequency (CBF) and the transepithelial potential difference (PD) in vivo. Mice were sensitized and received four challenges of ovalbumin (OVA group) or 0.9% saline (control group). Forty-eight hours after the 4th inhalation, we observed eosinophilia in the bronchoalveolar lavage and epithelium remodeling with stored acid mucus in the OVA group (P < 0.001). No difference in the baseline CBF was noticed between the groups; however, the OVA group had a significantly lower baseline PD (P = 0.013). Salbutamol increased the CBF in all groups studied, and the dose response curve to salbutamol increased the PD in the OVA group from 10(-4)M to 10(-2)M. We suggest that salbutamol affects the CBF and the depth of the periciliary layer, which, in great part, determines the ability of the cilia to propel the mucus layer. This effect may have a positive impact on airway mucociliary transport in asthma and may have clinical implications.

Repeated stress reduces mucociliary clearance in animals with chronic allergic airway inflammation.

We evaluated if repeated stress modulates mucociliary clearance and inflammatory responses in airways of guinea pigs (GP) with chronic inflammation. The GP received seven exposures of ovalbumin or saline 0.9%. After 4th inhalation, animals were submitted to repeated forced swim stressor protocol (5x/week/2 weeks). After 7th inhalation, GP were anesthetized. We measured transepithelial potential difference, ciliary beat frequency, mucociliary transport, contact angle, cough transportability and serum cortisol levels. Lungs and adrenals were removed, weighed and analyzed by morphometry. Ovalbumin-exposed animals submitted to repeated stress had a reduction in mucociliary transport, and an increase on serum cortisol, adrenals weight, mucus wettability and adhesivity, positive acid mucus area and IL-4 positive cells in airway compared to non-stressed ovalbumin-exposed animals (p<0.05). There were no effects on eosinophilic recruitment and IL-13 positive cells. Repeated stress reduces mucociliary clearance due to mucus rheological-property alterations, increasing acid mucus and its wettability and adhesivity. These effects seem to be associated with IL-4 activation.

Acute cardiovascular and inflammatory toxicity induced by inhalation of diesel and biodiesel exhaust particles.

Analysis of fuel emissions is crucial for understanding the pathogenesis of mortality because of air pollution. The objective of this study is to assess cardiovascular and inflammatory toxicity of diesel and biodiesel particles. Mice were exposed to fuels for 1 h. Heart rate (HR), heart rate variability, and blood pressure were obtained before exposure, as well as 30 and 60 min after exposure. After 24 h, bronchoalveolar lavage, blood, and bone marrow were collected to evaluate inflammation. B100 decreased the following emission parameters: mass, black carbon, metals, CO, polycyclic aromatic hydrocarbons, and volatile organic compounds compared with B50 and diesel; root mean square of successive differences in the heart beat interval increased with diesel (p < 0.05) compared with control; low frequency increased with diesel (p < 0.01) and B100 (p < 0.05) compared with control; HR increased with B100 (p < 0.05) compared with control; mean corpuscular volume increased with B100 compared with diesel (p < 0.01), B50, and control (p < 0.001); mean corpuscular hemoglobin concentration decreased with B100 compared with B50 (p < 0.001) and control (p < 0.05); leucocytes increased with B50 compared with diesel (p < 0.05); platelets increased with B100 compared with diesel and control (p < 0.05); reticulocytes increased with B50 compared with diesel, control (p < 0.01), and B100 (p < 0.05); metamyelocytes increased with B50 and B100 compared with diesel (p < 0.05); neutrophils increased with diesel and B50 compared with control (p < 0.05); and macrophages increased with diesel (p < 0.01), B50, and B100 (p < 0.05) compared with control. Biodiesel was more toxic than diesel because it promoted cardiovascular alterations as well as pulmonary and systemic inflammation.

Effects of residual oil fly ash (ROFA) in mice with chronic allergic pulmonary inflammation.

Exposure to particulate matter (PM) air pollution is associated with increased asthma morbidity. Residual oil flash ash (ROFA) is rich in water-soluble transition metals, which are involved in the pathological effects of PM. The objective of this study was to investigate the effects of intranasal administration of ROFA on pulmonary inflammation, pulmonary responsiveness, and excess mucus production in a mouse model of chronic pulmonary allergic inflammation. BALB/c mice received intraperitoneal injections of ovalbumin (OVA) solution (days 1 and 14). OVA challenges were performed on days 22, 24, 26, and 28. After the challenge, mice were intranasally instilled with ROFA. After forty-eight hours, pulmonary responsiveness was performed. Mice were sacrificed, and lungs were removed for morphometric analysis. OVA-exposed mice presented eosinophilia in the bronchovascular space (p < .001), increased pulmonary responsiveness (p < .001), and epithelial remodeling (p = .003). ROFA instillation increased pulmonary responsiveness (p = .004) and decreased the area of ciliated cells in the airway epithelium (p = .006). The combined ROFA instillation and OVA exposure induced a further increase in values of pulmonary responsiveness (p = .043) and a decrease in the number of ciliated cells in the airway epithelium (p = .017). PM exposure results in pulmonary effects that are more intense in mice with chronic allergic pulmonary inflammation.