Nanoencapsulation of a glucocorticoid improves barrier function and anti-inflammatory effect on monolayers of pulmonary epithelial cell lines.

The anti-inflammatory effect of polymeric deflazacort nanocapsules (NC-DFZ) was investigated, and possible improvement of epithelial barrier function using filter grown monolayers of Calu-3 cells was assessed. NC prepared from poly(ε-caprolactone) (PCL) had a mean size around 200nm, slightly negative zeta potential (∼-8mV), and low polydispersity index (<0.10). Encapsulation of DFZ had an efficiency of 85%. No cytotoxic effects were observed at particle concentration of 9.85×1011NC/ml, which was therefore chosen to evaluate the effect of NC-DFZ at 1% (w/v) of PCL and 0.5% (w/v) of DFZ on the epithelial barrier function of Calu-3 monolayers. Nanoencapsulated drug at 0.5% (w/v) increased transepithelial electrical resistance and decreased permeability of the paracellular marker sodium fluorescein, while non-encapsulated DFZ failed to improve these parameters. Moreover, NC-DFZ reduced the lipopolysaccharide (LPS) mediated secretion of the inflammatory marker IL-8. In vitro dissolution testing revealed controlled release of DFZ from nanocapsules, which may explain the improved effect of DFZ on the cells. These data suggest that nanoencapsulation of pulmonary delivered corticosteroids could be advantageous for the treatment of inflammatory conditions, such as asthma and chronic obstructive pulmonary diseases.

Avaliação do citoesqueleto e da barreira endotelial pulmonar na malária experimental / Evaluation of the cytoskeleton and pulmonary endothelial barrier in experimental malaria

Infecções por Plasmodium sp. podem levar a um quadro respiratório grave, com complicações pulmonares denominadas lesão pulmonar aguda e síndrome do desconforto respiratório agudo (LPA/SDRA). Inflamação aguda, lesão do endotélio alveolar e do parênquima pulmonar, disfunção e aumento da permeabilidade da barreira alvéolo-capilar e, consequente, formação de edema, caracterizam esta síndrome. O modelo experimental, que utiliza o parasita murino Plasmodium berghei ANKA e camundongos da linhagem DBA/2, é empregado no estudo de mediadores imunológicos e fatores que propiciam o estabelecimento das lesões pulmonares associados à LPA/SDRA. Diversos estímulos podem atuar diretamente no aumento da permeabilidade endotelial por meio da desestabilização dos microtúbulos, rearranjo dos microfilamentos de actina e contração das células endoteliais, via sinalização de Rho-GTPases, causando disfunção da barreira endotelial. Desta forma, este trabalho tem como objetivo avaliar as alterações do citoesqueleto em células endoteliais primárias pulmonares de camundongos DBA/2 (CEPP-DBA/2), as vias de sinalização das principais Rho-GTPases e o estresse oxidativo, causados pela presença de eritrócitos parasitados com esquizontes de P. berghei ANKA (EP-PbA). As CEPP-DBA/2 foram estimuladas com TNF, VEGF ou IFNγ, em diferentes tempos de exposição, seguido da incubação com EP-PbA. Assim, foram realizados ensaios de imunofluorescência para análise do rearranjo de microfilamentos de actina e da desestabilização de microtúbulos. As vias de sinalização das Rho-GTPases foram avaliadas por Western blot, para as expressões proteicas de RhoA, Cdc42 e MLC. Além disso, ensaio fluorométrico foi realizado para detectar a produção de espécies reativas de oxigênio, resultantes do estímulo com eritrócitos parasitados. CEPP-DBA/2 estimuladas por EP-PbA, VEGF, TNF ou IFNγ, em associação ou não, apresentaram alterações morfológicas nos microfilamentos de actina e aumento dos espaços interendoteliais. Imagens de imunofluorescência também mostram desestabilização de microtúbulos e desfosforilação de FAK, causadas por EP-PbA. Os ensaios de permeabilidade validam que os eritrócitos parasitados com formas maduras de P. berghei induziram aumento da permeabilidade microvascular nas CEPP-DBA/2. Além disso, estas células, estimuladas com EP-PbA, demonstraram elevada produção de espécies reativas de oxigênio (EROs), o que pode estar contribuindo com o desenvolvimento de estresse oxidativo e com a injúria endotelial, assim como, com o aumento da permeabilidade vascular. O mais interessante é que estas alterações endoteliais podem estar relacionadas ao aumento da razão RhoA/Cdc42, da expressão proteica de MLC fosforilada e do sinal de ativação de RhoA. Em conjunto, estes resultados mostram envolvimento dos eritrócitos parasitados com esquizontes de Plasmodium berghei ANKA na desorganização do citoesqueleto e na disfunção da barreira alvéolo-capilar, via RhoA/Rho-kinase, o que pode estar contribuindo com a patogênese da LPA/SDRA associada à malária

Infections by Plasmodium sp. can lead to a serious respiratory condition with pulmonary complications, named acute lung injury and acute respiratory distress syndrome (ALI/ARDS). Acute inflammation, alveolar endothelium and lung parenchyma injuries, dysfunction and increased permeability of the pulmonary alveolar-capillary barrier and consequent formation of edema characterize this syndrome. Several stimuli can directly increase endothelial permeability through actin microfilaments rearrangement, via Rho- GTPases signaling, leading to endothelial barrier dysfunction. DBA/2 mice infected with Plasmodium berghei ANKA develop ALI/ARDS similar to that observed in humans. The purpose of this research was to assess cytoskeletal changes in DBA/2 mice primary microvascular lung endothelial cells (PMLEC), verify the signaling pathways of the Rho- GTPases and analyze the oxidative stress on these cells in the presence of P. berghei ANKA-infected red blood cells (PbA-iRBC). PMLEC were stimulated by TNF, VEGF or IFNγ followed by incubation with PbA-iRBC. Immunofluorescence assays were performed to analyze actin microfilaments rearrangement and microtubules destabilization. Western blot for RhoA, Cdc42 and MLC proteins were conducted to assess alterations in signaling pathways of Rho-GTPases. In addition, a fluorimetric assay was performed to detect the production of reactive oxygen species resulting from PbA-iRBC stimulus. P. berghei ANKA, VEGF, TNF and IFNγ stimuli, in association or not, caused morphological disturbances in actin microfilaments of PMLEC and an increase of intercellular spaces. Moreover, immunofluorescence images showed microtubules destabilization and FAK dephosphorylation in these cells, caused by PbA-iRBC. The permeability assay showed that PbA-iRBC induced an increase of microvascular permeability in PMLEC. In addition, PMLEC stimulated by PbA-iRBC, showed elevated production of ROS, which may be contributing to oxidative stress and increasing the damage of endothelial cells, as well as an increase of vascular permeability. Interestingly, these endothelial changes may be related to the increased RhoA/Cdc42 protein expressions ratio, augmented protein expression of phosphorylated MLC and RhoA activation signal. Taken together, these data demonstrate the involvement of P. berghei ANKA-infected red blood cells in cytoskeleton disorganization and alveolar-capillary barrier dysfunction, through of RhoA / Rho-kinase signaling pathway, which may contribute to ALI/ARDS pathogenesis

Acute lung injury induced by whole gastric fluid: hepatic acute phase response contributes to increase lung antiprotease protection.

BACKGROUND: Gastric contents aspiration in humans is a risk factor for severe respiratory failure with elevated mortality. Although aspiration-induced local lung inflammation has been studied in animal models, little is known about extrapulmonary effects of aspiration. We investigated whether a single orotracheal instillation of whole gastric fluid elicits a liver acute phase response and if this response contributes to enrich the alveolar spaces with proteins having antiprotease activity. METHODS: In anesthetized Sprague-Dawley rats receiving whole gastric fluid, we studied at different times after instillation (4 h -7 days): changes in blood cytokines and acute phase proteins (fibrinogen and the antiproteases alpha1-antitrypsin and alpha2-macroglobulin) as well as liver mRNA expression of the two antiproteases. The impact of the systemic changes on lung antiprotease defense was evaluated by measuring levels and bioactivity of antiproteases in broncho-alveolar lavage fluid (BALF). Markers of alveolar-capillary barrier derangement were also studied. Non-parametric ANOVA (Kruskall-Wallis) and linear regression analysis were used. RESULTS: Severe peribronchiolar injury involving edema, intra-alveolar proteinaceous debris, hemorrhage and PMNn cell infiltration was seen in the first 24 h and later resolved. Despite a large increase in several lung cytokines, only IL-6 was found elevated in blood, preceding increased liver expression and blood concentration of both antiproteases. These changes, with an acute phase response profile, were significantly larger for alpha2-macroglobulin (40-fold increment in expression with 12-fold elevation in blood protein concentration) than for alpha1-antitrypsin (2-3 fold increment in expression with 0.5-fold elevation in blood protein concentration). Both the increment in capillary-alveolar antiprotease concentration gradient due to increased antiprotease liver synthesis and a timely-associated derangement of the alveolar-capillary barrier induced by aspiration, contributed a 58-fold and a 190-fold increase in BALF alpha1-antitrypsin and alpha2-macroglobulin levels respectively (p < 0.001). CONCLUSIONS: Gastric contents-induced acute lung injury elicits a liver acute phase response characterized by increased mRNA expression of antiproteases and elevation of blood antiprotease concentrations. Hepatic changes act in concert with derangement of the alveolar capillary barrier to enrich alveolar spaces with antiproteases. These findings may have significant implications decreasing protease burden, limiting injury in this and other models of acute lung injury and likely, in recurrent aspiration.

High postoperative serum levels of surfactant type B as novel prognostic markers for congenital heart surgery.

OBJECTIVE: Congenital heart diseases are observed in 5 to 8 of every 1000 live births. The presence of a valuable biomarker during the surgical periods may aid the clinician in a more accurate prognosis during treatment. METHODS: For this reason, surfactant protein B plasma levels may help to evaluate patients with cardiac problems diminishing the alveolocapillary membrane stability. In this study, plasma levels of this biomarker were measured in the preoperative and postoperative periods. This study was conducted to detect the differences between pulmonary hypertensive and normotensive patients. The differences before and after cardiopulmonary bypass were examined. RESULTS: The differences in cardiopulmonary bypass time, cross-clamp time , inotropic support dose, and duration of intensive care of patients with and without pulmonary hypertensive were found to be statistically significant (P<0.05). The results revealed that this pathophysiological state was related to other variables that were studied. We believe that the differences in preoperative and postoperative SPB levels could be attributed to alveolocapillary membrane damage and alveolar surfactant dysfunction. We found that this pathophysiological condition was significantly associated with postoperative parameters. CONCLUSION: The findings of the current study showed that surfactant protein B was present in the blood of patients with a congenital heart disease during the preoperative period. Long by-pass times may exert damage to the alveolocapillary membrane in patients with pulmonary hypertension and preoperative heart failure, and it is recommended to keep the option of surfactant therapy in mind during the postoperative course at the intensive care unit before preparing the patients for extubation.

High postoperative serum levels of surfactant type B as novel prognostic markers for congenital heart surgery / Níveis séricos pós-operatórios tipo surfactante B elevados como novos marcadores prognósticos para cirurgia cardíaca congênita

Objective: Congenital heart diseases are observed in 5 to 8 of every 1000 live births. The presence of a valuable biomarker during the surgical periods may aid the clinician in a more accurate prognosis during treatment. Methods: For this reason, surfactant protein B plasma levels may help to evaluate patients with cardiac problems diminishing the alveolocapillary membrane stability. In this study, plasma levels of this biomarker were measured in the preoperative and postoperative periods. This study was conducted to detect the differences between pulmonary hypertensive and normotensive patients. The differences before and after cardiopulmonary bypass were examined. Results: The differences in cardiopulmonary bypass time, cross-clamp time , inotropic support dose, and duration of intensive care of patients with and without pulmonary hypertensive were found to be statistically significant (P<0.05). The results revealed that this pathophysiological state was related to other variables that were studied. We believe that the differences in preoperative and postoperative SPB levels could be attributed to alveolocapillary membrane damage and alveolar surfactant dysfunction. We found that this pathophysiological condition was significantly associated with postoperative parameters. Conclusion: The findings of the current study showed that surfactant protein B was present in the blood of patients with a congenital heart disease during the preoperative period. Long by-pass times may exert damage to the alveolocapillary membrane in patients with pulmonary hypertension and preoperative heart failure, and it is recommended to keep the option of surfactant therapy in mind during the postoperative course at the intensive care unit before preparing the patients for extubation. .

Objetivo: As cardiopatias congênitas são observadas em 5 a 8 em cada 1.000 nascidos vivos. A presença de um biomarcador importante durante os períodos cirúrgicos pode auxiliar o clínico a um prognóstico mais preciso durante o tratamento. Métodos: Por esta razão, os níveis plasmáticos de proteína B do surfactante podem ajudar a avaliar os pacientes com problemas cardíacos, diminuindo a estabilidade da membrana alvéolo-capilar. Neste estudo, os níveis plasmáticos deste biomarcador foram medidos nos períodos pré-operatório e pós-operatório. Este estudo foi realizado para detectar as diferenças entre pacientes hipertensos e normotensos em nível pulmonar. As diferenças antes e depois da circulação extracorpórea foram examinadas. Resultados: As diferenças no tempo de circulação extracorpórea, tempo de pinçamento, a dose de drogas vasoativas, e a duração da terapia intensiva de pacientes com e sem hipertensão pulmonar foram estatisticamente significativas (P<0,05). Os resultados revelaram que este estado fisiopatológico foi relacionado a outras variáveis que foram estudadas. Acreditamos que as diferenças nos níveis de SPB pré-operatório e pós-operatório pode ser atribuída a danos na membrana alvéolo-capilar e disfunção do surfactante alveolar. Descobrimos que esta condição fisiopatológica foi significativamente associada com parâmetros pós-operatórios. Conclusão: Os resultados do estudo mostraram que a proteína B surfactante estava presente no sangue de pacientes com doença cardíaca congênita no pré-operatório. Longos tempos de circulação extracorpórea podem exercer danos na membrana alvéolo-capilar em pacientes com ...

Efeito do tempo de aplicação da pressão positiva expiratória sobre a depuração pulmonar do 99mTc-DTPA / Effect of application time of positive expiratory pressure on lung clearance of 99mTc-DTPA

Introdução: A taxa de depuração pulmonar do 99mTcDTPAconstitui um índice da permeabilidade pulmonar. A aplicação dapressão positiva expiratória (EPAP), um recurso fisioterapêutico,promove aumento da expansão pulmonar, entretanto são escassosos estudos abordando a associação entre o tempo de aplicação desterecurso e a permeabilidade pulmonar. Objetivo: Comparar o tempode depuração pulmonar do 99mTc-DTPA no 15º e 30º minuto deaplicação da EPAP nas pressões de 10 e 15 cmH2O. Hipotetiza-seque a aplicação de apenas 15 minutos da técnica já poderia influenciarpositivamente o aumento do volume pulmonar. Material e métodos:Mensurou-se a taxa de depuração pulmonar do 99mTc-DTPAna posição sentada em indivíduos hígidos (n = 20) respirando sob oefeito de 10 e 15 cmH2O de EPAP, após avaliou-se o comportamentodo T1/2 no 15º e 30º minuto. Resultados: Observou-se o aumentoda taxa de depuração quando 15 cmH2O de EPAP foi aplicada (p= 0,012), porém não houve alteração com 10 cmH2O (p = 0,064).Não houve diferença estatisticamente significativa no T1/2 do 99mTc--DTPA do 15º minuto (p = 0,182) para o 30º (p = 0,489). Conclusão:Os resultados demonstraram o efeito de 15 cmH2O da EPAP noaumento da depuração pulmonar do 99mTc-DTPA sugerindo nãohaver diferença entre o 15º e 30º minuto.

Introduction: The pulmonary clearance rate of 99mTc-DTPA isindex of lung permeability. The application of expiratory positiveairway pressure (EPAP), a physical therapy tool, promotes increasein pulmonary volume, however there are few studies addressingthe association between the application time of this resource andlung permeability. Objective: To compare the time of 99mTc-DTPAlung clearance in the 15º and 30º minute of EPAP at pressures 10cmH2O and 15 cmH2O. It is hypothesized that the applicationof 15 minutes of EPAP could positively influence the increase inpulmonary volume. Methods: We measured the pulmonary clearancerate of 99mTc-DTPA in a sitting position in healthy individuals (n= 20) breathing under the effect of 10 and 15 cmH2O of EPAP,after that we evaluate the behavior of T1/2 at 15º and 30º minute.Results: We observed an increase in clearance rate with 15 cmH2OEPAP (p = 0,012), but there was no change with 10 cmH2O (p= 0,064). There was no statistically significant difference in T1/2 of99mTc-DTPA in the 15º minute (p = 0,182) to the 30º minute (p =0,489). Conclusion: The results demonstrated the effect of 15 cmH2OEPAP in the increase of the pulmonary clearance of 99mTc-DTPAsuggesting no difference between 15º and 30º minutes.

The effect of exercise on the oxidative stress induced by experimental lung injury.

AIM: The effects of physical exercise on oxidative stress parameters and immunocontent of NF-кß/p65 in lung of rats submitted to lung injury, as well as its possible protective effect on the changes in the alveolar-capillary barrier (total cell count, lactate dehydrogenase and total protein) in the bronchoalveolar lavage fluid (BALF) and the inflammatory infiltration in the pulmonary parenchyma were evaluated. MAIN METHODS: Wistar rats were submitted to two months of physical exercise and after this period, lung injury was induced by intratracheal instillation of lipopolysaccharide (dose of 100 µg/100 g body weight). Twelve hours after injury, the animals were sacrificed and lung and BALF were collected. KEY FINDINGS: Results showed an increase in reactive species production, lipid peroxidation, oxidative damage to protein, as well as in nitrite levels and NF-кß/p65 immunocontent in lung of rats submitted to lung injury. Physical exercise was able to totally prevent the increase in reactive species, nitrite levels and NF-кß/p65 immunocontent, but partially prevented the damage to protein. Superoxide dismutase and catalase were not changed in lung injury group, but the activities of these enzymes were increased in lung injury plus exercise group. Non-enzymatic antioxidant capacity, glutathione content and glutathione peroxidase were decreased and exercise totally prevented such effects. Rats subjected to lung injury presented an increase in total cell, lactate dehydrogenase and total protein; exercise partially prevented the increase in lactate dehydrogenase. SIGNIFICANCE: These findings suggest that physical exercise may prevent, at least partially, the oxidative damage caused by experimental lung injury, suggesting that exercise may have an important role as protector in this condition.

Entendendo a estrutura microscópica e submicroscópica da barreira alvéolo-capilar na lesão pulmonar aguda / Understanding the microscopic and submicroscopic structure of the alveolar-capillary membrane in acute lung injury

A lesão pulmonar aguda/síndrome do desconforto respiratório agudo (LPA/SDRA) pode ser induzida por diferentes causas. A lesão pulmonar ocorre por efeito direto sobre as células epiteliais pulmonares ou em decorrência de efeito indireto sobre as células endoteliais, onde o dano pulmonar decorre da liberação de mediadores inflamatórios em órgãos distais. Neste artigo, enfatizamos as diferenças microscópicas e submicroscópicas no pulmão envolvido na LPA e SDRA, ambas caracterizadas por intensa resposta inflamatória local com acúmulo de diferentes tipos celulares.O remodelamento do parênquima pulmonar caracterizado por fibroelastogênese ocorre em paralelo com o processo inflamatório. O prognóstico do paciente dependerá da resolução do evento inicial e do balanço entre a intensidade das respostas inflamatória e de remodelamento. Diferentes protocolos tentam modificar ambas as respostas, mas todos com resultados negativos. Postulamos que, para uma melhor compreensão da fisiopatologia da SDRA, diferenças microscópicas e submicroscópicas devem ser consideradas. Logo, para se estabelecer uma conduta clínica mais precisa e melhorar o prognóstico desses pacientes, deve-se considerar a etiologia da LPA/SDRA.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) can be induced by various causes. Lung injury can occur through direct or indirect effects on the lung epithelial cells, the latter caused by the release of inflammatory mediators in distal organs. In this article, we emphasize the lung microscopy and ultrastructural changes seen in ALI and ARDS, both of which are characterized by an intense inflammatory process with cell infiltration. The lung parenchyma remodeling process is characterized by fibroelastogenesis occurring in parallel with the inflammatory process. The prognosis depends on the resolution of the initial event and on the balance between the inflammatory response and the remodeling process. Although various protocols have been developed in attempts to modify those aspects, none have produced positive results.We postulate that a better understanding of ARDS cannot be gained without taking lung microscopy and ultrastructural analysis of the lung parenchyma into account. Therefore, in order to improve the clinical management and the prognosis of patients with ALI/ARDS, the etiology of the syndrome should be considered.

Como determinar a volemia em pacientes com lesão pulmonar aguda/síndrome do desconforto respiratório agudo / Determining blood volume in patients with acute lung injury/acute respiratory distress syndrome

A morbidade e a mortalidade de pacientes com lesão pulmonar aguda (LPA) ou síndrome do desconforto respiratório agudo (SDRA) permanecem elevadas. Devido às alterações na membrana alvéolo-capilar, assim como uma possível elevação da pressão hidrostática, a reposição volêmica passa a ter extrema importância. Para tal, são necessárias avaliações precisas do estado volêmico e da predição da resposta hemodinâmica.Estudos recentes enfatizam a indução de um balanço negativo em pacientes com LPA que não se encontram em choque circulatório. Novos estudos têm focado em alternativas menos invasivas e mais precisas na abordagem de fluidos em pacientes com LPA/SDRA. Nesse contexto, recentes estudos têm demonstrado a superioridade de parâmetros dinâmicos sobre parâmetros estáticos na responsividade de fluidos. Além disso, parâmetros que forneçam informações importantes de pré-carga cardíaca e do grau de edema pulmonar têm sido enfatizados por alguns ensaios clínicos de pequeno porte.Indica-se a restrição de fluidos em pacientes com LPA/SDRA desde que não haja choque circulatório. Nessa situação, considera-se o uso de parâmetros dinâmicos para determinar a quantidade e o tipo de fluido administrados. Para a determinação de edema pulmonar, lança-se mão da medida da água extravascular pulmonar, sabendo de suas potencialidades e limitações.

The morbidity and mortality remain elevated in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Hemodynamic stabilization in such patients may require fluid resuscitation, but the increase in hydrostatic pressure may worsen lung edema in presence of increased permeability of the alveolar-capillary membrane. Therefore, accurate evaluation of the fluid state and prediction of the hemodynamic response are essential. Recent studies have focused on the induction of a negative fluid balance in ALI patients who are not in circulatory shock. Other studies of ALI/ARDS patients have focused on fluid management strategies that are less invasive and more accurate. In this context, recent studies have demonstrated the superiority of dynamic parameters over static parameters in determining the hemodynamic response. In addition, parameters that furnish useful data regarding cardiac preload and the degree of pulmonary edema have been emphasized in recent small clinical trials. In ALI/ARDS patients, fluid restriction is indicated if there are no clinical signs of circulatory shock. In such cases, the nature and quantity of fluid administered should be determined on the basis of the dynamic parameters. To screen for pulmonary edema, extravascular lung water can be measured, assuming that its potential and limitations are borne in mind.

Biopsy-proven pulmonary determinants of heart disease.

Heart disease (HD) can stress the alveolar blood-gas barrier, resulting in parenchymal inflammation and remodeling. Patients with HD may therefore display any of the symptoms commonly attributed to primary pulmonary disease, although tissue documentation of corresponding changes through surgical lung biopsy (SLB) is rarely done. Intent on exploring the basis of HD-related alveolar-capillary barrier dysfunction, a retrospective analysis of SLB histopathology was conducted in patients with clinically diagnosed HD, diffuse pulmonary infiltrates, and no evidence of primary pulmonary disease. Patients eligible for the study had a clinical diagnosis of heart disease, acute or chronic, and presented with diffuse infiltrates on chest X-ray. All qualified subjects (N = 23) who underwent diagnostic SLB between January 1982 and December 2005 were subsequently examined. Specific biopsy parameters investigated included demonstrable edema, siderophage influx, hemorrhage, venous and lymphatic ectasia, vascular sclerosis, capillary congestion, and fibroblast proliferation. Based on observed alveolar-capillary barrier (ACB) alterations, three main morphologic groups emerged: one group (6 patients) with alveolar edema; a second group (11 patients) characterized by pulmonary congestion; and a final group (6 patients) showing microscopic foci of acute ACB lung injury. Alveolar-capillary stress due to acute high-pressure or volume overload often manifests as diffuse pulmonary infiltrates with variable but generally predictable histopathology. In patients with biopsy-proven alveolar edema, pulmonary congestion, or acute microscopic lung injury, the clinician must be alert for the possibility of primary heart disease, particularly if the patient is elderly or when a history of myocardial, valvular, or coronary vascular disease exists.

A simple method for the differential characterization of alveoli and alveolar ducts in injured lungs.

RATIONALE AND HYPOTHESIS: Previous studies evaluating the histoarchitecture of distal airspaces have been shown to be limited by the difficulty in adequately differentiating alveoli and alveolar ducts. This limitation has been specially noticed in studies addressing lung recruitment and in situations of diffuse alveolar damage (DAD), where generic nominations for distal airspaces had to be created, such as "peripheral airspaces" (PAS) and "large-volume gas-exchanging airspaces" (LVGEA). Elastic stains have been largely used to describe normal lung structures. Weigert's resorcin-fuchsin staining (WRF) demarcates the thickened free portions of the ductal septum facilitating its recognition. We hypothesized that this staining could help in differentiating alveoli from alveolar ducts in distorted lung parenchyma. MATERIAL AND METHODS: Samples of control lungs and of DAD lungs induced by mechanical ventilation (VILI) were stained with hematoxylin-eosin (HE) and with WRF. Using morphometry we assessed the volume proportion of alveoli, alveolar ducts and LVGEA in control and VILI lungs. RESULTS: WRF stained VILI lungs showed a significant decrease in the volume proportion of LVGEA and alveoli and a significant increase in the volume proportion of alveolar ducts when compared to HE stained samples. CONCLUSION: We conclude that WRF staining is useful to distinguish alveolar ducts from alveoli in a DAD model, and suggest that it should be routinely used when morphometric studies of lung parenchyma are performed.

[Alveolar epithelial barrier in patients with acute respiratory distress syndrome (ARDS)]. / La barrera epitelial alveolar en el enfermo con síndrome de dificultad respiratoria aguda (SDRA).

The clearance of alveolar fluid depends on the anatomic and physiologic integrity of alveolar epithelial barrier. The vectorial transport of sodium begins at the apical surface in the type II cell through amiloride-sensitive sodium channel. Sodium is pumping by Na, K-ATPasa from the basolateral surface of type II cell to the interstice. Water passes through specialized channels in the type I cell membrane by the osmotic gradient created by sodium. The activity of the sodium transporters is regulated actively by genetics and depends on molecular processes that involve the hormonal stimulation. The damage to the epithelial membrane produces an increased of the permeability of great molecules, which favors generation of edema in the alveolar space, delay in the resolution and incapacity to regenerate epithelium. More clinic trials are required to demonstrate the paper of the transport of chloride and to clarify the true function of the specialized water channels in the regulation of the alveolar fluid clearance.

Utilidad de la medición de permeabilidad alveolocapilar con TC99m-DTPA en el compromiso pulmonar de pacientes portadores del virus de inmunodeficiencia adquirida / Value of Tc99m-DTPA alveolar permeability in lung involvement detection of patients with HIV infection

Se evaluó la utilidad de la medición de permeabilidad alveolocapilar con Tc99m -DTPA en pacientes VIH positivo con posible compromiso pulmonar e infección por pneumocystis carinii (PC) . Se incluyeron 20 pacientes con síntomas respiratorios y 4 con síntomas sistémicos usando como control a un grupo de 11 asintomáticos con similar valor de linfocitos CD, todos con suspensión de tabaco previa. Se realizaron radiografía de tórax, hemograma, esputo inducido y/o fibrobroncoscopía, obteniéndose confirmación de presencia o ausencia de PC en 16 pacientes sintomáticos y 3 asintomáticos. Para detección de PC la sensibilidad fue 78 por ciento, la especificidad 40 por ciento y la seguridad diagnóstica 58 por ciento. Para procesos inflamatorios pulmonares los valores fueron 85 por ciento, 60 por ciento y 79 por ciento, respectivamente. Cuatro de seis pacientes falsos positivos para PC tenían cuadros que explicaban la alteración del DTPA. Concluyendo, el DTPA es sensible pero poco específico para detectar infección pulmonar por PC, siendo superior para procesos inflamatorios

Daño pulmonar con amiodarona y su seguimiento con la prueba de permeabilidad alvéolo-capilar con T c99m-DTPA: comunicación en dos casos / Pulmonary damage due to amiodarone and it follow up through alveolar-capillary permeability test: report of 2 cases

La amiodarona es una potente droga antiarrítmica de importante uso en nuestro medio, caracterizada por su prolongada vida media de eliminación. Se le ha descrito una reacción adversa pulmonar que se manifiesta como una enfermedad difusa, intersticial y/o alveolar, con una incidencia promedio de 5 a 7 por ciento de los casos. Esta alveolitis presenta una importante complejidad diagnóstica, tanto por la multiplicidad de diagnósticos diferenciales, como por la ausencia de una prueba específica y precoz. Se presentan dos casos de alveolitis por amiodarona cuyo diagnóstico y seguimiento se realizó con la prueba de Tc99m-DTPA. Esta prueba resultó significativamente disminuida (menos del 50 por ciento del valor normal) en el momento del diagnóstico y se mantuvo anormalmente baja por tiempo prolongado a pesar del tratamiento esteroidal. Se discuten algunos aspectos de esta prueba radioisotópica y sus alcances diagnósticos y de seguimiento en el daño pulmonar unducido por amiodarona

Efectos de la contaminación atmosférica sobre la permeabilidad alvéolo-capilar usando Tc99m DTPA / Effects of air pollution on alveolar-capillary permeability using 99mTc-DTPA

Es un hecho conocido que diversas condiciones pueden afectar la permeabilidad alvéolo-capilar (PAC) tales como algunas enfermedades inflamatorias activas (neumonitis, síndrome de "distress" respiratorio del adulto, membrana hialina, sarcoidosis, asbestosis, infección por neumocistis carinii y otras infecciones) y también el tabaco y el ozono. En esta revisión se analizan algunos métodos capaces de evaluar la integridad de la PAC; difusión de O2 y CO, lavado broncoalveolar, Gn 67 y tomografía axial computarizada de cortes delgados. Otra prueba no invasiva es la medición de la difusión del Tc99m-DTPA. Corresponde a una molécula pequeña, hidrosoluble (490 Dalton) la cual si es inhalada desde el micronebulizador puede depositarse en la parte distal del árbol broncoalveolar, siendo posible entonces medir su difusión al lecho capilar sanguíneo. La exposición experimental de animales a contaminantes atmosféricos altera la permeabilidad traqueal y broncoalveolar y también lo hace la exposición a O3. Santiago de Chile es una de las ciudades de mayor contaminación atmosférica, especialmente en su área central. Se comunica un trabajo preliminar acerca del efecto del smog sobre la salud de jóvenes voluntarios durante el invierno (período de mayor smog) comparando en área central de Santiago con una zona semirural no contaminada. Hubo diferencias significativas entre ambos grupos. El grupo de Santiago fue también estudiado en verano, encontrándose una diferencia estacional significativa. Con los hechos expuestos queda abierta una forma fácil de evaluar no invasivamente la población expuesta a contaminantes atmosféricos