Cyr Voisin

Abnormal Secretion of Interleukin-1 and Tumor Necrosis Factor α by Alveolar Macrophages in Coal Worker's Pneumoconiosis: Comparison between Simple Pneumoconiosis and Progressive Massive Fibrosis

The aim of this study was to compare the secretion of tumor necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) by alveolar macrophages (AMs) harvested from patients with coal workers pneumoconiosis (CWP) and control subjects. We observed higher levels of spontaneous TNF alpha and IL-1 secretion by AMs from patients with CWP than in those from healthy controls. We did not find any significant difference between the two groups in the incidence of simple pneumoconiosis and progressive massive fibrosis. In the group of coal miners without radiologic signs of pneumoconiosis, we found high levels of both cytokines in a subgroup of subjects still exposed to the mineral dust but not in the subgroup of subjects removed from exposure. These results indicate that AMs are involved in chronic lung inflammatory reactions to mineral dusts, partly by way of cytokine secretion. Moreover, cytokine secretion by AMs appears to be an early event that is detectable at the moment of mineral dust exposure. The results open new perspectives in the study of the mechanisms leading to CWP.

In vitro acute effects of tobacco smoke on tumor necrosis factor alpha and interleukin-6 production by alveolar macrophages.

Tobacco smoke is a usual form of oxidant aggression present in the domestic environment. In the present study, the in vitro acute effects of a 2-cigarette smoke gas phase were evaluated on cell viability and cytokine secretion by alveolar macrophages (AM) from guinea pigs and human healthy subjects. Cell injury was estimated immediately after smoke exposure by evaluation of ATP cell content (measured by bioluminescence) and lactic dehydrogenase (LDH) release in the culture medium. LDH release was also measured when the interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF) activities were evaluated. No cytotoxic effect was found: The ATP cell content of both guinea pig AM and human AM did not significantly change after tobacco smoke exposure. Similarly, the LDH release in the culture medium was unchanged both immediately after tobacco smoke exposure and at the time of the cytokine evaluation (18-20 h later) compared to cells cultured in the air. The total protein synthesis by the guinea pig AM evaluated by 35S-L-methionine labeling was unaffected by tobacco smoke exposure. The production of IL-6 and TNF activities was evaluated 18-20 h after smoke exposure. The IL-6 activity was measured by the proliferation test of 7TD1 hybridoma cell line; the TNF activity was evaluated by the L929 mouse fibroblast cytotoxic test and by an immunoradiometric assay (for human AM). A 2-cigarette smoke exposure decreased both activities significantly. The exposure of the guinea pig AM reduced IL-6 activity by 24.3 +/- 6.7%, 42.4 +/- 7.8%, and 39.7 +/- 9.6% and TNF activity by 33.8 +/- 10.4%, 35.1 +/- 10.7%, and 38.8 +/- 9.9% (respectively unstimulated cells and AM activated by 0.1 and 10 micrograms LPS/mL). The decrease in monokine production by the human AM was, respectively, 57.8 +/- 8.8%, 59.7 +/- 11.4%, and 49.9 +/- 10.5% of IL-6 activity and 37.4 +/- 14.6%, 17.6 +/- 9.6%, and 37.2 +/- 6.3% of TNF activity. The possible release of cytokine inhibitors was also investigated. The inhibitory activity against recombinant TNF and IL-6 was evaluated in culture medium from unstimulated AM exposed to tobacco smoke and did not significantly differ from that of AM exposed to air, demonstrating that the decrease of monokine levels could not be explained by the release of inhibitory factors.(ABSTRACT TRUNCATED AT 400 WORDS)

In Vitro Effects of Hyperoxia on Alveolar Type II Pneumocytes: Inhibition of Glutathione Synthesis Increases Hyperoxic Cell Injury

An in vitro model of alveolar epithelial oxidant injury was developed based on exposure to hyperoxia of cultured guinea pig type II pneumocytes using a biphasic cell culture system in aerobiosis. The present study investigates the roles of intracellular antioxidant enzymes and of glutathione in providing protection against hyperoxia. A 2-day type II cell culture in normoxia was associated with a significant decrease in protein, catalase, and Cu-Zn SOD cell content, whereas ATP cell content, Mn-SOD, and glutathione peroxidase (GPx) activities did not change and glutathione cell content significantly increased. Exposure of type II cells to hyperoxia did not induce significant changes in cell content in protein, SOD, catalase, GPx, or glutathione cell content when compared to control cells (exposed to normoxia). With ATP cell content expressed as a cell injury index (CII), type II cell injury was found to increase with increasing O2 concentrations. Indeed, a 2-day 50% O2 and 95% O2 exposure resulted in a CII of -7.5 +/- 6.2% and 17.9 +/- 5.9%, respectively, LDH release by type II cells was not significantly increased after hypoxic exposure. Cell injury effects of hyperoxia did not correlate with the endogenous antioxidant enzyme activities (SOD, Mn-SOD, catalase). In marked contrast, there was a significant correlation between the CII and total glutathione content of type II cells (p < .01). This correlation was largely due to the close relationship between CII and reduced glutathione. Hyperoxic induced cell injury (as demonstrated by CII > 0) was clearly associated with significantly lower intracellular glutathione level when compared to experiments without hyperoxia induced cell injury (CII < 0). In addition, in the presence of buthionine sulfoximine (BSO), the ability of type II cells to synthetize new glutathione was severely impaired, whereas ATP cell content and cell antioxidant enzyme activities did not change. As a consequence, the reduction of intracellular glutathione significantly increased the susceptibility of cells to hyperoxia injury (p < .05). The results strongly support the hypothesis that the regulation of glutathione levels is an important mechanism in protecting hyperoxia-induced type II cell injury.

Activated alveolar macrophage and lymphocyte alveolitis in extrathoracic sarcoidosis without radiological mediastinopulmonary involvement

Cellular characteristics of BAL were investigated in 18 patients with proved extrathoracic sarcoidosis (that is, sarcoidosis that affected the skin, eyes, parotid glands, stomach, nose, kidneys, or meninges) without clinical or radiological mediastinopulmonary involvement. Computed tomography of the thorax was performed on five patients: four patients were normal, and one had enlarged lymph nodes (these enlargements were not detectable on the patients chest roentgenogram). The results of pulmonary function tests were normal in all patients. The total BAL cell count did not differ significantly between controls and patients. Abnormal percentages of alveolar lymphocytes (from 18 to 87%) were noted in 15 out of 18 patients. SACE levels were normal in 15 patients. No pulmonary gallium uptake was detected. The chemiluminescence of AMs, whether spontaneous or PMA induced, was increased in five out of seven patients. The percentages of T3+ lymphocytes in sarcoidosis patients did not significantly differ from those in controls. The T4+:T8+ ratio was normal in four patients and slightly increased in one. Follow-up of patients showed that alveolar lymphocytosis is as lasting as extrathoracic involvement. Our data demonstrate increased percentages of lymphocytes and activated AMs in the BAL of patients with extrathoracic sarcoidosis. This may be due to the initial involvement of the respiratory tract in extrathoracic sarcoidosis or to the diffusion of activated macrophages and lymphocytes from an extrathoracic site into the lung.

Release of superoxide anion by alveolar macrophages in pulmonary sarcoidosis.

Biological mechanisms involving nonprotease factors mediate the alterations of the alveolar structures which lead to the interstitial fibrosis of pulmonary sarcoidosis. Thus, we have investigated the production of oxidant species by BAL cells from 50 sarcoidosis patients and 18 healthy controls using a lucigenin-dependent CL method. Spontaneous and PMA-induced CLs were significantly higher in untreated patients and treated patients than in spontaneously cured patients or healthy controls (p less than .05). SOD inhibits 60 to 75% of spontaneous CL and 91 to 93% of PMA-induced CL. There was no apparent correlation between the CL of AMs and the radiological types, SACE levels, and gallium scans. In marked contrast, CL was significantly higher in patients with increased alveolar lymphocytosis (greater than or equal to 18%) than in patients with normal BAL. Since there were neither neutrophils nor eosinophils in BAL and since lymphocytes do not produce lucigenin-dependent CL, we believe that CL is produced by AMs. CL inhibition by SOD suggests that superoxide anion is involved in the production of CL. The release of both superoxide anion and related radicals may be of importance in the pathogenesis of pulmonary sarcoidosis.

Alveolar Macrophages Secretory Dysfunctions in Coal Workers’s Pneumoconiosis. Comparison Between Simple Pneumoconiosis and Progressive Massive Fibrosis.

Coal worker’s pneumoconiosis (CWP) comprises a variety of pulmonary radiological and pathological changes resulting from the inhalation of coal dust. Coal worker’s pneumoconiosis is usually divided in two groups: simple pneumoconiosis (SP) and progressive massive fibrosis (PMF). This distinction is of importance in clinical practice since PMF is definitively disabling. However, why some workers should develop PMF when exposed to dust concentrations similar to those experimencied by workers who develop only SP is unknown. Current concepts emphazise the role of alveolar macrophages in the pathogenesis of chronic interstitial lung diseases (Voisin, 1983; Davis, 1986). In this way, the cells recovered by bronchoalveolar lavage were extensively used to evaluate the distribution of cell type and the secretory activities of alveolar macrophages that could be relevant to the pathogenesis of CWP, such as superoxide anion, neutrophil chemotactic factors, fibronectin (Wallaert, 1986). Here we have extended our study on macrophage secretory dysfunctions by the measurement of interleukin-1 and tumor necrosis factor alpha spontaneously released by alveolar macrophages.

Broncho Alveolar Lavage in Coal Worker’s Pneumoconiosis: Oxidant and Antioxidant Activities of Alveolar Macrophages

Recent studies identified disturbances in the alveolar macrophage (AM) population harvested by broncho alveolar lavage (BAL) in patients with coal worker’s pneumoconiosis (CWP) or silicosis (Si): increased number of recovered cells (Voisin 1983), normal cellular viability and phagocytic activity when evaluated immediately after BAL procedure (Schluyer 1980), but impaired after 24 h of in vitro culture (Voisin 1983), and release of fibroblast growth factors: fibronectin and alveolar macrophage derived growth factor (Rom 1984). The aim of this work is to study the possible alterations of the oxidant-antioxidant system of AM due to the presence of intracytoplasmic mineral particles.

Evaluation of Proinflammatory Cytokine Expression in Alveolar Macrophages and in the Lung of Pneumoconiotic Patients

In order to confirm their in vivo participation in the pathogenesis of Coal Workers’ Pneumoconiosis (CWP), TNF and IL-6 secretion and expression were evaluated in bronchoalveolar lavage (BAL) and lung tissue from pneumoconiotic patients. BAL was collected from 19 simple pneumoconiosis (SP) and 8 progressive massive fibrosis (PMF), while lung parenchyma specimen were obtained from 1 SP and 3 PMF. TNF and IL-6 mRNA expression was assessed using in situ hybridization. To identify the cellular source of these monokines, immunocytochemistry was performed on lung tissue. TNF and IL-6 concentrations were quantified using bioassay. In situ hybridization was performed using 35S-labelled RNA probes encoding for TNF and IL-6.

Controlled in Vitro Approach of Low Concentration NO2. Effects on Human Alveolar Macrophage Functions

The lung is the target of multiple aggressions due to occupational hazards, environmental noxious substances and personnal risks such as tobacco smoke. In all of these situations, alveolar macrophages (AM) located on the respiratory membrane, are in close and permanent contact with the airbone pollutants and are directly exposed to particles and toxic gases. Thus, taking into account the multiple functional activities of this cell population (6), it seems reasonable to hypothezise that alveolar macrophages play a pivotal role in the responses of the respiratory tract to the inhaled materials.