Clark Lantz
Work Summary
We are interested in the effects of early life exposures to environmental toxicants on lung growth and development. We determine if the early life exposures leads to adult disease.
We are interested in the effects of early life exposures to environmental toxicants on lung growth and development. We determine if the early life exposures leads to adult disease.
To examine the hypothesis that Jet Propulsion Fuel (JP-8) inhalation potentiates influenza virus-induced inflammatory responses, we randomly divided female C57BL/6 mice (4-weeks old, weighing approximately 24.6g) into the following groups: air control, JP-8 alone (1023 mg/m(3) of JP-8 for 1h/day for 7 days), A/Hong Kong/8/68 influenza virus (HKV) alone (a 10 microl aliquot of 2000 viral titer in the nasal passages), and a combination of JP-8 with HKV (JP-8 + HKV). The HKV alone group exhibited significantly increased total cell number/granulocyte differential in bronchoalveolar lavage fluid (BALF) compared to controls whereas the JP-8 alone group did not. The JP-8 + HKV group further exacerbated the HKV alone-induced response. However, increases in pulmonary microvascular permeability and pathological alterations in JP-8 + HKV just matched the sum of JP-8 alone- and HKV alone-induced response. Increases in BALF substance P in the JP-8 alone group and BALF leukotriene B4 or total lung compliance in the HKV alone group, respectively were similar to the changes in the JP-8 + HKV group. These findings suggest that changes in the JP-8 + HKV group may be attributed to either JP-8 inhalation or HKV treatment and indicate the different physiological responses to either JP-8 or HKV exposure. Taken together, most of the data did not provide supporting evidence that JP-8 inhalation synergizes influenza virus-induced inflammatory responses.
To characterize the tachykininergic effects in fire smoke (FS)-induced acute respiratory distress syndrome (ARDS), we designed a series of studies in rats. Initially, 20 min of FS inhalation induced a significant increase of substance P (SP) in bronchoalveolar lavage fluid (BALF) at 1 h and persisted for 24 h after insult. Conversely, FS disrupted 51.4, 55.6, 46.3, and 43.0% enzymatic activity of neutral endopeptidase (NEP, a primary hydrolyzing enzyme for SP) 1, 6, 12, and 24 h after insult, respectively. Immunolabeling density of NEP in the airway epithelium largely disappeared 1 h after insult due to acute cell damage and shedding. These changes were also accompanied by extensive influx of albumin and granulocytes/lymphocytes in BALF. Furthermore, levels of BALF SP and tissue NEP activity dose dependently increased and decreased, respectively, following 0, low (10 min), and high (20 min) levels of FS inhalation. However, neither the time-course nor the dose-response study observed a significant change in the highest affinity neurokinin-1 receptor (NK-1R) for SP. Finally, treatment (10 mg/kg im) with SR-140333B, an NK-1R antagonist, significantly prevented 20-min FS-induced hypoxemia and pulmonary edema 24 h after insult. Further examination indicated that SR-140333B (1.0 or 10.0 mg/kg im) fully abolished early (1 h) plasma extravasation following FS. Collectively, these findings suggest that a combination of sustained SP and NEP inactivity induces an exaggerated neurogenic inflammation mediated by NK-1R, which may lead to an uncontrolled influx of protein-rich edema fluid and cells into the alveoli as a consequence of increased vascular permeability.