Experimental lung research
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Chronic obstructive pulmonary disease (COPD) is characterized by pulmonary and extrapulmonary manifestations including systemic inflammation and weight loss. Increased levels of interleukin-6 (IL-6) have been demonstrated in sputum and serum of COPD patients. Therefore, the authors investigated the in vivo role of IL-6 in a murine model of COPD. ⋯ Chonic CS exposure was associated with a significant failure to gain weight in both WT mice and IL-6 KO mice. Remarkably, air-exposed IL-6 KO mice have lower body weight, serum leptin levels, and adipose tissue mass compared to air-exposed WT mice. In conclusion, IL-6 is of minor importance in CS-induced pulmonary and systemic manifestations in mice, but this study confirms the role for IL-6 as regulator of body weight and body composition.
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High tidal volume mechanical ventilation can cause inflammation and lung damage. Mechanical strain is also necessary for normal lung growth. The current work was performed to determine if mechanical ventilation with clinically utilized tidal volumes stimulates a proliferative response in the lung. ⋯ Dual staining confirmed that proliferating cells labeled with proSP-B, demonstrating that ventilation induces proliferation of alveolar type II cells. Ventilation did not increase apoptosis in alveolar type II cells, as measured by TUNEL staining. Ventilation at low tidal volumes leads to a mild inflammatory response and alveolar epithelial cell proliferation.
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Comparative Study
Observation of ventilation-induced Spo(2) oscillations in pigs: first step to noninvasive detection of cyclic recruitment of atelectasis?
High arterial partial oxygen pressure (Pao(2)) oscillations within the respiratory cycle were described recently in experimental acute lung injury. This phenomenon has been related to cyclic recruitment of atelectasis and varying pulmonary shunt fractions. Noninvasive detection of Spo(2) (oxygen saturation measured by pulse oximetry) as an indicator of cyclic collapse of atelectasis, instead of recording Pao(2) oscillations, could be of clinical interest in critical care. ⋯ Peripheral hemoglobin saturation was capable to capture changes of Spo(2) within each respiratory cycle. For the first time, Spo(2) oscillations due to cyclic recruitment of atelectasis within a respiratory cycle were determined by photoplethysmography, a technology that can be readily applied noninvasively in clinical routine. A mathematic model to calculate the respective Pao(2) changes was developed and its applicability tested.
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Studies demonstrated that pathophysiological abnormalities of airway smooth muscle (ASM) contribute significantly to chronic obstructive pulmonary disease (COPD) pathogenesis, the aim of this study is to investigate heat shock protein 70 (Hsp70) in ASM in COPD. ASM from 8 COPD patients and 6 controls were isolated for detection of Hsp70 using Western blot. Male adult Wister rats were exposed to mixture of cigarette smoke/air or room air for an indicated period. ⋯ In addition, 3-month exposure to cigarette smoke/air mixture resulted in significantly lower Hsp70 and Hsf1 in rats ASM than 1-month exposure (P <.001), and it was a positive correlation of Hsf1 and Hsp70. Long-term cigarette smoking results in reduced expression of Hsp70 in ASM. This finding provides additional insight in understanding molecular changes in ASM during COPD pathogenesis.
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The authors devised a novel bronchial artery catheterization technique to deliver agents directly into bronchial circulation with preserved blood flow in an awake ovine model. A polyurethane catheter was inserted into bronchial artery via an incision into the 4th intercostal space. Regional blood flow of the airway was measured by fluorescent microspheres before cannulation, after cannulation, and 7 days after the operative procedure. ⋯ The regional blood flow increased 10-fold after inhalation injury in bronchi of the sham group. Bronchial artery ligation significantly attenuated the increase of blood flow. However, cannulation preserved regional blood flow and did not prevent the blood flow increases after burn and smoke inhalation injury, thus constituting a novel bronchial artery catheterization technique.