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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of various natural hydrophobic lipids on the in vitro and in vivo activity of human leukocyte elastase has been examined. In vitro studies using 2 different substrates indicated that fatty acids inhibit human leukocyte elastase activity, with maximum inhibition observed with oleic acid. Triolein, cholesterol, and beta-carotene caused little inhibition. The presence of a carboxyl group appears important since retinoic acid but not retinol also inhibited activity. In vivo studies of an emphysema model in mice indicated that intrapulmonary instillation of oleic or retinoic acid reduced lung injury caused by human leukocyte elastase. The possibility of using these compounds to diminish elastolytic damage in emphysema is raised.
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PMID:Inhibition of the activity of human leukocyte elastase by lipids particularly oleic acid and retinoic acid. 212 21

This study compared the oxygen cost of breathing (VO2 resp) in 19 patients with severe chronic obstructive pulmonary disease intubated for acute respiratory failure. Ten patients showed radiologic (X-ray and/or computed tomographic scan) evidence of emphysema. The remaining ones were considered as having chronic bronchitis. Measurements were made just before extubation. Despite similar expiratory airflow obstruction, patients with emphysema exhibited significantly higher VO2 resp than patients with chronic bronchitis (109 +/- 61 versus 42 +/- 26 ml/min/m2, respectively; p < 0.006). Moreover, emphysema was associated with nutritional depletion assessed through decreases in body mass index (emphysema: 17.9 +/- 3.5 kg/m2; chronic bronchitis: 28.8 +/- 8.2 kg/m2; p < 0.005). This seemed to affect somatic stores (significant decreases in arm muscular circumference and triceps skin-fold thickness, whereas visceral stores were preserved (no decreases in serum albumin, serum prealbumin, and retinol binding protein). Malnutrition appeared to be the consequence of a hypermetabolic state of the respiratory muscles, with a significant negative correlation between VO2 resp and body mass index, arm muscular circumference, and triceps skinfold thickness (p < 0.05). Total oxygen consumption normalized for body surface was similar in the two groups. Thus, in emphysematous patients, the oxygen available for tissues other than respiratory muscles was significantly reduced (emphysema: 124 +/- 51 ml/min/m2; chronic bronchitis: 207 +/- 78 ml/min/m2; p < 0.02). This could explain nutritional differences observed between patients with emphysema and those with chronic bronchitis.
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PMID:Oxygen cost of breathing in patients with emphysema or chronic bronchitis in acute respiratory failure. 866 67

The mechanisms by which exposure to cigarette smoke dramatically increase the incidence and severity of atherosclerosis and the incidence of lung cancer, chronic obstructive airways disease, and emphysema are incompletely understood. Epidemiologic evidence has suggested a modifying role for antioxidant micronutrients, including tocopherols and carotenoids, in these disease processes. It has been suggested that oxidants in cigarette smoke could be involved. We exposed freshly obtained human plasma to the gas phase of cigarette smoke to assess its effects on tocopherols, carotenoids, and retinol. Exposure to cigarette smoke led to the depletion of most of the lipophilic antioxidants in 20 mL human plasma. The order of disappearance was lycopene > alpha-tocopherol > trans-beta-carotene++ > (lutein + zeaxanthin) = cryptoxanthin > gamma-tocopherol = retinol. However, despite a substantial loss of alpha-tocopherol, there was very little peroxidative damage to lipids, and no detectable change in the content of polyunsaturated fatty acid-rich cholesterol esters. We conclude that a wide spectrum of lipophilic micronutrients undergo degradation when exposed to gas-phase cigarette smoke. The relevance of these in vitro findings to possible cigarette smoke-induced depletions of respiratory tract lipophilic antioxidants remains to be clarified.
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PMID:Destruction of tocopherols, carotenoids, and retinol in human plasma by cigarette smoke. 859 20

We showed previously that vitamin A deficiency per se causes emphysema. Benzo(a)pyrene, a constituent in cigarette smoke, induces vitamin A depletion when administered to rats; therefore, we tested the hypothesis that cigarette smoke induces vitamin A depletion, which is associated with the development of emphysema. Male weanling rats were fed a purified AIN-93G diet and divided into two groups. The experimental group was exposed to cigarette smoke from 20 nonfiltered commercial cigarettes/d for 5 d/wk, whereas the control group was exposed to air. After 6 wk, tissues were collected for histological and biochemical analyses. Retinol levels were measured in serum, lung and liver. The trachea, lung and liver were examined for histological changes. Vitamin A levels decreased significantly in serum, lung and liver of smoke-treated rats. Histological examination revealed the presence of interstitial pneumonitis along with severe emphysema. There was a significant inverse relationship between vitamin A concentration in the lung and the severity of emphysema (r = -0.69 and P < 0.03). Detachment or hyperplasia (and metaplasia) of the tracheal epithelium and liver vacuole formation also were evident in the smoke-treated rats. The results of this research indicate that exposure to cigarette smoke induces vitamin A depletion in rats, which is associated with the development of emphysema.
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PMID:Vitamin A depletion induced by cigarette smoke is associated with the development of emphysema in rats. 1288 49

Recent data suggest that exogenous retinoic acid (RA), the biologically active derivative of vitamin A, can induce alveolar regeneration in a rat model of experimental emphysema. Here, we describe a mouse model of disrupted alveolar development using dexamethasone administered postnatally. We show that the effects of dexamethasone are concentration dependent, dose dependent, long lasting and result in a severe loss of alveolar surface area. When RA is administered to these animals as adults, lung architecture and the surface area per unit of body weight are completely restored to normal. This remarkable effect may be because RA is required during normal alveolar development and administering RA re-awakens gene cascades used during development. We provide evidence that RA is required during alveologenesis in the mouse by showing that the levels of the retinoid binding proteins, the RA receptors and two RA synthesizing enzymes peak postnatally. Furthermore, an inhibitor of RA synthesis, disulphiram, disrupts alveologenesis. We also show that RA is required throughout life for the maintenance of lung alveoli because when rats are deprived of dietary retinol they lose alveoli and show the features of emphysema. Alveolar regeneration with RA may therefore be an important novel therapeutic approach to the treatment of respiratory diseases characterized by a reduced gas-exchanging surface area such as bronchopulmonary dysplasia and emphysema for which there are currently no treatments.
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PMID:Retinoic acid in alveolar development, maintenance and regeneration. 1529 8

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation. Cigarette smoke has been considered a major player in the pathogenesis of COPD. The inflamed airways of COPD patients contain several inflammatory cells. Vitamin A metabolites have been implicated in the repair of lung damage. Exposure to cigarette smoke has been shown to depress levels of retinol in lungs of rats. The purpose of this study was to investigate if a low, but not deficient, vitamin A status potentiated susceptibility to the development of cigarette smoke-induced lung emphysema in mice. Mice were bred that were the offspring's of 3 generations of mice that were fed a purified diet containing low levels of vitamin A and exposed to cigarette smoke for 3 months, every weekday. Then, levels of 9-cis, 13-cis, and all-trans retinoic acid, retinol and retinyl palmitate were measured in plasma, liver and right lung lobe. The left lung lobe was used to assess mean linear intercept (Lm), as a measure of smoke-induced lung damage. Average feed intakes were not different between treatment groups. We show that both retinol and retinyl palmitate levels were dramatically decreased in the storage organs of mice on the low vitamin A diet (retinol 2-fold in both lung and liver, and retinyl palmitate 5- fold in lung) which shows that the depletion was successful. However, this treatment did not result in the development of lung emphysema. However, smoke exposure led to a significant increase in Lm in mice with a low vitamin A status compared to the room air-breathing controls. Lung levels of acid retinoids were similar in all mice, irrespective of diet or smoke exposure. Concluding, a low vitamin A status increases the susceptibility to the development of cigarette smoke-induced lung emphysema, possibly because of decreased anti-oxidant capacity in the lungs due to locally reduced retinol and retinyl palmitate levels. These observations indicate that human populations with a low vitamin A status and a high prevalence of smoking may be at increased risk of developing lung emphysema.
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PMID:A low vitamin A status increases the susceptibility to cigarette smoke-induced lung emphysema in C57BL/6J mice. 2167 65

Chronic obstructive pulmonary disease (COPD) comprising of emphysema and chronic bronchitis are the most common chronic respiratory diseases that impart a huge economic and clinical burden. Factors other than smoking and air pollutants can cause inflammation and emphysematous changes in the lung airspaces or alveoli have been understudied. Using a cross-sectional study design, we assessed the association of dark green vegetables, vitamin K and Vitamin A with emphysema status among adults at U.S. These nutrients have a role in lung biology. A complete case NHANES data (n = 17,681) was used. After adjusting for modifiable and non-modifiable confounders, consumption of recommended amounts of vitamin K was associated with 39% decrease in odds (Odds Ratio: 0.61; 95% CI: 0.40-0.92, P-val: 0.02) of emphysema. Similarly consumption of recommended amounts vitamin A dose was associated with 33% decrease in odds (Odds Ratio: 0.67; 95% CI: 0.44-1.00, P-val: 0.05) of emphysema. Vitamin K shows an inverse association suggesting that it may be important in slowing the emphysematous process. Vitamin A is important in maintaining the anti-inflammatory process. Together vitamin K and vitamin A are important in the lung health.
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PMID:Consumption of Vitamin K and Vitamin A Are Associated With Reduced Risk of Developing Emphysema: NHANES 2007-2016. 3239 72