Mainstream and sidestream cigarette smoke exposure increases retinol in guinea pig lungs

Desensitization of beta-adrenergic receptors in lung injury induced by 2-chloroethyl ethyl sulfide, a mustard analog

2-Choloroethyl Ethyl Sulfide (CEES) exposure causes inflammatory lung diseases, including acute respiratory distress syndrome (ARDS) and pulmonary fibrosis. This may be associated with oxidative stress, which has been implicated in the desensitization of beta-adrenergic receptors (beta-ARs). The objective of this study was to investigate whether lung injury induced by intratracheal CEES exposure (2 mg/kg body weight) causes desensitization of beta-ARs. The animals were sacrificed after 7 days and lungs were removed. Lung injury was established by measuring the leakage of iodinated-bovine serum albumin ([(125)I]-BSA) into lung tissue. Receptor-binding characteristics were determined by measuring the binding of [(3)H] dihydroalprenolol ([(3)H] DHA) (0.5-24 nM) to membrane fraction in the presence and absence of DLDL-propranolol (10 micro M). Both high- and low-affinity beta-ARs were identified in the lung. Binding capacity was significantly higher in low-affinity site in both control and experimental groups. Although CEES exposure did not change K(D) and B(max) at the high-affinity site, it significantly decreased both K(D) and B(max) at low affinity sites. A 20% decrease in beta(2)-AR mRNA level and a 60% decrease in membrane protein levels were observed in the experimental group. Furthermore, there was significantly less stimulation of adenylate cyclase activity by both cholera toxin and isoproterenol in the experimental group in comparison to the control group. Treatment of lungs with 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterase (PDE) could not abolish the difference between the control group and the experimental group on the stimulation of the adenylate cyclase activity. Thus, our study indicates that CEES-induced lung injury is associated with desensitization of beta(2)-AR.

Vitamin A and emphysema

Within the last several years, research scientists and clinicians have been intrigued with the potential use of an active form of vitamin A, retinoic acid (RA), for the treatment and prevention of emphysema. The interest in this area can be largely attributed to the work of Massaro and Massaro (1996, 1997, 2000) in which they presented evidence that RA partially protects against and to some degree restores elastase-induced emphysema in rats. The mechanism for this protective effect of RA is in part related to elastin metabolism. RA also inhibits inflammation, an upstream event that may lead to the development of emphysema. Although there is evidence of this protective effect in young rats and a mechanistic explanation, more studies are needed in humans in order to establish a role for vitamin A in protecting against emphysema. Too many unanswered questions remain to definitively state that vitamin A protects against this disease in humans. Nevertheless, the potential for this novel approach in prevention and treatment of emphysema is an exciting area of research.

Harmful health effects of cigarette smoking

This is a comprehensive review on the harmful health effects of cigarette smoking. Tobacco smoking is a reprehensible habit that has spread all over the world as an epidemic. It reduces the life expectancy among smokers. It increases overall medical costs and contributes to the loss of productivity during the life span. Smoking has been shown to be linked with various neurological, cardiovascular, and pulmonary diseases. Cigarette smoke not only affects the smokers but also contributes to the health problems of the non-smokers. Exposure to environmental tobacco smoke contributes to health problems in children and is a significant risk factor for asthma. Cigarette smoke contains several carcinogens that alter biochemical defense systems leading to lung cancer.

Vitamin A depletion induced by cigarette smoke is associated with the development of emphysema in rats

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.

Increased respiratory symptoms following surgery in children exposed to environmental tobacco smoke

OBJECTIVE

The aim of this study was to determine if children exposed to environmental tobacco smoke (ETS) via parental smoking (ETS+) developed more respiratory symptoms resulting in longer recovery times following surgical outpatient procedures compared with children of nonsmoking parents (ETS-).

METHODS

One hundred and forty six children (4.9 +/- 3 years) undergoing inguinal hernia repair were prospectively studied. Parental smoking behaviour was determined by survey and urine analysis. Seven respiratory symptoms were evaluated during induction and emergence from anaesthesia and during the recovery room (RR) stay.

RESULTS

Fifty-seven (39%) families admitted a smoking history while 89 (61%) denied it. This strongly correlated with the cotinine/creatinine ratio (Pearson correlation coefficient = 0.76; P = 0.01). ETS exposure was associated with an increased frequency of RR symptoms (ETS+: 56%; ETS-: 31%; P = 0.007).

CONCLUSIONS

In children undergoing general anaesthesia for inguinal hernia repair, ETS exposure was associated with an increased frequency of respiratory symptoms during emergence from anaesthesia and during postoperative recovery.

Epigallocatechin gallate, a potential immunomodulatory agent of tea components, diminishes cigarette smoke condensate-induced suppression of anti-Legionella pneumophila activity and cytokine responses of alveolar macrophages

Even though cigarette smoking has been shown to suppress immune responses in the lungs, little is known about the effect of cigarette smoke components on respiratory infections. In the present study, the effects of cigarette smoke condensate (CSC) on bacterial replication in alveolar macrophages and the immune responses of macrophages to infection were examined. Furthermore, a possible immunotherapeutic effect of epigallocatechin gallate (EGCg), a major form of tea catechins, on the CSC-induced suppression of antimicrobial activity and immune responses of alveolar macrophages was also determined. The treatment of murine alveolar macrophage cell line (MH-S) cells with CSC significantly enhanced the replication of Legionella pneumophila in macrophages and selectively down-regulated the production of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) induced by bacterial infection. The treatment of macrophages with EGCg not only overcame the CSC-induced suppression of antimicrobial activity but also strengthened the resistance of macrophages to infection. EGCg also markedly up-regulated the CSC-suppressed IL-6 and TNF-alpha production by macrophages in response to infection. The results of exogenous TNF-alpha treatment and neutralization treatment with anti-TNF-alpha and anti-gamma-interferon (IFN-gamma) antibodies and the determination of IFN-gamma mRNA levels indicate that CSC-suppressed macrophages can be activated by EGCg to inhibit L. pneumophila growth by up-regulation of TNF-alpha and IFN-gamma production. Thus, this study revealed that CSC selectively alters the immune responses of macrophages to L. pneumophila infection and leads to an enhancement of bacterial replication in macrophages. In addition, the tea catechin EGCg can diminish such suppressive effects of CSC on alveolar macrophages.

Mainstream and sidestream cigarette smoke exposure increases Ca2+-dependent phospholipid binding proteins in guinea pig alveolar type II cells

We have earlier identified the presence of a 36 kDa Ca2+-dependent phospholipid-binding protein (PLBP) in guinea pig alveolar type II cells. PLBP has been suggested to act as a mediator in facilitating and regulating intracellular surfactant assembly and delivery to the plasma membrane of type II cells for secretion into alveolar space. It has been reported that cigarette smoke exposure (CSE) causes a decrease in the surfactant activity in bronchial washings. We have also reported earlier that mainstream (MS) and sidestream (SS) CSE causes desensitization of beta-adrenoreceptors in guinea pig alveolar type II cells. Since both Ca2+ and beta-adrenoreceptors are involved in surfactant secretion and PLBP is involved in surfactant delivery, it is important to know whether CSE causes any change in the PLBP level in alveolar type II cells. In the present study, we have demonstrated that MS and SS CSE causes a significant increase in the levels of PLBP in alveolar type II cells (107 and 150%, respectively) and in lung lavage (42 and 125%, respectively) in comparison to that in sham control (430 ng/mg protein in alveolar type II cells and 780 ng/mg protein in lung lavage). The mechanism by which smoke exposure causes an elevation in the levels of PLBP in alveolar type II cells and lung lavage remains to be investigated.