The Civil Liberty of Smoking Cigarettes

E-cigarette use increases susceptibility to bacterial infection by impairment of human neutrophil chemotaxis, phagocytosis, and NET formation

E-cigarettes are portrayed as safer relative to conventional tobacco. However, burgeoning evidence suggests that E-cigarettes may adversely affect host defenses. However, the precise mechanisms by which E-cigarette vapor alters innate immune cell function have not been fully elucidated. We determined the effects of E-cigarette exposure on the function and responses to infectious challenge of the most abundant innate immune cell, the neutrophil, using isolated human neutrophils and a mouse model of gram-negative infection. Our results revealed that human neutrophils exposed to E-cigarette vapor had 4.2-fold reductions in chemotaxis toward the bacterial cell-well component f-Met-Leu-Phe (P < 0.001). F-actin polarization and membrane fluidity were also adversely affected by E-cigarette vapor exposure. E-cigarette-exposed human neutrophils exhibited a 48% reduction in production of reactive oxygen species (ROS; P < 0.001). Given the central role of ROS in neutrophil extracellular trap (NET) production, NET production was quantified, and E-cigarette vapor exposure was found to reduce NETosis by 3.5-fold (P < 0.01); formulations with and without nicotine containing propylene glycol exhibiting significant suppressive effects. However, noncanonical NETosis was unaffected. In addition, exposure to E-cigarette vapor lowered the rate of phagocytosis of bacterial bioparticles by 47% (P < 0.05). In our physiological mouse model of chronic E-cigarette exposure and sepsis, E-cigarette vapor inhalation led to reduced neutrophil migration in infected spaces and a higher burden of Pseudomonas. These findings provide evidence that E-cigarette use adversely impacts the innate immune system and may place E-cigarette users at higher risk for dysregulated inflammatory responses and invasive bacterial infections.

Cigarette smoking causes epigenetic changes associated with cardiorenal fibrosis

Clinical studies indicate that smoking combustible cigarettes promotes progression of renal and cardiac injury, leading to functional decline in the setting of chronic kidney disease (CKD). However, basic studies using in vivo small animal models that mimic clinical pathology of CKD are lacking. To address this issue, we evaluated renal and cardiac injury progression and functional changes induced by 4 wk of daily combustible cigarette smoke exposure in the 5/6th partial nephrectomy (PNx) CKD model. Molecular evaluations revealed that cigarette smoke significantly (P < 0.05) decreased renal and cardiac expression of the antifibrotic microRNA miR-29b-3 and increased expression of molecular fibrosis markers. In terms of cardiac and renal organ structure and function, exposure to cigarette smoke led to significantly increased systolic blood pressure, cardiac hypertrophy, cardiac and renal fibrosis, and decreased renal function. These data indicate that decreased expression of miR-29b-3p is a novel mechanism wherein cigarette smoke promotes accelerated cardiac and renal tissue injury in CKD. (155 words).

Inflammatory Diseases of the Lung Induced by Conventional Cigarette Smoke: A Review

Smoking-induced lung diseases were extremely rare prior to the 20th century. With commercialization and introduction of machine-made cigarettes, worldwide use skyrocketed and several new pulmonary diseases have been recognized. The majority of pulmonary diseases caused by cigarette smoke (CS) are inflammatory in origin. Airway epithelial cells and alveolar macrophages have altered inflammatory signaling in response to CS, which leads to recruitment of lymphocytes, eosinophils, neutrophils, and mast cells to the lungs-depending on the signaling pathway (nuclear factor-κB, adenosine monophosphate-activated protein kinase, c-Jun N-terminal kinase, p38, and signal transducer and activator of transcription 3) activated. Multiple proteins are upregulated and secreted in response to CS exposure, and many of these have immunomodulatory activities that contribute to disease pathogenesis. In particular, metalloproteases 9 and 12, surfactant protein D, antimicrobial peptides (LL-37 and human β defensin 2), and IL-1, IL-6, IL-8, and IL-17 have been found in higher quantities in the lungs of smokers with ongoing inflammation. However, many underlying mechanisms of smoking-induced inflammatory diseases are not yet known. We review here the known cellular and molecular mechanisms of CS-induced diseases, including COPD, respiratory bronchiolitis-interstitial lung disease, desquamative interstitial pneumonia, acute eosinophilic pneumonia, chronic rhinosinusitis, pulmonary Langerhans cell histiocytosis, and chronic bacterial infections. We also discuss inflammation induced by secondhand and thirdhand smoke exposure and the pulmonary diseases that result. New targeted antiinflammatory therapeutic options are currently under investigation and hopefully will yield promising results for the treatment of these highly prevalent smoking-induced diseases.