Effect of nicotine on the immune system: possible regulation of immune responses by central and peripheral mechanisms

Neuroimmune communication of the cholinergic system in gut inflammation and autoimmunity

Neuroimmune communication in the body forms a bridge between two central regulatory systems of the body, i.e., nervous and immune systems. The cholinergic system is a crucial modulatory neurotransmitter in the central and peripheral nervous system. It includes the neurotransmitter acetylcholine (ACh), the enzyme required for the synthesis of ACh (choline acetyltransferase, ChAT), the enzyme required for its degradation (acetylcholinesterase, AChE), and cholinergic receptors (Nicotinic acetylcholine receptors and muscarinic acetylcholine receptors). The cholinergic system in neurons is well known for its role in cognitive function, sensory perception, motor control, learning, and memory processes. It has been shown that the non-neuronal cholinergic system (NNCS) is present in various tissues and immune cells and forms a neuroimmune communications system. In the present review, we discussed the NNCS on immune cells, its role in homeostasis and inflammatory reactions in the gut, and how it can be exploited in treating inflammatory responses.

Inflammatory profile of apical periodontitis exacerbated by cigarette smoke inhalation: Histological and immunohistochemical analysis in rats

AIM

The aim of this study was to evaluate the effects of cigarette smoke inhalation (CSI) on inflammation, pro-inflammatory mediators and haematological parameters in rats with induced apical periodontitis (AP).

METHODOLOGY

Thirty-two 3-month-old male Wistar rats were divided into four experimental groups (n = 8): C-Control; S-rats with CSI; AP-rats with AP; and SAP-rats with CSI + AP. Animals in groups S and SAP inhaled cigarette smoke by remaining inside a smoking chamber for 8 min, three times daily, for 50 days. After 20 days of smoke inhalation, animals in AP and SAP groups had the pulps of the lower right first molar exposed to oral environment for 30 days to induce AP. In these subsequent 30 days, animals in group S and SAP continued with CSI. On Day 50, animals were euthanized and mandibles were histologically processed to assess inflammatory infiltrate, immunohistochemical interleukins (IL-1β, IL-6 and TNF-α), and blood samples collected for laboratory analysis. The Mann-Whitney test was performed for non-parametric data and the pairwise analyses of Student's t-test for parametric data, with a significance level of p < .050.

RESULTS

Inflammatory infiltrate was moderate in AP group and more severe in the SAP (p = .010). The interleukins IL-6, IL-1β and TNF-α were higher in SAP group (p < .001) when compared to the AP group. A greater number of red blood cells (p = .010), haemoglobin (p = .007) and neutrophils (p = .014) were observed in the SAP group in comparison with the AP group.

CONCLUSION

Cigarette smoke inhalation induced a more severe inflammatory infiltrate, with increased levels of pro-inflammatory cytokines and changes in haematological parameters in rats with induced AP. Thus, CSI aggravated AP, exacerbating the inflammatory response.

Analgesic potential of transdermal nicotine patch in surgery: a systematic review and meta-analysis of randomised placebo-controlled trials

OBJECTIVES

We aimed (1) to systematically review the efficacy of transdermal nicotine patches (NP) for postoperative analgesia, (2) to establish the current quality of evidence and assist clinical decision-making on the subject, and (3) to identify methodological limitations and the need for more well-designed studies.

MATERIALS AND METHODS

We searched six electronic databases, protocol records, and other sources without date or language restriction until March 2022. To develop the search strategy, we formulated a clinical question by using the PICOD method. Eligibility criteria included randomised placebo-controlled trials on the analgesic potential of NP for surgical procedures. This systematic review followed the PRISMA 2020 statement, and we registered the protocol in PROSPERO (#CRD42020205956).

RESULTS

We included 10 randomised placebo-controlled trials (535 patients). The NP administered before induction of anaesthesia and at beginning of surgery reduced the pain immediately after surgery (-0.38; 95% confidence interval [CI]: -0.73 to -0.02), and 6 h (-0.34; 95% CI: -0.68 to -0.01), 12 h (-0.43; 95% CI: -0.71 to -0.15) and 24 h (-0.35; 95%CI: -0.59 to -0.10) after surgery, compared with the placebo patch (PP) group. Sensitivity testing suggests that opioid use could underestimate NP analgesia. Late demand for the first analgesic and consumption of rescue analgesics tended to be lower in the NP group.

CONCLUSIONS

The current findings suggest, with low certainty of evidence, the analgesic potential of NP for surgical procedures.

CLINICAL RELEVANCE

Perioperative use of NP significantly improved postoperative pain, even when opioids were administered or prescribed. Nevertheless, the clinical relevance should be interpreted with caution, owing to the effect sizes of the summary measures and methodological issues. The analgesic potential of NP as an adjuvant therapy to regulate pain and acute inflammation may offer certain clinical advantages, thus warranting further investigation.

Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches

Sarcoidosis is a systemic granulomatous inflammatory disease of unknown etiology. It affects the lungs in over 90% of patients yet extra-pulmonary and multi-organ involvement is common. Spontaneous remission of disease occurs commonly, nonetheless, over 50% of patients will require treatment and up to 30% of patients will develop a chronic progressive non-remitting disease with marked pulmonary fibrosis leading to significant morbidity and death. Guidelines outlining an immunosuppressive treatment approach to sarcoidosis were recently published, however, the strength of evidence behind many of the guideline recommended drugs is weak. None of the drugs currently used for the treatment of sarcoidosis have been rigorously studied and prescription of these drugs is often based on off-label” indications informed by experience with other diseases. Indeed, only two medications [prednisone and repository corticotropin (RCI) injection] currently used in the treatment of sarcoidosis are approved by the United States Food and Drug Administration. This situation results in significant reimbursement challenges especially for the more advanced (and often more effective) drugs that are favored for severe and refractory forms of disease causing an over-reliance on corticosteroids known to be associated with significant dose and duration dependent toxicities. This past decade has seen a renewed interest in developing new drugs and exploring novel therapeutic pathways for the treatment of sarcoidosis. Several of these trials are active randomized controlled trials (RCTs) designed to recruit relatively large numbers of patients with a goal to determine the safety, efficacy, and tolerability of these new molecules and therapeutic approaches. While it is an exciting time, it is also necessary to exercise caution. Resources including research dollars and most importantly, patient populations available for trials are limited and thus necessitate that several of the challenges facing drug trials and drug development in sarcoidosis are addressed. This will ensure that currently available resources are judiciously utilized. Our paper reviews the ongoing and anticipated drug trials in sarcoidosis and addresses the challenges facing these and future trials. We also review several recently completed trials and draw lessons that should be applied in future.

Anti-inflammatory activity of Nicotine isolated from Brassica oleracea in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease, associated with chronic inflammation of synoviocytes. TNFα plays a crucial role in the pathogenesis of RA through pro-inflammatory cytokines. Nicotine, an alkaloid used as herbal medicine, often worked as an anti-inflammatory agent. In this study, we tried to uncover the anti-inflammatory impact of nicotine against RA. Nicotine was isolated from Brassica oleracea, purified by high profile liquid chromatography (HPLC). In-silico docking was carried out using bioinformatics tools SWISSADME, PASS, and DIGEP-Pred to determine drug likeliness of nicotine. The In-vitro study was performed in Tumor necrosis factor (TNFα) induced SW982 Synoviocytes by qPCR.  mRNA expression of pro-inflammatory cytokines (TNF, IL6, IL1β) and proteins (TRAF2, P50, P65) were analyzed followed by validation of P65 (RELA), pP65, IkBα by western blot analysis. Nicotine compound was extracted from Brassica oleracea and purified by HPLC method (Rt values at 2.67 min). The physicochemical, pharmacokinetic properties and drug-likeliness of nicotine was studied by in-silico analysis. In-vitro studies revealed that nicotine lowers the expression of inflammatory cytokines (TNF, IL6, IL1β) and proteins (TRAF2, P50, P65) at 1 µg/ml in TNFα induced SW982 cells.Nicotine from natural sources (Brassica oleracea) has been found to be an effective anti- inflammatory compound at a low dosage. Thus identified the role of nicotine present in the natural sources as a therapeutic option for RA, may be recommended as remedial drug instead of synthetic drug.

Tobacco use disorder and the lungs

This narrative review provides a summary of the impact of tobacco smoking on the respiratory system and the benefits of smoking cessation. Tobacco smoking is one of the leading preventable causes of death world-wide and a major risk factor for lung cancer and chronic obstructive pulmonary disease. Smoking is also associated with an increased risk of respiratory infections and appears to be related to poorer outcomes among those with COVID-19. Non-smokers with second-hand smoke exposure also experience significant adverse respiratory effects. Smoking imposes enormous health- and non-health-related costs to societies. The benefits of smoking cessation, in both prevention and management of respiratory disease, have been known for decades and, to this day, cessation support remains one of the most important cost-effective interventions that health professionals can provide to people who smoke. Cessation at any age confers substantial health benefits, even in smokers with established morbidities. As other treatments for chronic respiratory disease advance and survival rates increase, smoking cessation treatment will become even more relevant. While smoking cessation interventions are available, the offer of these by clinicians and uptake by patients remain limited.

Association of sociodemographic and environmental factors with spatial distribution of tuberculosis cases in Gombak, Selangor, Malaysia

Tuberculosis (TB) cases have increased drastically over the last two decades and it remains as one of the deadliest infectious diseases in Malaysia. This cross-sectional study aimed to establish the spatial distribution of TB cases and its association with the sociodemographic and environmental factors in the Gombak district. The sociodemographic data of 3325 TB cases such as age, gender, race, nationality, country of origin, educational level, employment status, health care worker status, income status, residency, and smoking status from 1st January 2013 to 31st December 2017 in Gombak district were collected from the MyTB web and Tuberculosis Information System (TBIS) database at the Gombak District Health Office and Rawang Health Clinic. Environmental data consisting of air pollution such as air quality index (AQI), carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and particulate matter 10 (PM10,) were obtained from the Department of Environment Malaysia from 1st July 2012 to 31st December 2017; whereas weather data such as rainfall were obtained from the Department of Irrigation and Drainage Malaysia and relative humidity, temperature, wind speed, and atmospheric pressure were obtained from the Malaysia Meteorological Department in the same period. Global Moran's I, kernel density estimation, Getis-Ord Gi* statistics, and heat maps were applied to identify the spatial pattern of TB cases. Ordinary least squares (OLS) and geographically weighted regression (GWR) models were used to determine the spatial association of sociodemographic and environmental factors with the TB cases. Spatial autocorrelation analysis indicated that the cases was clustered (p<0.05) over the five-year period and year 2016 and 2017 while random pattern (p>0.05) was observed from year 2013 to 2015. Kernel density estimation identified the high-density regions while Getis-Ord Gi* statistics observed hotspot locations, whereby consistently located in the southwestern part of the study area. This could be attributed to the overcrowding of inmates in the Sungai Buloh prison located there. Sociodemographic factors such as gender, nationality, employment status, health care worker status, income status, residency, and smoking status as well as; environmental factors such as AQI (lag 1), CO (lag 2), NO2 (lag 2), SO2 (lag 1), PM10 (lag 5), rainfall (lag 2), relative humidity (lag 4), temperature (lag 2), wind speed (lag 4), and atmospheric pressure (lag 6) were associated with TB cases (p<0.05). The GWR model based on the environmental factors i.e. GWR2 was the best model to determine the spatial distribution of TB cases based on the highest R2 value i.e. 0.98. The maps of estimated local coefficients in GWR models confirmed that the effects of sociodemographic and environmental factors on TB cases spatially varied. This study highlighted the importance of spatial analysis to identify areas with a high TB burden based on its associated factors, which further helps in improving targeted surveillance.

Predicting related factors of immunological response to hepatitis B vaccine in hemodialysis patients based on integration of decision tree classification and logistic regression

The non/hypo-response rate of the hepatitis B vaccine among hemodialysis (HD) patients is still high, it is of great significance to explore the influencing factors and their relationships. To study the related factors and their relationships using logistic regression model and Chi-squared Automatic Interaction Detection (CHAID) decision tree model. A randomized controlled trial was conducted between February 2014 and May 2015 in China. HD patients being serologically negative for HBsAg and anti-HBs were randomly assigned to receive three intramuscular injections of the standard dose (20 µg) or high dose (60 µg) of recombinant hepatitis B vaccine at months 0, 1, and 6. Those with anti-HBs concentrations <100 mIU/mL, and ≥100 mIU/mL at month 7 were considered as non/hypo-response and high-level response, respectively. The non/hypo-response was 31.34% (89/284). After adjustment for confounders, logistic analysis showed that males (OR = 2.203, 95%CI: 1.109-4.367) and those with higher dialysis frequency (>4 times per 2 weeks) (OR = 1.918, 95%CI: 1.015-3.626) had a significant risk of non/hypo-response. While the CHAID analysis showed that gender, dose, and dialysis frequency were influencing factors of non/hypo-response, and gender is most important. The interaction between gender and dialysis frequency had the greatest effect on immunization, and followed by the interaction between dialysis frequency and vaccine dose. Taken together, gender, dose and dialysis frequency were influencing factors of hepatitis B vaccine in HD patients.

Cholinergic System and Its Therapeutic Importance in Inflammation and Autoimmunity

Neurological and immunological signals constitute an extensive regulatory network in our body that maintains physiology and homeostasis. The cholinergic system plays a significant role in neuroimmune communication, transmitting information regarding the peripheral immune status to the central nervous system (CNS) and vice versa. The cholinergic system includes the neurotransmitter\ molecule, acetylcholine (ACh), cholinergic receptors (AChRs), choline acetyltransferase (ChAT) enzyme, and acetylcholinesterase (AChE) enzyme. These molecules are involved in regulating immune response and playing a crucial role in maintaining homeostasis. Most innate and adaptive immune cells respond to neuronal inputs by releasing or expressing these molecules on their surfaces. Dysregulation of this neuroimmune communication may lead to several inflammatory and autoimmune diseases. Several agonists, antagonists, and inhibitors have been developed to target the cholinergic system to control inflammation in different tissues. This review discusses how various molecules of the neuronal and non-neuronal cholinergic system (NNCS) interact with the immune cells. What are the agonists and antagonists that alter the cholinergic system, and how are these molecules modulate inflammation and immunity. Understanding the various functions of pharmacological molecules could help in designing better strategies to control inflammation and autoimmunity.

The Association Between E-Cigarette Use Behaviors and Saliva Cotinine Concentration Among Healthy E-Cigarette Users in Malaysia

Electronic cigarettes (e-cigarettes) have rapidly increased in popularity within the last 2 years in Malaysia. The study aims to understand the association between e-cigarette use behaviors and salivary cotinine (a CYP2AA metabolite of nicotine) concentration to inform the development of future e-cigarette control policies. A convenience sample of saliva from 144 e-cigarette users was obtained between November and December 2015. The study participants used refill liquid containing between 0 and 12 mg/ml of nicotine. The overall median cotinine concentration of the study participants was 81.1 ng/ml (interquartile range = 8.5-195.8). Among the zero-nicotine and single e-cigarette users, the median cotinine level was 51.1 (interquartile range = 8.20-125.35) ng/ml. Factors significantly associated with a higher salivary cotinine concentration were dual use of e-cigarettes and tobacco cigarettes, regular and daily e-cigarette use, a longer duration of e-cigarette use, using a higher amount of e-liquid, and a shorter duration to finish a refill. Multivariate analysis revealed that e-cigarette use of 1-6 and 6-12 months (but not 1 month and below) was significantly associated with a higher cotinine concentration. Cotinine found in zero-nicotine e-liquids implies the importance of stringent regulatory governance for the consistency of labeled nicotine content of e-cigarette liquid in the market. Zero-nicotine e-cigarette users should also be informed of the likelihood of environmental exposure to tobacco smoke. Future studies conducted on larger samples are warranted to validate the association between duration of e-cigarette use and salivary cotinine concentration as well as to investigate underlying mechanisms.

Cigarette Smoke Exposure Inhibits Early Phase of Antibody Production through Inhibition of Immune Functions in Alveolar Macrophage

Background::

Cigarette smoke (CS) is inhaled into the lung. Alveolar macrophage (AM) is known to play an important role in the lung immune system. However, the relationship between AM functions and antibody production by CS is not fully investigated.

Objective::

Therefore, we investigated the effects of AM from CS exposed mice on antibody production. Mice were exposed to 20 cigarettes/day for 10 days. AM were obtained by broncho-alveolar lavage. Antibody production was analyzed by plaque-forming cell assay using seep red blood cell (SRBC) as antigen.

Methods::

B cell proliferation was analyzed by 3H-thymidine incorporation. Phagocytic activity using fluorescein isothiocyanate-labeled SRBC and expressions of surface antigens on AM were analyzed by flow cytometry. Cytokines and NF-κB mRNA expressions of AM were analyzed by RTPCR.

Results and Discussion:

Antibody production was decreased at the induction phase, but not at the expression phase by AM from smoked mice (SM) compared with non-smoked mice (NSM). B cell proliferation was decreased by cigarette extracts dose-dependently. Phagocytic activity of AM was decreased in SM compared with NSM. Expression of surface antigens on AM was decreased in SM compared with NSM. Cytokines or NF-κB mRNA expressions of AM were decreased in SM compared with NSM.

Conclusion::

These results suggest that the inhibition of antibody production by cigarette smoking is caused by the inhibition of phagocytosis and expressions of surface antigens associated with antigen presentation. Such inhibition of AM functions may increase the risk of bacterial and virus infections.

Viral Respiratory Infections: An Ounce of Prevention Is Worth a Pound of Cure

The sudden outbreak and global spread of COVID-19 demanded a tremendous amount of attention for viral respiratory infections (VRIs) in modern times. Evidence accumulated over the past few decades increasingly suggests the importance of recognizing the background and context of lifestyle factors in the prevention of VRIs recurrence. The focus of attention has specifically been on how to optimize respiratory barrier function and immune function during the period of the pandemic outbreak. This viewpoint discusses the impact of a healthy lifestyle on VRIs and demonstrates a practical approach to preventing the occurrence of VRIs based on contemporary evidence.

Biologic and advanced immunomodulating therapeutic options for sarcoidosis: a clinical update

Introduction: Sarcoidosis is a multi-organ disease with a wide range of clinical manifestations and outcomes. A quarter of sarcoidosis patients require long-term treatment for chronic disease. In this group, corticosteroids and cytotoxic agents be insufficient to control diseaseAreas covered: Several biologic agents have been studied for treatment of chronic pulmonary and extra-pulmonary disease. A review of the available literature was performed searching PubMed and an expert opinion regarding specific therapy was developed.Expert opinion: These agents have the potential of treating patients who have progressive disease. Many of these agents have different mechanisms of action, response rates, and toxicity profiles.

Smoking and COVID-19: Similar bronchial ACE2 and TMPRSS2 expression and higher TMPRSS4 expression in current versus never smokers

Uncertainties remain concerning the pathophysiology, epidemiology, and potential therapeutics for COVID-19. Among unsettled controversies is whether tobacco smoking increases or protects from severe COVID-19. Several epidemiological studies reported reduced COVID-19 hospitalizations among smokers, while other studies reported the opposite trend. Some authors assumed that smokers have elevated airway expression of ACE2, the cell recognition site of the SARS-Cov-2 spike protein, but this suggestion remains unverified. We therefore performed data mining of two independent NCBI GEO genome-wide RNA expression files (GSE7894 and GSE994) and report that in both data sets, current smokers and never smokers have, on average, closely similar bronchial epithelial cell mRNA levels of ACE2, as well as TMPRSS2, coding for a serine protease priming SARS-Cov-2 for cell entry, and ADAM17, coding for a protease implicated in ACE2 membrane shedding. In contrast, the expression levels of TMPRSS4, coding for a protease that primes SARS-CoV-2 for cell entry similarly to TMPRSS2, were elevated in bronchial epithelial cells from current smokers compared with never smokers, suggesting that higher bronchial TMPRSS4 levels in smokers might put them at higher SARS-Cov-2 infection risk. The effects of smoking on COVID-19 severity need clarification with larger studies. Additionally, the postulated protective effects of nicotine and nitric oxide, which may presumably reduce the risk of a "cytokine storm" in infected individuals, deserve assessment by controlled clinical trials.

Nicotinic Acetylcholine Receptor Agonists for the Treatment of Alzheimer's Dementia: An Update

A significant portion of the clinical phenotype observed in Alzheimer's disease (AD) occurs through nicotinic acetylcholine receptors (nAChRs). Degeneration of cholinergic neurons, combined with aberrant nAChR expression and activation partially through amyloid-beta peptide (Aβ)-nAChR leads to upregulation of pro-inflammatory pathways and subsequently the progressive cognitive decline of AD. Interestingly, the cholinergic anti-inflammatory pathway is also mediated through nAChR particularly α7 nAChR. Thus, agonists of these receptors will likely exert pro-cognitive benefits through multiple mechanisms including stimulating the cholinergic pathway, modulating inflammation, and buffering the effects of amyloid. Despite this promising theoretical use, trials thus far have been complicated by adverse effects or minimal improvement. This review will provide an update on several pharmacological nAChR agonists tested in clinical trials and reasons that further investigation of nAChR agonists is merited.

IMPLICATIONS

nAChRs have consistently presented a promising theoretical use in the treatment of AD; however, trials thus far have been complicated by adverse effects or minimal improvement. This review will provide an update on several pharmacological nAChR agonists trialed and reasons that further investigation of nAChR agonists is merited.

Modeling drug exposure in rodents using e-cigarettes and other electronic nicotine delivery systems

Smoking tobacco products is the leading cause of preventable death worldwide. Coordinated efforts have successfully reduced tobacco cigarette smoking in the United States; however, electronic cigarettes (e-cigarette) and other electronic nicotine delivery systems (ENDS) recently have replaced traditional cigarettes for many users. While the clinical risks associated with long-term ENDS use remain unclear, advancements in preclinical rodent models will enhance our understanding of their overall health effects. This review examines the peripheral and central effects of ENDS-mediated exposure to nicotine and other drugs of abuse in rodents and evaluates current techniques for implementing ENDS in preclinical research.

Role of Green Chemistry in Antipsychotics' Electrochemical Investigations Using a Nontoxic Modified Sensor in McIlvaine Buffer Solution

A new low-cost green electrochemical sensor based on nontoxic polyethylene glycol (PEG) and silver nanoparticles was used to improve the sensitivity of the carbon paste electrode for the investigation of olanzapine (OLZ) in dosage arrangements and in the existence of its coadministered drug fluoxetine and in the drug formulation. Scanning electron microscopy measurements were carried out to emphasize the morphology of the electrode surface. Cyclic voltammetry and differential pulse voltammetry were used to explore the diffusion and linearity behaviors of OLZ. Impedance spectroscopy measurements were determined to investigate the ac behavior of OLZ and then an ideal electrical circuit was modeled. A linear calibration was obtained from 1.0 × 10^-8 to 1.25 × 10^-4 M. The limit of detection was 1.5 × 10^-9 M, whereas the limit of quantification was 5 × 10^-9 M. The way has been wholly authenticated concerning linearity, precision, accuracy, reproducibility, sensitivity, and selectivity.

Cigarette smoke and nicotine effects on brain proinflammatory responses and behavioral and motor function in HIV-1 transgenic rats

Cognitive impairment in HIV-1 infection is associated with the induction of chronic proinflammatory responses in the brains of infected individuals. The risk of HIV-related cognitive impairment is increased by cigarette smoking, which induces brain inflammation in rodent models. To better understand the role of smoking and the associated immune response on behavioral and motor function in HIV infection, wild-type F344 and HIV-1 transgenic (HIV1Tg) rats were exposed to either smoke from nicotine-containing (regular) cigarettes, smoke from nicotine-free cigarettes, or to nicotine alone. The animals were then tested using the rotarod test (RRT), the novel object recognition test (NORT), and the open field test (OFT). Subsequently, brain frontal cortex from the rats was analyzed for levels of TNF-α, IL-1, and IL-6. On the RRT, impairment was noted for F344 rats exposed to either nicotine-free cigarette smoke or nicotine alone and for F344 and HIV1Tg rats exposed to regular cigarette smoke. Effects from the exposures on the OFT were seen only for HIV1Tg rats, for which function was worse following exposure to regular cigarette smoke as compared to exposure to nicotine alone. Expression levels for all three cytokines were overall higher for HIV1Tg than for F344 rats. For HIV1Tg rats, TNF-α, IL-1, and IL-6 gene expression levels for all exposure groups were higher than for control rats. All F344 rat exposure groups also showed significantly increased TNF-α expression levels. However, for F344 rats, IL-1 expression levels were higher only for rats exposed to nicotine-free and nicotine-containing CS, and no increase in IL-6 gene expression was noted with any of the exposures as compared to controls. These studies, therefore, demonstrate that F344 and HIV1Tg rats show differential behavioral and immune effects from these exposures. These effects may potentially reflect differences in the responsiveness of the various brain regions in the two animal species as well as the result of direct toxicity mediated by the proinflammatory cytokines that are produced by HIV proteins and by other factors that are present in regular cigarette smoke.

The influence of KIR gene presence/absence polymorphisms on the development of periodontal disease in smokers and non-smokers

Introduction

Periodontal diseases are highly prevalent inflammatory, multifactorial diseases. Smoking is one of the most important environmental risk factors for the development and severity of periodontal disease. Killer cell immunoglobulin-like receptors (KIRs) are members of the immunoglobulin (Ig) superfamily and play an essential role in the regulation of NK cell activity, allowing natural killer (NK) cells to sense and respond to human leukocyte antigen (HLA) class I. The aim of this study was to evaluate the influence of KIR gene presence/absence polymorphisms on the development of periodontal disease in smokers and non-smokers.

Material and methods

This study enrolled 400 Caucasian subjects (age range 25-69 years) from the West Pomeranian region of Poland. The subjects were categorized into four subgroups (smoking and non-smoking patients with periodontal disease; smoking and non-smoking subjects without periodontal disease - control subjects).

Results

The differences of KIR gene frequencies between non-smoking patients and non-smoking control subjects as well as smoking patients and control subjects were not statistically significant. In multivariate regression analysis advanced age of patients and smoking were independent factors associated with increased frequency of periodontal disease.

Conclusions

The results of this study suggest that the main factor associated with increased risk of periodontal disease is smoking, whereas KIR presence/absence polymorphism is not a significant factor involved in the pathogenesis of periodontal disease.

Electronic Cigarettes: Their Constituents and Potential Links to Asthma

PURPOSE OF REVIEW

Vaping is gaining popularity in the USA, particularly among teens and young adults. While e-cigs are commonly represented as safer alternatives to tobacco cigarettes, little is known regarding the health effects of their short- or long-term use, especially in individuals with pre-existing respiratory diseases such as asthma. Flavored e-cig liquids (e-liquids) and e-cig aerosols contain airway irritants and toxicants that have been implicated in the pathogenesis and worsening of lung diseases. In this review, we will summarize existing data on potential health effects of components present in e-cig aerosols, such as propylene glycol, vegetable glycerin, nicotine, and flavorings, and discuss their relevance in the context of asthma.

RECENT FINDINGS

Recent survey data indicate that adolescents with asthma had a higher prevalence of current e-cig use (12.4%) compared to their non-asthmatics peers (10.2%) and conveyed positive beliefs about tobacco products, especially e-cigs. Similarly, a study conducted among high school students from Ontario, Canada, indicated a greater likelihood of e-cig use in asthmatics as compared to their non-asthmatic peers. Availability of different flavorings is often cited as the main reason among youth/adolescents for trying e-cigs or switching from cigarettes to e-cigs. Occupational inhalation of some common food-safe flavoring agents is reported to cause occupational asthma and worsen asthmatic symptoms. Moreover, workplace inhalation exposures to the flavoring agent diacetyl have caused irreversible obstructive airway disease in healthy workers. Additionally, recent studies report that thermal decomposition of propylene glycol (PG) and vegetable glycerin (VG), the base constituents of e-liquids, produces reactive carbonyls, including acrolein, formaldehyde, and acetaldehyde, which have known respiratory toxicities. Furthermore, recent nicotine studies in rodents reveal that prenatal nicotine exposures lead to epigenetic reprogramming in the offspring, abnormal lung development, and multigenerational transmission of asthmatic-like symptoms. Comparisons of the toxicity and health effects of e-cigs and conventional cigarettes often focus on toxicants known to be present in cigarette smoke (CS) (i.e., formaldehyde, nitrosamines, etc.), as well as smoking-associated clinical endpoints, such as cancer, bronchitis, and chronic obstructive pulmonary disease (COPD). However, this approach disregards potential toxicity of components unique to flavored e-cigs, such as PG, VG, and the many different flavoring chemicals, which likely induce respiratory effects not usually observed in cigarette smokers.

Passive smoking and influenza-like illness in housewives: A perspective of gene susceptibility

Relation between influenza-like illness (ILI) and passive smoking remains a debate of subject. We aimed to determine an association of passive smoking with ILI risk of housewives in North China, and the modification effects of gene polymorphisms related to the metabolisms of smoking pollutants. We included 379 housewives for a cross-sectional study in Shanxi Province, China, including 118 with ILI frequency of "≥1 times per year" as the case group and 261 with ILI frequency of "<1 time per year" in the past 10 years as the control group. We collected their information on frequencies of passive smoking and ILI by questionnaires, as well as their single nucleotide polymorphisms (SNPs) of genes related to Phase I and Phase II metabolisms of smoking pollutants. Our results revealed a significant Spearman correlation between frequencies of ILI and passive smoking (r = 0.406, p < 0.001). Frequency of passive smoking was associated with an increased risk of ILI with adjusted OR [6.75 (95% confidence interval: 3.98-11.4)]. Dose-response association between the passive smoking and ILI risk was observed with or without adjusting for confounders. Mutant types of rs1041983 (N-acetyltransferase 2 gene, NAT2) had a synergetic effect with passive smoking on ILI frequency, while mutant types of rs1695 (glutathione S-transferase P1 gene, GSTP1) had an antagonistic effect. Overall, our study results supported the hypothesis that passive smoking was positively associated with ILI frequency in housewives and this effect was modified by gene polymorphisms of Phase II metabolism genes (NAT2 and GSTP1).

Chronic nicotine treatment decreases LPS signaling through NF-κB and TLR-4 modulation in the hippocampus

The hippocampus is a brain region that is rich in nicotinic acetylcholine receptors (nAChRs), especially the α7 subtype. The hippocampus is severely affected in disorders that have a neuroinflammatory component, such as Alzheimer's disease, Parkinson's disease, and schizophrenia. Previous studies demonstrated both in vivo and in vitro that nicotine inhibits immunological responses, including those that are triggered by the inflammatory agent lipopolysaccharide (LPS), the endotoxin of Gram-negative bacteria. The present study investigated whether chronically administered nicotine interferes with the nuclear binding of nuclear factor-κB (NF-κB) and the expression of LPS-induced inflammatory response genes. The results indicated that chronic nicotine administration (0.1mg/kg, s.c., 14days) inhibited the LPS-induced nuclear binding of NF-κB and mRNA expression levels of Tnf, Il1b, Nos2, and Tlr4. The presence of both the selective α7 nAChR antagonist methyllycaconitine (MLA; 5.0mg/kg i.p., 14days) and the nonselective nAChR antagonist mecamylamine (Meca; 1.0mg/kg, s.c., 14days) reversed the inhibitory effects of nicotine. These results suggest that the chronic activation of α7- and α_xβ_y-containing nAChRs reduces acute inflammatory responses in the brain.

Smoking and Serum Lipid Profiles in Schizophrenia

Schizophrenia is associated with a high prevalence of cigarette-smoking and abnormal lipid profiles. The purpose of this study was to determine whether the profiles differ between schizophrenic smokers and non-smokers and whether the lipid profiles are related to psychopathological symptoms. Serum lipid profiles were measured in 130 male inpatients with DSM-IV-defined schizophrenia: 104 smokers and 26 non-smokers. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Our results showed that positive PANSS symptoms were fewer in smokers than in non-smokers, while the negative symptoms were fewer in those who smoked more cigarettes. Total protein and globulin levels were significantly lower in the smokers than in the non-smokers. However, there was no significant difference in total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol, apolipoprotein A1, or apolipoprotein B between the smokers and non-smokers. However, the PANSS positive subscale had a significant negative correlation with the HDL-c levels (a protective factor) in the smokers but not in the non-smokers. Our findings suggest that schizophrenic patients who smoke have fewer psychotic symptoms, but contrary to expectation, smoking does not alter lipid profile levels.

Consumption of Substances of Abuse during Pregnancy Increases Consumption in Offspring: Possible Underlying Mechanisms

Correlative human observational studies on substances of abuse have been highly dependent on the use of rodent models to determine the neuronal and molecular mechanisms that control behavioral outcomes. This is particularly true for gestational exposure to non-illicit substances of abuse, such as excessive dietary fat, ethanol, and nicotine, which are commonly consumed in our society. Exposure to these substances during the prenatal period has been shown in offspring to increase their intake of these substances, induce other behavioral changes, and affect neurochemical systems in several brain areas that are known to control behavior. More importantly, emerging studies are linking the function of the immune system to these neurochemicals and ingestion of these abused substances. This review article will summarize the prenatal rodent models used to study developmental changes in offspring caused by prenatal exposure to dietary fat, ethanol, or nicotine. We will discuss the various techniques used for the administration of these substances into rodents and summarize the published outcomes induced by prenatal exposure to these substances. Finally, this review will cover some of the recent evidence for the role of immune factors in causing these behavioral and neuronal changes.

A functional polymorphism in the interleukin-1beta and severity of nicotine dependence in male schizophrenia: a case-control study

Previous studies have shown that the functional 511C/T polymorphism in the IL-1beta-gene may be implicated in the susceptibility for schizophrenia. Moreover, recent studies suggested that IL-1 participates in the progression of lung disease in smokers, which are overrepresented in schizophrenia. We aimed to investigate the possible relationship between the IL-1beta-511C/T polymorphism and smoking behavior in schizophrenia versus healthy controls in a Chinese population. The IL-1beta-511C/T polymorphism was genotyped in 638 male patients with chronic schizophrenia (smoker/never-smoker = 486/152) and 469 male controls (smoker/never-smoker = 243/226). The cigarettes smoked per day, the Heaviness of Smoking Index (HSI) and the Fagerstrom Test for nicotine dependence (FTND) were assessed. Patients were also rated on the Positive and Negative Syndrome Scale (PANSS). The results showed no significant differences in genotype and allele distribution between patients and controls, and between smokers and never-smokers in either the patient or control group. However, in patients, smokers with the C/C genotype had significantly higher HSI (p < 0.005) and FTND (p < 0.05) scores than smokers with the T/T genotype, without significant differences in controls. Furthermore, there was a linear positive correlation between the number of C alleles and the HSI (p < 0.005) in patients. Our findings suggest that the IL-1beta-511C/T polymorphism may not be related to schizophrenia or smoking status in Chinese individuals, but may affect the severity of nicotine dependence among male smokers with schizophrenia.

Harmful effects of nicotine

With the advent of nicotine replacement therapy, the consumption of the nicotine is on the rise. Nicotine is considered to be a safer alternative of tobacco. The IARC monograph has not included nicotine as a carcinogen. However there are various studies which show otherwise. We undertook this review to specifically evaluate the effects of nicotine on the various organ systems. A computer aided search of the Medline and PubMed database was done using a combination of the keywords. All the animal and human studies investigating only the role of nicotine were included. Nicotine poses several health hazards. There is an increased risk of cardiovascular, respiratory, gastrointestinal disorders. There is decreased immune response and it also poses ill impacts on the reproductive health. It affects the cell proliferation, oxidative stress, apoptosis, DNA mutation by various mechanisms which leads to cancer. It also affects the tumor proliferation and metastasis and causes resistance to chemo and radio therapeutic agents. The use of nicotine needs regulation. The sale of nicotine should be under supervision of trained medical personnel.

Tobacco exposure and susceptibility to tuberculosis: is there a smoking gun?

In many regions of the world, there is a great overlap between the prevalence of cigarette smoke exposure and tuberculosis. Despite the large body of epidemiologic evidence that tobacco smoke exposure is associated with increased tuberculosis infection, active disease, severity of disease, and mortality from tuberculosis, these studies cannot distinguish whether the mechanism is principally through direct impairment of anti-tuberculosis immunity by cigarette smoke or due to potential confounders that increase risk for tuberculosis and are commonly associated with smoking--such as poverty, malnutrition, and crowded living conditions. While there are several in vivo murine and in vitro macrophage studies showing cigarette smoke impairs control of tuberculous infection, little is known of the molecular and cellular mechanisms by which this impairment occurs. Herein, we highlight the key findings of these studies. Additionally, we review key immune cells that play critical roles in host-defense or pathogenesis of tuberculosis and generate a hypothesis-driven discussion of the possible mechanisms by which cigarette smoke impairs or enhances their functions, respectively, ultimately resulting in compromised immunity against tuberculosis.

Neutropenia and invasive fungal infection in patients with hematological malignancies treated with chemotherapy: a multicenter, prospective, non-interventional study in China

In this study, we explored the relationship between neutropenia (absolute neutrophil count (ANC) <1,500/mm(3)) and invasive fungal infection (IFI) in Chinese patients who had hematological malignancies treated with chemotherapy. We conducted a multicenter, prospective, non-interventional study of consecutive patients with hematological malignancies undergoing chemotherapy in China and determined clinical characteristics of patients who developed neutropenia and IFI. The results indicated that for the 2,177 neutropenic patients, 88 (4.0 %) were diagnosed with IFI. We found that a high risk of IFI (P<0.05) is associated with male gender, non-remission of the primary disease, use of two or more broad-spectrum antibiotics, treatment with parenteral nutrition, presence of cardiovascular disease, history of IFI, and neutropenia. When the ANC was less than 1,000, 1,000∼500, 500∼100, and <100/mm(3), the incidence of IFI was 0.5, 5.2, 3.9, and 4.7 %, respectively (ANC>1,000/mm(3) versus other groups, P<0.001). When the ANC was less than 1,000, 500, or 100/mm(3) for 10 days or more, the incidence of IFI was 3.2 versus 6.1 % (P=0.0052), 3.5 versus 7.1 % (P=0.0021), and 3.1 versus 10.0 % (P<0.001). When the ANC was less than 100/mm(3), taking antifungal prophylaxis reduced the incidence of IFI (P<0.05). The IFI-attributable mortality rate was 11.7 %. In conclusion, Chinese patients with IFI, severe and prolonged neutropenia increases the incidence of IFI. The incidence of IFI associated with neutropenia was reduced when antifungal prophylaxis was given. IFI was associated with a significantly increased high mortality rate in hematological malignancy patients with neutropenia.

Influenza virus-induced lung inflammation was modulated by cigarette smoke exposure in mice

Although smokers have increased susceptibility and severity of seasonal influenza virus infection, there is no report about the risk of 2009 pandemic H1N1 (pdmH1N1) or avian H9N2 (H9N2/G1) virus infection in smokers. In our study, we used mouse model to investigate the effect of cigarette smoke on pdmH1N1 or H9N2 virus infection. Mice were exposed to cigarette smoke for 21 days and then infected with pdmH1N1 or H9N2 virus. Control mice were exposed to air in parallel. We found that cigarette smoke exposure alone significantly upregulated the lung inflammation. Such prior cigarette smoke exposure significantly reduced the disease severity of subsequent pdmH1N1 or H9N2 virus infection. For pdmH1N1 infection, cigarette smoke exposed mice had significantly lower mortality than the control mice, possibly due to the significantly decreased production of inflammatory cytokines and chemokines. Similarly, after H9N2 infection, cigarette smoke exposed mice displayed significantly less weight loss, which might be attributed to lower cytokines and chemokines production, less macrophages, neutrophils, CD4⁺ and CD8⁺ T cells infiltration and reduced lung damage compared to the control mice. To further investigate the underlying mechanism, we used nicotine to mimic the effect of cigarette smoke both in vitro and in vivo. Pre-treating the primary human macrophages with nicotine for 72 h significantly decreased their expression of cytokines and chemokines after pdmH1N1 or H9N2 infection. The mice subcutaneously and continuously treated with nicotine displayed significantly less weight loss and lower inflammatory response than the control mice upon pdmH1N1 or H9N2 infection. Moreover, α7 nicotinic acetylcholine receptor knockout mice had more body weight loss than wild-type mice after cigarette smoke exposure and H9N2 infection. Our study provided the first evidence that the pathogenicity of both pdmH1N1 and H9N2 viruses was alleviated in cigarette smoke exposed mice, which might partially be attributed to the immunosuppressive effect of nicotine.

Elevated IL-17A levels in early stages of bladder cancer regardless of smoking status

Aim: The interrelation between nicotine and IL-17A in bladder cancer (BC) patients was investigated. Methods: IL-17A in the sera of 121 BC patients who smoked nicotine, 80 nonsmoker BC patients, 29 and 30 age- and sex-matched healthy smokers and nonsmokers were also measured. Results: IL-17A was elevated in smoker and nonsmoker BC patients compared with smoker and nonsmoker controls (p = 0.004 and p = 0.004, respectively). The level of IL-17A in BC patients who smoked both water pipes and cigarettes were the highest (4.35±8.57 pg/ml), followed by BC water pipe users only (1.33±3.122 pg/ml) and cigarette smokers only (0.79±2.26 pg/ml, p = 0.001). IL-17A was elevated in lower stages (I and II) compared with higher stages (III and IV) of the disease (p = 0.013). Conclusion: IL-17A levels are elevated in some BC patients. IL-17A is an important factor in the inflammatory process during tumor progression, either as a defense mechanism or as a tumor-promoting factor.

Risk factors associated with peritoneal-dialysis-related peritonitis

Background. Peritonitis represents a major complication of peritoneal dialysis (PD). The aim of this paper was to systematically collect data on patient-related risk factors for PD-associated peritonitis, to analyze the methodological quality of these studies, and to summarize published evidence on the particular risk factors. Methods. Studies were identified by searches of Pubmed (1990–2012) and assessed for methodological quality by using a modified form of the STROBE criteria. Results. Thirty-five methodologically acceptable studies were identified. The following nonmodifiable risk factors were considered valid and were associated with an increased risk of peritonitis: ethnicity, female gender, chronic lung disease, coronary artery disease, congestive heart failure, cardiovascular disease, hypertension, antihepatitis C virus antibody positivity, diabetes mellitus, lupus nephritis or glomerulonephritis as underlying renal disease, and no residual renal function. We also identified the following modifiable, valid risk factors for peritonitis: malnutrition, overweight, smoking, immunosuppression, no use of oral active vitamin D, psychosocial factors, low socioeconomic status, PD against patient's choice, and haemodialysis as former modality. Discussion. Modifiable and nonmodifiable risk factors analyzed in this paper might serve as a basis to improve patient care in peritoneal dialysis.

Inflammation and oxidative stress induced by cigarette smoke in Lewis rat brains

Exposure to cigarette smoke has been associated with an increased risk of neurological diseases such as stroke, Alzheimer's disease and multiple sclerosis. In these studies, serum and brain sections from Lewis rats or those exposed to cigarette smoke and control rats were examined for evidence of increased inflammation and oxidative stress. Immunocytochemical staining of brain sections from CS-exposed rats showed increased expression of class II MHC and, in ELISA, levels of IFN-gamma and TNF-α were higher than for non-exposed rats. In polymerase chain reaction assays there was increased interferon-gamma, TNF-α, IL-1α, IL-1β, IL-23, IL-6, IL-23, IL-17, IL-10, TGF-β, T-bet and FoxP3 gene expression with CS exposure. There was also markedly elevated MIP-1α/CCL3, less prominent MCP-1/CCL2 and no elevation of SDF-1α gene expression. Analysis of samples from CS-exposed and control rats for anti-oxidant expression showed no significant difference in serum levels of glutathione and, in brain, similar levels of superoxide dismutase and decreased thioredoxin gene expression. In contrast, there was increased brain gene expression for the pro-oxidants iNOS and the NADPH components NOX4, dual oxidase 1 and p22(phox). Nrf2 expression, which is typically triggered as a secondary response to oxidative stress, was also increased in brains from CS-exposed rats with nuclear translocation of this protein from cytoplasm demonstrated in astrocytes in association with increased expression of the aryl hydrocarbon receptor gene, an Nrf2 target. These studies, therefore, demonstrate that CS exposure in these animals can trigger multiple immune and oxidative responses that may have important roles in the pathogenesis of CNS inflammatory neurological diseases.

Nicotine alters the ectonucleotidases activities in lymphocytes: In vitro and in vivo studies

The aim of the present study was to investigate the effects in vivo and in vitro of nicotine, an important immunosuppressive agent, on NTPDase and ADA activities in lymphocytes of adult rats. The following nicotine doses in vivo study were evaluated: 0.0, 0.25 and 1.0mg/kg/day injected subcutaneously in rats for 10days. The activity of the enzymes were significantly decreased with nicotine 0.25 and 1mg/kg which inhibited ATP (22%, 54%), ADP (44%, 30%) hydrolysis and adenosine (43%, 34%) deamination, respectively. The expression of the protein NTPDase in rat lymphocytes was decreased to nicotine 1mg/kg and the lymphocytes count was decreased in both nicotine doses studied. The purine levels measured in serum of the rats treated with nicotine 0.25mg/kg significantly increased to ATP (39%), ADP (39%) and adenosine (303%). The nicotine exposure marker was determinate by level of cotinine level which significantly increased in rats treated with nicotine 0.25 (39%) and 1mg/kg (131%) when compared to rats that received only saline. The second set of study was in vitro assay which the ATP-ADP-adenosine hydrolysis were decreased by nicotine concentrations 1mM (0% - 0% - 16%, respectively), 5mM (42% - 32% - 74%, respectively), 10mM (80% - 27% - 80%, respectively) and 50mM (96% - 49% - 98%, respectively) when compared with the control group. We suggest that alterations in the activities of these enzymes may contribute to the understanding of the mechanisms involved in the suppression of immune response caused by nicotine.

Effects of Active and Passive Smoking on Ear Infections

Otitis media (OM) is one of the most frequent diseases in young children, causing to visit a physician, and also the most common indication for antibiotic prescription. The peak incidence and prevalence of OM is 6 to 18 months of age. In children, second-hand smoke (SHS) exposure is associated with upper and lower respiratory tract infections, such as acute otitis media (AOM), pneumonia, and bronchitis. Despite the overwhelming evidence of the role of SHS exposure on infant health, a very high proportion of children still continue to be exposed. This important relationship between all kinds of smoking and poor health may not be appreciated universally. With this article, we aim to review tobacco smoke exposure and OM connection. How this exposure may cause OM especially in young children? What can be done to prevent and to reduce the harmfull effects of tobacco smoking?

The role of IL-1β in nicotine-induced immunosuppression and neuroimmune communication

Although a number of inflammatory cytokines are increased during sepsis, the clinical trials aimed at down-regulating these mediators have not improved the outcome. These paradoxical results are attributed to loss of the "tolerance" phase that normally follows the proinflammatory response. Chronic nicotine (NT) suppresses both adaptive and innate immune responses, and the effects are partly mediated by the nicotinic acetylcholine receptors in the brain; however, the mechanism of neuroimmune communication is not clear. Here, we present evidence that, in rats and mice, NT initially increases IL-1β in the brain, but the expression is downregulated within 1-2 week of chronic exposure, and the animals become resistant to proinflammatory/pyrogenic stimuli. To examine the relationship between NT, IL-1β, and immunosuppression, we hypothesized that NT induces IL-1β in the brain, and its constant presence produces immunological "tolerance". Indeed, unlike wild-type C57BL/6 mice, chronic NT failed to induce immunosuppression or downregulation of IL-1β expression in IL-1β-receptor knockout mice. Moreover, while acute intracerebroventricular administration of IL-1β in Lewis (LEW) rats activated Fyn and protein tyrosine kinase activities in the spleen, chronic administration of low levels of IL-1β progressively diminished the pyrogenic and T cell proliferative responses of treated animals. Thus, IL-1β may play a critical role in the perception of inflammation by the CNS and the induction of an immunologic "tolerant" state. Moreover, the immunosuppressive effects of NT might be at least partly mediated through its effects on the brain IL-1β. This represents a novel mechanism for neuroimmune communication.

It takes nerves to fight infections: insights on neuro-immune interactions from C. elegans

The innate immune response is evoked as a consequence of interactions between invading foreign infectious agents and host immune cells. A successful innate immune response is pivotal in maintaining the delicate balance between health and disease; an insufficient response results in infection, whereas an excessive response results in prolonged inflammation and tissue damage. Alterations in the state and function of the nervous system influence the immune response. The nervous system regulates innate immune responses through the release of neurotransmitters, neuropeptides and neurohormones. However, many questions related to the molecular and cellular mechanisms involved, the physiological role of the link between the immune and the nervous system, and the biological significance of neuro-immune interactions remain unresolved. The interactions between the nematode Caenorhabditis elegans and its pathogens provide insights into mechanisms of neuroendocrine regulation of immunity and address many outstanding issues related to neuro-immune interactions.

Interaction between cigarette smoking and hepatitis B and C virus infection on the risk of liver cancer: a meta-analysis

INTRODUCTION

Chronic infection with hepatitis B (HBV) and C viruses (HCV) as well as cigarette smoking are established risk factors of hepatocellular carcinoma (HCC), but it is unclear whether an interaction exists between these factors in causing hepatocellular carcinogenesis. We conducted a meta-analysis to evaluate the interaction of HBV and HCV infection and cigarette smoking on the risk of HCC.

METHODS

We systematically searched the PUBMED and the China National Knowledge Infrastructure databases. A total of 16 eligible publications were identified. Cigarette smoking and chronic HBV and HCV infections were dichotomized into present or absent. Additive (S) and multiplicative interaction indexes (V) between smoking and each of the two infections and their 95% confidence intervals (95% CI) were calculated for each study and then combined in a meta-analysis.

RESULTS

We found a more than additive interaction between HBV infection and cigarette smoking (S=1.44; 95% CI, 1.00-2.06; nine studies) and a more than multiplicative interaction (V=1.60; 95% CI, 1.16-2.20; six studies) between HCV infection and cigarette smoking. No publication bias was detected.

CONCLUSION

Smoking seems to interact with both HBV and HCV in determining HCC risk. A pooled analysis of individual subject data, with appropriate adjustment with other risk factors, is warranted to confirm these results.

IMPACT

The results of this study imply the evidence of a synergistic effect between smoking and HBV or HCV infection on the risk of HCC. Thus, chronic carriers of HBV or HCV are recommended to avoid smoking.

Update on the epidemiology and systemic treatment of psoriasis

Recent epidemiological observations reveal that the prevalence of psoriasis increases more rapidly in young women compared with young men, and that the prevalence of psoriasis may decrease in the elderly. Emerging evidence suggests that some potentially modifiable exposures, such as smoking, stress and obesity, may increase a patient's risk of developing psoriasis. The evolving literature suggests that psoriasis is associated with multiple other diseases, including cancer, cardiovascular disease, diabetes and psychiatric disease, and that psoriasis itself may be an independent risk factor for developing atherosclerosis and myocardial infarction. The treatment of moderate-to-severe psoriasis is undergoing a revolution with the advent of biological therapies that target the immunopathogenesis of psoriasis, such as tumor necrosis factor-alpha and T-cell function. The pharmacokinetics, pharmacodynamics, efficacy and safety profiles vary among biologicals and, therefore, drug and patient factors are important in selecting the optimum therapy. In this article, we focus on recent developments in the epidemiology and systemic treatment of psoriasis.

Nicotine inhibits Fc epsilon RI-induced cysteinyl leukotrienes and cytokine production without affecting mast cell degranulation through alpha 7/alpha 9/alpha 10-nicotinic receptors

Smokers are less likely to develop some inflammatory and allergic diseases. In Brown-Norway rats, nicotine inhibits several parameters of allergic asthma, including the production of Th2 cytokines and the cysteinyl leukotriene LTC(4). Cysteinyl leukotrienes are primarily produced by mast cells, and these cells play a central role in allergic asthma. Mast cells express a high-affinity receptor for IgE (FcepsilonRI). Following its cross-linking, cells degranulate and release preformed inflammatory mediators (early phase) and synthesize and secrete cytokines/chemokines and leukotrienes (late phase). The mechanism by which nicotine modulates mast cell activation is unclear. Using alpha-bungarotoxin binding and quantitative PCR and PCR product sequencing, we showed that the rat mast/basophil cell line RBL-2H3 expresses nicotinic acetylcholine receptors (nAChRs) alpha7, alpha9, and alpha10; exposure to exceedingly low concentrations of nicotine (nanomolar), but not the biologically inactive metabolite cotinine, for > or = 8 h suppressed the late phase (leukotriene/cytokine production) but not degranulation (histamine and hexosaminidase release). These effects were unrelated to those of nicotine on intracellular free calcium concentration but were causally associated with the inhibition of cytosolic phospholipase A(2) activity and the PI3K/ERK/NF-kappaB pathway, including phosphorylation of Akt and ERK and nuclear translocation of NF-kappaB. The suppressive effect of nicotine on the late-phase response was blocked by the alpha7/alpha9-nAChR antagonists methyllycaconitine and alpha-bungarotoxin, as well as by small interfering RNA knockdown of alpha7-, alpha9-, or alpha10-nAChRs, suggesting a functional interaction between alpha7-, alpha9-, and alpha10-nAChRs that might explain the response of RBL cells to nanomolar concentrations of nicotine. This "hybrid" receptor might serve as a target for novel antiallergic/antiasthmatic therapies.

Influence of smoking on human milk tumor necrosis factor-alpha, interleukin-1beta, and soluble vascular cell adhesion molecule-1 levels at postpartum seventh day

BACKGROUND

The aim of this study was to investigate the effect of maternal smoking during pregnancy on human milk interleukin-1beta, tumor necrosis factor-alpha (TNF-alpha) and soluble vascular cell adhesion molecule-1 levels at the postpartum seventh day.

METHODS

Forty-four mothers (age range: 21-34 years) were enrolled in the study. Mothers were interviewed and classified according to their smoking status into one of two groups: the smoking mothers (n= 21) and the nonsmoking mothers (n= 23).

RESULTS

There were no significant differences between study groups with respect to human milk interleukin-1beta (P= 0.12) and soluble vascular cell adhesion molecule-1 levels (P= 0.83). However, TNF-alpha levels were found to be significantly lower in the smoking mothers compared with the controls (P= 0.002).

CONCLUSION

This study shows that maternal smoking during pregnancy affects the levels of TNF-alpha in milk. The protective effect of human milk against infections seems to be impaired in smoking mothers.

Activation of the cholinergic anti-inflammatory system by nicotine attenuates neuroinflammation via suppression of Th1 and Th17 responses

The alpha7 nicotinic acetylcholine receptor (nAChR) was recently described as an anti-inflammatory target in both macrophages and T cells. Its expression by immune cells may explain the epidemiological data claiming a negative link between cigarette smoking and several inflammatory diseases. In this study, we determined the immunological effects of alpha7 nAChR activation by nicotine. Our results indicate that the alpha7 nAChR is expressed on the surface of CD4(+) T cells and that this expression is up-regulated upon immune activation. Nicotine reduced T cell proliferation in response to an encephalitogenic Ag, as well as the production of Th1 (TNF-alpha and IFN-gamma) and Th17 cytokines (IL-17, IL-17F, IL-21, and IL-22). IL-4 production was increased in the same setting. Attenuation of the Th1 and Th17 lineages was accompanied by reduced T-bet (50%) and increased GATA-3 (350%) expression. Overall, nicotine induced a shift to the Th2 lineage. However, alpha7(-/-)-derived T cells were unaffected by nicotine. Furthermore, nicotine reduced NF-kappaB-mediated transcription as measured by IL-2 and IkappaB transcription. In vivo, administration of nicotine (2 mg/kg s.c.) suppressed the severity of CD4(+) T cell-mediated disease experimental autoimmune encephalomyelitis. alpha7(-/-) mice were refractory to nicotine treatment, although disease severity in those animals was reduced, due to impairment in Ag presentation. Accordingly, CD4(+) and CD11b(+) cells infiltration into the CNS, demyelination, and axonal loss were reduced. Our data implicate a role for the alpha7 nAChR in immune modulation and suggest that alpha7 nAChR agonists may be effective in the treatment of inflammatory disorders.

Combined effects of chronic nicotine and acute virus exposure on neurotrophin expression in rat lung

Strong epidemiologic evidence indicates that tobacco smoke influences frequency and severity of respiratory infections. Previously, we have shown that infection with respiratory syncytial virus upregulates expression of neurotrophic factors and receptors in the lungs, but the effect of tobacco exposure on neurotrophins is unknown. Therefore, we first sought to determine the expression of neurotrophic pathways in lungs of rats chronically exposed to nicotine, and then we studied the interactions between pollution and infection by inoculating virus after nicotine exposure. Expression of the neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor, of their high-affinity tyrosine kinase receptors (trkA and trkB, respectively), and of the low-affinity receptor p75(NTR) was measured in the lungs of nicotine-exposed rats both at the mRNA level by reverse-transcription polymerase chain reaction and at the protein level by enzyme-linked immunoassay. Nicotine increased NGF expression both at the mRNA and protein level and also created a receptor imbalance deriving from increased expression of the pro-inflammatory p75(NTR) receptor without any concomitant change in the high-affinity trkA receptor. Viral infection after chronic nicotine exposure exerted an additive effect on NGF expression, and resulted in exaggerated neurogenic airway inflammation that was abolished by selective inhibition. In conclusion, nicotine levels comparable to those found in smokers are per se able to upregulate the expression of critical neurotrophic molecules in the respiratory tract, and combination of an acute infection following chronic nicotine exposure produces more severe neurotrophic dysregulation and neurogenic-mediated inflammation compared to either infection or nicotine alone.

Nicotine and inflammatory neurological disorders

Cigarette smoke is a major health risk factor which significantly increases the incidence of diseases including lung cancer and respiratory infections. However, there is increasing evidence that smokers have a lower incidence of some inflammatory and neurodegenerative diseases. Nicotine is the main immunosuppressive constituent of cigarette smoke, which inhibits both the innate and adaptive immune responses. Unlike cigarette smoke, nicotine is not yet considered to be a carcinogen and may, in fact, have therapeutic potential as a neuroprotective and anti-inflammatory agent. This review provides a synopsis summarizing the effects of nicotine on the immune system and its (nicotine) influences on various neurological diseases.