Structural and functional changes of rat exocrine pancreas exposed to nicotine

The association between smoking, changes in smoking behavior, and acute pancreatitis: A population-based cohort study in Korea

BACKGROUND AND AIMS

In the Asian population, existing studies regarding the association between smoking and acute pancreatitis are few in number. The aim of this study was to investigate the incidence of acute pancreatitis according to smoking habits and smoking habit changes of the Korean population.

METHODS

We used clinical data from individuals (aged 20 years or older) who received health examinations arranged by the Korean National Health Insurance Service in 2009 (n = 4 238 822) or in 2009 and 2011 (n = 2 617 306). The incidence of acute pancreatitis was analyzed according to smoking status or smoking habit change reported by individuals during their health examination. Newly diagnosed acute pancreatitis was identified using claims data from baseline to the date of diagnosis or until December 31, 2018.

RESULTS

The risk of acute pancreatitis was significantly higher in current smokers compared with never-smokers regardless of age or sex. The adjusted hazard ratio (HR) of acute pancreatitis in current smokers increased according to the amount of smoking (HR 1.28; 95% confidence interval [CI], 1.12-1.45 in <10 cigarettes/day, HR 1.4; CI, 1.3-1.52 in 10-19 cigarettes/day, HR 1.66; CI, 1.55-1.78 in ≥20 cigarettes/day). The adjusted HR of acute pancreatitis in continuous smokers was 1.66 (CI, 1.53-1.8) compared with never-smokers and was higher than smokers who quit smoking (HR 1.34; CI, 1.17-1.54).

CONCLUSIONS

In this Korean population-based cohort study, smoking increased the incidence of acute pancreatitis in a dose-dependent manner, and smoking cessation helped decrease the incidence of acute pancreatitis.

Activation of α7nACh receptor protects against acute pancreatitis through enhancing TFEB-regulated autophagy

Acute pancreatitis (AP) is associated with impaired acinar cell autophagic flux, intracellular zymogen activation, cell necrosis and inflammation. Activation of the cholinergic system of vagus nerve has been shown to attenuate AP, but the effect of organ-intrinsic cholinergic system on pancreatitis remains unknown. In this study, we aim to examine the effect of α7 nicotinic acetylcholine receptor (α7nAChR) stimulation within the pancreas during AP. In vivo, AP was induced by caerulein plus LPS or ethanol plus palmitoleic acid in mice. In vitro, pancreatic acini were isolated and subjected to cholecystokinin (CCK) stimulation. Mice or acini were pre-treated with PNU-282987 (selective α7nAChR agonist) or methyllycaconitine citrate salt (selective α7nAChR antagonist). Pancreatitis severity, acinar cell injury, autophagic flux, and transcription factor EB (TFEB) pathway were analyzed. Both caerulein plus LPS in vivo and CCK in vitro led to an up-regulation of α7nAChR, indicating activation of pancreas-intrinsic α7nAChR signaling during AP. PNU-282987 decreased acinar cell injury, trypsinogen activation and pancreatitis severity. Conversely, methyllycaconitine citrate salt increased acinar cell injury and aggravated AP. Moreover, activation of α7nAChR by PNU-282987 promoted autophagic flux as indicated by reduced p62, increased LysoTracker staining and decreased number of autolysosomes with undegraded contents. Furthermore, PNU-282987 treatment significantly increased TFEB activity in pancreatic acinar cells. α7nAChR activation also attenuated pancreatic inflammation and NF-κB activation. Our results showed that activation of α7nAChR protected against experimental pancreatitis through enhancing TFEB-mediated acinar cell autophagy, suggesting that activation of pancreas-intrinsic α7nAChR may serve as an endogenous protective mechanism during AP.

Pilot Study on the Effect of Biophysical Therapy on Salivary Alpha-Amylase as a Surrogate Measure of Anxiety/Stress: In Search of a Novel Noninvasive Molecular Approach for the Management of Stress

Anxiety and depression impact dramatically on public health, underlying the importance of alternative cost-effective treatments. Previous studies have shown that biophysical treatment can significantly reduce anxiety symptoms and recently, salivary alpha-amylase (SAA) has been identified as an objective correlate of the sympathetic-parasympathetic imbalance related to increased stress burden, defined as allostatic load. The aim of this study was to evaluate the effect of biophysical therapy on SAA levels, in addition to the Depression Anxiety Stress Scale (DASS)-21 questionnaire. Twenty-four workers (sales representatives) presenting with mild anxiety/stress symptoms (Generalized Anxiety Disorder 7-item scale of > 5) were randomized to biophysical treatment (N = 12) or placebo control (N = 12). The biophysical group underwent electromagnetic information transfer through an aqueous system procedure, with daily self-administration for one month. SAA collection and the DASS-21 questionnaire were undertaken at baseline and after one month in all patients. Clinical characteristics and baseline DASS-21 subscale scores were similar between placebo and biophysical group at baseline. After one month, patients receiving biophysical therapy had significantly reduced SAA levels compared to the placebo group (27.8 ± 39.4 vs. 116.8 ± 114.9 U/mL, p = 0.019). All three DASS-21 subscales, depression (9.3 ± 5.1 vs. 5.7 ± 5.5, p = 0.1), anxiety (6.7 ± 25 vs. 3.7 ± 2.2, p = 0.0049) and stress (10.8 ± 4.2 vs. 7.3 ± 3.7, p = 0.041) were also decreased after biophysical treatment compared to placebo after one month. Our findings suggest that biophysical therapy can benefit workers with mild (subclinical) anxiety/stress. These results were also validated by the concomitant reduction of SAA levels and an improvement in DASS-21 subscales. The underlying molecular mechanisms of this therapy remain to be characterized.

Pathophysiological Events Associated With Pancreatitis in Response to Tobacco: An In Vitro Comparative Study With Ethanol in Primary Acinar Cell Culture

OBJECTIVES

The aim of this study was to comparatively analyze the effects of different concentrations of cigarette smoke condensate (CSC, a standardized tobacco extract) and ethanol on intracellular enzyme activation, cell necrosis, alteration of cytosolic calcium concentration ([Ca]c), and amylase secretion in pancreatic acinar cells.

METHODS

The effects of CSC (1 μg/mL to 0.4 mg/mL) and ethanol (10-100 mM) on intracellular enzyme activity, cell necrosis, and [Ca]c were measured by fluorescence assays in isolated pancreatic acinar cells. Amylase secretion was evaluated by spectrophotometry. Supramaximal concentrations of cholecystokinin (10-100 nM) were used as positive control.

RESULTS

Neither CSC nor ethanol induced trypsin or elastase activation. Both CSC (0.1-0.4 mg/mL) and ethanol (10-75 mM) significantly increased [Ca]c. Amylase secretion was increased only in CSC-treated cells (0.3 and 0.4 mg/mL). After 60 minutes, CSC (0.3 and 0.4 mg/mL) significantly increased acinar cell necrosis at a similar percentage to that induced by cholecystokinin. Ethanol did not induce any significant cell necrosis.

CONCLUSIONS

Cigarette smoke condensate induces acinar cell injury and increases [Ca]c and amylase secretion, independently of intracellular enzyme activation, suggesting that tobacco could induce several main early events of pancreatitis in pancreatic acinar cells. However, ethanol only induces increases [Ca]c, having no effect on cell injury, amylase secretion, or intracellular enzyme activation.

A systematic review of possible serious adverse health effects of nicotine replacement therapy

We conducted a systematic literature review to identify and critically evaluate studies of serious adverse health effects (SAHEs) in humans using nicotine replacement therapy (NRT) products. Serious adverse health effects refer to adverse events, leading to substantial disruption of the ability to conduct normal life functions. Strength of evidence evaluations and conclusions were also determined for the identified SAHEs. We evaluated 34 epidemiological studies and clinical trials, relating NRT use to cancer, reproduction/development, CVD, stroke and/or other SAHEs in patients, and four meta-analyses on effects in healthy populations. The overall evidence suffers from many limitations, the most significant being the short-term exposure (≤12 weeks) and follow-up to NRT product use in most of the studies, the common failure to account for changes in smoking behaviour following NRT use, and the sparse information on SAHEs by type of NRT product used. The only SAHE from NRT exposure we identified was an increase in respiratory congenital abnormalities reported in one study. Limited evidence indicated a lack of effect between NRT exposure and SAHEs for CVD and various reproduction/developmental endpoints. For cancer, stroke and other SAHEs, the evidence was inadequate to demonstrate any association with NRT use. Our conclusions agree with recent statements from authoritative bodies.

Epidemiologic and Mechanistic Associations Between Smoking and Pancreatitis

OPINION STATEMENT

Alcohol has long been associated with pancreatitis. Although first described more than three decades ago, smoking has been widely accepted as an important risk factor for all forms of pancreatitis only in the past few years. Empiric data has confirmed smoking as an independent and dose-dependent risk for both acute and chronic pancreatitis. Smoking also increases the risk of recurrences and progression of established chronic pancreatitis. The effects of smoking are enhanced in the presence of alcohol consumption. Indirect evidence suggests that smoking cessation may be beneficial in preventing disease progression. Smoking cessation can therefore be an important strategy for primary as well as secondary prevention of pancreatitis. Therefore, in addition to alcohol, physicians should routinely counsel patients for the benefits of smoking cessation. The mechanisms through which cigarette smoke triggers pathological cellular events, resulting in pancreatitis, are unresolved. Although cigarette smoke contains greater than 4000 compounds, principally nicotine and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) have been broadly studied with regard to pancreatic diseases. Both nicotine and NNK have been shown to induce morphological changes in the pancreas consistent with those seen in pancreatitis. Furthermore, nicotine affects pancreatic secretion and NNK induces premature zymogen activation, two well-known features of pancreatitis. These cigarette toxins may mediate both pro- and anti-inflammatory pathways and can induce changes in pancreatic acinar cell function at the level of transcription, leading to conditions such as thiamin deficiency and mitochondrial dysfunction. Such circumstances could leave the pancreas prone to the development of pancreatitis. This review summarizes relevant research findings and focuses on the epidemiologic links between smoking and pancreatitis, and the cellular pathways that may be significant in induction and evolution of smoking-related pancreatitis.

Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: a New Therapeutic Approach

Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)-at high concentrations-is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert An antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC.

Pathologic cellular events in smoking-related pancreatitis

Pancreatitis, a debilitating inflammatory disorder, results from pancreatic injury. Alcohol abuse is the foremost cause, although cigarette smoking has recently surfaced as a distinct risk factor. The mechanisms by which cigarette smoke and its toxins initiate pathological cellular events leading to pancreatitis, have not been clearly defined. Although cigarette smoke is composed of more than 4000 compounds, it is mainly nicotine and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which have been extensively studied with respect to pancreatic diseases. This review summarizes these research findings and highlights cellular pathways which may be of relevance in initiation and progression of smoking-related pancreatitis.

Smoking as a risk factor for complications in chronic pancreatitis

OBJECTIVES

Several recent studies have demonstrated the association between smoking and chronic pancreatitis (CP). However, less is known about the role of smoking in the development of CP-related complications. Our aim was to investigate the impact of smoking and alcohol consumption on age of onset and complications at CP diagnosis.

METHODS

A cross-sectional case-case study was performed within a prospectively collected cohort of patients with CP. Alcohol consumption and smoking habits were assessed using a standardized questionnaire. Morphologic severity was defined based on endoscopic ultrasound criteria for CP and classified as mild (3-4 criteria), moderate (5-6 criteria), and severe (≥7 criteria or calcifications). Pancreatic exocrine insufficiency (PEI) was diagnosed using the C-mixed triglyceride breath test. Odds ratios (OR) with 95% confidence intervals (CI) for CP-related complications were calculated using a case-case design.

RESULTS

A total of 241 patients were included. Smoking was associated with PEI (OR [95% CI], 2.4 [1.17-5.16]), calcifications (OR [95% CI], 2.33 [1.10-4.95]), and severe morphologic changes (OR [95% CI], 3.41 [1.31-8.85]) but not with pseudocysts or diabetes. Neither smoking nor alcohol consumption was associated with age of onset.

CONCLUSIONS

Tobacco, but not alcohol, is associated with PEI, calcifications, and severe morphologic (≥7 criteria or calcifications) CP at diagnosis. Smoking cessation should be encouraged in patients with CP.

Effect of nicotine on exocytotic pancreatic secretory response: role of calcium signaling

Background

Nicotine is a risk factor for pancreatitis resulting in loss of pancreatic enzyme secretion. The aim of this study was to evaluate the mechanisms of nicotine-induced secretory response measured in primary pancreatic acinar cells isolated from Male Sprague Dawley rats. The study examines the role of calcium signaling in the mechanism of the enhanced secretory response observed with nicotine exposure.

Methods

Isolated and purified pancreatic acinar cells were subjected to a nicotine exposure at a dose of 100 μM for 6 minutes and then stimulated with cholecystokinin (CCK) for 30 min. The cell’s secretory response was measured by the percent of amylase released from the cells in the incubation medium Calcium receptor antagonists, inositol trisphosphate (IP₃) receptor blockers, mitogen activated protein kinase inhibitors and specific nicotinic receptor antagonists were used to confirm the involvement of calcium in this process.

Results

Nicotine exposure induced enhanced secretory response in primary cells. These responses remained unaffected by mitogen activated protein kinases (MAPK’s) inhibitors. The effects, however, have been completely abolished by nicotinic receptor antagonist, calcium channel receptor antagonists and inositol trisphosphate (IP₃) receptor blockers.

Conclusions

The data suggest that calcium activated events regulating the exocytotic secretion are affected by nicotine as shown by enhanced functional response which is inhibited by specific antagonists… The results implicate the role of nicotine in the mobilization of both intra- and extracellular calcium in the regulation of stimulus-secretory response of enzyme secretion in this cell system. We conclude that nicotine plays an important role in promoting enhanced calcium levels inside the acinar cell.

Immunohistochemical localization of somatostatin and pancreatic polypeptide in smokers with chronic pancreatitis

Recent studies have demonstrated a significant role of tobacco smoking in the development of chronic pancreatitis. Although there are published papers on the effects of cigarette smoking on insulin secretion in patients, no data are available on the effects of smoking on pancreatic endocrine cells secreting somatostatin and pancreatic polypeptide. The aim of the study was to evaluate the effects of cigarette smoking on endocrine pancreatic function by immunolocalization of somatostatin and pancreatic polypeptide in the pancreas from smokers and non-smoking patients with chronic pancreatitis in comparison with healthy controls. The LSAB2-HRP technique with polyclonal antibodies was used for the immunolocalization of somatostatin and pancreatic polypeptide in histological preparations of the pancreas. The intensity of immunohistochemical reaction was calculated with digital image analysis. The study demonstrated increased numbers of somatostatin (D) secreting cells and pancreatic polypeptide (PP) cells and their altered location in pancreatic islets and parenchyma of smoking patients with chronic pancreatitis, as compared to non-smoking patients and healthy controls. Smoking patients showed significantly higher immunostaining of the hormones in the pancreas compared to non-smoking patients and healthy persons. This study indicates that smoking may play a significant role in the development of endocrine disturbances in the development of chronic pancreatitis.

Selective expression of CYP2A13 in human pancreatic α-islet cells

Exposure to cigarette smoke is an etiological factor of human pancreatic cancer and has been associated with an increased risk of pancreatic diseases, including pancreatitis and diabetes. The toxicants in cigarette smoke can reach pancreatic tissue, and most of the toxicants require cytochrome P450 (P450)-mediated metabolic activation to exert their toxicity. Among all the human P450 enzymes, CYP2A13 is the most efficient enzyme in the metabolic activation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a major tobacco-specific toxicant and a suspected human carcinogen. It also metabolically activates 4-aminobiphenyl, another toxicant in cigarette smoke. Immunohistochemical analysis in this study demonstrated that CYP2A13 was selectively expressed in the islets but not in the exocrine portion of adult human pancreas. Further study using dual immunofluorescence labeling technique showed that CYP2A13 protein was mainly expressed in the α-islet but not in β-islet cells. The selective expression of CYP2A13 in human pancreatic α-islet cells suggests that these islet cells could be damaged by the toxicants existing in cigarette smoke through CYP2A13-mediated in situ metabolic activation. Our result provides a mechanistic insight for human pancreatic diseases that have been associated with cigarette smoke exposure.

The pathobiological impact of cigarette smoke on pancreatic cancer development (review)

Despite extensive efforts, pancreatic cancer remains incurable. Most risk factors, such as genetic disposition, metabolic diseases or chronic pancreatitis cannot be influenced. By contrast, cigarette smoking, an important risk factor for pancreatic cancer, can be controlled. Despite the epidemiological evidence of the detrimental effects of cigarette smoking with regard to pancreatic cancer development and its unique property of being influenceable, our understanding of cigarette smoke-induced pancreatic carcinogenesis is limited. Current data on cigarette smoke-induced pancreatic carcinogenesis indicate multifactorial events that are triggered by nicotine, which is the major pharmacologically active constituent of tobacco smoke. In addition to nicotine, a vast number of carcinogens have the potential to reach the pancreatic gland, where they are metabolized, in some instances to even more toxic compounds. These metabolic events are not restricted to pancreatic ductal cells. Several studies show that acinar cells are also greatly affected. Furthermore, pancreatic cancer progenitor cells do not only derive from the ductal epithelial lineage, but also from acinar cells. This sheds new light on cigarette smoke-induced acinar cell damage. On this background, our objective is to outline a multifactorial model of tobacco smoke-induced pancreatic carcinogenesis.

The burning question: why is smoking a risk factor for pancreatic cancer?

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease. The prognosis is poor; less than 5% of those diagnosed are still alive five years after diagnosis, and complete remission is still rare. Tobacco smoking is a major risk factor of pancreatic cancer. However, the mechanism(s) through which it causes the disease remains unknown. Accumulating evidence indicates that carcinogenic compounds in cigarette smoke stimulate pancreatic cancer progression through induction of inflammation and fibrosis which act in concert with genetic factors leading to the inhibition of cell death and stimulation of proliferation resulting in the promotion of the PDAC.

Potential carcinogenic effects of cigarette smoke and Swedish moist snuff on pancreas: a study using a transgenic mouse model of chronic pancreatitis

The risk of pancreatic cancer is increased in both Snus (the Swedish variant of oral smokeless tobacco) users and, to a greater extent, in cigarette smokers. Concurrent chronic pancreatitis further increases the risk in cigarette smokers. Little is known about the mechanism by which cigarette smoke or Snus increase the risk of pancreatic cancer in individuals with chronic pancreatitis. This study examined the carcinogenic effects of an aqueous extract of cigarette smoke (tobacco smoke, TS) or Snus in an Elastase-IL-1beta transgenic mouse model of chronic pancreatitis. Both transgenic and wild-type (WT) mice were fed diluted TS water or Snus-containing diet for up to 15 months, and monitored for phenotypic and molecular changes in the pancreas. Both TS- and Snus-treated Elastase-IL-1beta mice, but not WT mice, developed significant pancreatic ductal epithelial flattening and severe glandular atrophy compared with untreated transgenic mice. Ductal epithelial cells displayed a high proliferative index, minimal apoptosis, and induction of COX-2 in the setting of chronic inflammation. Up-regulation of TNF-alpha correlated with the onset of severe glandular atrophy. In comparison with Snus-treated mice, TS-Elastase-IL-1beta mice had an earlier onset and a greater extent of phenotypic changes, which were associated with up-regulation of TNF-alpha and increased expression of IL-6, TGF-beta, and SDF-1. Collectively, these findings provide new insights into the mechanism by which tobacco products are likely to promote carcinogenesis in the setting of chronic pancreatitis.

Desmoplasia of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer and is characterized by remarkable desmoplasia. The desmoplasia is composed of extracellular matrix (ECM) proteins, myofibroblastic pancreatic stellate cells, and immune cells associated with a multitude of cytokines, growth factors, and ECM metabolizing enzymes. The mechanisms of participation of this complex matrix process in carcinogenesis are only starting to be appreciated. Recent studies showed key roles for stellate cells in the production of ECM proteins as well as cytokines and growth factors that promote the growth of the cancer cells all present in the desmoplastic parts of PDAC. In addition, interactions of ECM proteins and desmoplastic secreted growth factors with the cancer cells of PDAC activate intracellular signals including reactive oxygen species that act to make the cancer cells resistant to dying. These findings suggest that the desmoplasia of PDAC is a key factor in regulating carcinogenesis of PDAC as well as responses to therapies. A better understanding of the biology of desmoplasia in the mechanism of PDAC will likely provide significant opportunities for better treatments for this devastating cancer.

Induction of osteopontin expression by nicotine and cigarette smoke in the pancreas and pancreatic ductal adenocarcinoma cells

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease with etiological association with cigarette smoking. Nicotine, an important component of cigarettes, exists at high concentrations in the bloodstream of smokers. Osteopontin (OPN) is a secreted phosphoprotein that confers on cancer cells a migratory phenotype and activates signaling pathways that induce cell survival, proliferation, invasion, and metastasis. Here, we investigated the potential molecular basis of nicotine's role in PDA through studying its effect on OPN. Nicotine significantly (p < 0.02) increased OPN mRNA and protein secretion in PDA cells through activation of the OPN gene promoter. The OPN mRNA induction was inhibited by the nicotinic acetylcholine receptor antagonist, mechamylamine. Further, the tyrosine kinase inhibitor genistein inhibited the nicotine-mediated induction of OPN, suggesting that mitogen activated protein kinase signaling mechanism is involved. Nicotine activated the phosphorylation of ERK1/2, but not p38 or c-Jun NH2-terminal MAP kinases. Inhibition of ERK1/2 activation reduced the nicotine-induced OPN synthesis. Rats exposed to cigarette smoke showed a dose-dependent increase in pancreatic OPN that paralleled the rise of pancreatic and plasma nicotine levels. Analysis of cancer tissue from invasive PDA patients, the majority of whom were smokers, showed the presence of significant amounts of OPN in the malignant ducts and the surrounding pancreatic acini. Our data suggest that nicotine may contribute to PDA pathogenesis through upregulation of OPN. They provide the first insight into a nicotine-initiated signal transduction pathway that regulates OPN as a possible tumorigenic mechanism in PDA.

Long-term nicotine exposure causes increased concentrations of trypsinogens and amylase in pancreatic extracts in the rat

To develop radioimmunoassays (RIAs) for rat trypsinogens 1 and 2 and to investigate the effect of nicotine exposure on concentration and production of pancreatic zymogens in the rat.

METHODS

Male Sprague-Dawley rats were supplied with either normal or nicotine-containing (0.77 mM) water for 28 days and were then killed. Rabbit antibodies for the activation peptides of trypsinogens 1 and 2 were obtained for use in the RIAs. Concentrations of the both trypsinogens in pancreatic extracts were measured by the RIAs after activation by enterokinase. DNA and amylase were measured using commercial kits. mRNA for trypsinogens 1 and 2, procolipase, and cholecystokinin receptor was measured by in situ hybridization.

RESULTS

The specificity of the RIA for the trypsinogen 1 activation peptide was satisfactory. The RIA for the trypsinogen 2 activation peptide showed a limited cross-reaction toward the synthetic trypsinogen 1 activation peptide, but the importance of this cross-reaction was moderate when investigated in samples of activated trypsinogens. Weight gain was reduced in nicotine-treated animals. Concentrations of amylase, trypsinogen 1, trypsinogen 2, and the ratio of trypsinogen 2 to 1 were all increased in pancreatic extracts of nicotine-fed animals. Total DNA and mRNA for the trypsinogens, procolipase, and cholecystokinin receptor were not affected by nicotine exposure.

CONCLUSIONS

The combination of increased proenzyme concentrations and unaffected mRNA levels suggests that nicotine impairs secretion rather than production of pancreatic zymogens.

A prospective cohort study of smoking in acute pancreatitis

BACKGROUND/AIMS

Little is known about risk factors for acute pancreatitis other than gallstones and alcohol consumption. The aim of this study was to investigate if smoking or body mass index (BMI) are associated with acute pancreatitis and to determine relative risks (RR) for acute pancreatitis related to smoking, BMI, and alcohol consumption.

METHODS

From 1974 to 1992, selected birth-year cohorts of residents in Malmo, Sweden (born 1921-1949) were invited to a health-screening investigation including physical examination, blood sampling and a questionnaire. In total, 33,346 individuals participated. Cases of acute pancreatitis were identified from diagnosis registries (n = 179). Incidence rates were calculated in different risk factor categories. A Cox's analysis revealed RR.

RESULTS

Current versus never smoking at baseline was associated with acute pancreatitis (RR 2.14, 95% confidence interval (CI) 1.48-3.09) after adjustment for age, sex, BMI and alcohol consumption. This association was stronger in heavy smokers (20-30 cigarettes/day) (RR 3.19, 95% CI 2.03-5.00). Smoking was associated with a RR of 3.57 (95% CI 0.98-13.0) for acute pancreatitis in subjects who reported no alcohol consumption. An increased risk for acute pancreatitis was also found for high versus low risk, self-reported alcohol consumption (RR 2.55, 95% CI 1.59-4.08) and for gamma-GT levels in the highest versus the lowest quartile (RR 2.14, 95% CI 1.32-3.49). There was also a weak correlation between BMI and acute pancreatitis.

CONCLUSIONS

Smoking is associated with the incidence of acute pancreatitis in a dose-response manner. and IAP.

Cigarette smoke-induced pancreatic damage: experimental data

BACKGROUND AND AIMS

Epidemiological data clearly indicate that cigarette smoking is associated with an increased risk for developing chronic pancreatitis and pancreatic cancer. Despite of this clear epidemiological correlation, cigarette smoke-induced pancreatic damage has only been investigated in a small number of experimental studies.

METHODS

Experimental studies examining the effect of cigarette smoke or cigarette smoke constituents on the pancreas were reviewed.

RESULTS

Recent data indicate that smoking also induces chronic pancreatic inflammation in rodents within a period of 12 weeks upon exposure with environmental cigarette smoke. Supported by the finding that morphologic pancreatic damage is also induced by nicotine treatment, cigarette smoke-induced pancreatic damage is likely to be caused by a disturbance of regulation of exocrine pancreas. The morphological alterations, however, induced by nicotine, are less pronounced and therefore, other substances and pathophysiologic mechanisms, such as carcinogen action or cigarette smoke-induced reduction of anti-protease activity, are likely to aggravate pancreatic damage upon cigarette smoke inhalation.

CONCLUSION

These data indicate that several constituents of cigarette smoke induce a disturbance of pancreatic function. This multifactorial event induces morphologic pancreatic damage upon cigarette smoke exposure in rodents.

Morphological and biological effects of maternal exposure to tobacco smoke on the feto-placental unit

Active and passive maternal smoking has a damaging effect in every trimester of human pregnancy. Cigarette smoke contains scores of toxins which exert a direct effect on the placental and fetal cell proliferation and differentiation and can explain the increased risk of miscarriage, fetal growth restriction (FGR) stillbirth, preterm birth and placental abruption reported by epidemiological studies. In the placenta, smoking is associated from early in pregnancy, with a thickening of the trophoblastic basement membrane, an increase in collagen content of the villous mesenchyme and a decrease in vascularisation. These anatomical changes are associated with changes in placental enzymatic and synthetic functions. In particular, nicotine depresses active amino-acid (AA) uptake by human placental villi and trophoblast invasion and cadmium decreases the expression and activity of 11 beta-hydroxysteroid dehydrogenase type 2 which is causally linked to FGR. Maternal smoking also dysregulates trophoblast expression of molecules that govern cellular responses to oxygen tension. In the fetus, smoking is associated with a reduction of weight, fat mass and most anthropometric parameters and as in the placenta with alterations in protein metabolism and enzyme activity. These alterations are the results of a direct toxic effect on the fetal cells or an indirect effect through damage to, and/or functional disturbances of the placenta. In particular, smoking interferes strongly with the fetal brain and pancreas biological parameters and induces chromosomal instability, which is associated with an increase in the risk of cancer, especially childhood malignancies.

Nicotine-induced proliferation of isolated rat pancreatic acinar cells: effect on cell signalling and function

OBJECTIVES

The aim of the current study was to investigate whether nicotine treatment would induce the proliferation of isolated rat primary pancreatic acinar cells in culture by activating mitogen-activated protein kinase (MAPK) signalling and exocrine secretion.

MATERIALS AND METHODS

A nicotine dose- and time-response curve was initially developed to determine the optimal dose and time used for all subsequent studies. Proliferation studies were conducted by cell counting and confirmed further by bromodeoxyuridine (BrdU) incorporation and flow cytometry assays. MAPK signalling studies were conducted by Western blot analysis. Localization of ERK1/2 signals, with or without nicotine and the MAPK inhibitor, was visualized by immunofluorescence.

RESULTS

Nicotine treatment caused dose-dependent activation of extracellular signal-regulated kinases (ERK1/2), the maxima occurring at 100 micro m and at 3 min after treatment; the response was suppressed by the ERK1/2 inhibitor. Maximal nicotine-induced cell proliferation occurred at 24 h, and UO126-treatment significantly reduced this response. Exposure of cells to 100 microm nicotine for 6 min significantly enhanced both baseline and cholecystokinin-stimulated cell function, and these effects were not affected by treatment with the inhibitor of ERK1/2 but were suppressed by mecamylamine, a nicotinic receptor antagonist.

CONCLUSIONS

Our results suggest that nicotine treatment induced cell proliferation of isolated pancreatic acinar cells and that this is coupled with the activation of MAPK signalling with no effect on its function. Hence, in primary cells, the mechanism of induction and regulation of these two processes, cell proliferation and cell function, by nicotine treatment are independent of each other.

The genetics of nicotine dependence: Relationship to pancreatic cancer

Smoking of tobacco products continues to be a major cause of worldwide health problems. Epidemiological studies have shown that tobacco smoking is the greatest risk factor for the development of pancreatic cancer. Smokers who are able to quit smoking can reduce their risk of pancreatic cancer by nearly 50% within two years, however, their risk of developing pancreatic cancer remains higher than that of non-smokers for 10 years. Nicotine is the major psychoactive substance in tobacco, and is responsible for tobacco dependence and addiction. Recent evidence suggests that individuals have genetically based differences in their ability to metabolize nicotine, as well as genetic differences in the psychological reward pathways that may influence individual response to smoking initiation, dependence, addiction and cessation. Numerous associations have been reported between smoking behavior and genetic polymorphisms in genes that are responsible for nicotine metabolism. In addition, polymorphisms in genes that encode neurotransmitters and transporters that function in psychological reward pathways have been implicated in differences in smoking behavior. However, there is a large degree of between-study variability that demonstrates the need for larger, well-controlled case-control studies to identify target genes and deduce mechanisms that account for the genetic basis of inter-individual differences in smoking behavior. Understanding the genetic factors that increase susceptibility to tobacco addiction may result in more effective tobacco cessation programs which will, in turn, reduce the incidence of tobacco related disease, including pancreatic cancer.

Estimating the health consequences of replacing cigarettes with nicotine inhalers

BACKGROUND

A fast acting, clean nicotine delivery system might substantially displace cigarettes. Public health consequences would depend on the subsequent prevalence of nicotine use, hazards of delivery systems, and intrinsic hazards of nicotine.

METHODS

A spreadsheet program, DEMANDS, estimates differences in expected mortality, adjusted for nicotine delivery system features and prevalence of nicotine use, by extending the data and methods of the SAMMEC 3 software from the US Centers for Disease Control and Prevention. The user estimates disease risks attributable to nicotine, other smoke components, and risk factors that coexist with smoking. The public health consequences of a widely used clean nicotine inhaler replacing cigarettes were compared to historical observations and public health goals, using four different risk attribution scenarios and nicotine use prevalence from 0-100%.

MAIN OUTCOME MEASURES

Changes in years of potential life before age 85 (YPL85).

RESULTS

If nicotine accounts for less than a third of smokers' excess risk of SAMMEC diseases, as it most likely does, then even with very widespread use of clean nicotine DEMANDS predicts public health gains, relative to current tobacco use. Public health benefits accruing from a widely used clean nicotine inhaler probably equal or exceed the benefits of achieving Healthy People 2010 goals.

CONCLUSIONS

Clean nicotine inhalers might improve public health as much as any feasible tobacco control effort. Although the relevant risk estimates are somewhat uncertain, partial nicotine deregulation deserves consideration as part of a broad tobacco control policy.

Pathophysiological effects of nicotine on the pancreas: an update

Epidemiological evidence strongly suggests an association between cigarette smoking and pancreatic diseases. It is well recognized that nicotine, a major component in cigarette smoke, is an addictive agent and, therefore, reinforces smoking behavior. The current review update focuses on the genetics of nicotine dependence and its role on the development of pancreatic diseases. The role of smoking and nicotine in pancreatitis and pancreatic cancer development is also discussed. Exposure of laboratory animals to nicotine clearly supports the notion that nicotine can induce pancreatic injury. The mechanism by which nicotine induces such effects is perhaps mediated via signal transduction pathways in the pancreatic acinar cell, leading to enhanced levels of intracellular calcium release, resulting in cytotoxicity and eventual cell death. The induction of pancreatic injury by nicotine may also involve activation and expression of protooncogene, H-ras, which can increase cytosolic calcium via second messenger pathways. Development of pancreatic carcinoma in cigarette smokers as observed in human populations may be the result of activation and mutation of the H-ras gene. A possible pathogenetic mechanism of nicotine in the pancreas activating multiple signal transduction pathways is schematically summarized in Figure 1.