A meta-analysis of the role of smoking in inflammatory bowel disease

Microproteinuria in patients with inflammatory bowel disease: Is it associated with the disease activity or the treatment with 5-aminosalicylic acid?

AIM: To investigate whether microproteinuria in patients with inflammatory bowel disease (IBD) is associated with the disease activity or the treatment with 5-aminosalicylic acid (5-ASA).

METHODS: We prospectively studied microproteinuria in 86 consecutive patients with IBD, 61 with ulcerative colitis (UC) and 25 with Crohn’s disease (CD), before as well as 2 and 6 months after their inclusion in the study. Forty-six patients received 5-ASA for a period of 28.8 months (range 1-168 mo). Microalbuminuria (mALB) and urine levels of the renal tubular proteins β₂-microglobulin (β₂mGLB) and β-N-acetyl-D-glucosamidase (β-NAG) as well as the creatinine clearance were determined in a 12-h overnight urine collection. Tumor necrosis factor-α (TNF-α) serum levels were also measured.

RESULTS: A total of 277 measurements (194 in UC patients and 83 in CD patients) were performed. The prevalence of abnormal microproteinuria in UC and CD patients was 12.9% and 6.0% for mALB, 22.7% and 27.7% for β₂mGLB, and 11.3% and 8.4% for β-NAG, respectively. mALB was not associated with IBD activity. β₂mGLB and β-NAG urine levels were correlated to UC activity (UCAI: P<0.01; UCEI: P<0.005). mALB in UC patients and β-NAG urine levels in CD patients were related to TNF-α serum levels. An association was noticed between microproteinuria and smoking habit. Treatment with 5-ASA was not correlated to the severity of microproteinuria or to the changes of creatinine clearance.

CONCLUSION: Microproteinuria is mainly associated with UC and its activity but not affected by 5-ASA.

Preliminary observations of oral nicotine therapy for inflammatory bowel disease: an open-label phase I-II study of tolerance

BACKGROUND

Transdermal nicotine provides benefit in active ulcerative colitis but is often associated with adverse events (AEs). An oral formulation has been developed to minimize AEs. This study was undertaken to make initial observations on the safety and tolerance of oral nicotine therapy in inflammatory bowel disease; the effect on disease activity was also noted.

METHODS

Twenty-six patients with ulcerative colitis, 11 with active disease, and 5 patients with Crohn's colitis (2 with active disease) were given oral nicotine in 3-mg capsules, gradually increasing the dose to the maximum tolerated. AEs were recorded, concomitant prednisolone and/or azathioprine were reduced where possible, and disease activity was reassessed at the end of nicotine treatment.

RESULTS

Patients were followed for up to 12 months. Twenty-nine of 31 could tolerate at least 6 mg of nicotine each day, and 5 patients tolerated at least 18 mg daily. Twenty-four patients had nicotine-related nonserious AEs; over one half occurred during the period of dose escalation, but 7 discontinued treatment because of them. Six of the 13 patients with active disease became asymptomatic, whereas 3 patients in remission developed active symptoms; 11 patients reduced their concomitant medication.

CONCLUSIONS

Oral nicotine is a safe potential treatment of inflammatory bowel disease, but there is considerable variation in tolerance.

State of the art: IBD therapy and clinical trials in IBD

Inflammatory bowel diseases (IBD) encompass Crohn's disease and ulcerative colitis, which are diseases characterized by chronic intestinal inflammation. IBD is believed to result from predisposing genetic and environmental factors (specific antigens and pathogen-associated molecular patterns) acting on the immunoregulatory system and causing inflammation of the gastrointestinal mucosa. IBD may be the result of an imbalance of effector (proinflammatory) and regulatory T-cell responses. Three scenarios indicative of the outcome of this balance exist in animal models: balanced effector and regulatory T cells resulting in a normal controlled inflammation; overactive effector T cells resulting in inflammation and disease; and an absence of regulatory T cells resulting in uncontrolled inflammation and severe, aggressive disease. The number of products under study for the treatment of IBD has increased from 3 products and 1 target in 1993 to more than 30 products and more than 10 targets in 2005. The number of products under development and continued investigations into the pathogenesis of IBD emphasize the need to expand clinical research efforts in IBD.

Mechanisms of Disease: nicotine—a review of its actions in the context of gastrointestinal disease

Smoking tobacco is associated with a number of gastrointestinal disorders. In some, such as Crohn's disease and peptic ulcer disease, it increases the risk of disease and has a detrimental effect on their course. In others, such as ulcerative colitis, it decreases the risk of disease and can have a favorable effect on disease course and severity. In the eighteenth and nineteenth centuries, nicotine was used as a 'panacea' for various ailments, including abdominal symptoms--it is now under investigation to elucidate its role in gastrointestinal diseases that are associated with smoking. The actions of nicotine are complex; it is likely that its effects on the central nervous system, gastrointestinal tract and immune system interact with other risk factors, such as genetic susceptibility, to influence disease outcomes. This review focuses on the mechanisms of action of nicotine that might be relevant in gastrointestinal disease.

A randomized trial of nicotine enemas for active ulcerative colitis

BACKGROUND & AIMS

Ulcerative colitis (UC) is largely a disease of nonsmokers in which transdermal nicotine improves the symptoms but often causes adverse events (AEs). Nicotine enemas cause fewer AEs and were used as supplemental treatment for active UC.

METHODS

We treated 104 patients with active UC with either 6-mg nicotine enemas or placebo enemas for 6 weeks in a randomized double-blind study. Patients continued their oral therapy, if any, for UC: 68 patients were taking mesalamine, 15 patients were taking prednisolone, and 12 patients were taking thiopurines during the study. Clinical, sigmoidoscopic, and histologic assessments were made at baseline and at the end of the study and symptoms were recorded daily on a diary card. The primary end point was induction of clinical remission and clinical improvement also was measured by the UC disease activity index. After the study, patients then used nicotine enemas daily for 4 weeks and sigmoidoscopy with a biopsy examination was repeated. AEs and salivary cotinine levels were monitored throughout the study.

RESULTS

Clinical remission was achieved in 14 of 52 (27%) patients on active treatment and 14 of 43 (33%) patients on placebo (P = .55). The UC disease activity index improved by 1.45 points in the active group and by 1.65 points for those on placebo (P = .88). Only 1 patient discontinued treatment because of an AE (abdominal pain). In the 47 patients taking mesalamine only, active treatment conferred benefit that was not statistically significant; disease remission occurred in 9 of 25 patients on active therapy and 4 of 21 patients on placebo (P = .20).

CONCLUSIONS

Six-milligram nicotine enemas were well tolerated but were not found to be efficacious for active UC.

Carriage of CARD15 variants and smoking as risk factors for resective surgery in patients with Crohn's ileal disease

BACKGROUND

It is controversial whether CARD15 variants are truly associated with a more severe form of Crohn's disease. The relative role of CARD15 genotype and smoking in Crohn's disease progression is also debated.

AIM

To investigate the association between CARD15 variants and history of resective surgery in patients with Crohn's ileal disease, taking into account smoking as a possible confounding factor.

METHODS

We originally assessed CARD15 genotype in 239 north Italian Crohn's disease patients (mean follow-up: 10.1 +/- 8.1 years). We then focused on 193 patients with proven ileal involvement, 70 of whom (36.3%) carried CARD15-mutated alleles (G908R, R702W, L1007fs).

RESULTS

Carriage of CARD15 variants was positively associated with family history and ileal-only disease and negatively associated with uncomplicated behaviour at maximal follow-up (P < 0.05). Ileal resection was the only variable independently associated with CARD15 variants at multivariate analysis (OR 3.8; 95% CI 1.6-9.2; P = 0.003). Kaplan-Meier analysis showed that ileal resection was favoured both by CARD15 variant-carriage (P = 0.01) and by smoking (P = 0.05), but smoking did not affect progression to surgery in variant carriers (P = 0.31). Thirteen of 14 (93%) patients being resection-free at 15-year follow-up, had CARD15 wild-type genotype (P = 0.01), whereas only seven (50%) had never smoked (P = 1.0).

CONCLUSIONS

In summary, CARD15 variant-associated Crohn's ileitis is virtually committed to stricturing and/or penetrating disease and, eventually, to resective surgery. Smoking accelerates progression to surgery in patients with wild-type CARD15 genotype, but it seems to exert no additional effect in CARD15-variant carriers.

Cutaneous Effects of Smoking

BACKGROUND

Cigarette smoking is the single biggest preventable cause of death and disability in developed countries and is a significant public health concern. While known to be strongly associated with a number of cardiovascular and pulmonary diseases and cancers, smoking also leads to a variety of cutaneous manifestations.

OBJECTIVE

This article reviews the effects of cigarette smoking on the skin and its appendages.

METHODS

A literature review was based on a MEDLINE search (1966-2004) for English-language articles using the MeSH terms cutaneous, dermatology, tobacco, skin, and smoking. An additional search was subsequently undertaken for articles related to smoking and associated mucocutanous diseases, with the focus on pathogenesis and epidemiologic data. Articles presenting the highest level of evidence and latest reports were preferentially selected.

RESULTS

Smoking is strongly associated with numerous dermatologic conditions including poor wound healing, wrinkling and premature skin aging, squamous cell carcinoma, psoriasis, hidradenitis suppurativa, hair loss, oral cancers, and other oral conditions. In addition, it has an impact on the skin lesions observed in diabetes, lupus, and AIDS. The evidence linking smoking and melanoma, eczema, and acne is inconclusive. Anecdotal data exist on the possible protective effects of smoking in oral/genital aphthosis of Behçet's disease, herpes labialis, pyoderma gangrenosum, acral melanoma, and Kaposi's sarcoma in AIDS patients.

CONCLUSIONS

An appreciation of the adverse cutaneous consequences of smoking is important. Dermatologists can play an integral role in promoting smoking cessation by providing expert opinion and educating the public on the deleterious effects of smoking on the skin.

Thrombosis and inflammatory bowel disease

Interaction between thrombosis and inflammation is increasingly recognized. With this, interest has arisen in the role of thrombosis in inflammatory conditions, including the inflammatory bowel diseases. Although the association between active inflammatory bowel disease and thromboembolic complications has long been known, there has been a resurgence in research into the role of thrombosis and the hemostatic system in the pathogenesis of both ulcerative colitis and Crohn's disease. Here we review the increased frequency of thromboembolic complications occurring in patients with inflammatory bowel disease; whether thrombosis might play a part in the initiation and maintenance of inflammation in inflammatory bowel disease; abnormalities of the coagulation system found in patients with inflammatory bowel disease; platelet dysfunction in inflammatory bowel disease; the mechanisms by which hemostatic processes might be proinflammatory in inflammatory bowel disease; and how these interactions might impact not only on the prevention of complications, but also on the treatment of the underlying inflammation in inflammatory bowel disease.

Role of helminths in regulating mucosal inflammation

The rapid rise in prevalence of ulcerative colitis (UC) and Crohn's disease (CD) in highly developed countries suggests that environmental change engenders risk for inflammatory bowel disease (IBD). Eradication of parasitic worms (helminths) through increased hygiene may be one such change that has led to increased prevalence of these diseases. Helminths alter host mucosal and systemic immunity, inhibiting dysregulated inflammatory responses. Animals exposed to helminths are protected from experimental colitis, encephalitis, and diabetes. Patients with CD or UC improve when exposed to whipworm. Lamina propria (LP) mononuclear cells from helminth-colonized mice make less interleukin (IL)-12 p40 and IFN-gamma, but more IL-4, IL-13, IL-10, TGF-beta, and PGE(2) compared to LP mononuclear cells from naive mice. Systemic immune responses show similar skewing toward Th2 and regulatory cytokine production in worm-colonized animal models and humans. Recent reports suggest that helminths induce regulatory T cell activity. These effects by once ubiquitous organisms may have protected individuals from many of the emerging immune-mediated illnesses like IBD, multiple sclerosis, type I diabetes, and asthma.

Worse clinical course of disease in Crohn's patients with previous appendectomy

OBJECTIVES

The aim of the present study was to assess the effect of previous appendectomy in a series of Crohn's disease (CD) patients on the clinical characteristics and course of disease.

METHODS

Demographic and clinical data were retrospectively analysed for 129 consecutive outpatients (68 men and 61 women, median age 38 years) with CD. For each patient, information concerning appendectomy, indication for surgery (acute/chronic) and the date of surgery were recorded. The date of the appendectomy in relation to the date of CD diagnosis was carefully assessed in order to evaluate the precise relationship between the two events. A total of 129 CD patients who had not undergone previous appendectomy served as controls. The severity of disease was assessed retrospectively by evaluating the need for systemic steroids, immunosuppressants and surgical treatment for CD, particularly resective procedures.

RESULTS

Forty-one CD patients (31.8%) underwent appendectomy before the diagnosis of disease. Appendectomy before diagnosis showed a negative association with colonic disease localization and with articular manifestations. In addition, the 41 patients with previous appendectomy had a significantly greater risk of surgery, particularly resective. Multivariate analysis confirmed appendectomy performed before diagnosis as an independent risk factor for surgery; on the contrary, colonic site and inflammatory type of disease were independent factors protecting against surgery. Although current smokers were at an increased risk of surgical treatment, a smoking habit alone did not seem to be relevant at the multivariate analysis.

CONCLUSION

The results of this study indicate a worse clinical course of CD in patients appendicectomized before diagnosis.

Review article: smoking cessation as primary therapy to modify the course of Crohn's disease

This article aims to offer an updated review of the effects of smoking on inflammatory bowel disease, and provide a review of the methods of achieving smoking cessation. A systematic review of Embase and Medline databases was conducted. Smoking causes opposing effects on ulcerative colitis and Crohn's disease. The odds ratio of developing ulcerative colitis for smokers compared with lifetime non-smokers is 0.41. Conversely, smokers with Crohn's disease have a more aggressive disease requiring more therapeutic intervention. Smoking cessation is associated with a 65% reduction in the risk of a relapse as compared with continued smokers, a similar magnitude to that obtained with immunosuppressive therapy. Although difficult to achieve smoking cessation can best be encouraged by accessing appropriate counselling services, nicotine replacement therapy and bupropion. Using a combination of these treatments there is an improved chance of success of up to 20% compared with an unassisted quit attempt. Smoking cessation unequivocally improves the course of Crohn's disease and should be a primary therapeutic aim in smokers with Crohn's disease.

Novel approaches to inflammatory bowel disease

Ulcerative colitis and Crohn's disease, collectively known as inflammatory bowel disease (IBD), are chronic, spontaneously relapsing disorders of unknown cause. These diseases appear to be immunologically mediated and have genetic and environmental influences. Although the cause of these diseases remains obscure, the pathogenesis of chronic intestinal inflammation is becoming clearer, due to improved animal models of enterocolitis and important advances in immunological techniques. Traditional therapy for IBD, although helping to induce and maintain disease remission, does little to alter the underlying fundamental disease process. New IBD therapy has not developed significantly over the past twenty years and includes 5-aminosalicylic acid preparations, corticosteroids and immunomodulatory agents, such as azathioprine, 6-mercaptopurine and methotrexate. There is, therefore, a need for new, specific disease-modifying therapy and the development of such therapy has been hastened by a greater understanding of the pathophysiology of IBD. This review examines the most recent novel therapies for IBD, with specific emphasis on immunomodulatory and novel anti-inflammatory therapies. Recent clinical trials are reviewed, and the potential advances and clinical impact that these novel agents may provide are discussed.

Gastrointestinal parasites: potential therapy for refractory inflammatory bowel diseases

Crohn's disease and ulcerative colitis are chronic relapsing inflammatory bowel diseases (IBDs). Different pharmacological agents are currently used in several combinations to control the inflammatory process. Recently, antibodies against the proinflammatory cytokine tumor necrosis factor-alpha appeared to be very effective in treating patients with Crohn's disease. However, due to the fact that the pathogen causing IBD is still unknown, no causative treatment is currently available that is able to make the disease disappear. Recently, the hygiene hypothesis of the development of immunological diseases was proposed, stating that raising children in extremely hygienic environments with less exposure to parasite infections may negatively affect the development of the immune system, predisposing them to immunologic diseases such as IBD. This hypothesis is supported by experimental data showing that helminthic parasites protect against T helper (TH) type 1 cell-mediated gastrointestinal inflammations like Crohn's disease. Both TH-2 cells and regulatory T cells may be involved in this immunomodulatory mechanism. Here, we review the experimental and clinical studies in favor of the hygiene hypothesis, opening perspectives on new therapies for IBD.

Lymphocyte telomere dynamics and telomerase activity in inflammatory bowel disease: effect of drugs and smoking

BACKGROUND

The chromosome instability observed in peripheral blood lymphocytes in ulcerative colitis could be a biomarker of cancer susceptibility.

AIM

To determine whether accelerated telomere shortening could explain chromosome instability and assess the effect of drugs and smoking on telomere dynamics in these cells.

METHODS

Peripheral blood lymphocytes were isolated from ulcerative colitis, Crohn's disease and non-inflammatory bowel disease control patients. Telomere lengths were measured by quantitative real-time polymerase chain reaction. After activation and cell separation, telomerase activity and human telomerase reverse transcriptase messenger ribonucleic acid were measured by telomerase repeat amplification protocol enzyme-linked immunosorbent serological assay and quantitative real-time polymerase chain reaction, respectively.

RESULTS

Age-related telomere loss in peripheral blood lymphocytes was similar in ulcerative colitis, Crohn's disease and control patients. Telomerase activity decreased with age in all groups and correlated positively with telomere length (r = 0.489, P = 0.006). Among Crohn's disease patients, azathioprine was associated with decreased telomerase activity (0.66 vs. 1.54, P = 0.026, P < 0.05) and smoking was associated with decreased human telomerase reverse transcriptase mRNA expression (10.5 vs. 33.3, P = 0.036, P < 0.05).

CONCLUSIONS

Telomere shortening is not accelerated and therefore cannot be the cause of the chromosome instability observed in ulcerative colitis peripheral blood lymphocytes. Azathioprine and cigarette smoking modify telomerase expression in these cells.

Cigarette smoking and age at diagnosis of inflammatory bowel disease

OBJECTIVES

The incidence and age of onset of inflammatory bowel disease (IBD) appear to be changing. The aim of this study was to determine whether the prevalence of cigarette smoking differs among patients with Crohn's disease (CD) or ulcerative colitis (UC) at the time of diagnosis compared with the general population and whether smoking history is related to the type and age of IBD onset.

METHODS

Prevalence rates of smoking at the time of IBD diagnosis were compared between patients with CD and UC from the IBD Center at the University of Pittsburgh Medical Center versus age-, gender-, and time period-adjusted rates in the Pennsylvania general population. Analyses also were stratified by gender and diagnoses before and after 40 years of age, i.e., early and late onset.

RESULTS

There were 263 IBD patients (144 UC patients and 119 CD patients) seen in the IBD center between August 2000 and December 2002. The prevalence of active smoking was significantly higher at diagnosis in CD patients compared with the Pennsylvania general population (33% versus 24%, P = 0.04), particularly in those with CD onset at 40 years of age or later (47% versus 27%, P = 0.005). In contrast, smoking prevalence was significantly lower in UC patients than the general population (9% versus 28%, P < 0.0001), particularly among those with UC onset before the age of 40 years (6% versus 27%, P < 0.0001). Smoking cessation was associated with an approximate, but nonsignificant, 3-fold higher likelihood of late-onset UC compared with CD.

CONCLUSIONS

Cigarette smoking is associated with the development of late-onset CD and is protective against developing UC at any age, particularly early onset. Former smoking is associated with a high likelihood of developing late-onset UC, but not CD.

The IBD international genetics consortium provides further evidence for linkage to IBD4 and shows gene-environment interaction

BACKGROUND AND AIMS

The inflammatory bowel diseases (IBDs) Crohn's disease (CD) and ulcerative colitis are complex disorders with an important genetic determinant. One gene associated with CD has been identified: NOD2/CARD15. Two independent genome-wide scans found significant evidence (logarithm of odds [LOD] 3.6) and suggestive evidence (LOD 2.8) for linkage on locus 14q11-12, also known as the IBD4 locus. To further characterize this locus, we assessed gene-environment interaction (IBD4 x smoking) and phenotypic heterogeneity in a large cohort of IBD-affected sibling pairs as part of an ongoing international collaborative effort.

PATIENTS AND METHODS

A total of 733 IBD families, comprising 892 affected sibling pairs, were genotyped for microsatellites D14S261, D14S283, D14S972, and D14S275, spanning the IBD4 locus. Information on gender, ethnicity, age at onset, smoking at diagnosis, extraintestinal manifestations, and disease location was available.

RESULTS

A significant distortion in the mean allele sharing (MAS) between affected siblings was observed for CD patients only at each of the four markers (54.6%, 52.8%, 50.4%, and 53.3%, respectively). Maximum linkage for CD was observed at marker D14S261 (multipoint nonparametric linkage score 2.36; P

CONCLUSIONS

The IBD International Genetics Consortium replicated the IBD4 locus on chromosome 14q for CD and also showed evidence for a gene-environment interaction at this locus. Further studies are needed to explore the mechanism by which smoking influences IBD4.

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MESH Headings

• Adolescent
• Adult
• Age of Onset
• Chromosomes, Human, Pair 14
• Cohort Studies
• Environment
• Female
• Genetic Predisposition to Disease
• Genotype
• Humans
• Inflammatory Bowel Diseases/etiology
• Inflammatory Bowel Diseases/genetics
• Male
• Microsatellite Repeats
• Pedigree
• Quantitative Trait Loci
• Siblings
• Smoking/adverse effects

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Affiliation(s)

Marie Pierik Department of Gastroenterology, University Hospital Gasthuisberg, Leuven, Belgium.
Huiying Yang
Michael M Barmada
Juleen A Cavanaugh
Vito Annese
Steven R Brant
Judy H Cho
Richard H Duerr
Jean-Pierre Hugot
Dermot P McGovern
Paulina Paavola-Sakki
Graham L Radford-Smith
P Pavli
Mark S Silverberg
Stephan Schreiber
Kent D Taylor
Robert Vlietinck

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The pharmacological actions of nicotine on the gastrointestinal tract

Increasing use of tobacco and its related health problems are a great concern in the world. Recent epidemiological findings have demonstrated the positive association between cigarette smoking and several gastrointestinal (GI) diseases, including peptic ulcer and cancers. Interestingly, smoking also modifies the disease course of ulcerative colitis (UC). Nicotine, a major component of cigarette smoke, seems to mediate some of the actions of cigarette smoking on the pathogenesis of GI disorders. Nicotine worsens the detrimental effects of aggressive factors and attenuates the protective actions of defensive factors in the processes of development and repair of gastric ulceration. Nicotine also takes part in the initiation and promotion of carcinogenesis in the GI tract. In this regard, nicotine and its metabolites are found to be mutagenic and have the ability to modulate cell proliferation, apoptosis, and angiogenesis during tumoriogenesis through specific receptors and signalling pathways. However, to elucidate this complex pathogenic mechanism, further study at the molecular level is warranted. In contrast, findings of clinical trials give promising results on the use of nicotine as an adjuvant therapy for UC. The beneficial effect of nicotine on UC seems to be mediated through multiple mechanisms. More clinical studies are needed to establish the therapeutic value of nicotine in this disease.

Breastfeeding and risk of inflammatory bowel disease: a systematic review with meta-analysis

BACKGROUND

It has long been believed that breastfeeding provides protection against ulcerative colitis and Crohn disease. Studies designated to test this hypothesis were conducted without reaching conclusive results.

OBJECTIVE

The aim of this meta-analysis was to examine the role of breastfeeding in preventing inflammatory bowel disease and to summarize the evidence gathered about this subject.

DESIGN

A meta-analysis was performed on 17 relevant articles that were found by using MEDLINE, EMBASE, the Internet, and articles' references. The publications were fully reviewed and divided, on the basis of their quality, into 3 groups.

RESULTS

Studies showed heterogeneous results. The pooled odds ratios of all the 17 reviewed studies, calculated according to the random-effects model, were 0.67 (95% CI: 0.52, 0.86) for Crohn disease and 0.77 (0.61, 0.96) for ulcerative colitis. However, only 4 studies for Crohn disease and 4 for ulcerative colitis were eventually included in the highest quality group. In this group, the pooled odds ratio was 0.45 (0.26, 0.79) for Crohn disease and 0.56 (0.38, 0.81) for ulcerative colitis.

CONCLUSIONS

The results of this meta-analysis support the hypothesis that breastfeeding is associated with lower risks of Crohn disease and ulcerative colitis. However, because only a few studies were graded to be of high quality, we suggest that further research, conducted with good methodology and large sample sizes, should be carried out to strengthen the validity of these observations.

Smoking and systemic disease

Cigarette smoking is associated with a number of adverse health effects, including well-established links to cardiopulmonary disease and several cancers. Some of the other important systemic diseases associated with smoking are the subjects of this article, such as diabetes mellitus and insulin resistance and thyroid diseases. Also reviewed here is the negative impact of smoking on male and female infertility, on selected dermatologic conditions, and on gastrointestinal diseases including peptic ulcer and inflammatory bowel diseases.

Metabolism and biochemical effects of nicotine for primary care providers

Nicotine is a colorless and volatile liquid alkaloid naturally occurring in the leaves and stems of Nicotiana tabacum and Nicotiana rustica. Nicotine, the primary component of tobacco, is responsible for both tobacco product addiction (with chronic exposure) and the odor associated with tobacco. In addition to cigarettes, nicotine is found in chewing gum, transdermal patches, nasal spray, and sublingual tablets. Following its inhalation and absorption, nicotine and its metabolic products exert diverse physiologic and pharmacologic effects. This article covers the absorption and metabolism of nicotine, nicotine toxicity, pharmacologic effects of nicotine, nicotine-drug interactions, and the use of nicotine for the treatment of disease.

Inflammatory bowel disease and smoking: a review of epidemiology, pathophysiology, and therapeutic implications

The relationship between smoking behavior and inflammatory bowel disease (IBD) is complex. While Crohn's disease (CD) is associated with smoking and smoking has detrimental effects on the clinical course of the disease, ulcerative colitis (UC) is largely a disease of nonsmokers and former smokers. Furthermore, cigarette smoking may even result in a beneficial influence on the course of ulcerative colitis. The potential mechanisms involved in this dual relationship include changes in humoral and cellular immunity, cytokine and eicosanoid levels, gut motility, permeability, and blood flow, colonic mucus, and oxygen free radicals. Nicotine is assumed to be the active moiety. The differential therapeutic consequences comprise the cessation of smoking in CD and, so far, clinical trials using nicotine in different forms of application for UC. In this article, we review the relationship between cigarette smoking and IBD, considering epidemiological, pathogenetic, and clinical aspects.

Nicotine enemas for treatment of ulcerative colitis: a study of the pharmacokinetics and adverse events associated with three doses of nicotine

BACKGROUND

Transdermal nicotine is of value in active ulcerative colitis but causes adverse events because of systemic absorption. Nicotine enemas may give rise to fewer adverse events.

AIM

To assess the pharmacokinetics of nicotine enemas in three doses.

METHODS

Thirteen volunteers, all non-smokers but three ex-smokers, were given enemas on separate occasions containing 3, 6 and 9 mg of nicotine, in ascending dose order. Adverse events were recorded and blood samples taken over 8 h for measurement of serum nicotine and cotinine.

RESULTS

Enemas were retained by most subjects. Eleven of 14 adverse events were 'early'--30-105 min after the enema, corresponding to maximum plasma nicotine concentrations; three events were later, 4-8 h after the enema and unrelated to the tmax. 'Early' adverse events occurred in eight subjects--six with 9 mg. The three highest plasma nicotine concentrations were with 9 mg and associated with headache, nausea and sweating. Only one had adverse events with 3 mg and withdrew from the study. Nicotine Cmax with 6 and 9 mg doses were respectively two and three times the value with 3 mg. Peak nicotine concentrations occurred 44-50 min after the enema.

CONCLUSION

The 6 mg dose of nicotine probably represents the dose to use in clinical practice - for the highest therapeutic dose with a low risk of adverse events.

Unravelling the complex genetics of inflammatory bowel disease

The rapid pace of progress in molecular genetics over the past 15 years--since the seminal description of the polymerase chain reaction--has led to the identification of the genes involved in many single gene disorders. These successes in the laboratory have already led directly to clinical applications in diagnosis, pharmacogenetics, and the development of new therapies. Progress in unravelling the genetics of complex diseases has been less straightforward. However, real excitement has followed the identification of the NOD 2/CARD 15 gene as an important determinant of susceptibility to Crohn's disease.(1,)(2) Not only has this finding provided a proof of principle for the technique of genome-wide scanning in complex disorders, but the discovery also has given real insight into the primary pathophysiology involved in chronic inflammatory bowel disease. The background to this discovery and its implications form the basis for the present article.

Tobacco and IBD: relevance in the understanding of disease mechanisms and clinical practice

Current smoking protects against ulcerative colitis and, after onset of the disease, improves its course, decreasing the need for colectomy. However, smoking increases the risk of developing Crohn's disease and worsens its course, increasing the need for steroids, immunosuppressants and reoperations. Smoking cessation aggravates ulcerative colitis and improves Crohn's disease. The effects of smoking are the sum of contradictory effects of various substances, including nicotine and carbon monoxide, and are modulated by gender, genetic background, disease location and activity, cigarette dose and nicotine concentration. Smokers with ulcerative colitis should not be discouraged from stopping smoking but encouraged to stop, to reduce their risk of cardiopulmonary tobacco-related diseases. In Crohn's disease, smoking cessation has become a major therapeutic goal, particularly in young women and in patients with ileal involvement. A large amount of supportive information, use of nicotine-replacement therapies and antidepressants, and individual counselling might aid the patient in quitting.

Factors associated with disease activity of pouchitis after surgery for ulcerative colitis

BACKGROUND

Pouchitis occurs in 20% to 59% of patients operated on for ulcerative colitis. Several risk factors have been identified for the development of pouchitis. This study was undertaken to assess the incidence of pouchitis at least 5 years after ileal pouch-anal anastomosis for ulcerative colitis, and to evaluate possible predictive factors for inflammation activity.

METHODS

A total of 107 subjects were enrolled (54 M, 53 F, mean age 45 years, range 23-69) with a J-pouch created between 1985 and 1994. Preoperative medical history was determined, an endoscopy performed, and biopsies taken from the pouch and neoterminal ileum above the pouch. Sera from all patients were tested for perinuclear antineutrophil cytoplasmic antibodies (pANCAs).

RESULTS

After a mean 7.5-years' follow-up time, the cumulative incidence of pouchitis was 58%. Risk for development of active inflammation (PDAI > or = 7) was significantly higher in patients with preoperative extraintestinal manifestations (OR 2.7, 95% CI 1.1-6.4, P=0.03). Patients who had had ankylosing spondylitis (AS) (OR 11.7, P=0.006) or iritis (OR 9.8, P=0.013) were especially at risk. Positive titres of pANCAs were associated with inflammation in the neoterminal ileum; 80% of patients with high pANCA levels (>100) had pouchitis. Current smokers tended to have a more benign disease course.

CONCLUSIONS

A correlation existed between the prevalence and titre of pANCAs and extent and disease activity of pouchitis. Chronic pouchitis may continuously stimulate the immunological process, keeping pANCAs at detectable levels. A strong correlation between AS, iritis and pouchitis suggests a common link in their pathogenesis.

Environmental risk factors (excluding tobacco and microorganisms): critical analysis of old and new hypotheses

The increase in incidence in both ulcerative colitis and Crohn's disease during the 20th century has led to an abundance of different hypotheses on what sort of exposures are responsible. There has been a special focus on dietary factors, as well as on other exposures introduced on a population-based level, including fast food, cola drinks, toothpaste, antibiotics and oral contraceptives. The aim of this review is to critically assess the results from the different observational studies that have investigated these hypotheses, and also to propose research agendas that should be pursued in the future. The conclusion is that infectious exposures and early bacterial colonization, which are associated with better hygiene early in life and that influence immune function, and possibly oral contraceptives, remain the only exposures of interest for future research into the aetiology of ulcerative colitis and Crohn's disease.

Clinical epidemiology of inflammatory bowel disease: Incidence, prevalence, and environmental influences

Although the incidence and prevalence of ulcerative colitis and Crohn's disease are beginning to stabilize in high-incidence areas such as northern Europe and North America, they continue to rise in low-incidence areas such as southern Europe, Asia, and much of the developing world. As many as 1.4 million persons in the United States and 2.2 million persons in Europe suffer from these diseases. Previously noted racial and ethnic differences seem to be narrowing. Differences in incidence across age, time, and geographic region suggest that environmental factors significantly modify the expression of Crohn's disease and ulcerative colitis. The strongest environmental factors identified are cigarette smoking and appendectomy. Whether other factors such as diet, oral contraceptives, perinatal/childhood infections, or atypical mycobacterial infections play a role in expression of inflammatory bowel disease remains unclear. Additional epidemiologic studies to define better the burden of illness, explore the mechanism of association with environmental factors, and identify new risk factors are needed.

Cigarette smoking and appendectomy are risk factors for extraintestinal manifestations in ulcerative colitis

OBJECTIVE

Two common factors, cigarette smoking and appendectomy, have been found to play a role in ulcerative colitis (UC). Data on their role in the development of extraintestinal manifestations (EIM) are scarce.

METHODS

The relationship between cigarette smoking, appendectomy, and EIM was examined in a prospective study involving 535 (M/F = 319/216) consecutive UC patients followed up for 18 yr. We considered the major EIM: seronegative spondyloarthropathy, pyoderma gangrenosum/erythema nodosum, acute anterior uveitis, and primary sclerosing cholangitis. We excluded patients with a history of EIM or those colectomized before study entry, ex-smokers, and those who started to smoke during the course of UC.

RESULTS

In UC patients, seronegative spondyloarthropathy and dermatologic complications were found increased in smokers (p < 0.0001; p = 0.001) or in subjects with appendectomy (p = 0.0003; p = 0.02), while acute anterior uveitis and primary sclerosing cholangitis did not differ. The Kaplan-Meier analysis showed 18-yr rates for EIM of 71% in smokers and 45% in nonsmokers (log-rank test, p = 0.0001), and of 85% in patients with appendectomy and 48% in those without (p = 0.0001). Cox proportional-hazard model showed that cigarette smoking and appendectomy are independent factors promoting EIM. In smokers with appendectomy the adjusted hazard ratio (3.197, 95% CI 1.529-6.684) was higher than in patients with appendectomy alone (2.617, 95% CI 1.542-4.442) or smoking alone (1.947, 95% CI 1.317-2.879).

CONCLUSIONS

In UC patients, appendectomy and cigarette smoking are prognostic factors for the development of EIM. The unfavorable effect of cigarette smoking on EIM is additive to that of appendectomy.

Maintenance of Remission in Crohn???s Disease

Crohn's disease is a chronic inflammatory bowel disorder with a relapsing and remitting course. Once remission is achieved, the main aim of the management of Crohn's disease is maintenance of that remission. Significant advances have been made into understanding the aetiology and pathogenesis of inflammatory bowel disease. With these advances in understanding come increasing numbers of new agents and therapies, aimed both at active disease and the subsequent maintenance of remission in Crohn's disease. Current therapeutic strategies in maintaining remission in Crohn's disease include 5-aminosalicylates (e.g. sulfasalazine, mesalazine), thiopurines (e.g. azathioprine, 6-mercaptopurine [mercaptopurine]), methotrexate and infliximab. The 5-aminosalicylates appear to have efficacy limited to either surgically induced remission and/or limited small bowel Crohn's disease. The immunomodulators now have an established role in Crohn's maintenance. Azathioprine and 6-mercaptopurine are effective in chronic active disease and corticosteroid-dependent Crohn's disease. Methotrexate has similar indications, although it appears to be an alternative in patients who are intolerant of, or resistant to, the thiopurines. The most recent breakthrough has been in the field of biological therapy for maintenance of remission in Crohn's disease. Treatment of patients with the anti-tumour necrosis factor (TNF)-alpha antibody infliximab has been shown already to be effective in inducing remission. Recent studies have now confirmed a role for infliximab in delaying relapse and maintaining remission in patients responsive to infliximab induction therapy. However, results with soluble TNF alpha receptors have been disappointing. A number of other biological and nonbiological agents have shown potential, though trials of the 'newer' biological agents have thus far been disappointing, in the maintenance of remission in Crohn's disease. The evidence for theses agents is currently limited, in many cases to treating active disease; however, these data are discussed in this article in order to provide an overview of future potential therapies. The aim of this review is to provide clinicians with an insight into current and emerging therapeutic agents for the maintenance of remission of Crohn's disease.

Current perspective on the pathogenesis of Graves' disease and ophthalmopathy

Graves' disease (GD) is a very common autoimmune disorder of the thyroid in which stimulatory antibodies bind to the thyrotropin receptor and activate glandular function, resulting in hyperthyroidism. In addition, some patients with GD develop localized manifestations including ophthalmopathy (GO) and dermopathy. Since the cloning of the receptor cDNA, significant progress has been made in understanding the structure-function relationship of the receptor, which has been discussed in a number of earlier reviews. In this paper, we have focused our discussion on studies related to the molecular mechanisms of the disease pathogenesis and the development of animal models for GD. It has become apparent that multiple factors contribute to the etiology of GD, including host genetic as well as environmental factors. Studies in experimental animals indicate that GD is a slowly progressing disease that involves activation and recruitment of thyrotropin receptor-specific T and B cells. This activation eventually results in the production of stimulatory antibodies that can cause hyperthyroidism. Similarly, significant new insights have been gained in our understanding of GO that occurs in a subset of patients with GD. As in GD, both environmental and genetic factors play important roles in the development of GO. Although a number of putative ocular autoantigens have been identified, their role in the pathogenesis of GO awaits confirmation. Extensive analyses of orbital tissues obtained from patients with GO have provided a clearer understanding of the roles of T and B cells, cytokines and chemokines, and various ocular tissues including ocular muscles and fibroblasts. Equally impressive is the progress made in understanding why connective tissues of the orbit and the skin in GO are singled out for activation and undergo extensive remodeling. Results to date indicate that fibroblasts can act as sentinel cells and initiate lymphocyte recruitment and tissue remodeling. Moreover, these fibroblasts can be readily activated by Ig in the sera of patients with GD, suggesting a central role for them in the pathogenesis. Collectively, recent studies have led to a better understanding of the pathogenesis of GD and GO and have opened up potential new avenues for developing novel treatments for GD and GO.

Update on the genetics of inflammatory bowel disease

There is a general consensus that interplay of genetic and environmental factors leads to an overactive mucosal immune response, which mediates the tissue damage in inflammatory bowel disease. Ethnic aggregation of inflammatory bowel disease (particularly, increased incidence and prevalence in the Ashkenazim), familial aggregation of inflammatory bowel disease, and greater concordance for inflammatory bowel disease in monozygotic twins than dizygotic twins are 3 lines of evidence for a central role of genetic factors in the pathogenesis. The genetics of inflammatory bowel disease cannot be explained by simple Mendelian genetics; it is characterized by incomplete penetrance, multiple susceptibility loci and genetic heterogeneity. Unraveling the complex genetics of inflammatory bowel disease is a daunting challenge, but the perseverance of inflammatory bowel disease gene hunters has produced commendable results in recent years. Since 1996, the field of inflammatory bowel disease genetics has progressed from publication of the first systematic genome searches for inflammatory bowel disease susceptibility loci to the identification of Crohn disease-associated genetic variants in CARD15/NOD2. Strategies for finding additional inflammatory bowel disease genes include taking advantage of the greater resolution and power of linkage disequilibrium mapping, mapping by admixture disequilibrium in African-American and Hispanic-American populations, stratifying genetic analyses by genotypes at known inflammatory bowel disease loci, and refining inflammatory bowel disease phenotypes to reduce genetic heterogeneity and simplify the search for additional inflammatory bowel disease genes.

Cigarette smoke exposure increases ulcerative colitis-associated colonic adenoma formation in mice

Both chronic ulcerative colitis and smoking are associated with colorectal cancer in humans. In the present study, we investigated the effects of cigarette smoke (CS) exposure on inflammation-associated tumorigenesis in the mouse colon. Male balb/c mice were allocated into six groups: control, CS (2%), CS (4%), colitis, colitis + CS (2%) and colitis + CS (4%). They were given water or 3% dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis, with or without 1 h daily exposure to 2 or 4% CS. They were then allowed to drink water for 14 days. The cycle of 7 day DSS +/- CS/14 day H2O treatments were repeated twice. Mice were killed immediately or 1 month after the three cycles of treatments. Results indicated colonic adenoma was only found in the colitis group (one out of 11), Colitis + CS (2%) group (seven out of 12) and colitis + CS (4%) group (four out of five) 1 month after three cycles of DSS and/or CS treatment. CS exposure dose-dependently increased adenoma formation in mice with inflamed mucosa. CS exposure plus colitis was strongly associated with a high incidence of dysplasia (P < 0.01) and adenocarcinoma formation (P < 0.01) compared with induction of colitis alone. Colitis induced cell proliferation and apoptosis in colonic tissues. Cigarette smoking significantly attenuated the apoptotic effect by DSS probably via the induction of anti-apoptotic protein bcl-2. The ratio of apoptosis over proliferation was also significantly lower in the colitis + CS groups. Vascular endothelial growth factor and angiogenesis in the colon were also increased by cigarette smoking in animals with colitis. In conclusion, CS promotes inflammation-associated adenoma/adenocarcinoma formation in the mouse colon in a dose-dependent manner. This tumor development is associated with the inhibition of cellular apoptosis and supported by increased angiogenesis.

Inflammatory bowel disease: dysfunction of GALT and gut bacterial flora (II)

The precise cause(s) of Crohn's disease and ulcerative colitis are unknown. From animal models and human studies it is well established that gut bacterial flora are essential for inducing the bowel inflammation. Animal models, when kept in a germ-free environment, do not develop colitis until the gut flora is reconstituted. It is not clear whether the bacterial antigens (Ags) from the normal flora or some other pathogenic bacterial Ags induce/propagate the inflammatory process in inflammatory bowel disease (IBD). Despite extensive research it has not been possible to identify any specific bacteria or virus as a credible cause of IBD. Recent understanding of quorum sensing molecules (QSMs) secreted by bacteria helps to explain the community behaviour in bacterial species. When QSMs reach a defined concentration, they activate bacterial proliferation and a number of virulence genes. Also, these molecules have been found to modulate the immune system to the advantage of the gut bacteria. They have not been well studied, however, in the gut. Inappropriate secretion of QSMs may alter the gut-associated lymphoid tissue (GALT) and, thereby, deregulate the immune tolerance normally present. Usefulness of probiotics and their immune modulating effects are being increasingly reported. Probiotics are also being used in the treatment of IBD. The interaction between the epithelial cells and the gut flora is very important as this is the first line of contact; this interaction may determine the induction of tolerance and mucosal integrity or immune activity, tissue inflammation and abnormal permeability. The latter is documented in patients with IBD and their healthy relatives. This may be an important factor in disruption of mucosal integrity and GALT dysfunction.

Differential effects of cigarette smoke extracts on cell proliferation in gastric and colon cells

Substantial evidence show a higher incidence of gastric cancer in smokers than nonsmokers and that cigarette smoking is highly associated with colon cancer. The present study was designed to examine the effect of cigarette smoke extracts on gastric and colon cancer cell proliferation, which is important for tumor growth. Two different cell lines were used. One was gastric cancer cell line AGS, and the other was colon cancer cell line HT-29. It was found that cigarette smoke extracts stimulated cell proliferation and c-myc expression in AGS cells. Furthermore, this proliferative action was partially blocked by the c-myc antisense. However, the extracts significantly inhibited HT-29 cell proliferation and suppressed c-myc expression. In conclusion, cigarette smoke extracts stimulated AGS cell proliferation, while inhibiting HT-29 proliferation, which were partially mediated by a c-myc-related pathway. The former action may play a contributory role in the carcinogenic action of cigarette smoking in the stomach.

Is smoking an indirect risk factor for the development of ulcerative colitis? An age- and sex-matched case-control study

BACKGROUND

It has been suggested that smoking protects against the development of ulcerative colitis (UC). Evidence is mainly driven from the way data from a multitude of case-control studies have been interpreted.

METHODS

An age- and sex-matched case-control study was conducted to further assess the association between history of smoking, past surgery, childhood, and other potential causative factors with the development of UC using the answers to a detailed questionnaire. The data were analyzed using univariate analysis and logistic regression. The results are presented as odds ratios (OR) and 95% confidence intervals.

RESULTS

One hundred and two cases and an equal number of matched controls were included in the study. Using a three-level comparison, at the age of diagnosis, the risks of developing UC were 0.41 (0.19-0.87), 3.45 (1.62-7.35) and 0.78 (0.44-1.37) for smokers, ex-smokers and non-smokers, respectively. When compared to individuals who have never smoked, ex-smokers were at a higher risk of developing the disease (OR = 3.00 (1.38-6.51)). The specific history of quitting smoking prior to the age of onset of symptoms was associated with an increased risk for developing the disease (OR = 3.45 (1.62-7.35)).

CONCLUSIONS

Active smoking was associated with a low risk for the development of UC, but the lack of history of smoking was not associated with an increase in the risk. History of quitting smoking prior to the onset of symptoms, in contrast, was associated with a significant increase in the risk of developing the disease. These findings make the theory of a simple protective effect of smoking on the development of UC difficult to justify. It may be plausible to suggest that the withdrawal of the immunosuppressive effect of smoking triggers the disease onset in a genetically susceptible individual or simply unmasks its symptoms.

Antioxidant vitamin supplementation in Crohn's disease decreases oxidative stress. a randomized controlled trial

OBJECTIVE

We showed previously that patients with Crohn's disease (CD) had increased oxidative stress and lower antioxidant vitamins compared with healthy controls. This is despite inactive or mildly active disease and maintenance therapy. The aim of this study was to evaluate in these patients the effects of antioxidant vitamin supplementation on oxidative stress.

METHODS

This is a randomized controlled trial where stable but oxidatively stressed CD subjects (n = 57) were supplemented with vitamins E (800 IU) and C (1000 mg) or their placebo for 4 wk. Oxidative stress measured by breath pentane and ethane output, plasma lipid peroxides, and F2-isoprostane was assessed at baseline and at 4 wk. Disease activity was also monitored by measuring CD activity index and plasma orosomucoid.

RESULTS

During supplementation, plasma vitamin C and alpha-tocopherol increased and all indices of oxidative stress decreased significantly. Disease activity remained stable.

CONCLUSIONS

In this population, vitamin E and C supplementation resulted in a significant reduction in oxidative stress. This suggests that patients with inactive or mildly active CD can be oxidatively stressed and have increased requirement in antioxidant vitamins.

Effect of acute cigarette smoking, alone or with alcohol, on gastric barrier function in healthy volunteers

BACKGROUND

Smoking is a risk factor for gastroduodenal ulcer and gastric adenocarcinoma. However, the pathophysiological mechanisms induced by acute cigarette smoking in the human gastric mucosa are poorly understood.

AIM

To evaluate the effect of acute cigarette smoking, alone or with alcohol, on the gastric permeability to sucrose, a specific marker of mucosal damage in the stomach.

SUBJECTS AND METHODS

Twenty healthy volunteers (8 smokers/12 non-smokers) were studied. Each fasted subject ingested 500 ml of a 20% sucrose solution and the amount of sucrose excreted in a 5-hour urine collection was measured by gas chromatography Four sucrose permeability tests were carried out: 1. basal, 2. while smoking 5 cigarettes, 3. after drinking 50 ml of a 40 degrees alcoholic beverage, 4. a combination of 2+3.

RESULTS

Sucrose excretion increased after alcohol ingestion (40.5 +/- 6.0 mg vs 143.1 +/- 28.9 mg, p = 0.002), but was not modified by acute cigarette smoking (34.4 +/- 5.9 mg). When alcohol and cigarettes were simultaneously consumed, the increase in alcohol-induced sucrose excretion was significantly reduced (73.1 +/- 16.6 mg, p = 0.03). Basal sucrose excretion was similar in smokers and non-smokers. However, in acute cigarette smoking, a decrease in sucrose excretion was observed in smokers (p = 0.02) but not in non-smokers.

CONCLUSIONS

These results indicate that acute cigarette smoking may tighten the gastric mucosa in habitual smokers and this is associated with a smaller increase of gastric permeability induced by alcohol.

Role of appendicitis and appendectomy in the pathogenesis of ulcerative colitis: a critical review

Besides a genetic predisposition, a causal role of various environmental factors has been considered in the etiology of ulcerative colitis (UC). The association between appendectomy and UC has recently been the subject of intense scrutiny in the hope that it may lead to the identification of important pathogenetic mechanisms. Published data from animal models of colitis demonstrated reduction in experimental colitis after appendectomy, especially if performed at an early age. Several epidemiological case control and cohort studies have shown a strong and consistent relationship. The metaanalysis of 17 case-controlled studies showed an overall odds ratio 0.312 (95% confidence intervals = 0.261-0.373) in favor of appendectomy (p < 0.0001). One of the two recent large cohort studies is in agreement with these results, but the other failed to confirm them. All these studies have suggested that alterations in mucosal immune responses leading to appendicitis or resulting from appendectomy may negatively affect the pathogenetic mechanisms of UC. Further investigation of the role of appendectomy in UC is expected to open new fields for basic scientific research and may lead to the improvement of our understanding for the disease pathogenesis.

Psychosocial factors in peptic ulcer and inflammatory bowel disease

Over the past decade, while gastroenterologists' interest in mind-body interactions in organic disorders dwindled, stronger evidence has linked psychosocial factors with the incidence and recurrence of peptic ulcer and with the course of inflammatory bowel disease. Psychological-behavioral approaches to treatment continue to be disappointing. Psychosocial factors may affect ulcer by increasing duodenal acid load, altering local circulation or motility, intensifying Helicobacter pylori infection, stimulating corticosteroid secretion, and affecting health risk behaviors; possible mechanisms for inflammatory bowel disease include immune deregulation, gut permeability changes, and poor medication adherence. Both belong to the growing category of diseases thought to have an infectious component: for peptic ulcer the bacterium Helicobacter pylori, for inflammatory bowel disease an exaggerated immune response to gut bacteria. Peptic ulcer and inflammatory bowel disease, which present unique interactions among psychological, immunologic, endocrine, infectious, and behavioral factors, are splendid paradigms of the biopsychosocial model.

Chronic nicotine administration differentially alters jejunal and colonic inflammation in interleukin-10 deficient mice

BACKGROUND

Cigarette smoking alters the course of inflammatory bowel disease, is associated with protection against ulcerative colitis, but aggravates or has no effect on Crohn's disease. While the aetiology of this discrepancy remains unclear, differences between location of involvement in ulcerative colitis and Crohn's disease have not been examined in these studies.

AIM

To examine the effects of nicotine administration on the course of jejunitis and colitis in interleukin-10 deficient mice.

METHODS

Male C57/BL10 IL-10 -/- and wild type mice were given nicotine (12.5 microg/ml) in their drinking water at age 12-14 weeks when they had developed clinical signs of inflammatory bowel disease. Gender and age matched control mice received tap water alone. All mice were killed after 2 weeks of treatment. Whole tissue sections of jejunum, proximal and distal colon were separated and examined by macroscopic and histological score. Northern blots were examined for somatostatin, intestinal trefoil factor and mucin-2.

RESULTS

At 14-16 weeks, when the mice were killed, IL-10 -/- untreated control mice developed jejunitis (macroscopic score 1.4 +/- 0.5, microscopic score 2.0 +/- 0.2) and colitis (2.0 +/- 0.2 and 5.9 +/- 0.9, respectively). IL-10 -/- mice treated for 2 weeks with nicotine had significantly reduced colonic scores (1.4 +/- 0.6 and 2.2 +/- 0.15, respectively). In contrast, the jejunum was more severely damaged (2.6 +/- 0.4 and 4.0 +/- 0.3; P = 0.01, respectively). Nicotine significantly increased both somatostatin and intestinal trefoil factor mRNA expression in the colon but not in the jejunum; no effect was noted on mucin-2 or beta-actin mRNA expression.

CONCLUSIONS

(1) Two weeks of nicotine administration leads to contrasting effects on jejunal and colonic inflammation in IL-10 -/- mice. (2) Nicotine ameliorated inflammation in the colon, which was associated with enhanced expression of two protective peptides.

Inflammatory Bowel Disease in Children

Crohn's disease and ulcerative colitis remain medically incurable conditions with potentially significant morbidity. The treatment of children with these conditions therefore should seek to reduce or eliminate symptoms, optimize nutritional status, promote normal growth and development, prevent complications, and minimize the potential psychologic effects of chronic illness. Treatment strategies must seek to both induce and maintain clinical remission. For all but the most mildly affected children with Crohn's disease, a combination of nutritional and pharmacologic approaches is optimal. For those with ulcerative colitis, anti-inflammatory medication is necessary. Moderate to severe Crohn's disease acutely responds best to potent immunomodulatory therapy, eg, corticosteroids and infliximab. Either agent must be coupled with 6-mercaptopurine or azathioprine to maintain long-term remission and to minimize toxicity. Particular attention must be paid to limit the growth suppression and other toxic effects of corticosteroids. Elemental or semielemental enteral nutrition also can induce remission effectively, but relapse is common after primary nutritional therapy is discontinued, mandating concomitant pharmacologic therapy with either 6-mercaptopurine or azathioprine. The availability of 6-mercaptopurine/azathioprine metabolite testing allows optimization of immunomodulatory therapy, detection of noncompliance, and avoidance of potentially dangerous toxicity. Mild ulcerative colitis acutely responds to treatment with a 5-aminosalicylate medication. Long-term remission frequently can be maintained with the same medication. Moderate to severe disease activity requires potent immunomodulatory therapy if colectomy is to be avoided. Surgery is a potential cure for patients with ulcerative colitis, although the development of pouchitis after ileal pouch anal anastomosis is common and frequently requires long-term medical management. Surgery provides only palliative relief of complications in those with Crohn's disease. Emerging therapies, especially evolving biologic and probiotic agents, offer hope for better treatments in the years ahead.

Treatment of distal colitis with local anaesthetic agents

The results of clinical and experimental studies on topical treatment of distal colitis with local anaesthetic agents are summarized. The original observation was an adrenergic hyperinnervation of the inflamed mucosa (hyperinnervation hypothesis). In order to silence local nervous reflexes, the mucosa was treated topically with 2% lidocaine gel. The clinical results are promising and no side effects have been observed. The relapse rate is relatively high and related to the duration of treatment. In studies of experimental colitis a potential antagonism between harmful adrenergic nerves (vasoconstrictor substances and proinflammatory cytokines) and mucosa-protective visceral afferents (antiinflammatory cytokines) in the pathogenesis of colitis is intriguing. Other studies have emphasized the importance of neutrophils for causing damage to the colon epithelium (neutrophil hypothesis) and local anaesthetics have potent effects on several steps of the inflammatory response in addition to the nervous blockade.

Inflammatory bowel disease and environmental influences

Some environmental factors have been established firmly as influences on the development of IBD, such as smoking and appendectomy. Other behaviors, such as oral contraceptive use and sugar intake, have been suggested as risk factors, but he data conflict sharply. The importance of other behaviors, such as breast-feeding, is even murkier with sharply divergent data. Some issues studied may not be factors in themselves but rather markers for other unidentified influences. The conflicting evidence in many of these studies may be clarified as specific genes are identified and the interplay between these environmental factors and genetic subtypes is investigated.

Medical therapy for ulcerative colitis

Although newer therapeutic agents are being developed for the treatment of inflammatory bowel disease, aminosalicylates and corticosteroids remain the mainstay of treatment for UC (Tables 2-5). Patients who do not respond to these agents or become steroid dependent require immunomodulatory therapy or curative surgery. Cyclosporine represents the greatest treatment advance for UC in 10 years. The role of nicotine, heparin, antibiotics, probiotics, and SCFA in the treatment of UC is less clear, but these agents may offer an alternative therapeutic approach for patients intolerant or nonresponsive to standard therapy.

The genetics of inflammatory bowel disease

The complex genetics of IBD is characterized by more than one susceptibility locus, genetic heterogeneity, incomplete penetrance, and probable gene-gene and gene-environment interactions. Functional candidate gene association studies during the past few decades have revealed only modest associations between IBD and genetic variants in the HLA genes and a limited number of other genes that are involved in immune regulation and the inflammatory response. Important advances in IBD genetics research have come about from systematic genome searches for IBD loci. The identification of Crohn's disease-associated NOD2 genetic variants that appear to alter the innate immune response to bacteria is a seminal finding that perhaps is the greatest advance toward understanding the pathogenesis of IBD in decades. The future discovery of other IBD genetic risk factors, facilitated by the completion of the human genome sequencing and annotation, may allow the development of better therapies, possibly including preventive therapies, for patients with Crohn's disease and ulcerative colitis.

Etiopathogenesis of inflammatory bowel disease: the importance of the pediatric perspective

Inflammatory bowel disease (IBD) is now recognized as a common chronic disease affecting children and adolescents. This article will review recent advances made in the fields of genetics, epidemiology, gut ecology, and immunology regarding the etiopathogenesis of IBD, with particular emphasis on the contributions made by pediatric studies. Areas where further study of the pediatric age group would be beneficial will be highlighted.

Assessing health-related quality of life in patients with inflammatory bowel disease, in Crete, Greece

BACKGROUND

Health Related Quality of Life (HRQoL) is an important outcome measure in Inflammatory Bowel Disease (IBD). The aim of our study was to assess HRQoL in a population of 135 Greek patients with IBD.

METHODS

A cohort of 135 patients with IBD, 81 with ulcerative colitis (UC) and 54 with Crohn's disease (CD) were enrolled in our study. Demographic and disease-related data were recorded. HRQoL was assessed by a disease-specific and a generic questionnaire, IBDQ and SF-36, respectively. Disease activity was assessed by Harvey-Bradshaw Index and the Colitis Activity Index for CD and UC patients, respectively.

RESULTS

Among all variables recorded in our study, only disease activity had a significant effect on HRQoL. Patients with active disease scored significantly lower on both IBDQ and SF-36 when compared to those in remission. Only two among the four IBDQ dimensions, bowel and systemic, had significant ability in distinguishing best patients in remission from those with active disease.

CONCLUSIONS

IBD has a negative impact on HRQoL. Patients with active disease are more impaired than patients in remission. In our population of patients bowel and systemic dimensions had a predominant value in patients' perception of quality of life. Patients in our study using the same instrument scored higher than previously reported.