The bisphosphonate alendronate improves the damage associated with trinitrobenzenesulfonic acid-induced colitis in rats

Cotinus coggygria Scop. Attenuates Acetic Acid-Induced Colitis in Rats by Regulation of Inflammatory Mediators

In traditional medicine, many medicinal plants are used in the treatment of various diseases caused by inflammation. The objective of the present study is to elucidate for the first time the effects of Cotinus coggygria (CC) ethanol extract (CCE) on colonic structure and inflammation of acetic acid-induced ulcerative colitis in rats. Colonic damage was assessed using disease activity index score, enzyme-linked immunosorbent assay, and hematoxylin-eosin staining. Also, in vitro antioxidant activity of CCE was investigated by ABTS methods. Total phytochemical content of CCE was measured spectroscopically. Acetic acid caused colonic damage according to disease activity index and macroscopic scoring. CCE significantly reversed these damages. While the levels of proinflammatory cytokines TNF-alpha, IL-1beta, IL-6, and TGF-1beta increased in tissue with UC, IL-10 level decreased. CCE increased inflammatory cytokine levels to values close to the sham group. At the same time, while markers indicating disease severity such as VEGF, COX-2, PGE2, and 8-OHdG indicated the disease in the colitis group, these values returned to normal with CCE. Histological research results support biochemical analysis. CCE exhibited significant antioxidant against ABTS radical. Also, CCE was found to have a high content of total polyphenolic compounds. These findings provide evidence that CCE might be benefit as a promising novel therapy in the treatment of UC in humans due to high polyphenol content and justify the use of CC in folkloric medicine for treatment of inflamed diseases.

Therapeutic Potential of BMP7 in the Treatment of Osteoporosis Caused by the Interaction between Inflammation and Corticosteroids in Inflammatory Bowel Disease

Individuals with inflammatory bowel disease (IBD) have an increased risk of bone impairment, which is a process controlled by the RANKL/RANK/OPG system, mostly due to chronic inflammation and corticosteroid treatment. Bone morphogenic protein 7 (BMP7) has a complex role in maintaining inflammation and bone remodeling but little is known about its anti-inflammatory potential in chronic colitis. We investigated the effect of systemically administered BMP7 and corticosteroids on the severity of inflammation, macrophage differentiation, and bone regeneration in a chronic IBD model.

METHODS

Chronic colitis was induced in male Sprague Dawley rats via weekly administration of 2,4,6-trinitrobenzenesulfonic acid over 21 days following BMP7 or corticosteroid treatment for five days. The levels of serum and colon tissue inflammatory cytokines, RANKL/OPG system, as well as markers of macrophage polarization, were detected using RT-PCR, ELISA, or immunohistochemistry. Long bone and spine analyses were performed using microcomputed tomography (micro-CT).

RESULTS

The administration of BMP7 reduced the adverse effects of colitis and led to elevated OPG and RANK in the colon with a simultaneous decrease in TNF-α and an increase in IL-10 and TGF-β. Decreased expression of the M2 macrophage marker CD163 was found in the BMP7-treated rats compared with the colitis group, whereas the number of M1 marker iNOS-positive cells did not differ between the groups. As a result of the BMP7 treatment, morphometric parameters of trabecular bone increased, and increased trabecular separation noted in the colitis group did not appear.

CONCLUSIONS

We showed that BMP7 suppressed the inflammatory response in chronic colitis, mainly by shifting the cytokine balance and by triggering alterations in the RANKL/OPG system rather than through a macrophage polarization imbalance. In addition, considering the demonstrated effect of BMP7 on bone morphology and structure, it can be suggested that BMP7 plays a role in the managing of osteoporosis in chronic colitis, and thus, its therapeutic potential in the treatment of IBD should be further evaluated.

Cellular Carcinogenesis: Role of Polarized Macrophages in Cancer Initiation

Simple Summary

Inflammation is a hallmark of many cancers. Macrophages are key participants in innate immunity and important drivers of inflammation. When chronically polarized beyond normal homeostatic responses to infection, injury, or aging, macrophages can express several pro-carcinogenic phenotypes. In this review, evidence supporting polarized macrophages as endogenous sources of carcinogenesis is discussed. In addition, the depletion or modulation of macrophages by small molecule inhibitors and probiotics are reviewed as emerging strategies in cancer prevention.

Abstract

Inflammation is an essential hallmark of cancer. Macrophages are key innate immune effector cells in chronic inflammation, parainflammation, and inflammaging. Parainflammation is a form of subclinical inflammation associated with a persistent DNA damage response. Inflammaging represents low-grade inflammation due to the dysregulation of innate and adaptive immune responses that occur with aging. Whether induced by infection, injury, or aging, immune dysregulation and chronic macrophage polarization contributes to cancer initiation through the production of proinflammatory chemokines/cytokines and genotoxins and by modulating immune surveillance. This review presents pre-clinical and clinical evidence for polarized macrophages as endogenous cellular carcinogens in the context of chronic inflammation, parainflammation, and inflammaging. Emerging strategies for cancer prevention, including small molecule inhibitors and probiotic approaches, that target macrophage function and phenotype are also discussed.

Diosmetin attenuate experimental ulcerative colitis in rats via suppression of NF-κB, TNF-α and IL-6 signalling pathways correlated with down-regulation of apoptotic events

Introduction

Ulcerative colitis (UC) is a chronic inflammation of colon in which the innermost tissue of colon and rectum develops deep-rooted inflammation. Diosmetin is the aglycone of the flavonoid glycoside diosmin, commonly found in citrus fruits. Therapeutically diosmetin is indicated to demonstrate anticancer, antimicrobial, antioxidant, oestrogenic and anti-inflammatory activity.

Methods

In this research, we studied the action of diosmetin on TNBS (2,4,6-trinitrobenzene sulfonic acid)-induced UC in rats. Male Wister rats were anesthetised with pentobarbital and TNBS introduced by performing an enema. Diosmetin treatment was provided through oral gavage for the next 28 days. Animals were sacrificed on the 29th day and colon tissues were collected for further examinations.

Results

Diosmetin treatment decreased colonic ulceration dramatically and decreased the percentage of inflammation in the colonic mucosa. Depletion of the TNBS assisted of superoxide dismutase and catalase was substantially restricted, while lipid peroxidation was recorded in the colonic tissue as malondialdehyde content was also decreased. After treatment with diosmetin, the occurrence of TNF-α, IL-6and NF-κB was considerably lowered and the number of apoptotic cells observed was significantly reduced.

Conclusion

Taken together, these observations demonstrated the potential of diosmetin against ulcer formation and development.

Inhibition of acetic acid-induced colitis in rats by new Pediococcus acidilactici strains, vitamin producers recovered from human gut microbiota

Our aim was to isolate, identify and characterize probiotic bacteria as vitamin producers in particular B2 and B9. 150 human fecal samples were collected and used for isolation of vitamin producers—probiotics. 49 isolates were chosen for screening their genome by PCR for the presence of riboflavin and folic acid genes. As a result, three isolates were selected and their production of the B2 and B9 were confirmed by HPLC. The three isolates were identified on species level by sequencing their 16S rRNA gene which showed 100% identical to strains of Pediococcus acidilactici. Thus, they were named as P. acidilactici WNYM01, P. acidilactici WNYM02, P. acidilactici WNYM03 and submitted to the Genbank database with accession numbers. They met the probiotic criteria by expressing 90–95% survival rate at pH (2.0–9.0) and bile salt up to 2% for 3 h in addition to their antimicrobial activity against gram positive and negative microorganisms. They also showed no hemolytic activity and common pattern for antibiotic susceptibility. Our three strains were tested individually or in mixture in vivo on rat colitis model compared to ulcerative group. The strains were administrated orally to rats in daily dose containing CFU 10⁹ for 14 days then followed by induction of colitis using acetic acid then the oral administration was continued for more four days. The histology results, the anti-inflammatory and anti-oxidative stress biomarkers showed the protective role of the strains compared to the ulcerative group. As a conclusion, we introduce novel three probiotic candidates for pharmaceutical preparations and health applications.

Healing effects of Cornus mas L. in experimentally induced ulcerative colitis in rats: From ethnobotany to pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The ethnobotanical studies conducted in Turkey and other countries have revealed that Cornus mas L., from the family Cornaceae have been used against stomachache, diarrhea and colitis.

AIM OF THE STUDY

The objective the present study is to determine the possible activity of C. mas in experimentally induced ulcerative colitis in rats and to identify its phytochemical feature.

MATERIALS AND METHODS

2,4,6-Trinitrobenzene sulfonic acid-induced colitis model was induced in rats. The rats were orally treated with different doses (50, 100, 200 and 400 mg/kg) of C. mas 80% methanol extract for 14 days. Increase in body weight, consumed amount of feed, form of the stool, presence of rectal prolapse were followed every day. At the end of the experiment, colon tissues were removed and wet weights for each animal were measured and colon damages were scored. Total antioxidant and total oxidant status, cytokine (TNF-α and IL-1β) and protein levels of colon tissues were evaluated and histopathological analyses were carried out. After the detection of the effective dose as 400 mg/kg, the aqueous methanol extract was fractionated by using liquid-liquid fractionation technique and the sub-extracts were also tested for in vivo biological activities. High Performance Liquid Chromatography analyses were conducted to determine the phytochemical profile of the active crude extract and n-butanol sub-extract.

RESULTS

Amount of feed consumed per day and increase in body weight were the lowest in the control group, while those values were determined to be the highest in 80% methanol extract (at 400 mg/kg dose), n-butanol sub-extract and reference groups. Following colitis induction, it was determined that the fecal form was yellow-slippery in all groups and returned to normal after the treatment with C. mas extracts. Rectal prolapse score was less in the extract (400 mg/kg) and n-butanol sub-extract treated groups. Total antioxidant, total oxidant status, cytokine and protein levels were found to be in parallel with macroscopic findings. 80% methanol extract (400 mg/kg) and n-butanol sub-extract provided the best healing according to the wet weight measurements and colon damage scoring performed on the removed colon tissues. These findings supported the results of histopathological analysis. According to the chromatographic analysis, ellagic acid was determined in both extracts and its amount was quantified.

CONCLUSIONS

The present study has verified the ethnomedical use of C. mas for the treatment of ulcerative colitis.

Acetic Acid-Induced Ulcerative Colitis in Sprague Dawley Rats Is Suppressed by Hydroethanolic Extract of Cordia vignei Leaves through Reduced Serum Levels of TNF-α and IL-6

BACKGROUND

Ulcerative colitis (UC) is a recurrent inflammatory bowel disease (IBD) that causes long-lasting inflammation on the innermost lining of the colon and rectum. Leaf decoctions of Cordia vignei have been used in traditional medicine either alone or in combination with other plant preparations to treat the disease.

AIM

In this study, we investigated the effect of hydroethanolic extract of Cordia vignei have been used in traditional medicine either alone or in combination with other plant preparations to treat the disease.

METHOD

Male Sprague Dawley rats received oral treatment of either saline (10 ml/kg), sulfasalazine (500 mg/kg), or CVE (30-300 mg/kg) daily for 7 days. On day 4, colitis was induced by a single intrarectal administration of 500 μl of acetic acid (4% v/v/.

RESULTS

CVE significantly (P < 0.05) prevented colonic ulceration and reduced the inflammatory score. Serum levels of TNF-α and IL-6 were significantly reduced. Depletion of superoxide dismutase (SOD) and catalase (CAT) activities by acetic acid was significantly inhibited while lipid peroxidation indexed as malondialdehyde (MDA) level in the colon was reduced. However, loss of body weight was not significantly affected by treatment with CVE.

CONCLUSION

This data suggest that CVE has a potential antiulcerative effect.

Bisphosphonates Zometa and Fosamax Synergize with Metformin to Prevent AOM-Induced Colon Cancer in F344 Rat Model

Recent observational studies suggest that bisphosphonates (BP) and antidiabetic drugs are associated with colorectal cancer risk reduction. Hence, we evaluated the colorectal cancer preventive effects of BPs (zometa and fosamax), individually and when combined with metformin, in azoxymethane-induced rat colon cancer model. Rat (30/group) were randomized and treated subcutaneously with azoxymethane to induce colorectal cancer. Dietary intervention with zometa or fosamax (0, 20, or 100 ppm) or metformin (1,000 ppm) or the combinations (zometa/fosamax 20 ppm plus metformin 1,000 ppm) began 4 weeks after azoxymethane treatment, at premalignant lesions stage. Rats were killed 40 weeks post drug intervention to assess colorectal cancer preventive efficacy. Dietary zometa (20 ppm) inhibited noninvasive adenocarcinomas multiplicity by 37% (P < 0.03) when compared with control diet fed group. Fosamax at 20 ppm and 100 ppm significantly reduced adenocarcinoma incidence (P < 0.005) and inhibited the noninvasive adenocarcinoma multiplicities by 43.8% (P < 0.009) and 60.8% (P < 0.004), respectively, compared with the group fed control diet. At 1,000 ppm dose, metformin failed to suppress colon adenocarcinoma formation. However, the lower dose combinations of zometa or fosamax with metformin resulted in significant inhibition of noninvasive adenocarcinoma by 48% (P < 0.006) and 64% (P < 0.0002), and invasive adenocarcinoma by 49% (P < 0.0005) and 38% (P < 0.006), respectively. Biomarker analysis of combination drug-treated tumors showed a decrease in cell proliferation with increased apoptosis when compared with untreated tumors. Overall, our results suggest that the combination of low doses of zometa or fosamax with metformin showed synergistic effect and significantly inhibited colon adenocarcinoma incidence and multiplicity.

Pharmacology of bisphosphonates in pain

The treatment of pain, in particular, chronic pain, remains a clinical challenge. This is particularly true for pain associated with severe or rare conditions, such as bone cancer pain, vulvodynia, or complex regional pain syndrome. Over the recent years, there is an increasing interest in the potential of bisphosphonates in the treatment of pain, although there are few papers describing antinociceptive and anti-hypersensitizing effects of bisphosphonates in various animal models of pain. There is also increasing evidence for clinical efficacy of bisphosphonates in chronic pain states, although the number of well-controlled studies is still limited. However, the mechanisms underlying the analgesic effects of bisphosphonates are still largely elusive. This review provides an overview of preclinical and clinical studies of bisphosphonates in pain and discusses various pharmacological mechanisms that have been postulated to explain their analgesic effects. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

Molecular pathways driving disease-specific alterations of intestinal epithelial cells

Due to the fact that chronic inflammation as well as tumorigenesis in the gut is crucially impacted by the fate of intestinal epithelial cells, our article provides a comprehensive overview of the composition, function, regulation and homeostasis of the gut epithelium. In particular, we focus on those aspects which were found to be altered in the context of inflammatory bowel diseases or colorectal cancer and also discuss potential molecular targets for a disease-specific therapeutic intervention.

The Bisphosphonate Pamidronate is an Intestinal Antiinflammatory Agent in Rat and Mouse Experimental Colitis

BACKGROUND

Statins have antiinflammatory effects at the cardiovascular level because of inhibition of prenylation, which also probably underlies their therapeutic effects in preclinical models of inflammatory bowel disease. Another inhibitor of prenylation, namely alendronate, reduces colitis in rodents. In this study, we aim to explore the therapeutic potential of second-generation, nitrogen-containing bisphosphonates in 3 preclinical models of colitis.

METHODS

The trinitrobenzenesulfonic acid and dextran sulfate sodium models of rat colitis and the adoptive lymphocyte transfer model of colitis in mice were used. Pamidronate, alendronate, and ibandronate were tested. Treatments were administered in equimolar doses through the oral or intraperitoneal route. The effect of pamidronate on prenylation and cytokine release was assessed in vivo and in vitro.

RESULTS

Pretreatment with pamidronate, but not with ibandronate or alendronate, improves chemically induced trinitrobenzenesulfonic acid and dextran sulfate sodium colitis in rats. Moreover, this beneficial effect is extended to lymphocyte transfer colitis. Pamidronate has no effect on intestinal epithelial cells in vitro in terms of cytokine/chemokine release, but enhances IFN-γ, IL-6, and IL-10 production by T cells in coculture. Pamidronate also exerts a direct immunomodulatory effect on T cells, favoring Th1 differentiation and impairing Th17 polarization.

CONCLUSIONS

Pamidronate presents antiinflammatory and immunomodulatory properties in 3 different models of experimental colitis in rodents. This effect requires oral administration and may involve T cells in the gut mucosa, although the exact mechanism is unclear.

Oral bisphosphonates and colon cancer: an update

Bisphosphonates (BPs) are widely used as the main treatment for osteoporosis. In vitro and animal studies suggest that use of BPs may have a potential for colorectal cancer (CRC) prevention. Safety and efficacy in terms of osteoporosis prevention have only been evaluated in randomized controlled trials (RCTs) of relatively short duration (3-5 years), with smaller extension studies. The evidence for a benefit beyond 5 years is limited and intake of BPs has not shown any relationship with CRC in intervention studies. Observational studies and meta-analysis have shown unchanged or decreased risk of CRC. BPs used for treatment and prevention of osteoporosis should not be applied for prevention of CRC in clinical practice.

Managing osteoporosis in ulcerative colitis: something new?

The authors revise the latest evidence in the literature regarding managing of osteoporosis in ulcerative colitis (UC), paying particular attention to the latest tendency of the research concerning the management of bone damage in the patient affected by UC. It is wise to assess vitamin D status in ulcerative colitis patients to recognize who is predisposed to low levels of vitamin D, whose deficiency has to be treated with oral or parenteral vitamin D supplementation. An adequate dietary calcium intake or supplementation and physical activity, if possible, should be guaranteed. Osteoporotic risk factors, such as smoking and excessive alcohol intake, must be avoided. Steroid has to be prescribed at the lowest possible dosage and for the shortest possible time. Moreover, conditions favoring falling have to been minimized, like carpets, low illumination, sedatives assumption, vitamin D deficiency. It is advisable to assess the fracture risk in all UC patient by the fracture assessment risk tool (FRAX(®) tool), that calculates the ten years risk of fracture for the population aged from 40 to 90 years in many countries of the world. A high risk value could indicate the necessity of treatment, whereas a low risk value suggests a follow-up only. An intermediate risk supports the decision to prescribe bone mineral density (BMD) assessment and a subsequent patient revaluation for treatment. Dual energy X-ray absorptiometry bone densitometry can be used not only for BMD measurement, but also to collect data about bone quality by the means of trabecular bone score and hip structural analysis assessment. These two indices could represent a method of interesting perspectives in evaluating bone status in patients affected by diseases like UC, which may present an impairment of bone quality as well as of bone quantity. In literature there is no strong evidence for instituting pharmacological therapy of bone impairment in UC patients for clinical indications other than those that are also applied to the patients with osteoporosis. Therefore, a reasonable advice is to consider pharmacological treatment for osteoporosis in those UC patients who already present fragility fractures, which bring a high risk of subsequent fractures. Therapy has also to be considered in patients with a high risk of fracture even if it did not yet happen, and particularly when they had long periods of corticosteroid therapy or cumulative high dosages. In patients without fragility fractures or steroid treatment, a medical decision about treatment could be guided by the FRAX tool to determine the intervention threshold. Among drugs for osteoporosis treatment, the bisphosphonates are the most studied ones, with the best and longest evidence of efficacy and safety. Despite this, several questions are still open, such as the duration of treatment, the necessity to discontinue it, the indication of therapy in young patients, particularly in those without previous fractures. Further, it has to be mentioned that a long-term bisphosphonates use in primary osteoporosis has been associated with an increased incidence of dramatic side-effects, even if uncommon, like osteonecrosis of the jaw and atypical sub-trochanteric and diaphyseal femoral fractures. UC is a long-lasting disease and the majority of patients is relatively young. In this scenario primary prevention of fragility fracture is the best cost-effective strategy. Vitamin D supplementation, adequate calcium intake, suitable physical activity (when possible), removing of risk factors for osteoporosis like smoking, and avoiding falling are the best medical acts.

Alendronate attenuates eosinophilic airway inflammation associated with suppression of Th2 cytokines, Th17 cytokines, and eotaxin-2

Bisphosphonates (BPs) have been widely used to treat osteoporosis. They act by inhibiting farnesyl diphosphate synthase in the mevalonate pathway. This resembles the action of statins, whose immune-modulating effect has recently been highlighted. In contrast, the effect of BPs on immune responses has not been elucidated well. In this study, we examined the effect of alendronate (ALN), a nitrogen-containing BP, on allergic airway inflammation in a mouse model. BALB/c mice were sensitized twice with OVA and challenged three times with nebulized OVA to induce eosinophilic airway inflammation. ALN was administered by an intragastric tube before each inhalation. ALN strongly suppressed airway eosinophilia and Th2, as well as Th17 cytokine production in the lung. ALN also attenuated eotaxin-2 production in the lung. Immunohistochemistry demonstrated that the major cell source of eotaxin-2 was peribronchial/perivascular macrophages, and flow cytometrical studies confirmed that ALN decreased eotaxin-2 expression in these macrophages. Furthermore, ALN attenuated eotaxin-2 production from mouse pleural macrophages and human monocyte/macrophage-like THP-1 cells in vitro. These results suggest that ALN suppressed Ag-induced airway responses in the mouse model. The suppression of eotaxin-2 production from macrophages appears to be one of ALN's immunomodulatory effects, whereas the mechanism by which ALN suppressed Th2 and Th17 responses could not be fully elucidated in this study. Although a clinical study should be conducted, ALN could be a novel therapeutic option for asthma.

Involvement of 5HT3 Receptors in Anti-Inflammatory Effects of Tropisetron on Experimental TNBS-Induced Colitis in Rat

INTRODUCTION

There is a pressing need for research leading to the development of new effective drugs with lower side effects and more efficacy for treating inflammatory bowel disease (IBD). The analgesic and anti-inflammatory properties of 5-Hydroxytryptamine (5-HT)-3 receptor antagonists have been shown in in vivo and in vitro studies. The present study was designed to investigate the effects of tropisetron, a 5-HT3 receptor antagonist, on an immune-based animal model of IBD.

METHODS

In the present study, the trinitrobenzenesulfonic acid (TNBS) model of colitis in the rat was used. Two hours after induction of colitis in rats, tropisetron (2 mg/kg), dexamethasone (1 mg/kg), meta-chlorophenylbiguanide (mCPBG, 5 mg/kg), a 5-HT3 receptor agonist, or tropisetron + mCPBG were intraperitoneally (i.p.) administrated for 6 days. Animals were then sacrificed; macroscopic, histological, biochemical (myeloperoxidase [MPO]) assessments and ELISA test (tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta) were performed on distal colon samples.

RESULTS

Tropisetron or dexamethasone treatment significantly reduced macroscopic and microscopic colonic damages. In addition, a significant reduction in MPO activity and colonic levels of inflammatory cytokines was seen. The beneficial effects of tropisetron were antagonized by concurrent administration of mCPBG.

CONCLUSION

The present study indicates that the protective effects of tropisetron on TNBS-induced colitis can be mediated by 5-HT3 receptors.

Bisphosphonates are associated with reduced risk of colorectal cancer: a systematic review and meta-analysis

BACKGROUND & AIMS

Colorectal cancer (CRC) is the third most common cancer worldwide. Several preclinical and observational studies have shown that bisphosphonates may have chemopreventive effects against CRC. We performed a systematic review and meta-analysis of all studies evaluating the effect of bisphosphonates on the risk of CRC.

METHODS

We conducted a systematic search of Medline, Embase, and Web of Science through August 2012 and manually reviewed the literature. Studies were included if they met the following criteria: (1) evaluated and clearly defined exposure to bisphosphonates, (2) reported CRC outcomes, and (3) reported relative risks or odds ratio (OR) or provided sufficient data for their estimation. Summary OR estimates with 95% confidence intervals (CIs) were estimated using the random-effects model. Statistical heterogeneity was assessed with the Cochran's Q and I(2) statistic.

RESULTS

We analyzed data from 6 population-based observational studies reporting 20,001 cases of CRC in 392,106 patients. A meta-analysis of these studies showed a statistically significant 17% reduction in CRC incidence with bisphosphonate use (unadjusted OR, 0.83; 95% CI, 0.76-0.90), with borderline heterogeneity across studies (Cochran's Q, P = .16; I(2) = 37%). This effect persisted after correcting for multiple covariates in individual studies (adjusted OR, 0.85; 95% CI, 0.74-0.98). When the analysis was restricted to women only, use of bisphosphonates was associated with a 16% reduction in CRC incidence, which bordered on statistical significance (n = 5 studies; adjusted OR, 0.84; 95% CI, 0.70-1.01). This chemopreventive effect of bisphosphonates was observed for proximal and distal colon cancers, as well as rectal cancer, independently.

CONCLUSIONS

Based on meta-analysis, bisphosphonate use is associated with a modest, but statistically significant, reduction in CRC risk.

Reduced colon cancer incidence and mortality in postmenopausal women treated with an oral bisphosphonate--Danish National Register Based Cohort Study

In this Danish national register-based cohort study, we examined the effects of alendronate on the development of colon cancers and survival. The incidence of colon cancer and mortality rate, once colon cancer had been diagnosed, were lower in patients treated with alendronate, posing the question whether alendronate acts as chemopreventive.

INTRODUCTION

When bisphosphonates are given by mouth, around 99% remains non-absorbed in the intestine. Based on their biochemical actions, we predicted that oral bisphosphonates might prevent colon cancers.

METHODS

This is a Danish national register-based cohort study. We identified 30,606 women aged 50+, mean age 71.9 years, who had not previously taken treatments for osteoporosis, who began to take alendronate in 1996-2005, and assigned 124,424 individually age- and gender-matched control subjects. The main outcome measure was colorectal cancers incidence and post-diagnosis survival in patients taking oral alendronate for osteoporosis.

RESULTS

Cox proportional hazards analysis of death due to colon cancer showed lower risk in alendronate users, crude hazard ratio (HR) 0.69 (95% CI 0.59-0.81) with an adjusted HR of 0.62 (95% CI 0.52-0.72). The reduction in risk comprised both a lower incidence of colon cancer-adjusted HR 0.69 (95% CI 0.60-0.79) and a lower mortality once colon cancer had been diagnosed, adjusted HR 0.82 (95% CI 0.70-0.97). Weekly alendronate was associated with a greater risk reduction than daily alendronate. The main findings were unaffected by excluding patients from the analysis who had pulmonary disease, a major co-morbid condition in users of alendronate and an important cause of death.

CONCLUSIONS

The risk of overall deaths from cancer and in particular death caused by colon cancer was significantly and substantially decreased (40%) in patients treated with alendronate, with survival curves deviating progressively after 2 years. Also, the incidence of colon cancer was lower in those patients.

Potential therapeutic effects of oral bisphosphonates on the intestine

Bisphosphonates are the principal drugs prescribed for the prevention of osteoporotic fractures. They are bone specific but poorly absorbed. In oral formulations, almost 99% of the administered dose remains within the intestinal tract and reaches the small and large bowel. Although the nitrogen-containing bisphosphonates can irritate the distal esophageal/gastric mucosa, they improve drug-induced colitis in animal models and exhibit antitumor properties on intestinal cells in vitro. Several recent epidemiological studies provide evidence of a reduced risk of colorectal cancer in osteoporotic patients treated with oral bisphosphonates, notably alendronate. In this review, we will explore the possible mechanisms of action underlying these effects and raise the question of whether these agents might be used in the chemoprophylaxis against colorectal cancer.

Preventive Therapy of Experimental Colitis with Selected iron Chelators and Anti-oxidants

OBJECTIVES

Iron chelators, such as maltol and kojic acid, have antioxidant and anti-inflammatory properties. They may have beneficial effects on inflammatory bowel disease (IBD) because iron can develop and aggravate inflammation in IBD. In the present study, the effect of selected iron chelators and anti-oxidants were evaluated on a model of trinitrobenzene sulfonic acid (TNBS)-induced colitis.

METHODS

Colitis was induced with instillation of 75 mg/kg TNBS in 0.25 ml ethanol 50% via the anus in fasted male Wistar rats. The animals were assigned randomly to 12 groups (n = 6) and treated once daily, started 2 hours before colitis induction, with normal saline (5 ml/kg), maltol (70, 140, 280 mg/kg), kojic acid (75, 150, 300 mg/kg), vitamin E (400 mg/kg), deferiprone (L1) (150 mg/kg) and prednisolone (4 mg/kg) orally and deferoxamine (50 mg/kg) intraperitoneally for 5 days. In the sixth day, rats were scarified and colon tissues were assessed macroscopically and pathologically.

RESULTS

Maltol (280 mg/kg) was able to reduce colon weight / length ratio, ulcer index and total colitis index similar to prednisolone, deferoxamine and deferiprone as positive controls. However, kojic acid and vitamin E could not significantly alleviate macroscopic and/or pathologic features of inflammation in comparison to normal saline.

CONCLUSIONS

Maltol with the highest test dose was capable to protect against experimentally induced colitis. Kojic acid and vitamin E were not effective in this animal model of colon inflammation. More detailed studies are warranted to explore the mechanisms involved in anti-colitic property of maltol and to explain ineffectiveness of kojic acid and vitamin E.

Anti-inflammatory effect of ondansetron through 5-HT3 receptors on TNBS-induced colitis in rat

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the intestinal tract whose etiology has not yet been fully elucidated. Available medicines for treatment of IBD are not universally effective and result in marked deleterious effects. This challenge has thus heightened the need for research in order to adopt new therapeutic approaches for the treatment of IBD. 5-HT3 receptor antagonists have shown analgesic and anti-inflammatory properties in vitro and in vivo. Our aim was to investigate the effect of ondansetron, 5-HT3 receptor antagonist, in an immune-based animal model of IBD, trinitrobenzene sulfonic acid (TNBS)-induced rat colitis and probable involvement of 5-HT3 receptors. Two hours after induction of colitis (instillation of 50 mg/kg of TNBS dissolved in 0.25 ml of ethanol 50 % v/v) to male Wistar rats, ondansetron (2 mg/kg), dexamethasone (1 mg/kg), meta-chlorophenylbiguanide (mCPBG, 5 mg/kg), a 5-HT3 receptor agonist, or ondansetron + mCPBG were administrated intraperitoneally (ip) and continued daily for six days. The animals were sacrificed and distal colons were assessed macroscopically, histologically and biochemically [myeloperoxidase (MPO), tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta]. Ondansetron and dexamethasone resulted in a decrease in macroscopic and microscopic colonic damage significantly. In addition a dramatic reduction in MPO activity and colonic levels of inflammatory cytokines were seen. The protective effects of ondansetron were antagonized by concurrent administration of mCPBG. Our data suggests that the beneficial effects of ondansetron in TNBS-induced colitis could be mediated by 5-HT3 receptors.

Does Cisapride, as a 5HT(4) Receptor Agonist, Aggravate the Severity of TNBS-Induced Colitis in Rat?

There is a pressing need for research that will lead to the reveal of targets designed to analyse the possible pathways for the treatment of IBD. Because of the probable involvement of serotonin in inflammatory conditions of intestine and the important role of 5HT(4) receptors in GI function, the investigation of the role of 5HT(4) receptors in the pathogenesis of IBD will be interesting. The aim of this study was to investigate the effects of cisapride, a 5HT(4) receptor agonist, in trinitrobenzenesulfonic-acid-(TNBS) induced rat colitis. Two hours subsequent to induction of colitis using TNBS in rats, cisapride (2 mg/kg, intraperitoneally (i.p); 4 mg/kg, orally (p.o)) and dexamethasone (1 mg/kg, i.p; 2 mg/kg, p.o) were administrated for 6 days. Animals were thereafter euthanized; macroscopic, histological, and biochemical assessments and ELISA test were carried out on distal colon samples. Our data showed that dexamethasone treatment (i.p, p.o) significantly decreased macroscopic and microscopic damage and also biochemical markers, but there were no significant differences in aforementioned parameters between cisapride (i.p or p.o) and TNBS-treated rats. It can be deduced that because the severity of colitis produced by TNBS is massive (through various pathways), cisapride could not bring about more colitis damages through 5HT(4) receptors. Based on the present study further researches are required for investigating the exact roles of 5HT(4) receptors in the pathogenesis of ulcerative colitis.

Validation and optimization of experimental colitis induction in rats using 2, 4, 6-trinitrobenzene sulfonic acid

Trinitrobenzene sulfonic acid (TNBS)-induced colitis is one of the most common methods for studying inflammatory bowel disease in animal models. Several factors may, however, affect its reproducibility, rate of animal mortality, and macroscopic and histopathological outcomes. Our aim was to validate the main contributing factors to this method and compare the effects of different reference drugs upon remission of resultant colon injuries. TNBS was dissolved in 0.25 ml of ethanol (50% v/v) and instilled (25, 50, 100 and 150 mg/kg) intracolonically to the male Wistar rats. After determination of optimum dose of TNBS in male rats and assessment of this dose in female rats, they were treated with reference drugs including dexamethasone [1 mg/kg, intraperitoneally (i.p.) and 2 mg/kg, orally (p.o.)], Asacol (mesalazine, 100 mg/kg, p.o.; 150 mg/kg, enema) and hydrocortisone acetate (20 mg/kg, i.p.; 20 mg/kg, enema) which started 2 h after colitis induction and continued daily for 6 consecutive days. Thereafter, macroscopic and microscopic parameters and clinical features were assessed and compared in different groups. We found that the optimum dose of TNBS for the reproducibility of colonic damage with the least mortality rate was 50 mg/kg. Amongst studied reference drugs, hydrocortisone acetate (i.p.), dexamethasone (i.p. and p.o.) and Asacol (p.o.) significantly diminished the severity of macroscopic and microscopic injuries and could be considered effective for experimental colitis studies in rats . Our findings suggest that optimization of TNBS dose is essential for induction of colitis under the laboratory conditions; and gender exerts no impact upon macroscopic and histological characteristics of TNBS-induced colitis in rats. Furthermore, the enema forms of hydrocortisone and Asacol are not appropriate reference drugs.

Bovine glycomacropeptide has intestinal antiinflammatory effects in rats with dextran sulfate-induced colitis

Milk κ-casein-derived bovine glycomacropeptide (GMP) has immunomodulatory and bacterial toxin-binding effects, and it has been shown to exert intestinal antiinflammatory activity in the trinitrobenzenesulfonic acid-induced model of colitis. However, its mechanism of action is not well characterized, and it is not known whether GMP is effective in other experimental models. The intestinal antiinflammatory activity of GMP was assessed in the dextran sulfate sodium (DSS)-induced model of rat colitis. DSS was applied at a starting concentration of 5% (wt:v) in drinking water and adjusted when the disease activity index (DAI) increased substantially for 10 d. There were 3 experimental groups: control (no inflammation), DSS, and GMP (GMP-treated rats with DSS-induced colitis). GMP pretreatment (500 mg · kg(-1) · d(-1), starting 2 d before DSS treatment) reduced the DAI by 60% and lowered the colonic damage score by 44% (P < 0.05). GMP fully normalized the colonic expression of interleukin (IL) 1β, IL17, IL23, IL6, transforming growth factor β, IL10, and Foxp3 as assessed by quantitative RT-PCR. The production of interferon-γ by mesenteric lymph node cells ex vivo was also normalized by GMP treatment. In contrast, GMP did not change colonic thickening, myeloperoxidase, cyclooxygenase 2, or alkaline phosphatase. Histology analysis showed better preservation of the epithelium and attenuated infiltration and submucosal thickening in rats treated with GMP. We conclude that GMP exerts intestinal antiinflammatory activity in this model, which may be primarily related to actions on Th1 and Th17 lymphocytes and perhaps macrophages.

Mouse macrophages primed with alendronate down-regulate monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) production in response to Toll-like receptor (TLR) 2 and TLR4 agonist via Smad3 activation

Alendronate is one of the nitrogen-containing bisphosphonates (NBPs) used as anti-bone resorptive drugs. However, NBPs have inflammatory side effects including osteomyelitis and osteonecrosis of the jaw. In the present study, we examined the effects of alendronate on chemokine production by the macrophage-like cell line, J774.1, when incubated with Pam(3)CSK(4) (a Toll-like receptor (TLR) 2 agonist) and Lipid A (a TLR4 agonist). Pretreatment of J774.1 cells with alendronate decreased the production of TLR ligand-induced monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) but did not influence nuclear factor-kappaB (NF-kappaB) activation. While this agent induced caspase-8 activation, a caspase-8 inhibitor did not affect the decrease in MCP-1 production by alendronate and TLR ligands. Thus, the alendronate-mediated decrease in chemokine production was independent of NF-kappaB and caspase-8 activation. Although transforming growth factor-beta1 (TGF-beta1) is known to inhibit chemokine production by various cell types via Smad3 activation, pretreatment with alendronate did not increase TGF-beta1 production by J774.1 cells incubated in the presence or absence of TLR ligands. However, alendronate directly activated Smad3. These results suggest that by down-regulating MCP-1 and MIP-1alpha production via Smad3, long-term use of alendronate might inhibit normal activation and migration of osteoclasts and cause osteonecrosis.

Alendronate augments interleukin-1beta release from macrophages infected with periodontal pathogenic bacteria through activation of caspase-1

Nitrogen-containing bisphosphonates (NBPs) are anti-bone-resorptive drugs with inflammatory side effects that include osteomyelitis and osteonecrosis of the jaw. Oral bacteria have been considered to be a trigger for these NBP-associated jaw bone diseases. The present study examined the effects of alendronate (a typical NBP) and clodronate (a non-NBP) on the production of proinflammatory cytokines by macrophages infected with Porphyromonas gingivalis and Tannerella forsythia, which are important pathogens of periodontal diseases. Pretreatment with alendronate augmented IL-1beta, but not TNFalpha, production by macrophages infected with P. gingivalis or T. forsythia. This augmentation of IL-1beta production was inhibited by clodronate. Furthermore, caspase-1, a promoter of IL-1beta production, was activated by treatment with alendronate, and caspase-1 inhibitor reduced the production of IL-1beta induced by alendronate and P. gingivalis. These results suggest that NBPs augment periodontal pathogenic bacteria-induced IL-1beta release via caspase-1 activation, and this phenomenon may contribute to the development of NBP-associated inflammatory side effects including jaw osteomyelitis. Co-treatment with clodronate may prevent and/or reduce these inflammatory effects induced by NBPs.