In vitro effects of oxpentifylline on inflammatory cytokine release in patients with inflammatory bowel disease

Cyclic adenosine 3', 5'-monophosphate (cAMP) signaling is a crucial therapeutic target for ulcerative colitis

The pathogenesis of ulcerative colitis (UC), a chronic intestine inflammatory disease primarily affecting adolescents, remains uncertain. Contemporary studies suggest that a confluence of elements, including genetic predispositions, environmental catalysts, dysregulated immune responses, and disturbances in the gut microbiome, are instrumental in the initiation and advancement of UC. Among them, inflammatory activation and mucosal barrier damage caused by abnormal immune regulation are essential links in the development of UC. The impairment of the mucosal barrier is intricately linked to the interplay of various cellular mechanisms, including oxidative stress, autophagy, and programmed cell death. An extensive corpus of research has elucidated that level of cyclic adenosine 3',5'-monophosphate (cAMP) undergo modifications in the midst of inflammation and participate in a diverse array of cellular operations that mitigate inflammation and the impairment of the mucosal barrier. Consequently, a plethora of pharmacological agents are currently under development, with some advancing through clinical trials, and are anticipated to garner approval as novel therapeutics. In summary, cAMP exerts a crucial influence on the onset and progression of UC, with fluctuations in its activity being intimately associated with the severity of the disease's manifestation. Significantly, this review unveils the paramount role of cAMP in the advancement of UC, offering a tactical approach for the clinical management of individuals afflicted with UC.

Combining Pentoxifylline With Vedolizumab for Crohn's Disease: Results of a Randomised, Placebo-controlled Pilot Study

BACKGROUND AND AIMS

The efficacy of current biologics may be limited by targeting only one pathway. Pentoxifylline [PTX] interferes with tumour necrosis factor [TNF] gene expression. We performed a randomised, placebo-controlled pilot study to determine if PTX plus vedolizumab [VDZ] in patients with Crohn's disease [CD] is safe and improves response compared with VDZ monotherapy.

METHODS

Thirty adult patients with active CD were randomised to VDZ/PTX or VDZ/placebo and followed for 24 weeks. Endoscopic activity and inflammatory cytokines were measured at baseline and Week 24. Descriptive statistics were used to determine estimates of effect.

RESULTS

Demographics were similar but baseline disease activity was higher in the VDZ/PTX group. There was no difference in clinical remission at Week 14 (60.0% vs 66.67%, odds ratio [OR] 0.76, 95% confidence interval [CI] 0.16, 3.51) or steroid-free clinical remission at Week 24 in patients receiving VDZ/PTX. Improved clinical response was noted in the VDZ/PTX group at Weeks 6, 14, and 24 [Week 6: 20% vs 6.67%, Week 14: 26.67% vs 6.67%, Week 24: 40% vs 20%]. The rate of endoscopic remission was similar between the groups [40% vs 33.33%], with a greater mean decrease in Simple Endoscopic Score-CD [SES-CD] and C-reactive protein [CRP] with VDZ/PTX [SES-CD -3.17 vs -0.15, CRP -5.56 vs 0.46]. An increase in serum TNF-α concentration was observed with VDZ/placebo group; PTX mitigated this effect. No serious adverse events occurred.

CONCLUSIONS

VDZ/PTX did not provide benefit over VDZ monotherapy in clinical or endoscopic remission but appeared to improve clinical response and was safe. These data should inform a fully powered study.

The Complexity and Multiplicity of the Specific cAMP Phosphodiesterase Family: PDE4, Open New Adapted Therapeutic Approaches

Cyclic nucleotides (cAMP, cGMP) play a major role in normal and pathologic signaling. Beyond receptors, cyclic nucleotide phosphodiesterases; (PDEs) rapidly convert the cyclic nucleotide in its respective 5'-nucleotide to control intracellular cAMP and/or cGMP levels to maintain a normal physiological state. However, in many pathologies, dysregulations of various PDEs (PDE1-PDE11) contribute mainly to organs and tissue failures related to uncontrolled phosphorylation cascade. Among these, PDE4 represents the greatest family, since it is constituted by 4 genes with multiple variants differently distributed at tissue, cellular and subcellular levels, allowing different fine-tuned regulations. Since the 1980s, pharmaceutical companies have developed PDE4 inhibitors (PDE4-I) to overcome cardiovascular diseases. Since, they have encountered many undesired problems, (emesis), they focused their research on other PDEs. Today, increases in the knowledge of complex PDE4 regulations in various tissues and pathologies, and the evolution in drug design, resulted in a renewal of PDE4-I development. The present review describes the recent PDE4-I development targeting cardiovascular diseases, obesity, diabetes, ulcerative colitis, and Crohn's disease, malignancies, fatty liver disease, osteoporosis, depression, as well as COVID-19. Today, the direct therapeutic approach of PDE4 is extended by developing allosteric inhibitors and protein/protein interactions allowing to act on the PDE interactome.

Development, optimization, and validation of Inflammatory Bowel Disease rat model using isotretinoin

BACKGROUND

and Purpose: Inflammatory Bowel Disease (IBD) is a persistent bio-psychological disorder with the absence of actual pathological reason. Association between IBD and isotretinoin has been reported by many human and in vitro studies. However, in this study, our focus is on finding the causal relationship between IBD and isotretinoin for the development of a new animal model.

METHODS

Twenty-eight Sprague Dawley rats were taken for this study and divided into five groups (i.e. Group 1: Normal control, Group 2: Standard IBD Model Group (Indomethacin treated), Group 3: Isotretinoin low dose (7 mg/kg), Group 4: Isotretinoin medium dose (35 mg/kg), Group 5: Isotretinoin high dose (70 mg/kg). The rats were treated according to assigned treatment and observed on different days to evaluate the severity of IBD with the help of symptomatical (nausea, diarrhea, stool consistency, etc.) activity, biochemical parameters, macroscopy, and histological analyses.

KEY RESULTS

During the entire study period, body weight, stool consistency and frequency of the animals had been observed daily. No significant reduction in body weight was observed between the disease induced and normal control animals; however, it was observed that the stool consistency of the animals became less (mucus in stool) day by day and stool frequency increased (frequent defecation) in the different isotretinoin groups compared to the control group. There was statistically significant increase in TBARS levels of isotretinoin low (p < 0.05), medium (p < 0.001) and high dose (p < 0.01) treated group was observed, as compared to control group. Similarly, statistically significant effects of isotretinoin on GSH level (p < 0.01), CAT activity (p < 0.01), and SOD (p < 0.01) were also observed. Increase in TNF-α levels found significantly higher in isotretinoin medium dose (35 mg/kg) treated group (p < 0.001) as compared with control group as well as standard IBD model group. All the three-isotretinoin treated groups (Isotretinoin low dose: p < 0.001; Isotretinoin medium dose: p < 0.001; Isotretinoin high dose: p < 0.001) depicted significant difference in macroscopic scores as compared with control group; these results are comparable with standard IBD model group. Histological analyses revealed that, among three-dose groups of isotretinoin, there was excessive amount of crypt abscesses, infiltration of inflammatory cells, and formation of ulceration observed in isotretinoin medium dose treated group.

CONCLUSION

As standard indomethacin treated group, isotretinoin also caused significant damage to intestinal mucosa, and form ulceration in gastrointestinal tract. Compared to control group, isotretinoin significantly worsens the disease condition, which were comparable to the indomethacin-treated group; however, isotretinoin at the dose of 35 mg/kg caused maximum severe damage to the intestinal mucosa.

Chitinases and Chitinase-Like Proteins as Therapeutic Targets in Inflammatory Diseases, with a Special Focus on Inflammatory Bowel Diseases

Chitinases belong to the evolutionarily conserved glycosyl hydrolase family 18 (GH18). They catalyze degradation of chitin to N-acetylglucosamine by hydrolysis of the β-(1-4)-glycosidic bonds. Although mammals do not synthesize chitin, they possess two enzymatically active chitinases, i.e., chitotriosidase (CHIT1) and acidic mammalian chitinase (AMCase), as well as several chitinase-like proteins (YKL-40, YKL-39, oviductin, and stabilin-interacting protein). The latter lack enzymatic activity but still display oligosaccharides-binding ability. The physiologic functions of chitinases are still unclear, but they have been shown to be involved in the pathogenesis of various human fibrotic and inflammatory disorders, particularly those of the lung (idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, sarcoidosis, and asthma) and the gastrointestinal tract (inflammatory bowel diseases (IBDs) and colon cancer). In this review, we summarize the current knowledge about chitinases, particularly in IBDs, and demonstrate that chitinases can serve as prognostic biomarkers of disease progression. Moreover, we suggest that the inhibition of chitinase activity may be considered as a novel therapeutic strategy for the treatment of IBDs.

Transcribed ultraconserved region (T-UCR) uc.261 expression is closely correlated with disease activity and intestinal permeability in Crohn's disease

OBJECTIVES

Transcribed ultraconserved region (T-UCR) uc.261 is reported to participate in intestinal mucosa barrier damage in Crohn's disease (CD). The aim of this study was to determine the association with disease activity and intestinal permeability.

METHODS

Uc.261 level in colon mucosa and Harvey-Bradshaw Index (HBI) were evaluated in 20 active CD patients. Uc.261 expression and transepithelial electrical resistance (TEER) were determined in Caco2 and T84 cells treated with tumor necrosis factor alpha (TNF-α), respectively. Body weight, disease activity index (DAI), colon length, histological index (HI), intestinal permeability to FITC-dextran, uc.261, and tight junction proteins (TJPs) levels were evaluated in BALB/C mice treated with saline enema, trinitrobenzene sulfonic acid (TNBS)/ethanol enema, and anti-TNF-α monoclonal antibody injection, respectively.

RESULTS

Uc.261 expression was overexpressed in CD patients, TNF-α treated cells, and colitis mice. Uc.261 expression was positively correlated with HBI (r = 0.582, p = 0.007) in CD patients, and positively correlated with TNF-α concentration and negatively correlated TEER in Caco2 and T84 cells (all p < 0.05). Furthermore, uc.261 was positively correlated with DAI (r = 0.824, p = 0.008), HI (r = 0.672, p = 0.021), and intestinal permeability (r = 0.636, p = 0.012), while negatively correlated with body weight (r = -0.574, p = 0.035), colon length (r = -0.866, p = 0.017), and TJP expression (all p < 0.05) in colitis mice.

CONCLUSIONS

Uc.261 expression was closely correlated with disease activity and intestinal permeability in CD. Anti-TNF-α treatment may play its role through suppressing uc.261 expression in colitis mice.

Total Glycosides of Peony Protects Against Inflammatory Bowel Disease by Regulating IL-23/IL-17 Axis and Th17/Treg Balance

Inflammatory bowel disease (IBD) is a group of autoimmune diseases, including ulcerative colitis and Crohn’s disease, characterized by nonspecific inflammation in the gut. Total glycoside of peony (TGP) has been widely used for treatment of autoimmune diseases because of its pharmacological effects. However, it is lack of depth in whether TGP regulate T helper 17 cell (Th17) / T regulatory cell (Treg) immune balance or interleukin 23 (IL-23) / IL-17 axis to achieve the goal of treating IBD. Hence, the aim of this study was to investigate the effects of TGP on experimental colitis mice and the related mechanisms. In the present study, we demonstrated that administration of TGP effectively attenuates colonic inflammation of TNBS-induced colitis mice, mainly reflected in significantly improved clinical parameters, reduced inflammatory response and myeloperoxidase (MPO) activity, even stronger systemic immune ability and effective improvement of Th17/Treg immune disorders. In addition, there was a stronger immunosuppressive ability in a positive cluster of differentiation 4 (CD4[Formula: see text]) T-lymphocytes from the TGP treated mouse colon, characterized by the inhibition of high levels of inflammatory factors and increased regulatory T cells. Importantly, high-dose TGP has similar therapeutic effects as salicylazosulfapyridine (SASP) on IBD treatment. The potential mechanisms might be, at least in part, related to the adjustment of imbalance of Th17/Treg cells and the inhibition of IL-23/IL17 inflammatory signal axis.

Ghrelin protects against contact dermatitis and psoriasiform skin inflammation by antagonizing TNF-α/NF-κB signaling pathways

Contact dermatitis and psoriasis are skin disorders caused by immune dysregulation, yet much remains unknown about their underlying mechanisms. Ghrelin, a recently discovered novel peptide and potential endogenous anti-inflammatory factor expressed in the epidermis, is involved in skin repair and disease. In this study, we investigated the expression pattern and therapeutic effect of ghrelin in both contact dermatitis and psoriasis mouse models induced by oxazolone (OXA) and imiquimod (IMQ), respectively, and in TNF-α-stimulated RAW264.7 macrophages, NHEKs and skin fibroblasts. Ghrelin expression was reduced in both the OXA-induced contact dermatitis and IMQ-induced psoriasis mouse models. Furthermore, treatment with ghrelin attenuated skin inflammation in both the contact dermatitis and psoriasis mouse models. Mice administered PBS after OXA- or IMQ-induced model generation exhibited typical skin inflammation, whereas ghrelin treatment in these mouse models substantially decreased the dermatitis phenotype. In addition, exogenous ghrelin attenuated the inflammatory reaction induced by TNF-α in RAW264.7 cells. Moreover, ghrelin administration limited activation of NF-κB signaling. In summary, ghrelin may represent a potential molecular target for the prevention and treatment of inflammatory skin diseases, including contact dermatitis and psoriasis.

Inhibitory effects of pentoxifylline on inflammation-related tumorigenesis in rat colon

Chronic inflammation in the colorectum increases the risk of colorectal cancer development. Pentoxifylline, a medicine used for improving the circulation, has been reported to inhibit TNF-α production and to ameliorate inflammatory bowel disease and non-alcoholic steatohepatitis. In this study, we investigated the effects of pentoxifylline on inflammation-related colon tumorigenesis in a rodent model using Kyoto APC delta rats, which have APC mutation and are susceptible to colon carcinogenesis. Male Kyoto APC delta rats were treated with azoxymethane and dextran sodium sulfate, and were subsequently administered water, with or without pentoxifylline. At the end of the experiment, the development of colorectal tumor was significantly inhibited in the pentoxifylline group. The pentoxifylline treatment also lowered the levels of oxidative stress markers and mRNAs of pro-inflammatory cytokines, including TNF-α and IL-6, in the colon mucosa. The PCNA labeling index and the inflammation score were also decreased in the colon of rats in the pentoxifylline -treated group. We also used an endoscopy to observe the tumor progression and inflammation in the colon of rats, revealing that inflammation grade was significantly lower in pentoxifylline-treated group at several points during the experiment. These findings suggest that pentoxifylline treatment might be useful for chemoprevention of inflammation-related colon cancer.

Pentoxifylline attenuates mucosal damage in an experimental model of rat colitis by modulating tissue biomarkers of inflammation, oxidative stress, and fibrosis

BACKGROUND/AIM

This study was designed to identify the effect of pentoxifylline on trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats.

MATERIALS AND METHODS

Forty-two female Wistar rats were randomly divided into 7 groups: group A, TNBS + intraperitoneal (IP) pentoxifylline; group B, TNBS + IP saline; group C, TNBS + intrarectal (IR) pentoxifylline; group D, TNBS + IR saline; group E, IP pentoxifylline + TNBS; group F, IP saline + TNBS; group G, IR saline. Pentoxifylline was given daily for 3 days before or 6 days after the induction of colitis. Rats were killed after 6 days.

RESULTS

IP and IR pentoxifylline similarly and significantly reduced damage and histopathological scores. Pentoxifylline attenuated the accumulation of malonyldialdehyde and transforming growth factor β1 and the activities of myeloperoxidase, matrix metalloproteinase-3, and tissue inhibitor of metalloproteinases-1, and it also restored superoxide dismutase activity. The IP route was more effective than the IR route in this regard. Administration of IP pentoxifylline before or after induction did not influence all parameters. Conclusions: Pentoxifylline showed a therapeutic effect in this experimental colitis model. IP administration seemed to be better. This effect may occur as a result of inhibition of oxidative stress and metalloproteinase activity.

Preventive Effects of Pentoxifylline on the Development of Colonic Premalignant Lesions in Obese and Diabetic Mice

Obesity and its related metabolic abnormalities, including enhanced oxidative stress and chronic inflammation, are closely related to colorectal tumorigenesis. Pentoxifylline (PTX), a methylxanthine derivative, has been reported to suppress the production of tumor necrosis factor (TNF)-α and possess anti-inflammatory properties. The present study investigated the effects of PTX on the development of carcinogen-induced colorectal premalignant lesions in obese and diabetic mice. Male C57BL/KsJ-db/db mice, which are severely obese and diabetic, were administered weekly subcutaneous injections of the colonic carcinogen azoxymethane (15 mg/kg body weight) for four weeks and then received drinking water containing 125 or 500 ppm PTX for eight weeks. At the time of sacrifice, PTX administration markedly suppressed the development of premalignant lesions in the colorectum. The levels of oxidative stress markers were significantly decreased in the PTX-treated group compared with those in the untreated control group. In PTX-administered mice, the mRNA expression levels of cyclooxygenase (COX)-2, interleukin (IL)-6, and TNF-α, and the number of proliferating cell nuclear antigen (PCNA)-positive cells in the colonic mucosa, were significantly reduced. These observations suggest that PTX attenuated chronic inflammation and oxidative stress, and prevented the development of colonic tumorigenesis in an obesity-related colon cancer model.

The effect of pentoxifylline and its metabolite-1 on inflammation and fibrosis in the TNBS model of colitis

TNBS-induced colitis has characteristics resembling human Crohn's disease including transmural inflammation, ulceration, and fibrosis. Current treatments target acute symptoms but do not necessarily prevent fibrotic complications of the disease. The aim of this study was to determine the effect of pentoxifylline and its primary metabolite (M-1) on fibrosis in the TNBS-induced colitis model. Myeloperoxidase activity and interleukin-18 are indicators of inflammation and were elevated in the TNBS model. The morphology damage score assesses colon damage and was also elevated in the TNBS model. Collagen as the indicator of fibrosis was quantified and visualized by the Sirius Red/Fast Green staining technique and collagen type I was assessed by Western analysis. Collagen was elevated in the TNBS-induced model. Pentoxifylline and M-1 treatment significantly attenuated colon damage and inflammation in TNBS-colitis (P<0.05). M-1 treatment significantly reduced the TNBS-induced increase in colon weight, colon thickness and total collagen content (P<0.05). Results suggest that pentoxifylline and M-1 inhibit intestinal fibrosis in this experimental model and may prove beneficial in the treatment of intestinal fibrosis associated with human Crohn's disease with the added benefit of inhibiting inflammation and ulceration. This is the first study to examine the effects of racemic M-1 in vivo and one of the few studies to examine the effect of drugs on both inflammation and fibrosis in an experimental model of colitis.

Wormwood (Artemisia absinthium) suppresses tumour necrosis factor alpha and accelerates healing in patients with Crohn's disease - A controlled clinical trial

Suppression of tumour necrosis factor alpha (TNF-alpha) and other interleukins by wormwood (Artemisia absinthium) extracts were reported recently in in vitro studies. The aim of the present study was to find out if this effect can be also be observed in Crohn's Disease (CD) patients where TNF-alpha appears to play an important role. In a controlled trial, 10 randomly selected patients suffering from CD were given in addition to their basic CD therapy 3x750mg dried powdered wormwood for 6 weeks. Ten patients, also randomly selected who met the inclusion criteria served as control group. Minimum score of 200 on Crohn's Disease Activity Index (CDAI) was required at baseline for inclusion in each group. Patients who received infliximab or similar were excluded from the trial. TNF-alpha level in serum were measured at baseline, and after three and six weeks. During this period all concomitant CD medications was maintained at the baseline dose levels. Average serum TNF-alpha level fell from 24.5+/-3.5pg/ml at baseline to 8.0+/-2.5pg/ml after six weeks. The corresponding levels in the control group were 25.7+/-4.6 (week 0), and 21.1+/-3.2 (week 6). On the clinical side, CDAI scores fell from 275+/-15 to below 175+/-12 in wormwood group with remission of symptoms in eight patients (CDAI score below 170 or reduction by 70 points), compared to only two in the placebo group (CDAI of placebo group 282+/-11 at baseline and 230+/-14 on week 6). IBDQ also reflected accelerated clinical response with wormwood. Of clinical significance were the findings that wormwood also improved mood of the CD patients, as reflected in Hamilton's Depression Scale. These findings provide a base to test wormwood in clinical conditions thought to be mediated by increased production of pro-inflammatory cytokines such as TNF-alpha.

A new agent for tumour necrosis factor-alpha inhibition: In vitro effects of dipyridamole in Crohn's disease

BACKGROUND

Tumour necrosis factor-alpha (TNF-alpha) plays a central role in inflammatory cascade in Crohn's disease (CD). Our study aims to investigate the in vitro effects of dipyridamole (DP) on the TNF-alpha and interleukin-10 (IL-10) production in the intestinal mononuclear cells of CD patients.

MATERIAL AND METHODS

Thirteen patients with CD and in 17 healthy individuals underwent colonoscopy and biopsy samples were taken. Cultured mononuclear cells were preincubated with DP1 (0.7 microg/ml), DP2 (1.25 microg/ml), methotrexate (MTX)1 (0.5 nmol/L) and MTX2 (1.5 nmol/L). These cells were then stimulated with lipopolysaccaride (LPS) and phytohemagglutinin (PHA). The levels of TNF-alpha and IL-10 in supernatants were measured with standard immunoassay monoclonal antibody method.

RESULTS

An appropriate cell culture could be obtained in 10 patients with CD and 12 healthy individuals. In LPS stimulated cells, MTX1 and MTX2 were superior to DP1 and DP2 in suppressing TNF-alpha in both groups. In PHA stimulated cells, while MTX1 was superior to DP1, MTX2 and DP2 had an equivalent effect in CD patients (p<0.05, p>0.05, respectively). In LPS-stimulated cells DP2 was significantly superior to MTX2 in increasing IL-10 levels in both groups (p<0.05). In PHA stimulated cells, DP1 and DP2 caused a higher increase in IL-10 levels compared with MTX1 and MTX2 in CD group (p<0.05).

CONCLUSIONS

Dipyridamole suppresses TNF-alpha similar with MTX. It seems to be superior to MTX in increasing IL-10 levels. Addition of DP to anti-TNF medications may create a synergy in cytokine modulation.

TNF-alpha modulates iNOS expression in an experimental rat model of indomethacin-induced jejunoileitis

Multiple mucosal immune factors, such as TNF-alpha and IL-1beta, are thought to be key mediators involved in inflammatory bowel disease. We evaluated the role of the pro-inflammatory cytokine TNF-alpha on nitric oxide synthase (NOS) expression in indomethacin-induced jejunoileitis in rats. Jejunoileitis was induced in rats with subcutaneous injections of indomethacin (7.5 mg/kg) 24 h apart for two consecutive days, and animals were randomized into four groups. Group 1 received only indomethacin. Group 2 was treated with a daily dose of phosphodiesterase (PDE) inhibitor (theophylline or pentoxifylline) by oral gavage for 2 days before and 4 days after indomethacin. Group 3 received a single dose of anti-TNF-alpha monoclonal antibody (TNF-Ab, IP) 30 min before indomethacin. Group 4 was treated with 1 h hyperbaric oxygenation (HBO(2)) for 5 days after indomethacin. Rats were sacrificed at 12 h or 4 days after final indomethacin injection. PDE inhibitor, TNF-Ab, or HBO(2) treatment significantly decreased indomethacin-induced ulceration, myeloperoxidase activity, and disease activity index. Although indomethacin significantly increased serum TNF-alpha and nitrate/nitrite (NOx) concentrations above control values at 12 h, inducible NOS (iNOS) expression was detected only at day 4. Serum IL-1beta levels did not change at 12 h but increased 4-fold after 4 days. Indomethacin had no effect on constitutive NOS. Treatment with PDE inhibitor, TNF-Ab, or HBO(2) significantly reduced serum/tissue TNF-alpha, IL-1beta, NOx, and iNOS expression. Our data show TNF-alpha plays an early pro-inflammatory role in indomethacin-induced jejunoileitis. Additionally, down-regulation of NOx by PDE inhibitors, TNF-Ab, or HBO(2) suggests that TNF-alpha modulates iNOS expression.

A novel drug interaction between the quinolone antibiotic ciprofloxacin and a chiral metabolite of pentoxifylline

Pentoxifylline (PTX), a methylxanthine derivative, is metabolized to seven compounds in vivo, with metabolites 1 and 5 possessing biologic activity. Metabolite-1 is a chiral molecule and its S-enantiomer is selectively formed during PTX metabolism in vivo. We have developed a reproducible method of synthesizing a racemic mixture of the chiral metabolite-1 (M-1) of PTX. In this study, we examined the kinetics of racemic M-1 in mice compared to PTX. An interaction between PTX and the quinolone antibiotic ciprofloxacin has been demonstrated. A goal of this study was to determine if a similar interaction occurs between ciprofloxacin and M-1 in vivo. M-1 and PTX had similar absorption and elimination rates. M-1 was rapidly converted to PTX, while very little PTX was converted to M-1 in vivo. The peak concentration of biologically active drug (PTX+M-1) was 36% higher when M-1 was administered compared to PTX. Combination of ciprofloxacin and PTX significantly increased serum concentrations of both PTX and M-1 (2-fold) compared to controls. The combination of M-1 and ciprofloxacin significantly increased serum concentration of M-1 (3-fold) and PTX (2-fold). The ciprofloxacin/M-1 combination produced a significantly higher sera concentration of bioactive drug compared to all other groups suggesting that this combination may enhance the anti-fibrogenic effect.

The role of TNFalpha in ulcerative colitis

Standard of care for ulcerative colitis involves long-term pharmacotherapy or colectomy. Approximately 20% to 30% of patients eventually require a colectomy because patients either do not respond or cannot tolerate the currently available pharmacotherapies. Advances in our knowledge of the pathophysiology of ulcerative colitis have highlighted the importance of cytokines such as tumor necrosis factor alpha (TNFalpha) in the inflammatory process. TNFalpha is a proinflammatory mediator that plays an integral role in the pathogenesis of inflammatory bowel disease. In addition, mounting evidence indicates a genetic association between TNFalpha and ulcerative colitis. Furthermore, increased TNFalpha levels have been demonstrated in studies of patients with ulcerative colitis. TNFalpha is likely an important component in the pathophysiology of ulcerative colitis, and thus agents targeting TNFalpha in ulcerative colitis have been studied. Recent randomized controlled trials have confirmed that biologic anti-TNFalpha therapy is effective in ulcerative colitis. Soluble TNFalpha receptors or biologic agents that suppress or inhibit TNFalpha production may also show therapeutic promise.

Therapeutic and prophylactic thalidomide in TNBS-induced colitis: Synergistic effects on TNF-α, IL-12 and VEGF production

AIM: To evaluated the therapeutic and prophylactic effect of thalidomide on 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Thalidomide has been reported to downregulate the expression of tumor necrosis factor α (TNF-α), IL-12, and vascular endothelial growth factor (VEGF), hallmarks of intestinal inflammation in Crohn’s disease (CD).

METHODS: Male Wistar rats were divided in five groups of ten animals each. Four groups received a rectal infusion of TNBS in ethanol. The first group was sacrificed 7 d after colitis induction. The second and third groups received either thalidomide or placebo by gavage and were sacrificed at 14 d. The fourth group received thalidomide 6 h before TNBS administration, and was sacrificed 7 d after induction. The fifth group acted as the control group and colitis was not induced. Histological inflammatory scores of the colon were performed and lamina propria CD4+ T cells, macrophages, and VEGF+ cells were detected by immunohistochemistry. TNF-α and IL-12 were quantified in the supernatant of organ cultures by ELISA.

RESULTS: Significant reduction in the inflammatory score and in the percentage of VEGF+ cells was observed in the group treated with thalidomide compared with animals not treated with thalidomide. Both TNF-α and IL-12 levels were significantly reduced among TNBS induced colitis animals treated with thalidomide compared with animals that did not receive thalidomide. TNF-α levels were also significantly reduced among the animals receiving thalidomide prophylaxis compared with untreated animals with TNBS-induced colitis. Intestinal levels of TNF-α and IL-12 were significantly correlated with the inflammatory score and the number of VEGF+ cells.

CONCLUSION: Thalidomide significantly attenuates TNBS-induced colitis by inhibiting the intestinal production of TNF-α, IL-12, and VEGF. This effect may support the use of thalidomide as an alternate approach in selected patients with CD.

Off-label uses of biologics in dermatology: Rituximab, omalizumab, infliximab, etanercept, adalimumab, efalizumab, and alefacept (Part 2 of 2)

Recently, dermatologists have witnessed a revolution in our therapeutic armamentarium with the development of several novel biologic immunomodulators. Although psoriasis remains the only condition in dermatology for which the use of biologic immunomodulators has been approved by the Food and Drug Administration, these drugs have the potential to significantly impact the treatment of several inflammatory conditions in dermatology. This article includes a review of the mechanism of action, dosing, and side-effect profile, as well as a review of the current literature on off-label uses of the CD20-positive B-cell antagonist rituximab, the IgE antagonist omalizumab, the tumor necrosis factor-alpha antagonists infliximab, etanercept, and adalimumab, and the T-cell response modifiers efalizumab and alefacept.

Apoptosis as a therapeutic tool in IBD?

Defective apoptosis of mucosal cell populations seems to be a relevant pathogenetic mechanism in inflammatory bowel disease (IBD). It has been suggested that the induction of apoptosis in various effector cells may be a relevant therapeutic mechanism in IBD. Indeed, it was shown that different drugs used for treatment of IBD have the capacity to induce apoptosis in T cells or monocytes in vitro and in vivo. However, it remains unclear whether these observations are related to clinical efficacy of these agents. TNF-alpha is one of the most relevant proinflammatory mediators in IBD and anti-TNF treatment has been shown to be of particular benefit for patients with IBD. It could subsequently be shown that various anti-TNF-alpha agents, such as infliximab and adalimumab, can induce apoptosis in activated monocytes and lymphocytes in vitro and in vivo. This mechanism requires reverse signaling via transmembranous TNF, thereby eliciting a signal transduction cascade that results in programmed cell death. Although other mechanisms might also contribute to the clinical effect of anti-TNF-alpha, current data suggest that apoptosis is a relevant mechanism that is associated with clinical efficacy of anti-TNF agents. Induction of apoptosis in activated monocytes or T cells may be regarded as therapeutic tool not only for anti-TNF agents, but also for other drugs used in IBD. Future strategies should focus on identification of mechanisms that prevent apoptosis in the mucosa of patients with IBD and in targeting apoptotic pathways as a therapeutic strategy in IBD.

Pentoxifylline : l'anti-TNF du pauvre ?

PURPOSE

Pentoxifylline (PTX) is a phosphodiesterase inhibitor drug used to improve peripheral vascular disease. In vitro studies demonstrated that PTX has anti-TNFalpha properties. We did a selective review of clinical trials which used PTX in patients with inflammatory rheumatic and non-rheumatic diseases.

CURRENT KNOWLEDGE AND KEY POINTS

Most of the identified clinical trials were uncontrolled and involved a low number of patients. Use of PTX in systemic lupus erythematous, Behçet's disease and sarcoidosis yielded significant preliminary results. Moreover, PTX markedly reduced proteinuria in several glomerulonephritis (lupus nephritis, membranous nephropathy, diabetic nephropathy).

FUTURE PROSPECTS AND PROJECTS

Further randomized and controlled clinical trials are required to examine whether PTX can improve outcome in patients with inflammatory diseases. Meanwhile, PTX should not be used for the treatment of these diseases.

Evolving knowledge and therapy of inflammatory bowel disease

With recent advances in the understanding of its pathophysiology, inflammatory bowel disease has become a very active area for the development of novel therapeutic agents. New targets for biologics include cytokines involved in T-cell activation, with antibodies directed against IL-12 and interferon-gamma. Selective adhesion molecule blockade has produced promising, though mixed, results. Recombinant human granulocyte-macrophage colony-stimulating factor might be effective in active Crohn's disease, presumably through stimulation of intestinal innate immune responses. With increasing evidence for a crucial role for luminal flora in maintaining the health of the bowel, strategies to manipulate intestinal bacteria using probiotics and prebiotics are being actively investigated as well.

Inhibition of TNF-alpha improves indomethacin-induced enteropathy in rats by modulating iNOS expression

TNF-alpha, including other proinflammatory cytokines alone or in combination, induces iNOS expression and upregulates inflammatory responses. We evaluated the relationship between TNF-alpha and iNOS expression in indomethacin-induced jejunoileitis in male Sprague-Dawley rats. Rats were fed a daily dose of a phosphodiesterase inhibitor-either theophylline or pentoxifylline-for 2 days. Jejunoileitis was induced with two subcutaneous injections of indomethacin (7.5 mg/kg) 24 hr apart and theophylline or pentoxifylline continued for 12 hr or 4 days. Other rats received a single intraperitoneal injection of anti-TNF-alpha monoclonal antibody (TNF-Ab) 30-min before indomethacin. At 4 days TNF-Ab, theophylline, or pentoxifylline treatment significantly decreased indomethacin-induced ulceration, myeloperoxidase activity, and disease activity index. Although indomethacin significantly increased serum TNF-alpha and nitrate/nitrite levels over the control value as early as 12 hr, iNOS expression was detected only after 4 days. Serum IL-1beta level did not change at 12 hr but increased fourfold at 4 days. Treatment with TNF-Ab, theophylline, or pentoxifylline significantly reduced serum/tissue TNF-alpha, IL-1beta, nitrate/nitrite, and iNOS expression. The downregulation of nitrate/nitrite by these inhibitors suggests that TNF-alpha modulates iNOS expression.

Novel targets for the treatment of endometriosis

Endometriosis is an enigmatic, debilitating disease that affects up to 15% of all women of reproductive age. It is characterised by pelvic pain and infertility. Current treatment regimens control the disease by inducing a hypoestrogenic state. Although the absence of circulating oestrogen levels leads to a regression of the disease, this hypoestrogenism also induces many unpleasant side effects. As such, these and other shortcomings of current drug therapies emphasise their limitations and the necessity for the development of novel endometriosis treatments. In this review, current therapies for medical management of endometriosis are discussed, as are their shortcomings. Potential target areas that may be attractive alternatives to current therapies are also reviewed. Emphasis is placed upon the emerging research using TNF inhibitors, their potential benefits over current treatment regimens and the development of future potential therapeutic targets.

Crohn's disease: future anti-tumor necrosis factor therapies beyond infliximab

The dramatic benefit experienced by many Crohn's disease patients treated with the anti-tumor necrosis factor-alpha (TNF-alpha) antibody infliximab underscores the centrality of this cytokine in the pathogenesis of Crohn's disease and the potential use of the therapeutic strategy of blocking TNF-alpha in this disease. In the hopes of emulating and improving on the success of infliximab, numerous strategies are being devised and studied to inhibit the actions of TNF-alpha. This article focuses on those agents, other than infliximab, which target TNF-alpha to treat inflammatory bowel disease as their central mechanism of action.

Defective mucosal T cell death is sustainably reverted by infliximab in a caspase dependent pathway in Crohn's disease

BACKGROUND AND AIMS

To verify whether targeting defective mucosal T cell death underlies the sustained therapeutic benefit of infliximab in Crohn's disease, we explored its in vivo proapoptotic effect after 10 weeks of treatment, and its in vitro killing activity on lamina propria T cells (LPT) and peripheral blood T cells (PBT), both isolated from Crohn's disease patients.

METHODS

Endoscopic intestinal biopsies were collected from 10 Crohn's disease patients (six steroid refractory and four fistulising) before and after three consecutive infusions of infliximab, administered at week 0, 2, and 6 in a single intravenous dose (5 mg/kg), and from 10 subjects who proved to have functional diarrhoea. Apoptosis was determined in vivo by TUNEL assay, and in vitro by fluorescein isothiocyanate-annexin V/propidium iodide staining on LPT and PBT from Crohn's disease patients cultured with infliximab. The effect of the broad caspase inhibitor Z-VAD-FMK and the neutralising anti-Fas antibody ZB4 was tested in vitro on LPT and PBT treated with infliximab. Caspase-3 activity was determined by immunoblotting.

RESULTS

In Crohn's disease patients, infliximab treatment induced a sustained LPT apoptosis, still evident four weeks after the last infusion. In vitro infliximab induced death of LPT from Crohn's disease patients occurred via apoptosis rather than necrosis. LPT showed a higher susceptibility to infliximab induced apoptosis than PBT in Crohn's disease patients. The signalling pathway underlying the restoration of infliximab induced LPT apoptosis occurred via the caspase pathway but not Fas-Fas ligand interaction in Crohn's disease.

CONCLUSIONS

These findings demonstrate that apoptosis is the major mechanism by which infliximab exerts its killing activity on LPT in Crohn's disease. The sustained LPT proapoptotic action of infliximab, which extends far beyond its circulating half life, may be responsible for the sustained remission induced in Crohn's disease patients by infliximab retreatment.

Evaluation of new therapies for inflammatory bowel disease

The pathophysiology of inflammatory bowel disease (IBD) is gradually being unravelled and new therapies are being developed to target the disturbed biological processes. This article outlines the clinical features of IBD, its current therapy and pathogenesis. The difficulties for clinical pharmacologists and gastroenterologists associated with designing, executing and interpreting clinical trials in IBD are then discussed. The final section reviews methods that can used to demonstrate the pharmacological actions of new treatments in patients with IBD. It is emphasized that proof of the therapeutic efficacy of a novel agent with a specific mechanism of action yields not only clinical benefit to patients with IBD, but also indicates the importance of the targeted biochemical pathway in the pathogenesis of the disease.

RDP58, a Novel Immunomodulatory Peptide with Anti-Inflammatory Effects. A Pharmacological Study in Trinitrobenzene Sulphonic Acid Colitis and Crohn Disease

BACKGROUND

Tumour necrosis factor (TNF) plays a key role in the pathogenesis of Crohn disease (CD). RDP58 is a novel anti-inflammatory decapeptide which was developed using a novel rational design strategy. Recently, RDP58 has proved to be a potent inhibitor of TNF production at a post-transcriptional step. The aims of this study were to investigate the anti-inflammatory properties of RDP58 ex vivo in human CD and in vivo in an experimental model colitis.

METHODS

Biopsies and lamina propria mononuclear cells from inflamed colonic mucosa of 18 CD patients were cultured for 24 h in the presence or absence of RDP58. TNF was quantified in a bioassay; interferon (IFN)-γ and interleukin (IL)-1β levels were measured by enzyme-linked immunosorbent assays. Colitis was induced by intra-rectal administration of 2, 4, 6 trinitrobenzene sulphonic acid (TNBS) in rats. Inflammation was assessed following 7 days of oral therapy with RDP58 or vehicle alone.

RESULTS

RDP58 led to decreased TNF and IFN-γ (but not IL-1β) production by biopsies and lamina propria mononuclear cells from CD patients. In rats with TNBS-induced colitis, oral RDP58 therapy reduced weight loss and diarrhoea and improved macroscopic and histological inflammation scores.

CONCLUSIONS

Our results suggest that RDP58 may be an effective therapy for CD with the clinical advantage of an oral administration.

Small therapeutic molecules for the treatment of inflammatory bowel disease

New therapies for inflammatory bowel disease are needed, because standard therapies fail to induce remission in about 30% of patients, and because of the relative inefficacy of current maintenance therapies. This review summarises the current status of the development of small therapeutic molecules for inflammatory bowel disease.

Thalidomide reduces tumour necrosis factor alpha and interleukin 12 production in patients with chronic active Crohn's disease

BACKGROUND

Thalidomide improves clinical symptoms in patients with therapy refractory Crohn's disease, as shown in two recent studies. The mechanism of this effect however is still unknown. Suppression of tumour necrosis factor alpha (TNF-alpha) by thalidomide has been suggested as a possible mechanism. However, effects on other cytokines have not been adequately investigated.

AIM

The aim of our study was to investigate the effects of thalidomide on cytokine production in patients with inflammatory bowel disease (IBD).

METHODS

Ten patients with therapy refractory IBD (nine Crohn's disease, one ulcerative colitis) received thalidomide 300 mg daily in a 12 week open label study. Production of TNF-alpha, interleukin (IL)-1 beta, IL-6, and IL-12 was investigated in short term cultures of stimulated colonic lamina propria mononuclear cells (LPMC) and peripheral blood monocytes (PBMC) before and after 12 weeks of treatment. LPMC were also cultured with graded doses of thalidomide.

RESULTS

Three patients discontinued treatment because of sedative side effects. In the other patients, disease activity decreased significantly, with four patients achieving remission. Production of TNF-alpha and IL-12 decreased during treatment with thalidomide: LPMC (TNF-alpha: 42.3 (8.3) pg/ml v 16.4 (6.3); IL-12: 9.7 (3.3) v 5.0 (2.5); p<0.04) and PBMC (TNF-alpha: 62.8 (14.6) v 22.5 (9.2); p<0.02). Production of IL-1 beta and IL-6 did not change significantly. Culturing of LPMC with thalidomide showed a dose dependent decrease in TNF-alpha and IL-12 production.

CONCLUSION

The clinical effects of thalidomide in Crohn's disease may be mediated by reduction of both TNF-alpha and IL-12.

Anti-TNF-alpha properties of new 9-benzyladenine derivatives with selective phosphodiesterase-4- inhibiting properties

In inflammatory cells, intracellular cAMP concentration is regulated by cyclic nucleotide phosphodiesterases 4. Therefore, PDE4 inhibition appears as a rational goal for treating acute or chronic inflammatory diseases. Selective PDE4 inhibitors have been developed, but due to unwanted side effects, search for new selective PDE4-inhibitors had to be pursued. Recently, Boichot et al. (J. Pharmacol. Exp. Ther. (2000) 292, 647-653) showed that 9-benzyladenine derivatives are selective PDE4 inhibitors. In vivo data in animals suggested that they may induce fewer side effects (emesis). We examined the effects of new 9-benzyladenines on TNF-alpha, interleukin (IL)-1beta, IL-6 and IL-8 production by lipopolysaccharide-activated peripheral blood mononuclear cells, and compared them to other PDEs inhibitors. Selected potent 9-benzyladenines, strongly inhibited TNF-alpha production. Interleukin-1beta, IL-6, and IL-8 production was not significantly affected. Our results suggest that some of these new adenines (i.e., NCS 675 and NCS 700), may be potential therapeutic candidates for the treatment of inflammatory diseases.

Pentoxifylline influences the autocrine function of organ cultured donor corneas and enhances endothelial cell survival

BACKGROUND/AIMS

Scientific interest in pentoxifylline has been reawakened owing to the recognised effects of this drug on immune functions, particularly its influence on cytokine production. In a previous study, the authors demonstrated that spiking of organ culture media with endotoxin elicited a marked enhancement in the release of IL-6 and IL-8 from corneal tissue and that these events coincided with degenerative changes in endothelial cells and a higher incidence of actual loss among this population. Since traces of donor derived endotoxin can be detected in up to 50% of corneal organ cultures, this substance may have a direct influence on graft viability or trigger inflammatory responses in the host. They, therefore, wished to ascertain whether supplementation of media with pentoxifylline improved endothelial cell survival in organ cultured donor corneas.

METHODS

12 fellow pairs of donor corneas were cultured for 20 days, with a change of medium on day 10: One of each pair was incubated in the absence, and the other in the presence, of pentoxifylline (25 microg/ml). Samples of medium were withdrawn at regular intervals during the course of incubation and screened for cytokines IL-6, IL-8, and prostaglandin E2 by ELISA. Endothelial cell morphology and numerical density were assessed on days 0, 10 and 20.

RESULTS

Addition of pentoxifylline to organ culture media led to a significant improvement in endothelial cell survival. This drug also elicited a significant increase in the level of IL-6 and marginally suppressed that of IL-8 during the initial 10 day phase of incubation. During the second 10-20 day phase, the level of both IL-6 and IL-8 decreased significantly in the presence of pentoxifylline, the relation between these two cytokines being the inverse of that observed in the absence of the drug. No significant changes in the level of prostaglandin E2 were apparent.

CONCLUSION

The addition of pentoxifylline to organ culture media leads, ultimately, to a suppression of IL-6 and IL-8 secretion by corneal tissue. The potentially damaging effects of these cytokines are thereby quelled, as evidenced by the improvement in endothelial cell survival.

Potent inhibition of cytokine production from intestinal lamina propria T cells by phosphodiesterase-4 inhibitory thalidomide analogues

In Crohn's disease, intestinal lamina propria (LP) T cells overproduce TNF-alpha and IFN-gamma, and clinical and animal studies indicate that this is pathogenic. Thalidomide influences cytokine production by leukocytes, inhibiting macrophage TNF-alpha, and is beneficial in treating Crohn's disease. Chemical analogues have been synthesized that may lack teratogenic and other side effects of thalidomide. We tested three analogues [selective cytokine inhibitory drugs (SelCIDs) A, B, and C, all potent PDE4 inhibitors] for effect on TNF-alpha, IFN-gamma, and IL-10 production by and on proliferation of intestinal LP mononuclear cells after T-cell stimulation and results were compared with those for peripheral blood leukocytes (PBL). While thalidomide itself had little effect, the SelCIDs were potent inhibitors, with relative inhibitory potencies: A> or =B>>C. The LP T cells were less sensitive to inhibition by the SelCIDs than were PBL. Since highly pre-activated PBL were even less sensitive, activation state alone can account for the responsiveness of intestinal LP T cells. Thalidomide analogues could play a role in treating Crohn's disease and other inflammatory disorders.

Combination therapy including pentoxifylline for entero-Behçet's disease

Behçet's disease is a chronic relapsing vasculitis characterized by recurrent aphthous oral and genital ulcerations with uveitis. Multiple organs can be involved. Entero-Behçet's disease is often uncontrollable, relapsing, and can cause acute intestinal bleeding or perforation. We utilized a combination therapy including 600 mg of pentoxifylline per day, in two doses, to treat three female patients and observed the subsequent changes in clinical symptoms, serum C reactive protein levels, and endoscopic findings. In all three patients, clinical symptoms as well as serum C reactive protein levels improved immediately. Endoscopically, lower intestinal lesions were significantly reduced or healed in all of them. Combination therapy including pentoxifylline appears to be clinically effective in the patients with entero-Behçet's disease.

Treating endometriosis as an autoimmune disease

OBJECTIVE

To review the literature on the role of autoimmunity in the etiology of endometriosis, compare the similarities in the pathophysiologies between endometriosis and autoimmune diseases, and discuss the use of immunomodulators currently used to treat autoimmune diseases as potential therapies for endometriosis.

DESIGN

The literature on endometriosis and other autoimmune diseases was reviewed, and summary data are presented.

RESULTS

Endometriosis shares many similarities with autoimmune diseases such as rheumatoid arthritis, Crohn's disease, and psoriasis. These similarities include elevated levels of cytokines, decreased cell apoptosis, and T- and B-cell abnormalities. Because the use of immunomodulators and inflammatory modulators has proven to be an effective means of medical management for these autoimmune diseases, similar therapies may prove useful in treating endometriosis.

CONCLUSION(S)

Although substantial evidence indicates that endometriosis at least shares many similarities with autoimmune diseases, endometriosis is primarily treated by using compounds that induce a hypoestrogenic environment. A review of the literature combined with the shortcomings of current means of medical management for endometriosis support the postulate that treatment of endometriosis with immunomodulators and inflammatory modulators is warranted.

Novel therapies in the treatment of ulcerative colitis

Ulcerative colitis is a chronic inflammatory disease of unknown cause. Its course is one of relapse and remission and requires therapy for both the induction and maintenance of remission. The progress in the fields of genetics and immunology has afforded important advances in our understanding of the inflammatory process. Traditional therapy with non-specific anti-inflammatories for ulcerative colitis remains our gold standard as newer targeted therapies have failed to provide any improved efficacy. This review examines the most recent compounds in development for the treatment of ulcerative colitis, including data from early clinical trials and the potential clinical impact of future entities.

Splenectomy and sepsis: the role of the spleen in the immune-mediated bacterial clearance

Over the past few years, many observations of overwhelming post splenectomy bacterial infections have been reported. Streptococcus pneumoniae is the aetiologic agent in about 80% of cases, but also gram-negative bacteria are involved in the development of fatal infections in splenectomized patients. Functionally, the spleen plays a fundamental role in bacterial clearance either by antibody response or macrophage bactericidal capacity. At the same time, there is evidence that the spleen also contributes to bacterial endotoxin detoxification. Finally, the mechanisms responsible for gram-positive and gram-negative sepsis in the splenectomized host and possible therapeutical approaches able to neutralize bacterial products endowed with noxious effects are discussed.

Immunotherapeutic approaches to inflammatory bowel diseases

For a long time corticosteroids, aminosalicylic acid preparations and antibiotics have represented the principal approaches in evidence-based drug therapy for chronic inflammatory bowel diseases (IBD), e.g., Crohn's disease (CD) and ulcerative colitis (UC), and are able to suppress disease activity in most cases. However, there are cases that do not respond to conventional drug therapy or remain dependent on high doses of steroids associated with severe side effects in the long run. It is generally accepted now that IBD has an immunological basis and results from a hyperresponsive state of the intestinal immune system. Although the primary etiological defect respectively immunogenic agent still remains to be identified, substantial progress has been made in our understanding to regulatory mechanisms of the intestinal immune system and their alterations in IBD at the molecular level. Due to the concurrent advent of biotechnological processes it has been possible to utilise these insights for the development of novel immunomodulatory therapeutic strategies ranging from recombinant cytokines and blocking antibodies to oligonucleotide antisense strategies and gene therapeutic approaches. This review will present the current status of the development of these novel immunomodulatory therapeutic strategies in IBD and the status of their use in clinical practice. For a better understanding, it will be necessary to address the recent advances in the elucidation of pathogenetic mechanisms of IBD from studies in human specimen and experimental colitis models that have provided the basis for these novel therapeutic approaches.

Interleukin 10 in Helicobacter pylori associated gastritis: immunohistochemical localisation and in vitro effects on cytokine secretion

BACKGROUND/AIMS

Interleukin 10 (IL-10) is a counter-inflammatory peptide implicated in the downregulation of human intestinal immune responses. Enhanced secretion of IL-10 has been documented in gastric biopsy organ culture in Helicobacter pylori infection. This study aimed to define the cellular origins of IL-10 in H pylori associated gastritis, and to determine the effects of endogenous IL-10 on proinflammatory cytokine secretion in vitro.

METHODS

Endoscopic biopsies were obtained from the gastric antrum at endoscopy from patients with dyspepsia. Two pairs of antral biopsies were cultured in vitro for 24 hours, one pair in the presence of neutralising anti-IL-10 monoclonal antibody, the other pair as controls. The cytokine content of culture supernatants (tumour necrosis factor alpha (TNF-alpha), IL-6, and IL-8) was determined by enzyme linked immunosorbent assay and corrected for biopsy weight. Helicobacter pylori status was established by histology and biopsy urease test, and histopathology graded by the Sydney system. In a subgroup of patients, western blotting was used to establish CagA serological status. Immunohistochemistry for IL-10 was performed on formalin fixed tissues using a combination of microwave antigen retrieval and the indirect avidin-biotin technique. Immunoreactivity was scored semiquantitatively.

RESULTS

In vitro culture was performed in 41 patients: 31 with H pylori positive chronic gastritis and 10 H pylori negative. In vitro secretion of TNF-alpha, IL-6, and IL-8 for "control" biopsies was significantly higher in H pylori positive versus negative samples, with values of TNF-alpha and IL-6 correlating with the degree of active and chronic inflammation and being higher in CagA seropositive cases. No evidence for enhanced cytokine secretion was seen in biopsies cocultured in the presence of anti-IL-10 monoclonal antibody. Immunohistochemistry was performed in 29 patients, of whom 13 were H pylori positive. IL-10 immunoreactivity was observed in the surface epithelium in all H pylori positive cases and in 13 of 16 negative cases, especially in areas of surface epithelial degeneration. Lamina propria mononuclear cells (LPMNCs) were positively stained in all H pylori positive cases and in 12 of 16 negative cases, with a significantly greater proportion of positive LPMNCs in the positive group.

CONCLUSIONS

This study localised IL-10 protein to the gastric epithelium and LPMNCs. In vitro proinflammatory cytokine secretion was increased in H pylori infection (especially CagA positive infection), but blocking endogenous IL-10 secretion did not significantly increase cytokine secretion. IL-10 is implicated in H pylori infection and might "damp down" local inflammation. The role of gastric IL-10 secretion in determining the clinicopathological outcome of infection merits further study.

The effect of inflammation severity and of treatment on the production and release of TNFalpha by colonic explants in inflammatory bowel disease

BACKGROUND

Despite its pivotal role in mucosal inflammation, data on TNFalpha levels in inflammatory bowel diseases have been contradictory.

AIM

To examine TNFalpha production in relation to the type and severity of inflammation and therapy, using colonic explant cultures.

MATERIALS AND METHODS

Rectal mucosal biopsies from 271 paediatric patients (178 inflammatory bowel disease, 27 inflammatory controls, 66 normal) were cultured for 4 or 18 h. Basal TNFalpha tissue content and release into the medium were measured by ELISA and compared to histological severity and clinical parameters.

RESULTS

TNFalpha release as well as tissue-associated TNFalpha levels were significantly increased in rectal biopsies from involved inflammatory bowel disease tissue. The amount of TNFalpha correlated with inflammation severity scores. TNFalpha levels were higher at 18 compared to 4 h in all groups, whether inflamed or not. TNFalpha released from rectal biopsies was lower among treated patients at 18 h. The presence of proximal colonic involvement was associated with higher TNFalpha release by uninvolved Crohn's disease rectal biopsies compared to patients with ileitis alone.

CONCLUSIONS

TNFalpha production and release is increased in involved rectal explants from inflammatory bowel disease. Anti-inflammatory treatment diminishes this response.

Kimura's disease with oral ulcers: response to pentoxifylline

We describe a man with Kimura's disease whose presentation included lymphadenopathy and cutaneous nodules, but was most distinctive for painful oral ulcerations. His lesions showed an initially moderate, but ultimately minimal response to monthly triamcinolone injections. With oral pentoxyifylline, he showed resolution of all of his lesions for 14 months. On cessation of his treatment, his disease flared for 3 months. When pentoxyifylline was restarted, his lesions regressed again within 4 weeks. We review the literature on Kimura's disease.

New immunologic treatments for inflammatory bowel disease

After many years with little progress in new treatments for patients with inflammatory bowel disease, there is now rapid expansion of a new class of immunologic agents. These agents are designed to disrupt proinflammatory pathways at specific sites. Monoclonal antibodies to tumor necrosis factor-alpha (TNF-alpha) are already transforming the lives of some patients with previously intractable Crohn disease, and further TNF-alpha directed therapies are being developed. Clinical trials are now underway on agents that inhibit adhesion molecules and antiinflammatory cytokines, while attempts are being made to actively immunize against TNF-alpha. Promising data continue to be reported, although long-term safety data are still mostly unavailable. Although these agents are proving to be very effective in the treatment of patients with Crohn disease, their use should continue to be restricted while indications and dose regimens are defined.

[Value of anti-TNF-alpha molecules in inflammatory and infectious diseases]

INTRODUCTION

The pathophysiological interest of tumor necrosis factor-alpha (TNF-alpha) has been recently reported in inflammatory and infectious diseases. Thus, TNF-alpha blockade has become a new field of therapeutical research.

CURRENT KNOWLEDGE AND KEY POINTS

Several biological agents specifically directed against TNF-alpha are available: anti-TNF-alpha monoclonal antibodies on the one hand--either mainly murine sequence (cA2), partially humanized (CDP 571) or fully human (D2E7)--and TNF-alpha soluble receptors on the other hand (lenercept or etanercept). The first clinical studies reveal interesting results. In rheumatoid arthritis (cA2, etanercept), these molecules may be used either alone or in synergistic combination with methotrexate. They produce a significant response compared to placebo or methotrexate alone, without loss of efficacy in medium-term treatment. In Crohn's disease (cA2 CDP571), they reduce significantly the activity of the disease, compared to placebo, and cA2 makes it possible to accelerate closure of the fistulas. The studies of severe sepsis did not reveal a significant efficacy, however, and only one study has been published on malignant disease, with a possible interesting effect. Even if these medications are usually well tolerated, the frequency of infections is slightly increased. The development of anti-DNA antibodies has also been reported, but drug-induced lupus is highly unusual.

FUTURE PROSPECTS AND PROJECTS

Further studies will define the place of anti-TNF-alpha biological agents among the other available treatments of rheumatoid arthritis and Crohn's disease. Because of their high cost, these drugs will probably be limited to patients with active inflammatory disease despite more conventional treatments.

A pilot study of pentoxifylline for the treatment of primary sclerosing cholangitis

OBJECTIVE

There is no effective therapy for patients with primary sclerosing cholangitis (PSC). Rats with experimental small bowel bacterial overgrowth develop hepatobiliary injury similar to PSC. The hepatobiliary injury results from peptidoglycan-polysaccharide-mediated activation of Kupffer cells, release of cytokines such as tumor necrosis factor (TNF-alpha), and is prevented by pentoxifylline. Our aims were to assess the safety and effects of pentoxifylline on symptoms and biochemical liver tests in patients with PSC.

METHODS

A total of 20 patients with clinical, cholangiographic, and histological features of PSC of varying severity were treated with pentoxifylline sustained release (SR) tablets (400 mg q.i.d.) for < or = 1 yr. Serum alkaline phosphatase, aspartate aminotransferase, and bilirubin were monitored every 3 months for 1 year; serum TNF-alpha and TNF receptor subtypes I and II were assessed at baseline and 1 year.

RESULTS

Of 20 patients, 16 tolerated pentoxifylline and completed the study. Two patients were withdrawn because of severe nausea, and two patients were noncompliant with medication and withdrew. Pentoxifylline did not significantly alter symptoms of fatigue or pruritus, serum liver tests, serum TNF-alpha or TNF receptor levels.

CONCLUSIONS

In the current regimen, pentoxifylline alone does not significantly improve symptoms or liver tests in patients with PSC.

Phosphodiesterase 4 inhibitors, structurally unrelated to rolipram, as promising agents for the treatment of asthma and other pathologies

An increase of cyclic adenosine and guanosine monophosphate (cAMP and cGMP) level can be achieved by inhibition of phosphodiesterases (PDEs), which are the enzymes responsible for the conversion of these second messengers into the corresponding 5-monophosphate inactive counterparts. The high heterogeneity in PDE families and in their tissue distribution, as well as their different functional role, make these enzymes very attractive targets for medicinal chemists. The PDE 4 family is particularly abundant in immunocompetent cells, where an increase of cAMP leads to the inhibition of the synthesis and release of pro-inflammatory mediators, cytokines and active oxygen species. Moreover PDE 4 inhibitors are able to reduce bronchial smooth muscle tone in vitro and show bronchodilatory effects in vivo. Thus, the current therapy for asthma, which is based on a combination of beta(2) agonists and corticosteroids, could be replaced by treatment with PDE 4 inhibitors. This review mainly covers PDE 4 inhibitors structurally related to xanthines and Nitraquazone, which appear to be very attractive models for the synthesis of novel PDE 4 inhibitors potentially useful for the treatment of asthma, chronic pulmonary obstructive disease and some autoimmune diseases. These compounds could be devoid of the central side-effects (nausea, vomiting, headache) of the archetypal Rolipram, which hampered its development as a drug. The review also highlights the novel structural classes of PDE 4 inhibitors recently reported in the literature.

Cytokine-induced intestinal epithelial hyperpermeability: role of nitric oxide

OBJECTIVE

Incubation of enterocytic monolayers with interferon (IFN)-gamma increases nitric oxide (NO) production and permeability, but NO synthesis inhibitors ameliorate the development of IFN-gamma-induced hyperpermeability. Induction of inducible nitric oxide synthase (iNOS), an isoform of the enzyme responsible for NO biosynthesis, is often enhanced by the synergistic effects of multiple cytokines. Moreover, many of the cytopathic effects of NO are mediated by peroxynitrite, which is produced by the reaction of NO with superoxide radical anion. In the present study, we sought to determine whether combinations of several proinflammatory cytokines, including IFN-gamma, interleukin-1beta, and tumor necrosis factor-alpha, have synergistic effects on the induction of iNOS expression and/or hyperpermeability to hydrophilic solutes in cultured enterocytic monolayers. We also assessed the effects of aminoguanidine (a relatively selective iNOS inhibitor), L-N(G)-monomethyl arginine (an isoform-nonselective NO synthase inhibitor), and Tiron (a superoxide radical anion scavenger) on the development of cytokine-induced hyperpermeability.

DESIGN

Caco-2 monolayers were incubated under control conditions or with IFN-gamma, interleukin-1beta, or tumor necrosis factor-alpha alone, pairwise combinations of these cytokines, or all three cytokines together (cytomix; CM). iNOS messenger RNA (mRNA) expression was assessed using Northern blot analysis. The permeability of Caco-2 monolayers growing on permeable supports in bicameral chambers was assessed by measuring the apical-to-basolateral flux of fluorescein disulfonic acid. The concentration of nitrate plus nitrite in culture supernatants, an indirect measure of NO production, was determined using the Griess reaction.

RESULTS

After 24 hrs of incubation, up-regulation of iNOS mRNA expression was evident only in cells exposed to IFN-gamma-containing formulations. Expression of iNOS mRNA was far greater in cells incubated with CM than in cells treated with IFN-gamma alone or either of the two-component IFN-gamma-containing cytokine combinations. Compared with IFN-gamma, CM resulted in a higher rate of NO production over 48 hrs of incubation. The permeability of Caco-2 monolayers increased by approximately six-fold and approximately 20-fold after incubation for 48 hrs with IFN-gamma alone and CM, respectively. The increase in permeability induced by incubation with CM was significantly ameliorated by the addition of aminoguanidine, L-N(G)-monomethyl arginine, or Tiron.

CONCLUSIONS

IFN-gamma-containing combinations of cytokines are potent inducers of iNOS in cultured enterocytic monolayers. Peroxynitrite may be an important mediator of cytokine-induced gut epithelial hyperpermeability.

Tumour necrosis factor-alpha (TNF-alpha) transcription and translation in the CD4+ T cell-transplanted scid mouse model of colitis

The adoptive transfer of activated CD4+ alpha/beta T cell blasts from the spleens of immunocompetent C.B-17+/+ or BALB/cdm2 mice into C.B-17scid/scid (scid) mice induces a colitis in the scid recipient within 8 weeks, which progresses to severe disease within 16 weeks. T cells isolated from recipient colon show a Th1 cytokine phenotype. We have examined the relationship between the phenotype of the cellular infiltrate and the transcription and translation of the proinflammatory cytokine TNF-alpha. The techniques of double indirect immunohistology and in situ hybridization using digoxigenin-labelled riboprobes were used. The prominent myeloid cell infiltrate in diseased tissues comprised F4/80+, Mac-l+ macrophages, neutrophils, dendritic cells and activated macrophages. TNF-alpha transcription and translation were associated with activated macrophages in the lamina propria. Activated macrophages transcribing and translating TNF-alpha were clustered in areas of tissue destruction. Crypt epithelium of inflamed tissues transcribed TNF-alpha at a very early stage of the disease process, but translation of TNF-alpha protein could only be found in advanced epithelial dysplasia. This indicates differential post-transcriptional control of TNF-alpha in activated macrophages and the epithelium.