RDP58 is a novel and potentially effective oral therapy for ulcerative colitis

Oral administration of RDP58 ameliorated DSS-induced colitis in intestinal microbiota dependent manner

BACKGROUND

Although the pathogenesis of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), has not been fully elucidated, accumulating researches suggest that intestinal microbiota imbalance contributes to the development of IBD in patients and animal models. RDP58, a peptide-based computer-assisted rational design, has been demonstrated to be effective in protecting against a wide range of autoimmune and inflammatory diseases. However, the underlying mechanism by which RDP58 protects against IBD mediated by intestinal microbiota has yet to be elucidated.

METHODS

The colitis model was induced by continuously administering 2.5 % (wt/vol) dextran sodium sulfate (DSS) solution for 7 days. The manifestations of colon inflammation were assessed via daily weight changes, colon length, tumor necrosis factor-alpha (TNF-α) level, disease activity index (DAI) score, pathology score, and intestinal barrier permeability. Intestinal microbiota analysis was carried out by 16S-rRNA sequencing. Colonic short chain fatty acids (SCFAs) and regulatory T cells (Tregs) were also detected. To further confirm the protective effect of RDP58 on intestinal microbiota, broad-spectrum antibiotic cocktail (ABX) treatment and fecal microbial transplantation (FMT) experiment were performed.

RESULTS

Oral administration of RDP58 ameliorated DSS-induced mice colitis by altering the diversity and composition of intestinal microbiota. Notably, RDP58 significantly upregulated SCFAs-producing microbiota, thereby promoting the generation of Tregs. ABX and FMT were performed to verify the above mechanism.

CONCLUSIONS

RDP58 ameliorated DSS-induced colitis through altering intestinal microbiota and enhancing SCFAs and Tregs production in intestinal microbiota dependent manner, potentially provide a novel therapy for IBD.

Biochemistry, Mechanistic Intricacies, and Therapeutic Potential of Antimicrobial Peptides: An Alternative to Traditional Antibiotics

The emergence of drug-resistant strains of pathogens becomes a major obstacle to treating human diseases. Antibiotics and antivirals are in the application for a long time but now these drugs are not much effective anymore against disease-causing drugresistant microbes and gradually it is becoming a serious complication worldwide. The development of new antibiotics cannot be a stable solution to treat drug-resistant strains due to their evolving nature and escaping antibiotics. At this stage, antimicrobial peptides (AMPs) may provide us with novel therapeutic leads against drug-resistant pathogens. Structurally, antimicrobial peptides are mostly α-helical peptide molecules with amphiphilic properties that carry the positive charge (cationic) and belong to host defense peptides. These positively charged AMPs can interact with negatively charged bacterial cell membranes and may cause the alteration in electrochemical potential on bacterial cell membranes and consequently lead to the death of microbial cells. In the present study, we will elaborate on the implication of AMPs in the treatment of various diseases along with their specific structural and functional properties. This review will provide information which assists in the development of new synthetic peptide analogues to natural AMPs. These analogues will eliminate the limitations of natural AMPs like toxicity and severe hemolytic activities.

Systematic review with meta-analysis: Medical therapies for treatment of ulcerative proctitis

BACKGROUND

Ulcerative proctitis (UP) is a common highly symptomatic form of ulcerative colitis that can be difficult to treat.

AIM

To assess the efficacy of medical treatments for UP.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL on 23 November 2022 for randomised controlled trials (RCTs) of medical therapy for adults with UP. Primary outcomes included induction and maintenance of clinical remission. Pooled risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for each outcome.

RESULTS

We included 53 RCTs (n = 4096) including 46 induction studies (n = 3731) and seven maintenance studies (n = 365). First-line therapies included topical 5-aminosalicylic acid (5-ASA), conventional corticosteroids, budesonide, and oral 5-ASA. Therapy for refractory UP included topical tacrolimus and small molecules. Topical 5-ASA was superior to placebo for induction (RR 2.72, 95% CI 1.94-3.82) and maintenance of remission (RR 2.09, 95% CI 1.26-3.46). Topical corticosteroids were superior to placebo for induction of remission (RR 2.83, 95% CI 1.62-4.92). Topical budesonide was superior to placebo for induction of remission (RR 2.34, 95% CI 1.44-3.81). Combination therapy with topical 5-ASA and topical corticosteroids was superior to topical monotherapy with either agent. Topical tacrolimus was superior to placebo. Etrasimod was superior to placebo for induction (RR 4.71, 95% CI 1.2-18.49) and maintenance of remission (RR 2.08, 95% CI 1.31-3.32).

CONCLUSIONS

Topical 5-ASA and corticosteroids are effective for active UP. Topical 5-ASA may be effective for maintenance of remission. Tacrolimus may be effective for induction of remission. Etrasimod may be effective for induction and for maintenance of remission. Trials should include UP to expand the evidence base for this under-represented population.

Are Antimicrobial Peptides a 21st-Century Solution for Atopic Dermatitis?

Atopic dermatitis (AD) is a chronic inflammatory skin disorder that is the result of various environmental, bacterial and genetic stimuli, which culminate in the disruption of the skin's barrier function. Characterized by highly pruritic skin lesions, xerosis and an array of comorbidities among which skin infections are the most common, this condition results in both a significant loss of quality of life and in the need for life-long treatments (e.g., corticosteroids, monoclonal antibodies and regular antibiotic intake), all of which may have harmful secondary effects. This, in conjunction with AD's rising prevalence, made the development of alternative treatment strategies the focus of both the scientific community and the pharmaceutical industry. Given their potential to both manage the skin microbiome, fight infections and even modulate the local immune response, the use of antimicrobial peptides (AMPs) from more diverse origins has become one of the most promising alternative solutions for AD management, with some being already used with some success towards this end. However, their production and use also exhibit some limitations. The current work seeks to compile the available information and provide a better understanding of the state of the art in the understanding of AMPs' true potential in addressing AD.

Placebo Rates in Randomized Controlled Trials of Proctitis Therapy: A Systematic Review and Meta-Analysis Placebo Response in Proctitis

BACKGROUND AND AIMS

Treatment options for proctitis are limited. To assist trial design for novel therapeutics, we conducted a systematic review and meta-analysis of proctitis randomized controlled trials [RCTs] to quantify placebo rates and identify factors influencing them.

METHODS

We searched MEDLINE, EMBASE and CENTRAL from inception to June 2021. Placebo-controlled trials of pharmacological interventions for proctitis were eligible. Placebo clinical response and remission rates for induction and maintenance trials were extracted and pooled using a random-effects model. Mixed-effects meta-regression was used to evaluate the impact of patient and study-level characteristics.

RESULTS

Twenty RCTs [17 induction and four maintenance phases] were included. The most common intervention was aminosalicylates and most studies investigated topical medications. The pooled placebo clinical response and remission rates for induction trials were 28% (95% confidence interval [CI] 22-35%; n = 17) and 20% [95% CI 12-32%; n = 9], respectively. Pooled placebo endoscopic response and remission rates were 32% [95% CI 26-39%, n = 12] and 18% [95% CI 9-33%, n = 6], respectively. For maintenance trials, the pooled placebo clinical remission rate was 29% [95% CI 16-46%, n = 17]. Trials published after 2005 and trials with a longer duration of follow-up were associated with significantly lower placebo response rates. Nineteen of 20 studies were assessed as having an unclear risk of bias, reflecting the historical nature of trials.

CONCLUSIONS

Placebo response and remission rates in proctitis trials are influenced by trial phase and the endpoint being assessed. These contemporary rates will inform trial design for novel therapeutics for treatment of proctitis, which is a large unmet need.

Antimicrobial Peptides Controlling Resistant Bacteria in Animal Production

In the last few decades, antimicrobial resistance (AMR) has been a worldwide concern. The excessive use of antibiotics affects animal and human health. In the last few years, livestock production has used antibiotics as food supplementation. This massive use can be considered a principal factor in the accelerated development of genetic modifications in bacteria. These modifications are responsible for AMR and can be widespread to pathogenic and commensal bacteria. In addition, these antibiotic residues can be dispersed by water and sewer water systems, the contamination of soil and, water and plants, in addition, can be stocked in tissues such as muscle, milk, eggs, fat, and others. These residues can be spread to humans by the consumption of water or contaminated food. In addition, studies have demonstrated that antimicrobial resistance may be developed by vertical and horizontal gene transfer, producing a risk to public health. Hence, the World Health Organization in 2000 forbid the use of antibiotics for feed supplementation in livestock. In this context, to obtain safe food production, one of the potential substitutes for traditional antibiotics is the use of antimicrobial peptides (AMPs). In general, AMPs present anti-infective activity, and in some cases immune response. A limited number of AMP-based drugs are now available for use in animals and humans. This use is still not widespread due to a few problems like in-vivo effectiveness, stability, and high cost of production. This review will elucidate the different AMPs applications in animal diets, in an effort to generate safe food and control AMR.

Defactinib inhibits PYK2 phosphorylation of IRF5 and reduces intestinal inflammation

Interferon regulating factor 5 (IRF5) is a multifunctional regulator of immune responses, and has a key pathogenic function in gut inflammation, but how IRF5 is modulated is still unclear. Having performed a kinase inhibitor library screening in macrophages, here we identify protein-tyrosine kinase 2-beta (PTK2B/PYK2) as a putative IRF5 kinase. PYK2-deficient macrophages display impaired endogenous IRF5 activation, leading to reduction of inflammatory gene expression. Meanwhile, a PYK2 inhibitor, defactinib, has a similar effect on IRF5 activation in vitro, and induces a transcriptomic signature in macrophages similar to that caused by IRF5 deficiency. Finally, defactinib reduces pro-inflammatory cytokines in human colon biopsies from patients with ulcerative colitis, as well as in a mouse colitis model. Our results thus implicate a function of PYK2 in regulating the inflammatory response in the gut via the IRF5 innate sensing pathway, thereby opening opportunities for related therapeutic interventions for inflammatory bowel diseases and other inflammatory conditions.

Using item response theory (IRT) to improve the efficiency of the Simple Clinical Colitis Activity Index (SCCAI) for patients with ulcerative colitis

BACKGROUND

The SCCAI was designed to facilitate assessment of disease activity in ulcerative colitis (UC). We aimed to interrogate the metric properties of individual items of the SCCAI using item response theory (IRT) analysis, to simplify and improve its performance.

METHODS

The original 9-item SCCAI was collected through TrueColours, a real-time software platform which allows remote entry and monitoring of patients with UC. Data were securely uploaded onto Dementias Platform UK Data Portal, where they were analysed in Stata 16.1 SE. A 2-parameter (2-PL) logistic IRT model was estimated to evaluate each item of the SCCAI for its informativeness (discrimination). A revised scale was generated and re-assessed following systematic removal of items.

RESULTS

SCCAI data for 516 UC patients (41 years, SD = 15) treated in Oxford were examined. After initial item deletion (Erythema nodosum, Pyoderma gangrenosum), a 7-item scale was estimated. Discrimination values (information) ranged from 0.41 to 2.52 indicating selected item inefficiency with three items < 1.70 which is a suggested discriminatory value for optimal efficiency. Systematic item deletions found that a 4-item scale (bowel frequency day; bowel frequency nocturnal; urgency to defaecation; rectal bleeding) was more informative and discriminatory of trait severity (discrimination values of 1.50 to 2.78). The 4-item scale possesses higher scalability and unidimensionality, suggesting that the responses to items are either direct endorsement (patient selection by symptom) or non-endorsement of the trait (disease activity).

CONCLUSION

Reduction of the SCCAI from the original 9-item scale to a 4-item scale provides optimum trait information that will minimise response burden. This new 4-item scale needs validation against other measures of disease activity such as faecal calprotectin, endoscopy and histopathology.

Recent advances in design of antimicrobial peptides and polypeptides toward clinical translation

The recent outbreaks of infectious diseases caused by multidrug-resistant pathogens have sounded a piercing alarm for the need of new effective antimicrobial agents to guard public health. Among different types of candidates, antimicrobial peptides (AMPs) and the synthetic mimics of AMPs (SMAMPs) have attracted significant enthusiasm in the past thirty years, due to their unique membrane-active antimicrobial mechanism and broad-spectrum antimicrobial activity. The extensive research has brought many drug candidates into clinical and pre-clinical development. Despite tremendous progresses have been made, several major challenges inherent to current design strategies have slowed down the clinical translational development of AMPs and SMAMPs. However, these challenges also triggered many efforts to redesign and repurpose AMPs. In this review, we will first give an overview on AMPs and their synthetic mimics, and then discuss the current status of their clinical translation. Finally, the recent advances in redesign and repurposing AMPs and SMAMPs are highlighted.

Review: Lessons Learned From Clinical Trials Using Antimicrobial Peptides (AMPs)

Antimicrobial peptides (AMPs) or host defense peptides protect the host against various pathogens such as yeast, fungi, viruses and bacteria. AMPs also display immunomodulatory properties ranging from the modulation of inflammatory responses to the promotion of wound healing. More interestingly, AMPs cause cell disruption through non-specific interactions with the membrane surface of pathogens. This is most likely responsible for the low or limited emergence of bacterial resistance against many AMPs. Despite the increasing number of antibiotic-resistant bacteria and the potency of novel AMPs to combat such pathogens, only a few AMPs are in clinical use. Therefore, the current review describes (i) the potential of AMPs as alternatives to antibiotics, (ii) the challenges toward clinical implementation of AMPs and (iii) strategies to improve the success rate of AMPs in clinical trials, emphasizing the lessons we could learn from these trials.

LC-MS/MS assay coupled with carboxylic acid magnetic bead affinity capture to quantitatively measure cationic host defense peptides (HDPs) in complex matrices with application to preclinical pharmacokinetic studies

Synthetic host defense peptides (HDP) are a new class of promising therapeutic agents with potential application in a variety of diseases. RP-182 is a 10mer synthetic HDP design, which selectively reduces M2-like tumor associated macrophages via engagement with the cell surface lectin receptor MRC1/CD206 and is currently being developed as an innate immune defense regulator to improve anti-tumor immunity in immunologically cold tumors. Herein, we describe a sensitive and specific liquid chromatography (LC) coupled to quadrupole electron spray tandem mass spectrometry method to measure positively charged HDPs and HDP peptide fragments in complex biological matrices. Carboxylic acid magnetic beads were used as an affinity-capturing agent to extract the positively charged RP-182 from both mouse plasma and tissue homogenates. Beads were eluted with 0.1% (v/v) formic acid and chromatographic separation was achieved on a Waters 2.1 × 100 mm, 3.5 μm XSelect Peptide CSH C18 column with a Vanguard pre-column of the same phase. MS/MS was performed on a Thermo TSQ Quantiva triple quadrupole mass spectrometer operating in Selected Reaction Monitoring (SRM) mode fragmenting the plus three parent ion 458.9⁺³ and monitoring ions 624.0⁺², 550.5⁺², and 597.3⁺¹ for RP-182 and 462.4⁺³ > 629.1⁺², 555.5⁺², and 607.3⁺¹ for isotopic RP-182 standard. The assay had good linearity ranging from 1 ng to 1000 ng in mouse plasma with the lower limit of detection for RP-182 at 1 ng in mouse plasma with good intra- and inter-sample precision and accuracy. Recovery ranged from 66% to 77% with minimum matrix effects. The method was successfully applied to an abbreviated pharmacokinetic study in mice after single IP injection of RP-182. The method was successfully tested on a second HDP, the 17mer D4E1, and the cationic human peptide hormone ghrelin suggesting that it might be a general sensitive method applicable to quantifying HDP peptides that are difficult to extract.

Histologic Healing Rates of Medical Therapies for Ulcerative Colitis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

Histologic remission is a potentially valuable means of assessing disease activity and treatment response in ulcerative colitis (UC). However, the efficacy of existing therapies to achieve this outcome is unclear. We performed a systematic review and meta-analysis of histologic outcomes in UC randomized controlled trials and examined the relationship between histologic and endoscopic outcomes.

METHODS

MEDLINE, EMBASE, CENTRAL, and the Cochrane IBD Register were searched for randomized controlled trials of aminosalicylates, corticosteroids, immunosuppressives, biologics, and small molecules. Histologic and endoscopic remission and response data were independently extracted and pooled using binomial-normal random-effect or fixed-effect models. Pooled efficacy estimates were calculated as risk ratios (RRs) using the Mantel-Haenszel method. Univariable and multivariable random-effect meta-regression models examined factors associated with histologic remission.

RESULTS

Seventy-four studies (68 induction and 7 maintenance) were identified. Topical aminosalicylate enemas [37.2%, 95% confidence interval (CI), 29.0-46.3] and suppositories (44.9%, 95% CI, 28.9-62.3) had the highest induction of histologic remission rates. Aminosalicylate enemas (RR = 4.14, 95% CI, 2.35-7.31), aminosalicylate suppositories (RR = 3.94, 95% CI, 1.26-12.32), and budesonide multimatrix (RR = 1.47, 95% CI 1.08-1.99) had higher histologic remission rates than placebo. Data were lacking for biologics and immunosuppressives. The pooled histologic remission rate for placebo in induction studies was 10.4% (95% CI, 7.1-15.2). Histologic and endoscopic remission correlated strongly (r = 0.66; 95% CI, 0.50-0.78). In multivariate analysis of placebo-arm data, less severe clinical disease activity and corticosteroid use were associated with higher histologic remission rates. Similarly, mild clinical disease activity was associated with higher histologic remission rates when active-arm data were analyzed.

CONCLUSIONS

Histologic remission rates for current UC treatments ranged from 15.0% to 44.9% according to drug class and patient population with the highest rates observed for topical aminosalicylates. Placebo remission rates were low with relatively narrow CIs. These data provide benchmarks to inform future trial design. Histologic remission is a potential treatment target in clinical practice.

Current and Emerging Evidence for Toll-Like Receptor Activation in Sjögren's Syndrome

While the importance of Toll-like receptor (TLR) signaling is well established in many autoimmune diseases, the role of TLR activation in Sjögren's syndrome (SS) is poorly understood. Studies in mice and humans reveal that TLRs are potent mediators of inflammation in SS. TLRs are expressed and functional in salivary tissue, and TLRs in peripheral blood cells of SS patients are also upregulated and hyperresponsive to ligation. In this review, we will detail observations in mouse models regarding the importance of TLR activation in both local and systemic disease. We will then discuss studies in SS patients that provide evidence of the importance of TLR-mediated signaling in disease. While the ligands that activate TLRs in the context of SS are unknown, emerging data suggest that damage-associated molecular patterns (DAMPs) may be significant drivers of the chronic and unremitting inflammation that is characteristic of SS. We will discuss putative DAMPs that may be of clinical significance in disease. Therapies that target TLR signaling cascades will likely reduce both exocrine-specific and systemic manifestations of SS.

Antiinflammatory peptides: current knowledge and promising prospects

BACKGROUND

Inflammation is part of the regular host reaction to injury or infection caused by toxic factors, pathogens, damaged cells, irritants, and allergens. Antiinflammatory peptides (AIPs) are present in all living organisms, and many peptides from herbal, mammalian, bacterial, and marine origins have been shown to have antimicrobial and/or antiinflammatory properties.

METHODS

In this study, we investigated the effects of antiinflammatory peptides on inflammation, and highlighted the underlying mechanisms responsible for these effects.

RESULTS

In multicellular organisms, including humans, AIPs constitute an essential part of their immune system. In addition, numerous natural and synthetic AIPs are effective immunomodulators and can interfere with signal transduction pathways involved in inflammatory cytokine expression. Among them, some peptides such as antiflammin, N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), and those derived from velvet antler proteins, bee venom, horse fly salivary gland, and bovine β-casein have received considerable attention over the past few years.

CONCLUSION

This article presents an overview on the major properties and mechanisms of action associated with AIPs as immunomodulatory, chemotactic, antioxidant, and antimicrobial agents. In addition, the results of various studies dealing with effects of AIPs on numerous classical models of inflammation are reviewed and discussed.

Review article: novel oral-targeted therapies in inflammatory bowel disease

BACKGROUND

There is a great unmet clinical need for efficacious, tolerable, economical and orally administrated drugs for the treatment of inflammatory bowel disease (IBD). New therapeutic avenues have become possible including the development of medications that target specific genetic pathways found to be relevant in other immune mediated diseases.

AIMS

To provide an overview of recent clinical trials for new generation oral targeted medications that may have a future role in IBD management.

METHODS

Pubmed and Medline searches were performed up to 1 March 2018 using keywords: "IBD", "UC", "CD", "inflammatory bowel disease" "ulcerative colitis", "Crohn's disease" in combination with "phase", "study", "trial" and "oral". A manual search of the clinical trial register, article reference lists, abstracts from meetings of Digestive Disease Week, United European Gastroenterology Week and ECCO congress were also conducted.

RESULTS

In randomised controlled trials primary efficacy endpoints were met for tofacitinib (JAK 1/3 inhibitor-phase III), upadacitinib (JAK 1 inhibitor-phase II) and AJM300 (α4-integrin antagonist-phase II) in ulcerative colitis. Ozanimod (S1P receptor agonist-phase II) also demonstrated clinical remission. For Crohn's disease, filgotinib (JAK1 inhibitor-phase II) met primary endpoints and laquinimod (quinolone-3-carboxide small molecule-phase II) was also efficacious. Trials using mongersen (SMAD7 inhibitor) and vidofludimus (dihydroorotate dehydrogenase inhibitor) have been halted.

CONCLUSIONS

This is potentially the start of an exciting new era in which multiple therapeutic options are at the disposal of physicians to treat IBD on an individualised basis. Head-to-head studies with existing treatments and longer term safety data are needed for this to be possible.

Peptide mimic for influenza vaccination using nonnatural combinatorial chemistry

Polypeptide vaccines effectively activate human T cells but suffer from poor biological stability, which confines both transport logistics and in vivo therapeutic activity. Synthetic biology has the potential to address these limitations through the generation of highly stable antigenic "mimics" using subunits that do not exist in the natural world. We developed a platform based on D-amino acid combinatorial chemistry and used this platform to reverse engineer a fully artificial CD8+ T cell agonist that mirrored the immunogenicity profile of a native epitope blueprint from influenza virus. This nonnatural peptide was highly stable in human serum and gastric acid, reflecting an intrinsic resistance to physical and enzymatic degradation. In vitro, the synthetic agonist stimulated and expanded an archetypal repertoire of polyfunctional human influenza virus-specific CD8+ T cells. In vivo, specific responses were elicited in naive humanized mice by subcutaneous vaccination, conferring protection from subsequent lethal influenza challenge. Moreover, the synthetic agonist was immunogenic after oral administration. This proof-of-concept study highlights the power of synthetic biology to expand the horizons of vaccine design and therapeutic delivery.

Placebo response and remission rates in randomised trials of induction and maintenance therapy for ulcerative colitis

BACKGROUND

It is important to minimize placebo rates in randomised controlled trials (RCTs) to efficiently detect treatment differences between interventions. Historically, high placebo rates have been observed in clinical trials of ulcerative colitis (UC). A better understanding of factors influencing placebo rates may lead to more informed clinical trial design.

OBJECTIVES

A systematic review and meta-analysis was conducted to evaluate placebo response and remission rates in RCTs evaluating UC treatments in adult patients.

SEARCH METHODS

Electronic databases (i.e. MEDLINE, EMBASE, and CENTRAL) were searched from inception to 1 March 2017 with no language restrictions applied. Reference lists and conference proceedings of major gastroenterology meetings were also handsearched to identify additional studies.

SELECTION CRITERIA

Placebo-controlled RCTs of adult patients with UC treated with corticosteroids, aminosalicylates, immunosuppressives or biologics were eligible, provided enrolment and outcome assessment was conducted using the Ulcerative Colitis Disease Activity Index (UCDAI) or the Mayo Clinic Score. The minimum trial duration was two weeks for induction trials and four months maintenance trials.

DATA COLLECTION AND ANALYSIS

Pairs of authors independently determined study eligibility and extracted data with any disagreements resolved through consensus. Outcomes of interest included the proportion of patients with clinical response and remission. Trial characteristics such as the design, participant demographics and disease history, interventions, and enrolment and assessment criteria were also recorded. The methodological quality of the included studies was evaluated using the Cochrane risk of bias tool. Pooled placebo response and remission rates and 95% confidence intervals (95% CI) were calculated using a binomial normal model for proportions. Induction of remission and maintenance studies were pooled separately. The impact of study-level characteristics on placebo response and remission rates was investigated using mixed-effects meta-regression analyses with logits of event rates as the outcome variables. An assessment of pooled placebo rates over time was conducted using a cumulative meta-analysis based on date of publication. Publication bias was examined using funnel plots.

MAIN RESULTS

The screening process identified 61 included studies which encompass 58 induction phases (5111 patients randomised to placebo) and 12 maintenance phases (1579 patients randomised to placebo). For induction trials, the pooled estimate of placebo response was 33% (95% CI 30% to 36%) while the pooled estimate of placebo remission was 12% (95% CI 9% to 15%). For maintenance trials, the pooled estimate of placebo response was 23% (95% CI 19% to 28%) while the pooled estimate of placebo remission was 17% (95% CI 10% to 27%).Studies enrolling patients with more active disease confirmed objectively by endoscopy were associated with significantly lower placebo remission and response rates than trials enrolling patients with less active disease (27% versus 4%, OR 2.60, 95% CI 1.25 to 5.42, P = 0.01 for UCDAI endoscopy sub score ≥1 versus ≥ 2 for remission; and 27% versus 4%, OR 1.70, 95% CI 1.02 to 2.82, P = 0.02 for UCDAI endoscopy sub score greater than or equal to one versus greater than or equal to two for response). With respect to drug class, the lowest placebo response and remission rates were observed in trials evaluating corticosteroids (23%; 95% CI 19 to 29%, and 5%; 95% CI 2 to 11%, respectively). Trials of biologics had the highest placebo response rate (35%; 95% CI 30 to 41%), while trials evaluating aminosalicylates had the highest placebo remission rate (18%; 95% CI 12 to 24%). Disease duration of greater than five years prior to enrolment was associated with a significantly lower placebo response rate compared to disease duration of less than or equal to five years (29% versus 47%, respectively; OR 0.54, 95% CI 0.32 to 0.92, P = 0.02). The requirement of a minimum rectal bleeding score for study eligibility was associated with an increased placebo response rate compared to studies that did not use rectal bleeding for trial eligibility (37% versus 32%, respectively; OR 1.70, 95% CI 1.02 to 2.82, P = 0.02). Finally, the time point of primary outcome assessment was found to be significantly associated with placebo remission rates such that every one week increment in endpoint assessment was associated with a 6% increase in the placebo remission rate (OR 1.06, 95% CI 1.02 to 1.10, P = 0.01).Cumulative meta-analysis indicated a consistent increase in the placebo response rate from 1987 to 2007 (from 13% to 33%), although rates have remained constant from 2008 to 2015 (32% to 34%). Similarly, placebo remission rates increased from 1987 to 2007 (5% to 14%) but have remained constant from 2008 to 2015 (12 to 14%). On meta-regression, there were no statistically significant differences between the 1987-2007 and 2008-2015 point estimates for both response (P = 0.81) and remission (P = 0.32).

AUTHORS' CONCLUSIONS

Placebo response and remission rates vary according to endoscopic disease severity and rectal bleeding score at trial entry, class of agent, disease duration, and the time point at which the primary outcome was measured. These observations have important implications for the design and conduct of future clinical trials in UC and will help researchers design trials, determine required sample sizes and also provide useful information about trial design features which should be considered when planning new trials.

Innate immunity in Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease of exocrine tissue that primarily affects women. Although patients typically experience xerostomia and xerophthalmia, numerous systemic disease manifestations are seen. Innate immune hyperactivity is integral to many autoimmune diseases, including SS. Results from SS mouse models suggest that innate immune dysregulation drives disease and this is a seminal event in SS pathogenesis. Findings in SS patients corroborate those in mouse models, as innate immune cells and pathways are dysregulated both in exocrine tissue and in peripheral blood. We will review the role of the innate immune system in SS pathogenesis. We will discuss the etiology of SS with an emphasis on innate immune dysfunction. Moreover, we will review the innate cells that mediate inflammation in SS, the pathways implicated in disease, and the potential mechanisms governing their dysregulation. Finally, we will discuss emerging therapeutic approaches to target dysregulated innate immune signaling in SS.

Machine learning for predicting lifespan-extending chemical compounds

Increasing age is a risk factor for many diseases; therefore developing pharmacological interventions that slow down ageing and consequently postpone the onset of many age-related diseases is highly desirable. In this work we analyse data from the DrugAge database, which contains chemical compounds and their effect on the lifespan of model organisms. Predictive models were built using the machine learning method random forests to predict whether or not a chemical compound will increase Caenorhabditis elegans' lifespan, using as features Gene Ontology (GO) terms annotated for proteins targeted by the compounds and chemical descriptors calculated from each compound's chemical structure. The model with the best predictive accuracy used both biological and chemical features, achieving a prediction accuracy of 80%. The top 20 most important GO terms include those related to mitochondrial processes, to enzymatic and immunological processes, and terms related to metabolic and transport processes. We applied our best model to predict compounds which are more likely to increase C. elegans' lifespan in the DGIdb database, where the effect of the compounds on an organism's lifespan is unknown. The top hit compounds can be broadly divided into four groups: compounds affecting mitochondria, compounds for cancer treatment, anti-inflammatories, and compounds for gonadotropin-releasing hormone therapies.

Histologic scoring indices for evaluation of disease activity in ulcerative colitis

BACKGROUND

Disease activity can be determined using clinical, endoscopic or histologic criteria in patients with ulcerative colitis (UC). Persistent disease activity is associated with poor outcomes. Histologic disease activity has been shown to be associated with relapse, colectomy and colorectal cancer. The ability to objectively evaluate microscopic disease activity using histology is important for both clinical practice and clinical trials. However, the operating properties of the currently available histologic indices remain unclear.

OBJECTIVES

A systematic review was undertaken to identify and evaluate the development and operating characteristics of histologic disease activity indices used to assess disease activity in people with ulcerative colitis.

SEARCH METHODS

We searched MEDLINE, EMBASE, PubMed, CENTRAL and the Cochrane IBD Review Group Specialized Trials Register from inception to 2 December 2016 for applicable studies. There were no language or document type restrictions.

SELECTION CRITERIA

Any study design (e.g. randomized controlled trials, cohort studies, case series) that evaluated a histologic index in patients with UC were considered for inclusion. Eligible patients were adults (> 18 years), diagnosed with UC using conventional clinical, radiographic, endoscopic and histologic criteria.

DATA COLLECTION AND ANALYSIS

Two authors (MHM and CEP) independently reviewed the titles and abstracts of the studies identified from the literature search. A standardized form was used to assess eligibility of trials for inclusion and for data extraction.Two authors (MHM and CEP) independently extracted and recorded data, which included the number of patients enrolled, number of patients per treatment arm, patient characteristics including age and gender distribution, and the name of the histologic index. Outcomes (i.e. intra-rater reliability, inter-rater reliability, internal consistency, content validity, criterion validity, construct validity, responsiveness, and feasibility) were recorded for each trial.

MAIN RESULTS

In total, 126 reports describing 30 scoring indices were identified through the screening process. Eleven of the 30 scoring indices have undergone some form of index validation. Intra-rater reliability was assessed for eight scoring indices. Inter-rater reliability was evaluated for all 11 of the scoring indices. Three of the indices underwent content validation. Two of the included scoring indices assessed criterion validity. Six of the included scoring indices explored content validity. Two of the included scoring indices were tested for responsiveness.

AUTHORS' CONCLUSIONS

The Nancy Index and the Robarts Histopathology Index have undergone the most validation in that four operating properties including reliability, content validity, construct validity (hypothesis testing) and criterion validity have been tested. However, none of the currently available histologic scoring indices have been fully validated. In order to determine the optimal endpoint for histologic healing in UC, more research is required. The optimal index would need to be fully validated.

Defining endoscopic response and remission in ulcerative colitis clinical trials: an international consensus

BACKGROUND

Recently, endpoints for clinical trials have been changing from measuring clinical response to mucosal healing in ulcerative colitis. Endoscopic evaluation is the current gold standard to assess mucosal lesions and has become a major measure of therapeutic efficacy in addition to patients reported outcomes.

AIM

To achieve consensus on endoscopic definitions of remission and response for clinical trials in patients with ulcerative colitis.

METHODS

In reaching the current international recommendations on an International Organization For the Study of Inflammatory Bowel Disease (IOIBD) initiative, we first performed a systematic review of technical aspects of endoscopic scoring systems. Then, to achieve consensus on endoscopic definitions of remission and response for clinical trials, we conducted a two-round vote using a Delphi-style process among fifteen specialists in the field of inflammatory bowel diseases.

RESULTS

The literature review showed that many endoscopic indices have been proposed to evaluate disease activity in ulcerative colitis; most are unvalidated and arbitrary definitions have been used in clinical trials for defining endoscopic response or remission. At the end of the voting process, the investigators ranked initially the Ulcerative Colitis Endoscopic Index of Severity (UCEIS) 0 for the definition of endoscopic remission, and a decrease in Mayo endoscopic score ≥1 grade or a decrease in UCEIS ≥2 points for the definition of endoscopic response in ulcerative colitis.

CONCLUSIONS

These international recommendations represent the first consensus on measurement indices for endoscopic outcomes in ulcerative colitis. They should be subject to prospective testing in clinical trials of ulcerative colitis.

Novel antimicrobial peptide-modified azithromycin-loaded liposomes against methicillin-resistant Staphylococcus aureus

Infections caused by multidrug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), have become a public threat; therefore, development of new antimicrobial drugs or strategies is urgently required. In this study, a new antibacterial peptide DP7-C (Chol-suc-VQWRIRVAVIRK-NH2) and DP7-C-modified azithromycin (AZT)-loaded liposomes (LPs) are developed for the treatment of MRSA infection, and it was found that DP7-C inserted into the LP lipid bilayer not only functioned as a carrier to encapsulate the antibiotic AZT but also synergized the antibacterial effect of the encapsulated AZT. In vitro assays showed that DP7-C-modified LPs possessed sustained drug release profile and immune regulatory effect and did not show obvious cytotoxicity in mammal cells, but they did not possess direct antibacterial activity in vitro. In vivo studies revealed that DP7-C-modified LPs did not exhibit obvious side effects or toxicity in mice but were able to significantly reduce the bacterial counts in an MRSA-infectious mouse model and possessed high antibacterial activity. In particular, DP7-C-modified AZT-loaded LPs showed more positive therapeutic effects than either DP7-C-modified blank LPs or nonmodified AZT-loaded LPs treatment alone. Molecular mechanism studies demonstrated that DP7-C formulations effectively upregulated the production of anti-inflammatory cytokines and chemokines without inducing harmful immune response, suggesting that DP7-C was synergistic with AZT against the bacterial infection by activating the innate immune response. Most importantly, although DP7-C activated the innate immune response, it did not possess direct antibacterial activity in vitro, indicating that DP7-C did not possess the potential to induce bacteria resistance. The findings indicate that DP7-C-modified AZT-loaded LPs developed in this study have a great potential required for the clinical treatment of MRSA infections.

Isomeranzin suppresses inflammation by inhibiting M1 macrophage polarization through the NF-κB and ERK pathway

Macrophage polarization plays an important role in inflammation. Regulation of the polarization has been reported to be effective therapeutics for various kinds of inflammatory diseases. The aims of the present study were to investigate the anti-inflammatory property of isomeranzin isolating from Murraya exotica as well as potential molecular mechanisms. Results showed that isomeranzin specifically reduced the M1 macrophage-associated pro-inflammatory cytokines through down-regulation of NF-κB and ERK signals. Immunoprecipitation and RNA silencing indicated suppression of isomeranzin in NF-κB activation was relying on the decreasing of TRAF6 ubiquitination. In vivo studies showed isomeranzin evidently inhibited LPS-induced sepsis for rising survival rate, improving tissue damage and lessening inflammatory cytokines. In accordance with in vitro studies, isomeranzin significantly blocked expression of p-p65 and p-ERK in lung and liver tissues. Moreover, isomeranzin ameliorated DSS and TNBS-induced colitis due to its anti-inflammatory effects. Taken together, isomeranzin suppressed inflammatory diseases by controlling M1 macrophage polarization through the NF-κB and ERK pathway.

The Impact of Clinical Information on the Assessment of Endoscopic Activity: Characteristics of the Ulcerative Colitis Endoscopic Index Of Severity [UCEIS]

BACKGROUND AND AIMS

To determine whether clinical information influences endoscopic scoring by central readers using the Ulcerative Colitis Endoscopic Index of Severity [UCEIS; comprising 'vascular pattern', 'bleeding', 'erosions and ulcers'].

METHODS

Forty central readers performed 28 evaluations, including 2 repeats, from a library of 44 video sigmoidoscopies stratified by Mayo Clinic Score. Following training, readers were randomised to scoring with ['unblinded', n = 20, including 4 control videos with misleading information] or without ['blinded', n 20] clinical information. A total of 21 virtual Central Reader Groups [CRGs], of three blinded readers, were created. Agreement criteria were pre-specified. Kappa [κ] statistics quantified intra- and inter-reader variability.

RESULTS

Mean UCEIS scores did not differ between blinded and unblinded readers for any of the 40 main videos. UCEIS standard deviations [SD] were similar [median blinded 0.94, unblinded 0.93; p = 0.97]. Correlation between UCEIS and visual analogue scale [VAS] assessment of overall severity was high [r blinded = 0.90, unblinded = 0.93; p = 0.02]. Scores for control videos were similar [UCEIS: p ≥ 0.55; VAS: p ≥ 0.07]. Intra- [κ 0.47-0.74] and inter-reader [κ 0.40-0.53] variability for items and full UCEIS was 'moderate'-to-'substantial', with no significant differences except for intra-reader variability for erosions and ulcers [κ blinded: 0.47 vs unblinded: 0.74; p 0.047]. The SD of CRGs was lower than for individual central readers [0.54 vs 0.95; p < 0.001]. Correlation between blinded UCEIS and patient-reported symptoms was high [stool frequency: 0.76; rectal bleeding: 0.82; both: 0.81].

CONCLUSIONS

The UCEIS is minimally affected by knowledge of clinical details, strongly correlates with patient-reported symptoms, and is a suitable instrument for trials. CRGs performed better than individuals.

Taming inflammation by targeting cytokine signaling: new perspectives in the induction of transplantation tolerance

Transplantation tolerance remains an elusive goal, partly due to limitations in our understanding of the interplay between inflammatory mediators and their role in the activation and regulation of T lymphocytes. Although multiple mechanisms acting both centrally and peripherally are responsible for tolerance induction, the signaling pathways leading to activation or regulation of adaptive immunity are often complex, branched, redundant and modulated by the microenvironment's inflammatory milieu. Accumulating evidence clearly indicates that inflammatory cytokines limit the tolerogenic potential of immunomodulatory protocols by supporting priming of the immune system and counteracting regulatory mechanisms, ultimately promoting rejection. In this review, we summarize recent progress in the development of novel therapeutics to manipulate this inflammatory environment and achievements in targeted inhibition of inflammatory cytokine signaling. Ultimately, robust transplant tolerance induction will probably require a multifaceted, holistic approach that integrates the various mechanisms of tolerance induction, incorporates the dynamic alterations in costimulatory requirements of alloreactive T cells, while maintaining endogenous mechanisms of immune regulation.

The role of Toll-like receptors in multiple sclerosis and possible targeting for therapeutic purposes

The interaction between the immune and nervous systems suggests invaluable mechanisms for several pathological conditions, especially neurodegenerative disorders. Multiple sclerosis (MS) is a potentially disabling chronic autoimmune disease, characterized by chronic inflammation and neurodegenerative pathology of the central nervous system. Toll-like receptors (TLRs) are an important family of receptors involved in host defense and in recognition of invading pathogens. The role of TLRs in the pathogenesis of autoimmune disorders such as MS is only starting to be uncovered. Recent studies suggest an ameliorative role of TLR3 and a detrimental role of other TLRs in the onset and progression of MS and experimental autoimmune encephalomyelitis, a murine model of MS. Thus, modulating TLRs can represent an innovative immunotherapeutic approach in MS therapy. This article outlines the role of these TLRs in MS, also discussing TLR-targeted agonist or antagonists that could be used in the different stages of the disease.

Early events in Sjögren's Syndrome pathogenesis: the importance of innate immunity in disease initiation

Sjögren's Syndrome (SS) is a debilitating autoimmune disease that primarily affects women. Patients with SS experience dry eyes and dry mouth in addition to systemic disease manifestations, including arthritis, peripheral neuropathy and pulmonary fibrosis. As in many autoimmune diseases, the inciting factors that precipitate SS are poorly understood. Patients with SS have periductal and perivascular lymphocytic infiltration of salivary and lacrimal tissue, and this is a hallmark of disease. While this infiltration is well characterized, the pathologic events that precede and cause this inflammatory cell recruitment are unknown. Although few studies have examined SS salivary tissue prior to disease onset, there is strong evidence for innate immune hyperactivity. Accordingly, processes such as apoptosis of glandular tissue, heightened inflammatory cytokine and chemokine production, and toll-like receptor (TLR) activation are described in early disease and are each linked to innate immune activation in murine models of disease and SS patients. This review will explore the relationship between innate immunity and SS pathogenesis prior to overt disease onset and discuss therapeutic strategies to mitigate disease progression in SS patients.

Histologic evaluation of ulcerative colitis: a systematic review of disease activity indices

BACKGROUND

Ulcerative colitis (UC) is an idiopathic inflammatory disorder. Currently, the main goals of treatment are to induce and maintain clinical and/or endoscopic remission. However, evidence indicates that persistent disease activity on colonic biopsies in the setting of clinical or endoscopic remission is an independent predictor of poor outcomes. A number of previous studies have proposed histologic indices for use in specific trials of UC. The aim of this study was to systematically review the existing histological indices for UC and assess their potential use in both patient management and clinical trials.

METHODS

We performed a systematic review of histological indices evaluating disease activity in UC. MEDLINE (Ovid), EMBASE (Ovid), PubMed, the Cochrane Library (CENTRAL), and Digestive Diseases Week (DDW) abstracts of randomized and/or controlled trials clinical trials were searched from inception to February 2013 for applicable studies. Data from these studies were reviewed and analyzed.

RESULTS

After systematically applying inclusion criteria, we identified 108 scientific articles including 88 clinical studies and 21 related clinical reviews. Eighteen indices of histological activity in UC were identified and reviewed.

CONCLUSIONS

Although multiple histological scoring indices for assessment of UC disease activity currently exist, none of these instruments were developed using a formal validation process and their operating properties remain poorly understood. Future studies are needed to address this deficiency.

Reliability and initial validation of the ulcerative colitis endoscopic index of severity

BACKGROUND & AIMS

We studied the reliability of the previously described Ulcerative Colitis Endoscopic Index of Severity (UCEIS) and validated it with an independent cohort of investigators.

METHODS

We created a new library of 57 videos of flexible sigmoidoscopy and stratified them based on disease severity. Twenty-five investigators were each randomly assigned to assess 28 videos (which included 4 duplicates to assess intraobserver reliability). Investigators were blinded to clinical details except for 2 of 4 duplicated videos (to assess the impact of knowledge of symptoms on assessment). Three descriptors ("vascular pattern", "bleeding", and "erosions and ulcers") comprising the UCEIS were scored with a visual analogue scale (VAS) to assess overall severity. Intrainvestigator and interinvestigator agreement was characterized by κ statistical analysis; reliability ratios were used to compare VAS and UCEIS scores.

RESULTS

There was a high level of correlation between UCEIS scores and overall assessment of severity (correlation coefficient, 0.93). Internal consistency (Cronbach α analysis) was 0.86. Intrainvestigator and interinvestigator reliability ratios for UCEIS scores were 0.96 and 0.88, respectively. Intrainvestigator agreement in determination of the UCEIS score was good (κ = 0.72), with individual descriptors ranging from a κ of 0.47 (for bleeding) to 0.87 (for vascular pattern). Interinvestigator agreement in determination of UCEIS scores was moderate (κ = 0.50), with descriptors ranging from a κ of 0.48 (for bleeding) to 0.54 (for vascular pattern). Intrainvestigator variability in determining UCEIS scores did not change appreciably when a video was presented with clinical details.

CONCLUSIONS

The UCEIS and its components show satisfactory intrainvestigator and interinvestigator reliability. Among investigators, the UCEIS accounted for a median of 86% of the variability in evaluation of overall severity on the VAS when assessing the endoscopic severity of UC and was unaffected by knowledge of clinical details.

Toll-like receptors as therapeutic targets for autoimmune connective tissue diseases

Autoimmune connective tissue diseases (ACTDs) are a family of consistent systemic autoimmune inflammatory disorders, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc) and Sjögren's syndrome (SS). IL-1R-like receptors (TLRs) are located on various cellular membranes and sense exogenous and endogenous danger-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs), playing a critical role in innate immune responses. During the past decade, the investigation of TLRs in inflammatory autoimmune diseases has been fruitful. In this report, we review the significant biochemical, physiological and pathological studies of the key functions of TLRs in ACTDs. Several proteins in the TLR signaling pathways (e.g., IKK-2 and MyD88) have been identified as potential therapeutic targets for the treatment of ACTDs. Antibodies, oligodeoxyribonucleotides (ODNs) and small molecular inhibitors (SMIs) have been tested to modulate TLR signaling. Some drug-like SMIs of TLR signaling, such as RDP58, ST2825, ML120B and PHA-408, have demonstrated remarkable potential, with promising safety and efficacy profiles, which should warrant further clinical investigation. Nonetheless, one should bear in mind that all TLRs exert both protective and pathogenic functions; the function of TLR4 in inflammatory bowel disease represents such an example. Therefore, an important aspect of TLR modulator development involves the identification of a balance between the suppression of disease-inducing inflammation, while retaining the beneficiary host immune response.

Alarmins: awaiting a clinical response

Alarmins are endogenous molecules that are constitutively available and released upon tissue damage and activate the immune system. Current evidence indicates that uncontrolled and excessive release of alarmins contributes to the dysregulated processes seen in many inflammatory and autoimmune conditions, as well as tumorigenesis and cancer spread. Conversely, alarmins have also been found to play a major role in the orchestration of tissue homeostasis, including repair and remodeling in the heart, skin, and nervous system. Here, we provide an update and overview on alarmins, highlighting the areas that may benefit from this clinical translation.

Peptide-based approaches to treat lupus and other autoimmune diseases

After a long period where the potential of therapeutic peptides was let into oblivion and even dismissed, there is a revival of interest in peptides as potential drug candidates. Novel strategies for limiting metabolism and improve their bioavailability, and alternative routes of administration have emerged. This resulted in a large number of peptide-based drugs that are now being marketed in different indications. Regarding autoimmunity, successful data have been reported in numerous mouse models of autoimmune inflammation, yet relatively few clinical trials based on synthetic peptides are currently underway. This review reports on peptides that show much promises in appropriate mouse models of autoimmunity and describes in more detail clinical trials based on peptides for treating autoimmune patients. A particular emphasis is given to the 21-mer peptide P140/Lupuzor that has completed successfully phase I, phase IIa and phase IIb clinical trials for systemic lupus erythematosus.

Protease-resistant peptide design-empowering nature's fragile warriors against HIV

Peptides have great potential as therapeutic agents, but their use is often limited by susceptibility to proteolysis and their resulting in vivo fragility. In this review, we focus on peptidomimetic approaches to produce protease-resistant peptides with the potential for greatly improved clinical utility. We focus on the use of mirror-image (D-peptide) and ß-peptides as two leading approaches with distinct design principles and challenges. Application to the important and difficult problem of inhibiting HIV entry illustrates the current state-of-the-art in peptidomimetic technologies. We also summarize future directions for this field and highlight remaining obstacles to widespread use of protease-resistant peptides.

Designing antimicrobial peptides: form follows function

Multidrug-resistant bacteria are a severe threat to public health. Conventional antibiotics are becoming increasingly ineffective as a result of resistance, and it is imperative to find new antibacterial strategies. Natural antimicrobials, known as host defence peptides or antimicrobial peptides, defend host organisms against microbes but most have modest direct antibiotic activity. Enhanced variants have been developed using straightforward design and optimization strategies and are being tested clinically. Here, we describe advanced computer-assisted design strategies that address the difficult problem of relating primary sequence to peptide structure, and are delivering more potent, cost-effective, broad-spectrum peptides as potential next-generation antibiotics.

Multifunctional cationic host defence peptides and their clinical applications

With the rapid rise in the emergence of bacterial strains resistant to multiple classes of antimicrobial agents, there is an urgent need to develop novel antimicrobial therapies to combat these pathogens. Cationic host defence peptides (HDPs) and synthetic derivatives termed innate defence regulators (IDRs) represent a promising alternative approach in the treatment of microbial-related diseases. Cationic HDPs (also termed antimicrobial peptides) have emerged from their origins as nature's antibiotics and are widely distributed in organisms from insects to plants to mammals and non-mammalian vertebrates. Although their original and primary function was proposed to be direct antimicrobial activity against bacteria, fungi, parasites and/or viruses, cationic HDPs are becoming increasingly recognized as multifunctional mediators, with both antimicrobial activity and diverse immunomodulatory properties. Here we provide an overview of the antimicrobial and immunomodulatory activities of cationic HDPs, and discuss their potential application as beneficial therapeutics in overcoming infectious diseases.

Blocking lymphocyte localization to the gastrointestinal mucosa as a therapeutic strategy for inflammatory bowel diseases

Lymphocyte migration (homing) to specific tissues has an important role during protective and pathological immune responses, including inflammatory bowel diseases. Lymphocytes use integrin α4β7 and the chemokine receptor CCR9 to localize to the gastrointestinal mucosa; their respective ligands, mucosal addressin cell adhesion molecule-1 and CCL25, are displayed on endothelial cells in intestinal postcapillary venules. Although gastrointestinal-homing receptors are required for lymphocyte migration to the intestine in the noninflamed steady state, their role during inflammation is a matter of debate. Reagents designed to block interactions between these receptors and their ligands have had variable degrees of success in animal models of inflammatory bowel diseases and patients. We discuss the mechanisms involved in lymphocyte localization to the intestinal mucosa and how they can be applied to therapy for inflammatory bowel diseases.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

Protective effects of glycyrrhizic acid by rectal treatment on a TNBS-induced rat colitis model

Objectives

The research compared rectal and oral treatments with glycyrrhizic acid for trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats.

Methods

Wistar rats were randomly divided into seven groups: one normal and six with colitis, including TNBS, glycyrrhizic acid (2, 10 and 50 mg/kg, rectally treated and 10 mg/kg, orally treated) and sulfasalazine (positive control, 225 mg/kg rectally treated) groups. Colitis was induced by colonic administration of TNBS in 30% ethanol.

Key findings

There were significant pathological changes in colon in TNBS-treated groups, and rectal glycyrrhizic acid significantly attenuated colitis. Myeloperoxidase, tumour necrosis factor-α and interleukin-1β of colon tissue or serum in the rectal glycyrrhizic acid groups were markedly reduced when compared with the TNBS group, and lower than in the orally treated glycyrrhizic acid group. It was further noted that, in vitro, glycyrrhizic acid (up to 100 µg/ml) inhibited interleukin-6 and elevated interleukin-10 production in lipopolysaccharide-activated macrophages, and significantly inhibited proliferation of spleen lymphocytes, suggesting the immunoregulatory function of glycyrrhizic acid.

Conclusions

Rectally administered glycyrrhizic acid has significant protective effects against TNBS-induced colitis in rats, and the rectal route may be a complementary treatment for inflammatory bowel disease.

The latest developments in synthetic peptides with immunoregulatory activities

In the past few years, many researches have provided us with much data demonstrating the abilities of synthetic peptides to impact immune response in vitro and in vivo. These peptides were designed according to the structure of some important protein molecules which play a key role in immune response, so they act with specific targets. The class I and II MHC-derived peptides inhibit the TCR recognition of antigen peptide-MHC complex. Rationally designed CD80 and CD154-binding peptides block the interaction between cell surface costimulatory molecules on antigen-presenting cells (APCs) and T cells. Some peptides were designed to inhibit the activities of cell signal proteins, including JNK, NF-κB and NFAT. Some peptide antagonists competitively bind to important cytokines and inhibit their activities, such as TNF-α, TGF-β and IL-1β inhibitory peptides. Adhesion molecule ICAM-1 derived peptides block the T cell adhesion and activation. These immunoregulatory peptides showed therapeutic effect in several animal models, including collagen-induced arthritis (CIA), autoimmune cystitis model, murine skin transplant model and cardiac allograft model. These results give us important implications for the development of a novel therapy for immune mediated diseases.