Proton pump inhibitors exacerbate NSAID-induced small intestinal injury by inducing dysbiosis

Evaluation of anti-inflammatory potential of the leaves of Wendlandia heynei (Schult.) Santapau & Merchant in Sprague Dawley rat

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of W. heynei (family: Rubiaceae) are used by the folklore in swelling, wounds and body aches. In this study anti-inflammatory potential of W. heynei leaves has been evaluated during in vitro studies and in rat.

METHODS

Methanol extract of the leaves of W. heynei (WHLM) and its fractions; n-hexane (WHLH), chloroform (WHLC), ethyl acetate (WHLE), n-butanol (WHLB) and residual soluble aqueous (WHLA) were screened for phytochemical analysis and several active constituents (alkaloids, flavonoids, saponins, tannins, terpenoids, β-carotene and lycopene) were also quantified. Heat induced albumin denaturation assay and in vitro cell cultures was carried out for in vitro anti-inflammatory activity, while various in vivo assays like TPA induced ear edema, croton oil induced anus edema, formalin and carrageenan-induced hind paw edema was investigated in Sprague-Dawley rats. Alterations on levels of tumor necrosis factor (TNF-α), Interleukin-1β (IL-1β), IL-6 and prostaglandins (PGE₂) induced with WHLE was studied in serum after carrageenan induced paw edema in rat. Meanwhile, the dose dependent WHLE inhibition of NFκB pathway via regulation of the phosphorylation of IKKs, IκBα, and p65 subunit was studied in LPS-induced rat peritoneal macrophages. On account of marked anti-inflammatory activity of WHLE its bioactive components were analyzed by HPLC-DAD analysis.

RESULTS

The phytochemical analysis yielded alkaloids, saponins, tannins, coumarins, glycosides, quinones and vitamin C in WHLM and in all fractions. Fraction (WHLE) was enriched with alkaloids (20.20 ± 2.5%), flavonoids (25.26 ± 2.11%) and tannins (307.2 ± 2.03 mg of GAE/g of extract), while terpenoids (21.60 ± 1.65%) were the major constituents of WHLH. Ethyl acetate fraction convincingly protected heat induced albumin denaturation. WHLE exhibited highest edema inhibition in models of TPA-induced ear edema (74.51 ± 2.05) and croton oil-induced anal edema (75.38 ± 2.83). The pretreatment with WHLE significantly (p < 0.05) reduced the paw edema with formalin (78.99 ± 2.26%) assessed after 6 h and in carrageenan (75.71 ± 4.46%) was detected after 4 h. Level of anti-inflammatory markers; IL-1β, IL-6, TNF-α and PGE₂ in carrageenan induced paw edema in serum of rat was significantly (p < 0.001) decreased with WHLE pretreatment to rat. WHLE significantly inhibited the NFκB by reducing the phosphorylation of IKKs, IκBα, and p65 subunit in LPS-induced inflammation in rat peritoneal macrophages. HPLC-DAD analysis of WHLE indicated the presence of rutin, gallic acid, catechin, caffeic acid and myricetin.

CONCLUSIONS

It is concluded that WHLM fractions have marked anti-inflammatory activity and this study endorsed the folklore use of W. heynei leaves for swelling related disorders.

Proton pump inhibitors and dysbiosis: Current knowledge and aspects to be clarified

Proton pump inhibitors (PPIs) are common medications within the practice of gastroenterology. These drugs, which act through the irreversible inhibition of the hydrogen/potassium pump (H+/K+-ATPase pump) in the gastric parietal cells, are used in the treatment of several acid-related disorders. PPIs are generally well tolerated but, through the long-term reduction of gastric acid secretion, can increase the risk of an imbalance in gut microbiota composition (i.e., dysbiosis). The gut microbiota is a complex ecosystem in which microbes coexist and interact with the human host. Indeed, the resident gut bacteria are needed for multiple vital functions, such as nutrient and drug metabolism, the production of energy, defense against pathogens, the modulation of the immune system and support of the integrity of the gut mucosal barrier. The bacteria are collected in communities that vary in density and composition within each segment of the gastrointestinal (GI) tract. Therefore, every change in the gut ecosystem has been connected to an increased susceptibility or exacerbation of various GI disorders. The aim of this review is to summarize the recently available data on PPI-related microbiota alterations in each segment of the GI tract and to analyze the possible involvement of PPIs in the pathogenesis of several specific GI diseases.

Changing epidemiology and etiology of upper and lower gastrointestinal bleeding

Upper gastrointestinal bleeding (UGIB) develops in the oesophagus, stomach or duodenum and has an incidence of 47/100,000. Lower GIB (LGIB) develops in the small bowel, colon or anorectum and has an incidence of 33/100,000. Where the incidence of UGIB has fallen, driven by helicobacter pylori eradication and the use of proton pump inhibitors, the incidence of LGIB may be increasing. Interventions such as early endoscopy, risk assessment and national guidelines have improved clinical outcomes but have had limited impact on the economic burden of GIB. Previously LGIB was thought to be less severe than UGIB, but contemporary data suggest that patients with LGIB tend to have a longer length of hospital stay and may be at higher risk of death or re-bleeding.

NSAID-induced enteropathy: the current state of the problem

The review analyzes the main etiological and pathogenetic mechanisms of the development of NSAID-enteropathy. Particular attention is paid to the role of intestinal microbiota in the manifestation and progression of NSAID-enteropathy. The special role of probiotics in the prevention and treatment of NSAIDs enteropathy is considered.

Eicosanoids in the gastrointestinal tract

Eicosanoids play important roles in modulating inflammation throughout the body. The gastrointestinal (GI) tract, in part because of its intimate relationship with the gut microbiota, is in a constant state of low-grade inflammation. Eicosanoids like PGs, lipoxins and leukotrienes play essential roles in maintenance of mucosal integrity. On the other hand, in some circumstances, these mediators can become major drivers of inflammatory processes when the lining of the GI tract is breached. Drugs such as nonsteroidal anti-inflammatories, by altering the production of various eicosanoids, can dramatically impact the ability of the GI tract to respond appropriately to injury. Disorders such as inflammatory bowel disease appear to be driven in part by altered production of eicosanoids. Several classes of drugs have been developed that target eicosanoids. LINKED ARTICLES: This article is part of a themed section on Eicosanoids 35 years from the 1982 Nobel: where are we now? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.8/issuetoc.

NSAID-induced small intestinal mucosal injury: Mechanism, prevention and treatment

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in clinical practice. It was well known in the past that the main side effect of NSAIDs was gastric mucosal injury. However, with the advancement of the diagnostic and therapeutic technology, NSAIDs have been found to cause much more severe damage to the small intestinal mucosa than we expected in recent years. Therefore, it is of great significance to elucidate the mechanism for NSAIDs to cause small intestinal mucosal injury to aid the clinical prevention and treatment of this condition. This paper aims to review the progress in the research of the mechanism, prevention, and treatment of NSAID-induced small intestinal mucosal injury.

Lack of Small Intestinal Dysbiosis Following Long-Term Selective Inhibition of Cyclooxygenase-2 by Rofecoxib in the Rat

Intestinal dysbiosis is linked to numerous gastrointestinal disorders, including inflammatory bowel diseases. It is a question of debate if coxibs, selective inhibitors of cyclooxygenase (COX)-2, cause dysbiosis. Therefore, in the present study, we aimed to determine the effect of long-term (four weeks) selective inhibition of COX-2 on the small intestinal microbiota in the rat. In order to avoid mucosal damage due to topical effects and inflammation-driven microbial alterations, rofecoxib, a nonacidic compound, was used. The direct inhibitory effect of rofecoxib on the growth of bacteria was ruled out in vitro. The mucosa-sparing effect of rofecoxib was confirmed by macroscopic and histological analysis, as well as by measuring the intestinal levels of cytokines and tight junction proteins. Deep sequencing of bacterial 16S rRNA revealed that chronic rofecoxib treatment had no significant influence on the composition and diversity of jejunal microbiota. In conclusion, this is the first demonstration that long-term selective inhibition of COX-2 by rofecoxib does not cause small intestinal dysbiosis in rats. Moreover, inhibition of COX-2 activity is not likely to be responsible per se for microbial alterations caused by some coxibs, but other drug-specific properties may contribute to it.

The Spectrum of Small Intestinal Lesions in Patients with Unexplained Iron Deficiency Anemia Detected by Video Capsule Endoscopy

Background and objectives: Video-capsule endoscopy (VCE) has shown a large range (38⁻83%) of diagnostic yield in unexplained iron deficiency anemia (IDA) and obscure-occult bleeding. Therefore, we retrospectively investigated the VCE-detected spectrum and the prevalence of small bowel injuries and associated risk factors in inpatients with both of the above reported conditions. Methods: We selected inpatients with IDA (hemoglobin <12 g/dL in women, <13 g/dL in men) and obscure-occult bleeding. We excluded VCE indications other than IDA. Complete medical histories and laboratory tests were collected. All subjects underwent PillCam SB2/SB3. The VCE feature Lewis score was calculated when appropriate. We used the t-test and Fisher's exact test for continuous and categorical variables, respectively, in univariate analysis. For multivariate analysis, we used binomial logistic regression. Results: We retrieved 109 patients (female:male ratio of 53:56; age 63.4 ± 18.9 years). Eighty patients (73.4%) showed ≥1 small bowel lesions. The Lewis score was calculated in 41 patients: 13 (31.7%) showed a mild (<135) and 28 (68.3%) a moderate-severe (135⁻790 and >790, respectively) score. In univariate analysis, the small bowel transit time (6.2 ± 2.9 versus 5.2 ± 2.1 h; p = 0.049) and non-steroidal anti-inflammatory drug use for at least two weeks (17.5% versus 0%; p = 0.01) were significantly higher in subjects with injuries. These associations were not confirmed at multivariate analysis. The severity of a lesion directly correlated with proton pump inhibitor (PPI) use and duration (not confirmed in multivariate analysis). VCE can reveal the source of obscure-occult bleeding in a high percentage of unexplained IDAs. A wide spectrum of endoscopic pictures may be found. Known as well as supposed risk factors for small bowel lesions may be detected.

The H2S-Releasing Naproxen Derivative ATB-346 and the Slow-Release H2S Donor GYY4137 Reduce Intestinal Inflammation and Restore Transit in Postoperative Ileus

Objective: Intestinal inflammation triggers postoperative ileus (POI), commonly seen after abdominal surgery and characterized by impaired gastrointestinal transit; when prolonged, this leads to increased morbidity. Hydrogen sulfide (H2S) is recognized as an important mediator of many (patho)physiological processes, including inflammation, and is now investigated for anti-inflammatory application. Therefore, the aim of this study was to investigate the effect of the H2S-releasing naproxen derivative ATB-346, developed to reduce gastrointestinal injury by naproxen, and the slow-release H2S donor GYY4137 on intestinal inflammation and delayed gastrointestinal transit in murine POI. Methods: C57Bl6J mice were fasted for 6 h, anesthetized and after laparotomy, POI was induced by compressing the small intestine with two cotton applicators for 5 min (intestinal manipulation; IM). GYY4137 (50 mg/kg, intraperitoneally), ATB-346 (16 mg/kg, intragastrically) or naproxen (10 mg/kg, intragastrically) were administered 1 h before IM. At 24 h postoperatively, gastrointestinal transit was assessed via fluorescent imaging, and mucosa-free muscularis segments were prepared for later analysis. Inflammatory parameters and activity of inducible nitric oxide synthase (iNOS) and cyclo-oxygenase (COX)-2 were measured. Histological examination of whole tissue sections was done on hematoxylin-eosin stained slides. Results: Pre-treatment with GYY4137 (geometric center; GC: 7.6 ± 0.5) and ATB-346 (GC: 8.4 ± 0.3) prevented the delayed transit induced by IM (GC: 3.6 ± 0.5 vs. 9.0 ± 0.4 in non-operated controls) while naproxen only partially did (GC: 5.9 ± 0.5; n = 8 for all groups). GYY4137 and ATB-346 significantly reduced the IM-induced increase in muscular myeloperoxidase (MPO) activity and protein levels of interleukin (IL)-6, IL-1β and monocyte chemotactic protein 1; the reduction by naproxen was less pronounced and only reached significance for MPO activity and IL-6 levels. All treatments significantly reduced the increase in COX-2 activity caused by IM, whereas only GYY4137 significantly reduced the increase in iNOS activity. Naproxen treatment caused significant histological damage of intestinal villi. Conclusion: The study shows that naproxen partially prevents POI, probably through its inhibitory effect on COX-2 activity. Both ATB-346 and GYY4137 were more effective, the result with GYY4137 showing that H2S per se can prevent POI.

A fatal case of bowel obstruction caused by non-steroidal anti-inflammatory drug enteropathy

We report the case of a 34-year-old woman who died after presenting to hospital with a 2-month history of vomiting, abdominal pain and diarrhea. Subsequent inquiries revealed that she had a history of non-steroidal anti-inflammatory drug (NSAID) abuse, and the autopsy revealed stricture formation consistent with being caused by NSAID enteropathy.

Obesity Aggravates Acute Pancreatitis via Damaging Intestinal Mucosal Barrier and Changing Microbiota Composition in Rats

Obesity may aggravate acute pancreatitis (AP) through damaging the intestinal mucosal barrier (IMB). The underlying mechanism remains unclear. This study was aimed to provide further data to clarify the mechanism. 48 rats were divided into 4 groups: 1) normal control (NC), chow-fed rats with sham operation, 2) no-obese rats with AP (NAP), chow-fed rats with taurocholate infusion, 3) obese control (OC), high-fat diet (HFD)-fed rats with sham operation, and 4) obese rats with AP (OAP), HFD-fed rats with taurocholate infusion. Pancreatic pathologic score (11.39 ± 1.76 vs. 14.11 ± 1.05, p = 0.005), intestinal permeability to FD4 (0.91 ± 0.25 μg/ml vs. 7.06 ± 3.67 μg/ml, p < 0.001), serum leptin (10.25 ± 5.59 ng/ml vs. 79.73 ± 38.44 ng/ml, p < 0.001) and ileal apoptosis (2.05 ± 0.73% vs. 4.53 ± 2.28%, p = 0.006) were significantly higher in OAP than in NAP group. The intestinal bacterial richness (Chao 1 and OTUs) was significantly lower in OAP than in NAP rats. The higher abundance of Proteobacteria and reduced proportions of intestinal Actinobacteria, Allobaculum and Barnesiella were detected in OAP group. Obesity may result in decreased intestinal leptin/ObR-b binding, distinct phylogenetic clusters of ileal bacterial communities, increased intestinal inflammatory injury and the insufficient intestinal epithelial cells proliferation during AP attack. Pancreatic injury was aggravated due to obesity associated dysfunction of IMB.

The frequency and clinical and endoscopic features of mixed NSAIDs-induced gastrointestinal injuries

Non-steroidal anti-inflammatory drugs (NSAIDs) can cause undesirable reactions in all parts of the gastrointestinal tract (GIT). However, the frequency of mixed injuries of various GIT parts due to the use of these drugs has not been investigated.Objective: to estimate the frequency of mixed NSAID-induced injuries of the upper GIT, small and large intestine.Patients and methods. A total of 112 patients (62.5% were women) (mean age, 56.2±14.6 years) with rheumatic diseases who had regularly taken NSAIDs were examined. All the patients underwent esophagogastroduodenoscopy and video colonoscopy. Video capsule endoscopy was performed in 35 patients with signs of NSAID-induced gastropathy.Results and discussion. The signs of NSAID-induced gastropathy (gastric and duodenal erosions and/or ulcers) were found in 43.8% of patients; those of NSAID-induced enteropathy (small bowel hemorrhages, erosions, and ulcers) were present in 68.6%; and those of NSAIDinduced colopathy (colonic hemorrhages, erosions, and ulcers) were in 14.3%. The concurrence of NSAID-induced gastro- and colonopathy was present in 28.6% of the patients (odds ratio 12.2; 95% confidence interval, 2.619–56.84); that of NSAID-induced gastro-, entero-, and colopathy was in 10 (20.4% of all the patients with NSAID-induced gastropathy). There was a significant association of the risk of mixed pathology in all GIT parts with the diagnosis of spondylarthritis, the presence of abdominal pain, the signs of dysbiosis and bacterial overgrowth syndrome, as well as with the carriage of CYP2C19 gene polymorphism (the CYP2C19*17*1/*17 allele).Conclusion. Mixed injury of various GIT parts due to the use of NSAIDs is a frequent and serious pathology that requires comprehensive diagnostic tests and combined use of preventive therapies with different mechanisms of action.

Microbiome-The Missing Link in the Gut-Brain Axis: Focus on Its Role in Gastrointestinal and Mental Health

The central nervous system (CNS) and the human gastrointestinal (GI) tract communicate through the gut-brain axis (GBA). Such communication is bi-directional and involves neuronal, endocrine, and immunological mechanisms. There is mounting data that gut microbiota is the source of a number of neuroactive and immunocompetent substances, which shape the structure and function of brain regions involved in the control of emotions, cognition, and physical activity. Most GI diseases are associated with altered transmission within the GBA that are influenced by both genetic and environmental factors. Current treatment protocols for GI and non-GI disorders may positively or adversely affect the composition of intestinal microbiota with a diverse impact on therapeutic outcome(s). Alterations of gut microbiota have been associated with mood and depressive disorders. Moreover, mental health is frequently affected in GI and non-GI diseases. Deregulation of the GBA may constitute a grip point for the development of diagnostic tools and personalized microbiota-based therapy. For example, next generation sequencing (NGS) offers detailed analysis of microbiome footprints in patients with mental and GI disorders. Elucidating the role of stem cell⁻host microbiome cross talks in tissues in GBA disorders might lead to the development of next generation diagnostics and therapeutics. Psychobiotics are a new class of beneficial bacteria with documented efficacy for the treatment of GBA disorders. Novel therapies interfering with small molecules involved in adult stem cell trafficking are on the horizon.

ACVIM consensus statement: Support for rational administration of gastrointestinal protectants to dogs and cats

The gastrointestinal (GI) mucosal barrier is continuously exposed to noxious toxins, reactive oxygen species, microbes, and drugs, leading to the development of inflammatory, erosive, and ultimately ulcerative lesions. This report offers a consensus opinion on the rational administration of GI protectants to dogs and cats, with an emphasis on proton pump inhibitors (PPIs), histamine type-2 receptor antagonists (H2 RAs), misoprostol, and sucralfate. These medications decrease gastric acidity or promote mucosal protective mechanisms, transforming the management of dyspepsia, peptic ulceration, and gastroesophageal reflux disease. In contrast to guidelines that have been established in people for the optimal treatment of gastroduodenal ulcers and gastroesophageal reflux disease, effective clinical dosages of antisecretory drugs have not been well established in the dog and cat to date. Similar to the situation in human medicine, practice of inappropriate prescription of acid suppressants is also commonplace in veterinary medicine. This report challenges the dogma and clinical practice of administering GI protectants for the routine management of gastritis, pancreatitis, hepatic disease, and renal disease in dogs and cats lacking additional risk factors for ulceration or concerns for GI bleeding. Judicious use of acid suppressants is warranted considering recent studies that have documented adverse effects of long-term supplementation of PPIs in people and animals.

Proton pump inhibitors reduce the accuracy of faecal immunochemical test for detecting advanced colorectal neoplasia in symptomatic patients

Background

The faecal immunochemical test (FIT) is used in colorectal cancer (CRC) screening and for the detection of advanced colorectal neoplasia (AN) in symptomatic patients, but its accuracy could be improved. Our objective was to assess the impact of proton pump inhibitors (PPI) on the accuracy of the FIT in the detection of AN, namely advanced colorectal adenoma and CRC.

Methods and findings

We performed a prospective study of 1002 individuals referred for a diagnostic colonoscopy at Bellvitge University Hospital from September 2011 through to October 2012. An exhaustive interview was performed by a gastroenterologist, prescription drug dispensing database was reviewed and the patient was given a FIT prior to colonoscopy. The positivity threshold of FIT used was ≥ 20 μg Hb/g feces and the main outcome was AN. AN was detected in 13.2% (133) of patients. The accuracy of FIT for detecting AN in the PPI users and non-PPI users were: sensitivity 43.0% vs 65.6%, P = 0.009; specificity 86.9% vs 92.3%, P = 0.010; and, predictive positive value 34.4% vs 55.5%, P = 0.007, respectively. In multivariate analysis, adjusting for potential confounders, PPIs were associated with false positives in AN detection by FIT (OR 1.63 CI 95% 1.02–2.59, P < 0.037). The ROC curve for the FIT in the detection of AN in the PPI users and non-PPI users was 0.68 (CI 95% 0.61–0.76) and 0.85 (CI 95% 0.79–0.90).

Conclusions

PPI therapy reduces the accuracy of FIT for detecting AN in symptomatic patients.

Differential effects of selective and non-selective cyclooxygenase inhibitors on fecal microbiota in adult horses

Non-steroidal anti-inflammatory drugs (NSAIDs) are routinely used in both veterinary and human medicine. Gastrointestinal injury is a frequent adverse event associated with NSAID use and evidence suggests that NSAIDs induce gastrointestinal microbial imbalance (i.e., dysbiosis) in both animals and people. It is unknown, however, whether cyclooxygenase (COX)-2-selective NSAIDs induce dysbiosis, or if this phenomenon occurs in horses administered any class of NSAIDs. Therefore, our objectives were to determine whether the composition and diversity of the fecal microbiota of adult horses were altered by NSAID use, and whether these effects differed between non-selective and COX-2-selective NSAIDs. Twenty-five adult horses were randomly assigned to 1 of 3 groups: control (n = 5); phenylbutazone (n = 10); or, firocoxib (n = 10). Treatments were administered for 10 days. Fecal samples were collected every 5 days for 25 days. DNA was extracted from feces and the 16S rRNA gene amplified and sequenced to determine the composition of the microbiota and the inferred metagenome. While the fecal microbiota profile of the control group remained stable over time, the phenylbutazone and firocoxib groups had decreased diversity, and alteration of their microbiota profiles was most pronounced at day 10. Similarly, there were clear alterations of the inferred metagenome at day 10 compared to all other days, indicating that use of both non-selective and selective COX inhibitors resulted in temporary alterations of the fecal microbiota and inferred metagenome. Dysbiosis associated with NSAID administration is clinically relevant because dysbiosis has been associated with several important diseases of horses including abdominal pain (colic), colitis, enteric infections, and laminitis.

Proton pump inhibitor usage and nonsteroidal anti-inflammatory drugs-associated small intestinal injury: How to balance risks and benefits

Proton pump inhibitors (PPIs) are widely used in the treatment of acid-related diseases and can effectively prevent upper gastrointestinal damage associated with nonsteroidal anti-inflammatory drugs (NSAIDs). However, recent studies have shown that PPIs cannot protect from NSAIDs-associated small bowel injury, and may even aggravate intestinal injury by altering the intestinal flora. This article will discuss the risks associated with the combined use of NSAIDs and PPIs, as well as how to balance risks and benefits of PPIs treatment, and provide a brief review of strategies for the prevention of NSAIDs-associated small bowel injury.

Usefulness of small bowel reexamination in obscure gastrointestinal bleeding patients with negative capsule endoscopy findings: Comparison of repeat capsule endoscopy and double-balloon enteroscopy

Background

Although capsule endoscopy (CE) is a noninvasive diagnostic tool for patients with obscure gastrointestinal bleeding (OGIB), bleeding lesions are often not detected. No strategies have been established to determine whether CE or double-balloon enteroscopy (DBE) should be performed after negative CE.

Methods

Among 652 patients who underwent CE for OGIB, a total of 359 patients had negative findings. Of these, 41 and 48 patients underwent repeat CE and DBE for small bowel reexamination, respectively. We compared the rate of positive findings between the two groups. The findings were considered positive if mucosal break, vascular lesion, tumor, or active bleeding was observed.

Results

The rate of positive findings in the repeat CE group was significantly higher than that in the DBE group (73.2% vs. 39.6%; p = 0.001). Logistic regression analysis showed that the repeat CE group was significantly associated with positive findings (odds ratio (OR), 4.2; 95% confidence interval (CI), 1.7-10.2; p = 0.002). Inverse probability of treatment-weighted analysis revealed that repeat CE was significantly associated with positive findings (OR, 4.4; 95% CI, 1.6-12.2; p = 0.004).

Conclusions

Reexamination via CE appears to have more diagnostic value than DBE for OGIB patients with negative CE findings.

Exosomes derived from high-glucose-stimulated Schwann cells promote development of diabetic peripheral neuropathy

Schwann cells actively interact with axons of dorsal root ganglia (DRG) neurons. Exosomes mediate intercellular communication by transferring their biomaterials, including microRNAs (miRs) into recipient cells. We hypothesized that exosomes derived from Schwann cells stimulated by high glucose (HG) exosomes accelerate development of diabetic peripheral neuropathy and that exosomal cargo miRs contribute to this process. We found that HG exosomes contained high levels of miR-28, -31a, and -130a compared to exosomes derived from non-HG-stimulated Schwann cells. In vitro, treatment of distal axons with HG exosomes resulted in reduction of axonal growth, which was associated with elevation of miR-28, -31a, and -130a and reduction of their target proteins of DNA methyltransferase-3α, NUMB (an endocytic adaptor protein), synaptosome associated protein 25, and growth-associated protein-43 in axons. In vivo, administration of HG exosomes to sciatic nerves of diabetic db/db mice at 7 wk of age promoted occurrence of peripheral neuropathy characterized by impairment of nerve conduction velocity and induction of mechanic and thermal hypoesthesia, which was associated with substantial decreases in intraepidermal nerve fibers. Our findings demonstrate a functional role of exosomes derived from HG-stimulated Schwann cells in mediating development of diabetic peripheral neuropathy.-Jia, L., Chopp, M., Wang, L., Lu, X., Szalad, A., Zhang, Z. G. Exosomes derived from high-glucose-stimulated Schwann cells promote development of diabetic peripheral neuropathy.

Sex differences in NSAID-induced perturbation of human intestinal barrier function and microbiota

Intestinal barrier function and microbiota are integrally related and play critical roles in maintenance of host physiology. Sex is a key biologic variable for several disorders. Our aim was to determine sex-based differences in response to perturbation and subsequent recovery of intestinal barrier function and microbiota in healthy humans. Twenty-three volunteers underwent duodenal biopsies, mucosal impedance, and in vivo permeability measurement. Permeability testing was repeated after administration of indomethacin, then 4 to 6 wk after its discontinuation. Duodenal and fecal microbiota composition was determined using 16S rRNA amplicon sequencing. Healthy women had lower intestinal permeability and higher duodenal and fecal microbial diversity than healthy men. Intestinal permeability increases after indomethacin administration in both sexes. However, only women demonstrated decreased fecal microbial diversity, including an increase in Prevotella abundance, after indomethacin administration. Duodenal microbiota composition did not show sex-specific changes. The increase in permeability and microbiota changes normalized after discontinuation of indomethacin. In summary, women have lower intestinal permeability and higher microbial diversity. Intestinal permeability is sensitive to perturbation but recovers to baseline. Gut microbiota in women is sensitive to perturbation but appears to be more stable in men. Sex-based differences in intestinal barrier function and microbiome should be considered in future studies.-Edogawa, S., Peters, S. A., Jenkins, G. D., Gurunathan, S. V., Sundt, W. J., Johnson, S., Lennon, R. J., Dyer, R. B., Camilleri, M., Kashyap, P. C., Farrugia, G., Chen, J., Singh, R. J., Grover, M. Sex differences in NSAID-induced perturbation of human intestinal barrier function and microbiota.

Immunomodulatory interplay of the microbiome and therapy of rheumatic diseases

Modulation of the immune system by microbes, especially from the gastrointestinal tract, is increasingly considered a key factor in the onset, course and outcome of rheumatic diseases. The interplay of the microbiome, along with genetic predisposition and environmental exposure, is thought to be an important trigger for rheumatic diseases. Improved identification of the relationship of disease-specific genetic alterations and rheumatic diseases has potential diagnostic and therapeutic applications. Treatment of rheumatic disorders is influenced by microbial actions but this interplay can be challenging due to variable and unpredictable responses to therapies. Expanded knowledge of the microbiome now allows clinicians to more precisely select ideal medication regimens and to predict response to and toxicity from drugs. Rheumatic diseases and associated therapies were among the earliest microbiome interactions investigated, yet it is notable that current research is focused on clinical and immunological associations but, in comparison, a limited number of studies regarding the microbiome's impact on treatment for rheumatic diseases have been published. In the coming years, further knowledge of immunomodulating interactions between the microbiome and the immune system will aid our understanding of autoimmunity and will be increasingly important in selection of therapeutic agents for patients with autoimmune and rheumatic diseases. In this review, recent literature regarding the bidirectional immunomodulatory effects of the microbiome with rheumatic diseases and current understanding and gaps regarding the drug-microbiome interface in the management of these disorders is presented.

Dual antiplatelet therapy does not affect the incidence of low-dose aspirin-induced small intestinal mucosal injury in patients after percutaneous coronary intervention for coronary stenosis: a multicenter cross-sectional study

Although low-dose aspirin (LDA) is known to induce small intestinal mucosal injury, the effect of dual antiplatelet therapy (DAPT; LDA + clopidogrel) on small intestinal mucosa in patients after percutaneous coronary intervention (PCI) for coronary stenosis is unknown. Fifty-one patients with a history of PCI and LDA use were enrolled, and 45 eligible patients were analyzed. Patients were grouped based on DAPT (DAPT: n = 10 and non-DAPT: n = 35) and proton pump inhibitor (PPI) use (PPI user: n = 22 and PPI-free patients: n = 23) to compare small intestinal endoscopic findings. The relationship between LDA-use period and small intestinal endoscopic findings was also examined. Multivariate analysis was performed to identify risk factors for LDA-induced mucosal injury using age, sex, DAPT, PPI, gastric mucoprotective drug, and LDA-use period. The rate of small intestinal mucosal injury incidence did not significantly differ between DAPT and non-DAPT patients (50% vs 51.1%, respectively; p = 0.94), or PPI users and PPI-free patients (50% vs 52.2%, respectively; p = 0.88). Additionally, LDA-use period of ≤24 months (n = 15) yielded a significantly higher rate of small intestinal mucosal injury incidence than LDA-use period >24 months (n = 30) (80% vs 36.7%, respectively; p = 0.006). Multivariate analysis revealed that a LDA-use period of ≤24 months was a significant risk factor for small intestinal mucosal injury (odds ratio: 19.5, 95% confidence interval: 2.48–154.00, p = 0.005). Following PCI for coronary stenosis, neither DAPT nor PPI affected LDA-induced small intestinal mucosal injury. Moreover, patients who used LDA within the last 24 months were at a greater risk of small intestinal mucosal injury.

An intact microbiota is required for the gastrointestinal toxicity of the immunosuppressant mycophenolate mofetil

BACKGROUND

Mycophenolate mofetil (MMF) is commonly prescribed after transplantation and has major advantages over other immunosuppressive drugs, but frequent gastrointestinal (GI) side-effects limit its use. The mechanism(s) underlying MMF-related GI toxicity have yet to be elucidated.

METHODS

To investigate MMF-related GI toxicity, experimental mice were fed chow containing MMF (0.563%) and multiple indices of toxicity, including weight loss and colonic inflammation, were measured. Changes in intestinal microbial composition were detected using 16S rRNA Illumina sequencing, and downstream PICRUSt analysis was used to predict metagenomic pathways involved. Germ-free (GF) mice and mice treated with orally administered broad-spectrum antibiotics (ABX) were utilized to interrogate the importance of the microbiota in MMF-induced GI toxicity.

RESULTS

Mice treated with MMF exhibited significant weight loss, related to loss of body fat and muscle, and marked colonic inflammation. MMF exposure was associated with changes in gut microbial composition, as demonstrated by a loss of overall diversity, expansion of Proteobacteria (specifically Escherichia/Shigella), and enrichment of genes involved in lipopolysaccharide (LPS) biosynthesis, which paralleled increased levels of LPS in the feces and serum. MMF-related GI toxicity was dependent on the intestinal microbiota, as MMF did not induce weight loss or colonic inflammation in GF mice. Furthermore, ABX prevented and reversed MMF-induced weight loss and colonic inflammation.

CONCLUSIONS

An intact intestinal microbiota is required to initiate and sustain the GI toxicity of MMF. MMF treatment causes dynamic changes in the composition of the intestinal microbiota that may be a targetable driver of the GI side-effects of MMF.

Role of NRF2 in protection of the gastrointestinal tract against oxidative stress

The gastrointestinal tract is exposed to a variety of noxious factors, such as Helicobacter pylori, nonsteroidal anti-inflammatory drugs, gastric acid, ischemia-reperfusion, and mental stresses. Theses stressors generate free radicals within gastrointestinal tissues, causing organ injury and functional disturbance. Although the gastrointestinal tract can withstand such oxidative stresses to some extent by enhancing its antioxidant system via nuclear factor erythroid 2-related factor 2-Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1-mediated pathways, acute or chronic exposure to oxidative stress can cause several gastrointestinal tract disorders, such as inflammation, ulcers, cancers, and various functional disturbances. Recent studies have demonstrated that some natural compounds and drugs can upregulate the nuclear factor erythroid 2-related factor 2-mediated antioxidant system, ameliorating or preventing these disorders. Although these compounds may be useful as chemopreventive agents, sufficient evidence for their clinical efficacy has not yet been provided. In addition, it is important to note that excessive nuclear factor erythroid 2-related factor 2 stimulation can be harmful to human health, especially from the standpoint of tumor biology.

Rebleeding rate and risk factors in nonsteroidal anti-inflammatory drug-induced enteropathy

OBJECTIVE

Limited evidence is available on rebleeding due to nonsteroidal anti-inflammatory drugs (NSAIDs)-induced enteropathy. Previous studies have primarily analyzed endoscopic findings. Therefore, there is a need to evaluate their clinical implications for patients. This study aimed to evaluate the rebleeding rate and its related risk factors in patients with NSAIDs-induced enteropathy.

METHODS

Of 402 patients with obscure gastrointestinal bleeding who were evaluated with capsule endoscopy, 49 were diagnosed with NSAIDs-induced enteropathy. The clinical characteristics of the patients were retrospectively analyzed. The Charlson comorbidity index was used to stratify the comorbidities. For patients who used additional drugs that influenced their tendency to bleeding, the odds ratio was calculated and used for a quantitative comparison.

RESULTS

The rebleeding rate in patients with NSAIDs-induced enteropathy was 20.4%, within a mean duration of 23.4 months. Age ≥65 years (hazard ratio [HR] 8.628, 95% confidence interval [CI] 1.152-64.625), no additional use of mucoprotective agents (HR 11.712, 95% CI 1.278-76.098) and the continuation of NSAIDs after the first bleeding episode (HR 9.861, 95% CI 1.395-98.344) were independently related to rebleeding due to NSAIDs-induced enteropathy. The underlying comorbidities, drug-related rebleeding risk scores and therapeutic use of proton pump inhibitors were not significantly different (P = 0.209, 0.212 and 0.720, respectively).

CONCLUSIONS

Approximately one-fifth of patients with NSAIDs-induced enteropathy showed rebleeding within 2 years. A careful long-term follow-up should be offered to elderly patients with NSAIDs-induced enteropathy who need continuous NSAID treatment without the additional use of mucoprotective medications.

NSAIDs and the small bowel

PURPOSE OF REVIEW

The review describes the effects of NSAID gastrointestinal toxicity on the small bowel, wherein injury is as prevalent as in the gastroduodenum. This is well documented by capsule endoscopy, which also provides an endoscopic endpoint for novel treatment strategies.

RECENT FINDINGS

Appreciation of the prevalence of NSAID enteropathy has grown with capsule endoscopy and the use of composite end points that include obscure haemoglobin decreases in clinical studies. Along with dual cyclo-oxygenase isoform inhibition, gram-negative antigen presentation plays a role in the pathogenesis of NSAID enteropathy. The concomitant use of proton pump inhibitor (PPI) agents with both selective and nonselective NSAIDs in gastroduodenal protection exacerbates endoscopic enteropathy, which is thought to be due to intestinal dysbiosis. Strategies for small bowel mucosal protection include prostaglandin repletion and augmenting the intestinal flora.

SUMMARY

NSAID- related enteropathy is common and often presents subclinically. The most common presentation is anaemia, which may be less common in those on cyclo-oxygenase (COX)-2 inhibitors than nonselective NSAIDs. PPI use worsens NSAID enteropathy with more occult bleeding and ulceration and has been linked to gram-negative intestinal dysbiosis. If NSAID cessation is not possible, COX-2 inhibition without PPI therapy should be considered in patients with upper gastrointestinal risk factors. Mucoprotective agents such as misoprostol and rebamipide show promise and probiotics may have a future role.

Helicobacter pylori infection and occurrence of celiac disease in subjects HLA-DQ2/DQ8 positive: A prospective study

BACKGROUND

Celiac disease (CD) occurs in subjects positive for HLA-DQ2 and/or DQ8 gene loci at any age following ingestion of gluten-containing food. An increased permeability of the mucosa allows interactions between gliadin macromolecules and genetic factors. It has been observed that Helicobacter pylori has the ability to modulate the integrity of the duodenal epithelium. We aimed to determine whether H. pylori infection may enhance the occurrence of CD in genetically susceptible subjects.

MATERIALS AND METHODS

This was a prospective observational study. Patients undergoing upper endoscopy for any reason and positive for HLA-DQ2 and/or DQ8 haplotypes with or without CD were included. H. pylori infection was defined as a positive gastric histopathology and/or 13C-urea breath test. Prevalence of infection was compared between enrolled subjects with and without CD. Multiple logistic regression analysis, adjusting odds ratios for patient age, gender, smoking habit, residency, body mass index, and assumption of nonsteroidal anti-inflammatory drugs (NSAIDs) and proton-pump inhibitors (PPIs) were performed.

RESULTS

A total of 397 genetically susceptible individuals (mean age: 37.7 ± 15.3 years; 86% women) were enrolled between October 2014 and October 2017. There were 265 (68%) patients with a diagnosis of CD. Overall, the prevalence of H. pylori infection was 33% and was similar in patients with and without CD (32% vs 36%). Adjustment for all covariates did not reveal any significant association, although adjusted odds ratio (OR) for CD was higher in female (OR = 1.302), in patients H. pylori positive (OR = 1.277), followed by use of NSAIDs (OR = 1.126), respectively. The use of PPIs appeared to be mildly protective against CD (OR = 0.644).

CONCLUSION

Our study did not reveal any significant relationship between H. pylori and CD risk, even taking into account other confounders. More importantly, our findings do not support a "protective" role of H. pylori infection against CD, as previously reported. Therefore, there are no reasons to avoid eradication of H. pylori also in subject genetically susceptible for CD.

Drug-induced enterocolitis: Prevention and management in primary care

Drug-induced enterocolitis is a condition diagnosed with increasing frequency. It includes a variety of morphological and functional alterations of the small and large intestine as a consequence of exposure to pharmacological active compounds. A number of factors play a key role in this condition or participate in the onset of enterocolitis, which is the result of an interplay between the effect of the drug molecule and the tolerance of the bowel to damaging insults. The patient's age, gender, dose of drug, time of exposure, pharmaceutical preparation, drug-drug and drug-food interactions, gut barrier integrity, underlying intestinal conditions, and gut microbiota composition are all involved in the occurrence and extent of the injury. This review approaches the topic from the viewpoint of primary care, and focuses on epidemiology, mechanisms of damage, protective systems and diagnostic tools. Although the first-line therapeutic measure is the discontinuation of the drug, some options for prevention and treatment are discussed.

Residual Lesions on Capsule Endoscopy Is Associated with Postoperative Clinical Recurrence in Patients with Crohn's Disease

BACKGROUND

In order to optimize postoperative therapy in patients with Crohn's disease (CD), it is important to detect endoscopic recurrence preceding clinical recurrence. However, we have little knowledge about how high the rate of residual lesions is and whether these lesions have an influence on postoperative course or not.

AIMS

To assess residual lesions in small bowel immediately after surgery.

METHODS

Capsule endoscopy (CE) was performed immediately after surgery (< 3 months), and endoscopic activity was assessed using the Lewis score (LS) composed of the highest tertile score (in first, second, and third tertile) and the stenosis score (in whole small intestine). The relationship between these residual lesions and postoperative clinical recurrence was prospectively evaluated.

RESULTS

After assessing patency using a patency capsule, CE was performed in 25 patients. The mean LS was 751.3, and 84.0% (21/25) had endoscopic activity. These lesions were detected by preoperative examinations in 0% and by a serosal side view during surgery in 16.0%. Regarding the cumulative clinical recurrence rate according to endoscopic severity (normal, mild, and moderate-to-severe) immediately after surgery, no significant difference was found. However, comparing groups divided according to the highest tertile score, the cumulative clinical recurrence rate was significantly higher in the group with the highest third tertile score. Furthermore, patients with ulcers in the third tertile had a significantly higher recurrence rate.

CONCLUSIONS

Many cases with CD had endoscopic activity immediately after "curative" surgery. These residual lesions, especially in the distal small intestine, were associated with postoperative clinical recurrence.

Coprescribing proton-pump inhibitors with nonsteroidal anti-inflammatory drugs: risks versus benefits

Nonsteroidal anti-inflammatory drugs (NSAIDs) are often coadministered with proton-pump inhibitors (PPIs) to reduce NSAID-induced gastrointestinal (GI) adverse events. This coadministration is generally regarded as safe, and is included in many of the guidelines on NSAID prescription. However, recent evidence indicates that the GI risks associated with NSAIDs can be potentiated when they are combined with PPIs. This review discusses the GI effects and complications of NSAIDs and how PPIs may potentiate these effects, options for prevention of GI side effects, and appropriate use of PPIs in combination with NSAIDs.

Mechanisms of Damage to the Gastrointestinal Tract From Nonsteroidal Anti-Inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) can damage the gastrointestinal tract, causing widespread morbidity and mortality. Although mechanisms of damage involve the activities of prostaglandin-endoperoxide synthase 1 (PTGS1 or cyclooxygenase [COX] 1) and PTGS1 (COX2), other factors are involved. We review the mechanisms of gastrointestinal damage induction by NSAIDs via COX-mediated and COX-independent processes. NSAIDs interact with phospholipids and uncouple mitochondrial oxidative phosphorylation, which initiates biochemical changes that impair function of the gastrointestinal barrier. The resulting increase in intestinal permeability leads to low-grade inflammation. NSAID inhibition of COX enzymes, along with luminal aggressors, results in erosions and ulcers, with potential complications of bleeding, protein loss, stricture formation, and perforation. We propose a model for NSAID-induced damage to the gastrointestinal tract that includes these complex, interacting, and inter-dependent factors. This model highlights the obstacles for the development of safer NSAIDs.

Systematic review: human gut dysbiosis induced by non-antibiotic prescription medications

BACKGROUND

Global prescription drug use has been increasing continuously for decades. The gut microbiome, a key contributor to health status, can be altered by prescription drug use, as antibiotics have been repeatedly described to have both short-term and long-standing effects on the intestinal microbiome.

AIM

To summarise current findings on non-antibiotic prescription-induced gut microbiome changes, focusing on the most frequently prescribed therapeutic drug categories.

METHODS

We conducted a systematic review by first searching in online databases for indexed articles and abstracts in accordance with PRISMA guidelines. Studies assessing the intestinal microbiome alterations associated with proton pump inhibitors (PPIs), metformin, nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, statins and antipsychotics were included. We only included studies using culture-independent molecular techniques.

RESULTS

Proton pump inhibitors and antipsychotic medications are associated with a decrease in α diversity in the gut microbiome, whereas opioids were associated with an increase in α diversity. Metformin and NSAIDs were not associated with significant changes in α diversity. β diversity was found to be significantly altered with all drugs, except for NSAIDs. PPI use was linked to a decrease in Clotridiales and increase in Actinomycetales, Micrococcaceae and Streptococcaceae, which are changes previously implicated in dysbiosis and increased susceptibility to Clostridium difficile infection. Consistent results showed that PPIs, metformin, NSAIDs, opioids and antipsychotics were either associated with increases in members of class Gammaproteobacteria (including Enterobacter, Escherichia, Klebsiella and Citrobacter), or members of family Enterococcaceae, which are often pathogens isolated from bloodstream infections in critically ill patients. We also found that antipsychotic treatment, usually associated with an increase in body mass index, was marked by a decreased ratio of Bacteroidetes:Firmicutes in the gut microbiome, resembling trends seen in obese patients.

CONCLUSIONS

Non-antibiotic prescription drugs have a notable impact on the overall architecture of the intestinal microbiome. Further explorations should seek to define biomarkers of dysbiosis induced by specific drugs, and potentially tailor live biotherapeutics to counter this drug-induced dysbiosis. Many other frequently prescribed drugs should also be investigated to better understand the link between these drugs, the microbiome and health status.

Hydrogen sulfide: an agent of stability at the microbiome-mucosa interface

A diverse range of effects of the intestinal microbiota on mucosal defense and injury has become increasingly clear over the past decade. Hydrogen sulfide (H2S) has emerged as an important mediator of many physiological functions, including gastrointestinal mucosal defense and repair. Hydrogen sulfide is produced by gastrointestinal tract tissues and by bacteria residing within the gut and can influence the function of a wide range of cells. The microbiota also appears to be an important target of hydrogen sulfide. H2S donors can modify the gut microbiota, and the gastrointestinal epithelium is a major site of oxidation of microbial-derived H2S. When administered together with nonsteroidal anti-inflammatory drugs, H2S can prevent some of the dysbiosis those drugs induce, possibly contributing to the observed prevention of gastrointestinal damage. Exogenous H2S can also markedly reduce the severity of experimental colitis and plays important roles in modulating epithelial cell-mucus-bacterial interactions in the intestine, contributing to its ability to promote resolution of inflammation and repair of tissue injury. In this paper we review recent studies examining the roles of H2S in mucosal defense, the possibility that H2S can damage the gastrointestinal epithelium, and effects of H2S on the gut microbiota and on mucus and biofilm interactions in the context of intestinal inflammation.

Effect of egualen sodium hydrate on small-intestinal mucosal damage induced by low-dose aspirin: a prospective randomized clinical trial

Low-dose aspirin, which is widely used to reduce the risk of cardio- and cerebrovascular thrombosis, often induces gastroenteropathy by increasing the permeability of the mucosa. However, therapeutic strategies for patients with low-dose aspirin-induced small intestinal injury have not been determined. We evaluated the preventative effect of egualen sodium hydrate, a gastro-protective agent that suppresses indomethacin-induced small-intestinal damage in rats, against small-intestinal mucosal damage induced by low-dose aspirin in healthy adult male volunteers. Participants were randomly allocated to receive aspirin 100 mg/kg daily (control group, n = 10) or aspirin 100 mg/kg plus egualen sodium 30 mg daily (egualen sodium group, n = 10). Small intestinal mucosal injury was evaluated by capsule endoscopy two weeks after initiation of drug administration. Fecal analyses (occult blood test, immunochemical test, transferrin measurement and calprotectin measurement) were carried out before and after treatment. Egualen sodium significantly suppressed the total number of small intestinal injuries detected by capsule endoscopy and the positive ratio for the fecal occult blood test. Daily use of 30 mg of egualen sodium showed a preventative effect on low-dose aspirin-induced small intestinal injury. Since acid suppression therapy was reported to exacerbate NSAIDs-induced enteropathy via dysbiosis, egualen sodium may be useful for patients treated with low-dose aspirin.

Proton pump inhibitors are associated with accelerated development of cirrhosis, hepatic decompensation and hepatocellular carcinoma in noncirrhotic patients with chronic hepatitis C infection: results from ERCHIVES

BACKGROUND

Proton pump inhibitors are among the most commonly prescribed medications in the United States. Their safety in cirrhosis has recently been questioned, but their overall effect on disease progression in noncirrhotic patients with chronic liver disease remains unclear.

AIM

To determine the impact of proton pump inhibitors on the progression of liver disease in noncirrhotic patients with hepatitis C virus (HCV) infection.

METHODS

Using the electronically retrieved cohort of HCV-infected veterans (ERCHIVES) database, we identified all subjects who received HCV treatment and all incident cases of cirrhosis, hepatic decompensation and hepatocellular carcinoma. Proton pump inhibitor use was measured using cumulative defined daily dose. Multivariate Cox regression analysis was performed after adjusting univariate predictors of cirrhosis and various indications for proton pump inhibitor use.

RESULTS

Among 11 526 eligible individuals, we found that exposure to proton pump inhibitors was independently associated with an increased risk of developing cirrhosis (hazard ratio [HR]: 1.32; 95% confidence interval: [1.17, 1.49]). This association remained robust to sensitivity analysis in which only patients who achieved sustained virologic response were analysed as well as analysis excluding those with alcohol abuse/dependence. Proton pump inhibitor exposure was also independently associated with an increased risk of hepatic decompensation (HR: 3.79 [2.58, 5.57]) and hepatocellular carcinoma (HR: 2.01 [1.50, 2.70]).

CONCLUSIONS

In patients with chronic HCV infection, increasing proton pump inhibitor use is associated with a dose-dependent risk of progression of chronic liver disease to cirrhosis, as well as an increased risk of hepatic decompensation and hepatocellular carcinoma.

Meta-analysis: proton pump inhibitors moderately increase the risk of small intestinal bacterial overgrowth

The use of proton pump inhibitors (PPIs) may potentially predispose to the development of small intestinal bacterial overgrowth (SIBO), but this association is controversial due to conflicting results from studies conducted to date. The aim of this meta-analysis was to evaluate the association between the use of PPIs and the risk of SIBO. We systematically searched the online PubMed, Embase, and Cochrane Library databases and Web of Science for relevant articles published up to November 2016. Two researchers identified and extracted data independent of each other. The pooled analysis was performed using the generic inverse-variance random-effects model. Subgroup and sensitivity analysis were conducted to assess the stability and heterogeneity of the pooled results. The risk of publication bias was evaluated by assessing for funnel plot asymmetry and by Egger's test and Begg's test. A total of 19 articles met the eligibility criteria for the meta-analysis, reporting on 7055 subjects. The pooled odds ratio (OR) showed a statistically significant association between increased risk of SIBO and PPI use (OR 1.71, 95% confidence interval 1.20-2.43). Subgroup analyses demonstrated an association between SIBO and PPI use in studies that employed small bowel aspirates culture and glucose hydrogen breath tests (GHBT) as diagnostic tests for SIBO. Our meta-analysis suggests that the use of PPI moderately increases the risk of SIBO, thereby highlighting the need for appropriate prescribing of PPIs.

The role of gut microbiota in the modulation of drug action: a focus on some clinically significant issues

INTRODUCTION

A healthy gut microbiota is necessary for the normal operation of several body functions, including gastrointestinal sensitivity and motility, lipid and glucid metabolism, immune surveillance, and host behavior. In addition, intestinal bacteria contribute to determining the pharmacological properties of several drugs by producing different drug metabolizing enzymes. Areas covered: Four enzymatic processes are discussed: prodrug activation; drug inactivation; drug deconjugation; and hydrolysis of natural glycosides with further metabolism of released aglycones. For each of these processes, a literature search has been undertaken on certain paradigmatic examples that have significant clinical implications: aminosalicylates and anthranoid laxatives; digoxin; irinotecan and non-steroidal anti-inflammatory drugs (NSAIDs); rutin, diosmin, and baicalin. Expert commentary: The modulation of certain reactions catalyzed by gut bacterial enzymes may offer new opportunities to improve the clinical efficacy of drugs such as aminosalicylates, and natural glycosides by increasing their metabolic transformation, and of digoxin by reducing its inactivation, or to decrease the lower intestinal toxicity of irinotecan, and NSAIDs by inhibiting the hydrolytic cleavage of their conjugates. Randomized clinical trials are awaited to clarify whether new intervention strategies may modulate these processes and provide clinical benefits such as improved therapeutic outcomes and drug safety profiles.

Ketogal: A Derivative Ketorolac Molecule with Minor Ulcerogenic and Renal Toxicity

Ketorolac is a powerful non-steroidal anti-inflammatory drug (NSAID), with a great analgesic activity, present on the Italian market since 1991. Despite the excellent therapeutic activity, the chronic use of ketorolac has long been limited owing to the high incidence of gastrointestinal and kidney side events. In our previous study, we demonstrated that ketorolac-galactose conjugate (ketogal), synthesized and tested in a single-dose study, was able to reduce ulcerogenicity, while preserving the high pharmacological efficacy of its parent drug. In this paper, in order to verify the suitability of this compound, for repeated administration, ex vivo experiments on naïve mice were performed. Mice were treated for 5 or 7 days with the highest doses of two drugs (ketorolac 10 mg/kg and ketogal 16.3 mg/kg), and the expression of both gastric COX-1 and PGsyn was evaluated. Results showed that oral ketorolac treatment significantly reduced both enzymes; surprisingly, oral treatment with ketogal did not produce significant variation in the expression of the two constitutive enzymes. Moreover, histological experiments on stomach and kidneys clearly indicated that repeated administration of ketogal induced lower toxicity than ketorolac. At same time, in vivo results clearly showed that both ketorolac and ketogal had a similar therapeutic activity in a model of inflammation and in pain perception. These effects were accompanied by the reduction of enzyme expression such as COX-2 and iNOS, and by the modulation of levels of nuclear NF-κB and cytosolic IκB-α in the inflamed paws. These very encouraging results demonstrate for the first time that ketogal could represent a valid and novel therapeutic alternative to the ketorolac and might pave the way for clinical studies.