Drug-induced injury in the gastrointestinal tract: clinical and pathologic considerations

Assessing real-world safety concerns of Sacituzumab govitecan: a disproportionality analysis using spontaneous reports in the FDA adverse event reporting system

Aim

The aim of this study was to identify potential safety concerns associated with Sacituzumab Govitecan (SG), an antibody-drug conjugate targeting trophoblastic cell-surface antigen-2, by analyzing real-world safety data from the largest publicly available worldwide pharmacovigilance database.

Methods

All data obtained from the FDA Adverse Event Reporting System (FAERS) database from the second quarter of 2020 to the fourth quarter of 2022 underwent disproportionality analysis and Bayesian analysis to detect and assess the adverse event signals of SG, considering statistical significance when the lower limit of the 95% CI >1, based on at least 3 reports.

Results

Total of 1072 cases were included. The main safety signals were blood and lymphatic system disorders [ROR(95CI)=7.23 (6.43-8.14)], gastrointestinal disorders [ROR(95CI)=2.01 (1.81-2.22)], and relative infection adverse events, such as neutropenic sepsis [ROR(95CI)=46.02 (27.15-77.99)] and neutropenic colitis [ROR(95CI)=188.02 (120.09-294.37)]. We also noted unexpected serious safety signals, including large intestine perforation [ROR(95CI)=10.77 (3.47-33.45)] and hepatic failure [ROR(95CI)=3.87 (1.45-10.31)], as well as a high signal for pneumonitis [ROR(95CI)=9.93 (5.75-17.12)]. Additionally, age sub-group analysis revealed that geriatric patients (>65 years old) were at an increased risk of neutropenic colitis [ROR(95CI)=282.05 (116.36-683.66)], neutropenic sepsis [ROR(95CI)=101.11 (41.83-244.43)], acute kidney injury [ROR(95CI)=3.29 (1.36-7.94)], and atrial fibrillation [ROR(95CI)=6.91 (2.86-16.69)].

Conclusion

This study provides crucial real-world safety data on SG, complementing existing clinical trial information. Practitioners should identify contributing factors, employ monitoring and intervention strategies, and focus on adverse events like neutropenic sepsis, large intestine perforation, and hepatic failure. Further prospective studies are needed to address these safety concerns for a comprehensive understanding and effective management of associated risks.

Lactiplantibacillus plantarum Strain FLPL05 Promotes Longevity in Mice by Improving Intestinal Barrier

This study aimed to evaluate the effect of oral administration of probiotic Lactiplantibacillus plantarum FLPL05 on the lifespan and intestinal barrier of aged mice. L. plantarum FLPL05 significantly prolonged the lifespan of naturally aged mice, maintained the integrity of intestinal mucosal barrier, and reduced the inflammation level. The analysis of intestinal microbiota revealed that L. plantarum FLPL05 increased the relative abundance of Firmicutes and decreased the abundance of Bacteroides, accompanied by the increased proportions of Lactobacillus and Desulfovibrio in intestinal microbiota as well as the reduced proportions of Roseburia and Parabacteroides. The intestinal proteomics revealed that the oral administration of L. plantarum FLPL05 significantly upregulated the tight junction and simultaneously inhibited the expression of apoptotic-related proteins. The immunohistochemistry results also indicated that L. plantarum FLPL05 promoted the expression of tight junction proteins (ZO-1 and occludin) and reduced the apoptosis of intestinal cells. In addition, L. plantarum FLPL05 and the fermented supernatant increased the activity of HT-29. L. plantarum FLPL05 prolonged the lifespan by improving the health of the intestinal tract after aging and may be a potential probiotic and nutritional supplement for the elderly people.

Zinc and L-carnitine combination with or without methotrexate prevents intestinal toxicity during arthritis treatment via Nrf2/Sirt1/Foxo3 pathways: an In vivo and molecular docking approach

Methotrexate (MTX) is an antifolate that is inescapable and widely used to treat autoimmune diseases and is the gold standard medicine for the arthritic condition. Despite its importance, it is more prone to gastrointestinal toxicity, which is most common in arthritis patients during MTX treatment. Combination therapies are required to ensure MTX's antiarthritic activity while providing gastrointestinal protection. Zinc (Zn) and L-carnitine (Lc) are well-known potent antioxidants and anti-inflammatory supplements with promising results in pre-clinical studies. Arthritis was induced in Wistar rat's ankles with Freund's adjuvant and treated with either MTX (2.5 mg/kg b.w per week for two weeks) or Zn (18 mg/kg b.w. per day) Lc (200 mg/kg b.w. per day) individually or in combination (MTX + Zn Lc). The antiarthritic effects were evaluated by body weight, paw volume, ankle tissue, and joint histopathology. At the same time, anti-toxicity/gastrointestinal protective activity was examined by tissue oxidative stress markers, antioxidants, mitochondrial function, inflammatory mediators, and antioxidant signaling proteins and their binding mechanism. Repercussions of MTX intoxication induced upregulation of oxidative stress markers, antioxidant depletion, ATP depletion, decreased expression of Nrf2/Sirt1/Foxo3, and the overexpression of inflammatory mediators attenuated by co-treatment with Zn Lc. Zn Lc markedly mitigated MTX-instigated intestinal injury by activating antioxidant signaling mechanisms Nrf2/Sirt1/Foxo3 signaling and tissue architectural anomalies and exhibited an enhanced antiarthritic effect. In conclusion, we report that Zn Lc and MTX combination could presumably protect the intestine from low-dose MTX which managed arthritis but induced severe intestinal damage with increased inflammation and downregulated Nrf2/Sirt1/Foxo3 pathway.

Unusual Ileocecal Ulcers after Liver Transplantation for Hepatitis B Cirrhosis and Hepatocellular Carcinoma

We presented a case demonstrating ileocecal ulcers after liver transplantation for hepatitis B cirrhosis and hepatocellular carcinoma. The patient presented 4 years post-transplant with paroxysmal right lower abdominal pain. Due to a mild increase in the leukocyte and neutrophil count, infectious diseases were initially suspected. However, probiotic treatment did not help improve the symptom. An enhanced CT scan revealed a thickening in the ileocecal region, and endoscopy later showed multiple giant and deep ulcers in the ileocecal region with polypoid hyperplasia. Histopathology of an ulcer biopsy displayed benign ulcers, and chronic inflammation with non-caseous granulomas, without signs of a fungus or parasite infection. Epithelial exfoliation with atypical hyperplasia was observed, and a tacrolimus-induced ileocecal ulcer was considered by a pathologist. Clinical manifestation, lab findings, radiology, and pathology characteristics of ulcers were not consistent with the pathogenesis of ischemia, tuberculosis, CMV, EBV, tumor, or inflammatory bowel diseases. Abdominal pain was gradually relieved and subsided with the discontinuation of tacrolimus and corticosteroid administration.

Inhibitory Activity of Bioactive Phloroglucinols from the Rhizomes of Dryopteris crassirhizoma on Escherichia coli β-Glucuronidase: Kinetic Analysis and Molecular Docking Studies

Phloroglucinols-one of the major secondary metabolites in Dryopteris crassirhizoma-exhibit various pharmacological effects, such as antiviral, antioxidant, and antidiabetic activities. This study evaluated 30 phloroglucinols isolated from the rhizomes of D. crassirhizoma for their inhibitory activity on β-glucuronidase via in vitro assays. Among them, dimeric phloroglucinols 13-15 moderately inhibited β-glucuronidase, and trimeric phloroglucinols 26-28 showed strong inhibitory effects, with IC₅₀ values ranging from 5.6 to 8.0 μM. Enzyme kinetic analysis confirmed all six active compounds to be in a competitive mode of inhibition. Molecular docking simulations revealed the key binding interactions with the active site of β-glucuronidase protein and the binding mechanisms of these active metabolites. Our results suggest that the rhizomes of D. crassirhizoma and trimeric compounds 26-28 may serve as potential candidates for discovering and developing new β-glucuronidase inhibitors.

Gut inflammation induced by drugs: Can pathology help to differentiate from inflammatory bowel disease?

Drug‐induced mucosal injury (DIMI) in the gastrointestinal tract is important to recognise, partly because cessation of the culprit agent alone may result in resolution of symptoms. An ever‐growing list of medications, including newer immunotherapeutic agents and targeted therapies, can cause gastrointestinal inflammation of varying severity. However, the diagnosis of DIMI is challenging, as a single drug can induce a variety of histopathological patterns of injury including acute colitis, chronic colitis, microscopic colitis, apoptotic colopathy, and ischaemic‐type colitis. An additional consideration is the potential clinical, endoscopic and histological overlap of DIMI with gastrointestinal mucosal injury secondary to other entities such as inflammatory bowel disease (IBD). We discuss DIMI of the gastrointestinal tract with an emphasis on histological patterns that mimic IBD, histological features which may distinguish the two entities, and the diagnostic role and limitations of the pathologist.

The interplay between anticancer challenges and the microbial communities from the gut

Cancer being an increasing burden on human health, the use of anticancer drugs has risen over the last decades. The physiological effects of these drugs are not only perceived by the host's cells but also by the microbial cells it harbors as commensals, notably the gut microbiota. Since the early '50 s, the cytotoxicity of anticancer chemotherapy was evaluated on bacteria revealing some antimicrobial activities that result in an established perturbation of the gut microbiota. This perturbation can affect the host's health through dysbiosis, which can lead to multiple complications, but has also been shown to have a direct effect on the treatment efficiency.We, therefore, conducted a review of literature focusing on this triangular relationship involving the microbial communities from the gut, the host's disease, and the anticancer treatment. We focused specifically on the antimicrobial effects of anticancer chemotherapy, their impact on mutagenesis in bacteria, and the perspectives of using bacteria-based tools to help in the diagnostic and treatment of cancer.

Human Organoids for Predictive Toxicology Research and Drug Development

Organoids are three-dimensional structures fabricated in vitro from pluripotent stem cells or adult tissue stem cells via a process of self-organization that results in the formation of organ-specific cell types. Human organoids are expected to mimic complex microenvironments and many of the in vivo physiological functions of relevant tissues, thus filling the translational gap between animals and humans and increasing our understanding of the mechanisms underlying disease and developmental processes. In the last decade, organoid research has attracted increasing attention in areas such as disease modeling, drug development, regenerative medicine, toxicology research, and personalized medicine. In particular, in the field of toxicology, where there are various traditional models, human organoids are expected to blaze a new path in future research by overcoming the current limitations, such as those related to differences in drug responses among species. Here, we discuss the potential usefulness, limitations, and future prospects of human liver, heart, kidney, gut, and brain organoids from the viewpoints of predictive toxicology research and drug development, providing cutting edge information on their fabrication methods and functional characteristics.

Microbiota-Host-Irinotecan Axis: A New Insight Toward Irinotecan Chemotherapy

Irinotecan (CPT11) and its active metabolite ethyl-10-hydroxy-camptothecin (SN38) are broad-spectrum cytotoxic anticancer agents. Both cause cell death in rapidly dividing cells (e.g., cancer cells, epithelial cells, hematopoietic cells) and commensal bacteria. Therefore, CPT11 can induce a series of toxic side-effects, of which the most conspicuous is gastrointestinal toxicity (nausea, vomiting, diarrhea). Studies have shown that the gut microbiota modulates the host response to chemotherapeutic drugs. Targeting the gut microbiota influences the efficacy and toxicity of CPT11 chemotherapy through three key mechanisms: microbial ecocline, catalysis of microbial enzymes, and immunoregulation. This review summarizes and explores how the gut microbiota participates in CPT11 metabolism and mediates host immune dynamics to affect the toxicity and efficacy of CPT11 chemotherapy, thus introducing a new concept that is called "microbiota-host-irinotecan axis". Also, we emphasize the utilization of bacterial β-glucuronidase-specific inhibitor, dietary interventions, probiotics and strain-engineered interventions as emergent microbiota-targeting strategies for the purpose of improving CPT11 chemotherapy efficiency and alleviating toxicity.

L-citrulline: A preclinical safety biomarker for the small intestine in rats and dogs in repeat dose toxicity studies

INTRODUCTION

Gastrointestinal (GI) toxicity is still an issue within drug development, especially for novel oncology drugs. The identification of GI mucosal damage at an early stage with high sensitivity and specificity across preclinical species and humans remains difficult. To date, in preclinical studies, no qualified mechanistic, diagnostic or prognostic biomarkers exist for GI mucosal toxicity. L-citrulline is one of the most promising biomarker candidates used in clinical settings to quantify enterocyte integrity in various small intestinal diseases. L-citrulline is an intermediate metabolic amino acid produced mainly by functional enterocytes of the small intestine, whereby enterocyte loss will cause a drop in circulating L-citrulline.

METHODS

In several repeat-dose toxicity studies, plasma L-citrulline has been evaluated as a potential safety biomarker for intestinal toxicity in beagle dogs and Wistar (Han) rats treated with different oncological drug candidates in drug development. Clinical observations and body weight determinations were performed during the pretreatment, treatment and treatment-free recovery period as well as toxicokinetic, gross and histopathology examinations. The quantitative determination of plasma L-citrulline levels during the pretreatment (only dogs), treatment and treatment-free recovery period were performed using an HPLC MS/MS assay. In cynomolgus monkeys, the first investigations on baseline L-citrulline levels were performed.

RESULTS

In dogs, a dose- and exposure-dependent decrease of up to 50% in plasma L-citrulline was seen without histopathological alterations. However, a decrease of more than 50% in comparison to the individual animal pretreatment value of L-citrulline correlated very well with histopathological findings (intestinal crypt necrosis, villus atrophy, enterocyte loss) and clinical signs (bloody faeces and diarrhoea). During a treatment-free recovery period, a trend of increasing levels was observed in dogs. In rats, absolute L-citrulline plasma levels of treated animals decreased compared to the values of the concurrent control group. This decrease also correlated with the histopathological findings in the small intestine (single cell necrosis and mucosa atrophy). Because of a large physiological variation in L-citrulline plasma levels in dogs and rats, a clear cut-off value for absolute L-citrulline levels predictive of intestinal mucosal toxicity was difficult to establish. However, a > 50% decrease in L-citrulline plasma levels during the treatment period strongly correlated with histopathological findings.

DISCUSSION

Based on the performed analysis, a longitudinal investigation of L-citrulline plasma levels for individual animals in the control and treatment groups is essential and pretreatment values of L-citrulline levels in rodents would be highly informative. Overall, further cross-species comparison (Cynomolgus monkey, mouse) and implementation in clinical trials as exploratory biomarker is essential to foster the hypothesis and to understand completely the clinical relevance of L-citrulline as a small intestine biomarker.

l-citrulline: A preclinical safety biomarker for the small intestine in rats and dogs in repeat dose toxicity studies

INTRODUCTION

Gastrointestinal (GI) toxicity is still an issue within drug development, especially for novel oncology drugs. The identification of GI mucosal damage at an early stage with high sensitivity and specificity across preclinical species and humans remains difficult. To date, in preclinical studies, no qualified mechanistic, diagnostic or prognostic biomarkers exist for GI mucosal toxicity. l-citrulline is one of the most promising biomarker candidates used in clinical settings to quantify enterocyte integrity in various small intestinal diseases. l-citrulline is an intermediate metabolic amino acid produced mainly by functional enterocytes of the small intestine, whereby enterocyte loss will cause a drop in circulating l-citrulline.

METHODS

In several repeat-dose toxicity studies, plasma l-citrulline has been evaluated as a potential safety biomarker for intestinal toxicity in beagle dogs and Wistar (Han) rats treated with different oncological drug candidates in drug development. Clinical observations and body weight determinations were performed during the pretreatment, treatment and treatment-free recovery period as well as toxicokinetic, gross and histopathology examinations. The quantitative determination of plasma l-citrulline levels during the pretreatment (only dogs), treatment and treatment-free recovery period were performed using an HPLC MS/MS assay. In cynomolgus monkeys, the first investigations on baseline l-citrulline levels were performed.

RESULTS

In dogs, a dose- and exposure-dependent decrease of up to 50% in plasma l-citrulline was seen without histopathological alterations. However, a decrease of more than 50% in comparison to the individual animal pretreatment value of l-citrulline correlated very well with histopathological findings (intestinal crypt necrosis, villus atrophy, enterocyte loss) and clinical signs (bloody faeces and diarrhoea). During a treatment-free recovery period, a trend of increasing levels was observed in dogs. In rats, absolute l-citrulline plasma levels of treated animals decreased compared to the values of the concurrent control group. This decrease also correlated with the histopathological findings in the small intestine (single cell necrosis and mucosa atrophy). Because of a large physiological variation in l-citrulline plasma levels in dogs and rats, a clear cut-off value for absolute l-citrulline levels predictive of intestinal mucosal toxicity was difficult to establish. However, a > 50% decrease in l-citrulline plasma levels during the treatment period strongly correlated with histopathological findings.

DISCUSSION

Based on the performed analysis, a longitudinal investigation of l-citrulline plasma levels for individual animals in the control and treatment groups is essential and pretreatment values of l-citrulline levels in rodents would be highly informative. Overall, further cross-species comparison (Cynomolgus monkey, mouse) and implementation in clinical trials as exploratory biomarker is essential to foster the hypothesis and to understand completely the clinical relevance of l-citrulline as a small intestine biomarker.

A peptidoglycan storm caused by β-lactam antibiotic's action on host microbiota drives Candida albicans infection

The commensal fungus Candida albicans often causes life-threatening infections in patients who are immunocompromised with high mortality. A prominent but poorly understood risk factor for the C. albicans commensal‒pathogen transition is the use of broad-spectrum antibiotics. Here, we report that β-lactam antibiotics cause bacteria to release significant quantities of peptidoglycan fragments that potently induce the invasive hyphal growth of C. albicans. We identify several active peptidoglycan subunits, including tracheal cytotoxin, a molecule produced by many Gram-negative bacteria, and fragments purified from the cell wall of Gram-positive Staphylococcus aureus. Feeding mice with β-lactam antibiotics causes a peptidoglycan storm that transforms the gut from a niche usually restraining C. albicans in the commensal state to promoting invasive growth, leading to systemic dissemination. Our findings reveal a mechanism underlying a significant risk factor for C. albicans infection, which could inform clinicians regarding future antibiotic selection to minimize this deadly disease incidence.

A reactive oxygen species-responsive antioxidant nanotherapy for the treatment of drug-induced tissue and organ injury

Drug-induced tissue injury has become a growing public health problem. Gastrointestinal injury and liver dysfunction are the most common side effects related to drug therapies, resulting in high morbidity and mortality in recent years. The overproduction of reactive oxygen species (ROS) is critically involved in the pathogenesis of drug-induced tissue injury. Consequently, antioxidant therapy represents a very promising strategy for the treatment of drug-induced tissue injury. Herein, a multifunctional antioxidant nanotherapy (TON) is engineered from a cyclodextrin-derived ROS-responsive material and a radical scavenger tempol, and is capable of eliminating a broad spectrum of ROS. After oral administration, TON can passively accumulate in the inflamed gastrointestinal tissues in mice with indomethacin-induced gastrointestinal injury. Correspondingly, TON shows superior efficacy in two representative murine models of indomethacin-induced gastrointestinal injury and acetaminophen-induced hepatic injury via attenuating oxidative stress and mitigating inflammatory responses. Additionally, preliminary in vitro and in vivo experiments demonstrate the good safety profile of TON. Consequently, the ROS-responsive antioxidant nanotherapy TON is promising for the treatment of drug-induced tissue and organ injury.

Montmorillonite-Enveloped Zeolitic Imidazolate Framework as a Nourishing Oral Nano-Platform for Gastrointestinal Drug Delivery

Oral administration of medicine faces physiological constraints imposed by the gastrointestinal tract (GIT) and simultaneously causes irritation to GI mucosa, which motivates us to pursue the innovation of a GI drug delivery system. Inspired by the mucosa-nutrient functions of Zinc element and smectite clay, a montmorillonite (MMT)-enveloped zeolitic imidazolate framework (M-ZIF-8) is developed in a successive one-pot fabrication of ZIF-8 encapsulated medicine, and followed MMT coating to yield a core-shell nanoplatform for GI drug delivery. ZIF-8 encapsulated medicines can maintain their intrinsic structure, and MMT layer potentiates mucous-adhesion and optimizes medicine release. Validated in gastritis and colitis models, M-ZIF-8 not only achieves efficient GI delivery of nonsteroidal anti-inflammatory drugs (NSAIDs) for inflammation inhibition, but also reduces the NSAIDs-induced GI irritation, promoting mucosal healing in GIT. Coupled with the facile construction and biocompatibility, M-ZIF-8 shows a significant advancement in GI drug delivery.

Clopidogrel-induced Pill Oesophagitis

Antiplatelet agents are routinely given to prevent thrombosis of coronary stents. Often this occurs during or immediately after the procedure, while the patient is still on the catheterisation laboratory table. Ingestion of pills while supine sometimes causes mild dysphagia and discomfort but, rarely, it can cause a more severe complication. We report a case of clopidogrel ingested during PCI, which caused chest pain and pill oesophagitis after the procedure. Conservative treatment was effective, symptoms resolved, and follow-up endoscopy showed resolution of the oesophageal inflammation.

Combination Compositions Composed of l-Glutamine and Si-Jun-Zi-Tang Might Be a Preferable Choice for 5-Fluorouracil-Induced Intestinal Mucositis: An Exploration in a Mouse Model

Intestinal mucositis is a common toxicity of many anti-neoplastic therapies that negatively influences health, the quality of life, economic outcomes, and even the success of cancer treatment. Unfortunately, there is presently no optimal medicine that is able to effectively manage this condition. l-glutamine is one of the most frequently used agent in practice among the limited treatment choices due to its safety and inexpensiveness despite there being a lack of evidence. Previous studies indicated that l-glutamine may alleviate mucositis and mucosal atrophy but failed to improve patients' macroscopic conditions, such as the occurrence of diarrhea. A compound glutamine capsule (G-SJZ), composed of l-glutamine and the traditional Chinese herbal formula Si-Jun-Zi-Tang, has been used in China for 23 years to treat many types of gastrointestinal diseases, including gastrointestinal reactions induced by radiotherapy and chemotherapy. However, the exact effect of G-SJZ on intestinal mucositis is unclear, and moreover, whether l-glutamine combined with Si-Jun-Zi-Tang is more effective than l-glutamine alone have not been studied. In the current study, we explored the effects of G-SJZ and l-glutamine in a mouse model of intestinal mucositis induced by 5-fluorouracil (5-Fu). The results revealed that pretreatment with G-SJZ ameliorated the physical manifestations of weight loss and the severity of diarrhea following continuous 5-Fu injections in mice. Likewise, the histopathological damage and the destruction of villus and crypt structures in the intestinal mucosa as well as the increase in circulating intestinal injury markers caused by 5-Fu were reversed with G-SJZ pretreatment. Furthermore, the protective effect of G-SJZ was accompanied by modulations in the immunohistochemical expression of tight junction proteins. Interestingly, although treatment with a dose of l-glutamine alone that was equivalent to the dose in G-SJZ also showed a protective effect, it did not appear to be as strong as treatment with G-SJZ. Si-Jun-Zi-Tang in G-SJZ may compensate for the deficiencies of l-glutamine in this model which seems not to be related to the regulation of tight junction proteins. Our study is the first to suggest that the combined use of l-glutamine and Si-Jun-Zi-Tang might be more effective than l-glutamine alone despite exact mechanism still needs further study. Because of the limited number of therapeutic agents, G-SJZ is likely to be a preferable choice for intestinal mucositis.

A Citrulline-Based Translational Population System Toxicology Model for Gastrointestinal-Related Adverse Events Associated With Anticancer Treatments

Gastrointestinal (GI)-related adverse events (AEs) are commonly observed in the clinic during cancer treatments. Citrulline is a potentially translatable biomarker of GI AEs. In this study, irinotecan-induced citrulline changes were studied for a range of doses and schedules in rats. A translational system toxicology model for GI AEs using citrulline was then developed based on new experimental data and parameters from a literature intestinal cell dynamic model. With the addition of feedback-development and tolerance-development mechanisms, the model well captured the plasma citrulline profiles after irinotecan treatment in rats. Subsequently, the model was translated to humans and predicted the observed GI AE dynamics in humans including dose-scheduling effect using the cytotoxic and feedback parameters estimated in rats with slight calibrations. This translational toxicology model could be used for other antineoplastic drugs to simulate various clinical dosing scenarios before human studies and mitigate potential GI AEs.

Drug-Induced Small Bowel Injury: a Challenging and Often Forgotten Clinical Condition

PURPOSE OF REVIEW

Most drugs are given by the oral route. Oral intake allows direct contact between the drug and the entire GI tract mucosa, exposing it to potential topical damage until absorption. Medication-induced GI symptoms and lesions are therefore commonly encountered in clinical practice. This review will examine the most common drugs or classes of drugs affecting small bowel function and/or structure.

RECENT FINDINGS

Since non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used medicines, NSAID enteropathy is highly prevalent and brings about considerable morbidity. Antimicrobials and proton-pump inhibitors profoundly modify intestinal microbiota, affecting gut sensory and motor functions, while other drugs (like iron and gold derivatives) impair intestinal permeability. Olmesartan (and likely ACE inhibitors) induce villous atrophy and consequent malabsorption. Mycophenolate mofetil, cancer chemotherapeutic agents, and immune checkpoint inhibitors cause intestinal inflammation, abdominal pain, and diarrhea. Potassium chloride supplements may induce small bowel ulceration, stenosis, and perforation while the cotraceptive pill and anticoagulants are associated with intestinal ischemia and spontaneous intramural hematoma, respectively. In clinical practice, a deep knowledge of clinical pharmacology and toxicology and a high degree of suspicion of drug-related adverse events are mandatory. Only then, the practicing physician will be able to diagnose medication-induced small bowel lesions correctly and will implement the best strategies to treat them.

The isolated caecal patch lesion: a clinical, endoscopic and histopathological study

Objective

To describe and investigate the potential causes of the isolated caecal patch lesion, a previously undescribed endoscopic phenomenon of a lesion fulfilling endoscopic and histopathological criteria for chronic inflammatory bowel disease but without evidence of similar inflammatory pathology elsewhere at colonoscopy.

Methods

Cases were collected prospectively by one specialist gastrointestinal pathologist over a 10-year period. Full endoscopic and histopathological analysis was undertaken and follow-up sought to understand the likely cause(s) of the lesions.

Results

Six cases are described. Two had very close links with ulcerative colitis, one predating the onset of classical distal disease and the other occurring after previous demonstration of classical distal ulcerative colitis. Two occurred in younger patients and we postulate that these lesions may predict the subsequent onset of chronic inflammatory bowel disease. Finally two can be reasonably attributed to the effects of non-steroidal inflammatory agent therapy.

Conclusions

Caecal patch lesions can be demonstrated in isolation. Despite the strong association of caecal patch lesions with ulcerative colitis, solitary lesions may well have disparate causes but nevertheless possess a close relationship with chronic inflammatory bowel disease.

Phenotype of histologically suspected drug-induced colitis; results of a comparative, retrospective cohort study

Background/aims: Drug-induced colitis (DiC) is a rarely reported form of colonopathy and data about the clinical and endoscopic characteristics are scarce. The aim was to investigate the phenotype of DiC. Methods: Patients in a retrospective case control study were assigned to either DiC or one of two age- and gender-matched control groups (non-inflammatory controls and inflammatory colitis from other causes) based on histopathological findings. Patients' basic characteristics, symptoms, biochemical results and endoscopic appearance were collected. Statistical analysis included ANOVA, the chi-squared test and two-tailed t-test. Results: A total of 211 patients with DiC were included (97 males, age 62.1 ± 16.1 years, BMI 25.9 ± 6.1 kg m^-2). In comparison to both control groups, DiC patients presented higher ASA and ECOG-scores and more particularly atherosclerotic comorbidities. The most abundant symptoms were abdominal pain (51.8%), diarrhoea (50.7%) and haematochezia (24.3%). The red blood cell count demarcated anaemia (12.7 ± 2.3 mg/dl) and C-reactive protein was slightly elevated (2.7 ± 5.2 mg/dl). The endoscopic features included erythema (46.9%), oedema (29.9%), erosions (29.9%) and ulcers (14.7%). The inflammation affected the rectum rarely (2.4%) but affected the rest of the colon without predilection in a segmental manner (p<.05). The severity of DiC was mostly mild (85.7%). Conclusions: The phenotype of DiC differs slightly from that of colitis from other causes. Taking the clinical features into account might help to confirm drug-induced aetiology once the pathologist has raised the suspicion.

Triggers of histologically suspected drug-induced colitis

BACKGROUND

Drug toxicity is a common and even serious problem in the gastrointestinal tract that is thought to be caused by a broad spectrum of agents. Although withdrawal of the causative agent would cure the disease knowledge is scarce and mostly derives from case reports and series.

AIM

To investigate potential triggers of drug-induced colitis (DiC).

METHODS

We conducted a retrospective, observational case control study. Patients were assigned to DiC or one of two age- and gender-matched control groups (non-inflammatory controls and inflammatory colitis of another cause) based on histopathological findings. Histopathology was reassessed in a subset of patients (28 DiC with atherosclerosis, DiC without atherosclerosis and ischaemic colitis each) for validation purposes. Medical history was collected from the electronic database and patient records. Statistical analysis included chi-squared test, t-test, logistic and multivariate regression models.

RESULTS

Drug-induced colitis was detected in 211 endoscopically sampled biopsy specimens of the colon mucosa (7% of all screened colonoscopic biopsy samples); a total of 633 patients were included equally matched throughout the three groups (291 males, mean age: 62.1 ± 16.1 years). In the univariate analysis, DiC was associated with diuretics, dihydropyridines, glycosides, ASS, platelet aggregation inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), statins and fibrates, and with atherosclerosis, particularly coronary heart disease, and hyperlipoproteinaemia. Echocardiographic parameters did not show substantial differences. In the multivariate analysis only fibrates [odds ratio (OR) = 9.1], NSAIDs (OR = 6.7) and atherosclerosis (OR = 2.1) proved to be associated with DiC. Both DiC reassessment groups presented milder inflammation than ischaemic colitis. The DiC patients with atherosclerosis exhibited histological features from both DiC without atherosclerosis and ischaemic colitis.

CONCLUSION

Several drugs indicated for the treatment of cardiovascular and related diseases are associated with DiC. Atherosclerosis and microcirculatory disturbances seem to play an important pathogenetic role.

Hydrogen Sulfide Releasing 2-Mercaptoacrylic Acid-Based Derivative Possesses Cytoprotective Activity in a Small Intestine of Rats with Medication-Induced Enteropathy

Small intestinal injury is known to be one of the most commonly appearing pathologies, resulting in the use of medications such as: nonsteroidal anti-inflammatory drugs (NSAIDs), antitumor drugs and angiotensin-converting enzyme (ACE) inhibitors. The principal objective of this study is to evaluate the action of a novel mercaptoacrylic acid derivative able to release H₂S on parameters of NO-synthase system and oxidative stress. Inducing enteropathy, three types of medications were used: indomethacin, an NSAID (35 mg/kg); methotrexate, an antitumor drug (10 mg/kg); and enalapril, an ACE inhibitor (2 mg/kg/day). 2-[(4-chlorophenyl-carbamoyl)-methyl]-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-acrylic acid (2C3DHTA) was introduced based on the background of medication-induced enteropathy (10 mg/kg/day). The survey showed that malondialdehyde (MDA) concentration, myeloperoxidase (MPO) activity, superoxide dismutase (SOD), catalase, and NO-synthases (NOS) were determined in the small intestinal mucosa. The increase in inducible NO-synthase (iNOS) activity was due to indomethacin and methotrexate administration. Constitutive NO-synthase (cNOS) activity was decreased by an ACE-inhibitor. The cytoprotective effect was demonstrated by 2C3DHTA, which returned iNOS activity to its control level and increased cNOS activity. The enterotoxic action of studied medication was accompanied by the development of oxidative stress manifested, activity of MPO was increased. MPO activity and manifestations of oxidative stress were decreased by 2C3DHTA. Effects of 2C3DHTA can be explained by the action of H₂S, released from this compound in the gastrointestinal (GI) system.

Spectrum of Drug-induced Chronic Diarrhea

The evaluation of a patient with chronic diarrhea can be quite frustrating, as it is expensive and involves multiple diagnostic studies. Moreover, identification of a drug as a cause of chronic diarrhea is a challenge in patients taking multiple medications. The disease may either be associated with intestinal mucosal changes, mimicking diseases such as celiac disease, or purely functional, with no histopathologic change. Drug-induced diarrhea may or may not be associated with malabsorption of nutrients, and a clinical improvement may occur within days of discontinuation of the drug, or may take longer when associated with mucosal injury. Diarrhea in diabetics, often attributed to poor management and lack of control, may be due to oral hypoglycaemic agents. Chemotherapy can result in diffuse or segmental colitis, whereas olmesartan and a few other medications infrequently induce a disease that mimics celiac disease, but is not associated with gluten intolerance. In short, increased awareness of a drug, as a cause for diarrhea and a clear understanding of the clinical manifestations will help clinicians to solve this challenging problem. This article aims to review drug-induced diarrhea to (a) understand known pathophysiological mechanisms; (b) assess the risk associated with frequently prescribed medications, and discuss the pathogenesis; and

Oral drug therapy in elderly with dysphagia: between a rock and a hard place!

Demographic indicators forecast that by 2050, the elderly will account for about one-third of the global population. Geriatric patients require a large number of medicines, and in most cases, these products are administered as solid oral solid dosage forms, as they are by far the most common formulations on the market. However, this population tends to suffer difficulties with swallowing. Caregivers in hospital geriatric units routinely compound in solid oral dosage forms for dysphagic patients by crushing the tablets or opening the capsules to facilitate administration. The manipulation of a tablet or a capsule, if not clearly indicated in the product labeling, is an off-label use of the medicine, and must be supported by documented scientific evidence and requires the patient's informed consent. Compounding of marketed products has been recognized as being responsible for an increased number of adverse events and medical errors. Since extemporaneous compounding is the rule and not the exception in geriatrics departments, the seriousness and scope of issues caused by this daily practice are probably underestimated. In this article, the potential problems associated with the manipulation of authorized solid oral dosage forms are discussed.

Helicobacter-negative gastritis: a distinct entity unrelated to Helicobacter pylori infection

BACKGROUND

Helicobacter-negative gastritis is diagnosed when no organisms are detected in a gastric mucosa with typical features of Helicobacter gastritis (Hp-gastritis). If Helicobacter-negative gastritis consisted mostly of 'missed' Helicobacter infections, its prevalence should represent a constant percentage of these infections in a population, and their clinico-epidemiological features would overlap.

AIM

To compare the epidemiologic patterns of Hp-positive and Hp-negative gastritis.

METHODS

From a pathology database, we extracted demographic, clinical and histopathological data from patients with gastric biopsies (1.2008-12.2013). We allocated patients to high (≥12%) and low (≤6%) H. pylori prevalence regions defined by ZIP code-based data. The prevalence of H. pylori-positive and -negative gastritis by sex, age and state were expressed as a per cent of the total study population stratified accordingly.

RESULTS

Of 895 323 patients, 10.6% had Hp-gastritis and 1.5% Helicobacter-negative gastritis. Hp-gastritis, but not Helicobacter-negative gastritis, was more common in males than females (OR 1.17, 95% CI: 1.16-1.19). While Hp-gastritis was more prevalent in high than in low-prevalence areas (OR 3.65, 95% CI: 3.57-3.74), Helicobacter-negative gastritis was only minimally affected by the underlying H. pylori prevalence (1.7% vs. 1.5%). The age-specific prevalence of Hp-gastritis peaked in the 4th to 5th decades; Helicobacter-negative gastritis exhibited a low and relatively flat pattern. The geographic distribution of H. pylori-positive and -negative gastritis showed no significant correlation. Intestinal metaplasia was found in 13.0% of patients with Hp-gastritis and in 6.1% of those with Helicobacter-negative gastritis (OR 0.43, 95% CI: 0.40-0.47).

CONCLUSION

These data suggest that Helicobacter-negative gastritis is, in the vast majority of cases, a nosologically and epidemiologically distinct entity that deserves further investigation.

Activation of the farnesoid-X receptor protects against gastrointestinal injury caused by non-steroidal anti-inflammatory drugs in mice

BACKGROUND AND PURPOSE

Low doses of acetyl salicylic acid (ASA) and non-steroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal damage. The farnesoid X receptor (FXR) is a bile acid sensor essential for maintenance of intestinal homeostasis. Here, we have investigated whether FXR is required for mucosal protection in models of gastrointestinal injury caused by ASA and NSAIDs and if FXR activation has potential in the treatment or prevention of gastrointestinal injury caused by these agents.

EXPERIMENTAL APPROACH

FXR(+/+) and FXR(-/-) mice were given ASA (10 to 100 mg·kg(-1) ) or NSAIDs. Gastric and intestinal mucosal damage assessed by measuring lesion scores. FXR were activated by giving mice natural (chenodeoxycholic acid; CDCA) or synthetic (GW4064) FXR agonists.

KEY RESULTS

FXR, mRNA and protein, was detected in human and mouse stomach. FXR(-/-) mice were more prone to develop severe gastric and intestinal injury in response to ASA and NSAIDs and showed a severe reduction in the gastrointestinal expression of cystathionine-γ-lyase (CSE), an enzyme required for generation of hydrogen sulphide. CSE expression was reduced by ≈50% in wild-type mice challenged with ASA. Treating wild-type mice but not FXR(-/-) mice with CDCA or GW4064 protected against gastric injury caused by ASA and NSAIDs, by a CSE-dependent and cycloxygenase- and NO-independent, mechanism. FXR activation by GW4064 rescued mice from intestinal injury caused by naproxen.

CONCLUSIONS AND IMPLICATIONS

FXR was essential to maintain gastric and intestinal mucosal barriers. FXR agonists protected against gastric injury caused by ASA and NSAIDs by a CSE-mediated mechanism.

Histopathologic diagnosis of eosinophilic conditions in the gastrointestinal tract

Eosinophils, a constitutive component of the columnar-lined gastrointestinal tract, play an essential role in allergic responses and parasitic infections. The tissue density of these cells also increases in a variety of conditions of uncertain etiology. With the exception of the esophageal squamous epithelium, in which no eosinophils are normally present, the population of normal eosinophils in the remainder of the luminal gut is poorly defined. Therefore, histopathologists must rely on their subjective judgment to determine when a diagnosis of eosinophilic gastritis, enteritis, or colitis should be rendered. Eosinophilic esophagitis is currently the best defined and most studied eosinophilic condition of the digestive tract; therefore, the confidence in accurate diagnosis is increasing. In contrast, the characteristic clinicopathologic features of eosinophilic conditions affecting other parts of the digestive tract remain somewhat elusive. This review was designed to present pathologists with simple and practical information for the biopsy-based histopathologic diagnosis of eosinophilic esophagitis, gastritis, enteritis, and colitis. It was prepared by critically reviewing more than 200 articles on the topic, along with incorporating evidence accumulated through our own collective experience. We anticipate that by increasing pathologists' confidence in reporting these abnormal but often nameless eosinophilic infiltrates, we can help better define and characterize their significance.

Eosinophilic gastritis: histopathological characterization and quantification of the normal gastric eosinophil content

There is limited information about normal eosinophil counts in the gastric mucosa. The purpose of this study was to evaluate the histopathology of 60 patients whose biopsies showed increased eosinophils in the gastric mucosa. We also investigated the eosinophil content in gastric biopsies from normal controls (matched for age, sex, and zip code), from patients with Helicobacter pylori gastritis, and patients with Crohn's disease. Eosinophils were counted in five random high-power fields (HPFs) and reported in eosinophils/mm(2). Involvement of the muscularis mucosae or submucosa, sheets of eosinophils, and infiltration of the gastric epithelium were also evaluated. The median eosinophil count in the study patients was 539 eosinophils/mm(2); mean±SD=653±418 eosinophils/mm(2); range 127-2108. Sheets of eosinophils were seen in 38 patients, 27 showed involvement of the muscularis mucosae or submucosa. There were 7 patients without epithelial infiltration by eosinophils, whereas 34 were tallied as rare and 19 were scored as abundant. No study patient had no evidence of H. pylori. The mean eosinophil count for the 135 normal controls was 15.5±16.8 SD eosinophils/mm(2) (range 0-110); in the 93 controls with H. pylori gastritis the mean eosinophil count was 25±32.6 SD eosinophils/mm(2) (range 0-219); and for the 53 controls with Crohn's disease it was 31.4±44.4 SD eosinophils/mm(2) (range 0-203). There were no significant differences between the counts in biopsies from the antrum and corpus, and no significant variations by age, geographic location, or season. This study confirms that, in the United States population, the normal gastric eosinophilic counts are usually <38 eosinophils/mm(2). We recommend 'histological eosinophilic gastritis' for the diagnosis of gastric biopsies that show an average density ≥127 eosinophils/mm(2) (or ≥30 eosinophils per HPF) in at least five HPFs in the absence of known associated causes of eosinophilia.

Do non-steroidal anti-inflammatory drugs cause exacerbations of inflammatory bowel disease?

The safety of non-steroidal anti-inflammatory drugs (NSAIDs) in patients with inflammatory bowel disease (IBD) remains unclear. This report discusses potential mechanisms whereby NSAIDs might exacerbate IBD and reviews the available clinical data on the role of NSAIDs in causing exacerbations of ulcerative colitis (UC) and Crohn's disease (CD).

Long Term Use of Leflunomide as a Cause of Severe Diarrhea?

Leflunomide is a recently developed disease modifying antirheumatic drug that may cause acute diarrhea as an adverse effect. This adverse effect is usually mild and develops during the first few weeks of treatment. In this report, we present a case of rheumatoid arthritis patient with severe diarrhea treated with leflunomide for an extended period of time. (Turk J Rheumatol 2010; 25: 41-3)

Lymphocytic disorders of the gastrointestinal tract: a review for the practicing pathologist

Increased numbers of intraepithelial lymphocytes (lymphocytosis) can be found in the esophagus, stomach, small intestine, and colon in a variety of clinical circumstances. This review, directed at practicing pathologists, portrays the normal resident lymphocyte population in the mucosa of each segment of the digestive tract and discusses the different situations that may result in quantitative or qualitative alterations of intraepithelial lymphocytes. Esophageal lymphocytosis has not been fully characterized and its clinical significance, if any, awaits definition. Thus, this diagnosis is presently discouraged. In the stomach, it is particularly important to exclude Helicobacter pylori infection and celiac sprue before diagnosing lymphocytic gastritis. Duodenal lymphocytic infiltrates, inextricably tied with alterations of the villous architecture of the mucosa, are often caused by gluten sensitivity. However, similar morphologic changes may be caused by a vast array of other conditions that must be carefully considered and excluded. Lymphocytic and collagenous colitis are most often unexplained, but their frequent association with autoimmune conditions or certain medications deserve a thorough investigation in each case. Using a combination of histologic and clinical clues, a cause for the intraepithelial lymphocytic infiltration can be identified in many instances. As some of the associated conditions are amenable to effective treatment, the importance of diligently seeking such associations before resorting to a diagnosis of primary lymphocytosis is emphasized.

Pharmacologic consideration of commonly used gastrointestinal drugs in the elderly

Gastrointestinal (GI) manifestations in older adults can be caused or alleviated by drug therapy. GI medications, such as proton pump inhibitors and histamine-2 receptor antagonists, are among the most commonly used medications in long-term care facilities in the United States. This article reviews the alterations in pharmacokinetic disposition of medications that occur with aging and highlights the pharmacology of commonly used GI drugs. Selected GI conditions that are drug induced and preventable are identified, and recommendations for GI drugs to be avoided in older adults are provided.

Gastrointestinal side effects of prescription medications in the older adult

Gastrointestinal (GI) symptoms resulting from either prescription medications or over-the-counter drugs are frequently encountered in geriatric practice but often mistaken for symptoms of an organic disease leading to multiple diagnostic studies. The morbidity, mortality, and medical costs associated with drug toxicity, even when restricted to the GI tract, are probably underestimated. The consequences of drug toxicity are quite variable and range from a symptom of mild discomfort (eg, drug-induced diarrhea) at one end of the spectrum, to fatal GI hemorrhage or perforation. Better awareness of the possibility of drug-induced GI tract pathology by primary care physicians improves the recognition of these adverse effects, and ultimately, improves patient care. This review focuses on the most common and well-described drug-related side effects of the GI tract.