Gut Toxicity Research Articles

Protective effect of neurotensin receptor-1 agonist PD 149163 against lipopolysaccharide-induced gut toxicity in mice

The interaction between neuroendocrine and immune components of the gut maintains the organism's physical and psychological health. Its disruption may reflect in disease conditions such as inflammatory bowel disease (IBD) and mental illness. The lipopolysaccharide (LPS) disrupts the endocrine-immune homeostasis resulting in gut toxicity. The Neurotensin receptor-1 (NTR-1) agonist PD 149163 (PD) acts as an atypical antipsychotic drug in psychiatric illness, but its role in modulating gut pathophysiology remains unknown. Therefore, the aim of the present study was to evaluate the protective effect of PD against LPS-induced gut toxicity. Swiss albino female mice (12 weeks) were divided into six groups (n = 6/group): (I) Control, (II) LPS (1 mg/kg, for 5 days), (III) LPS (1 mg/kg, for 5 days)+PD low (100 µg/kg, for 21 days), (IV) LPS (1 mg/kg, for 5 days)+PD high (300 µg/kg, for 21 days), (V) PD low (100 µg/kg, for 21 days), and (VI) PD high (300 µg/kg, for 21 days). Drugs were given intraperitoneal in the morning. PD administration prevented the LPS-induced gut inflammation observed in damage of epithelial barrier, disruption of goblet cells, and condensation of lamina propria (LP). The LPS-induced oxidative stress characterized by decreased superoxide dismutase (SOD) activity and increased lipid hydroperoxide (LOOH) (p < 0.001 for both), and enhanced interleukine-6 (IL-6) & tumor necrosis factor-α (TNF-α) (p < 0.001 for both) as well as immunointensity of NT (p < 0.01) and NTR-1 (p < 0.05) were reversed and normalized to control after PD treatment. Thus, the anti-inflammatory, anti-oxidative, and cell proliferation properties of PD modulate the gut toxicity in LPS-challenged mice.

Bone-Targeted Pharmacological Inhibition of Notch Signaling As a Novel Approach to Inhibit Myeloma Growth and Bone Destruction

Notch signaling between myeloma cells and cells of the bone marrow microenvironment favors growth and survival of myeloma cells and increases osteoclast formation. In vitro and in vivo studies demonstrated that systemic inhibition of Notch signaling using gamma-secretase inhibitors (GSIs) decreases myeloma cell growth and reduces osteoclast generation. However, the use of GSIs in the clinic is limited by the ocurrence of severe adverse side effects as fatigue, skin disorders, and acute gastrointestinal toxicity. To circumvent the side effects associated with systemic inhibition of Notch signaling using GSIs, we synthesized a novel Notch inhibitor by linking GSI-XII to an inactive bone-targeting molecule (BT). BT-GSI was designed to direct the conjugate to bone where the linker is cleaved under the acidic environment generated by osteoclast activity, thus locally releasing the GSI.In vitro, the control unconjugated GSI decreased Notch target gene expression (Hes1) in 5TGM1 myeloma cells, but BT-GSI had no effect. However, when both GSI and BT-GSI were pre-incubated at low pH to mimic the acidic conditions in resorption sites, equal inhibition of Notch target gene expression was observed. Ex vivo, both GSI and BT-GSI (non-pre-incubated) similarly decreased Hes1/5 expression in whole bone organ cultures that reproduce conditions present in the bone microenvironment. In vivo, administration of BT-GSI (5µg/g, 3xwk) to normal 4-month old female mice for 2 weeks was well tolerated and no skin issues were observed. Mice treated with BT-GSI exhibited decreased Hey2, Hes5, and Hes7 mRNA expression in whole bone preparations, but not in brain or gut, compared to vehicle-treated mice. Further, BT-GSI did not increase Apsidin expression in the gut, a biomarker of gastrointestinal toxicity. BT-GSI-treated mice exhibited decreased serum levels of CTX (-40%), a bone resorption marker, and upregulated Opg mRNA expression in bone, thereby decreasing the Rankl/Opg ratio. Consistent with these findings, BT-GSI-treated mice exhibited a 50% decreased in the bone surface covered by osteoclasts compared to vehicle-treated control mice. BT-GSI treated mice exhibited higher total (+3%), femoral (+4%), and spinal (+7%) BMD compared to control mice. Further, mice receiving BT-GSI had increased cancellous bone volume (+25%) and trabecular thickness (+10%) compared to vehicle-treated mice, as quantified by microCT. Serum levels of the bone formation marker P1NP, as well as bone formation and mineral apposition rates, number of osteoblasts, and the expression of osteoblast markers, including Wnt target genes and the osteocyte- derived Sost/Sclerostin remained unchanged in bones of BT-GSI-treated mice compared to control mice.Taken together, these findings demonstrate that BT-GSI induces bone specific Notch inhibition, reduces osteoclast formation without affecting osteoblast activity, favoring bone gain, and lacks gut toxicity. Thus, BT-GSI is a promising approach to inhibit the growth of myeloma cells and prevent bone loss in myeloma patients, while circumventing the deleterious side effects of this class of inhibitors in other tissues. DisclosuresDelgado-Calle:PharmaMar: Research Funding. Roodman:PharmaMar: Research Funding. Bellido:PharmaMar: Research Funding.

Mechanisms of Gegen Qinlian Pill to ameliorate irinotecan-induced diarrhea investigated by the combination of serum pharmacochemistry and network pharmacology

Ethnopharmacological relevanceTraditional Chinese medicine suggests the use of natural extracts and compounds is a promising strategy to prevent irinotecan (CPT-11)-induced gut toxicity and resulting diarrhea. Previous work from our lab indicated the protective effect of Gegen Qinlian decoction; given this, we further speculated that Gegen Qinlian Pill (GQP) would exhibit similar therapeutic effects. The effective material basis as well as potential mechanisms underlying the effect of GQP for the treatment of CPT-11-induced diarrhea have not been fully elucidated. Aim of the studyThe application of natural extracts or compounds derived from Chinese medicine is deemed to a promising strategy to prevent irinotecan (CPT-11)-induced gut toxicity. The aim of this study was to investigated the beneficial effects of GQP on CPT-11-induced gut toxicity and further explored its anti-diarrheal mechanism. MethodsFirst, the beneficial effect of GQP in alleviating diarrhea in mice following CPT-11 administration was investigated. We also obtained the effective ingredients in GQP from murine serum samples using HPLC-Q-TOF-MS analysis. Based on these active components, we next established an interaction network linking “compound-target-pathway”. Finally, a predicted mechanism of action was obtained using in vivo GQP validation based on Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. ResultsA total of 19, GQP-derived chemical compounds were identified in murine serum samples. An interaction network linking “compound-target-pathway” was then established to illuminate the interaction between the components present in serum and their targets that mitigated diarrhea. These results indicated GQP exerted a curative effect on diarrhea and diarrhea-related diseases through different targets, which cumulatively regulated inflammation, oxidative stress, and proliferation processes. ConclusionTaken together, this study provides a feasible strategy to elucidate the effective constituents in traditional Chinese medicine formulations. More specifically, this work detailed the basic pharmacological effects and underlying mechanism behind GQP's effects in the treatment of CPT-11-induced gut toxicity.

Chemotherapeutics-Induced Intestinal Mucositis: Pathophysiology and Potential Treatment Strategies.

The gastrointestinal tract is particularly vulnerable to off-target effects of antineoplastic drugs because intestinal epithelial cells proliferate rapidly and have a complex immunological interaction with gut microbiota. As a result, up to 40–100% of all cancer patients dosed with chemotherapeutics experience gut toxicity, called chemotherapeutics-induced intestinal mucositis (CIM). The condition is associated with histological changes and inflammation in the mucosa arising from stem-cell apoptosis and disturbed cellular renewal and maturation processes. In turn, this results in various pathologies, including ulceration, pain, nausea, diarrhea, and bacterial translocation sepsis. In addition to reducing patient quality-of-life, CIM often leads to dose-reduction and subsequent decrease of anticancer effect. Despite decades of experimental and clinical investigations CIM remains an unsolved clinical issue, and there is a strong consensus that effective strategies are needed for preventing and treating CIM. Recent progress in the understanding of the molecular and functional pathology of CIM had provided many new potential targets and opportunities for treatment. This review presents an overview of the functions and physiology of the healthy intestinal barrier followed by a summary of the pathophysiological mechanisms involved in the development of CIM. Finally, we highlight some pharmacological and microbial interventions that have shown potential. Conclusively, one must accept that to date no single treatment has substantially transformed the clinical management of CIM. We therefore believe that the best chance for success is to use combination treatments. An optimal combination treatment will likely include prophylactics (e.g., antibiotics/probiotics) and drugs that impact the acute phase (e.g., anti-oxidants, apoptosis inhibitors, and anti-inflammatory agents) as well as the recovery phase (e.g., stimulation of proliferation and adaptation).

Translational model of melphalan-induced gut toxicity reveals drug-host-microbe interactions that drive tissue injury and fever

PurposeConditioning therapy with high-dose melphalan (HDM) is associated with a high risk of gut toxicity, fever and infections in haematopoietic stem cell transplant (HSCT) recipients. However, validated preclinical models that adequately reflect clinical features of melphalan-induced toxicity are not available. We therefore aimed to develop a novel preclinical model of melphalan-induced toxicity that reflected well-defined clinical dynamics, as well as to identify targetable mechanisms that drive intestinal injury.MethodsMale Wistar rats were treated with 4–8 mg/kg melphalan intravenously. The primary endpoint was plasma citrulline. Secondary endpoints included survival, weight loss, diarrhea, food/water intake, histopathology, body temperature, microbiota composition (16S sequencing) and bacterial translocation.ResultsMelphalan 5 mg/kg caused self-limiting intestinal injury, severe neutropenia and fever while impairing the microbial metabolome, prompting expansion of enteric pathogens. Intestinal inflammation was characterized by infiltration of polymorphic nuclear cells in the acute phases of mucosal injury, driving derangement of intestinal architecture. Ileal atrophy prevented bile acid reabsorption, exacerbating colonic injury via microbiota-dependent mechanisms.ConclusionWe developed a novel translational model of melphalan-induced toxicity, which has excellent homology with the well-known clinical features of HDM transplantation. Application of this model will accelerate fundamental and translational study of melphalan-induced toxicity, with the clinical parallels of this model ensuring a greater likelihood of clinical success.Graphic abstract

Geophagy by Blackbucks on Termite Mounds: Unveiling a New Aspect of Dietary Predilection by Antelopes

A routine survey in blackbuck habitats in Bhetnoi region of Ganjam district in Odisha, India revealed an interesting behaviour of blackbucks, with a sub-adult male blackbuck licking and consuming the termite mound’s soils. To the best of our knowledge, this phenomenon has never been observed for blackbucks. This finding was reconfirmed on subsequent visits, with this behaviour being observed in 30% of total survey periods. This phenomenon is seen in a variety of mammals, birds, reptiles, butterflies, and isopods, especially herbivorous isopods. It serves as a mineral supplement for the animal, as well as providing gastrointestinal relief and lowering gut toxicity. This observation provides impetus to articulate research questions regarding blackbucks' dietary habits in relation to termite mounds, and any knowledge on the nutrient/element composition of such termite mounds will reveal interesting facts and information that will help in a better understanding of the function of termite mounds in the diet of antelopes, especially blackbucks.

You are what you eat: relative importance of diet, gut microbiota and nestmates for honey bee, Apis mellifera, worker health

In eusocial honey bees, Apis mellifera, diet, gut microbiota and nestmates can all contribute to the health of freshly emerged individual workers, but their relative importance for longevity and body weight is currently unknown. Here, we show that diet is most relevant, followed by gut microbiota and the presence of nestmates. Freshly emerged workers were randomly assigned to eight treatments (with or without honey/pollen, protein-substitute lactalbumin, antibiotic tetracycline and nestmates for 24 h) and maintained under standardised laboratory conditions. Longevity and food consumption were measured daily and fresh body weight was assessed at day 7. The data show a significantly better survival and a higher body weight in workers supplied with honey/pollen. Survival was higher in the lactalbumin treatments compared to the ones restricted to sucrose only, but lower compared to those with honey/pollen, highlighting the importance of micronutrients. In contrast, antibiotic treatment had a significant negative effect on longevity and body weight, which may be explained by inactivated gut microbiota and/or toxicity of the antibiotics. There was no positive effect of nestmates, probably due to the short exposure period. In contrast, nestmates showed a negative effect on survival in antibiotic-treated workers, possibly by transmitting pathogens and antibiotic-induced gut dysbiosis. In conclusion, a macro- and micronutrient-rich diet appears to be the key to individual honey bee worker health. Providing an optimal diet and possibly gut microbiota appears to be a promising way to promote managed A. mellifera health.

Inflammatory and Oxidative Pathways Are New Drug Targets in Multiple Episode Schizophrenia and Leaky Gut, Klebsiella pneumoniae, and C1q Immune Complexes Are Additional Drug Targets in First Episode Schizophrenia.

Breakdown of paracellular and vascular pathways and activated neuroimmune and oxidative pathways was established in (deficit) schizophrenia. The aim of this study was to delineate (a) the differences in these pathways between stable-phase, first (FES) and multiple (MES) episode schizophrenia and (b) the pathways that determine the behavioral-cognitive-physical-psychosocial (BCPS) deterioration in FES/MES. This study included 21 FES and 58 FES patients and 40 healthy controls and measured indicants of serum C1q circulating immune complexes (CIC), leaky gut, immune activation, and oxidative stress toxicity (OSTOX). We constructed a BCPS-worsening index by extracting a latent vector from symptomatic, neurocognitive, and quality of life data. FES was associated with higher IgA CIC-C1q, IgA directed to cadherin, catenin, and plasmalemma vesicle-associated protein, and IgA/IgM to Gram-negative bacteria as compared with FES and controls. In FES patients, the BCPS-worsening score was predicted (48.7%) by IgA to Klebsiella pneumoniae and lowered paraoxonase 1 activity. In MES patients, the BCPS-worsening score was explained (42.7%) by increased tumor necrosis factor-α, OSTOX, and number of episodes. In schizophrenia, 34.0% of the variance in the BCPS-worsening score was explained by IgA to K. pneumoniae, OSTOX, and number of episodes. Increased IgA to K. pneumoniae was the single best predictor of residual psychotic symptoms in FES and MES. This study delineated different mechanistic processes in FES, including breakdown of adherens junctions, bacterial translocation, and IgA CIC-C1q formation, and MES, including immune and oxidative neurotoxic pathways. FES and MES comprise different staging subtypes, i.e., FES and MES with and without worsening.

ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN FANCONI ANEMIA; A SINGLE CENTRE EXPERIENCE

Objective: To determine the treatment outcome of Hematopoietic stem cell transplantation in Fanconi Anemia.&#x0D; Study Design: Case series.&#x0D; Place and Duration of Study: Armed Forces Bone Marrow Transplant Center, Rawalpindi, from Jan 2001 to Jun 2018.&#x0D; Methodology: Data of all Fanconi anemia patients who had fully HLA matched bone marrow transplant during this period was analysed for variables affecting the outcome in terms of overall survival. Those fanconi anemia patients who had myelodysplastic changes or acute myeloid leukemia were excluded.&#x0D; Results: Total 27 patients underwent fully HLA matched allogeneic bone marrow transplant for Fanconi Anemia. Mean age of patients at transplant was 12.12 ± 5.16 years. All patients at transplant were in aplastic phase. Conditioning was done with fludarabine 120mg/m2 , ATG 20 mg/kg and Cyclophosphamide at a dose of 20-40 mg/kg. Mean time to neutrophil engraftment was 12.3 ± 2.92days and for platelets 20 ± 10.3 days. Major posttransplant complications were neutropenic fever in 26 (96%), hypertension in 18 (66.6%), mucositis in 12 (44.4%), azotaemia in 8 (29.6%), gut toxicity in 7 (25.9%) and haemorrhagic cystitis in 5 (18.5%) patients. Four patients (14.8%) had acute graft versus host disease while 7 (26%) patients had chronic GVHD. Overall survival at 6 months, 1, 5 and 8 years was 67%, 63%, 59% and 55% respectively. While overall survival in patients transplanted at younger age (&lt;11 years) was 81.8% compared to 37.5% in older age group (&gt;11years) and was statistically significant (p-value = 0.03).&#x0D; Conclusion: Our study demonstrated...................

BDE-209 caused gut toxicity through modulating the intestinal barrier, oxidative stress, autophagy, inflammation, and apoptosis in mice

Abstract Decabromodiphenyl ether (BDE-209), a congener of polybrominated diphenyl ethers (PBDEs), is used as a flame retardant and accounts for over 82% of total PBDE usage. BDE-209 has been found to be persistent in indoor and outdoor environments and has adverse health effects on humans. This study aimed to investigate the effects of BDE-209 on mouse intestinal tissues and reveal the underlying toxicological mechanisms. In this study, C57BL/6J male mice were administered BDE-209 intragastrically (200 mg/kg bodyweight) once a day for 4 weeks, after which intestinal tissues, blood samples, and fecal samples were collected for analysis. The results showed that BDE-209 exposure significantly decreased body weight (P

Chronic exposure to PPCPs mixture at environmentally relevant concentrations (ERCs) altered carbohydrate and lipid metabolism through gut and liver toxicity in zebrafish.

Pharmaceuticals and personal care products (PPCPs) have been widely distributed and posed ecotoxicological risks in the aquatic environment. This study aims to evaluate the toxic effects after chronic exposure to PPCPs mixture at the environment relevant concentrations (ERCs). Our results indicated that PPCPs induced serious metabolic effects by disturbing the carbohydrate and lipid metabolism pathways. Chronic exposure caused a significant reduction in the hepatosomatic index (HSI), the gut weight ratios, and histological alterations in liver and gut tissues. Further, exposure to the combined PPCPs disrupted the carbohydrate metabolism via significant upregulation of hk1, gk, pck1, and insr genes. The lipid metabolism was affected with higher ppars expression levels that increased the fatty acid β-oxidation and ultimately decreased the lipidogenesis. Moreover, the altered responses of the insulin growth factor (IGF) pathway more in male gut tissue than that of female revealed sex-dependent disturbance in the gut homeostasis induced by PPCPs mixture. In conclusion, chronic exposure to PPCPs mixtures at ERCs can induce developmental effects and metabolic dysfunction in both male and female fish. The consumption and environmental disposal of these PPCPs should be regulated to ensure ecological health and environmental safety.

Low concentrations of imidacloprid exposure induced gut toxicity in adult zebrafish (Danio rerio)

Neonicotinoid insecticide imidacloprid (IMI) is widely used in agriculture, and its repeated application may result in environmental pollution. Recently, the toxicity of IMI to non-target animals has received increasing attention. In the current study, adult zebrafish were exposed to low concentrations of IMI (100 and 1000 μg/L) for 21 days. The results showed that IMI exposure induced intestinal histological injury and oxidative stress in the gut of zebrafish, and the levels of superoxide dismutase (SOD), catalase (CAT) were noticeably increased. Furthermore, IMI exposure also resulted in higher intestinal LPS levels and significant increases in the expression of inflammatory factors. Simultaneously, IMI exposure also slightly induced gut microbiota dysbiosis and specific bacteria alterations. These findings indicated that low concentrations of IMI could induce gut toxicity in adult zebrafish, which could provide new insights into the potential risks of IMI to aquatic animals.

Impact of abdominal or pelvic radiotherapy on disease activity in inflammatory bowel disease: a multicentre cohort study from the GETAID.

Abdominal or pelvic radiotherapy in inflammatory bowel disease (IBD) patients raises concerns regarding the risk of worsening of underlying disease. To assess the impact of radiotherapy on IBD course. A retrospective multicentre study including IBD patients exposed to abdominal or pelvic irradiation was conducted, retrieving IBD activity by semester (6-month periods) before (from S-4 to S-1) and after (from S+1 to S+6) radiotherapy and IBD flare during follow-up. Sixty-one patients (32 women, mean age 59years), with 467 patient semesters of follow-up, treated for digestive (n=31), urinary tract (n=23) and gynaecological cancers (n=7) were included. Rates of IBD activity per semester were, respectively, 21% (95% CI: 16-27) from S-4 to S-1; 12% (7-19) from S+1 to S+3 (P=0.15 vs S-4 to S-1) and 16% (10-25) from S+4 to S+6 (P=0.45 vs S-4 to S-1). With a median follow-up of 156 weeks (interquartile range: 82-365), rates of survival without IBD flare at 1 and 3years after radiotherapy were 82.5% (73.2-93.0) and 70.6% (58.8-84.7). Moderate-to-severe acute radiotherapy-induced gut toxicity and the absence of concomitant chemotherapy were independently associated with an increased risk of flare. Most patients with non-active IBD can be safely treated with abdominal or pelvic radiotherapy. Patients having acute gut toxicity and those without concomitant chemotherapy should be more closely monitored in the post-radiotherapy period.

Tumor necrosis factor alpha blockade prevents immune checkpoint inhibitor therapy-related cardiotoxicity

Abstract Background Increasing use of immune checkpoint inhibitor (ICI) therapy has recently been associated with latent left ventricular dysfunction as a common cardiotoxic side effect during early therapy. Considering the potential impact on morbidity and mortality, strategies to prevent ICI-related cardiotoxicity are urgently needed, but established immunosuppressive measures prevent the anti-tumor effect of the ICI therapy, thereby limiting its applicability to severe, life-threatening cases. Recently, tumor necrosis factor alpha (TNFα) blockade was shown to prevent ICI-related gut toxicity while preserving, or even enhancing, anti-tumor efficacy. Purpose This study aims to investigate a cardioprotective effect of TNFα blockade during anti programmed death 1 (PD1) ICI therapy in a preclinical model as a basis for a potential new, preventive therapeutic approach for ICI-related cardiotoxicity. Methods A melanoma mouse model was established as the basis to study PD1 blocking therapy and protective measures in a preclinical setting. Mice were subcutaneously transplanted with a syngeneic melanoma cell line and treated with anti-PD1 antibodies for 15 days. Response to therapy was monitored by assessment of tumor size. Cardiotoxicity was confirmed by mouse echocardiography. Mice were then simultaneously treated with anti-PD1 antibodies and TNFα-blocking antibodies. A cardioprotective effect was evaluated by echocardiography and flow cytometry was used to characterize myocardial immune cells. Results Mice receiving anti-PD1 showed smaller tumor sizes with increased immune cell infiltration compared to control littermates as a sign for a profound response to therapy. Cardiotoxicity was confirmed as demonstrated by reduced left ventricular ejection fraction and reduced global radial strain in anti-PD1-treated mice. Mice receiving anti-PD1 ICI therapy showed 2-fold elevated concentrations of CD4+ and CD8+ T-lymphocytes in the murine heart as determined by flow cytometry. CD44 expression was upregulated in cytotoxic T-cells as a marker of enhanced T-cell activity in anti-PD1 treated mice. Administration of TNFα-blocking antibodies did not alter tumor sizes during anti-PD1 treatment as a sign for a sustained response to therapy. Remarkably, mice receiving TNFα-blocking antibodies together with anti-PD1 ICI therapy showed increased left ventricular function compared to mice receiving anti-PD1 monotherapy. Flow cytometry revealed increased expression of T cell exhaustion markers in mice receiving TNFα blockade as a potential underlying mechanism. Conclusions ICI therapy targeting PD1 induces latent cardiotoxicity with left ventricular dysfunction. TNFα blockade may serve as a novel cardioprotective treatment without compromising the anti-tumor efficacy of ICI therapy. Prospective studies are needed to further characterize ICI-related cardiotoxicity in patients and to evaluate the cardioprotective effect of TNFα blockade. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): IFORES research grant, Medical Faculty, University Duisburg-Essen, Essen, Germany

Repeated exposure of Caco-2 versus Caco-2/HT29-MTX intestinal cell models to (nano)silver in vitro: Comparison of two commercially available colloidal silver products

Colloidal silver products are sold for a wide range of disinfectant and health applications. This has increased the potential for human exposure to silver nanoparticles (AgNPs) and ions (Ag+), for which oral ingestion is considered to be a major route of exposure. Our objective was to evaluate and compare the toxicity of two commercially available colloidal silver products on two human intestinal epithelial models under realistic exposure conditions.Mesosilver™ and AgC were characterized and a concentration range between 0.1 and 12 μg/mL chosen. Caco-2 cells vs. co-culture of Caco-2 and mucus-secreting HT29-MTX cells (90/10) were used. Repeated exposure was carried out to determine cell viability over 18 days of cell differentiation in 24-well plates. Selected concentrations (0.1, 1, and 3 μg/mL) were tested on cells cultured in E-plates and Transwells with the same repeated exposure regimen, to determine cell impedance, and cell viability and trans-epithelial electrical resistance (TEER), respectively. Silver uptake, intracellular localisation, and translocation were determined by CytoViva™, HIM-SIMS, and ICP-MS. Genotoxicity was determined on acutely-exposed proliferating Caco-2 cells by γH2AX immunofluorescence staining.Repeated exposure of a given concentration of AgC, which is composed solely of ionic silver, generally exerted more toxic effects on Caco-2 cells than Mesosilver™, which contains a mix of AgNPs and ionic silver. Due to its patchy structure, the presence of mucus in the Caco-2/HT29-MTX co-culture only slightly mitigated the deleterious effects on cell viability. Increased genotoxicity was observed for AgC on proliferating Caco-2 cells. Silver uptake, intracellular localisation, and translocation were similar.In conclusion, Mesosilver™ and AgC colloidal silver products show different levels of gut toxicity due to the forms of distinct silver (AgNPs and/or Ag+) contained within. This study highlights the applicability of high-resolution (chemical) imaging to detect and localize silver and provides insights into its uptake mechanisms, intracellular fate and cellular effects.

Acute non-hematological toxicity of intensive chemotherapy of acute lymphoblastic leukemia in children

AbstractIntroductionLeukemia belong to 31% of all childhood malignancies. Acute lymphoblastic leukemia (ALL) is the most frequent type of pediatric leukemia accounting for 80–85% of all cases. Progress in diagnostics and therapy of leukemia is dependent on international cooperation. The objective of the study was the analysis of non-hematological toxicity during intensive chemotherapy according to two consecutive intercontinental protocols.Patients and methodsA total number of 210 children diagnosed for ALL who were treated in single center between 2002 and 2018 were divided in two groups defined by therapeutic protocol: ALL IC-BFM 2002 (group 1) and ALL IC-BFM 2009 (group 2). Data were entered prospectively from 2002 into international ALL IC-BFM 2002 and ALL IC-BFM 2009 registry. Non-hematological toxicity was analyzed according to the criteria followed in protocols, compatible with CTCAE criteria.ResultsThe most frequent toxicities included hepatic toxicity with transaminitis and hyperbilirubinemia, infections, oral mucositis and gut toxicity with vomiting, and/or diarrhea. Non-hematological toxicity episodes calculated as a ratio per patient were comparably often observed in both the groups; however, the distribution was different. There were more grade III and less grade II toxicities. This was mainly related to significant increase in the rates of infections and transaminitis. However, there was a significant decrease in vomiting and central and peripheral neurotoxicity.ConclusionsIntensive treatment of ALL is burdened with frequent severe toxic and infectious complications. Further progress in therapy of pediatric ALL is dependent on sophisticated supportive therapy and very well experienced and knowledgeable therapeutic team.

Prevotella copri is associated with carboplatin-induced gut toxicity

As a widely used cancer drug, carboplatin often results in serious side effects, such as gut toxicity. In this study, we examined the effects of gut microbiota on mice with carboplatin-induced intestinal mucosal damage. Carboplatin resulted in intestinal mucositis, as indicated by weight loss, diarrhoea, and infiltration of inflammatory cells. It markedly increased the expression of inflammatory cytokines/chemokines in intestine. Carboplatin also altered the diversity and composition of the gut microbiota. A significantly higher abundance of Prevotella copri (P. copri) was observed in carboplatin-treated mice. Moreover, the content of P. copri was positively correlated with the severity of intestinal mucositis. Pretreatment with metronidazole reduced the content of P. copri and relieved the intestinal mucosal injury and inflammation that was induced by carboplatin. Further study revealed that supplementation with P. copri in carboplatin-treated mice resulted in more severe tissue damage, lower tight junction protein expression and higher cytokine expression, and it enhanced both local and systemic immune responses. These data demonstrated that P. copri was involved in the pathological process of carboplatin-induced intestinal mucositis, suggesting a potential attenuation of carboplatin-induced intestinal mucositis by targeting P. copri.

Effect of rice bran fermented with Saccharomyces cerevisiae and Lactobacillus plantarum on gut microbiome of mice fed high-sucrose diet.

To clarify the effect of rice bran (RB) and fermented RB (FRB) in a high-sucrose and low-dietary fibre diet on the gut microbiome, the in vitro bile acid-lowering capacity and caecal microbiota of ICR mice fed with 20% RB or FRB diets for two weeks were determined. The caecal microbiome was analysed by 16S rRNA gene amplicon sequencing. The in vitro bile acid-lowering capacity was high for FRB. In mouse experiments, triacylglycerol and total cholesterol were generally lower with FRB, although the faecal frequency was highest in mice fed with RB. The Shannon-Wiener and Simpson's indices for alpha-diversity in the microbiome of mice fed with RB and FRB, were higher than mice fed the control diet. At the phylum level in the caecal microbiome, Firmicutes and Bacteroidetes were high with FRB and RB, respectively. At the operational taxonomic unit level, some bacterial groups related to diabetes and gut toxicity, such as Lachnospiraceae and Enterorhabdus mucosicola, were high for RB but not for FRB diets. These results suggest that FRB, rather than RB, intake improve the intestinal environment and blood lipid condition.

Subchronic exposure of environmentally relevant concentrations of F-53B in mice resulted in gut barrier dysfunction and colonic inflammation in a sex-independent manner

F-53B (6:2 chlorinated polyfluorinated ether sulfonate) is currently recognized as a safe alternative to long-chain PFASs in China. However, an increasing number of studies have recently authenticated its biotoxicological effects. In this study, for evaluating the gut toxicity of F-53B in mammals, both female and male mice were orally exposed to 0, 1, 3, or 10 μg/L F-53B for 10 weeks. Our results showed that F-53B significantly accumulated in the colon, ileum and serum when exposed to 10 μg/L F-53B for 10 weeks. F-53B exposure not only increased the transcriptional levels of ion transport-related genes but could also interact with the CFTR protein directly. Interestingly, subchronic F-53B exposure also increased the transcription of mucus secretion-related genes, but the protein level of Muc2 decreased after F-53B exposure, indicating that there was a compensatory phenomenon after mucus barrier injury. Furthermore, F-53B exposure also induced colonic inflammation associated with gut microbiota dysbiosis in the colon. Taken together, our results indicated that the potential gut toxicity of F-53B and almost all of the changed parameters were significantly affected in both female and male mice, suggesting that F-53B could disturb the gut barrier without sex dependence in mice.

Abstract 103: Disruption of Notch Signaling targeted to the myeloma bone marrow microenvironment simultaneously inhibits tumor growth and prevents bone loss without inducing gut toxicity

Abstract Communication between myeloma (MM) cells and cells of the bone marrow via Notch signaling promotes tumor growth/survival and stimulates bone resorption. Systemic inhibition of Notch, using γ-secretase inhibitors (GSIs), decreases MM growth and reduces bone destruction, but the clinical use of GSIs is limited due to dose-limiting severe gut toxicity. To circumvent GSI side effects, we generated a bone specific Notch inhibitor (BT-GSI) by conjugating GSI-XII to a targeting molecule (BT) with high bone affinity using an acid hydrolyzable linker. In vitro, BT-GSI was inactive unless pre-incubated at low pH, and exhibited equal inhibition of Notch target genes in MM cells as unconjugated GSI. Ex vivo, BT-GSI decreased Notch expression and reduced MM growth in bone organ cultures that reproduce acidic conditions in the MM-bone microenvironment. In vivo, treatment with BT-GSI (5mg/kg/3x/wk, i.p.) for 2 wks decreased Notch signaling in bone more efficiently than unconjugated GSI (10mg/kg/5x/wk, i.p.) in naïve mice. In addition, BT-GSI increased cancellous bone mass (30%) and decreased bone resorption by 40%, without affecting bone formation. In contrast, these parameters remained unchanged by GSI. Next, we examined in vivo the impact of BT-GSI on MM growth and bone disease in a preclinical model of established MM. 8-wk-old immunodeficient mice were injected intratibially with 105 JJN3 human MM (hMM) cells or saline. hMM injected mice exhibited detectable serum levels of the tumor biomarker human K-light chain (40 ng/mL) and visible osteolytic disease (osteolytic area 1.7 mm2) 3 wks after hMM inoculation. Then, hMM-injected mice were randomized based on tumor levels to two subgroups to receive either BT-GSI (10mg/kg/3x/wk) or vehicle (DMSO) for 3 wks. Saline-injected mice received vehicle injections. BT-GSI selectively decreased Notch gene expression in bone, but had no effect in the brain or gut. Further, BT-GSI did not increase the expression of Adipsin in the gut, a biomarker of gut toxicity, nor showed evidence of gut toxicity at necropsy. Mice treated with BT-GSI exhibited a 45% decrease in tumor burden (168 vs 254 ng/mL human K-light chain) and 50% less osteolytic area compared to vehicle treated mice bearing hMM (4.4 vs 10.2 mm2). Moreover, BT-GSI decreased serum CTX by 30%, but did not affect serum P1NP. Importantly, equimolar administration of the unconjugated BT molecule did not alter MM growth nor prevented bone loss in mice with established MM. In conclusion, these results show that bone-targeted Notch inhibition reduces MM growth and preserves bone mass in mice with established MM. Because BT-GSI shows bone specific Notch inhibition and lacks gut toxicity, it should circumvent the deleterious side effects that limit GSI use in patients. Thus, BT-GSI is a promising approach to inhibit MM growth and to prevent bone loss in MM patients. Citation Format: Adam J. Ferrari, Kevin McAndrews, Jessica H. Nelson, James T. Bell, Venkatesan Srinivasan, Frank H. Ebetino, Robert K. Boeckman Jr, G. David Roodman, Teresita Bellido, Jesus Delgado-Calle. Disruption of Notch Signaling targeted to the myeloma bone marrow microenvironment simultaneously inhibits tumor growth and prevents bone loss without inducing gut toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 103.