Administration of intestinal mesenchymal stromal cells reduces colitis-associated cancer in C57BL/6J mice modulating the immune response and gut dysbiosis

BACKGROUND

Patients with inflammatory bowel disease (IBD) have a higher risk of developing colitis-associated colorectal cancer (CAC) with poor prognosis. IBD etiology remains undefined but involves environmental factors, genetic predisposition, microbiota imbalance (dysbiosis) and mucosal immune defects. Mesenchymal stromal cell (MSC) injections have shown good efficacy in reducing intestinal inflammation in animal and human studies. However, their effect on tumor growth in CAC and their capacity to restore gut dysbiosis are not clear.

METHODS

The outcome of systemic administrations of in vitro expanded human intestinal MSCs (iMSCs) on tumor growth in vivo was evaluated using the AOM/DSS model of CAC in C57BL/6J mice. Innate and adaptive immune responses in blood, mesenteric lymph nodes (MLNs) and colonic tissue were analyzed by flow cytometry. Intestinal microbiota composition was evaluated by 16S rRNA amplicon sequencing.

RESULTS

iMSCs significantly inhibited colitis and intestinal tumor development, reducing IL-6 and COX-2 expression, and IL-6/STAT3 and PI3K/Akt signaling. iMSCs decreased colonic immune cell infiltration, and partly restored intestinal monocyte homing and differentiation. iMSC administration increased the numbers of Tregs and IFN-γ+CD8+ T cells in the MLNs while decreasing the IL-4+Th2 response. It also ameliorated intestinal dysbiosis in CAC mice, increasing diversity and Bacillota/Bacteroidota ratio, as well as Akkermansia abundance, while reducing Alistipes and Turicibacter, genera associated with inflammation.

CONCLUSION

Administration of iMSCs protects against CAC, ameliorating colitis and partially reverting intestinal dysbiosis, supporting the use of MSCs for the treatment of IBD.

Tigecycline reduces tumorigenesis in colorectal cancer via inhibition of cell proliferation and modulation of immune response

BACKGROUND

and Purpose: Colorectal cancer (CRC) is one of the cancers with the highest incidence in which APC gene mutations occur in almost 80% of patients. This mutation leads to β-catenin aberrant accumulation and an uncontrolled proliferation. Apoptosis evasion, changes in the immune response and microbiota composition are also events that arise in CRC. Tetracyclines are drugs with proven antibiotic and immunomodulatory properties that have shown cytotoxic activity against different tumor cell lines.

EXPERIMENTAL APPROACH

The effect of tigecycline was evaluated in vitro in HCT116 cells and in vivo in a colitis-associated colorectal cancer (CAC) murine model. 5-fluorouracil was assayed as positive control in both studies.

KEY RESULTS

Tigecycline showed an antiproliferative activity targeting the Wnt/β-catenin pathway and downregulating STAT3. Moreover, tigecycline induced apoptosis through extrinsic, intrinsic and endoplasmic reticulum pathways converging on an increase of CASP7 levels. Furthermore, tigecycline modulated the immune response in CAC, reducing the cancer-associated inflammation through downregulation of cytokines expression. Additionally, tigecycline favored the cytotoxic activity of cytotoxic T lymphocytes (CTLs), one of the main immune defenses against tumor cells. Lastly, the antibiotic reestablished the gut dysbiosis in CAC mice increasing the abundance of bacterial genera and species, such as Akkermansia and Parabacteroides distasonis, that act as protectors against tumor development. These findings resulted in a reduction of the number of tumors and an amelioration of the tumorigenesis process in CAC.

CONCLUSION AND IMPLICATIONS

Tigecycline exerts a beneficial effect against CRC supporting the use of this antibiotic for the treatment of this disease.

The Prebiotic Effects of an Extract with Antioxidant Properties from Morus alba L. Contribute to Ameliorate High-Fat Diet-Induced Obesity in Mice

Obesity is a global health issue, in which modifications in gut microbiota composition have a key role. Different therapeutic strategies are being developed in combination with diet and exercise, including the use of plant extracts, such as those obtained from Morus alba L. leaves. Recent studies have revealed their anti-inflammatory and antioxidant properties. The aim of the present work was to evaluate whether the beneficial effects of M. alba L. leaf extract in high-fat diet-induced obesity in mice is correlated with its impact on gut microbiota. The extract reduced body weight gain and attenuated lipid accumulation, as well as increased glucose sensitivity. These effects were associated with an amelioration of the obesity-associated inflammatory status, most probably due to the described antioxidant properties of the extract. Moreover, M. alba L. leaf extract mitigated gut dysbiosis, which was evidenced by the restoration of the Firmicutes/Bacteroidota ratio and the decrease in plasma lipopolysaccharide (LPS) levels. Specifically, the extract administration reduced Alistipes and increased Faecalibaculum abundance, these effects being correlated with the beneficial effects exerted by the extract on the obesity-associated inflammation. In conclusion, anti-obesogenic effects of M. alba L. leaf extract may be mediated through the amelioration of gut dysbiosis.

The Antioxidant Properties of Lavandula multifida Extract Contribute to Its Beneficial Effects in High-Fat Diet-Induced Obesity in Mice

Obesity is a worldwide public health problem whose prevalence rate has increased steadily over the last few years. Therefore, it is urgent to improve the management of obesity and its comorbidities, and plant-based treatments are receiving increasing attention worldwide. In this regard, the present study aimed to investigate a well-characterized extract of Lavandula multifida (LME) in an experimental model of obesity in mice and explore the underlying mechanisms. Interestingly, the daily administration of LME reduced weight gain as well as improved insulin sensitivity and glucose tolerance. Additionally, LME ameliorated the inflammatory state in both liver and adipose tissue by decreasing the expression of various proinflammatory mediators (Il-6, Tnf-α, Il-1β, Jnk-1, Pparα, Pparγ, and Ampk) and prevented increased gut permeability by regulating the expression of mucins (Muc-1, Muc-2, and Muc-3) and proteins implicated in epithelial barrier integrity maintenance (Ocln, Tjp1, and Tff-3). In addition, LME showed the ability to reduce oxidative stress by inhibiting nitrite production on macrophages and lipid peroxidation. These results suggest that LME may represent a promising complementary approach for the management of obesity and its comorbidities.

Analytical Platform for the Study of Metabolic Pathway of Propyl Propane Thiosulfonate (PTSO) from Allium spp

The present work is focused on the development of an analytical platform to elucidate the metabolic pathway of PTSO from onion, an organosulfur compound well-known for its functional and technological properties and its potential application in animal and human nutrition. This analytical platform consisted of the use of gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography quadrupole with time-of-flight MS (UHPLC-Q-TOF-MS) in order to monitor volatile and non-volatile compounds derived from the PTSO. For the extraction of the compounds of interest, two different sample treatments were developed: liquid-liquid extraction (LLE) and salting-out assisted liquid-liquid extraction (SALLE) for GC-MS and UHPLC-Q-TOF-MS analysis, respectively. Once the analytical platform was optimised and validated, an in vivo study was planned to elucidate PTSO metabolisation, revealing the presence of dipropyl disulfide (DPDS) in liver samples with concentrations between 0.11 and 0.61 µg g^-1. The DPDS maximum concentration in the liver was observed at 0.5 h after the intake. DPDS was also present in all plasma samples with concentrations between 2.1 and 2.4 µg mL^-1. In regard to PTSO, it was only found in plasma at times above 5 h (0.18 µg mL^-1). Both PTSO and DPDS were excreted via urine 24 h after ingestion.

The Antioxidant Activity of Thymus serpyllum Extract Protects against the Inflammatory State and Modulates Gut Dysbiosis in Diet-Induced Obesity in Mice

Nowadays, there is an increasing interest in alternative therapies in the treatment of metabolic syndrome that combine efficacy and safety profiles. Therefore, this study aimed to evaluate the effect of an extract of Thymus serpyllum, containing rosmarinic acid, on high-fat diet (HFD)-induced obesity mice, highlighting the impact of its antioxidant activity on the inflammatory status and gut dysbiosis. The extract was administered daily (50, 100 and 150 mg/kg) in HFD-fed mice. The treatment reduced body weight gain, glucose and lipid metabolic profiles. Moreover, the extract ameliorated the inflammatory status, with the c-Jun N-terminal kinases (JUNK) pathway being involved, and showed a significant antioxidant effect by the reduction of radical scavenging activity and the mitigation of lipid peroxidation. Moreover, the extract was able to modulate the altered gut microbiota, restoring microbial richness and diversity, and augmenting the counts of short-chain fatty acid producing bacteria, which have been associated with the maintenance of gut permeability and weight regulation. In conclusion, the antioxidant activity of Thymus serpyllum extract displayed a positive impact on obesity and its metabolic alterations, also reducing systemic inflammation. These effects may be mediated by modulation of the gut microbiota.

Silk fibroin nanoparticles enhance quercetin immunomodulatory properties in DSS-induced mouse colitis

Inflammatory bowel disease (IBD) is a chronic and idiopathic inflammatory disorder affecting the gastrointestinal tract. The pharmacological treatments used currently for its treatment lack efficacy, so new therapeutic strategies should be developed. In this context, flavonoids loaded in biopolymeric nanoparticles can be considered as novel promising candidates. The aim of the present study was to evaluate the intestinal anti-inflammatory effects of quercetin when is administered loaded in silk fibroin nanoparticles (QSFN) in the dextran sulphate sodium experimental model of mouse colitis, which displays some similarities to human IBD. Previously characterized quercetin-loaded silk fibroin nanoparticles (QSFN). QSFN showed a reversible aggregation profile induced by the acidification of the solution but did not affect the loaded quercetin. Daily administration of QSFN significantly reduced disease activity index values compared to the control colitic group. This beneficial effect was not only corroborated by the histological examination of the colonic specimens but also the improvement of the colonic expression of the different proinflammatory cytokines (Tnf-α, Il-1β, Il-6, Mcp-1, Icam-1, Nlrp3 and iNOS). Therefore, these data suggest that QSFN could be a promising alternative to current treatments as a drug delivery system for IBD treatment.

Lactobacillus fermentum CECT5716 ameliorates high fat diet-induced obesity in mice through modulation of gut microbiota dysbiosis

Obesity is one of the main features of metabolic syndrome, where a low-grade chronic inflammation and gut dysbiosis contribute to the development of the related metabolic dysfunctions. Different probiotics have demonstrated beneficial effects on this condition, increasing the interest in the development of probiotic treatments. Lactobacillus fermentum CECT5716 has shown anti-inflammatory effects and capacity to modulate microbiota composition in different experimental models. In this study, L. fermentum CECT5716 was evaluated in a model of high fat diet-induced obesity in mice. It exerts anti-obesity effects, associated with its anti-inflammatory properties and amelioration of endothelial dysfunction and gut dysbiosis. The probiotic restores Akkermansia sp. abundance and reduced Erysipelotrichi class and Clostridium spp presence as well as increased Bacteroides proportion. In conclusion, this probiotic represents a very interesting approach. Our findings describe, for the first time, the ability of this probiotic to ameliorate experimental obesity through microbiome modulation, affecting different bacteria that have been reported to play a key role in the pathogenesis of obesity. Therefore, this suggests a potential use of L. fermentum CECT5716 in clinical practice, also taking into account that probiotic treatments have demonstrated to be relatively safe and well tolerated.

Exopolysaccharide Producing Bifidobacterium animalis subsp. lactis Strains Modify the Intestinal Microbiota and the Plasmatic Cytokine Levels of BALB/c Mice According to the Type of Polymer Synthesized

Bacteria-host interactions are mediated by different microbial associated molecular patterns which are most often surface structures such as, among others, exopolysaccharides (EPSs). In this work, the capability of two isogenic EPS-producing Bifidobacterium animalis subsp. lactis strains to modulate the gut microbiota of healthy mice, was assessed. Each strain produces a different type of polymer; the ropy strain S89L synthesized a rhamnose-rich, high-molecular weight EPS in highest abundance than the non-ropy DMS10140 one. BALB/c mice were orally fed for 10 days with milk-bifidobacterial suspensions and followed afterward for 7 post-intervention days (wash-out period). The colonic content of mice was collected in several sampling points to perform a metataxonomic analysis. In addition, the influence of specific microbial clades, apparently stimulated by the ropy and non-ropy strains, on mouse plasmatic cytokine levels was investigated through hierarchical association testing. Analysis of 16S rRNA gene sequences showed that the abundance of Firmicutes phylum significantly increased 7 days after cessing the treatment with both strains. The relative abundance of Alloprevotella genus also rose, but after shorter post-treatment times (3 days for both DMS10140 and S89L strains). Some bacterial clades were specifically modulated by one or another strain. As such, the non-ropy DMS10140 strain exerted a significant influence on Intestinomonas genus, which increased after 4 post-administration days. On the other hand, feeding with the ropy strain S89L led to an increase in sequences of Faecalibaculum genus at 4 post-treatment days, while the abundance of Erysipelotrichaceae and Lactobacillaceae families increased for prolonged times. Association testing revealed that several lactobacilli and bifidobacterial significantly stimulated by ropy S89L strain were positively associated with the levels of certain cytokines, including IL-5 and IL-27. These results highlight relevant changes in mice gut microbiota produced after administration of the ropy S89L strain that were associated to a potential immune modulation effect.

Comparative Study of the Antioxidant and Anti-Inflammatory Effects of Leaf Extracts from Four Different Morus alba Genotypes in High Fat Diet-Induced Obesity in Mice

Increased levels of reactive oxygen species (ROS) and a low-grade chronic inflammation in multiple organs have been demonstrated in obesity. Morus alba leaves extracts (MAEs) have been used in traditional medicine as anti-inflammatory agents. In this work, the bioactive compounds of different genotypes of M. alba L. (Filipina, Valenciana Temprana, Kokuso, and Italia) were analyzed not only by reverse phase high performance liquid chromatography–electrospray ionization-time of flight-mass spectrometry (RP-HPLC-ESI-TOF-MS) and hydrophilic interaction chromatography–electrospray ionization-time of flight-mass spectrometry (HILIC-ESI-TOF-MS), but also screened for in vitro and in vivo antioxidant activity by means of DPPH• radical scavenging assay and Caenorhabditis elegans model. These MAEs were administered daily in a model of diet-induced obesity in mice. Filipina and Italia genotypes significantly reduced weight gain, the glycemic levels in high fat diet, as well as, levels of LDL-cholesterol and triglycerides. Filipina and Italia MAEs also reduced the expression of proinflammatory mediators such as Tnf-α, Il-1β, Il-6 and increased the levels of adiponectin and AMPK, which exert anti-inflammatory effects. Moreover, Italia genotype ameliorated the intestinal barrier function. In conclusion, Filipina and Italia methanolic extracts show the highest antioxidant and anti-inflammatory effect, due to the presence of compounds such as protocatechuic acid or quercetin-3-glucoside, and they could be developed as a complementary treatment for obesity and metabolic disorders.

Anti-Inflammatory and Chemopreventive Effects of Bryophyllum pinnatum (Lamarck) Leaf Extract in Experimental Colitis Models in Rodents

Inflammatory bowel diseases, mainly ulcerative colitis and Crohn's disease are characterized by chronic inflammation in the intestine. Currently several therapeutic strategies available to treat inflammatory bowel diseases. Though, most treatments can be associated with serious adverse effects what justifies the search for new treatments. In this sense, we highlight the interest in herbal products rich in bioactive compounds which immunomodulatory and antioxidant properties as is the case of Bryophyllum pinnatum (Crassulaceae). This plant is used in traditional medicine in Brazil for treating inflammatory diseases. We hypothesized that hydroethanolic B. pinnatum leaf extract has intestinal anti-inflammatory effects on two experimental colitis models: 2.4-dinitrobenzene sulfonic acid (DNBS) in rats, and dextran sulfate sodium (DSS) in mice. Ultra-fast liquid chromatography method used for the quantification of the main compounds indicated good linearity, specificity, selectivity, precision, robustness and accuracy. The major flavonoids (mg/g of the extract) quantified were: quercetin 3-O-α-L-arabinopyranosyl-(1→2)-α-L-rhamnopyranoside (35.56 ± 0.086 mg/g), kaempferol 3-O-α-L-arabinopyranosyl-(1→2)-α-L-rhamnopyranoside (4.66 ± 0.076 mg/g) and quercetin-3-O-rhamnopyranoside (4.56 ± 0.026 mg/g). The results obtained in the DNBS and DSS models indicate that extract has both chemopreventive and anti-inflammatory effects, observing a significant reduction in the disease activity index score, and less macroscopic and microscopic damage. The extract promoted downregulation of Toll-like receptor and kappa B p65 nuclear factor gene expression, leading to a reduction in pro-inflammatory and oxidative mediators, chemokines, and cell adhesion molecules. This immunomodulatory property was proposed that one of the possible action mechanisms of extract. An improvement in intestinal damage was also associated with a reduction in oxidative stress and infiltration of leukocytes, as evidenced by the reduction in malonaldialdehyde and myeloperoxidase activity and increase in total glutathione in the colonic tissue. Moreover, the extract improved the cytoarchitecture of the colonic tissue and the integrity of the intestinal epithelial barrier by restoring the expression of the proteins associated with mucosa protection. In view of the beneficial effects showed by the B. pinnatum leaf extract in preclinical rodent models of colitis there is the potential to conduct some future clinical studies to ensure safe and effective development of a phytotherapeutic treatment for human inflammatory bowel diseases.

Recurrent infective endocarditis due to Aggregatibacter aphrophilus and Staphylococcus lugdunensis

Uncommon microorganisms are increasingly being recognized as causative agents of paediatric infectious endocarditis (IE). We report a 4-year old girl with congenital heart disease, who suffered from 2 IE episodes secondary to Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus) and Staphylococcus lugdunensis, both rarely reported pathogens in this age group. The patient was initially successfully treated with prolonged intravenous antibiotic courses, however removal of the Contegra valved conduit during the second episode was required due to recurrence of fever and development of pulmonary embolism despite completion of antibiotic therapy. A. aphrohilus is a member of the fastidious gram negative microorganisms of the HACEK group (Haemophilus spp., Aggregatibacter spp, Cardiobaterium hominis, Eikenella corrodens and Kingella kingae), that colonize the oropharynx and are a recognised cause of IE. Prognosis of children with IE due to HACEK group members varies, half of them suffering from complications and mortality rates of 10-12.5%. Although S. lugdunensis belongs to coagulase negative staphylococci (CONS), it behaves more like S. aureus species rather than CONS. This microorganism is a well-described cause of endocarditis in adult patients, associated with high requirements of surgical procedures and mortality (42-78%). In conclusion, paediatric IE can be caused by uncommon microorganisms associated with severe complications and potential fatality. The isolation of S. lugdunensis or A. aphrophilus in febrile patients should be considered clinically relevant and cardiac involvement must be ruled out. Those patients with proved IE will require prolonged intravenous antibiotic courses and in complicated cases surgical intervention.