Characterizing date seed polysaccharides: A comprehensive study on extraction, biological activities, prebiotic potential, gut microbiota modulation, and rheology using microwave-assisted deep eutectic solvent

This study investigated the biological activities, prebiotic potentials, modulating gut microbiota, and rheological properties of polysaccharides derived from date seeds via microwave-assisted deep eutectic solvent systems. Averaged molecular weight (246.5 kDa) and a monosaccharide profile (galacturonic acid: glucose: mannose: fructose: galactose), classifying MPS as a heteropolysaccharide. MPS, at concentrations of 125-1000 µg/mL, demonstrates increasing free radical scavenging activities (DPPH, ABTS, MC, SOD, SORS, and LO), potent antioxidant potential (FRAP: 51.2-538.3 µg/mL; TAC: 28.3-683.4 µg/mL; RP: 18.5-171.2 µg/mL), and dose-dependent antimicrobial activity against common foodborne pathogens. Partially-purified MPS exhibits inhibition against α-glucosidase (79.6 %), α-amylase (85.1 %), and ACE (68.4 %), along with 80 % and 46 % inhibition against Caco-2 and MCF-7 cancer cells, respectively. Results indicate that MPS fosters the growth of beneficial fecal microbiota, including Proteobacteria, Firmicutes, and Actinobacteria, supporting microbes responsible for major SCFAs (acetic, propionic, and butyric acids) production, such as Ruminococcus and Blautia.

Bioactive properties and gut microbiota modulation by date seed polysaccharides extracted using ultrasound-assisted deep eutectic solvent

Polysaccharides are abundant macromolecules. The study extracted date seed polysaccharides (UPS) using ultrasound-assisted deep eutectic solvent extraction to valorize date seeds. UPS were subjected to comprehensive characterization and evaluation of their bioactivity, prebiotic properties, and their potential to modulate the gut microbiome. Characterization revealed UPS's heteropolysaccharide composition with galactose, mannose, fructose, glucose, and galacturonic acid respectively in 66.1, 13.3, 9.9, 5.4, and 5.1%. UPS showed a concentration-dependent increase of radical scavenging and antioxidant activities, evidenced by FRAP, TAC, and RP assays. They also displayed antimicrobial efficacy against E. coli O157:H7, S. typhimurium, S. aureus, and L. monocytogenes. Rheological analysis showed UPS's elastic-dominant nature with thixotropic tendencies. UPS inhibited α-glycosidase, α-amylase, and ACE up to 86%, and reduced Caco-2 and MCF-7 cell viability by 70% and 46%, respectively. UPS favored beneficial gut microbiota growth, releasing significant SCFAs during fecal fermentation.

Gut microbiota modulation, prebiotic and bioactive characteristics of date pomace polysaccharides extracted by microwave-assisted deep eutectic solvent

This study investigated the characteristics of polysaccharides from date pomace using microwave-assisted deep eutectic solvents. The impact on the gut microbiota and probiotics growth was examined in vitro. The study also examined its antioxidant properties, ability to inhibit enzymes linked to diabetes and high blood pressure, impact on cell growth, and physical properties. The isolated MPS had an average molecular weight of 8073.38 kDa and contained mannose, galacturonic acid, galactose, glucose, and fructose in specific proportions. At a concentration of 1000 mg/L, MPS showed strong antioxidant activity, with significant scavenging rates in various tests such as DPPH (57.0 ± 1.05 %) and ABTS (66.4 ± 2.48 %). MPS displayed 77 %, 80 %, and 43 % inhibition for α-amylase, α-glucosidase, and ACE-inhibition, respectively. MPS displayed significant antiproliferative effects, achieving 100 % and 99 % inhibition against Caco-2 and MCF-7 cells at 2500 mg/L, respectively. MPS showed broad-spectrum antibacterial properties against both Gram-positive and Gram-negative foodborne bacteria. Gemmiger formicilis, Blautia species, Collinsella aerofaciens, and Bifidobacterium longum showed strong positive correlations, suggesting increased SCFA production. Network analysis indicated species correlations, with 86 % showing negative correlations with Escherichia and Enterococcus saccharolyticus. MPS was abundant in Firmicutes, Actinobacteria, and Proteobacteria phyla. Date pomace could serve as a dietary fiber source, promoting better health.

Innate and adaptive immune-directed tumour microenvironment in pancreatic ductal adenocarcinoma

One of the most deadly and aggressive cancers in the world, pancreatic ductal adenocarcinoma (PDAC), typically manifests at an advanced stage. PDAC is becoming more common, and by the year 2030, it is expected to overtake lung cancer as the second greatest cause of cancer-related death. The poor prognosis can be attributed to a number of factors, including difficulties in early identification, a poor probability of curative radical resection, limited response to chemotherapy and radiotherapy, and its immunotherapy resistance. Furthermore, an extensive desmoplastic stroma that surrounds PDAC forms a mechanical barrier that prevents vascularization and promotes poor immune cell penetration. Phenotypic heterogeneity, drug resistance, and immunosuppressive tumor microenvironment are the main causes of PDAC aggressiveness. There is a complex and dynamic interaction between tumor cells in PDAC with stromal cells within the tumour immune microenvironment. The immune suppressive microenvironment that promotes PDAC aggressiveness is contributed by a range of cellular and humoral factors, which itself are modulated by the cancer. In this review, we describe the role of innate and adaptive immune cells, complex tumor microenvironment in PDAC, humoral factors, innate immune-mediated therapeutic advances, and recent clinical trials in PDAC.

Bioactive properties and untargeted metabolomics analysis of bioaccessible fractions of non-fermented and fermented date fruit pomace by novel yeast isolates

In this study, attempts were made to utilize date by-product (date fruit pomace; DFP). This study aimed to investigate the health-promoting benefits of the fermented and non-fermented DFP before in vitro digestion and after (bioaccessible fraction). Untargeted metabolomic analyses for bioaccessible fractions were performed by UPLC-QTOF. DPPH percentages were 89.7%-90.3%, 90.1%-91.3%, and 90.8%-91.3% in the control, I. orientalis, and P. kudriazevii samples, respectively, before digestion; α-glucosidase inhibition before digestion was 1.9%-24.4%, 16.3%-30.0%, and 21.3%-31.3%, respectively; antimicrobial activities were 6.1%-13.3%, 13.7%-25.7%, and 20.6%-28.0% against E. coli O157:H7 and 2.2%-11.9%, 7.2%-20.7%, and 11.9%-29.2% against L. monocytogenes, respectively. The DPPH scavenging percentages were ∼63% lower in the bioaccessible fraction. The differentially regulated metabolites classes were benzene and derivatives, amino acids, peptides and analogs, organic acids, and phenols. This study revealed that the fermented DFP exhibited higher health properties than control.

Lactic Acid Bacteria Isolated from Fresh Vegetable Products: Potential Probiotic and Postbiotic Characteristics Including Immunomodulatory Effects

The ability to perform effectively in the gastrointestinal tract (GIT) is one of the most significant criteria in the selection of potential probiotic bacteria. Thus, the present study aimed to investigate the potential probiotic characteristics of some selected lactic acid bacteria (LAB) isolated from vegetable products. Probiotic characteristics included tolerance to acid and bile, cholesterol-removing ability, bile salt hydrolysis, resistance against lysozyme and antibiotics, production of exopolysaccharides (EPS), antimicrobial and hemolytic activities, and cell surface characteristics (auto-aggregation, co-aggregation, and hydrophobicity). The survival rate of isolates after G120 ranged from 8.0 to 8.6 Log₁₀ CFU/mL. After the intestinal phase (IN-120), the bacterial count ranged from 7.3 to 8.5 Log₁₀ CFU/mL. The bile tolerance rates ranged from 17.8 to 51.1%, 33.6 to 63.9%, and 55.9 to 72.5% for cholic acid, oxgall, and taurocholic acid, respectively. Isolates F1, F8, F23, and F37 were able to reduce cholesterol (>30%) from the broth. The auto-aggregation average rate increased significantly after 24 h for all isolates, while two isolates showed the highest hydrophobicity values. Moreover, isolates had attachment capabilities comparable to those of HT-29 cells, with an average of 8.03 Log₁₀ CFU/mL after 2 h. All isolates were resistant to lysozyme and vancomycin, and 8 out of the 17 selected isolates displayed an ability to produce exopolysaccharides (EPS). Based on 16S rRNA sequencing, LAB isolates were identified as Enterococcus faecium, E. durans, E. lactis, and Pediococcus acidilactici.

Induction of anti-microbial immune responses in severely immunodeficient hosts by IFNγ-expressing Salmonella enterica serovar Typhimurium correlates with efficient activation of macrophage effectors (VAC8P.1050)

Susceptibility to infection by the intracellular bacterial pathogen, Salmonella enterica serovar Typhimurium (S. typhimurium), is controlled by many genes of innate and adaptive immunity. One of the most critical genes is IFN-γ and mice deficient in IFN-γ synthesis are highly susceptible to Salmonella. Previously, we also demonstrated that mice deficient in MyD88, an adaptor that regulates TLR signaling, are susceptible to Salmonella infection. In the current study, we compared immune responses in mice deficient in IFN-γ or MyD88 with wild-type controls following infection with an attenuated strain of S. typhimurium (designated BRD509) or a recombinant derivative engineered to express murine IFN-γ (GIDIFN). Infection studies with BRD509 or GIDIFN revealed that the latter strain was significantly less virulent in immunodeficient mice than BRD509 and correlated with decreased bacterial loads in systemic organs. Enhanced responsiveness was due to GIDIFN strain’s ability to activate effector macrophages, as shown by increased synthesis of inflammatory cytokines and anti-microbial effector molecules, including NO. Gene expression profiling by qPCR demonstrated stronger induction of key inflammatory modulators by GIDIFN in macrophages of immunodeficient animals. These findings suggest that immunotherapeutic approaches using attenuated bacterial strains expressing immunomodulatory genes is more efficacious and offers a superior safety profile even in severely immunodeficient hosts.

Cholinergic modulation of inflammatory diseases: role in the amelioration of type 1 diabetes (IRC4P.452)

The cholinergic anti-inflammatory pathway connects the central nervous system with the immune system via the vagus nerve and controls the release of pro-inflammatory cytokines. We have previously shown that inhibition of acetylcholinesterase (AChE), thereby leading to an accumulation of acetylcholine (ACh), modulates the inflammatory response. Type 1 diabetes (T1D) results from a deficiency in the production of insulin as a consequence of an immune-mediated damage of pancreatic β cells. Here, we investigated the potential of regulating the development of T1D through the inhibition of AChE. Modulation of AChE activity was achieved by administration of paraoxon, a potent inhibitor of the enzyme. To induce hyperglycemia, we used a well-characterized regimen of multiple low doses of streptozotocin (MLD-STZ). Our results showed that inhibition of AChE prevented the development of MLD-STZ-induced hyperglycemia (blood glucose levels >200 mg/dl) in C57BL/6 mice. At day 18 post-STZ administration, immunohistological analysis of pancreatic tissue in paraoxon pre-treated mice revealed healthy islets with normal levels of insulin. In contrast, control mice routinely exhibited glucose levels of 300-400 mg/dl and severe loss of islet morphology by the same time point. qRT-PCR analysis demonstrated that AChE inhibition prevents the loss of insulin production induced by MLD-STZ administration. Our results provide evidence for cholinergic control of the development of T1D in mice.

Systemic administration of metallic nanoparticles initiates an acute, NALP3-mediated, inflammatory response (169.8)

Nanoparticles are increasingly being commercialized for use in biomedicine. Given their inorganic metal makeup, nanoparticles have been thought to be biologically inert. However, there is accumulating evidence demonstrating that, due to their exceedingly small size, inorganic particles may have deleterious effects on pulmonary function. In this study, we investigated the potential immunotoxicity associated with systemic administration of composite inorganic nanoparticles. Using a murine model, the acute effect of intraperitoneal inoculation of metallic nanoparticles was studied by monitoring changes in hematological and inflammatory parameters as well as serum levels of organ toxicity indicators, including AST, ALT, LDH, BUN and creatinine. Our findings indicate that high dose systemic exposure is associated with acute liver injury due to preferential accumulation of nanoparticles in this organ. Moreover, injection of nanoparticles resulted in the activation of phagocytic cells and the secretion of proinflammatory cytokines. Utilizing several lines of gene-deficient animals, we demonstrate that the nanoparticle-triggered response is dependent on the NALP3 inflammasome. These findings suggest that nanoparticles may be subject to recognition by the innate immune system.

Orexin-1 receptor co-localizes with pancreatic hormones in islet cells and modulates the outcome of streptozotocin-induced diabetes mellitus

Recent studies have shown that orexins play a critical role in the regulation of sleep/wake states, feeding behaviour, and reward processes. The exocrine and endocrine pancreas are involved in the regulation of food metabolism and energy balance. This function is deranged in diabetes mellitus. This study examined the pattern of distribution of orexin-1 receptor (OX₁R) in the endocrine cells of the pancreas of normal and diabetic Wistar (a model of type 1 diabetes), Goto-Kakizaki (GK, a model of type 2 diabetes) rats and in orexin-deficient (OX^−/−) and wild type mice. Diabetes mellitus (DM) was induced in Wistar rats and mice by streptozotocin (STZ). At different time points (12 h, 24 h, 4 weeks, 8 months and 15 months) after the induction of DM, pancreatic fragments of normal and diabetic rats were processed for immunohistochemistry and Western blotting. OX₁R-immunoreactive nerves were observed in the pancreas of normal and diabetic Wistar rats. OX₁R was also discernible in the pancreatic islets of normal and diabetic Wistar and GK rats, and wild type mice. OX₁R co-localized with insulin (INS) and glucagon (GLU) in the pancreas of Wistar and GK rats. The number of OX₁R-positive cells in the islets increased markedly (p<0.0001) after the onset of DM. The increase in the number of OX₁R-positive cells is associated with a high degree of co-localization with GLU. The number of GLU- positive cells expressing OX₁R was significantly (p<0.0001) higher after the onset of DM. The tissue level of OX₁R protein increased with the duration of DM especially in type 1 diabetes where it co-localized with cleaved caspase 3 in islet cells. In comparison to STZ-treated wild type mice, STZ-treated OX^−/− animals exhibited reduced hyperglycemia and handled glucose more efficiently in glucose tolerance test. The findings suggest an important role for the OX-OX₁R pathway in STZ-induced experimental diabetes.

Prospective evaluation of mannan and anti-mannan antibodies for diagnosis of invasive Candida infections in patients with neutropenic fever

The diagnostic performance and usefulness of the Platelia antigen and antibody test (Bio-Rad) was investigated in a prospective study of haematological patients at risk for invasive Candida infections. Among 100 patients, 86 were eligible, of whom invasive candidiasis (IC) occurred in 12 (14%), according to the criteria of the European Organization for Research and Treatment of Cancer/Mycoses Study Group. These included candidaemia due to Candida albicans (one patient) or Candida tropicalis (four patients), and hepatosplenic candidiasis (seven patients). The comparator group of 74 patients included 50 with febrile neutropenia alone and 24 with mould infections. A strategy was developed to determine diagnostic cut-offs from receiver operating characteristic curves with maximal sensitivity and, given this sensitivity, maximal specificity, both being greater than 0. In this patient population, these values were 0.25 ng ml(-1) for mannan (M) and 2.6 arbitrary units ml(-1) for anti-mannan (AM), which are lower than those recommended by the manufacturer. All patients developed at least one positive diagnostic M or AM result during the 10 days of persistent febrile neutropenia (PFN). The optimal overall performance was found when two consecutive positive tests for both M and AM were used [sensitivity, specificity, positive predictive value and negative predictive value (NPV) (95 % confidence intervals) of 0.73 (0.39-0.94), 0.80 (0.69-0.89), 0.36 (0.17-0.59) and 0.95 (0.86-0.99), respectively]. There was a positive correlation of M with beta-D-glucan (r=0.28, P=0.01). The first positive M test was found up to a mean+/-sd of 8.8+/-8.5 (range 2-23) days prior to a clinical/mycological diagnosis of IC. Day-to-day variation in quantitative M levels was high. High-level AM responses were delayed until leucopenia resolved. The low specificities of the test performance may have been due to some of the comparator patients having subclinical Candida infections as evidenced by the high incidence of colonization among them (60% had a colonization index of >or=0.5). The high NPVs suggest that the tests may be particularly useful in excluding IC. It is feasible to explore the use of serial measurements of M and AM as part of a broader diagnostic strategy for selecting PFN patients to receive antifungal drug therapy.

Iosimenol, a new non-ionic dimeric contrast medium, does not induce immunoreactivity in the popliteal lymph node assay

Animal studies in mice were conducted to determine the potential immunoreactivity of the new non-ionic dimeric contrast medium (CM) iosimenol using the PLNA and flow cytometric analyses. Comparative studies were performed with iodixanol. The known immune-reactive substance strepozotocin (STZ) and vehicle injections served as positive and negative controls, respectively. Our experiments did not show any immunological effect of iosimenol, concluding that the new CM iosimenol may be beneficial for use in high-risk patients.

Invasive fungal infections are associated with severe depletion of circulating RANTES

Serum RANTES (regulated on activation, normal T-cell expressed and secreted) concentrations were measured in 14 patients who had haematological malignancies and developed invasive fungal infections (three of them definite, eight probable and three possible). RANTES levels fell substantially from pre-chemotherapy values at the start of and throughout the fungal infection, and recovered in patients who survived the fungal infection. However, in patients who died from the invasive fungal infection, RANTES levels did not recover. For survivors the mean ± sd levels for RANTES were 7656 ± 877 pg ml−1 on the day prior to chemotherapy, 3723 ± 2443 pg ml−1 on the first day of fungal infection diagnosis (significantly different from baseline; P = 0.001) and 9078 ± 2256 pg ml−1 at recovery from the fungal infection (significantly different from lowest value; P < 0.0001). Platelet counts were closely correlated with the RANTES levels (r = 0.63, P < 0.001). The RANTES concentrations for the three patients who died were similar to those who survived at all equivalent timepoints, but were significantly lower at the time of death (792 ± 877) compared to the values at recovery for survivors (P = 0.005). The finding that patients who died from an invasive fungal infection had very low platelet counts and RANTES concentrations suggests that these could play a role in host response to such infections.