scholarly journals The colon microcosm: a novel in vitro model to study Candida albicans colonisation of the human colon

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Megan Lenardon

Candida albicans colonises the gastro-intestinal (GI) tract of over 60% of the population. In severely ill or immune compromised patients, this fungus can escape the gut, disseminate through the body and cause systemic disease. Most research in the field has focused on defining traits that contribute directly to virulence; there are comparatively few studies which have addressed how C. albicans colonises and persists in the gut. Furthermore, such studies have typically been performed mouse models devoid of resident GI bacteria, completely neglecting the major impact of the local microbiota on GI colonisation. How, then, does C. albicans persist in the GI tract in the presence of the normal gut microbiota? To address this question, a novel in vitro two-phase anaerobic fermentation system that simulates the human colon microenvironment has been developed. This “colon microcosm” supports the growth of human faecal microbiota in liquid anaerobic colon medium (phase 1) and C. albicans growth on agar plugs which are added to the medium to mimic the epithelial surface (phase 2). The impact of C. albicans upon the faecal microbiota is monitored by examining the planktonic phase (phase 1), whilst the effect of the microbiota on the growth of C. albicans is monitored after extracting C. albicans cells from the agar plugs (phase 2). The results of assays carried out to validate the model will be presented, as will data from pilot studies which illustrate the potentially exploitable impact of the human GI microbiota from healthy individuals on C. albicans growth.

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A737-A737
Author(s):  
Loise Francisco-Anderson ◽  
Loise Francisco-Anderson ◽  
Mary Abdou ◽  
Michael Goldberg ◽  
Erin Troy ◽  
...  

BackgroundThe small intestinal axis (SINTAX) is a network of anatomic and functional connections between the small intestine and the rest of the body. It acts as an immunosurveillance system, integrating signals from the environment that affect physiological processes throughout the body. The impact of events in the gut in the control of tumor immunity is beginning to be appreciated. We have previously shown that an orally delivered single strain of commensal bacteria induces anti-tumor immunity preclinically via pattern recognition receptor-mediated activation of innate and adaptive immunity. Some bacteria produce extracellular vesicles (EVs) that share molecular content with the parent bacterium in a particle that is roughly 1/1000th the volume in a non-replicating form. We report here an orally-delivered and gut-restricted bacterial EV which potently attenuates tumor growth to a greater extent than whole bacteria or checkpoint inhibition.MethodsEDP1908 is a preparation of extracellular vesicles produced by a gram-stain negative strain of bacterium of the Oscillospiraceae family isolated from a human donor. EDP1908 was selected for its immunostimulatory profile in a screen of EVs from a range of distinct microbial strains. Its mechanism of action was determined by ex vivo analysis of the tumor microenvironment (TME) and by in vitro functional studies with murine and human cells.ResultsOral treatment of tumor-bearing mice with EDP1908 shows superior control of tumor growth compared to checkpoint inhibition (anti-PD-1) or an intact microbe. EDP1908 significantly increased the percentage of IFNγ and TNF producing CD8+ CTLs, NK cells, NKT cells and CD4+ cells in the tumor microenvironment (TME). EDP1908 also increased tumor-infiltrating dendritic cells (DC1 and DC2). Analysis of cytokines in the TME showed significant increases in IP-10 and IFNg production in mice treated with EDP1908, creating an environment conducive to the recruitment and activation of anti-tumor lymphocytes.ConclusionsThis is the first report of striking anti-tumor effects of an orally delivered microbial extracellular vesicle. These data point to oral EVs as a new class of immunotherapeutic drugs. They are particularly effective at harnessing the biology of the small intestinal axis, acting locally on host cells in the gut to control distal immune responses within the TME. EDP1908 is in preclinical development for the treatment of cancer.Ethics ApprovalPreclinical murine studies were conducted under the approval of the Avastus Preclinical Services’ Ethics Board. Human in vitro samples were attained by approval of the IntegReview Ethics Board; informed consent was obtained from all subjects.


2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Joao Gabriel Rosa Ramos ◽  
Sandra Cristina Hernandes ◽  
Talita Teles Teixeira Pereira ◽  
Shana Oliveira ◽  
Denis de Melo Soares ◽  
...  

Abstract Background Clinical pharmacists have an important role in the intensive care unit (ICU) team but are scarce resources. Our aim was to evaluate the impact of on-site pharmacists on medical prescriptions in the ICU. Methods This is a retrospective, quasi-experimental, controlled before-after study in two ICUs. Interventions by pharmacists were evaluated in phase 1 (February to November 2016) and phase 2 (February to May 2017) in ICU A (intervention) and ICU B (control). In phase 1, both ICUs had a telepharmacy service in which medical prescriptions were evaluated and interventions were made remotely. In phase 2, an on-site pharmacist was implemented in ICU A, but not in ICU B. We compared the number of interventions that were accepted in phase 1 versus phase 2. Results During the study period, 8797/9603 (91.6%) prescriptions were evaluated, and 935 (10.6%) needed intervention. In phase 2, there was an increase in the proportion of interventions that were accepted by the physician in comparison to phase 1 (93.9% versus 76.8%, P < 0.001) in ICU A, but there was no change in ICU B (75.2% versus 73.9%, P = 0.845). Conclusion An on-site pharmacist in the ICU was associated with an increase in the proportion of interventions that were accepted by physicians.


2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii46-ii46
Author(s):  
Andrew Lassman ◽  
Patrick Wen ◽  
Martin van den Bent ◽  
Scott Plotkin ◽  
Annemiek Walenkamp ◽  
...  

Abstract BACKGROUND Selinexor is an FDA-approved first-in-class, oral selective nuclear export inhibitor which forces nuclear retention of many tumor suppressor proteins. METHODS We conducted a phase 2 trial of selinexor monotherapy for adults with recurrent GBM including a surgical arm to explore intratumoral PK and 3 medical arms to optimize dosing. Prior treatment with radiotherapy and temozolomide was required; prior bevacizumab was exclusionary. The primary endpoint was 6-month progression-free survival (6mPFS) rate. RESULTS Selinexor administered ~2 hours pre-operatively yieleded average intratumoral concentration (136 nM, n=6) comparable to the in vitro IC50 (130 nM) from 7 primary human GBM cell lines. Among all 68 patients accrued to 3 medical arms (~85 mg BIW, n=24; 60 mg BIW, n=14; 80 mg QW, n=30), median age was 56 years (21–78). Median number of prior lines of therapies was 2 (1–7). At 80 mg QW, 28% patients were progression-free at the end of cycle 6; the 6mPFS was 17%; disese control rate by RANO was 37% (1 CR, 2 PRs, 7 SD) among 27 evaluable patients; responses were durable (median 11.1 months), and treatment lasted for 442, 547 and 1282 days in 3 responders, as of data lock, with one responder remaining on treatment off study; median overall survival was 10.2 months with 95% CI (7.0, 15.4). The ~85 mg BIW-schedule was abandoned due to poor tolerability. The related adverse events (all grades) in patients on ~85 mg BIW/60 mg BIW/80 mg QW were nausea (41.7%/64.3%/66.7%), fatigue (70.8%/71.4%/50.0%), neutropenia (29.2%/14.3%/33.3%), decreased appetite (45.8%/71.4%/26.7%), thrombocytopenia (66.7%/28.6%/23.3%) and weight loss (16.7%,/42.9%/6.7%). CONCLUSION Selinexor monotherapy demonstrated encouraging intratumoral penetration and efficacy, with durable disease control in rGBM. Monotherapy dose at 80 mg QW is recommended for further development in rGBM. A phase 1/2 study of combination therapy for newly diagnosed or rGBM has been initiated (NCT04421378).


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 446-447
Author(s):  
Natasha L Bell ◽  
Daisy A Gonzalez ◽  
Kendrah DeLeon

Abstract The effect of electrolyzed reduced water consumption by cattle is not well defined. The objective of this study was to evaluate the effect of electrolyzed reduced water on intake, in vitro true digestibility (IVTD), ORP and pH in four ruminally cannulated steers (4 Bos taurus; 317 kg BW). Steers were subjected to a two period (14 d), two treatment crossover design. Treatment included: 1) standard water (CON; pH = 7.0 ± 1.0) or 2) electrolyzed reduced water (ERW; pH = 9.0 ± 1.0). The project comprised of two studies where the effects of ERW were observed for steers consuming a roughage diet (phase 1) or concentrate diet (phase 2). During Phase 1, animals were provided bermudagrass hay ad libitum. A 14 d transition period followed phase 1 to allow transition of diets. In phase 2, animals were maintained on a concentrate diet. During each period, d 1–8 served as a treatment adaptation phase, d 9–13 allowed for measures of intake and digestion, and rumen fluid was collected at h 0, 2, 4, 8, and 12 after feeding on d 14 for VFA, pH and ORP analysis. Data were analyzed using the MIXED procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC). Intake, digestion, and ruminal fermentation parameters were not different for CON vs ERW steers (P ≥ 0.06). Analysis of VFA data have not been finalized and will be reported later. Results indicate that ERW has no effect on intake, digestion or ruminal fermentation parameters of steers consuming roughage or concentrate diets.


2020 ◽  
Vol 11 (5) ◽  
pp. 489-509
Author(s):  
R. Cheng ◽  
H. Liang ◽  
Y. Zhang ◽  
J. Guo ◽  
Z. Miao ◽  
...  

This study aimed to determine the impact of Lactobacillus plantarum PC170 concurrent with antibiotic treatment and/or during the recovery phase after antibiotic treatment on the body weight, faecal bacterial composition, short-chain fatty acids (SCFAs) concentration, and splenic cytokine mRNA expression of mice. Orally administrated ceftriaxone quantitatively and significantly decreased body weight, faecal total bacteria, Akkermansia muciniphila, and Lactobacillus plantarum, and faecal SCFAs concentration. Ceftriaxone treatment also dramatically altered the faecal microbiota with an increased Chao1 index, decreased species diversities and Bacteroidetes, and more Firmicutes and Proteobacteria. After ceftriaxone intervention, these changes all gradually started to recover. However, faecal microbiota diversities were still totally different from control by significantly increased α- and β-diversities. Bacteroidetes all flourished and became dominant during the recovery process. However, mice treated with PC170 both in parallel with and after ceftriaxone treatment encouraged more Bacteroidetes, Verrucomicrobia, and Actinobacteria, and the diversity by which to make faecal microbiota was very much closer to control. Furthermore, the expression of splenic pro-inflammatory cytokine tumour necrosis factor-α mRNA in mice supplemented with PC170 during the recovery phase was significantly lower than natural recovery. These results indicated that antibiotics, such as ceftriaxone, even with short-term intervention, could dramatically damage the structure of gut microbiota and their abilities to produce SCFAs with loss of body weight. Although such damages could be partly recovered with the cessation of antibiotics, the implication of antibiotics to gut microbiota might remain even after antibiotic treatment. The selected strain PC170 might be a potential probiotic because of its contributions in helping the host animal to remodel or stabilise its gut microbiome and enhancing the anti-inflammatory response as protection from the side effects of antibiotic therapy when it was administered in parallel with and after antibiotic treatment.


2014 ◽  
Vol 2 (1) ◽  
pp. 1-124 ◽  
Author(s):  
Caroline L Watkins ◽  
Stephanie P Jones ◽  
Michael J Leathley ◽  
Gary A Ford ◽  
Tom Quinn ◽  
...  

BackgroundRapid access to emergency stroke care can reduce death and disability by enabling immediate provision of interventions such as thrombolysis, physiological monitoring and stabilisation. One of the ways that access to services can be facilitated is through emergency medical service (EMS) dispatchers. The sensitivity of EMS dispatchers for identifying stroke is < 50%. Studies have shown that activation of the EMSs is the single most important factor in the rapid triage and treatment of acute stroke patients.ObjectivesTo facilitate recognition of stroke by emergency medical dispatchers (EMDs).DesignAn eight-phase mixed-methods study. Phase 1: a retrospective cohort study exploring stroke diagnosis. Phase 2: semi-structured interviews exploring public and EMS interactions. Phases 3 and 4: a content analysis of 999 calls exploring the interaction between the public and EMDs. Phases 5–7: development and implementation of stroke-specific online training (based on phases 1–4). Phase 8: an interrupted time series exploring the impact of the online training.SettingOne ambulance service and four hospitals.ParticipantsPatients arriving at hospital by ambulance with stroke suspected somewhere on the stroke pathway (phases 1 and 8). Patients arriving at hospital by ambulance with a final diagnosis of stroke (phase 2). Calls to the EMSs relating to phase 1 patients (phases 3 and 4). EMDs (phase 7).InterventionsStroke-specific online training package, designed to improve recognition of stroke for EMDs.Main outcome measuresPhase 1: symptoms indicative of a final and dispatch diagnosis of stroke. Phase 2: factors involved in the decision to call the EMSs when stroke is suspected. Phases 3 and 4: keywords used by the public when describing stroke and non-stroke symptoms to EMDs. Phase 8: proportion of patients with a final diagnosis of stroke correctly dispatched as stroke by EMDs.ResultsPhase 1: for patients with a final diagnosis of stroke, facial weakness and speech problems were significantly associated with an EMD code of stroke. Phase 2: four factors were identified – perceived seriousness; seeking and receiving lay or professional advice; caller’s description of symptoms and emotional response to symptoms. Phases 3 and 4: mention of ‘stroke’ or one or more Face Arm Speech Test (FAST) items is much more common in stroke compared with non-stroke calls. Consciousness level was often difficult for callers to determine and/or communicate. Phase 8: there was a significant difference (p = 0.003) in proportions correctly dispatched as stroke – before the training was implemented 58 out of 92 (63%); during implementation of training 42 out of 48 (88%); and after training implemented 47 out of 59 (80%).ConclusionsEMDs should be aware that callers are likely to describe loss of function (e.g. unable to grip) rather than symptoms (e.g. weakness) and that callers using the word ‘stroke’ or describing facial weakness, limb weakness or speech problems are likely to be calling about a stroke. Ambiguities and contradictions in dialogue about consciousness level arise during ambulance calls for suspected and confirmed stroke. The online training package improved recognition of stroke by EMDs. Recommendations for future research include testing the effectiveness of the Emergency Stroke Calls: Obtaining Rapid Telephone Triage (ESCORTT) training package on the recognition of stroke across other EMSs in England; and exploring the impact of the early identification of stroke by call handlers on patient and process outcomes.FundingThe National Institute for Health Research Programme Grants for Applied Research programme.


2001 ◽  
Vol 45 (2) ◽  
pp. 485-494 ◽  
Author(s):  
Arnold Louie ◽  
Pamela Kaw ◽  
Partha Banerjee ◽  
Weiguo Liu ◽  
George Chen ◽  
...  

ABSTRACT In vitro time-kill studies and a rabbit model of endocarditis and pyelonephritis were used to define the impact that the order of exposure of Candida albicans to fluconazole (FLC) and amphotericin B (AMB), as sequential and combination therapies, had on the susceptibility of C. albicans to AMB and on the outcome. The contribution of FLC-induced resistance to AMB for C. albicans also was assessed. In vitro, AMB monotherapy rapidly killed each of four C. albicans strains; FLC alone was fungistatic. Preincubation of these fungi with FLC for 18 h prior to exposure to AMB decreased their susceptibilities to AMB for 8 to >40 h. Induced resistance to AMB was transient, but the duration of resistance increased with the length of FLC preincubation. Yeast sequentially incubated with FLC followed by AMB plus FLC (FLC→AMB+FLC) showed fungistatic growth kinetics similar to that of fungi that were exposed to FLC alone. This antagonistic effect persisted for at least 24 h. Simultaneous exposure of C. albicans to AMB and FLC [AMB+FLC(simult)] demonstrated activity similar to that with AMB alone for AMB concentrations of ≥1 μg/ml; antagonism was seen using an AMB concentration of 0.5 μg/ml. The in vitro findings accurately predicted outcomes in our rabbit infection model. In vivo, AMB monotherapy and treatment with AMB for 24 h followed by AMB plus FLC (AMB→AMB+FLC) rapidly sterilized kidneys and cardiac vegetations. AMB+FLC(simult) and FLC→AMB treatments were slower in clearing fungi from infected tissues. FLC monotherapy and FLC→AMB+FLC were both fungistatic and were the least active regimens. No adverse interaction was observed between AMB and FLC for the AMB→FLC regimen. However, FLC→AMB treatment was slower than AMB alone in clearing fungi from tissues. Thus, our in vitro and in vivo studies both demonstrate that preexposure of C. albicans to FLC reduces fungal susceptibility to AMB. The length of FLC preexposure and whether AMB is subsequently used alone or in combination with FLC determine the duration of induced resistance to AMB.


Author(s):  
Benjamin W. Scandling ◽  
Jia Gou ◽  
Jessica Thomas ◽  
Jacqueline Xuan ◽  
Chuan Xue ◽  
...  

Many cells in the body experience cyclic mechanical loading, which can impact cellular processes and morphology. In vitro studies often report that cells reorient in response to cyclic stretch of their substrate. To explore cellular mechanisms involved in this reorientation, a computational model was developed by utilizing the previous computational models of the actin-myosin-integrin motor-clutch system developed by others. The computational model predicts that under most conditions, actin bundles align perpendicular to the direction of applied cyclic stretch, but under specific conditions, such as low substrate stiffness, actin bundles align parallel to the direction of stretch. The model also predicts that stretch frequency impacts the rate of reorientation, and that proper myosin function is critical in the reorientation response. These computational predictions are consistent with reports from the literature and new experimental results presented here. The model suggests that the impact of different stretching conditions (stretch type, amplitude, frequency, substrate stiffness, etc.) on the direction of cell alignment can largely be understood by considering their impact on cell-substrate detachment events, specifically whether detachment occurs during stretching or relaxing of the substrate.


Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1601 ◽  
Author(s):  
Hiroki Saito ◽  
Yu Toyoda ◽  
Tappei Takada ◽  
Hiroshi Hirata ◽  
Ami Ota-Kontani ◽  
...  

The beneficial effects of fatty acids (FAs) on human health have attracted widespread interest. However, little is known about the impact of FAs on the handling of urate, the end-product of human purine metabolism, in the body. Increased serum urate levels occur in hyperuricemia, a disease that can lead to gout. In humans, urate filtered by the glomerulus of the kidney is majorly re-absorbed from primary urine into the blood via the urate transporter 1 (URAT1)-mediated pathway. URAT1 inhibition, thus, contributes to decreasing serum urate concentration by increasing net renal urate excretion. Here, we investigated the URAT1-inhibitory effects of 25 FAs that are commonly contained in foods or produced in the body. For this purpose, we conducted an in vitro transport assay using cells transiently expressing URAT1. Our results showed that unsaturated FAs, especially long-chain unsaturated FAs, inhibited URAT1 more strongly than saturated FAs. Among the tested unsaturated FAs, eicosapentaenoic acid, α-linolenic acid, and docosahexaenoic acid exhibited substantial URAT1-inhibitory activities, with half maximal inhibitory concentration values of 6.0, 14.2, and 15.2 μM, respectively. Although further studies are required to investigate whether the ω-3 polyunsaturated FAs can be employed as uricosuric agents, our findings further confirm FAs as nutritionally important substances influencing human health.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 81-81
Author(s):  
Alini Veira ◽  
Luan S Santos ◽  
Alicia Fraga ◽  
Paulo Campos ◽  
Raphael Caetano ◽  
...  

Abstract Recent studies have shown that feed intake, nutrient metabolism and utilization may vary during the 24-h circadian period. In this regard, this study aimed at evaluating the impact on performance from the switching of conventional to sequential feeding programs with diets that differ in amino acid content over the day for growing–finishing pigs. Sixty-eight 25-kg (±2.04) BW barrows were assigned to 4 feeding programs (17 animals per treatment): 1) conventional feeding (CONV), in which pigs received 100% of standardized ileal digestible (SID) AA recommendations for the entire day; 2) sequential feeding (SEQ80-120), providing 80% SID AA recommendations from 2400 to 1159 h and 120% from 1200 to 2359 h; 3) sequential feeding (SEQ70-130) providing 70% SID AA recommendations from 2400 to 1159 h and 130% from 1200 to 2359 h; and 4) sequential feeding (SEQ60-140) providing 60% SID AA recommendations from 2400 to 1159 h and 140% from 1200 to 2359 h. The experimental period lasted 82 d and was subdivided in 3 phases: phase 1 (0 to 28 d), phase 2 (29 to 54 d) and phase 3 (55 to 82 d). The data were analyzed using the MIXED procedure in SAS (SAS Inst. Inc., Cary, NC). SEQ80-120 and SEQ60-140 did not improve performance compared to CONV (P &gt; 0.05). However, ADFI, ADG and BW was higher for SEQ70-130 than CONV during phase 1 (1.49 vs 1.3 kg/d; 0.74 vs 0.65 kg/d; 46.55 vs 43.40 kg, respectively; P &lt; 0.05). During phase 2, BW tended to be higher for SEQ70-130 than CONV (69.20 vs 63.60 kg; P = 0.08). In the entire experimental period, ADFI tended to be higher for SEQ70-130 than CONV (2.08 vs 1.89 kg/d; P = 0.10). According to our results, sequential feeding program improves performance of growing–finishing at the beginning of the period.


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