Colon hypersensitivity to distension, rather than excessive gas production, produces carbohydrate-related symptoms in individuals with irritable bowel syndrome

Background & Aims: Poorly digested, fermentable carbohydrates may induce symptoms of irritable bowel syndrome (IBS), via unclear mechanisms. We performed a randomized trial with magnetic resonance imaging (MRI) analysis to investigate correlations between symptoms and changes in small and large bowel contents following oral challenge. Methods: We performed a 3-period crossover study of 29 adult patients with IBS (based on Rome III criteria, with symptoms of abdominal pain or discomfort for at least 2 days/week) and reported bloating. In parallel we performed the same study of 29 healthy individuals (controls). Studies were performed in the United Kingdom from January 2013 through February 2015. On 3 separate occasions (at least 7 days apart), subjects were given a 500 ml drink containing 40 g of carbohydrate (glucose in the first period, fructose in the second, and inulin in the third, in a random order). Levels of breath hydrogen were measured and intestinal content was assessed by MRI before and at various time points after consumption of each drink. Symptoms were determined based on subjects’ responses to the Hospital Anxiety and Depression Scale questionnaire and the Patient Health Questionnaire-15. The primary endpoint was whether participants had a clinically important symptom response during the 300 minutes following consumption of the drink. Results: More patients with IBS reached the pre-defined symptom threshold after intake of inulin (13/29) or fructose (11/29) than glucose (6/29). Symptoms peaked sooner after intake of fructose than inulin. Fructose increased small bowel water content in both patients and controls whereas inulin increased colonic volume and gas in both. Fructose and inulin increased breath hydrogen levels in both groups, compared to glucose; fructose produced an earlier increase than inulin. Controls had lower symptom scores during the period after drink consumption than patients with IBS, despite similar MRI parameters and breath hydrogen responses. In patients who reached the symptom threshold after inulin intake, peak symptom intensity correlated with peak colonic gas (r = 0.57; P<0.05). Changes in MRI features and peak breath hydrogen levels were similar in patients who did and did not reach symptom threshold. Conclusions: Patients with IBS and healthy individuals without IBS (controls) have similar physiological responses following intake of fructose or inulin; patients more frequently report symptoms after inulin than controls. In patients with a response to inulin, symptoms relate to levels of intra-luminal gas, but peak gas levels do not differ significantly between responders, non-responders or controls. This indicates that colonic hypersensitivity to distension, rather than excessive gas production, produces carbohydrate-related symptoms in patients with IBS. Clinicaltrials.gov no: NCT0177685

The KELT Follow-Up Network And Transit False-Positive Catalog: Pre-Vetted False Positives For TESS

The Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey of transiting planets orbiting bright stars for over 10 years. The KELT images have a pixel scale of ~23\u27\u27 pixel⁻¹—very similar to that of NASA\u27s Transiting Exoplanet Survey Satellite (TESS)—as well as a large point-spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3\u27. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with spatial resolution, cadence, and photometric precision higher than the KELT telescopes, as well as spectroscopic observations of the candidate host stars. The KELT-FUN team has followed-up over 1600 planet candidates since 2011, resulting in more than 20 planet discoveries. Excluding ~450 false alarms of non-astrophysical origin (i.e., instrumental noise or systematics), we present an all-sky catalog of the 1128 bright stars (6 \u3c V \u3c 13) that show transit-like features in the KELT light curves, but which were subsequently determined to be astrophysical false positives (FPs) after photometric and/or spectroscopic follow-up observations. The KELT-FUN team continues to pursue KELT and other planet candidates and will eventually follow up certain classes of TESS candidates. The KELT FP catalog will help minimize the duplication of follow-up observations by current and future transit surveys such as TESS

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Endocrine impact of Helicobacter pylori: Focus on ghrelin and ghrelin o-acyltransferase

Ghrelin is predominantly produced by the gastric enteroendocrine cell compartment and is octanoylated by the recently discovered ghrelin o-acyltransferase (GOAT) before secretion into the bloodstream. This octanoylation is essential for many of the biological properties of ghrelin including appetite stimulation and anti-inflammatory properties as only the acylated form of ghrelin binds to the ghrelin receptor, the growth hormone secretagogue receptor (GHS-R). Given the gastric location of ghrelin production, it is perhaps not surprising that insult to the gastric mucosa affects circulating ghrelin levels in humans. Helicobacter pylori (H. pylori) infects more than fifty percent of the world’s population and once established within the gastric mucosa, can persist for life. Infection is associated with chronic gastritis, gastric atrophy and ulceration, reduced appetite and a lower body mass index (BMI). The large majority of studies investigating levels of circulating ghrelin and ghrelin expression in the stomach in patients with H. pylori infection indicate that the bacterium has a negative impact on ghrelin production and/or secretion. Eradication of infection restores ghrelin, improves appetite and increases BMI in some studies, however, a causative relationship between H. pylori-associated serum ghrelin decline and food intake and obesity has not been established. Most studies measure total ghrelin in the circulation although the measurement of the ratio of acyl/total ghrelin gives a clearer indication that the ghrelin acylation process is altered during infection and atrophy. GOAT is essential for the production of biologically-active, acyl ghrelin and the impact of H. pylori on GOAT expression and activity will be highly informative in the future

The mitochondrial genome of the black-tailed dusky antechinus (Antechinus arktos)

In this study, we report the mitochondrial genome of the black-tailed antechinus (Antechinus arktos), a recently-discovered, endangered carnivorous marsupial inhabiting a caldera that straddles the border of Australia’s mid-east coast. The circular A. arktos genome is 17,334 bp in length and has an AT content of 63.3%. Its gene content and arrangement are consistent with reported marsupial mitogenome assemblies.</p

Ghrelin O-acyltransferase (GOAT) is expressed in prostate cancer tissues and cell lines and expression is differentially regulated in vitro by ghrelin

Background: Ghrelin is a 28 amino acid peptide hormone that is expressed in the stomach and a range of peripheral tissues, where it frequently acts as an autocrine/paracrine growth factor. Ghrelin is modified by a unique acylation required for it to activate its cognate receptor, the growth hormone secretagogue receptor (GHSR), which mediates many of the actions of ghrelin. Recently, the enzyme responsible for adding the fatty acid residue (octanoyl/acyl group) to the third amino acid of ghrelin, GOAT (ghrelin O-acyltransferase), was identified

Silencing of ghrelin receptor expression inhibits endometrial cancer cell growth in vitro and in vivo

Ghrelin is a 28-amino acid peptide hormone produced predominantly in the stomach but also in a range of normal cell types and tumors, where it has endocrine, paracrine, and autocrine roles. Previously, we have demonstrated that ghrelin has proliferative and antiapoptotic effects in endometrial cancer cell lines, suggesting a potential role in promoting tumor growth. In the present study, we investigated the effect of ghrelin receptor, GHSR, and gene silencing in vitro and in vivo and characterized ghrelin and GHSR1a protein expression in human endometrial tumors. GHSR gene silencing was achieved in the Ishikawa and KLE endometrial cancer cell lines, using a lentiviral short-hairpin RNA targeting GHSR. The effects of GHSR1a knockdown were further analyzed in vivo using the Ishikawa cell line in a NOD/SCID xenograft model. Cell proliferation was reduced in cultured GHSR1a knockdown Ishikawa and KLE cells compared with scrambled controls in the absence of exogenously applied ghrelin and in response to exogenous ghrelin (1,000 nM). The tumor volumes were reduced significantly in GHSR1a knockdown Ishikawa mouse xenograft tumors compared with scrambled control tumours. Using immunohistochemistry, we demonstrated that ghrelin and GHSR1a are expressed in benign and cancerous glands in human endometrial tissue specimens, although there was no correlation between the intensity of staining and cancer grade. These data indicate that downregulation of GHSR expression significantly inhibits endometrial cancer cell line and mouse xenograft tumour growth. This is the first preclinical evidence that downregulation of GHSR may be therapeutic in endometrial cancer

Turtle ghrelin [Correspondence]

In a recent paper, Wang and colleagues described the genomes of two turtles, the Chinese soft-shell turtle (Pelodiscus sinensis) and the green sea turtle (Chelonia mydas)1. A salient finding was an apparent absence of GHRL, the gene encoding the only known circulating orexigen, the peptide hormone ghrelin. The highly conserved GHRL encodes at least two bioactive peptide hormones, ghrelin2 and obestatin3, which are recognized to have a diverse range of functions in a number of cell types and physiological systems4, 5. Wang and colleagues hypothesized that the absence of ghrelin was associated with the low metabolic rate observed in these turtle species1

No effect of administration of unacylated ghrelin on subcutaneous PC3 xenograft growth in a Rag1−/− mouse model of metabolic dysfunction

Ghrelin is a peptide hormone which, when acylated, regulates appetite, energy balance and a range of other biological processes. Ghrelin predominately circulates in its unacylated form (unacylated ghrelin; UAG). UAG has a number of functions independent of acylated ghrelin, including modulation of metabolic parameters and cancer progression. UAG has also been postulated to antagonise some of the metabolic effects of acyl-ghrelin, including its effects on glucose and insulin regulation. In this study, Rag1-/- mice with high-fat diet-induced obesity and hyperinsulinaemia were subcutaneously implanted with PC3 prostate cancer xenografts to investigate the effect of UAG treatment on metabolic parameters and xenograft growth. Daily intraperitoneal injection of 100 μg/kg UAG had no effect on xenograft tumour growth in mice fed normal rodent chow or 23% high-fat diet. UAG significantly improved glucose tolerance in host Rag1-/- mice on a high-fat diet, but did not significantly improve other metabolic parameters. We propose that UAG is not likely to be an effective treatment for prostate cancer, with or without associated metabolic syndrome

Modelling the tumor immune microenvironment for precision immunotherapy

The complexity of the cellular and acellular players within thetumor microenvironment (TME) allows for significant variation inTME constitution and role in anticancer treatment response. Spatialalterations in populations of tumor cells and adjacent non-malignant cells, including endothelial cells, fibroblasts and tissue-infiltrating immune cells, often have a major role in determiningdisease progression and treatment response in cancer. Many currentstandard systemic antineoplastic treatments target the cancer cellsand could be further refined to directly target commonlydysregulated cell populations of the TME. Recent developments inimmuno-oncology and bioengineering have created an attractivepotential to model these complexities at the level of the individualpatient. These developments, along with the increasing momentum in precision medicine research and application, have catalysed exciting new discoveries in understanding drug–TME interactions, target identification, and improved efficacy of therapies. While rapid progress has been made, there are still many challenges to overcome in the development of accurate in vitro, in vivo and ex vivo models incorporating the cellular interactions that take place in the TME. In this review, we describe how advances in immuno-oncology and patient-derived models, such as patient-derived organoids and explant cultures, have enhanced the landscape of personalised immunotherapy prediction and treatment of solid organ malignancies. We describe and compare different immunological targets and perspectives on two-dimensional and three-dimensional modelling approaches that may be used to better rationalise immunotherapy use, ultimately providing a knowledge base for the integration of the autologous TME into these predictive models