TRAV26-2 T-Cell Receptor Expression Is Associated With Mucosal Lymphocyte Response to Wheat Proteins in Patients With Functional Dyspepsia

INTRODUCTION

An association between functional dyspepsia (FD) and wheat-containing foods has been reported in observational studies; however, an adaptive response has not been demonstrated. We examined whether antigens present in wheat could provoke a response from FD duodenal lymphocytes.

METHODS

Lamina propria mononuclear cells (LPMCs) were isolated from duodenal biopsies from 50 patients with FD and 23 controls. LPMCs were exposed to gluten (0.2 mg/mL) or gliadin (0.2 mg/mL) for 24 hours. Flow cytometry was performed to phenotype lymphocytes. Quantitative PCR was used to measure the expression of gliadin-associated T-cell receptor alpha variant ( TRAV ) 26-2.

RESULTS

In response to gliadin (but not gluten) stimulation, the effector Th2-like population was increased in FD LPMCs compared with that in controls and unstimulated FD LPMCs. Duodenal gene expression of TRAV26- 2 was decreased in patients with FD compared with that in controls. We identified a positive association between gene expression of this T-cell receptor variant and LPMC effector Th17-like cell populations in patients with FD, but not controls after exposure to gluten, but not gliadin.

DISCUSSION

Our findings suggest that gliadin exposure provokes a duodenal effector Th2-like response in patients with FD, supporting the notion that food antigens drive responses in some patients. Furthermore, these findings suggest that altered lymphocyte responses to wheat proteins play a role in FD pathogenesis.

Salt-Taste Polymorphism TRPV1-rs8065080 Is Associated with Increased Likelihood of Depression in an Elderly Cohort

INTRODUCTION

Despite the prevalence of depression and anxiety worldwide, their aetiologies remain unclear, and they can be difficult to diagnose and treat. Changes in salt-taste perception have been found in both conditions. Single-nucleotide polymorphisms (SNPs) in the salt-taste-related gene, TRPV1, have been associated with alterations to salt-taste perception, preference, and sodium consumption. Diet quality is a known modifier of depression and anxiety and recently, sodium intake has been studied in mental health. However, the relationships between salt-taste genetics, depression, anxiety, and these dietary factors are yet to be elucidated.

METHODS

Data from the well-characterized cross-sectional Retirement Health and Lifestyle Study (n = 536, ≥65 y) were used to explore the relationships between the salt-taste SNP TRPV1-rs8065080, levels of depression and anxiety (Hospital Anxiety and Depression Scale, HADS), estimated sodium intake, and diet quality in this secondary analysis. Standard least-squares regression and nominal logistic regression modelling were used to compare continuous and categorical variables, respectively, with analyses stratified by sex.

RESULTS

Presence of the TRPV1-rs8065080 variant allele (C) was found to increase the likelihood of having depression (HADS) in the total population and in males. The associations remained significant after adjusting for sodium intake, three diet quality indices, and demographic variables, suggesting that TRPV1-rs8065080 genotype is driving the association with depression.

DISCUSSION/CONCLUSION

Future studies should explore extra-oral functions of the SNP and salt-taste receptors in the brain and the roles of neurotransmitters common to both depression and salt taste to improve the management of this increasingly prevalent and difficult-to-treat condition.

Thought Leader Perspectives on the Benefits, Barriers, and Enablers for Routinely Collected Electronic Health Data to Support Professional Development: Qualitative Study

BACKGROUND

Hospitals routinely collect large amounts of administrative data such as length of stay, 28-day readmissions, and hospital-acquired complications; yet, these data are underused for continuing professional development (CPD). First, these clinical indicators are rarely reviewed outside of existing quality and safety reporting. Second, many medical specialists view their CPD requirements as time-consuming, having minimal impact on practice change and improving patient outcomes. There is an opportunity to build new user interfaces based on these data, designed to support individual and group reflection. Data-informed reflective practice has the potential to generate new insights about performance, bridging the gap between CPD and clinical practice.

OBJECTIVE

This study aims to understand why routinely collected administrative data have not yet become widely used to support reflective practice and lifelong learning.

METHODS

We conducted semistructured interviews (N=19) with thought leaders from a range of backgrounds, including clinicians, surgeons, chief medical officers, information and communications technology professionals, informaticians, researchers, and leaders from related industries. Interviews were thematically analyzed by 2 independent coders.

RESULTS

Respondents identified visibility of outcomes, peer comparison, group reflective discussions, and practice change as potential benefits. The key barriers included legacy technology, distrust with data quality, privacy, data misinterpretation, and team culture. Respondents suggested recruiting local champions for co-design, presenting data for understanding rather than information, coaching by specialty group leaders, and timely reflection linked to CPD as enablers to successful implementation.

CONCLUSIONS

Overall, there was consensus among thought leaders, bringing together insights from diverse backgrounds and medical jurisdictions. We found that clinicians are interested in repurposing administrative data for professional development despite concerns with underlying data quality, privacy, legacy technology, and visual presentation. They prefer group reflection led by supportive specialty group leaders, rather than individual reflection. Our findings provide novel insights into the specific benefits, barriers, and benefits of potential reflective practice interfaces based on these data sets. They can inform the design of new models of in-hospital reflection linked to the annual CPD planning-recording-reflection cycle.

Type 2 and type 17 effector cells are increased in the duodenal mucosa but not peripheral blood of patients with functional dyspepsia

Background

Functional dyspepsia is characterised by chronic symptoms of post-prandial distress or epigastric pain not associated with defined structural pathology. Increased peripheral gut-homing T cells have been previously identified in patients. To date, it is unknown if these T cells were antigen-experienced, or if a specific phenotype was associated with FD.

Objective

This study aimed to characterise T cell populations in the blood and duodenal mucosa of FD patients that may be implicated in disease pathophysiology.

Methods

We identified duodenal T cell populations from 23 controls and 49 Rome III FD patients by flow cytometry using a surface marker antibody panel. We also analysed T cell populations in peripheral blood from 37 controls and 61 patients. Where available, we examined the number of duodenal eosinophils in patients and controls.

Results

There was a shift in the duodenal T helper cell balance in FD patients compared to controls. For example, patients had increased duodenal mucosal Th2 populations in the effector (13.03 ± 16.11, 19.84 ± 15.51, p=0.038), central memory (23.75 ± 18.97, 37.52 ± 17.51, p=0.007) and effector memory (9.80±10.50 vs 20.53±14.15, p=0.001) populations. Th17 populations were also increased in the effector (31.74±24.73 vs 45.57±23.75, p=0.03) and effector memory (11.95±8.42 vs 18.44±15.63, p=0.027) subsets. Peripheral T cell populations were unchanged between FD and control.

Conclusion

Our findings identify an association between lymphocyte populations and FD, specifically a Th2 and Th17 signature in the duodenal mucosa. The presence of effector and memory cells suggest that the microinflammation in FD is antigen driven.

Defects in NLRP6, autophagy and goblet cell homeostasis are associated with reduced duodenal CRH receptor 2 expression in patients with functional dyspepsia

Functional dyspepsia (FD) affects up to 15% of the population and is characterised by recurring upper gastrointestinal (GI) symptoms occurring in the absence of clinically identifiable pathology. Psychological stress is a key factor associated with the onset of FD and locally acting hypothalamic-pituitary-adrenal (HPA) axis hormones have been implicated in GI motility and barrier dysfunction. Recent pre-clinical work has identified mechanistic pathways linking corticotropin-releasing hormone (CRH) with the innate epithelial immune protein NLRP6, an inflammasome that has been shown to regulate GI mucus secretion. We recruited twelve FD patients and twelve healthy individuals to examine whether dysregulation of hypothalamic-pituitary adrenal (HPA) axis hormones and altered NLRP6 pathways were evident in the duodenal mucosa. Protein expression was assessed by immunoblot and immunohistochemistry in D2 duodenal biopsies. Plasma HPA axis hormones were assayed by ELISA and enteroid and colorectal cancer cell line cultures were used to verify function. FD patients exhibited reduced duodenal CRH-receptor 2, compared to non-GI disease controls, indicating a dysregulation of duodenal HPA signalling. The loss of CRH-receptor 2 correlated with reduced NLRP6 expression and autophagy function, processes critical for maintaining goblet cell homeostasis. In accordance, duodenal goblet cell numbers and mucin exocytosis was reduced in FD patients compared to controls. In vitro studies demonstrated that CRH could reduce NLRP6 in duodenal spheroids and promote mucus secretion in the HT29-MTX-E12 cell line. In conclusion, FD patients exhibit defects in the NLRP6-autophagy axis with decreased goblet cell function that may drive symptoms of disease. These features correlated with loss of CRH receptor 2 and may be driven by dysregulation of HPA signalling in the duodenum of FD patients.

Volatile compounds in human breath: critical review and meta-analysis

Volatile compounds contained in human breath reflect the inner workings of the body. A large number of studies have been published that link individual components of breath to disease, but diagnostic applications remain limited, in part due to inconsistent and conflicting identification of breath biomarkers. New approaches are therefore required to identify effective biomarker targets. Here, volatile organic compounds have been identified in the literature from four metabolically and physiologically distinct diseases and grouped into chemical functional groups (e.g. - methylated hydrocarbons or aldehydes; based on known metabolic and enzymatic pathways) to support biomarker discovery and provide new insight on existing data. Using this functional grouping approach, principal component analysis doubled explanatory capacity from 19.1% to 38% relative to single individual compound approaches. Random forest and linear discriminant analysis reveal 93% classification accuracy for cancer. This review and meta-analysis provides insight for future research design by identifying volatile functional groups associated with disease. By incorporating our understanding of the complexities of the human body, along with accounting for variability in methodological and analytical approaches, this work demonstrates that a suite of targeted, functional volatile biomarkers, rather than individual biomarker compounds, will improve accuracy and success in diagnostic research and application.

Bitter and sweet taste perception: relationships to self-reported oral hygiene habits and oral health status in a survey of Australian adults

Background

Oral health, an essential part of general health and well-being, is influenced by multiple factors, including oral hygiene habits and dietary factors. Dietary preferences are influenced by variation in taste perceptions and threshold tasting. Polymorphisms in specific genes for sweet and bitter taste receptors and bitter taste perception have been associated with dental caries. However, taste is complex with multiple receptors, each with multiple potential polymorphisms contributing to taste perception as well as social, cultural, and environmental influences. Additionally, these association studies have been conducted in restricted cohorts (e.g., children only). Furthermore, outcomes have been limited to dental caries and studies between taste perception and oral hygiene habits have not been completed.

Methods

A cross-sectional online survey was conducted to investigate the relationships between bitter and sweet taste perception (liking and intensity of index food items), self-reported oral hygiene habits and oral health (n = 518).

Results

Higher mean intensity scores for bitter (16–21%) and sweet (< 5%-60%) were seen with higher frequencies of oral hygiene habits (brushing, use of mouthwash, chewing gum and tongue cleaning). Lower mean bitter liking scores (18–21%) were seen with higher frequencies of oral hygiene habits (brushing, mouthwash use, floss use and chewing gum). Sweet liking scores varied by reported frequency of mouthwash use and flossing only, with mixed patterns of variance. Mean bitter and sweet intensity perception scores varied with the number of dental caries ((13–20% higher in those with 3 or more caries, compared to none).

Conclusions

While there were numerous relationships identified between liking and perception of sweet and bitter and oral health outcomes, the magnitude and direction of associations varied by outcome. The direction of the associations cannot be inferred due to the cross-sectional nature of the study. The demonstrated relationships justify further future investigations, which could help better understand if taste liking and perception is impacted by oral hygiene and health, or vice versa. This could be important in understanding the causation and progression of oral health diseases or the development of novel therapeutics for oral health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01910-8.

Sour Taste SNP KCNJ2-rs236514 and Differences in Nutrient Intakes and Metabolic Health Markers in the Elderly

Single nucleotide polymorphisms (SNPs) in taste receptors influence dietary choices that contribute to health and quality of life. Individual differences in sour taste perception and preference have been linked to heritable genetics, yet the impact of sour taste receptor SNPs on sour taste is under-researched, and studies on sour taste SNP associations to diet and health are lacking. Therefore, this study explored the relationships between the sour taste SNP KCNJ2-rs236514 and estimated macronutrient, vitamin and mineral intakes, and markers of metabolic health. Associations were explored in 523 participants aged 65 years and older with data analysed using standard least squares and nominal logistic regression modelling with post hoc student's t-tests and Tukey's HSD. Associations were found between the presence of the KCNJ2-rs236514 variant allele (A) and lower intakes of energy, total fat, monounsaturated fat and saturated fat. The lower fat intakes were significant in female carriers of the variant allele (A), along with lower water intake. Lower retinol, riboflavin, folate, calcium and sodium intakes were found in the KCNJ2-A allele carriers. In females, the variant allele was associated with lower sodium intake before and after Bonferroni adjustment. Higher body mass index, waist and waist-to-hip ratio measures were found in males carrying the variant allele. Lower levels of liver function biomarkers were associated with the presence of the KCNJ2-A allele. Overall and in males, the variant's association to lower gamma-glutamyl transferase (GGT) levels remained significant after Bonferroni adjustments. These novel findings suggest the sour taste SNP, KCNJ2-rs236514, may be modifying macronutrient, vitamin and mineral intakes, and markers of metabolic health. Research on the extra-oral functions of this SNP may improve health outcomes for those with overweight, obesity and liver disease.

Biophysical evidence to support and extend the vitamin D-folate hypothesis as a paradigm for the evolution of human skin pigmentation

OBJECTIVE

To test the "vitamin D-folate hypothesis for the evolution of human skin pigmentation."

METHODS

Total ozone mapping spectrometer (TOMS) satellite data were used to examine surface UV-irradiance in a large (n = 649) Australian cross-sectional study population. Genetic analysis was used to score vitamin D- and folate-related gene polymorphisms (n = 22), along with two pigmentation gene variants (IRF4-rs12203592/HERC2-rs12913832). Red cell folate and vitamin D₃ were measured by immunoassay and HPLC, respectively.

RESULTS

Ultraviolet radiation (UVR) and pigmentation genes interact to modify blood vitamin levels; Light skin IRF4-TT genotype has greatest folate loss while light skin HERC2-GG genotype has greatest vitamin D₃ synthesis (reflected in both TOMS and seasonal data). UV-wavelength exhibits a dose-response relationship in folate loss within light skin IRF4-TT genotype (305 > 310 > 324 > 380 nm). Significant vitamin D₃ photosynthesis only occurs within light skin HERC2-GG genotype, and is maximal at 305 nm. Three dietary antioxidants (vitamins C, E, and β-carotene) interact with UVR and pigmentation genes preventing oxidative loss of labile reduced folate vitamers, with greatest benefit in light skin IRF4-TT subjects. The putative photosensitiser, riboflavin, did not sensitize red cell folate to UVR and actually afforded protection. Four genes (5xSNPs) influenced blood vitamin levels when stratified by pigmentation genotype; MTHFR-rs1801133/rs1801131, TS-rs34489327, CYP24A-rs17216707, and VDR-ApaI-rs7975232. Lightest IRF4-TT/darkest HERC2-AA genotype combination (greatest folate loss/lowest vitamin D₃ synthesis) has 0% occurrence. The opposing, commonest (39%) compound genotype (darkest IRF4-CC/lightest HERC2-GG) permits least folate loss and greatest synthesis of vitamin D₃ .

CONCLUSION

New biophysical evidence supports the vitamin D-folate hypothesis for evolution of skin pigmentation.

Genetic Variation in the Bitter Receptors Responsible for Epicatechin Detection Are Associated with BMI in an Elderly Cohort

Globally, more than one-third of adults are overweight. Overweight and obesity are complex and multifaceted conditions, associated with an increased risk of chronic illness and early mortality. While there are known risk factors, these alone do not fully explain the varying outcomes between individuals. Recently, taste receptors have been proposed to have a role in the risk for obesity. These receptors are expressed throughout the gastrointestinal tract. In this system, they may be involved in modulating dietary intake and metabolic processes. The taste 2 family of receptors (T2Rs) detects bitter compounds. Receptors T2R4 and T2R5 detect (-)-epicatechin (epicatechin), an antioxidant polyphenol, which may have protective effects against obesity. However, the potential role for taste receptors in this association has not been explored. This study assessed whether polymorphisms in TAS2R4 (rs2233998 and rs2234001) and TAS2R5 (rs2227264) were associated with body mass index (BMI). Genotyping (Taqman qPCR assays) was performed on DNA extracted from blood samples (n = 563) from an elderly cohort. Homozygosity for the minor allele of all polymorphisms was significantly associated with a lower BMI in males. The TAS2R4-rs2233998 CC genotype, the TAS2R4-rs2234001 CC genotype and the TAS2R5-rs2227264 TT genotype were associated with lower BMI (2.1, 2.1 and 2.2 units; p = 0.002, 0.003 and 0.001, respectively). Epicatechin intake was not associated with BMI and genotype was not associated with epicatechin intake. This suggests that the association between TAS2R genotype and elevated BMI risk occurs through altered extra-oral responses and not directly via altered epicatechin intake.

A Rapid Review of Prescribing Education Interventions

INTRODUCTION

Many studies conducted on the causes and nature of prescribing errors have highlighted the inadequacy of teaching and training of prescribers. Subsequently, a rapid review was undertaken to update on the nature and effectiveness of educational interventions aimed at improving the prescribing skills and competencies.

METHODS

Twenty-two studies taking place between 2009 and 2019 were identified across nine databases.

RESULTS AND DISCUSSION

This review reinforced the importance of the WHO Guide to Good Prescribing to prescribing curriculum design as well as the effectiveness of small group teaching. However, it also highlighted the lack of innovation in prescribing education and lack of longitudinal follow-up regarding the effectiveness of prescribing education interventions.

What makes a model prescriber? A documentary analysis

INTRODUCTION

In recent years, the authority to prescribe medications in healthcare has expanded to include pharmacists, nurses and Allied Healthcare Professionals. Subsequently, the quantity of guidelines describing appropriate prescribing practice has increased. Despite this, the literature notes a lack of consensus regarding the overall qualities of a good prescriber. The aim of this study was to attempt to define what makes a model prescriber in practice, regardless of professional background.

METHODS

A documentary analysis of UK-based and international prescribing practice guidelines was performed. Data analysis was conducted through a constructivist grounded theory approach to enable concepts to be identified from the data itself without the use of pre-defined categories.

RESULTS

A total of 13 guideline documents were analysed. Overall, four core categories of a model prescriber in practice were identified: Knowledgeable: including that of disease and drug properties; Safe: relating to appropriate drug quantities and treatment-monitoring; Good Communicators: with both patients and colleagues; Contemporary: through enhancing knowledge and skills.

CONCLUSIONS

These four categories can serve as a definition of a high-level prescriber and as an additional tool for prescribing educators to evaluate the extent their curriculum develops and assesses the core qualities needed by their students to be high-level prescribers in practice.

Factors associated with the development of acute general surgical pathology in medical in-patients

BACKGROUND

Medical inpatients can develop acute general surgical conditions. However, this is rare. The presence of multiple acute pathologies delays diagnosis and these patients have poorer prognoses.

AIM

To determine the incidence, risk factors and prognosis of medical inpatients developing acute general surgical conditions.

METHODS

A single-centre retrospective case-control study was conducted over one year in the United Kingdom. Medical patients developing acute surgical pathology were identified using the local referral system. For each case, two controls were selected from a pool of medical in-patients receiving no general surgical input during their admission. Patient records were used to collect hospital admission details, demographic and laboratory data. Univariate analysis and multi-variable analysis were performed.

RESULTS

The study included 42 cases and 84 controls. The incidence of general surgical pathology in medical in-patients was 2.3/1000 admissions/year. In multivariate analysis, risk factors associated with developing general surgical pathology were previous abdominal surgery (Odds Ratio [OR] =3.68, 95% Confidence interval [CI]: 1.43 to 9.48, p=0.007) and doubling from baseline creatinine (OR=18.9, 95%CI: 2.57 to 139, p=0.004). Patients with surgical pathology had longer in-patient stays (22.8 vs 9.4 days, p<0.001) and a higher inpatient mortality (23.8% vs 7.1%, p=0.011). Development of surgical pathology was strongly associated with mortality (OR=4.06, 95%CI: 1.36 to 12.1).

CONCLUSION

The development of acute surgical pathology in medical in-patients is rare but associated with longer in-patient stays and higher mortality. We have identified risk-factors associated with the development of surgical pathology which can be used to identify patients at risk of surgical pathology. This article is protected by copyright. All rights reserved.

The impact of inflammatory bowel disease on sexual health in men: A scoping review

AIMS AND OBJECTIVES

To review the literature on the impact of inflammatory bowel disease on the sexual health of men and make recommendations for nursing practice and research.

BACKGROUND

Inflammatory bowel disease is a chronic condition of the gastrointestinal tract, causing symptoms that may impact upon sexual health. Specialist nurses are well positioned to assess and manage sexual health, but there is a lack of clinical guidance, especially in relation to men.

DESIGN

A systematic scoping review following the Arksey and O'Malley (International Journal of Social Research Methodology, 8, 2005, 19) framework reported in line with the PRISMA-ScR checklist (Tricco et al., Annals of Internal Medicine, 169, 2018, 467).

METHODS

OVID MEDLINE ALL [R], OVID EMBASE [R], OVID PsychINFO, EBSCO CINAHL Complete, The Cochrane Library and ProQuest were searched. Inclusion and exclusion criteria were applied independently by two reviewers. Data were extracted, charted and summarised from eligible studies.

RESULTS

Thirty-one studies met the inclusion criteria. These were synthesised under three categories: mediators, moderators and descriptors of sexual health. Depression, disease activity and surgery were the most commonly cited disease-related factors to affect sexual health in men. The most commonly used assessment tool was The International Index of Erectile Function. Descriptors of function included frequency of intercourse, libido and the ability to maintain a desired sexual role.

CONCLUSIONS

The effect of inflammatory bowel disease on sexual health in men involves a complex interaction of physical and psychosocial factors. Researchers must explore areas outside of erectile function to understand how the disease impacts sexuality, sexual well-being and masculinity. This can be achieved through qualitative exploration of patient, partner and health professional experiences.

RELEVANCE TO CLINICAL PRACTICE

A holistic nursing assessment of men with inflammatory bowel disease should include sexual health. Developing understanding of how the disease influences sexual interaction and expression will facilitate support that is relevant, accessible and of value to men living with the disease.

Intense Sweeteners, Taste Receptors and the Gut Microbiome: A Metabolic Health Perspective

Intense sweeteners (IS) are often marketed as a healthier alternative to sugars, with the potential to aid in combating the worldwide rise of diabetes and obesity. However, their use has been counterintuitively associated with impaired glucose homeostasis, weight gain and altered gut microbiota. The nature of these associations, and the mechanisms responsible, are yet to be fully elucidated. Differences in their interaction with taste receptors may be a potential explanatory factor. Like sugars, IS stimulate sweet taste receptors, but due to their diverse structures, some are also able to stimulate bitter taste receptors. These receptors are expressed in the oral cavity and extra-orally, including throughout the gastrointestinal tract. They are involved in the modulation of appetite, glucose homeostasis and gut motility. Therefore, taste genotypes resulting in functional receptor changes and altered receptor expression levels may be associated with metabolic conditions. IS and taste receptors may both interact with the gastrointestinal microbiome, and their interactions may potentially explain the relationship between IS use, obesity and metabolic outcomes. While these elements are often studied in isolation, the potential interactions remain unexplored. Here, the current evidence of the relationship between IS use, obesity and metabolic outcomes is presented, and the potential roles for interactions with taste receptors and the gastrointestinal microbiota in modulating these relationships are explored.

Independent and Interactive Influences of Environmental UVR, Vitamin D Levels, and Folate Variant MTHFD1-rs2236225 on Homocysteine Levels

Elevated homocysteine (Hcy) levels are a risk factor for vascular diseases. Recently, increases in ultraviolet radiation (UVR) have been linked to decreased Hcy levels. This relationship may be mediated by the status of UVR-responsive vitamins, vitamin D and folate, and/or genetic variants influencing their levels; however, this has yet to be examined. Therefore, the independent and interactive influences of environmental UVR, vitamin D and folate levels and related genetic variants on Hcy levels were examined in an elderly Australian cohort (n = 619). Red blood cell folate, 25-hydroxyvitamin D (25(OH)D), and plasma Hcy levels were determined, and genotyping for 21 folate and vitamin D-related variants was performed. Erythemal dose rate accumulated over six-weeks (6W-EDR) and four-months (4M-EDR) prior to clinics were calculated as a measure of environmental UVR. Multivariate analyses found interactions between 6W-EDR and 25(OH)D levels (pinteraction = 0.002), and 4M-EDR and MTHFD1-rs2236225 (pinteraction = 0.006) in predicting Hcy levels. The association between 6W-EDR and Hcy levels was found only in subjects within lower 25(OH)D quartiles (<33.26 ng/mL), with the association between 4M-EDR and Hcy occurring only in subjects carrying the MTHFD1-rs2236225 variant. 4M-EDR, 6W-EDR, and MTHFD1-rs2236225 were also independent predictors of Hcy. Findings highlight nutrient-environment and gene-environment interactions that could influence the risk of Hcy-related outcomes.

Distribution of variants in multiple vitamin D-related loci (DHCR7/NADSYN1, GC, CYP2R1, CYP11A1, CYP24A1, VDR, RXRα and RXRγ) vary between European, East-Asian and Sub-Saharan African-ancestry populations

BACKGROUND

The frequency of vitamin D-associated gene variants appear to reflect changes in long-term ultraviolet B radiation (UVB) environment, indicating interactions exist between the primary determinant of vitamin D status, UVB exposure and genetic disposition. Such interactions could have health implications, where UVB could modulate the impact of vitamin D genetic variants identified as disease risk factors. However, the current understanding of how vitamin D variants differ between populations from disparate UVB environments is limited, with previous work examining a small pool of variants and restricted populations only.

METHODS

Genotypic data for 46 variants within multiple vitamin D-related loci (DHCR7/NADSYN1, GC, CYP2R1, CYP11A1, CYP27A1, CYP24A1, VDR, RXRα and RXRγ) was collated from 60 sample sets (2633 subjects) with European, East Asian and Sub-Saharan African origin via the NCBI 1000 Genomes Browser and ALFRED (Allele Frequency Database), with the aim to examine for patterns in the distribution of vitamin D-associated variants across these geographic areas.

RESULTS

The frequency of all examined genetic variants differed between populations of European, East Asian and Sub-Saharan African ancestry. Changes in the distribution of variants in CYP2R1, CYP11A1, CYP24A1, RXRα and RXRγ genes between these populations are novel findings which have not been previously reported. The distribution of several variants reflected changes in the UVB environment of the population's ancestry. However, multiple variants displayed population-specific patterns in frequency that appears not to relate to UVB changes.

CONCLUSIONS

The reported population differences in vitamin D-related variants provides insight into the extent by which activity of the vitamin D system can differ between cohorts due to genetic variance, with potential consequences for future dietary recommendations and disease outcomes.

Relationship Between B-Vitamin Biomarkers and Dietary Intake with Apolipoprotein E є4 in Alzheimer's Disease

The potential for B-vitamins to reduce plasma homocysteine (Hcy) and reduce the risk of Alzheimer's disease (AD) has been described previously. However, the role of Apolipoprotein E є4 (APOE4) in this relationship has not been adequately addressed. This case-control study explored APOE4 genotype in an Australian sample of 63 healthy individuals (female = 38; age = 76.9 ± 4.7 y) and 63 individuals with AD (female = 35, age = 77.1 ± 5.3 y). Findings revealed 55 of 126 participants expressed the APOE4 genotype with 37 of 126 having both AD and the APOE4 genotype. Analysis revealed an increased likelihood of AD when Hcy levels are >11.0 µmol/L (p = 0.012), cysteine levels were <255 µmol/L (p = 0.033) and serum folate was <22.0 nmol/L (p = 0.003; in males only). In females, dietary intake of total folate <336 µg/day (p=0.001), natural folate <270 µg/day (p = 0.011), and vitamin B2 < 1.12 mg/day (p = 0.028) was associated with an increased AD risk. These results support Hcy, Cys, and SF as useful biomarkers for AD, irrespective of APOE4 genotype and as such should be considered as part of screening and managing risk of AD.

Population based study: atopy and autoimmune diseases are associated with functional dyspepsia and irritable bowel syndrome, independent of psychological distress

BACKGROUND

The pathogenesis of functional GI disorders (FGIDs) is uncertain. However, underlying immune activation and psychological distress has been documented in irritable bowel syndrome (IBS) and functional dyspepsia (FD). Epidemiological data from the UK suggest that FGIDs are linked to atopy and certain autoimmune diseases but this has not been confirmed.

AIM

To test if allergic or autoimmune diseases are independently associated with FGIDs, irrespective of psychological distress in a large population based study.

METHODS

A total of 3542 people (mean age 57.9 years and 52.7% females) randomly selected from the Australian population, returned a mail survey (response rate = 43%). The survey asked about a physician diagnosis of autoimmune disease (scleroderma, psoriasis, rheumatoid arthritis and diabetes mellitus) or allergic conditions (asthma, food, pollen and/or animal allergy). The questionnaire assessed psychological distress and Rome III criteria for FD and IBS.

RESULTS

Asthma, food, pollen and animal allergies, psoriasis and rheumatoid arthritis were univariately significantly associated with IBS and FD. Food allergy (OR = 1.66; 95% CI = 1.15-2.40, P = 0.007), psoriasis (OR = 1.81; 95% CI = 1.19-2.74, P = 0.006) and rheumatoid arthritis (OR = 1.68; 95% CI = 1.15-2.4, P = 0.007) were independent risk factors for IBS, controlling for age, gender and psychological distress. In FD, asthma (OR = 1.32; 95% CI = 1.04-1.68, P = 0.025) and food allergy (OR = 1.78; 95% CI = 1.28-2.49, P = 0.001) were independent predictors, controlling for age, sex and psychological distress.

CONCLUSIONS

There is evidence that both atopic and autoimmune diseases are risk factors for FGIDs, independent of psychological distress, differing in IBS and FD. This provides evidence that different peripheral pathways may be involved in the pathogenesis of certain FGIDs.

Reply: "Comment on: The Vitamin D⁻Folate Hypothesis as an Evolutionary Model for Skin Pigmentation: An Update and Integration of Current Ideas, Nutrients , 10, 554"

We thank Elias and Williams for their interest in our review [...].

Standard setting in Australian medical schools

BACKGROUND

Standard setting of assessment is critical in quality assurance of medical programs. The aims of this study were to identify and compare the impact of methods used to establish the passing standard by the 13 medical schools who participated in the 2014 Australian Medical Schools Assessment Collaboration (AMSAC).

METHODS

A survey was conducted to identify the standard setting procedures used by participating schools. Schools standard setting data was collated for the 49 multiple choice items used for benchmarking by AMSAC in 2014. Analyses were conducted for nine schools by their method of standard setting and key characteristics of 28 panel members from four schools.

RESULTS

Substantial differences were identified between AMSAC schools that participated in the study, in both the standard setting methods and how particular techniques were implemented. The correlation between the item standard settings data by school ranged from - 0.116 to 0.632. A trend was identified for panel members to underestimate the difficulty level of hard items and overestimate the difficulty level of easy items for all methods. The median derived cut-score standard across schools was 55% for the 49 benchmarking questions. Although, no significant differences were found according to panel member standard setting experience or clinicians versus scientists, panel members with a high curriculum engagement generally had significantly lower expectations of borderline candidates (p = 0.044).

CONCLUSION

This study used a robust assessment framework to demonstrate that several standard setting techniques are used by Australian medical schools, which in some cases use different techniques for different stages of their program. The implementation of the most common method, the Modified Angoff standard setting approach was found to vary markedly. The method of standard setting used had an impact on the distribution of expected minimally competent student performance by item and overall, with the passing standard varying by up to 10%. This difference can be attributed to the method of standard setting because the ASMSAC items have been shown over time to have consistent performance levels reflecting similar cohort ability. There is a need for more consistency in the method of standard setting used by medical schools in Australia.

InsuTAG: A novel physiologically relevant predictor for insulin resistance and metabolic syndrome

The aim of this study was to investigate whether a novel physiologically relevant marker, InsuTAG (fasting insulin × fasting triglycerides) can predict insulin resistance (IR) and metabolic syndrome (MetS). Data of 618 participants from the Retirement Health and Lifestyle Study (RHLS) were evaluated for the current study. IR was defined by homeostatic model assessment (HOMA-IR) scores. Pearson correlations were used to examine the associations of InsuTAG with HOMA-IR and other markers. Predictions of IR from InsuTAG were evaluated using multiple regression models. Receiver operating characteristic curves (ROC) were constructed to measure the sensitivity and specificity of InsuTAG values and to determine the optimum cut-off point for prediction of IR. InsuTAG was positively correlated with HOMA-IR (r = 0.86; p < 0.0001). InsuTAG is a strong predictor of IR accounting for 65.0% of the variation in HOMA-IR values after adjusting for potential confounders. Areas under the ROC curve showed that InsuTAG (0.93) has higher value than other known lipid markers for predicting IR, with a sensitivity and specificity of 84.15% and 86.88%. Prevalence of MetS was significantly (p < 0.0001) higher in subjects with InsuTAG values greater than optimal cut-off value of 11.2. Thus, InsuTAG appears to be a potential feasible marker of IR and metabolic syndrome.

Undiagnosed pancreatic exocrine insufficiency and chronic pancreatitis in functional GI disorder patients with diarrhea or abdominal pain

BACKGROUND AND AIM

A previous UK study showed that 6.1% of patients with diarrhea-predominant irritable bowel syndrome (IBS-D) had evidence of severe pancreatic exocrine insufficiency (PEI), but these findings need replication. We aimed to identify the prevalence of PEI based on fecal elastase stool testing in consecutive outpatients presenting with chronic unexplained abdominal pain and/or diarrhea and/or IBS-D.

METHODS

Patients aged over 40 years presenting to hospital outpatient clinics from six sites within Australia with unexplained abdominal pain and/or diarrhea for at least 3 months and/or IBS-D were studied. Patients completed validated questionnaires and donated a stool sample in which elastase concentration was measured by ELISA. A concentration of < 100 mcg/g stool represented severe and < 200 mcg/g mild to moderate PEI. Patients whose fecal elastase was < 200 mcg/g underwent testing for pancreatic pathology with an endoscopic ultrasound or abdominal CT.

RESULTS

Two hundred eighteen patients (mean age of 60 years, 29.4% male) were studied. PEI was found in 4.6% (95% CI 2.2-8.3%) (n = 10), with five patients (2.3% (95% CI 0.8-5.3%) having severe PEI. Only male sex and heavy alcohol use were significantly associated with abnormal versus normal pancreatic functioning. Of seven patients who underwent endoscopic ultrasound or CT, two had features indicative of chronic pancreatitis.

CONCLUSION

One in 50 patients with IBS-D or otherwise unexplained abdominal pain or diarrhea have an abnormal fecal elastase, but unexpected pancreatic insufficiency was detected in only a minority of these. This study failed to confirm the high prevalence of PEI among patients with unexplained GI symptoms previously reported.

Regulation of IL-12p40 by HIF controls Th1/Th17 responses to prevent mucosal inflammation

Intestinal inflammatory lesions are inherently hypoxic, due to increased metabolic demands created by cellular infiltration and proliferation, and reduced oxygen supply due to vascular damage. Hypoxia stabilizes the transcription factor hypoxia-inducible factor-1α (HIF) leading to a coordinated induction of endogenously protective pathways. We identified IL12B as a HIF-regulated gene and aimed to define how the HIF-IL-12p40 axis influenced intestinal inflammation. Intestinal lamina propria lymphocytes (LPL) were characterized in wild-type and IL-12p40^-/- murine colitis treated with vehicle or HIF-stabilizing prolyl-hydroxylase inhibitors (PHDi). IL12B promoter analysis was performed to examine hypoxia-responsive elements. Immunoblot analysis of murine and human LPL supernatants was performed to characterize the HIF/IL-12p40 signaling axis. We observed selective induction of IL-12p40 following PHDi-treatment, concurrent with suppression of Th1 and Th17 responses in murine colitis models. In the absence of IL-12p40, PHDi-treatment was ineffective. Analysis of the IL12B promoter identified canonical HIF-binding sites. HIF stabilization in LPLs resulted in production of IL-12p40 homodimer which was protective against colitis. The selective induction of IL-12p40 by HIF-1α leads to a suppression of mucosal Th1 and Th17 responses. This HIF-IL12p40 axis may represent an endogenously protective mechanism to limit the progression of chronic inflammation, shifting from pro-inflammatory IL-12p70 to an antagonistic IL-12p40 homodimer.

A potential sex dimorphism in the relationship between bitter taste and alcohol consumption

BACKGROUND

Bitterness is an innate aversive taste important in detecting potentially toxic substances, including alcohol. However, bitter compounds exist in many foods and beverages, and can be desirable, such as in beer. TAS2R38 is a well-studied bitter taste receptor with common polymorphisms. Some have reported relationships between TAS2R38 genotypes, bitter taste phenotype and alcohol intake, however results have been mixed. These mixed results may be explained by the varying taste properties of different alcoholic beverages or a sex dimorphism in responses.

METHODS

Bitter taste phenotype was assessed using PROP taste test and TAS2R38-P49A genotype was assessed by RFLP-PCR. Alcohol intake was assessed by food frequency questionnaire and classified by beverage type (beer, wine, spirits or mixed drinks). The relationships between bitter taste phenotype and carriage of the P allele of the TAS2R38-A49P gene and alcohol intake were assessed adjusted for and stratified by sex, and the interaction between taste and sex was evaluated.

RESULTS

The relationship between alcohol intake and bitter taste phenotype varied by beverage type, with significant results for beer, spirits and mixed drinks, but not wine. When stratified, results varied by sex, and were only significant in males. Significant interactions were found for taster phenotype and sex (total alcohol intake and intake of beer and spirits). Results were similar for carriage of the TAS2R38-P49A P allele.

CONCLUSIONS

Sex-specific interactions between bitter taste phenotype, TAS2R38 genotype and alcohol intake may explain variance in previous studies and may have implications for sex-specific disease risk and public health interventions.

Is the long case dead? 'Uh, I don't think so': the Uh/Um Index

Current tools for clinical assessment are tedious and time-consuming, particularly the dreadful long case. There is a need for novel instruments that incorporate other aspects of competence. We propose such a method, namely the Uh/Um Index. Our innovation paper describes the rationale for using speech dysfluency and occurrences of filler words such as 'uh' and 'um' as a proxy for competence. This appears to have won initial support from senior clinicians in our institution. Additional research is needed (non-restricted grants are welcomed) to establish rigorous standard setting and to fund our attendance at overseas conferences to make the Uh/Um Index the new buzzword in medical education.

Gene-Nutrient Interaction between Folate and Dihydrofolate Reductase in Risk for Adenomatous Polyp Occurrence: A Preliminary Report

Folate and related gene variants are significant risk factors in the aetiology of colorectal cancer. Dihydrofolate reductase (DHFR) is critical in the metabolism of synthetic folic acid (pteroylmonoglutamatamic, PteGlu) to tetrahydrofolate following absorption. Therefore, the 19bp deletion variant of DHFR may lead to the alteration of folate-related colorectal disease susceptibility. This study examined the association between PteGlu and 19bp del-DHFR, and adenomatous polyp (AP) occurrence, an antecedent of colorectal cancer. A total of 199 subjects (162 controls and 37 AP cases) were analysed to determine dietary intake of total folate, natural methylfolate and synthetic PteGlu, level of erythrocyte folate and plasma homocysteine (tHcy), and genotype of 19bp del-DHFR. Dietary folate intake, erythrocyte folate, tHcy and 19bp del-DHFR variants did not independently predict the occurrence of AP. However, a gene-nutrient interaction was observed when subjects were stratified according to dietary folate intake. In subjects with a folate intake above the median value due to significant dietary PteGlu content, the presence of the 19bp-deletion allele decreased the risk for AP (OR=0.35, 95% CI: 0.13-0.97). However, such association was not evident in individuals with a folate intake below the median value. In conclusion, the finding suggests that folate nutrition and 19bp del-DHFR variation may interact to modify AP risk.

Association between omega-3 index and blood lipids in older Australians

Management of hyperlipidaemia remains a cornerstone therapy for the prevention of cardiovascular disease (CVD). Dietary supplementation with n-3 polyunsaturated fatty acid (PUFA) has been shown to modulate blood lipid profiles and reduce the risk of developing CVD. However, studies relating objective measures of long-term dietary n-3 PUFA intake and circulating lipid levels in older adults are limited. Thus, we aimed to determine whether there is an association between erythrocyte n-3 PUFA status (omega-3 index, O3I) and blood lipid profiles in older adults. A sample of adults aged 65-95 years who participated in the Retirement Health and Lifestyle Study was evaluated. Outcome measures included O3I (% eicosapentaenoic acid+% docosahexaenoic acid) and fasting blood lipid profiles [total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol and triglyceride (TG)]. Two hundred and seventy-six subjects were included in the analyses. The mean±SD age was 77.6±7.4 years, and 40.9% were males. O3I was significantly higher in females compared to males. O3I was inversely associated with plasma TG (P<.001) and TC/HDL-cholesterol ratio (P<.05), and positively associated with HDL-cholesterol (P<.05), in all subjects. Associations between O3I and TG were evident in both females (r=-0.250, P<.01) and males (r=-0.225, P<.05). In females only, the odds of being hypertriglyceridaemic were highest in those with lowest O3I (P=.006). Trends for hypercholesterolaemia and elevated LDL risk were converse between males and females. Long-term n-3 PUFA status is associated with blood lipid profiles in older Australians. Our findings support the development and implementation of age-specific dietary strategies to reduce the risk of CVD via improving the O3I.

Bitter taste genetics--the relationship to tasting, liking, consumption and health

Bitter is the most complex of human tastes, and is arguably the most important. Aversion to bitter taste is important for detecting toxic compounds in food; however, many beneficial nutrients also taste bitter and these may therefore also be avoided as a consequence of bitter taste. While many polymorphisms in TAS2R genes may result in phenotypic differences that influence the range and sensitivity of bitter compounds detected, the full extent to which individuals differ in their abilities to detect bitter compounds remains unknown. Simple logic suggests that taste phenotypes influence food preferences, intake and consequently health status. However, it is becoming clear that genetics only plays a partial role in predicting preference, intake and health outcomes, and the complex, pleiotropic relationships involved are yet to be fully elucidated.

Folate status, folate-related genes and serum miR-21 expression: Implications for miR-21 as a biomarker

BACKGROUND

Free circulating microRNA (miRNA) in serum may be valuable biomarkers for disease diagnosis and prognosis. miR-21, the archetypal oncogenic miRNA, has been proposed as a biomarker for colorectal cancer and its benign precursor, adenomatous polyps. However, it is now becoming clear that circulating miRNA profiles may be sensitive to lifestyle and environmental influences. Dietary components involved in one-carbon metabolism are particularly well placed to modulate miRNA expression through an influence on DNA methylation pathways.

METHODS

We investigated the role of methyl group donors (folate, B12, cysteine, homocysteine), polymorphisms of the enzymes of one-carbon metabolism, and serum miR-21 expression in a primary case-control cohort (colonoscopy confirmed adenomatous colon polyps vs controls; n = 253) and a secondary cross-sectional cohort (over 65s; n = 649). The relationships between these parameters and serum miR-21 levels were assessed, stratified by gender.

CONCLUSIONS

Serum miR-21 expression was related to occurrence of adenomatous polyps in females, but not males. Folate levels and MTHFR-C677T genotype was associated with miR-21 expression in both genders. Additionally, DHFR-19 del and MSR-A66G were associated with miR-21 expression in females and males, respectively. Stimulation with excess folate increased expression of miR-21 in colon cancer cell lines.

GENERAL SIGNIFICANCE

This study demonstrates that serum miR-21 expression correlates with folate status and related genetic status. This may have consequences for the proposed use of miR-21 as a colorectal cancer biomarker.

Genetic Variation in Glutamate Carboxypeptidase II and Interaction with Dietary Natural Vitamin C May Predict Risk for Adenomatous Polyp Occurrence

BACKGROUND

The C1561T variant of the glutamate carboxypeptidase II (GCPII) gene is critical for natural methylfolylpolyglutamte (methylfolate) absorption, and has been associated with perturbations in folate metabolism and disease susceptibility. However, little is known on C1561T-GCPII as a risk factor for colorectal cancer. Therefore, this study examined whether C1561T-GCPII influences folate metabolism and adenomatous polyp occurrence.

MATERIALS AND METHODS

164 controls and 38 adenomatous polyp cases were analysed to determine blood folate and plasma homocysteine (Hcy) level, dietary intake of natural methylfolate, synthetic pteroylglutamic acid (PteGlu), vitamin C and C1561T-GCPII genotype.

RESULTS

In controls and cases, 7.3 and 18.4 percent of subjects respectively, were found to have the CT genotype, increasing the risk for adenomatous polyp occurrence 2.86 times (95% CI:1.37-8.0, p=0.035). Total dietary folate, methylfolate and PteGlu intake and the level of erythrocyte folate and plasma Hcy did not predict the occurrence of an adenomatous polyp. However, dietary natural vitamin C intake was associated with adenomatous polyp risk within C1561T-GCPII CT genotype subjects (p=0.037).

CONCLUSIONS

The findings suggest that C1561T-GCPII variation may be associated with risk for adenomatous polyp, and vitamin C may modify risk by interacting with the variant gene, its expression product and/or folate substrates.