Faecal microbial transfer and complex carbohydrates mediate protection against COPD

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is a major cause of global illness and death, most commonly caused by cigarette smoke. The mechanisms of pathogenesis remain poorly understood, limiting the development of effective therapies. The gastrointestinal microbiome has been implicated in chronic lung diseases via the gut-lung axis, but its role is unclear.

DESIGN

Using an in vivo mouse model of cigarette smoke (CS)-induced COPD and faecal microbial transfer (FMT), we characterised the faecal microbiota using metagenomics, proteomics and metabolomics. Findings were correlated with airway and systemic inflammation, lung and gut histopathology and lung function. Complex carbohydrates were assessed in mice using a high resistant starch diet, and in 16 patients with COPD using a randomised, double-blind, placebo-controlled pilot study of inulin supplementation.

RESULTS

FMT alleviated hallmark features of COPD (inflammation, alveolar destruction, impaired lung function), gastrointestinal pathology and systemic immune changes. Protective effects were additive to smoking cessation, and transfer of CS-associated microbiota after antibiotic-induced microbiome depletion was sufficient to increase lung inflammation while suppressing colonic immunity in the absence of CS exposure. Disease features correlated with the relative abundance of Muribaculaceae, Desulfovibrionaceae and Lachnospiraceae family members. Proteomics and metabolomics identified downregulation of glucose and starch metabolism in CS-associated microbiota, and supplementation of mice or human patients with complex carbohydrates improved disease outcomes.

CONCLUSION

The gut microbiome contributes to COPD pathogenesis and can be targeted therapeutically.

Nutritional knowledge in British Army recruits during basic training

BACKGROUND

Appropriate nutritional intake is essential to optimise both general health and performance in military recruits. General nutritional knowledge is a significant and modifiable determinant of dietary behaviour; however, the level of nutritional knowledge in British Army recruits undertaking basic training is poorly understood.

METHODS

The Nutritional Knowledge Questionnaire for Athletes was completed by 29 male (age: 22.3±3.8 years) and 26 female (age: 22.0±3.0 years) standard-entry recruits at the end of basic training, and 15 male (age: 20.7±3.2 years) infantry recruits both at the start and end of basic training for the British Army. Between-group and within-group differences in total and subcomponent (ie, carbohydrate, protein, fat, vitamins and minerals, general nutrition, fluid intake, and sporting performance) scores were analysed.

RESULTS

Standard-entry male recruits had more correct answers (52%) than standard-entry female recruits (38%) and male infantry recruits (40%) at the end of training. Infantry recruits had similar levels of nutritional knowledge at the start (39% correct) and end (40% correct) of training. Nutritional knowledge related to protein (range: 53%-75% correct answers) and vitamins and minerals (range: 42%-63% correct answers) were the two highest scoring subcomponents within each group.

CONCLUSION

British Army recruits, in particular standard-entry female and infantry recruits, have poor nutritional knowledge, which did not improve throughout basic training. Better nutritional intervention, especially surrounding carbohydrate and fluid education, is required during British Army basic training to optimise career-long dietary behaviour.

Proliferation of primary human hepatocytes and prevention of hepatitis B virus reinfection efficiently deplete nuclear cccDNA in vivo

OBJECTIVE

The stability of the covalently closed circular DNA (cccDNA) in nuclei of non-dividing hepatocytes represents a key determinant of HBV persistence. Contrarily, studies with animal hepadnaviruses indicated that hepatocyte turnover can reduce cccDNA loads but knowledge on the proliferative capacity of HBV-infected primary human hepatocytes (PHHs) in vivo and the fate of cccDNA in dividing PHHs is still lacking. This study aimed to determine the impact of human hepatocyte division on cccDNA stability in vivo.

METHODS

PHH proliferation was triggered by serially transplanting hepatocytes from HBV-infected humanised mice into naïve recipients. Cell proliferation and virological changes were assessed by quantitative PCR, immunofluorescence and RNA in situ hybridisation. Viral integrations were analysed by gel separation and deep sequencing.

RESULTS

PHH proliferation strongly reduced all infection markers, including cccDNA (median 2.4 log/PHH). Remarkably, cell division appeared to cause cccDNA dilution among daughter cells and intrahepatic cccDNA loss. Nevertheless, HBV survived in sporadic non-proliferating human hepatocytes, so that virological markers rebounded as hepatocyte expansion relented. This was due to reinfection of quiescent PHHs since treatment with the entry inhibitor myrcludex-B or nucleoside analogues blocked viral spread and intrahepatic cccDNA accumulation. Viral integrations were detected both in donors and recipient mice but did not appear to contribute to antigen production.

CONCLUSIONS

We demonstrate that human hepatocyte division even without involvement of cytolytic mechanisms triggers substantial cccDNA loss. This process may be fundamental to resolve self-limiting acute infection and should be considered in future therapeutic interventions along with entry inhibition strategies.

Signalling via the osteopontin and high mobility group box-1 axis drives the fibrogenic response to liver injury

OBJECTIVE

Liver fibrosis is associated with significant collagen-I deposition largely produced by activated hepatic stellate cells (HSCs); yet, the link between hepatocyte damage and the HSC profibrogenic response remains unclear. Here we show significant induction of osteopontin (OPN) and high-mobility group box-1 (HMGB1) in liver fibrosis. Since OPN was identified as upstream of HMGB1, we hypothesised that OPN could participate in the pathogenesis of liver fibrosis by increasing HMGB1 to upregulate collagen-I expression.

DESIGN AND RESULTS

Patients with long-term hepatitis C virus (HCV) progressing in disease stage displayed enhanced hepatic OPN and HMGB1 immunostaining, which correlated with fibrosis stage, whereas it remained similar in non-progressors. Hepatocyte cytoplasmic OPN and HMGB1 expression was significant while loss of nuclear HMGB1 occurred in patients with HCV-induced fibrosis compared with healthy explants. Well-established liver fibrosis along with marked induction of HMGB1 occurred in CCl₄-injected Opn^Hep transgenic yet it was less in wild type and almost absent in Opn^-/- mice. Hmgb1 ablation in hepatocytes (Hmgb1^ΔHep) protected mice from CCl₄-induced liver fibrosis. Coculture with hepatocytes that secrete OPN plus HMGB1 and challenge with recombinant OPN (rOPN) or HMGB1 (rHMGB1) enhanced collagen-I expression in HSCs, which was blunted by neutralising antibodies (Abs) and by Opn or Hmgb1 ablation. rOPN induced acetylation of HMGB1 in HSCs due to increased NADPH oxidase activity and the associated decrease in histone deacetylases 1/2 leading to upregulation of collagen-I. Last, rHMGB1 signalled via receptor for advanced glycation end-products and activated the PI3K-pAkt1/2/3 pathway to upregulate collagen-I.

CONCLUSIONS

During liver fibrosis, the increase in OPN induces HMGB1, which acts as a downstream alarmin driving collagen-I synthesis in HSCs.

How prepared are UK medical graduates for practice? A rapid review of the literature 2009-2014

OBJECTIVE

To understand how prepared UK medical graduates are for practice and the effectiveness of workplace transition interventions.

DESIGN

A rapid review of the literature (registration #CRD42013005305).

DATA SOURCES

Nine major databases (and key websites) were searched in two timeframes (July-September 2013; updated May-June 2014): CINAHL, Embase, Educational Resources Information Centre, Health Management Information Consortium, MEDLINE, MEDLINE in Process, PsycINFO, Scopus and Web of Knowledge.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Primary research or studies reporting UK medical graduates' preparedness between 2009 and 2014: manuscripts in English; all study types; participants who are final-year medical students, medical graduates, clinical educators, patients or NHS employers and all outcome measures.

DATA EXTRACTION

At time 1, three researchers screened manuscripts (for duplicates, exclusion/inclusion criteria and quality). Remaining 81 manuscripts were coded. At time 2, one researcher repeated the process for 2013-2014 (adding six manuscripts). Data were analysed using a narrative synthesis and mapped against Tomorrow's Doctors (2009) graduate outcomes.

RESULTS

Most studies comprised junior doctors' self-reports (65/87, 75%), few defined preparedness and a programmatic approach was lacking. Six themes were highlighted: individual skills/knowledge, interactional competence, systemic/technological competence, personal preparedness, demographic factors and transitional interventions. Graduates appear prepared for history taking, physical examinations and some clinical skills, but unprepared for other aspects, including prescribing, clinical reasoning/diagnoses, emergency management, multidisciplinary team-working, handover, error/safety incidents, understanding ethical/legal issues and ward environment familiarity. Shadowing and induction smooth transition into practice, but there is a paucity of evidence around assistantship efficacy.

CONCLUSIONS

Educational interventions are needed to address areas of unpreparedness (eg, multidisciplinary team-working, prescribing and clinical reasoning). Future research in areas we are unsure about should adopt a programmatic and rigorous approach, with clear definitions of preparedness, multiple stakeholder perspectives along with multisite and longitudinal research designs to achieve a joined-up, systematic, approach to understanding future educational requirements for junior doctors.

Clinician-scientist MB/PhD training in the UK: a nationwide survey of medical school policy

OBJECTIVE

This study surveyed all UK medical schools regarding their Bachelor of Medicine (MB), Doctor of Philosophy (PhD) (MB/PhD) training policy in order to map the current training landscape and to provide evidence for further research and policy development.

SETTING

Deans of all UK medical schools registered with the Medical Schools Council were invited to participate in this survey electronically.

PRIMARY

The number of medical schools that operate institutional MB/PhD programmes or permit self-directed student PhD intercalation.

SECONDARY

Medical school recruitment procedures and attitudes to policy guidance.

FINDINGS

27 of 33 (81%) registered UK medical schools responded. Four (14%) offer an institutional MB/PhD programme. However, of those without institutional programmes, 17 (73%) permit study interruption and PhD intercalation: two do not (one of whom had discontinued their programme in 2013), three were unsure and one failed to answer the question. Regarding student eligibility, respondents cited high academic achievement in medical studies and a bachelor's or master's degree. Of the Medical schools without institutional MB/PhD programmes, 5 (21%) have intentions to establish a programme, 8 (34%) do not and 3 were unsure, seven did not answer. 19 medical schools (70%) considered national guidelines are needed for future MB/PhD programme development.

CONCLUSIONS

We report the first national survey of MB/PhD training in the UK. Four medical schools have operational institutional MB/PhD programmes, with a further five intending to establish one. Most medical schools permit study interruption and PhD intercalation. The total number MB/PhD students yet to graduate from medical school could exceed 150, with 30 graduating per year. A majority of medical school respondents to this survey believe national guidelines are required for MB/PhD programme development and implementation. Further research should focus on the MB/PhD student experience. Discussion regarding local and national MB/PhD policies between medical schools and academic stakeholders are needed.

A retrospective analysis of the effect of discussion in teleconference and face-to-face scientific peer-review panels

OBJECTIVE

With the use of teleconferencing for grant peer-review panels increasing, further studies are necessary to determine the efficacy of the teleconference setting compared to the traditional onsite/face-to-face setting. The objective of this analysis was to examine the effects of discussion, namely changes in application scoring premeeting and postdiscussion, in these settings. We also investigated other parameters, including the magnitude of score shifts and application discussion time in face-to-face and teleconference review settings.

DESIGN

The investigation involved a retrospective, quantitative analysis of premeeting and postdiscussion scores and discussion times for teleconference and face-to-face review panels. The analysis included 260 and 212 application score data points and 212 and 171 discussion time data points for the face-to-face and teleconference settings, respectively.

RESULTS

The effect of discussion was found to be small, on average, in both settings. However, discussion was found to be important for at least 10% of applications, regardless of setting, with these applications moving over a potential funding line in either direction (fundable to unfundable or vice versa). Small differences were uncovered relating to the effect of discussion between settings, including a decrease in the magnitude of the effect in the teleconference panels as compared to face-to-face. Discussion time (despite teleconferences having shorter discussions) was observed to have little influence on the magnitude of the effect of discussion. Additionally, panel discussion was found to often result in a poorer score (as opposed to an improvement) when compared to reviewer premeeting scores. This was true regardless of setting or assigned reviewer type (primary or secondary reviewer).

CONCLUSIONS

Subtle differences were observed between settings, potentially due to reduced engagement in teleconferences. Overall, further research is required on the psychology of decision-making, team performance and persuasion to better elucidate the group dynamics of telephonic and virtual ad-hoc peer-review panels.

Effects of acupuncture on cortical expression of Wnt3a, β-catenin and Sox2 in a rat model of traumatic brain injury

OBJECTIVE

To observe the effects of acupuncture treatment on the expression of Wnt/β-catenin signalling pathway-related genes (Wnt3a, β-catenin and Sox2) in the injured cerebral cortex of rats with traumatic brain injury (TBI).

METHODS

A controlled impact model of TBI was established using Feeney's free-drop method. Seventy-eight Sprague-Dawley rats were randomly divided into the following three groups: a normal group (n=18) that was left untreated; a model group (n=30) that received no treatment after TBI; and an acupuncture group (n=30) that received acupuncture (at LI4, GV20, GV26 and GV16) after TBI. Rats in each group were randomly and equally divided into 3-day, 7-day and 14-day subgroups according to the duration of therapy. Real-time fluorescence quantitative PCR (RT-qPCR) was used to measure mRNA expression of Wnt3a, β-catenin and Sox2. Western blots were performed to determine the expression levels of WNT3a, β-Catenin and SOX2.

RESULTS

Wnt3a mRNA was upregulated in the 7-day and 14-day acupuncture subgroups compared with the corresponding model subgroups (p<0.05). β-catenin expression was significantly increased in the 7-day and 14-day acupuncture subgroups compared with the corresponding model subgroups (p<0.01). In the 3-day and 7-day acupuncture subgroups, Sox2 expression was significantly higher than that in the normal and model groups (p<0.01 each). The levels of WNT3a, β-catenin and SOX2 were generally consistent with the corresponding mRNA levels.

CONCLUSIONS

Acupuncture exerts a regulatory effect on the Wnt/β-catenin signalling pathway, which may in turn influence the proliferation and differentiation of endogenous neural stem cells.

Intestinal steroidogenesis controls PPARγ expression in the colon and is impaired during ulcerative colitis

BACKGROUND AND AIMS

Immune tolerance breakdown during UC involves the peroxisome proliferator-activated receptor-γ (PPARγ), a key factor in mucosal homoeostasis and the therapeutic target of 5-aminosalycilates, which expression is impaired during UC. Here we assess the impact of glucocorticoids (GCs) on PPARγ expression, focusing especially on extra-adrenal cortisol production by colonic epithelial cells (CECs).

METHODS

Activation of PPARγ in the colon was evaluated using transgenic mice for the luciferase gene under PPAR control (peroxisome proliferator response element-luciferase mice). Protein and mRNA expression of PPARγ were evaluated with colon fragments and purified CEC from mice. Cortisol production and steroidogenic factor expression were quantified in human CEC of patients with UC and those of controls. Gene expression knockdown by short hairpin RNA in Caco-2 cells was used for functional studies.

RESULTS

GCs were able to raise luciferase activity in peroxisome proliferator response element-luciferase mice. In the mice colons and Caco-2 cells, PPARγ expression was increased either with GCs or with an inducer of steroidogenesis and then decreased after treatment with a steroidogenesis inhibitor. Cortisol production and steroidogenic factor expression, such as liver receptor homologue-1 (LRH-1), were decreased in CEC isolated from patients with UC, directly correlating with PPARγ impairment. Experiments on Caco-2 cells lacking LRH-1 expression confirmed that LRH-1 controls PPARγ expression by regulating GC synthesis in CEC.

CONCLUSIONS

These results demonstrate cortisol control of PPARγ expression in CEC, highlighting cortisol production deficiency in colonocytes as a key molecular event in the pathophysiology of UC.

Duodenal nutrient exclusion improves metabolic syndrome and stimulates villus hyperplasia

OBJECTIVE

Surgical interventions that prevent nutrient exposure to the duodenum are among the most successful treatments for obesity and diabetes. However, these interventions are highly invasive, irreversible and often carry significant risk. The duodenal-endoluminal sleeve (DES) is a flexible tube that acts as a barrier to nutrient-tissue interaction along the duodenum. We implanted this device in Zucker Diabetic Fatty (ZDF) rats to gain greater understanding of duodenal nutrient exclusion on glucose homeostasis.

DESIGN

ZDF rats were randomised to four groups: Naive, sham ad libitum, sham pair-fed, and DES implanted. Food intake, body weight (BW) and body composition were measured for 28 days postoperatively. Glucose, lipid and bile acid metabolism were evaluated, as well as histological assessment of the upper intestine.

RESULTS

DES implantation induced a sustained decrease in BW throughout the study that was matched by pair-fed sham animals. Decreased BW resulted from loss of fat, but not lean mass. DES rats were also found to be more glucose tolerant than either ad libitum-fed or pair-fed sham controls, suggesting fat mass independent metabolic benefits. DES also reduced circulating triglyceride and glycerol levels while increasing circulating bile acids. Interestingly, DES stimulated a considerable increase in villus length throughout the upper intestine, which may contribute to metabolic improvements.

CONCLUSIONS

Our preclinical results validate DES as a promising therapeutic approach to diabetes and obesity, which offers reversibility, low risk, low invasiveness and triple benefits including fat mass loss, glucose and lipid metabolism improvement which mechanistically may involve increased villus growth in the upper gut.

Myofibroblastic cells function as progenitors to regenerate murine livers after partial hepatectomy

OBJECTIVE

Smoothened (SMO), a coreceptor of the Hedgehog (Hh) pathway, promotes fibrogenic repair of chronic liver injury. We investigated the roles of SMO+ myofibroblast (MF) in liver regeneration by conditional deletion of SMO in α smooth muscle actin (αSMA)+ cells after partial hepatectomy (PH).

DESIGN

αSMA-Cre-ER(T2)×SMO/flox mice were treated with vehicle (VEH) or tamoxifen (TMX), and sacrificed 24-96 h post-PH. Regenerating livers were analysed for proliferation, progenitors and fibrosis by qRT-PCR and quantitative immunohistochemistry (IHC). Results were normalised to liver segments resected at PH. For lineage-tracing studies, αSMA-Cre-ER(T2)×ROSA-Stop-flox-yellow fluorescent protein (YFP) mice were treated with VEH or TMX; livers were stained for YFP, and hepatocytes isolated 48 and 72 h post-PH were analysed for YFP by flow cytometric analysis (FACS).

RESULTS

Post-PH, VEH-αSMA-SMO mice increased expression of Hh-genes, transiently accumulated MF, fibrosis and liver progenitors, and ultimately exhibited proliferation of hepatocytes and cholangiocytes. In contrast, TMX-αSMA-SMO mice showed loss of whole liver SMO expression, repression of Hh-genes, enhanced accumulation of quiescent HSC but reduced accumulation of MF, fibrosis and progenitors, as well as inhibition of hepatocyte and cholangiocyte proliferation, and reduced recovery of liver weight. In TMX-αSMA-YFP mice, many progenitors, cholangiocytes and up to 25% of hepatocytes were YFP+ by 48-72 h after PH, indicating that liver epithelial cells were derived from αSMA-YFP+ cells.

CONCLUSIONS

Hh signalling promotes transition of quiescent hepatic stellate cells to fibrogenic MF, some of which become progenitors that regenerate the liver epithelial compartment after PH. Hence, scarring is a component of successful liver regeneration.

Evidence that two distinct crypt cell types secrete chloride and potassium in human colon

BACKGROUND

Human colon may secrete substantial amounts of water secondary to chloride (Cl(-)) and/or potassium (K(+)) secretion in a variety of diarrhoeal diseases. Ion secretion occurs via Cl(-) and K(+) channels, which are generally assumed to be co-located in the colonocyte apical membrane, although their exact cellular sites remain unclear.

OBJECTIVE

 To investigate the location of apical Cl(-) (CFTR) and apical K(+) (large conductance; BK) channels within human colonic epithelium.

DESIGN

Whole-cell patch clamp recordings were obtained from intact human colonic crypts. Specific blockers of K(+) channels and CFTR identified different types of K(+) channel and CFTR under resting conditions and after stimulating intracellular cAMP with forskolin. The BK channel β3-subunit was localised by immunostaining.

RESULTS

Two types of crypt cells were identified. One (73% of cells) had whole-cell currents dominated by intermediate conductance (IK) K(+) channels under resting conditions, which developed large CFTR-mediated currents in response to increasing intracellular cAMP. The other (27% of cells) had resting currents dominated by BK channels inhibited by the BK channel blocker penitrem A, but insensitive to both forskolin and the IK channel blocker clotrimazole. Immunostaining showed co-localisation of the BK channel β3-subunit and the goblet cell marker, MUC2.

CONCLUSIONS

In human colon, Cl(-) secretion originates from the dominant population of colonocytes expressing apical CFTR, whereas K(+) secretion is derived from a smaller population of goblet cells expressing apical BK channels. These findings provide new insights into the pathophysiology of secretory diarrhoea and should be taken into account during the development of anti-diarrhoeal drugs.

Molecular interplay between Δ5/Δ6 desaturases and long-chain fatty acids in the pathogenesis of non-alcoholic steatohepatitis

OBJECTIVE

The mechanisms underlying non-alcoholic steatohepatitis (NASH) are not completely elucidated. In the current study we integrated gene expression profiling of liver biopsies from NASH patients with translational studies in mouse models of steatohepatitis and pharmacological interventions in isolated hepatocytes to identify new molecular targets in NASH.

DESIGN AND RESULTS

Using oligonucleotide microarray analysis we identified a significant enrichment of genes involved in the multi-step catalysis of long-chain polyunsaturated fatty acids, namely, Δ-5 desaturase (Δ5D) and Δ6D in NASH. Increased expression of Δ5D and Δ6D at both mRNA and protein level were confirmed in livers from mice with high-fat diet-induced obesity and NASH. Gas chromatography analysis revealed impaired desaturation fluxes toward the ω-6 and ω-3 pathways resulting in increased ω-6 to ω-3 ratio and reduced ω-3 index in human and mouse fatty livers. Restoration of hepatic ω-3 content in transgenic fat-1 mice expressing an ω-3 desaturase, which allows the endogenous conversion of ω-6 into ω-3 fatty acids, produced a significant reduction in hepatic insulin resistance, steatosis, macrophage infiltration, necroinflammation and lipid peroxidation, accompanied by attenuated expression of genes involved in inflammation, fatty acid uptake and lipogenesis. These results were mostly reproduced by feeding obese mice with an exogenous ω-3-enriched diet. A combined Δ5D/Δ6D inhibitor, CP-24879, significantly reduced intracellular lipid accumulation and inflammatory injury in hepatocytes. Interestingly, CP-24879 exhibited superior antisteatotic and anti-inflammatory actions in fat-1 and ω-3-treated hepatocytes.

CONCLUSIONS

These findings indicate that impaired hepatic fatty acid desaturation and unbalanced ω-6 to ω-3 ratio play a role in the pathogenesis of NASH.

Systematic analysis of funding awarded for mycology research to institutions in the UK, 1997-2010

OBJECTIVES

Fungal infections cause significant global morbidity and mortality. We have previously described the UK investments in global infectious disease research, and here our objective is to describe the investments awarded to UK institutions for mycology research and outline potential funding gaps in the UK portfolio.

DESIGN

Systematic analysis.

SETTING

UK institutions carrying out infectious disease research.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome is the amount of funding and number of studies related to mycology research. Secondary outcomes are describing the investments made to specific fungal pathogens and diseases, and also the type of science along the R&D value chain.

METHODS

We systematically searched databases and websites for information on research studies from public and philanthropic funding institutions awarded between 1997 and 2010, and highlighted the mycology-related projects.

RESULTS

Of 6165 funded studies, we identified 171 studies related to mycology (total investment £48.4 million, 1.9% of all infection research, with mean annual funding £3.5 million). Studies related to global health represented 5.1% of this funding (£2.4 million, compared with 35.6% of all infectious diseases). Leading funders were the Biotechnology and Biological Sciences Research Council (£14.8 million, 30.5%) and Wellcome Trust (£12.0 million, 24.7%). Preclinical studies received £42.2 million (87.3%), with clinical trials, intervention studies and implementation research in total receiving £6.2 million (12.7%). By institution, University of Aberdeen received most funding (£16.9 million, 35%). Studies investigating antifungal resistance received £1.5 million (3.2%).

CONCLUSIONS

There is little translation of preclinical research into clinical trials or implementation research in spite of substantial disease burden globally, and there are few UK institutions that carry out significant quantities of mycology research of any type. In the context of global health and the burden of disease in low-income countries, more investment is required for mycology research.