Better translation via collaboration: The MRC National Mouse Genetics Network

The MRC National Mouse Genetics Network (NMGN) has been established in the UK to bring together researchers from academia and industry across the country from a wide range of disease areas and research backgrounds to rapidly facilitate clinical translation of mouse research findings and foster an environment of interdisciplinary learning.

Protocol for a randomized controlled trial of medically tailored meals compared to usual care among individuals with type 2 diabetes in Australia

BACKGROUND

'Food is medicine' strategies aim to integrate food-based nutrition interventions into healthcare systems and are of growing interest to healthcare providers and policy makers. 'Medically Tailored Meals' (MTM) is one such intervention, which involves the 'prescription' by healthcare providers of subsidized, pre-prepared meals for individuals to prevent or manage chronic conditions, combined with nutrition education.

OBJECTIVE

This study will test the efficacy of an MTM program in Australia among participants with type 2 diabetes (T2D) and hyperglycemia, who experience difficulties accessing and eating nutritious food.

METHODS

This study will be a two-arm parallel trial (goal n = 212) with individuals randomized in a 1:1 ratio to a MTM intervention group or a control group (106 per arm). Over 26 weeks, the intervention group will be prescribed 20 MTM per fortnight and up to 3 sessions with an accredited dietitian. Controls will continue with their usual care. The primary outcome is glycated hemoglobin (HbA1c, %) and secondary outcomes include differences in blood pressure, blood lipids and weight, all measured at 26 weeks. Process and economic data will be analyzed to assess the feasibility, acceptability, scalability, and cost-effectiveness of the intervention. Recruitment commenced in the first quarter of 2023, with analyses and results anticipated to be available by March 2025.

DISCUSSION

Few randomized controlled trials have assessed the impact of MTM on clinical outcomes. This Australian-first trial will generate robust data to inform the case for sustained, large-scale implementation of MTM to improve the management of T2D among vulnerable populations.

ANZCTR

ACTRN12622000852752.

PROTOCOL VERSION

Version 1.1, July 2023.

Asia-Pacific Perspectives on the Role of Continuous Glucose Monitoring in Optimizing Diabetes Management

Diabetes is prevalent, and it imposes a substantial public health burden globally and in the Asia-Pacific (APAC) region. The cornerstone for optimizing diabetes management and treatment outcomes is glucose monitoring, the techniques of which have evolved from self-monitoring of blood glucose (SMBG) to glycated hemoglobin (HbA1c), and to continuous glucose monitoring (CGM). Contextual differences with Western populations and limited regionally generated clinical evidence warrant regional standards of diabetes care, including glucose monitoring in APAC. Hence, the APAC Diabetes Care Advisory Board convened to gather insights into clinician-reported CGM utilization for optimized glucose monitoring and diabetes management in the region. We discuss the findings from a pre-meeting survey and an expert panel meeting regarding glucose monitoring patterns and influencing factors, patient profiles for CGM initiation and continuation, CGM benefits, and CGM optimization challenges and potential solutions in APAC. While CGM is becoming the new standard of care and a useful adjunct to HbA1c and SMBG globally, glucose monitoring type, timing, and frequency should be individualized according to local and patient-specific contexts. The results of this APAC survey guide methods for the formulation of future APAC-specific consensus guidelines for the application of CGM in people living with diabetes.

Diabetes-related foot disease: new insights with an Antipodean focus

Diabetes-related foot disease (DFD), defined as ulceration, infection, or destruction of tissues of the foot in a person with current or previously diagnosed diabetes mellitus, is associated with a heavy burden for both patients and the healthcare system with high morbidity, mortality and costs. Improved outcomes for people with DFD are achieved with an interdisciplinary approach and adherence to best practice clinical guidelines, however in the Australian context, the vastness of the country presents unique challenges in achieving optimal outcomes for all people with DFD, with variation in service delivery, availability and accessibility between metropolitan, rural and remote areas. Aboriginal and Torres Strait Islander Australians and people with diabetes living in rural and remote areas experience higher rates of lower extremity amputation and further efforts and resources are required to improve outcomes for these high risk groups. In recent years, there have been advances in knowledge, including the understanding of the pathogenesis of diabetes-related peripheral neuropathy, genetic polymorphisms and mechanisms of disease associated with acute Charcot neuroarthropathy, biomarkers and potential mediators of diabetes-related foot ulcer (DFU) healing, the microbiology and microbiome profile of DFUs, pressure assessment and management as well as an expanded understanding of DFU sequelae and comorbidities. In this review, we describe new insights into pathophysiology, sequelae and comorbidities of DFD with a focus on basic and translational aspects and contributions to the field from Australian and New Zealand DFD researchers.

Testing the Feasibility and Dietary Impact of a "Produce Prescription" Program for Adults with Undermanaged Type 2 Diabetes and Food Insecurity in Australia

BACKGROUND

There is growing interest in Food is Medicine programs that incorporate food-based interventions into health care for patients with diet-related conditions.

OBJECTIVES

We aimed to test the feasibility of a "produce prescription" program and its impact on diet quality for people with type 2 diabetes (T2D) experiencing food insecurity in Australia.

METHODS

We conducted a pre-post intervention study in n = 50 adults experiencing food insecurity with T2D and glycated hemoglobin (HbA1c) ≥8%. Once enrolled, participants received healthy food boxes weekly free of charge, with the contents sufficient to create 2 meals/d, 5 d/wk for the entire household, over 12 wk. Participants were also provided with tailored recipes and behavioral change support. The primary outcome was change in diet quality assessed by 24-h diet recalls. Secondary outcomes included differences in cardiovascular disease risk factors; blood micronutrients; and feasibility indicators. Differences in the baseline and 12-wk mean primary and secondary outcomes were assessed by paired t tests.

RESULTS

Participants were older adults with mean ± SD age 63 ± 9 y (range: 40-87 y), HbA1c 9.8% ± 1.5%, and 46% were female. Overall, 92% completed the final study follow-up for the primary outcome. Compared with baseline, diet quality improved at week 12, with an increase in the mean overall diet quality (Alternate Healthy Eating Index score) of 12.9 (95% CI: 8.7, 17.1; P < 0.001), driven by significant improvements in vegetables, fruits, whole grains, red/processed meat, trans fat, sodium, and alcohol consumption. Blood lipids also improved (total:HDL cholesterol: -0.48; 95% CI: -0.72, -0.24; P < 0.001), and there was significant weight loss (-1.74 kg; 95% CI: -2.80, -0.68 kg, P = 0.002), but no changes in other clinical outcomes. Participants reported high levels of satisfaction with the program.

CONCLUSIONS

These findings provide strong support for an adequately powered randomized trial to assess effects of produce prescription as an innovative approach to improve clinical management among individuals with T2D experiencing food insecurity. This trial was registered at https://anzctr.org.au/ as ACTRN12621000404820.

The Efficacy of Exercise Training for Cutaneous Microvascular Reactivity in the Foot in People with Diabetes and Obesity: Secondary Analyses from a Randomized Controlled Trial

It is unclear if cutaneous microvascular dysfunction associated with diabetes and obesity can be ameliorated with exercise. We investigated the effect of 12-weeks of exercise training on cutaneous microvascular reactivity in the foot. Thirty-three inactive adults with type 2 diabetes and obesity (55% male, 56.1 ± 7.9 years, BMI: 35.8 ± 5, diabetes duration: 7.9 ± 6.3 years) were randomly allocated to 12-weeks of either (i) moderate-intensity continuous training [50−60% peak oxygen consumption (VO2peak), 30−45 min, 3 d/week], (ii) low-volume high-intensity interval training (90% VO2peak, 1−4 min, 3 d/week) or (iii) sham exercise placebo. Post-occlusive reactive hyperaemia at the hallux was determined by laser-Doppler fluxmetry. Though time to peak flux post-occlusion almost halved following moderate intensity exercise, no outcome measure reached statistical significance (p > 0.05). These secondary findings from a randomised controlled trial are the first data reporting the effect of exercise interventions on cutaneous microvascular reactivity in the foot in people with diabetes. A period of 12 weeks of moderate-intensity or low-volume high-intensity exercise may not be enough to elicit functional improvements in foot microvascular reactivity in adults with type 2 diabetes and obesity. Larger, sufficiently powered, prospective studies are necessary to determine if additional weight loss and/or higher exercise volume is required.

AB0434 EFFICACY AND SAFETY OF OBINUTUZUMAB IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS WITH SECONDARY NON-RESPONSE TO RITUXIMAB

Background

Secondary inefficacy characterized by infusion reactions and anti-drug antibodies occur in 14% of SLE patients treated with repeat rituximab courses(1). Obinutuzumab is a next-generation humanized type-2 anti-CD20 therapy licensed for hematological malignancies which may overcome this issue(2).

Objectives

We set out to evaluate the clinical efficacy and safety of obinutuzumab in a cohort of rituximab resistant SLE patients.

Methods

We collated data from SLE patients receiving obinutuzumab for secondary non-response to rituximab in BILAG centres. Disease activity was assessed using BILAG-2004, SLEDAI-2K and serology before, and 6 months after, obinutuzumab 2x1000mg infusions alongside methylprednisolone 100mg. Flow cytometry where possible was carried out using a multiple gating highly sensitive strategy.

Results

All 9 patients included in the study received obinutuzumab alongside concomitant oral immunosuppression. At 6 months post-obinutuzumab, there were significant reductions in median SLEDAI-2K from 12 to 6 (p=0.014) and total BILAG-2004 score from 21 to 2 (p=0.009). Complement C3 and dsDNA titres improved significantly (both p=0.04). Non statistically significant numerical improvements were seen in C4 levels.

Of 8/9 patients receiving concomitant oral prednisolone at baseline (all >10mg/day), 5/9 had their dose reduced at 6 months; 4/8 were on 5mg/day and were in Lupus Low Disease Activity State. After obinutuzumab, 6/9 patients with peripheral B-cell data achieved complete depletion including 4/4 assessed with highly sensitive assays. 1/9 obinutuzumab non-responder required cyclophosphamide therapy. 1 unvaccinated patient died from COVID-19.

Table 1.

Baseline characteristics, disease activity and steroid doses before and after last obinutuzumab/rituximab.

PatientEthnicityDisease duration (Years)Age (Years)Total BILAG-2004 before ObiTotal BILAG-2004 after ObiSLEDAI-2K before ObiSLEDAI-2K after ObiPrednisolone before Obi (mg)Prednisolone after Obi (mg)1South Asian10.836.41821481052South Asian6.324.424212430103South Asian11.934.829110410104South Asian8.241.92116015155South Asian6.829.43221181450606White European17.537.0128881557White European16.930.01211281058Caribbean6.244.225213010159Caribbean2.621.092166105Median (Q1, Q3)NA8.2 (6, 12)34.8 (29,37)21 (12, 25)2 (1, 2)12 (10, 14)6 (4, 8)10 (10, 15)10 (5, 15)

Conclusion

Obinutuzumab appears to be effective and steroid-sparing in renal and non-renal SLE patients with secondary non-response to rituximab. Obinutuzumab was shown to be effective in patients with severe renal and non-renal disease. Therefore, in those with previous responsiveness to B-cell depletion, switching to humanised type-2 anti-CD20 therapy is a logical approach following loss off efficacy.

References

[1]Vital EM, Dass S, Buch MH, Henshaw K, Pease CT, Martin MF, et al. B cell biomarkers of rituximab responses in systemic lupus erythematosus. Arthritis Rheum [Internet]. 2011 Oct [cited 2020 Oct 12];63(10):3038–47. Available from: https://pubmed.ncbi.nlm.nih.gov/21618204/

[2]Hassan SU, Md Yusof MY, Emery P, Dass S, Vital EM. Biologic Sequencing in Systemic Lupus Erythematosus: After Secondary Non-response to Rituximab, Switching to Humanised Anti-CD20 Agent Is More Effective Than Belimumab. Front Med [Internet]. 2020 Aug 27 [cited 2020 Sep 2];7:498. Available from: https://www.frontiersin.org/article/10.3389/fmed.2020.00498/full

Disclosure of Interests

Jack Arnold: None declared, Shouvik Dass Consultant of: Roche, Abbvie, UCB & Chugai, Employee of: Honoraria from Roche, Abbvie, UCB & Chugai, Sarah Twigg: None declared, Colin Jones: None declared, Benjamin Rhodes: None declared, Peter Hewins: None declared, Mithun Chakravorty: None declared, Philip Courtney: None declared, Michael Ehrenstein Grant/research support from: GSK, Employee of: Has received honoraria from GSK, Md Yuzaiful Md Yusof: None declared, Edward Vital Employee of: Has received honoraria from Roche

Metabolite-based dietary supplementation in human type 1 diabetes is associated with microbiota and immune modulation

BACKGROUND

Short-chain fatty acids (SCFAs) produced by the gut microbiota have beneficial anti-inflammatory and gut homeostasis effects and prevent type 1 diabetes (T1D) in mice. Reduced SCFA production indicates a loss of beneficial bacteria, commonly associated with chronic autoimmune and inflammatory diseases, including T1D and type 2 diabetes. Here, we addressed whether a metabolite-based dietary supplement has an impact on humans with T1D. We conducted a single-arm pilot-and-feasibility trial with high-amylose maize-resistant starch modified with acetate and butyrate (HAMSAB) to assess safety, while monitoring changes in the gut microbiota in alignment with modulation of the immune system status.

RESULTS

HAMSAB supplement was administered for 6 weeks with follow-up at 12 weeks in adults with long-standing T1D. Increased concentrations of SCFA acetate, propionate, and butyrate in stools and plasma were in concert with a shift in the composition and function of the gut microbiota. While glucose control and insulin requirements did not change, subjects with the highest SCFA concentrations exhibited the best glycemic control. Bifidobacterium longum, Bifidobacterium adolescentis, and vitamin B7 production correlated with lower HbA1c and basal insulin requirements. Circulating B and T cells developed a more regulatory phenotype post-intervention.

CONCLUSION

Changes in gut microbiota composition, function, and immune profile following 6 weeks of HAMSAB supplementation were associated with increased SCFAs in stools and plasma. The persistence of these effects suggests that targeting dietary SCFAs may be a mechanism to alter immune profiles, promote immune tolerance, and improve glycemic control for the treatment of T1D.

TRIAL REGISTRATION

ACTRN12618001391268. Registered 20 August 2018, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375792 Video Abstract.

Body Composition in Young Adults Living With a Fontan Circulation: The Myopenic Profile

Background

We sought to characterize body composition abnormalities in young patients living with a Fontan circulation and explore potential pathophysiologic associations.

Methods and Results

Twenty‐eight patients with a Fontan circulation were prospectively recruited in this cross‐sectional study. Participants underwent cardiopulmonary exercise testing, dual‐energy X‐ray absorptiometry, echocardiography, and biochemical assessment. Mean age was 26±7 years. Skeletal muscle mass, estimated by appendicular lean mass index Z score, was reduced compared with reference data (−1.49±1.10, P<0.001). Percentage body fat Z score overall was within normal range (0.23±1.26, P=0.35), although 46% had elevated adiposity. Those with reduced skeletal muscle mass (appendicular lean mass index Z score of −1 or lower) had lower percent predicted oxygen pulse (55±15 versus 76±16%, P=0.002). Overall agreement between body mass index and dual‐energy X‐ray absorptiometry to assess adiposity was fair only (weighted [linear] κ coefficient: 0.53; 95% CI, 0.34–0.73) and slight in the setting of muscle mass deficiency (weighted κ coefficient: 0.32; 95% CI, 0.13–0.50). Appendicular lean mass was independently associated with absolute peak VO₂ (β=70.6 mL/min, P=0.001). Appendicular lean mass index Z score was inversely associated with hemoglobin (r=−0.4, P=0.04), and the degree of muscle deficit was associated with ventricular systolic impairment.

Conclusions

Young patients with a Fontan circulation have a body composition characterized by reduced skeletal muscle mass, which is associated with peak exercise capacity. Increased adiposity is common despite a normal body mass index. Low skeletal muscle mass is associated with systolic dysfunction and compensatory erythrocytosis.

Amount and Type of Dietary Fat, Postprandial Glycemia, and Insulin Requirements in Type 1 Diabetes: A Randomized Within-Subject Trial

OBJECTIVE

The American Diabetes Association recommends individuals with type 1 diabetes (T1D) adjust insulin for dietary fat; however, optimal adjustments are not known. This study aimed to determine 1) the relationship between the amount and type of dietary fat and glycemia and 2) the optimal insulin adjustments for dietary fat.

RESEARCH DESIGN AND METHODS

Adults with T1D using insulin pump therapy attended the research clinic on 9-12 occasions. On the first six visits, participants consumed meals containing 45 g carbohydrate with 0 g, 20 g, 40 g, or 60 g fat and either saturated, monounsaturated, or polyunsaturated fat. Insulin was dosed using individual insulin/carbohydrate ratio as a dual-wave 50/50% over 2 h. On subsequent visits, participants repeated the 20-60-g fat meals with the insulin dose estimated using a model predictive bolus, up to twice per meal, until glycemic control was achieved.

RESULTS

With the same insulin dose, increasing the amount of fat resulted in a significant dose-dependent reduction in incremental area under the curve for glucose (iAUC_glucose) in the early postprandial period (0-2 h; P = 0.008) and increase in iAUC_glucose in the late postprandial period (2-5 h; P = 0.004). The type of fat made no significant difference to the 5-h iAUC_glucose. To achieve glycemic control, on average participants required dual-wave insulin bolus: for 20 g fat, +6% insulin, 74/26% over 73 min; 40 g fat, +6% insulin, 63/37% over 75 min; and 60 g fat, +21% insulin, 49/51% over 105 min.

CONCLUSIONS

This study provides clinical guidance for mealtime insulin dosing recommendations for dietary fat in T1D.

OR18-2 Higher Plasma Estradiol Concentration Is Independently Associated with Lower Biological Age, Assessed as Leucocyte Telomere Length, in Older Men

Telomeres are essential DNA-protein complexes comprising TTAGGG repeats binding specific proteins, which protect the physical ends of chromosomes from fusion and degradation. Attrition of telomeres results in cellular senescence. Leucocyte telomere length (LTL) reflects lengths of telomeres in various tissues, and shorter LTL is a marker of advancing biological age. Previous work has associated bioactive metabolites of T, dihydrotestosterone (DHT) and estradiol (E2) with LTL in a population of predominantly middle-aged men [1]. However, the relationship of these hormones to biological age in older men was unclear. We aimed to clarify associations of sex hormones with LTL in a cohort of 2,913 community-dwelling men aged 70-89 years. Early morning blood samples were assayed for T, DHT and E2 using mass spectrometry, and for sex hormone-binding globulin (SHBG) using immunoassay. LTL was measured using a multiplex quantitative PCR method and expressed as the amount of telomeric DNA relative to beta-globin, a single copy control gene (T/S ratio). Cross-sectional analyses utilised multivariable linear regression. Mean (±SD) age was 76.7±3.2 years. The average difference per decade of age was T -0.46 nmol/L, DHT -0.11 nmol/L, E2 -7.5 pmol/L, SHBG +10.2 nmol/L, and LTL (T/S ratio) -0.065. E2 correlated with T/S ratio (r=0.038, p=0.039). After excluding highest and lowest 1% of values, the correlation between E2 and T/S ratio was largely unchanged (r=0.039, p=0.037). SHBG was inversely correlated with T/S ratio (r=-0.053, p=0.004), also unchanged in the trimmed analysis (r=-0.055, p=0.004.) After adjusting for age, BMI, cardiovascular disease, diabetes, alcohol, smoking, physical activity, lipids and hypertension, E2 remained associated with T/S ratio (per 1 SD increase E2: coefficient 0.011, p=0.043). When E2 and SHBG were simultaneously included in the multivariate model, E2 remained positively associated with T/S ratio (coefficient 0.014, p=0.014) and SHBG inversely associated (coefficient -0.013, p=0.037). The magnitude of increase in T/S ratio associated with a 1 SD higher plasma E2 concentration was comparable with having a BMI 3.6 kg/m² lower, and two thirds that associated with being 3.6 years younger. T, DHT and LH were not associated with LTL in multivariate analyses. To conclude, in older men, neither T nor DHT are associated with LTL while E2 is independently associated with LTL and SHBG is inversely associated. These findings associate activity of the gonadal axis with lower biological age in older men. However, causality cannot be inferred from an observational, cross-sectional study, thus additional research is necessary to determine whether sex hormone exposure modulates male biological ageing. Reference: [1] Yeap BB, et al. J Clin Endocrinol Metab 2016; 101: 1299-1306.

Glucocorticoids differentially inhibit expression of the RET proto-oncogene

The RET proto-oncogene encodes a receptor tyrosine kinase activated by the binding of factors from the glial cell line-derived neurotrophic factor (GDNF) family to receptor-alpha components such as GDNF family receptor alpha-1 (GFR alpha-1). Mutations within the sequence of the RET proto-oncogene are associated with multiple endocrine neoplasia type 2 (MEN 2), an inherited tumor syndrome characterized by the development of medullary thyroid carcinoma (MTC) and other neuroendocrine tumors. Despite Northern analysis showing that RET is expressed in the majority of MTCs, the factors regulating this expression are poorly understood. To address this issue we examined RET expression in response to glucocorticoids in the TT cell line, derived from a metastatic MTC. The synthetic glucocorticoid dexamethasone was found to reduce RET expression at both mRNA and protein levels. This effect was dose responsive and maximal at 24 h. The reduction in RET mRNA was shown to be specific to glucocorticoids and was also seen in a primary MTC culture. Nuclear run-on studies revealed the reduction in steady-state RNA to be due to a decrease in RET mRNA transcription and the effect was shown to be independent of new protein synthesis or RNA stability. Dexamethasone was also found to exert an inhibitory effect upon cell growth, suggesting a potential use for glucocorticoids in the treatment of medullary carcinoma and MEN 2.

Screening for Celiac Disease in Type 1 Diabetes: A Systematic Review

BACKGROUND AND OBJECTIVES

Prevalence rates of type 1 diabetes (T1D) and celiac disease (CD) vary from 1.6% to 16.4% worldwide. Screening guidelines are variable and not evidence based. Our aim was to conduct a systematic review of CD in T1D.

METHODS

Medline, Embase, and the Cochrane Library were searched. Studies were limited to those in English and in humans. We selected longitudinal cohort studies screening for CD in T1D with at least 5 years of follow-up. Screening rates, characteristics, and prevalence of biopsy-proven CD in people with T1D were extracted.

RESULTS

We identified 457 nonduplicate citations; 48 were selected for full-text review. Nine longitudinal cohort studies in 11,157 children and adolescents with 587 cases of biopsy-proven CD met the inclusion criteria. Median follow-up was 10 years (range: 5-18 years). The weighted pooled prevalence of CD was 5.1% (95% confidence interval: 3.1-7.4%). After excluding 41 cases with CD onset before T1D, CD was diagnosed in 218 of 546 (40%) subjects within 1 year, in 55% within 2 years, and in 79% within 5 years of diabetes duration. Two studies (478 cases) reported higher rates of CD in children aged <5 years at T1D diagnosis. The duration of follow-up varied across the included studies. CD screening frequency progressively decreased with increased T1D duration.

CONCLUSIONS

Because most cases of CD are diagnosed within 5 years of T1D diagnosis, screening should be considered at T1D diagnosis and within 2 and 5 years thereafter. CD screening should be considered at other times in patients with symptoms suggestive of CD. More research is required to determine the screening frequency beyond 5 years of diabetes duration.

Chronic erythropoietin treatment improves diet-induced glucose intolerance in rats

Erythropoietin (EPO) ameliorates glucose metabolism through mechanisms not fully understood. In this study, we investigated the effect of EPO on glucose metabolism and insulin signaling in skeletal muscle. A 2-week EPO treatment of rats fed with a high-fat diet (HFD) improved fasting glucose levels and glucose tolerance, without altering total body weight or retroperitoneal fat mass. Concomitantly, EPO partially rescued insulin-stimulated AKT activation, reduced markers of oxidative stress, and restored heat-shock protein 72 expression in soleus muscles from HFD-fed rats. Incubation of skeletal muscle cell cultures with EPO failed to induce AKT phosphorylation and had no effect on glucose uptake or glycogen synthesis. We found that the EPO receptor gene was expressed in myotubes, but was undetectable in soleus. Together, our results indicate that EPO treatment improves glucose tolerance but does not directly activate the phosphorylation of AKT in muscle cells. We propose that the reduced systemic inflammation or oxidative stress that we observed after treatment with EPO could contribute to the improvement of whole-body glucose metabolism.

Reduction of ARNT in myeloid cells causes immune suppression and delayed wound healing

Aryl hydrocarbon receptor nuclear translocator (ARNT) is a transcription factor that binds to partners to mediate responses to environmental signals. To investigate its role in the innate immune system, floxed ARNT mice were bred with lysozyme M-Cre recombinase animals to generate lysozyme M-ARNT (LAR) mice with reduced ARNT expression. Myeloid cells of LAR mice had altered mRNA expression and delayed wound healing. Interestingly, when the animals were rendered diabetic, the difference in wound healing between the LAR mice and their littermate controls was no longer present, suggesting that decreased myeloid cell ARNT function may be an important factor in impaired wound healing in diabetes. Deferoxamine (DFO) improves wound healing by increasing hypoxia-inducible factors, which require ARNT for function. DFO was not effective in wounds of LAR mice, again suggesting that myeloid cells are important for normal wound healing and for the full benefit of DFO. These findings suggest that myeloid ARNT is important for immune function and wound healing. Increasing ARNT and, more specifically, myeloid ARNT may be a therapeutic strategy to improve wound healing.

Direct observation of ion distributions near electrodes in ionic polymer actuators containing ionic liquids

The recent boom of energy storage and conversion devices, exploiting ionic liquids (ILs) to enhance the performance, requires an in-depth understanding of this new class of electrolytes in device operation conditions. One central question critical to device performance is how the mobile ions accumulate near charged electrodes. Here, we present the excess ion depth profiles of ILs in ionomer membrane actuators (Aquivion/1-butyl-2,3-dimethylimidazolium chloride (BMMI-Cl), 27 μm thick), characterized directly by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) at liquid nitrogen temperature. Experimental results reveal that for the IL studied, cations and anions are accumulated at both electrodes. The large difference in the total volume occupied by the excess ions between the two electrodes cause the observed large bending actuation of the actuator. Hence we demonstrate that ToF-SIMS experiment provides great insights on the physics nature of ionic devices.

A randomized controlled pilot trial comparing the impact of access to clinical endocrinology video demonstrations with access to usual revision resources on medical student performance of clinical endocrinology skills

BACKGROUND

Demonstrating competence in clinical skills is key to course completion for medical students. Methods of providing clinical instruction that foster immediate learning and potentially serve as longer-term repositories for on-demand revision, such as online videos demonstrating competent performance of clinical skills, are increasingly being used. However, their impact on learning has been little studied. The aim of this study was to determine the value of adjunctive on-demand video-based training for clinical skills acquisition by medical students in endocrinology.

METHODS

Following an endocrinology clinical tutorial program, 2nd year medical students in the pre-assessment revision period were recruited and randomized to either a set of bespoke on-line clinical skills training videos (TV), or to revision as usual (RAU). The skills demonstrated on video were history taking in diabetes mellitus (DMH), examination for diabetes lower limb complications (LLE), and examination for signs of thyroid disease (TE). Students were assessed on these clinical skills in an observed structured clinical examination two weeks after randomization. Assessors were blinded to student randomization status.

RESULTS

For both diabetes related clinical skills assessment tasks, students in the TV group performed significantly better than those in the RAU group. There were no between group differences in thyroid examination performance. For the LLE, 91.7% (n = 11/12) of students randomized to the video were rated globally as competent at the skill compared with 40% (n = 4/10) of students not randomized to the video (p = 0.024). For the DMH, 83.3% (n = 10/12) of students randomized to the video were rated globally as competent at the skill compared with 20% (n = 2/10) of students not randomized to the video (p = 0.007).

CONCLUSION

Exposure to high quality videos demonstrating clinical skills can significantly improve medical student skill performance in an observed structured clinical examination of these skills, when used as an adjunct to clinical skills face-to-face tutorials and deliberate practice of skills in a blended learning format. Video demonstrations can provide an enduring, on-demand, portable resource for revision, which can even be used at the bedside by learners. Such resources are cost-effectively scalable for large numbers of learners.

CCN2 plays a key role in extracellular matrix gene expression in severe hypertrophic cardiomyopathy and heart failure

Hypertrophic cardiomyopathy (HCM) is the most common inherited primary myocardial disorder. HCM is characterized by interstitial fibrosis and excessive accumulation of extracellular matrix (ECM) proteins. Fibrosis in HCM has been associated with impaired cardiac function and heart failure, and has been considered a key substrate for ventricular arrhythmias and sudden death. The molecular triggers underpinning ECM production are not well established. We have previously developed a double-mutant mouse model of HCM that recapitulates the phenotype seen in humans with multiple mutations, including earlier onset of the disease, progression to a dilated phenotype, severe heart failure and premature mortality. The present study investigated the expression of ECM-encoding genes in severe HCM and heart failure. Significant upregulation of structural Fn1, regulatory Mmp14, Timp1, Serpin3A, SerpinE1, SerpineE2, Tgfβ1, and Tgfβ2; and matricellular Ccn2, Postn, Spp1, Thbs1, Thbs4, and Tnc was evident from the early, pre-phenotype stage. Non-myocytes expressed ECM genes at higher levels than cardiomyocytes in normal and diseased hearts. Synchronous increase of secreted CCN2 and TIMP1 plasma levels and decrease of MMP3 levels were observed in end-stage disease. CCN2 protein expression was increased from early disease in double-mutant hearts and played an important role in ECM responses. It was a powerful modulator of ECM regulatory (Timp1 and SerpinE1) and matricellular protein-encoding (Spp1, Thbs1, Thbs4 and Tnc) gene expression in cardiomyocytes when added exogenously in vitro. Modulation of CCN2 (CTGF, connective tissue growth factor) and associated early ECM changes may represent a new therapeutic target in the treatment and prevention of heart failure in HCM.

Lymphocoele of the thoracic duct: a cause of left supraclavicular fossa

Lymphocoele of the thoracic duct, alternatively referred to as thoracic duct cyst, is an uncommon abnormality that can present occasionally as a left supraclavicular fossa mass. Recognition of the origin of such a neck mass on imaging is crucial to avert unnecessary intervention. A case of such a mass is presented with discussion of the fascinating variable anatomy of the thoracic duct.

Imaging assessment of penetrating craniocerebral and spinal trauma

Craniocerebral and spinal penetrating trauma, which may be either missile (most typically gun-related) or non-missile (most typically knife-related), is becoming an increasingly common presentation to the urban general and specialized radiology service in the UK. These injuries carry significant morbidity and mortality with a number of criteria for prognosis identifiable on cross-sectional imaging. Potential complications can also be pre-empted by awareness of certain neuroradiological features. Not all of these injuries are criminal in origin, however, a significant proportion will be, requiring, on occasion, provision of both ante-mortem and post-mortem radiological opinion to the criminal investigative procedure. This review aims to highlight certain imaging features of penetrating craniocerebral and spinal trauma including important prognostic, therapeutic, and forensic considerations.

The use of extracorporeal carbon dioxide removal in the management of life-threatening bronchospasm due to influenza infection

We report the use of the Novalung interventional Lung Assist extracorporeal carbon dioxide removal device, (Novalung GmbH, Lotzenacker 3, D-72379 Hechingen, Germany) to treat a 46-year-old female with life-threatening bronchospasm secondary to influenza infection. Despite maximal treatment she developed severe hypercapnia and acidosis. The necessity for high inflation pressures led to the development of gross surgical emphysema. Use of the interventional Lung Assist enabled a rapid correction of hypercapnoea and acidosis, allowing a reduction in airway pressures, reducing further barotrauma. Subsequent resolution of the inflammatory process allowed removal of the interventional Lung Assist after 11 days. She was successfully weaned from mechanical ventilation and made a full recovery.

The differential regulation of Smad7 in kidney tubule cells by connective tissue growth factor and transforming growth factor-beta1

AIMS

Smad7 is an inhibitory Smad that regulates transforming growth factor-beta (TGF-beta) signaling. Connective tissue growth factor (CTGF) is recognized as a potent downstream mediator of the fibrogenic effects of TGF-beta1. SMAD binding sites have been identified in both TGF-beta and CTGF promoters. The effect of CTGF on Smad7 expression and its role in the regulation of Smad7 induced by TGF-beta1 in renal tubular cells is unknown.

METHODS

Human model of proximal tubular cells (HK-2 cells) was used and confirmed using a diabetic rat model. RT-PCR was performed to measure Smad7, TGF-beta1 and Smad2 and ELISA was performed to measure active TGF-beta1. CTGF or TGF-beta1 was silenced in HK-2 cells using siRNA methodology.

RESULTS

TGF-beta1 induced Smad7 in a time-dependent manner, peaking at 30 min (P<0.0005) but sustained up to 24 hrs (p<0.005). Conversely, CTGF reduced Smad7, which was maximal at 24 hrs (p<0.05). This was supported by our in vivo data demonstrating that CTGF protein significantly increased while Smad7 mRNA level was reduced in a diabetic rat model. The basal expression level of Smad7 decreased in TGF-beta1 silenced cells compared to cells transfected with non-specific siRNA (p<0.0005). The basal expression level of Smad7 increased in CTGF silenced cells (p<0.05), which was increased by TGF-beta1 (p<0.005). Both mRNA and protein levels of TGF-beta1 decreased in CTGF silenced cells (p<0.05 and p<0.005 respectively) accompanied by reduction in Smad2 mRNA level in CTGF silenced cells.

CONCLUSIONS

Smad7 is induced rapidly by TGF-beta1 limiting the response to TGF-beta1. CTGF likely plays a key role in promoting TGF-beta1 activity by decreasing the availability of Smad7 and increasing Smad2.

Transforming growth factor-beta1 differentially mediates fibronectin and inflammatory cytokine expression in kidney tubular cells

Transforming growth factor-beta(1) (TGF-beta(1)) is not only an important fibrogenic but also immunomodulatory cytokine in the human kidney. We have recently demonstrated that TGF-beta(1) induces interleukin-8 (IL-8), macrophage chemoattractant protein-1 (MCP-1), and fibronectin production in renal proximal tubular (HK-2) cells. However, the unique dependence of IL-8, MCP-1, and fibronectin on TGF-beta(1) expression is unknown. The TGF-beta(1) gene was effectively silenced in HK-2 cells using small-interference (si) RNA. Basal secretion of IL-8 and MCP-1 decreased (both P < 0.05) but, paradoxically, fibronectin increased (P < 0.05) in TGF-beta(1)-silenced cells compared with cells transfected with nonspecific siRNA. Significant increases were observed in mRNA for the TGF-beta(2) (P < 0.05), TGF-beta(3) (P < 0.05) isoforms and pSmad2 (P < 0.05), which were reflected in protein expression. Concurrent exposure to pan-specific TGF-beta antibody reversed the observed increase in fibronectin expression, suggesting that TGF-beta(2) and TGF-beta(3) isoforms mediate the increased fibronectin expression in TGF-beta(1)-silenced cells. An increase in the DNA binding activity of activator protein-1 (AP-1; P < 0.05) was also observed in TGF-beta(1)-silenced cells. In contrast, nuclear factor-kappaB (NF-kappaB) DNA binding activity was significantly decreased (P < 0.0005). These studies demonstrate that TGF-beta(1) is a key regulator of IL-8 and MCP-1, whereas fibronectin expression is regulated by a complex interaction between the TGF-beta isoforms in the HK-2 proximal tubular cell line. Decreased expression of TGF-beta(1) reduces chemokine production in association with reduced NF-kappaB DNA binding activity, suggesting that immunomodulatory pathways in the kidney are specifically dependent on TGF-beta(1). Conversely, decreased expression of TGF-beta(1) results in increased TGF-beta(2), TGF-beta(3), AP-1, and pSmad2 that potentially mediates the observed increase in fibronectin.

Tranilast attenuates connective tissue growth factor-induced extracellular matrix accumulation in renal cells

Tranilast (N-[3,4-dimethoxycinnamoyl]anthranilic acid) is a synthetic compound that we have recently reported to inhibit transforming growth factor-beta1 (TGF-beta1)-induced tubulointerstitial fibrosis in the kidney. Connective tissue growth factor (CTGF) is recognized as a potent downstream mediator of TGF-beta1. Both proximal tubule cells (PTCs) and cortical fibroblasts (CFs) are considered to be responsible for the production of tubulointerstitial extracellular matrix (ECM). These studies were undertaken to assess the profibrotic effects of CTGF in an in vitro model of the human PTCs and CFs, and to determine whether tranilast is effective in limiting the in vitro matrix responses induced by CTGF. Primary cultures of PTCs and CFs were exposed to CTGF (20 ng/ml)+/-tranilast (100 microM). Cell hypertrophy and the secretion of the ECM proteins fibronectin and collagen IV were determined. The effects of tranilast on TGF-beta1-induced CTGF mRNA expression and on phosphorylation of Smad2 were determined. CTGF significantly induced cell hypertrophy, increased fibronectin, and collagen IV secretion in PTCs and CFs. In all cases, the CTGF-induced increase in ECM protein was inhibited in the presence of tranilast. Tranilast reduced CTGF mRNA and phosphorylation of Smad2, which were induced by TGF-beta1 in PTCs and CFs. These results suggest that tranilast is a potential effective antifibrotic compound in the kidney, exerting its effects via inhibition of TGF-beta1-induced CTGF expression and downstream activation of the Smad2 pathway in both PTCs and CFs.

TGF-beta1 induces IL-8 and MCP-1 through a connective tissue growth factor-independent pathway

Transforming growth factor-beta(1) (TGF-beta(1)) functions as an important immunomodulatory cytokine in human kidney. Evidence suggests that connective tissue growth factor (CTGF) is an important downstream mediator of the profibrotic effects of TGF-beta(1). However, the role of CTGF in TGF-beta(1)-induced chemokine production remains unknown. This study was undertaken to determine whether CTGF is involved in mediating TGF-beta(1)-induced chemokine production in renal proximal tubular (HK-2) cells. Interleukin-8 (IL-8) and macrophage chemoattractant protein-1 (MCP-1) were measured. TGF-beta(1) induced an increase in IL-8 and MCP-1 (both P < 0.05) compared with control levels. CTGF was effectively silenced using small interference RNA (siRNA) in HK-2 cells. RT-PCR and real-time PCR confirmed a 94% reduction in CTGF mRNA. In the CTGF-silenced cells, TGF-beta(1)-stimulated IL-8 and MCP-1 secretion was not altered compared with control cells. Similarly, basal secretion of IL-8 and MCP-1 was not changed in CTGF-silenced cells. The direct effect of CTGF (20, 200, and 400 ng/ml) on IL-8 and MCP-1 was assessed at 24-, 48-, and 72-h time points and no stimulation was observed. Our studies further demonstrate that in the CTGF gene-silenced cells, CTGF partially mediates TGF-beta(1)-induced fibronectin and collagen IV secretion. These data suggest that TGF-beta(1) induced IL-8 and MCP-1 via CTGF-independent pathway. TGF-beta mediates both fibrosis and chemokine production in the proximal tubule of the kidney. However, CTGF plays a more specific role as a downstream mediator of TGF-beta(1)-induced fibrosis.

Integrated actions of transforming growth factor-beta1 and connective tissue growth factor in renal fibrosis

Matrix accumulation in the renal tubulointerstitium is predictive of a progressive decline in renal function. Transforming growth factor-beta(1) (TGF-beta(1)) and, more recently, connective tissue growth factor (CTGF) are recognized to play key roles in mediating the fibrogenic response, independently of the primary renal insult. Further definition of the independent and interrelated effects of CTGF and TGF-beta(1) is critical for the development of effective antifibrotic strategies. CTGF (20 ng/ml) induced fibronectin and collagen IV secretion in primary cultures of human proximal tubule cells (PTC) and cortical fibroblasts (CF) compared with control values (P < 0.005 in all cases). This effect was inhibited by neutralizing antibodies to either TGF-beta or to the TGF-beta type II receptor (TbetaRII). TGF-beta(1) induced a greater increase in fibronectin and collagen IV secretion in both PTC (P < 0.01) and CF (P < 0.01) compared with that observed with CTGF alone. The combination of TGF-beta(1) and CTGF was additive in their effects on both PTC and CF fibronectin and collagen IV secretion. TGF-beta(1) (2 ng/ml) stimulated CTGF mRNA expression within 30 min, which was sustained for up to 24 h, with a consequent increase in CTGF protein (P < 0.05), whereas CTGF had no effect on TGF-beta(1) mRNA or protein expression. TGF-beta(1) (2 ng/ml) induced phosphorylated (p)Smad-2 within 15 min, which was sustained for up to 24 h. CTGF had a delayed effect on increasing pSmad-2 expression, which was evident at 24 h. In conclusion, this study has demonstrated the key dependence of the fibrogenic actions of CTGF on TGF-beta. It has further uniquely demonstrated that CTGF requires TGF-beta, signaling through the TbetaRII in both PTCs and CFs, to exert its fibrogenic response in this in vitro model.

Randomized crossover comparison of the ProSeal TM laryngeal mask airway with the Laryngeal Tube ® during anaesthesia with controlled ventilation

BACKGROUND

The Laryngeal Tube (LT) performs similarly to the classic laryngeal mask airway during controlled ventilation but with an improved airway seal. We compared the laryngeal tube with the ProSeal laryngeal mask airway (PLMA) throughout anaesthesia.

METHODS

Thirty-two patients were studied using a randomized cross-over design. The primary outcome measure was airway seal pressure. Secondary outcome measures included peak and plateau airway pressures, time to achieve an airway, ease of insertion, airway manipulations required to achieve a patent airway and grade of fibre-optic laryngoscopy. The proportion of patients in whom good, fair or failed ventilation was achieved was also calculated.

RESULTS

No significant difference was found in regard to seal pressure (PLMA, median 26.5 cm H2O, range 10-40; LT, median 24, range 6-40; P=0.7, 95% confidence interval of the difference 3.5 to -4.0). There were two failures of insertion or ventilation in the LT group and none in the PLMA group. The peak airway pressure with the PLMA was lower than with the LT but the difference was clinically unimportant (PLMA, mean 16.2 cm H2O, SD 3.52; LT, mean 17.9, SD 5.21; P=0.02, 95% confidence interval of the difference -3.1 to -0.28). The PLMA took significantly less time to insert than the LT (PLMA, median 18.5 s, interquartile range 14-26; LT, median 22, interquartile range 15-36.5; P<0.02, 95% confidence interval of the difference -21.5 to -1.0). The PLMA gave a significantly better view on fibre-optic laryngoscopy than the LT (P<0.001, 95% confidence interval of the difference in grade -2.0 to -1.0). In the 16 patients in whom the PLMA was used during maintenance of anaesthesia ventilation was good in 15, fair in none and failed in one. The equivalent figures for the LT were good in nine, fair in six and failed in one (P=0.009). There was no significant difference in the plateau airway pressure, ease of insertion of the devices, number of manipulations required to achieve or maintain an airway, or in overall complications.

CONCLUSION

The two devices performed equally well in terms of seal pressure. The PLMA was quicker to insert. Efficacy of ventilation was significantly better with the PLMA than the LT. The PLMA allowed a significantly better view of the larynx with a fibre-optic laryngoscope, and may therefore be of more use in cases where visualization of the larynx is required.

Vitamin D supplementation and bone mineral density in early postmenopausal women

BACKGROUND

Increased vitamin D intake may preserve or increase bone mineral density (BMD) in older persons.

OBJECTIVE

A 2-y double-blind study was undertaken to determine whether weekly administration of 10 000 units of vitamin D(2) maintained or increased BMD in younger postmenopausal women more efficiently than did calcium supplements alone.

DESIGN

One hundred eighty-seven women who were >or= 1 y postmenopausal were randomly assigned to take either 1000 mg Ca/d after the evening meal or 1000 mg Ca/d plus 10 000 U vitamin D(2)/wk in a double-blind, placebo-controlled format. The BMD of the proximal forearm, lumbar spine, femoral neck, Ward's triangle, and femoral trochanter was measured at 6-mo intervals by osteodensitometry.

RESULTS

During the 2-y period, there was no significant difference in the change in BMD at any site between the subjects taking calcium supplements and those taking calcium plus vitamin D(2). Both groups significantly (P < 0.005) gained BMD in Ward's triangle and the femoral trochanter but significantly (P < 0.005) lost bone in the proximal radius. There was no significant change in the lumbar spine or femoral neck BMD.

CONCLUSION

In younger postmenopausal women ( age: 56 y) whose average baseline serum 25-hydroxyvitamin D concentration was well within the normal range, the addition of 10 000 U vitamin D(2)/wk to calcium supplementation at 1000 mg/d did not confer benefits on BMD beyond those achieved with calcium supplementation alone.

Genetic analysis of lithium-associated parathyroid tumors

OBJECTIVE

The aim of this study was to determine the primary genetic events that may underlie the formation of parathyroid tumors in patients with lithium-associated hyperparathyroidism (HPT).

METHODS

Comparative genomic hybridization (CGH), loss of heterozygosity (LOH) and multiple endocrine neoplasia type 1 gene (MEN1) mutation analysis were used to analyze twelve parathyroid tumors from nine patients with lithium-associated HPT. For comparison, CGH was also carried out in a non-lithium-associated group of thirteen sporadic parathyroid tumors.

RESULTS

A higher prevalence of multiglandular disease in the lithium-associated HPT patients compared with the idiopathic sporadic patients was observed (Fisher's exact test, P=0.02). CGH alterations were detected in four lithium-associated parathyroid tumors, involving loss at 1p, 11, 15q, 22q and gain of the X chromosome. In addition, one of these four cases exhibited LOH at 11q13 and was found to contain a novel somatic MEN1 mutation (c.1193insTAC). Although fewer lithium-associated parathyroid tumors were shown to contain genetic alterations compared with the sporadic parathyroid tumors, the changes detected were those frequently associated with both familial and sporadic parathyroid tumorigenesis.

CONCLUSION

This is, to our knowledge, the first genetic analysis of parathyroid tumors in lithium-associated HPT patients. Our data indicated that the majority of lithium-associated parathyroid tumors do not contain gross chromosomal alterations and suggest that in most cases the tumorigenic pathway is independent of MEN1 and genes at 1p34.3-pter and 1q21-q32. It is possible that other discrete genetic alterations or epigenetic changes, not screened for in this study, could also be responsible for parathyroid tumorigenesis in lithium-associated HPT.

A prime-boost immunisation regimen using DNA followed by recombinant modified vaccinia virus Ankara induces strong cellular immune responses against the Plasmodium falciparum TRAP antigen in chimpanzees

Two chimpanzees were vaccinated intramuscularly against malaria using plasmid DNA expressing the pre-erythrocytic antigens thrombospondin related adhesion protein (PfTRAP) and liver stage specific antigen-1 (PfLSA-1) of Plasmodium falciparum together with GM-CSF protein. A recombinant modified vaccinia virus Ankara (MVA) expressing PfTRAP was injected intramuscularly 6 weeks later to boost the immune response. This sequence of antigen delivery induced a specific and long-lasting T cell and antibody response to PfTRAP as detected by ELISPOT assay and ELISA. Antibody responses were detected after four DNA injections, and were boosted by injection of recombinant MVA expressing PfTRAP. Interferon-gamma secreting antigen-specific T cells were detected in both animals, but only after boosting with recombinant MVA. By screening a panel of PfTRAP-derived peptides, an epitope was identified that was recognized by cytotoxic T lymphocytes in one of the chimpanzees studied. T cells specific for this epitope were present in PBMCs and liver-infiltrating lymphocytes at a frequency of between 1 in 200 and 1 in 500. The high immunogenicity of this prime-boost regimen in chimpanzees supports further assessment of this delivery strategy for the induction of protection against P. falciparum malaria in humans.

Swelling and cyanosis of the tongue associated with use of a laryngeal mask airway

We present a case report of a patient who developed acute swelling of the tongue during anaesthesia using the laryngeal mask airway. The swelling was thought to be due to obstruction of the venous drainage of the tongue. This was associated with isolated cyanosis of the tongue and paraesthesia. The swelling and cyanosis of the tongue resolved rapidly after removal of the laryngeal mask airway. The patient suffered paraesthesia of the tip of the tongue that lasted for two weeks.