Combined islet and kidney xenotransplantation for diabetic nephropathy: an update in ongoing research for a clinically relevant application of porcine islet transplantation

Combined islet and kidney xenotransplantation for the treatment of diabetic nephropathy represents a compelling and increasingly relevant therapeutic possibility for an ever-growing number of patients who would benefit from both durable renal replacement and cure of the underlying cause of their renal insufficiency: diabetes. Here we briefly review immune barriers to islet transplantation, highlight preclinical progress in the field, and summarize our experience with combined islet and kidney xenotransplantation, including both challenges with islet-kidney composite grafts as well as our recent success with sequential kidney followed by islet xenotransplantation in a pig-to-baboon model.

An ex vivo model of interactions between extracellular vesicles and peripheral mononuclear blood cells in whole blood

Extracellular vesicles (EVs) can be loaded with therapeutic cargo and engineered for retention by specific body sites; therefore, they have great potential for targeted delivery of biomolecules to treat diseases. However, the pharmacokinetics and biodistribution of EVs in large animals remain relatively unknown, especially in primates. We recently reported that when cell culture-derived EVs are administered intravenously to Macaca nemestrina (pig-tailed macaques), they differentially associate with specific subsets of peripheral blood mononuclear cells (PBMCs). More than 60% of CD20+ B cells were observed to associate with EVs for up to 1 h post-intravenous administration. To investigate these associations further, we developed an ex vivo model of whole blood collected from healthy pig-tailed macaques. Using this ex vivo system, we found that labelled EVs preferentially associate with B cells in whole blood at levels similar to those detected in vivo. This study demonstrates that ex vivo blood can be used to study EV-blood cell interactions.

Integrated cognitive behavioral intervention for functional tics (I-CBiT): case reports and treatment formulation

Introduction

The onset of the COVID-19 pandemic saw a global surge in functional tic-like behaviors (FTLBs). FTLBs are unique from primary tic disorders. They are thought to manifest through a complex interplay between environmental and personal factors, including the stress-arousal system, and are characterized by their sudden and explosive onset. Accordingly, common interventions for tic disorders show limited efficacy in this population. We present an Integrated Cognitive Behavioral Intervention for Functional Tics (I-CBiT) that uses an urge acceptance model to manage tics and related stress and anxiety.

Methods

We describe the treatment outcomes of eight young people presenting with new and sudden onset FTLBs who underwent I-CBiT, which integrates traditional behavioral tic interventions with third-wave cognitive behavioral therapies. All cases completed the three-phase intervention involving core components of psychoeducation, exposure and response prevention with urge acceptance, sensory grounding strategies, and cognitive behavioral intervention targeting the stress-arousal system. Tic severity and impairment were assessed prior to treatment and at completion.

Results

All cases showed a significant reduction in tic severity post I-CBiT and an improvement in overall daily living function. These cases highlight the role of urge acceptance in managing both tic urges and the underlying stress-arousal system to bring about long-term change.

Conclusion

We demonstrated the efficacy of I-CBiT for managing FTLBs. Our findings illustrate the importance of treating underlying stress and anxiety in this population and, therefore, a need for greater interaction between multidisciplinary services in managing FTLBs to comprehensively cover the varied symptom presentations linked to thoughts, emotions, bodily sensations, and stress responses.

A dimensional investigation of error-related negativity (ERN) and self-reported psychiatric symptoms

Alterations in error processing are implicated in a range of DSM-defined psychiatric disorders. For instance, obsessive-compulsive disorder (OCD) and generalised anxiety disorder show enhanced electrophysiological responses to errors-i.e. error-related negativity (ERN)-while others like schizophrenia have an attenuated ERN. However, as diagnostic categories in psychiatry are heterogeneous and also highly intercorrelated, the precise mapping of ERN enhancements/impairments is unclear. To address this, we recorded electroencephalograms (EEG) from 196 participants who performed the Flanker task and collected scores on 9 questionnaires assessing psychiatric symptoms to test if a dimensional framework could reveal specific transdiagnostic clinical manifestations of error processing dysfunctions. Contrary to our hypothesis, we found non-significant associations between ERN amplitude and symptom severity of OCD, trait anxiety, depression, social anxiety, impulsivity, eating disorders, alcohol addiction, schizotypy and apathy. A transdiagnostic approach did nothing to improve signal; there were non-significant associations between all three transdiagnostic dimensions (anxious-depression, compulsive behaviour and intrusive thought, and social withdrawal) and ERN magnitude. In these same individuals, we replicated a previously published transdiagnostic association between goal-directed learning and compulsive behaviour and intrusive thought. Possible explanations discussed are (i) that associations between the ERN and psychopathology might be smaller than previously assumed, (ii) that these associations might depend on a greater level of symptom severity than other transdiagnostic cognitive biomarkers, or (iii) that task parameters, such as the ratio of compatible to incompatible trials, might be crucial for ensuring the sensitivity of the ERN to clinical phenomena.

Idiopathic Pulmonary Arterial Hypertension Unmasked by Pregnancy

A 31-year old woman presented to the acute medical unit 9 days post-partum with shortness of breath and peripheral oedema. Initially suspected to have either a pulmonary embolism or post-partum cardiomyopathy, she proceeded to have imaging including a CT Pulmonary angiogram and echocardiogram, which were suggestive of pulmonary hypertension and severe right heart failure. Her history and other investigations did not reveal any obvious cause for this. She was transferred to a specialist centre where she was diagnosed with Idiopathic Pulmonary Arterial Hypertension (IPAH), previously known as primary pulmonary hypertension. Shortness of breath during pregnancy and in the postpartum period is a relatively common acute medical presentation. Whilst IPAH is a rare diagnosis, it carries a high mortality rate, particularly in pregnancy, and requires prompt specialist investigation, diagnosis and management.

Proceedings of the First International Conference on Stepped Wedge Trial Design

I1 Introduction

Mona Kanaan, Noreen Dadirai Mdege, Ada Keding

O1 The HiSTORIC trial: a hybrid before-and-after and stepped wedge design

RA Parker, N Mills, A Shah, F Strachan, C Keerie, CJ Weir

O2 Stepped wedge trials with non-uniform correlation structure

Andrew Forbes, Karla Hemming

O3 Challenges and solutions for the operationalisation of the ENHANCE study: a pilot stepped wedge trial within a general practice setting

Sarah A Lawton, Emma Healey, Martyn Lewis, Elaine Nicholls, Clare Jinks, Valerie Tan, Andrew Finney, Christian D Mallen, on behalf of the ENHANCE Study Team

O4 Early lessons from the implementation of a stepped wedge trial design investigating the effectiveness of a training intervention in busy health care settings: the Thistle study

Erik Lenguerrand, Graeme MacLennan, John Norrie, Siladitya Bhattacharya, Tim Draycott, on behalf of the Thistle group

O5 Sample size calculation for longitudinal cluster randomised trials: a unified framework for closed cohort and repeated cross-section designs

Richard Hooper, Steven Teerenstra, Esther de Hoop, Sandra Eldridge

O6 Restricted randomisation schemes for stepped-wedge studies with a cluster-level covariate

Alan Girling, Monica Taljaard

O7 A flexible modelling of the time trend for the analysis of stepped wedge trials: results of a simulation study

Gian Luca Di Tanna, Antonio Gasparrini

P1 Tackling acute kidney injury – a UK stepped wedge clinical trial of hospital-level quality improvement interventions

Anna Casula, Fergus Caskey, Erik Lenguerrand, Shona Methven, Stephanie MacNeill, Margaret May, Nicholas Selby

P2 Sample size considerations for quantifying secondary bacterial transmission in a stepped wedge trial of influenza vaccine

Leon Danon, Hannah Christensen, Adam Finn, Margaret May

P3 Sample size calculation for time-to-event data in stepped wedge cluster randomised trials

Fumihito Takanashi, Ada Keding, Simon Crouch, Mona Kanaan

P4 Sample size calculations for stepped-wedge cluster randomised trials with unequal cluster sizes

Caroline A. Kristunas, Karen L. Smith, Laura J. Gray

P5 The design of stepped wedge trials with unequal cluster sizes

John N.S. Matthews

P6 Promoting Recruitment using Information Management Efficiently (PRIME): a stepped wedge SWAT (study-within-a-trial)

R Al-Shahi Salman, RA Parker, A Maxwell, M Dennis, A Rudd, CJ Weir

P7 Implications of misspecified mixed effect models in stepped wedge trial analysis: how wrong can it be?

Jennifer A Thompson, Katherine L Fielding, Calum Davey, Alexander M Aiken, James R Hargreaves, Richard J Hayes

S1 Stepped Wedge Designs with Multiple Interventions

Vivian H Lyons, Lingyu Li, James Hughes, Ali Rowhani-Rahbar

S2 Analysis of the cross-sectional stepped wedge cluster randomised trial

Karla Hemming, Monica Taljaard, Andrew Forbes

Echocardiographic Characterization of a Murine Model of Hypertrophic Obstructive Cardiomyopathy Induced by Cardiac-specific Overexpression of Epidermal Growth Factor Receptor 2

Although rare, hypertrophic cardiomyopathy (HCM) with midventricular obstruction is often associated with severe symptoms and complications. None of the existing HCM animal models display this particular phenotype. Our group developed a mouse line that overexpresses the ErbB2 receptor (ErbB2(tg)) in cardiomyocytes; we previously showed that the ErbB2 receptor induces cardiomyocyte hypertrophy, myocyte disarray, and fibrosis compatible with HCM. In the current study, we sought to further echocardiographically characterize the ErbB2(tg) mouse line as a model of HCM. Compared with their wild-type littermates, ErbB2(tg) mice show increased left ventricular (LV) mass, concentric LV hypertrophy, and papillary muscle hypertrophy. This hypertrophy was accompanied by diastolic dysfunction, expressed as reduced E:A ratio, prolonged deceleration time, and elevated E:e' ratio. In addition, ErbB2(tg) mice consistently showed midcavity obstruction with elevated LV gradients, and the flow profile revealed a prolonged pressure increase and a delayed peak, indicating dynamic obstruction. The ejection fraction was increased in ErbB2(tg) mice, due to reduced end-diastolic and end-systolic LV volumes. Furthermore, systolic radial strain and systolic radial strain rate but not systolic circumferential strain and longitudinal strain were decreased in ErbB2(tg) compared with wild-type mice. In conclusion, the phenotype of the ErbB2(tg) mouse model is consistent with midventricular HCM in many important aspects, including massive LV hypertrophy, diastolic dysfunction, and midcavity obstruction. This pattern is unique for a small animal model, suggesting that ErbB2(tg) mice may be well suited for research into the hemodynamics and treatment of this rare form of HCM.

Adult zebrafish intestine resection: a novel model of short bowel syndrome, adaptation, and intestinal stem cell regeneration

Loss of significant intestinal length from congenital anomaly or disease may lead to short bowel syndrome (SBS); intestinal failure may be partially offset by a gain in epithelial surface area, termed adaptation. Current in vivo models of SBS are costly and technically challenging. Operative times and survival rates have slowed extension to transgenic models. We created a new reproducible in vivo model of SBS in zebrafish, a tractable vertebrate model, to facilitate investigation of the mechanisms of intestinal adaptation. Proximal intestinal diversion at segment 1 (S1, equivalent to jejunum) was performed in adult male zebrafish. SBS fish emptied distal intestinal contents via stoma as in the human disease. After 2 wk, S1 was dilated compared with controls and villus ridges had increased complexity, contributing to greater villus epithelial perimeter. The number of intervillus pockets, the intestinal stem cell zone of the zebrafish increased and contained a higher number of bromodeoxyuridine (BrdU)-labeled cells after 2 wk of SBS. Egf receptor and a subset of its ligands, also drivers of adaptation, were upregulated in SBS fish. Igf has been reported as a driver of intestinal adaptation in other animal models, and SBS fish exposed to a pharmacological inhibitor of the Igf receptor failed to demonstrate signs of intestinal adaptation, such as increased inner epithelial perimeter and BrdU incorporation. We describe a technically feasible model of human SBS in the zebrafish, a faster and less expensive tool to investigate intestinal stem cell plasticity as well as the mechanisms that drive intestinal adaptation.

The clinical effectiveness and cost-effectiveness of different surveillance mammography regimens after the treatment for primary breast cancer: systematic reviews registry database analyses and economic evaluation

BACKGROUND

Following primary breast cancer treatment, the early detection of ipsilateral breast tumour recurrence (IBTR) or ipsilateral secondary cancer in the treated breast and detection of new primary cancers in the contralateral breast is beneficial for survival. Surveillance mammography is used to detect these cancers, but the optimal frequency of surveillance and the length of follow-up are unclear.

OBJECTIVES

To identify feasible management strategies for surveillance and follow-up of women after treatment for primary breast cancer in a UK setting, and to determine the effectiveness and cost-effectiveness of differing regimens.

METHODS

A survey of UK breast surgeons and radiologists to identify current surveillance mammography regimens and inform feasible alternatives; two discrete systematic reviews of evidence published from 1990 to mid 2009 to determine (i) the clinical effectiveness and cost-effectiveness of differing surveillance mammography regimens for patient health outcomes and (ii) the test performance of surveillance mammography in the detection of IBTR and metachronous contralateral breast cancer (MCBC); statistical analysis of individual patient data (West Midlands Cancer Intelligence Unit Breast Cancer Registry and Edinburgh data sets); and economic modelling using the systematic reviews results, existing data sets, and focused searches for specific data analysis to determine the effectiveness and cost-utility of differing surveillance regimens.

RESULTS

The majority of survey respondents initiate surveillance mammography 12 months after breast-conserving surgery (BCS) (87%) or mastectomy (79%). Annual surveillance mammography was most commonly reported for women after BCS or after mastectomy (72% and 53%, respectively). Most (74%) discharge women from surveillance mammography, most frequently 10 years after surgery. The majority (82%) discharge from clinical follow-up, most frequently at 5 years. Combining initiation, frequency and duration of surveillance mammography resulted in 54 differing surveillance regimens for women after BCS and 56 for women following mastectomy. The eight studies included in the clinical effectiveness systematic review suggest surveillance mammography offers a survival benefit compared with a surveillance regimen that does not include surveillance mammography. Nine studies were included in the test performance systematic review. For routine IBTR detection, surveillance mammography sensitivity ranged from 64% to 67% and specificity ranged from 85% to 97%. For magnetic resonance imaging (MRI), sensitivity ranged from 86% to 100% and specificity was 93%. For non-routine IBTR detection, sensitivity and specificity for surveillance mammography ranged from 50% to 83% and from 57% to 75%, respectively, and for MRI from 93% to 100% and from 88% to 96%, respectively. For routine MCBC detection, one study reported sensitivity of 67% and specificity of 50% for both surveillance mammography and MRI, although this was a highly select population. Data set analysis showed that IBTR has an adverse effect on survival. Furthermore, women experiencing a second tumour measuring >20 mm in diameter were at a significantly greater risk of death than those with no recurrence or those whose tumour was <10 mm in diameter. In the base-case analysis, the strategy with the highest net benefit, and most likely to be considered cost-effective, was surveillance mammography alone, provided every 12 months at a societal willingness to pay for a quality-adjusted life-year of either £20,000 or £30,000. The incremental cost-effectiveness ratio for surveillance mammography alone every 12 months compared with no surveillance was £4727.

LIMITATIONS

Few studies met the review inclusion criteria and none of the studies was a randomised controlled trial. The limited and variable nature of the data available precluded any quantitative analysis. There was no useable evidence contained in the Breast Cancer Registry database to assess the effectiveness of surveillance mammography directly. The results of the economic model should be considered exploratory and interpreted with caution given the paucity of data available to inform the economic model.

CONCLUSIONS

Surveillance is likely to improve survival and patients should gain maximum benefit through optimal use of resources, with those women with a greater likelihood of developing IBTR or MCBC being offered more comprehensive and more frequent surveillance. Further evidence is required to make a robust and informed judgement on the effectiveness of surveillance mammography and follow-up. The utility of national data sets could be improved and there is a need for high-quality, direct head-to-head studies comparing the diagnostic accuracy of tests used in the surveillance population.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Lesion size is a major determinant of the mammographic features of ductal carcinoma in situ: findings from the Sloane project

AIM

To assess the radiological features of calcific ductal carcinoma in situ (DCIS) in a large, multicentre dataset according to grade and size, and to investigate the possibility that DCIS has different mammographic features when small.

MATERIALS AND METHODS

The dataset consisted of all Sloane Project DCIS cases where calcification was present mammographically and histological grade and size were available. The radiology data form classifies calcific DCIS as casting/linear, granular/irregular, or punctate. The pathology dataset includes cytonuclear grade and microscopic tumour size. Correlations were sought between the radiological findings and DCIS grade and size. The significance of differences was assessed using the chi-square test and chi-square test for trend.

RESULTS

One thousand, seven hundred and eighty-three cases were included in the study. Of these, 1128, 485, and 170 had high, intermediate, and low-grade DCIS, respectively. Casting calcification was more frequently seen the higher the grade of DCIS, occurring in 58% of high grade, 38% of intermediate grade, and 26% of low-grade cases, respectively (p<0.001). Casting calcification was also increasingly common with increasing lesion size, irrespective of the histological grade (p<0.001). Thus casting calcifications in small (<10mm) high-grade DCIS lesions were seen with a similar frequency (50%) to those in moderate-sized (21-30 mm) intermediate-grade lesions (48%), and to those in large (>30 mm) low-grade lesions (46%).

CONCLUSION

Lesion size has a strong influence on the radiological features of calcific DCIS; small, high-grade lesions often show no casting calcifications, whereas casting calcifications are seen in nearly half of large, low-grade lesions. As small clusters of punctate or granular calcifications may represent high-grade DCIS, an aggressive clinical approach to the diagnosis of such lesions is recommended as the adequate treatment of high-grade DCIS will prevent the occurrence of potentially life-threatening high-grade invasive disease.

EULID project: European living donation and public health

The choice of transplantation from a living donor offers advantages over a deceased donor. However, it also carries disadvantages related to donor risks in terms of health and safety. Furthermore, there are several controversial ethical aspects to be taken into account. Several national and international institutions and the scientific community have stated standards that have great influence on professional codes and legislations. Living organ donation and transplantation are to some extent regulated by parliamentary acts in most European countries. It is necessary to take a step forward to develop a legal framework to regulate all of these processes to guarantee the quality and to prevent illegal and nonethical practices. It is also necessary to develop and implement living donor protection practices not only in terms of physical health, but also to minimize potential impacts on the psychological, social, and economic spheres. Finally, an additional effort should be made to create a database model with recommendations for registration practices as part of the standardized follow-up care for the living donor. The European Living Donation (EULID) project's (http://www.eulivingdonor.eu/) main objective was to contribute to a European consensus to set standards and recommendations about legal, ethical, and living donor protection practices to guarantee the health and safety of living donors.

Mammographic bi-dimensional product: a powerful predictor of successful excision of ductal carcinoma in situ

BACKGROUND

The aim of this analysis was to ascertain whether uni-dimensional measurement of mammographic microcalcification, the product of bi-dimensional measurement, calcification morphology, and pathological grade are helpful in predicting successful single therapeutic wide local excision (WLE) of ductal carcinoma in situ (DCIS).

METHODS

The study group comprised 505 patients whose mammograms showed the DCIS as calcification, and in whom a non-operative diagnosis had been obtained and WLE attempted. The extents of mammographic calcifications was measured in two planes at 90 degrees on the oblique view, the appearances classified as comedo, granular, or punctate. DCIS was graded using cyto-nuclear characteristics.

RESULTS

Three hundred and forty-two patients had a successful first WLE and 163 patients had further surgery. A uni-dimensional measurement of <35 mm and a bi-dimensional product of <800 mm(2) were associated with successful excision (69 versus 54%, p=0.02 and 70 versus 27%, p=0.0001, respectively). Mammographic calcification morphology and histological grade did not influence the likelihood of a successful first WLE. For high-grade DCIS, the upper limit of the bi-dimensional product associated with successful WLE was 800 mm(2) (69 versus 24%, p=0.0003). In contrast, for non-high-grade DCIS, the cut-off was 400 mm(2) (73 versus 33%, p=0.01). Analyses based on mammographic calcification morphology gave similar findings.

CONCLUSION

The mammographic bi-dimensional product is a powerful predictor of successful WLE of DCIS when combined with histological grade and/or calcification morphology.

Wound-healing activity of Morinda citrifolia fruit juice on diabetes-induced rats

OBJECTIVE

Morinda citrifolia L. is a traditional Polynesian medicinal plant which is apparently useful for bowel disorders, skin inflammation, infection, mouth ulcers and wound healing. This study aimed to evaluate the wound-healing activity of Morinda citrifolia fruit juice in streptozotocin-induced diabetic rats.

METHOD

An excision wound model was used. The animals were weight-matched and placed into three groups (n = 6 per group). Group 1 animals served as normal controls, while animals in groups 2 and 3 served as diabetic controls and experimental diabetic animals respectively. All animals were anaesthetised and a full-thickness excision wound (circular area of 300 mm2 and 2 mm deep) was created. Group 3 animals were given the juice of Morinda citrifolia fruit (100 ml per kilogram of body weight) in their drinking water for 10 days. Wound area measurements were taken on days 1, 5 and 11. Blood samples were collected simultaneously for glucose measurement. Granulation tissue that had formed on the wound was excised on day 11 and processed for histological and biochemical analysis.

RESULTS

The wound area of the Morinda citrifolia-treated group reduced by 73% (p < 0.001) when compared with the diabetic controls (63%). Significant increases in the weight of granulation tissue (p < 0.001) and hydroxyproline content (p < 0.00 1, 92.16 +/- 4.02) were observed. The protein content was moderately high. Histological studies showed that collagen was laid down faster in the experimental diabetic animals than in the normal control and diabetic control groups. Fasting blood glucose values in the diabetic experimental group had reduced by 29% (p < 0.00 1) compared with the diabetic control animals. There was a good correlation between the wound contraction rate and blood glucose values.

CONCLUSION

This study demonstrates that the juice of Morinda citrifolia fruit significantly reduces blood sugar levels and hastens wound healing in diabetic rats.

Coupling ATP hydrolysis to DNA strand passage in type IIA DNA topoisomerases

Type IIA topos (topoisomerases) catalyse topological conversions of DNA through the passage of one double strand through a transient break in another. In the case of the archetypal enzyme, DNA gyrase, it has always been apparent that the enzyme couples the free energy of ATP hydrolysis to the introduction of negative supercoiling, and the structural details of this process are now becoming clearer. The homologous type IIA enzymes such as topo IV and eukaryotic topo II also require ATP and it has more recently been shown that the energy of hydrolysis is coupled to a reduction of supercoiling or catenation (linking) beyond equilibrium. The mechanism behind this effect is less clear. We review the energy coupling process in both classes of enzyme and describe recent mechanistic and structural work on gyrase that addresses the mechanism of energy coupling.

The Effects of Metal Ions on the Structure and Stability of the DNA Gyrase B Protein

The effects of mono- and divalent metal ions on the DNA gyrase B subunit, on its 43 kDa and 47 kDa domains, and on two mutants in the Toprim domain (D498A and D500C) were investigated by means of circular dichroism and protein melting experiments. Both types of metal ion, with the notable exception of Mn2+, did not affect the conformational properties of the enzyme subunit at room temperature, but were able to produce selective and differential effects on protein stability. In particular, monovalent (K+) ions increased the stability of the gyrase B structure, whereas destabilising effects were most prominent using Mn2+ as the metal ion. Ca2+ and Mg2+ produced comparable changes in the gyrase B melting profile. Additionally, we found that monovalent (K+) ions were more effective in the 43 kDa N-terminal domain where ATP binding occurs, whereas divalent ions caused large modifications in the conformational stability of the 47 kDa C-terminal domain. Our results on gyrase B mutants indicate that D498 interacts with Mn2+, whereas it has little effect on the binding of the other ions tested. A D500C mutation, in contrast, effectively impairs Mg2+ affinity, suggesting effective contacts between this ion and D500 in the wild-type enzyme. Hence, the sites of metal ion complexation within the Toprim domain are modulated by the nature of the ion species. These results suggest a double role played by metal ions in the catalytic steps involving DNA gyrase B. One has to do with direct involvement of cations complexed to the Toprim domain in the DNA cutting-rejoining process, the other, until now overlooked, is connected to the dramatic changes in protein flexibility produced by ion binding, which reduces the energy required for the huge conformational changes essential for the catalytic cycle to occur.