Randomized controlled trials comparing gastric bypass, gastric band, and sleeve gastrectomy: A systematic review examining validity and applicability to wider clinical practice.

Consideration of how applicable the results of surgical trials are to clinical practice is important to inform decision-making. Randomized controlled trials comparing at least two surgical interventions (of gastric bypass, gastric band, and sleeve gastrectomy) for severe and complex obesity were examined using the PRagmatic Explanatory Continuum Indicator Summary-2 tool, to consider how applicable the trial results are to clinical practice, and the Risk of Bias 2 tool, to examine validity. MEDLINE, Embase, and CENTRAL databases were searched for studies published between November 2013 and June 2021, and 15 were identified. Using the PRagmatic Explanatory Continuum Indicator Summary-2 tool, three were classified as pragmatic, with good applicability to clinical practice. Ten had more explanatory domains but did include some pragmatic characteristics, and two were predominantly explanatory. This was due to some trial design features that would not be considered applicable to the wider clinical setting, including being single-centered, having prescribed intervention delivery methods, and intensive follow-up regimens. Only two trials had low risk of bias, of which one was considered pragmatic. Three had high risk of bias. Overall, few trials in bariatric surgery are pragmatic with low risk of bias. Well-designed pragmatic trials are needed to inform practice and reduce research waste.

Development and pilot testing of a patient-reported outcome measure to assess symptoms of parastomal hernia.

AIM: The aim was to develop and pilot a patient-reported outcome measure (PROM) to assess symptoms of parastomal hernia (PSH). METHODS: Standard questionnaire development was undertaken (phases 1-3). An initial list of questionnaire domains was identified from validated colorectal cancer PROMs and from semi-structured interviews with patients with a PSH and health professionals (phase 1). Domains were operationalized into items in a provisional questionnaire, and 'think-aloud' patient interviews explored face validity and acceptability (phase 2). The updated questionnaire was piloted in patients with a stoma who had undergone colorectal surgery and had a computed tomography scan available for review. Patient-reported symptoms were examined in relation to PSH (phase 3). Three sources determined PSH presence: (i) data about PSH presence recorded in hospital notes, (ii) independent expert review of the computed tomography scan and (iii) patient report of being informed of a PSH by a health professional. RESULTS: For phase 1, 169 and 127 domains were identified from 70 PROMs and 29 interviews respectively. In phase 2, 14 domains specific to PSH were identified and operationalized into questionnaire items. Think-aloud interviews led to three minor modifications. In phase 3, 44 completed questionnaires were obtained. Missing data were few: 5/660 items. PSH symptom scores associated with PSH presence varied between different data sources. The scale with the most consistent differences between PSH presence and absence and all data sources was the stoma appearance scale. CONCLUSION: A PROM to examine the symptoms of PSH has been developed from the literature and views of key informants. Although preliminary testing shows it to be understandable and acceptable it is uncertain if it is sensitive to PSH-specific symptoms and further psychometric testing is needed.

How do pilot and feasibility studies inform randomised placebo-controlled trials in surgery? A systematic review.

INTRODUCTION: Randomised controlled trials (RCTs) with a placebo comparator are considered the gold standard study design when evaluating healthcare interventions. These are challenging to design and deliver in surgery. Guidance recommends pilot and feasibility work to optimise main trial design and conduct; however, the extent to which this occurs in surgery is unknown. METHOD: A systematic review identified randomised placebo-controlled surgical trials. Articles published from database inception to 31 December 2020 were retrieved from Ovid-MEDLINE, Ovid-EMBASE and CENTRAL electronic databases, hand-searching and expert knowledge. Pilot/feasibility work conducted prior to the RCTs was then identified from examining citations and reference lists. Where studies explicitly stated their intent to inform the design and/or conduct of the future main placebo-controlled surgical trial, they were included. Publication type, clinical area, treatment intervention, number of centres, sample size, comparators, aims and text about the invasive placebo intervention were extracted. RESULTS: From 131 placebo surgical RCTs included in the systematic review, 47 potentially eligible pilot/feasibility studies were identified. Of these, four were included as true pilot/feasibility work. Three were original articles, one a conference abstract; three were conducted in orthopaedic surgery and one in oral and maxillofacial surgery. All four included pilot RCTs, with an invasive surgical placebo intervention, randomising 9-49 participants in 1 or 2 centres. They explored the acceptability of recruitment and the invasive placebo intervention to patients and trial personnel, and whether blinding was possible. One study examined the characteristics of the proposed invasive placebo intervention using in-depth interviews. CONCLUSION: Published studies reporting feasibility/pilot work undertaken to inform main placebo surgical trials are scarce. In view of the difficulties of undertaking placebo surgical trials, it is recommended that pilot/feasibility studies are conducted, and more are reported to share key findings and optimise the design of main RCTs. PROSPERO REGISTRATION NUMBER: CRD42021287371.

Development of a Bariatric Surgery Core Data Set for an International Registry.

PURPOSE: Bariatric and metabolic surgery is an effective treatment for severe and complex obesity; however, robust long-term data comparing operations is lacking. Clinical registries complement clinical trials in contributing to this evidence base. Agreement on standard data for bariatric registries is needed to facilitate comparisons. This study developed a Core Registry Set (CRS) - core data to include in bariatric surgery registries globally. MATERIALS AND METHODS: Relevant items were identified from a bariatric surgery research core outcome set, a registry data dictionary project, systematic literature searches, and a patient advisory group. This comprehensive list informed a questionnaire for a two-round Delphi survey with international health professionals. Participants rated each item's importance and received anonymized feedback in round 2. Using pre-defined criteria, items were then categorized for voting at a consensus meeting to agree the CRS. RESULTS: Items identified from all sources were grouped into 97 questionnaire items. Professionals (n = 272) from 56 countries participated in the round 1 survey of which 45% responded to round 2. Twenty-four professionals from 13 countries participated in the consensus meeting. Twelve items were voted into the CRS including demographic and bariatric procedure information, effectiveness, and safety outcomes. CONCLUSION: This CRS is the first step towards unifying bariatric surgery registries internationally. We recommend the CRS is included as a minimum dataset in all bariatric registries worldwide. Adoption of the CRS will enable meaningful international comparisons of bariatric operations. Future work will agree definitions and measures for the CRS including incorporating quality-of-life measures defined in a parallel project.

Impact on Health-Related Quality of Life of Video-Assisted Thoracoscopic Surgery for Lung Cancer.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) approaches are increasingly used in lung cancer surgery, but little is known about their impact on patients' health-related quality of life (HRQL). This prospective study measured recovery and HRQL in the year after VATS for non-small cell lung cancer (NSCLC) and explored the feasibility of HRQL data collection in patients undergoing VATS or open lung resection. PATIENTS AND METHODS: Consecutive patients referred for surgical assessment (VATS or open surgery) for proven/suspected NSCLC completed HRQL and fatigue assessments before and 1, 3, 6 and 12 months post-surgery. Mean HRQL scores were calculated for patients who underwent VATS (segmental, wedge or lobectomy resection). Paired t-tests compared mean HRQL between baseline and expected worst (1 month), early (3 months) and longer-term (12 months) recovery time points. RESULTS: A total of 92 patients received VATS, and 18 open surgery. Questionnaire response rates were high (pre-surgery 96-100%; follow-up 67-85%). Pre-surgery, VATS patients reported mostly high (good) functional health scores [(European Organisation for Research and Treatment of Cancer) EORTC function scores > 80] and low (mild) symptom scores (EORTC symptom scores < 20). One-month post-surgery, patients reported clinically and statistically significant deterioration in overall health and physical, role and social function (19-36 points), and increased fatigue, pain, dyspnoea, appetite loss and constipation [EORTC 12-26; multidimensional fatigue inventory (MFI-20) 3-5]. HRQL had not fully recovered 12 months post-surgery, with reduced physical, role and social function (10-14) and persistent fatigue and dyspnoea (EORTC 12-22; MFI-20 2.7-3.2). CONCLUSIONS: Lung resection has a considerable detrimental impact on patients' HRQL that is not fully resolved 12 months post-surgery, despite a VATS approach.

Reporting of key methodological issues in placebo-controlled trials of surgery needs improvement: a systematic review.

OBJECTIVES: To examine key methodological considerations for using a placebo intervention in randomized controlled trials (RCTs) evaluating invasive procedures, including surgery. STUDY DESIGN AND SETTING: RCTs comparing an invasive procedure with a placebo were included in this systematic review. Articles published from database inception to December 31, 2017, were retrieved from Ovid MEDLINE, Ovid EMBASE and CENTRAL electronic databases, by handsearching references and expert knowledge. Data on trial characteristics (clinical area, nature of invasive procedure, number of patients and centers) and key methodological (rationale for using placebos, minimization of risk, information provision, offering the treatment intervention to patients randomized to placebo, delivery of cointerventions, and intervention standardization and fidelity) were extracted and summarized descriptively. RESULTS: One hundred thirteen articles reporting 96 RCTs were identified. Most were conducted in gastrointestinal surgery (n = 40, 42%) and evaluated minimally invasive procedures (n = 44, 46%). Over two-thirds randomized fewer than 100 patients (n = 65, 68%) and a third were single center (n = 31, 32%). A third (n = 33, 34%) did not report a rationale for using a placebo. Most common strategies to minimize patient risk were operator skill (n = 22, 23%) and independent data monitoring (n = 28, 29%). Provision of patient information regarding placebo use was infrequently reported (n = 11, 11%). Treatment interventions were offered to patients randomized to placebo in 43 trials (45%). Cointerventions were inconsistently reported, but 64 trials (67%) stated that anesthesia was matched between groups. Attempts to standardize interventions and monitor their delivery were reported in n = 7, (7%) and n = 4, (4%) trials, respectively. CONCLUSION: Most placebo-controlled trials in surgery evaluate minor surgical procedures and currently there is inconsistent reporting of key trial methods. There is a need for guidance to optimize the transparency of trial reporting in this area.

Laparoscopically assisted versus open oesophagectomy for patients with oesophageal cancer-the Randomised Oesophagectomy: Minimally Invasive or Open (ROMIO) study: protocol for a randomised controlled trial (RCT).

INTRODUCTION: Surgery (oesophagectomy), with neoadjuvant chemo(radio)therapy, is the main curative treatment for patients with oesophageal cancer. Several surgical approaches can be used to remove an oesophageal tumour. The Ivor Lewis (two-phase procedure) is usually used in the UK. This can be performed as an open oesophagectomy (OO), a laparoscopically assisted oesophagectomy (LAO) or a totally minimally invasive oesophagectomy (TMIO). All three are performed in the National Health Service, with LAO and OO the most common. However, there is limited evidence about which surgical approach is best for patients in terms of survival and postoperative health-related quality of life. METHODS AND ANALYSIS: We will undertake a UK multicentre randomised controlled trial to compare LAO with OO in adult patients with oesophageal cancer. The primary outcome is patient-reported physical function at 3 and 6 weeks postoperatively and 3 months after randomisation. Secondary outcomes include: postoperative complications, survival, disease recurrence, other measures of quality of life, spirometry, success of patient blinding and quality assurance measures. A cost-effectiveness analysis will be performed comparing LAO with OO. We will embed a randomised substudy to evaluate the safety and evolution of the TMIO procedure and a qualitative recruitment intervention to optimise patient recruitment. We will analyse the primary outcome using a multi-level regression model. Patients will be monitored for up to 3 years after their surgery. ETHICS AND DISSEMINATION: This study received ethical approval from the South-West Franchay Research Ethics Committee. We will submit the results for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ISRCTN10386621.

Impact of question order on prioritisation of outcomes in the development of a core outcome set: a randomised controlled trial.

BACKGROUND: Core outcome set (COS) developers increasingly employ Delphi surveys to elicit stakeholders' opinions of which outcomes to measure and report in trials of a particular condition or intervention. Research outside of Delphi surveys and COS development demonstrates that question order can affect response rates and lead to 'context effects', where prior questions determine an item's meaning and influence responses. This study examined the impact of question order within a Delphi survey for a COS for oesophageal cancer surgery. METHODS: A randomised controlled trial was nested within the Delphi survey. Patients and health professionals were randomised to receive a survey including clinical and patient-reported outcomes (PROs), where the PRO section appeared first or last. Participants rated (1-9) the importance of 68 items for inclusion in a COS (ratings 7-9 considered 'essential'). Analyses considered the impact of question order on: (1) survey response rates; (2) participants' responses; and (3) items retained at end of the survey. RESULTS: In total, 116 patients and 71 professionals returned completed surveys. Question order did not affect response rates among patients, but fewer professionals responded when clinical items appeared first (difference = 31.3%, 95% confidence interval [CI] = 13.6-48.9%, P = 0.001). Question order led to different context effects within patients and professionals. While patients rated clinical items highly, irrespective of question order, more PROs were rated essential when appearing last rather than first (difference = 23.7%, 95% CI = 10.5-40.8%). Among professionals, the greatest impact was on clinical items; a higher percentage rated essential when appearing last (difference = 11.6%, 95% CI = 0.0-23.3%). An interaction between question order and the percentage of PRO/clinical items rated essential was observed for patients (P = 0.025) but not professionals (P = 0.357). Items retained for further consideration at the end of the survey were dependent on question order, with discordant items (retained by one question order group only) observed in patients (18/68 [26%]) and professionals (20/68 [29%]). CONCLUSIONS: In the development of a COS, participants' ratings of potential outcomes within a Delphi survey depend on the context (order) in which the outcomes are asked, consequently impacting on the final COS. Initial piloting is recommended with consideration of the randomisation of items in the survey to reduce potential bias. TRIAL REGISTRATION: The randomised controlled trial reported within this paper was nested within the development of a core outcome set to investigate processes in core outcome set development. Outcomes were not health-related and trial registration was not therefore applicable.

Development of a Core Outcome Set for Clinical Effectiveness Trials in Esophageal Cancer Resection Surgery.

OBJECTIVE: Development of a core outcome set (COS) for clinical effectiveness trials in esophageal cancer resection surgery. BACKGROUND: Inconsistency and heterogeneity in outcome reporting after esophageal cancer resection surgery hampers comparison of trial results and undermines evidence synthesis. COSs provide an evidence-based approach to these challenges. METHODS: A long list of clinical and patient-reported outcomes was identified and categorized into outcome domains. Domains were operationalized into a questionnaire and patients and health professionals rated the importance of items from 1 (not important) to 9 (extremely important) in 2 Delphi survey rounds. Retained items were discussed at a consensus meeting and a final COS proposed. Professionals were surveyed to request endorsement of the COS. RESULTS: A total of 68 outcome domains were identified and operationalized into a questionnaire; 116 (91%) of consenting patients and 72 (77%) of health professionals completed round 1. Round 2 response rates remained high (87% patients, 93% professionals). Rounds 1 and 2 prioritized 43 and 19 items, respectively. Retained items were discussed at a patient consensus meeting and a final 10-item COS proposed, endorsed by 61/67 (91%) professionals and including: overall survival; in-hospital mortality; inoperability; need for another operation; respiratory complications; conduit necrosis and anastomotic leak; severe nutritional problems; ability to eat/drink; problems with acid indigestion or heartburn; and overall quality of life. CONCLUSIONS: The COS is recommended for all pragmatic clinical effectiveness trials in esophageal cancer resection surgery. Further work is needed to delineate the definitions and parameters and explore best methods for measuring the individual outcomes.

A Core Outcome Set for the Benefits and Adverse Events of Bariatric and Metabolic Surgery: The BARIACT Project.

BACKGROUND: Bariatric and metabolic surgery is used as a treatment for patients with severe and complex obesity. However, there is a need to improve outcome selection and reporting in bariatric surgery trials. A Core Outcome Set (COS), an agreed minimum set of outcomes reported in all studies of a specific condition, may achieve this. Here, we present the development of a COS for BARIAtric and metabolic surgery Clinical Trials-the BARIACT Study. METHODS AND FINDINGS: Outcomes identified from systematic reviews and patient interviews informed a questionnaire survey. Patients and health professionals were surveyed three times and asked to rate the importance of each item on a 1-9 scale. Delphi methods provided anonymised feedback to participants. Items not meeting predefined criteria were discarded between rounds. Remaining items were discussed at consensus meetings, held separately with patients and professionals, where the COS was agreed. Data sources identified 2,990 outcomes, which were used to develop a 130-item questionnaire. Round 1 response rates were moderate but subsequently improved to above 75% for other rounds. After rounds 2 and 3, 81 and 14 items were discarded, respectively, leaving 35 items for discussion at consensus meetings. The final COS included nine items: "weight," "diabetes status," "cardiovascular risk," "overall quality of life (QOL)," "mortality," "technical complications of the specific operation," "any re-operation/re-intervention," "dysphagia/regurgitation," and "micronutrient status." The main limitation of this study was that it was based in the United Kingdom only. CONCLUSIONS: The COS is recommended to be used as a minimum in all trials of bariatric and metabolic surgery. Adoption of the COS will improve data synthesis and the value of research data. Future work will establish methods for the measurement of the outcomes in the COS.

A Comparison of Health Professionals' and Patients' Views of the Importance of Outcomes of Bariatric Surgery.

BACKGROUND: A comprehensive evaluation of bariatric surgery is required to inform decision-making. This will include measures of benefit and risk. It is possible that stakeholders involved with surgery value these outcomes differently, although this has not previously been explored. This study aimed to investigate and compare how professionals and patients prioritise outcomes of bariatric surgery. METHODS: Systematic reviews and qualitative interviews created an exhaustive list of outcomes. This informed the development of a 130-item questionnaire, structured in four sections (complications of surgery; clinical effectiveness; signs, symptoms, and other measures; quality of life). Health professionals and patients rated the importance of each item on a 1-9 scale. Items rated 8-9 by at least 70 % of the participants were considered prioritised. Items prioritised in each section were compared between professionals and patients and interrater agreement assessed using kappa statistics (ĸ). RESULTS: One hundred sixty-eight out of four hundred fifty-nine professionals (36.6 %) and 90/465 patients (19.4 %) completed the questionnaire. Professionals and patients prioritised 18 and 25 items, respectively, with 10 overlapping items and 23 discordant items (ĸ 0.363). Examples of items prioritised by both included 'diabetes' and 'leakage from bowel joins'. Examples of discordant items included 're-admission rates' (professionals only) and 'excess skin' (patients only). Poor agreement was seen in the 'quality of life' section (0 overlapping items, 8 discordant, ĸ -0.036). CONCLUSIONS: Although there was some overlap of outcomes prioritised by professionals and patients, there were important differences. We recommend that the views of all relevant health professionals and patients are considered when deciding on outcomes to evaluate bariatric surgery.

What are important outcomes of bariatric surgery? An in-depth analysis to inform the development of a core outcome set and a comparison between the views of surgeons and other health professionals (the BARIACT study).

BACKGROUND: Outcome reporting in bariatric surgery needs uniformity. A core outcome set is an agreed minimum set of outcomes reported in all studies of a particular condition, but members of the bariatric multidisciplinary team might value outcomes differently. The aim of this study was to summarise existing outcome reporting in bariatric surgery, to inform the development of a core outcome set, and to compare outcomes selected as important by type of health professional. METHODS: Outcomes reported in randomised controlled trials (RCTs) and large non-randomised studies, identified by a systematic review, were listed verbatim. Frequency of outcome reporting and uniformity of definition were assessed. A questionnaire to rate the importance of each outcome was completed by members of the bariatric multidisciplinary team. Responses to each item were scored as 1 (not essential) to 9 (absolutely essential). We ranked outcomes according to percentage deemed important (7-9) and according to respondents by type of health professional. FINDINGS: We identified 1088 individual outcomes from 90 studies (39 RCTs), grouped them into health domains, and presented them as a questionnaire with 131 items to 489 multidisciplinary team members. Most outcomes (n=920, 85%) were reported only once. The largest outcome domain was surgical complications, and 432 outcomes (42%) corresponded to an adverse event. Only a quarter of outcomes (n=461) were defined, and were often contradictory. For questionnaire responders (n=164, response rate 33·5%), most were surgeons (n=80, 48·8%), followed by dietitians (n=31, 18·9%), nurses (n=24, 14·6%), physicians (n=12, 7·3%), and others (n=16, 9·9%). Improvement in diabetes was the top outcome for all health professionals. Seven of the surgeon's top ten outcomes were adverse events, compared with three for other health professionals. Groups valued a measure of weight differently (third vs 15th for other health professionals and surgeons, respectively). INTERPRETATION: This study shows that the assessment of bariatric surgery focuses largely on adverse events and resolution of comorbidity, but that reporting is inconsistent and ill-defined. Substantial variation between the views of surgeons and those of other health professionals was evident. The next step is to provide feedback to participants and to survey their views again before a final consensus meeting to produce a core outcome set for the Benefits and Adverse events in BARIAtric surgery Clinical Trials (BARIACT) as a solution to this problem. FUNDING: National Institute for Health Research (NIHR), and the NIHR Health Technology Assessment programme. This work was also undertaken with the support of the MRC ConDuCT-II Hub (Collaboration and innovation for Difficult and Complex randomised controlled Trials In Invasive procedures, MR/K025643/1).

Regional Increase in the Expression of the BCAT Proteins in Alzheimer's Disease Brain: Implications in Glutamate Toxicity.

BACKGROUND: The human branched chain aminotransferases (hBCATm, mitochondrial and hBCATc, cytosolic) are major contributors to brain glutamate production. This excitatory neurotransmitter is thought to contribute to neurotoxicity in neurodegenerative conditions such as Alzheimer's disease (AD) but the expression of hBCAT in this disease has not previously been investigated. OBJECTIVE: The objective of investigating hBCAT expression is to gain insight into potential metabolic pathways that may be dysregulated in AD brain, which would contribute to glutamate toxicity. METHODS: Western blot analysis and immunohistochemistry were used to determine the expression and localization of hBCAT in postmortem frontal and temporal cortex from AD and matched control brains. RESULTS: Western blot analysis demonstrated a significant regional increase in hBCATc expression in the hippocampus (↑ 36%; p-values of 0.012), with an increase of ↑ 160% reported for hBCATm in the frontal and temporal cortex (p-values = 4.22 × 10⁻4 and 2.79 × 10⁻5, respectively) in AD relative to matched controls, with evidence of post-translational modifications to hBCATm, more prominent in AD samples. Using immunohistochemistry, a significant increase in immunopositive labelling of hBCATc was observed in the CA1 and CA4 region of the hippocampus (p-values = 0.011 and 0.026, respectively) correlating with western blot analysis. Moreover, the level of hBCATm in the frontal and temporal cortex correlated significantly with disease severity, as indicated by Braak staging (p-values = 5.63 × 10⁻6 and 9.29 × 10⁻5, respectively). CONCLUSION: The expression of the hBCAT proteins is significantly elevated in AD brain. This may modulate glutamate production and toxicity, and thereby play a role in the pathogenesis of the disease.

Erratum: Development, appraisal, validation and implementation of a consensus protocol for the assessment of cerebral amyloid angiopathy in post-mortem brain tissue.

In a collaboration involving 11 groups with research interests in cerebral amyloid angiopathy (CAA), we used a two-stage process to develop and in turn validate a new consensus protocol and scoring scheme for the assessment of CAA and associated vasculopathic abnormalities in post-mortem brain tissue. Stage one used an iterative Delphi-style survey to develop the consensus protocol. The resultant scoring scheme was tested on a series of digital images and paraffin sections that were circulated blind to a number of scorers. The scoring scheme and choice of staining methods were refined by open-forum discussion. The agreed protocol scored parenchymal and meningeal CAA on a 0-3 scale, capillary CAA as present/absent and vasculopathy on 0-2 scale, in the 4 cortical lobes that were scored separately. A further assessment involving three centres was then undertaken. Neuropathologists in three centres (Bristol, Oxford and Sheffield) independently scored sections from 75 cases (25 from each centre) and high inter-rater reliability was demonstrated. Stage two used the results of the three-centre assessment to validate the protocol by investigating previously described associations between APOE genotype (previously determined), and both CAA and vasculopathy. Association of capillary CAA with or without arteriolar CAA with APOE ε4 was confirmed. However APOE ε2 was also found to be a strong risk factor for the development of CAA, not only in AD but also in elderly non-demented controls. Further validation of this protocol and scoring scheme is encouraged, to aid its wider adoption to facilitate collaborative and replication studies of CAA.[This corrects the article on p. 19 in vol. 3, PMID: 24754000.].

Development, appraisal, validation and implementation of a consensus protocol for the assessment of cerebral amyloid angiopathy in post-mortem brain tissue.

In a collaboration involving 11 groups with research interests in cerebral amyloid angiopathy (CAA), we used a two-stage process to develop and in turn validate a new consensus protocol and scoring scheme for the assessment of CAA and associated vasculopathic abnormalities in post-mortem brain tissue. Stage one used an iterative Delphi-style survey to develop the consensus protocol. The resultant scoring scheme was tested on a series of digital images and paraffin sections that were circulated blind to a number of scorers. The scoring scheme and choice of staining methods were refined by open-forum discussion. The agreed protocol scored parenchymal and meningeal CAA on a 0-3 scale, capillary CAA as present/absent and vasculopathy on 0-2 scale, in the 4 cortical lobes that were scored separately. A further assessment involving three centres was then undertaken. Neuropathologists in three centres (Bristol, Oxford and Sheffield) independently scored sections from 75 cases (25 from each centre) and high inter-rater reliability was demonstrated. Stage two used the results of the three-centre assessment to validate the protocol by investigating previously described associations between APOE genotype (previously determined), and both CAA and vasculopathy. Association of capillary CAA with or without arteriolar CAA with APOE ε4 was confirmed. However APOE ε2 was also found to be a strong risk factor for the development of CAA, not only in AD but also in elderly non-demented controls. Further validation of this protocol and scoring scheme is encouraged, to aid its wider adoption to facilitate collaborative and replication studies of CAA.

Distribution of the branched chain aminotransferase proteins in the human brain and their role in glutamate regulation.

The branched chain aminotransferase enzymes (BCAT) serve as nitrogen donors for the production of 30% of de novo glutamate synthesis in rat brain. Despite the importance of this major metabolite and excitatory neurotransmitter, the distribution of BCAT proteins in the human brain (hBCAT) remains unreported. We have studied this and report, for the first time, that the mitochondrial isoform, hBCATm is largely confined to vascular endothelial cells, whereas the cytosolic hBCATc is restricted to neurons. The majority of hBCATc-labelled neurons were either GABA-ergic or glutamatergic showing both cell body and axonal staining indicating a role for hBCATc in both glutamate production and glutamate release during excitation. Strong staining in hormone secreting cells suggests a further role for the transaminases in hormone regulation potentially similar to that proposed for insulin secretion. Expression of hBCATm in the endothelial cells of the vasculature demonstrates for the first time that glutamate could be metabolized by aminotranferases in these cells. This has important implications given that the dysregulation of glutamate metabolism, leading to glutamate excitotoxicity, is an important contributor to the pathogenesis of several neurodegenerative conditions, where the role of hBCATm in metabolizing excess glutamate may factor more prominently.

LRP-1 variation is not associated with risk of Alzheimer's disease.

Alzheimer's disease (AD) is characterised by the extensive deposition of amyloid beta (Aß) within the parenchyma and vasculature of the brain. It is hypothesised that a dysfunction in Aß degradation and/or its removal from the brain may result in accumulation as plaques. Low density lipoprotein receptor-related protein-1 (LRP-1) is a multifunctional receptor shown to be involved in cholesterol metabolism but also the removal of Aß from the brain. Its ability to transport Aß from the brain to the periphery has made it an attractive candidate for involvement in Alzheimer's disease (AD). We have assessed the frequencies of 9 tag- SNPs and the commonly studied synonymous SNP within exon 3 (rs1799986) in a multi-centre AD/control cohort and performed haplotype analysis. We found no evidence from a combined total of 412 controls and 1057 AD patients to support the involvement of LRP-1 variation, including the most commonly studied variant in rs1799986 in conferring genetic susceptibility to increased risk of AD.

Insights into the pathogenesis and pathogenicity of cerebral amyloid angiopathy.

Amyloid-beta (Abeta) cerebral amyloid angiopathy (CAA) affects most Alzheimer's disease (AD) patients and ~30% of otherwise-normal elderly people. APOE epsilon 4 is a major risk factor for CAA in AD. Neurons are probably the source of the vascular Abeta. CAA develops when Abeta is deposited in the vessel walls along or across which it normally passes into the CSF and bloodstream. Vascular deposition is facilitated by factors that increase Abeta40:Abeta42, impede perivascular passage of Abeta or raise its concentration. The levels of some Abeta-degrading enzymes are reduced in AD patients with CAA. However, angiotensin-converting enzyme activity is increased and may act via angiotensin II to increase transforming growth factor beta1, a potent inducer of ECM synthesis. CAA is a cause of intracerebral haemorrhage and cerebral ischaemic damage. In AD, neuritic degeneration is accentuated around Abeta-laden vessels. Rarely, CAA is associated with angiitis. The balance between parenchymal and cerebrovascular degradation of Abeta, and regulation of perivascular extracellular matrix production, are likely to be key determinants of Abeta distribution and pathogenicity within the brain.

Cholinesterase inhibitors may increase phosphorylated tau in Alzheimer's disease.

Cholinesterase inhibitors (ChEIs) are widely used for the symptomatic treatment of Alzheimer's disease (AD). In vitro and in animal studies, ChEIs have been shown to influence the processing of Abeta and the phosphorylation of tau, proteins that are the principal constituents of the plaques and neurofibrillary tangles, respectively, in AD brain. However, little is known about the effects of these drugs on Abeta and tau pathology in AD. Using avidin-biotin immunohistochemistry and computer-assisted image analysis, we compared Abeta and tau loads in the frontal and temporal cortices of 72 brains from matched cohorts of AD patients who had or had not received ChEIs. Patients treated with ChEIs had accumulated significantly more phospho-tau in their cerebral cortex than had untreated patients (P = 0.004). Abeta accumulation was reduced but not significantly. These data raise the possibility that increased tau phosphorylation may influence long-term clinical responsiveness to ChEIs.

Phosphorylated Smad 2/3 colocalizes with phospho-tau inclusions in Pick disease, progressive supranuclear palsy, and corticobasal degeneration but not with alpha-synuclein inclusions in multiple system atrophy or dementia with Lewy bodies.

Impaired transduction of transforming growth factor-beta signaling has recently been implicated in Alzheimer disease. Transforming growth factor-beta signals are transduced by Smads, which are phosphorylated and translocated to the nucleus, where they initiate gene transcription. In Alzheimer disease, neurofibrillary tangles sequester phosphorylated Smad 2/3 (pSmad2/3) and reduce its nuclear translocation. We have now investigated the relationship between pSmad2/3 and phospho-tau in 3 other tauopathies, Pick disease, progressive supranuclear palsy, and corticobasal degeneration, and in 2 alpha-synucleinopathies, dementia with Lewy bodies and multiple system atrophy. In Pick disease, progressive supranuclear palsy, and corticobasal degeneration, pSmad2/3 was demonstrated in neuronal and glial nuclei but also colocalized with cytoplasmic tau inclusions. No pSmad2/3 was detected in glial cytoplasmic inclusions in multiple system atrophy or in Lewy bodies in dementia with Lewy bodies. Our data indicate that phospho-tau but not alpha-synuclein cytoplasmic inclusions bind pSmad2/3. The preservation of neuronal nuclear pSmad2/3 in Pick disease, progressive supranuclear palsy, and corticobasal degeneration suggests that cytoplasmic sequestration of pSmad2/3 is likely to have less impact on transforming growth factor-beta signal transduction in these diseases than in Alzheimer disease.