Michael G. Heckman

Endoscopic assessment of the oesophageal features of eosinophilic oesophagitis: validation of a novel classification and grading system

Objective Abnormalities are commonly identified during endoscopy in eosinophilic oesophagitis (EoE). There is no standardised classification to describe these features. This study aimed to evaluate the interobserver agreement of a grading system for the oesophageal features of EoE. Method The proposed system incorporated the grading of four major oesophageal features (rings, furrows, exudates, oedema) and the presence of additional features of narrow calibre oesophagus, feline oesophagus, stricture and crepe paper oesophagus. Endoscopic videos from 25 patients with EoE and controls were reviewed by 21 gastroenterologists. Interobserver agreement was assessed by estimating multi-rater κ and the proportion of pairwise agreement. Results Using the original grading system, agreement for rings, furrows and exudates was moderate (κ=0.38–0.46, 56–65% agreement) but poor for oedema (κ=0.23, 51% agreement). Identification of narrow calibre oesophagus had fair agreement (κ=0.30, 74% agreement) while feline oesophagus had poor agreement (κ=0.15, 68% agreement). After collapsing the severity grading for oedema and furrows and eliminating poorly performing features of feline oesophagus and narrow calibre oesophagus, a modified grading system demonstrated good agreement for the four major features of EoE (κ=0.40–0.54, 71–81% agreement) and additional features of stricture and crepe paper oesophagus (κ=0.52 and 0.58, 79% and 92% agreement). Conclusions The proposed system for endoscopically-identified oesophageal features of EoE defines common nomenclature and severity scores for the assessment of EoE disease activity. The system has good interobserver agreement among practising and academic gastroenterologists.

α-Synuclein promoter confers susceptibility to Parkinson's disease

Familial Parkinsons disease (PD) has been linked to missense and genomic multiplication mutations of the α‐synuclein gene (SNCA). Genetic variability within SNCA has been implicated in idiopathic PD in many populations. We now confirm and extend these findings, within a Belgian sample, using a high‐resolution map of genetic markers across the SNCA locus. Our study implicates the SNCA promoter in susceptibility to PD, and more specifically defines a minimum promoter haplotype, spanning approximately 15.3kb of sequence, which is overrepresented in patients. Our findings represent a biomarker for PD and may have implications for patient diagnosis, longitudinal evaluation, and treatment. Ann Neurol 2004;56:591–595

Association of LRRK2 exonic variants with susceptibility to Parkinson's disease: A case-control study

BACKGROUND Background The leucine-rich repeat kinase 2 gene (LRRK2) harbours highly penetrant mutations that are linked to familial parkinsonism. However, the extent of its polymorphic variability in relation to risk of Parkinsons disease (PD) has not been assessed systematically. We therefore assessed the frequency of LRRK2 exonic variants in individuals with and without PD, to investigate the role of the variants in PD susceptibility. METHODS LRRK2 was genotyped in patients with PD and controls from three series (white, Asian, and Arab-Berber) from sites participating in the Genetic Epidemiology of Parkinsons Disease Consortium. Genotyping was done for exonic variants of LRRK2 that were identified through searches of literature and the personal communications of consortium members. Associations with PD were assessed by use of logistic regression models. For variants that had a minor allele frequency of 0·5% or greater, single variant associations were assessed, whereas for rarer variants information was collapsed across variants. FINDINGS 121 exonic LRRK2 variants were assessed in 15 540 individuals: 6995 white patients with PD and 5595 controls, 1376 Asian patients and 962 controls, and 240 Arab-Berber patients and 372 controls. After exclusion of carriers of known pathogenic mutations, new independent risk associations were identified for polymorphic variants in white individuals (M1646T, odds ratio 1·43, 95% CI 1·15-1·78; p=0·0012) and Asian individuals (A419V, 2·27, 1·35-3·83; p=0·0011). A protective haplotype (N551K-R1398H-K1423K) was noted at a frequency greater than 5% in the white and Asian series, with a similar finding in the Arab-Berber series (combined odds ratio 0·82, 0·72-0·94; p=0·0043). Of the two previously reported Asian risk variants, G2385R was associated with disease (1·73, 1·20-2·49; p=0·0026), but no association was noted for R1628P (0·62, 0·36-1·07; p=0·087). In the Arab-Berber series, Y2189C showed potential evidence of risk association with PD (4·48, 1·33-15·09; p=0·012). INTERPRETATION The results for LRRK2 show that several rare and common genetic variants in the same gene can have independent effects on disease risk. LRRK2, and the pathway in which it functions, is important in the cause and pathogenesis of PD in a greater proportion of patients with this disease than previously believed. These results will help discriminate those patients who will benefit most from therapies targeted at LRRK2 pathogenic activity. FUNDING Michael J Fox Foundation and National Institutes of Health.

Comparison of Probe-Based Confocal Laser Endomicroscopy With Virtual Chromoendoscopy for Classification of Colon Polyps

BACKGROUND & AIMS Probe-based confocal laser endomicroscopy (pCLE) allows in vivo imaging of tissue at micron resolution. Virtual chromoendoscopy systems, such as Fujinon intelligent color enhancement and narrow band imaging, also have potential to differentiate neoplastic colorectal lesions. The accuracy of these systems in clinical practice is, however, unknown. Our primary aim was to compare sensitivity and specificity of pCLE to virtual chromoendoscopy for classification of colorectal polyps using histopathology as a gold standard. A secondary aim was to compare sensitivity and specificity of pCLE to virtual chromoendoscopy using a modified gold standard that assumed that all polyps >/=10 mm had malignant potential and were considered neoplastic or high risk. METHODS Patients underwent colonoscopy using high-resolution colonoscopes. The surface pit pattern was determined with NBI or FICE in all patients. Confocal images were recorded and subsequently analyzed offline, blinded to the endoscopic characteristics and histopathology. Each polyp was diagnosed as benign or neoplastic based on confocal features according to modified Mainz criteria. RESULTS A total of 119 polyps (81 neoplastic, 38 hyperplastic) from 75 patients was assessed. The pCLE had higher sensitivity compared to virtual chromoendoscopy when considering histopathology as gold standard (91% vs 77%; P = .010) and modified gold standard (88% vs 76%; P = .037). There was no statistically significant difference in specificity between pCLE and virtual chromoendoscopy when considering histopathology or modified gold standard. CONCLUSIONS Confocal endomicroscopy demonstrated higher sensitivity with similar specificity in classification of colorectal polyps. These new methods may replace the need for ex vivo histological confirmation of small polyps, but further studies are warranted.

Association between repeat sizes and clinical and pathological characteristics in carriers of C9ORF72 repeat expansions (Xpansize-72): a cross-sectional cohort study

BACKGROUND Hexanucleotide repeat expansions in chromosome 9 open reading frame 72 (C9ORF72) are the most common known genetic cause of frontotemporal dementia (FTD) and motor neuron disease (MND). We assessed whether expansion size is associated with disease severity or phenotype. METHODS We did a cross-sectional Southern blot characterisation study (Xpansize-72) in a cohort of individuals with FTD, MND, both these diseases, or no clinical phenotype. All participants had GGGGCC repeat expansions in C9ORF72, and high quality DNA was available from one or more of the frontal cortex, cerebellum, or blood. We used Southern blotting techniques and densitometry to estimate the repeat size of the most abundant expansion species. We compared repeat sizes between different tissues using Wilcoxon rank sum and Wilcoxon signed rank tests, and between disease subgroups using Kruskal-Wallis rank sum tests. We assessed the association of repeat size with age at onset and age at collection using a Spearmans test of correlation, and assessed the association between repeat size and survival after disease onset using Cox proportional hazards regression models. FINDINGS We included 84 individuals with C9ORF72 expansions: 35 had FTD, 16 had FTD and MND, 30 had MND, and three had no clinical phenotype. We focused our analysis on three major tissue subgroups: frontal cortex (available from 41 patients [21 with FTD, 11 with FTD and MND, and nine with MND]), cerebellum (40 patients [20 with FTD, 12 with FTD and MND, and eight with MND]), and blood (47 patients [15 with FTD, nine with FTD and MND, and 23 with MND] and three carriers who had no clinical phenotype). Repeat lengths in the cerebellum were smaller (median 12·3 kb [about 1667 repeat units], IQR 11·1-14·3) than those in the frontal cortex (33·8 kb [about 5250 repeat units], 23·5-44·9; p<0·0001) and those in blood (18·6 kb [about 2717 repeat units], 13·9-28·1; p=0·0002). Within these tissues, we detected no difference in repeat length between disease subgroups (cerebellum p=0·96, frontal cortex p=0·27, blood p=0·10). In the frontal cortex of patients with FTD, repeat length correlated with age at onset (r=0·63; p=0·003) and age at sample collection (r=0·58; p=0·006); we did not detect such a correlation in samples from the cerebellum or blood. When assessing cerebellum samples from the overall cohort, survival after disease onset was 4·8 years (IQR 3·0-7·4) in the group with expansions greater than 1467 repeat units (the 25th percentile of repeat lengths) versus 7·4 years (6·3-10·9) in the group with smaller expansions (HR 3·27, 95% CI 1·34-7·95; p=0·009). INTERPRETATION We detected substantial variation in repeat sizes between samples from the cerebellum, frontal cortex, and blood, and longer repeat sizes in the cerebellum seem to be associated with a survival disadvantage. Our findings indicate that expansion size does affect disease severity, which--if replicated in other cohorts--could be relevant for genetic counselling. FUNDING The ALS Therapy Alliance, the National Institute of Neurological Disorders and Stroke, the National Institute on Aging, the Arizona Department of Health Services, the Arizona Biomedical Research Commission, and the Michael J Fox Foundation for Parkinsons Research.

Immunoreactivity of the phosphorylated axonal neurofilament H subunit (pNF-H) in blood of ALS model rodents and ALS patients: evaluation of blood pNF-H as a potential ALS biomarker

Levels of neurofilament subunits, potential biomarkers of motor axon breakdown, are increased in amyotrophic lateral sclerosis (ALS) patient’s CSF but data on blood are not available. We measured blood levels of the phosphorylated axonal form of neurofilament H (pNF‐H) by ELISA in transgenic rodent models of superoxide dismutase 1 (SOD1) ALS, and in 20 ALS patients and 20 similar aged controls monthly for 4 months. All symptomatic rodent ALS models showed robust levels of blood pNF‐H, while control rodents or mice transgenic for unmutated SOD1 showed no detectable blood pNF‐H. Average pNF‐H levels in the G93A SOD1 mouse progressively increased from day 74 through death (day ∼130). Median blood pNF‐H level in ALS patients was 2.8‐fold higher than controls (p < 0.001). Median ALSFRS‐R declined a median of 0.8 pt/month (p < 0.001); higher baseline pNF‐H level appeared to be associated with faster ALSFRS‐R decline over 4 months (p = 0.087). The median rate of decline in ALSFRS‐R was 1.9 pt/month in patients with baseline pNF‐H levels above the median pNF‐H value of 0.53 ng/mL; ALSFRS‐R declined at a median of 0.6 pt/month in patients below this level. The pNF‐H levels were relatively stable month to month in individual patients, raising questions regarding the molecular pathogenesis of ALS. Baseline control human pNF‐H levels were higher in men than women and increased minimally over time. These data suggest that blood pNF‐H can be used to monitor axonal degeneration in ALS model rodents and support further study of this protein as a potential biomarker of disease prognosis in ALS patients.

SALVAGE RADIOTHERAPY FOR RISING PROSTATE-SPECIFIC ANTIGEN LEVELS AFTER RADICAL PROSTATECTOMY FOR PROSTATE CANCER: DOSE-RESPONSE ANALYSIS

PURPOSE To investigate the association between external beam radiotherapy (EBRT) dose and biochemical failure (BcF) of prostate cancer in patients who received salvage prostate bed EBRT for a rising prostate-specific antigen (PSA) level after radical prostatectomy. METHODS AND MATERIALS We evaluated patients with a rising PSA level after prostatectomy who received salvage EBRT between July 1987 and October 2007. Patients receiving pre-EBRT androgen suppression were excluded. Cox proportional hazards models were used to investigate the association between EBRT dose and BcF. Dose was considered as a numeric variable and as a categoric variable (low, <64.8 Gy; moderate, 64.8-66.6 Gy; high, >66.6 Gy). RESULTS A total of 364 men met study selection criteria and were followed up for a median of 6.0 years (range, 0.1-19.3 years). Median pre-EBRT PSA level was 0.6 ng/mL. The estimated cumulative rate of BcF at 5 years after EBRT was 50% overall and 57%, 46%, and 39% for the low-, moderate-, and high-dose groups, respectively. In multivariable analysis adjusting for potentially confounding variables, there was evidence of a linear trend between dose and BcF, with risk of BcF decreasing as dose increased (relative risk [RR], 0.77 [5.0-Gy increase]; p = 0.05). Compared with the low-dose group, there was evidence of a decreased risk of BcF for the high-dose group (RR, 0.60; p = 0.04), but no difference for the moderate-dose group (RR, 0.85; p = 0.41). CONCLUSIONS Our results suggest a dose response for salvage EBRT. Doses higher than 66.6 Gy result in decreased risk of BcF.

High-Definition Colonoscopy Detects Colorectal Polyps at a Higher Rate Than Standard White-Light Colonoscopy

BACKGROUND & AIMS Adenoma detection rates might be improved through use of high-definition colonoscopy, which can detect subtle mucosal changes. We investigated whether the use of high-definition white-light (HDWL) colonoscopy resulted in a higher rate of adenoma detection than standard-definition white-light (SDWL) colonoscopy in a clinical practice setting. METHODS This retrospective study included 2430 patients who underwent colonoscopies from September 2006 to December 2007; 1226 received SDWL colonoscopy and 1204 received HDWL colonoscopy. We analyzed data from consecutive screening, surveillance, and diagnostic colonoscopies, comparing adenoma and overall polyp detection between procedures. Potentially confounding variables were controlled using multivariable logistic regression analysis. RESULTS The adenoma detection rate was higher among patients who underwent HDWL compared with SDWL colonoscopies (28.8% vs 24.3%; P = .012), as was the polyp detection rate (42.2% vs 37.8%; P = .026). These findings remained after adjustments for potentially confounding variables (P = .018 and .022, respectively). CONCLUSIONS In a general clinical practice setting, HDWL colonoscopy resulted in a higher adenoma detection rate compared with SDWL colonoscopy. The use of SDWL colonoscopy could reduce the number of missed adenomas and the subsequent risk for colorectal cancer.

LINGO1 and LINGO2 variants are associated with essential tremor and Parkinson disease.

Genetic variation in the leucine-rich repeat and Ig domain containing 1 gene (LINGO1) was recently associated with an increased risk of developing essential tremor (ET) and Parkinson disease (PD). Herein, we performed a comprehensive study of LINGO1 and its paralog LINGO2 in ET and PD by sequencing both genes in patients (ET, n = 95; PD, n = 96) and by examining haplotype-tagging single-nucleotide polymorphisms (tSNPs) in a multicenter North American series of patients (ET, n = 1,247; PD, n = 633) and controls (n = 642). The sequencing study identified six novel coding variants in LINGO1 (p.S4C, p.V107M, p.A277T, p.R423R, p.G537A, p.D610D) and three in LINGO2 (p.D135D, p.P217P, p.V565V), however segregation analysis did not support pathogenicity. The association study employed 16 tSNPs at the LINGO1 locus and 21 at the LINGO2 locus. One variant in LINGO1 (rs9652490) displayed evidence of an association with ET (odds ratio (OR) = 0.63; P = 0.026) and PD (OR = 0.54; P = 0.016). Additionally, four other tSNPs in LINGO1 and one in LINGO2 were associated with ET and one tSNP in LINGO2 associated with PD (P < 0.05). Further analysis identified one tSNP in LINGO1 and two in LINGO2 which influenced age at onset of ET and two tSNPs in LINGO1 which altered age at onset of PD (P < 0.05). Our results support a role for LINGO1 and LINGO2 in determining risk for and perhaps age at onset of ET and PD. Further studies are warranted to confirm these findings and to determine the pathogenic mechanisms involved.

Diagnostic Accuracy of Probe-Based Confocal Laser Endomicroscopy and Narrow Band Imaging for Small Colorectal Polyps: A Feasibility Study

OBJECTIVES:Probe-based confocal laser endomicroscopy (pCLE) allows real-time in-vivo microscopic imaging of tissue. Narrow band imaging (NBI) can also classify colorectal lesions. Both systems may allow accurate optical diagnosis of small (6–9 mm) and diminutive (1–5 mm) polyps without histopathology. This study assesses the accuracy of pCLE and NBI for prediction of histology.METHODS:Participants underwent high-definition colonoscopy. The surface pit pattern of all polyps (1–9 mm) was determined in vivo using NBI. Confocal videos were obtained after administration of IV fluorescein. Recorded videos were subsequently analyzed offline, blinded to endoscopic characteristics, and histopathology. Confocal images were classified as neoplastic and non-neoplastic according to the Miami classification system.RESULTS:A total of 130 polyps (58 neoplastic, 72 non-neoplastic, mean size 4.6 mm) from 65 patients were assessed. Assuming histopathology as gold standard, pCLE had higher sensitivity than NBI (86% vs. 64%, P=0.008), with lower specificity (78% vs. 92%, p=0.027) and similar overall accuracy (82% vs. 79%, P=0.59). When 65 high-confidence cases were analyzed (polyps diagnosed identically with pCLE and NBI and with high-quality confocal videos), sensitivity and specificity were 94 and 97%.CONCLUSIONS:pCLE demonstrated higher sensitivity in predicting histology of small polyps compared with NBI, whereas NBI had higher specificity. When used in combination, the accuracy of pCLE and NBI was extremely high, approaching the accuracy of histopathology. Together, they may reduce the need for histological examination. However, further studies are warranted to evaluate the role of these techniques, especially in the population-based colon cancer screening.