Standardizing Randomized Controlled Trials in Celiac Disease: An International Multidisciplinary Appropriateness Study.

BACKGROUND & AIMS: There is a need to develop safe and effective pharmacologic options for the treatment of celiac disease (CeD); however, consensus on the appropriate design and configuration of randomized controlled trials (RCTs) in this population is lacking. METHODS: A 2-round modified Research and Development/University of California Los Angeles Appropriateness Method study was conducted. Eighteen gastroenterologists (adult and pediatric) and gastrointestinal pathologists voted on statements pertaining to the configuration of CeD RCTs, inclusion and exclusion criteria, gluten challenge, and trial outcomes. Two RCT designs were considered, representing the following distinct clinical scenarios for which pharmacotherapy may be used: trials incorporating a gluten challenge to simulate exposure; and trials evaluating reversal of histologic changes, despite attempted adherence to a gluten-free diet. Each statement was rated as appropriate, uncertain, or inappropriate, using a 9-point Likert scale. RESULTS: For trials evaluating prevention of relapse after gluten challenge, participants adherent to a gluten-free diet for 12 months or more with normal or near-normal-sized villi should be enrolled. Gluten challenge should be FODMAPS (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) free, and efficacy evaluated using histology with a secondary patient-reported outcome measure. For trials evaluating reversal of villus atrophy, the panel voted it appropriate to enroll participants with a baseline villus height to crypt depth ratio ≤2 and measure efficacy using a primary histologic end point. Guidance for measuring histologic, endoscopic, and patient-reported outcomes in adult and pediatric patients with CeD are provided, along with recommendations regarding the merits and limitations of different end points. CONCLUSIONS: We developed standardized recommendations for clinical trial design, eligibility criteria, outcome measures, gluten challenge, and disease evaluations for RCTs in patients with CeD.

An Expert Consensus to Standardize Assessment of Bowel Cleansing for Clinical Trials of Bowel Preparations for Crohn's Disease.

BACKGROUND: Despite regular need for colonoscopy in patients with Crohn's disease (CD), the efficacy and tolerability of bowel preparation (BP) agents is rarely assessed in this population. Assessing BP quality with existing scales may be challenging in CD due to presence of inflammation, bowel resection, and strictures. AIMS: To provide recommendations for assessing BP quality in clinical trials for CD using a modified Research and Development/University of California, Los Angeles appropriateness process. METHODS: Based on systematic reviews and a literature search, 110 statements relating to BP quality assessment in CD were developed. A panel of 15 gastroenterologists rated the statements as appropriate, uncertain, or inappropriate using a 9-point Likert scale. RESULTS: Panelists considered it appropriate that central readers, either alone or with local assessment, score BP quality in clinical trials. Central readers should be trained on scoring BP quality and local endoscopists on performing high-quality video recording. Both endoscope insertion and withdrawal phases should be reviewed to score BP quality in each colonic segment and segments should align with endoscopic disease activity indices. The Harefield Cleansing Scale and the Boston Bowel Preparation Scale were considered appropriate. The final score should be calculated as the average of all visualized segments. Both total and worst segment scores should also be assessed. CONCLUSIONS: We developed a framework for assessing BP quality in patients with CD based on expert feedback. This framework could support the development or refinement of BP quality scales and the integration of BP quality assessment in future CD studies.

A systematic review of measurement of endoscopic disease activity and mucosal healing in Crohn's disease: recommendations for clinical trial design.

BACKGROUND: Crohn's disease (CD) is a chronic idiopathic inflammatory disorder of the gastrointestinal tract. Recently, mucosal healing has been proposed as a goal of therapy because clinical symptoms are subjective. Evaluative indices that measure endoscopic disease activity are required to define mucosal healing for clinical trials. The primary objective of this systematic review was to assess the existing evaluative indices that measure disease activity in CD and evaluate their role as outcome measures in clinical trials. METHODS: A systematic literature review was performed using MEDLINE (Ovid), EMBASE (Ovid), PubMed, the Cochrane Library (CENTRAL), and DDW abstracts to identify randomized controlled trials and controlled clinical trials that used a relevant evaluative index from inception to February 2013. The data obtained from these trials were reviewed and summarized. RESULTS: The initial literature searches identified 2300 citations. After duplicates were removed, 1454 studies remained. After application of the apriori inclusion and exclusion criteria, 109 articles were included and 3 were identified with handsearches. In total, 9 evaluative indices for CD were identified and reviewed. The Crohn's Disease Endoscopic Index of Severity (CDEIS) and the Simple Endoscopic Score in Crohn's Disease (SES-CD) are indices with the most extensively described operating properties. CONCLUSIONS: Both the endoscopic evaluative instrument selected and the definition chosen for mucosal healing affect the validity of assessing endoscopic disease activity during a clinical trial for CD. Currently, the CDEIS and SES-CD have the most data regarding operating properties; however, further validation is required.

Netrin 1 and Dcc regulate oligodendrocyte process branching and membrane extension via Fyn and RhoA.

The molecular mechanisms underlying the elaboration of branched processes during the later stages of oligodendrocyte maturation are not well understood. Here we describe a novel role for the chemotropic guidance cue netrin 1 and its receptor deleted in colorectal carcinoma (Dcc) in the remodeling of oligodendrocyte processes. Postmigratory, premyelinating oligodendrocytes express Dcc but not netrin 1, whereas mature myelinating oligodendrocytes express both. We demonstrate that netrin 1 promotes process extension by premyelinating oligodendrocytes in vitro and in vivo. Addition of netrin 1 to mature oligodendrocytes in vitro evoked a Dcc-dependent increase in process branching. Furthermore, expression of netrin 1 and Dcc by mature oligodendrocytes was required for the elaboration of myelin-like membrane sheets. Maturation of oligodendrocyte processes requires intracellular signaling mechanisms involving Fyn, focal adhesion kinase (FAK), neuronal Wiscott-Aldrich syndrome protein (N-WASP) and RhoA; however, the extracellular cues upstream of these proteins in oligodendrocytes are poorly defined. We identify a requirement for Src family kinase activity downstream of netrin-1-dependent process extension and branching. Using oligodendrocytes derived from Fyn knockout mice, we demonstrate that Fyn is essential for netrin-1-induced increases in process branching. Netrin 1 binding to Dcc on mature oligodendrocytes recruits Fyn to a complex with the Dcc intracellular domain that includes FAK and N-WASP, resulting in the inhibition of RhoA and inducing process remodeling. These findings support a novel role for netrin 1 in promoting oligodendrocyte process branching and myelin-like membrane sheet formation. These essential steps in oligodendroglial maturation facilitate the detection of target axons, a key step towards myelination.

Maintenance of axo-oligodendroglial paranodal junctions requires DCC and netrin-1.

Paranodal axoglial junctions are essential for the segregation of myelinated axons into distinct domains and efficient conduction of action potentials. Here, we show that netrin-1 and deleted in colorectal cancer (DCC) are enriched at the paranode in CNS myelin. We then address whether netrin-1 signaling influences paranodal adhesion between oligodendrocytes and axons. In the absence of netrin-1 or DCC function, oligodendroglial paranodes initially develop and mature normally but later become disorganized. Lack of DCC or netrin-1 resulted in detachment of paranodal loops from the axonal surface and the disappearance of transverse bands. Furthermore, the domain organization of myelin is compromised in the absence of netrin-1 signaling: K+ channels inappropriately invade the paranodal region, and the normally restricted paranodal distribution of Caspr expands longitudinally along the axon. Our findings identify an essential role for netrin-1 and DCC regulating the maintenance of axoglial junctions.

An adult rat spinal cord contusion model of sensory axon degeneration: the estrus cycle or a preconditioning lesion do not affect outcome.

A therapeutic strategy for acute spinal cord injury would be to reduce the progressive degeneration and disconnection of axons from their targets. Here, we describe a model to evaluate degeneration of the ascending sensory projections to the nuclei in the medulla following graded spinal cord contusions in adult female Sprague-Dawley rats. Cholera toxin B (CTB) labeling from the sciatic nerve of naive rats revealed effective labeling of the terminal fibers in the gracile nucleus at 3 days post-injection and a subpopulation of rapidly transporting fibers after 1 day. Seven days after contusions using the Infinite Horizon impactor the area of CTB-labeled terminal fibers had a negative correlation with increasing impact force. Moderate spinal contusions of around 150 kilodyne (kdyn or 0.15 x 10(-3) newton) caused a reduction to 40% in the fiber area which will enable the identification of protective as well as detrimental drugs and post-injury mechanisms. A preconditioning injury of the sciatic nerve reportedly can enhance growth of sensory axons but did not affect the terminal fiber area in the gracile nucleus. Estrogen and progesterone are protective in various systems and could therefore influence experimental outcomes when using females. However, the phase of the estrus cycle at the time of contusion or during the post-injury time did not affect the outcome of the contusion, indicating that female rats may be used without consideration of the estrus cycle. This model can readily be used to evaluate pharmacological agents for protection of sensory axons and pathophysiological mechanisms of their degeneration.

Long distance selective fiber outgrowth of transplanted hNT neurons in white matter tracts of the adult rat brain.

Terminally differentiated neurons derived from a human teratocarcinoma cell line (NT2N or hNT neurons) are promising as a cell source for transplantation, as they have been shown to be safe for transplantation in humans. We have shown previously that hNT neurons can express a catecholaminergic phenotype in a rat Parkinson model. In this study, we investigated the long-term survival and ability of hNT neurons to express tyrosine hydroxylase and reconstruct the dopamine-denervated nigrostriatal pathway. Hemiparkinsonian rats received grafts of 400,000 viable hNT neurons into each of the denervated striatum and substantia nigra. Robust hNT grafts were detected up to 24 weeks posttransplantation, although few cells expressed tyrosine hydroxylase. Many hNT fibers were often associated with ipsilateral and contralateral white matter tracts--corpus callosum, rostral migratory stream, optic tract, and external capsule. Fewer fibers were associated with the superior cerebellar peduncle, medial lemniscus, and nigrostriatal pathway. Axons also projected into the frontal cortex and extended parallel to the surface of the brain in the superficial cortical layers. These pathways were seen in all grafted animals, suggesting that specific guidance cues exist in the adult brain governing hNT fiber outgrowth. Injured adult axons and transplanted embryonic neuronal axons rarely extend for such distances in the adult nervous system. We propose that elucidating the factors promoting and guiding hNT axonal outgrowth could provide important clues to enhancing regeneration and target reinnervation in the adult brain, two factors of critical importance for cell restoration strategies aimed at brain repair.