Prospective Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pathophysiol. Aug 15, 2017; 8(3): 127-132
Published online Aug 15, 2017. doi: 10.4291/wjgp.v8.i3.127
Assessment of serum angiogenic factors as a diagnostic aid for small bowel angiodysplasia in patients with obscure gastrointestinal bleeding and anaemia
Grainne Holleran, Mary Hussey, Sinead Smith, Deirdre McNamara
Grainne Holleran, Mary Hussey, Sinead Smith, Deirdre McNamara, Department of Clinical Medicine, Trinity Centre for Health Sciences, Tallaght Hospital, 24 Dublin, Ireland
Author contributions: Holleran G and McNamara D designed research; Holleran G, Hussey M and Smith S Performed research; Holleran G, Smith S and McNamara D analyzed data; Smith S contributed reagents and analytical tools; Holleran G and McNamara D wrote the paper.
Institutional review board statement: Full ethical approval was obtained from the Tallaght Hospital/St James’s Hospital Joint research Ethics committee.
Informed consent statement: Written informed consent was obtained from all patients prior to inclusion.
Conflict-of-interest statement: None of the authors had any conflicts of interest to declare.
Data sharing statement: There is no additional data available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Grainne Holleran, MD, Department of Clinical Medicine, Trinity Centre for Health Sciences, Tallaght Hospital, 24 Dublin, Ireland. hollerag@tcd.ie
Telephone: +353-18963844
Received: December 16, 2016
Peer-review started: December 20, 2016
First decision: March 6, 2017
Revised: March 31, 2017
Accepted: May 18, 2017
Article in press: May 19, 2017
Published online: August 15, 2017
Processing time: 240 Days and 3.3 Hours
Abstract
AIM

To assess the use of serum levels of angiopoietin-1 (Ang1), Ang2 and tumor necrosis factor-α (TNFα) as predictive factors for small bowel angiodysplasia (SBA).

METHODS

Serum samples were collected from patients undergoing capsule endoscopy for any cause of obscure gastrointestinal bleeding (OGIB) or anaemia. Based on small bowel findings patients were divided into 3 groups: (1) SBA; (2) other bleeding causes; and (3) normal, according to diagnosis. Using ELISA technique we measured serum levels of Ang1, Ang2 and TNFα and compared mean and median levels between the groups based on small bowel diagnosis. Using receiver operator curve analysis we determined whether any of the factors were predictive of SBA.

RESULTS

Serum samples were collected from a total of 120 patients undergoing capsule endoscopy for OGIB or anaemia: 40 with SBA, 40 with other causes of small bowel bleeding, and 40 with normal small bowel findings. Mean and median serum levels were measured and compared between groups; patients with SBA had significantly higher median serum levels of Ang2 (3759 pg/mL) compared to both other groups, with no significant differences in levels of Ang1 or TNFα based on diagnosis. There were no differences in Ang2 levels between the other bleeding causes (2261 pg/mL) and normal (2620 pg/mL) groups. Using Receiver Operator Curve analysis, an Ang2 level of > 2600 pg/mL was found to be predictive of SBA, with an area under the curve of 0.7. Neither Ang1 or TNFα were useful as predictive markers.

CONCLUSION

Elevations in serum Ang2 are specific for SBA and not driven by other causes of bleeding and anaemia. Further work will determine whether Ang2 is useful as a diagnostic or prognostic marker for SBA.

Keywords: Angiodysplasia; Small intestinal bleeding; Capsule endoscopy; Angiogenic factors; Angiopoietin-2

Core tip: Small bowel angiodysplasia (SBA) is an important cause of obscure gastrointestinal bleeding and anaemia but can be difficult to diagnose. This paper assesses the use of novel serum angiogenic factors associated with SBA as potential diagnostic aids. The study has identified a cut-off serum level of Ang2 of 2600 pg/mL which may be useful in predicting patients with the condition. Further studies will be required to determine its use in clinical practice but it may represent a major advancement in the identification of a diagnostic and prognostic marker for angiodysplasia, and also in determining the underlying pathophysiology of the condition.