Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 Jun;16(6):1029-39.
doi: 10.1002/ibd.21150.

Angiopoietin-2 in experimental colitis

Vijay C Ganta  1 , Walter Cromer, Ginny L Mills, James Traylor, Merilyn Jennings, Sarah Daley, Benjamin Clark, J Michael Mathis, Michael Bernas, Moheb Boktor, Paul Jordan, Marlys Witte, J Steven Alexander
Affiliations

Angiopoietin-2 in experimental colitis

Vijay C Ganta et al. Inflamm Bowel Dis. 2010 Jun.

Abstract

Background: The pathophysiology of inflammatory bowel disease (IBD) includes leukocyte infiltration, blood and lymphatic remodeling, weight loss and protein enteropathy. The roles of angiopoietin-2 (Ang-2) in initiating gut inflammation, leukocyte infiltration and angiogenesis are not well understood.

Methods: Disease activity index, histopathological scoring, myeloperoxidase assay, immunohistochemistry and sodium dodecyl sulphate- polyacrylamide gel electrophoretic methods were employed in the present study to address the roles of Ang-2 in experimental colitis.

Results: Several important differences were seen in the development of experimental IBD in Ang-2(-/-) mice. Although weight change and disease activity differ only slightly in WT and Ang-2(-/-) + DSS treated mice, leukocyte infiltration, inflammation and blood and lymphatic vessel density is significantly attenuated compared to WT + DSS mice. Gut capillary fragility and water export (stool blood and form) appear significantly earlier in Ang-2(-/-) + DSS mice vs. WT. Colon lengths were also significantly reduced in Ang-2(-/-) and gut histopathology was less severe in Ang-2(-/-) compared to WT + DSS. Lastly, the decrease in serum protein content in WT + DSS was less severe in Ang-2(-/-) + DSS, thus protein losing enteropathy (PLE) a feature of IBD is relieved by Ang-2(-/-).

Conclusion: These data demonstrate that in DSS colitis, Ang-2 mediates inflammatory hemangiogenesis, lymphangiogenesis and neutrophil infiltration to reduce some, but not all clinical features of IBD. The implications for Ang-2 manipulation in the development of IBD and other inflammatory diseases and treatments involving Ang-2 are discussed.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Disease Activity Index (DAI) and weight change
(a) Disease activity. Ang-2-/-/DSS (KO DSS) was significantly different from baseline at day 2 through day 7; WT + DSS-DAI (WT DSS) was not significantly different from baseline until day 5. (b). Weight change. Weight loss in Ang-2-/- + DSS and WT + DSS were both significantly different (*= p<0.05) from baseline at day 5 through day 7 (repeated measures ANOVA, Dunnett’s post-testing). No difference in weight was observed between. Ang-2-/-/DSS; WT + DSS.
Figure 1
Figure 1. Disease Activity Index (DAI) and weight change
(a) Disease activity. Ang-2-/-/DSS (KO DSS) was significantly different from baseline at day 2 through day 7; WT + DSS-DAI (WT DSS) was not significantly different from baseline until day 5. (b). Weight change. Weight loss in Ang-2-/- + DSS and WT + DSS were both significantly different (*= p<0.05) from baseline at day 5 through day 7 (repeated measures ANOVA, Dunnett’s post-testing). No difference in weight was observed between. Ang-2-/-/DSS; WT + DSS.
Figure 2
Figure 2. DSS induced occult blood is exacerbated in Ang-2-/-
Occult blood was detected in the feces of Ang-2-/- + DSS treated mice as early as day 2 through day 7. WT + DSS treated mice did not show evidence of fecal blood until day 3 (through day 7). No significant presence of occult blood was seen in control (WT) or Ang-2-/- (KO Con) mice. (*= p<0.05 vs. control, ** = p<0.01 vs. control)
Figure 3
Figure 3. DSS stool form scoring is exacerbated in Ang-2-/-
Stool form scores were significantly different from baseline by day 2 in Ang-2-/- + DSS. In WT DSS mice significant alterations in stool form were observed from day 3 until day 7 (p<0.05). No significant differnce was observed in WT Con and Ang-/- Con mice.
Figure 4
Figure 4. DSS induced colon shortening is exacerbated in Ang-2-/-
Colon length in Ang-2-/- mice (7.3 +/-0.25 cm) was not significantly different from that in normal controls (7.45 +/- 0.67 cm). Colon length was significantly reduced in WT + DSS colons (to 5.56 +/- 0.13 cm) compared to WT controls (* p<0.05). Colon length was further reduced in Ang-2-/- mice (4.69 +/- 1.25 cm, **p<0.01 vs. Ang-2-/-).
Figure 5
Figure 5. Effects of Ang-2-/- status on histopathological scoring in DSS colitis
(a) Histopathology scores. WT + DSS had a cumulative histopathology score of 21.71±1.10 (Normal score=0, max injury=40), whereas, WT controls were 3±1.22 Ang-2-/-/DSS (15.54±2.06) was significantly reduced (by 28.52%) compared to WT + DSS. Ang-2-/- showed a score of 3 ±1.16. (One-way ANOVA with Bonferroni post-testing. (b). Representative images of hematoxylin/eosin stained tissue from WT Control, Ang-2 KO Con, WT DSS and Ang-2-/- + DSS treated colons.
Figure 5
Figure 5. Effects of Ang-2-/- status on histopathological scoring in DSS colitis
(a) Histopathology scores. WT + DSS had a cumulative histopathology score of 21.71±1.10 (Normal score=0, max injury=40), whereas, WT controls were 3±1.22 Ang-2-/-/DSS (15.54±2.06) was significantly reduced (by 28.52%) compared to WT + DSS. Ang-2-/- showed a score of 3 ±1.16. (One-way ANOVA with Bonferroni post-testing. (b). Representative images of hematoxylin/eosin stained tissue from WT Control, Ang-2 KO Con, WT DSS and Ang-2-/- + DSS treated colons.
Figure 6
Figure 6. Effects of Ang-2-/- status on blood and lymphatic vessel density scoring in DSS colitis
(a) Blood vessel (MECA-32+) immunostained vessels were significantly increased in the colon of WT + DSS (2.19 fold increase over the WT controls). (b) Similarly, lymphatic (VEGFR-3+) vessels showed a 4.9 fold increase from WT to WT + DSS. Increased lymphangiogenesis was significantly reduced in Ang-2-/- and Ang-2-/-/DSS. (c) Histogram of # vessels/section (One-way ANOVA w/Bonferroni post-testing). (Magnification = 200X).
Figure 6
Figure 6. Effects of Ang-2-/- status on blood and lymphatic vessel density scoring in DSS colitis
(a) Blood vessel (MECA-32+) immunostained vessels were significantly increased in the colon of WT + DSS (2.19 fold increase over the WT controls). (b) Similarly, lymphatic (VEGFR-3+) vessels showed a 4.9 fold increase from WT to WT + DSS. Increased lymphangiogenesis was significantly reduced in Ang-2-/- and Ang-2-/-/DSS. (c) Histogram of # vessels/section (One-way ANOVA w/Bonferroni post-testing). (Magnification = 200X).
Figure 6
Figure 6. Effects of Ang-2-/- status on blood and lymphatic vessel density scoring in DSS colitis
(a) Blood vessel (MECA-32+) immunostained vessels were significantly increased in the colon of WT + DSS (2.19 fold increase over the WT controls). (b) Similarly, lymphatic (VEGFR-3+) vessels showed a 4.9 fold increase from WT to WT + DSS. Increased lymphangiogenesis was significantly reduced in Ang-2-/- and Ang-2-/-/DSS. (c) Histogram of # vessels/section (One-way ANOVA w/Bonferroni post-testing). (Magnification = 200X).
Figure 7
Figure 7. Ang-2 regulates gut neutrophil infiltration in DSS colitis
The level of neutrophil invasion, measured by myeloperoxidase (MPO) activity of the colonic tissue, was significantly elevated in WT + DSS vs. WT, and was not significantly affect in Ang-2-/- /DSS vs. WT + DSS.
Figure 8
Figure 8. Ang-2-/- status affects serum albumin content in DSS colitis
A significant decrease in the serum protein content was observed in the WT + DSS (p<0.05 vs.controls). There was no significant loss of serum protein content in Ang-2-/- or. Ang-2-/-/DSS compared to control. (One-way ANOVA with Bonferroni post-testing).
See this image and copyright information in PMC

References

    1. Ando T, Jordan P, Wang Y, et al. MAdCAM-1 expression and regulation in murine colonic endothelial cells in vitro. Inflamm Bowel Dis. 2005;11:258–264. - PubMed
    1. Bao P, Kodra A, Tomic-Canic M, et al. The role of vascular endothelial growth factor in wound healing. J Surg Res. 2009;153:347–358. - PMC - PubMed
    1. Benelli R, Albini A, Noonan D. Neutrophils and angiogenesis: potential initiators of the angiogenic cascade. Chem Immunol Allergy. 2003;83:167–181. - PubMed
    1. Benelli R, Lorusso G, Albini A, et al. Cytokines and chemokines as regulators of angiogenesis in health and disease. Curr Pharm Des. 2006;12:3101–3115. - PubMed
    1. Chidlow JH, Jr, Langston W, Greer JJ, et al. Differential angiogenic regulation of experimental colitis. Am J Pathol. 2006;169:2014–2030. - PMC - PubMed

Publication types

MeSH terms

LinkOut - more resources