Systemic recombinant hBD2 matched anti-TNF-α and steroids for colitis treatment across three distinct mouse models, working through CCR2+ dendritic cells.
Matches anti-TNFa naturally occurring defensin peptide matched the gold-standard IBD treatment in all three colitis models
What the researchers found
Systemically administered recombinant hBD2 showed therapeutic efficacy in three distinct colitis models: DSS-induced mucosal injury, TNBS-induced loss of mucosal tolerance, and T-cell transfer colitis. In all three models, hBD2 reduced inflammation, improved disease activity index, and prevented colitis-induced weight loss.
The effectiveness matched anti-TNF-alpha treatment and steroids, which are current standard-of-care therapies for inflammatory bowel disease.
Mechanistically, hBD2 targeted dendritic cells through the CCR2 receptor. It decreased NF-kB phosphorylation (the main inflammatory switch) and increased CREB phosphorylation in these cells, effectively reprogramming them from pro-inflammatory to anti-inflammatory. This is the first study showing in vivo efficacy of a systemically administered defensin.
Why it matters
Inflammatory bowel disease (IBD) affects millions of people, and current treatments like anti-TNF drugs have significant side effects and stop working over time. A naturally occurring defensin peptide that matches their effectiveness could represent an entirely new class of IBD therapy.
The fact that hBD2 worked across three different colitis models, each representing a different disease mechanism, suggests it could be broadly effective rather than limited to one type of IBD.
The numbers in context
Effective in 3 models (DSS, TNBS, T-cell transfer); matched anti-TNF-α and steroids; targeted DCs via CCR2; first systemic defensin in vivo
How the study worked
Researchers tested recombinant hBD2 in three mouse colitis models: DSS (chemical injury), TNBS (immune-mediated), and T-cell transfer. They also treated LPS-activated human blood cells with hBD2 to study the mechanism. Flow cytometry identified dendritic cells as the target. Signaling was analyzed through NF-kB and CREB phosphorylation, and CCR2 dependence was confirmed.
Who was studied
Mice with three types of experimental colitis; human PBMCs for mechanism
What this study cannot tell us
These were mouse models of colitis, which do not perfectly replicate human IBD. The optimal dosing, frequency, and route of administration for humans are unknown.
Long-term safety of systemic defensin administration was not assessed. As a peptide, hBD2 would likely need injection rather than oral administration.
How to read the evidence
Moderate evidence from three different animal colitis models with appropriate comparator treatments. Translating to human IBD requires clinical trials.
When this study was published
Published in 2020. hBD2 for IBD is being further investigated.
The bigger picture
IBD affects millions worldwide, and current treatments (anti-TNF, steroids) cause significant side effects and often lose efficacy. A naturally occurring defensin peptide that works as well as these drugs while potentially having a better safety profile could transform IBD treatment.
Questions still open
- What is hBD2's safety profile compared to anti-TNF and steroids?
- Could oral hBD2 work for IBD, or does it require injection?
- Would hBD2 maintain efficacy with long-term use (unlike anti-TNF drugs which lose effectiveness)?
Common questions
What is hBD2 and why test it for IBD?
Could this replace anti-TNF drugs for Crohn's disease?
Read the original research
Human β-Defensin 2 Mediated Immune Modulation as Treatment for Experimental Colitis.
Frontiers in immunology, 11, 93
Citation
Koeninger, Louis; Armbruster, Nicole S; Brinch, Karoline Sidelmann; Kjaerulf, Søren; Andersen, Birgitte; Langnau, Carolin; Autenrieth, Stella E; Schneidawind, Dominik; Stange, Eduard F; Malek, Nisar P; Nordkild, Peter; Jensen, Benjamin A H; Wehkamp, Jan. (2020). Human β-Defensin 2 Mediated Immune Modulation as Treatment for Experimental Colitis.. Frontiers in immunology, 11, 93. https://doi.org/10.3389/fimmu.2020.00093