Larazotide Research Standard
Larazotide (CAS 258818-34-7) is a synthetic octapeptide supplied as dry-fill capsules at 500 mcg per capsule, 60 count, 30 mg total. It is a zonulin antagonist, and it acts on a target most research peptides do not touch: the paracellular space between epithelial cells rather than a receptor on their surface.[1]
Mechanism of Action & Research Context
The target is the zonulin pathway, which regulates intestinal tight junctions and therefore paracellular permeability.
Zonulin opens tight junctions; larazotide antagonises it. Zonulin family peptide is a potent regulator of intestinal tight junctions. Larazotide acetate is described as a zonulin antagonist that specifically increases intestinal barrier integrity — it tightens rather than loosens.[1]
The pathway is inducible by a defined trigger. Gliadin, the prolamine fraction of gluten, disassembles intercellular junctional proteins by upregulating the zonulin pathway, and that disassembly is inhibited by larazotide acetate. So the system has a clean agonist/antagonist pair for experimental use.[2]
Barrier integrity as a measurable checkpoint. In a mouse model, elevated serum zonulin accompanied a leaky intestinal barrier, dysbiosis and inflammation, and restoring barrier integrity before disease onset — including with larazotide acetate — reduced arthritis onset. Barrier function is treated there as a discrete, manipulable variable rather than a downstream consequence.[1]
A caution on the wider hypothesis. The review covering this area notes that attribution of many human diseases to increased paracellular permeability rested for decades on tenuous evidence, and that the supporting work is comparatively recent. The tight-junction mechanism is well defined; the breadth of what it explains is not.[2]
Research Applications
Primary fields of in vitro and preclinical laboratory investigation include:
Transepithelial electrical resistance and paracellular flux assays in intestinal epithelial monolayers such as Caco-2.[1]
Tight junction protein localisation by immunofluorescence.[2]
Gliadin challenge models, using the antagonist against a defined trigger.[2]
Serum zonulin quantification as a barrier-integrity readout.[1]
Gut-systemic axis studies linking barrier function to distant inflammation.[1]
Analytical Documentation
Purity and identity vary by manufacturing lot. Kimera Chems does not publish a single fixed purity figure for this item; refer to the batch-specific Certificate of Analysis (COA) issued for the lot received, which reflects third-party analytical testing for that lot.
References
- Tajik N, Frech M, Schulz O, et al. Targeting zonulin and intestinal epithelial barrier function to prevent onset of arthritis. Nat Commun. 2020;11(1):1995. doi:10.1038/s41467-020-15831-7
- Valitutti F, Fasano A. Breaking down barriers: how understanding celiac disease pathogenesis informed the development of novel treatments. Dig Dis Sci. 2019;64(7):1748–1758. doi:10.1007/s10620-019-05646-y
Storage & Handling
Store at controlled room temperature. Keep tightly closed.
Storage guidance is a house recommendation. Analytical documentation is per-lot release testing.
