Buy VIP: Vasoactive intestinal peptide
A peptide that influences vascular tone and at the same time targets epithelial transport processes in the airways: this dual role makes VIP a particularly interesting research peptide. Chemically, it is an endogenous neuropeptide composed of 28 amino acids. Its signals are transmitted through VPAC receptors, including VPAC1. Aviptadil is the synthetic form of the same sequence, the one used in clinical trials.
Binding to VPAC receptors sets a chain in motion: receptor activation, signal transduction and a measurable response of the target cell. This makes VIP an accessible model for studying peptidergic signaling pathways, with a special link between a neuronal signaling role and direct action on epithelial and vascular target cells.
VPAC1 and the language of the airway mucosa
In human bronchial epithelial cells, VPAC1 activation can be studied with particular clarity. When the receptor is activated by VIP, CFTR-dependent chloride secretion occurs (study in human bronchial epithelial cells). The peptide signal thus becomes a concrete transport process at the cell surface.
CFTR is a chloride channel. When chloride passes through it into the fluid lining the airways, water follows osmotically. This creates a hydrated surface that is important for the function of the airway epithelium. This coupling of receptor and ion channel is the truly interesting point: a small peptide can directly target the secretory machinery of an epithelial cell.
The finding described comes from experiments with human bronchial epithelial cells. It does not establish improved lung function in humans.
Vascular regulation: the vasoactive part
The term vasoactive refers to the effect on blood vessels. VIP can promote vasodilation by acting on smooth muscle cells of the vessel wall. In the lung, this mechanism is particularly relevant because the resistance of the pulmonary vessels helps determine blood flow through the capillary bed.
A prospective pilot study in eight patients with pulmonary hypertension investigated inhaled VIP. Immediately after inhalation, the study reported improvements in pulmonary hemodynamics; exercise measures improved in later follow-up examinations (pilot study on inhaled VIP).
The study was small and had no independent randomized placebo group. Its results are an exploratory signal of a pharmacological effect, but not established disease-modifying efficacy.
Aviptadil: mechanism meets clinical testing
The synthetic form aviptadil was tested in the TESICO trial in adults with COVID-19-associated acute hypoxemic respiratory failure. For the aviptadil comparison, 471 participants were randomized; 461 entered the modified intention-to-treat analysis.
Intravenous aviptadil did not significantly improve clinical outcomes through day 90 versus placebo (TESICO trial). The result applies to this severe COVID-19 population and the intravenous formulation. It shows that a well-supported receptor pathway and a documented clinical benefit in a specific situation can be two different things.
VIP for research: receptor biology at a glance
VIP combines a clearly defined neuropeptide with a well-described VPAC receptor pathway in human bronchial epithelial cells and a vasoactive component. This makes it an interesting model peptide for peptidergic signal transduction, epithelial secretion and vascular regulation. Anyone studying the biology of VIP encounters a peptide whose mechanisms can be traced down to the level of receptor and ion channel.
VIP is available in the shop as a variant with 10 mg per vial. Order VIP now and select it for your own research project.