VIP (Pulmonary Expanded)
Vasoactive intestinal peptide, a bronchodilator and anti-inflammatory neuropeptide in the lung, investigated in sarcoidosis and ARDS.
Overview
VIP (vasoactive intestinal peptide) is a 28-amino-acid neuropeptide with pronounced effects in the lung, where it acts as a bronchodilator, pulmonary vasodilator, and anti-inflammatory mediator. Because pulmonary VIP and receptor levels are altered in inflammatory lung disease, VIP (as the pharmaceutical preparation aviptadil) has been investigated for sarcoidosis, asthma, pulmonary arterial hypertension, and acute respiratory distress syndrome (ARDS).
Mechanism
VIP signals through the VPAC1 and VPAC2 receptors expressed on airway smooth muscle, pulmonary vascular endothelium, and immune cells. Receptor activation raises cAMP, relaxing airway and vascular smooth muscle, and dampens inflammatory cytokine release, which is the rationale for studying VIP in lung injury and inflammation.
Dosing
Investigational use has involved inhaled or intravenous administration depending on the condition and trial. There is no approved VIP product for respiratory disease, and protocols are trial-specific.
- Inhaled delivery has been explored for airway and interstitial disease
- Intravenous infusion was used in investigational ARDS programs
- Dosing is not standardized outside clinical trials
Expected Effects
- Bronchodilation and reduced airway hyperresponsiveness in challenge studies
- Pulmonary vasodilation in models and early studies of pulmonary hypertension
- Anti-inflammatory cytokine modulation in lung-injury models
- Investigational ARDS trials reported mixed but hypothesis-generating results
Side Effects & Tolerability
VIP is generally well tolerated. Inhaled use can cause mild cough or throat irritation, and systemic administration may transiently lower blood pressure. Evidence quality varies by condition, and no respiratory indication is currently approved.
Storage
Lyophilized peptide should be stored cold and desiccated, protected from light and moisture. Reconstituted solutions are typically aliquoted and refrigerated or frozen, avoiding repeated freeze-thaw cycles.