VIP（血管作動性腸管ペプチド）：CIRSと免疫研究における神経ペプチド
要約
- What it is: VIP is a 28-amino-acid neuropeptide belonging to the secretin/glucagon superfamily, acting through VPAC1 and VPAC2 receptors to modulate immune function, vasodilation, and neurotransmission.
- CIRS connection: VIP has been central to Dr. Ritchie Shoemaker's Chronic Inflammatory Response Syndrome (CIRS) treatment protocol, where it is used as a final-step intervention to address persistent biotoxin-related inflammation.
- Broad physiology: VIP influences virtually every organ system — from gut motility and pancreatic secretion to circadian rhythm regulation, airway smooth muscle relaxation, and immune cell modulation.
- Anti-inflammatory mechanism: VIP shifts immune responses from Th1/Th17 toward Th2/Treg profiles, inhibits macrophage activation, and reduces production of pro-inflammatory cytokines including TNF-alpha and IL-6.
- Status: Not FDA-approved as a therapeutic. Investigational. Used off-label in CIRS protocols. Aviptadil (synthetic VIP) has been investigated for ARDS/COVID-19.
For informational purposes only. This article does not constitute medical advice. Consult a qualified healthcare provider for any health-related decisions.
What Is VIP?
Vasoactive intestinal peptide (VIP) is a 28-amino-acid linear neuropeptide first isolated from porcine small intestine by Sami Said and Viktor Mutt in 1970. Despite its name suggesting a primarily gastrointestinal role, VIP is now recognized as one of the most widely distributed neuropeptides in the human body, found throughout the central and peripheral nervous systems, immune system, and multiple organ systems. It belongs to the secretin/glucagon/GHRH superfamily of peptides and shares structural homology with pituitary adenylate cyclase-activating polypeptide (PACAP).
VIP has attracted significant research interest for its potent immunomodulatory properties, particularly in the context of chronic inflammatory conditions and biotoxin-related illness. Its role in Dr. Ritchie Shoemaker's CIRS (Chronic Inflammatory Response Syndrome) protocol has brought it to the attention of functional and integrative medicine communities. For a broader overview of anti-inflammatory peptides, see our guide to anti-inflammatory peptides.
| Property | Detail |
|---|---|
| Full Name | Vasoactive Intestinal Peptide |
| Amino Acids | 28 |
| Molecular Weight | ~3,326 Da |
| Receptors | VPAC1 (widely distributed), VPAC2 (CNS, pancreas, immune cells) |
| Receptor Type | Class B GPCRs (Gs-coupled, cAMP signaling) |
| Half-Life | ~1–2 minutes (plasma); rapidly degraded by DPP-IV and NEP |
| Synthetic Version | Aviptadil |
| FDA Status | Not approved as therapeutic; aviptadil investigated for ARDS |
Mechanism of Action
VIP signals through two G-protein-coupled receptors — VPAC1 and VPAC2 — both of which couple primarily to the Gs protein, activating adenylyl cyclase and increasing intracellular cyclic AMP (cAMP). This cAMP elevation activates protein kinase A (PKA) and exchange protein directly activated by cAMP (Epac), triggering diverse downstream effects depending on cell type.
Immunomodulatory Actions
- Macrophage suppression: VIP inhibits macrophage production of TNF-alpha, IL-6, IL-12, and nitric oxide by suppressing NF-kB and activating CREB-dependent anti-inflammatory gene programs.
- Th1/Th17 suppression: VIP shifts T helper cell differentiation away from pro-inflammatory Th1 and Th17 phenotypes toward anti-inflammatory Th2 and regulatory T cell (Treg) phenotypes.
- Dendritic cell modulation: VIP promotes tolerogenic dendritic cells that preferentially induce Treg differentiation, potentially contributing to immune tolerance.
- Chemotaxis modulation: VIP influences immune cell migration patterns, reducing recruitment of inflammatory cells to tissue sites.
Physiological Actions Beyond Immunity
- Vasodilation: VIP is a potent vasodilator, particularly in the pulmonary, coronary, and cerebral vasculature, acting through endothelial nitric oxide release and direct smooth muscle relaxation.
- Bronchodilation: VIP relaxes airway smooth muscle and inhibits mucus hypersecretion, providing a natural bronchoprotective mechanism.
- Gut motility and secretion: VIP inhibits gastric acid secretion, stimulates pancreatic bicarbonate and water secretion, and modulates intestinal motility through its actions on enteric neurons.
- Circadian rhythm: VIP is essential for maintaining circadian rhythm synchronization in the suprachiasmatic nucleus (SCN) of the hypothalamus.
- Neuroprotection: VIP has demonstrated neuroprotective effects in models of Parkinson's disease, Alzheimer's disease, and cerebral ischemia.
Research and Clinical Investigation
CIRS Protocol (Shoemaker)
VIP has been integrated into the Shoemaker protocol for CIRS — a multi-system inflammatory condition attributed to biotoxin exposure (primarily from water-damaged buildings). In this protocol, VIP nasal spray is used as the final therapeutic step after other interventions (cholestyramine, correction of MARCoNS colonization, etc.) have been completed. Shoemaker's published case series and observational data report improvements in inflammatory markers (C4a, TGF-beta-1, MMP-9, VEGF), pulmonary function, and quality of life measures with VIP treatment.
However, this evidence comes primarily from uncontrolled observational studies rather than randomized controlled trials. The CIRS diagnosis itself remains controversial in mainstream medicine, and VIP's role in the treatment protocol has not been validated through the rigorous clinical trial process that would be required for regulatory approval.
ARDS and COVID-19 Research
Aviptadil, a synthetic form of VIP, was investigated in clinical trials for acute respiratory distress syndrome (ARDS), including COVID-19-related ARDS. The rationale was that VIP's pulmonary vasodilatory and anti-inflammatory effects could address the cytokine storm and pulmonary vascular dysfunction characteristic of severe ARDS. Phase 2/3 trials produced mixed results, with some endpoints showing improvement and others failing to reach statistical significance.
Autoimmune Disease Research
Preclinical research has extensively explored VIP as a therapeutic agent for autoimmune diseases, with promising results in animal models of rheumatoid arthritis, multiple sclerosis (EAE model), type 1 diabetes (NOD mice), and inflammatory bowel disease. These studies consistently demonstrate VIP's ability to shift immune responses toward tolerance and reduce tissue-specific inflammation.
Safety and Tolerability
VIP's very short plasma half-life (1–2 minutes) limits systemic effects but also creates pharmacokinetic challenges for therapeutic delivery. Intranasal administration, as used in the CIRS protocol, bypasses rapid plasma degradation and potentially allows direct access to CNS targets via the olfactory pathway. Common side effects of VIP include transient flushing, nasal congestion (intranasal), headache, and gastrointestinal symptoms. Its potent vasodilatory activity means hypotension is a theoretical risk, particularly with parenteral administration.
Long-term safety data for chronic VIP administration are limited. Theoretical concerns about sustained immune suppression (increased infection risk, impaired tumor surveillance) have been raised but not systematically evaluated in human studies.
Regulatory Status
VIP is not FDA-approved as a therapeutic agent for any indication. Aviptadil has received Investigational New Drug (IND) status and has been studied in clinical trials, but has not achieved FDA approval. VIP nasal spray is available through compounding pharmacies for off-label use, particularly in CIRS treatment protocols, but this use is not FDA-sanctioned. The compound remains investigational, and its therapeutic potential, while supported by extensive preclinical evidence, awaits validation through rigorous clinical trials.
免責事項： この記事は情報提供および教育目的のみです。医療アドバイス、診断、治療を構成するものではありません。ペプチドの使用や健康関連のプロトコルについて決定を下す前に、必ず資格のある医療専門家にご相談ください。
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