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Early increase and later decrease in VIP and substance P nerve fiber densities following abdominal radiotherapy: a
U Höckerfelt1, L Franzén, O Norrgård
1Department of Integrative Medical Biology, Section for Anatomy, Umeå University, SE-901 87 Umeå, Sweden.
International Journal of Radiation Biology
|November 29, 2002
Summary
Abdominal irradiation initially increases substance P (SP) and vasoactive intestinal peptide (VIP) nerve fibers in the colon but decreases them long-term. This change in neuropeptide innervation may affect gut function after radiotherapy.
Area of Science:
- Gastroenterology
- Neuroscience
- Oncology
Background:
- Neuropeptides substance P (SP) and vasoactive intestinal peptide (VIP) are crucial for intestinal motility and inflammation.
- These peptides are upregulated during tissue stress, such as following abdominal irradiation.
Purpose of the Study:
- To quantify mucosal and smooth muscle SP, VIP, and total innervation in the human colon.
- To assess these changes in both short-term and long-term perspectives after abdominal irradiation.
Main Methods:
- Immunohistochemistry and computerized image analysis were used on colon specimens from irradiated and non-irradiated patients.
- Plasma levels of SP and VIP were analyzed in patients undergoing radiotherapy.
Main Results:
- Short-term (4-7 days) post-irradiation showed increased overall innervation, SP, and VIP nerve fiber densities in the colon's mucosa and muscle layers.
- Long-term (5-6 weeks and years) post-irradiation revealed decreased SP and VIP nerve fiber densities.
- No significant changes in plasma SP or VIP levels were observed.
Conclusions:
- Radiotherapy initially increases SP and VIP innervation in the colon, potentially influencing inflammation and motility.
- Long-term reduction in SP and VIP neuronal supply may contribute to intestinal dysfunction after radiation therapy.
- The findings suggest a dynamic role for neuropeptides in the gut's response to abdominal irradiation.