Table 2 Studies on the role of CGRP in visceral pain
From: Calcitonin gene-related peptide and pain: a systematic review
Study | Objectives | Reported pain as part of phenotype | Method and sample size | Source of CGRP | Results | Duration of the investigated condition | Correlation between CGRP level and pain |
|---|---|---|---|---|---|---|---|
Arellano, 2011[1] | Investigate nerve growth factor role in development of pelvic pain in patients with endometriosis | Pain from endometriosis | Peritoneal fluids from 65 patients, 54 with pain, 11 without pain. 22 controls, where 12 reported pelvic pain | Peritoneal fluid | CGRP-neurite outgrowth was seen in patients | NR | The CGRP-neurite outgrowth did not correlate with pain symptoms |
Büchler, 1992 [2] | Identify characteristics of peptidergic innervation in patients with chronic pancreatitis | Pain from chronic pancreatitis | Pancreatic tissue from 20 patients compared to 10 organ donors | Tissue biopsies (pancreatic tissue) | CGRP-immunostaining was intensified in patients | NR | NR |
Mönnikes, 2005 [3] | Assess whether functional dyspepsia (FD) patients have altered mucosal CGRP concentrations | Pain from functional dyspepsia | Gastric mucosal biopsies from 13 patients and 18 controls. Biopsies were taken during gastric distention | Tissue biopsies (gastric mucosa) | No difference in CGRP-levels between patients and controls | The gastric distention took up to 80 min | A negative correlation between CGRP concentrations and pain was observed in patients. No such correlation was found in controls |
Tokushige, 2006 [4] | Determine the nerve fibers in patients with peritoneal endometriosis | Pain from endometriosis | Peritoneal endometriotic tissue from 40 patients and 36 healthy controls. Also 9 specimens from endosalpingiosis lesions were prepared | Tissue biopsies (endometriotic tissue) | Increase of CGRP-nerve fibers in patients, compared to controls and endosalpingiosis lesions | NR | NR |
Tokushige, 2007 [5] | Investigate types of nerve fibers in endometrium and myometrium in women with endometriosis | Pain from endometriosis | Tissue biopsies from 10 patients and 35 controls. All tissue biopsies were taken during hysterectomy | Tissue biopsies (endometriotic tissue) | Increased nerve fiber densities compared to controls | NR | NR |
Tympanidis, 2003 [6] | Evaluate nerve fiber density and pattern in patients with vulvodynia | Pain from vulvodynia | Biopsies from the wall of the vulval vestibule from 12 patients and 8 controls | Tissue biopsies (vulval vestibule) | No difference in CGRP-immunostaining between patients and controls | NR | NR |
Währborg, 1999 [7] | Clarify potential involvement of CGRP in anginal pain and myocardial ischemia in humans | Chest pain from angina and acute myocardial infarction | Plasma from 87 patients with AMI compared to 14 patients with severe angina pectoris | Blood (plasma) | No difference in CGRP-levels between patients with AMI and angina pectoris | At least 15 min | No correlation between CGRP-levels and pain |
Yoshida, 2013 [8] | Estimate expression of CGRP in esophageal mucosa in nonerosive reflux disease (NERD) patients | Pain due to NERD | Biopsies from 24 patients, compared to 24 controls | Tissue biopsies (esophageal mucosa) | No difference in CGRP-levels between patients and controls | NR | NR |