Some patients with
colonic diverticula suffer recurrent
abdominal pain and exhibit visceral
hypersensitivity, though the mechanism is unclear. Prior
diverticulitis increases the risk of being symptomatic while experimental
colitis in animals increases expression of
neuropeptides within the enteric nervous system (ENS) which may mediate visceral
hypersensitivity. Our aim was to determine the expression of
neuropeptides within the ENS in
diverticulitis (study 1) and in patients with symptomatic disease (study 2). Study 1 - Nerves in colonic resection specimens with either acute
diverticulitis (AD, n = 16) or chronic
diverticulitis (CD, n = 16) were assessed for
neuropeptide expression recording % area staining with
protein gene product (PGP9.5),
substance P (SP),
neuropeptide K (NPK),
pituitary adenylate cyclase activating polypeptide (
PACAP),
vasoactive intestinal polypeptide (VIP) and
galanin. Study 2 - Seventeen symptomatic and 15 asymptomatic patients with
colonic diverticula underwent flexible sigmoidoscopy and multiple peridiverticular mucosal biopsies. Study 1- Neural tissue, as assessed by PGP staining was increased to a similar degree in circular muscle in both AD and CD. The CD specimens showed significant increases in the immunoreactivity of SP, NPK and
galanin in both mucosal and circular muscle layer compared with controls. Study 2 - Mucosal histology was normal and PGP9.5 staining was similar between groups however patients with symptomatic
diverticular disease demonstrated significantly higher levels of SP, NPK, VIP,
PACAP and
galanin within the mucosal plexus. Patients with symptomatic
diverticular disease exhibit increased
neuropeptides in mucosal biopsies which may reflect resolved prior
inflammation, as it parallels the changes seen in acute and chronic
diverticulitis.