The expression of renin-angiotensin system components in the human gastric mucosa.
BACKGROUND
The aim of the present study was to map the distribution of representative protein components of the renin-angiotensin system (RAS) in the human gastric mucosa.


METHODS
Biopsies from the antral and corporal mucosa of healthy Helicobacter pylori negative and positive volunteers were assessed by histology, Western blot and immunohistochemistry for angiotensin II subtype 1 and 2 receptors (AT1R, AT2R) and other RAS components (angiotensinogen, renin, angiotensin converting enzyme, and neprilysin). Mucosal levels of myeloperoxidase (MPO) served as a protein marker of neutrophil infiltration.


RESULTS
AT1R and AT2R were located in a variety of cells in the human gastric mucosa, including AT1R on a subpopulation of endocrine cells in the antral mucosa. Angiotensinogen and renin were expressed by resident mesenchymal cells in lamina propria. All investigated RAS components were found in vascular endothelial cells. The AT1R protein expression was 3-4 times higher in the gastric mucosa of H. pylori positive subjects compared to the gastric mucosa of H. pylori negative subjects (p < 0.05). Gastric mucosal AT1R protein expression correlated positively with neutrophil infiltration (r = 0.7, p < 0.05).


CONCLUSIONS
Protein components of RAS are present in the human gastric mucosa. The results suggest an angiotensin II mediated impact on mucosal epithelial functions, antral endocrine properties, microvascular permeability, and gastric inflammation.
Hallersund
Peter
P
Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden. peter.hallersund@gastro.gu.se
Elfvin
Anders
A
Helander
Herbert F
HF
Fändriks
Lars
L
D000328:Adult; D000368:Aged; D000808:Angiotensinogen / Q000378:metabolism; D005260:Female; D005753:Gastric Mucosa / Q000201:enzymology / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D016480:Helicobacter pylori / Q000502:physiology; D006801:Humans; D007249:Inflammation / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015260:Neprilysin / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000378:metabolism; D012083:Renin / Q000378:metabolism; D012084:Renin-Angiotensin System; D055815:Young Adult
D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D000808:Angiotensinogen; D007703:Peptidyl-Dipeptidase A; D012083:Renin; D015260:Neprilysin