Post-gastrectomy osteopenia in the rat: bone structure is preserved by retaining 10%-30% of the oxyntic gland area.
BACKGROUND
The acid-producing part of the rat stomach (fundus) is rich in endocrine cells, i.e. ECL cells and A-like cells. The ECL cells operate under gastrin control and manufacture histamine, the chromogranin-derived peptide pancreastatin and an unidentified peptide hormone. The A-like cells produce ghrelin, a newly discovered growth hormone-releasing hormone. Surgical removal of the entire glandular stomach (gastrectomy, Gx) or the acid-producing part (fundectomy, Fx) causes osteopenia, which is striking in the calvaria. We speculate that the osteopenia develops after surgical removal of the fundus, because the fundus hosts agents that preserve bone. This study examines how much of the fundus is needed to preserve normal skull bone.


METHODS
Increasing portions of the fundus were resected surgically. The serum gastrin, ghrelin and pancreastatin concentrations were measured. The rats were killed after 10 weeks and the calvariae were subjected to transillumination analysis and quantitative histomorphometry.


RESULTS
Fx elevated serum gastrin in proportion to the amount of fundus resected, i.e., the more fundus that was resected, the higher the serum gastrin concentration. Serum ghrelin and pancreastatin concentrations were reduced proportionally to the amount of fundus resected. In rats subjected to 90% or 100% Fx, the calvariae displayed the anticipated pattern of bone loss. No bone loss was seen when 70% or less of the fundus was resected.


CONCLUSIONS
The results of the present study indicate that 10%-30% of the fundic mucosa is needed to preserve bone. The Gx/Fx-evoked osteopenia may be explained by hormonal deficiency caused by surgically eliminating or diminishing one of the endocrine cell populations in the fundic mucosa.
Lehto-Axtelius
D
D
Dept. of Radiology, Centre for Oral Health Sciences, Malmö University, Sweden.
Chen
D
D
Surve
V V
VV
Håkanson
R
R
D000818:Animals; D001851:Bone Diseases, Metabolic / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D053379:Chromogranin A; D005743:Gastrectomy / Q000009:adverse effects* / Q000379:methods; D005748:Gastric Fundus / Q000378:metabolism / Q000601:surgery*; D005753:Gastric Mucosa / Q000473:pathology; D005755:Gastrins / Q000097:blood; D054439:Ghrelin; D013006:Growth Hormone / Q000097:blood; D008297:Male; D010187:Pancreatic Hormones / Q000097:blood; D010295:Parietal Cells, Gastric / Q000378:metabolism; D036361:Peptide Hormones; D010455:Peptides / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000378:metabolism / Q000473:pathology
D053379:Chromogranin A; D005755:Gastrins; D054439:Ghrelin; D010187:Pancreatic Hormones; D036361:Peptide Hormones; D010455:Peptides; C050836:pancreastatin; D013006:Growth Hormone