Leptin and its receptor in normal human gastric mucosa and in Helicobacter pylori-associated gastritis.
BACKGROUND
Leptin, a newly discovered weight-reducing hormone, is mainly produced in fat cells. Recently, this hormone has been reported to be produced in rat gastric mucosa cells. In the present study we analyzed the localization and expression of leptin and its receptors in normal human gastric mucosa and in patients with Helicobacter pylori-associated gastritis.


METHODS
Plasma leptin levels and gastric mucosa leptin content were determined in 39 patients with dyspepsia. Cellular localization of leptin and of the signaling receptor (Ob-RL) were assessed by immunohistochemistry. Reverse transcriptase polymerase chain reaction (RT-PCR) for leptin receptor isoforms was performed on gastric epithelial cells isolated by laser-capture-microdissection.


RESULTS
Leptin content of the corpus gastric mucosa in H. pylori-positive patients was significantly increased (4.6+/-1.2. n = 15) as compared with the H. pylori-negative group (27.5+/-0.5 pg/mg, n = 24, P = 0.006). The presence of leptin immunoreactivity was shown in the lower half of corpus epithelial glands. By RT-PCR no leptin mRNA was detectable in human gastric tissue. In contrast, expression of both Ob-R(L) and the leptin receptor isoforms could be detected in gastric epithelial cells. Leptin receptor protein was detected throughout the mucosa.


CONCLUSIONS
Leptin itself is stored and secreted but not produced in human gastric mucosa. The functional receptor and all isoforms are present in human gastric mucosa. H. pylori-associated gastritis leads to significant increases in local leptin concentration in the gastric corpus.
Breidert
M
M
Medical Dept. I, University Hospital Carl Gustav Carus, Technical University, Dresden, Germany.
Miehlke
S
S
Glasow
A
A
Orban
Z
Z
Stolte
M
M
Ehninger
G
G
Bayerdörffer
E
E
Nettesheim
O
O
Halm
U
U
Haidan
A
A
Bornstein
S R
SR
D000704:Analysis of Variance; D001706:Biopsy; D002352:Carrier Proteins / Q000378:metabolism; D016099:Endoscopy, Gastrointestinal; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism* / Q000473:pathology; D005756:Gastritis / Q000378:metabolism* / Q000382:microbiology* / Q000473:pathology; D016481:Helicobacter Infections / Q000378:metabolism* / Q000473:pathology; D016480:Helicobacter pylori; D006801:Humans; D007150:Immunohistochemistry; D020738:Leptin / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012313:RNA / Q000302:isolation & purification; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D020133:Reverse Transcriptase Polymerase Chain Reaction
D002352:Carrier Proteins; C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D012313:RNA