Adrenomedullin reduces mesangial cell number and glomerular inflammation in experimental mesangioproliferative glomerulonephritis.
BACKGROUND
Adrenomedullin (ADM) is a vasodilator peptide that is abundantly expressed in the kidney. ADM has antiproliferative effects on glomerular mesangial cells (MC) in vitro. Whether or not treatment with ADM can reduce MC proliferation in vivo [i.e., in mesangioproliferative glomerulonephritis (GN)] is unknown. We tested the hypothesis that ADM substitution reduces MC proliferation in GN.


METHODS
GN in rats was induced by injection of an anti-Thy-1.1 antibody. Rats received osmotic minipumps, which continuously delivered rat ADM (500 ng/hour, N = 11), or vehicle (N = 13) from day 3 to day 6 after GN induction. Rats were sacrificed 6 days after induction of GN. On kidney sections, cells staining positive for proliferating cell nuclear antigen, mesangial cells, monocytes, and apoptotic cells were counted. Parameters of inflammation and fibrosis were measured in renal cortex and sieved glomeruli by real-time polymerase chain reaction (PCR).


RESULTS
Systolic blood pressure, diuresis, albuminuria, creatinine clearance, microaneurysm formation, and mesangial matrix expansion were not influenced by ADM infusion. However, ADM treatment significantly reduced the number of MC, showed a tendency to reduce total glomerular cell proliferation, and significantly increased apoptosis. ADM-treated GN animals showed significantly less glomerular monocyte infiltration. ADM treatment normalized transforming growth factor (TGF)-beta1 mRNA expression and reduced monocyte chemoattractant protein-1 (MCP-1), osteopontin, plasminogen activator inhibitor-1 (PAI-1), collagen I, and collagen III mRNA expression significantly.


CONCLUSIONS
Exogenous ADM infusion reduces MC number and glomerular monocyte infiltration in the state of mesangial proliferation during acute experimental mesangioproliferative GN. These findings indicate that ADM can influence the course of mesangioproliferative GN.
Plank
Christian
C
Department of Pediatrics, University Erlangen-Nuremberg, Germany. christian.plank@kinder.imed.uni-erlangen.de
Hartner
Andrea
A
Klanke
Bernd
B
Geissler
Bettina
B
Porst
Markus
M
Amann
Kerstin
K
Hilgers
Karl F
KF
Rascher
Wolfgang
W
Dötsch
Jörg
J
D053607:Adrenomedullin; D000818:Animals; D001835:Body Weight; D002452:Cell Count; D005355:Fibrosis; D005920:Glomerular Mesangium / Q000187:drug effects / Q000276:immunology / Q000473:pathology*; D015432:Glomerulonephritis, Membranoproliferative / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology*; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014556:Urine; D014665:Vasodilator Agents / Q000494:pharmacology*
D010455:Peptides; D014665:Vasodilator Agents; D053607:Adrenomedullin