Inhibitory effects of the peptide (CKPV)2 on endotoxin-induced host reactions.
BACKGROUND
alpha-Melanocyte stimulating hormone (alpha-MSH) is an endogenous peptide that has remarkable anti-inflammatory and antimicrobial effects. These activities have been traced to the C-terminal tripeptide Lys-Pro-Val (KPV). A dimer composed of two KPV sequences connected with a Cys-Cys linker, (CKPV)2, is currently under clinical investigation for antimicrobial use. The present research was designed to evaluate effects of (CKPV)(2) on endotoxin-induced host reactions in vitro and in vivo.


METHODS
Effects of (CKPV)2, KPV, and [Nle4-dPhe7]-alpha-MSH (NDP-alpha-MSH) on tumor necrosis factor alpha (TNF-alpha) production were determined: 1) in human peripheral blood mononuclear cells (PBMC) stimulated with lipopolysaccharide (LPS) in vitro, and 2) in rats injected with LPS i.v. and sacrificed at 1 h. In additional experiments, dialysis peritonitis was induced in rats by adding LPS to dialysis fluid. Net ultrafiltrate was calculated and concentrations of nitrite (NO2-) and TNF-alpha were measured in blood and peritoneal fluid at 7 h.


RESULTS
(CKPV)2 inhibited TNF-alpha production by LPS-stimulated human PBMC. This small peptide was as effective as NDP-alpha-MSH and more potent than KPV. Similar effectiveness was observed in vivo: 1 h after LPS injection, the large increase in circulating TNF-alpha was markedly reduced by (CKPV)2 treatment. In LPS-induced peritonitis, (CKPV)2 restored net ultrafiltrate to control values and significantly inhibited concentrations of TNF-alpha and NO2- both in plasma and in dialysate.


CONCLUSIONS
The remarkable capacity of (CKPV)2 to inhibit endotoxin-induced host reactions suggests that it may be useful in treatment of inflammatory disorders.
Gatti
Stefano
S
Department of Liver Transplantation, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milano, Italy.
Carlin
Andrea
A
Sordi
Andrea
A
Leonardi
Patrizia
P
Colombo
Gualtiero
G
Fassati
Luigi R
LR
Lipton
James M
JM
Catania
Anna
A
D000818:Animals; D018929:Cell Culture Techniques; D007963:Leukocytes, Mononuclear; D008070:Lipopolysaccharides / Q000494:pharmacology*; D009569:Nitric Oxide / Q000032:analysis; D010446:Peptide Fragments / Q000502:physiology; D010530:Peritoneal Dialysis; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D000521:alpha-MSH / Q000031:analogs & derivatives / Q000502:physiology*
D008070:Lipopolysaccharides; D010446:Peptide Fragments; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D000521:alpha-MSH; C027756:MSH, 4-Nle-7-Phe-alpha-