Effects of somatostatin and octreotide on cytokine and chemokine production by lipopolysaccharide-activated peripheral blood mononuclear cells.
BACKGROUND
Somatostatin plays an important role in the communication between the nervous, endocrine, and immune systems. Although somatostatin or its analogues have been shown to modulate a number of immune functions, their immunomodulatory effects are not uniform and are strongly dependent on the underlying cell system.


OBJECTIVE
The aim of our study was to analyze the immunomodulatory effects of somatostatin and its analogue octreotide on peripheral blood mononuclear cells (PBMC) in vitro. MATERIALS/SUBJECTS:We used lipopolysaccharide-activated cells from normal glucose tolerant (NGT) subjects and from Type 2 diabetes mellitus (T2DM) patients as T2DM is associated with chronic, low-grade inflammation, and measured immune mediator release with multiplex bead-based assays.


RESULTS
Our data showed no statistically significant effects on the secretion of the cytokines interleukin (IL)-1beta, IL-6, IL-10, IL-12, interferon-gamma and tumor necrosis factor-alpha as well as the chemokines IL-8 and monocyte chemoattractant protein (MCP)-1, either on PBMC from T2DM patients or on those from NGT controls. However, a trend towards a dose-dependent biphasic effect was observed for IL- 6, IL-10 and MCP-1 with reduced immune mediator levels at low and increased/unaltered levels at higher somatostatin or octreotide concentrations. These observations could not be explained by interference with cell viability or proliferation.


CONCLUSIONS
We could not confirm immunomodulatory properties of somatostatin and octreotide on PBMC. Further analyses are necessary to explain the interaction between neuropeptides and the immune system.
Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center at Heinrich Heine University Düsseldorf, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany.
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F
ter Veld
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Rose
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R
Mussmann
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Martin
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Herder
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K
Kempf
D000328:Adult; D000368:Aged; D018932:Chemokine CCL2 / Q000096:biosynthesis; D018925:Chemokines / Q000096:biosynthesis*; D016207:Cytokines / Q000096:biosynthesis*; D003924:Diabetes Mellitus, Type 2 / Q000276:immunology; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D053583:Interleukin-1beta / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008875:Middle Aged; D015282:Octreotide / Q000494:pharmacology*; D013004:Somatostatin / Q000494:pharmacology*
D018932:Chemokine CCL2; D018925:Chemokines; D016207:Cytokines; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides; D016753:Interleukin-10; D018664:Interleukin-12; D013004:Somatostatin; D015282:Octreotide