Abstract
CAMP (Cathelicidin antimicrobial peptide) is synthesized and secreted by
adipocytes and involved in adipose tissue (AT) innate immune response and
host defense of subcutaneous AT against Gram positive bacteria. Data on the
regulation of CAMP in obesity and during weight loss are scarce and
reference values do not exist. Serum CAMP levels (ELISA) and AT gene
expression levels (quantitative real time PCR) were investigated in two
large and longitudinal (12 months) cohorts of severely obese patients
undergoing either a low calorie diet (LCD; n=79) or bariatric
surgery (BS; n=156). The impact of metabolic factors on CAMP
expression in vitro was investigated in differentiated 3T3-L1 adipocytes.
CAMP serum levels significantly increased after BS but not during LCD.
Females had lower CAMP serum levels and lower gene expression levels in
subcutaneous AT. CAMP was positively correlated to unfavorable metabolic
factors/adipokines and negatively to favorable
factors/adipokines. CAMP gene expression was higher in subcutaneous
than in visceral AT but serum CAMP levels were not correlated to levels of
AT gene expression. While certain bile acids upregulated CAMP expression in
vitro, high glucose/insulin as well as GLP-1 had an inhibitory
effect. There exist gender-specific and AT compartment-specific effects on
the regulation of CAMP gene expression. Weight loss induced by BS (but not
by LCD) upregulated CAMP serum levels suggesting the involvement of weight
loss-independent mechanisms in CAMP regulation such as bile acids, incretins
and metabolic factors. CAMP might represent an adipokine at the interface
between metabolism and innate immune response.
Key words
Cathelicidin antimicrobial peptide - diet - bariatric surgery - adipose tissue - adipocyte
