Interleukin-6 levels in the central nervous system are negatively correlated with fat mass in overweight/obese subjects.
Recently, we demonstrated that intracerebroventricular injection of IL-6 increases energy expenditure and decreases body fat in rodents. Therefore, IL-6 may play a role in appetite and body weight control in the central nervous system. In the present study we evaluated cerebrospinal fluid (CSF) and serum IL-6 levels in humans in relation to body fat content and to CSF and serum levels of leptin. Thirty-two healthy overweight/obese male subjects with a body mass index range of 29.3-36.0 kg/m(2) were studied. Total and sc body fat were measured by dual energy x-ray absorptiometry and computed tomography, respectively. CSF IL-6 levels were in some individuals higher than serum IL-6 levels and correlated negatively with total body weight, sc and total body fat. In contrast, CSF leptin levels were 30-60 times lower than serum leptin levels and correlated positively with serum leptin, body weight, sc and total body fat. Furthermore, there was a negative correlation between CSF IL-6 and leptin. In conclusion, CSF IL-6 differs in many ways from CSF leptin. CSF IL-6 may be locally produced rather than serum derived, and body fat-regulating regions in the central nervous system may be exposed to insufficient IL-6 levels in more severe obesity.
Stenlöf
Kaj
K
Research Center for Endocrinology and Metabolism, Department of Internal Medicine, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden.
Wernstedt
Ingrid
I
Fjällman
Ted
T
Wallenius
Ville
V
Wallenius
Kristina
K
Jansson
John-Olov
JO
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D002490:Central Nervous System / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015850:Interleukin-6 / Q000134:cerebrospinal fluid*; D020738:Leptin / Q000097:blood / Q000134:cerebrospinal fluid; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000134:cerebrospinal fluid* / Q000473:pathology; D012709:Serum Albumin / Q000378:metabolism
D015850:Interleukin-6; D020738:Leptin; D012709:Serum Albumin