Inflammation and Brain Function - Pilot Study

University of California, San Francisco, The Swedish Society of Medicine, Swedish Heart Lung Foundation, The Swedish Research Council, Swedish Council for Working Life and Social Research, Stockholm University

In this randomized double blind cross-over study 8 healthy persons were injected with 0.8 ng/kg body weight lipopolysaccharide (LPS) /endotoxin and placebo at two different occasions. The aim was to investigate how pain sensitivity and health perception change in response to an acute immune activation.

Eight healthy participants were included in this randomized and balanced double blind cross-over study. They were injected two times, once with the active component and once with placebo. Participants were recruited by advertising and screened through questionnaires and a health examination by a physician. They were asked not to engage in strenuous physical activities, sleep regular hours and refrain from alcohol the day before the experiment. If the participants felt ill, e.g. coming down with a cold, they were instructed to call and were rescheduled for a later appointment. C-reactive protein (CRP) was assessed to exclude participants having an ongoing infection on the experimental day. Pregnancy was also an exclusion criteria and a pregnancy test was administered for all female participants on arrival. Several pain sensitivity measures were performed baseline and at peak inflammatory response 1-2 hours after injection. Subjects filled out questionnaires at baseline, 90 minutes and 4,5 hours after injection. The study and the procedures used in the study are described in detail here: https://openarchive.ki.se/xmlui/bitstream/handle/10616/44650/Thesis_Bianka_Karshikoff.pdf?sequence=8&isAllowed=y The following papers have been published using data from this study: Olsson MJ, Lundstrom JN, Kimball BA, Gordon AR, Karshikoff B, Hosseini N, Sorjonen K, Olgart Hoglund C, Solares C, Soop A, Axelsson J & Lekander M. The Scent of Disease: Human Body Odor Contains an Early Chemosensory Cue of Sickness. Psychol Sci. 2014 Jan 22. Sundelin T, Karshikoff B, Axelsson E, Hoglund CO, Lekander M, Axelsson J. Sick man walking: Perception of health status from body motion. Brain Behav Immun. 2015;48:53-6. Karshikoff B, Lekander M, Soop A, Lindstedt F, Ingvar M Kosek E, Olgart Höglund C, & Axelsson J. Modality and sex differences in pain sensitivity during human endotoxemia. Brain, Behavior, and Immunity. 2015 May;46:35-43

Endotoxin at 0.8 ng/kg of body weight administered intravenously (Escherichia Coli, Lot nr G3E0609, United States Pharmacopeia Rockville, MD)

Two questions were used to assess self-rated health 1"how do you rate your general health status" rated on a 5 grade Likert scale very good to very poor and 2"how is your health right now" rated on a 7 grade Likert scale from excellent to very poor

Both deep and cutaneous pain at threshold and suprathreshold noxious levels. Heat- and cold (cutaneous) pain sensitivity was assessed for threshold stimuli and intense noxious stimuli, as well as pressure (deep) pain thresholds and CPM (descending pain inhibition).

Inclusion Criteria: Healthy subjects Exclusion Criteria: Diagnosed physiological or psychiatric disease Needle anxiety or blood phobia Regular medication (excluding contraceptive pill) Infection in the last two weeks Pregnancy or breastfeeding Smoking Excessive alcohol use Body mass index in the range of obesity (>30 kg/m2) or underweight (<18.5 kg/m2) Invisible veins in the antecubital area of the arms