Investigation into the effects of inflammation on pain response

INTERVENTION: Randomization: double‐blind. Randomization created by study‐independent statistician using SAS 9.4 for Windows or newer (SAS Institute Inc., Cary, NC, USA), and in accordance with CHDR’s applicable standard operating procedures. Methodology: Per cohort, 11 of 12 subjects were assigned to the following treatment order: saline administration on study day 2 and LPS administration on study day 3. To one subject, LPS was administered on study day 2 and saline on study day 3. This way, both the investigator and subjects were blinded for treatment allocation. 1. Lipopolysaccharide (1 ng/kg in cohort 1 and either 0.5 ng/kg or 2 ng/kg in cohort 2) 2. Saline NaCl 0.9%, via intravenous administration) Pain test battery (electrical pain tasks, pressure pain task, heat pain task, cold pressor pain task) at ‐1h, 0h, 2h, 4h, 8h, 10h and 24h* (*: only on study day 3). The total duration was a maximum of 80 days. CONDITION: Hyperalgesia, pain ; Signs and Symptoms PRIMARY OUTCOME: ; 1. Electrical Stair (pre‐cold pressor): Pain Detection Threshold (PDT) (mA), Area Under the VAS pain Curve (AUC) (mA*mm), and post‐test VAS (mm) at ‐1h, 0h, 2h, 4h, 8h, 10h and 24h* (*: only on study day 3); 2. Electrical Stair (post‐cold pressor): PDT (mA), PTT (mA), AUC (mA*mm), and post‐test VAS (mm) at ‐1h, 0h, 2h, 4h, 8h, 10h and 24h* (*: only on study day 3); 3. Conditioned Pain Modulation Response (change from electrical stair pre‐ and post‐cold pressor): PDT (mA), PTT (mA), AUC (mA*mm) at ‐1h, 0h, 2h, 4h, 8h, 10h and 24h* (*: only on study day 3); 4. Pressure Pain: PDT (kPa), AUC (kPa*mm), and post‐test VAS (mm) at ‐1h, 0h, 2h, 4h, 8h, 10h and 24h* (*: only in on study day 3); 5. Cold Pressor: PDT (°C), AUC (°C*mm), and post‐test VAS (mm) at ‐1h, 0h, 2h, 4h, 8h, 10h and 24h* (*: only on study day 3); 6. Thermal pain: peripheral sensitization on primary and control area ‐ Pain Detection Threshold (PDT) (°C) at ‐1h, 0h, 2h, 4h, 8h, 10h and 24h* (*: only on study day 3); 7. Short Form McGill Pain Questionnaire (SF‐MPQ) scores after each of the above pain tests; SECONDARY OUTCOME: ; 1. Cytokines (including, but not limited to IL‐1ß, IL‐6, IL‐8, IL‐10, TNF‐a and IL‐1ra; IL‐17), measured with ELISA on study day 2 at 0h, 2h, 4h, 10h. On study day 3 at 0h, 5min, 15min, 30min, 1h, 2h, 3h, 4h, 10h and 24h; 2. LPS, CRP, LBP, PCT, sTREM‐1, presepsin; measured with electrochemiluminescence on study day 3 at 0h, 5min, 15min, 30min, 1h, 2h, 3h, 4h, 6h, 8h, 10h, 24h and at follow‐up visit; 3. Antibody glycosylation patterns measured with Nano‐LC‐ESI‐MS on study day 3 at ‐1h, 2h, 8h and at follow‐up visit; 4. Molecular inflammatory markers: Bradykinin, Kallikrein, cortisol and Prostaglandin E2, measured on study day 2 at 0h, 2h, 3h, 4h, 8h. On study day 3 at 0h, 2h, 3h, 4h, 8h, 24h; 5. Activation of complement pathways: classical, alternative and lectin route, measured with WIELISA on study day 3 at 0h, 4h; 6. Mitochondrial membrane potential (MMP); measured with flow cytometry on study day 2 at ‐1h, 3h, 6h. On study day 3 at ‐1h, 3h, 6h, 24h; 7. Neutrophil activation markers measured with ELISA on study day 2 at 0h, 3h. On study day 3 at 0h, 3h, 24h and at follow‐up visit; 8. Cytokines (including, but not limited to IL‐1ß, IL‐6, IL‐8, IL‐10, TNF‐a and IL‐1ra; IL‐17); measured with ELISA see above for timepoints; 9. LPS, CRP, LBP, PCT, sTREM‐1, presepsin: measured with ELISA see above for timepoints; INCLUSION CRITERIA: 1. Healthy male volunteers aged 18 to 55 years, inclusive. Healthy status is defined by absence of evidence of any active or chronic disease following a detailed medical and surgical history, a complete physical examination including vital signs, 12‐lead ECG, haematology, blood chemistry, and urinalysis 2. Body Mass Index (BMI) in the range of 18 to 28 kg/m2, and a minimum body weight of 50 kg 3. Be able to abstain from smoking between the screening visit and the study discharge visit 4. No history of alcohol or drug abuse 5. No history of trauma with likely damage to the spleen or surgery to spleen 6. Free from any clinically significant febrile illness 30 days preceding study day 1 7. Non‐atopic constitution, including non‐asthmatic 8. No use of any prescription drugs, including aspirin or other non‐steroid anti‐i