The goal of this clinical trial is to learn whether a single dose of XBD173, a medicine that binds to a protein called the 18 kiloDalton Translocator Protein (TSPO), affects how the body processes glucose in healthy volunteers aged 18 to 75 years. The main questions it aims to answer are: * Does a single dose of XBD173 change fasting blood glucose levels compared with placebo? * Does a single dose of XBD173 change blood glucose levels after participants drink a glucose solution compared with placebo? Researchers will compare XBD173 with a placebo, which does not contain the active medicine, to see whether activating TSPO affects glucose metabolism in the fasting state and after a glucose drink. Participants will: * Attend a screening visit to confirm eligibility, including a medical history, physical examination and blood tests. * Attend four study visits after fasting overnight: two visits involving a glucose drink and two visits without a glucose drink. * Receive a single oral dose of XBD173 at some visits and placebo at other visits. The order will be randomised, and neither participants nor the study team conducting the assessments will know which treatment is given during each visit. * Have repeated blood samples taken through a cannula to measure glucose, insulin and other markers related to metabolism and inflammation. * Have resting energy use measured by breathing under a transparent canopy connected to a standard metabolic measurement device. * Have blood pressure, heart rate, height and weight measured. * Undergo measurement of blood vessel function using a cuff.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
QUADRUPLE
Enrollment
50
NIHR Trust Imperial Clinical Research Facility
London, United Kingdom
RECRUITINGPlasma Glucose Concentration in millimoles per litre During Oral Glucose Tolerance Test
Plasma glucose concentration in millimoles per litre will be measured from venous blood samples during acute glucose challenge visits after administration of XBD173 or placebo. Plasma glucose concentrations at each time point and/or the glucose response over time will be compared between XBD173 and placebo conditions.
Time frame: Blood samples will be collected at 60, 30, and 10 minutes before the oral glucose tolerance test; at the time of the test; and at 30, 60, 90, 120, 150, and 180 minutes after the test. The oral glucose tolerance test will be administered at 0 minutes.
Fasting Plasma Glucose Concentration in millimoles per litre After XBD173 or Placebo Administration
Fasting plasma glucose concentration in millimoles per litre will be measured from venous blood samples during fasting study visits after administration of XBD173 or placebo. Plasma glucose concentrations at each time point and/or the fasting glucose response over time will be compared between XBD173 and placebo conditions.
Time frame: Blood samples will be collected at 10 minutes before XBD173 or placebo administration, at administration, and at 30, 60, 90, 120, 150, 180, 210, and 240 minutes after administration.
Plasma Insulin Concentration in milliunits per litre During Oral Glucose Tolerance Test
Plasma insulin concentration in milliunits per litre will be measured from venous blood samples during acute glucose challenge visits after administration of XBD173 or placebo. Plasma insulin concentrations at each time point and/or the glucose response over time will be compared between XBD173 and placebo conditions.
Time frame: Blood samples will be collected at 60, 30, and 10 minutes before the oral glucose tolerance test; at the time of the test; and at 30, 60, 90, 120, 150, and 180 minutes after the test. The oral glucose tolerance test will be administered at 0 minutes.
Fasting Plasma Insulin Concentration in milliunits per litre After XBD173 or Placebo Administration
Fasting plasma insulin concentration in milliunits per litre will be measured from venous blood samples during fasting study visits after administration of XBD173 or placebo. Plasma insulin concentrations at each time point and/or the fasting glucose response over time will be compared between XBD173 and placebo conditions.
Time frame: Blood samples will be collected at 10 minutes before XBD173 or placebo administration, at administration, and at 30, 60, 90, 120, 150, 180, 210, and 240 minutes after administration.
Peripheral Endothelial Function Measured by Cuff-Based Assessment
Peripheral endothelial function will be measured using a cuff-based assessment during each study visit and compared between XBD173 and placebo conditions.
Time frame: Assessed at 10 minutes before the oral glucose tolerance test during acute glucose challenge visits, and at 10 minutes before XBD173 or placebo administration during fasting visits.
Respiratory Quotient Measured by Indirect Calorimetry (Acute Glucose Challenge)
Respiratory quotient will be measured using indirect calorimetry during acute glucose challenge visits and fasting visits after administration of XBD173 or placebo. Respiratory quotient values will be compared between XBD173 and placebo conditions.
Time frame: Indirect calorimetry will take place from the first study visit to the fourth visit. For acute glucose visits, respiratory quotient will be measured at 140, 90 and 30 minutes prior to OGTT, and 50, 170 minutes after OGTT.
Respiratory Quotient Measured by Indirect Calorimetry (Fasting Visits)
Respiratory quotient will be measured using indirect calorimetry during acute glucose challenge visits and fasting visits after administration of XBD173 or placebo. Respiratory quotient values will be compared between XBD173 and placebo conditions.
Time frame: Indirect calorimetry will take place from the first study visit to the fourth visit. For fasting visits, respiratory quotient will be measured at 30 minutes prior to XBD173/placebo and 50, 110, 170, 230 minutes after XBD173/placebo.
Adipose Tissue Composition From Subcutaneous Adipose Tissue Biopsy
Adipose tissue composition will be measured from subcutaneous adipose tissue samples collected by percutaneous biopsy during study visits after administration of XBD173 or placebo. Adipose tissue composition will be compared between XBD173 and placebo conditions.
Time frame: Adipose tissue biopsy will take place from the first study visit to the fourth visit, at 120 minutes after XBD173/placebo.
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