None listed
Conditions
Brief summary
This study is designed to evaluate the effects of the artificial sweetener, sucralose, compared to glucose and saline (control), on blood pressure, heart rate and superior mesenteric artery flow following intraduodenal infusion, in healthy older subjects. On three separate days, separated by at least 5 days, subjects will receive an ID infusion of either (1) 25 %w/v glucose at a rate of 3 kcal/min, (2) 4 mM sucralose in 0.9 %w/v saline, or (3) 0.9 %w/v saline all in a volume of 300 mL over 60 minutes (i.e. 5mL/min from t = 0 – 60 min). Saline (0.9%w/v) will be infused at a rate of 5mL/min for a further 60min (i.e. t = 60 – 120min). Measurements of blood pressure (BP), heart rate (HR) and superior mesenteric artery (SMA) blood flow by Doppler ultrasonography, cardiac output (CO), stroke volume (SV), blood glucose, serum insulin, plasma glucagon-like peptide 1 (GLP-1), gastric inhibitory polypeptide (GIP) and catecholamines under randomised, double-blind conditions. The primary hypotheses underlying the current study are that (i) compared to saline, intraduodenal infusions of glucose and sucralose will induce a larger reduction in blood pressure and increases in both heart rate and superior mesenteric artery flow and (ii) ID glucose will have a greater hypotensive response than sucralose.
Interventions
Subjects will attend on three separate occasions (after fasting from solids for 14 h and liquids for 12 h) at least five days apart.
Subjects will receive an ID (intraduodenal) infusion of each of the following on the three study days:
(1) 25 %w/v glucose at a rate of 3 kcal/min,
(2) 4 mM sucralose in 0.9 %w/v saline, or
(3) 0.9 %w/v saline
All in a volume of 300 mL over 60 minutes (i.e. 5mL/min from t = 0 – 60 min). Saline (0.9%w/v) will be infused at a rate of 5mL/min for a further 60min
Subjects will attend on three separate occasions (after fasting from solids for 14 h and liquids for 12 h) at least five days apart. Subjects will receive an ID (intraduodenal) infusion of each of the following on the three study days: (1) 25 %w/v glucose at a rate of 3 kcal/min, (2) 4 mM sucralose in 0.9 %w/v saline, or (3) 0.9 %w/v saline All in a volume of 300 mL over 60 minutes (i.e. 5mL/min from t = 0 – 60 min). Saline (0.9%w/v) will be infused at a rate of 5mL/min for a further 60min (i.e. t = 60 – 120min). On each study day, subjects will undergo measurements of blood pressure (BP), heart rate (HR) and superior mesenteric artery (SMA) blood flow by Doppler ultrasonography, cardiac output (CO), stroke volume (SV), blood glucose, serum insulin, plasma glucagon-like peptide 1 (GLP-1), gastric inhibitory polypeptide (GIP) and catecholamines under randomised, double-blind conditions. Each study will be separated by at least 5 days.
Sponsors
Professor Karen Jones
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
65 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
• Healthy subjects • Male or female subjects aged 65–80 years • Body Mass Index 19-30 kg/m²
Exclusion criteria
• History of diabetes mellitus (or fasting plasma glucose >7.0 mmol/L), severe respiratory, cardiovascular, hepatic and/or renal disease (creatinine clearance <50 mL/min), chronic alcohol abuse or epilepsy or if iron stores, or liver function tests are outside the following ranges: Alanine aminotransferase (ALT) < 55 U/L Alkaline phosphatase (ALP) 30 - 110 U/L Aspartate transaminase (AST) < 45 U/L Total bilirubin 2 - 24 µmol/L Haemoglobin 115 – 165 g/L (Females) 130 – 180 g/L (Males) Ferritin 15 – 200 µg/L (Females) 30 – 300 µg/L (Males) • Medication that influence BP or GI function • History of GI disease, including known gastroparesis, significant upper GI symptoms and gastric surgery • Smoking >10 cigarettes/day • Alcohol consumption > 20 g/day • Severe nasal septum deviation • Blood donation in the previous 12 week
Outcome results
None listed