1. Assessing how the rapid removal of salt and water by haemodialysis alters regional brain activity (by measurement of the brain blood oxygen level-dependent (BOLD) signal using functional MRI) during tasting of soup of differing salt concentrations. 2. Identify differences in the brain response to salt taste pre- and post-haemodialysis between haemodialysis patients who are either able or unable to control between dialysis weight gain
HeMSA Study Phase 2 Up to 20 male, haemodialysis patient who have average %IDWG \>4% will be recruited with the target, to proceed to scanning, of 14 patients. Following consent the patients will complete questionnaires (including Salt intake questionnaire - DSQ (Gkza and Davenport, 2017), Edinburgh handedness questionnaire (Oldfield, 1971), MRI checklist) and undergo salt taste preference and threshold testing during a 1 hour session prior to dialysis. The purpose of this visit is to establish the tasteless solution and 2 soup salt concentrations to be used in the salt taste fMRI paradigm, obtain baseline data regarding estimate of salt intake and ensure MRI is safe for this patient. Patients will then attend 2 MRI scanning visits at the Hammersmith Hospital Imperial Campus, one the morning immediately before haemodialysis and one the morning after haemodialysis. Prior to the MRI session, at the Imperial College Clinical Research Facility, the patient will undergo various clinical assessments and have venous blood samples taken. The MRI will be undertaken at the Imperial College Clinical Imaging Facility using a Siemens 3T Verio scanner. During the scan subjects will taste, via a taste delivery system, aliquots of tasteless solution, sucralose, and 2 soup with different concentrations of salt. Solutions will be delivered in a block design. HeMSA Study Phase 3 3 groups (healthy controls, haemodialysis (HD) patients with %IDWG \<4%, haemodialysis patients with %IDWG \>4% - patients froms phase 2 will contribute to the latter group) Protocol will follow that for HeMSA Phase 2. Healthy controls will also have 2 study visits at a similar period apart to the HD participants.
Study Type
OBSERVATIONAL
Enrollment
90
Routine haemodialysis session
Imperial College Healthcare NHS Trust
London, United Kingdom
RECRUITINGChange in regional brain BOLD signal during tasting of soup of differing salt concentrations (vs. artificial saliva) pre dialysis session verse post dialysis session
Regional brain BOLD signal during tasting of soup of differing salt concentrations (vs. artificial saliva) ROI including insula, amygdala, ventral tegmental area, pre frontal cortex,
Time frame: 1 week (maximal time between pre and post dialysis scan)
Change in ratings of salt liking and intensity across different salt concentrations of soup
Ratings of liking, via Labelled Hedonic Scale (LHS) (-100=Most disliked sensation imaginable, 0=neural, 100=Most liked sensation imaginable), of salted soup of 2 concentrations pre dialysis session verse post dialysis session
Time frame: 1 week (maximal time between pre and post dialysis scan)
Change in ratings of sweet liking and intensity pre dialysis session verse post dialysis session
Ratings of liking and intensity, via Labelled Hedonic Scale (LHS) (-100=Most disliked sensation imaginable, 0=neural, 100=Most liked sensation imaginable), of sucralose solution
Time frame: 1 week (maximal time between pre and post dialysis scan)
Ratings of sour liking and intensity
Rating of liking and intensity, via Labelled Hedonic Scale (LHS) (-100=Most disliked sensation imaginable, 0=neural, 100=Most liked sensation imaginable) of citrate pre dialysis session verse post dialysis session
Time frame: 1 week (maximal time between pre and post dialysis scan)
Salt threshold testing
The lowest concentration of saline solution detected by taste. pre dialysis session verse post dialysis session
Time frame: 1 week (maximal time between pre and post dialysis scan)
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Arterial spin labelling
arterial spin labelling measurement of regional cerebral blood flow at rest pre dialysis session verse post dialysis session
Time frame: 1 week (maximal time between pre and post dialysis scan)
cerebral vascular reactivity pre dialysis session verse post dialysis session
BOLD signal changes during breath hold to assess BOLD signal reactivity to increased CO2 concentrations
Time frame: 1 week (maximal time between pre and post dialysis scan)