Effect of Food Composition on Postprandial Insulin Secretion in Neonatal Diabetes

Study Overview
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Brief Summary
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Neonatal diabetes is diagnosed before 6 months of age and causes high blood glucose levels due to the pancreas not secreting insulin. Neonatal diabetes can be caused by a change in a DNA region called the KCNJ11 gene. KCNJ11 encodes a channel in the pancreas that acts as a switch to turn 'on' and 'off' insulin secretion. A change in KCNJ11 results in a faulty channel, which keeps insulin secretion 'switched off'. The diabetes can be treated with tablets called sulphonylureas that switch the pancreatic channel 'on', allowing it to secrete insulin in response to gut hormones called incretins. Previous research has shown that patients who switch from insulin to sulphonylureas have better blood glucose control, including fewer episodes of hypoglycaemia (glucose dropping too low), and also avoid the need for injections. It is thought that serious side effects from sulphonylureas are uncommon in KCNJ11 neonatal diabetes. Some patients report low glucose after meals and we think this may be because they make too much insulin if they eat a meal with protein but low amounts of carbohydrate. The investigators will test this by giving study participants different meals and measuring the amount of insulin, glucose and incretin hormone in the blood afterwards.

Detailed Description
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Anecdotal evidence from routine clinical care suggests that patients with sulphonylurea-treated KCNJ11 neonatal diabetes, when they eat, may experience mild hypoglycaemia if the food consumed lacks carbohydrate. It has been suggested that this may be due to regulation of insulin secretion via the incretin pathway as opposed to the classical ATP pathway. Therefore the investigators hypothesise that foods with a relatively high protein content compared to those with a relatively high carbohydrate content will result in excessive insulin secretion and relatively lower glucose values in KCNJ11 patients. This would be in contrast to healthy control subjects or subjects with SU-treated T2D where the insulin secretion will be moderated by the ambient glucose via the classical ATP pathway. The investigators will formally study this hypothesis by comparing the insulin, glucose and incretin hormone responses to a high protein meal with a high carbohydrate meal in people with KCNJ11 neonatal diabetes, people without diabetes and people with sulphonylurea-treated Type 2 Diabetes. To assess whether any effect seen is due to direct stimulation of the beta cell by the sulphonylurea itself, people with KCNJ11 neonatal diabetes will also undergo the same tests in the fasting state, having taken the sulphonylurea in the absence of any food.

Official Title
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Assessing the Effect of Food Composition on Postprandial Insulin Secretion in KCNJ11 Neonatal Diabetes (FoND Study)

Conditions
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Neonatal Diabetes

Intervention / Treatment
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* Other: High protein meal
* Other: High carbohydrate meal
* Drug: Paracetamol
* Other: Fasting state - sulphonylurea only


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥8yrs. Willing and able to provide informed consent (adults i.e. participants aged >16 years). Willing and able to provide assent and parents willing to provide informed consent (children and young people <16 years). Exclusion Criteria: Age <8yrs. Unable/unwilling to provide informed consent (adults). Unable/unwilling to provide assent (children) or parents unwilling to provide informed consent. Known liver disease or chronic renal impairment (EGFR <60ml/min).

Ages Eligible for Study
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Minimum Age: 8 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Neonatal diabetes<br>People with neonatal diabetes due to mutations in the KCNJ11 gene who are treated with sulphonylureas and not on insulin. | Other: High protein meal<br>* Breakfast with high protein / low carbohydrate content<br>Other: High carbohydrate meal<br>* Breakfast with high carbohydrate / low protein content<br>Drug: Paracetamol<br>* Standard dose of paracetamol administered with each meal to allow measurement of rate of gastric emptying.<br>* Other names: Acetaminophen;Other: Fasting state - sulphonylurea only<br>* People with diabetes take sulphonylurea medication in the absence of any food stimulus<br>|
| Active Comparator: Non-diabetic controls<br>People without diabetes. | Other: High protein meal<br>* Breakfast with high protein / low carbohydrate content<br>Other: High carbohydrate meal<br>* Breakfast with high carbohydrate / low protein content<br>Drug: Paracetamol<br>* Standard dose of paracetamol administered with each meal to allow measurement of rate of gastric emptying.<br>* Other names: Acetaminophen;|
| Active Comparator: Controls with Type 2 Diabetes<br>People with Type 2 diabetes who are treated with sulphonylurea medication. | Other: High protein meal<br>* Breakfast with high protein / low carbohydrate content<br>Other: High carbohydrate meal<br>* Breakfast with high carbohydrate / low protein content<br>Drug: Paracetamol<br>* Standard dose of paracetamol administered with each meal to allow measurement of rate of gastric emptying.<br>* Other names: Acetaminophen;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glucose levels | Glucose AUC after each meal. | 240 minutes | 
| Insulin levels | Insulin AUC after each meal. | 240 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| GLP-1 levels | GLP-1 AUC after each meal. | 240 minutes | 
| GIP levels | GIP AUC after each meal. | 240 minutes | 
| Glucagon levels | Glucagon AUC after each meal. | 240 minutes | 
| Paracetamol levels | Rate of change of paracetamol levels after each meal as marker of gastric emptying. | 240 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Insulin, Glucose, Incretin, GLP-1, Food