Investigating the Incretin Effect in Cystic Fibrosis

NCT ID: NCT01975259

Last Updated: 2015-09-02

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

50 participants

Study Classification

OBSERVATIONAL

Study Start Date

2013-12-31

Study Completion Date

2015-07-31

Brief Summary

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Most Cystic fibrosis (CF) patients now commonly live well into adulthood, this means they are progressively accumulating damage to the insulin-secreting cells inside their pancreas. This explains why most adult patients have some degree of abnormal sugar regulation \& rates of diabetes rise significantly with age. CF related diabetes is categorically different from other types of diabetes \& its development is serious as it heralds a faster decline in lung function \& a reduced life expectancy.

The hallmark of abnormal sugar handling in CF is high glucose levels after meals as the damaged pancreas responds abnormally slowly. Over 70% of the initial response of a healthy pancreas is induced, not by glucose alone, but by hormones released from the bowel known as incretins. We want to establish whether incretins are important in blood sugar handling in CF as specific drugs that enhance their effect are now available.

The study hypothesis is that the incretin system will function normally in patients with Cystic Fibrosis. To show this we will measure how much insulin secretion is dependant on incretin hormones in CF patients by comparing levels after a sugary drink test and then an intravenous glucose drip test (run at a rate that mimics the blood sugar levels obtained during the first test to make it a fair comparison ) - as incretins will only be produced in the first test when the sugar passes through the bowel any extra insulin produced will be due to these hormones. To detect resistance to the incretin hormones we will separately measure responses to direct infusions of the hormones themselves. We will explore which components of meals cause incretin hormone release from the bowel wall by measuring blood levels after different types of meals are consumed. Finally we will measure levels of the enzyme that breaks down the incretin hormones (DPP-4) to know if they are deactivated more quickly in people with CF. By describing the incretin system in CF we will considerably improve our understanding of this important condition as well as potentially highlighting new ways to treat it.

Detailed Description

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Conditions

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Cystic Fibrosis

Study Design

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Observational Model Type

CASE_CONTROL

Study Time Perspective

PROSPECTIVE

Study Groups

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Cystic Fibrosis

Adult patients with confirmed cystic fibrosis who are clinically stable. Interventions:

Oral Glucose Tolerance test (75g 2-hour) Modified Oral Glucose Tolerance Test (50g 4-hours) Matched isoglycemic clamp Hyperglycemic clamp with concurrent GLP-1 infusion Hyperglycemic Clamp with concurrent GIP infusion Hyperglycemic clamp with placebo infusion Liquid Meal Test (Carbohydrate-rich) Continuous Glucose Monitoring

Oral Glucose Tolerance test (75g 2-hour)

Intervention Type DRUG

A standard 2-hour oral glucose tolerance test where fasted patients (10hours overnight) consume a 75g glucose solution \& have glucose levels recorded up to every 30 mins for 2hours

Modified Oral Glucose Tolerance Test (50g 4-hours)

Intervention Type DRUG

A 4-hour version of the oral glucose tolerance test where fasted patients (10hours overnight) consume a 50g of glucose solution \& have glucose levels recorded up to every 5mins as well pancreatic and incretin responses at 10 fixed time points.

Matched isoglycemic clamp

Intervention Type DRUG

A glucose drip will be infused at a variable rate that recreates the individual subjects blood glucose values obtained during their 4-hour modified oral glucose tolerance test. This test will therefore last 4-hours and again subjects will be fasted (10hours overnight) at the time of the test. The same blood tests will be performed at the same time points as the modified glucose tolerance test

Hyperglycemic clamp with concurrent GLP-1 infusion

Intervention Type DRUG

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp). After 60mins an infusion of GLP-1 will be commenced at a rate of 0.25pmol/kg/min for 60mins and then continued at a rate of 1.2pmol/kg/min for a further 60mins. Subjects will be blinded to what infusion they are receiving.

Hyperglycemic Clamp with concurrent GIP infusion

Intervention Type DRUG

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp). After 60mins an infusion of GIP will be commenced at a rate of 1pmol/kg/min for 60mins and then continued at a rate of 4pmol/kg/min for a further 60mins. Subjects will be blinded to what infusion they are receiving.

Hyperglycemic clamp with placebo infusion

Intervention Type DRUG

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp).

After 60mins an infusion of normal saline will be commenced as a placebo infusion. It will be infused at a rate so that the total volume of fluid is similar to that infused during the other two hyperglycemic clamp interventions. Subjects will be blinded to what infusion they are receiving.

Liquid Meal Test (Carbohydrate-rich)

Intervention Type OTHER

A standardised liquid meal (carbohydrate-rich) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Liquid Meal Test (Fat-rich)

Intervention Type OTHER

A standardised liquid meal (fat-rich) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Liquid Meal Test (Mixed)

Intervention Type OTHER

A standardised liquid meal (mixed) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Continuous Glucose Monitoring

Intervention Type DEVICE

Continuous glucose monitoring entails wearing a small portable device, usually on the upper arm, for a period of three days. The device uses a small plastic tube to record the glucose level from interstitial fluid \& every minute wirelessly transmits this information to a base unit to enable a very accurate estimate of average blood sugar control to be defined.

Controls

Adult Non-CF subjects matched for age and body mass index with normal glucose tolerance.

Oral Glucose Tolerance test (75g 2-hour) Modified Oral Glucose Tolerance Test (50g 4-hours) Matched isoglycemic clamp Hyperglycemic clamp with concurrent GLP-1 infusion Hyperglycemic Clamp with concurrent GIP infusion Hyperglycemic clamp with placebo infusion Liquid Meal Test (Carbohydrate-rich)

Oral Glucose Tolerance test (75g 2-hour)

Intervention Type DRUG

A standard 2-hour oral glucose tolerance test where fasted patients (10hours overnight) consume a 75g glucose solution \& have glucose levels recorded up to every 30 mins for 2hours

Modified Oral Glucose Tolerance Test (50g 4-hours)

Intervention Type DRUG

A 4-hour version of the oral glucose tolerance test where fasted patients (10hours overnight) consume a 50g of glucose solution \& have glucose levels recorded up to every 5mins as well pancreatic and incretin responses at 10 fixed time points.

Matched isoglycemic clamp

Intervention Type DRUG

A glucose drip will be infused at a variable rate that recreates the individual subjects blood glucose values obtained during their 4-hour modified oral glucose tolerance test. This test will therefore last 4-hours and again subjects will be fasted (10hours overnight) at the time of the test. The same blood tests will be performed at the same time points as the modified glucose tolerance test

Hyperglycemic clamp with concurrent GLP-1 infusion

Intervention Type DRUG

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp). After 60mins an infusion of GLP-1 will be commenced at a rate of 0.25pmol/kg/min for 60mins and then continued at a rate of 1.2pmol/kg/min for a further 60mins. Subjects will be blinded to what infusion they are receiving.

Hyperglycemic Clamp with concurrent GIP infusion

Intervention Type DRUG

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp). After 60mins an infusion of GIP will be commenced at a rate of 1pmol/kg/min for 60mins and then continued at a rate of 4pmol/kg/min for a further 60mins. Subjects will be blinded to what infusion they are receiving.

Hyperglycemic clamp with placebo infusion

Intervention Type DRUG

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp).

After 60mins an infusion of normal saline will be commenced as a placebo infusion. It will be infused at a rate so that the total volume of fluid is similar to that infused during the other two hyperglycemic clamp interventions. Subjects will be blinded to what infusion they are receiving.

Liquid Meal Test (Carbohydrate-rich)

Intervention Type OTHER

A standardised liquid meal (carbohydrate-rich) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Liquid Meal Test (Fat-rich)

Intervention Type OTHER

A standardised liquid meal (fat-rich) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Liquid Meal Test (Mixed)

Intervention Type OTHER

A standardised liquid meal (mixed) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Interventions

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Oral Glucose Tolerance test (75g 2-hour)

A standard 2-hour oral glucose tolerance test where fasted patients (10hours overnight) consume a 75g glucose solution \& have glucose levels recorded up to every 30 mins for 2hours

Intervention Type DRUG

Modified Oral Glucose Tolerance Test (50g 4-hours)

A 4-hour version of the oral glucose tolerance test where fasted patients (10hours overnight) consume a 50g of glucose solution \& have glucose levels recorded up to every 5mins as well pancreatic and incretin responses at 10 fixed time points.

Intervention Type DRUG

Matched isoglycemic clamp

A glucose drip will be infused at a variable rate that recreates the individual subjects blood glucose values obtained during their 4-hour modified oral glucose tolerance test. This test will therefore last 4-hours and again subjects will be fasted (10hours overnight) at the time of the test. The same blood tests will be performed at the same time points as the modified glucose tolerance test

Intervention Type DRUG

Hyperglycemic clamp with concurrent GLP-1 infusion

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp). After 60mins an infusion of GLP-1 will be commenced at a rate of 0.25pmol/kg/min for 60mins and then continued at a rate of 1.2pmol/kg/min for a further 60mins. Subjects will be blinded to what infusion they are receiving.

Intervention Type DRUG

Hyperglycemic Clamp with concurrent GIP infusion

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp). After 60mins an infusion of GIP will be commenced at a rate of 1pmol/kg/min for 60mins and then continued at a rate of 4pmol/kg/min for a further 60mins. Subjects will be blinded to what infusion they are receiving.

Intervention Type DRUG

Hyperglycemic clamp with placebo infusion

An intravenous glucose infusion will be infused at a rate that maintains blood glucose at a level of 180-216mg/dL (10-12 mmol/l) (hyperglycemic clamp).

After 60mins an infusion of normal saline will be commenced as a placebo infusion. It will be infused at a rate so that the total volume of fluid is similar to that infused during the other two hyperglycemic clamp interventions. Subjects will be blinded to what infusion they are receiving.

Intervention Type DRUG

Liquid Meal Test (Carbohydrate-rich)

A standardised liquid meal (carbohydrate-rich) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Intervention Type OTHER

Liquid Meal Test (Fat-rich)

A standardised liquid meal (fat-rich) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Intervention Type OTHER

Liquid Meal Test (Mixed)

A standardised liquid meal (mixed) containing approximately 500kcal would be administered to patients who had fasted overnight (10hrs). Over the next 4hours bloods would be sampled at 10 fixed time points to measure features of the incretin response to this type of meal.

Intervention Type OTHER

Continuous Glucose Monitoring

Continuous glucose monitoring entails wearing a small portable device, usually on the upper arm, for a period of three days. The device uses a small plastic tube to record the glucose level from interstitial fluid \& every minute wirelessly transmits this information to a base unit to enable a very accurate estimate of average blood sugar control to be defined.

Intervention Type DEVICE

Other Intervention Names

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OGTT Modified OGTT 50g OGTT isoglycemic clamp Glucagon-like peptide-1 gastric inhibitory polypeptide glucose-dependent insulinotropic peptide Hyperglycemic clamp with normal saline (0.9%) infusion CGM CGMS

Eligibility Criteria

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Inclusion Criteria

* Cystic fibrosis as diagnosed by EITHER Cystic fibrosis transmembrane conductance regulator (CFTR) mutation on genotyping OR Positive sweat test (Chloride ≥60mmol/L after pilocarpine iontophoresis) AND Clinical features in keeping with a diagnosis of Cystic Fibrosis
* Clinically stable for at least 4 weeks without inpatient or outpatient treatment for an infective exacerbation - including antibiotics (other than long-term prophylactic therapy) or steroids

Exclusion Criteria

* Active Pregnancy or \<12 months Post-partum
* Clinically unstable patients
* Patients on long-term steroids
* Patients with known gastroparesis or previous surgery to the gastrointestinal tract (including vagotomy)
* History of organ transplant or planned organ transplant awaited
* Non-CF related diabetes (e.g. Type 1 or 2 Diabetes Mellitus)
* Active malignancy
* Clinically significant derangements in haematological or biochemical indices
* Clinical symptoms of malabsorption (frequent bowel motions/passing of undigested foodstuffs or steatorrhoea)
* Known difficult venous access
* Use of bile acid sequestrants in the previous 4 weeks
Minimum Eligible Age

17 Years

Maximum Eligible Age

50 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Liverpool Heart and Chest Hospital NHS Foundation Trust

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Gareth H Jones, MBChB

Role: PRINCIPAL_INVESTIGATOR

Liverpool Heart and Chest Hospital

Locations

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Liverpool Heart and Chest Hospital

Liverpool, , United Kingdom

Site Status

Countries

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United Kingdom

References

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Nauck M, Stockmann F, Ebert R, Creutzfeldt W. Reduced incretin effect in type 2 (non-insulin-dependent) diabetes. Diabetologia. 1986 Jan;29(1):46-52. doi: 10.1007/BF02427280.

Reference Type BACKGROUND
PMID: 3514343 (View on PubMed)

Nauck MA, Heimesaat MM, Orskov C, Holst JJ, Ebert R, Creutzfeldt W. Preserved incretin activity of glucagon-like peptide 1 [7-36 amide] but not of synthetic human gastric inhibitory polypeptide in patients with type-2 diabetes mellitus. J Clin Invest. 1993 Jan;91(1):301-7. doi: 10.1172/JCI116186.

Reference Type BACKGROUND
PMID: 8423228 (View on PubMed)

Mohan K, Miller H, Dyce P, Grainger R, Hughes R, Vora J, Ledson M, Walshaw M. Mechanisms of glucose intolerance in cystic fibrosis. Diabet Med. 2009 Jun;26(6):582-8. doi: 10.1111/j.1464-5491.2009.02738.x.

Reference Type BACKGROUND
PMID: 19538232 (View on PubMed)

Milla CE, Warwick WJ, Moran A. Trends in pulmonary function in patients with cystic fibrosis correlate with the degree of glucose intolerance at baseline. Am J Respir Crit Care Med. 2000 Sep;162(3 Pt 1):891-5. doi: 10.1164/ajrccm.162.3.9904075.

Reference Type BACKGROUND
PMID: 10988101 (View on PubMed)

Hameed S, Morton JR, Jaffe A, Field PI, Belessis Y, Yoong T, Katz T, Verge CF. Early glucose abnormalities in cystic fibrosis are preceded by poor weight gain. Diabetes Care. 2010 Feb;33(2):221-6. doi: 10.2337/dc09-1492. Epub 2009 Nov 12.

Reference Type BACKGROUND
PMID: 19910502 (View on PubMed)

Dobson L, Sheldon CD, Hattersley AT. Validation of interstitial fluid continuous glucose monitoring in cystic fibrosis. Diabetes Care. 2003 Jun;26(6):1940-1. doi: 10.2337/diacare.26.6.1940-a. No abstract available.

Reference Type BACKGROUND
PMID: 12766139 (View on PubMed)

Costa M, Potvin S, Hammana I, Malet A, Berthiaume Y, Jeanneret A, Lavoie A, Levesque R, Perrier J, Poisson D, Karelis AD, Chiasson JL, Rabasa-Lhoret R. Increased glucose excursion in cystic fibrosis and its association with a worse clinical status. J Cyst Fibros. 2007 Nov 30;6(6):376-83. doi: 10.1016/j.jcf.2007.02.005. Epub 2007 Apr 3.

Reference Type BACKGROUND
PMID: 17409029 (View on PubMed)

Hillman M, Eriksson L, Mared L, Helgesson K, Landin-Olsson M. Reduced levels of active GLP-1 in patients with cystic fibrosis with and without diabetes mellitus. J Cyst Fibros. 2012 Mar;11(2):144-9. doi: 10.1016/j.jcf.2011.11.001. Epub 2011 Dec 3.

Reference Type BACKGROUND
PMID: 22138561 (View on PubMed)

Anzeneder L, Kircher F, Feghelm N, Fischer R, Seissler J. Kinetics of insulin secretion and glucose intolerance in adult patients with cystic fibrosis. Horm Metab Res. 2011 May;43(5):355-60. doi: 10.1055/s-0031-1275270. Epub 2011 Mar 29.

Reference Type BACKGROUND
PMID: 21448848 (View on PubMed)

Lanng S, Thorsteinsson B, Roder ME, Orskov C, Holst JJ, Nerup J, Koch C. Pancreas and gut hormone responses to oral glucose and intravenous glucagon in cystic fibrosis patients with normal, impaired, and diabetic glucose tolerance. Acta Endocrinol (Copenh). 1993 Mar;128(3):207-14. doi: 10.1530/acta.0.1280207.

Reference Type BACKGROUND
PMID: 8480468 (View on PubMed)

Other Identifiers

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2013-003758-26

Identifier Type: EUDRACT_NUMBER

Identifier Source: secondary_id

1004

Identifier Type: -

Identifier Source: org_study_id

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