Ignite Creation Date:
2024-10-26 @ 3:41 PM
Last Modification Date:
2024-10-26 @ 3:41 PM
Study NCT ID:
NCT06610695
Status:
ENROLLING_BY_INVITATION
Last Update Posted:
None
First Post:
2024-08-30
Brief Title:
PETCT Scans Using the Tracer 11C-Csar a Bile Acid Analog to Depict and Visualize Cholestatic Disorders in Patients with Genetic Liver Disorders and Healthy Individuals
Sponsor:
None
Organization:
None
Study Overview
Official Title:
Advanced Molecular Imaging of Cholestatic Disorders in Humans Pathophysiological Characterization
Status:
ENROLLING_BY_INVITATION
Status Verified Date:
2024-08
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
No
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
Purpose The primary goal is to study liver diseases with defects in bile excretion Investigators aim to do this using a radioactive tracer that mimics human bile and can be visualized with a PETCT scanner This will help us understand where these defects occur and how they might be treated in the future
Background Patients with liver diseases affecting bile excretion are at risk of developing cirrhosis When bile cannot be excreted normally it accumulates in the liver damaging its function It can also build up in the skin causing yellowing and itching Currently patients are monitored using blood tests that do not always reflect the severity of liver disease There are a few medications available but they have limited efficacy
Advanced PETCT scanning with the radioactive tracer 11C-Csar offers a way to investigate this 11C-Csar has been developed tested and approved for human use at Aarhus University Hospital and has been used in previous patient studies
The study aims to use this method to show how 11C-Csar moves through the liver and bile ducts in both healthy individuals and patients with a genetic liver disease Investigators aim to
Observe how defects affect the liver handling of bile acids
Determine the excretion kinetics of 11C-Csar including specific rate constants
Compare standard blood tests with 11C-Csar PETCT findings to assess how well blood tests reflect actual liver damage
Visualize potential targets for future interventions
Study Plan The scientific study involves a single examination day at the Department of Nuclear Medicine and PET Participants will arrive fasting in the morning An intravenous line will be placed in both arm veins a catheter in a wrist vessel and a hepatic vein catheter The hepatic vein catheter will be inserted by a trained liver specialist using local anesthesia and ultrasound guidance confirmed by X-ray The tracer 11C-Csar and the dye indocyanine green ICG will be administered through the IV lines ICG will be infused 90 minutes before scanning and 11C-Csar will be administered at the start of the scan Blood samples will be taken from the liver and wrist during the scan which lasts about 45 minutes After the scan the catheters will be removed and the participant can go home shortly after Approximately 250-300 ml of blood will be drawn which poses no risk to the participants The total participation time is expected to be around 4 hours Some patients may be offered a second scan if they develop new symptoms repeating the scan when liver blood tests normalize
Participants Patients with bile accumulation liver diseases will be informed of the study during visits to the Department of Hepatology and Gastroenterology AUH Healthy controls will be recruited through advertisements on webpages dedicated for the purpuse Interested individuals will receive written information
Side Effects Risks and Discomfort The risk of phlebitis and bleeding from IV insertion is minimal as these procedures are performed daily
The total radiation exposure from the PETCT scan with 11C-Csar is 25 mSv
Funding The study is researcher-initiated with no financial interests for the involved researchers
Publication of Results Both negative positive and inconclusive results will be published The study results will be submitted to peer-reviewed international journals in liver disease andor radiology and presented at national and international scientific conferences
Ethics The study will be conducted following the principles of the Helsinki Declaration II with amendments and after approval by the Regional Ethics Committee for Midtjylland While there is no immediate benefit for patients the results will enhance our understanding of liver disease with bile acid accumulation Investigators believe the risks and potential side effects are outweighed by the expected benefits
Background Patients with liver diseases affecting bile excretion are at risk of developing cirrhosis When bile cannot be excreted normally it accumulates in the liver damaging its function It can also build up in the skin causing yellowing and itching Currently patients are monitored using blood tests that do not always reflect the severity of liver disease There are a few medications available but they have limited efficacy
Advanced PETCT scanning with the radioactive tracer 11C-Csar offers a way to investigate this 11C-Csar has been developed tested and approved for human use at Aarhus University Hospital and has been used in previous patient studies
The study aims to use this method to show how 11C-Csar moves through the liver and bile ducts in both healthy individuals and patients with a genetic liver disease Investigators aim to
Observe how defects affect the liver handling of bile acids
Determine the excretion kinetics of 11C-Csar including specific rate constants
Compare standard blood tests with 11C-Csar PETCT findings to assess how well blood tests reflect actual liver damage
Visualize potential targets for future interventions
Study Plan The scientific study involves a single examination day at the Department of Nuclear Medicine and PET Participants will arrive fasting in the morning An intravenous line will be placed in both arm veins a catheter in a wrist vessel and a hepatic vein catheter The hepatic vein catheter will be inserted by a trained liver specialist using local anesthesia and ultrasound guidance confirmed by X-ray The tracer 11C-Csar and the dye indocyanine green ICG will be administered through the IV lines ICG will be infused 90 minutes before scanning and 11C-Csar will be administered at the start of the scan Blood samples will be taken from the liver and wrist during the scan which lasts about 45 minutes After the scan the catheters will be removed and the participant can go home shortly after Approximately 250-300 ml of blood will be drawn which poses no risk to the participants The total participation time is expected to be around 4 hours Some patients may be offered a second scan if they develop new symptoms repeating the scan when liver blood tests normalize
Participants Patients with bile accumulation liver diseases will be informed of the study during visits to the Department of Hepatology and Gastroenterology AUH Healthy controls will be recruited through advertisements on webpages dedicated for the purpuse Interested individuals will receive written information
Side Effects Risks and Discomfort The risk of phlebitis and bleeding from IV insertion is minimal as these procedures are performed daily
The total radiation exposure from the PETCT scan with 11C-Csar is 25 mSv
Funding The study is researcher-initiated with no financial interests for the involved researchers
Publication of Results Both negative positive and inconclusive results will be published The study results will be submitted to peer-reviewed international journals in liver disease andor radiology and presented at national and international scientific conferences
Ethics The study will be conducted following the principles of the Helsinki Declaration II with amendments and after approval by the Regional Ethics Committee for Midtjylland While there is no immediate benefit for patients the results will enhance our understanding of liver disease with bile acid accumulation Investigators believe the risks and potential side effects are outweighed by the expected benefits
Detailed Description:
Background
Cholestasis is defined as a decreased flow of bile from the liver to the duodenum either due to reduced excretion from the liver defects in the enterohepatic circulation or blockage of the biliary tree Bile acids are essential for the absorption of lipophilic compounds from the intestine 1 When bile acids accumulate in the liver it causes damage to the tissue
Patients with cholestasis typically present with jaundice and pruritus caused by the bile acids accumulating in the skin Elevated blood levels of alkaline phosphatases AP gamma-glutamyl transferase and sometimes bilirubin are observed 2 The clinical workup includes ultrasound sonography US to exclude tumoursstones and specific blood tests including autoantibodies immunoglobulins etc A thorough history of familial diseases and medicine intake is also important for workup 1 A liver biopsy can be necessary to evaluate hepatic histopathological changes in the liver Treatment depends on the specific cause The present project deals with medical causes of cholestasis as described below ie not mechanical obstruction such as cancer or gallstones
Monitoring medical cholestatic disorders relies on continuous blood measurements of AP bilirubin etc Still these tests do not necessarily convey information about the degree of cholestasis from a functional point of view
The enterohepatic circulation Intact enterohepatic circulation is important since de novo synthesis of bile acids does not play a significant role in enterohepatic circulation3 Bile acids are absorbed in the terminal ilium by the ileal bile acid transporter ASBTSLC10A2 and secreted into the portal vein which delivers the bile acids back to the liver Here the Na-taurocholate co-transporting peptide NTCP and organic anion- transporting proteins OATPs mediate bile uptake from the sinusoids to hepatocytes4 The bile salt export pump BSEP facilitates the transport from hepatocytes into bile canaliculi The multidrug resistance proteins 3 and 4 MRP3ABCC3 MRP4ABCC4 and the heteromeric organic solute transporter OSTabSLC51ASLC51B mediate backflux from hepatocytes to blood 3 All these transporters can be defective in different genetic diseases and lead to cholestasis which is the case in patients with progressive familial intrahepatic cholestasis PFIC including protein-truncating mutations in tight-junction protein 2 gene TJP2 and mutations in bile salt export pump BSEP Some of these patients will debut with drug-induced liver disease DILI or have recurrent cholestasis
The functional consequences of genetic mutations and variations affecting hepatic transporter and tight- junction proteins as the cause of cholestatic disorders have been challenging to study in vivo Some disorders progress rapidly into cirrhosis and potentially hepatocellular carcinomas whereas others do not become apparent until the partially defective transporter protein is as it can be seen in drug-induced liver injury DILI eg for substrates excreted into bile via bile salt exporting protein BSEP 5-9 Studying the hepatobiliary handling of bile acids has been challenging primarily due to the livers concealed position between the portal venous and systemic blood systems and because of the inherent difficulty in retrieving sampling materials from bile
In the present project investigators wish to generate novel insights into the functional effects of cholestasis by visualizing the handling of bile acids Visualization is achieved by using functional positron emission tomographycomputer tomography PETCT
Previous studies The Department of Hepatology ampamp Gastroenterology and the Department of Nuclear Medicine ampamp PET Centre both Aarhus University Hospital have in collaboration developed a PETCT method to study the enterohepatic circulation of bile acids This method utilizes the carbon-11 labelled conjugated bile acid tracer cholylsarcosine 11C-CSAR 3 10-12
11C-CSAR is a synthetic conjugate of N-methyl glycine sarcosine and cholic acid which was chosen due to its similarity to taurocholic acid one of the essential bile salts in humans Also this bile acid is not metabolized in the body or by bacteria in the intestines
Investigators have validated the 11C-CSAR PETCT method in patients with various cholestatic disorders and healthy controls 3 11-14 Investigators plan to expand our data pool using newer and more advanced scanners and to expand the method to patients with genetic mutationsvariations in proteins involved in biliary secretion to learn about these conditions and functional effects Examination of this patient group has not been done before
Hypothesis
The hepatobiliary secretion of 11C-Csar will be reduced in patients compared to healthy individuals
Cholestatic disorders affect different steps in hepatobiliary secretion of bile acids from blood depending on the specific diseasegenetic disorder
The functional effect of cholestatic disorders varies among patients with some patients being almost unaffected and others being severely affected
The measurements from functional11C-CSar PETCT provide a better evaluationdescriptioncharacterization of patients with cholestatic disorders than standard biochemistry
Study design The study is an investigator-initiated observational study Healthy volunteers patients who present with cholestasis and patients with known genetic disorders in the hepatobiliary system will be offered participation in a functional 11C-CSAR PETCT
Participants arrive at the department at 800 AM after an overnight fast The participants will get a hepatic vein catheter two venous catheters and an artflon Indocyanine green ICG will be administered intravenously to measure hepatic flow Ficks principle
11C-CSAR is administered intravenously at the beginning of a functional PETCT The PETCT scan takes approximately 45 minutes Blood samples will be drawn from the artflon and the hepatic vein catheter during the scan to measure the hepatic blood flow and the concentrations of 11C-CSAR
Investigators aim to include 14 patients with different cholestatic disorders including genetic disorders and eight healthy volunteers
Methods 11C-CSAR PETCT 11C-CSAR is injected intravenously in micro-doses and enters the enterohepatic circulation of endogenous bile acids 3 10-13 The tracer is injected at the beginning of a dynamic PETCT scan of the hepato-biliary system By external detection this method provides real-time measurements of the time course of tissue concentrations of 11C-CSAR in liver tissue bile ducts etc Combined with arterial blood measurements from an artflon and hepatic blood flow measurements using ICG Ficks principle specific kinetic parameters of the livers handling of conjugated bile acids are calculated by fitting a mathematical model to data These parameters include uptake from sinusoidal blood back flux to sinusoids transport from hepatocytes into biliary canaliculi and bile flow Mean transit time in hepatocyte and relative tissue concentrations are also calculated 3 10-13
The 11C-CSAR PETCT scans will be performed after an overnight 8-hour fast and the participants cannot take their regular medication before the scan The participants will be placed in a supine position in the Siemens Biograph Vision Quadra with the liver within the 106 cm field of view A low-dose CT scan is performed to visualize the anatomy 50 MBq 11C-Csar mixed in 10 ml of saline water is administered intravenously over 25 seconds at the beginning of a 45-minute functional 11C-CSAR PETCT scan During the scan blood samples from the hepatic vein catheter are collected to measure concentrations of 11C-CSAR
Tracer The 11C-CSAR tracer will be prepared at the Department of Nuclear Medicine and PET Centre Aarhus University Hospital using a 3-step radio-synthesis method 16
Preparation Patients with cholestasis are followed with blood samples in the departments Before the scan of the volunteers blood samples are taken for biochemical analysis haemoglobin leukocytes thrombocytes INR CRP alanine transferase bilirubin alkaline phosphatase creatinine eGFR albumin sodium potassium and possibly other relevant health-related parameters to rule out unknown health issues related to the liver The amount of blood is 20 ml which will be drawn at the time of inclusion at the Department of Clinical Biochemistry or by us The results of the blood samples will appear in the participants regular medical journals The blood samples are discarded immediately after analysis
Women participating in the study will be asked to take a pregnancy test on the day of the scan The test will be performed on urine The urine will be discarded afterwards
Catheters Venflons are placed percutaneously in both cubital veins by a trained technician for intravenous administrations of 11C-CSAR and ICG For blood sampling an artflon catheter will be placed percutaneously in a radial artery by a trained anesthesiologist and a catheter will be placed in the hepatic vein via the right jugular vein by a trained hepatologist
Data assessment The PET data involves 11C-CSAR concentrations in liver and bile ducts and blood concentrations of 11C-CSAR in arterial and hepatic vein blood and hepatic blood flow Investigators will calculate the kinetics of hepatobiliary excretion of 11C-CSAR from the patients with cholestasis and compare them with the healthy volunteers
Data management Source data for each participant is registered in the participants PET journal or Case Report Form CRF The CRF is established as a project in REDCap and contains information on contact information and demography sex weight height Source data on blood work will be in Labka EPJ Electronic patient journal
The PET journal contains all data considering tracer production quality control administered dose and scan data including side effects related to the scan The localization of source data is kept in the trial master file TMF The signed consent forms are kept in digital form in REDCap and a physical form is kept in a locker with the TMF Data is held in the eCRF REDCap and the PET journal
Source data on each participant includes all data regarding the production of tracer and quality control administered dose data on scan results and possible deviations and complications as well as the participants health records and laboratory results This data will be registered in each participants PET journal and CRF
All research participants will perform data management and assessment Sample sizes and statistics The number of healthy subjects n8 is based on our experience from previous PET studies including 11C-CSar studies
The patient group is expected to be very heterogeneous with individual results ranging from numbers close to healthy subjects to values significantly different from healthy subjects As there are only so many patients with genetic disorders Investigators aim to include 14 during the period to get a broad range of patients
The statistical analysis is carried out in STATA and GraphPad Prism in pseudonymized form Data is deleted or anonymized after ten years
Data will be analyzed per protocol and participants who lack data considering the primary endpoints will be excluded from the analysis It will be stated in the results if any deviations from the statistical analysis plan occur Should a participant withdraw from the study before completion a new participant will be recruited to ensure to have a complete dataset of participants
Risk side effects and precautions Monitoring during 11C-CSAR PETCT During 11C-CSAR PETCT participants will be under constant medical supervision The Department of Nuclear Medicine and PET Centre has all the necessary equipment and medication in case of acute tracer-related reactions The personnel monitoring the participants are trained in treating critical allergic responses No allergic reactions is anticipated as the tracer 11C-CSAR acts like taurocholic acid which is an endogenous bile salt in humans The ICG poses a minimal risk of allergic reactions Any reactions will be monitored closely and reacted upon
Radiation risk The amount of tracer 11C-Csar will depend on the patient weight 05 MBqkg body weight will be administered with a minimum level of 25 MBq and a maximum of 50 MBq Former studies have shown that 11C-Csar performs a radiation risk of 00062 mSvMBq15 Therefore an average person weighing 75 kg will have a radiation exposure of 023 mSv The radiation dose from the low-dose CT scan is 23 mSv The radiation exposure if a patient is scanned once is 25 mSv Few of our patients will be offered a second scan resulting in a total radiation exposure of 5 mSv
As per appendix II Use of Ionizing Radiation in Health Science Research amp34Retningslinjer om anvendelse af ioniserende stråling i sundhedsvidenskabelige forsøgamp34 this corresponds to the risk category IIb Compared to the annual background radiation which is 3 mSv the given value of 25 - 5 mSv represents a relatively small contribution
A total dose of 5 mSv can be calculated to increase lifetime cancer risk by 0025 due to participation in this study This is relative to the normal 25 lifetime cancer risk
Side effects 11C-CSAR is a synthetic conjugate of N-methyl glycine sarcosine and cholic acid which was chosen due to its similarity to taurocholic acid one of humans most essential bile salts No side effects have previously been seen or are expected
ICG is used as a routine test for measuring hepatic flow and adverse events are infrequent
Catheters The participants will have venous catheters placed in each cubital vein an artflon in the radial artery and a hepatic vein catheter via the right jugular vein Insertion of the catheters may cause a small amount of pain subcutaneous bleeding and pose a minimal risk of superficial infection These catheters are used daily in the hospital without any side effects
Blood samples During the 11C-CSAR PETCT scan blood samples from the participants will be drawn from the artflon in the radial artery and the hepatic vein catheter In total 250 - 300 ml of blood will be drawn from the participants This blood loss is of no risk for the participants and the blood will be discarded immediately after analysis
Monitoring after the trial All catheters are removed after the 11C-CSAR PETCT scan and the participants can go home 30 minutes after the scan
All participants will be encouraged to contact us if they feel discomfort or have concerns regarding the trial and the scans after participating
Information from medical records The investigator will receive pass-on information from the electronic medical records Midt-EPJ regarding patients listed on the outpatient lists and admission in the bed wards fulfilment of in- and exclusion criteria prior to obtaining informed consent and the information will be passed on to the project afterwards Before obtaining informed consent information from about 50 patients will be passed on to the investigator This information is based on records from the past five years Information from the participating patients medical charts will be collected for the project from all 14 patients after obtaining written informed consent The informed consent gives the investigator and the investigator representatives direct access to information about the study participants health status from their electronic medical patient records The data include gender age medical history current medication biopsy results pathology reports and biochemical test results The consent provides the investigators their representatives and any regulatory authority direct access to obtain information from the patients medical records including electronic records for the purpose of reviewing the study participants health status necessary for the implementation of the research project and for monitoring purposes including self-inspection quality control and monitoring which they are obligated to perform
Respect for the physical and mental integrity and the privacy of the study participants The study will be registered in the Region Midt study register All data will be treated confidentially and according to the applicable Danish legislation
When participants have signed a consent information from their health records will be collected according to 43 1 in the Danish Health Law
The data will be utilized in the scientific publication of the study findings and will undergo complete anonymization ensuring that no personally identifiable information is disclosed Information regarding the participants will be protected according to the General Data Protection Regulation GDPR the Data Protection Act and the Danish Health Law 43 will be complied with
Financial statement The involved scientists initiated the study and none of the involved partners have any economic interests in the study The project is financed by Novo Nordisk Fonden 1 million DKK part of a grant totaling 850650000 million DKK The grants are provided for a more extensive research program on liver disease and imaging modalities given to Michael Sørensen The expenses include the salary for PhD student Maja Kanstrup Jørgensen and all expenses regarding the study including but not limited to scans blood samples and compensation to the participants Regnskabsafdelingen AUH administers the amount
Reimbursement The patients will not receive reimbursement but travel expenses overnight stays at the patients hotel if necessary and documented lost wages will be covered
Healthy participants are offered 1500 DKK for participation in addition to documented travel expenses and lost wages Participants must pay taxes on the specified amount and reimbursement for the study participant will only be provided after the scheduled scanning day If the healthy participants withdraw from the study before the scheduled scan no reimbursement will be provided
Eligible patients are identified from the outpatient and admission lists of the bed wards at the Department of Hepatology and Gastroenterology Aarhus University Hospital and the Department of Internal Medicine Regional Hospital of Viborg
If the patient shows interest in the project Maja or Michael will give oral information about the project If the patient is still interested the written project information and the brochure Research Participantsamp39 Rights in a Health Science Research Projectamp34 will be handed out or sent via E-boks
When the person has read the material the primary investigator Maja will have an in-depth discussion with the participant about the nature of the study and the rights of the trial subject Participant will be informed about the right to bring an assessor the right to consider for up to 24 hours and how they can withdraw their consent at any time without reason The conversation will occur in quiet surroundings with enough time to discuss the study thoroughly The investigator will ensure that the participant understands the matter of the investigation
Written and verbally informed consent will be obtained before participation in the study can begin Information about the possibilities of complaint and possible compensation regarding unforeseen side effects is given
Healthy individuals The healthy individuals will be recruited through internet advertisements on the Facebook group Forsøgspersoner Aarhus Universitet and the webpages forsøgspersonerdk forskningnu
Interested healthy individuals will be encouraged to contact the primary investigator Maja A meeting will be arranged to give oral information on the project in the same way as mentioned in the previous section Routine blood samples will be drawn to ensure no liver disease is present
The 11C-CSAR PETCT scan is booked when a signed consent is made
Publication of the results All positive negative or inconclusive results will be published Results will be presented at Danish and international meetings and published in international peer-reviewed scientific journals with author lists according to the ICMJE recommendations
Ethical aspects of the study The tests are carried out under the principles of the Helsinki Declaration II with appendix after approval by The Committee on Health Research Ethics for Region Midt Inclusion of participants follows the ethical guidelines set out by The Ethics Committee on request upon participation obtainment of informed consent information on trial subjects rights etc
11C-CSAR PETCT has been used several times in patients and healthy individuals in the department without any adverse events As mentioned the tracer 11C-CSAR has no therapeutical effect and is quickly removed from the body
ICG is often used clinically to measure hepatic flow and adverse events are infrequent
There is no direct benefit for the participants but the results will hopefully increase our insight in patients with cholestasis Patients will not experience any delay in their regular treatment
In our opinion the risks and possible side effects are outweighed by the expected benefits
When signing the informed consent letter participants will decide if they want information on unexpected findings in the scans Should incidental results occur during the scans the participants will be informed and offered regular clinical examinations
Criteria for interruption of the study for each patient
The participant withdraws the consent
The responsible physician considers the participants health endangered by continuing the trial Criteria for interruption of the study
Unexpected severe adverse events related to the trial in more than one participant
Insurance Patienterstatningen will cover subjects if necessary Timeline Inclusion will start shortly after approval from The Committee on Health Research Ethics for Region Midt PETCT scans will be planned weekly when the patients are in the departments The project is terminated after the last scan is completed or no later than five years after the approval of the study Investigators will perform data management concurrently and finish it within the duration of the PhD project
Cholestasis is defined as a decreased flow of bile from the liver to the duodenum either due to reduced excretion from the liver defects in the enterohepatic circulation or blockage of the biliary tree Bile acids are essential for the absorption of lipophilic compounds from the intestine 1 When bile acids accumulate in the liver it causes damage to the tissue
Patients with cholestasis typically present with jaundice and pruritus caused by the bile acids accumulating in the skin Elevated blood levels of alkaline phosphatases AP gamma-glutamyl transferase and sometimes bilirubin are observed 2 The clinical workup includes ultrasound sonography US to exclude tumoursstones and specific blood tests including autoantibodies immunoglobulins etc A thorough history of familial diseases and medicine intake is also important for workup 1 A liver biopsy can be necessary to evaluate hepatic histopathological changes in the liver Treatment depends on the specific cause The present project deals with medical causes of cholestasis as described below ie not mechanical obstruction such as cancer or gallstones
Monitoring medical cholestatic disorders relies on continuous blood measurements of AP bilirubin etc Still these tests do not necessarily convey information about the degree of cholestasis from a functional point of view
The enterohepatic circulation Intact enterohepatic circulation is important since de novo synthesis of bile acids does not play a significant role in enterohepatic circulation3 Bile acids are absorbed in the terminal ilium by the ileal bile acid transporter ASBTSLC10A2 and secreted into the portal vein which delivers the bile acids back to the liver Here the Na-taurocholate co-transporting peptide NTCP and organic anion- transporting proteins OATPs mediate bile uptake from the sinusoids to hepatocytes4 The bile salt export pump BSEP facilitates the transport from hepatocytes into bile canaliculi The multidrug resistance proteins 3 and 4 MRP3ABCC3 MRP4ABCC4 and the heteromeric organic solute transporter OSTabSLC51ASLC51B mediate backflux from hepatocytes to blood 3 All these transporters can be defective in different genetic diseases and lead to cholestasis which is the case in patients with progressive familial intrahepatic cholestasis PFIC including protein-truncating mutations in tight-junction protein 2 gene TJP2 and mutations in bile salt export pump BSEP Some of these patients will debut with drug-induced liver disease DILI or have recurrent cholestasis
The functional consequences of genetic mutations and variations affecting hepatic transporter and tight- junction proteins as the cause of cholestatic disorders have been challenging to study in vivo Some disorders progress rapidly into cirrhosis and potentially hepatocellular carcinomas whereas others do not become apparent until the partially defective transporter protein is as it can be seen in drug-induced liver injury DILI eg for substrates excreted into bile via bile salt exporting protein BSEP 5-9 Studying the hepatobiliary handling of bile acids has been challenging primarily due to the livers concealed position between the portal venous and systemic blood systems and because of the inherent difficulty in retrieving sampling materials from bile
In the present project investigators wish to generate novel insights into the functional effects of cholestasis by visualizing the handling of bile acids Visualization is achieved by using functional positron emission tomographycomputer tomography PETCT
Previous studies The Department of Hepatology ampamp Gastroenterology and the Department of Nuclear Medicine ampamp PET Centre both Aarhus University Hospital have in collaboration developed a PETCT method to study the enterohepatic circulation of bile acids This method utilizes the carbon-11 labelled conjugated bile acid tracer cholylsarcosine 11C-CSAR 3 10-12
11C-CSAR is a synthetic conjugate of N-methyl glycine sarcosine and cholic acid which was chosen due to its similarity to taurocholic acid one of the essential bile salts in humans Also this bile acid is not metabolized in the body or by bacteria in the intestines
Investigators have validated the 11C-CSAR PETCT method in patients with various cholestatic disorders and healthy controls 3 11-14 Investigators plan to expand our data pool using newer and more advanced scanners and to expand the method to patients with genetic mutationsvariations in proteins involved in biliary secretion to learn about these conditions and functional effects Examination of this patient group has not been done before
Hypothesis
The hepatobiliary secretion of 11C-Csar will be reduced in patients compared to healthy individuals
Cholestatic disorders affect different steps in hepatobiliary secretion of bile acids from blood depending on the specific diseasegenetic disorder
The functional effect of cholestatic disorders varies among patients with some patients being almost unaffected and others being severely affected
The measurements from functional11C-CSar PETCT provide a better evaluationdescriptioncharacterization of patients with cholestatic disorders than standard biochemistry
Study design The study is an investigator-initiated observational study Healthy volunteers patients who present with cholestasis and patients with known genetic disorders in the hepatobiliary system will be offered participation in a functional 11C-CSAR PETCT
Participants arrive at the department at 800 AM after an overnight fast The participants will get a hepatic vein catheter two venous catheters and an artflon Indocyanine green ICG will be administered intravenously to measure hepatic flow Ficks principle
11C-CSAR is administered intravenously at the beginning of a functional PETCT The PETCT scan takes approximately 45 minutes Blood samples will be drawn from the artflon and the hepatic vein catheter during the scan to measure the hepatic blood flow and the concentrations of 11C-CSAR
Investigators aim to include 14 patients with different cholestatic disorders including genetic disorders and eight healthy volunteers
Methods 11C-CSAR PETCT 11C-CSAR is injected intravenously in micro-doses and enters the enterohepatic circulation of endogenous bile acids 3 10-13 The tracer is injected at the beginning of a dynamic PETCT scan of the hepato-biliary system By external detection this method provides real-time measurements of the time course of tissue concentrations of 11C-CSAR in liver tissue bile ducts etc Combined with arterial blood measurements from an artflon and hepatic blood flow measurements using ICG Ficks principle specific kinetic parameters of the livers handling of conjugated bile acids are calculated by fitting a mathematical model to data These parameters include uptake from sinusoidal blood back flux to sinusoids transport from hepatocytes into biliary canaliculi and bile flow Mean transit time in hepatocyte and relative tissue concentrations are also calculated 3 10-13
The 11C-CSAR PETCT scans will be performed after an overnight 8-hour fast and the participants cannot take their regular medication before the scan The participants will be placed in a supine position in the Siemens Biograph Vision Quadra with the liver within the 106 cm field of view A low-dose CT scan is performed to visualize the anatomy 50 MBq 11C-Csar mixed in 10 ml of saline water is administered intravenously over 25 seconds at the beginning of a 45-minute functional 11C-CSAR PETCT scan During the scan blood samples from the hepatic vein catheter are collected to measure concentrations of 11C-CSAR
Tracer The 11C-CSAR tracer will be prepared at the Department of Nuclear Medicine and PET Centre Aarhus University Hospital using a 3-step radio-synthesis method 16
Preparation Patients with cholestasis are followed with blood samples in the departments Before the scan of the volunteers blood samples are taken for biochemical analysis haemoglobin leukocytes thrombocytes INR CRP alanine transferase bilirubin alkaline phosphatase creatinine eGFR albumin sodium potassium and possibly other relevant health-related parameters to rule out unknown health issues related to the liver The amount of blood is 20 ml which will be drawn at the time of inclusion at the Department of Clinical Biochemistry or by us The results of the blood samples will appear in the participants regular medical journals The blood samples are discarded immediately after analysis
Women participating in the study will be asked to take a pregnancy test on the day of the scan The test will be performed on urine The urine will be discarded afterwards
Catheters Venflons are placed percutaneously in both cubital veins by a trained technician for intravenous administrations of 11C-CSAR and ICG For blood sampling an artflon catheter will be placed percutaneously in a radial artery by a trained anesthesiologist and a catheter will be placed in the hepatic vein via the right jugular vein by a trained hepatologist
Data assessment The PET data involves 11C-CSAR concentrations in liver and bile ducts and blood concentrations of 11C-CSAR in arterial and hepatic vein blood and hepatic blood flow Investigators will calculate the kinetics of hepatobiliary excretion of 11C-CSAR from the patients with cholestasis and compare them with the healthy volunteers
Data management Source data for each participant is registered in the participants PET journal or Case Report Form CRF The CRF is established as a project in REDCap and contains information on contact information and demography sex weight height Source data on blood work will be in Labka EPJ Electronic patient journal
The PET journal contains all data considering tracer production quality control administered dose and scan data including side effects related to the scan The localization of source data is kept in the trial master file TMF The signed consent forms are kept in digital form in REDCap and a physical form is kept in a locker with the TMF Data is held in the eCRF REDCap and the PET journal
Source data on each participant includes all data regarding the production of tracer and quality control administered dose data on scan results and possible deviations and complications as well as the participants health records and laboratory results This data will be registered in each participants PET journal and CRF
All research participants will perform data management and assessment Sample sizes and statistics The number of healthy subjects n8 is based on our experience from previous PET studies including 11C-CSar studies
The patient group is expected to be very heterogeneous with individual results ranging from numbers close to healthy subjects to values significantly different from healthy subjects As there are only so many patients with genetic disorders Investigators aim to include 14 during the period to get a broad range of patients
The statistical analysis is carried out in STATA and GraphPad Prism in pseudonymized form Data is deleted or anonymized after ten years
Data will be analyzed per protocol and participants who lack data considering the primary endpoints will be excluded from the analysis It will be stated in the results if any deviations from the statistical analysis plan occur Should a participant withdraw from the study before completion a new participant will be recruited to ensure to have a complete dataset of participants
Risk side effects and precautions Monitoring during 11C-CSAR PETCT During 11C-CSAR PETCT participants will be under constant medical supervision The Department of Nuclear Medicine and PET Centre has all the necessary equipment and medication in case of acute tracer-related reactions The personnel monitoring the participants are trained in treating critical allergic responses No allergic reactions is anticipated as the tracer 11C-CSAR acts like taurocholic acid which is an endogenous bile salt in humans The ICG poses a minimal risk of allergic reactions Any reactions will be monitored closely and reacted upon
Radiation risk The amount of tracer 11C-Csar will depend on the patient weight 05 MBqkg body weight will be administered with a minimum level of 25 MBq and a maximum of 50 MBq Former studies have shown that 11C-Csar performs a radiation risk of 00062 mSvMBq15 Therefore an average person weighing 75 kg will have a radiation exposure of 023 mSv The radiation dose from the low-dose CT scan is 23 mSv The radiation exposure if a patient is scanned once is 25 mSv Few of our patients will be offered a second scan resulting in a total radiation exposure of 5 mSv
As per appendix II Use of Ionizing Radiation in Health Science Research amp34Retningslinjer om anvendelse af ioniserende stråling i sundhedsvidenskabelige forsøgamp34 this corresponds to the risk category IIb Compared to the annual background radiation which is 3 mSv the given value of 25 - 5 mSv represents a relatively small contribution
A total dose of 5 mSv can be calculated to increase lifetime cancer risk by 0025 due to participation in this study This is relative to the normal 25 lifetime cancer risk
Side effects 11C-CSAR is a synthetic conjugate of N-methyl glycine sarcosine and cholic acid which was chosen due to its similarity to taurocholic acid one of humans most essential bile salts No side effects have previously been seen or are expected
ICG is used as a routine test for measuring hepatic flow and adverse events are infrequent
Catheters The participants will have venous catheters placed in each cubital vein an artflon in the radial artery and a hepatic vein catheter via the right jugular vein Insertion of the catheters may cause a small amount of pain subcutaneous bleeding and pose a minimal risk of superficial infection These catheters are used daily in the hospital without any side effects
Blood samples During the 11C-CSAR PETCT scan blood samples from the participants will be drawn from the artflon in the radial artery and the hepatic vein catheter In total 250 - 300 ml of blood will be drawn from the participants This blood loss is of no risk for the participants and the blood will be discarded immediately after analysis
Monitoring after the trial All catheters are removed after the 11C-CSAR PETCT scan and the participants can go home 30 minutes after the scan
All participants will be encouraged to contact us if they feel discomfort or have concerns regarding the trial and the scans after participating
Information from medical records The investigator will receive pass-on information from the electronic medical records Midt-EPJ regarding patients listed on the outpatient lists and admission in the bed wards fulfilment of in- and exclusion criteria prior to obtaining informed consent and the information will be passed on to the project afterwards Before obtaining informed consent information from about 50 patients will be passed on to the investigator This information is based on records from the past five years Information from the participating patients medical charts will be collected for the project from all 14 patients after obtaining written informed consent The informed consent gives the investigator and the investigator representatives direct access to information about the study participants health status from their electronic medical patient records The data include gender age medical history current medication biopsy results pathology reports and biochemical test results The consent provides the investigators their representatives and any regulatory authority direct access to obtain information from the patients medical records including electronic records for the purpose of reviewing the study participants health status necessary for the implementation of the research project and for monitoring purposes including self-inspection quality control and monitoring which they are obligated to perform
Respect for the physical and mental integrity and the privacy of the study participants The study will be registered in the Region Midt study register All data will be treated confidentially and according to the applicable Danish legislation
When participants have signed a consent information from their health records will be collected according to 43 1 in the Danish Health Law
The data will be utilized in the scientific publication of the study findings and will undergo complete anonymization ensuring that no personally identifiable information is disclosed Information regarding the participants will be protected according to the General Data Protection Regulation GDPR the Data Protection Act and the Danish Health Law 43 will be complied with
Financial statement The involved scientists initiated the study and none of the involved partners have any economic interests in the study The project is financed by Novo Nordisk Fonden 1 million DKK part of a grant totaling 850650000 million DKK The grants are provided for a more extensive research program on liver disease and imaging modalities given to Michael Sørensen The expenses include the salary for PhD student Maja Kanstrup Jørgensen and all expenses regarding the study including but not limited to scans blood samples and compensation to the participants Regnskabsafdelingen AUH administers the amount
Reimbursement The patients will not receive reimbursement but travel expenses overnight stays at the patients hotel if necessary and documented lost wages will be covered
Healthy participants are offered 1500 DKK for participation in addition to documented travel expenses and lost wages Participants must pay taxes on the specified amount and reimbursement for the study participant will only be provided after the scheduled scanning day If the healthy participants withdraw from the study before the scheduled scan no reimbursement will be provided
Eligible patients are identified from the outpatient and admission lists of the bed wards at the Department of Hepatology and Gastroenterology Aarhus University Hospital and the Department of Internal Medicine Regional Hospital of Viborg
If the patient shows interest in the project Maja or Michael will give oral information about the project If the patient is still interested the written project information and the brochure Research Participantsamp39 Rights in a Health Science Research Projectamp34 will be handed out or sent via E-boks
When the person has read the material the primary investigator Maja will have an in-depth discussion with the participant about the nature of the study and the rights of the trial subject Participant will be informed about the right to bring an assessor the right to consider for up to 24 hours and how they can withdraw their consent at any time without reason The conversation will occur in quiet surroundings with enough time to discuss the study thoroughly The investigator will ensure that the participant understands the matter of the investigation
Written and verbally informed consent will be obtained before participation in the study can begin Information about the possibilities of complaint and possible compensation regarding unforeseen side effects is given
Healthy individuals The healthy individuals will be recruited through internet advertisements on the Facebook group Forsøgspersoner Aarhus Universitet and the webpages forsøgspersonerdk forskningnu
Interested healthy individuals will be encouraged to contact the primary investigator Maja A meeting will be arranged to give oral information on the project in the same way as mentioned in the previous section Routine blood samples will be drawn to ensure no liver disease is present
The 11C-CSAR PETCT scan is booked when a signed consent is made
Publication of the results All positive negative or inconclusive results will be published Results will be presented at Danish and international meetings and published in international peer-reviewed scientific journals with author lists according to the ICMJE recommendations
Ethical aspects of the study The tests are carried out under the principles of the Helsinki Declaration II with appendix after approval by The Committee on Health Research Ethics for Region Midt Inclusion of participants follows the ethical guidelines set out by The Ethics Committee on request upon participation obtainment of informed consent information on trial subjects rights etc
11C-CSAR PETCT has been used several times in patients and healthy individuals in the department without any adverse events As mentioned the tracer 11C-CSAR has no therapeutical effect and is quickly removed from the body
ICG is often used clinically to measure hepatic flow and adverse events are infrequent
There is no direct benefit for the participants but the results will hopefully increase our insight in patients with cholestasis Patients will not experience any delay in their regular treatment
In our opinion the risks and possible side effects are outweighed by the expected benefits
When signing the informed consent letter participants will decide if they want information on unexpected findings in the scans Should incidental results occur during the scans the participants will be informed and offered regular clinical examinations
Criteria for interruption of the study for each patient
The participant withdraws the consent
The responsible physician considers the participants health endangered by continuing the trial Criteria for interruption of the study
Unexpected severe adverse events related to the trial in more than one participant
Insurance Patienterstatningen will cover subjects if necessary Timeline Inclusion will start shortly after approval from The Committee on Health Research Ethics for Region Midt PETCT scans will be planned weekly when the patients are in the departments The project is terminated after the last scan is completed or no later than five years after the approval of the study Investigators will perform data management concurrently and finish it within the duration of the PhD project
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None