- Email: [email protected]
Six minute bicycling test in children with mitochondrial disorders: Feasibility, reliability, validity and responsivity
Abstracts
transfer to prevent the transmission of mitochondrial disorders in humans. doi:10.1016/j.mito.2013.07.005
6 Towards harmonization of outcome measures in children with mitochondrial disorders Presenter: Saskia Koene Saskia Koenea, Merel Jansenb, Chris M. Verhaaka,c, Remco L.A. de Vruehd, Imelda J.M. de Groota,b, Jan A.M. Smeitinka a Radboud University Nijmegen Medical Centre, Nijmegen Centre for Mitochondrial Disorders, Department of Paediatrics, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands1 b Radboud University Nijmegen Medical Centre, Nijmegen Centre of Evidence Based Practice, Department of Rehabilitation, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands c Radboud University Nijmegen Medical Centre, Department of Medical Psychology, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands d Rare disease matters, Leiden, The Netherlands 1 www.ncmd.nl. Abstract: A clinical trial is only as reliable as its outcomes, therefore the careful and systematic selection of outcome measures is extremely important. Currently, the selection of outcome measures for clinical trials designed to evaluate new drugs in patients with mitochondrial disorders is inefficient and is not addressed systematically. Given that meaningful data can be obtained only from trials in which outcomes are assessed using valid instruments, one should first focus on the validation of a set of selected instruments in the target population. We aimed to systematically select robust outcome measures that are relevant to all patients. We composed a toolbox with outcome measures based on a primary search for possible instruments using an extensive search of published literature. Subsequently, we reduced this toolbox using strict criteria that were adapted from the US Food and Drug Administration. The product of our study is a toolbox with clinically relevant and psychometrically robust instruments for performing clinical research in children with mitochondrial disorders. In coming years, more experience using these outcome measures in children with various mitochondrial disease phenotypes must be obtained before reliable conclusions regarding the validity of these instruments can be drawn.
899
b
Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Geert Grooteplein 10. 6500 HB, PO Box 9101, Nijmegen, The Netherlands c Radboud University Nijmegen Medical Centre, Department of Laboratory Medicine, Geert Grooteplein 10. 6500 HB, PO Box 9101, Nijmegen, The Netherlands d Radboud University Nijmegen Medical Centre, Department of Epidemiology, Biostatistics and Health Technology Assessment, Geert Grooteplein 10. 6500 HB, PO Box 9101 Nijmegen, The Netherlands e Radboud University Nijmegen Medical Centre, Department of General Internal Medicine, Geert Grooteplein 10. 6500 HB, PO BOX 9101, Nijmegen, The Netherlands 1 www.ncmd.nl.
Abstract: The m.3243ANG nucleotide change is one of the most commonly detected mitochondrial DNA mutations. Patients harbouring this mutation display a widely variable phenotype, ranging from fullblown MELAS/MIDD syndrome with mitochondrial encephalopathy, lactic acidosis and stroke-like episodes or maternally inherited diabetes and deafness to no complaints at all. Since the maternal relatives of patients with the m.3243ANG, with a few exceptions of sporadic cases reported, carry the mutation, they are also at risk of developing clinical symptoms. Currently, the heteroplasmy percentage of the mutation is used to predict disease development of these dormant carriers, but this parameter is known to have a weak correlation with the severity of the disease. In a previous study, Fibroblast Growth Factor 21 (FGF-21) was found to be a sensitive and specific biomarker for the presence of muscle-manifesting mitochondrial disease. In this study, we investigated the value of this biomarker in indicating disease severity and disease progression of m.3243ANG carriers in a large cohort of patients with the m.3243ANG mutation and their maternal relatives. We used the Newcastle Mitochondrial Disease Scale to measure general disease severity and disease progression after one year. Results are currently under statistical analysis. Reference Suomalainen A, Elo JM, Pietilainen KH, Hakonen AH, Sevastianova K, Korpela M, et al. FGF-21 as a biomarker for muscle-manifesting mitochondrial respiratory chain deficiencies: a diagnostic study. Lancet Neurol. 2011 Sep;10(9):806-18. doi:10.1016/j.mito.2013.07.007
Reference Koene S, Jansen M, Verhaak CM, de Groot, IJM, Smeitink JAM. Towards standardization of Outcome Measures in Children with Mitochondrial Disorders. Submitted for publication to Developmental Medicine and Child Neurology. doi:10.1016/j.mito.2013.07.006
7 Serum Fibroblast Growth Factor 21 (FGF-21) levels: Is there a correlation with disease severity and disease progression in m.3243ANG carriers? Presenter: Saskia Koene Saskia Koenea, Paul de Laata, Dennis Vriensb, Doorlene H. van Tienovenc, André M. Brandtc, Fred C.G.J. Sweepc, George Bormd, Mirian C.H. Janssena,e, Jan A.M. Smeitinka a Radboud University Nijmegen Medical Centre, Nijmegen Centre for Mitochondrial Disorders, Department of Paediatrics, Geert Grooteplein 10. 6500 HB, PO Box 9101 Nijmegen, The Netherlands1
8 Six minute bicycling test in children with mitochondrial disorders: Feasibility, reliability, validity and responsivity Presenter: Saskia Koene Saskia Koenea, Merel Jansenb, Saskia B. Wortmanna, Maaike C. de Vriesa, Imelda J.M. de Groota,b, Jan Smeitinka a Radboud University Nijmegen Medical Centre, Nijmegen Centre for Mitochondrial Disorders, Department of Paediatrics, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands1 b Radboud University Nijmegen Medical Centre, Nijmegen Centre for Evidence Based Practice, Radboud University Nijmegen Medical Centre, The Netherlands 1 www.ncmd.nl. Abstract Rationale: More and more therapeutic studies are being performed in children with mitochondrial diseases. To measure the effect of these therapies, it is important to have sensitive and responsive outcome measures. To date, no gold standard outcome measures exist for measuring disease severity in mitochondrial disorders. Most tests that
900
Abstracts
are used to date do not want patients and parents to experience as the most burdensome symptoms in the activities of daily life, namely fatigue and lack of energy. Moreover, the tests that are being used, namely the 6-minute walking test and bicycle ergometry, are not feasible in a large proportion of the more severely affected patients. The six minute (motor-)assisted leg and arm cycling test (A6MCT), developed in our centre, is a non-invasive and quantifiable method to measure endurance in ambulatory and non-ambulatory patients. The test has been shown to be feasible and safe in non-ambulatory boys with Duchenne muscular dystrophy. Objective: This study aimed to test psychometric properties (feasibility, validity, test–retest reproducibility, responsivity) of the A6MCT in ambulatory children with a mitochondrial disease. Study design: Four tests were performed subsequently: the A6MCT (arms and legs in randomized sequence), the 6-minute walking test, timed up and go tests and the Motor Function Measure. Correlations between the A6MCT and the results of the latter three tests were used to indicate validity. During the assisted 6 minute cycling test, fatigue was monitored by measuring heart rate and subjective fatigue. Patients were asked to repeat the cycling tests and the walking test within 2 weeks to test test–retest reproducibility. All tests are currently repeated to measure responsivity after 6 months. Results: Nine patients between the ages of 6–13 years participated in the study. The A6MCT was feasible in all patients without developmental delay. The two patients with mental retardation (developmental age of 4–5 years) were not able to understand and concentrate on the test. There were no serious complications of the A6MCT, though most patients reported fatigue and muscle pain the day after our study.
skinned fibers from the human colorectal cancer tissue samples. This kind of malignant tissue sample is unique because all the tissues are preserved and the samples contain all the microenvironment surrounding the tumor cells including the supporting stromal cells which, for example, are missing in the case of homogenous tumor cell lines. In studies of complex metabolic systems Metabolic Control Analysis is widely used to determine whether a given enzyme exerts high or low control on metabolic flux. For this reason the flux control coefficients are determined on every metabolic step in the system giving us a full picture on the system. In the case of human colorectal cancer all the flux control coefficients are high which indicates that the respiratory chain components are not arranged normally in the cancer cells. These high flux control coefficients have been also seen in other tumors for example in human breast cancer. Our results also show that human colorectal cancer is oxidative and not glycolytic tumor. This is also confirmed by much higher ADP activated respiration rates on human colorectal cancer then on control tissue.
doi:10.1016/j.mito.2013.07.008
Abstract Objective: The aim of this study was to determine the presence and extent of sleep disordered breathing (SDB) in children with mitochondrial disease. Methods: We describe the symptoms, sleep architecture, sleeprelated breathing and movement abnormalities in 18 children (1.5 to 18 years of age, 61% male) with mitochondrial disease who underwent overnight polysomnography based on retrospective chart review. SDB was defined as respiratory disturbance index (RDI) of N1.5 events per hour; obstructive sleep apnea (OSA) as obstructive apnea index of N1 events per hour or apnea hypopnea index (AHI) of N1.5 events per hour; central sleep apnea (CSA) as central apnea index (CAI) of N3 events per hour; sleep hypoventilation as end tidal carbon dioxide (ETCO2) N50 Torr for N25% of total sleep time; and hypoxemia as oxygen saturation nadir of b80% or if patient required supplemental oxygen during the study. Periodic limb movement index of N5 per hour was considered abnormal. Results: Of the 18 children with mitochondrial disease, the most common indication for polysomnography was excessive somnolence or fatigue (61%, N = 11) followed by snoring (39%, N = 7) then sleep movement complaints (17%, N = 3). Polysomnographic measurements showed that 50% (N = 9) had SDB, 33% (N = 6) with OSA, none had CSA, 11% (N = 2) with sleep hypoventilation, and 11% (N = 2) had hypoxemia. Increased periodic limb movements were detected in 11% (N = 2) of the subjects. Conclusion: SDB appears to be a common but an under recognized finding among children with mitochondrial disease. Fatigue is a major complaint in patients with mitochondrial disease and SDB may be contributing in some cases. SBD may also lead to significant cardiovascular, neurocognitive and metabolic effects, potentially worsening the underlying disease morbidity. As such, early detection of SDB utilizing polysomnography, should be performed to assist in identification of children with mitochondrial disease who could benefit from sleeprelated interventions.
9 Regulation of respiration of human colorectal cancer: Application of metabolic control analysis Presenter: Andrus Kaldma Andrus Kaldmaa,f, Andre Koita,f, Igor Ševtšuka, Vladimir Tšekulajeva, Kersti Teppa, Natalja Timohhinaa, Jelena Bogovskajac, Vahur Valverec,d, Valdur Saksa,b, ja Tuuli Kaambrea,e a Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia b Laboratory of Fundamental and Applied Bioenergetics, Joseph Fourier University, Grenoble, France c Oncology and Hematology Clinic at the North Estonia Medical Centre, Tallinn, Estonia d Competence Centre for Cancer Research, Tallinn, Estonia e Tallinn University, Institute of Mathematics and Natural Sciences, Tallinn, Estonia f Department of Gene Technology, Tallinn University of Technology, Estonia E-mail: [email protected] Abstract: Colorectal cancer is one of most common cancer types resulting in premature death in humans. Poor understanding of underlying mechanisms results in low efficiency in treatment. Glycolysis has been considered as the main energy metabolism pathway in malignant tissues since the discovery of high glycolysis in the presence of oxygen in tumor cells by Otto Warburg where tumor cells produce in aerobic conditions high amounts of lactate. Recent studies however, have proposed a new hypothesis of two-compartment tumor metabolism where supporting host cells feed the cancer cells with energy. These supporting stromal cells with high glycolysis produce substrates for cancer cells to be used in OXPHOS. This model explains the high lactate levels and up regulation of OXPHOS in the main tumor cells. In our study we analyzed intraoperational tissue samples from human colorectal cancer patients. We used oxygraphy and made
doi:10.1016/j.mito.2013.07.009
10 Sleep disordered breathing in children with mitochondrial disease Presenter: Cindy Jon Ricardo A. Mosquera, Mary Kay Koenig, Justyna Chevallier, Susan E. Pacheco, Cindy Jon University of Texas — Houston, United States
doi:10.1016/j.mito.2013.07.010
transfer to prevent the transmission of mitochondrial disorders in humans. doi:10.1016/j.mito.2013.07.005
6 Towards harmonization of outcome measures in children with mitochondrial disorders Presenter: Saskia Koene Saskia Koenea, Merel Jansenb, Chris M. Verhaaka,c, Remco L.A. de Vruehd, Imelda J.M. de Groota,b, Jan A.M. Smeitinka a Radboud University Nijmegen Medical Centre, Nijmegen Centre for Mitochondrial Disorders, Department of Paediatrics, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands1 b Radboud University Nijmegen Medical Centre, Nijmegen Centre of Evidence Based Practice, Department of Rehabilitation, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands c Radboud University Nijmegen Medical Centre, Department of Medical Psychology, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands d Rare disease matters, Leiden, The Netherlands 1 www.ncmd.nl. Abstract: A clinical trial is only as reliable as its outcomes, therefore the careful and systematic selection of outcome measures is extremely important. Currently, the selection of outcome measures for clinical trials designed to evaluate new drugs in patients with mitochondrial disorders is inefficient and is not addressed systematically. Given that meaningful data can be obtained only from trials in which outcomes are assessed using valid instruments, one should first focus on the validation of a set of selected instruments in the target population. We aimed to systematically select robust outcome measures that are relevant to all patients. We composed a toolbox with outcome measures based on a primary search for possible instruments using an extensive search of published literature. Subsequently, we reduced this toolbox using strict criteria that were adapted from the US Food and Drug Administration. The product of our study is a toolbox with clinically relevant and psychometrically robust instruments for performing clinical research in children with mitochondrial disorders. In coming years, more experience using these outcome measures in children with various mitochondrial disease phenotypes must be obtained before reliable conclusions regarding the validity of these instruments can be drawn.
899
b
Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Geert Grooteplein 10. 6500 HB, PO Box 9101, Nijmegen, The Netherlands c Radboud University Nijmegen Medical Centre, Department of Laboratory Medicine, Geert Grooteplein 10. 6500 HB, PO Box 9101, Nijmegen, The Netherlands d Radboud University Nijmegen Medical Centre, Department of Epidemiology, Biostatistics and Health Technology Assessment, Geert Grooteplein 10. 6500 HB, PO Box 9101 Nijmegen, The Netherlands e Radboud University Nijmegen Medical Centre, Department of General Internal Medicine, Geert Grooteplein 10. 6500 HB, PO BOX 9101, Nijmegen, The Netherlands 1 www.ncmd.nl.
Abstract: The m.3243ANG nucleotide change is one of the most commonly detected mitochondrial DNA mutations. Patients harbouring this mutation display a widely variable phenotype, ranging from fullblown MELAS/MIDD syndrome with mitochondrial encephalopathy, lactic acidosis and stroke-like episodes or maternally inherited diabetes and deafness to no complaints at all. Since the maternal relatives of patients with the m.3243ANG, with a few exceptions of sporadic cases reported, carry the mutation, they are also at risk of developing clinical symptoms. Currently, the heteroplasmy percentage of the mutation is used to predict disease development of these dormant carriers, but this parameter is known to have a weak correlation with the severity of the disease. In a previous study, Fibroblast Growth Factor 21 (FGF-21) was found to be a sensitive and specific biomarker for the presence of muscle-manifesting mitochondrial disease. In this study, we investigated the value of this biomarker in indicating disease severity and disease progression of m.3243ANG carriers in a large cohort of patients with the m.3243ANG mutation and their maternal relatives. We used the Newcastle Mitochondrial Disease Scale to measure general disease severity and disease progression after one year. Results are currently under statistical analysis. Reference Suomalainen A, Elo JM, Pietilainen KH, Hakonen AH, Sevastianova K, Korpela M, et al. FGF-21 as a biomarker for muscle-manifesting mitochondrial respiratory chain deficiencies: a diagnostic study. Lancet Neurol. 2011 Sep;10(9):806-18. doi:10.1016/j.mito.2013.07.007
Reference Koene S, Jansen M, Verhaak CM, de Groot, IJM, Smeitink JAM. Towards standardization of Outcome Measures in Children with Mitochondrial Disorders. Submitted for publication to Developmental Medicine and Child Neurology. doi:10.1016/j.mito.2013.07.006
7 Serum Fibroblast Growth Factor 21 (FGF-21) levels: Is there a correlation with disease severity and disease progression in m.3243ANG carriers? Presenter: Saskia Koene Saskia Koenea, Paul de Laata, Dennis Vriensb, Doorlene H. van Tienovenc, André M. Brandtc, Fred C.G.J. Sweepc, George Bormd, Mirian C.H. Janssena,e, Jan A.M. Smeitinka a Radboud University Nijmegen Medical Centre, Nijmegen Centre for Mitochondrial Disorders, Department of Paediatrics, Geert Grooteplein 10. 6500 HB, PO Box 9101 Nijmegen, The Netherlands1
8 Six minute bicycling test in children with mitochondrial disorders: Feasibility, reliability, validity and responsivity Presenter: Saskia Koene Saskia Koenea, Merel Jansenb, Saskia B. Wortmanna, Maaike C. de Vriesa, Imelda J.M. de Groota,b, Jan Smeitinka a Radboud University Nijmegen Medical Centre, Nijmegen Centre for Mitochondrial Disorders, Department of Paediatrics, Geert Grooteplein 10, 6500 HB, PO Box 9101, Nijmegen, The Netherlands1 b Radboud University Nijmegen Medical Centre, Nijmegen Centre for Evidence Based Practice, Radboud University Nijmegen Medical Centre, The Netherlands 1 www.ncmd.nl. Abstract Rationale: More and more therapeutic studies are being performed in children with mitochondrial diseases. To measure the effect of these therapies, it is important to have sensitive and responsive outcome measures. To date, no gold standard outcome measures exist for measuring disease severity in mitochondrial disorders. Most tests that
900
Abstracts
are used to date do not want patients and parents to experience as the most burdensome symptoms in the activities of daily life, namely fatigue and lack of energy. Moreover, the tests that are being used, namely the 6-minute walking test and bicycle ergometry, are not feasible in a large proportion of the more severely affected patients. The six minute (motor-)assisted leg and arm cycling test (A6MCT), developed in our centre, is a non-invasive and quantifiable method to measure endurance in ambulatory and non-ambulatory patients. The test has been shown to be feasible and safe in non-ambulatory boys with Duchenne muscular dystrophy. Objective: This study aimed to test psychometric properties (feasibility, validity, test–retest reproducibility, responsivity) of the A6MCT in ambulatory children with a mitochondrial disease. Study design: Four tests were performed subsequently: the A6MCT (arms and legs in randomized sequence), the 6-minute walking test, timed up and go tests and the Motor Function Measure. Correlations between the A6MCT and the results of the latter three tests were used to indicate validity. During the assisted 6 minute cycling test, fatigue was monitored by measuring heart rate and subjective fatigue. Patients were asked to repeat the cycling tests and the walking test within 2 weeks to test test–retest reproducibility. All tests are currently repeated to measure responsivity after 6 months. Results: Nine patients between the ages of 6–13 years participated in the study. The A6MCT was feasible in all patients without developmental delay. The two patients with mental retardation (developmental age of 4–5 years) were not able to understand and concentrate on the test. There were no serious complications of the A6MCT, though most patients reported fatigue and muscle pain the day after our study.
skinned fibers from the human colorectal cancer tissue samples. This kind of malignant tissue sample is unique because all the tissues are preserved and the samples contain all the microenvironment surrounding the tumor cells including the supporting stromal cells which, for example, are missing in the case of homogenous tumor cell lines. In studies of complex metabolic systems Metabolic Control Analysis is widely used to determine whether a given enzyme exerts high or low control on metabolic flux. For this reason the flux control coefficients are determined on every metabolic step in the system giving us a full picture on the system. In the case of human colorectal cancer all the flux control coefficients are high which indicates that the respiratory chain components are not arranged normally in the cancer cells. These high flux control coefficients have been also seen in other tumors for example in human breast cancer. Our results also show that human colorectal cancer is oxidative and not glycolytic tumor. This is also confirmed by much higher ADP activated respiration rates on human colorectal cancer then on control tissue.
doi:10.1016/j.mito.2013.07.008
Abstract Objective: The aim of this study was to determine the presence and extent of sleep disordered breathing (SDB) in children with mitochondrial disease. Methods: We describe the symptoms, sleep architecture, sleeprelated breathing and movement abnormalities in 18 children (1.5 to 18 years of age, 61% male) with mitochondrial disease who underwent overnight polysomnography based on retrospective chart review. SDB was defined as respiratory disturbance index (RDI) of N1.5 events per hour; obstructive sleep apnea (OSA) as obstructive apnea index of N1 events per hour or apnea hypopnea index (AHI) of N1.5 events per hour; central sleep apnea (CSA) as central apnea index (CAI) of N3 events per hour; sleep hypoventilation as end tidal carbon dioxide (ETCO2) N50 Torr for N25% of total sleep time; and hypoxemia as oxygen saturation nadir of b80% or if patient required supplemental oxygen during the study. Periodic limb movement index of N5 per hour was considered abnormal. Results: Of the 18 children with mitochondrial disease, the most common indication for polysomnography was excessive somnolence or fatigue (61%, N = 11) followed by snoring (39%, N = 7) then sleep movement complaints (17%, N = 3). Polysomnographic measurements showed that 50% (N = 9) had SDB, 33% (N = 6) with OSA, none had CSA, 11% (N = 2) with sleep hypoventilation, and 11% (N = 2) had hypoxemia. Increased periodic limb movements were detected in 11% (N = 2) of the subjects. Conclusion: SDB appears to be a common but an under recognized finding among children with mitochondrial disease. Fatigue is a major complaint in patients with mitochondrial disease and SDB may be contributing in some cases. SBD may also lead to significant cardiovascular, neurocognitive and metabolic effects, potentially worsening the underlying disease morbidity. As such, early detection of SDB utilizing polysomnography, should be performed to assist in identification of children with mitochondrial disease who could benefit from sleeprelated interventions.
9 Regulation of respiration of human colorectal cancer: Application of metabolic control analysis Presenter: Andrus Kaldma Andrus Kaldmaa,f, Andre Koita,f, Igor Ševtšuka, Vladimir Tšekulajeva, Kersti Teppa, Natalja Timohhinaa, Jelena Bogovskajac, Vahur Valverec,d, Valdur Saksa,b, ja Tuuli Kaambrea,e a Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia b Laboratory of Fundamental and Applied Bioenergetics, Joseph Fourier University, Grenoble, France c Oncology and Hematology Clinic at the North Estonia Medical Centre, Tallinn, Estonia d Competence Centre for Cancer Research, Tallinn, Estonia e Tallinn University, Institute of Mathematics and Natural Sciences, Tallinn, Estonia f Department of Gene Technology, Tallinn University of Technology, Estonia E-mail: [email protected] Abstract: Colorectal cancer is one of most common cancer types resulting in premature death in humans. Poor understanding of underlying mechanisms results in low efficiency in treatment. Glycolysis has been considered as the main energy metabolism pathway in malignant tissues since the discovery of high glycolysis in the presence of oxygen in tumor cells by Otto Warburg where tumor cells produce in aerobic conditions high amounts of lactate. Recent studies however, have proposed a new hypothesis of two-compartment tumor metabolism where supporting host cells feed the cancer cells with energy. These supporting stromal cells with high glycolysis produce substrates for cancer cells to be used in OXPHOS. This model explains the high lactate levels and up regulation of OXPHOS in the main tumor cells. In our study we analyzed intraoperational tissue samples from human colorectal cancer patients. We used oxygraphy and made
doi:10.1016/j.mito.2013.07.009
10 Sleep disordered breathing in children with mitochondrial disease Presenter: Cindy Jon Ricardo A. Mosquera, Mary Kay Koenig, Justyna Chevallier, Susan E. Pacheco, Cindy Jon University of Texas — Houston, United States
doi:10.1016/j.mito.2013.07.010