Dataset Information

Substrate oxidation and cardiac performance during exercise in disorders of long chain fatty acid oxidation.

ABSTRACT:

Background

The use of long-chain fatty acids (LCFAs) for energy is inhibited in inherited disorders of long-chain fatty acid oxidation (FAO). Increased energy demands during exercise can lead to cardiomyopathy and rhabdomyolysis. Medium-chain triglycerides (MCTs) bypass the block in long-chain FAO and may provide an alternative energy substrate to exercising muscle.

Objectives

To determine the influence of isocaloric MCT versus carbohydrate (CHO) supplementation prior to exercise on substrate oxidation and cardiac workload in participants with carnitine palmitoyltransferase 2 (CPT2), very long-chain acyl-CoA dehydrogenase (VLCAD) and long-chain 3-hydroxyacyl CoA dehydrogenase (LCHAD) deficiencies.

Design

Eleven subjects completed two 45-minute, moderate intensity, treadmill exercise studies in a randomized crossover design. An isocaloric oral dose of CHO or MCT-oil was administered prior to exercise; hemodynamic and metabolic indices were assessed during exertion.

Results

When exercise was pretreated with MCT, respiratory exchange ratio (RER), steady state heart rate and generation of glycolytic intermediates significantly decreased while circulating ketone bodies significantly increased.

Conclusions

MCT supplementation prior to exercise increases the oxidation of medium chain fats, decreases the oxidation of glucose and acutely lowers cardiac workload during exercise for the same amount of work performed when compared with CHO pre-supplementation. We propose that MCT may expand the usable energy supply, particularly in the form of ketone bodies, and improve the oxidative capacity of the heart in this population.

SUBMITTER: Behrend AM

PROVIDER: S-EPMC3253922 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature

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Publications

Substrate oxidation and cardiac performance during exercise in disorders of long chain fatty acid oxidation.

Behrend Annie M AM Harding Cary O CO Shoemaker James D JD Matern Dietrich D Sahn David J DJ Elliot Diane L DL Gillingham Melanie B MB

Molecular genetics and metabolism 20111001 1

<h4>Background</h4>The use of long-chain fatty acids (LCFAs) for energy is inhibited in inherited disorders of long-chain fatty acid oxidation (FAO). Increased energy demands during exercise can lead to cardiomyopathy and rhabdomyolysis. Medium-chain triglycerides (MCTs) bypass the block in long-chain FAO and may provide an alternative energy substrate to exercising muscle.<h4>Objectives</h4>To determine the influence of isocaloric MCT versus carbohydrate (CHO) supplementation prior to exercise ...[more]

PMID: 22030098

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Project description:Long-chain fatty acid oxidation disorders (LC-FAOD) are a group of rare, autosomal recessive genetic disorders that impair conversion of long-chain fatty acids into energy. Here we describe the impact of LC-FAOD in terms of effects on work and school, absenteeism and presenteeism at work, importance of symptoms, physical activity, participation in social activities, and quality of life (QoL). A convenience sample of adults (≥18 years) and caregivers of patients with LC-FAOD was invited to take the online survey (Confirmit). To be included, patients must have been receiving medical care from a healthcare provider for their LC-FAOD, and caregivers must not have been compensated for their care. Degree of physical activity, represented by metabolic equivalents (METs), was calculated using the NHANES Physical Activity Questionnaire. Absenteeism and presenteeism at work were calculated using the WHO Health Productivity Questionnaire. QoL was assessed using the 12-Item Short Form of the Medical Outcomes Survey. Significance was assessed using two tailed independent sample t-tests and z-tests at α = 0.1. Fourteen adults and 30 caregivers of LC-FAOD patients (answering for 37 patients) answered the survey (51 unique respondents). 59.2% of LC-FAOD patients experienced effects on their schooling due to LC-FAOD. 84.2% of working patients experienced effects on their work due to LC-FAOD. 70% of caregivers experienced effects on their work due to their child's LC-FAOD. Unique respondents report that muscle weakness (69%), physical fatigue (49%), and rhabdomyolysis (39%) are the most impactful symptoms of LC-FAOD. Adults (n = 14) scored significantly below the normalized average (50) on both physical (34.51, p < 0.001) and mental (45.27, p = 0.04) component scores of the SF-12 health-related quality of life measure. LC-FAOD impart a high disease impact on patients and their caregivers. In particular, symptoms relating to energy production were rated as highly impactful and limiting. Activities that may be considered normal for many people can prove to be very difficult or impossible for respondents with LC-FAOD, with respondents reporting lower physical and mental health-related quality of life measures than the average American.

Project description:IntroductionDetermining the epidemiology of disease is critical for multiple reasons, including to perform risk assessment, compare disease rates in varying populations, support diagnostic decisions, evaluate health care needs and disease burden, and determine the economic benefit of treatment. However, establishing epidemiological measures for rare diseases can be difficult owing to small patient populations, variable diagnostic techniques, and potential disease and diagnostic heterogeneity. To determine the epidemiology of rare diseases, investigators often develop estimation models to account for missing or unobtainable data, and to ensure that their findings are representative of their desired patient population.MethodsA modeling methodology to estimate the prevalence of rare diseases in one such population-patients with long-chain fatty acid oxidation disorders (LC-FAOD)-as an illustrative example of its applicability.ResultsThe proposed model begins with reliable source data from newborn screening reports and applies to them key modifiers. These modifiers include changes in population growth over time and variable standardization rates of LC-FAOD screening that lead to (1) a confirmed diagnosis and (2) improvements in standards of care and survival estimates relative to the general population. The model also makes necessary assumptions to allow the broad applicability of the estimation of LC-FAOD prevalence, including rates of diagnosed versus undiagnosed patients in the USA over time.ConclusionsAlthough each rare disease is unique, the approach described here and demonstrated in the estimation of LC-FAOD prevalence provides the necessary tools to calculate key epidemiological estimates useful in performing risk assessment analyses; comparing disease rates between different subgroups of people; supporting diagnostic decisions; planning health care needs; comparing disease burden, including cost; and determining the economic benefit of treatment.

Project description:BackgroundLong-chain fatty acid oxidation disorders (LC-FAOD) are a group of rare autosomal-recessive genetic disorders characterized by metabolic deficiencies in which the body is unable to convert long-chain fatty acids into energy. To date, however, there is limited understanding of the patient experience of LC-FAOD.MethodsThe symptoms, observable signs, and quality of life (QoL) impacts associated with LC-FAOD were explored via a focus group (n = 8) and semi-structured interviews (n = 6) with patients and caregivers of patients with LC-FAOD, and interviews (n = 4) with expert clinicians. Data were analyzed via thematic analysis and summarized in a conceptual model.ResultsParticipants reported a wide range of signs and symptoms associated with LC-FAOD, broadly categorized as musculoskeletal, endocrine/nutritional/metabolic, neurological, gastrointestinal/digestive, sensory, cardiovascular, respiratory, urological, and constitutional. LC-FAOD were reported to have a significant impact on various aspects of patients' lives including physical functioning, participation in daily activities, emotional/psychological wellbeing, and social functioning. Lifestyle modifications (such as diet and exercise restrictions) were necessary because of the condition. Symptoms were typically episodic in presentation often arising or exacerbated during catabolic conditions such as prolonged exercise, fasting, physiological stress, and illness/infection. Symptoms were also commonly reported to lead to emergency room visits, hospitalization, and clinical complications.ConclusionLC-FAOD have a considerable impact on patients' lives. There is a high degree of concordance in the signs, symptoms, and impacts of LC-FAOD reported by patients, caregivers, and clinicians; however, there were many symptoms and impacts that were only reported by patients and caregivers, thus demonstrating that insights from patient/caregiver experience data are integral for informing medical product development and facilitating patient-centered care.

Dataset Information

Substrate oxidation and cardiac performance during exercise in disorders of long chain fatty acid oxidation.

Background

Objectives

Design

Results

Conclusions

Publications

Substrate oxidation and cardiac performance during exercise in disorders of long chain fatty acid oxidation.

Similar Datasets

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