Abstract
Cardiomyopathy is a life-threatening condition in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (known as MELAS). However, no effective therapy has been available until now. In the present study cardiac energetics and acute effects of L-arginine (Arg) were evaluated in MELAS patients. The 6 patients with MELAS (M-group) and 6 volunteers (C-group) underwent dynamic C-11 acetate positron emission tomography (PET) imaging. TCA-cycle metabolic rate (k(mono)), myocardial efficiency (double product (DP)/k(mono)), and myocardial blood flow (MBF) were determined before and after L-Arg administration. Baseline k(mono) showed a lower value in the M-group than in the C-group (0.051±0.013 vs 0.070±0.019min(-1), P=0.055). On the other hand, baseline DP/k(mono) was significantly greater in the M-group (1.69±5.9 vs 0.95±1.2×10(5), P=0.004). After L-Arg administration, 4 patients showed significant elevation of k(mono). No relationship was observed between the distribution of k(mono) elevation and the increase in MBF. The TCA cycle metabolic rate is markedly suppressed in MELAS patients, indicating a shift in energy production to the anaerobic pathway, leading to a paradoxical increase in myocardial efficiency. L-Arg can enhance TCA-cycle metabolism, regardless of its vasodilatation effect, and can be used as a treatment for patients with mitochondrial cardiomyopathy.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
