This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. ABSTRACT: The Mitochondrial myopathy, Encephalomyopathy, Lactic acidosis, with Stroke-like episodes (MELAS) syndrome is a disorder of mitochondrial dysfunction that has a broad spectrum of symptoms and variable age of onset. Common manifestations include exercise intolerance, stroke-like episodes, seizures, ragged red fibers, lactic acidosis, and dementia, with 75% of cases presenting before 20 years of age. The prevalence of stroke-like episodes approaches 99%. MELAS syndrome is one of the most frequent maternally inherited mitochondrial disorders with a minimal prevalence of 16.3/100,000. The pathogenesis of the stroke-like episodes is not clear. It is believed that epithelial dysfunction may lead to nitric oxide deficiency and ischemic events in the microvasculature. Both arginine and citrulline act as nitric oxide precursors. It has been reported that plasma arginine and citrulline levels are lower in subjects with MELAS syndrome and that administration of arginine leads to clinical improvement in the acute episodes and in the interictal state. However, there are no clinical studies evaluating the arginine flux and nitric oxide production or the effect of the administration of arginine or citrulline on nitric oxide production in subjects with MELAS syndrome. Thus, we designed a case control prospective study to determine arginine flux and nitric oxide production via a stable isotope infusion technique in subjects with MELAS syndrome and control subjects, both cohorts will have a baseline study without any supplementation of arginine or citrulline, and subjects with MELAS syndrome will be studied with arginine and with citrulline supplementation.
The aims are to see whether nitric oxide production is lower in subjects with MELAS syndrome, whether arginine and citrulline supplementation will increase the nitric oxide production, and whether citrulline supplementation will increase nitric oxide production more than arginine supplementation secondary to arginine compartmentalization. If we were to demonstrate that subjects with MELAS syndrome have lower nitric oxide production than control subjects and that arginine and/or citrulline supplementation increases nitric oxide production, with either arginine or citrulline having a superior effect, the outcome of this clinical research will establish evidence to the usefulness of such supplementation in the treatment and prevention of stroke-like episodes in subjects with MELAS syndrome. I. HYPOTHESIS Hypothesis (A): Subjects with MELAS syndrome have epithelial dysfunction altering the nitric oxide metabolism, leading to decreased nitric oxide production. Hypothesis (B): Administration of L-arginine and L-citrulline, as nitric oxide precursors, will increase production of nitric oxide in subjects with MELAS syndrome. Hypothesis (C): Arginine is compartmentalized in a sub-cellular compartment where arginine metabolism takes place, thus there may not be free exchange of circulating arginine. Rather it depends on the local citrulline pool to replenish the arginine pool for nitric oxide synthesis. Therefore L-citrulline supplementation will increase nitric oxide production to higher degree than L-arginine supplementation. II.
SPECIFIC AIMS Specific aim (A): To determine whether subjects with MELAS syndrome have lower nitric oxide production than control subjects.
Specific aim (B): To test whether administration of L-arginine or L-citrulline to subjects with MELAS Syndrome will increase nitric oxide production.
Specific aim (C): To determine whether L-citrulline supplementation will increase nitric oxide production to a higher degree than L-arginine supplementation.

National Institute of Health (NIH)
National Center for Research Resources (NCRR)
General Clinical Research Centers Program (M01)
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Baylor College of Medicine
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Hunsaker, Sanita L; Garland, Beth H; Rofey, Dana et al. (2018) A Multisite 2-Year Follow Up of Psychopathology Prevalence, Predictors, and Correlates Among Adolescents Who Did or Did Not Undergo Weight Loss Surgery. J Adolesc Health 63:142-150
Lanzieri, Tatiana M; Chung, Winnie; Leung, Jessica et al. (2018) Hearing Trajectory in Children with Congenital Cytomegalovirus Infection. Otolaryngol Head Neck Surg 158:736-744
Bollard, Catherine M; Tripic, Tamara; Cruz, Conrad Russell et al. (2018) Tumor-Specific T-Cells Engineered to Overcome Tumor Immune Evasion Induce Clinical Responses in Patients With Relapsed Hodgkin Lymphoma. J Clin Oncol 36:1128-1139
Michalsky, Marc P; Inge, Thomas H; Jenkins, Todd M et al. (2018) Cardiovascular Risk Factors After Adolescent Bariatric Surgery. Pediatrics 141:
Lau, Chantal (2018) Breastfeeding Challenges and the Preterm Mother-Infant Dyad: A Conceptual Model. Breastfeed Med 13:8-17
Gururangan, Sridharan; Reap, Elizabeth; Schmittling, Robert et al. (2017) Regulatory T cell subsets in patients with medulloblastoma at diagnosis and during standard irradiation and chemotherapy (PBTC N-11). Cancer Immunol Immunother 66:1589-1595
Lanzieri, T M; Leung, J; Caviness, A C et al. (2017) Long-term outcomes of children with symptomatic congenital cytomegalovirus disease. J Perinatol 37:875-880
El-Hattab, Ayman W; Zarante, Ana Maria; Almannai, Mohammed et al. (2017) Therapies for mitochondrial diseases and current clinical trials. Mol Genet Metab 122:1-9
Jin, Haoxing Douglas; Demmler-Harrison, Gail J; Coats, David K et al. (2017) Long-term Visual and Ocular Sequelae in Patients With Congenital Cytomegalovirus Infection. Pediatr Infect Dis J 36:877-882
Oh, Sam S; Du, Randal; Zeiger, Andrew M et al. (2017) Breastfeeding associated with higher lung function in African American youths with asthma. J Asthma 54:856-865

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