The Clinical, Radiographic And Pathological Analysis Of MELAS And Its Pathogenesis Resulted From NO Decrease

Background and purpose:Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-likeepisodes(MELAS) syndrome is the more common type of a mitochondrialmyopathy, encephalopathy(ME), The disease as an independent mitochondrialdiseases was first reported by Pavlakis in1984. The neuromuscular pathologywork carried out in recent years, domestic coverage about the disease graduallyincreased, and higher morbidity and mortality rate of this disease, so earlydiagnosis and treatment is very important, the complex clinical manifestationsand the lack of specificity, early imaging findings is not typical, so it can easilybe misdiagnosed, In this study,by analyzing the clinical manifestations, imagingcharacteristics and muscle histopathological changes of MELAS syndrome, toimprove clinicians’ understanding of the disease, to early diagnosis andtreatment, to reduce misdiagnosis and the suffering of patients, to alleviate theburden on the family and society.Although depth understanding of the genetic, biochemical andpathological changes, its pathogenesis is not very clear. There are severaltheories:(1) mitochondrial disease theory,(2) mitochondrial disease doctrine,(3) non-ischemic neurovascular cell theory, but it can not fully explain thepathogenesis of MELAS syndrome, therefore, the exact pathogenesis is stillunder study. In this study, by measuring the serum concentration of NO,explore another possible pathogenesis of MELAS syndrome.Methods:Basing MELAS syndrome clinical diagnostic criteria, there are10patients,which collect from June2008to March2012Bethune First Hospital of Jilin University, Department of Neurology, outpatient and inpatient Collection ofclinical data: gender, age, medical history, physical signs, blood lactate,electrophysiological examination, imaging and muscle biopsy. Analysis ofMELAS patients with clinical, radiographic, and muscle pathological features.Acquisition of10patients with MELAS serum stored at (-80℃) as theexperimental group, while collecting10healthy human serum (stored at-80℃)for the control group, measured the serum NO content of experimental groupand the control group by nitrate reductase method.Independent t test was usedfor comparative analysis the NO content of the experimental group and thecontrol group.Results:The main clinical manifestations of MELAS syndrome of focal orgeneralized seizures, stroke-like episodes, cognitive dysfunction, hearing andvisual impairments, the movement can not be tolerated, and blood lactate levels.Brain imaging examination revealed multiple lesions in the temporal, occipital,parietal cortex back at head MRI performance for long T1, long T2signal.10patients with MELAS, Nine cases of muscle biopsy show a large number ofRRF, typical or atypical RRF.10patients with MELAS serum NO content compared with normal humanserum NO content decreased, which has a statistically significant (P＜0.01)but no significant correlation between the serum concentration of NO and theage of onset, duration, frequency of onset and pathological changes.Conclusion:MELAS syndrome is a brain and muscle energy metabolism dysfunctionsyndrome, lactic acidosis and stroke-like hair as features. The clinicalmanifestations of complex and diverse, easily misdiagnosed, and its diagnosis is based on clinical manifestations, imaging features and combined skeletalmuscle biopsy which found the RRF or abnormal mitochondrial aggregation,clinical diagnosis can be obtained.The decrease in NO content may be one of the pathogenesis of MELASsyndrome,easily obtained, lower costs, and clinical manifestations, imagingstudies, the combination of muscle biopsy, the MELAS patients can accessearly diagnosis and reduce misdiagnosis, and bring new hope to the treatmentof MELAS patients.