Activated mTOR signaling pathway in myofibers with inherited metabolic defect might be an evidence for mTOR inhibition therapies / 中华医学杂志(英文版)

BACKGROUND@#Abnormally activated mechanistic target of rapamycin (mTOR) pathway has been reported in several model animals with inherited metabolic myopathies (IMMs). However, the profiles of mTOR pathway in skeletal muscles from patients are still unknown. This study aimed to analyze the activity of mTOR pathway in IMMs muscles.@*METHODS@#We collected muscle samples from 25 patients with mitochondrial myopathy (MM), lipid storage disease (LSD) or Pompe disease (PD). To evaluate the activity of mTOR pathway in muscle specimens, phosphorylation of S6 ribosomal protein (p-S6) and p70S6 kinase (p-p70S6K) were analyzed by Western blotting and immunohistochemistry.@*RESULTS@#Western blotting results showed that p-p70S6K/p70S6K in muscles from LSD and MM was up-regulated when compared with normal controls (NC) (NC vs. LSD, U = 2.000, P = 0.024; NC vs. MM: U = 6.000, P = 0.043). Likewise, p-S6/S6 was also up-regulated in muscles from all three subgroups of IMMs (NC vs. LSD, U = 0.000, P = 0.006; NC vs. PD, U = 0.000, P = 0.006; NC vs. MM, U = 1.000, P = 0.007). Immunohistochemical study revealed that p-S6 was mainly expressed in fibers with metabolic defect. In MM muscles, most p-S6 positive fibers showed cytochrome C oxidase (COX) deficiency (U = 5.000, P = 0.001). In LSD and PD muscles, p-S6 was mainly overexpressed in fibers with intramuscular vacuoles containing lipid droplets (U = 0.000, P = 0.002) or basophilic materials (U = 0.000, P = 0.002).@*CONCLUSION@#The mTOR pathway might be activated in myofibers with various metabolic defects, which might provide evidence for mTOR inhibition therapy in human IMMs.

Clinical, Neuroimaging, and Pathological Analyses of 13 Chinese Leigh Syndrome Patients with Mitochondrial DNA Mutations / 中华医学杂志(英文版)

Background@#Leigh syndrome (LS) is a rare disease caused by mitochondrial defects and has high phenotypic and genotypic heterogeneity. We analyzed the clinical symptoms, neuroimaging, muscular histopathology, and genotypes of 13 Chinese LS patients with mitochondrial DNA (mtDNA) mutations.@*Methods@#Mutations in mtDNA were identified by targeted sequencing. The brain imaging features on magnetic resonance imaging (MRI) were analyzed. The levels of lactate in fasting blood and cerebrospinal fluid (CSF) were routinely tested. The levels of urinary organic acids, plasma amino acids, and acylcarnitines were examined with gas chromatography-mass spectrometry and tandem mass spectrometry. The histopathological traits of skeletal muscles were analyzed under microscope.@*Results@#Among 13 patients, mutations of MT-NDs (n = 8) and MT-ATP6 (n = 4) genes were most common. Strabismus (8/13), muscle weakness (8/13), and ataxia (5/13) were also common, especially for the patients with late-onset age after 2 years old. However, respiratory distress was common in patients with early-onset age before 2 years old. The most frequently affected brain area in these patients was the brain stem (12/13), particularly the dorsal part of midbrain, followed by basal ganglia (6/13), thalamus (6/13), cerebellum (5/13), and supratentorial white matter (2/13). Besides, the elevated lactate levels in CSF (6/6) were more common than those in serum (7/13). However, the analysis of abnormal plasma amino acid and urinary organic acid showed limited results (0/3 and 1/4, respectively). Muscular histopathology showed mitochondrial myopathy in the three late-onset patients but not in the early-onset ones.@*Conclusions@#Noninvasive genetic screening is recommended for mtDNA mutations in MT-NDs and MT-ATP6 genes in patients with ophthalmoplegia, muscle weakness, ataxia, and respiratory disorder. Furthermore, the lactate detection in CSF and the brain MRI scanning are suggested as the diagnosis methods for LS patients with mtDNA mutations.

Upregulation of Interleukin 21 and Interleukin 21 Receptor in Patients with Dermatomyositis and Polymyositis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The immunopathologic mechanism underlying dermatomyositis (DM) and polymyositis (PM) remains poorly understood. Many cytokines play a pathogenic role in DM and PM. Interleukin 21 (IL-21) has a pleiotropic effect on inflammation regulation. This study aimed to detect the serum IL-21 level and investigate the expression of IL-21 and IL-21 receptor (IL-21R) in muscle tissues of patients with DM and PM.</p><p><b>METHODS</b>Biopsied muscle samples were obtained from 11 patients with DM, 12 with PM, and six controls; mRNA levels of IL-21 and IL-21R were analyzed by real-time quantitative reverse transcription-polymerase chain reaction; and immunohistochemical staining was used to evaluate the protein expression of IL-21 and IL-21R. Serum samples were obtained from 36 patients with DM, 19 with PM, and 20 healthy controls. The serum IL-21 level was detected by enzyme-linked immunosorbent assay.</p><p><b>RESULTS</b>The expression of IL-21 was upregulated in patients with DM and PM. The IL-21 mRNA level was significantly increased in muscle tissues of patients with DM and PM (DM vs. control, P= 0.001; PM vs. control, P= 0.001), whereas IL-21R mRNA level in patients with DM/PM was not statistically different from that of healthy controls. Immunohistochemical staining showed both IL-21 and IL-21R were significantly expressed in the inflammatory cells in muscle tissues of patients with DM and PM. The serum IL-21 level was also significantly higher in patients with DM/PM than in controls (DM vs. control, 49.12 [45.28, 60.07] pg/ml vs. 42.54 [38.69, 48.85] pg/ml, P= 0.001; PM vs. control, 50.77 [44.19, 60.62] pg/ml vs. 42.54 [38.69, 48.85] pg/ml, P= 0.005).</p><p><b>CONCLUSIONS</b>IL-21 expression is upregulated in patients with DM and PM in both muscle tissue and serum. In addition, IL-21R protein is highly expressed in affected muscle tissues of patients with DM and PM. IL-21 may play a pathogenic role through IL-21R in patients with DM and PM.</p>

Primary angiitis of the central nervous system: a case report / 中华医学杂志(英文版)

Primary angiitis of the central nervous system is a rare and difficult entity. Here we represented the clinical and pathological features of a patient with little response to steroid before definite diagnosis. The 50-year-old male had a fluctuating disease course for more than 3 years. He presented visual disorders, seizure, cognitive impairment, hypersomnia, unsteady gait, dysphasia, dysphagia, and incontinence. Magnetic resonance imaging showed multiple, supratentorial and infratentorial abnormal signals, while cerebrospinal fluid and cerebral angiography were normal. Magnetic resonance spectrum showed a decrease of N-acetyl-aspartate. Brain biopsy revealed nongranulomatous lymphatic vasculitis with reactive gliosis, cicatrization, demyelination and focal hemorrhages.

Mitochondrial ND5 as the causative gene of Leight syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To report a Chinese Han family with two patients of Leigh syndrome (LS) and to scan the mutation in mitochondrial DNA(mtDNA).</p><p><b>METHODS</b>The clinical features and the laboratory findings were summarized. Mitochondrial DNA chip and direct sequencing were performed to detect the mutation in entire mtDNA.</p><p><b>RESULTS</b>Failure of thrive, psychomotor retardation, hypotonia and weakness, cerebellar ataxia, and seizure were the main manifestations of the family. Brain magnetic resonance imaging (MRI) showed lesions at midbrain, periaqueductal gray matter, dentate nuclei of cerebellar and thalami. The levels of lactic acid and pyruvate were mildly abnormal. The mutation of ND5*13513 G to A was identified in the LS family.</p><p><b>CONCLUSION</b>Patients with ND5*13513 G to A mutation may have a characteristic clinical course and ND5 *13513 G to A might be a preferential candidate mutation of Leigh syndrome.</p>

Clinical and biopsy-based myopathological features of 5 cases with centronuclear myopathy / 中华儿科杂志

<p><b>OBJECTIVE</b>To analyze the clinical and pathological features of the centronuclear myopathy (CNM) in 5 Chinese patients and evaluate their diagnostic and differential diagnostic value.</p><p><b>METHODS</b>A standard series of histochemical and enzymohistochemical investigations were performed on all muscle specimens of CNM cases obtained via biopsy. The clinical manifestations and myopathological features of 5 CNM patients were retrospectively analyzed.</p><p><b>RESULTS</b>The age of onset ranged from 3 to 12 years. All patients primarily presented with limb girdle muscle weakness. In 3 patients extraocular muscles, facial muscles and cervical muscles were affected, respectively. The proximal muscles were affected more seriously than the distal and the lower limbs more seriously than the upper. Tendon reflex was reduced and no evident muscular atrophy was seen. The course of the disease ranged from 4 to 46 years and progressed slowly. The ability of walking could be maintained for many years and the fast movements such as running and jumping were impaired early. The serum creatine kinase (CK) level was normal or elevated slightly. Electromyography showed myopathic pattern in all cases. Two patients (mother and son) were from the same family and the son's two siblings had similar symptoms indicating autosomal dominant inherited pattern. There was mild variation in fiber size and most small fibers were round. Interstitial tissue increase slightly. Fibers with centrally placed nuclei accounted for 23% - 93%. Neither necrotic and regenerated fibers nor infiltration of inflammatory cells were seen. Type I fiber predominance and hypotrophy were present in all patients. Abnormal arrangement of the sarcoplasmic strands in appearance of "spokes of a wheel", increased oxidative enzyme activity around centronuclear and perinuclear halo were observed in 2 patients by NADH-TR staining.</p><p><b>CONCLUSIONS</b>For the patients who had the onset during the childhood and presented with slow progressive limb girdle muscle weakness, disability of fast movements and normal serum CK level, the possibility of benign congenital myopathy should be considered. High percentage of centronuclear fibers as well as type I fiber predominance and hypotrophy in muscle biopsy pathology may provide a morphological evidence for the definite diagnosis of CNM.</p>

Clinical,neuroimaging and myopathological features of MELAS:a retrospective analysis of 31 patients / 中华神经科杂志

Objective To investigate the clinical,neuroimaging and myopathological features of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes(MELAS).Methods The clinical manifestations,neuroimaging and myopathological features of 31 patients with MELAS diagnosed in our Neuromuscular Center in the recent 7 years were retrospectively analyzed.A3243G point mutations were analyzed by RFLP method in 10 patients.Results ①Clinical features:There were 18 male patients and 13 female patients.The age of onset ranged from 3 to 43 years,averaging 21.9 years.The averaged duration was 4.9 years.Thirteen patients in this group had family history of maternal inheritance pattern.The main clinical manifestations included short stature(26 patients),recurrent headache and vomiting(24 patients), muscle weakness(22 patients),epileptic seizure(21 patients),cognitive decline(19 patients),visual disturbance(17 patients),sensorineural deafness(16 patients),ataxia(6 patients),psychiatric symptom (8 patients),external ophathalmoplegia(2 patients)and diabetes mellitus(9 patients).The serum CK level was slightly elevated in 6 patients,and the fasting blood lactic acid was increased in 15 of the 18 detected patients.②Neuroimaging features:The stroke-like lesions were mostly confined to cerebral cortex, including temporal lobe(24 patients),occipital lobe(21 patients),parietal lobe(12 patients)and frontal lobe(4 patients).Three patients had deep white matter involvement.Migrating stroke-like lesions were confirmed in 4 patients by repeated cranial CT/MRI examination.In addition,cerebral atrophy(17 patients)and bilateral basilar ganglion calcification(11 patients)were found.③Myopathological features: Scattered ragged red fibers(RRF)in various number were found in all the patients by MGT staining.Other founding included strongly SDH-reactive blood vessel(27 patients),COX enzyme deficiency(19 patients), and mild to moderate lipid storage in RRF(20 patients).④MtDNA analysis showed 9 patients with A3243G point mutation in all the detected 13 patients.Conclusion The clinical and neuroimaging features may offer important clue to the diagnosis of MELAS,but a definite diagnosis of MELAS relies on the myopathology and mtDNA mutation analysis.

Therapeutic effects and long term follow-ups in 42 cases of lipid storage myopathy / 中华神经科杂志

Objective To clarify the clinical features,therapeutic strategy and prognosis of lipid storage myopathy (LSM).Methods The clinical data and therapeutic effects of 42 LSM patients were summarized retrospectively.All patients were followed up to evaluate their prognosis.Results Data of short-term therapeutic results of all the 42 patients were available.Thirty-three cases were placed in low- doses prednisone and 9 cases in riboflavin.All patients showed marked and quick improvement of symptoms within one month.Among thirty-two patients followed up for more than one year,26 cases had a full recovery and 6 remained to have intolerance to heavy exercise.Thirteen patients had relapses of muscle weakness in various degrees and most of which were induced by exertion,exposure to coldness and upper respiratory tract infection.In 5 patients the symptoms were recurred for more than one time.Among 13 cases with relapses, 7 had family history.Conclusions Our data suggest that LSM is a treatable disease and well responsive to low-doses prednisone.The disease tends to recur,especially in patients with family history.Glutaric aciduria type Ⅱ should be considered in LSM patients who are responsive well to riboflavin,indicating drug therapeutic strategy for LSM should be based on the etiology of the disease.