Mitsugu Uematsu

Intramuscular renin–angiotensin system is activated in human muscular dystrophy

To investigate the role of the muscular renin-angiotensin system (RAS) in human muscular dystrophy, we used immunohistochemistry and Western blotting to examine the cellular localization of angiotensin-converting enzyme (ACE), the angiotensin II type 1 receptor (AT1) and the angiotensin II type 2 receptor (AT2) in muscle biopsies from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), and congenital muscular dystrophy (CMD). In normal muscle, ACE was expressed in vascular endothelial cells and neuromuscular junctions (NMJs), whereas AT1 was immunolocalized to the smooth muscle cells of blood vessels and intramuscular nerve twigs. AT2 was immunolocalized in the smooth muscle cells of blood vessels. These findings suggest that the RAS has a functional role in peripheral nerves and NMJs. ACE and AT1, but AT2 immunoreactivity were increased markedly in dystrophic muscle as compared to controls. ACE and the AT1 were strongly expressed in the cytoplasm and nuclei of regenerating muscle fibers, fibroblasts, and in macrophages infiltrating necrotic fibers. Double immunolabeling revealed that activated fibroblasts in the endomysium and perimysium of DMD and CMD muscle were positive for ACE and AT1. Triple immunolabeling demonstrated that transforming growth factor-beta1 (TGF-beta1) and ACE were colocalized on the cytoplasm of activated fibroblasts in dystrophic muscle. Furthermore, Western blotting showed increases in the expression of AT1 and TGF-beta1 protein in dystrophic muscle, which coincided with our immunohistochemical results. The overexpression of ACE and AT1 in dystrophic muscle would likely result in the increased production of Ang II, which may act on these cells in an autocrine manner via AT1. The activation of AT1 may induce fibrous tissue formation through overexpression of TGF-beta1, which potently activates fibrogenesis and suppresses regeneration. In conclusion, our results imply that the intramuscular RAS-TGF-beta1 pathway is activated in human muscular dystrophy and plays a role at least partly in the pathophysiology of this disease.

GRIN1 mutations cause encephalopathy with infantile-onset epilepsy, and hyperkinetic and stereotyped movement disorders.

Recently, de novo mutations in GRIN1 have been identified in patients with nonsyndromic intellectual disability and epileptic encephalopathy. Whole exome sequencing (WES) analysis of patients with genetically unsolved epileptic encephalopathies identified four patients with GRIN1 mutations, allowing us to investigate the phenotypic spectrum of GRIN1 mutations.

Acute encephalopathy in children with Dravet syndrome

Purpose:  The occurrence of acute encephalopathy in children with Dravet syndrome has been reported sporadically. This study clarified the features of acute encephalopathy in children with Dravet syndrome.

Deletions of SCN1A 5′ genomic region with promoter activity in Dravet syndrome

Mutations involving the voltage‐gated sodium channel αI gene SCN1A are major genetic causes of childhood epileptic disorders, as typified by Dravet syndrome. Here we investigated the upstream regions of the SCN1A 5′ noncoding exons and found two major regions with promoter activity. These two major promoters were simultaneously active in various brain regions and in most neurons. Using multiplex ligation‐dependent probe amplification (MLPA) assays with probes for the 5′ noncoding exons, their upstream regions, and all coding exons of SCN1A, we investigated 130 epileptic patients who did not show any SCN1A mutations by sequence analysis of all coding exons and exon–intron boundaries. Among 71 Dravet syndrome patients, we found two patients with heterozygous microdeletions removing the 5′ noncoding exons and regions with promoter activity but not affecting the coding exons. We also identified four patients with deletions/duplication in the coding region. One patient with symptomatic focal epilepsy also showed a deletion in the coding region. This study provides the first case of microdeletion limited to the SCN1A 5′ promoter region with the coding sequence preserved, and indicates the critical involvement of this upstream region in the molecular pathology of Dravet syndrome. Hum Mutat 31:–11, 2010.

Efficacy of idebenone for respiratory failure in a patient with Leigh syndrome: A long-term follow-up study

Respiratory failure can be the direct cause of death in patients with Leigh syndrome. Unfortunately, no effective treatment strategy is available. Here, we report successful treatment of a patient with Leigh syndrome using idebenone, a derivative of coenzyme Q-10. The patients brainstem function, especially respiratory function, improved after idebenone treatment. Idebenone may be worth trying in patients with Leigh syndrome.

Reduced levels of interleukin-1 receptor antagonist in the cerebrospinal fluid in patients with West syndrome.

We measured the levels of pro- and anti-inflammatory cytokines in the cerebrospinal fluid (CSF) of 24 patients with West syndrome to clarify whether inflammatory cytokines were involved in the pathophysiology of West syndrome. There was no significant elevation of any of the three pro-inflammatory cytokines, interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha, in patients with West syndrome as compared with those in controls. However, level of anti-inflammatory cytokine, IL-1 receptor antagonist was significantly decreased in the CSF of patients with West syndrome. Further study is needed to elucidate whether an immune system disturbance is involved in the pathophysiology of West syndrome.

Utility of subtraction ictal SPECT images in detecting focal leading activity and understanding the pathophysiology of spasms in patients with West syndrome

PURPOSES The aims of the study were to evaluate the detectability of focal leading activity in three cases of West syndrome having focal abnormal activity on EEG by comparing subtraction ictal images and raw ictal images, and to interpret the results in 16 cases. METHODS Subtraction images were constructed using iNeurostat (revision 2). RESULTS In three cases with focal abnormal activity on EEG, subtraction ictal images reflected the EEG findings; in contrast, raw ictal images did not. Diverse degrees of cortical hyperperfusion, ranging from zero to 10 sites, seen in the other 13 cases seemed to reflect spasm pathophysiology and rapid spasm propagation. Subtraction ictal images also allowed the ready detection of hyperperfusion of subcortical structures and of a tight cortico-subcortical relationship in a subset of cases. CONCLUSIONS We showed the superiority of subtraction ictal images in detecting the focal epileptic region and in showing propagation pathways from the cortex to subcortical structures. A subset of spasms in WS may be focal cortical-onset secondarily generalized seizures. We believe that subtraction analysis is valuable in patients with complex WS who have partial seizures and spasms simultaneously along with focal epileptic EEG activity, as they will likely be candidates for epilepsy surgery.

A case surviving for over a year of renal tubular dysgenesis with compound heterozygous angiotensinogen gene mutations

Renal tubular dysgenesis (RTD) is a developmental abnormality of the renal proximal tubules found in patients with Potter syndrome. We report a female newborn with RTD who has survived for more than 18 months. Infusions of fresh frozen plasma (FFP) in the early neonatal period were effective in raising and maintaining her blood pressure. Peritoneal dialysis was required until the appearance of spontaneous urination at 29 days after birth. Histopathological examinations of the kidney revealed dilated renal tubular lumina and foamy columnar epithelial cells in the renal tubules. Endocrinological studies showed a discrepancy between low plasma renin activity (<0.1 ng/ml/hr) and high active renin concentration (135,000 pg/ml), suggesting an aberration in the renin substrate, angiotensinogen. Direct sequencing analysis revealed two novel mutations in the coding region of the angiotensinogen gene (AGT): a nonsense mutation in exon 2 (c.604C > T) and a frameshift deletion at nucleotide 1290 in exon 5 (c.1290delT). The mutations were in the compound heterozygous state, because each parent had each mutation. These findings suggest that angiotensinogen deficiency is one of the causes of RTD. A treatment of the condition with FFP may help to promote long survival.

Complete remission of seizures after corpus callosotomy

OBJECT Corpus callosotomy is usually intended to alleviate-not to achieve total control of-epileptic seizures. A few patients experience complete seizure control after callosotomy, but the associated clinical factors are unknown. The object of this study was to investigate clinical factors associated with long-term seizure remission after total corpus callosotomy in patients with infantile or early childhood onset epilepsy. METHODS Thirteen consecutive patients with infantile or early childhood onset epilepsy underwent 1-stage total corpus callosotomy for alleviation of seizures. Their age at surgery ranged from 1 year and 5 months to 24 years (median 7 years). Eleven patients had West syndrome at the onset of disease, and the other 2 had Lennox-Gastaut syndrome. All patients suffered from spasms, axial tonic seizures, or atonic seizures. Six patients had proven etiology of epilepsy, including tuberous sclerosis, polymicrogyria, trauma, and Smith-Magenis syndrome. The association between postoperative seizure freedom and preoperative factors including age at surgery, no MRI abnormalities, proven etiology, and focal electroencephalographic epileptiform discharges was examined. RESULTS Postoperative seizure freedom was achieved in 4 of 13 patients for a minimum of 12 months. All 4 patients had no MRI abnormalities and no identified etiology. None of the 8 patients with MRI abnormality, 6 patients with known etiology of epilepsy, or 4 patients aged older than 10 years at surgery achieved seizure freedom. Two of the 7 patients with focal electroencephalographic abnormalities became seizure free. Absence of MRI abnormalities was significantly associated with postoperative seizure freedom (p < 0.01). CONCLUSIONS Complete seizure remission is achieved after total corpus callosotomy in a subgroup of patients with intractable epilepsy following West syndrome or Lennox-Gastaut syndrome. One-stage total corpus callosotomy at a young age may provide a higher rate of seizure freedom, especially for patients with no MRI abnormalities and no identified etiology of epilepsy.

Efficacy of sumatriptan in two pediatric cases with abdominal pain-related functional gastrointestinal disorders: does the mechanism overlap that of migraine?

We successfully treated 2 pediatric cases of abdominal pain-related functional gastrointestinal disorder with sumatriptan. When 9 years old, patient 1 developed periodic abdominal pain that was intractable to medication and remitted spontaneously. She was diagnosed with abdominal migraine, categorized as H2c in the Rome III criteria for functional gastrointestinal disorders. At age 12, intranasal sumatriptan relieved her pain, and her attacks halted 2 years later. Patient 2 was a 9-year-old girl diagnosed with attention-deficit hyperactivity disorder (ADHD), who began to have intermittent abdominal pain of variable severity, which sometimes restricted daily activity. She was diagnosed with childhood functional abdominal pain syndrome, categorized as H2d1 using the Rome III criteria. Intranasal sumatriptan also relieved her pain. These cases suggest that the mechanism of pain in abdominal pain-related functional gastrointestinal disorders is similar to that of migraine, with probable central hypersensitivity, at least in a subset of cases.