Decreased oral function in Japanese inpatients with schizophrenia.

AIM: Oral function in patients with schizophrenia has not been well-characterized. To address this, we performed a cross-sectional study of oral function in Japanese inpatients with schizophrenia. METHODS: We measured oral function, including occlusal force, tongue-lip motor function, tongue pressure, and masticatory function in 130 Japanese inpatients with schizophrenia. We then compared the frequency of clinical signs of oral hypofunction among 63 non-elderly and 67 elderly inpatients with schizophrenia, as well as data from 98 elderly control participants from a previous Japanese study. RESULTS: The frequency of reduced occlusal force was significantly higher in the elderly inpatients (76.2%) than in the non-elderly inpatients (43.9%) and elderly controls (43.9%). The frequency of decreased tongue-lip motor function in non-elderly inpatients (96.8%) and elderly inpatients (97.0%) was significantly higher than that in elderly controls (56.1%). The frequency of decreased tongue pressure in non-elderly inpatients (66.1%) and elderly inpatients (80.7%) was significantly higher than that in elderly controls (43.9%). Finally, the frequency of decreased masticatory function was highest in elderly inpatients (76.5%), followed by non-elderly inpatients (54.8%) and elderly controls (15.3%). CONCLUSION: Oral function was decreased in both non-elderly and elderly Japanese inpatients with schizophrenia compared with elderly controls.

Modeling of multiple atrial septal defects with inferior vena cava rim deficiency: Three-dimensional visualization of the rim based on transthoracic echocardiographic imaging.

The morphologic features of the multiple atrial septal defects assessed by TTE-based 3D imaging were similar to those by 3D-TEE. TTE-based 3D model had excellent visibility, allowing observation of 3D structure of the rims of the defects. It may be useful method for assessment of the multiple atrial septal defects.

Replacement of pulmonary venous stent during Fontan operation.

Post-operative pulmonary venous stenosis is a poor prognostic factor in single-ventricle haemodynamics. Implantation of a drug-eluting stent is a therapeutic option. However, due to their small size, they inevitably become inadequate as the patient grows. We present the first case, to the best of our knowledge, of the replacement of a small-diameter stent with a large-diameter stent during Fontan surgery.

Site-Selective Incorporation of a Functional Group into Lys175 in the Vicinity of the Active Site of Chymotrypsin by Using Peptidyl α-Aminoalkylphosphonate Diphenyl Ester-Derivatives.

We previously reported that Lys175 in the region of the active site of chymotrypsin (Csin) could be site-selectively modified by using an N-hydroxy succinimide (NHS) ester of the peptidyl derivative containing 1-amino-2-ethylphenylphosphonate diphenyl ester [NHS-Suc-Ala-Ala-PheP(OPh)2]. In this study, the Lys175-selective modification method was expanded to incorporate functional groups into Lys 175 in Csin. Two types of peptidyl phosphonate derivatives with the dansyl group (Dan) as a functional molecule, Dan-ß-Ala-[Asp(NHS) or Glu(NHS)]-Ala-Ala-(R)-PheP(OPh)2 (DanD and DanE, respectively), were synthesized, and their action was evaluated when modifying Lys175 in Csin. Ion-exchange chromatography (IEC), fluorescence spectroscopy, and LC-MS/MS were used to analyze the products from the reaction of Csin with DanD or DanE. By IEC and LC-MS/MS, the results showed that DanE reacted with Csin more effectively than DanD to produce the modified Csin (DanMCsin) bearing Dan at Lys175. DanMCsin exhibited an enzymatic activity corresponding to 1/120 of Csin against Suc-Ala-Ala-Phe-pNA. In addition, an effect of Lys175 modification on the access of the proteinaceous Bowman-Birk inhibitor to the active site of DanMCsin was investigated. In conclusion, by using a peptidyl derivative containing 1-amino-2-ethylphenylphosphonate diphenyl ester, we demonstrated that a functional group could be incorporated into Lys175 in Csin.

Complex congenital cardiovascular anomaly in a patient with AGO1-associated disorder.

Pathogenic AGO1 variants have been associated with neurodevelopmental disorders, including autism spectrum disorder, developmental delay, intellectual disability, and dysmorphic facial appearance. In mammalian models, defects in microRNA (miRNA) biogenesis are associated with congenital heart disease and dilated cardiomyopathy. We describe the case of a patient with partial anomalous pulmonary venous return, hypoplastic left lung, bilateral pulmonary sequestration, and dilated myocardiopathy. We identified a de novo pathogenic variant of AGO1, which encodes an Argonaute protein forming a gene-silencing complex with microRNAs. The patient was diagnosed with dilated cardiomyopathy with no apparent cause at 3 years of age. She was started on enalapril and carvedilol, and her heart failure was well controlled. We expanded the AGO1-associated phenotype to include complex congenital cardiovascular anomaly and dilated cardiomyopathy in humans.

Cardiac features of Noonan syndrome in Japanese patients.

BACKGROUND: Cardiovascular disease is one of the most important problems in long-term follow-up for Noonan syndrome. We examined cardiovascular issues and clinical manifestations, with a focus on the cardiovascular disease and prognosis of patients with Noonan syndrome. METHODS: This single-centre study evaluated patients who were clinically and genetically diagnosed with Noonan syndrome. RESULTS: Forty-three patients diagnosed with Noonan syndrome were analysed. The most prevalent responsible mutation was found in PTPN11 (25/43). The second and third most prevalent causative genes were SOS1 (6/43) and RIT1 (5/43), respectively, and 67.4% of genetically diagnosed patients with Noonan syndrome had structural cardiovascular abnormalities. Pulmonary valve stenosis was prevalent in patients with mutations in PTPN11 (8/25), SOS1 (4/6), and RIT1 (4/5). Hypertrophic cardiomyopathy was found in two of three patients with mutations in RAF1. There was no difference in the cardiovascular events or cardiovascular disease prevalence in patients with or without PTPN11 mutations. The proportion of RIT1 mutation-positive patients who underwent intervention due to cardiovascular disease was significantly higher than that of patients with PTPN11 mutations. Patients who underwent any intervention for pulmonary valve stenosis exhibited significantly higher pulmonary flow velocity than patients who did not undergo intervention, when they visited our hospital for the first time. All patients who underwent intervention for pulmonary valve stenosis had a pulmonary flow velocity of more than 3.0 m/s at first visit. CONCLUSIONS: These findings suggest that genetic information can provide a clinical prognosis for cardiovascular disease and may be part of genotype-based follow-up in Noonan syndrome.

Electrocardiographic Changes with Age in Japanese Patients with Noonan Syndrome.

Little information is available on age-related electrocardiographic changes in patients with Noonan syndrome. This single-center study evaluated the electrocardiograms of patients with Noonan syndrome. We divided the patients (n = 112; electrocardiograms, 256) into four groups according to age: G1 (1 month-1 year), G2 (1-6 years), G3 (6-12 years), and G4 (>12 years). Typical Noonan syndrome-related electrocardiographic features such as left-axis deviation, abnormal Q wave, wide QRS complex, and small R wave in precordial leads were detected. A high percentage of QRS axis abnormalities was found in all groups. Significant differences in right-axis deviation (RAD) were noted among the groups: 56.5% of G1 patients showed RAD compared with 33.3% of G2, 21.1% of G3, and 19.2% of G4 patients. The small R was also significantly different among the groups: 32.6% of G1 patients showed a small R wave compared with 14.9% of G2, 8.5% of G3, and 15.4% of G4 patients. Of the 53 patients with Noonan syndrome aged 1 month to 2 years, 18 had T-positive V1 with a higher prevalence of pulmonary stenosis and cardiac interventions. QRS axis abnormalities, small R in V6, and T-positive V1 could help diagnose Noonan syndrome in infants or young children.

Single-crystal structure refinements and Debye temperatures of Ir2S3 kashinite and Rh2S3 bowieite.

Single crystals of Ir2S3 (diiridium trisulfide) and Rh2S3 (dirhodium trisulfide) were grown in evacuated silica-glass tubes using a chemical transport method and their crystal structures were determined by single-crystal X-ray diffraction analysis. These compounds have a unique sesquisulfide structure in which pairs of face-sharing octahedra are linked into a three-dimensional structure by further edge- and vertex-sharing. Ir2S3 and Rh2S3 had similar unit-cell parameters and bond distances. The atomic displacement parameter (MSD: mean-square displacement) of each atom in Ir2S3 was considerably smaller than that in Rh2S3. The Debye temperatures (ΘD) estimated from the observed MSDs for the Ir, S1 and S2 sites in Ir2S3 were 259, 576 and 546 K, respectively, and those for Rh, S1 and S2 in Rh2S3 were 337, 533 and 530 K, respectively. The bulk Debye temperature for Ir2S3 kashinite (576 K) was found to rank among the higher values reported for many known sulfides. The bulk Debye temperature for Rh2S3 bowieite (533 K) was lower than that for Ir2S3 kashinite, which crystallizes in the early sequences of mineral crystallization differentiation from the primitive magma in the Earth's mantle.

Association Between the Number of Remaining Teeth and Body Mass Index in Japanese Inpatients with Schizophrenia.

Purpose: There is little evidence regarding the effects of dental status on body mass index (BMI) in inpatients with schizophrenia. Thus, we performed a cross-sectional study to explore the associations between the number of remaining teeth and BMI in Japanese inpatients with schizophrenia. Patients and Methods: We performed multiple regression analysis to assess the effects of potential predictors (age, sex, number of remaining teeth, number of antipsychotics prescribed, chlorpromazine equivalent dose, and antipsychotic type) on BMI in 212 inpatients with schizophrenia. We then compared the number of remaining teeth between inpatients with schizophrenia and the Japanese general population (3283 individuals) from the Japan Dental Diseases Survey 2016, using an analysis of covariance with age and sex as covariates. Results: Multiple regression analysis showed that the number of remaining teeth and the number of antipsychotics prescribed were significantly correlated with BMI (standardized regression coefficient = 0.201 and 0.235, respectively). In the analysis of covariance, inpatients with schizophrenia had significantly fewer remaining teeth compared with the Japanese general population (mean 14.8 [standard deviation: 10.9] vs mean 23.0 [standard deviation: 8.1]). Conclusion: These results suggested that tooth loss and antipsychotic polypharmacy affect BMI in inpatients with schizophrenia, and that inpatients with schizophrenia lose more teeth compared with the general population.

Anatomical variations of the canine adrenal vessels.

The canine adrenal glands receive blood from the celiac artery, cranial mesenteric artery, caudal phrenic artery, cranial abdominal artery, phrenicoabdominal trunk, abdominal aorta, renal artery and lumbar artery. These are classified into three types: cranial, middle and caudal adrenal branches. It is also known that the adrenal vein flows into the phrenicoabdominal vein. However, individual differences in the branching pattern of adrenal vessels have not been systematically analysed. We evaluated adrenal vessels in dogs that underwent contrast-enhanced abdominal computed tomography (CT). There were 255 arteries travelling to the adrenal glands in 47 cases, with 1-6 arteries travelling per adrenal gland. The arteries included 67 caudal phrenic arteries, 62 aortic arteries, 60 cranial abdominal arteries, 39 renal arteries, 12 phrenicoabdominal trunks, 8 cranial mesenteric arteries, 6 celiac arteries and 1 lumbar artery. Most of the branches were from the aorta and caudal phrenic artery on the left side, and the cranial abdominal and caudal phrenic artery on the right side. A total of 110 adrenal veins were identified. Inflow into the phrenicoabdominal vein and into the right and left renal veins was observed, and we identified no inflow into other veins. This study demonstrated two points: laterality and individual differences in adrenal blood vessels. When evaluating adrenal blood vessels with abdominal contrast-enhanced CT, it is recommended to take images under general anaesthesia with breath-holding and observe them using multiplanar reconstruction.

Assessment of the left ventricular volume of tetralogy of Fallot by electrocardiogram.

BACKGROUND: Sufficient left ventricular volume is required for patients with tetralogy of Fallot (TOF) who are going to have biventricular repair. In this study, we investigated the utility of the electrocardiogram to evaluate left ventricular volume in patients with TOF. METHOD: Patients whose left ventricular (LV) end-diastolic volume was lower than 80% of normal were defined as having a small LV. Seven patients with TOF who had to undergo Blalock-Taussig shunt surgery because of a small LV were assigned to group S. Twenty patients with TOF who had sufficient LV volume were assigned to group G. The amplitudes of the Q wave of V5-7 leads (QV5-QV7), the S wave of V1 lead, and the R wave of the II, III, aVf, and V5-7 leads of the electrocardiogram were evaluated. RESULTS: The amplitude of QV5 was 0 mV in all cases in group S, which was significantly smaller than that in group G (0 vs 0.01 mV, P = 0.028). The frequency of absent QV5 was significantly higher in group S than in group G (100% vs 50%, P = 0.026). Absent QV5 showed 100% sensitivity, 50% specificity, and a negative predictive value of 100% for a small LV. CONCLUSIONS: In TOF, the amplitude of the septal Q wave reflects LV volume. In particular, the absence of QV5 suggests a small LV end-diastolic volume, which is lower than 80% of normal.

Takotsubo cardiomyopathy in a child with single-ventricle disease.

Takotsubo cardiomyopathy, a disease that causes transient contractile abnormalities mainly in the left ventricular apex, is rarely reported in children, especially in those with single-ventricle disease. A 4-year-old boy with a single right ventricle was transferred to our hospital following a severe seizure and was diagnosed with takotsubo cardiomyopathy by echocardiography. His cardiac function improved; however, he developed hypoxic-ischemic encephalopathy.

Antemortem diagnosis of anomalous origin of the left coronary artery from the pulmonary artery in a dog.

BACKGROUND: In both humans and animals, anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital coronary artery anomaly. In veterinary medicine, ALCAPA is reported to be discovered only during autopsy or necropsy, and diagnostic methods and prognosis remain poorly understood in dogs. CASE PRESENTATION: A 6-month-old Kaninchen Dachshund was diagnosed with functional mitral valve regurgitation and ALCAPA. Echocardiography identified anomalous vessels in the left ventricular wall and abnormal origin of the left coronary artery from the pulmonary artery. Further evaluation with coronary computed tomographic angiography demonstrated the left coronary artery arising from the posterior aspect of the main pulmonary artery together with the characteristic findings of ALCAPA. The right coronary artery was found to be dilated and tortuous. Furthermore, dilated coronary collateral arteries within the ventricular septum and along the epicardial surface were observed. The dog underwent surgery, but the origin of the anomalous artery could not be ligated, and it died from pulmonary edema 5 months after surgery. CONCLUSION: Anomalous origin of the left coronary artery from the pulmonary artery is overlooked in clinical practice due to its rarity. Coronary computed tomographic angiography was useful to definitively diagnose ALCAPA in a low-invasive manner. Antemortem diagnosis of ALCAPA was shown to be possible in dogs for the first time, and presence of unexplained mitral valve regurgitation should raise concern to this anomaly.

Cardiac Resynchronization Therapy Using Single Site Left Ventricular Pacing in a Tricuspid Atresia Patient With Left Bundle Branch Block.

Cardiac resynchronization therapy (CRT) is typically achieved by pacing both ventricles. However, left ventricular-only pacing has been shown to be noninferior to biventricular pacing in patients with left bundle branch block and normal atrioventricular conduction. However, there is no evidence in favour of CRT with single-site pacing for patients with single-ventricle physiology. In this case, we performed CRT with single-site pacing in a patient with tricuspid atresia and left bundle branch block, enabling successful Fontan completion.

La thérapie de resynchronisation cardiaque (TRC) consiste généralement en une stimulation des deux ventricules. Il a toutefois été montré que la stimulation du ventricule gauche seulement n'est pas inférieure à la stimulation biventriculaire chez les patients présentant un bloc de branche gauche et une conduction auriculoventriculaire normale. Cependant, aucune donnée probante n'appuie la TRC par stimulation d'une seule cavité cardiaque dans le cas d'un cœur univentriculaire. Dans le cas que nous présentons, nous avons eu recours à la TRC par stimulation d'une seule cavité cardiaque chez une patiente présentant une atrésie tricuspidienne et un bloc de branche gauche, ce qui a permis de réaliser l'intervention de Fontan.

A retrospective study of perioperative clinical seizures and epilepsy in children after operation for CHD.

This study investigated the incidence and risk factors of perioperative clinical seizure and epilepsy in children after operation for CHD. We included 777 consecutive children who underwent operation from January 2013 to December 2016 at Kanagawa Children's Medical Center, Kanagawa, Japan. Perinatal, perioperative, and follow-up medical data were collected. Elastic net regression and mediation analysis were performed to investigate risk factors of perioperative clinical seizure and epilepsy. Anatomic CHD classification was performed based on the preoperative echocardiograms; cardiac surgery was evaluated using Risk Adjustment in Congenital Heart Surgery 1. Twenty-three (3.0%) and 15 (1.9%) patients experienced perioperative clinical seizure and epilepsy, respectively. Partial regression coefficient with epilepsy as the objective variable for anatomical CHD classification, Risk Adjustment in Congenital Heart Surgery 1, and the number of surgeries was 0.367, 0.014, and 0.142, respectively. The proportion of indirect effects on epilepsy via perioperative clinical seizure was 22.0, 21.0, and 33.0%, respectively. The 15 patients with epilepsy included eight cases with cerebral infarction, two cases with cerebral haemorrhage, and three cases with hypoxic-ischaemic encephalopathy; white matter integrity was not found. Anatomical complexity of CHD, high-risk cardiac surgery, and multiple cardiac surgeries were identified as potential risk factors for developing epilepsy, with a low rate of indirect involvement via perioperative clinical seizure and a high rate of direct involvement independently of perioperative clinical seizure. Unlike white matter integrity, stroke and hypoxic-ischaemic encephalopathy were identified as potential factors for developing epilepsy.

Influence of Atomoxetine on Relationship Between ADHD Symptoms and Prefrontal Cortex Activity During Task Execution in Adult Patients.

Objective: We conducted this non-randomized prospective interventional study to clarify the relationship between improved attention-deficit hyperactivity disorder (ADHD) symptoms and regional brain activity. Methods: Thirty-one adult patients underwent near-infrared spectroscopy examinations during a go/no-go task, both before and 8 weeks after atomoxetine administration. Results: Clinical symptoms, neuropsychological results of the go/no-go task, and bilateral lateral prefrontal activity significantly changed. A positive correlation was observed between right dorsolateral prefrontal cortex activity and Conners' Adult ADHD Rating Scales scores. Before atomoxetine administration, no correlations between prefrontal cortex activity and clinical symptoms were observed in all cases. When participants were divided into atomoxetine-responder and non-responder groups, a positive correlation was observed between prefrontal cortex activity and clinical symptoms in the non-responder group before treatment but not in the responder group, suggesting that non-responders can activate the prefrontal cortex without atomoxetine. Conclusions: Individuals with increased ADHD symptoms appear to recruit the right dorsolateral prefrontal cortex more strongly to perform the same task than those with fewer symptoms. In clinical settings, individuals with severe symptoms are often observed to perform more difficultly when performing the tasks which individuals with mild symptoms can perform easily. The atomoxetine-responder group was unable to properly activate the right dorsolateral prefrontal cortex when necessary, and the oral administration of atomoxetine enabled these patients to activate this region. In brain imaging studies of heterogeneous syndromes such as ADHD, the analytical strategy used in this study, involving drug-responsivity grouping, may effectively increase the signal-to-noise ratio.

Correlation of exercise-induced peripheral venous hypertension with exercise intolerance in patients with Fontan circulation.

Owing to the absence of a sub-pulmonary ventricle, the central venous pressure rises in patients with Fontan circulation. During exercise, central venous pressure may rise further to increase the systemic ventricular preload and cardiac output. We performed a single-centre prospective trial of cardiopulmonary exercise test while monitoring peripheral venous pressure which strongly correlates with central venous pressure. The objective of this study was to test the hypothesis that peripheral venous pressure at peak exercise inversely correlates with exercise capacity in patients with Fontan circulation. Seventeen patients following Fontan operation performed cardiopulmonary exercise test while monitoring peripheral venous pressure. Peak oxygen uptake, heart rate reserve, peak oxygen pulse (divided by body surface area), and peripheral venous pressure at peak exercise were measured. Correlations of peripheral venous pressure at peak exercise with the peak oxygen uptake, heart rate reserve, and peak oxygen pulse were evaluated. The peripheral venous pressure at peak exercise inversely correlated with the peak oxygen uptake (R = -0.66, p < 0.01), heart rate reserve (R = -0.6, p < 0.05), and peak oxygen pulse (R = -0.48, p < 0.05). Exercise-induced peripheral venous hypertension correlates with exercise intolerance in patients with Fontan circulation. Peak oxygen uptake is a useful index for evaluating the status of congestion in the daily life of patients with Fontan circulation.

Validation of Self-Monitoring Devices Supporting Sodium Intake Reduction: An Experimental Feeding Study Using Standardized Low-Salt and High-Salt Meals among Healthy Japanese Volunteers.

INTRODUCTION: Although several approaches for approximating daily Na intake and the Na/K ratio using casual urine are available, the most useful method remains unclear during daily practice and at home. METHODS: Twenty-seven participants measured their casual urinary Na/K ratio repeatedly using a Na/K ratio monitor and also measured overnight urine once daily using a monitoring device which delivers on-site feedback to estimate their salt intake under unrestricted, low-salt (LS) (6 g/day), and high-salt (HS) (12 g/day) diets. RESULTS: The monitoring method utilizing overnight urine to estimate daily Na remained insensitive, resulting in significant overestimation during the LS diet and underestimation during the HS diet periods; estimated salt intake during the LS and HS diet periods plateaued at 7-8 g/day and 9-10 g/day within 3 day; mean estimated salt intake was 11.3 g/day, 7.9 g/day, and 9.8 g/day on the last day of the unrestricted, LS, and HS diets; the coefficient of variation (CV) of the estimated Na intake was 0.23 and 0.17 in the latter half of the low- and high-salt diet periods, respectively. The mean urinary Na/K molar ratio was 5.6, 2.5, and 5.3 on the last day of the unrestricted, LS, and HS diets; the CV of the daily mean Na/K ratio was 0.41 and 0.36 in the latter half of the LS and HS diet periods, respectively. The urinary Na/K ratio during the LS and HS diet periods plateaued within 2 days. The monitoring method based on the daily mean of the casual urinary Na/K ratio reflected the actual change in Na intake, and the estimated value tracked the actual changes in salt intake with smaller difference than the overnight urine estimates when using the estimation coefficient set at 2; estimated salt intake during the LS and HS diet periods plateaued at 5-6 g/day and 10-12 g/day within 2-3 day; mean estimated salt intake was 11.0 g/day, 5.7 g/day, and 10.7 g/day on the last day of the unrestricted, LS, and HS diets, respectively. DISCUSSION/CONCLUSION: Estimates of daily Na intake derived from overnight urine may remain insensitive during dietary interventions. The urinary Na/K ratio reflects the actual change in Na intake during dietary modification and may serve as a practical marker, particularly during short-term interventions. Conversion from the urinary Na/K ratio to estimated salt intake may be useful, if the coefficient was set appropriate by further investigations.

The lowest effective plasma concentration of atomoxetine in pediatric patients with attention deficit/hyperactivity disorder: A non-randomized prospective interventional study.

BACKGROUND: Atomoxetine (ATX) is used as a first-line, non-stimulant treatment for attention-deficit/hyperactivity disorder (ADHD), although no studies have systematically examined the relationship between plasma concentration and clinical efficacy. We conducted this non-randomized prospective interventional study to examine the relationship between plasma concentration of ATX and clinical efficacy. METHODS: Forty-three ADHD pediatric patients received ATX, and the steady-state through plasma concentration of the last daily dose that was maintained for at least 4 weeks were determined by high-performance liquid chromatography. RESULTS: The receiver operating characteristic curve suggested that when plasma concentration exceeded 64.60 ng/mL, scores on the ADHD-Rating Scale improved by 50% or more (P = .14). Although 6 of the 8 final responders were unresponsive at the initial dose (.72 ±â€Š.04 mg/kg [mean ±â€Šstandard deviation]), they responded after increasing the ATX dose to the final dose (1.52 ±â€Š.31 mg/kg). Excluding 7 outlier participants, the concentration was 83.3 ±â€Š32.3 ng/mL in 7 responders and was significantly higher than 29.5 ±â€Š23.9 ng/mL (P < .01) for the 29 non-responders. CONCLUSIONS: These results suggest that a minimum effective plasma concentration of ATX is required to achieve sufficient clinical efficacy. We hypothesized a mechanism that results in the realization of a clinical effect when the plasma concentration exceeds a certain threshold in the potential response group, whereas will not improve even if the plasma concentration is increased in the unqualified non-responder group.

A Metal-Free, Disulfide Oxidized Form of Superoxide Dismutase 1 as a Primary Misfolded Species with Prion-Like Properties in the Extracellular Environments Surrounding Motor Neuron-Like Cells.

Superoxide dismutase 1 (SOD1) is a metalloenzyme with high structural stability, but a lack of Cu and Zn ions decreases its stability and enhances the likelihood of misfolding, which is a pathological hallmark of amyotrophic lateral sclerosis (ALS). A growing body of evidence has demonstrated that misfolded SOD1 has prion-like properties such as transmissibility between cells and intracellular propagation of misfolding of natively folded SOD1. Recently, we found that SOD1 is misfolded in the cerebrospinal fluid of sporadic ALS patients, providing a route by which misfolded SOD1 spreads via the extracellular environment of the central nervous system. Unlike intracellular misfolded SOD1, it is unknown which extracellular misfolded species is most relevant to prion-like properties. Here, we determined a conformational feature of extracellular misfolded SOD1 that is linked to prion-like properties. Using culture media from motor neuron-like cells, NSC-34, extracellular misfolded wild-type, and four ALS-causing SOD1 mutants were characterized as a metal-free, disulfide oxidized form of SOD1 (apo-SOD1S-S). Extracellular misfolded apo-SOD1S-S exhibited cell-to-cell transmission from the culture medium to recipient cells as well as intracellular propagation of SOD1 misfolding in recipient cells. Furthermore, culture medium containing misfolded apo-SOD1S-S exerted cytotoxicity to motor neuron-like cells, which was blocked by removal of misfolded apo-SOD1S-S from the medium. We conclude that misfolded apo-SOD1S-S is a primary extracellular species that is linked to prion-like properties.