X-linked Myotubular Myopathy Manifesting Carrier with Central and Peripheral Nervous System Involvement.

X-linked myotubular myopathy (XLMTM) is a rare genetic disorder caused by X-linked mutations in the MTM1 gene. Although heterozygous females are typically asymptomatic, affected cases have recently been reported. We herein report a case of XLMTM manifesting carrier of the pathogenic c.206dupG mutation in MTM1 with uncommon extramuscular symptoms. She developed gaze nystagmus and cognitive impairment in addition to muscle weakness. Electrophysiological studies and brain magnetic resonance imaging indicated the involvement of the central and peripheral nervous systems. XLMTM manifesting carriers may have a wider spectrum of clinical phenotypes than currently assumed. Appropriate follow-up of extramuscular and conventional muscular manifestations is important in such cases.

Efficacy of Computed Tomography-Based Evaluation of Myocardial Extracellular Volume Combined With Red Flags for Early Screening of Concealed Cardiac Amyloidosis in Patients With Atrial Fibrillation.

BACKGROUND: The prevalence of transthyretin amyloid cardiomyopathy (ATTR-CM) in atrial fibrillation (AF) patients remains unclear. We explored the efficacy of computed tomography-based myocardial extracellular volume (CT-ECV) combined with red flags for the early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.Methods and Results: Patients referred for AF ablation at Oita University Hospital were prescreened using the red-flag signs defined by echocardiographic or electrocardiographic findings, medical history, symptoms, and blood biochemical findings. Myocardial CT-ECV was quantified in red flag-positive patients using routine pre-AF ablation planning cardiac CT with the addition of delayed-phase cardiac CT scans. Patients with high (>35%) ECV were evaluated using technetium pyrophosphate (99 mTc-PYP) scintigraphy. A cardiac biopsy was performed during the planned AF ablation procedure if 99 mTc-PYP scintigraphy was positive. Between June 2022 and June 2023, 342 patients were referred for AF ablation. Sixty-seven (19.6%) patients had at least one of the red-flag signs. Myocardial CT-ECV was evaluated in 57 patients because of contraindications to contrast media, revealing that 16 patients had high CT-ECV. Of these, 6 patients showed a positive 99 mTc-PYP study, and 6 patients were subsequently diagnosed with wild-type ATTR-CM via cardiac biopsy and genetic testing. CONCLUSIONS: CT-ECV combined with red flags could contribute to the systematic early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.

Objectively measured prolonged sleep is associated with plasma cytokines in older adults with mild cognitive impairment.

This study aimed to determine whether objective sleep time is associated with the concentrations of various plasma cytokines in older adults with mild cognitive impairment (MCI). In total, 118 adults with MCI (66 women; mean age: 75.7 years) participated in this prospective cohort study. All participants were required to wear a wristband sensor for 7.8 days, on average, every 3 months for 1 year and undergo measurement of 27 plasma cytokines using multiplex immunoassays. After adjusting for potential confounders, the associations of total sleep time with cytokine concentrations were assessed by multiple linear regression analysis. The total sleep time was significantly correlated with plasma interleukin (IL)-9 and macrophage inflammatory protein (MIP)-1ß levels (r = 0.239, p = 0.009, and r = 0.242, p = 0.008, respectively). Moreover, these associations remained significant after adjusting for covariates, including demographic characteristics, lifestyle-related diseases, and apolipoprotein E status (ß = 0.272, 95% confidence interval: 0.095-0.448, p = 0.003, and ß = 0.27, 95% confidence interval: 0.092-0.449, p = 0.003, respectively). Thus, this study is the first to demonstrate the association between objective prolonged sleep and higher plasma IL-9 and MIP-1ß levels in older adults with MCI.

Correlation between a commercial electrophysiological test of sudomotor function and intraepidermal nerve fiber density in hereditary transthyretin amyloidosis.

INTRODUCTION/AIMS: In the early stage, hereditary transthyretin (ATTRv) amyloidosis predominantly affects small nerve fibers, resulting in autonomic dysfunction and impaired sensation of pain and temperature. Evaluation of small fiber neuropathy (SFN) is therefore important for early diagnosis and treatment of ATTRv amyloidosis. Herein, we aimed to investigate the accuracy of a quick and non-invasive commercial sudomotor function test (SFT) for the assessment of SFN in ATTRv amyloidosis. METHODS: We performed the SFT in 39 Japanese adults with ATTRv amyloidosis, and we analyzed the correlations between electrochemical skin conductance (ESC) values obtained via the SFT and the parameters of other neuropathy assessment methods. RESULTS: ESC in the feet demonstrated significant, moderate correlations with intraepidermal nerve fiber density (IENFD) results (Spearman's rank correlation coefficient [rs ], 0.58; p < .002) and other neuropathy assessment methods including the sensory nerve action potential amplitude in the nerve conduction studies (rs , 0.52; p < .001), the Neuropathy Impairment Score (rs , -0.45; p < .01), the heat-pain detection threshold (rs , -0.62; p < .0001), and the autonomic section of the Kumamoto ATTRv clinical score (rs , -0.53; p < .0001). DISCUSSION: In this study, we found that ESC values in the feet via the SFT demonstrated significant, moderate correlations with IENFD and other SFN assessment methods in patients with ATTRv amyloidosis, suggesting that the SFT appears to be an appropriate method for assessment of SFN in this disease.

Predicting positron emission tomography brain amyloid positivity using interpretable machine learning models with wearable sensor data and lifestyle factors.

BACKGROUND: Developing a screening method for identifying individuals at higher risk of elevated brain amyloid burden is important to reduce costs and burden to patients in clinical trials on Alzheimer's disease or the clinical setting. We developed machine learning models using objectively measured lifestyle factors to predict elevated brain amyloid burden on positron emission tomography. METHODS: Our prospective cohort study of non-demented, community-dwelling older adults aged ≥ 65 years was conducted from August 2015 to September 2019 in Usuki, Oita Prefecture, Japan. One hundred and twenty-two individuals with mild cognitive impairment or subjective memory complaints (54 men and 68 women, median age: 75.50 years) wore wearable sensors and completed self-reported questionnaires, cognitive test, and positron emission tomography imaging at baseline. Moreover, 99 individuals in the second year and 61 individuals in the third year were followed up. In total, 282 eligible records with valid wearable sensors, cognitive test results, and amyloid imaging and data on demographic characteristics, living environments, and health behaviors were used in the machine learning models. Amyloid positivity was defined as a standardized uptake value ratio of ≥ 1.4. Models were constructed using kernel support vector machine, Elastic Net, and logistic regression for predicting amyloid positivity. The mean score among 10 times fivefold cross-validation repeats was utilized for evaluation. RESULTS: In Elastic Net, the mean area under the receiver operating characteristic curve of the model using objectively measured lifestyle factors alone was 0.70, whereas that of the models using wearable sensors in combination with demographic characteristics and health and life environment questionnaires was 0.79. Moreover, 22 variables were common to all machine learning models. CONCLUSION: Our machine learning models are useful for predicting elevated brain amyloid burden using readily-available and noninvasive variables without the need to visit a hospital. TRIAL REGISTRATION: This prospective study was conducted in accordance with the Declaration of Helsinki and was approved by the local ethics committee of Oita University Hospital (UMIN000017442). A written informed consent was obtained from all participants. This research was performed based on the Strengthening the Reporting of Observational Studies in Epidemiology reporting guideline.

Objective sleep was longitudinally associated with brain amyloid burden in mild cognitive impairment.

OBJECTIVE: Understanding the longitudinal association of objective sleep and physical activity with brain amyloid burden and cortical glucose metabolism has critical clinical and public health implications for dementia prevention in later life. METHODS: We enrolled 118 individuals aged ≥65 years with mild cognitive impairment, who were followed up on from August 2015 to September 2019. All participants continuously wore an accelerometer sensor for 7 consecutive days every 3 months and received annual 11 C-Pittsburgh compound-B and 18 F-fluorodeoxyglucose positron emission tomography (PET). Sleep and physical activity parameters were assessed using accelerometer sensor data and PET imaging was quantified using a standardized uptake-value ratio. Fifty-seven participants (48.3%) completed a lifestyle factor assessment and PET imaging over the 3-year period. A linear mixed-effects model was applied to examine the longitudinal association of sleep and physical activity parameters with PET imaging over the 3-year period, controlling for potential confounders. RESULTS: Sleep efficiency was inversely associated with amyloid uptake in the frontal lobe. Although sleep duration was positively associated with global amyloid uptake, particularly in the frontal lobe, their impact was extremely small. However, physical activity parameters were not significantly associated with the 11 C-Pittsburgh compound-B-uptake. Furthermore, sleep and physical activity parameters were not significantly associated with cortical glucose metabolism. INTERPRETATION: Lower sleep efficiency could be an early symptom of greater brain amyloid burden at the mild cognitive impairment stage. Therefore, the assessment of sleep may be useful for identifying individuals at higher risk for brain amyloid burden. Future longer term observational studies are required to confirm these findings.

Lifestyle factors that affect cognitive function-a longitudinal objective analysis.

Background: Identifying lifestyle factors associated with cognitive decline has critical clinical and public health implications for dementia prevention in later life. The longitudinal associations of sleep and physical activity with cognitive function remain unclear. This study examined whether objectively measured sleep and physical activity were longitudinally associated with cognitive function in older adults over a three-year period. Methods: This prospective cohort study enrolled 855 community-dwelling adults aged 65 and older, who were followed from 2015 to 2019. All participants were required to wear a wearable sensor for 7 consecutive days every 3 months and had annual cognitive assessments. Wearable sensor data (August 2015-September 2019) and Mini-Mental State Examination (MMSE) scores (August 2015-April 2019) were collected over 3 years of follow-up. First, principal component analysis was conducted to reduce the dimensions of the sleep and physical activity variables to two principal components for inclusion in a mixed-effects model. The sleep index consisted of sleep efficiency, time awake after sleep onset, and waking frequency. The physical activity index was composed of walking comprised steps per day and time devoted to light or moderate-to-vigorous physical activity. A higher sleep index indicated poor sleep quality, whereas a lower physical activity index indicated less physical activity. Second, a linear mixed effect model was used to examine the longitudinal association of sleep and physical activity indices with cognitive decline over time. Results: In total, 855 adults were recruited for this study at baseline. Of these, 729 adults (85.3%) completed a measurement of lifestyle factors and an annual cognitive testing, whereas 126 were excluded because of death or loss during follow-up. After adjusting for age, sex, education level, and time, the sleep index was inversely associated with MMSE scores (estimate, -0.06229; standard error, 0.02202; p = 0.0047) and the physical activity index was positively associated with MMSE scores (estimate, 0.06699; standard error, 0.03343; p = 0.0453). Conclusion: Poor sleep quality and lower physical activity were significant risk factors for subsequent cognitive decline in older adults. The present study facilitates the development of novel evidence-based interventions for physical activity and sleep quality to delay cognitive decline.

Comparison of Brain Amyloid Deposition and Cortical Glucose Metabolism Between Clinic- and Community-Based Cohort.

BACKGROUND: The differences in positron emission tomography (PET) imaging among older adults with mild cognitive impairment (MCI), according to the recruitment source, remain unclear. OBJECTIVE: To investigate the differences in brain amyloid deposition and cortical glucose metabolism according to recruitment source among older adults with MCI. METHODS: Participants in the clinic-based MCI cohort, who were referred to Oita University Hospital for cognitive decline, consisted of 90 adults with MCI. The community-based MCI cohort, which participated in a prospective cohort study, consisted of 118 adults with MCI. Participants underwent cognitive function evaluation, 11C-Pittsburgh compound B (PiB)-PET, and 18F-fluorodeoxyglucose (FDG)-PET. The prevalence of amyloid positivity and mean PiB and FDG uptake values were compared between the cohorts. Moreover, a voxel-by-voxel group study was performed to determine the areas with significant differences between the clinic- and community-based MCI cohorts. RESULTS: The prevalence of amyloid positivity and mean PiB uptake value in the clinic-based MCI cohort were significantly higher than those in the community-based MCI cohort (p < 0.001 and p < 0.001, respectively). The mean FDG uptake value in the clinic-based MCI cohort was significantly lower than that in the community-based MCI cohort (p < 0.001). SPM 8 analysis showed significantly increased PiB uptake in the precuneus and parietotemporal lobe and significantly decreased FDG uptake in the posterior cingulate in the clinic-based MCI cohort compared to the community-based MCI cohort. CONCLUSION: The prevalence and severity of amyloid pathology in older adults with MCI varied depending on the recruitment source.

Cerebrospinal fluid B-cell activating factor levels as a novel biomarker in patients with neurosarcoidosis.

OBJECTIVES: Neurosarcoidosis (NS) is a severe complication of sarcoidosis. Patients with NS often have poor outcomes. To improve both the quality of life and prognosis in patients with NS, accurate and reliable methods for early diagnosis and determining the efficacy of treatment are needed. This study aims to investigate B-cell-activating factor of the tumor necrosis factor family (BAFF) in cerebrospinal fluid (CSF) and elucidate the relationship between CSF BAFF levels and various parameters of NS. METHODS: We studied 20 patients with NS and 14 control subjects. We measured CSF BAFF levels in all subjects and investigated the relationship with clinical findings, serum and CSF measures, and magnetic resonance imaging (MRI) findings. RESULTS: CSF BAFF levels were significantly increased in patients with NS compared with controls (median 0.089 vs 0.04 ng/mL, p = 0.0005). CSF BAFF values were correlated with CSF findings-cell count, protein, angiotensin-converting enzyme, lysozyme, soluble interleukin-2 receptor, and immunoglobulin G-but not with serum parameters. CSF BAFF levels were especially higher in patients with abnormal intraparenchymal lesions of the brain and abnormal spinal MRI findings. CSF BAFF levels decreased significantly after immunosuppressive therapy. CONCLUSION: CSF BAFF may aid the quantitative evaluation of NS and may serve as a biomarker for this disease.

Cerebrospinal Fluid Interleukin-6 in Immune Checkpoint Inhibitor-Induced Autoimmune Meningoencephalitis.

Immune checkpoint inhibitors (ICIs) have proven clinical benefits in various advanced cancers. However, despite their significant therapeutic efficacy, ICIs induce immune-related adverse events. Among these events, autoimmune meningoencephalitis often has severe effects on patients' outcomes, but its specific clinical features are still unclear. Here, we report two cases of ICI-associated meningoencephalitis with elevated interleukin-6 (IL-6) levels in the cerebrospinal fluid (CSF). A 47-year-old woman (Case 1) with renal cell carcinoma developed severe headache after a seventh nivolumab administration. A neurological examination revealed jolt accentuation signs and hyperreflexia in all extremities. CSF analysis revealed a high IL-6 value (6,620 pg/mL) with marked pleocytosis. A 70-year-old woman (Case 2) who received an initial administration of nivolumab plus ipilimumab for renal cell carcinoma developed alterations of consciousness. She presented with impaired consciousness, neck stiffness, and hyperreflexia in all extremities. CSF analysis demonstrated a high IL-6 value (49.3 pg/mL) with mild pleocytosis. Both patients were treated with steroid pulse therapy (methylprednisolone 1,000 mg/day, 3 days), followed by the administration of oral predonisolone. The symptoms and laboratory findings improved in both cases. CSF IL-6 values were proportional to the severity of meningoencephalitis and other clinical parameters. These findings may help elucidate the mechanisms of central nervous system complications that are caused by ICIs.

α-Enolase reduces cerebrovascular Aß deposits by protecting Aß amyloid formation.

Cerebral amyloid angiopathy (CAA) is characterized by cerebrovascular amyloid ß (Aß) deposits and causes dementia and cerebral hemorrhage. Although α-enolase (ENO1) was shown to possess multifunctional roles, its exact functions in CAA pathogenesis have not been determined. In this study, we focused on ENO1, a well-known glycolytic enzyme, which was previously identified via a proteomic approach as an upregulated protein in brain samples from patients with Alzheimer's disease (AD). We utilized the thioflavin T fluorescence assay and transmission electron microscopy to monitor the effects of ENO1 on amyloid formation by Aß peptides. We also cultured murine primary cerebrovascular smooth muscle cells to determine the effects of ENO1 on Aß cytotoxicity. To investigate the effects of ENO1 in vivo, we infused ENO1 or a vehicle control into the brains of APP23 mice, a transgenic model of AD/CAA, using a continuous infusion system, followed by a cognitive test and pathological and biochemical analyses. We found that novel functions of ENO1 included interacting with Aß and inhibiting its fibril formation, disrupting Aß fibrils, and weakening the cytotoxic effects of these fibrils via proteolytic degradation of Aß peptide. We also demonstrated that infusion of ENO1 into APP23 mouse brains reduced cerebrovascular Aß deposits and improved cognitive impairment. In addition, we found that enzymatically inactivated ENO1 failed to inhibit Aß fibril formation and fibril disruption. The proteolytic activity of ENO1 may thus underlie the enzyme's cytoprotective effect and clearance of Aß from the brain, and ENO1 may be a therapeutic target in CAA.

Urinary Transthyretin as a Biomarker in ATTRv Val50Met Amyloidosis.

Transthyretin (TTR), the precursor protein for amyloidogenic TTR (ATTR) amyloidosis, forms tetramers and escapes glomerular filtration by binding with thyroxine and retinol-binding protein. However, variant TTRs are unstable as tetramers, so monomeric TTR has become the precursor protein of amyloid deposits, via protein misfolding. The aim of the study was to evaluate the utility of urinary TTR in the diagnosis of ATTRv amyloidosis. Urinary samples from healthy volunteers, ATTRv V50M amyloidosis patients, and asymptomatic carriers of the ATTRv V50M gene were analysed using ELISA. To analyse the different forms of TTR secreted to the urine, we performed Western blotting and mass spectrometry. Urinary TTR concentrations were significantly higher in the ATTRv V50M amyloidosis patients than they were in the healthy volunteers and asymptomatic carriers of the gene. Although the TTR concentrations were negligible in the healthy volunteers, they were correlated with disease progression and urinary albumin concentrations in the ATTRv V50M amyloidosis patients. The Western blotting and mass spectrometry revealed the presence of monomeric wild-type and variant TTRs in the urine. Urinary TTR concentrations may become a more sensitive biomarker of ATTRv progression than albumin.

Reversible Periventricular Hyperintensity Lesions in Cerebral Amyloid Angiopathy: A Case Mimicking Cerebral Amyloid Angiopathy-related Inflammation.

A 59-year-old man with progressive cognitive decline and mood disturbances was admitted to the hospital. Brain magnetic resonance imaging revealed marked white matter hyperintensity (WMH) and widespread lobar cerebral microbleeds. Because he had untreated hypertension, we started antihypertensive treatment and found a significantly improved cognitive function and WMH regression. We diagnosed him with cerebral amyloid angiopathy (CAA) based on the modified Boston Criteria with the rare apolipoprotein E (ApoE) ε2/ε4 genotype. The mechanism underlying reversible leukoencephalopathy in CAA may be related to the loss of autoregulation of brain circulation: cerebrovascular amyloid ß deposits damaged the blood-brain barrier of the capillaries, which led to vasogenic edema induced by blood pressure surges.

Three patients of transthyretin amyloidosis in a Japanese family with amyloidogenic transthyretin Thr49Ser (p.Thr69Ser) variant.

Transthyretin (TTR)-related hereditary amyloidosis (ATTRv) is a rare autosomal dominant disorder that is caused by pathogenic missense mutation of the TTR gene. As of today, more than 150 TTR gene variants have been reported to occur as causal mutations. Herein, we present three familial patients of ATTRv caused by the Thr49Ser (p.Thr69Ser) variant, including their phenotypes and penetrance. The first patient was a 68-year-old woman with a history of carpal tunnel syndrome, who was referred to our department with heart failure symptoms. Echocardiography, 99mTechnetium (Tc)-pyrophosphate scintigraphy, and myocardial biopsy confirmed her diagnosis as TTR-related amyloidosis. Genetic testing for the TTR gene was performed, which confirmed the presence of a Thr49Ser (p.Thr69Ser) variant. The second patient, a 45-year-old woman, who was the niece of the first patient, presented with dyspnea on exertion. Her clinical manifestations included cardiac symptoms in addition to polyneuropathy. Similarly, myocardial biopsy showed TTR amyloid deposition within cardiac tissues, and TTR gene sequencing detected the presence of a Thr49Ser (p.Thr69Ser) variant. The final patient was a 42-year-old man, who was the nephew of the first patient, presented with numbness in his hands. Abdominal wall fat pad biopsy showed TTR amyloid deposition, and TTR gene sequencing was performed considering the familial history to confirm the presence of Thr49Ser (p.Thr69Ser) variant. No cardiac symptoms or dysfunctions have been observed yet, but imaging has detected TTR amyloid deposition in the heart. The present three patients with Thr49Ser (p.Thr69Ser) variant showed variation in phenotypes including cardiac and neurological manifestations at a fairly young age. In addition, the familial relationship in this report suggested that this variant is highly penetrant. Early genetic diagnosis due to collecting the genetic information from family medical history may be beneficial to improve patient prognosis via early therapeutic intervention.

Preclinical diagnosis of wild-type transthyretin amyloid cardiomyopathy in a patient undergoing carpal tunnel release.

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) has received increased attention because of its novel treatment options. Carpal tunnel syndrome (CTS) is known as early symptoms in transthyretin amyloidosis (ATTR) preceding cardiac involvement and one of the "red flags" for ATTR-CM. A 64-year-old man underwent carpal tunnel release for carpal tunnel syndrome at 62 years. He was diagnosed with wild-type ATTR due to deposition of transthyretin (TTR) amyloid in flexor tenosynovium specimens and no TTR gene mutation. Examination for detection of cardiac involvement was performed after the operation, and there were no definitive findings of ATTR-CM; however, an early stage of ATTR-CM remained a possibility. Serial image evaluation and biomarker analysis revealed positive findings for ATTR-CM, and we performed an endomyocardial biopsy, resulting in the detection of amyloid deposition. He was diagnosed with ATTRwt-CM 2 years after the operation, and even then, he had no heart failure symptoms. Early diagnosis and treatment are important for the improvement of clinical outcomes in patients with ATTRwt-CM. TTR deposition in the ligaments or tendons is often observed in patients with CTS and should be considered at high risk of future ATTR-CM. Serial follow-up of these patients may enable the diagnosis of preclinical ATTR-CM. .

Glavonoid, a possible supplement for prevention of ATTR amyloidosis.

Transthyretin (TTR) is an amyloidogenic protein associated with hereditary and nonhereditary transthyretin amyloidoses (ATTR). Dissociation of the tetramer of TTR to the monomer induces TTR misfolding, which leads to amyloid fibril formation and triggers the onset of ATTR amyloidosis. Stabilizers of tetrameric TTR have been accepted as an effective ATTR amyloidosis treatment while effect is limited and they are too expensive. The aim of our study was to find more effective and cheep natural compound to suppress TTR amyloid formation. Glabridin, a prenylated isoflavan isolated from Glycyrrhiza glabra L., stabilized the TTR tetramer in vitro. The effects of licorice-derived flavonoid oil-Glavonoid, a natural substance that includes glabridin and several polyphenols-on stabilizing the TTR tetramer must still be elucidated. To examine plasma TTR stabilization by Glavonoid in vitro, we investigated the feasibility of utilizing glabridin plus Glavonoid to prevent TTR amyloid fibril formation. Glavonoid mixed with human plasma samples at 24 h incubation in vitro increased the tetramer level (P < 0.05) and reduced the monomer level (P < 0.01) and the monomer/tetramer ratio (P < 0.05) of TTR compared to those without Glavonoid by immunoblot analysis, such effect could not observe in the presence of glabridin. Oral Glavonoid (300 mg for 12 weeks) in 7 healthy volunteers effectively increased the plasma glabridin concentration. Glavonoid increased the TTR tetramer level and reduced the monomer/tetramer ratio of TTR (P < 0.05) in plasma at 12 weeks in healthy volunteers compared to those of age matched control subjects without the supplement. Thus, oral Glavonoid may effectively prevent TTR amyloid fibril formation via TTR tetramer stabilization. Glavonoid may become a promising supplement before onset of ATTR amyloidosis.

Metformin attenuates vascular pathology by increasing expression of insulin-degrading enzyme in a mixed model of cerebral amyloid angiopathy and type 2 diabetes mellitus.

Sporadic cerebral amyloid angiopathy (CAA), which is characterized by cerebrovascular amyloid ß (Aß) deposits, causes cerebral hemorrhages and dementia in elderly people. Metformin has been used to treat patients with type 2 diabetes mellitus (T2DM), and animal and clinical studies have reported therapeutic effects of metformin in Alzheimer's disease (AD). However, the therapeutic effects of metformin in CAA are unclear. Here, we used a mixed mouse model of CAA and T2DM (APP23-ob/ob) to investigate whether metformin has therapeutic effects on cerebrovascular Aß deposits. We dissolved metformin hydrochloride in water and administered it orally at 350 mg/kg/day. Treatments started when mice were 6 weeks old and continued until they were 15 months old. After we treated APP23-ob/ob mice with metformin, we counted the numbers of vessels with Aß and measured levels of Aß40 and Aß42 (soluble and insoluble), amyloid precursor protein (APP), APP-processing enzymes (α-, ß-, and γ-secretases), and Aß-degrading enzymes (insulin-degrading enzyme [IDE], neprilysin). Metformin significantly reduced cerebrovascular Aß deposits in APP23-ob/ob mice (p < .05). Compared with controls, metformin-treated APP23-ob/ob mice had significantly reduced Aß levels in the cerebral cortex (p < .05) and hippocampus (p < .05) and increased levels of IDE in the hippocampus (p < .01). Our results indicate that metformin attenuates the severity of CAA by enhancing Aß-cleaving IDE expression. The clinical application of metformin may lead to a novel therapeutic strategy in CAA treatment, especially in patients with T2DM.

Amyloid fibril formation is suppressed in microgravity.

In the future, humans may live in space because of global pollution and weather fluctuations. In microgravity, convection does not occur, which may change the amyloidogenicity of proteins. However, the effect of gravity on amyloid fibril formation is unclear and remains to be elucidated. Here, we analyzed the effect of microgravity on amyloid fibril formation of amyloidogenic proteins including insulin, amyloid ß42 (Aß42), and transthyretin (TTR). We produced microgravity (10-3 g) by using the gravity controller Gravite. Human insulin, Aß42, and human wild-type TTR (TTRwt) were incubated at pH 3.0, 7.0, and 3.5 at 37 °C, respectively, in 1 g on the ground or in microgravity. We measured amyloidogenicity via the thioflavin T (ThT) method and cell-based 1-fluoro-2,5-bis[(E)-3-carboxy-4-hydroxystyryl]benzene (FSB) assay. ThT fluorescence intensity and cell-based FSB assay results for human insulin samples were decreased in microgravity compared with results in 1 g. Aß42 samples did not differ in ThT fluorescence intensity in microgravity and in 1 g on the ground. However, in the cell-based FSB assay, the staining intensity was reduced in microgravity compared with that on 1 g. Human TTRwt tended to form fewer amyloid fibrils in ThT fluorescence intensity and cell-based FSB assays in microgravity than in 1 g. Human insulin and Aß42 showed decreased amyloid fibril formation in microgravity compared with that in 1 g. Human TTRwt tended to form fewer amyloid fibrils in microgravity. Our experiments suggest that the earth's gravity may be an accelerating factor for amyloid fibril formation.

Plasma growth differentiation factor 15: a novel tool to detect early changes of hereditary transthyretin amyloidosis.

AIMS: Hereditary transthyretin (ATTRv) amyloidosis is the most frequent and representative form of autosomal dominant hereditary systemic amyloidosis. Disease-modifying treatments of the disease are more effective during the early stages, and we require biomarkers to detect early pathological changes for prompt diagnosis. This study aimed to investigate whether plasma growth differentiation factor 15 (GDF-15) levels could aid detection of early pathological changes in ATTRv amyloidosis. METHODS AND RESULTS: We retrospectively studied 32 patients with ATTRv amyloidosis, eight asymptomatic TTR mutation carriers, and eight healthy volunteers. We evaluated plasma GDF-15 levels in these subjects as related to levels of brain natriuretic peptide and high-sensitivity troponin T, echocardiographic features, 99m Tc-pyrophosphate (PYP) scans, and cardiac magnetic resonance imaging findings. Plasma GDF-15 levels significantly increased even in asymptomatic TTR mutation carriers compared with healthy volunteers (P < 0.01). Plasma GDF-15 levels were significantly correlated with plasma brain natriuretic peptide values (P < 0.01), serum high-sensitivity troponin T values (P < 0.05), and interventricular septal thickness at end-diastole (P < 0.01) in patients with ATTRv amyloidosis. Plasma GDF-15 levels in patients with PYP-positive ATTRv amyloidosis were significantly higher than those in patients with PYP-negative ATTRv amyloidosis (P < 0.01). Plasma GDF-15 levels in patients with late gadolinium enhancement-positive ATTRv amyloidosis were significantly higher than those in patients with late gadolinium enhancement-negative ATTRv amyloidosis (P < 0.01). Groups of patients with different TTR genotypes manifested different plasma GDF-15 levels. CONCLUSIONS: Growth differentiation factor 15 may reflect early pathological changes of ATTRv amyloidosis.