Discontinuity third harmonic generation microscopy for label-free imaging and quantification of intraepidermal nerve fibers

Label-free imaging methodologies for nerve fibers rely on spatial signal continuity to identify fibers and fail to image free intraepidermal nerve endings (FINEs). Here, we present an imaging methodology-called discontinuity third harmonic generation (THG) microscopy (dTHGM)-that detects three-dimensional discontinuities in THG signals as the contrast. We describe the mechanism and design of dTHGM and apply it to reveal the bead-string characteristics of unmyelinated FINEs. We confirmed the label-free capability of dTHGM through a comparison study with the PGP9.5 immunohistochemical staining slides and a longitudinal spared nerve injury study. An intraepidermal nerve fiber (IENF) index based on a discontinuous-dot-connecting algorithm was developed to facilitate clinical applications of dTHGM. A preliminary clinical study confirmed that the IENF index was highly correlated with skin-biopsy-based IENF density (Pearson's correlation coefficient R = 0.98) and could achieve differential identification of small-fiber neuropathy (p = 0.0102) in patients with diabetic peripheral neuropathy.

Impact of Baseline Neuropathy Severity on Vutrisiran Treatment Response in the Phase 3 HELIOS-A Study

INTRODUCTION

Hereditary transthyretin (ATTRv, v for variant) amyloidosis is a rare, progressive, fatal disease with multisystem manifestations, caused by pathogenic variants in the transthyretin (TTR) gene. Vutrisiran, an RNA interference therapeutic that results in rapid TTR knockdown, improved neuropathy and quality of life (QOL) versus external placebo in patients with ATTRv amyloidosis with polyneuropathy in the phase 3 HELIOS-A study (NCT03759379). This post hoc analysis evaluates the impact of baseline neuropathy severity on response to vutrisiran treatment.

METHODS

Patients were randomized (3:1) to vutrisiran (n = 122; 25 mg subcutaneous injection once every 3 months) or patisiran (n = 42; 0.3 mg/kg intravenous infusion once every 3 weeks), which served as a reference group. In this post hoc analysis, patients were grouped into quartiles of increasing baseline Neuropathy Impairment Score (NIS): Quartile (Q)1 ≥ 5.0 to ≤ 20.5; Q2 > 20.5 to ≤ 44.1; Q3 > 44.1 to ≤ 73.1; Q4 > 73.1 to ≤ 127.0. Mean change from baseline to Month 18 was summarized by quartile for a range of efficacy endpoints.

RESULTS

Across all baseline NIS quartiles, vutrisiran demonstrated benefit versus external placebo in measures of neuropathy severity (modified NIS + 7), QOL (Norfolk Quality of Life-Diabetic Neuropathy), disability (Rasch-built Overall Disability Scale), gait speed (10-m walk test), and nutritional status (modified body mass index). Overall, patients in lower versus higher NIS quartiles (less severe neuropathy) at baseline maintained better scores at Month 18. The external placebo group progressively worsened in all measures at Month 18.

CONCLUSIONS

Vutrisiran demonstrated benefit in neurologic function and other key efficacy measures versus external placebo across all four baseline neuropathy severity quartiles. Patients initiating vutrisiran earlier in their disease course retained the highest neurologic function level after 18 months, highlighting the importance of early diagnosis and treatment.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT03759379.

Altered gut microbiota in Taiwanese A97S predominant transthyretin amyloidosis with polyneuropathy

Increasing evidence suggests that gut microbiota alterations are related to development and phenotypes of many neuropsychiatric diseases. Here, we evaluated the fecal microbiota and its clinical correlates in patients with hereditary transthyretin amyloidosis (ATTRv) and polyneuropathy. Fecal microbiota from 38 ATTRv patients and 39 age-matched controls was analyzed by sequencing 16S V3-V4 ribosomal RNA, and its relationships with clinical characteristics of polyneuropathy and cardiomyopathy were explored. The familial amyloidotic polyneuropathy stage was stage I, II, and III in 13, 18, and 7 patients. 99mTc-PYP SPECT showed a visual score of 2 in 15 and 3 in 21 patients. The gut microbiota of ATTRv patients showed higher alpha diversity (ASV richness and Shannon effective numbers) and dissimilar beta diversity compared to controls. Relative abundance of microbiota was dominated by Firmicutes and decreased in Bacteroidetes in ATTRv patients than in controls. Patients with more myocardial amyloid deposition were associated with increased alpha diversity, and the abundance of Clostridia was significantly correlated with pathophysiology of polyneuropathy in ATTRv patients. These findings demonstrated alterations in the gut microbiota, especially Firmicutes, in ATTRv. The association between altered microbiota and phenotypes of cardiomyopathy and polyneuropathy might suggest potential contributions of gut microbiota to ATTRv pathogenesis.

The effects of double-filtration plasmapheresis on coagulation profiles and the risk of bleeding

BACKGROUND/PURPOSE

Double-filtration plasmapheresis (DFPP) can be used to remove circulating pathogenic molecules. By reclaiming filtered albumin, DFPP reduces the need for albumin and plasma replacement. Large proteins, such as fibrinogen, are removed. Our institution adopts a DFPP treatment protocol consisting of active surveillance of coagulation profiles and prophylactic supplementation of blood products containing fibrinogen. This study aims to investigate the effects of consecutive DFPP treatments on serial coagulation profiles and the risk of bleeding under this protocol.

METHODS

Serial laboratory data and bleeding events at a single tertiary medical center were prospectively collected. Prophylactic transfusion of cryoprecipitate or fresh frozen plasma (FFP) was instituted if significant coagulopathy or a clinically evident bleeding event was observed.

RESULTS

After the first treatment session, plasma fibrinogen levels decreased from 332 ± 106 mg/dL to 96 ± 44 mg/dL in the 37 study patients. In the following sessions, plasma fibrinogen levels were maintained at around 100 mg/dL under prophylactic transfusion. No major bleeding events were recorded, but five (14%) patients experienced minor bleeding.

CONCLUSION

DFPP treatment might be performed safely along with active monitoring of coagulation profiles and prophylactic transfusion of cryoprecipitate or FFP.

Tafamidis improves myocardial longitudinal strain in A97S transthyretin cardiac amyloidosis

Background

Transthyretin cardiomyopathy (ATTR-CM) is a debilitating disease that has received much attention since the emergence of novel treatments. The Transthyretin Cardiomyopathy Clinical Trial showed that tafamidis, a transthyretin tetramer stabilizer, effectively reduced the declines in functional capacity and quality of life. However, Ala97Ser (A97S) hereditary ATTR-CM is underrepresented in major ATTR-CM tafamidis trials.

Objectives

We aim to investigate the change in global longitudinal strain (GLS) of A97S ATTR-CM patients after 12 months of tafamidis treatment.

Methods

We retrospectively analysed a prospective cohort of patients with A97S ATTR-CM who received tafamidis meglumine (61 mg/day) at the National Taiwan University Hospital. Echocardiography with speckle tracking strain analysis was performed at baseline and 12 months after treatment.

Results

In all, 20 patients were included in the cohort. The baseline left ventricular ejection fraction (LVEF) and interventricular septum (IVS) thickness were 59.20 ± 13.23% and 15.10 ± 3.43 mm, respectively. After 12 months of tafamidis treatment, the LVEF and IVS were 61.83 ± 15.60% (p = 0.244) and 14.59 ± 3.03 mm (p = 0.623), respectively. GLS significantly improved from -12.70 ± 3.31% to -13.72 ± 3.17% (p = 0.048), and longitudinal strain (LS) in apical and middle segments significantly improved from -16.05 ± 4.82% to -17.95 ± 3.48% (p = 0.039) and -11.89 ± 4.38% to -13.58 ± 3.12% (p = 0.039), respectively. Subgroup analysis showed that patients with LVEF < 50% had a better treatment response and improvement in GLS. The patients with an IVS ⩾ 13 mm had an improvement in two-chamber LS from -10.92 ± 4.25% to -13.15 ± 3.87% (p = 0.042) and an improvement in apical left ventricular LS from -15.30 ± 5.35% to -17.82 ± 3.99% (p = 0.031).

Conclusion

Tafamidis significantly improved GLS, and particularly apical and middle LS in A97S ATTR-CM patients.

Comparison of contrast-enhanced ultrasonography and MRI results obtained by expert and novice radiologists indicating short-term response after transarterial chemoembolisation for hepatocellular carcinoma

AIM

To evaluate inter-reader agreement between novice and expert radiologists in assessing contrast-enhanced ultrasonography (CEUS) and magnetic resonance imaging (MRI) images for detecting viable tumours with different sizes after conventional transarterial chemoembolisation (cTACE).

MATERIALS AND METHODS

This prospective study included patients who had less than five hepatomas and who underwent cTACE. Hepatomas with one or two feeding arteries were selected as target lesions. CEUS and MRI were performed within 1 week after cTACE to evaluate viable tumours.

RESULTS

The expert group had higher kappa values in evaluating all tumour sizes via CEUS compared with MRI. The novice group had similar kappa values. In patients with tumours measuring ≤3 cm, the expert group had higher kappa values in reading CEUS compared with MRI images; however, in the novice group, the kappa value was lower in evaluating CEUS compared with MRI images. In patients with tumours measuring >3 cm, the expert and novice groups had good to excellent kappa values. The confidence level of the two groups in reading MRI images was high; however, the novice group had a lower confidence level.

CONCLUSION

CEUS is a convenient, cost-effective, and easy to apply imaging tool that can help interventionists perform early detection of viable hepatocellular carcinoma post-TACE. It has a higher inter-rater agreement in interpreting CEUS images compared with MRI images among expert radiologists even when they are extremely familiar with post-cTACE MRI images. In novice radiologists, there may be a learning curve to achieve good consistency in CEUS interpretation.

Eplontersen for Hereditary Transthyretin Amyloidosis With Polyneuropathy

Importance

Transthyretin gene silencing is an emerging treatment strategy for hereditary transthyretin (ATTRv) amyloidosis.

Objective

To evaluate eplontersen, an investigational ligand-conjugated antisense oligonucleotide, in ATTRv polyneuropathy.

Design, Setting, and Participants

NEURO-TTRansform was an open-label, single-group, phase 3 trial conducted at 40 sites across 15 countries (December 2019-April 2023) in 168 adults with Coutinho stage 1 or 2 ATTRv polyneuropathy, Neuropathy Impairment Score 10-130, and a documented TTR variant. Patients treated with placebo from NEURO-TTR (NCT01737398; March 2013-November 2017), an inotersen trial with similar eligibility criteria and end points, served as a historical placebo ("placebo") group.

Interventions

Subcutaneous eplontersen (45 mg every 4 weeks; n = 144); a small reference group received subcutaneous inotersen (300 mg weekly; n = 24); subcutaneous placebo weekly (in NEURO-TTR; n = 60).

Main Outcomes and Measures

Primary efficacy end points at week 65/66 were changes from baseline in serum transthyretin concentration, modified Neuropathy Impairment Score +7 (mNIS+7) composite score (scoring range, -22.3 to 346.3; higher scores indicate poorer function), and Norfolk Quality of Life Questionnaire-Diabetic Neuropathy (Norfolk QoL-DN) total score (scoring range, -4 to 136; higher scores indicate poorer quality of life). Analyses of efficacy end points were based on a mixed-effects model with repeated measures adjusted by propensity score weights.

Results

Among 144 eplontersen-treated patients (mean age, 53.0 years; 69% male), 136 (94.4%) completed week-66 follow-up; among 60 placebo patients (mean age, 59.5 years; 68% male), 52 (86.7%) completed week-66 follow-up. At week 65, adjusted mean percentage reduction in serum transthyretin was -81.7% with eplontersen and -11.2% with placebo (difference, -70.4% [95% CI, -75.2% to -65.7%]; P < .001). Adjusted mean change from baseline to week 66 was lower (better) with eplontersen vs placebo for mNIS+7 composite score (0.3 vs 25.1; difference, -24.8 [95% CI, -31.0 to -18.6; P < .001) and for Norfolk QoL-DN (-5.5 vs 14.2; difference, -19.7 [95% CI, -25.6 to -13.8]; P < .001). Adverse events by week 66 that led to study drug discontinuation occurred in 6 patients (4%) in the eplontersen group vs 2 (3%) in the placebo group. Through week 66, there were 2 deaths in the eplontersen group consistent with known disease-related sequelae (cardiac arrhythmia; intracerebral hemorrhage); there were no deaths in the placebo group.

Conclusions and Relevance

In patients with ATTRv polyneuropathy, the eplontersen treatment group demonstrated changes consistent with significantly lowered serum transthyretin concentration, less neuropathy impairment, and better quality of life compared with a historical placebo.

Trial Registration

ClinicalTrials.gov Identifier: NCT04136184; EU Clinical Trials Register: EudraCT 2019-001698-10.

Automated Detection, Segmentation, and Tracking of Brain Metastases in Repeated Courses of Stereotactic Radiosurgery Using Integrated Artificial Intelligence

PURPOSE/OBJECTIVE(S)

Salvage stereotactic radiosurgery (SRS) for distant brain metastases has been demonstrated as a safe and effective approach for intracranial recurrences after initial SRS. However, accurate tumor detection and segmentation among responding tumors within the irradiated parenchyma can be challenging. The requirement for the registration and reference to the previous course of SRS is very time-consuming and suffers significant inter and intra-reader variability. Artificial intelligence (AI)-assisted system has been proven to improve the accuracy and efficiency in the clinical flow of de-novo SRS. We hypothesize that an integrated AI system can facilitate an automated tumor contouring process for repeated SRS.

MATERIALS/METHODS

Three patients who underwent their third course of SRS to brain metastases were selected for the pioneering works. They have had two sessions of SRS with a mean lesion number of 4 and 3.7, respectively. VBrain, an FDA-approved brain tumor management AI platform, was used to co-registered serial MR scans and automatically identify, track, and contour brain metastases for each course of SRS. The AI also indicated new lesions and treated lesions for each course. Three radiation oncologists experienced in brain SRS contoured the gross tumor volumes (GTVs) of the third course of SRS in two reader modes (assisted then unassisted) with a memory washout period of one week between each section. The segmentation ground truth was established through consensus among the three experts. Lesion-wise sensitivity, contouring accuracy, and consuming time were compared between the two contouring modes.

RESULTS

In each patient, there were 15, 11, and 9 metastases, with a median diameter of 4.72 (95% CI: 4.05, 6.91) mm. The mean lesion-wise sensitivity was 96.96±2.47% with AI assistance and 76.90 ± 7.10% without assistance. There were two false-positive lesions in the assisted read, resulting in a low average false-positive rate of 0.67 per patient, while no false positive for the unassisted mode. AI assistance improved contouring accuracy. The median Dice similarity coefficient (DSC) was 0.71 (95% CI: 0.55, 0.87) for assisted contouring and 0.65 (95% CI: 0.46, 0.85) for unassisted contouring. We also use average Hausdorff distance (HD) to measure segmentation results. The mean HD was 0.72± 0.13 mm versus 0.73±0.08 mm for the two contouring modes (p = 0.02) Furthermore, the median contouring time per case was significantly shorter with AI assistance than without assistance (20.8 minutes vs. 29.8 minutes; p < 0.001), corresponding to a 43.2% time-saving.

CONCLUSION

Our results suggest that the integration of an AI-based system into repeated brain SRS can significantly improve the accuracy and efficiency of tumor detection and segmentation. This approach has the potential to streamline the treatment planning process for salvage SRS.

Tafamidis decreased cardiac amyloidosis deposition in patients with Ala97Ser hereditary transthyretin cardiomyopathy: a 12-month follow-up cohort study

BACKGROUND

Transthyretin cardiac cardiomyopathy (ATTR-CM) is a rare but life-threatening disease. Tafamidis is an effective treatment for patients with ATTR-CM, however its long-term effects on cardiac remodeling and cardiac amyloid deposition are unknown. This study aimed to used cardiac magnetic resonance (CMR) to investigate the effects of tafamidis on patients with hereditary A97S ATTR-CM.

METHODS

We retrospectively analyzed a prospective cohort of ATTR-CM patients, including 14 with hereditary A97S ATTR-CM and 17 healthy controls with baseline CMR data. All ATTR-CM patients received tafamidis treatment and received CMR with extracellular volume (ECV) at baseline and after 1 year of follow-up.

RESULTS

Baseline N-terminal pro-B-type natriuretic peptide, left ventricular (LV) mass, LV ejection fraction, global radial, circumferential and longitudinal strain, T1 mapping and ECV were significantly worse in the patients with ATTR-CM compared with the healthy controls. After 1 year of tafamidis treatment, ECV decreased from 51.5 ± 8.9% to 49.0 ± 9.4% (P = 0.041), however there were no significant changes in LV mass, LV ejection fraction, global radial strain, global circumferential strain, global longitudinal strain and T1 mapping.

CONCLUSIONS

After a one-year treatment period, tafamidis exhibited subtle but statistically significant reductions in ECV, potentially indicating a decrease in amyloid deposition among patients diagnosed with hereditary A97S ATTR-CM.

Identification of an 85-kb Heterozygous 4p Microdeletion With Full Genome Analysis in Autosomal Dominant Charcot-Marie-Tooth Disease

Background and Objectives

Charcot-Marie-Tooth disease (CMT) is a syndrome of a hereditary neurodegenerative condition affecting the peripheral nervous system and is a single gene disorder. Deep phenotyping coupled with advanced genetic techniques is critical in discovering new genetic defects of rare genetic disorders such as CMT.

Methods

We applied multidisciplinary investigations to examine the neurophysiology and nerve pathology in a family that fulfilled the diagnosis of CMT2. When phenotype-guided first-tier genetic tests and whole-exome sequencing did not yield a molecular diagnosis, we conducted full genome analysis by examining phased whole-genome sequencing and whole-genome optical mapping data to search for the causal variation. We then performed a systematic review to compare the reported patients with interstitial microdeletion in the short arm of chromosome 4.

Results

In this family with CMT2, we reported the discovery of a heterozygous 85-kb microdeletion in the short arm of chromosome 4 (4p16.3)[NC_000004.12:g.1733926_1819031del] spanning 3 genes [TACC3 (intron 6-exon 16), FGFR3 (total deletion), and LETM1 (intron 10-exon14)] that cosegregated with disease phenotypes in family members. The clinical features of peripheral nerve degeneration in our family are distinct from the well-known 4p microdeletion syndrome of Wolf-Hirschhorn syndrome, in which brain involvement is the major phenotype.

Discussion

In summary, we used the full genome analysis approach to discover a new microdeletion in a family with CMT2. The deleted segment contains 3 genes (TACC3, FGFR3, and LETM1) that likely play a role in the pathogenesis of nerve degeneration.

Efficacy of Tafamidis in Patients with Ala97Ser Hereditary Transthyretin Cardiac Amyloidosis: A Six-Month Follow-Up Study

Background

Hereditary transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive and fatal disease. A97S (p.Ala117Ser) is the most common transthyretin genetic mutation in Taiwan. Tafamidis is a transthyretin stabilizer, and it has been shown to improve outcomes. However, its effect on A97S ATTR-CM subtypes remains unknown.

Objectives

This study aimed to investigate the efficacy of tafamidis in patients with hereditary A97S ATTR-CM after 6 months of treatment.

Methods

We retrospectively analyzed ATTR-CM patients who received tafamidis (61 mg/day) treatment at National Taiwan University Hospital. Functional status, biochemistry and echocardiography were measured at baseline and after 6 months of tafamidis treatment. The outcome measure was to compare the N-terminal pro-brain natriuretic peptide (NT-proBNP) level at baseline and after 6 months of tafamidis treatment.

Results

Twenty patients were enrolled in this study. Their mean age was 63.0 ± 5.8 years and 75% were men. The baseline left ventricular (LV) mass index was 200.9 ± 63.9 g/m², and the baseline LV ejection fraction was 58.9 ± 13.5%. After 6 months of treatment, the log NT-proBNP level significantly improved from 2.9 ± 0.6 to 2.7 ± 0.5 (p = 0.036). Subgroup analysis showed that the LV posterior wall thickness and left atrial diameter were significantly higher in the patients with improved NT-proBNP, suggesting the benefits of tafamidis for ATTR-CM patients with severe cardiac involvement.

Conclusions

The patients with hereditary A97S ATTR-CM in this study had decreased levels of NT-proBNP after 6 months of tafamidis treatment, and this reduction was especially pronounced in those with more severe cardiac involvement.

Diagnostic Challenges of Neuromuscular Disorders after Whole Exome Sequencing

BACKGROUND

Whole-exome sequencing (WES) facilitates the diagnosis of hereditary neuromuscular disorders. To achieve an accurate diagnosis, physicians should interpret the genetic report carefully along with clinical information and examinations. We described our experience with (1) clinical validation in patients with variants found using WES and (2) a diagnostic approach for those with negative findings from WES.

METHODS

WES was performed on patients with the clinical impression of hereditary neuromuscular disorders. Information on clinical manifestations, neurological examination, electrodiagnostic studies, histopathology of muscle and nerve, and laboratory tests were collected.

RESULTS

Forty-one patients (Male/Female: 18/23, age of onset: 34.5±15.9) accepted WES and were categorized into four scenarios: (1) patients with a positive WES result, (2) patients with an inconclusive WES result but supporting clinical data, (3) negative findings from WES, but a final diagnosis after further work-up, and (4) undetermined etiology from WES and in further work-ups. The yield rate of the initial WES was 63.4% (26/41). Among these, seventeen patients had positive WES result, while the other nine patients had inconclusive WES result but supporting clinical data. Notably, in the fifteen patients with equivocal or negative findings from WES, four patients (26.7%) achieved a diagnosis after further workup: tumor-induced osteomalacia, metabolic myopathy with pathogenic variants in mitochondrial DNA, microsatellite expansion disease, and vasculitis-related neuropathy. The etiologies remained undetermined in eleven patients (myopathy: 7, neuropathy: 4) after WES and further workup.

CONCLUSIONS

It is essential to design genotype-guided molecular studies to correlate the identified variants with their clinical features. For patients who had negative findings from WES, acquired diseases, mitochondrial DNA disorders and microsatellite expansion diseases should be considered.

On-Table Catheter-Based Neurosalvage Performed by Cardiologists for Embolic Complication during an Endovascular Procedure

Objectives

To report our experience and clinical results of neurosalvage techniques, performed by interventional cardiologists without moving the patient, to manage cerebral thromboembolic complications.

Background

Iatrogenic emboli may be released during an endovascular procedure, causing permanent neurological complications and catastrophic outcomes.

Methods

Between July 2013 and December 2017, a total of eight patients suffered from embolic complications during endovascular procedures (two radiofrequency catheter ablation, five coronary angiogram/angioplasty, and one subclavian artery angioplasty). Catheter-based neurosalvage was attempted by experienced interventional cardiologists promptly in the same catheterization room.

Results

The embolized locations were the M1 segment of the middle cerebral artery in four patients, the M2/M3 segments in three, and the basilar artery in one. Access to the supra-aortic vessels was achieved. Local intra-arterial thrombolysis was given in five patients (63%) and balloon angioplasty in three (38%). Intra-arterial thrombectomy with a stent retriever was attempted in three patients but failed in one. A combination of different techniques was used in three patients (38%). Final thrombolysis in cerebral infarction grade 3 flow was achieved in seven patients (88%). Favorable clinical outcomes at 1-month follow-up (modified Rankin scale of 0-2) were observed in seven patients (88%), and none of the patients had died at 12 months.

Conclusions

Our experience demonstrated that acute embolic complications during an endovascular procedure can be salvaged by interventional cardiologists with acceptable angiographic and clinical results.

Limbic Connectivity Underlies Pain Treatment Response in Small-Fiber Neuropathy

OBJECTIVE

Small-fiber neuropathy (SFN) is characterized by neuropathic pain due to degeneration of small-diameter nerves in the skin. Given that brain reorganization occurs following chronic neuropathic pain, this study investigated the structural and functional basis of pain-related brain changes after skin nerve degeneration.

METHODS

Diffusion-weighted and resting-state functional MRI data were acquired from 53 pathologically confirmed SFN patients, and the structural and functional connectivity of the pain-related network was assessed using network-based statistic (NBS) analysis.

RESULTS

Compared with age- and sex-matched controls, the SFN patients exhibited a robust and global reduction of functional connectivity, mainly across the limbic and somatosensory systems. Furthermore, lower functional connectivity was associated with skin nerve degeneration measured by reduced intraepidermal nerve fiber density and better therapeutic response to anti-neuralgia medications, particularly for the connectivity between the insula and the limbic areas including the anterior and middle cingulate cortices. Similar to the patterns of functional connectivity changes, the structural connectivity was robustly reduced among the limbic and somatosensory areas, and the cognition-integration areas including the inferior parietal lobule. There was shared reduction of structural and functional connectivity among the limbic, somatosensory, striatal, and cognition-integration systems: (1) between the middle cingulate cortex and inferior parietal lobule and (2) between the thalamus and putamen. These observations indicate the structural basis underlying altered functional connectivity in SFN.

INTERPRETATION

Our findings provide imaging evidence linking structural and functional brain dysconnectivity to sensory deafferentation caused by peripheral nerve degeneration and therapeutic responses for neuropathic pain in SFN. ANN NEUROL 2022.

Small Fiber Pathology in CADASIL: Clinical Correlation With Cognitive Impairment

BACKGROUND AND OBJECTIVES

This study investigated the cutaneous small fiber pathology of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and its clinical significance, that is, the NOTCH3 deposition in cutaneous vasculatures and CNS neurodegeneration focusing on cognitive impairment.

METHODS

Thirty-seven patients with CADASIL and 59 age-matched healthy controls were enrolled to evaluate cutaneous small fiber pathology by quantitative measures of intraepidermal nerve fiber density (IENFD), sweat gland innervation, and vascular innervation. Cognitive performance of patients with CADASIL was evaluated by a comprehensive neuropsychological assessment, and its association with small fiber pathology was tested using multivariable linear regression analysis adjusted for age and diabetes mellitus. We further assessed the relationships of IENFD with cutaneous vascular NOTCH3 ectodomain (NOTCH3ECD) deposition and biomarkers of neurodegeneration including structural brain MRI measures, serum neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), tau, and ubiquitin carboxy-terminal hydrolase L1.

RESULTS

Patients with CADASIL showed reduced IENFD (5.22 ± 2.42 vs 7.88 ± 2.89 fibers/mm, p = 0.0001) and reduced sweat gland (p < 0.0001) and vascular (p < 0.0001) innervations compared with age-matched controls. Reduced IENFD was associated with impaired global cognition measured by Mini-Mental State Examination (B = 1.062, 95% CI = 0.370-1.753, p = 0.004), and this association remained after adjustment for age and diabetes mellitus (p = 0.043). In addition, IENFD in patients with CADASIL was associated with mean cortical thickness (Pearson r = 0.565, p = 0.0023) but not white matter hyperintensity volume, total lacune count, or total microbleed count. Reduced IENFD was associated with cutaneous vascular NOTCH3ECD deposition amount among patients harboring pathogenic variants in exon 11 (mainly p.R544C) (B = -0.092, 95% CI = -0.175 to -0.009, p = 0.031). Compared with those with normal cognition, patients with CADASIL with cognitive impairment had an elevated plasma NfL level regardless of concurrent small fiber denervation, whereas only patients with both cognitive impairment and small fiber denervation showed an elevated plasma GFAP level.

DISCUSSION

Cutaneous small fiber pathology correlates with cognitive impairment and CNS neurodegeneration in patients with CADASIL, indicating a peripheral neurodegenerative process related to NOTCH3ECD aggregation.

Cardiomyopathy correlates to nerve damage in p.A117S late-onset transthyretin amyloid polyneuropathy

Objective

Late‐onset hereditary transthyretin amyloidosis with polyneuropathy (ATTRv‐PN) is often associated with heart involvement. Recent advances in cardiac imaging allow the detection of cardiac amyloidosis. This study aimed to explore cardiomyopathy by cardiac imaging and its clinical correlates with polyneuropathy in late‐onset ATTRv‐PN.

Methods

Polyneuropathy was assessed by intraepidermal nerve fiber (IENF) density, nerve conduction study (NCS), autonomic function tests, quantitative sensory testing, and clinical questionnaires. Cardiomyopathy was evaluated by echocardiography, ^99mTc‐pyrophosphate (PYP) single‐photon emission computed tomography (SPECT) imaging, cardiac magnetic resonance imaging (CMR), and serum Pro‐B‐type natriuretic peptide. Healthy controls and patients with Brugada syndrome were enrolled for comparison of CMR.

Results

Fifty late‐onset ATTRv‐PN patients (38 men, 46 with p. A117S mutation), aged 63.7 ± 5.5 years, of polyneuropathy disability stage 1–4 were enrolled. All patients presented polyneuropathy in NCS, and 74.5% of patients had reduced IENF density in distal legs. All patients showed significant radiotracer uptake in the heart on ^99mTc‐PYP SPECT imaging, and 87.8% of patients had abnormally increased left ventricular (LV) septum thickness on echocardiography. CMR showed longer myocardial native T1, larger extracellular volume, greater LV mass index, and higher LV mass to end‐diastolic volume ratio in ATTRv‐PN patients than healthy controls and patients with Brugada syndrome. These CMR parameters were associated with skin denervation, absent sympathetic skin responses, elevated thermal thresholds, worsened NCS profiles, and functional deficits of polyneuropathy.

Interpretation

Late‐onset ATTRv‐PN coexisted with cardiomyopathy regardless of the clinical severity of polyneuropathy. The cardiac amyloid burden revealed by CMR was correlated with pathophysiology and clinical disability of nerve degeneration.

Serial neurocognitive changes following transcatheter aortic valve replacement: comparison between low and intermediate-high risk groups

Background: Data comparing the neurocognitive trajectory between low and intermediate-high risk patients following transcatheter aortic valve replacement (TAVR) is never reported.

Aims: To report serial neurocognitive changes up to 1 year post-TAVR in low and intermediate-high risk groups as well as overall cohort.

Methods: Prospective neurological assessments (NIHSS and Barthel Index), global cognitive tests (MMSE and Alzheimer Disease Assessment Scale–Cognitive Subtest, ADAS-cog) and executive performances (Color Trail Test A and B and verbal fluency), were applied at baseline, 3 months and 1 year post-TAVR.

Results: In overall cohort, persistent improvement to 1 year in MMSE, ADAS-cog, Color Trail Test A and B was found. According to the STS score, the study cohort was divided into low (<4%, N = 81) and intermediate-high (≧4%, N = 75) risk groups. The baseline neurologic and cognitive performance was significantly worse in intermediate-high risk group. Slight improvement on general neurological functions (Barthel index and proportion of NIHSS>0 patients) at 1 year could be observed only in intermediate-high risk group. In global cognitive assessments, improvement in MMSE and ADAS-cog at 1 year was found in both groups, but the proportion of cognitive improvement was more obvious in intermediate-high risk group. In Color Trail Tests and verbal fluency, significant and persistent improvement up to 1 year could be observed only in low risk group.

Conclusions: TAVR was associated with persistent improvement in global cognitive function, as well as in attention and psychomotor processing speed, up to 1 year in overall cohort. However, improvement in tests for executive functions can only be seen in low risk group.

Electrodiagnosis of Guillain-Barre syndrome in the International GBS Outcome Study: Differences in methods and reference values

OBJECTIVE

To describe the heterogeneity of electrodiagnostic (EDx) studies in Guillain-Barré syndrome (GBS) patients collected as part of the International GBS Outcome Study (IGOS).

METHODS

Prospectively collected clinical and EDx data were available in 957 IGOS patients from 115 centers. Only the first EDx study was included in the current analysis.

RESULTS

Median timing of the EDx study was 7 days (interquartile range 4-11) from symptom onset. Methodology varied between centers, countries and regions. Reference values from the responding 103 centers were derived locally in 49%, from publications in 37% and from a combination of these in the remaining 15%. Amplitude measurement in the EDx studies (baseline-to-peak or peak-to-peak) differed from the way this was done in the reference values, in 22% of motor and 39% of sensory conduction. There was marked variability in both motor and sensory reference values, although only a few outliers accounted for this.

CONCLUSIONS

Our study showed extensive variation in the clinical practice of EDx in GBS patients among IGOS centers across the regions.

SIGNIFICANCE

Besides EDx variation in GBS patients participating in IGOS, this diversity is likely to be present in other neuromuscular disorders and centers. This underlines the need for standardization of EDx in future multinational GBS studies.

Distinct Patterns of Amyloid Pathology in Autopsies of Transthyretin S77Y and A97S Amyloidosis: Significance of Symptomatology and Cell Biology

Hereditary transthyretin (ATTRv) amyloidosis is a systemic disease with amyloid deposition in the peripheral and autonomic nervous systems caused by mutation of transthyretin (TTR) gene. The mutant TTR S77Y is the second prevalent mutation in many countries. In Taiwan, A97S mutant accounts for more than 90% of cases. Although distinct clinical manifestations such as dysphagia, carpal tunnel syndrome, and sudden cardiac death occur, the underlying pathology has not been elucidated. Here, we report the first autopsy cases of ATTRv S77Y and A97S and comprehensively compare the pathology underlying the unique clinical manifestations. This study demonstrated the following: (1) distinct spatial patterns of amyloid deposits in peripheral nerves, with a tendency toward more amyloid deposition in the large peripheral nerves, particularly the median nerves, and scarcely in the sural nerves, and different amyloid distribution in different genotypes; (2) amyloid deposits in the conduction system of the heart in addition to surrounding cardiomyocytes; (3) extensive amyloid deposits in the larynx and gastrointestinal tract, contributing to the unique clinical symptom of dysphagia; and (4) characteristic TTR intracytoplasmic inclusions in the hepatocytes of A97S. The pathology of the first autopsied cases of ATTRv S77Y and A97S provides pathology and mechanisms underlying unique clinical manifestations.

Impaired brain network architecture as neuroimaging evidence of pain in diabetic neuropathy

AIMS

To investigate alterations in structural brain networks due to chronic diabetic neuropathic pain.

METHODS

The current study recruited 24 patients with painful diabetic neuropathy (PDN) to investigate the influences of chronic pain on the brain. Thirteen patients with painless diabetic neuropathy (PLDN) and 24 healthy adults were recruited as disease and healthy controls. White matter connectivity of the brain networks constructed by diffusion tractography was compared across groups using the Network-based statistic (NBS) method. Graph theoretical analysis was further applied to assess topological changes of the brain networks.

RESULTS

The PDN patients had a significant reduction in white matter connectivity compared with PLDN and controls in the limbic and temporal regions, particularly the insula, hippocampus and parahippocampus, the amygdala, and the middle temporal gyrus. The PDN patients also exhibited an altered topology of the brain networks with reduced global efficiency and betweenness centrality.

CONCLUSION

The current findings indicate that topological alterations of brain networks may serve as a biomarker for pain-induced maladaptive reorganization of the brain in PDN. Given the high prevalence of diabetes worldwide, novel insights from network sciences to investigate the central mechanisms of diabetic neuropathic pain are warranted.

Diabetic visceral neuropathy of gastroparesis: gastric mucosal innervation and clinical significance

BACKGROUND

The pathogenesis of diabetic gastroparesis due to visceral neuropathy involves multi-dimensional mechanisms with limited exploration of gastric mucosal innervation. This study aimed to quantitatively examine this topic and its relationship with gastroparesis symptoms and gastric emptying in diabetes.

METHODS

We prospectively enrolled 22 patients with type 2 diabetes and gastroparesis symptoms and 25 age- and gender-matched healthy controls for comparison. The assessments include (1) neuropathology with quantification of gastric mucosal innervation density (MID) on endoscopic biopsy, (2) clinical manifestations with questionnaire of gastroparesis cardinal symptom index (GCSI), and (3) functional tests of gastric emptying scintigraphy (GES).

RESULTS

In diabetic patients, stomach fullness, bloating, and feeling excessively full after meals constituted the most common GCSI symptoms. Seven (32%) diabetic patients had prolonged gastric emptying patterns. In diabetes, gastric MID was significantly lower in all examined parts compared with the controls: antrum (294.8±237.0 vs. 644.0±222.0mm/mm³ , p<0.001), body (292.2±239.0 vs. 652.6±260.9mm/mm³ , p<0.001), and fundus (238.0±109.1 vs. 657.2±332.8mm/mm³ , p<0.001). Gastric MID was negatively correlated with gastroparesis symptoms and total scores of GCSI (p<0.001). Furthermore, gastric MID in the fundus was negatively correlated with fasting glucose and HbA1c levels. Gastric emptying parameters, including T_1/2 and gastric retention, were prolonged in diabetes and gastric retention at 3h was correlated with fasting glucose level.

CONCLUSION

In diabetes, gastric MID was reduced and GES parameters were prolonged. Both were correlated with gastroparesis symptoms and glycemic control. These findings provide pathology and functional biomarkers for diabetic visceral neuropathy of gastroparesis and underlying pathophysiology.

Nonpermissive skin environment impairs nerve regeneration in diabetes via Sec31a

OBJECTIVE

Although the microenvironment for peripheral nerve regeneration is permissive, such a mechanism is defective in diabetes, and the molecular mediators remain elusive. This study aimed to (1) investigate the relationship between skin innervation and collagen pathology in diabetic neuropathy and to (2) clarify the molecular alterations that occur in response to hyperglycemia and their effects on axon regeneration.

METHODS

We addressed this issue using two complementary systems: (1) human skin from patients with diabetic neuropathy and to (2) a coculture model of human dermal fibroblasts (HDFs) with rat dorsal root ganglia neurons in the context of intrinsic neuronal factor and extrinsic microenvironmental collagen and its biosynthetic pathways.

RESULTS

In diabetic neuropathy, the skin innervation of intraepidermal nerve fiber density (IENFd), a measure of sensory nerve degeneration, was reduced with similar expression of a growth associated protein 43, a marker of nerve regeneration. In contrast, the content and packing of collagen in the diabetic skin became more rigid than the control skin. Sec31a, a protein that regulates the collagen biosynthetic pathway, was upregulated and inversely correlated with IENFd. In the cell model, activated HDFs exposed to high-glucose medium enhanced the expression of Sec31a and collagen I through the activation of transforming growth factor β, a profibrotic molecule. Sec31a upregulation impaired neurite outgrowth. This effect was reversed by silencing Sec31a expression and neurite outgrowth was resumed.

INTERPRETATION

The current study provides evidence that Sec31a plays a key role in inhibiting nerve regeneration in diabetic neuropathy. This article is protected by copyright. All rights reserved.

Brain Mechanisms of Pain and Dysautonomia in Diabetic Neuropathy: Connectivity Changes in Thalamus and Hypothalamus

CONTEXT

About one-third of diabetic patients suffer from neuropathic pain, which is poorly responsive to analgesic therapy and associated with greater autonomic dysfunction. Previous research on diabetic neuropathy mainly links pain and autonomic dysfunction to peripheral nerve degeneration resulting from systemic metabolic disturbances, but maladaptive plasticity in the central pain and autonomic systems following peripheral nerve injury has been relatively ignored.

OBJECTIVE

This study aimed to investigate how the brain is affected in painful diabetic neuropathy (PDN), in terms of altered structural connectivity (SC) of the thalamus and hypothalamus that are key regions modulating nociceptive and autonomic responses.

METHODS

We recruited 25 PDN and 13 painless (PLDN) diabetic neuropathy patients, and 27 healthy adults as controls. The SC of the thalamus and hypothalamus with limbic regions mediating nociceptive and autonomic responses was assessed using diffusion tractography.

RESULTS

The PDN patients had significantly lower thalamic and hypothalamic SC of the right amygdala compared with the PLDN and control groups. In addition, lower thalamic SC of the insula was associated with more severe peripheral nerve degeneration, and lower hypothalamic SC of the anterior cingulate cortex was associated with greater autonomic dysfunction manifested by decreased heart rate variability.

CONCLUSION

Our findings indicate that alterations in brain structural connectivity could be a form of maladaptive plasticity after peripheral nerve injury, and also demonstrate a pathophysiological association between disconnection of the limbic circuitry and pain and autonomic dysfunction in diabetes.

Unique Phenotypes With Corresponding Pathology in Late-Onset Hereditary Transthyretin Amyloidosis of A97S vs. V30M

Objective

Hereditary transthyretin amyloidosis (ATTRv) encompasses different phenotypes among various genotypes. The analysis of the natural history and risk factors of faster progression in different genotypes would refine the treatment strategy.

Methods

The clinical manifestations of ATTRv from A97S (p.A117S) of Taiwanese and late-onset V30M (p.V50M) of Japanese were compared. An autopsy study of A97S was performed.

Results

There existed three unique features in the A97S cohort compared to the V30M cohort: (1) dysphagia, (2) carpal tunnel syndrome (CTS), and (3) onset age. First, dysphagia was common in A97S (53.4%) but not in V30M and served as a contributor to fast disease progression. All phases of swallowing were affected. In the autopsy pathology, there were extensive amyloid deposits in the viscera and nerves of the tongue, larynx, and esophagus. In A97S, 45 patients (43.3%) had a history of CTS before the onset of length-dependent symptoms by 3 years. The amyloid deposition was more prominent in the median nerve than that in the transverse carpal ligament. The onset age at different stages was younger in the A97S cohort than the V30M cohort by 4–5 years.

Conclusion

These phenotypic characteristics together with autopsy pathology in A97S are distinct from V30M. Early dysphagia in A97S correlated with fast progression. In A97S, median neuropathy leading to CTS might be in a continuous spectrum of ATTRv course rather than an independent disease entity. Such observations may serve as a foundation to explore and analyze unique phenotypes among various genotypes.

Maladaptive motor cortical excitability and connectivity in polyneuropathy with neuropathic pain

BACKGROUND

Sensory symptoms, especially neuropathic pain, are common in polyneuropathy. Conventional diagnostic tools can evaluate structural or functional impairment of nerves but cannot reveal mechanisms of neuropathic pain. Changes in the brain after polyneuropathy may play roles in the genesis of neuropathic pain.

METHODS

This cross-sectional study investigated changes of cortical excitability within left primary motor cortex (M1) by measuring resting motor thresholds, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), and afferent inhibition between polyneuropathy patients and controls, and investigated the correlates of these parameters with neuropathic pain and the M1 structural and functional connectivity assessed by diffusion tractography imaging and functional MRI.

RESULTS

Thirty-three painful and 15 non-painful neuropathic patients and 21 controls were enrolled. There were no differences in intraepidermal nerve fiber density, nerve conduction study, thermal thresholds, or autonomic functional tests between patients with and without neuropathic pain. Compared to controls, neuropathic patients exhibited similar resting motor thresholds or afferent inhibition, but attenuated SICI and augmented ICF, especially in painful patients. Changes of intracortical excitability in neuropathic patients were correlated with intensities of neuropathic pain, and different presentations of SICI and ICF were noted between patients with and without thermal paresthesia. Additionally, short latency afferent inhibition at interstimulus intervals of 20 ms was associated with structural connectivity of left M1 with brain areas associated with pain perception.

CONCLUSIONS

Maladaptive cortical excitability with altered structural connectivity in left M1 developed after peripheral nerve degeneration and was associated with neuropathic pain and sensory symptoms in polyneuropathy.

Bilateral widespread segmental swelling on nerve sonography in multifocal acquired demyelinating sensory and motor neuropathy: Two case reports

INTRODUCTION

Multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) is an asymmetric immune-related neuropathy with conduction block. We report 2 MADSAM cases with detailed clinical, electrophysiological, and sonography profiles.

PATIENT CONCERNS AND DIAGNOSIS

Two cases presented with patchy sensorimotor impairment in both clinical and electrophysiological findings. Notably, nerve ultrasound demonstrated multifocal nerve enlargement not only at sites of conduction blockade but also at the unaffected contralateral sites. Interestingly, in our first case, focal radial nerve enlargement was observed prior to the clinical manifestations, suggesting nerve dynamic pathogenesis with variable clinical significance.

INTERVENTIONS AND OUTCOMES

The first patient was initially treated with prednisolone, however, 3 months after steroid therapy, her symptoms progressed. After treatment with intravenous immunoglobulin for 3 months, the symptoms stabilized. The second patient showed improvement after 2 months of prednisolone treatment.

CONCLUSION

These observations suggest a more widespread pathomechanism underlying MADSAM, and ultrasound may detect nerve lesions earlier than clinical electrophysiology studies, and is warranted for early detection and thorough documentation of nerve pathology.

Autoantibody of NRIP, a novel AChR-interacting protein, plays a detrimental role in myasthenia gravis

BACKGROUND

Nuclear receptor interaction protein (NRIP) co-localizes with acetylcholine receptor (AChR) at the neuromuscular junction (NMJ), and NRIP deficiency causes aberrant NMJ architecture. However, the normal physiological and pathophysiological roles of NRIP in NMJ are still unclear.

METHODS

We investigated the co-localization and interaction of NRIP with AChR-associated proteins using immunofluorescence and immunoprecipitation assay, respectively. The binding affinity of AChR-associated proteins was analysed in muscle-restricted NRIP knockout mice and NRIP knockout muscle cells (C2C12). We further collected the sera from 43 patients with myasthenia gravis (MG), an NMJ disorder. The existence and features of anti-NRIP autoantibody in sera were studied using Western blot and epitope mapping.

RESULTS

NRIP co-localized with AChR, rapsyn and α-actinin 2 (ACTN2) in gastrocnemius muscles of mice; and α-bungarotoxin (BTX) pull-down assay revealed NRIP with rapsyn and ACTN2 in complexes from muscle tissues and cells. NRIP directly binds with α subunit of AChR (AChRα) in vitro and in vivo to affect the binding affinity of AChR with rapsyn and rapsyn with ACTN2. In 43 patients with MG (age, 58.4 ± 14.5 years; female, 55.8%), we detected six of them (14.0%) having anti-NRIP autoantibody. The presence of anti-NRIP autoantibody correlated with a more severe type of MG when AChR autoantibody existed (P = 0.011). The higher the titre of anti-NRIP autoantibody, the more severe MG severity (P = 0.032). The main immunogenic region is likely on the IQ motif of NRIP. We also showed the IgG subclass of anti-NRIP autoantibody mainly to be IgG1.

CONCLUSIONS

NRIP is a novel AChRα binding protein and involves structural NMJ formation, which acts as a scaffold to stabilize AChR-rapsyn-ACTN2 complexes. Anti-NRIP autoantibody is a novel autoantibody in MG and plays a detrimental role in MG with the coexistence of anti-AChR autoantibody.

Mitochondrial UQCRC1 mutations cause autosomal dominant parkinsonism with polyneuropathy

Parkinson's disease is a neurodegenerative disorder with a multifactorial aetiology. Nevertheless, the genetic predisposition in many families with multi-incidence disease remains unknown. This study aimed to identify novel genes that cause familial Parkinson's disease. Whole exome sequencing was performed in three affected members of the index family with a late-onset autosomal-dominant parkinsonism and polyneuropathy. We identified a novel heterozygous substitution c.941A>C (p.Tyr314Ser) in the mitochondrial ubiquinol-cytochrome c reductase core protein 1 (UQCRC1) gene, which co-segregates with disease within the family. Additional analysis of 699 unrelated Parkinson's disease probands with autosomal-dominant Parkinson's disease and 1934 patients with sporadic Parkinson's disease revealed another two variants in UQCRC1 in the probands with familial Parkinson's disease, c.931A>C (p.Ile311Leu) and an allele with concomitant splicing mutation (c.70-1G>A) and a frameshift insertion (c.73_74insG, p.Ala25Glyfs*27). All substitutions were absent in 1077 controls and the Taiwan Biobank exome database from healthy participants (n = 1517 exomes). We then assayed the pathogenicity of the identified rare variants using CRISPR/Cas9-based knock-in human dopaminergic SH-SY5Y cell lines, Drosophila and mouse models. Mutant UQCRC1 expression leads to neurite degeneration and mitochondrial respiratory chain dysfunction in SH-SY5Y cells. UQCRC1 p.Tyr314Ser knock-in Drosophila and mouse models exhibit age-dependent locomotor defects, dopaminergic neuronal loss, peripheral neuropathy, impaired respiratory chain complex III activity and aberrant mitochondrial ultrastructures in nigral neurons. Furthermore, intraperitoneal injection of levodopa could significantly improve the motor dysfunction in UQCRC1 p.Tyr314Ser mutant knock-in mice. Taken together, our in vitro and in vivo studies support the functional pathogenicity of rare UQCRC1 variants in familial parkinsonism. Our findings expand an additional link of mitochondrial complex III dysfunction in Parkinson's disease.

Early changes of nerve integrity in preclinical carriers of hereditary transthyretin Ala117Ser amyloidosis with polyneuropathy

BACKGROUND AND PURPOSE

Disease-modifying therapies provide new horizons for hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN) to slow neuropathic progression. Initiating treatment at the earliest time requires biomarkers reflecting both small- and large-fiber degeneration in carriers.

METHODS

This study included examinations of pathology (intraepidermal nerve fiber [IENF] density), physiology (nerve conduction studies, autonomic function test, and nerve excitability), and psychophysics (thermal thresholds) in carriers to compare to healthy controls and asymptomatic diabetic patients.

RESULTS

There were 43 carriers (44.2 ± 11.4 years, p.Ala117Ser in 42 carriers), 43 controls (43.4 ± 12.7 years) including 26 noncarrier families, and 50 asymptomatic diabetic patients (58.1 ± 9.5 years). Carriers had lower IENF densities than controls and similar densities as diabetic patients. Median nerve conduction parameters, especially distal motor latency, were the most frequent neurophysiological abnormality in carriers, could differentiate carriers from controls and diabetic patients, were correlated with IENF densities in carriers but not in controls and diabetic patients, and were correlated with nerve excitability parameters in carriers but not in controls. Fifteen carriers (34.9%) with electrophysiological evidence of median nerve entrapment at the wrist had lower IENF densities and more abnormal conduction parameters than carriers without. We defined nerve dysfunction index-the ratio of median distal motor latency to IENF density-which differentiated carriers from controls.

CONCLUSIONS

In late-onset ATTRv-PN carriers with predominant p.Ala117Ser, median conduction parameters were the most common neurophysiological abnormalities and served as surrogate signatures of small- and large-fiber impairment. Combination of median distal motor latency and IENF density can reflect early neuropathy in carriers.

Volume Matters in Ultrasound-Guided Perineural Dextrose Injection for Carpal Tunnel Syndrome: A Randomized, Double-Blinded, Three-Arm Trial

Ultrasound-guided perineural dextrose injection (PDI) has been reported effective for carpal tunnel syndrome (CTS). Higher volume of injectate may reduce adhesion of median nerve from other tissues, but volume-dependent effects of PDI in CTS remain unknown. We aimed to investigate whether PDI with different injectate volumes had different effects for CTS participants. In this randomized, double-blinded, three-arm trial, 63 wrists diagnosed with CTS were randomized into three groups that received ultrasound-guided PDI with either 1, 2 or 4 ml of 5% dextrose water. All participants finished this study. Primary outcome as visual analog scale (VAS) and secondary outcomes including Boston Carpal Tunnel Questionnaire (BCTQ), Disability of the Arm, Shoulder and Hand score (QuickDASH), electrophysiological studies and cross-sectional area (CSA) of the median nerve at carpal tunnel inlet were assessed before and after PDI at the 1st, 4th, 12th and 24th weeks. For within-group analysis, all three groups (21 participants, each) revealed significant improvement from baseline in VAS, BCTQ and QuickDASH at the 1st, 4th, 12th and 24th weeks. For between-group analysis, 4 ml-group yielded better VAS reduction at the 4th and 12th weeks as well as improvement of BCTQ and QuickDASH at the 1st, 4th, and 12th weeks, compared to other groups. No significant between-group differences were observed in electrophysiological studies or median nerve CSA at any follow-up time points. There were no severe complications in this trial, and transient minor adverse effects occurred equally in the three groups. In conclusion, ultrasound-guided PDI with 4 ml of 5% dextrose provided better efficacy than with 1 and 2 ml based on symptom relief and functional improvement for CTS at the 1st, 4th, and 12th week post-injection, with no reports of severe adverse effects. There was no significant difference between the three groups at the 24th-week post-injection follow-up.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT03598322.

Small fiber pathology in autism and clinical implications

OBJECTIVE

To investigate small fiber innervation of the skin and its relationships with clinicometry of autism and peripheral afferents for contact heat-evoked potential (CHEP) and psychophysical measures of thermal thresholds.

METHODS

We recruited 32 men with autism (26.5 ± 5.9 years) and conducted small fiber assessments of skin biopsy with quantifying intraepidermal nerve fiber (IENF) density, CHEP, quantitative sensory testing, and large fiber physiology of nerve conduction studies. Results were compared with age-matched controls and analyzed with clinical measures of autism.

RESULTS

Patients with autism showed a lower IENF density than controls (5.53 ± 2.09 vs 11.13 ± 3.49 fibers/mm, p < 0.0001). The IENF density was reduced in 17 (53.1%) men with autism classified as skin denervation group. On psychophysics, 9 (28%) men with autism had elevated thermal thresholds, and the warm threshold of the big toe was negatively correlated with IENF density (p = 0.0073), indicating functional impairments of small fiber sensory nerves. IENF density was negatively correlated with CHEP amplitude in autism (p = 0.003), in contrast to the pattern of positive correlation in controls, indicating different processing of nociceptive afferent in autism. Clinically, IENF density was related to distinct tactile symptom patterns in the skin denervation vs normal innervation group, respectively. Furthermore, IENF density was associated with autistic symptoms measured by the Autism Spectrum Quotient in a U-shaped model (p = 0.014).

CONCLUSIONS

These observations indicated that a substantial portion of individuals with autism had small fiber pathology, which was associated with tactile and autistic symptoms, providing structural and physiologic evidence for the involvement of peripheral sensory nerves in autism.

A Pilot Study on Serial Nerve Ultrasound in Miller Fisher Syndrome

Objective: Miller Fisher syndrome (MFS) is predominantly a clinical diagnosis, with classic triad of ophthalmoplegia, ataxia, and generalized reduced reflexes. Previous studies in chronic and acute immune-mediated neuropathies indicated that ultrasound, may help to detect changes that could correspond with disease activity. We studied the feasibility of serial nerve ultrasound in MFS, using a healthy controls. Methods: All MFS patients (n = 5) and healthy controls (n = 18), underwent a standardized sonographic protocol that evaluated nerve sizes of facial, large arm and leg nerves, and spinal nerve roots. All MFS patients underwent routine ancillary investigations, including electrodiagnostic testing and for presence of anti-GQ1b antibodies. In addition, four MFS patients had 2nd, and 3rd clinical and sonographic evaluation at 14 and 90 days from onset. Results: The width of the facial nerve was significantly larger in the MFS group than in the control group (MFS: 1.19 ± 0.31 mm vs. normal: 0.67 ± 0.13 mm, P = 0.01). The size of the cervical roots and the nerves in the limbs were similar between the two groups. Two patients' facial nerve size subsided with time, but the decrease in other nerves' sizes were not obvious. Conclusion: Our study showed that serial nerve ultrasound studies are feasible in MFS, and can capture changes in facial nerve size that could complement routine diagnostic tests. Further studies are warranted to determine and compare its test characteristics in MFS.

Skin nerve pathology: Biomarkers of premanifest and manifest amyloid neuropathy

OBJECTIVE

Small-fiber sensory and autonomic symptoms are early presentations of familial amyloid polyneuropathy (FAP) with transthyretin (TTR) mutations. This study aimed to explore the potential of skin nerve pathologies as early and disease-progression biomarkers and their relationship with skin amyloid deposits.

METHODS

Skin biopsies were performed in patients and carriers to measure intraepidermal nerve fiber (IENF) density, sweat gland innervation index of structural protein gene product 9.5 (SGII[PGP9.5]) and peptidergic vasoactive intestinal peptide (SGII[VIP]), and cutaneous amyloid index. These skin pathologies were analyzed with clinical disability assessed by FAP stage score (stage 0-4) and compared to neurophysiological and psychophysical tests.

RESULTS

There were 70 TTR-mutant subjects (22 carriers and 48 patients), and 66 cases were TTR-A97S. Skin nerve pathologies were distinct according to stage. In carriers, both skin denervation and peptidergic sudomotor denervation were evident: (1) IENF density was gradually reduced from stage 0 through 4, and (2) SGII(VIP) was markedly reduced from stage 1 to 2. In contrast, SGII(PGP9.5) was similar between carriers and controls, but it declined in patients from stage 2. Skin amyloids were absent in carriers and became detectable from stage 1. Cutaneous amyloid index was correlated with SGII(PGP9.5) and stage in a multivariate mixed-effect model. When all tests were compared, only IENF density, SGII(PGP9.5), and cutaneous amyloid index were correlated with stage, and IENF density had the highest abnormal rate in carriers.

INTERPRETATION

Biomarkers of sensory and sudomotor innervation exhibited a stage-dependent progression pattern, with sensory nerve degeneration as the early skin nerve pathology. Ann Neurol 2019;85:560-573.

Pathophysiology of Central Poststroke Pain

Background and Purpose—

Central poststroke pain (CPSP) is a disabling condition in stroke patients, and evidence suggests that altered corticospinal and motor intracortical excitability occurs in neuropathic pain. The objective of this study was to investigate changes in motor cortex excitability and sensorimotor interaction and their correlates with clinical manifestations and alterations in somatosensory systems in CPSP patients.

Methods—

Fourteen patients with CPSP but no motor weakness were compared with age- and sex-matched healthy controls for motor cortex excitability and sensorimotor interaction assessed by transcranial magnetic stimulation to measure resting motor thresholds, short-interval intracortical inhibition, intracortical facilitation, and afferent inhibitions. The sensory pathway was evaluated by quantitative sensory testing, contact heat evoked potential, and somatosensory evoked potentials. Clinical pain and quality of life were assessed with validated tools.

Results—

The duration of CPSP was 3.3±3.0 years (ranging 0.5–10 years), and pain significantly impaired quality of life. Compared with the unaffected hemisphere, the stroke hemisphere had higher thermal thresholds, lower contact heat evoked potential amplitudes, and prolonged cortical somatosensory evoked potential latencies. There was no difference in resting motor thresholds between the stroke and unaffected hemisphere or between patients and controls. CPSP patients had a reduction in short-interval intracortical inhibition in the stroke hemisphere compared with that in the unaffected hemispheres of patients and controls. No changes were noted in afferent inhibitions between the stroke and unaffected hemispheres. The short-interval intracortical inhibition of the stroke hemisphere was negatively correlated with self-rated health on a visual analog scale and positively correlated with cortical somatosensory evoked potential latencies.

Conclusions—

CPSP patients with intact corticospinal tracts showed reduced motor intracortical inhibition in the stroke hemisphere, suggesting defective gamma-aminobutyric acid-ergic inhibition. This disinhibition was associated with impaired quality of life and was related to dorsal column–medial lemniscus pathway dysfunction.

Cardiac manifestations and prognostic implications of hereditary transthyretin amyloidosis associated with transthyretin Ala97Ser

BACKGROUND

The cardiac manifestations of late-onset hereditary transthyretin amyloidosis with p.A97S variant have not been extensively studied, and the prognostic factors remain unclear.

METHODS

The clinical profile, echocardiography, and ECG of patients diagnosed with ATTR p.A97S polyneuropathy between 2000 and 2016 were retrospectively collected. 67 patients with ATTR p.A97S were collected.

RESULTS

A total of 82% of patients met the criteria for left ventricular (LV) hypertrophy. Reduced global longitudinal strain (GLS) was noted in 42.1% of patients, and 14% of patients had a relative apical sparing pattern. A low voltage pattern in the ECG was observed in 31.3% of patients, while 64.2% presented with a pseudoinfarction pattern. End-systolic LV inner dimension (HR: 2.25 (95% CI: 1.01-5.01), p = 0.048), reduced GLS (HR: 5.26 (1.08-25.0), p = 0.039), relative apical longitudinal strain (RALS>1, HR: 8.57 (1.69-43.3), p = 0.009), increased E/A ratio (HR: 6.51 (1.17-36.4), p = 0.033), and increased QRS duration (HR: 1.02 (1.00-1.04), p = 0.05) were correlated with reduced survival in univariate analysis. Multivariate analysis revealed reduced RALS was significantly correlated with reduced survival (HR: 13.00 (1.81-93.45), p = 0.011).

CONCLUSION

Our findings reveal that ATTR p.A97S is a cardiomyopathy as well as a polyneuropathic syndrome. Routine use of more contemporary echocardiographic techniques are recommended to identify cardiac amyloidosis and provide prognostic information.

Preimplantation Genetic Diagnosis of Neurodegenerative Diseases: Review of Methodologies and Report of Our Experience as a Regional Reference Laboratory

Preimplantation genetic diagnosis (PGD) has become a crucial approach in helping carriers of inherited disorders to give birth to healthy offspring. In this study, we review PGD methodologies and explore the use of amplification refractory mutation system quantitative polymerase chain reaction (ARMS-qPCR) and/or linkage analysis for PGD in neurodegenerative diseases that are clinically relevant with typical features, such as late onset, and which are severely debilitating. A total of 13 oocyte retrieval cycles were conducted in 10 cases with various neurodegenerative diseases. Among the 59 embryos analyzed, 49.2% (29/59) were unaffected and 50.8% (30/59) were affected. Of the 12 embryo transfer cycles, three resulted in pregnancy, and all pregnancies were delivered. The implantation rate and livebirth rate were 23.1% (3/13) per oocyte retrieval cycle and 25.0% (3/12) per embryo transfer cycle. Allele dropout (ADO) was noted in two embryos that were classified as unaffected by ARMS-qPCR but were evidenced as affected after prenatal diagnosis, rendering the false negative rate as 6.3% (2/32). Four among the 13 cycles underwent PGD by ARMS-qPCR coupled with linkage analysis, and all were correctly diagnosed. We conclude that PGD by ARMS-qPCR and/or linkage analysis is a feasible strategy, whereas ADO is a concern when ARMS-qPCR is used as the sole technology in PGD, especially in autosomal dominant diseases.

Long-term Outcomes After Endovascular Recanalization in Patients with Chronic Carotid Artery Occlusion

Successful carotid artery stenting may correct ipsilateral hemisphere hypoperfusion and improve neurocognitive function in patients with chronic internal carotid artery occlusion (ICAO). Its effect on long-term outcomes, however, has never been studied. From May 2004 to April 2015, endovascular recanalization for chronic ICAO was attempted in 118 consecutive patients (119 lesions; 98 men; 67 ± 10 years old) with either recurrent neurologic events or objectively impaired ipsilateral hemisphere perfusion. Technical success in recanalization was achieved in 70 lesions (59%, 70/119). 3-months cumulative any stroke or death rate was 5% (6/119; 4 in recanalized group, 2 in failure group), including 2 periprocedural ischemic stroke, 2 intracranial hemorrhage, and 2 subarachnoid hemorrhage. In recanalized patients without periprocedural complication, 1-year reocclusion rate was 15% (10/65). Up to 7 years after procedure, cumulative events of transient ischemic attack (TIA), or any stroke, or death were 17 in recanalized group, compared with 23 in failure group (hazard ratio 0.51, 95% confidence interval 0.27 to 0.97; p = 0.04). The difference became more significant after excluding patients with periprocedure events (hazard ratio 0.41, 95% confidence interval 0.20 to 0.84, p = 0.015). In conclusions, the technical success and periprocedural complication rates of endovascular recanalization for chronic ICAO were acceptable. The cumulative event rates of any stroke or death up to 7 years were more favorable in patients after successful recanalization, compared to those in patients after failed procedure.

CD40-mediated HIF-1α expression underlying microangiopathy in diabetic nerve pathology

To understand the pathology and molecular signatures of microangiopathy in diabetic neuropathy, we systemically and quantitatively examined the morphometry of microvascular and nerve pathologies of sural nerves. In the endoneurium of diabetic nerves, prominent microangiopathy was observed, as evidenced by reduced capillary luminal area, increased capillary basement membrane thickness and increased proportion of fibrin(+) blood vessels. Furthermore, capillary basement membrane thickness and the proportion of fibrin(+) blood vessels were correlated with small myelinated fiber density in diabetic nerves. In diabetic nerves, there was also significant macrophage and T cell infiltration, and cluster of differentiation 40 (CD40) expression was increased. The molecular alterations observed were upregulation of hypoxia-inducible factor-1α (HIF-1α), mitogen-activated protein kinase-activated protein kinase 2 (MK2; MAPKAPK2) and phosphatase and tensin homolog (PTEN). In addition, HIF-1α was correlated with small myelinated fiber density and capillary luminal area, while both MK2 and PTEN were correlated with capillary basement membrane thickness. The molecular cascades were further demonstrated and replicated in a cell model of microangiopathy on human umbilical vein endothelial cells (HUVECs) exposed to high-glucose medium by silencing of CD40, PTEN and HIF-1α in HUVECs using shRNA. These data clarified the hierarchy of the molecular cascades, i.e. upregulation of CD40 leading to HIF-1α expression in endothelium and nerve fibers. In conclusion, this study revealed the association of microangiopathy, thrombosis and inflammatory infiltrates with nerve degeneration in diabetic nerves, demonstrating that CD40 is a key molecule for the upregulation of HIF-1α and PTEN underlying the severity of microangiopathy.

Serological evidence of high Leptospira exposure among indigenous people (Orang Asli) in Peninsular Malaysia using a recombinant antigen-based ELISA

The lifestyles of the indigenous people (Orang Asli) of Peninsular Malaysia who traditionally live close to the forest, put them at higher risk of exposure to zoonotic diseases. Leptospirosis has recently emerged as one of the most important diseases of public health concern. Here, we aimed to obtain a baseline data on the level of Leptospira exposure among the 107 Orang Asli volunteers using a recombinant antigen-based ELISA, previously shown to have sensitivity of ~90.0% in comparison to the microscopic agglutination test (MAT). Among the Orang Asli volunteers in this study, 60.7% had IgM against Leptospira and 57.9% were antiLeptospira IgG positive. Of these seropositive individuals, 29.9% had both anti-Leptospira IgM and IgG antibodies. Age was found to be a significant predictor for exposure to Leptospira (P < 0.05) with the younger Orang Asli population more likely to be tested positive for antiLeptospira IgM. The finding of high Leptospira exposure among the Orang Asli volunteers could be due to their socio-economic practices and dependency on the forest for their livelihood. The rapid and sensitive recombinant antigen-based ELISA used in the study, could possibly complement MAT for the epidemiological surveillance of leptospirosis, especially among the underserved populations.

Effective gene expression in the rat dorsal root ganglia with a non-viral vector delivered via spinal nerve injection

Delivering gene constructs into the dorsal root ganglia (DRG) is a powerful but challenging therapeutic strategy for sensory disorders affecting the DRG and their peripheral processes. The current delivery methods of direct intra-DRG injection and intrathecal injection have several disadvantages, including potential injury to DRG neurons and low transfection efficiency, respectively. This study aimed to develop a spinal nerve injection strategy to deliver polyethylenimine mixed with plasmid (PEI/DNA polyplexes) containing green fluorescent protein (GFP). Using this spinal nerve injection approach, PEI/DNA polyplexes were delivered to DRG neurons without nerve injury. Within one week of the delivery, GFP expression was detected in 82.8% ± 1.70% of DRG neurons, comparable to the levels obtained by intra-DRG injection (81.3% ± 5.1%, p = 0.82) but much higher than those obtained by intrathecal injection. The degree of GFP expression by neurofilament(+) and peripherin(+) DRG neurons was similar. The safety of this approach was documented by the absence of injury marker expression, including activation transcription factor 3 and ionized calcium binding adaptor molecule 1 for neurons and glia, respectively, as well as the absence of behavioral changes. These results demonstrated the efficacy and safety of delivering PEI/DNA polyplexes to DRG neurons via spinal nerve injection.

Pathophysiology of Small-Fiber Sensory System in Parkinson's Disease: Skin Innervation and Contact Heat Evoked Potential

Sensory symptoms are frequent nonmotor complaints in patients with Parkinson's disease (PD). However, few investigations integrally explored the physiology and pathology of the thermonociceptive pathway in PD. We aim to investigate the involvement of the thermonociceptive pathway in PD.Twenty-eight PD patients (16 men, with a mean age and standard deviation of 65.6 ± 10.7 years) free of neuropathic symptoms and systemic disorders were recruited for the study and compared to 23 age- and gender-matched control subjects (12 men, with a mean age and standard deviation of 65.1 ± 9.9 years). We performed skin biopsy, contact heat-evoked potential (CHEP), and quantitative sensory tests (QST) to study the involvement of the thermonociceptive pathway in PD.The duration of PD was 7.1 ± 3.2 (range 2-17 years) years and the UPDRS part III score was 25.6 ± 9.7 (range 10-48) during the off period. Compared to control subjects, PD patients had reduced intra-epidermal nerve fiber (IENF) density (2.48 ± 1.65 vs 6.36 ± 3.19 fibers/mm, P < 0.001) and CHEP amplitude (18.02 ± 10.23 vs 33.28 ± 10.48 μV, P < 0.001). Twenty-three patients (82.1%) had abnormal IENF densities and 18 (64.3%) had abnormal CHEP. Nine patients (32.1%) had abnormal thermal thresholds in the feet. In total 27 patients (96.4%) had at least 1 abnormality in IENF, CHEP, or thermal thresholds of the foot, indicating dysfunctions in the small-fiber nerve system. In control subjects, CHEP amplitude linearly correlated with IENF density (P < 0.001). In contrast, this relationship disappeared in PD (P = 0.312) and CHEP amplitude was negatively correlated with motor severity of PD independent of age, gender, and anti-PD medication dose (P = 0.036), suggesting the influences of central components on thermonociceptive systems in addition to peripheral small-fiber nerves in PD.The present study suggested impairment of small-fiber sensory system at both peripheral and central levels is an intrinsic feature of PD, and skin biopsy, CHEP, and QST provided an integral approach for assessing such dysfunctions.

The Temporal Profiles of Changes in Nerve Excitability Indices in Familial Amyloid Polyneuropathy

Familial amyloid polyneuropathy (FAP) caused by a mutation in transthyretin (TTR) gene is an autosomal dominant inherited disorder. The aim of this study is to explore the pathophysiological mechanism of FAP. We prospectively recruited 12 pauci-symptomatic carriers, 18 patients who harbor a TTR mutation, p.A97S, and two-age matched control groups. Data of nerve excitability test (NET) from ulnar motor and sensory axons were collected.NET study of ulnar motor axons of patients shows increased threshold and rheobase, reduced threshold elevation during hyperpolarizing threshold electrotonus (TE), and increased refractoriness. In sensory nerve studies, there are increased threshold reduction in depolarizing TE, lower slope of recovery and delayed time to overshoot after hyperpolarizing TE, increased refractoriness and superexcitability in recovery cycle. NET profiles obtained from the ulnar nerve of carriers show the increase of threshold and rheobase, whereas no significant threshold changes in hyperpolarizing TE and superexcitability. The regression models demonstrate that the increase of refractoriness and prolonged relative refractory period are correlated to the disease progression from carriers to patients. The marked increase of refractoriness at short-width stimulus suggests a defect in sodium current which may represent an early, pre-symptomatic pathophysiological change in TTR-FAP. Focal disruption of basal lamina and myelin may further increase the internodal capacity, manifested by the lower slope of recovery and delayed time to overshoot after hyperpolarization TE as well as the increase of superexcitability. NET could therefore make a pragmatic tool for monitoring disease progress from the very early stage of TTR-FAP.

Quality of life in polyneuropathy: association with biomarkers of small fiber impairment

Background

Polyneuropathy presumably lowers quality of life (QoL). However, there is a lack of systematic studies that assess QoL changes and biomarkers of polyneuropathy as determinants of QoL. We aimed to investigate the relationship between every specific aspect of QoL and the clinical parameters used to assess the impairment of motor, sensory (large and small fibers), and autonomic nerves in polyneuropathy.

Methods

Polyneuropathy patients were recruited from September 2013 to March 2014; QoL was assessed using (1) the WHO Quality of Life-BREF (WHOQoL), (2) the European Quality of Life-5 Dimensions, and (3) the Brief Pain Inventory Short Form. Neuropathy examinations included nerve conduction studies, autonomic function tests, quantitative sensory testing (QST), and intraepidermal nerve fiber (IENF) density assessment of skin biopsies.

Results

There were 61 polyneuropathy patients (male/female = 38/23, mean age 58.14 ± 12.95 years). Patients had a lower QoL than age-and gender-matched controls in the physical and psychological domains of the WHOQoL. Among the biomarkers for different nerve fiber categories, only the small fiber neuropathy assessments were significantly related to all domains of the WHOQoL. In contrast, the parameters of the large fiber neuropathy were independent of QoL. Patients with abnormal temperature thresholds and a lower IENF density had lower WHOQoL scores compared to patients with normal thresholds and IENF densities. Warm threshold of the foot in QST was linearly correlated with all domains of the WHOQoL.

Conclusions

QoL scores were reduced in polyneuropathy, and biomarkers of small fiber neuropathy, i.e., warm threshold and IENF density were discriminating predictors of QoL.

Electronic supplementary material

The online version of this article (doi:10.1186/s12955-015-0363-9) contains supplementary material, which is available to authorized users.

Sudomotor innervation in transthyretin amyloid neuropathy: Pathology and functional correlates

Objective

Autonomic neuropathy is a major component of familial amyloid polyneuropathy (FAP) due to mutated transthyretin, with sudomotor failure as a common manifestation. This study aimed to investigate the pathology and clinical significance of sudomotor denervation.

Methods

Skin biopsies were performed on the distal leg of FAP patients with a follow‐up duration of 3.8 ± 1.6 years. Sudomotor innervation was stained with 2 markers: protein gene product 9.5 (PGP 9.5), a general neuronal marker, and vasoactive intestinal peptide (VIP), a sudomotor nerve functional marker, followed by quantitation according to sweat gland innervation index (SGII) for PGP 9.5 (SGIIPGP 9.5) and VIP (SGIIVIP).

Results

There were 28 patients (25 men) with Ala97Ser transthyretin and late onset (59.9 ± 6.0 years) disabling neuropathy. Autonomic symptoms were present in 22 patients (78.6%) at the time of skin biopsy. The SGIIPGP 9.5 and SGIIVIP of FAP patients were significantly lower than those of age‐ and gender‐matched controls. The reduction of SGIIVIP was more severe than that of SGIIPGP 9.5 (p = 0.002). Patients with orthostatic hypotension or absent sympathetic skin response at palms were associated with lower SGIIPGP 9.5 (p = 0.019 and 0.002, respectively). SGIIPGP 9.5 was negatively correlated with the disability grade at the time of skin biopsy (p = 0.004), and was positively correlated with the interval from the time of skin biopsy to the time of wheelchair usage (p = 0.029).

Interpretation

This study documented the pathological evidence of sudomotor denervation in FAP. SGIIPGP 9.5 was functionally correlated with autonomic symptoms, autonomic tests, ambulation status, and progression of disability. Ann Neurol 2015;78:272℃283