Granzyme K- and amphiregulin-expressing cytotoxic T cells and activated extrafollicular B cells are potential drivers of IgG4-related disease

BACKGROUND

IgG4-related disease (IgG4-RD), an example of a type I immune disease, is an immune-mediated fibrotic disorder characterized by dysregulated resolution of severe inflammation and wound healing. However, truly dominant or pathognomonic autoantibodies related to IgG4-RD are not identified.

OBJECTIVE

We sought to perform single-cell RNA sequencing and T-cell receptor and B-cell receptor sequencing to obtain a comprehensive, unbiased view of tissue-infiltrating T and B cells.

METHODS

We performed unbiased single-cell RNA-sequencing analysis for the transcriptome and T-cell receptor sequencing and B-cell receptor sequencing on sorted CD3+ T or CD19+ B cells from affected tissues of patients with IgG4-RD. We also conducted quantitative analyses of CD3+ T-cell and CD19+ B-cell subsets in 68 patients with IgG4-RD and 30 patients with Sjögren syndrome.

RESULTS

Almost all clonally expanded T cells in these lesions were either Granzyme K (GZMK)-expressing CD4+ cytotoxic T cells or GZMK+CD8+ T cells. These GZMK-expressing cytotoxic T cells also expressed amphiregulin and TGF-β but did not express immune checkpoints, and the tissue-infiltrating CD8+ T cells were phenotypically heterogeneous. MKI67+ B cells and IgD-CD27-CD11c-CXCR5- double-negative 3 B cells were clonally expanded and infiltrated affected tissue lesions. GZMK+CD4+ cytotoxic T cells colocalized with MKI67+ B cells in the extrafollicular area from affected tissue sites.

CONCLUSIONS

The above-mentioned cells likely participate in T-B collaborative events, suggesting possible avenues for targeted therapies. Our findings were validated using orthogonal approaches, including multicolor immunofluorescence and the use of comparator disease groups, to support the central role of cytotoxic CD4+ and CD8+ T cells expressing GZMK, amphiregulin, and TGF-β in the pathogenesis of inflammatory fibrotic disorders.

Single-cell transcriptomics reveals granzyme K-expressing cytotoxic Tfh cells in tertiary lymphoid structures in IgG4-RD

BACKGROUND

Germinal center (GC) responses controlled by T follicular helper (Tfh) and T follicular regulatory (Tfr) cells are crucial for the generation of high-affinity antibodies. Acquired immune responses to tissue-released antigens might be mainly induced in tertiary lymphoid organs (TLOs) with GCs in affected tissues. IgG4-related disease (IgG4-RD) demonstrates polarized isotype switching and TLOs in affected tissues. We performed single-cell transcriptomics of tissue-infiltrating T cells from these TLOs to obtain a comprehensive, unbiased view of tissue-infiltrating GC-Tfh cells.

OBJECTIVE

To identify GC-Tfh-cell subsets in TLOs in patients with IgG4-RD using single-cell transcriptomics.

METHODS

Single-cell RNA sequencing of sorted CD3+ T cells and multicolor immunofluorescence analysis were used to investigate CD4+CXCR5+Bcl6+ GC-Tfh cells in affected lesions from patients with IgG4-RD.

RESULTS

Infiltrating CD4+CXCR5+Bcl6+ Tfh cells were divided into 5 main clusters. We detected HLA+ granzyme K+ (GZMK+) Tfh cells with cytotoxicity-associated features in patients with IgG4-RD. We also observed abundant infiltrating Tfr cells with suppressor-associated features in patients with IgG4-RD. These GZMK+ Tfh cells and Tfr cells clustered together in affected tissues from patients with IgG4-RD.

CONCLUSIONS

This single-cell data set revealed a novel subset of HLA+GZMK+ cytotoxic Tfh cells infiltrating affected organs in patients with IgG4-RD, suggesting that infiltrating Tfr cells might suppress cytotoxic Tfh cells.

Predicting Patient Status in Chronic Thromboembolic Pulmonary Hypertension Using a Biophysical Model

Chronic thromboembolic pulmonary hypertension (CTEPH) involves abnormally high blood pressure in the pulmonary vessels and is associated with small vessel vasculopathy and pre-capillary proximal occlusions. Management of CTEPH disease is challenging, therefore accurate diagnosis is crucial in ensuring effective treatment and improved patient outcomes. The treatment of choice for CTEPH is pulmonary endarterectomy, which is an invasive surgical intervention to remove thrombi. Following PEA, a number of patients experience poor outcomes or worse-than-expected improvements, which may indicate that they have significant small vessel disease. A method that can predict the extent of distal remodelling may provide useful clinical information to plan appropriate CTEPH patient treatment. Here, a novel biophysical modelling approach has been developed to estimate and quantify the extent of distal remodelling. This method includes a combination of mathematical modelling and computed tomography pulmonary angiography to first model the geometry of the pulmonary arteries and to identify the under-perfused regions in CTEPH. The geometric model is then used alongside haemodynamic measurements from right heart catheterisation to predict distal remodelling. In this study, the method is tested and validated using synthetically generated remodelling data. Then, a preliminary application of this technique to patient data is shown to demonstrate the potential of the approach for use in the clinical setting.Clinical relevance- Patient-specific modelling can help provide useful information regarding the extent of distal vasculopathy on a per-patient basis, which remains challenging. Physicians can be unsure of outcomes following pulmonary endarterectomy. Therefore, the predictive aspect of the patient's response to surgery can help with clinical decision-making.

Whole body vibration accelerates the functional recovery of motor nerve components in sciatic nerve-crush injury model rats

This study aimed to investigate the effect of whole body vibration (WBV) on the sensory and motor nerve components with sciatic nerve injury model rats. Surgery was performed on 21 female Wister rats (6-8 weeks) under intraperitoneal anesthesia. The nerve-crush injuries for the left sciatic nerve were inflicted using a Sugita aneurysm clip. The sciatic nerve model rats were randomly divided into two groups (n=9; control group, n=12; WBV group). The rats in the WBV group walked in the cage with a vibratory stimulus (frequency 50 Hz, 20 min/day, 5 times/wk), while those in the control group walked in the cage without any vibratory stimulus. We used heat stimulation-induced sensory threshold and lumbar magnetic stimulation-induced motor-evoked potentials (MEPs) to measure the sensory and motor nerve components, respectively. Further, morphological measurements, bilateral hind-limb dimension, bilateral gastrocnemius dimension, and weight were evaluated. Consequently, there were no significant differences in the sensory threshold at the injury side between the control and WBV groups. However, at 4 and 6 weeks postoperatively, MEPs latencies in the WBV group were significantly shorter than those in the control group. Furthermore, both sides of the hind-limb dimension at 6 weeks postoperatively, the left side of the gastrocnemius dimension, and both sides of the gastrocnemius weight significantly increased. In conclusion, WBV especially accelerates the functional recovery of motor nerve components in sciatic nerve-crush injury model rats.

Short-Term Collagen Nerve Wrapping Facilitates Motor and Sensory Recovery from Nerve Degeneration in a Sciatic Nerve Injury Rat Model

Purpose

This study used a sciatic nerve injury rat model to investigate the short-term effects of a polyglycolic acid (PGA)-collagen tube for nerve injury in continuity.

Materials and Methods

Sixteen female Wistar rats (6-8 weeks) were used, and the left sciatic nerve was crushed with a Sugita aneurysm clip. Sciatic nerve model rats were randomly categorized into two groups (n = 8; control group, n = 8; nerve wrapping group). Then, we measured four sensory thresholds, magnetically stimulated the lumbar region to induce motor-evoked potentials (MEPs), and evaluated the sciatic nerve histopathologically.

Results

In the sensory thresholds, there were significant differences for the main effect in 250 and 2000 Hz stimulation (p = 0.048 and 0.006, respectively). Further, a significant difference was observed with 2000 Hz stimulation at 1 week (p = 0.003). In the heat stimulation, there were significant differences for the main effect in both weeks and groups (p = 0.0002 and 0.0185, respectively). The post-hoc test showed a significant difference between groups only in 2W (p = 0.0283). Three weeks after the surgery, both 2nd and 3rd MEPs waves-related latencies in the nerve wrapping group were significantly shorter than those in the control group (p = 0.0207 and 0.0271, respectively). Histological evaluation of the sciatic nerve revealed considerable differences in the number of axons between the two groups (p = 0.0352).

Conclusion

The short-term PGA-collagen tube nerve wrapping facilitated motor and sensory recovery from nerve degeneration in the sciatic nerve injury rat model.

Prediction of clinical outcomes in patients with coronavirus disease 2019 using high-sensitive troponin I and N-terminal pro-B-type natriuretic peptide

Background

Several comorbidities, including cardiovascular diseases or myocardial injury, are reported to be associated with poor prognosis in patients with Coronavirus disease 2019 (COVID-19). However, detailed prognostic analysis of myocardial injury by various biomarkers in COVID-19 patients is limited.

Purpose

This study aims to explore the prognostic values of high-sensitive Troponin I (hsTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) for COVID-19 patients using Japanese real-world data.

Methods

The COVID-MI study is a retrospective cohort study that enrolls consecutive laboratory-confirmed COVID-19 patients admitted to the hospital from July 2020 to September 2021. We collected clinical data, including cardiac biomarker values, by chart review. If the prespecified biomarkers in concern were not available, we measured them using the institutional serum blood bank, which enrolled patients prospectively from July 2020. Patients with available biomarkers were analyzed according to the values of hsTnI or NT-proBNP, using the clinically relevant thresholds (hsTnI: 5 ng/L and 99th percentile of the upper reference limit [99%ile URL], and NT-proBNP: 125 pg/mL and 900 pg/mL). The primary outcome measure was all-cause death. Secondary outcome measures included acute respiratory distress syndrome, myocardial infarction, myocarditis/pericarditis, venous thromboembolism, cerebral infarction, and bleeding events.

Results

We enrolled 917 patients with COVID-19 confirmed by viral nucleic acid amplification test. The mean age was 61 years, and 591 patients (64%) were men. On admission, the number of patients classified as severe or critical COVID-19 was 515 (56%) and 85 (8.7%), respectively. Among the 544 patients with hsTnI values, 365 (67%) patients had elevated hsTnI of ≥5 ng/L, and 134 patients (25%) had TnI of ≥99%ile URL. Besides, among 546 patients with NT-proBNP values, 295 patients (54%) had elevated NT-pro-BNP of ≥125 pg/mL, and 93 patients (17%) had NT-proBNP of ≥900 pg/mL. The median follow-up period was 31 days (interquartile range: 11–90 days). In cumulative incidence analysis, higher levels of hsTnI and NT-proBNP were associated with significantly higher mortality (hsTnI: <5 ng/L group; 8.8%, 5 ng/L to 99%ile URL group; 19%, and ≥99%ile URL group; 37%, P<0.001, and NT-proBNP: <125 pg/mL group; 7.8%, 125 to 900 pg/mL group; 21%, and ≥900 pg/mL group; 45%, P<0.001). The adjusted risk for all-cause death remained significant for each threshold of cardiac biomarkers (hsTnI ≥99%ile URL: hazard ratio [HR] 1.98, 95% confidence interval [CI] 1.11–3.54, P=0.02, and NT-proBNP ≥900 pg/mL: HR 3.60, 95% CI 1.86–6.98, P<0.001).

Conclusion

Elevation of hsTnI or NT-proBNP was associated with poor prognosis in the current relatively severely ill COVID-19 patients. Measuring hsTnI or NT-proBNP can be an attractive option for risk stratification and deciding appropriate management in patients with COVID-19.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Institutional Research Fund at Kobe City Medical Center General Hospital

Distinct disease-specific Tfh cell populations in two different fibrotic diseases: IgG4-related disease and Kimura's disease

BACKGROUND

How T follicular (Tfh) cells contribute to many different B-cell class-switching events during T cell-dependent immune responses has been unclear. Diseases with polarized isotype switching offer a unique opportunity for the exploration of Tfh subsets. Secondary and tertiary lymphoid organs (SLOs and TLOs) in patients with elevated tissue expression levels of IgE (Kimura's disease, KD) and those of IgG4 (IgG4-related disease, IgG4-RD) can provide important insights regarding cytokine expression by Tfh cells.

OBJECTIVE

To identify disease-specific Tfh cell subsets in SLOs and TLOs expressing IL-10 or IL-13 and thus identify different cellular drivers of class switching in two distinct types of fibrotic disorders: allergic fibrosis (driven by type 2 immune cells) and inflammatory fibrosis (driven by cytotoxic T lymphocytes).

METHODS

Single-cell RNA-sequencing, in situ sequencing, and multi-color immunofluorescence analysis was used to investigate B cells, Tfh cells and infiltrating type 2 cells in lesion tissues from patients with KD or IgG4-RD.

RESULTS

Infiltrating Tfh cells in TLOs from IgG4-RD were divided into six main clusters. We encountered abundant infiltrating IL-10-expressing LAG3⁺ Tfh cells in patients with IgG4-RD. Furthermore, we found that infiltrating AID⁺CD19⁺B cells expressing IL-4, IL-10, and IL-21 receptors correlated with IgG4 expression. In contrast, we found that infiltrating IL-13-expressing Tfh cells were abundant in affected tissues from patients with KD. Moreover, we observed few infiltrating IL-13-expressing Tfh cells in tissues from patients with IgG4-RD, despite high serum levels of IgE (but low IgE in the disease lesions). Cytotoxic T cells were abundant in IgG4-RD, and in contrast Type 2 immune cells were abundant in KD.

CONCLUSIONS

This single-cell dataset revealed a novel subset of IL10⁺LAG3⁺Tfh cells infiltrating the affected organs of IgG4-RD patients. In contrast, IL13⁺Tfh cells and type 2 immune cells infiltrated those of KD patients.

Unusual response to atrial entrainment pacing dependent on pacing current strength: What is the mechanism?

A 77-year-old woman with palpitations was referred for a second radiofrequency ablation for persistent atrial tachycardia (AT). This article is protected by copyright. All rights reserved.

A novel perfusion culture system for screening mitochondrial toxicity in primary mouse hepatocytes

The liver microphysiological system (MPS) model is an in-vitro culture method that mimics physiological blood flow, which enhances basal cellular functions. However, the liver MPS model has not been tested in the preclinical stage because of its obscure utility. It can overcome the major problem of conventional systems-rapid loss of mitochondrial activity in cultured hepatocytes due to limited oxygen supply-by supplying oxygen to cultured hepatocytes using a perfusion device. In this study, we developed a new perfusion culture system that can detect mitochondrial toxicity. Primary mouse hepatocytes were cultured under perfusion condition for 48 hr. The hepatocytes showed increased oxygen consumption and reduced lactate release. These results indicated that the ATP-production pathway was switched from glycolysis to mitochondrial oxidative phosphorylation in the perfusion culture system. Furthermore, ATP levels were considerably reduced in the perfusion culture system after exposure to phenformin, a mitochondrial complex I inhibitor. To summarize, the perfusion culture system could improve the mitochondrial activity in primary mouse hepatocytes, and thus, has potential implications in the detection of mitochondrial toxicity.

A successful case of "temporary endoluminal bypass technique" using a guide extension catheter during thrombolysis for acute limb ischemia in the non-stenting zone

It is still difficult to treat acute limb ischemia (ALI) in the non-stenting zone such as the popliteal artery. We describe a temporary endoluminal bypass technique for ALI in the non-stenting zone using a guide extension catheter. An 83-year-old female was admitted and diagnosed with ALI in her left leg. The angiogram showed a thrombotic obstruction of the left popliteal artery. Aspiration and dilation by angioplasty could not revascularize. Although Fogarty thrombectomy can be applicable, we avoided it because of its risk of complications and performed a temporary endoluminal bypass technique. After evaluating the occluded lesion by intravascular ultrasound, we delivered a guide extension catheter to fully cover it. Because it played the role of an endoluminal bypass, the blood flow to the distal tibial arteries could be confirmed in the angiogram. A thrombolytic drug was administered intra-arterially for the whole day, and the angiogram showed a reduction of the thrombus on postoperative day (POD) 1. On POD 2, the blood flow was maintained without flow limitation even after removing the catheter. Finally, she was discharged without any complications. This technique might be an alternative in cases of failed conventional treatments for ALI although further investigation needs to be undertaken. <Learning objective: Although endovascular treatment (EVT) has recently been developed, revascularization for acute limb ischemia (ALI) in the non-stenting zone such as popliteal artery has remained the unsolved problem. We report temporary endoluminal bypass technique for ALI in the non-stenting zone using a guide extension catheter. This technique can prevent limb ischemia during thrombolysis. When the conventional EVT procedures fail, it can be an alternative for ALI in the non-stenting zone.>.

Identification of hub molecules of FUS-ALS by Bayesian gene regulatory network analysis of iPSC model: iBRN

Fused in sarcoma/translated in liposarcoma (FUS) is a causative gene of amyotrophic lateral sclerosis (ALS). Mutated FUS causes accumulation of DNA damage and cytosolic stress granule (SG) formation, thereby motor neuron (MN) death. However, key molecular aetiology remains unclear. Here, we applied a novel platform technology, iBRN, "Non- biased" Bayesian gene regulatory network analysis based on induced pluripotent stem cell (iPSC)-derived cell model, to elucidate the molecular aetiology using transcriptome of iPSC-derived MNs harboring FUS^H517D. iBRN revealed "hub molecules", which strongly influenced transcriptome network, such as miR-125b-5p-TIMELESS axis and PRKDC for the molecular aetiology. Next, we confirmed miR-125b-5p-TIMELESS axis in FUS^H517D MNs such that miR-125b-5p regulated several DNA repair-related genes including TIMELESS. In addition, we validated both introduction of miR-125b-5p and knocking down of TIMELESS caused DNA damage in the cell culture model. Furthermore, PRKDC was strongly associated with FUS mis-localization into SGs by DNA damage under impaired DNA-PK activity. Collectively, our iBRN strategy provides the first compelling evidence to elucidate molecular aetiology in neurodegenerative diseases.

Impact of a poor functional capacity on the clinical outcomes in patients with a pacemaker implantation -Results from the Japanese Heart Rhythm Society Registry

BACKGROUND

Functional capacity (FC) correlates with mortality in various cardiovascular diseases. The aim of this study was to examine whether cardiac pacemaker implantations improve the FC and affect the prognosis.

METHODS AND RESULTS

We prospectively enrolled 621 de novo pacemaker recipients (age 76 ± 9 years, 50.7% male). The FC was assessed by metabolic equivalents (METs) during the implantation and periodically thereafter. The patients were a priori classified into poor FC (<2 METs, n = 40), moderate FC (2 ≤ METs < 4, n = 239), and good FC (≥4 METs, n = 342). Three months after the pacemaker implantation, poor FC or moderate FC patients improved to a good FC by 43%. The distribution of the three FCs remained at those levels until after 1 year of follow-up (P = .18). During a median follow-up of 2.4 years, 71 patients (11%) had cardiovascular hospitalizations and 35 (5.6%) all-cause death. A multivariate Cox analysis revealed that a poor FC at baseline was an independent predictor of both cardiovascular hospitalization (hazard ratio [HR] 2.494, P = .012) and all-cause death (HR 3.338, P = .016). One year after the pacemaker implantation, the eight who remained with a poor FC had a high mortality rate of 37.5% (P < .01).

CONCLUSION

Approximately half of the poor or moderate FC patients improved to good FC 3 months after the pacemaker implantation. The baseline FC predicted the prognosis, and patients with an improved FC after the pacemaker implantation had a better prognosis.

Elucidation of EEG Characteristics of Fuzzy Reasoning-Based Heuristic BCI and Its Application to Patient With Brain Infarction

Non-invasive brain–computer interfaces (BCIs) based on common electroencephalography (EEG) are limited to specific instrumentation sites and frequency bands. These BCI induce certain targeted electroencephalographic features of cognitive tasks, identify them, and determine BCI's performance, and use machine-learning to extract these electroencephalographic features, which makes them enormously time-consuming. In addition, there is a problem in which the neurorehabilitation using BCI cannot receive ambulatory and immediate rehabilitation training. Therefore, we proposed an exploratory BCI that did not limit the targeted electroencephalographic features. This system did not determine the electroencephalographic features in advance, determined the frequency bands and measurement sites appropriate for detecting electroencephalographic features based on their target movements, measured the electroencephalogram, created each rule (template) with only large “High” or small “Low” electroencephalograms for arbitrarily determined thresholds (classification of cognitive tasks in the imaginary state of moving the feet by the size of the area constituted by the power spectrum of the EEG in each frequency band), and successfully detected the movement intention by detecting the electroencephalogram consistent with the rules during motor tasks using a fuzzy inference-based template matching method (FTM). However, the electroencephalographic features acquired by this BCI are not known, and their usefulness for patients with actual cerebral infarction is not known. Therefore, this study clarifies the electroencephalographic features captured by the heuristic BCI, as well as clarifies the effectiveness and challenges of this system by its application to patients with cerebral infarction.

Absence of shock therapy related to improper sensing of noise on the defibrillation test during subcutaneous implantable cardioverter-defibrillator implantation: a case report

Background 

Subcutaneous implantable cardioverter–defibrillator (S-ICD) represents an efficient alternative to transvenous ICD in patients who do not require pacing. The intraoperative defibrillation test (DFT) is recommended during S-ICD implantation to confirm appropriate sensing and successful 65-J termination of induced ventricular fibrillation (VF). However, few cases of oversensing of noise inhibiting therapies have been reported.

Case summary 

We report the case of a 50-year-old man who underwent S-ICD implantation for secondary prevention of sudden cardiac death. Immediately after S-ICD implantation, VF was induced using a 50-Hz burst; however, shock was not delivered owing to sustained noise on the electrogram in the primary vector. Therefore, an external rescue shock was needed at 150 J. We changed the sensing vector from primary to secondary and performed a second DFT. The S-ICD could deliver an appropriate shock and was able to successfully terminate VF without noise markers in the secondary vector. During the second DFT, one back-up pacing was delivered after the shock; the sensing vector then automatically switched from the secondary to the alternate vector. However, noise was observed in the alternate vector despite sinus rhythm restoration.

Discussion 

The present case demonstrated that noise was recorded in two different vectors during DFT, possibly supporting the hypothesis that the muscle spasm of the diaphragm induced by the 50-Hz burst causes oversensing of noise by the S-ICD.

Comparison of Immunohistochemical Staining for Large T Antigen and Capsid Protein VP1 in BK Polyomavirus-Associated Nephropathy

AIM

Most transplant centres use SV40 large T antigen (TAg) staining for the diagnosis and assessment of BK polyomavirus-associated nephropathy (BKPyVAN). This study was performed to evaluate the significance of capsid protein VP1 expression in BKPyVAN.

METHODS

We performed immunohistochemical staining using anti-SV40 TAg and anti-BKPyV VP1 antibodies in 16 index biopsies and 12 re-biopsies of BKPyVAN and compared the patterns of positivity and the percentage of positive tubules by counting whole specimens. We investigated the correlation between serum creatinine increase from baseline and the percentage of positive tubules for both markers in 16 index biopsies.

RESULTS

In VP1 staining, positive findings were observed not only in the nuclei of tubular epithelial cells but also in the cytoplasm, cells shedding into the lumen, intra-tubular casts, and in the interstitium. Two of 28 biopsies (7.1%) showed TAg-positive and VP1-negative results, in which TAg-positive cells were detected only in a single tubule. The median (interquartile range) percentage of positive tubules was 2.8% (0.7-9.8%) for TAg and 1.4% (0.5-3.9%) for VP1 staining (p = 0.2). In 16 index biopsies, serum creatinine increases significantly correlated with the percentage of VP1-positive tubules (r = 0.49, p = 0.02), while this correlation revealed borderline significance with TAg-positive tubules.

CONCLUSIONS

VP1 expression showed various patterns, but was detected in half as many tubules as TAg staining, which might lead to false negatives in the samples with minimal viral replication. However, increased VP1-positive tubules indicate advanced tubular damage and possible association with graft dysfunction.

Free gait in a shallow pool accelerates recovery after exercise in model mice with fibromyalgia

This study aimed to determine the effect of pool gait exercise using fibromyalgia-induced model mice. The sensory threshold, locomotive behavior, electrocardiogram, and onset time after the gait test in shallow water using male C57BL/6J mice (weight, 30–35 g; n=21) were investigated. To induce fibromyalgia in model mice, reserpine was injected intraperitoneally into wild-type mice once a day for 3 days. Subsequently, the fibromyalgia-induced model mice were randomly classified into two groups as follows: the control group (n=11) and the pool gait group (n=10). The mice in the pool gait group walked in the same cage containing shallow warm water 5 times per week. Both groups underwent sensory thresholds and video recordings to determine locomotive behaviors weekly. Further, both heart rate and video recordings for observation of a recovery after the gait test in shallow water were undertaken (control group; n=5, pool gait group; n=5). The pool gait did not affect sensory thresholds and locomotive behavior; however, in the pool gait group, both the recovery after the test, such as onset time and gait distance, were considerably better than those of the control group. Furthermore, changes in heart rate and heart rate irregularity after the test were more apparent in the control group than in the pool gait group. The free gait in a shallow pool accelerated recovery after exercise, unlike the sensory threshold.

Excessive exercise induces cardiac arrhythmia in a young fibromyalgia mouse model

Background

Fibromyalgia patients experience cardiovascular complications in addition to musculoskeletal pain. This study aimed to investigate the cardiac effects of a prolonged shallow water gait in a fibromyalgia-induced young mouse model.

Methods

To produce a fibromyalgia mouse model, wild-type mice were administered an intraperitoneal injection of reserpine once a day for three days, and two primary experiments were performed. First, three types of gait tests were performed before and after the reserpine injections as follows: (i) 5 minutes of free gait outside the water, (ii) 1 minute of free gait in shallow warm water, and (iii) 5 minutes of free gait in shallow warm water. Second, electrocardiogram recordings were taken before and after the three gait tests. The average heart rate and heart rate irregularity scores were analyzed.

Results

Exercise-induced cardiac arrhythmia was observed at 1-minute gait in shallow water during the acute stage of induced FM in young mice. Further, both cardiac arrhythmia and a decrease in HR have occurred at 5-minute gait in shallow water at the same mice. However, this phenomenon was not observed in the wild-type mice under any test conditions.

Conclusion

Although a short-term free gait in shallow warm water may be advantageous for increasing the motor activity of FM-model mice, we should be aware of the risk of prolonged and excessive exercise-induced cardiac arrhythmia. For gait exercises in shallow water as a treatment in FM patients. We suggest a gradual increase in exercise duration may be warranted.

Ca2+ -independent and voltage-dependent exocytosis in mouse chromaffin cells

AIM

It is widely accepted that the exocytosis of synaptic and secretory vesicles is triggered by Ca²⁺ entry through voltage-dependent Ca²⁺ channels. However, there is evidence of an alternative mode of exocytosis induced by membrane depolarization but lacking Ca²⁺ current and intracellular Ca²⁺ increase. In this work we investigated if such a mechanism contributes to secretory vesicle exocytosis in mouse chromaffin cells.

METHODS

Exocytosis was evaluated by patch-clamp membrane capacitance measurements, carbon fibre amperometry and TIRF. Cytosolic Ca²⁺ was estimated using epifluorescence microscopy and fluo-8 (salt form).

RESULTS

Cells stimulated by brief depolatizations in absence of extracellular Ca⁺² show moderate but consistent exocytosis, even in presence of high cytosolic BAPTA concentration and pharmacological inhibition of Ca⁺² release from intracellular stores. This exocytosis is tightly dependent on membrane potential, is inhibited by neurotoxin Bont-B (cleaves the v-SNARE synaptobrevin), is very fast (saturates with time constant <10 ms), it is followed by a fast endocytosis sensitive to the application of an anti-dynamin monoclonal antibody, and recovers after depletion in <5 s. Finally, this exocytosis was inhibited by: (i) ω-agatoxin IVA (blocks P/Q-type Ca²⁺ channel gating), (ii) in cells from knock-out P/Q-type Ca²⁺ channel mice, and (iii) transfection of free synprint peptide (interferes in P/Q channel-exocytic proteins association).

CONCLUSION

We demonstrated that Ca²⁺ -independent and voltage-dependent exocytosis is present in chromaffin cells. This process is tightly coupled to membrane depolarization, and is able to support secretion during action potentials at low basal rates. P/Q-type Ca²⁺ channels can operate as voltage sensors of this process.

Prognostic value of high-sensitive troponin T for predicting cardiovascular events after atrial fibrillation ablation

BACKGROUND AND OBJECTIVES

This study aimed to evaluate the utility of high-sensitive troponin T (hs-TnT) for predicting AF recurrence and major adverse cardiovascular events (MACE) after AF ablation.

METHODS AND RESULTS

A total of 227 consecutive patients with AF (mean age, 66 ± 10 years; persistent AF, n = 98) who underwent an initial ablation were enrolled. We measured hs-TnT before AF ablation and divided the patients into three groups according to the hs-TnT level: low, lesser than or equal to 0.005 µg/L (n = 54); medium, 0.006-0.013 µg/L (n = 127); and high, greater than or equal to0.014 µg/L (n = 46). We evaluated the composite endpoint of AF recurrence or MACE (including death, stroke, acute coronary syndrome, and heart failure hospitalization) after the ablation. The median hs-TnT level was 0.008 µg/L. The values of chronic kidney disease prevalence, CHA₂ DS₂ -VASc score, B-type natriuretic peptide level, and left atrial diameter were the highest in the high hs-TnT group among the three groups. During a mean follow-up of 15 ± 8 months, AF recurrence and MACE occurred in 56 (25%) and 9 (4%) patients, respectively. The high hs-TnT group had the highest incidence of AF recurrence and MACE among the three groups (high: 39% and 15%, medium: 22% and 2%, and low: 19% and 0%, respectively; log-rank P < .05). In multivariate analysis, hs-TnT greater than or equal to 0.014 µg/L and persistent AF were independent predictors of the composite endpoint.

CONCLUSION

Hs-TnT may be a useful marker for predicting AF recurrence or MACE after AF ablation.

Noradrenaline modulates mechanically evoked responses in the rat spinal dorsal horn: an in vivo patch-clamp study

Purpose: We investigated the effects of noradrenaline (NA) on physiologically evoked synaptic responses of substantia gelatinosa (SG) neurons using anesthetized animals.

Methods: Male Sprague–Dawley rats (6–8 weeks, 200–300 g, n=21) were anesthetized. The lumbar spinal cord was exposed from L3 to L5; subsequently, the rats were fixed to a stereotaxic apparatus. The electrode was advanced at an angle of 30–45 degrees into the SG using a micromanipulator. We recorded excitatory post-synaptic currents (EPSC). Under these conditions, innocuous or noxious mechanical stimuli were applied to the receptive field of the ipsilateral hindlimb with or without NA, respectively.

Results: NA (50 μM) pre-application induced three types of responses for pinch-evoked EPSCs. The number of neurons showing inhibition, facilitation, and no-effect was 15 (71.4%), 2 (9.5%), and 4 (19%), respectively (n=21). Pre-treatment with NA also induced three different types of responses for puff-evoked EPSC (n=21). The number of neurons showing inhibition, facilitation, and no-effect was 9 (42.9%), 9 (42.9%), and 3 (14.2%), respectively. Further, there was a significant difference in the rate distribution (inhibition, facilitation, and no change) between puff- and pinch-evoked responses.

Conclusion: Our present data indicate that NA acts on noxious and innocuous mechanical transmission in the SG. Considering the distinct sensory inputs to the SG, the different actions of NA on the transmission of sensory information imply that NA exerts its analgesic effects in a manner more complicated than previously believed.

Recumbent cycling with integrated volitional control electrical stimulation improves gait speed during the recovery stage in stroke patients

The purpose of this study was to investigate the effect of recumbent cycling with integrated volitional control electrical stimulation (IVES) on gait ability in stroke patients. Six stroke patients (all male; average age, 55.7±8.3 years) participated. Recumbent cycling (R-cycling) was performed with and without IVES in the power assist (IVES-P) mode. The targeted muscle for electrostimulation was the tibialis anterior. Patients performed 10 min of IVES-P mode plus R-cycling (program A) or R-cycling alone (program B), once per day, 5 times per week. Patients completed two sets of each program, alternating between programs each week. Gait speed and the number of steps numbers on a 10-m walking test was assessed before and after each interventional session. Program A improved gait speed, but not the number of steps, to a greater extent than that in program B. Specifically, the combined intervention significantly improved gait speed in the first set, but not the second set of the intervention. R-cycling with IVES-P mode improved gait speed during the recovery stage in stroke patients to a greater extent than that achieved with R-cycling alone. Thus, this combined therapy has potential as a standardized treatment in the field of rehabilitation medicine.

Autoantibodies to killer cell immunoglobulin-like receptor 3DL1 in patients with systemic lupus erythematosus

A genetic variant of the killer immunoglobulin-like receptor 3DL1 (KIR3DL1) has been found in patients with systemic lupus erythematosus (SLE). Herein, we investigated the presence of autoantibodies to KIR3DL1 in a cohort of patients with SLE. We tested sera from 28 patients with SLE, 11 patients with rheumatoid arthritis (RA) and 17 healthy control subjects for anti-KIR3DL1 activity by an enzyme-linked immunosorbent assay (ELISA) using recombinant KIR3DL1-enhanced green fluorescent protein (EGFP) and EGFP proteins. Anti-KIR3DL1 antibodies were detected in 22 (79%) of the 28 patients with SLE, whereas they were present in only three (27%) of the 11 patients with RA examined. Notably, 10 (91%) of the 11 samples from patients with SLE prior to therapy had anti-KIR3DL1 antibodies. None of the samples from healthy donors were positive for the antibodies. Here, we report the presence of anti-KIR3DL1 antibodies in the sera of patients with SLE for the first time. Anti-KIR3DL1 autoantibodies may be involved in the pathogenesis of autoimmune diseases.

Right ventricular enlargement predicts responsiveness to tolvaptan in congestive heart failure patients with reduced ejection fraction

Background

Tolvaptan is a vasopressin type 2 receptor antagonist used in heart failure (HF) with refractory diuretic resistance. However, since tolvaptan is also ineffective in some HF patients with reduced ejection fraction (HFrEF), the identification of responders is important.

Methods

The study population consisted of 51 HFrEF patients who were administered tolvaptan (EF, 28 ± 7%). We defined responders as patients with a ≥50% increase in urine volume during the 24-hours after administration of tolvaptan. All patients underwent comprehensive transthoracic echocardiography before administration of tolvaptan. Patients were followed for 120 days to ascertain secondary events (cardiac death and rehospitalization for HF).

Results

Multiple regression analysis indicated that right ventricular (RV) enlargement (defined as basal RV diameter > 41 mm and midlevel RV diameter > 35 mm, according to guidelines) remained a predictor of response after adjustment for age, sex, starting dosage of tolvaptan, and estimated glomerular filtration rate (odds ratio, 4.88; 95%-confidence interval, 1.26–18.9; P < 0.05), whereas left ventricular parameters and RV dysfunction were not. Kaplan-Meier curves indicated responsiveness to tolvaptan was associated with better prognosis among the overall population (P < 0.05); similar trends were observed among patients with RV dilatation (P = 0.056).

Conclusions

These findings suggest that RV enlargement, which represents right-sided volume overload, elevated filling pressure, and diastolic dysfunction similar to that seen in constrictive pericarditis, predicts responsiveness to tolvaptan in patients with HFrEF. Moreover, administration of tolvaptan may have the potential to improve the reportedly poor prognosis for HFrEF patients with RV dilatation.

Both ipsilateral and contralateral localized vibratory stimulations modulated pain-related sensory thresholds on the foot in mice and humans

Purpose

This study was aimed to investigate the effect of localized vibration on sensory thresholds in mice and humans using a novel quantitative method.

Participants and methods

The sensory thresholds of 7-week-old male C57BL/6J mice were measured with four sine-wave electrostimulation frequencies (5, 50, 250, and 2,000 Hz) before and after applying 2-minute vibration to the plantar side of the foot in mice. In human participants (16 males and 16 females; mean age, 21.0±0.8 years), the sensory threshold was measured at 50 Hz before and after applying 2-minute and 5-minute vibrations to the dorsal side of the foot.

Results

Application of a 2-minute vibration at either the ipsilateral or contralateral side modulated the sensory thresholds elicited by a 5- or 50-Hz right electrostimulation in mice. In human participants, application of a 5-minute vibration at either the ipsilateral or contralateral side modulated the sensory threshold elicited by 50-Hz right electrostimulation, but had no effect on local skin temperature. These results suggest that the right side of pain-related Aδ fibers (50 Hz) or C fibers (5 Hz) was modulated by the localized ipsilateral or contralateral side of vibratory stimuli, respectively, in mice and humans.

Conclusion

The ability of contralateral vibration to modify the right sensory thresholds suggests possible involvement of the central nervous system in vibratory modulation.

The clinical impact of human T-lymphotrophic virus type 1 (HTLV-1) infection on the development of adult T-cell leukemia-lymphoma (ATL) or HTLV-1-associated myelopathy (HAM) / atypical HAM after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and renal transplantation

Because there are limited clinical reports on the impact of human T-lymphotropic virus type 1 (HTLV-1) on organ transplantation, its effects on the development of adult T-cell leukemia-lymphoma (ATL), post-transplantation lymphoproliferative disorder (PTLD) and HTLV-1–associated myelopathy (HAM) or atypical HAM after organ transplantation remain unclear.

We retrospectively analyzed the impact of HTLV-1 in 54 allogeneic hematopoietic stem cell transplantation (allo-HSCT) cases and 31 renal transplantation cases between January 2006 and December 2016.

Among the 54 allo-HSCT cases, nine recipients with ATL tested positive for HTLV-1, and one was found to be an HTLV-1 carrier. All donors tested negative for HTLV-1. Only one HTLV-1 carrier did not present with ATL or HAM development after allo-HSCT. Among nine ATL cases after allo-HSCT, four eventually relapsed due to proliferation of recipient-derived ATL cells. However, in one ATL case, atypical HAM developed rapidly at 5 months after allo-HSCT.

Among the 31 renal transplantation cases, all donors tested negative for HTLV-1, and only recipients tested positive. Only one HTLV-1 carrier recipient did not present with ATL or HAM development after renal transplantation. However, one HTLV-1-negative recipient developed PTLD in the brain 10 years after renal transplantation.

In clinical practice, careful follow-up of HTLV-1 infected recipients after organ transplantation is important because atypical HAM can develop in ATL patients after allo-HSCT. Furthermore, to clarify the risk of ATL or HAM development in HTLV-1 infected recipients, we prospectively followed up our cohort.

Thrombotic microangiopathy associated with anticardiolipin antibody in a kidney transplant recipient with polycythemia

Thrombotic microangiopathy (TMA) develops from various etiologies, and it is often difficult to distinguish the etiology of TMA in kidney transplantation. Antiphospholipid syndrome (APS) is one of the differential diagnoses for TMA that may cause acute loss of graft function or fatal thrombotic complications. This report details a 66-year-old male patient with polycythemia after ABO-incompatible kidney transplantation. Antibody screening tests were negative before transplant. Despite administration of an adequate desensitization therapy including plasmapheresis and rituximab, he developed acute graft dysfunction on postoperative day 112 and graft biopsy revealed prominent microvascular inflammation in the glomerular capillaries without immunoglobulin deposits. Flow cytometric panel-reactive antibody screening failed to detect donor-specific antibodies at both pre-transplant and episode biopsies. Anticardiolipin antibody was repeatedly positive, but neither thrombosis nor previous thrombotic episodes were detected. After excluding several differential diagnoses, the graft dysfunction with unexplained TMA was treated with steroid pulse, plasmapheresis and rituximab re-induction. Anticardiolipin antibody disappeared after this intensive treatment and graft function recovered gradually and stabilized for 52 months. This report suggests that asymptomatic anticardiolipin antibody may be associated with acute graft dysfunction. Even if thrombotic episodes are not observed, an exist of anticardiolipin antibody may be one of the risk factors of renal TMA after kidney transplantation.

Greater nighttime blood pressure variability is associated with left atrial enlargement in atrial fibrillation patients with preserved ejection fraction

Left atrial enlargement is an independent risk factor for ischemic stroke in patients with atrial fibrillation. Little is known regarding the association between nighttime blood pressure variability and left atrial enlargement in patients with atrial fibrillation and preserved ejection fraction. The study population consisted of 140 consecutive patients with atrial fibrillation (mean age 64 ± 10 years) with preserved ejection fraction (≥50%). Nighttime blood pressure was measured at hourly intervals, using a home blood pressure monitoring device. Nighttime blood pressure variability was expressed as the standard deviation of all readings. Left atrial volume index was measured using the modified Simpson's biplane method with transthoracic echocardiography. Multiple regression analysis indicated that nighttime mean systolic/diastolic blood pressure and its variability remained independently associated with left atrial enlargement after adjustment for age, sex, anti-hypertensive medication class, and left ventricular mass index (P < 0.01). When patients were divided into four groups according to nighttime blood pressure and its variability, the group with higher nighttime blood pressure and its variability had significantly larger left atrial volume than the group with lower nighttime blood pressure and its variability (46.6 ml/m² vs. 35.0 ml/m², P < 0.0001). Higher nighttime blood pressure and its variability are associated with left atrial enlargement. The combination of nighttime blood pressure and its variability has additional predictive value for left atrial enlargement. Intensive intervention for these high-risk patients may avoid or delay progression of left atrial enlargement and reduce the risk of stroke.

Shorter duration of antibiotic treatment for acute bacteraemic cholangitis with successful biliary drainage: a retrospective cohort study

OBJECTIVES

To assess the effectiveness of short duration antimicrobial therapy for acute cholangitis with bacteraemia.

METHODS

We conducted a retrospective cohort study of patients with acute bacteraemic cholangitis with successful biliary duct drainage at a single centre in Japan. We compared short-course antimicrobial therapy (SCT, ≤7 days) and long-course therapy (LCT, ≥8 days), with a primary outcome of 30-day mortality. We constructed logistic regression models for mortality and a composite outcome, including mortality, recurrence, recrudescence, new bacteraemia, liver abscess or other complications related to cholangitis. We also developed a propensity score for SCT with inverse probability weighting for both the primary outcome and the composite outcome.

RESULTS

We identified 263 patients in our cohort; 86 (32.7%) patients received SCT and the remaining 177 (67.3%) received LCT. The median durations of SCT and LCT were 6 days (range 2-7 days) and 12 days (range 8-46 days), respectively. The 30-day mortalities of SCT and LCT were 4.7% (4/85) and 5.7% (10/176), respectively (p 1.00). Logistic regression analysis showed that the odds ratio of SCT for 30-day mortality and the composite outcome were 1.07 (95% CI 0.25-4.52, p 0.93) and 1.08 (95% CI 0.48-2.45, p 0.85), respectively. Propensity score analyses for both 30-day mortality and the composite outcome did not demonstrate a difference between SCT and LCT (p 0.65 and p 0.95, respectively).

CONCLUSIONS

SCT with a median duration of 6 days did not have worse outcomes than LCT with a median duration of 12 days. Shortening the duration of antimicrobial therapy may be a reasonable option when treating acute bacteraemic cholangitis following successful biliary drainage.

Multiple coronary artery spasms triggering life-threatening ventricular arrhythmia associated with the radiofrequency ablation of ganglionated plexuses of the left atrium

We report a case of multiple coronary spasms leading to life-threatening ventricular arrhythmia, during left atrium (LA) ablation. Coronary artery spasm is a rare complication during radiofrequency catheter ablation of atrial fibrillation (AF). Previous reports mention that autonomic imbalance leads to coronary artery spasm and ST-segment elevation in the inferior leads, during trans-septal LA catheterization and AF ablation procedures. However, there are few reports detailing the association between ablation sites and changes in the electrocardiogram. We encountered transient ST-segment elevation and refractory ventricular arrhythmia, associated with coronary artery spasm, during radiofrequency ablation of ganglionated plexuses (superior surface of left and right atrium). <Learning objective: Our case report shows that ablation of ganglionated plexus sites during pulmonary vein isolation, can induce ST-segment elevation in various leads, and cause multiple coronary spasms associated with refractory ventricular fibrillation. There is an inherent risk of multiple coronary spasms during catheter ablation of atrial fibrillation (AF), in patients with vasospastic angina. We recommend continuous intravenous infusion of nitroglycerin during ablation for AF to prevent coronary spasms in patients with vasospastic angina.>.

High-resolution imaging in two-photon excitation microscopy using in situ estimations of the point spread function

We present a technique for improving the spatial resolution of two-photon excitation microscopy; our technique combines annular illumination with an in situ estimation of the point spread function (PSF) used for deconvolution. For the in situ estimation of the PSF, we developed a technique called autocorrelation scanning, in which a sample is imaged by the scanning of two excitation foci that are overlapped over various distances. The image series obtained with the variation of the distance between the two foci provides the autocorrelation function of the PSF, which can be used to estimate the PSF at specific positions within a sample. We proved the principle and the effectiveness of this technique through observations of a fluorescent biological sample, and we confirmed that the improvement in the spatial resolution was ~1.7 times that of typical two-photon excitation microscopy by observing a mouse brain phantom at a depth of 200 µm.