A Sacrifice-for-Survival Mechanism Protects Root Stem Cell Niche from Chilling Stress.

Temperature has a profound influence on plant and animal development, but its effects on stem cell behavior and activity remain poorly understood. Here, we characterize the responses of the Arabidopsis root to chilling (low but above-freezing) temperature. Chilling stress at 4°C leads to DNA damage predominantly in root stem cells and their early descendants. However, only newly generated/differentiating columella stem cell daughters (CSCDs) preferentially die in a programmed manner. Inhibition of the DNA damage response in these CSCDs prevents their death but makes the stem cell niche more vulnerable to chilling stress. Mathematical modeling and experimental validation indicate that CSCD death results in the re-establishment of the auxin maximum in the quiescent center (QC) and the maintenance of functional stem cell niche activity under chilling stress. This mechanism improves the root's ability to withstand the accompanying environmental stresses and to resume growth when optimal temperatures are restored.

Revealing the spatiotemporal brain dynamics of covert speech compared with overt speech: A simultaneous EEG-fMRI study.

Covert speech (CS) refers to speaking internally to oneself without producing any sound or movement. CS is involved in multiple cognitive functions and disorders. Reconstructing CS content by brain-computer interface (BCI) is also an emerging technique. However, it is still controversial whether CS is a truncated neural process of overt speech (OS) or involves independent patterns. Here, we performed a word-speaking experiment with simultaneous EEG-fMRI. It involved 32 participants, who generated words both overtly and covertly. By integrating spatial constraints from fMRI into EEG source localization, we precisely estimated the spatiotemporal dynamics of neural activity. During CS, EEG source activity was localized in three regions: the left precentral gyrus, the left supplementary motor area, and the left putamen. Although OS involved more brain regions with stronger activations, CS was characterized by an earlier event-locked activation in the left putamen (peak at 262 ms versus 1170 ms). The left putamen was also identified as the only hub node within the functional connectivity (FC) networks of both OS and CS, while showing weaker FC strength towards speech-related regions in the dominant hemisphere during CS. Path analysis revealed significant multivariate associations, indicating an indirect association between the earlier activation in the left putamen and CS, which was mediated by reduced FC towards speech-related regions. These findings revealed the specific spatiotemporal dynamics of CS, offering insights into CS mechanisms that are potentially relevant for future treatment of self-regulation deficits, speech disorders, and development of BCI speech applications.

Enhancing EV-cell communication through "External Modulation of Cell by EV" (EMCEV).

Mesenchymal stem/stromal cells (MSC) have displayed promising therapeutic potential. Nonetheless, no United States Food and Drug Administration (FDA)-approved MSC product exists due largely to the absence of a reliable potency assay based on the mechanisms of action to ensure consistent efficacy. MSCs are now thought to exert their effects primarily by releasing small extracellular vesicles (sEVs) of 50-200 nm. While non-living MSC-sEV drugs offer distinct advantages over larger, living MSC drugs, elucidating their mechanism of action to develop robust potency assays remains a challenge. A pivotal prelude to elucidating the mechanism of action for MSC-sEVs is how extracellular vesicles (EVs) engage their primary target cells. Given the inherent inefficiencies of processes such as endocytosis, endosomal escape and EV uncoating during cellular internalization, we propose an alternative EV-cell engagement: EMCEV (Extracellular Modulation of Cells by EV). This approach involves extracellular modulation by EV attributes to generate signaling/inhibitory molecules that have the potential to affect many cells within the vicinity, thereby eliciting a more widespread tissue response.

Engineered EVs with pathogen proteins: promising vaccine alternatives to LNP-mRNA vaccines.

Extracellular vesicles (EVs) are tiny, lipid membrane-bound structures that are released by most cells. They play a vital role in facilitating intercellular communication by delivering bioactive cargoes to recipient cells and triggering cellular as well as biological responses. EVs have enormous potential for therapeutic applications as native or engineered exosomes. Native EVs are naturally released by cells without undergoing any modifications to either the exosomes or the cells that secrete them. In contrast, engineered EVs have been deliberately modified post-secretion or through genetic engineering of the secreting cells to alter their composition. Here we propose that engineered EVs displaying pathogen proteins could serve as promising alternatives to lipid nanoparticle (LNP)-mRNA vaccines. By leveraging their unique characteristics, these engineered EVs have the potential to overcome certain limitations associated with LNP-mRNA vaccines.

Standard Radio-Iodine Labeling Protocols Impaired the Functional Integrity of Mesenchymal Stem/Stromal Cell Exosomes.

Mesenchymal stem/stromal cells (MSCs) are an extensively studied cell type in clinical trials due to their easy availability, substantial ex vivo proliferative capacity, and therapeutic efficacy in numerous pre-clinical animal models of disease. The prevailing understanding suggests that their therapeutic impact is mediated by the secretion of exosomes. Notably, MSC exosomes present several advantages over MSCs as therapeutic agents, due to their non-living nature and smaller size. However, despite their promising therapeutic potential, the clinical translation of MSC exosomes is hindered by an incomplete understanding of their biodistribution after administration. A primary obstacle to this lies in the lack of robust labels that are highly sensitive, capable of directly and easily tagging exosomes with minimal non-specific labeling artifacts, and sensitive traceability with minimal background noise. One potential candidate to address this issue is radioactive iodine. Protocols for iodinating exosomes and tracking radioactive iodine in live imaging are well-established, and their application in determining the biodistribution of exosomes has been reported. Nevertheless, the effects of iodination on the structural or functional activities of exosomes have never been thoroughly examined. In this study, we investigate these effects and report that these iodination methods abrogate CD73 enzymatic activity on MSC exosomes. Consequently, the biodistribution of iodinated exosomes may reflect the biodistribution of denatured exosomes rather than functionally intact ones.

A roadmap from research to clinical testing of mesenchymal stromal cell exosomes in the treatment of psoriasis.

The most clinically trialed cells, mesenchymal stromal cells (MSCs), are now known to mainly exert their therapeutic activity through paracrine secretions, which include exosomes. To mitigate potential regulatory concerns on the scalability and reproducibility in the preparations of MSC exosomes, MSC exosomes were produced using a highly characterized MYC-immortalized monoclonal cell line. These cells do not form tumors in athymic nude mice or exhibit anchorage-independent growth, and their exosomes do not carry MYC protein or promote tumor growth. Unlike intra-peritoneal injections, topical applications of MSC exosomes in a mouse model of IMQ-induced psoriasis alleviate interleukin (IL)-17, IL-23 and terminal complement complex, C5b9 in psoriatic skin. When applied on human skin explants, fluorescence from covalently labeled fluorescent MSC exosomes permeated and persisted in the stratum corneum for about 24 hours with negligible exit out of the stratum corneum into the underlying epidermis. As psoriatic stratum corneums are uniquely characterized by activated complements and Munro microabscesses, we postulated that topically applied exosomes permeate the psoriatic stratum corneum to inhibit C5b9 complement complex through CD59, and this inhibition attenuated neutrophil secretion of IL-17. Consistent with this, we demonstrated that assembly of C5b9 on purified human neutrophils induced IL-17 secretion and this induction was abrogated by MSC exosomes, which was in turn abrogated by a neutralizing anti-CD 59 antibody. We thus established the mechanism of action for the alleviation of psoriatic IL-17 by topically applied exosomes.

MSC-sEV Treatment Polarizes Pro-Fibrotic M2 Macrophages without Exacerbating Liver Fibrosis in NASH.

Mesenchymal stem/stromal cell small extracellular vesicles (MSC-sEVs) have shown promise in treating a wide range of animal models of various human diseases, which has led to their consideration for clinical translation. However, the possibility of contraindication for MSC-sEV use is an important consideration. One concern is that MSC-sEVs have been shown to induce M2 macrophage polarization, which is known to be pro-fibrotic, potentially indicating contraindication in fibrotic diseases such as liver fibrosis. Despite this concern, previous studies have shown that MSC-sEVs alleviate high-fat diet (HFD)-induced non-alcoholic steatohepatitis (NASH). To assess whether the pro-fibrotic M2 macrophage polarization induced by MSC-sEVs could worsen liver fibrosis, we first verified that our MSC-sEV preparations could promote M2 polarization in vitro prior to their administration in a mouse model of NASH. Our results showed that treatment with MSC-sEVs reduced or had comparable NAFLD Activity Scores and liver fibrosis compared to vehicle- and Telmisartan-treated animals, respectively. Although CD163+ M2 macrophages were increased in the liver, and serum IL-6 levels were reduced in MSC-sEV treated animals, our data suggests that MSC-sEV treatment was efficacious in reducing liver fibrosis in a mouse model of NASH despite an increase in pro-fibrotic M2 macrophage polarization.

NOTCH2NLC GGC Repeat Expansions Are Associated with Sporadic Essential Tremor: Variable Disease Expressivity on Long-Term Follow-up.

We screened 662 subjects comprising 462 essential tremor (ET) subjects (285 sporadic, 125 with family history, and 52 probands from well-characterized ET pedigrees) and 200 controls and identified pathogenic NOTCH2NLC GGC repeat expansions in 4 sporadic ET patients. Two patients were followed up for >1 decade; one with 90 repeats remained an ET phenotype that did not evolve after 40 years, whereas another patient with 107 repeats developed motor symptoms and cognitive impairment after 8 to 10 years. Neuroimaging in this patient revealed severe leukoencephalopathy; diffusion-weighted imaging hyperintensity in the corticomedullary junction and skin biopsy revealed intranuclear inclusions suggestive of intranuclear inclusion body disease (NIID). No GGC repeats of >60 units were detected in familial ET cases and controls, although 4 ET patients carried 47 to 53 "intermediate" repeats. NOTCH2NLC GGC repeat expansions can be associated with sporadic ET. Carriers presenting with a pure ET phenotype may or may not convert to NIID up to 4 decades after initial tremor onset. ANN NEUROL 2020;88:614-618.

Topical Application of Mesenchymal Stem Cell Exosomes Alleviates the Imiquimod Induced Psoriasis-Like Inflammation.

Severe psoriasis, a chronic inflammatory skin disease is increasingly being effectively managed by targeted immunotherapy but long-term immunotherapy poses health risk and loss of response. Therefore, there is a need for alternative therapy strategies. Mesenchymal stem/stromal cell (MSC) exosomes are widely known for their potent immunomodulatory properties. Here we investigated if topically applied MSC exosomes could alleviate psoriasis-associated inflammation. Topically applied fluorescent exosomes on human skin explants were confined primarily to the stratum corneum with <1% input fluorescence exiting the explant over a 24-h period. Nevertheless, topically applied MSC exosomes in a mouse model of imiquimod (IMQ) psoriasis significantly reduced IL-17 and terminal complement activation complex C5b-9 in the mouse skin. MSC exosomes were previously shown to inhibit complement activation, specifically C5b-9 complex formation through CD59. Infiltration of neutrophils into the stratum corneum is characteristic of psoriasis and neutrophils are a major cellular source of IL-17 in psoriasis through the release of neutrophil extracellular traps (NETs). We propose that topically applied MSC exosomes inhibit complement activation in the stratum corneum and this alleviates IL-17 release by NETS from neutrophils that accumulate in and beneath the stratum corneum.

Phosphorized CoNi2 S4 Yolk-Shell Spheres for Highly Efficient Hydrogen Production via Water and Urea Electrolysis.

Exploring earth-abundant electrocatalysts with excellent activity, robust stability, and multiple functions is crucial for electrolytic hydrogen generation. Porous phosphorized CoNi2 S4 yolk-shell spheres (P-CoNi2 S4 YSSs) were rationally designed and synthesized by a combined hydrothermal sulfidation and gas-phase phosphorization strategy. Benefiting from the strengthened Ni3+ /Ni2+ couple, enhanced electronic conductivity, and hollow structure, the P-CoNi2 S4 YSSs exhibit excellent activity and durability towards hydrogen/oxygen evolution and urea oxidation reactions in alkaline solution, affording low potentials of -0.135 V, 1.512 V, and 1.306 V (versus reversible hydrogen electrode) at 10 mA cm-2 , respectively. Remarkably, when used as the anode and cathode simultaneously, the P-CoNi2 S4 catalyst merely requires a cell voltage of 1.544 V in water splitting and 1.402 V in urea electrolysis to attain 10 mA cm-2 with excellent durability for 100 h, outperforming most of the reported nickel-based sulfides and even noble-metal-based electrocatalysts. This work promotes the application of sulfides in electrochemical hydrogen production and provides a feasible approach for urea-rich wastewater treatment.

Determinants of quality of life in patients with incurable cancer.

BACKGROUND: Optimizing quality of life (QoL) remains the central tenet of care in patients with incurable cancer; however, determinants of QoL are not clear. The objective of the current study was to examine which factors influence QoL in patients with incurable cancer. METHODS: A multicenter study of adult patients with advanced cancer was conducted in Ireland and the United Kingdom between 2011 and 2016. Data were collected from patients at study entry and included patient demographics, Eastern Cooperative Oncology Group performance status (ECOG-PS), nutritional parameters (the percentage weight loss [%WL]), muscle parameters assessed using computed tomography images (skeletal muscle index and skeletal muscle attenuation), inflammatory markers (modified Glasgow Prognostic score [mGPS]), and QoL data (the European Organization for Research and Treatment Quality-of-Life Questionnaire C-30). The relation between clinical, nutritional, and inflammatory parameters with QoL was assessed using the Spearman rank correlation coefficient and multivariate binary logistic regression. Components of the European Organization for Research and Treatment Quality-of-Life Questionnaire C-30 (physical function, fatigue, and appetite loss) and summary QoL scores were mean-dichotomized for the logistic regression analyses. RESULTS: Data were available for 1027 patients (51% men; median age, 66 years). Gastrointestinal cancer was most prevalent (40%), followed by lung cancer (26%) and breast cancer (9%). Distant metastatic disease was present in 87% of patients. The %WL, ECOG-PS, and mGPS were significantly correlated with deteriorating QoL functional and symptom scales (all P < .001). On multivariate regression analysis, >10% WL (odds ratio [OR], 2.69; 95% CI, 1.63-4.42), an ECOG-PS of 3 or 4 (OR, 14.33; 95% CI, 6.76-30.37), and an mGPS of 2 (OR, 1.58; 95% CI, 1.09-2.29) were independently associated with poorer summary QoL scores. These parameters were also independently associated with poorer physical function, fatigue, and appetite loss (all P < .05). Low skeletal muscle attenuation was independently associated with poorer physical functioning (OR, 1.67; 95% CI, 1.09-2.56), but muscle parameters were not independently associated with fatigue, appetite loss, or QoL summary scores. CONCLUSIONS: The current findings indicate that QoL is determined (at least in part) by WL, ECOG-PS, and the systemic inflammatory response in patients with advanced cancer. Identifying early predictors of poor QoL may allow the identification of patients who may benefit from early referral to palliative and supportive care, which has been shown to improve QoL.

Prognostic factors in patients admitted to an urban teaching hospital with COVID-19 infection.

BACKGROUND: Severe COVID-19 infection results in a systemic inflammatory response (SIRS). This SIRS response shares similarities to the changes observed during the peri-operative period that are recognised to be associated with the development of multiple organ failure. METHODS: Electronic patient records for patients who were admitted to an urban teaching hospital during the initial 7-week period of the COVID-19 pandemic in Glasgow, U.K. (17th March 2020-1st May 2020) were examined for routine clinical, laboratory and clinical outcome data. Age, sex, BMI and documented evidence of COVID-19 infection at time of discharge or death certification were considered minimal criteria for inclusion. RESULTS: Of the 224 patients who fulfilled the criteria for inclusion, 52 (23%) had died at 30-days following admission. COVID-19 related respiratory failure (75%) and multiorgan failure (12%) were the commonest causes of death recorded. Age ≥ 70 years (p < 0.001), past medical history of cognitive impairment (p ≤ 0.001), previous delirium (p < 0.001), clinical frailty score > 3 (p < 0.001), hypertension (p < 0.05), heart failure (p < 0.01), national early warning score (NEWS) > 4 (p < 0.01), positive CXR (p < 0.01), and subsequent positive COVID-19 swab (p ≤ 0.001) were associated with 30-day mortality. CRP > 80 mg/L (p < 0.05), albumin < 35 g/L (p < 0.05), peri-operative Glasgow Prognostic Score (poGPS) (p < 0.05), lymphocytes < 1.5 109/l (p < 0.05), neutrophil lymphocyte ratio (p ≤ 0.001), haematocrit (< 0.40 L/L (male)/ < 0.37 L/L (female)) (p ≤ 0.01), urea > 7.5 mmol/L (p < 0.001), creatinine > 130 mmol/L (p < 0.05) and elevated urea: albumin ratio (< 0.001) were also associated with 30-day mortality. On multivariate analysis, age ≥ 70 years (O.R. 3.9, 95% C.I. 1.4-8.2, p < 0.001), past medical history of heart failure (O.R. 3.3, 95% C.I. 1.2-19.3, p < 0.05), NEWS > 4 (O.R. 2.4, 95% C.I. 1.1-4.4, p < 0.05), positive initial CXR (O.R. 0.4, 95% C.I. 0.2-0.9, p < 0.05) and poGPS (O.R. 2.3, 95% C.I. 1.1-4.4, p < 0.05) remained independently associated with 30-day mortality. Among those patients who tested PCR COVID-19 positive (n = 122), age ≥ 70 years (O.R. 4.7, 95% C.I. 2.0-11.3, p < 0.001), past medical history of heart failure (O.R. 4.4, 95% C.I. 1.2-20.5, p < 0.05) and poGPS (O.R. 2.4, 95% C.I. 1.1-5.1, p < 0.05) remained independently associated with 30-days mortality. CONCLUSION: Age ≥ 70 years and severe systemic inflammation as measured by the peri-operative Glasgow Prognostic Score are independently associated with 30-day mortality among patients admitted to hospital with COVID-19 infection.

MicroRNAs in chronic airway diseases: Clinical correlation and translational applications.

MicroRNAs (miRNAs) are short single-stranded RNAs that have pivotal roles in disease pathophysiology through transcriptional and translational modulation of important genes. It has been implicated in the development of many diseases, such as stroke, cardiovascular conditions, cancers and inflammatory airway diseases. There is recent evidence that miRNAs play important roles in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD), and could help to distinguish between T2-low (non-eosinophilic, steroid-insensitive) versus T2-high (eosinophilic, steroid-sensitive) disease endotypes. As these are the two most prevalent chronic respiratory diseases globally, with rising disease burden, miRNA research might lead to the development of new diagnostic and therapeutic targets. Research involving miRNAs in airway disease is challenging because: (i) asthma and COPD are heterogeneous inflammatory airway diseases; there are overlapping but distinct inter- and intra-disease differences in the immunological pathophysiology, (ii) there exists more than 2000 known miRNAs and a single miRNA can regulate multiple targets, (iii) differential effects of miRNAs could be present in different cellular subtypes and tissues, and (iv) dysregulated miRNA expression might be a direct consequence of an indirect effect of airway disease onset or progression. As miRNAs are actively secreted in fluids and remain relatively stable, they have the potential for biomarker development and therapeutic targets. In this review, we summarize the preclinical data on potential miRNA biomarkers that mediate different pathophysiological mechanisms in airway disease. We discuss the framework for biomarker development using miRNA and highlight the need for careful patient characterization and endotyping in the screening and validation cohorts, profiling both airway and blood samples to determine the biological fluids of choice in different disease states or severity, and adopting an untargeted approach. Collaboration between the various stakeholders - pharmaceutical companies, laboratory professionals and clinician-scientists is crucial to reduce the difficulties and cost required to bring miRNA research into the translational stage for airway diseases.

Using a Steroid-sparing Tool in Paediatric Inflammatory Bowel Disease to Evaluate Steroid Use and Dependency.

OBJECTIVES: The aim of the study was to evaluate the use of steroids within the paediatric inflammatory bowel disease (PIBD) population at a tertiary paediatric centre over a year; to identify cases of steroid dependency; and assess factors associated with steroid excess. METHODS: The prevalent PIBD population (May 1, 2017-April 30, 2018) were reviewed. Data were collected retrospectively from patient records and entered into an online steroid assessment tool (modified for paediatrics). RESULTS: A total of 229 patients (181 Crohn disease, 31 ulcerative colitis [UC], and 17 inflammatory bowel disease-unclassified) were included. Of the 229 patients 38 (16.6%) received oral steroids; 12 of 38 (31.6%) receiving >3-month course. Eleven of 38 (28.9%) received >1 steroid course (maximum 2). Of the 229 patients 37 (16.2%) had exclusive enteral nutrition, with 26 of 37 (11.4% total cohort) avoiding steroid use during the study period.Quiescent disease activity had a negative correlation with steroid use (11/127 [8.7%] vs 27/102 [26.5%] P < 0.01), and steroid dependency (3/127 [2.4%] vs 12/102 [11.8%] P < 0.01). Patients with UC were more likely to be steroid dependent (5/31 [16.1%] UC vs 10/198 [5.1%]; P = 0.02); as were network-managed patients (8/11 [72.7%] vs 7/27 [25.9%]; P = 0.01). Fourteen of 15 (93.3%) of steroid-dependent patients had active steroid sparing strategies in place (eg, commencement, switching, or optimization of therapies). CONCLUSIONS: We have described rates of steroid use and dependency within our PIBD population. Exclusive enteral nutrition served as a steroid sparing tool in 11.4% of the total cohort. Replication of this study in other paediatric centres would allow comparative analysis.

Scope of Hand Surgery Using Surgeon Administered Local/Regional Anaesthesia.

INTRODUCTION: Hand and wrist surgeries are often carried out under local/regional anesthesia. We describe our experience using Surgeon Administered Local/Regional Anaesthesia (SALoRA) without sedation to deliver acute and elective hand surgery anesthesia in a tertiary public hospital in Singapore. This is in comparison to wide awake local anesthesia no tourniquet, which has been increasing in popularity. METHODS: Retrospective analysis was conducted on all surgeries performed under SALoRA between January 1, 2013, to December 31, 2016, at our institution. Surgeries on areas other than the hand, wrist, forearm, and elbow were excluded. The records were reviewed to analyze the demographics of the patients, profile of cases performed, and their outcomes. RESULTS: Of a total of 3016 cases performed, 1994 patients (1275 men; age, 45.78 ± 16 years) fulfilled the inclusion criteria and were available for analysis for the study period. The case distribution was similar to most other published data on day hand surgery cases. Tourniquet was used in 1357 (68%) of cases with an average operation time of 26 ± 19 minutes. Mean tourniquet use was 24 ± 15 minutes. Detailed analysis will be presented. CONCLUSION: This study shows the versatility of SALoRA in delivering hand surgery in a cost-effective manner. A wide spectrum of surgeries in the hand, wrist, forearm, and elbow can be performed using SALoRA safely. This has increased productivity, efficiency, and use of resources. SALoRA has the advantage of a guaranteed and reliable bloodless field, quick turnaround time without the need of extra personnel and resources needed for patient monitoring to abide by Joint Commission International requirements and the potential risk of systemic adrenaline effects.

Simple and Economical Analytical Voltammetry in 15 µL Volumes: Paracetamol Voltammetry in Blood Serum as a Working Example.

Reported is a three-electrode mini-cell for voltammetry in 15 µL solutions. The key device component is a rolled platinum foil of an inverted omega-shaped cross section, which functions as both the electrolyte container and the counter-electrode. The analytical assembly was completed with properly sized working and reference electrodes in the two terminals of the quasi-tubular Pt trough. Its applicability in electrochemical assays of 15 µL solutions was verified by redox mediator voltammetry at graphite and noble metal sensors and by trace lead stripping voltammetry. Real sample analysis was adequate for drug detection in a volunteer's blood, drawn before and 1 or 4 h after ingestion of paracetamol. In line with its known pharmacokinetics, lack of drug as well as drug presence and clearance were proven correctly in the three samples. The mini-cell here is easy to assemble and operate, indefinitely reusable, and offers valuable economy in chemical usage and minimal waste. This is primarily a versatile device for electrochemical laboratory analysis of samples that are available only in small quantities, and cost-effective quantitative screens for expensive high-molecular-weight compounds, products of microsynthesis, physiological microdialysis collections, and finger-prick blood sampling are seen as feasible targets.

An Assessment of Administration Route on MSC-sEV Therapeutic Efficacy.

Mesenchymal stem/stromal cell-derived small extracellular vesicles (MSC-sEVs) are promising therapeutic agents. In this study, we investigated how the administration route of MSC-sEVs affects their therapeutic efficacy in a mouse model of bleomycin (BLM)-induced skin scleroderma (SSc). We evaluated the impact of topical (TOP), subcutaneous (SC), and intraperitoneal (IP) administration of MSC-sEVs on dermal fibrosis, collagen density, and thickness. All three routes of administration significantly reduced BLM-induced fibrosis in the skin, as determined by Masson's Trichrome staining. However, only TOP administration reduced BLM-induced dermal collagen density, with no effect on dermal thickness observed for all administration routes. Moreover, SC, but not TOP or IP administration, increased anti-inflammatory profibrotic CD163+ M2 macrophages. These findings indicate that the administration route influences the therapeutic efficacy of MSC-sEVs in alleviating dermal fibrosis, with TOP administration being the most effective, and this efficacy is not mediated by M2 macrophages. Since both TOP and SC administration target the skin, the difference in their efficacy likely stems from variations in MSC-sEV delivery in the skin. Fluorescence-labelled TOP, but not SC MSC-sEVs when applied to skin explant cultures, localized in the stratum corneum. Hence, the superior efficacy of TOP over SC MSC-sEVs could be attributed to this localization. A comparison of the proteomes of stratum corneum and MSC-sEVs revealed the presence of >100 common proteins. Most of these proteins, such as filaggrin, were known to be crucial for maintaining skin barrier function against irritants and toxins, thereby mitigating inflammation-induced fibrosis. Therefore, the superior efficacy of TOP MSC-sEVs over SC and IP MSC-sEVs against SSc is mediated by the delivery of proteins to the stratum corneum to reinforce the skin barrier.

Contrastive Graph Pooling for Explainable Classification of Brain Networks.

Functional magnetic resonance imaging (fMRI) is a commonly used technique to measure neural activation. Its application has been particularly important in identifying underlying neurodegenerative conditions such as Parkinson's, Alzheimer's, and Autism. Recent analysis of fMRI data models the brain as a graph and extracts features by graph neural networks (GNNs). However, the unique characteristics of fMRI data require a special design of GNN. Tailoring GNN to generate effective and domain-explainable features remains challenging. In this paper, we propose a contrastive dual-attention block and a differentiable graph pooling method called ContrastPool to better utilize GNN for brain networks, meeting fMRI-specific requirements. We apply our method to 5 resting-state fMRI brain network datasets of 3 diseases and demonstrate its superiority over state-of-the-art baselines. Our case study confirms that the patterns extracted by our method match the domain knowledge in neuroscience literature, and disclose direct and interesting insights. Our contributions underscore the potential of ContrastPool for advancing the understanding of brain networks and neurodegenerative conditions. The source code is available at https://github.com/AngusMonroe/ContrastPool.

Contrastive Graph Pooling for Explainable Classification of Brain Networks.

Functional magnetic resonance imaging (fMRI) is a commonly used technique to measure neural activation. Its application has been particularly important in identifying underlying neurodegenerative conditions such as Parkinson's, Alzheimer's, and Autism. Recent analysis of fMRI data models the brain as a graph and extracts features by graph neural networks (GNNs). However, the unique characteristics of fMRI data require a special design of GNN. Tailoring GNN to generate effective and domain-explainable features remains challenging. In this paper, we propose a contrastive dual-attention block and a differentiable graph pooling method called ContrastPool to better utilize GNN for brain networks, meeting fMRI-specific requirements. We apply our method to 5 resting-state fMRI brain network datasets of 3 diseases and demonstrate its superiority over state-of-the-art baselines. Our case study confirms that the patterns extracted by our method match the domain knowledge in neuroscience literature, and disclose direct and interesting insights. Our contributions underscore the potential of ContrastPool for advancing the understanding of brain networks and neurodegenerative conditions. The source code is available at https://github.com/AngusMonroe/ContrastPool.

Hope for vascular cognitive impairment: Ac-YVAD-cmk as a novel treatment against white matter rarefaction.

Vascular cognitive impairment (VCI) is the second leading cause of dementia with limited treatment options, characterised by cerebral hypoperfusion-induced white matter rarefaction (WMR). Subcortical VCI is the most common form of VCI, but the underlying reasons for region susceptibility remain elusive. Recent studies employing the bilateral cortical artery stenosis (BCAS) method demonstrate that various inflammasomes regulate white matter injury and blood-brain barrier dysfunction but whether caspase-1 inhibition will be beneficial remains unclear. To address this, we performed BCAS on C57/BL6 mice to study the effects of Ac-YVAD-cmk, a caspase-1 inhibitor, on the subcortical and cortical regions. Cerebral blood flow (CBF), WMR, neuroinflammation and the expression of tight junction-related proteins associated with blood-brain barrier integrity were assessed 15 days post BCAS. We observed that Ac-YVAD-cmk restored CBF, attenuated BCAS-induced WMR and restored subcortical myelin expression. Within the subcortical region, BCAS activated the NLRP3/caspase-1/interleukin-1beta axis only within the subcortical region, which was attenuated by Ac-YVAD-cmk. Although we observed that BCAS induced significant increases in VCAM-1 expression in both brain regions that were attenuated with Ac-YVAD-cmk, only ZO-1 and occludin were observed to be significantly altered in the subcortical region. Here we show that caspase-1 may contribute to subcortical regional susceptibility in a mouse model of VCI. In addition, our results support further investigations into the potential of Ac-YVAD-cmk as a novel treatment strategy against subcortical VCI and other conditions exhibiting cerebral hypoperfusion-induced WMR.