Commutability evaluation of candidate reference materials and ERM-DA470k/IFCC for immunoglobulin M using two international approaches.

BACKGROUND: This study aimed to assess the commutability of frozen pooled human serum (PHS), high concentration of Immunoglobulin M (IgM) pure diluted materials (HPDM), commercialized pure materials (CPM), and dilutions of ERM-DA470k/IFCC in IgM detection using the CLSI and IFCC approaches, to support standardization or harmonization of IgM measurement. METHODS: Twenty-four serum samples, relevant reference materials (PHS, HPDM, CPM), and different ERM-DA470k/IFCC dilutions were analyzed in triplicate using six routine methods. The commutability of the relevant reference materials was carried out following CLSI EP30-A and IFCC bias analysis. RESULTS: According to the CLSI approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 13, 15, 13, and 8 of 15 assay combinations, respectively. Using the IFCC approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 11, 9, 15, and 10 of 15 assay combinations, respectively. The ERM-DA470k/IFCC dilutions with D-PBS and RPMI-1640 Medium were commutable on 13 of 15 assay combinations according to CLSI and were commutable on all 15 assay combinations using IFCC approach. CONCLUSIONS: High concentration of PHS were commutable on all six detection systems using the CLSI approach. Low and medium concentration of PHS showed unsatisfied commutability. HPDM, not CPM have good commutability, has the potential to become reference materials. ERM-DA470k/IFCC diluted with different medium showed different commutability.

Protective Effect of Nebulized Heparin in the Animal Models of Smoke Inhalation Injury: A Meta-analysis and Systematic Review of Experimental Studies.

The pathophysiological mechanism of abnormal coagulation can result from smoke inhalation injury (SII). Heparin nebulization is a common treatment for lung disorders. This study aimed to use meta-analysis in animal models to examine the effectiveness of atomized heparin on SII. For our online searches, we used the Cochrane Central Register of Controlled Trials, PubMed, Web of Science, Chinese National Knowledge Infrastructure, Chinese BioMedical Literature Database, and Wanfang Database up to January 2022. Data for SII were retrieved and compared to control animals. The studies' findings were determined by combining standardized mean difference (SMD) analysis with 95% confidence intervals (CIs). The findings showed that as compared to the control group, the heparin-treated group had a lower death rate (relative risk 0.42; 95% CI 0.22, 0.80; p < .05). The meta-analysis demonstrated favorable changes in lung physiology, including PaO2/FiO2 (SMD 1.04; 95% CI 0.65, 1.44; p < .001), lung wet-to-dry weight ratio (SMD -1.83; 95% CI -2.47, -1.18; p < .001), and pulmonary shunt Qs/Qt (SMD -0.69; 95% CI -1.29, -0.08; p < .05) after heparin nebulization for lung injury. The present data indicated that pulmonary artery mean pressure in the heparin therapy group was significantly lowered after 24 and 48 hours of therapy, suggesting that the cardiovascular system could recover following heparin treatment. As a result, heparin nebulization appeared to be more effective against SII and improved cardiopulmonary function compared to the control group. Graphical Abstract.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as Idiopathic Pulmonary Fibrosis Microenvironment Targeted Delivery.

Idiopathic pulmonary fibrosis (IPF) affects an increasing number of people globally, yet treatment options remain limited. At present, conventional treatments depending on drug therapy do not show an ideal effect in reversing the lung damage or extending the lives of IPF patients. In recent years, more and more attention has focused on extracellular vesicles (EVs) which show extraordinary therapeutic effects in inflammation, fibrosis disease, and tissue damage repair in many kinds of disease therapy. More importantly, EVs can be modified or used as a drug or cytokine delivery tool, targeting injury sites to enhance treatment efficiency. In light of this, the treatment strategy of mesenchymal stem cell-extracellular vesicles (MSC-EVs) targeting the pulmonary microenvironment for IPF provides a new idea for the treatment of IPF. In this review, we summarized the inflammation, immune dysregulation, and extracellular matrix microenvironment (ECM) disorders in the IPF microenvironment in order to reveal the treatment strategy of MSC-EVs targeting the pulmonary microenvironment for IPF.

Characteristics and Developments in Mesenchymal Stem Cell Therapy for COVID-19: An Update.

The outbreak of coronavirus disease 2019 (COVID-19) has so far resulted in over a hundred million people being infected. COVID-19 poses a threat to human health around the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been confirmed as the pathogenic virus of COVID-19. SARS-CoV-2 belongs to the ß-coronavirus family of viruses and is mainly transmitted through the respiratory tract. It has been proven that SARS-CoV-2 mainly targets angiotensin-converting enzyme II (ACE2) receptors on the surface of various cells in humans. The main clinical symptoms of COVID-19 include fever, cough, and severe acute respiratory distress syndrome (ARDS). Current evidence suggests that the damage caused by the virus may be closely related to the induction of cytokine storms in COVID-19. No specific drugs or measures have yet to be shown to cure COVID-19 completely. Cell-based approaches, primarily mesenchymal stem cells (MSCs), have been identified to have anti-inflammatory and immune functions in COVID-19. Clinical studies about using MSCs and its derivatives-exosomes for COVID-19 treatment-are under investigation. Here, we review the current progress of the biological characteristics, clinical manifestations, and cell-based treatment development for COVID-19. Providing up-to-date information on COVID-19 and potential MSC therapies will help highlight routes to prevent and treat the disease.

Mesenchymal stem cell-derived small extracellular vesicles in the treatment of human diseases: Progress and prospect.

Mesenchymal stem cells (MSCs) are self-renewing, multipotent cells that could differentiate into multiple tissues. MSC-based therapy has become an attractive and promising strategy for treating human diseases through immune regulation and tissue repair. However, accumulating data have indicated that MSC-based therapeutic effects are mainly attributed to the properties of the MSC-sourced secretome, especially small extracellular vesicles (sEVs). sEVs are signaling vehicles in intercellular communication in normal or pathological conditions. sEVs contain natural contents, such as proteins, mRNA, and microRNAs, and transfer these functional contents to adjacent cells or distant cells through the circulatory system. MSC-sEVs have drawn much attention as attractive agents for treating multiple diseases. The properties of MSC-sEVs include stability in circulation, good biocompatibility, and low toxicity and immunogenicity. Moreover, emerging evidence has shown that MSC-sEVs have equal or even better treatment efficacies than MSCs in many kinds of disease. This review summarizes the current research efforts on the use of MSC-sEVs in the treatment of human diseases and the existing challenges in their application from lab to clinical practice that need to be considered.

RNA aptamers as conformational probes and regulatory agents for plasminogen activator inhibitor-1.

The hallmark of serpins is the ability to undergo the so-called "stressed-to-relaxed" switch during which the surface-exposed reactive center loop (RCL) becomes incorporated as strand 4 in central beta-sheet A. RCL insertion drives not only the inhibitory reaction of serpins with their target serine proteases but also the conversion to the inactive latent state. RCL insertion is coupled to conformational changes in the flexible joint region flanking beta-sheet A. One interesting serpin is plasminogen activator inhibitor-1 (PAI-1), a fast and specific inhibitor of the serine proteases tissue-type and urokinase-type plasminogen activator. Via its flexible joints' region, native PAI-1 binds vitronectin and relaxed, protease-complexed PAI-1 certain endocytosis receptors. From a library of 35-nucleotides long 2'-fluoropyrimidine-containing RNA oligonucleotides, we have isolated two aptamers binding PAI-1 by the flexible joint region with low nanomolar K(D) values. One of the aptamers exhibited measurable binding to native PAI-1 only, while the other also bound relaxed PAI-1. While none of the aptamers inhibited the antiproteolytic effect of PAI-1, both aptamers inhibited vitronectin binding and the relaxed PAI-1-binding aptamer also endocytosis receptor binding. The aptamer binding exclusively to native PAI-1 increased the half-life for the latency transition to more than 6 h, manyfold more than vitronectin. Contact with Lys124 in the flexible joint region was critical for strong inhibition of the latency transition and the lack of binding to relaxed PAI-1. We conclude that aptamers yield important information about the serpin conformational switch and, because they can compete with high-affinity protein-protein interactions, may provide leads for pharmacological intervention.

Enzymatic synthesis of chitosan-gelatin antimicrobial copolymer and its characterisation.

BACKGROUND: Schiff bases can be formed by reaction between acylamino and the amino group with microbial transglutaminase (MTGase) as catalyst and used in protein crosslinking in the food industry. A novel chitosan-gelatin copolymer for coating meat products can be synthesised using MTGase as catalyst, with the characteristics of both chitosan and gelatin. The aim of the present study was to synthesise and characterise chitosan-gelatin antimicrobial copolymer. RESULTS: The yield of copolymer increased with increasing gelatin/chitosan ratio, while bacteriostasis of Staphylococcus aureus by the copolymer decreased, showing that its bacteriostatic ability depended on the amino group in chitosan. Under optimal synthesis conditions of 50 degrees C, pH 6 and 40 min reaction time the copolymer yield was 64.5% at a gelatin/chitosan ratio of 0.6. Bacteriostasis of S. aureus by 10 g kg(-1) copolymer solution was 70% of that by chitosan. CONCLUSION: A novel biological dressing frame material with excellent biocompatibility and antibacterial properties has been successfully prepared. The results of this study provide a background for further investigation of potential applications of chitosan-gelatin copolymer in the areas of agriculture and food.

Otoprotective effects of ethosuximide in NOD/LtJ mice with age-related hearing loss.

Despite long-term efforts to elucidate the mechanisms responsible for age-related hearing loss (AHL), there is currently no available treatment strategy able to provide a cure. Apoptotic cell death, including that of hair cells and spiral ganglion neurons (SGNs) in the cochlea has been proposed to be the classic theory behind the development of AHL. As calcium signaling plays key roles in signal transduction in apoptosis, in this study, we selected ethosuximide, which is able to block T-type calcium (Ca2+ion) channels, suppressing Ca2+. We hypothesized that the apoptotic pathway may be blocked through the inhibition of T-type Ca2+ channels in cochlear cells in NOD/LtJ mice. NOD/LtJ mice were divided into 2 groups as follows: the ethosuximide-treated and untreated (control) groups. Ethosuximide was administered by intraperitoneal injection every other day from post-natal day seven (P7) until the mice were 8 weeks of age. Following treatment, auditory-evoked brainstem response (ABR) thresholds and distortion product oto-acoustic emission (DPOAE) of the mice in the 2 groups were measured at different time points. Morphometric analysis and the expression of genes involved in the T-type Ca2+-mediated apoptotic pathway were monitored. The ABR and DPOAE results revealed that the NOD/LtJ mice exhibited early-onset and rapidly progressive AHL. A histological examination revealed that hair cell degeneration coincided with the progression of hearing loss. Hair cell and SGN was were significantly lower and auditory function was significantly improved in the ethosuximide-treated group compared to the untreated group. Our data thus indicate that ethosuximide prevents the degeneration of cochlear cells by regulating the expression of genes in apoptotic pathways. Our findings suggest that activating the T-type Ca2+ channel and downstream genes may be key pathological mechanisms responsible for AHL in NOD/LtJ mice.

Otitis media induced by peptidoglycan-polysaccharide (PGPS) in TLR2-deficient (Tlr2(-/-)) mice for developing drug therapy.

BACKGROUND: Toll like receptor 2 (TLR2) signaling can regulate the pathogenesis of otitis media (OM). However, the precise role of TLR2 signaling in OM has not been clarified due to the lack of an optimal animal model. Peptidoglycan-polysaccharide (PGPS) of the bacterial cell wall can induce inflammation by activating the TLR2 signaling. This study aimed at examining the pathogenic characteristics of OM induced by PGPS in Tlr2(-/-) mice, and the potential therapeutic effect of sodium aescinate (SA) in this model. METHODS: Wild-type (WT) and Tlr2(-/-) mice were inoculated with streptococcal PGPS into their middle ears (MEs) and treated intravenously with vehicle or SA daily beginning at 3days prior to PGPS for 6 consecutive days. The pathologic changes of individual mice were evaluated longitudinally. RESULTS: In comparison with WT mice, Tlr2(-/-) mice were susceptible to PGPS-induced OM. Tlr2(-/-) mice displayed greater hearing loss, tympanic membrane damage, ME mucosal thickening, longer inflammation state, cilia and goblet cell loss. SA-treatment decreased neutrophil infiltration, modulated TLR2-related gene expression and improved ciliary organization. CONCLUSIONS: PGPS induced a relatively stable OM in Tlr2(-/-) mice, providing a new model for OM research. Treatment with SA mitigated the pathogenic damage in the ME and may be valuable for intervention of OM.