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Osteoporosis (OP) is a common and complex chronic metabolic disease with an increasing incidence rate, which has markedly increased the human health burden worldwide. The predominant cause of OP is an imbalance between osteoblasts (OB) and osteoclasts (OC). Studies on the correlation between bone marrow-derived mesenchymal stem cells (BMSCs) and OP have indicated that BMSCs-induced OB differentiation is an important pathway for bone tissue renewal. Chinese medicinal herbs have been used for centuries to treat various types of OPs because they are safer and more effective. The in vivo and in vitro experiments have confirmed that these herbs or their primary phytochemicals may exert therapeutic effects by stimulating BMSCs differentiation, which restores OB and OP balance, inhibits adipocyte differentiation, exerts anti-inflammatory and antioxidant effects, regulates the immune system, etc. This review summarizes the research on how Chinese medicinal herbs or their primary phytochemicals treat OP by stimulating BMSC differentiation and provides a scientifically reliable basis and perspective for their future clinical application.
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Glutamate is traditionally viewed as the first messenger to activate NMDAR (N-methyl-D-aspartate receptor)-dependent cell death pathways in stroke1,2, but unsuccessful clinical trials with NMDAR antagonists implicate the engagement of other mechanisms3-7. Here we show that glutamate and its structural analogues, including NMDAR antagonist L-AP5 (also known as APV), robustly potentiate currents mediated by acid-sensing ion channels (ASICs) associated with acidosis-induced neurotoxicity in stroke4. Glutamate increases the affinity of ASICs for protons and their open probability, aggravating ischaemic neurotoxicity in both in vitro and in vivo models. Site-directed mutagenesis, structure-based modelling and functional assays reveal a bona fide glutamate-binding cavity in the extracellular domain of ASIC1a. Computational drug screening identified a small molecule, LK-2, that binds to this cavity and abolishes glutamate-dependent potentiation of ASIC currents but spares NMDARs. LK-2 reduces the infarct volume and improves sensorimotor recovery in a mouse model of ischaemic stroke, reminiscent of that seen in mice with Asic1a knockout or knockout of other cation channels4-7. We conclude that glutamate functions as a positive allosteric modulator for ASICs to exacerbate neurotoxicity, and preferential targeting of the glutamate-binding site on ASICs over that on NMDARs may be strategized for developing stroke therapeutics lacking the psychotic side effects of NMDAR antagonists.
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Canales Iónicos Sensibles al Ácido , Isquemia Encefálica , Ácido Glutámico , Animales , Femenino , Humanos , Masculino , Ratones , 2-Amino-5-fosfonovalerato/efectos adversos , 2-Amino-5-fosfonovalerato/metabolismo , 2-Amino-5-fosfonovalerato/farmacología , Canales Iónicos Sensibles al Ácido/química , Canales Iónicos Sensibles al Ácido/deficiencia , Canales Iónicos Sensibles al Ácido/efectos de los fármacos , Canales Iónicos Sensibles al Ácido/genética , Canales Iónicos Sensibles al Ácido/metabolismo , Regulación Alostérica/efectos de los fármacos , Sitios de Unión/genética , Isquemia Encefálica/inducido químicamente , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Ácido Glutámico/análogos & derivados , Ácido Glutámico/metabolismo , Ácido Glutámico/farmacología , Ácido Glutámico/toxicidad , Ratones Noqueados , Mutagénesis Sitio-Dirigida , Protones , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/metabolismoRESUMEN
This study aimed to examine the impact of sodium tripolyphosphate (STPP) on the quality and digestive characteristics of PSE pork. The results showed a notable decrease in cooking loss of PSE pork from 29.11% to 25.67% with increasing STPP concentration (P < 0.05). Additionally, the gastric digestibility of PSE pork decreased significantly from 52.01% to 45.81% (P < 0.05). The particle size of digesta decreased significantly after gastrointestinal digestion (P < 0.05). These changes were primarily due to the enhanced cross-linking of proteins through ionic interactions, hydrogen bonds and hydrophobic interactions, and resulted in the embedding of hydrophobic groups and endogenous fluorophores. Furthermore, denser network was formed. These findings give a new insight into considering the impact of STPP on meat nutrition when used to enhance texture and water holding capacity.
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OBJECTIVE: To comprehensively review and critically assess the literature on microbiota differences between patients with interstitial cystitis (IC)/bladder pain syndrome (BPS) and normal controls and to provide clinical practice guidelines. MATERIALS AND METHODS: In this systematic review, we evaluated previous research on microbiota disparities between IC/BPS and normal controls, as well as distinctions among IC/BPS subgroups. A comprehensive literature search was conducted across PubMed/MEDLINE, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials. Relevant studies were shortlisted based on predetermined inclusion and exclusion criteria, followed by quality assessment. The primary focus was identifying specific taxonomic variations among these cohorts. RESULTS: A total of 12 studies met the selection criteria. Discrepancies were adjudicated by a third reviewer. The Newcastle-Ottawa Scale was used to assess study quality. Predominantly, the studies focused on disparities in urine microbiota between IC/BPS patients and normal controls, with one study examining gut microbiota differences between the groups, and two studies exploring vaginal microbiota distinctions. Unfortunately, analyses of discrepancies in other microbiota were limited. Our findings revealed evidence of distinct bacterial abundance variations, particularly involving Lactobacillus, alongside variations in specific metabolites among IC/BPS patients compared to controls. CONCLUSIONS: Currently, there is evidence suggesting significant variations in the diversity and species composition of the urinary microbiota between individuals diagnosed with IC/BPS and control groups. In the foreseeable future, urologists should consider urine microbiota dysbiosis as a potential aetiology for IC, with potential clinical implications for diagnosis and treatment.
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Cigarettes with pronounced astringency can diminish consumers' enjoyment. However, due to the complex composition of cigarettes, quantifying astringency intensity accurately has been challenging. To address this, research was conducted to develop a method for assessing astringency intensity in a simulated oral environment. The astringency intensity of four cigarette brands was determined using the standard sensory evaluation method. The mainstream smoke absorbing solution (MS) was prepared by simulating the cigarette smoking process, and its physicochemical properties (such as total phenol content and pH levels) were analyzed. The lubrication properties of the five solutions were tested using the MFT-5000 wear tester, and factors influencing cigarette astringency were examined. The findings showed that total phenol content and pH of MS were positively and negatively correlated with astringency intensity, respectively. Particularly, the lubrication properties of MS were significantly correlated with astringency intensity, and the correlation coefficient was affected by load and speed during testing. The study concluded that coefficient of friction was a more reliable measure for assessing the extent of astringency in cigarettes than the total phenol content and pH of MS, offering new insights into astringency evaluation and development of high-grade cigarettes.
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Gusto , Productos de Tabaco , Humanos , Productos de Tabaco/análisis , Adulto , Masculino , Concentración de Iones de Hidrógeno , Femenino , Adulto Joven , Lubrificación , Humo/análisis , Astringentes/análisis , Boca , Fenoles/análisis , Fumar , Persona de Mediana EdadRESUMEN
SCOPE: Epidemiological studies have linked excessive red and processed meat intake to gut disorders. Under laboratory conditions, high heme content is considered the primary health risk factor for red meat. However, heme in meat is present in myoglobin, which is an indigestible protein, suggesting the different functions between myoglobin and heme. This study aims to explore how dietary myoglobin and heme affect gut health and microbiota differently. METHODS AND RESULTS: Histological and biochemical assessments as well as 16S rRNA sequencing are performed. Moderate myoglobin intake (equivalent to the recommended intake of 150 g meat per day for human) has beneficial effects on the duodenal barrier. However, a too high myoglobin diet (equivalent to intake of 3000 g meat per day for human) triggers duodenum injury and alters the microbial community. The hemin diet destroys intestinal tissue and ileal microbiota more significantly. The in vitro experiments further confirm that free heme exhibits high toxicity to beneficial gut bacteria while myoglobin promotes the growth and metabolism of Limosilactobacillus reuteri. CONCLUSION: Moderate intake of myoglobin or hemin is beneficial to intestinal health and microbiota, but too high amounts lead to tissue inflammation and injury in the small intestine by reshaping ileal microbiota.
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Microbioma Gastrointestinal , Hemina , Inflamación , Mioglobina , Microbioma Gastrointestinal/efectos de los fármacos , Animales , Mioglobina/metabolismo , Hemina/farmacología , Masculino , Dieta/métodos , Intestino Delgado/efectos de los fármacos , Intestino Delgado/metabolismo , Limosilactobacillus reuteri , Duodeno/metabolismo , ARN Ribosómico 16S/genética , HemoRESUMEN
Myoglobin (Mb) responsible for meat color is easily oxidized resulting in meat discoloration. Here, betanin red (BR), as a natural pigment and antioxidant, was chosen for enhancing redness and inhibiting oxidation. Multiple spectroscopies, isothermal titration calorimetry and molecular docking demonstrated that BR changed the microenvironment of heme group and amino acid residues of Mb, inhibited the oxidation of oxymyoglobin. The main interaction force was hydrogen bond and one variable binding site provided a continuous protective barrier to realize antioxidation. The combination of antioxidation with the inherent red color of BR offered dual color protection effect on processed beef with the addition amount of 0.2 % BR. BR treatment enhanced the redness by 25.59 â¼ 53.24 % and the sensory acceptance by 4.89 â¼ 14.24 %, and decreased the lipid oxidation by 0.58 â¼ 15.92 %. This study paves a theoretical basis for the application of BR and its structural analogues in meat color protection and other quality improvement.
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Mioglobina , Carne Roja , Animales , Bovinos , Mioglobina/química , Antioxidantes/metabolismo , Simulación del Acoplamiento Molecular , Betacianinas , Carne/análisis , Oxidación-Reducción , Color , Carne Roja/análisisRESUMEN
Eating behavior is critical for maintaining energy homeostasis. Previous studies have found that plant-based meat analogues increased diet intake in mice compared with animal meat under a free feeding mode, however the reasons were unclear. To explore the underlying mechanisms of plant-based meat analogues increasing diet intake, mice were fed animal or plant-based pork and beef analogue diets, respectively. Biochemical and histological analyses were performed to evaluate appetite-regulating hormones and gastrointestinal motility function. Peptiomics and GC-IMS were applied to identify key substances. We found that the intake of plant-based meat analogues significantly enhanced the gastrointestinal motility function of mice. The long-term intake (68 days) of plant-based meat analogues significantly increased the muscle layer thickness of the duodenum and jejunum of mice; the activity of gastrointestinal cells of Cajal were also promoted by upregulating the expression of c-kit related signals as compared to animal meat; plant-based meat analogues intake markedly enhanced the signal intensity of the intestinal neurotransmitter 5-hydroxytryptamine (5-HT) by upregulating the expression of 5-HT synthase and receptors but downregulating its transporter and catabolic enzyme in the intestine. Moreover, plant-based meat analogues intake significantly increased levels of appetite-stimulating factors in the peripheral or hypothalamus but reduced levels of appetite-suppressing factors compared with animal meat. Specific volatile compounds were significantly associated with appetite regulating factors. Among them, 7 substances such as linalool have a potential promoting effect on food intake. Besides, different digestive peptides in gastrointestinal tract may affect eating behavior mainly through the neuroactive ligand-receptor interaction pathway, exerting hormone-like effects or influencing endocrine cell secretion. These findings preliminarily clarified the mechanism of plant-based meat analogues promoting diet intake and provided a theoretical basis for a reasonable diet.
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Apetito , Serotonina , Bovinos , Ratones , Animales , Apetito/fisiología , Serotonina/farmacología , Péptidos/farmacología , Motilidad Gastrointestinal , CarneRESUMEN
Insufficient protein and fat hydrolysis capacity of lactic acid bacteria (LAB) limit the flavor formation of fermented sausage. Bacillus is known for its substantial expression of proteases and lipases. However, its application in meat fermentation remains underexplored. In this study, a strain of probiotic Bacillus cereus (B. cereus DM423) was employed as a co-starter to improve the quality of Lactiplantibacillus plantarum (L. plantarum HH-LP56) fermented sausage. The addition of DM423 did not interfere with regular fermentation, but it significantly improved the flavor, as measured by electronic tongue and electronic nose. Further analyses using SDS-PAGE and thin-layer chromatography observed enhanced hydrolysis of protein and fat in sausages in which DM423 was involved in fermentation. GC-IMS identified DM423 mediated upregulation of various flavor compounds, including esters, ketones, furans, and branched-chain fatty acids. In addition, genomic de novo sequencing revealed that DM423 carried an abundance of genes associated with proteolysis, lipolysis, and the production of flavor substances, whereas HH-LP56 lacked these genes. Overall, this study finds that B. cereus DM423 can promote flavor formation in fermented sausages. It may illuminate a promising direction for the development of sausage co-starters from a wider microbial pool.
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Bacillus , Cactaceae , Productos de la Carne , Bacillus cereus/genética , Fermentación , ProteolisisRESUMEN
Rabies, a fatal viral zoonotic disease, has become a public health concern in Sarawak, Malaysia. Despite pre-exposure and post-exposure prophylaxis being available, there has been limited progress in developing treatments for rabies, emphasising the pressing need for productive solutions. We present a laboratory-confirmed human rabies case in which the patient survived without neurological sequelae after receiving intrathecal rabies immunoglobulin.
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Profilaxis Posexposición , Rabia , Humanos , Rabia/tratamiento farmacológico , Rabia/prevención & control , Inmunoglobulinas/uso terapéutico , Factores Inmunológicos , Progresión de la EnfermedadRESUMEN
Quantitative assessment of endogenously synthesized and released bilirubin from brain tissue remains a challenge. Here, we present a sensitive and reproducible experimental paradigm to quantify, in real time, unconjugated bilirubin (UCB) from isolated murine brain tissue during oxygen-glucose deprivation (OGD). We describe steps for perfusion, brain dissection, brain slice preparation and incubation, glucose depletion, and OGD processing. We then detail procedures for standard calibration plotting and sample UCB measurement. For complete details on the use and execution of this protocol, please refer to Liu et al.1.
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Glucosa , Oxígeno , Ratones , Animales , Bilirrubina , Encéfalo , CabezaRESUMEN
Ferroptosis, a form of cell death mediated by lipid peroxidation, is implicated in various pathological processes. Although monounsaturated fatty acids (MUFAs) can inhibit ferroptotic lipid peroxidation, the underlying structural mechanism of this antagonistic effect remains poorly understood. We hypothesized that MUFAs with different structures (including chain length, conformation, and double bond position) may affect their regulatory effect on ferroptosis. In this study, 11 MUFAs with varying structures were screened to identify those with an inhibitory effect on ferroptosis. Results from 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide assays indicated that only exogenous MUFAs with cis-conformation and centered double bond could inhibit ferroptosis. Meanwhile, it was found that suppressing the expression of SCD1 and SCD5 genes could sensitize cells to ferroptosis indicating the protective role of endogenous MUFA against ferroptosis. Additionally, western blot analysis revealed that cis-MUFAs with centered double bond downregulated the protein levels of transferrin receptor 1. Flow cytometry confirmed that these MUFAs led to decreases in intracellular iron, reactive oxygen species, and lipid peroxides. It was also found that SCD1 inhibitor could enhance ferroptosis inducer-mediated tumor suppression both in vivo and in vitro. Overall, these findings shed light on the particular structural features of MUFAs that contribute to their ferroptosis-resistant properties and suggest the potential therapeutic relevance of natural MUFAs in a range of ferroptosis-related diseases.
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Ácidos Grasos Monoinsaturados , Ferroptosis , Ácidos Grasos Monoinsaturados/farmacología , Regulación hacia Abajo , Muerte Celular , Receptores de Transferrina/metabolismo , Ácidos Grasos/farmacologíaRESUMEN
Ferroptosis due to polyunsaturated fatty acid (PUFA) peroxidation has been implicated in the pathogenesis of acute kidney injury (AKI), suggesting the risk of dietary intake of PUFA for people susceptible to AKI. Clinically, however, in addition to ferroptosis, other mechanisms also contribute to different types of AKI such as inflammation associated necroptosis and pyroptosis. Therefore, the role of PUFA, especially ω3 PUFA which is a common food supplement, in various AKIs deserves further evaluation. In this study, rhabdomyolysis- and folic acid-induced AKI (Rha-AKI and FA-AKI) were established in mice fed with different fatty acids Histology of kidney, blood urea nitrogen and creatinine, lipid peroxidation, and inflammatory factors were examined. Results showed that these two types of AKIs had diametrically different pathogenesis indicated by that ferrostatin-1 (Fer-1), a lipid antioxidant, can attenuate FA-AKI rather than Rha-AKI. Further, dietary DHA (provided by fish oil) reduced tubular injury and renal lesion by inhibiting peroxidation and inflammation in mice with Rha-AKI while increasing cell death, tissue damage, peroxidation and inflammation in mice with FA-AKI. In human renal tubular epithelial cell line HK-2, MTT assay and DHE staining showed that both myoglobin and ferroptosis inducers can cause cell death and oxidative stress. Ferroptosis inducer-induced cell death was promoted by DHA, while such result was not observed in myoglobin-induced cell death when adding DHA. This study illustrates that the mechanisms of AKI might be either ferroptosis dependent or -independent and the deterioration effect of dietary DHA depends on whether ferroptosis is involved.
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Lesión Renal Aguda , Ácidos Grasos Omega-3 , Humanos , Ratones , Animales , Ácidos Docosahexaenoicos/farmacología , Mioglobina/efectos adversos , Lesión Renal Aguda/inducido químicamente , Ácidos Grasos Omega-3/efectos adversos , Ácidos Grasos Insaturados/metabolismo , InflamaciónRESUMEN
Tuberculosis-associated hemophagocytic lymphohistiocytosis (TB-HLH) is a rare and life-threatening complication of tuberculosis infection. Early recognition and treatment of TB-HLH is crucial for improving outcomes. Treatment typically involves a combination of antituberculosis therapy and immunosuppressive therapy to control the immune system's overreaction. In this report, we present the case of a 53-year-old ambulance driver who was diagnosed with TB-HLH. His CT scan revealed splenic abscesses, hepatomegaly and bilateral lung consolidation. He subsequently developed multiorgan failure, including acute respiratory distress syndrome (ARDS), transaminitis and bone marrow dysfunction. The clinical course and simultaneous increase in serum ferritin raised the suspicion of HLH. His Hscore was 254, indicating a high probability of hemophagocytic syndrome. TB diagnosis was confirmed by positive endotracheal TB GeneXpert and bone marrow aspiration (BMA) which detected acid-fast bacilli organisms. The patient was promptly started on anti-TB, dexamethasone and IVIG. The patient responded well to treatment and made a full recovery without any lasting complications. This case highlights the importance of promptly recognising HLH and identifying the underlying cause. In critically ill patients, it is crucial not to delay HLH-specific treatment while working up for differential diagnosis.
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Linfohistiocitosis Hemofagocítica , Mycobacterium tuberculosis , Enfermedades del Bazo , Tuberculosis , Masculino , Humanos , Persona de Mediana Edad , Linfohistiocitosis Hemofagocítica/etiología , Linfohistiocitosis Hemofagocítica/complicaciones , Enfermedades del Bazo/complicaciones , Tuberculosis/complicaciones , Tuberculosis/diagnóstico , Tuberculosis/tratamiento farmacológico , Médula ÓseaRESUMEN
Optimizing cell substrates by surface modification of neural stem cells (NSCs), for efficient and oriented neurogenesis, represents a promising strategy for treating neurological diseases. However, developing substrates with the advanced surface functionality, conductivity, and biocompatibility required for practical application is still challenging. Here, Ti3 C2 Tx MXene is introduced as a coating nanomaterial for aligned poly(l-lactide) (PLLA) nanofibers (M-ANF) to enhance NSC neurogenesis and simultaneously tailor the cell growth direction. Ti3 C2 Tx MXene treatment provides a superior conductivity substrate with a surface rich in functional groups, hydrophilicity, and roughness, which can provide biochemical and physical cues to support NSC adhesion and proliferation. Moreover, Ti3 C2 Tx MXene coating significantly promotes NSC differentiation into both neurons and astrocytes. Interestingly, Ti3 C2 Tx MXene acts synergistically with the alignment of nanofibers to promote the growth of neurites, indicating enhanced maturation of these neurons. RNA sequencing analysis further reveals the molecular mechanism by which Ti3 C2 Tx MXene modulates the fate of NSCs. Notably, surface modification by Ti3 C2 Tx MXene mitigates the in vivo foreign body response to implanted PLLA nanofibers. This study confirms that Ti3 C2 Tx MXene provides multiple advantages for decorating the aligned PLLA nanofibers to cooperatively improve neural regeneration.
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Nanofibras , Células-Madre Neurales , Titanio/farmacología , NeuronasRESUMEN
BACKGROUND: The microsurgical treatment of paraclinoid aneurysms can be challenging due to the anatomical structures that surround them. OBJECTIVE: This study compared the clinical and angiographic outcomes of unruptured paraclinoid aneurysms treated with enterprise (EP) stents and low-profile visualized intraluminal support (LVIS) stents. METHODS: A retrospective analysis of the clinical and radiological data from 133 patients with 139 unruptured paraclinoid aneurysms, who received an EP or an LVIS stent between January 2017 and June 2021 at Taizhou People's Hospital, was performed. Immediate postoperative and follow-up angiographic results were analyzed retrospectively using the Raymond-Roy occlusion classification (RROC). Any complications following the procedure and the patients' clinical outcomes were noted. RESULTS: Enterprise stents were used for stent-assisted coiling in 64 patients with 68 aneurysms and LVIS stents were used in 69 patients with 71 aneurysms. Both groups exhibited an increase in the proportion of aneurysms meeting the criteria for RROC class I, but the LVIS group demonstrated a higher rate of aneurysms meeting the class I criteria compared with the EP group, both on immediate postoperative angiography (45.1% vs. 11.8%, p< 0.001) and on follow-up angiography (94.9% vs. 80.6%, p= 0.025). Procedure-related complications were experienced by 9.4% of patients in the EP group (one coil prolapse, two parent artery occlusions, and three thromboembolic events), and 8.7% of patients in the LVIS group (three stent-related thrombosis and three thromboembolic events). There were no statistically significant differences between the two groups in relation to perioperative complications (p= 0.746) or favorable clinical outcomes (p= 0.492). CONCLUSION: A greater proportion of aneurysms in the LVIS group met the criteria for RROC class I compared with the EP group. There is no significant difference in procedural complications or clinical outcomes between EP and LVIS stents. Although no aneurysm recurrence was observed during the short follow-up period, continued monitoring is required.
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Procedimientos Endovasculares , Aneurisma Intracraneal , Humanos , Estudios Retrospectivos , Aneurisma Intracraneal/cirugía , Resultado del Tratamiento , Angiografía Cerebral/métodos , Stents , Procedimientos Endovasculares/métodosRESUMEN
Inflammatory bowel disease (IBD) is a chronic recurrent intestinal disease. The incidence rate of IBD is increasing year by year, which seriously endangers human health worldwide. More and more studies have shown that medicinal plants or their main phytochemicals have great potential in the treatment of intestinal diseases. However, the disadvantages of low oral absorption rate, low biological distribution and low systemic bioavailability limit their clinical application to a certain extent. In recent years, the application of nanotechnology has made it possible to treat IBD. Nanoparticles (NPs) drug delivery system has attracted special attention in the treatment of IBD due to its small size, low immunogenicity, surface modification diversity, targeting and other advantages. Synthetic nanoparticles and extracellular vehicles (EVs) can deliver drug components to colon, and play a role in anti-inflammation, regulation of oxidative stress, improvement of intestinal flora, etc. In addition, some medicinal plants can secrete EVs by themselves, and carry biological molecules with therapeutic effects to act on the intestine. Some clinical trials to evaluate the safety, tolerance, toxicity and effectiveness of EVs-loaded drugs in IBD are also progressing steadily. This review introduces that synthetic nanoparticles and medicinal plants derived EVs can play an important role in the treatment of IBD by carrying the effective active phytochemicals of medicinal plants, and discuss the limitations of current research and future research needs, providing a scientific and reliable basis and perspective for further clinical application and promotion.
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Stroke prognosis is negatively associated with an elevation of serum bilirubin, but how bilirubin worsens outcomes remains mysterious. We report that post-, but not pre-, stroke bilirubin levels among inpatients scale with infarct volume. In mouse models, bilirubin increases neuronal excitability and ischemic infarct, whereas ischemic insults induce the release of endogenous bilirubin, all of which are attenuated by knockout of the TRPM2 channel or its antagonist A23. Independent of canonical TRPM2 intracellular agonists, bilirubin and its metabolic derivatives gate the channel opening, whereas A23 antagonizes it by binding to the same cavity. Knocking in a loss of binding point mutation for bilirubin, TRPM2-D1066A, effectively antagonizes ischemic neurotoxicity in mice. These findings suggest a vicious cycle of stroke injury in which initial ischemic insults trigger the release of endogenous bilirubin from injured cells, which potentially acts as a volume neurotransmitter to activate TRPM2 channels, aggravating Ca2+-dependent brain injury.
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Accidente Cerebrovascular , Canales Catiónicos TRPM , Animales , Ratones , Canales Catiónicos TRPM/genética , Canales Catiónicos TRPM/metabolismo , Bilirrubina/metabolismo , Ratones Noqueados , Encéfalo/metabolismo , Infarto , Calcio/metabolismoRESUMEN
SCOPE: Bile acids (BAs) have recently emerged as important regulators of many physiological and pathological processes. However, the change of colonic BAs induced by high-fat diet (HFD) and their effects on colonic barrier function remain to be further elucidated. METHODS AND RESULTS: C57BL/6 mice are divided into two groups and feed 12 weeks with diets differing for fat content. Higher levels of serum diamine oxidase (DAO) activity, endotoxin (ET), and d-lactate (d-LA) are observed in HFD-fed mice, indicating an increase in intestinal permeability. Real-time quantitative PCR and western blot analyses demonstrate that HFD downregulates tight junction proteins (TJs, including zonula-occludens 1 [ZO-1], Occludin, and Claudin1) and Muc2 expression in the colon. The colonic BA profiles are analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). HFD induces an increase in primary BAs but a decrease in secondary BAs. In human colonic cell line Caco-2, secondary BAs (deoxycholic acid [DCA], lithocholic acid [LCA], their 3-oxo- and iso- derivates) upregulate the expression of TJs and counteract DSS-induced increase in intestinal permeability at physiological concentrations. IsoDCA and isoLCA are the most effective ones. Moreover, supplementation of isoDCA or isoLCA also effectively prevents HFD-induced colonic barrier dysfunction in mice. CONCLUSION: These results demonstrate that secondary BAs (especially isomerized derivatives) may be important protectors for the colonic barrier function.