Intestinal IL-33 promotes microbiota-derived trimethylamine N -oxide synthesis and drives metabolic dysfunction-associated steatotic liver disease progression by exerting dual regulation on HIF-1α.

BACKGROUND AND AIMS: Gut microbiota plays a prominent role in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD). IL-33 is highly expressed at mucosal barrier sites and regulates intestinal homeostasis. Herein, we aimed to investigate the role and mechanism of intestinal IL-33 in MASLD. APPROACH AND RESULTS: In both humans and mice with MASLD, hepatic expression of IL-33 and its receptor suppression of tumorigenicity 2 (ST2) showed no significant change compared to controls, while serum soluble ST2 levels in humans, as well as intestinal IL-33 and ST2 expression in mice were significantly increased in MASLD. Deletion of global or intestinal IL-33 in mice alleviated metabolic disorders, inflammation, and fibrosis associated with MASLD by reducing intestinal barrier permeability and rectifying gut microbiota dysbiosis. Transplantation of gut microbiota from IL-33 deficiency mice prevented MASLD progression in wild-type mice. Moreover, IL-33 deficiency resulted in a decrease in the abundance of trimethylamine N -oxide-producing bacteria. Inhibition of trimethylamine N -oxide synthesis by 3,3-dimethyl-1-butanol mitigated hepatic oxidative stress in mice with MASLD. Nuclear IL-33 bound to hypoxia-inducible factor-1α and suppressed its activation, directly damaging the integrity of the intestinal barrier. Extracellular IL-33 destroyed the balance of intestinal Th1/Th17 and facilitated Th1 differentiation through the ST2- Hif1a - Tbx21 axis. Knockout of ST2 resulted in a diminished MASLD phenotype resembling that observed in IL-33 deficiency mice. CONCLUSIONS: Intestinal IL-33 enhanced gut microbiota-derived trimethylamine N -oxide synthesis and aggravated MASLD progression through dual regulation on hypoxia-inducible factor-1α. Targeting IL-33 and its associated microbiota may provide a potential therapeutic strategy for managing MASLD.

Statins as a risk factor for diabetic retinopathy: a Mendelian randomization and cross-sectional observational study.

BACKGROUND: Diabetic retinopathy (DR) is the foremost cause of vision loss among the global working-age population, and statins are among the most frequently prescribed drugs for lipid management in patients with DR. The exact relationship between statins and DR has not been determined. This study sought to validate the causal association between statins usage and diabetic retinopathy. METHODS: The summary-data-based Mendelian randomization (SMR) method and inverse-variance-weighted Mendelian randomization (IVW-MR) were used to identify the causal relationship between statins and DR via the use of expression quantitative trait loci (eQTL) data for 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) (31,684 blood samples), low density lipoprotein cholesterol-related GWAS data (sample size: 440,546), and DR-related GWAS data (14,584 cases and 176,010 controls). Additionally, a cross-sectional observational study based on the data from the National Health and Nutrition Examination Survey (NHANES) was conducted to supplement the association between DR and statins (sample size: 106,911). The odds ratios (ORs) with corresponding 95% confidence intervals (CIs) was employed to evaluate the results. RESULTS: Based on the results of the MR analysis, HMGCR inhibitors were causally connected with a noticeably greater incidence of DR (IVW: OR = 0.54, 95% CI [0.42, 0.69], p = 0.000002; SMR: OR = 0.66, 95% CI [0.52, 0.84], p = 0.00073). Subgroup analysis revealed that the results were not affected by the severity of DR. The sensitivity analysis revealed the stability and reliability of the MR analysis results. The results from the cross-sectional study based on NHANES also support the association between not taking statins and a decreased risk of DR (OR = 0.54, 95% CI [0.37, 0.79], p = 0.001). CONCLUSIONS: This study revealed that a significant increase in DR risk was causally related to statins use, providing novel insights into the role of statins in DR. However, further investigations are needed to verify these findings.

Disease severity and antiviral response in patients with chronic hepatitis B with non-obese NAFLD.

BACKGROUND: The burden of nonalcoholic fatty liver disease (NAFLD) is growing in patients with chronic hepatitis B (CHB). NAFLD is typically associated with obesity, however, it is increasingly being identified in non-obese patients. This study aimed to investigate disease severity and antiviral response in non-obese patients with CHB with NAFLD (CHB + NAFLD). METHODS: A total of 809 patients with CHB + NAFLD were prospectively recruited and followed up for 3 years. NAFLD was diagnosed by transient elastography and defined as controlled attenuation parameter ≥248 dB/m, in the absence of excessive alcohol intake. Obesity status was defined by the Asian body mass index (BMI) cutoff of 25 kg/m2. Metabolic abnormality was defined by the presence of dyslipidemia, hypertension or diabetes. Fibrosis staging was defined according to the EASL-ALEH guidelines, with fibrosis progression defined as ≥1-stage increment. RESULTS: In the total cohort (median age 40 years, 59.0% antiviral-treated), 33.3% were non-obese. Non-obese patients were less metabolically abnormal than obese patients (60.2% vs 72.0%, P = 0.003). After 3-year follow up, the rate of fibrosis progression was comparable between non-obese and obese patients (17.5% vs 21.9% in the total cohort, P = 0.145; 15.7% vs 14.6% in antiviral-treated cohort with persistent viral suppression, P = 0.795). No significant differences in virological and biochemical responses were observed between non-obese and obese patients (P >0.05 for all). CONCLUSION: Approximately one third of CHB + NAFLD patients were non-obese. Non-obese patients, while less metabolically abnormal, had a similar risk for fibrosis progression as obese patients. Obesity status did not impact the efficiency of antiviral therapy.

C-C chemokine receptor 5 is essential for conventional NK cell trafficking and liver injury in a murine hepatitis virus-induced fulminant hepatic failure model.

BACKGROUND: Previous studies have demonstrated that natural killer (NK) cells migrated into the liver from peripheral organs and exerted cytotoxic effects on hepatocytes in virus-induced liver failure. AIM: This study aimed to investigate the potential therapeutic role of chemokine receptors in the migration of NK cells in a murine hepatitis  virus strain 3 (MHV-3)-induced fulminant hepatic failure (MHV-3-FHF) model and its mechanism. RESULTS: By gene array analysis, chemokine (C-C motif) receptor 5 (CCR5) was found to have remarkably elevated expression levels in hepatic NK cells after MHV-3 infection. The number of hepatic CCR5+ conventional NK (cNK) cells increased and peaked at 48 h after MHV-3 infection, while the number of hepatic resident NK (rNK) cells steadily declined. Moreover, the expression of CCR5-related chemokines, including macrophage inflammatory protein (MIP)-1α, MIP-1ß and regulated on activation, normal T-cell expressed and secreted (RANTES) was significantly upregulated in MHV-3-infected hepatocytes. In an in vitro Transwell migration assay, CCR5-blocked splenic cNK cells showed decreased migration towards MHV-3-infected hepatocytes, and inhibition of MIP-1ß or RANTES but not MIP-1α decreased cNK cell migration. Moreover, CCR5 knockout (KO) mice displayed reduced infiltration of hepatic cNK cells after MHV-3 infection, accompanied by attenuated liver injury and improved mouse survival time. Adoptive transfer of cNK cells from wild-type mice into CCR5 KO mice resulted in the abundant accumulation of hepatic cNK cells and aggravated liver injury. Moreover, pharmacological inhibition of CCR5 by maraviroc reduced cNK cell infiltration in the liver and liver injury in the MHV-3-FHF model. CONCLUSION: The CCR5-MIP-1ß/RANTES axis played a critical role in the recruitment of cNK cells to the liver during MHV-3-induced liver injury. Targeted inhibition of CCR5 provides a therapeutic approach to ameliorate liver damage during virus-induced acute liver injury.

Long-term SARS-CoV-2 neutralizing antibody level prediction using multimodal deep learning: A prospective cohort study on longitudinal data in Wuhan, China.

The ongoing epidemic of SARS-CoV-2 is taking a substantial financial and health toll on people worldwide. Assessing the level and duration of SARS-CoV-2 neutralizing antibody (Nab) would provide key information for government to make sound healthcare policies. Assessed at 3-, 6-, 12-, and 18-month postdischarge, we described the temporal change of IgG levels in 450 individuals with moderate to critical COVID-19 infection. Moreover, a data imputation framework combined with a novel deep learning model was implemented to predict the long-term Nab and IgG levels in these patients. Demographic characteristics, inspection reports, and CT scans during hospitalization were used in this model. Interpretability of the model was further validated with Shapely Additive exPlanation (SHAP) and Gradient-weighted Class Activation Mapping (GradCAM). IgG levels peaked at 3 months and remained stable in 12 months postdischarge, followed by a significant decline in 18 months postdischarge. However, the Nab levels declined from 6 months postdischarge. By training on the cohort of 450 patients, our long-term antibody prediction (LTAP) model could predict long-term IgG levels with relatively high area under the receiver operating characteristic curve (AUC), accuracy, precision, recall, and F1-score, which far exceeds the performance achievable by commonly used models. Several prognostic factors including FDP levels, the percentages of T cells, B cells and natural killer cells, older age, sex, underlying diseases, and so forth, served as important indicators for IgG prediction. Based on these top 15 prognostic factors identified in IgG prediction, a simplified LTAP model for Nab level prediction was established and achieved an AUC of 0.828, which was 8.9% higher than MLP and 6.6% higher than LSTM. The close correlation between IgG and Nab levels making it possible to predict long-term Nab levels based on the factors selected by our LTAP model. Furthermore, our model identified that coagulation disorders and excessive immune response, which indicate disease severity, are closely related to the production of IgG and Nab. This universal model can be used as routine discharge tests to identify virus-infected individuals at risk for recurrent infection and determine the optimal timing of vaccination for general populations.

Anti-VEGF combined with ocular corticosteroids therapy versus anti-VEGF monotherapy for diabetic macular edema focusing on drugs injection times and confounding factors of pseudophakic eyes: A systematic review and meta-analysis.

PURPOSE: To assess the effectiveness and safety of combining intravitreal endothelial growth factor inhibitor (anti-VEGF) and ocular corticosteroids for diabetic macular edema (DME). METHODS: Articles concentrating on the efficacy and safety of combining anti-VEGF and ocular corticosteroids therapy for DME versus anti-VEGF monotherapy was screened systematically. Meta-analysis was conducted on the basis of a protocol registered in the PROSPERO (CRD42023408338) and performed on the extracted continuous variables and dichotomous variables. The outcome was expressed as weighted mean difference (MD) and risk ratio (RR). RESULTS: Add up to 21 studies including 1468 eyes were enrolled in this study. The MD for best-corrected visual acuity (BCVA) improvement at 1/3/6/12-month between the combination therapy group and monotherapy group were 2.56 (95% CI [0.43, 4.70]), 2.46 (95% CI [-0.40, 5.32]), - 1.76 (95% CI [-3.18, -0.34]), - 1.94 (95% CI [-3.87, 0.00]), respectively. The MD for central retinal thickness (CMT) reduction at 1/3/6/12-month between two groups were - 66.27 (95% CI [-101.08, -31.47]), - 33.62 (95% CI [-57.55, -9.70]), - 4.54 (95% CI [-16.84, 7.76]), - 26.67 (95% CI [-41.52, -11.82]), respectively. Additionally, the combination group had higher relative risk of high intraocular pressure and cataract progression events. CONCLUSIONS: Anti-VEGF combined with ocular corticosteroids had a significant advantage over anti-VEGF monotherapy within 3 months of DME treatment, which reached the maximum with increasing anti-VEGF injection times to 3. However, with the prolongation of the treatment cycle, the effect of combined therapy after 6 months was no better than monotherapy, and the side effects of combined therapy were more severe.

Twelve-Month Systemic Consequences of Coronavirus Disease 2019 (COVID-19) in Patients Discharged From Hospital: A Prospective Cohort Study in Wuhan, China.

BACKGROUND: Follow-up study of coronavirus disease 2019 (COVID-19) survivors has rarely been reported. We aimed to investigate longitudinal changes in the characteristics of COVID-19 survivors after discharge. METHODS: A total of 594 COVID-19 survivors discharged from Tongji Hospital in Wuhan from February 10 to April 30, 2020 were included and followed up until May 17, 2021. Laboratory and radiological findings, pulmonary function tests, electrocardiogram, symptoms and signs were analyzed. RESULTS: 257 (51.2%) patients had at least one symptom at 3 months post-discharge, which decreased to 169 (40.0%) and 138 (28.4%) at 6-month and 12-month visit respectively. During follow-up period, insomnia, chest tightness, and fatigue were the most prevalent symptoms. Most laboratory parameters returned to normal, whereas increased incidence of abnormal liver and renal function and cardiovascular injury was evidenced after discharge. Fibrous stripes (213; 42.4%), pleural thickening and adhesions (188; 37.5%) and enlarged lymph nodes (120; 23.9%) were the most common radiographical findings at 3 months post-discharge. The abnormalities of pulmonary function included obstructive, restrictive, and mixed, which were 5.5%, 4.0%, 0.9% at 6 months post, and 1.9%, 4.7%, 0.2% at 12 months. Electrocardiogram abnormalities occurred in 256 (51.0%) patients at 3 months post-discharge, including arrhythmia, ST-T change and conduction block, which increased to 258 (61.1%) cases at 6-month visit and were maintained at high frequency (242;49.8%) at 12-month visit. CONCLUSIONS: Physiological, laboratory, radiological, or electrocardiogram abnormalities, particularly those related to renal, cardiovascular, and liver functions are common in patients who recovered from coronavirus disease 2019 (COVID-19) up to 12 months post-discharge.

End-of-treatment HBcrAg and HBsAb levels identify durable functional cure after Peg-IFN-based therapy in patients with CHB.

BACKGROUND & AIMS: Functional cure can be sustained in a proportion of patients with chronic hepatitis B (CHB) who lose hepatitis B surface antigen (HBsAg) after pegylated interferon alpha (Peg-IFN-ɑ)-based treatment. In this study, we aimed to identify biomarkers associated with a durable functional cure and to dissect potential immunological mechanisms. METHODS: Of 257 nucleos(t)ide analogue-suppressed patients with CHB in the ANCHOR study, 80 patients randomly assigned to 96-week Peg-IFN-α-based therapy with 24-week off-treatment follow-up were included in this parallel study. Virologic and immunological biomarkers were examined dynamically. A response was defined as HBsAg loss or hepatitis B surface antibody (HBsAb) appearance at the end of treatment (EOT). Sustained response (SR) or durable functional cure was defined as sustained HBsAg loss with or without the appearance of HBsAb at the end of follow-up (EOF). RESULTS: Thirty-six (45.0%) out of 80 patients achieved a response at EOT; 58.3% (21/36) of responders maintained SR at EOF. Quantitative hepatitis B core-related antigen (qHBcrAg) and HBsAb at EOT were associated with SR, with AUROCs of 0.697 (0.512-0.882, p = 0.047) and 0.744 (0.573-0.915, p = 0.013), respectively. A combination of HBcrAg <4 log10U/ml and HBsAb >2 log10IU/L at EOT had a positive predictive value of 100% for SR with an AUROC of 0.822 (0.684-0.961, p = 0.001). These patients showed maintained proportions of HBV envelope-specific CD8+T and B cells, a markedly increased proportion of T follicular helper cells after Peg-IFN-ɑ discontinuation, and significantly higher proportions of HBV polymerase-specific CD8+T and CD86+CD19+B cells at EOF. CONCLUSIONS: Lower HBcrAg and higher HBsAb levels at EOT were associated with sustained cellular and humoral immune responses. They can be used to identify patients likely to achieve durable functional cure post Peg-IFN-based therapy. GOV IDENTIFIER: NCT02327416 LAY SUMMARY: Functional cure can be sustained in a proportion of patients with chronic hepatitis B after pegylated interferon alpha-based treatment. However, predicting who will achieve durable functional cure remains challenging. Herein, we show that low levels of hepatitis B core-related antigen and higher levels of hepatitis B surface antibodies at the end of treatment are linked to immunological responses and are associated with durable functional cure.

Hepatic exosomes with declined MiR-27b-3p trigger RIG-I/TBK1 signal pathway in macrophages.

BACKGROUND AND AIMS: Evidence suggests that interferon alpha (IFNα) plays an essential role in decreasing the HBsAg quantification and elevating the rate of clinical cure in chronic hepatitis B (CHB). However, the mechanisms underlying the effects of the exosomes on the expression of host genes in IFNα treatment remain unclear. METHODS: CHB patients with IFNα treatment were divided into responders and non-responders according to the degree of HBsAg decline. Through microRNA sequencing and a series of molecular biology methods, the key microRNAs in serum exosomes associated with clinical antiviral response of Peg-IFNα treatment in nucleotide analogue-treated CHB patients were investigated. The roles of exosomal miRNAs on the IFNα signal pathway were explored in macrophages. RESULTS: MicroRNA sequencing and RT-qPCR assays confirmed six distinctly declined miRNAs in serum exosomes of responders at week 12 compared with levels at baseline. Exosomes with declined miR27b-3p in the serum of Peg-IFNα-treated responders activated phosphorylation of interferon regulatory factor 3/7 (IRF3/7) in IFNα synthesis pathway in macrophages. However, miR27b-3p overexpression in HepAD38 cells suppressed IFNα synthesis in macrophages, resulting in insufficient ability to eliminate HBV, whereas the inhibitory effect could be blocked by inhibitors of exosomes release. Luciferase assay showed miR-27b-3p directly suppressed retinoic acid-inducible gene I (RIG-I) and TANK-binding kinase 1 (TBK1) expressions, and these effects could be abrogated in mutation experiments. CONCLUSIONS: In IFNα treatment, exosomes with declined miR-27b-3p triggered activation of RIG-I/TBK1 signalling in macrophages against HBV. Serum exosomal miR-27-3p might represent a potential biomarker for patients with CHB.

Pegylated Interferon-ɑ (IFN-ɑ) Enhances the Inhibitory Effect of Natural Killer Cells on Regulatory T Cells via IFN-γ in Chronic Hepatitis B.

The immunomodulatory role of natural killer (NK) cells has been recognized recently, but its effects on CD4+CD25+ regulatory T cells (Tregs) during chronic hepatitis B (CHB) infection and treatment remain unclear. A total of 116 nucleos(t)ide analogue (NA)-treated CHB patients were included. An inverse correlation between the peripheral frequencies of NK cells and Tregs was found in NA suppressed patients following pegylated interferon-ɑ (PegIFN-ɑ)-based treatment. Furthermore, NK cells suppressed the proliferation and differentiation of Tregs through secreting IFN-γ as was evidenced in the circulation of NA-treated CHB patients as well as in liver of HBV-carrier mouse model. Additionally, the inhibition could be enhanced by PegIFN-ɑ treatment, which was correlated to more vigorous HBV-specific T-cell responses and marked reduction in HBsAg. Our study reveals a novel immunomodulatory mechanism of NK cells and provides a theoretical basis for PegIFN-ɑ as an immunotherapy agent in treating patients with CHB.

Interferon-Induced Macrophage-Derived Exosomes Mediate Antiviral Activity Against Hepatitis B Virus Through miR-574-5p.

BACKGROUND: Interferon alfa (IFN-α) has been proved effective in treating chronic hepatitis B (CHB), owing to its ability to suppress hepatitis B surface antigen and hepatitis B virus (HBV) covalently closed circular DNA. However, the underlying mechanisms are unclear. METHODS: We investigated the antiviral activities of exosomes from responders and nonresponders to pegylated IFN-α (PegIFN-α) as well as the supernatants of IFN-α-treated macrophages derived from THP-1 (the human leukemia monocyte cell line). Then the expression profiles of exosomal microRNAs (miRNAs) were analyzed using miRNA sequencing. The luciferase reporter assay was used to locate the binding position of HBV genomic sequence targeted by the identified miRNA. RESULTS: Exosomes from PegIFN-α-treated patients, particularly responders, as well as the supernatants of IFN-α-treated macrophages exhibited anti-HBV activities, as manifested by the suppression of hepatitis B surface antigen, hepatitis B e antigen, HBV DNA, and covalently closed circular DNA levels in HBV-related cell lines. PegIFN-α treatment up-regulated exosomal hsa-miR-193a-5p, hsa-miR-25-5p, and hsa-miR-574-5p, which could partially inhibit HBV replication and transcription, and hsa-miR-574-5p reduced pregenomic RNA and polymerase messenger RNA levels by binding to the 2750-2757 position of the HBV genomic sequence. CONCLUSIONS: Exosomes can transfer IFN-α-related miRNAs from macrophages to HBV-infected hepatocytes, and they exhibit antiviral activities against HBV replication and expression.

Longitudinal changes of inflammatory parameters and their correlation with disease severity and outcomes in patients with COVID-19 from Wuhan, China.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a newly emerging infectious disease and rapidly escalating epidemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The pathogenesis of COVID-19 remains to be elucidated. We aimed to clarify correlation of systemic inflammation with disease severity and outcomes in COVID-19 patients. METHODS: In this retrospective study, baseline characteristics, laboratory findings, and treatments were compared among 317 laboratory-confirmed COVID-19 patients with moderate, severe, or critically ill form of the disease. Moreover, the longitudinal changes of serum cytokines, lactate dehydrogenase (LDH), high-sensitivity C-reactive protein (hsCRP), and hsCRP to lymphocyte count ratio (hsCRP/L) as well as their associations with disease severity and outcomes were investigated in 68 COVID-19 patients. RESULTS: Within 24 h of admission, the critically ill patients showed higher concentrations of inflammatory markers including serum soluble interleukin (IL)-2 receptor, IL-6, IL-8, IL-10, tumor necrosis factor alpha (TNF-α), ferritin, procalcitonin, LDH, hsCRP, and hsCRP/L than patients with severe or moderate disease. The severe cases displayed the similar response patterns when compared with moderate cases. The longitudinal assays showed the levels of pro-inflammatory cytokines, LDH, hsCRP, and hsCRP/L gradually declined within 10 days post admission in moderate, severe cases or those who survived. However, there was no significant reduction in cytokines, LDH, hsCRP, and hsCRP/L levels in critically ill or deceased patients throughout the course of illness. Compared with female patients, male cases showed higher serum concentrations of soluble IL-2R, IL-6, ferritin, procalcitonin, LDH, and hsCRP. Multivariate logistic regression analysis revealed that IL-6 > 50 pg/mL and LDH > 400 U/L on admission were independently associated with disease severity in patients with COVID-19. CONCLUSION: Exuberant inflammatory responses within 24 h of admission in patients with COVID-19 may correlate with disease severity. SARS-CoV-2 infection appears to elicit a sex-based differential immune response. IL-6 and LDH were independent predictive parameters for assessing the severity of COVID-19. An early decline of these inflammation markers may be associated with better outcomes.

Protection of retinal function and morphology in MNU-induced retinitis pigmentosa rats by ALDH2: an in-vivo study.

BACKGROUND: Retinitis pigmentosa (RP) is a kind of inherited retinal degenerative diseases characterized by the progressive loss of photoreceptors. RP has been a conundrum without satisfactory countermeasures in clinic until now. Acetaldehyde dehydrogenase 2 (ALDH2), a major enzyme involved in aldehyde detoxification, has been demonstrated to be beneficial for a growing number of human diseases, such as cardiovascular dysfunction, diabetes mellitus and neurodegeneration. However, its protective effect against RP remains unknown. Our study explored the impact of ALDH2 on retinal function and structure in N-methyl-N-nitrosourea (MNU)-induced RP rats. METHODS: Rats were gavaged with 5 mg/kg Alda-1, an ALDH2 agonist, 5 days before and 3 days after MNU administration. Assessments of retinal function and morphology as well as measurement of specific proteins expression level were conducted. RESULTS: Electroretinogram recordings showed that Alda-1 administration alleviated the decrease in amplitude caused by MNU, rendering protection of retinal function. Mitigation of photoreceptor degeneration in MNU-treated retinas was observed by optical coherence tomography and retinal histological examination. In addition, Western blotting results revealed that ALDH2 protein expression level was upregulatedwith increased expression of SIRT1 protein after the Alda-1 intervention. Besides, endoplasmic reticulum stress (ERS) was reduced according to the significant downregulation of GRP78 protein, while apoptosis was ameliorated as shown by the decreased expression of PARP1 protein. CONCLUSIONS: Together, our data demonstrated that ALDH2 could provide preservation of retinal function and morphology against MNU-induced RP, with the underlying mechanism at least partly related to the modulation of SIRT1, ERS and apoptosis.

Protective effects of hydrogen gas in a rat model of branch retinal vein occlusion via decreasing VEGF-α expression.

BACKGROUND: Oxidative stress (OS) is an essential factor in the pathogenesis of branch retinal vein occlusion (BRVO). Studies have demonstrated the role of hydrogen gas in the regulation of OS. This study was designed to evaluate the efficacy of hydrogen gas on the BRVO rat model. METHODS: Twenty-four BRVO rats were randomly divided into two groups: the hydrogen gas (H) group (42% H2, 21% O2, 37% N2) and the model (M) group (21% O2, 79% N2). Rats in the H group inhaled hydrogen gas for 8 h every day up to 30 d post-occlusion. Twelve age-matched healthy rats served as the control (C) group. Retinal function and morphology were detected at 1, 7, 14 and 30 d post-occlusion. Furthermore, the expression of vascular endothelial growth factor (VEGF-α) was detected by immunofluorescent staining. RESULTS: Full-field electroretinography (ffERG) revealed that the amplitude of the b-wave (dark-adaptation 3.0 response), the amplitude of the OPs2 wave and the light-adapted flicker response in the H group were all higher than those in the M group at 7 d post-occlusion (all p < 0.05). The reopen time of occlusive retinal vessels in the H group was 2.235 ± 1.128 d, which was shorter than that in the M group (4.234 ± 2.236 d, p < 0.05). The rats in the H group had a thinner IPL + GCL + NFL and an increased total retina compared with those in the M group at 3 d post-occlusion (p < 0.05), while the rats in the H group had a thicker INL, IPL + GCL + NFL and total retina compared with those at 7, 14 and 30 d post-occlusion (p < 0.05). Moreover, the flow velocity of ear vein blood was increased in the H group compared with that in the M group (p < 0.05). The expression of VEGF-α in the H group was dramatically decreased compared with that in the M group at 1, 7 and 14 d post-occlusion (p < 0.05), while the expression kept in similar level at 30 d post-occlusion (p > 0.05). CONCLUSIONS: Our findings demonstrate that inhalation of hydrogen gas could alleviate retinal oedema, shorten reopen time and improve retinal function, and the potential mechanism might be related to a decrease in VEGF-α expression.

A Natural Occurring Mouse Model with Adgrv1 Mutation of Usher Syndrome 2C and Characterization of its Recombinant Inbred Strains.

BACKGROUND/AIMS: Our laboratory discovered a Kunming mouse with enormous electroretinogram (ERG) defects. Its auditory brainstem response (ABR) threshold was significantly elevated and closely resembled the features of Usher syndrome (USH). This study sought to cross these USH-like mice (named KMush/ush mice) with CBA/CaJ mice to establish recombinant inbred strains and identify their phenotypes and genotypes. METHODS: KMush/ush mice were crossed with CBA/CaJ mice to establish inbred strains by sibling mating. ERG, ABR, ocular fundus morphology, histological examinations of the retina and inner ear, quantitative real-time polymerase chain reaction, western blotting, and exon sequencing were performed to assess the phenotypes and genotypes of the offspring strains. RESULTS: The F1 hybrids from crossing KMush/ush and CBA/CaJ mice had normal ERG and ABR responses. The F2 offspring from intercrossing the F1 mice showed a segregation of the retinitis pigmentosa (RP) and hearing loss phenotypes. The CBA-1ush/ush mice had an RP phenotype that was characterized by a vanished ERG waveform and loss of the outer nuclear layer. Their Pde6b gene had a nonsense mutation that resulted in the failure of protein production in western blotting. However, the ABR threshold of this strain of mice was normal. The CBA-2ush/ush mice had normal retinal function and architecture. Their ABR threshold was increased, with a dramatic degeneration of the stereocilia bundles in the outer hair cells of the inner ear. Whole exome sequencing and exon sequencing revealed a deletion of one base pair in exon 31 of the Adgrv1 gene, which would result in the premature termination of protein encoding. The level of Adgrv1 mRNA was reduced in the CBA-2ush/ush mice. The CBA-3ush/ush mice had phenotypes of RP, elevated ABR threshold, and degeneration of the stereocilia bundles in the outer hair cells. They were closely associated with the nonsense mutations of Pde6b and Adgrv1, respectively. CONCLUSION: We isolated a mouse strain with hearing loss from inbred mice with retinal degeneration and established it as a recombinant inbred strain with a spontaneous mutation in Adgrv1, the human Usher syndrome 2C gene. The retinal degeneration was cause by a mutation in Pde6b, while the hearing loss was caused by a mutation in Adgrv1.

Soluble Fgl2 restricts autoimmune hepatitis progression via suppressing Tc17 and conventional CD8+ T cell function.

BACKGROUND: Autoimmune hepatitis (AIH) is an inflammatory disease caused by an aberrant immune response to hepatic self-antigens in which regulatory T cells (Tregs) are critical for maintaining immunosupression. The soluble form of fibrinogen-like protein 2 (sFGL2), a novel effector molecule of Treg, is rarely investigated in AIH. In the present study, we dissected the role of sFGL2 in autoimmune hepatitis and its potential mechanism underlying AIH progression. METHODS: Plasma and intrahepatic sFGL2 levels, as well as Treg cells, were measured in both AIH patients and experimental autoimmune hepatitis (EAH) mice. Th1, Th2, Th17 and Treg-related cytokines were measured in the liver of EAH mice. Treg expression of sFgl2 and its effect on CD8+ T cell activity in EAH were assessed. The clinical relevance of sFGL2 in AIH-associated inflammation and fibrosis was evaluated. RESULTS: Th17 responses is predominant in robust AIH patients and EAH mice. In AIH patients and EAH mice, the frequency of plasma Tregs was reduced, whereas intrahepatic Tregs were increased significantly. The plasma sFGL2 level was significantly higher at active phases compared to those during remission and was correlated with AIH progression. Enhanced sFGL2 expression was found in Tregs and inhibited conventional CD8+ T cells and Tc17 cell in EAH mice ex vivo. CONCLUSIONS: The Th17 response dominates autoimmune hepatitis progression. The increase in intrahepatic and plasma sFGL2 by Tregs may restrict AIH progression by inhibiting conventional CD8+ T cells and Tc17 cell function. The high correlation between sFGL2 and disease severity may predict AIH outcome.

Intrahepatic recruitment of cytotoxic NK cells contributes to autoimmune hepatitis progression.

Autoimmune hepatitis (AIH) is a chronic autoimmune disease with the primary focus on autoreactive Th1-mediated response and cytotoxic T cells reaction. The contribution of natural killer cells (NK cells) to AIH remains poorly understood. In this project, we revealed that the frequency of peripheral NK cells, more accurately CD56dimNK subset, was reduced in AIH patients. The reduction of CD56dimNK was negatively correlated with disease progression. In experimental autoimmune hepatitis (EAH), hepatic accumulation of NK cells is observed along with a decrease of NK cells in the periphery. In addition, infiltrated NK cells are almost conventional CXCR3- NK cells, the counterpart of CD56dimNK cells in the human. Furthermore, conventional CXCR3-NK cells of infiltration and liver resident NK cells are activated progressively at active phase. Therefore, recruitment of cytotoxic NK cells into the liver, but not liver resident NK cells expansion, may partly account for AIH progression.

Effects of Post-Treatment Hydrogen Gas Inhalation on Uveitis Induced by Endotoxin in Rats.

BACKGROUND Molecular hydrogen (H2) has been widely reported to have benefiicial effects in diverse animal models and human disease through reduction of oxidative stress and inflammation. The aim of this study was to investigate whether hydrogen gas could ameliorate endotoxin-induced uveitis (EIU) in rats. MATERIAL AND METHODS Male Sprague-Dawley rats were divided into a normal group, a model group, a nitrogen-oxygen (N-O) group, and a hydrogen-oxygen (H-O) group. EIU was induced in rats of the latter 3 groups by injection of lipopolysaccharide (LPS). After that, rats in the N-O group inhaled a gas mixture of 67% N2 and 33% O2, while those in the H-O group inhaled a gas mixture of 67% H2 and 33% O2. All rats were graded according to the signs of uveitis after electroretinography (ERG) examination. Protein concentration in the aqueous humor (AqH) was measured. Furthermore, hematoxylin-eosin staining and immunostaining of anti-ionized calcium-binding adapter molecule 1 (Iba1) in the iris and ciliary body (ICB) were carried out. RESULTS No statistically significant differences existed in the graded score of uveitis and the b-wave peak time in the Dark-adapted 3.0 ERG among the model, N-O, and H-O groups (P>0.05), while rats of the H-O group showed a lower concentration of AqH protein than that of the model or N-O group (P<0.05). The number of the infiltrating cells in the ICB of rats from the H-O group was not significantly different from that of the model or N-O group (P>0.05), while the activation of microglia cells in the H-O group was somewhat reduced (P<0.05). CONCLUSIONS Post-treatment hydrogen gas inhalation did not ameliorate the clinical signs, or reduce the infiltrating cells of EIU. However, it inhibited the elevation of protein in the AqH and reduced the microglia activation.

The NLRP3 Inflammasome and IL-1ß Accelerate Immunologically Mediated Pathology in Experimental Viral Fulminant Hepatitis.

Viral fulminant hepatitis (FH) is a severe disease with high mortality resulting from excessive inflammation in the infected liver. Clinical interventions have been inefficient due to the lack of knowledge for inflammatory pathogenesis in the virus-infected liver. We show that wild-type mice infected with murine hepatitis virus strain-3 (MHV-3), a model for viral FH, manifest with severe disease and high mortality in association with a significant elevation in IL-1ß expression in the serum and liver. Whereas, the viral infection in IL-1ß receptor-I deficient (IL-1R1-/-) or IL-1R antagonist (IL-1Ra) treated mice, show reductions in virus replication, disease progress and mortality. IL-1R1 deficiency appears to debilitate the virus-induced fibrinogen-like protein-2 (FGL2) production in macrophages and CD45+Gr-1high neutrophil infiltration in the liver. The quick release of reactive oxygen species (ROS) by the infected macrophages suggests a plausible viral initiation of NLRP3 inflammasome activation. Further experiments show that mice deficient of p47phox, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit that controls acute ROS production, present with reductions in NLRP3 inflammasome activation and subsequent IL-1ß secretion during viral infection, which appears to be responsible for acquiring resilience to viral FH. Moreover, viral infected animals in deficiencies of NLRP3 and Caspase-1, two essential components of the inflammasome complex, also have reduced IL-1ß induction along with ameliorated hepatitis. Our results demonstrate that the ROS/NLRP3/IL-1ß axis institutes an essential signaling pathway, which is over activated and directly causes the severe liver disease during viral infection, which sheds light on development of efficient treatments for human viral FH and other severe inflammatory diseases.