Mechanisms of gastrointestinal toxicity in neuromyelitis optica spectrum disorder patients treated with mycophenolate mofetil: insights from a mouse model and human study.

Mycophenolate mofetil (MMF) is commonly utilized for the treatment of neuromyelitis optica spectrum disorders (NMOSD). However, a subset of patients experience significant gastrointestinal (GI) adverse effects following MMF administration. The present study aims to elucidate the underlying mechanisms of MMF-induced GI toxicity in NMOSD. Utilizing a vancomycin-treated mouse model, we compiled a comprehensive data set to investigate the microbiome and metabolome in the GI tract to elucidate the mechanisms of MMF GI toxicity. Furthermore, we enrolled 17 female NMOSD patients receiving MMF, who were stratified into non-diarrhea NMOSD and diarrhea NMOSD (DNM) groups, in addition to 12 healthy controls. The gut microbiota of stool samples was analyzed using 16S rRNA gene sequencing. Vancomycin administration prevented weight loss and tissue injury caused by MMF, affecting colon metabolomes and microbiomes. Bacterial ß-glucuronidase from Bacteroidetes and Firmicutes was linked to intestinal tissue damage. The DNM group showed higher alpha diversity and increased levels of Firmicutes and Proteobacteria. The ß-glucuronidase produced by Firmicutes may be important in causing gastrointestinal side effects from MMF in NMOSD treatment, providing useful information for future research on MMF. IMPORTANCE: Neuromyelitis optica spectrum disorder (NMOSD) patients frequently endure severe consequences like paralysis and blindness. Mycophenolate mofetil (MMF) effectively addresses these issues, but its usage is hindered by gastrointestinal (GI) complications. Through uncovering the intricate interplay among MMF, gut microbiota, and metabolic pathways, this study identifies specific gut bacteria responsible for metabolizing MMF into a potentially harmful form, thus contributing to GI side effects. These findings not only deepen our comprehension of MMF toxicity but also propose potential strategies, such as inhibiting these bacteria, to mitigate these adverse effects. This insight holds broader implications for minimizing complications in NMOSD patients undergoing MMF therapy.

Early autoimmunity and outcome in virus encephalitis: a retrospective study based on tissue-based assay.

To explore the autoimmune response and outcome in the central nervous system (CNS) at the onset of viral infection and correlation between autoantibodies and viruses. METHODS: A retrospective observational study was conducted in 121 patients (2016-2021) with a CNS viral infection confirmed via cerebrospinal fluid (CSF) next-generation sequencing (cohort A). Their clinical information was analysed and CSF samples were screened for autoantibodies against monkey cerebellum by tissue-based assay. In situ hybridisation was used to detect Epstein-Barr virus (EBV) in brain tissue of 8 patients with glial fibrillar acidic protein (GFAP)-IgG and nasopharyngeal carcinoma tissue of 2 patients with GFAP-IgG as control (cohort B). RESULTS: Among cohort A (male:female=79:42; median age: 42 (14-78) years old), 61 (50.4%) participants had detectable autoantibodies in CSF. Compared with other viruses, EBV increased the odds of having GFAP-IgG (OR 18.22, 95% CI 6.54 to 50.77, p<0.001). In cohort B, EBV was found in the brain tissue from two of eight (25.0%) patients with GFAP-IgG. Autoantibody-positive patients had a higher CSF protein level (median: 1126.00 (281.00-5352.00) vs 700.00 (76.70-2899.00), p<0.001), lower CSF chloride level (mean: 119.80±6.24 vs 122.84±5.26, p=0.005), lower ratios of CSF-glucose/serum-glucose (median: 0.50[0.13-0.94] vs 0.60[0.26-1.23], p=0.003), more meningitis (26/61 (42.6%) vs 12/60 (20.0%), p=0.007) and higher follow-up modified Rankin Scale scores (1 (0-6) vs 0 (0-3), p=0.037) compared with antibody-negative patients. A Kaplan-Meier analysis revealed that autoantibody-positive patients experienced significantly worse outcomes (p=0.031). CONCLUSIONS: Autoimmune responses are found at the onset of viral encephalitis. EBV in the CNS increases the risk for autoimmunity to GFAP.

The complement and immunoglobulin levels in NMO patients.

Since the discovery of aquaporin-4 (AQP4) antibody a decade ago, neuromyelitis optica (NMO) has been distinguished from multiple sclerosis (MS). MS mainly features T lymphocyte-oriented autoimmune responses while NMO is more precisely influenced by humoral immunity, among which the complement activation has always been reckoned as an important mechanism. The AQP4 antibody, namely NMO-IgG, adds to new evidence of how complement affects the severity of NMO. We compared the levels of complement (C3, C4, CH50) and immunoglobulins (IgG, IgM, IgA) between NMO patients and controls. Groups with AQP4 antibody positive and negative NMO patients were also compared with controls, respectively, aiming to elaborate on the relationship between complement activation and immunoglobulins. We also compared these indexes together with expanded disability status scale (EDSS) between two different groups in NMO patients and endeavored to figure out their correlations with each other. Complement and immunoglobulins were compared between NMO patients in acute phase and non-acute phase of the disease to find out the level fluctuation of CH50 and other indexes during different stages of NMO. We analyzed NMO patients (n = 88) and controls (n = 44) for IgG, IgM, IgA, other indexes like CH50, C3, C4 have also been explored between the two groups. Furthermore, we investigated whether these antibodies could mediate complement-dependent cytotoxicity. Thus, the NMO patients were split into two groups with or without AQP4 antibody to find out the status of NMO-IgG in the development and severity of the disease. EDSS was used as criteria for the evaluating the seriousness of NMO. Comparison between NMO patients in acute stage and non-acute stage of the disease was also made for a better understanding of the disease. Compared with controls, NMO patients had much higher IgG (13.984 ± 5.981 mg/ml, 11.430 ± 3.254 mg/ml, P < 0.01) but lower CH50 (respectively, 43.55 ± 12.172 U/L, 50.66 ± 12.523 U/L, P < 0.01). While IgG increased in Anti-AQP4 antibody-positive NMO patients, CH50 dropped in this group when compared with AQP4-negative patients. When compared with controls, both of the NMO groups had enhanced IgG and decreased CH50 though only AQP4-positive NMO patients showed significance (IgG 15.004 ± 6.613 mg/ml, 11.430 ± 3.254 mg/ml, P < 0.01) (CH50, respectively, 41.12 ± 12.581U/L, 50.66 ± 12.523 U/L, P < 0.01). C4 was also decreased though without evident significance (0.215 ± 0.118 mg/ml, 0.260 ± 0.133 mg/ml, P = 0.069). Those NMO patients in acute phase (with the course of newly attack of less than 1 month) had increased immunoglobulin (IgG 14.991 ± 6.639 mg/ml, 12.460 ± 4.490 mg/ml) but decreased complement (CH50 42.755 ± 12.403 U/L, 44.743 ± 11.890 U/L) than those who passed the acute phase. There was correlation between IgG and CH50 (R = -0.402, P < 0.01) in NMO patients. Relationship was also found between IgG and EDSS (R = 0.609, P < 0.001), CH50 and EDSS (R = -0.333, P < 0.01). These results indicate that NMO patients had enhanced immunoglobulin in acute phase but decreased complement. The complement was correlated with immunoglobulin. Among the two NMO groups, the complement system was only activated in NMO-IgG positive patients, which might indicate a potential different pathogenetic mechanism in NMO-IgG negative patients. Also, patients' disability of the former group was more serious than their counterparts. Those patients in acute phase obviously had increased immunoglobulin but decreased complement. Thus, we have come to the conclusion that in AQP4-positive NMO patients, immunoglobulin activates complement system, which influences the functions of NMO patients.

Combined therapy with methylprednisolone and ulinastatin in experimental autoimmune encephalomyelitis.

BACKGROUND: Our previous study had demonstrated that ulinastatin (UTI) had a neuroprotective effect in experimental autoimmune encephalomyelitis (EAE). Methylprednisolone has been recommended to be a standard drug in multiple sclerosis (MS) therapies. The present study was to investigate the protective effects of UTI combined methylprednisolone in EAE. METHODS: Mice were divided into a UTI treatment group, a methylprednisolone treatment group, a combined treatment group with UTI and methylprednisolone, a normal saline treatment group, and a normal control group. EAE mice were induced in groups receiving different combined treatments, or respective monotherapies. Demyelination was evaluated by Solochrome cyanin staining. 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP)/ myelin basic protein (MBP)/ the precursor form of nerve growth factor (proNGF)/p75/ inducible nitric oxide synthase (iNOS) proteins in cerebral cortex of EAE were detected by Western blotting. RESULTS: The combined treatment group had a lower clinical score (0.61 ± 0.06) and demyelinating score (1.33 ± 0.33) than the groups with normal saline (clinical score: 1.39 ± 0.08, P < 0.001; demyelinating score: 2.75 ± 0.49, P < 0.05) or monotheraphies. Compared with the saline treated EAE group, UTI combined methylprednisolone significantly increased expressions of CNP (1.14 ± 0.06 vs. 0.65 ± 0.04, P < 0.001), MBP (1.28 ± 0.14 vs. 0.44 ± 0.17, P < 0.001), and decreased expressions of proNGF (1.08 ± 0.10 vs. 2.32 ± 0.12, P < 0.001), p75 (1.13 ± 0.13 vs. 2.33 ± 0.17, P < 0.001), and iNOS (1.05 ± 0.31 vs. 2.17 ± 0.13, P < 0.001) proteins in EAE. Furthermore, UTI combined methylprednisolone could significantly upregulate MBP (1.28 ± 0.14 vs. 1.01 ± 0.15, P < 0.05) expression and downregulate iNOS (1.05 ± 0.31 vs. 1.35 ± 0.14, P < 0.05) expression compared to methylprednisolone treatment EAE group. And proNGF expression was significantly lower in combined treatment (1.08 ± 0.10) than that in UTI (1.51 ± 0.24, P < 0.05) or methylprednisolone (1.31 ± 0.04, P < 0.05) treatment group. CONCLUSION: Combination treatment of UTI with methylprednisolone was shown to protect EAE, suggesting that combination therapy is a potential novel treatment in MS.

Effects of Naoxintong on atherosclerosis and inducible nitric oxide synthase expression in atherosclerotic rabbit.

BACKGROUND: High levels of nitric oxide (NO) produced by inducible NO synthase (iNOS) have been associated with atherosclerosis processes. Naoxintong is a traditional Chinese medicine for treatment of cerebrovascular and cardiovascular disease. The aim of the present study was to detect and quantify changes of iNOS mRNA and NO levels in the vessel wall after the administration of Naoxintong in an atherosclerotic rabbit model. METHODS: Forty New Zealand white rabbits were randomly divided into five groups (n = 8). Rabbits were fed a standard diet (group A), an atherogenic diet consisting of 79% standard feed + 1% cholesterol + 5% lard + 15% egg yolk powder (group B), an atherogenic diet with Naoxintong 0.25 mg×kg(-1)×d(-1) (group C), an atherogenic diet with Naoxintong 0.5 mg×kg(-1)×d(-1) (group D), or atherogenic diet with Naoxintong 1.0 mg×kg(-1)×d(-1) (group E) for 12 weeks. RESULTS: Supplemented administration of Naoxintong led to a down-regulation of cholesterol (CHOL) (P < 0.001) and low-density lipoprotein (LDL) (P < 0.001). The trend became more notable as the dose of Naoxintong increased; group C vs. group B (CHOL, P = 0.568; LDL-cholesterol (LDL-C), P = 0.119), group D vs. group B (CHOL, P = 0.264; LDL-C, P = 0.027), group E vs. group B (CHOL, P = 0.028; LDL-C, P = 0.002). Atherosclerotic lesions in aorta were reduced in Naoxintong groups (groups C, D, E) compared to group B. Group B had higher iNOS mRNA (P = 0.001) and NO level (P < 0.001) than group A. Compared with the atherogenic diet fed-rabbits, Naoxintong supplements decreased the expression of iNOS mRNA (P < 0.001) and the NO level (P < 0.001) in the vessel wall. Groups given a higher Naoxintong dose exhibited greater benefits. iNOS mRNA and NO levels seemed to be reduced in group C, although the difference did not quite reach statistical significance (iNOS mRNA, P = 0.130; NO, P = 0.038). iNOS mRNA and NO levels significantly decreased in group D (iNOS mRNA, P = 0.019; NO, P = 0.018) and group E (iNOS mRNA, P = 0.004; NO, P < 0.001). CONCLUSION: Naoxintong has beneficial effects on atherosclerosis treatment by reducing expression of iNOS mRNA and the NO level in the vessel wall.