Protective effects of Tinospora cordifolia miers extract against hepatic and neurobehavioral deficits in thioacetamide-induced hepatic encephalopathy in rats via modulating hyperammonemia and glial cell activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Tinospora cordifolia (TC) a potential medicinal herb, has been ethnobotanically used as an eco-friendly supplement to manage various diseases, including cerebral fever. Earlier studies have shown that TC exhibits diverse beneficial effects, including hepatoprotective and neuroprotective effects. However, the effects of TC remain unexplored in animal models of encephalopathy including hepatic encephalopathy (HE). AIM OF THE STUDY: To evaluate the effects of TC stem extract against thioacetamide (TAA)-induced behavioural and molecular alterations in HE rats. METHODS AND MATERIALS: The extract was preliminarily screened through phytochemical and HR-LC/MS analysis. Animals were pre-treated with TC extract at doses 30 and 100 mg/kg, orally. Following 7 days of TC pre-treatment, HE was induced by administering TAA (300 mg/kg, i. p. thrice). Behavioural assessments were performed after 56 h of TAA first dose. The animals were then sacrificed to assess biochemical parameters in serum, liver and brain. Liver tissue was used for immunoblotting and histological studies to evaluate inflammatory and fibrotic signalling. Moreover, brain tissue was used to evaluate brain edema, activation of glial cells (GFAP, IBA-1) and NF-κB/NLRP3 downstream signalling via immunoblotting and immunohistochemical analysis in cortex and hippocampus. RESULTS: The pre-treatment with TC extract effective mitigated TAA-induced behavioural alterations, lowered serum LFT (AST, ALT, ALP, bilirubin) and oxidative stress markers in liver and brain. TC treatment significantly modulated hyperammonemia, cerebral edema and preserved the integrity of BBB proteins in HE animals. TC treatment attenuated TAA-induced histological changes, tissue inflammation (pNF-κB (p65), TNF-α, NLRP3) and fibrosis (collagen, α-SMA) in liver. In addition, immunoblotting analysis revealed TC pre-treatment inhibited fibrotic proteins such as vimentin, TGF-ß1 and pSmad2/3 in the liver. Our study further showed that TC treatment downregulated the expression of MAPK/NF-κB inflammatory signalling, as well as GFAP and IBA-1 (glial cell markers) in cortex and hippocampus of TAA-intoxicated rats. Additionally, TC-treated animals exhibited reduced expression of caspase3/9 and BAX induced by TAA. CONCLUSION: This study revealed promising insights on the protective effects of TC against HE. The findings clearly demonstrated that the significant inhibition of MAPK/NF-κB signalling and glial cell activation could be responsible for the observed beneficial effects of TC in TAA-induced HE rats.

L-carnitine supplementation for muscle weakness and fatigue in children with neurofibromatosis type 1: A Phase 2a clinical trial.

Reduced muscle tone, muscle weakness, and physical fatigue can impact considerably on quality of life for children with neurofibromatosis type 1 (NF1). Human muscle biopsies and mouse models of NF1 deficiency in muscle show intramyocellular lipid accumulation, and preclinical data have indicated that L-carnitine supplementation can ameliorate this phenotype. The aim of this study is to examine whether daily L-carnitine supplementation is safe and feasible, and will improve muscle strength and reduce fatigue in children with NF1. A 12-week Phase 2a trial was conducted using 1000 mg daily oral levocarnitine tartrate supplementation. Recruited children were between 8 and 12 years old with a clinical diagnosis of NF1, history of muscle weakness and fatigue, and naïve to L-carnitine. Primary outcomes were safety (self-reporting, biochemical testing) and compliance. Secondary outcomes included plasma acylcarnitine profiles, functional measures (muscle strength, long jump, handwriting speed, 6-minute-walk test [6MWT]), and parent-reported questionnaires (PedsQL™, CBCL/6-18). Six children completed the trial with no self-reported adverse events. Biochemical tests for kidney and liver function were normal, and the average compliance was 95%. Plasma acylcarnitine levels were low, but within a range not clinically linked to carnitine deficiency. For strength measures, there was a mean 53% increase in dorsiflexion strength (95% confidence interval [CI] 8.89-60.75; p = 0.02) and mean 66% increase in plantarflexion strength (95% CI 12.99-134.1; p = 0.03). In terms of muscle performance, there was a mean 10% increase in long jump distance (95% CI 2.97-16.03; p = 0.01) and 6MWT distance (95% CI 5.88-75.45; p = 0.03). Comparison with the 1000 Norms Project data showed a significant improvement in Z-score for all of these measures. Parent reports showed no negative impact on quality of life, and the perceived benefits led to the majority of individuals remaining on L-carnitine after the study. Twelve weeks of L-carnitine supplementation is safe and feasible in children with NF1, and a Phase 3 trial should confirm the efficacy of treatment.

Gene delivery corrects N-acetylglutamate synthase deficiency and enables insights in the physiological impact of L-arginine activation of N-acetylglutamate synthase.

The urea cycle protects the central nervous system from ammonia toxicity by converting ammonia to urea. N-acetylglutamate synthase (NAGS) catalyzes formation of N-acetylglutamate, an essential allosteric activator of carbamylphosphate synthetase 1. Enzymatic activity of mammalian NAGS doubles in the presence of L-arginine, but the physiological significance of NAGS activation by L-arginine has been unknown. The NAGS knockout (Nags-/-) mouse is an animal model of inducible hyperammonemia, which develops hyperammonemia without N-carbamylglutamate and L-citrulline supplementation (NCG + Cit). We used adeno associated virus (AAV) based gene transfer to correct NAGS deficiency in the Nags-/- mice, established the dose of the vector needed to rescue Nags-/- mice from hyperammonemia and measured expression levels of Nags mRNA and NAGS protein in the livers of rescued animals. This methodology was used to investigate the effect of L-arginine on ureagenesis in vivo by treating Nags-/- mice with AAV vectors encoding either wild-type or E354A mutant mouse NAGS (mNAGS), which is not activated by L-arginine. The Nags-/- mice expressing E354A mNAGS were viable but had elevated plasma ammonia concentration despite similar levels of the E354A and wild-type mNAGS proteins. The corresponding mutation in human NAGS (NP_694551.1:p.E360D) that abolishes binding and activation by L-arginine was identified in a patient with NAGS deficiency. Our results show that NAGS deficiency can be rescued by gene therapy, and suggest that L-arginine binding to the NAGS enzyme is essential for normal ureagenesis.

Inducible Slc7a7 Knockout Mouse Model Recapitulates Lysinuric Protein Intolerance Disease.

Lysinuric protein intolerance (LPI) is a rare autosomal disease caused by defective cationic amino acid (CAA) transport due to mutations in SLC7A7, which encodes for the y+LAT1 transporter. LPI patients suffer from a wide variety of symptoms, which range from failure to thrive, hyperammonemia, and nephropathy to pulmonar alveolar proteinosis (PAP), a potentially life-threatening complication. Hyperammonemia is currently prevented by citrulline supplementation. However, the full impact of this treatment is not completely understood. In contrast, there is no defined therapy for the multiple reported complications of LPI, including PAP, for which bronchoalveolar lavages do not prevent progression of the disease. The lack of a viable LPI model prompted us to generate a tamoxifen-inducible Slc7a7 knockout mouse (Slc7a7-/-). The Slc7a7-/- model resembles the human LPI phenotype, including malabsorption and impaired reabsorption of CAA, hypoargininemia and hyperammonemia. Interestingly, the Slc7a7-/- mice also develops PAP and neurological impairment. We observed that citrulline treatment improves the metabolic derangement and survival. On the basis of our findings, the Slc7a7-/- model emerges as a promising tool to further study the complexity of LPI, including its immune-like complications, and to design evidence-based therapies to halt its progression.

Chrysin, a flavonoid attenuates histological changes of hyperammonemic rats: A dose dependent study.

Chrysin (5,7-dihydroxyflavone) is a major component of some traditional medicinal herbs present in honey, propolis and many plant extracts. The study was aimed to illuminate the effect of chrysin in the pathogenesis of ammonium chloride (NH4Cl) induced hyperammonemic rat model in a dose dependent manner. Rats were injected with NH4Cl (100mg/kg b.w.) by intraperitonially (i.p) thrice a week for 8 consecutive weeks for the induction of experimental hyperammonemia. Hyperammonemic rats were treated with chrysin by orally at a dose of 25, 50 & 100mg/kg b.w. respectively. Protective effect of chrysin against hyperammonemia was evaluated by performing biochemical estimations and morphopathological investigations of hematoxylin and eosin stained sections of liver, brain and kidney tissues. Supplementation of chrysin reinstated the levels of blood ammonia, plasma urea, uric acid, total bilirubin, creatinine, brain glutamate, glutamine, nitric oxide (NO) and the activities of Na(+)/K(+)-ATPase, and liver marker enzymes. On the other hand increased level of plasma urea was observed in chrysin treated rats as compared with hyperammonemic rats. Chrysin administration caused distortion of hepatic, brain and kidney architecture as shown by histological examination. Chrysin at a dose (100mg/kg b.w.) showed an utmost decline in the level of all biochemical estimations. Both biochemical and morphological studies clearly revealed that chrysin protects against cell injury induced by ammonia intoxication in a dose-response manner with respect to endogenous antioxidants and hypoammonemic effects.

DNA microarray analysis identified molecular pathways mediating the effects of supplementation of branched-chain amino acids on CCl4-induced cirrhosis in rats.

SCOPE: This study addresses the effects of branched-chain amino acids (BCAA) on global gene expression in liver and skeletal muscle and the molecular mechanisms underlying the improvement in liver cirrhosis using DNA microarray analysis combined with RNase protection assay. METHODS AND RESULTS: Male Wistar rats administered carbon tetrachloride (CCl(4) ) repeatedly for 19 weeks as a decompensated cirrhosis model were thereafter given BCAA-enriched diet (AL) or normal diet (LC) for 5 weeks. The control-diet rats without CCl(4) administration were used as a normal control group. Gene expression in AL was reversed by twofold greater than in LC in the microarray were selected to elucidate the improvements in nutritional and metabolic disorders. Downregulation of fatty acid translocase (FAT)/Cd36, glutamine synthetase, and pyruvate dehydrogenase kinase isoenzyme 4 is believed to promote lower uptake of fatty acids, lower ammonia incorporation, and higher uptake of glucose, and thus to provide an energy source without using BCAA. Ultimately, the catabolism of BCAA and skeletal muscle protein would be slowed, maintaining BCAA concentrations in blood. CONCLUSION: We established, for the first time, the regulatory gene pathways of processes involved in hepatic fibrosis and energy metabolism (hypoalbuminemia, hyperammonemia, and carbohydrate catabolism, and their relationships) under BCAA supplementation.

Acute hepatic encephalopathy: diffusion-weighted and fluid-attenuated inversion recovery findings, and correlation with plasma ammonia level and clinical outcome.

BACKGROUND AND PURPOSE: In acute hepatic encephalopathy, MR imaging abnormalities have been described in the PVWM, thalami, and corticospinal tracts. We sought to determine characteristic regions of involvement on FLAIR and DWI, to evaluate their reversibility, and to correlate MR imaging extent with clinical severity. MATERIALS AND METHODS: Twenty patients who presented clinically with acute hepatic encephalopathy and MR imaging <21 days after symptom onset were reviewed retrospectively. Two neuroradiologists recorded involved regions on FLAIR and DWI in each, measured ADC values in affected regions and NAWM, and scored the MR imaging severity/extent. The initial severity (West Haven grade), follow-up clinical severity (degree of improvement), and maximal PAL within ±8 days of MR imaging were recorded and correlated with the MR imaging severity. RESULTS: On FLAIR and DWI respectively, there were abnormalities in the thalami (85%, 70%), PLIC (75%, 80%), PVWM (80%, 85%), and DBS (70%, 35%) and diffuse cortical involvement (30%, 25%). There were relatively strong significant (P < .005) correlations of FLAIR (r = 0.680, P = .001) and DWI severity (r = 0.690, P = .001) with PAL, and of PAL with the clinical outcome (r = 0.691, P = .001). Both FLAIR (r = 0.592, P = .006) and DWI (r = 0.487, P = .029) severity correlated moderately with the clinical outcome but were not significant at the P < .005 level after Bonferroni correction. CONCLUSIONS: Patients with acute hepatic encephalopathy may exhibit characteristic regions of involvement on FLAIR with DWI findings that can be reversible. The MR imaging extent on FLAIR and DWI strongly correlates with the maximal PAL, and PAL correlates well with the clinical outcome. Diffuse cortical involvement has a higher potential for neurologic sequelae but can be reversible.