Protective Roles of N-acetyl Cysteine and/or Taurine against Sumatriptan-Induced Hepatotoxicity

Taurine Protects against the Fatty Liver Hemorrhagic Syndrome in Laying Hens through the Regulation of Mitochondrial Homeostasis

Metabolic-associated fatty liver disease (MAFLD) is a chronic liver disease caused by fat deposition in the liver of humans and mammals, while fatty liver hemorrhagic syndrome (FLHS) is a fatty liver disease in laying hens which can increase the mortality and cause severe economic losses to the laying industry. Increasing evidence has shown a close relationship between the occurrence of fatty liver disease and the disruption of mitochondrial homeostasis. Studies have proven that taurine can regulate hepatic fat metabolism, reduce hepatic fatty deposition, inhibit oxidative stress, and alleviate mitochondrial dysfunction. However, the mechanisms by which taurine regulates mitochondrial homeostasis in hepatocytes need to be further studied. In this study, we determined the effects and mechanisms of taurine on high-energy low-protein diet-induced FLHS in laying hens and in cultured hepatocytes in free fatty acid (FFA)-induced steatosis. The liver function, lipid metabolism, antioxidant capacity, mitochondrial function, mitochondrial dynamics, autophagy, and biosynthesis were detected. The results showed impaired liver structure and function, mitochondrial damage and dysfunction, lipid accumulation, and imbalance between mitochondrial fusion and fission, mitochondrial autophagy, and biosynthesis in both FLHS hens and steatosis hepatocytes. Taurine administration can significantly inhibit the occurrence of FLHS, protect mitochondria in hepatocytes from disease induced by lipid accumulation and FFA, up-regulate the expression levels of Mfn1, Mfn2, Opa1, LC3I, LC3II, PINK1, PGC-1α, Nrf1, Nrf2, and Tfam, and down-regulate the expression levels of Fis1, Drp1, and p62. In conclusion, taurine can protect laying hens from FLHS through the regulation of mitochondrial homeostasis, including the regulation of mitochondrial dynamics, autophagy, and biosynthesis.

Sumatriptan poisoning and its clinical presentation in humans: A case report

This case report displays some of the possible complications of sumatriptan poisoning, including nephritic syndrome.

Protective role of taurine against oxidative stress (Review)

Taurine is a fundamental mediator of homeostasis that exerts multiple roles to confer protection against oxidant stress. The development of hypertension, muscle/neuro‑​associated disorders, hepatic cirrhosis, cardiac dysfunction and ischemia/reperfusion are examples of some injuries that are linked with oxidative stress. The present review gives a comprehensive description of all the underlying mechanisms of taurine, with the aim to explain its anti‑oxidant actions. Taurine is regarded as a cytoprotective molecule due to its ability to sustain normal electron transport chain, maintain glutathione stores, upregulate anti‑oxidant responses, increase membrane stability, eliminate inflammation and prevent calcium accumulation. In parallel, the synergistic effect of taurine with other potential therapeutic modalities in multiple disorders are highlighted. Apart from the results derived from research findings, the current review bridges the gap between bench and bedside, providing mechanistic insights into the biological activity of taurine that supports its potential therapeutic efficacy in clinic. In the future, further clinical studies are required to support the ameliorative effect of taurine against oxidative stress.

Beyond Metabolism: Role of the Immune System in Hepatic Toxicity

The liver is primarily thought of as a metabolic organ; however, the liver is also an important mediator of immunological functions. Key perspectives on this emerging topic were presented in a symposium at the 2018 annual meeting of the American College of Toxicology entitled "Beyond metabolism: Role of the immune system in hepatic toxicity." Viral hepatitis is an important disease of the liver for which insufficient preventive vaccines exist. Host immune responses inadequately clear these viruses and often potentiate immunological inflammation that damages the liver. In addition, the liver is a key innate immune organ against bacterial infection. Hepatocytes and immune cells cooperatively control systemic and local bacterial infections. Conversely, bacterial infection can activate multiple types of immune cells and pathways to cause hepatocyte damage and liver injury. Finally, the immune system and specifically cytokines and drugs can interact in idiosyncratic drug-induced liver injury. This rare disease can result in a disease spectrum that ranges from mild to acute liver failure. The immune system plays a role in this disease spectrum.

The effects of acute sumatriptan treatment on renal ischemia/reperfusion injury in rat and the possible involvement of nitric oxide

Renal ischemia/reperfusion (I/R) injury is a common pathological condition. Studies reported renal toxicity following administration of triptans, which are commonly used for treating migraine headaches. To investigate the effects of sumatriptan and the molecular mechanisms involved in renal I/R injury in rats, ischemia was induced by bilateral clamping of renal pedicles followed by 24 h of reperfusion. Sumatriptan was administered in three different doses (5, 10, and 20 mg/kg) before I/R injury induction. Biochemical and histopathological changes were evaluated. The contribution of nitric oxide in modulating the effects of sumatriptan was determined by administrating aminoguanidine at 50 mg/kg 60 min before I/R injury. The tissue level of nitrite, superoxide dismutase (SOD), and malondialdehyde (MDA) were measured. Sumatriptan at 10 and 20 mg/kg increased the serum level of creatinine (Cr) and blood urea nitrogen (BUN) significantly. There was also a significant increase in nitrite level of animals that received 10 mg/kg sumatriptan. Co-administration of sumatriptan with aminoguanidine significantly decreased the BUN and Cr. Depletion of SOD level (P < 0.05) and elevation of serum levels of MDA (P < 0.001) indicated the involvement of oxidative stress in sumatriptan adverse effects. Overall, the administration of sumatriptan intensified renal I/R injury through activation of inducible nitric oxide synthase and oxidative responses in rats.

Compatible osmolytes modulate mitochondrial function in a marine osmoconformer Crassostrea gigas (Thunberg, 1793)

Salinity is an important environmental factor affecting physiology of marine organisms. Osmoconformers such as marine mollusks maintain metabolic function despite changes of the osmolarity and composition of the cytosol during salinity shifts. Currently, metabolic responses to the salinity-induced changes of the intracellular milieu are not well understood. We studied the effects of osmolarity (450 vs. 900 mOsm) and compatible osmolytes (70-590 mM of taurine or betaine) on isolated gill mitochondria of a marine osmoconformer, the Pacific oyster Crassostrea gigas. Physiological concentrations of taurine enhanced mitochondrial ATP synthesis and electron transport system (ETS) capacity, increased mitochondrial coupling and stimulated the forward flux through the Complex I. Notably, the stimulatory effects of taurine were more pronounced at 900 mOsm compared to 450 mOsm. In contrast, betaine proportionally increased the rates of the mitochondrial proton leak, oxidative phosphorylation and ETS flux (with no net effect on the mitochondrial coupling) and suppressed the activity of cytochrome c oxidase in oyster mitochondria. However, the effective concentration of betaine (590 mM) was higher than typically found in bivalves, and thus betaine is not likely to affect oyster mitochondria under the physiological conditions in vivo. Our findings indicate that taurine may support the mitochondrial bioenergetics during hyperosmotic stress in oysters. Compatibility of taurine with the metabolic functions and its beneficial effects on mitochondria may have contributed to its broad distribution as an osmolyte in marine osmoconformers and might explain the earlier reports of the positive effects of taurine supplementation on energy metabolism of other organisms, including mammals.

The preventive effects of taurine on neural tube defects through the Wnt/PCP-Jnk-dependent pathway

The aim of this study was to clarify the protective role of taurine in neuronal apoptosis and the role of the Wnt/PCP-Jnk pathway in mediating the preventive effects of taurine on neural tube defects (NTDs). HT-22 cells (a hippocampal neuron cell line) were divided into a control group, a glutamate-induced apoptosis group, and glutamate (4.0 mmol/L) plus low-dose taurine (L; 0.5 mmol/L) and high-dose taurine (H; 2.0 mmol/L) groups. The MTT assay was used to monitor cell proliferation and cell survival. Immunofluorescence and Western blot analyses were used to determine caspase 9 expression. Retinoic acid (RA) induced embryonic NTDs in Kunming mice, thus establishing an NTD model. Pregnant mice were divided into a control group, an RA (30 mg/kg body weight) group, and an RA (30 mg/kg body weight) plus taurine (free drinking of 2 g/L solution) group. Immunohistochemistry and Western blot analyses were used to detect the expression of Dvl, RhoA and phosphorylated (p)-Jnk/Jnk in the embryonic neural tubes. In HT-22 cells, the apoptosis rate was significantly higher and caspase 9 activation was also significantly increased in the glutamate-induced apoptosis group compared to the L and H taurine groups. In the NTD model, the expression levels of Dvl, RhoA, and p-Jnk were significantly higher in the RA group than in the control group, whereas they were significantly reduced in the RA + taurine group. This study suggests that taurine has positive effects on neuronal protection and NTD prevention. Moreover, the Wnt/PCP-Jnk-dependent pathway plays an important role in taurine-mediated prevention of NTDs.