Causal Association Between Tea Consumption and Gout: A Mendelian Randomization Study.

OBJECTIVE: Evidence from prospective studies on the consumption of tea and risk of gout is conflicting and limited. We aimed to investigate the potential causal effects of tea intake on gout using Mendelian randomization (MR). METHODS: Genome-wide association studies in UK Biobank included 349 376 individuals and successfully discovered single-nucleotide polymorphisms linked to consumption of one cup of tea per day. Summary statistics from the Chronic Kidney Disease Genetics consortium included 13 179 cases and 750 634 controls for gout. Two-sample MR analyses were used to evaluate the relationship between tea consumption and gout risk. The inverse-variance weighted (IVW) method was used for primary analysis, and sensitivity analyses were also conducted to validate the potential causal effect. RESULTS: In this study, the genetically predicted increase in tea consumption per cup was associated with a lower risk of gout in the IVW method (OR: 0.90; 95% CI: 0.82-0.98). Similar results were found in weighted median methods (OR: 0.88; 95% CI: 0.78-1.00), while no significant associations were found in MR-Egger (OR: 0.89; 95% CI: 0.71-1.11), weighted mode (OR: 0.80; 95% CI: 0.65-0.99), and simple mode (OR: 1.01; 95% CI: 0.75-1.36). In addition, no evidence of pleiotropy was detected by MR-Egger regression (P=0.95) or MR-PRESSO analysis (P=0.07). CONCLUSION: This study provides evidence for the daily consumption of an extra cup of tea to reduce the risk of gout.

Melatonin Alleviates Acute Gouty Inflammation In Vivo and In Vitro.

The aim of this study was to identify the effects of melatonin on acute gouty inflammation and to investigate the underlying mechanisms. We found significantly lower serum melatonin levels in gout patients in the acute phase than in those in the remission phase or in normal individuals. The mRNA expression of melatonin receptor 2 (MT2) was also lower in gout patients than in normal individuals. To verify the in-vivo role of melatonin, a gouty arthritis model was established by intraarticular injection of monosodium urate (MSU, 1 mg) crystals into the paws of C57BL/6 mice. Joint inflammation in the mouse model was evaluated by measuring the thickness of the right paw/left paw, and the inflammation index was determined by examining infiltrating neutrophils with haematoxylin and eosin (H&E) staining. Melatonin was found to reduce both paw thickness and the inflammation index in the mouse model, and melatonin also reduced the mRNA levels of interleukin-1 beta (IL-1ß), IL-6 and NLR family pyrin domain containing 3 (NLRP3) inflammasome. To mimic gouty inflammation in vitro, mouse peritoneal macrophages were stimulated with lipopolysaccharides (LPS) plus MSU. Melatonin was revealed to reduce IL-1ß secretion by stimulated macrophages. The mRNA expression levels of IL-1ß and IL-6 were also inhibited by melatonin. Western blot analysis showed that the expression of NLRP3, caspase-1 and pro-IL-1ß was also inhibited by melatonin. In conclusion, our study demonstrated that melatonin alleviated gouty inflammation in vivo and in vitro, and the underlying mechanism may involve inhibiting the assembly of the NLRP3 inflammasome.

Adiponectin receptor agonist AdipoRon relieves endotoxin-induced acute hepatitis in mice.

BACKGROUND: Adiponectin is the most abundant adipokines that plays critical roles in the maintenance of energy homeostasis as well as inflammation regulation. The half-life of adiponectin is very short and the small-molecule adiponectin receptor agonist has been synthesized recently. In the present study, the potential roles of AdipoRon, an adiponectin receptor agonist, in a mouse model of lipopolysaccharide (LPS)/D-galactosamine (D-Gal)-induced acute hepatitis was explored. METHODS: BALB/c mice (n = 144, male) were divided into three sets. In set 1, 32 mice were randomized into four groups: the control group, the AdipoRon group, the LPS/D-Gal group, and the AdipoRon + LPS/D-Gal group. The mice in set 1 were sacrificed after LPS/D-Gal treatment, and the plasma samples were collected for detection of tumor necrosis factor-alpha (TNF-α). In set 2, the 32 mice were also divided into four groups similar to that of set 1. The mice were sacrificed 6 h after LPS/D-Gal injection and plasma samples and liver were collected. In set 3, 80 mice (divided into four groups, n = 20) were used for survival observation. The survival rate, plasma aminotransferases, histopathological damage were measured and compared between these four groups. RESULTS: AdipoRon suppressed the elevation of plasma aminotransferases (from 2106.3 ±â€Š781.9 to 286.8 ±â€Š133.1 U/L for alanine aminotransferase, P < 0.01; from 566.5 ±â€Š243.4 to 180.1 ±â€Š153.3 U/L for aspartate aminotransferase, P < 0.01), attenuated histopathological damage and improved the survival rate (from 10% to 60%) in mice with LPS/D-Gal-induced acute hepatitis. Additionally, AdipoRon down-regulated the production of TNF-α (from 328.6 ±â€Š121.2 to 213.4 ±â€Š52.2 pg/mL, P < 0.01), inhibited the activation of caspase-3 (from 2.04-fold to 1.34-fold of the control), caspase-8 (from 2.03-fold to 1.31-fold of the control), and caspase-9 (from 2.14-fold to 1.43-fold of the control), and decreased the level of cleaved caspase-3 (0.28-fold to that of the LPS/D-Gal group). The number of terminal deoxynucleotidyl transferase-mediated nucleotide nick-end labeling-positive apoptotic hepatocytes in LPS/D-Gal-exposed mice also reduced. CONCLUSIONS: These data indicated that LPS/D-Gal-induced acute hepatitis was effectively attenuated by the adiponectin receptor agonist AdipoRon, implying that AdipoRon might become a new reagent for treatment of acute hepatitis.

Comparative study on anorexigenic effect of glucagon-like peptide-1 receptor agonists in rats.

Glucagon-like peptide-1 (GLP-1) expression is shared by both intestinal cells and neurons of brainstem, which plays anorexigenic role on food intake. However, the exact source of physiological GLP-1 influencing food intake and pertinent mechanism of GLP-1 receptor agonists (GLP-1RA) remain unelucidated. In this study, the immediate early gene product c-Fos was chosen as the specific antigen for immunohistochemistry to show the certain areas of central nervous system (CNS) activation by the GLP-1RA. Thirty normal SD rats were randomly assigned to 3 groups, which were single intraperitoneally injected with Liraglutide (200 µg/kg), Exenatide (10 µg/kg) and saline, respectively. After injection, the amount of food intake and acute glycemic variation were assessed for comparison. The results showed that acute pharmacological dosage of GLP-1RA (Liraglutide or Exenatide) could significantly influence food intake. However, glycemic change indicated that the anorexic effect was dissociated with change in blood glucose in normal rats. Moreover, c-Fos was expressed significantly higher in major critical nuclei related to food intake in GLP-1RA groups when compared with the control group, and its expression was also found in spinal cord. The results suggested that acute administration of pharmacological doses of GLP-1 influences CNS via circulation and vagal pathways, especially on the arcuate nucleus (ARC) and the nucleus of solitary tract (NTS), and GLP-1 modulates autonomic nervous activities.

Serotonergically dependent antidepressant-like activity on behavior and stress axis responsivity of acacetin.

Acacetin, a natural flavonoid, possesses broad spectrum of pharmacological and biochemical activities, such as neuroprotection, antinociception and inhibition of monoamine oxidase. The current work aimed to investigate the antidepressant-like activity of acacetin in mice and explore the underlying mechanism(s). Chronic, but not acute, acacetin treatment (5, 15 or 45 mg/kg, p.o., once per day for three weeks) exerted in mice dose-dependently antidepressant-like activity, assessed by forced swim test (FST) and tail suspension test (TST). Although acacetin-treated mice showed normal circadian hypothalamo-pituitary-adrenal (HPA) axis activity, their endocrine responsivity to both acute restraint stress and intracerebroventricular injection of corticotropin-releasing factor (CRF) was buffered. The acacetin-triggered antidepressant-like activities are serotonergically dependent, since its impacts on behavior and stress responsivity were totally abolished by chemical depletion of brain serotonin by PCPA. Consistently, acacetin-treated mice showed escalated levels of brain monoamines especially serotonin and depressed activity of monoamine oxidase. Moreover, the acacetin-evoked anti-depression was preferentially counteracted by co-administration of 5-HT1A receptor antagonist WAY-100635, but potentiated by 5-HT1A receptor agonist 8-OH-DPAT and sub-effective dose of serotonergic antidepressant fluoxetine, suggesting a pivotal engagement of 5-HT1A related serotonergic system. In vitro, acacetin (1-100 nM) increased the Emax of 8-OH-DPAT. Collectively, these findings confirm that chronic acatetin administration to mice engenders antidepressant-like efficacy on both behavior and stress axis responsivity, with serotonergic system that preferentially couples with 5-HT1A receptors being critically involved.

Which is the best peri-operative anti-coagulative therapy of transverse sinus stenting for refractory idiopathic intracranial hypertension?

Treatment of refractory idiopathic intracranial hypertension (IIH) is a challenging problem. We reported a refractory IIH patient who manifested with typical intracranial hypertensive symptoms successfully treated with endovascular stent implantation. Pre-operative cerebrospinal fluid (CSF) opening pressure is 36 cmH2O. Cerebral angiography demonstrated a stenotic lesion located at the right transverse sinus (TS). The stenotic TS returned to its normal caliber and the pressure gradient deceased from 36 mmHg to 4 mmHg after the stent placement. The intracranial hypertensive symptoms resolved and one month later, the CSF opening pressure decreased to 14 cmH2O.