Role of leukotriene B4 (LTB4)-LTB4 receptor 1 signaling in post-incisional nociceptive sensitization and local inflammation in mice.

Leukotriene B4 (LTB4) is a potent lipid mediator involved in the recruitment and activation of neutrophils, which is an important feature of tissue injury and inflammation. The biological effects of LTB4 are primarily mediated through the high-affinity LTB4 receptor, BLT1. Postoperative incisional pain is characterized by persistent acute pain at the site of tissue injury and is associated with local inflammation. Here, we compared the role of LTB4-BLT1 signaling in postoperative incisional pain between BLT1-knockout (BLT1KO) and wild-type (BLT1WT) mice. A planter incision model was developed, and mechanical pain hypersensitivity was determined using the von Frey test before and after incision. Local infiltration of neutrophils and inflammatory monocytes was quantified by flow cytometry. Inflammatory cytokine levels in the incised tissue were also determined. Mechanical pain hypersensitivity was significantly reduced in BLT1KO mice compared to BLT1WT mice at 2, 3, and 4 days after incision. LTB4 levels in the tissue at the incision site peaked 3 hours after the incision. Infiltrated neutrophils peaked 1 day after the incision in both BLT1KO and BLT1WT mice. The accumulation of inflammatory monocytes increased 1-3 days after the incision and was significantly more reduced in BLT1KO mice than in BLT1WT mice. In BLT1KO mice, Interleukin-1ß and Tumor Necrosis Factor-α levels 1 day after the incision were significantly lower than those of BLT1WT mice. Our data suggest that LTB4 is produced and activates its receptor BLT1 in the very early phase of tissue injury, and that LTB4-BLT1 signaling exacerbates pain responses by promoting local infiltration of inflammatory monocytes and cytokine production. Thus, LTB4-BLT1 signaling is a potential target for therapeutic intervention of acute and persistent pain induced by tissue injury.

Lysophosphatidic acid receptor1/3 antagonist inhibits the activation of satellite glial cells and reduces acute nociceptive responses.

Lysophosphatidic acid (LPA) exerts various biological activities through six characterized G protein-coupled receptors (LPA1-6 ). While LPA-LPA1  signaling contributes toward the demyelination and retraction of C-fiber and induces neuropathic pain, the effects of LPA-LPA1  signaling on acute nociceptive pain is uncertain. This study investigated the role of LPA-LPA1  signaling in acute nociceptive pain using the formalin test. The pharmacological inhibition of the LPA-LPA1 axis significantly attenuated formalin-induced nociceptive behavior. The LPA1  mRNA was expressed in satellite glial cells (SGCs) in dorsal root ganglion (DRG) and was particularly abundant in SGCs surrounding large DRG neurons, which express neurofilament 200. Treatment with LPA1/3 receptor (LPA1/3 ) antagonist inhibited the upregulation of glial markers and inflammatory cytokines in DRG following formalin injection. The LPA1/3 antagonist also attenuated phosphorylation of extracellular signal-regulated kinase, especially in SGCs and cyclic AMP response element-binding protein in the dorsal horn following formalin injection. LPA amounts after formalin injection to the footpad were quantified by liquid chromatography/tandem mass spectrometry, and LPA levels were found to be increased in the innervated DRGs. Our results indicate that LPA produced in the innervated DRGs promotes the activation of SGCs through LPA1 , increases the sensitivity of primary neurons, and modulates pain behavior. These results facilitate our understanding of the pathology of acute nociceptive pain and demonstrate the possibility of the LPA1 on SGCs as a novel target for acute pain control.

Efficacy and safety of short-term therapy with indigo naturalis for ulcerative colitis: An investigator-initiated multicenter double-blind clinical trial.

INTRODUCTION: Indigo naturalis (IN) is a blue pigment extracted from Assam indigo and other plants and has been confirmed to be highly effective for ulcerative colitis (UC) treatment in several clinical studies. OBJECTIVE: We conducted a multicenter double-blind study to confirm the efficacy and safety of short-term IN administration. METHODS: A multicenter, randomized controlled trial was conducted between December 2015 and October 2018 in our facilities. Forty-six patients with mild to moderate active UC (Lichtiger index: 5-10) were randomly assigned to the IN group or the placebo group and received 5 capsules (500 mg) twice a day for 2 weeks. We investigated the efficacy according to blood tests and the Lichtiger index before and after administration, and we also examined adverse events. RESULTS: The analysis included 42 patients (20 males, 22 females) with an average age of 45 years. Nineteen patients were assigned to the placebo group, and 23 were assigned to the IN group. After treatment administration, in the placebo group, no change in the Lichtiger index was observed (7.47 to 6.95, p = 0.359), and hemoglobin was significantly reduced (12.7 to 12.4, p = 0.031), while in the IN group, the Lichtiger index (9.04 to 4.48, p = 0.001) and albumin (4.0 to 4.12, p = 0.022) improved significantly. Mild headaches were observed in 5 patients and 1 patient in the IN and placebo groups, respectively. CONCLUSIONS: Short-term administration of IN is highly effective without serious adverse events such as pulmonary hypertension or intussusception and may prevent the occurrence of serious adverse events.

Preliminary investigation of aluminium fluoride complexes in aqueous solutions with capillary electrophoresis coupled with electrospray ionization mass spectrometry and with inductively coupled plasma mass spectrometry.

RATIONALE: It is crucial to identify and confirm the original species of aluminium ions (Al3+ ) dissolved in water, since they behave differently. Depending on their species, the toxicity differs. Capillary electrophoresis (CE) coupled with electrospray ionization mass spectrometry (ESI-MS) and CE coupled with inductively coupled plasma mass spectrometry (CE/ICP-MS) were explored to identify and determine simple systems of Al species solutions at pH 3.0. METHODS: The new combinations of techniques, namely, ESI-MS coupled with CE for identification of species and ICP-MS coupled with CE for confirmation, were applied to for the analyses of Al and fluoride (F) solutions. RESULTS: Al monomers, some Al dimers and trimers were detected by CE/ESI-MS. CE/ICP-MS experiments were conducted with the assembled interface. As a result, the calibration line showed R2 = 0.9856, and the detection limits were 35 nL and 0.037 µM. The results were compared with data obtained using MINEQL+. CONCLUSIONS: Most of the Al species detected were monomers; some dimers and trimers were detected by CE/ESI-MS, but they were not detected by CE-ICP-MS, probably owing to extremely low concentrations. The Al speciation technique was improved by CE/ESI-MS, and the Al species present at extremely low concentrations were ascertained by CE/ICP-MS. The use of coupled instruments will be one of the most powerful tools for identifying dissolved metal ions.

N-terminal pro-brain natriuretic Peptide as a useful diagnostic marker of acute Kawasaki disease in children.

BACKGROUND: Serum N-terminal pro-brain natriuretic peptide (NTproBNP) is often elevated in patients with acute Kawasaki disease (KD), but the NTproBNP level in normal children is higher than in adults. Thus, characterization of the normal levels and cut-off values of NTproBNP according to age is warranted for proper diagnosis of acute KD in children. METHODS AND RESULTS: Six hundred and fifty-five patients aged 1 month-15 years (median, 2.9 years) were included. Patients were admitted to the NTT East Japan Sapporo Hospital between October 2007 and October 2011. Serum NTproBNP level was examined in 149 patients with KD (median, 2.1 years) and 506 control patients with acute infectious disease (median, 3.2 years). In the control group, a Z-score curve of NTproBNP was generated for each age group using least mean square-based methods. The Z-score distribution of KD patients was then compared with that of the control group. The specificity and sensitivity of NTproBNP for diagnosing acute KD were 97.8% and 47.0%, respectively, at Z-score >2.0. Additionally, simple cut-offs every 100 pg/ml according to age were established for more convenient use at the bedside. CONCLUSIONS: The Z-score curve for NTproBNP in children was characterized. A Z-score >2.0 or the cut-off for children may be used to diagnose acute KD.