Association between smoking and central sensitization pain: a web-based cross-sectional study.

PURPOSE: This study aimed to investigate whether smoking is an independent risk factor for central sensitization syndrome (CSS) in individuals with pain as measured by the Central Sensitization Inventory (CSI). METHODS: In 2020, we conducted an Internet survey targeting 2000 ordinary residents of Japan (aged 20-69 years) who had pain symptoms from October to November 2020. A multiple regression analysis was performed on the association between smoking status (nonsmokers and current smokers; Brinkman index) and CSI values. Moreover, compared to nonsmokers, the relative risk (RR) of the CSI cut-off score of 40 points or higher among current smokers was calculated using a modified Poisson regression model. Covariates included age, sex, body mass index, marital status, equivalized income, exercise habits, history of hypertension, history of hyperlipidemia, history of diabetes, pain chronicity, and Pain Catastrophizing Scale score. RESULTS: This study analyzed 1,822 individuals (1,041 men and 781 women). Among those experiencing pain, current smoking was associated with the increase in CSI values (ß = 0.07). The Brinkman index was also significantly associated with the increase in CSI values (ß = 0.06). Current smoking also increased the risk of being over the CSI cut-off score, with a relative risk (RR) of 1.29 (95% confidence intervals, 1.04-1.60). Younger age, being women, experiencing chronic pain, and higher pain catastrophizing thinking were also significantly associated with increased CSS severity, independent of smoking status. CONCLUSION: Smoking is an independent risk factor for CSS. This indicates that smoking may be an important factor in the management of central pain disorders.

Death receptor 6 contributes to autoimmunity in lupus-prone mice.

Expansion of autoreactive follicular helper T (Tfh) cells is tightly restricted to prevent induction of autoantibody-dependent immunological diseases, such as systemic lupus erythematosus (SLE). Here we show expression of an orphan immune regulator, death receptor 6 (DR6/TNFRSF21), on a population of Tfh cells that are highly expanded in lupus-like disease progression in mice. Genome-wide screening reveals an interaction between syndecan-1 and DR6 resulting in immunosuppressive functions. Importantly, syndecan-1 is expressed specifically on autoreactive germinal centre (GC) B cells that are critical for maintenance of Tfh cells. Syndecan-1 expression level on GC B cells is associated with Tfh cell expansion and disease progression in lupus-prone mouse strains. In addition, Tfh cell suppression by DR6-specific monoclonal antibody delays disease progression in lupus-prone mice. These findings suggest that the DR6/syndecan-1 axis regulates aberrant GC reactions and could be a therapeutic target for autoimmune diseases such as SLE.

Type-I interferon is critical for FasL expression on lung cells to determine the severity of influenza.

Infection of influenza A virus in mammals induces hyper lung pneumonia, which often causes lethal diseases. FasL is a specific ligand of Fas, which is a type-I transmembrane protein to induce cell death. Previously, it has been reported that the hyper induction of gene expression associated with Fas signal is observed in lethal influenza A virus infection. More importantly, it was also reported that functional mutation of the FasL gene protects the host against influenza A virus infection. These observations suggest that induction of FasL signal is functionally associated with the severity of influenza. However, regulation of the induction of FasL or Fas by influenza A virus infection is still unknown. Here, we demonstrated that FasL is induced after the viral infection, and inhibition of the Fas/FasL signal by treatment with a recombinant decoy receptor for FasL (Fas-Fc) increases the survival rate of mice after lethal infection of influenza A virus as well as functional mutation of the FasL gene in gld/gld mice. In addition, the induction level of FasL gene expression in the lung was correlated with the severity of influenza. We also showed that a variety of types of cells in the lung express FasL after the viral infection. Furthermore, type-I interferon induced by the viral infection was shown to be critical for induction of FasL protein expression in the lung. These findings suggested that expression of FasL protein induced by type-I IFN on the lung cell surface is critical to determine the severity of influenza.

LKB1 is crucial for TRAIL-mediated apoptosis induction in osteosarcoma.

BACKGROUND: Despite improvements in chemotherapy and surgery in the treatment of osteosarcoma, satisfactory results are still difficult to achieve. New therapeutic modalities need to be developed for the improvement of these treatments. TRAIL (TNF-related apoptosis inducing ligand) is known as a selective apoptosis inducer in most tumor cells, but not in normal cells. Therefore, TRAIL is a good candidate target for the treatment of tumors. However, sensitivity of osteosarcoma cells to TRAIL-induced apoptosis is lower than that of other types of tumor cells. Recently, DAP3 (death associated protein 3) was demonstrated to play a critical role in TRAIL-mediated apoptosis through activation of pro-caspase-8. Here, we found that LKB1, a serine/threonine kinase, expressed in bone and soft tissue sarcoma cells, associated with DAP3. We also demonstrated that expression of DAP3 induced apoptosis in osteosarcoma cells. Furthermore, expression of LKB1 induced apoptosis and co-expression of LKB1 with DAP3 strongly induced apoptosis in osteosarcoma cells. In addition, expression of LKB1 kinase dead mutant, LKB1 (K78M), inhibited DAP3-induced apoptosis in these cells. These results suggest that LKB1 is critical for TRAIL-induced apoptosis induction, cooperating with DAP3 in osteosarcoma cells. It is predicted that LKB1 and DAP3 could be critical target molecules for the treatment of osteosarcomas.

Naloxone reversal of opioid anesthesia revisited: clinical evaluation and plasma concentration analysis of continuous naloxone infusion after anesthesia with high-dose fentanyl.

PURPOSE: In spite of several advantages, the need for postoperative ventilatory support limits the use of high-dose opioid anesthesia. We prospectively evaluated the effectiveness of naloxone infusion for the reversal of high-dose fentanyl anesthesia. METHODS: Anesthesia was maintained with fentanyl in patients undergoing major abdominal surgery. After anesthesia, the trachea was extubated when intravenous naloxone, which was titrated in separate 50- micro g doses, established an acceptable level of consciousness and arterial blood gas (ABG) status under spontaneous respiration; this was followed by continuous infusion started at the rate of the sum of the bolus doses per hour. The naloxone infusion was terminated based on evaluation of the level of consciousness, ABG, and acute abstinence symptoms. Postoperative pain was evaluated using self-reported four-step categorical terms (none, mild, moderate, and severe). Plasma concentrations of fentanyl and naloxone were analyzed in 12 patients, using high-performance liquid chromatography. RESULTS: Fifty-seven out of 59 eligible patients were successfully extubated at 34 +/- 14 min after termination of fentanyl (total dose, 127 +/- 64 micro g.kg(-1); mean +/- SD) with naloxone (total bolus, 3.4 +/- 2.6 micro g.kg(-1)). All these patients recovered fully without ventilatory support under the naloxone infusion, which was terminated at 11 +/- 7 h. The reduction of the naloxone infusion rate effectively relieved the increased pain, and no supplemental analgesic was used in any patients during the naloxone infusion. Pharmacokinetic analysis did not indicate any correlations between plasma fentanyl and naloxone concentrations. CONCLUSION: The results suggest that naloxone infusion with individual dose titration facilitates the use of high-dose opioid anesthesia, maintaining the advantager of this anesthesia.