Prevention of methamphetamine-induced microglial cell death by TNF-α and IL-6 through activation of the JAK-STAT pathway

<p><b>Abstract</b></p> <p><b>Background</b></p> <p>It is well known that methamphetamine (METH) is neurotoxic and recent studies have suggested the involvement of neuroinflammatory processes in brain dysfunction induced by misuse of this drug. Indeed, glial cells seem to be activated in response to METH, but its effects on microglial cells are not fully understood. Moreover, it has been shown that cytokines, which are normally released by activated microglia, may have a dual role in response to brain injury. This led us to study the toxic effect of METH on microglial cells by looking to cell death and alterations of tumor necrosis factor-alpha (TNF-α) and interleukine-6 (IL-6) systems, as well as the role played by these cytokines.</p> <p><b>Methods</b></p> <p>We used the N9 microglial cell line, and cell death and proliferation were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling assay and incorporation of bromodeoxyuridine, respectively. The TNF-α and IL-6 content was quantified by enzyme-linked immunosorbent assay, and changes in TNF receptor 1, IL-6 receptor-alpha, Bax and Bcl-2 protein levels by western blotting. Immunocytochemistry analysis was also performed to evaluate alterations in microglial morphology and in the protein expression of phospho-signal transducer and activator of transcription 3 (pSTAT3).</p> <p><b>Results</b></p> <p>METH induced microglial cell death in a concentration-dependent manner (EC₅₀ = 1 mM), and also led to significant morphological changes and decreased cell proliferation. Additionally, this drug increased TNF-α extracellular and intracellular levels, as well as its receptor protein levels at 1 h, whereas IL-6 and its receptor levels were increased at 24 h post-exposure. However, the endogenous proinflammatory cytokines did not contribute to METH-induced microglial cell death. On the other hand, exogenous low concentrations of TNF-α or IL-6 had a protective effect. Interestingly, we also verified that the anti-apoptotic role of TNF-α was mediated by activation of IL-6 signaling, specifically the janus kinase (JAK)-STAT3 pathway, which in turn induced down-regulation of the Bax/Bcl-2 ratio.</p> <p><b>Conclusions</b></p> <p>These findings show that TNF-α and IL-6 have a protective role against METH-induced microglial cell death via the IL-6 receptor, specifically through activation of the JAK-STAT3 pathway, with consequent changes in pro- and anti-apoptotic proteins.</p

The stigma of low opioid prescription in the hospitalized multimorbid elderly in Italy

The primary aim of this study was to evaluate the prevalence of opioid prescriptions in hospitalized geriatric patients. Other aims were to evaluate factors associated with opioid prescription, and whether or not there was consistency between the presence of pain and prescription. Opioid prescriptions were gathered from the REgistro POliterapie Societa` Italiana di Medicina Interna (REPOSI) data for the years 2008, 2010 and 2012. 1,380 in-patients, 65+ years old, were enrolled in the first registry run, 1,332 in the second and 1,340 in the third. The prevalence of opioid prescription was calculated at hospital admission and discharge. In the third run of the registry, the degree of pain was assessed by means of a numerical scale. The prevalence of patients prescribed with opioids at admission was 3.8\ua0% in the first run, 3.6\ua0% in the second and 4.1\ua0% in the third, whereas at discharge rates were slightly higher (5.8, 5.3, and 6.6\ua0%). The most frequently prescribed agents were mild opioids such as codeine and tramadol. The number of total prescribed drugs was positively associated with opioid prescription in the three runs; in the third, dementia and a better functional status were inversely associated with opioid prescription. Finally, as many as 58\ua0% of patients with significant pain at discharge were prescribed no analgesic at all. The conservative attitude of Italian physicians to prescribe opioids in elderly patients changed very little between hospital admission and discharge through a period of 5\ua0years. Reasons for such a low opioid prescription should be sought in physicians\u2019 and patients\u2019 concerns and prejudices