LASSBio-1135: A Dual TRPV1 Antagonist and Anti-TNF-Alpha Compound Orally Effective in Models of Inflammatory and Neuropathic Pain

<div><p>LASSBio-1135 is an imidazo[1,2-a]pyridine derivative with high efficacy in screening models of nociception and inflammation, presumed as a weak COX-2 inhibitor. In order to tease out its mechanism of action, we investigated others possible target for LASSBio-1135, such as TNF-α and TRPV1, to better characterize it as a multitarget compound useful in the treatment of chronic pain. TRPV1 modulation was assessed in TRPV1-expressing Xenopus oocytes against capsaicin and low pH-induced current. Modulation of TNF-α production was evaluated in culture of macrophages stimulated with LPS. <i>In vivo</i> efficacy of LASSBio-1135 was investigated in carrageenan and partial sciatic ligation-induced thermal hyperalgesia and mechanical allodynia. Corroborating its previous demonstration of efficacy in a model of capsaicin-induced hyperalgesia, LASSBio-1135 blocks capsaicin-elicited currents in a non-competitive way with an IC₅₀ of 580 nM as well as low pH-induced current at 50 µM. As an additional action, LASSBio-1135 inhibited TNF-α release in these cells stimulated by LPS with an IC₅₀ of 546 nM by reducing p38 MAPK phosphorilation. Oral administration of 100 µmol.Kg⁻¹ LASSBio-1135 markedly reduced thermal hyperalgesia induced by carrageenan, however at 10 µmol.Kg⁻¹ only a partial reduction was observed at the 4^th h. Neutrophil recruitment and TNF-α production after carrageenan stimulus was also inhibited by the treatment with LASSBio-1135. Modulating TRPV1 and TNF-α production, two key therapeutic targets of neuropathic pain, 100 µmol.Kg⁻¹ LASSBio-1135 was orally efficacious in reversing thermal hyperalgesia and mechanical allodynia produced by partial sciatic ligation 7–11 days after surgery without provoking hyperthermia, a common side effect of TRPV1 antagonists. In conclusion LASSBio-1135, besides being a weak COX-2 inhibitor, is a non-competitive TRPV1 antagonist and a TNF-α inhibitor. As a multitarget compound, LASSBio-1135 is orally efficacious in a model of neuropathic pain without presenting hyperthermia.</p></div

LASSBio-1135 chronic treatment did not promote hyperthermia.

<p>Animals submitted to partial sciatic ligation and daily treated with vehicle or LASSBio-1135 (100 µmol.Kg⁻¹, p.o.) had their rectal temperature measured 1 hour after compound administration. Delta (Δ) of temperature was obtained comparing the measures of temperature obtained before and after surgery. Results are expressed as mean ± SEM (<i>n</i> = 6–8 animals).</p

LASSBio-1135 is orally effective in reducing thermal and mechanical hypersensitivity induced by partial sciatic ligation.

<p>A) LASSBio-1135 (100 µmol.Kg⁻¹; p.o.) inhibits thermal hyperalgesia induced by a radiant heat light source. Delta (Δ) of latency was obtained by comparing times of withdrawal before and after surgery. B) LASSBio-1135 (100 µmol.Kg⁻¹; p.o.) also inhibits mechanical allodynia induced by Von Frey filaments. The compound was daily administered from day 5 until day 13 after surgery, 1 hour before evaluation of thermal and mechanical hypersensitivity. The withdrawal responses were determined beginning 5 days after the surgery. C) LASSBio-1135 (100 µmol.Kg⁻¹; p.o.) did not affect baseline thermal sensibility induced by a radiant heat light source. Compound or vehicle were administered and evaluation of thermal sensitivity was performed at subsequent 1, 2, 3, 4 and 6 h. Results are expressed as mean ± SEM and analysed using Two-way ANOVA followed by Bonferroni post-test (<i>n</i> = 6–8 animals; *p<0.05 compared to vehicle group).</p

LASSBio-1135 inhibits carrageenan-induced thermal hyperalgesia by reducing TNF-α production and neutrophils infiltration in the injured paw.

<p>A) Oral pre-treatment with LASSBio-1135 at 10 and 100 µmol.Kg⁻¹ 1 hour before carrageenan injection into the paw, reduces thermal hyperalgesia at different time points.Results were analyzed using Two-way ANOVA followed by Bonferroni post-test. (<i>n</i> = 6–8 animals per group, *p<0.05 compared to vehicle group). B) 4 hours after stimulus with carrageenan paws were removed and neutrophils migration was quantified by MPO activity. LASSBio-1135 treatment also reduces neutrophils migration Results were analyzed using One-way ANOVA followed by Dunnett post-test (<i>n</i> = 4 animals per group, *p<0.05 compared to vehicle group). C) The same tissue samples were used to quantify TNF-α production. LASSBio-1135 oral treatment with 10 µmol.Kg⁻¹ and 100 µmol.Kg⁻¹ also reduced TNF-α production in the injured paw Results were analyzed using One-way ANOVA followed by Dunnett post-test (<i>n</i> = 3–4 animals per group, *p<0.05 compared to vehicle group).</p

LASSBio-1135 inhibits TNF-α production in murine macrophages stimulated with LPS by blockade of p38 MAPK signaling pathway.

<p>A) Representative graph showing that LASSBio-1135 inhibits TNF-α release by macrophages stimulated with LPS (100 ng.ml⁻¹) at three different concentrations. Results were analyzed using One-way ANOVA followed by Dunnett post-test (<i>n</i> = 3–4 experiments per group, *p<0.05 compared to DMSO group). B) Concentration-response curve of LASSBio-1135. The IC₅₀ estimated was 642 nM (<i>n</i> = 3–4 experiments per concentration). D) LASSBio-1135 interferes with cell viability only at 100 µM. Results were analyzed using One-way ANOVA followed by Dunnett post-test (<i>n</i> = 3–4 experiments per group, *p<0.05 compared to DMSO group) C) LASSBio-1135 reduces p38 MAPK activation induced by LPS in a concentration-dependent fashion. Results were analyzed using One-way ANOVA followed by Dunnett post-test (<i>n</i> = 3 experiments per group, *p<0.05 compared to DMSO group).</p

The National Student Survey: validation in Portuguese medical students

The UK National Student Survey (NSS) is a sound and widely used instrument for assessing students’ academic experiences. We aimed to translate the NSS for Portuguese students and to validate the instrument in a sample of medical undergraduates. The research team translated and adapted the NSS for Portuguese students (NSS-P). The survey was administered on an online platform to 1,256 final-year students at eight Portuguese medical schools. A total of 329 medical students (69.9% female) replied to the NSS-P, a response rate of 26.2%. Confirmatory factor analysis showed that the original six-factor structure had an adequate fit to the data. Adequate internal consistency was observed for all the subscales. Medium to large correlations were found among all the subscale scores and between the subscale scores and the students’ overall satisfaction. Multiple regression showed that the scores on the Teaching, Organization and Management and Personal Development subscales significantly predicted the students’ overall satisfaction. Approximately 64% of the students reported being satisfied with the quality of their courses. Significant differences among the medical schools in their NSS-P scores were found. The NSS-P is a valid and reliable measure for assessing medical students’ perceptions of academic quality