Dietary zinc restriction promotes degeneration of the endocrine pancreas in mice.

Zinc is a key component of several proteins, interacting with the pancreatic hormones insulin and amylin. The role of zinc in insulin oligomerization and crystallinity is well established, although the effects of dietary zinc restriction on both energetic metabolism and ß-pancreatic hormonemia and morphology remain unexplored. Here we report the effects of dietary zinc restriction on the endocrine pancreas and metabolic phenotype of mice. Nontransgenic male Swiss mice were fed a low-zinc or control diet for 4 weeks after weanling. Growth, glycemia, insulinemia and amylinemia were lower and pancreatic islets were smaller in the intervention group despite the preserved insulin crystallinity in secretory granules. We found strong immunostaining for insulin, amylin and oligomers in apoptotic pancreatic islet. High production of ß-pancreatic hormones in zinc-restricted animals counteracted the reduced islet size caused by apoptosis. These data suggest that zinc deficiency is sufficient to promote islet ß-cell hormonal disruption and degeneration.

Long-Chain Omega-3 Fatty Acids Supplementation Accelerates Nerve Regeneration and Prevents Neuropathic Pain Behavior in Mice.

Fish oil (FO) is the main source of long chain omega-3 polyunsaturated fatty acids (ω-3 PUFAs), which display relevant analgesic and anti-inflammatory properties. Peripheral nerve injury is driven by degeneration, neuroinflammation, and neuronal plasticity which results in neuropathic pain (NP) symptoms such as allodynia and hyperalgesia. We tested the preventive effect of an EPA/DHA-concentrate fish oil (CFO) on NP development and regenerative features. Swiss mice received daily oral treatment with CFO 4.6 or 2.3 g/kg for 10 days after NP was induced by partial sciatic nerve ligation. Mechanical allodynia and thermal hypernociception were assessed 5 days after injury. CFO 2.3 g/kg significantly prevented mechanical and thermal sensitization, reduced TNF levels in the spinal cord, sciatic MPO activity, and ATF-3 expression on DRG cells. CFO improved Sciatic Functional Index (SFI) as well as electrophysiological recordings, corroborating the increased GAP43 expression and total number of myelinated fibers observed in sciatic nerve. No locomotor activity impairment was observed in CFO treated groups. These results point to the regenerative and possibly protective properties of a combined EPA and DHA oral administration after peripheral nerve injury, as well as its anti-neuroinflammatory activity, evidencing ω-3 PUFAs promising therapeutic outcomes for NP treatment.

LASSBio-1135: a dual TRPV1 antagonist and anti-TNF-alpha compound orally effective in models of inflammatory and neuropathic pain.

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. In vivo 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 x Kg(-1) LASSBio-1135 markedly reduced thermal hyperalgesia induced by carrageenan, however at 10 µmol x Kg(-1) only a partial reduction was observed at the 4th 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 x 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.

Discovery of novel orally active anti-inflammatory N-phenylpyrazolyl-N-glycinyl-hydrazone derivatives that inhibit TNF-α production.

Herein, we describe the synthesis and pharmacological evaluation of novel N-phenylpyrazolyl-N-glycinyl-hydrazone derivatives that were designed as novel prototypes of p38 mitogen-activated protein kinase (MAPK) inhibitors. All of the novel synthesized compounds described in this study were evaluated for their in vitro capacity to inhibit tumor necrosis factor α (TNF-α production in cultured macrophages) and in vitro MAPK p38α inhibition. The two most active anti-TNF-α derivatives, (E)-2-(3-tert-butyl-1-phenyl-1H-pyrazol-5-ylamino)-N'-((4-(2-morpholinoethoxy)naphthalen-1-yl)methylene)acetohydrazide (4a) and (E)-2-(3-tert-butyl-1-phenyl-1H-pyrazol-5-ylamino)-N'-(4-chlorobenzylidene)acetohydrazide (4f), were evaluated to determine their in vivo anti-hyperalgesic profiles in carrageenan-induced thermal hypernociception model in rats. Both compounds showed anti-inflammatory and antinociceptive properties comparable to SB-203580 used as a standard drug, by oral route at a dose of 100 µmol/kg. This bioprofile is correlated with the ability of NAH derivatives (4a) and (4f) suppressing TNF-α levels in vivo by 57.3 and 55.8%, respectively.

Discovery of novel analgesic and anti-inflammatory 3-arylamine-imidazo[1,2-a]pyridine symbiotic prototypes.

We describe herein the design, synthesis and pharmacological evaluation of novel 3-arylamine-imidazo[1,2-a]pyridine derivatives structurally designed as novel symbiotic prototypes presenting analgesic and anti-inflammatory properties. The derivatives obtained were submitted to in vivo assays of nociception, hyperalgesia and inflammation, and to in vitro assays of human PGHS-2 inhibition. These assays allowed the identification of compound LASSBio-1135 (3a) as an anti-inflammatory and analgesic symbiotic prototype. This compound inhibited moderately the human PGHS-2 enzyme activity (IC(50)=18.5 microM) and reverted the capsaicin-induced thermal hyperalgesia (100 micromol/kg, po) similarly to p38 MAPK inhibitor SB-203580 (2). Additionally, LASSBio-1135 (3a) presented activity similar to celecoxib (1) regarding the reduction of the carrageenan-induced rat paw edema (33% of inhibition at 100 micromol/kg, po). We also discovered derivatives LASSBio-1140 (3c) and LASSBio-1141 (3e) as analgesic and anti-inflammatory prototypes, which were able to attenuate the capsaicin-induced thermal hyperalgesia (100 micromol/kg, po) and reduce the carrageenan-induced paw edema (ED(50)=11.5 micromol/kg (3.3mg/kg) and 14.5 micromol/kg (4.1mg/kg), respectively), being both more active than celecoxib (1), despite the fact that their effects involve a different mechanism of action. Additionally, derivative LASSBio-1145 (3j) showed remarkable analgesic (ED(50)=22.7 micromol/kg (8.9 mg/kg)) and anti-inflammatory (ED(50)=8.7 micromol/kg (3.4 mg/kg)) profile in vivo (100 micromol/kg; po), in AcOH-induced abdominal constrictions in mice and carrageenan-induced rat paw edema models, respectively, being a novel orally-active anti-inflammatory drug candidate that acts as a selective PGHS-2 inhibitor (IC(50)=2.8 microM).