Nociceptin receptor activation inhibits tachykinergic non adrenergic non cholinergic contraction of guinea pig isolated bronchus

We studied the action of nociceptin (NC) on the atropine-resistant contractions of the guinea pig isolated bronchus evoked by the electrical field stimulation (EFS), an effect that is mediated by the activation of excitatory non adrenergic-non cholinergic (eNANC) nerves and the subsequent release of tachykinins. The functional site by which NC acts in this preparation was investigated using few different NC receptor agonists and the newly discovered NC receptor antagonist, [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2 ([F/G]NC(1-13)NH2). NC inhibited in a concentration dependent manner (pEC50 7.14; Em - 87 +/- 3% of control values) EFS induced contractions. NC effect was mimicked by the NC analogues, NCNH2 and NC(1-13)NH2, but not by NC(1-9)NH2. NC (1 microM) did not affect the contractile effects of exogenously applied neurokinin A (1 microM). [F/G]NC(1-13)NH2 (10 microM) completely prevented the inhibition induced by NC (1 microM), whereas naloxone (1 microM) was found inactive. Both naloxone and ([F/G]NC(1-13)NH2 were per se inactive on basal resting tone as well as on the electrically induced contractions. The present findings show that NC inhibits the atropine-resistant EFS-induced contraction in the guinea pig bronchus by inhibiting eNANC nerves, and suggest the presence of NC receptors, distinct from opioid receptors, on the nerves of the guinea pig bronchus.     

Agonists of proteinase-activated receptor 2 induce inflammation by a neurogenic mechanism

Trypsin and mast cell tryptase cleave proteinase-activated receptor 2 and, by unknown mechanisms, induce widespread inflammation. We found that a large proportion of primary spinal afferent neurons, which express proteinase-activated receptor 2, also contain the proinflammatory neuropeptides calcitonin gene-related peptide and substance P. Trypsin and tryptase directly signal to neurons to stimulate release of these neuropeptides, which mediate inflammatory edema induced by agonists of proteinase-activated receptor 2. This new mechanism of protease-induced neurogenic inflammation may contribute to the proinflammatory effects of mast cells in human disease. Thus, tryptase inhibitors and antagonists of proteinase-activated receptor 2 may be useful anti-inflammatory agents.     

Telangiectasia as a presenting sign of Graves' disease

Acquired nevoid telangiectasia (ANT) is observed in several conditions including primary cutaneous disorders, systemic autoimmune disease and hyperestrogenism occurring in puberty, pregnancy and chronic liver disease. We describe a patient in whom ANT was a presenting sign of autoimmune hyperthyroidism, which improved after thyroidectomy. A 43-year-old Caucasian woman experienced an asymptomatic development of multiple widespread red skin lesions, diagnosed to be ANT. Blood tests revealed increased serum levels of free tri-iodothyronine and thyroxine and suppressed thyroid-stimulating hormone. Other causes of ANT were excluded. ANT improved but did not disappear after thyroidectomy. The possible pathogenetic factors linking ANT and Graves' disease, such as an immune-mediated process, altered estrogen metabolism or vasodilatation associated with hyperdynamic circulation, are discussed.     

Rituximab Effectiveness and Safety for Treating Primary Sj?gren’s Syndrome (pSS): Systematic Review and Meta-Analysis

Background

Primary Sjögren’s Syndrome (pSS) is a systemic autoimmune disease that involves the exocrine glands and internal organs. pSS leads to destruction and loss of secretory function due to intense lymphoplasmacytic infiltration. Therapeutic options include mainly symptomatic and supportive measures, and traditional immunosuppressant drugs have shown no effectiveness in randomized trials. Rituximab (RTX) is a chimeric antibody anti-CD20 that leads to B cell depletion by diverse mechanisms. There is evidence that this drug may be effective for treating pSS. The objective of this systematic review was to evaluate Rituximab effectiveness and safety for treating pSS.

Methods and Findings

We conducted a systematic review of RCTs published until December 2015, with no language restriction. We registered a protocol on Plataforma Brasil (40654814.6.0000.5505) and developed search strategies for the following scientific databases: MEDLINE, EMBASE, CENTRAL and LILACS. We included adults with established pSS diagnosis and considered the use of Rituximab as intervention and the use of other drugs or placebo as control. Four studies met our eligibility criteria: three with low risk of bias and one with uncertain risk of bias. The total number of participants was 276 (145 RTX, 131 placebo). We assessed the risk of bias of each included study and evaluated the following as primary outcomes: lacrimal gland function, salivary gland function, fatigue improvement and adverse events. We found no significant differences between the groups in the Schirmer test at week 24 meta-analysis (MD 3.59, 95% CI -2.89 to 10.07). Only one study evaluated the lissamine green test and reported a statistically significant difference between the groups at week 24 (MD -2.00, 95% CI -3.52 to -0.48). There was a significant difference between the groups regarding salivary flow rate (MD 0.09, 95% CI 0.02 to 0.16) and improvement in fatigue VAS at weeks 6 (RR 3.98, 95% CI 1.61 to 9.82) and week 16 (RR 3.08, 95% CI 1.21 to 7.80).

Conclusions

According to moderate quality evidence, the treatment with a single RTX course in patients with SSp presents discrete effect for improving lacrimal gland function. Low-quality evidence indicates the potential of this drug for improving salivary flow. According to low quality evidence, no differences were observed in the evaluation after 24 weeks regarding fatigue reduction (30% VAS), serious adverse events occurrence, quality of life improvement and disease activity. With a very low level of evidence, there was no improvement in oral dryness VAS evaluation.     

Protease-activated receptor-2 activation exaggerates TRPV1-mediated cough in guinea pigs.

A lowered threshold to the cough response frequently accompanies chronic airway inflammatory conditions. However, the mechanism(s) that from chronic inflammation results in a lowered cough threshold is poorly understood. Irritant agents, including capsaicin, resiniferatoxin, and citric acid, elicit cough in humans and in experimental animals through the activation of the transient receptor potential vanilloid 1 (TRPV1). Protease-activated receptor-2 (PAR2) activation plays a role in inflammation and sensitizes TRPV1 in cultured sensory neurons by a PKC-dependent pathway. Here, we have investigated whether PAR2 activation exaggerates TRPV1-dependent cough in guinea pigs and whether protein kinases are involved in the PAR2-induced cough modulation. Aerosolized PAR2 agonists (PAR2-activating peptide and trypsin) did not produce any cough per se. However, they potentiated citric acid- and resiniferatoxin-induced cough, an effect that was completely prevented by the TRPV1 receptor antagonist capsazepine. In contrast, cough induced by hypertonic saline, a stimulus that provokes cough in a TRPV1-independent manner, was not modified by aerosolized PAR2 agonists. The PKC inhibitor GF-109203X, the PKA inhibitor H-89, and the cyclooxygenase inhibitor indomethacin did not affect cough induced by TRPV1 agonists, but abated the exaggeration of this response produced by PAR2 agonists. In conclusion, PAR2 stimulation exaggerates TRPV1-dependent cough by activation of diverse mechanism(s), including PKC, PKA, and prostanoid release. PAR2 activation, by sensitizing TRPV1 in primary sensory neurons, may play a role in the exaggerated cough observed in certain airways inflammatory diseases such as asthma and chronic obstructive pulmonary disease.     

Anandamide acts as an intracellular messenger amplifying Ca2+ influx via TRPV1 channels

The endocannabinoid anandamide is able to interact with the transient receptor potential vanilloid 1 (TRPV1) channels at a molecular level. As yet, endogenously produced anandamide has not been shown to activate TRPV1, but this is of importance to understand the physiological function of this interaction. Here, we show that intracellular Ca2+ mobilization via the purinergic receptor agonist ATP, the muscarinic receptor agonist carbachol or the Ca(2+)-ATPase inhibitor thapsigargin leads to formation of anandamide, and subsequent TRPV1-dependent Ca2+ influx in transfected cells and sensory neurons of rat dorsal root ganglia (DRG). Anandamide metabolism and efflux from the cell tonically limit TRPV1-mediated Ca2+ entry. In DRG neurons, this mechanism was found to lead to TRPV1-mediated currents that were enhanced by selective blockade of anandamide cellular efflux. Thus, endogenous anandamide is formed on stimulation of metabotropic receptors coupled to the phospholipase C/inositol 1,4,5-triphosphate pathway and then signals to TRPV1 channels. This novel intracellular function of anandamide may precede its action at cannabinoid receptors, and might be relevant to its control over neurotransmitter release.