RESUMEN
BACKGROUND: Concurrent sensitization to peanut (PN) and tree nuts (TN), the most dangerous food allergies, is common. Current oral immunotherapy (OIT) is not fully satisfactory. OBJECTIVE: To determine whether the herbal formula B-FAHF-2 (BF2) ameliorates PN/TN OIT adverse reactions and enhances persistence of a tolerant state. METHODS: Concurrently sensitized PN-, walnut- (WN) and cashew (CSH)-allergic mice received 1-day PN/WN/CSH rush OIT plus 3 weeks of maintenance dosing, with or without 3 weeks prior and 3 weeks BF2 co-treatment. Anaphylactic symptom scores, core body temperatures, plasma histamine levels, basophil numbers, antigen-specific IgE, cytokine levels, and IL-4, INF-γ and Foxp3 gene promoter DNA methylation status, and their correlation with final challenge symptom scores were determined. RESULTS: BF2+OIT-treated mice experienced significantly fewer and less severe adverse reactions than OIT-only-treated mice (P<.01) during the 1-day rush OIT build-up dose phase. Both OIT-only and BF2+OIT mice showed significant desensitization (P<.01 and .001, respectively) at 1 week post-therapy challenge, being greater in BF2+OIT mice. All sham-treated and 91% of OIT-treated mice experienced anaphylaxis whereas only 21% of BF2+OIT-treated mice exhibited reactions during 5-6 weeks of dose escalation single PN and TN challenges. Greater and more persistent protection in BF2+OIT mice was associated with significantly lower plasma histamine and IgE levels, increased IFN-γ/IL-4 and IL-10/IL-4 ratios, DNA remethylation at the IL-4 promoter and demethylation at IFN-γ and Foxp3 promoters. Final challenge symptom scores were inversely correlated with IL-4 DNA methylation levels (P<.0002) and positively correlated with IFN-γ and Foxp3 gene promoter methylation levels (P<.0011) (P<.0165). CONCLUSIONS AND CLINICAL RELEVANCE: Combined BF2/OIT therapy was safer and produced longer post-treatment protection and more tolerance-prone immunological and epigenetic modifications than OIT alone. BF2/OIT may provide an additional OIT option for patients with concurrent PN/TN and other food allergies.
Asunto(s)
Inmunoterapia/métodos , Hipersensibilidad a la Nuez , Hipersensibilidad al Cacahuete , Preparaciones de Plantas/farmacología , Administración Oral , Animales , Modelos Animales de Enfermedad , Femenino , Factores de Transcripción Forkhead/inmunología , Inmunoglobulina E/inmunología , Interferón gamma/inmunología , Interleucina-4/inmunología , Ratones , Hipersensibilidad a la Nuez/inmunología , Hipersensibilidad a la Nuez/patología , Hipersensibilidad a la Nuez/terapia , Hipersensibilidad al Cacahuete/inmunología , Hipersensibilidad al Cacahuete/patología , Hipersensibilidad al Cacahuete/terapiaRESUMEN
The presence of pairs of basic amino acids within the orphanin FQ/Nociceptin (OFQ/N) sequence has raised the possibility that truncated versions of the peptide might be physiologically important. OFQ/N(1-11) is pharmacologically active in mice, despite its poor affinity in binding assays (K(i) > 250 nM) for the OFQ/N receptor. Using an analog of OFQ/N(1-11), [(125)I][Tyr(10)]OFQ/N(1-11), we identified a high-affinity binding site (K(D) 234 pM; B(max) 43 fmol/mg protein) with a selectivity profile distinct from the OFQ/N receptor and all the traditional opioid receptors. This site had very high affinity for OFQ/N and its related peptides. The most striking differences between the new site and the OFQ/N receptor previously observed in brain were seen with traditional opioids. Dynorphin A analogs and alpha-neoendorphin competed with [(125)I][Tyr(10)]OFQ/N(1-11) binding in mouse brain with K(i) values below 10 nM, while naloxone benzoylhydrazone (K(i) 3.9 nM) labeled the [(125)I][Tyr(10)]OFQ/N(1-11) binding site as potently as many traditional opioid receptors. Several other opioids, including fentanyl, (-)cyclazocine, levallorphan, naltrindole, and diprenorphine, also displayed moderate affinities for this site. Finally, the [(125)I][Tyr(10)]OFQ/N(1-11) site had a unique regional distribution consistent with a distinct receptor. Thus, [(125)I][Tyr(10)]OFQ/N(1-11) labels a novel site in brain with a selectivity profile intermediate between that of either opioid or OFQ/N receptors.
Asunto(s)
Sitios de Unión/efectos de los fármacos , Química Encefálica , Péptidos Opioides/farmacología , Receptores Opioides/metabolismo , Animales , Autorradiografía , Sitios de Unión/fisiología , Dinorfinas/farmacología , Ratones , Ratones Endogámicos , Narcóticos/farmacología , Péptidos Opioides/análisis , Ensayo de Unión Radioligante , Vasodilatadores/farmacología , Receptor de Nociceptina , NociceptinaRESUMEN
The presence of pairs of basic amino acids within the sequence of orphanin FQ/nociceptin (OFQ/N) peptide, the endogenous ligand for the ORL1/KOR-3 receptor, has raised the possibility that processing might generate pharmacologically important truncated peptides, including OFQ/N(1-11). OFQ/N(1-11) is pharmacologically active in vivo with a potency comparable to OFQ/N. Several tyrosine-containing analogs of OFQ/N(1-11) have been synthesized and examined for antinociceptive activity. Like OFQ/N(1-11), [Tyr1]OFQ/N(1-11), [Tyr10]OFQ/N(1-11) and [IodoTyr10]OFQ/N(1-11) given supraspinally in mice were antinociceptive in the tailflick assay in mice. The tyrosine analogs showed similar potencies as OFQ/N(1-11) but longer durations of action. This response was readily reversed by the opioid antagonist naloxone despite poor affinities for these analogs at opioid receptors. Another compound, [Tyr11]OFQ/N(1-11) was highly epileptogenic, inducing naloxone-sensitive seizures in greater than 50% of the mice tested at doses comparable to those examined with the other analogs. These results indicate that it is possible to make analgesic OFQ/N(1-11) analogs. The activity of [IodoTyr10]OFQ/N(1-11) suggests that it may prove useful as a radioligand in exploring potential OFQ/N(1-11) binding sites.
Asunto(s)
Nociceptores/efectos de los fármacos , Péptidos Opioides/farmacología , Animales , Masculino , Ratones , Ratones Endogámicos , Fragmentos de Péptidos/farmacología , Receptores Opioides/agonistas , NociceptinaRESUMEN
The recently isolated peptides endomorphin-1 and endomorphin-2 have been suggested to be the endogenous ligands for the mu receptor. In traditional opioid receptor binding assays in mouse brain homogenates, both endomorphin-1 and endomorphin-2 competed both mu1 and mu2 receptor sites quite potently. Neither compound had appreciable affinity for either delta or kappa1 receptors, confirming an earlier report. However, the two endomorphins displayed reasonable affinities for kappa3 binding sites, with Ki values between 20 and 30 nM. Both endomorphins competed 3H-[D-Ala2, MePhe4,Gly(ol)5] enkephalin binding to MOR-1 receptors expressed in CHO cells with high affinity. In mouse brain homogenates 125I-endomorphin-1 and 125I-endomorphin-2 binding was selectively competed by mu ligands. 125I-Endomorphin-1 and 125I-endomorphin-2 also labeled MOR-1 receptors expressed in CHO cells with high affinity. Autoradiography of the two 125I-labeled endomorphins demonstrated regional patterns in the brain similar to those previously observed for mu drugs. Pharmacologically, the endomorphins were potent analgesics. Although they were equipotent supraspinally, endomorphin-1 was more potent spinally. Endomorphin analgesia was effectively blocked by naloxone, as well as the mu-selective antagonists beta-funaltrexamine and naloxonazine. In CXBK mice, which are insensitive to supraspinal morphine, neither endomorphin was active, consistent with a mu mechanism of action. Finally, the endomorphins inhibited gastrointestinal transit. In conclusion, these results support the mu selectivity of these agents.
Asunto(s)
Analgésicos Opioides/farmacología , Encéfalo/efectos de los fármacos , Oligopéptidos/farmacología , Analgésicos Opioides/farmacocinética , Animales , Autorradiografía , Células CHO , Cricetinae , Tránsito Gastrointestinal , Inyecciones Intraventriculares , Radioisótopos de Yodo , Masculino , Membranas/efectos de los fármacos , Membranas/metabolismo , Ratones , Ratones Endogámicos , Oligopéptidos/farmacocinética , Dimensión del Dolor/efectos de los fármacos , Receptores Opioides mu/agonistas , Receptores Opioides mu/efectos de los fármacosRESUMEN
Neuronal activity causes local changes in cerebral blood flow, blood volume, and blood oxygenation. Magnetic resonance imaging (MRI) techniques sensitive to changes in cerebral blood flow and blood oxygenation were developed by high-speed echo planar imaging. These techniques were used to obtain completely noninvasive tomographic maps of human brain activity, by using visual and motor stimulus paradigms. Changes in blood oxygenation were detected by using a gradient echo (GE) imaging sequence sensitive to the paramagnetic state of deoxygenated hemoglobin. Blood flow changes were evaluated by a spin-echo inversion recovery (IR), tissue relaxation parameter T1-sensitive pulse sequence. A series of images were acquired continuously with the same imaging pulse sequence (either GE or IR) during task activation. Cine display of subtraction images (activated minus baseline) directly demonstrates activity-induced changes in brain MR signal observed at a temporal resolution of seconds. During 8-Hz patterned-flash photic stimulation, a significant increase in signal intensity (paired t test; P less than 0.001) of 1.8% +/- 0.8% (GE) and 1.8% +/- 0.9% (IR) was observed in the primary visual cortex (V1) of seven normal volunteers. The mean rise-time constant of the signal change was 4.4 +/- 2.2 s for the GE images and 8.9 +/- 2.8 s for the IR images. The stimulation frequency dependence of visual activation agrees with previous positron emission tomography observations, with the largest MR signal response occurring at 8 Hz. Similar signal changes were observed within the human primary motor cortex (M1) during a hand squeezing task and in animal models of increased blood flow by hypercapnia. By using intrinsic blood-tissue contrast, functional MRI opens a spatial-temporal window onto individual brain physiology.