Hit optimization of the class of quinazoline containing histamine H4 receptor (H4R) ligands resulted in a sulfonamide substituted analogue with high affinity for the H4R. This moiety leads to ...improved physicochemical properties and is believed to probe a distinct H4R binding pocket that was previously identified using pharmacophore modeling. By introducing a variety of sulfonamide substituents, the H4R affinity was optimized. The interaction of the new ligands, in combination with a set of previously published quinazoline compounds, was described by a QSAR equation. Pharmacological studies revealed that the sulfonamide analogues have excellent H4R affinity and behave as inverse agonists at the human H4R. In vivo evaluation of the potent 2-(6-chloro-2-(4-methylpiperazin-1-yl)quinazoline-4-amino)-N-phenylethanesulfonamide (54) (pK i = 8.31 ± 0.10) revealed it to have anti-inflammatory activity in an animal model of acute inflammation.
The effects of the highly selective histamine H4 receptor antagonists JNJ7777120 and VUF6002 were investigated on the carrageenan-induced inflammation and thermal hyperalgesia in rats. JNJ7777120 (10 ...and 30 mg/kg, s.c.) and VUF6002 (10 mg/kg, s.c.) significantly reduced paw edema and hyperalgesia provoked by subplantar injection of carrageenan; the effect was evident against the early (2 h) phase of inflammation. An inactive analog of VUF6002, VUF6007 (10 mg/kg, s.c.) slightly aggravated paw edema, while leaving unaltered carrageenan-induced nociception. These findings indicate that histamine H4 receptors participate in the early phase of acute inflammation induced by carrageenan in rats, influencing both edema and thermal hyperalgesia.
The location and functional role of histamine H4 receptors (H4Rs) in the gastrointestinal tract (GI) is reviewed, with particular reference to their involvement in the regulation of gastric acid ...secretion, gastric mucosal defense, intestinal motility and secretion, visceral sensitivity, inflammation, immunity and carcinogenesis. H4Rs have been detected in different cell types of the gut, including immune cells, paracrine cells, endocrine cells and neurons; moreover, H4R expression was reported in human colorectal cancer specimens. Functional studies with selective H4R ligands demonstrated protective effects in several experimental models of gastric mucosal damage and intestinal inflammation, suggesting a potential therapeutic role of drugs targeting this new receptor subtype in GI disorders, such as allergic enteropathy, inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and cancer.
From a series of small fragments that was designed to probe the histamine H4 receptor (H4R), we previously described quinoxaline-containing fragments that were grown into high affinity H4R ligands in ...a process that was guided by pharmacophore modeling. With a scaffold hopping exercise and using the same in silico models, we now report the identification and optimization of a series of quinazoline-containing H4R compounds. This approach led to the discovery of 6-chloro-N-(furan-3-ylmethyl)2-(4-methylpiperazin-1-yl)quinazolin-4-amine (VUF10499, 54) and 6-chloro-2-(4-methylpiperazin-1-yl)-N-(thiophen-2-ylmethyl)quinazolin-4-amine (VUF10497, 55) as potent human H4R inverse agonists (pK i = 8.12 and 7.57, respectively). Interestingly, both compounds also possess considerable affinity for the human histamine H1 receptor (H1R) and therefore represent a novel class of dual action H1R/H4R ligands, a profile that potentially leads to added therapeutic benefit. Compounds from this novel series of quinazolines are antagonists at the rat H4R and were found to possess anti-inflammatory properties in vivo in the rat.
: The effects of the histamine H4 receptor antagonist JNJ7777120 were evaluated in a model of acute skin inflammation induced by local application of croton oil. The influence of strain on the ...effect of JNJ7777120 was investigated in four different mouse strains (CD‐1, NMRI, BALB/c and C57BL/6J). In CD‐1 mice, JNJ777720 (30–100 mg/kg subcutaneously, s.c.) exerted a dose‐dependent inhibition of croton oil‐induced ear inflammation and polymorphonuclear leucocyte infiltration, as confirmed by histological evaluation of ear tissues. JNJ7777120 (30–100 mg/kg) did not reduce ear oedema in NMRI, BALB/c or C57BL/6J mice. The positive control, dexamethasone (2 mg/kg s.c.) induced significant anti‐inflammatory effects only in CD‐1 and NMRI mice. In these strains, also the histamine H1‐receptor blocker pyrilamine (30 mg/kg s.c.) significantly reduced ear oedema at 2 h after croton oil challenge, being as effective as JNJ7777120 in CD‐1 mice. Taken together, these data demonstrate that the H4 receptor antagonist JNJ7777120 may reduce acute croton oil‐induced skin inflammation as effectively as H1 receptor blockade. However, present experiments evidenced for the first time marked strain‐related differences in the JNJ7777120 pharmacological activity, which have to be carefully considered when using this ligand to characterize histamine H4 receptor functions in murine models and translating preclinical data to clinical human settings.
It is now widely recognized that nonsteroidal anti-inflammatory drugs (NSAIDs) may cause extensive damage to the intestine. The pathogenesis of NSAID-induced intestinal injury, however, is still ...controversial and both local irritant actions and cyclooxygenase (COX) inhibition have been proposed as underlying mechanisms. In this study we investigated further on NSAID-induced intestinal damage by using nonselective (indomethacin and ibuprofen), COX-1 selective (SC-560) or COX-2 selective (celecoxib) inhibitors. NSAIDs were administered orally to conscious rats and small intestinal injury was evaluated 24 h afterwards in terms of macroscopic and microscopic alterations, myeloperoxidase activity, lipid peroxidation, number of enterobacteria in the mucosa and epithelial mucin content. Oral administration of indomethacin (20 mg/kg) induced macroscopic and microscopic damage to the small intestine, increased translocation of enterobacteria from lumen into the mucosa, myeloperoxidase activity and lipid peroxidation. Ibuprofen (120 mg/kg), SC-560 (20 mg/kg), celecoxib (60 mg/kg) or the combination of SC-560 plus celecoxib did not cause any intestinal injury nor modified the number of bacteria in mucosal homogenates. SC-560 significantly increased both myeloperoxidase activity and lipid peroxidation, whereas celecoxib significantly reduced myeloperoxidase levels, while leaving unaltered lipid peroxidation. Finally, all NSAIDs, mostly indomethacin, increased neutral mucins and decreased acidic mucins in the intestinal goblet cells. These results indicate that inhibition of cyclooxygenase, although variably influencing mucosal integrity homeostasis, is not sufficient to initiate acute intestinal damage in rats. Moreover, topical mucosal injury induced by the NSAID molecule seems to be a critical factor in the development of intestinal injury.
Proton pump inhibitors (PPIs) have been shown to be effective in preventing gastric and duodenal ulcers in high-risk patients taking nonsteroidal anti-inflammatory drugs (NSAIDs); by contrast, scarce ...information is available concerning the effects of PPIs on intestinal damage induced by NSAIDs in humans or in experimental animals. We examined the effects of lansoprazole and omeprazole on the intestinal injury induced by indomethacin in the conscious rat. PPIs were administered by the intragastric route at 30, 60 and 90 micromol/kg, 12 h and 30 min before and 6 h after indomethacin treatment. The effects of omeprazole and lansoprazole were evaluated on: (1) macroscopic and histologic damage; (2) mucosal polymorphonuclear cell infiltration; (3) oxidative tissue damage and (4) bacterial translocation from lumen into the intestinal mucosa. Lansoprazole and omeprazole (at 90 micromol/kg) significantly decreased (P<0.01) the macroscopic and histologic damage induced by indomethacin in the rat small intestine. Furthermore, both drugs greatly reduced (P<0.01) the associated increases in myeloperoxidase levels and lipid peroxidation induced by indomethacin, whereas they only moderately affected (P<0.05) the translocation of enterobacteria from lumen into the intestinal mucosa. These data demonstrate that omeprazole and lansoprazole can protect the small intestine from the damage induced by indomethacin in the conscious rat. The intestinal protection, possibly related to antioxidant and anti-inflammatory properties of these drugs, may suggest new therapeutic uses of PPIs in intestinal inflammatory diseases.
Background and purpose: We compare the pharmacological profiles of a new histamine H4 receptor agonist 2‐(2‐guanidinoethyl)isothiourea (VUF 8430) with that of a previously described H4 receptor ...agonist, 4‐methylhistamine.
Experimental approach: Radioligand binding and functional assays were performed using histamine H4 receptors expressed in mammalian cell lines. Compounds were also evaluated ex vivo in monocyte‐derived dendritic cells endogenously expressing H4 receptors and in vivo in anaesthetized rats for gastric acid secretion activity.
Key results: Both VUF 8430 and 4‐methylhistamine were full agonists at human H4 receptors with lower affinity at rat and mouse H4 receptors. Both compounds induced chemotaxis of monocyte‐derived dendritic cells. VUF 8430 also showed reasonable affinity and was a full agonist at the H3 receptor. Agmatine is a metabolite of arginine, structurally related to VUF 8430, and was a H4 receptor agonist with micromolar affinity. At histamine H3 receptors, agmatine was a full agonist, whereas 4‐methylhistamine was an agonist only at high concentrations. Both VUF 8430 and agmatine were inactive at H1 and H2 receptors, whereas 4‐methylhistamine is as active as histamine at H2 receptors. In vivo, VUF 8430 only caused a weak secretion of gastric acid mediated by H2 receptors, whereas 4‐methylhistamine, dimaprit, histamine and amthamine, at equimolar doses, induced 2.5‐ to 6‐fold higher output than VUF 8430.
Conclusions and implications: Our results suggest complementary use of 4‐methylhistamine and VUF 8430 as H4 receptor agonists. Along with H4 receptor antagonists, both agonists can serve as useful pharmacological tools in studies of histamine H4 receptors.
Pharmacological therapy of back pain with analgesics and anti-inflammatory drugs is frequently associated with adverse effects, particularly in the elderly. Aim of this study was to compare ...mesotherapic versus conventional systemic administration of nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids in patients with acute low back pain. Eighty-four patients were randomized to receive anti-inflammatory therapy according to the following protocols: (a) mesotherapy group received the 1st and 4th day 2% lidocaine (1 mL) + ketoprofen 160 mg (1 mL) + methylprednisolone 40 mg (1 mL), then on 7th, 10th, and 13th day, 2% lidocaine (1 mL) + ketoprofen 160 mg (1 mL) + methylprednisolone 20 mg (1 mL) (b) conventional therapy group received ketoprofen 80 mg × 2/die and esomeprazole 20 mg/die orally for 12 days, methylprednisolone 40 mg/die intramuscularly for 4 days, followed by methylprednisolone 20 mg/die for 3 days, and thereafter, methylprednisolone 20 mg/die at alternate days. Pain intensity and functional disability were assessed at baseline (T0), at the end of treatment (T1), and 6 months thereafter (T2) by using visual analogic scale (VAS) and Roland-Morris disability questionnaire (RMDQ). In both groups, VAS and RMDQ values were significantly reduced at the end of drug treatment and after 6 months, in comparison with baseline. No significant differences were found between the two groups. This suggests that mesotherapy may be a valid alternative to conventional therapy in the treatment of acute low back pain with corticosteroids and NSAIDs.
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