PubMed Health⌕ Search

Biomedical subjects

Giuseppe Cirino

Publications and source records attributed to Giuseppe Cirino.

At least 19 recordsLinked to original sources
PubMed2006

Synthesis of 2-methyl-3-indolylacetic derivatives as anti-inflammatory agents that inhibit preferentially cyclooxygenase 1 without gastric damage.

Novel substituted 2-methyl-3-indolylacetic derivatives were synthesized and evaluated for their activity in vitro and in vivo on COX-1 and COX-2. Active compounds were screened to determine their gastrointestinal tolerability in vivo in the rat. Results showed that 3 and 4 preferentially inhibited COX-1 in vitro and in vivo. MD simulations indicated an induced fit for COX-1 but not for COX-2, probably because of a lower plasticity of the latter.

Acute Disease↗
PubMed2006

A new modified thrombin binding aptamer containing a 5'-5' inversion of polarity site.

The solution structure of a new modified thrombin binding aptamer (TBA) containing a 5'-5' inversion of polarity site, namely d(3'GGT5'-5'TGGTGTGGTTGG3'), is reported. NMR and CD spectroscopy, as well as molecular dynamic and mechanic calculations, have been used to characterize the 3D structure. The modified oligonucleotide is characterized by a chair-like structure consisting of two G-tetrads connected by three edge-wise TT, TGT and TT loops. d(3'GGT5'-5'TGGTGTGGTTGG3') is characterized by an unusual folding, being three strands parallel to each other and only one strand oriented in opposite manner. This led to an anti-anti-anti-syn and syn-syn-syn-anti arrangement of the Gs in the two tetrads. The thermal stability of the modified oligonucleotide is 4 degrees C higher than the corresponding unmodified TBA. d(3'GGT5'-5'TGGTGTGGTTGG3') continues to display an anticoagulant activity, even if decreased with respect to the TBA.

Aptamers, Nucleotide↗
PubMed2006

Hydrogen sulfide is an endogenous modulator of leukocyte-mediated inflammation.

Hydrogen sulfide (H2S) is increasingly recognized as an important signaling molecule in the cardiovascular and nervous systems. Recently, H2S donors were reported to induce neutrophil apoptosis and to suppress expression of some leukocyte and endothelial adhesion molecules. Using rats, we examined the possibility that H2S is an endogenous regulator of key inflammatory events at the leukocyte-endothelial interface. Via intravital microscopy, we observed that H2S donors (NaHS and Na2S) inhibited aspirin-induced leukocyte adherence in mesenteric venules (ED50 of 5.0 micromol/kg for Na2S), likely via activation of ATP-sensitive K+ (K(ATP)) channels. Inhibition of endogenous H2S synthesis elicited leukocyte adherence. Leukocyte infiltration in an air pouch model was also suppressed by H2S donors (NaHS, Lawesson's reagent, and N-acetylcysteine; ED50 of 42.7, 1.3, and 29.9 micromol/kg, respectively) and exacerbated by inhibition of endogenous H2S synthesis. Carrageenan-induced paw edema was suppressed by H2S donors (NaHS and Na2S; ED50s of 35 and 28 micromol/kg, respectively) to the same extent as by diclofenac and enhanced by an inhibitor of H2S synthesis. Suppression of edema formation by H2S donors was mimicked by a K(ATP) channel agonist and reversed by an antagonist of this channel. These results suggest that endogenous H2S is an important mediator of acute inflammation, acting at the leukocyte-endothelium interface. These findings have important implications for anti-inflammatory drug development.

Animals↗
PubMed2006

5-Amino-2-hydroxybenzoic acid 4-(5-thioxo-5H-[1,2]dithiol-3yl)-phenyl ester (ATB-429), a hydrogen sulfide-releasing derivative of mesalamine, exerts antinociceptive effects in a model of postinflammatory hypersensitivity.

H(2)S functions as a neuromodulator and exerts anti-inflammatory activities. Recent data indicate that irritable bowel syndrome (IBS) is linked to inflammation of the gastrointestinal tract. In this study, we have investigated the role of a novel H(2)S-releasing derivative of mesalamine (5-amino-2-hydroxybenzoic acid 4-(5-thioxo-5H-[1,2]dithiol-3yl)-phenyl ester, ATB-429) in modulating nociception to colorectal distension (CRD), a model that mimics some features of IBS, in healthy and postcolitic rats. Four graded (0.4-1.6 ml of water) CRDs were produced in conscious rats, and colorectal sensitivity and pain were assessed by measuring the abdominal withdrawal response and spinal c-Fos expression. In healthy rats, ATB-429 dose dependently (25, 50, or 100 mg/kg) attenuated CRD-induced hypersensitivity and significantly inhibited CRD-induced overexpression of spinal c-FOS mRNA, whereas mesalamine had no effect. ATB-429-induced antinociception was reversed by glibenclamide, a ATP-sensitive K(+) (K(ATP)) channel inhibitor. The antinociceptive effect of ATB-429 was maintained in a rodent model of postinflammatory hypersensitivity (4 weeks after colitis induction). At a dose of 100 mg/kg, ATB-429 reversed the allodynic response caused by CRD in postcolitic rats. Colonic cyclooxygenase-2 and interkeukin-1beta mRNA and spinal c-FOS mRNA expression were significantly down-regulated by ATB-429, but not by mesalamine. ATB-429, but not mesalamine, increased blood concentrations of H(2)S in both healthy and postcolitic rats. Taken together, these data suggest that ATB-429 inhibits hypersensitivity induced by CRD in both healthy and postcolitic, allodynic rats by a K(ATP) channel-mediated mechanism. This study provides evidence that H(2)S-releasing drugs might have beneficial effects in the treatment of painful intestinal disorders.

Analgesics↗
PubMed2006

Proteinase-activated receptors (PARs): crossroads between innate immunity and coagulation.

Coagulation cascade and innate immunity are intimately linked in their endeavor to organize the body's response to injury. Protease-activated receptors (PARs) are important mediators of inflammatory response that can be activated by proteases of the coagulation cascade. Their recent discovery has shed new light on the crosstalk between coagulation and innate immunity. Recent studies have investigated the physiological relevance of PARs in the context of immunity and vascular injury, suggesting that these receptors could be used as therapeutic targets for the treatment of pathologies related to innate immunity, endothelial functions and coagulation processes.

Animals↗
PubMed2006

Total synthesis and biological evaluation of halipeptins A and D and analogues.

The marine-derived halipeptins A (1a) and D (1d) and their analogues 3a, 3d and 4a, 4d were synthesized starting from building blocks 10, 13, 14a or 14d, 15, and 16. The first strategy for assembling the building blocks, involving a macrolactamization reaction to form the 16-membered ring hydroxy thioamide 52d as a precursor, furnished the epi-isoleucine analogue (4d) of halipeptin D, whereas a second approach involving thiazoline formation prior to macrolactamization led to a mixture of halipeptins A (1a) and D (1d) and their analogues 3a, 3d (epimers at the indicated site) and 4a, 4d (epimers at the indicated site). The same route starting with D-Ala resulted in the exclusive formation of the epimeric halipeptin D analogue 3d. The synthesized halipeptins, together with the previously constructed oxazoline analogues 5d and 6d, were subjected to biological evaluation revealing anti-inflammatory properties for 1a, 1d, and 6d while being noncytotoxic against human colon cancer cells (HCT-116).

Anti-Infective Agents↗
PubMed2006

The emerging roles of hydrogen sulfide in the gastrointestinal tract and liver.

Hydrogen sulfide, like nitric oxide, was best known as a toxic pollutant before becoming recognized as a key regulator of several physiologic processes. In recent years, evidence has accumulated to suggest important roles for hydrogen sulfide as a mediator of several aspects of gastrointestinal and liver function. Moreover, alterations in hydrogen sulfide production could contribute to disorders of the gastrointestinal tract and liver. For example, nonsteroidal anti-inflammatory drugs can reduce production of hydrogen sulfide in the stomach, and this has been shown to contribute to the generation of mucosal injury. Hydrogen sulfide has also been shown to play a key role in modulation of visceral hyperalgesia. Inhibitors of hydrogen sulfide synthesis and drugs that can generate safe levels of hydrogen sulfide in vivo have been developed and are permitting interventional studies in experimental models and, in the near future, humans.

Air Pollutants↗
PubMed2006

Pharmacology of erectile dysfunction in man.

Erectile dysfunction (ED) is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity (2nd International Consultation on Sexual Dysfunction-Paris, June 28th-July 1st, 2003). Following the discovery and introduction of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost and many preclinical and clinical papers have been published in the last 5 years. This review is structured in order to give the reader an overview of the clinical and preclinical data available on the peripheral regulation of and the mediators involved in human penile erection. The most widely accepted risk factors for ED are discussed. The article is focused on human data, and the safety and effectiveness of the 3 commercially available Phosphodiesterase-5 (PDE5) inhibitors used to treat ED are also discussed.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2006

Evidence for differential expression of Notch receptors and their ligands in melanocytic nevi and cutaneous malignant melanoma.

The Notch signaling has been implicated in the regulation of self-renewal of adult stem cells and differentiation of precursors along a specific cell lineage, in normal embryonic development and organogenesis. There is also evidence that signaling through Notch receptors regulate cell proliferation and cell survival in several types of cancer, with opposing results depending on tissue context. No data are available in the literature concerning modulation of the expression of Notch receptors, and their ligands, in human cutaneous malignant melanoma. Here, we have investigated, for the first time, the expression of Notch-1, Notch-2, Jagged-1, Jagged-2 and Delta-like 1 proteins, by immunohistochemistry, in a series of benign and malignant human melanocytic lesions: five common melanocytic nevi, five 'dysplastic nevi' and 20 melanomas (five in situ, five T1-T2, five T3-T4 and five metastatic melanomas). We found that the expression of Notch-1 and Notch-2, as well as Notch ligands, was upregulated in 'dysplastic nevi' and melanomas as compared with common melanocytic nevi. These results indicate that the activation of Notch may represent an early event in melanocytic tumor growth and upregulation of Notch signaling may sustain tumor progression.

Adult↗
PubMed2006

Thrombin inhibits IFN-gamma production in human peripheral blood mononuclear cells by promoting a Th2 profile.

Thrombin, the key enzyme of the coagulation cascade, is involved in inflammation. It was proposed recently that thrombin activity may play an important role in allergic inflammation. Interferon-gamma (IFN-gamma) is a potent Th1-related cytokine secreted by activated T cells and is usually downregulated in allergic inflammation. We recently demonstrated that thrombin enhances interleukin-10 (IL-10) in peripheral blood mononuclear cells (PBMC). Thus, we hypothesized that thrombin may promote a Th2 profile. We here report that human alpha- thrombin downregulates IFN-gamma expression at both protein and mRNA levels in activated PBMCs. The use of proteolytically inactive thrombin and of the specific thrombin receptor agonist peptide, SFLLRN, shows that this downregulation is thrombin specific and requires thrombin proteolytic activity. The addition of an anti- IL-10 monoclonal antibody (mAb) to thrombin-treated PBMCs abolishes IFN-gamma downregulation, suggesting that thrombin exerts its effect through IL-10, a Th2-related cytokine. Furthermore, IFN-gamma reduction was accompanied by increased IL-4 release, as well as by an increase in the proinflammatory cytokine IL-1. In conclusion, the observation that thrombin affects the production of IFN-gamma (Th1 profile) and IL-4 (Th2 profile) provides further evidence for the role played by thrombin in modulating Th1/Th2 cytokine balance, which could be particularly relevant in allergic inflammation.

Cells, Cultured↗
PubMed2006

Nitric oxide and inflammation.

There are several pre-clinical studies on the involvement of NO in inflammation. From this large amount of information it is clear that virtually every cell and many immunological parameters are modulated by NO. Thus, the final outcome is that NO cannot be rigidly classified as an anti-inflammatory or pro-inflammatory molecule. This peculiar aspect of the pathophysiology of NO has hampered the development of new drugs based on the concepts developed. Recent therapeutic approach are targeted to increase endogenous NO by activating the gene and some promising early data are available. At the present stage one of the most promising approach in the inflammation field is represented by a new class of NO-releasing compounds namely NO-NSAIDs that have recently enrolled in phase 2 clinical studies.

Acetaminophen↗
PubMed2005

Essential requirement for sphingosine kinase activity in eNOS-dependent NO release and vasorelaxation.

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that acts both as an extracellular ligand for endothelial differentiation gene receptor family and as an intracellular second messenger. Cellular levels of S1P are low and tightly regulated by sphingosine kinase (SPK). Recent studies have suggested that eNOS pathway may function as a downstream target for the biological effects of receptor-mediated S1P. Here we have studied the possible interplay between intracellular SIP generation and the eNOS activation pathway. S1P causes an endothelium-dependent vasorelaxation in rat aorta that is PTX sensitive, inhibited by L-NAME that involves eNOS phosphorylation, and mainly dependent on hsp90. When rat aorta rings were incubated with the SPK inhibitor DL-threo-dihydrosphingosine (DTD), there was a concentration-dependent reduction of Ach-induced vasorelaxation, implying a consistent contribution of sphingolipid pathway through intracellular sphingosine release and phosphorylation. Co-immunoprecipitation experiments consistently showed increased association of hsp90 with eNOS after exposure of cells to S1P as well to BK or calcium ionophore A-23187. Interestingly, as opposite to A-23187, BK and S1P effect were significantly inhibited by pretreatment with the SPK inhibitor DTD. In conclusion, our data demonstrate that an interplay exists among eNOS, hsp90, and intracellularly generated S1P where eNOS coupling to hsp90 is a major determinant for NO release as confirmed by our functional and molecular studies.

Animals↗
PubMed2005

A protective role for proteinase activated receptor 2 in airways of lipopolysaccharide-treated rats.

Proteinase activated receptor-2 (PAR2), a seven transmembrane domain G protein coupled receptor, is expressed on airway epithelium and smooth muscle cells and over-expressed in human airways under pathological conditions, such as asthma and chronic obstructive pulmonary disease (COPD). However, the role of PAR2 in airways has not yet been defined. Aim of the present study, was to evaluate the in vitro rat bronchial response to a synthetic peptide activating PAR2 (PAR2-AP; SLIGRL), following an in vivo treatment with bacterial lipopolysaccharide (LPS). Bronchi from LPS-treated animals showed an increased relaxant response to PAR2-AP, compared to naïve animals, the effect was maximum after 20-h pre-treatment and reduced by epithelium removal. Western blot analysis showed an increased PAR2 protein expression on bronchi removed 20h after LPS treatment. PAR2-AP-induced bronchorelaxation was inhibited by ibuprofen, by the selective cyclooxygenase2 (COX-2) inhibitor, diisopropyl fluorophosphate (DFP) and partially by the calcitonin gene related peptide (CGRP) antagonist, rat-CGRP([8-37]). Furthermore, there was a strong immunoreactivity for COX-2 on bronchial epithelium of LPS-treated rats. Prostaglandin E2 (PGE2) tissue release and CGRP tissue content were significantly increased following tissue incubation with PAR2-AP. The in vivo LPS treatment in rats strongly increases the bronchorelaxant effect of PAR2-AP, this effect correlates with an increased tissue protein receptor expression and the COX-2 localization on bronchial epithelium. Our work supports a role for PAR2 as a defence mechanism aimed to preserve bronchial functionality under systemic inflammatory conditions; both COX-2-derived PGE2 and CGRP are involved in this effect.

Animals↗
PubMed2005

Sphingosine 1-phosphate induces endothelial nitric-oxide synthase activation through phosphorylation in human corpus cavernosum.

Sphingosine 1-phosphate (S1P) is the natural ligand for a specific G protein-coupled receptors. In endothelial cells, S1P has been shown to modulate the activity of the endothelial nitric-oxide synthase (eNOS) through phosphorylation operated by Akt. Nitric oxide (NO) produced by neuronal nitric-oxide synthase and eNOS plays a central role in triggering and maintaining penile erection. This study has assessed the possibility of a similar cross-talk between eNOS and S1P in human corpus cavernosum and whether this interaction is connected to penile vascular response. Quantitative reverse transcription-polymerase chain reaction demonstrated the presence of S1P(1), S1P(2), and S1P(3) receptors in both the human corpus cavernosum (HCC) and the penile artery. S1P on its own did not relax or contract HCC strips, but on the other hand, incubation with S1P (0.1 microM) caused a 6-fold increase in relaxation induced by a subliminal dose of acetylcholine. This effect is dependent upon eNOS activation through an Akt-dependent phosphorylation, as demonstrated by pharmacological modulation with l-nitroarginine methyl ester and wortmannin and by Western blot studies. In human tissue, S1P seems to be the possible candidate for the activation of the eNOS calcium-independent pathway. This pathway may represent a new therapeutic area of intervention in erectile dysfunction (ED) to develop a way to selectively promote NO production at the endothelial level. This approach could also be used to enhance phosphodiesterase 5 therapy in patients with ED that are poor responders, such as in the case of diabetes.

Endothelium, Vascular↗
PubMed2005

Evidence that hydrogen sulfide exerts antinociceptive effects in the gastrointestinal tract by activating KATP channels.

Hydrogen sulfide (H(2)S) functions as a neuromodulator, but whether it modulates visceral perception and pain is unknown. Cystathionine beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) mediate enzymatic generation of H(2)S in mammalian cells. Here we have investigated the role of H(2)S in modulating nociception to colorectal distension, a model that mimics some features of the irritable bowel syndrome. Four graded (0.4-1.6 ml of water) colorectal distensions (CRDs) were produced in conscious rats (healthy and postcolitic), and rectal nociception was assessed by measuring the behavioral response during CRD. Healthy rats were administered with sodium hydrogen sulfide (NaHS) (as a source of H(2)S), L-cysteine, or vehicle. In a second model, we investigated nociception to CRD in rats recovering from a chemically induced acute colitis. We found that CBS and CSE are expressed in the colon and spinal cord. Treating rats with NaHS resulted in a dose-dependent attenuation of CRD-induced nociception with the maximal effect at 60 micromol/kg (p < 0.05). Administration of L-cysteine, a CSE/CBS substrate, reduced rectal sensitivity to CRD (p < 0.05). NaHS-induced antinociception was reversed by glibenclamide, a ATP-sensitive K(+) (K(ATP)) channel inhibitor, and N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME), a nitric-oxide (NO) synthase inhibitor. The antinociceptive effect of NaHS was maintained during the resolution of colon inflammation induced by intrarectal administration of a chemical irritant. In summary, these data show that H(2)S inhibits nociception induced by CRD in both healthy and postcolitic rats. This effect is mediated by K(ATP) channels and NO. H(2)S-releasing drugs might be beneficial in treating painful intestinal disorders.

ATP-Binding Cassette Transporters↗
PubMed2005

Protease-activated receptor-2 (PAR2) in cardiovascular system.

Vascular system is constituted by a complex and articulate network, e.g. arteries, arterioles, venules and veins, that requires a high degree of coordination between different elemental cell types. Proteinase-activated receptors (PARs) constitute a recent described family of 7-transmembrane G protein-coupled receptors that are activated by proteolysis. In recent years several evidence have been accumulated for an involvement of this receptor in the response to endothelial injury in vitro and in vivo experimental settings suggesting a role for PAR2 in the pathophysiology of cardiovascular system. This review will deal with the role of PAR2 receptor in the cardiovascular system analyzing both in vivo and in vitro published data. In particular this review will deal with the role of this receptor in vascular reactivity, ischemia/reperfusion injury, coronary atherosclerotic lesions and angiogenesis.

Animals↗
PubMed2005

Proteinase-activated receptor-2 mediates arterial vasodilation in diabetes.

OBJECTIVE: Proteinase-activated receptor-2 is widely expressed in vascular tissue and in highly vascularized organs in humans and other species. Its activation mainly causes endothelium-dependent vasorelaxation in vitro and hypotension in vivo. Here, using nonobese diabetic (NOD) mice at different disease stages, we have evaluated the role of PAR2 in the arterial vascular response during diabetes progression. METHODS AND RESULTS: High (NOD-II; 20 to 500 mg/dL) or severe glycosuria (NOD-III; 500 to 1000 mg/dL) provokes a progressive reduction in the response to acetylcholine paralleled by an increase in the vasodilatory response to PAR2 stimulation. Western blot and quantitative real-time polymerase chain reaction (RT-PCR) studies showed that this effect is tied to an increased expression of PAR2 coupled to cyclooxygenase-2 expression. Pharmacological dissection performed with specific inhibitors confirmed the functional involvement of cyclooxygenase-2 in PAR2 vasodilatory effect. This vasodilatory response was confirmed to be dependent on expression of PAR2 in the smooth muscle component by immunohistochemistry studies performed on aorta isolated by both NOD-III and transgenic PAR2 mice. CONCLUSIONS: Our data demonstrate an important role for PAR2 in modulating vascular arterial response in diabetes and suggest that this receptor could represent an useful therapeutic target.

Animals↗