Gender-related differential effect of tachykinin NK2 receptor-mediated visceral hyperalgesia in guinea pig colon.

BACKGROUND AND PURPOSE: The tachykinin NK2 receptor antagonist ibodutant is under Phase III clinical investigation to treat female patients with irritable bowel syndrome. The aim of this study was to investigate the NK2 receptor-related gender specificity in a model of colitis. EXPERIMENTAL APPROACH: Colitis was induced by rectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS, 0.5 mL, 30 mg·mL(-1) in 30% ethanol) in female and male guinea pigs. Electromyographic recording of the responses to colorectal distension (CRD) was made 3 days later. Ibodutant (0.33 , 0.65, 1.9 and 6.5 mg·kg(-1) ) was given s.c., 30 min before CRD. Release of neurokinin A and substance P from isolated mucosal and smooth muscle tissues following treatment with KCl (80 mM) or capsaicin (10 µM) was measured by EIA. Plasma pharmacokinetics of ibodutant following a single s.c. administration (0.73 or 2.1 mg·kg(-1) ) were measured over 24 h. KEY RESULTS: Ibodutant did not affect abdominal contractions in control animals. After TNBS-induced colitis, ibodutant prevented the increased visceral hypersensitivity to CRD in females, at lower doses than in males. Ibodutant pharmacokinetics did not differ between females and males. Tachykinins release was greater in smooth muscle than in mucosal samples. Capsaicin-stimulated release of tachykinins from inflamed mucosal samples from females was significantly lower than in males. CONCLUSIONS AND IMPLICATIONS: Ibodutant prevented abdominal nociception in a model of visceral hypersensitivity in guinea pigs with a greater efficacy in females than in males. Our results highlight a gender-related difference in colonic visceral hypersensitivity and mucosal nerve activation.

Absorption and metabolism of bioactive molecules after oral consumption of cooked edible heads of Cynara scolymus L. (cultivar Violetto di Provenza) in human subjects: a pilot study.

The current growing interest for natural antioxidants has led to a renewed scientific attention for artichoke, due not only to its nutritional value, but, overall, to its polyphenolic content, showing strong antioxidant properties. The major constituents of artichoke extracts are hydroxycinnamic acids such as chlorogenic acid, dicaffeoylquinic acids caffeic acid and ferulic acid, and flavonoids such as luteolin and apigenin glycosides. In vitro studies, using cultured rat hepatocytes, have shown its hepatoprotective functions and in vivo studies have shown the inhibition of cholesterol biosynthesis in human subjects. Several studies have shown the effect on animal models of artichoke extracts, while information on human bioavailability and metabolism of hydroxycinnamates derivatives is still lacking. Results showed a plasma maximum concentration of 6.4 (SD 1.8) ng/ml for chlorogenic acid after 1 h and its disappearance within 2 h (P< 0.05). Peak plasma concentrations of 19.5 (SD 6.9) ng/ml for total caffeic acid were reached within 1 h, while ferulic acid plasma concentrations showed a biphasic profile with 6.4 (SD1.5) ng/ml and 8.4 (SD4.6) ng/ml within 1 h and after 8 h respectively. We observed a significant increase of dihydrocaffeic acid and dihydroferulic acid total levels after 8 h (P<0.05). No circulating plasma levels of luteolin and apigenin were present. Our study confirms the bioavailability of metabolites of hydroxycinnamic acids after ingestion of cooked edible Cynara scolymus L. (cultivar Violetto di Provenza).

Effect of domestic cooking on human bioavailability of naringenin, chlorogenic acid, lycopene and beta-carotene in cherry tomatoes.

BACKGROUND: Epidemiological data showed that tomato and tomato product (sauce, paste) consumption is associated with a protective effect against the development of some chronic-degenerative diseases. Tomato antioxidant bioactive molecules such as carotenoids and polyphenols could be responsible, at least in part, for the healthy effect observed. The bioavailability of these compounds is an essential requirement to sustain their in vivo role. While it is well known that many factors can influence the bioaccessibility of carotenoids from the food matrix, there is little information about the factors affecting phenolic compounds' bioaccessibility. AIM OF THE STUDY: This investigation was carried out to evaluate the effect of domestic cooking on the bioavailability in humans of antioxidant molecules after the administration of a test meal containing cherry tomatoes. METHODS: A cross-over design was conducted. Subjects (3 females and 2 males) consumed experimental meals containing fresh and cooked cherry tomatoes. Blood collection was performed at different time intervals (0, 2, 4, 6, 8 and 24 h). RESULTS: Carotenoid and phenol plasma concentrations were measured. Plasma levels of lycopene and beta-carotene were not significantly different with respect to the baseline after ingestion of both the test meals, while plasma concentrations of naringenin and chlorogenic acid increased significantly with respect to the baseline (P<0.05) after administration of cooked cherry tomatoes, but not after administration of fresh cherry tomatoes. CONCLUSIONS: The present study indicated that domestically cooked tomatoes significantly increase naringenin and chlorogenic acid plasma levels. Considering that both naringenin and chlorogenic acid are widely studied for their potential healthy properties, evidence of their bioavailability and of the factors influencing their bioaccessibility is an important tool to sustain the possibility that these polyphenols play a biological role in human physiology.

Flavonoids uptake and their effect on cell cycle of human colon adenocarcinoma cells (Caco2).

Green tea, mainly through its constituents epigallocatechin gallate, epigallocatechin, epicatechin gallate and epicatechin, has demonstrated anticarcinogenic activity in several animal models, including those for skin, lung and gastro-intestinal tract cancer, although less is known about colorectal cancer. Quercetin, the major flavonoid present in vegetables and fruit, exerts potential anticarcinogenic effects in animal models and cell cultures, but less is known about quercetin glucosides. The objectives of this study were to investigate (i) the antioxidant activity of the phenolic compounds epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside; (ii) the cytotoxicity of different concentrations of epicatechin, epigallocatechin gallate, and gallic acid; (iii) the cellular uptake of epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside and (iv) their effect on the cell cycle. Human colon adenocarcinoma cells were used as experimental model. The results of this study indicate that all dietary flavonoids studied (epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside) show a significant antioxidant effect in a chemical model system, but only epigallocatechin gallate or gallic acid are able to interfere with the cell cycle in Caco2 cell lines. These data suggest that the antioxidant activity of flavonoids is not related to the inhibition of cellular growth. From a structural point of view, the galloyl moiety appears to be required for both the antioxidant and the antiproliferative effects.

Accumulation and interactions of beta-carotene and alpha-tocopherol in patients with adenomatous polyps.

OBJECTIVE: The aims of the present study were: (1) to determine whether short-term supplementation of beta-carotene (BC) or vitamin E (VE; alpha-tocopherol) would result in their respective accumulation in normal colonic mucosa and in adenomatous polyps; (2) to determine whether the intake of BC would interfere with the concentration of VE in these target tissues. DESIGN: Blood and colonic biopsy samples were taken before and after supplementation. SUBJECTS: Eighteen volunteers with colonic adenomatous polyps were enrolled into this study. INTERVENTIONS: The supplementation lasted for 43 days and patients were examined over the whole period. Subjects were randomised into four groups according to the four different supplementations: placebo, natural BC (25 000 IU/day), natural VE (400 IU/day), combination BC/VE. RESULTS: Initially we were aiming for recruitment of 20 patients in each group, however after 2 y of study (1997-1999), we terminated the study because of slow recruitment and analysed the data. In placebo subjects after supplementation, the plasma concentrations of BC and VE remained unchanged, however only two patients were recruited in this group and therefore we did not include this group in our final analysis. In BC group, the plasma BC concentrations increased significantly (P<0.001), while VE concentrations were unchanged. In VE group, VE concentrations increased (P<0.01) and BC did not change, and in BC/VE group both BC (P<0.001) and VE levels (P<0.01) increased significantly. After supplementation, the tissue concentration of BC in normal colonic mucosa in BC group increased significantly (P<0.01) while the VE concentration did not change. In VE group, the concentration of VE in normal colonic mucosa increased slightly but did not reach statistical significance. However, VE concentration increased significantly (P<0.05) in the polyps of this group. In BC/VE group, in which patients received the combination treatment, the BC concentration of normal colonic mucosa increased (P<0.05) but, surprisingly, the VE concentration decreased significantly (P<0.01). Interestingly in the polyps, although the BC concentration increased (P<0.01), the concentration of VE was reduced moderately but did not reach statistical significance. CONCLUSIONS: Supplementation of BC in doses used in this study may have significantly interfered with the VE concentration in the examined tissue and probably with its metabolic pathway.

Inhibition of delayed hypersensitivity reactions by cinnamyl 1-thioglycosides.

Cinnamyl 1-thio-alpha-D-manno(and L-rhamno)pyranosides have good inhibitory effects in an antigen-specific T cell proliferation assay. The beta anomers are slightly less effective than the alpha anomers. The 6-substituted analogues of cinnamyl 1-thio-alpha-D-mannopyranoside such as 6-deoxy and 6-O-methyl derivatives also block macrophages in presenting the antigen to T cells. D-Mannose and L-rhamnose, when tested by themselves with no modifications, did not block at concentrations up to 1 mM. These cinnamyl 1-thioglycosides when given ip or po at 3-30 mg/kg to mice significantly inhibited the delayed type hypersensitivity reaction as measured by footpad swelling.

Synthetic glycopeptide substrates for receptor-mediated endocytosis by macrophages.

Mammalian macrophages contain a transport system that binds and internalizes glycoproteins with exposed mannose residues. This system and analogous systems on other types of cells require substrates to bear multiple nonreducing terminal residues of the appropriate sugar for effective uptake. Small multivalent synthetic glycopeptides with mannose residues covalently linked through a spacer arm to the alpha- and epsilon-amino groups of lysine, dilysine, and trilysine are competitive inhibitors of rat alveolar macrophage uptake of the neoglycoprotein mannosyl-bovine serum albumin with inhibition constants in the microM range. Various compounds could be covalently attached to the alpha-carboxyl group of these glycopeptides with substantial retention of inhibitory potency. This uptake system does not recognize galactose residues, and the galactosyl analog of an inhibitory mannosylpeptide did not inhibit uptake of mannosyl-bovine serum albumin. The trimannosyldilysine ligand is not only an inhibitor but also a substrate for specific uptake by macrophage, as shown with an 125I-labeled derivative. Macrophages bound 6.4 x 10(5) molecules per cell at 0 degrees C with a dissociation constant of 2 microM. At 21 degrees C the cells could internalize the labeled conjugate with an apparent Michaelis constant of 6 microM and a maximal velocity of 1.7 x 10(5) molecules per min per cel. The dissociation constant and Michaelis constant are similar to the inhibition constant of 9 microM determined at 21 degrees C for inhibition by this conjugate at mannosyl-bovine serum albumin uptake. These synthetic substrates may be useful in targeting pharmacologic agents to macrophages, and analogous compounds may target such agents to other types of cell.

Cell-specific ligands for selective drug delivery to tissues and organs.

Various numbers of D-mannose residues have been attached via spacer arms to lysine, dilysine, and oligolysine backbones. These D-mannosyl peptide analogues were found to be potent competitive inhibitors of the uptake of 125I-labeled D-mannose-bovine serum albumin conjugate by rat alveolar macrophages. The inhibitory potency of these synthetic ligands increased with increasing number of carbohydrate moieties. The chirality of the peptide backbone did not appear to play a major role in binding, whereas variations of the length and linkage of the spacer arm notably affected the inhibitory activities. The saccharide specificity of the macrophage receptor was demonstrated by the inactivity of the corresponding D-galactosyl peptide analogues. The L-fucosyl peptide derivative was only weakly active. The trimannosyldilysine ligand (KI = 3.9 microM) and its analogues are potentially useful in selective delivery of therapeutic agents to macrophages.

Steroidal androgen biosynthesis inhibitors.

PIP: 23,17beta-acylaminoandrost-4-en-3-ones and 3 previously known nonsteroids were synthesized and screened as inhibitors of 17,20-lyase, a step in androgen synthesis from progesterone or OH-progesterone. The screening involved measuring side chain cleavage (carbon-14-acetate release) from 21-carbon-14-17alpha-OH-progesterone by rat testis microsomes. The amide, urea, guanidino and carbamate derivatives were also tested by conversion of cholesterol to pregnenolone by a bovine corpora lutea acetone powder, by conversion of corticosterone to 18-OH-corticosterone by crude adrenal mitochondria, and by feeding to male rats to check effect on adrenal weight and testis testosterone level. More than 80% inhibition was achieved with androst-4-en-3-ones having the C-17beta carbamate, formamido, acetamido and ureido groups. These compounds did not inhibit OH-corticosterone synthesis. 6-alpha methylation inhibited the lyase 50-70%. 1 compound 17-beta-ureidoandrost-1,4-dien-3-one was fed to male rats for 6 weeks at 500 mg per kg; it reduced testis testosterone but not adrenal weight. Selective inhibition of androgen synthesis would be useful for treating benign prostate hypertrophy, hirsutism, acne and androgen dependent tumors.^ieng