Structural Optimization and Characterization of Potent Analgesic Macrocyclic Analogues of Neurotensin (8-13).

The neurotensin receptors are attractive targets for the development of new analgesic compounds. They represent potential alternatives or adjuvants to opioids. Herein, we report the structural optimization of our recently reported macrocyclic peptide analogues of NT(8-13). The macrocycle was formed via ring-closing metathesis (RCM) between an ortho allylated tyrosine residue in position 11 and the side chain of alkene-functionalized amino acid in position 8 of NT(8-13). Minute modifications led to significant binding affinity improvement ( Ki improved from 5600 to 15 nM) with greatly improved plasma stability compared to NT(8-13). This study also delineates the structural features influencing these parameters. The signaling profiles of the new macrocycles were determined on the NTS1 receptor, and the physiological effects of the two most potent and stable analogues were assessed in vivo using rodent models. Both compounds displayed strong analgesic effects.

Supplementation of Blackcurrant Anthocyanins Increased Cyclic Glycine-Proline in the Cerebrospinal Fluid of Parkinson Patients: Potential Treatment to Improve Insulin-Like Growth Factor-1 Function.

BACKGROUND: Insulin-like growth factor-1 (IGF-1) function is impaired in Parkinson disease. Cyclic glycine-proline (cGP), a metabolite of IGF-1, is neuroprotective through improving IGF-1 function. Parkinson disease patients score lower on Hospital-associated Anxiety and Depression Scale after supplementing blackcurrant anthocyanins (BCA), which may be associated with IGF-1 function. We evaluated the changes of cGP and IGF-1 before and after the supplementation. METHODS: Plasma and cerebrospinal fluid (CSF) were collected from 11 male patients before and after 28 day supplementation of BCA. The concentrations of IGF-1, IGF binding protein (IGFBP)-3, and cGP were measured using ELISA and HPLC-MS assays. The presence of cGP in the BCA was evaluated. RESULTS: cGP presented in the BCA. BCA supplementation increased the concentration of cGP (p < 0.01), but not IGF-1 and IGFBP-3 in the CSF. CSF concentration of cGP was correlated with plasma concentration of cGP (R = 0.68, p = 0.01) and cGP/IGF-1 molar ratio (R = 0.66, p = 0.01). The CSF/plasma ratio was high in cGP and low in IGF-1 and IGFBP-3. CONCLUSION: cGP is a natural nutrient to the BCA. The increased CSF cGP in Parkinson disease patients may result from the central uptake of plasma cGP. Given neurotrophic function, oral availability, and effective central uptake of cGP, the BCA has the potential to be developed to treat neurological conditions with IGF-1 deficiency.

In Vitro and In Vivo Study of the Gastrointestinal Absorption and Metabolisation of Hymenocardine, a Cyclopeptide Alkaloid.

Hymenocardine is a cyclopeptide alkaloid present in the root bark of Hymenocardia acida. In traditional African medicine, the leaves and roots of this plant are used to treat malaria, and moderate in vitro antiplasmodial activity has been reported for hymenocardine. However, in view of its peptide-like nature, potential metabolisation after oral ingestion has to be taken into account when considering in vivo experiments. In this study, the stability and small intestinal absorption of hymenocardine was assessed using an in vitro gastrointestinal dialysis model. In addition, potential liver metabolisation was investigated in vitro by incubation with a human S9 fraction. Moreover, hymenocardine was administered to rats per os, and blood and urine samples were collected until 48 and 24 h after oral administration, respectively. All samples resulting from these three experiments were analyzed by LC-MS. Analysis of the dialysate and retentate, obtained from the gastrointestinal dialysis model, indicated that hymenocardine is absorbed unchanged from the gastrointestinal tract, at least in part. After S9 metabolisation, several metabolites of hymenocardine could be identified, the major ones being formed by the reduction and/or the loss of an N-methyl group. The in vivo study confirmed that hymenocardine is absorbed from the gastrointestinal tract unchanged, since it could be identified in both rat plasma and urine, together with hymenocardinol, its reduction product.

Alcohol Consumption-Related Metabolites in Relation to Colorectal Cancer and Adenoma: Two Case-Control Studies Using Serum Biomarkers.

Alcohol is a known carcinogen that may be associated with colorectal cancer. However, most epidemiologic studies assess alcoholic beverage consumption using self-reported data, leading to potential exposure misclassification. Biomarkers of alcohol consumption may provide an alternative, complementary approach that reduces misclassification and incorporates individual differences in alcohol metabolism. Therefore, we evaluated the relationship between previously identified alcohol consumption-related metabolites and colorectal cancer and adenoma using serum metabolomics data from two studies. Data on colorectal cancer were obtained from a nested case-control study of 502 US adults (252 cases, 250 controls) within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Data on colorectal adenoma were obtained from a case-control study of 197 US adults (120 cases, 77 controls) from the Navy Colon Adenoma Study. Unconditional multivariable logistic regression models were fit to calculate odds ratios (OR) and 95% confidence intervals (CI) for eight alcohol consumption-related metabolites identified in a previous analysis: ethyl glucuronide; 4-androstene-3beta,17beta-diol disulfate 1; 5-alpha-androstan-3beta,17beta-diol disulfate; 16-hydroxypalmitate; bilirubin (E,Z or Z,E); cyclo (-leu-pro); dihomo-linoleate (20:2n6); and palmitoleate (16:1n7). We found no clear association between these alcohol consumption-related metabolites and either endpoint. However, we did observe an inverse association between cyclo (-leu-pro) and colorectal adenoma that was only observed in the highest metabolite quantile (OR 4th vs. 1st Quantile = 0.30, 95% CI: 0.12-0.78; P-trend = 0.047), but no association for colorectal cancer. In conclusion, there were no adverse associations between alcohol consumption-related metabolites and colorectal cancer or adenoma.

Lower omega-3 fatty acids are associated with the presence of anti-cyclic citrullinated peptide autoantibodies in a population at risk for future rheumatoid arthritis: a nested case-control study.

OBJECTIVE: The aim of this study was to investigate omega-3 fatty acid (FA) supplement use and omega-3 FAs in erythrocyte membranes [omega-3 FA % in erythrocyte membranes (RBC)] and their association with anti-CCP autoantibodies in a population without RA, but who are at genetic risk for RA. METHODS: The multicentre Studies of the Etiology of RA (SERA) cohort includes RA-free subjects who are first-degree relatives of RA probands or are enriched with the HLA-DR4 allele. In a nested case-control study, 30 SERA cases were identified who were anti-CCP2 antibody positive. We further identified 47 autoantibody negative controls, frequency matched to cases on age at study visit, sex, race and study site. Anti-CCP2 status, self-reported omega-3 FA supplement use and omega-3 FA % in RBCs were obtained from a single visit. RESULTS: Anti-CCP2 positive cases were less likely than controls to report omega-3 FA supplement use (odds ratio: 0.14; 95% CI 0.03, 0.68). In addition, the likelihood of anti-CCP2 positivity was inversely associated with total omega-3 FA % in RBCs (odds ratio: 0.47; 95% CI 0.24, 0.92, for a s.d. increase). CONCLUSION: The inverse association between anti-CCP2 positivity and self-reported omega-3 FA supplement use and omega-3 FA % in RBCs suggests that omega-3 FAs may protect against the development of RA-related autoimmunity in pre-clinical RA.

Efficacy of syringomycin E in a murine model of vaginal candidiasis.

Syringomycin E (SR-E), a new antifungal produced by the bacterium Pseudomonas syringae pv. syringae, was evaluated in a murine vaginal candidiasis model. In one study, mice were treated intravaginally b.i.d. for 4 days with drug carrier, SR-E 2% in either PEG-400 or PEG-ointment, or 1% clotrimazole as a positive control. Quantitative vaginal cultures were taken prior to treatment on day 1 and on days 5, 6, and 7. Both formulations showed a reduction of yeast colonization in the vaginas on day 5 (P< or =0.06 and P< or =0.03 for SR-E/PEG-400 and SR-E/PEG ointment, respectively) and SR-E/PEG ointment reduced the colonization on day 7 (P< or =0.06) when compared to carrier treated controls. In a second study, SR-E was formulated in Aquaphor at three higher concentrations of SR-E [3%, 6%, or 12% (w/v)]. SR-E showed dose-dependent efficacy. The 3% dose showed no effect while the 6% and 12% doses reduced the number of yeasts. The 12% dose showed a significant reduction on days 5 (P< or =0.01), 6 (P< or =0.06), and 7 (P< or =0.03) when compared with the drug carrier controls and on day 5 was more effective than clotrimazole (P< or =0.03). Clotrimazole did not significantly reduce the yeasts in the vagina until days 6 (P< or =0.01) and 7 (P< or =0.01) when compared to the drug carrier controls. No vaginal inflammatory response was evident by histological examination in uninfected animals treated with SR-E. No SR-E could be detected in plasma, kidney, or liver. SR-E (12%) was an effective treatment when compared to 1% clotrimazole.

Novel somatostatin analogs for the treatment of acromegaly and cancer exhibit improved in vivo stability and distribution.

The biodistribution of several radiolabeled somatostatin (SRIF) analogs was determined in the rat. Newly developed analogs BIM-23190 and BIM-23197 attained higher plasma levels and much greater target tissue concentrations than the clinically used BIM-23014 analog. Highest tissue concentrations of BIM-23190 and BIM-23197 were found in adrenal, kidney, pituitary and pancreas, tissues that are known to be abundant in mRNA for the somatostatin subtype 2 receptor. BIM-23190 and BIM-23197 associated radioactivity in these tissues was prolonged compared with that of BIM-23014, especially in the SRIF-receptor-rich pituitary. BIM-23190 and BIM-23197 were more stable in vivo and much less subject to biliary excretion than BIM-23014. These properties account for the elevated plasma and target tissue concentrations of these new SRIF analogs. Based on higher plasma levels, greater distribution to target tissues and longer in vivo stability, BIM-23190 and BIM-23197 may prove to be superior to BIM-23014 for the treatment of acromegaly and some types of cancer.

The effect of DHEA given chronically to Zucker rats.

Dehydroepiandrosterone (DHEA) has been reported to exert antiglucocorticoid activity. When administered to obese, hypercorticosteronemic Zucker rats, it causes a diminution of food intake and a reduction in their rate of weight gain. This experiment was conducted to evaluate whether this biologic effect could be ascribed to chronic adrenal insufficiency. Obese and lean Zucker rats were treated with DHEA as a food supplement for 28 days. Upon sacrifice, organ weights and serum chemistries were measured, along with neurotransmitter levels in regions of the hypothalamus. Results showed that although the obese animals gained weight more slowly, had lower insulin levels, and ate less, their serum glucose, corticosterone, and ACTH levels were not different from control. Hypothalamic neurotransmitters in the obese rat were unaffected by chronic DHEA treatment. We concluded that, although DHEA clearly affects Zucker weight gain, it does not induce chronic adrenal insufficiency.

On the mechanism of fasting-associated elevations in hypothalamic cyclo(His-Pro) content.

Potential mechanism(s) underlying the fasting-associated rise in hypothalamic cyclo(His-Pro) content was explored by examining the effects of 24-hour fasting on: (i) cyclo(His-Pro) synthesis from TRH, (ii) cyclo(His-Pro) metabolism, and (iii) cyclo (His-Pro) secretion by hypothalamic tissue in vitro. The data presented here show that none of these three variables were altered due to fasting. Two additional potential changes that could cause cyclo(His-Pro) elevations during fasting are suggested. These include an in vivo decrease in hypothalamic cyclo(His-Pro) secretion that may not be apparent in vitro, and/or an increase in the synthesis of cyclo(His-Pro) from a precursor(s) other than TRH.