Beta-Carotene Reduces Body Adiposity of Mice via BCMO1

Evidence from cell culture studies indicates that β-carotene-(BC)-derived apocarotenoid signaling molecules can modulate the activities of nuclear receptors that regulate many aspects of adipocyte physiology. Two BC metabolizing enzymes, the BC-15,15′-oxygenase (Bcmo1) and the BC-9′,10′-oxygenase (Bcdo2) are expressed in adipocytes. Bcmo1 catalyzes the conversion of BC into retinaldehyde and Bcdo2 into β-10′-apocarotenal and β-ionone. Here we analyzed the impact of BC on body adiposity of mice. To genetically dissect the roles of Bcmo1 and Bcdo2 in this process, we used wild-type and Bcmo1-/- mice for this study. In wild-type mice, BC was converted into retinoids. In contrast, Bcmo1-/- mice showed increased expression of Bcdo2 in adipocytes and β-10′-apocarotenol accumulated as the major BC derivative. In wild-type mice, BC significantly reduced body adiposity (by 28%), leptinemia and adipocyte size. Genome wide microarray analysis of inguinal white adipose tissue revealed a generalized decrease of mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ) target genes. Consistently, the expression of this key transcription factor for lipogenesis was significantly reduced both on the mRNA and protein levels. Despite β-10′-apocarotenoid production, this effect of BC was absent in Bcmo1-/- mice, demonstrating that it was dependent on the Bcmo1-mediated production of retinoids. Our study evidences an important role of BC for the control of body adiposity in mice and identifies Bcmo1 as critical molecular player for the regulation of PPARγ activity in adipocyte

Knockout of the Bcmo1 gene results in an inflammatory response in female lung, which is suppressed by dietary beta-carotene

Beta-carotene 15,15′-monooxygenase 1 knockout (Bcmo1−/−) mice accumulate beta-carotene (BC) similarly to humans, whereas wild-type (Bcmo1+/+) mice efficiently cleave BC. Bcmo1−/− mice are therefore suitable to investigate BC-induced alterations in gene expression in lung, assessed by microarray analysis. Bcmo1−/− mice receiving control diet had increased expression of inflammatory genes as compared to BC-supplemented Bcmo1−/− mice and Bcmo1+/+ mice that received either control or BC-supplemented diets. Differential gene expression in Bcmo1−/− mice was confirmed by real-time quantitative PCR. Histochemical analysis indeed showed an increase in inflammatory cells in lungs of control Bcmo1−/− mice. Supported by metabolite and gene-expression data, we hypothesize that the increased inflammatory response is due to an altered BC metabolism, resulting in an increased vitamin A requirement in Bcmo1−/− mice. This suggests that effects of BC may depend on inter-individual variations in BC-metabolizing enzymes, such as the frequently occurring human polymorphisms in BCMO1

Age dating of an early Milky Way merger via asteroseismology of the naked-eye star ν Indi

Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies1. Although these accreted stellar populations can be forensically identified as kinematically distinct structures within the Galaxy, it is difficult in general to date precisely the age at which any one merger occurred. Recent results have revealed a population of stars that were accreted via the collision of a dwarf galaxy, called Gaia–Enceladus1, leading to substantial pollution of the chemical and dynamical properties of the Milky Way. Here we identify the very bright, naked-eye star ν Indi as an indicator of the age of the early in situ population of the Galaxy. We combine asteroseismic, spectroscopic, astrometric and kinematic observations to show that this metal-poor, alpha-element-rich star was an indigenous member of the halo, and we measure its age to be 11.0±0.7 (stat) ±0.8 (sys) billion years. The star bears hallmarks consistent with having been kinematically heated by the Gaia–Enceladus collision. Its age implies that the earliest the merger could have begun was 11.6 and 13.2 billion years ago, at 68% and 95% confidence, respectively. Computations based on hierarchical cosmological models slightly reduce the above limits

In vitro and in vivo evaluation of the bifunctional chelator NODIA-Me in combination with a prostate-specific membrane antigen targeting vector

Introduction We recently developed a chelating platform based on the macrocycle 1,4,7-triazacyclononane with up to three five-membered azaheterocyclic arms for complexation of the PET nuclides gallium-68 and copper-64. The main objective of this study was to evaluate the stability and pharmacokinetics of 68Ga- and 64Cu-complexes of the bifunctional chelator NODIA-Me 1 covalently bound to a PSMA targeting vector in vivo. Methods NODIA-Me 1 was conjugated to the PSMA targeting Glu-NH-CO-NH-Lys moiety to give the bioconjugate NODIA-Me-NaI-Ahx-PSMA 4. The stability of [68Ga]4 and [64Cu]4 was assessed in vitro by serum stability studies. The PSMA binding affinity was determined in competitive cell experiments in LNCaP cells using 68Ga-PSMA-HBED-CC as radioligand. The stability and pharmacokinetics of [68Ga]4 and [64Cu]4 was evaluated by PET imaging and ex vivo biodistribution studies in mice bearing subcutaneous LNCaP tumors. Results In human serum, [68Ga]4 and [64Cu]4 remained intact to 85% (3 h) and 92% (24 h), respectively. Nature of the metal chelate influenced PSMA binding affinity with IC50 of 233 ± 10 nM for uncomplexed 4, 681 ± 7 nM for Cu-4 and 176 ± 10 nM for Ga-4. In animal studies, [68Ga]4 and [64Cu]4 revealed low uptake (≤1% IA g−1) in the majority of organs. Kidney uptake at 1 h p.i. was 6.28 ± 0.92% IA g−1 and 4.96 ± 0.79% IA g−1 and specific tumor uptake was 1.33 ± 0.46% IA g−1 and 2.15 ± 0.38% IA g−1 for [68Ga]4 and [64Cu]4, respectively. Conclusion The bifunctional chelator NODIA-Me 1 was successfully conjugated to a PSMA targeting moiety. In small-animal PET imaging and ex vivo biodistribution studies, 68Ga- and 64Cu-labelled conjugates specifically delineated PSMA-positive LNCaP tumors and exhibited rapid renal clearance from non-target tissues with no significant demetallation/transchelation in vivo. The results support further development of this novel chelating platform for production of 68Ga- and 64Cu-labelled radiopharmaceuticals

Preparation and preclinical evaluation of a 68Ga-labelled c(RGDfK) conjugate comprising the bifunctional chelator NODIA-Me

Abstract Background We recently developed a chelating platform based on the macrocycle 1,4,7-triazacyclononane with up to three, five-membered azaheterocyclic arms for the development of 68Ga- and 64Cu-based radiopharmaceuticals. Here, a 68Ga-labelled conjugate comprising the bifunctional chelator NODIA-Me in combination with the αvß3-targeting peptide c(RGDfK) has been synthesized and characterized. The primary aim was to evaluate further the potential of our NODIA-Me chelating system for the development of 68Ga-labelled radiotracers. Results The BFC NODIA-Me was conjugated to c(RGDfK) by standard peptide chemistry to obtain the final bioconjugate NODIA-Me-c(RGDfK) 3 in 72% yield. Labelling with [68Ga]GaCl3 was accomplished in a fully automated, cGMP compliant process to give [68Ga]3 in high radiochemical yield (98%) and moderate specific activity (~ 8 MBq nmol− 1). Incorporation of the Ga-NODIA-Me chelate to c(RGDfK) 2 had only minimal influence on the affinity to integrin αvß3 (IC50 values [natGa]3 = 205.1 ± 1.4 nM, c(RGDfK) 2 = 159.5 ± 1.3 nM) as determined in competitive cell binding experiments in U-87 MG cell line. In small-animal PET imaging and ex vivo biodistribution studies, the radiotracer [68Ga]3 showed low uptake in non-target organs and specific tumor uptake in U-87 MG tumors. Conclusion The results suggest that the bifunctional chelator NODIA-Me is an interesting alternative to existing ligands for the development of 68Ga-labelled radiopharmaceuticals

In vitro and in vivo evaluation of the bifunctional chelator NODIA-Me in combination with a prostate-specific membrane antigen targeting vector

INTRODUCTION: We recently developed a chelating platform based on the macrocycle 1,4,7-triazacyclononane with up to three five-membered azaheterocyclic arms for complexation of the PET nuclides gallium-68 and copper-64. The main objective of this study was to evaluate the stability and pharmacokinetics of 68Ga- and 64Cu-complexes of the bifunctional chelator NODIA-Me 1 covalently bound to a PSMA targeting vector in vivo. METHODS: NODIA-Me 1 was conjugated to the PSMA targeting Glu-NH-CO-NH-Lys moiety to give the bioconjugate NODIA-Me-NaI-Ahx-PSMA 4. The stability of [68Ga]4 and [64Cu]4 was assessed in vitro by serum stability studies. The PSMA binding affinity was determined in competitive cell experiments in LNCaP cells using 68Ga-PSMA-HBED-CC as radioligand. The stability and pharmacokinetics of [68Ga]4 and [64Cu]4 was evaluated by PET imaging and ex vivo biodistribution studies in mice bearing subcutaneous LNCaP tumors. RESULTS: In human serum, [68Ga]4 and [64Cu]4 remained intact to 85% (3 h) and 92% (24 h), respectively. Nature of the metal chelate influenced PSMA binding affinity with IC50 of 233 ± 10 nM for uncomplexed 4, 681 ± 7 nM for Cu-4 and 176 ± 10 nM for Ga-4. In animal studies, [68Ga]4 and [64Cu]4 revealed low uptake (≤1% IA g-1) in the majority of organs. Kidney uptake at 1 h p.i. was 6.28 ± 0.92% IA g-1 and 4.96 ± 0.79% IA g-1 and specific tumor uptake was 1.33 ± 0.46% IA g-1 and 2.15 ± 0.38% IA g-1 for [68Ga]4 and [64Cu]4, respectively. CONCLUSION: The bifunctional chelator NODIA-Me 1 was successfully conjugated to a PSMA targeting moiety. In small-animal PET imaging and ex vivo biodistribution studies, 68Ga- and 64Cu-labelled conjugates specifically delineated PSMA-positive LNCaP tumors and exhibited rapid renal clearance from non-target tissues with no significant demetallation/transchelation in vivo. The results support further development of this novel chelating platform for production of 68Ga- and 64Cu-labelled radiopharmaceuticals

Assumptions of Mixed Treatment Comparisons in Health Technology Assessments - Challenges and Possible Steps for Practical Application

<div><p>The validity of mixed treatment comparisons (MTCs), also called network meta-analysis, relies on whether it is reasonable to accept the underlying assumptions on similarity, homogeneity, and consistency. The aim of this paper is to propose a practicable approach to addressing the underlying assumptions of MTCs. Using data from clinical studies of antidepressants included in a health technology assessment (HTA), we present a stepwise approach to dealing with challenges related to checking the above assumptions and to judging the robustness of the results of an MTC. At each step, studies that were dissimilar or contributed to substantial heterogeneity or inconsistency were excluded from the primary analysis. In a comparison of the MTC estimates from the consistent network with the MTC estimates from the homogeneous network including inconsistencies, few were affected by notable changes; that is, a change in effect size (factor 2), direction of effect or statistical significance. Considering the small proportion of studies excluded from the network due to inconsistency, as well as the number of notable changes, the MTC results were deemed sufficiently robust. In the absence of standard methods, our approach to checking assumptions in MTCs may inform other researchers in need of practical options, particularly in HTA.</p></div

Change in effect estimates and uncertainty intervals after a stepwise approach to checking homogeneity and consistency assumptions.

<p>Change in effect estimates and uncertainty intervals after a stepwise approach to checking homogeneity and consistency assumptions.</p

Impact of achieving consistency on expected treatment effects within pairs of treatments in the full network.

<p>Impact of achieving consistency on expected treatment effects within pairs of treatments in the full network.</p

Outcome-specific network (treatment discontinuation due to adverse events, acute studies).

<p>Outcome-specific network (treatment discontinuation due to adverse events, acute studies).</p