scholarly journals A revised action spectrum for vitamin D synthesis by suberythemal UV radiation exposure in humans in vivo

2021 ◽  
Vol 118 (40) ◽  
pp. e2015867118
Author(s):  
Antony R. Young ◽  
Kylie A. Morgan ◽  
Graham I. Harrison ◽  
Karl P. Lawrence ◽  
Bibi Petersen ◽  
...  
Keyword(s):  
Vitamin D ◽  
Uv Radiation ◽  
Ex Vivo ◽  
Regression Line ◽  
Action Spectrum ◽  
Blue Shift ◽  
Biologically Active ◽  
Uvb Radiation ◽  
Action Spectra

Action spectra are important biological weighting functions for risk/benefit analyses of ultraviolet (UV) radiation (UVR) exposure. One important human benefit of exposure to terrestrial solar UVB radiation (∼295 to 315 nm) is the cutaneous synthesis of vitamin D3 that is initiated by the photoconversion of 7-dehydrocholesterol to previtamin D3. An action spectrum for this process that is followed by other nonphotochemical steps to achieve biologically active vitamin D3 has been established from ex vivo data and is widely used, although its validity has been questioned. We tested this action spectrum in vivo by full- or partial-body suberythemal irradiation of 75 healthy young volunteers with five different polychromatic UVR spectra on five serial occasions. Serum 25-hydroxyvitamin D3 [25(OH)D3] levels, as the most accurate measure of vitamin D3 status, were assessed before, during, and after the exposures. These were then used to generate linear dose–response curves that were different for each UVR spectrum. It was established that the previtamin D3 action spectrum was not valid when related to the serum 25(OH)D3 levels, as weighting the UVR doses with this action spectrum did not result in a common regression line unless it was adjusted by a blue shift, with 5 nm giving the best fit. Such a blue shift is in accord with the published in vitro action spectra for vitamin D3 synthesis. Thus, calculations regarding the risk (typically erythema) versus the benefit of exposure to solar UVR based on the ex vivo previtamin D3 action spectrum require revision.

scholarly journals Calcitriol and Non-Calcemic Vitamin D Analogue, 22-Oxacalcitriol, Attenuate Developmental and Pathological Ocular Angiogenesis Ex Vivo and In Vivo

2019 ◽  
Author(s):  
SL Merrigan ◽  
B Park ◽  
Z Ali ◽  
LD Jensen ◽  
TW Corson ◽  
...  
Keyword(s):  
Vitamin D ◽  
Ex Vivo ◽  
Active Form ◽  
Biologically Active ◽  
Age Related Macular Degeneration ◽  
Lesion Volume ◽  
Angiogenic Activity ◽  
Ocular Angiogenesis ◽  
Vitamin D Analogue

AbstractAberrant ocular blood vessel growth can underpin vision loss in leading causes of blindness, including neovascular age-related macular degeneration, retinopathy of prematurity and proliferative diabetic retinopathy. Current pharmacological interventions require repeated invasive administrations, lack efficacy in some patients and are associated with poor patient compliance and tachyphylaxis. Small molecule vitamin D has de novo pro-differentiative, anti-proliferative, immunomodulatory, pro-apoptotic and anti-angiogenic properties. Here, our aim was to validate the anti-angiogenic activity of the biologically active form of vitamin D, calcitriol, and a selected vitamin D analogue, 22-oxacalcitriol, across a range of ocular angiogenesis models.First, we validated the anti-angiogenic activity of calcitriol, showing calcitriol to significantly inhibit choroidal sprouting in an ex vivo mouse choroidal fragment sprouting assay. Viability studies in human RPE cell line, ARPE-19, suggested non-calcemic vitamin D analogues have the least off-target anti-proliferative activity compared to calcitriol and additional analogues. Thereafter, the ocular anti-angiogenic activity of non-calcemic vitamin D analogue, 22-oxacalcitriol, was demonstrated in the ex vivo mouse choroidal fragment sprouting assay. In zebrafish larvae, 22-oxacalcitriol was anti-angiogenic, inducing a dose-dependent reduction in choriocapillary angiogenesis. Inhibition of mouse retinal vasculature development was not induced by systemically delivered calcitriol. However, both calcitriol and 22-oxacalcitriol administered intraperitoneally significantly attenuate choroidal neovascularisation lesion volume in the laser-induced CNV mouse model. 22-oxacalcitriol presented with a more favourable safety profile than calcitriol.In summary, calcitriol and 22-oxacalcitriol attenuate ex vivo and in vivo choroidal vasculature angiogenesis. Vitamin D has potential as a preventative or interventional treatment for ophthalmic neovascular indications.

scholarly journals An in-vitro assay using human spermatozoa to detect toxicity of biologically active substances

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tino Vollmer ◽  
Börje Ljungberg ◽  
Vera Jankowski ◽  
Joachim Jankowski ◽  
Griet Glorieux ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Toxicity Testing ◽  
Biologically Active ◽  
Human Spermatozoa ◽  
Vitro Assay ◽  
Cellular Behavior ◽  
Novel Method ◽  
Set Up

Abstract Identifying the key toxic players within an in-vivo toxic syndrome is crucial to develop targeted therapies. Here, we established a novel method that characterizes the effect of single substances by means of an ex-vivo incubation set-up. We found that primary human spermatozoa elicit a distinct motile response on a (uremic) toxic milieu. Specifically, this approach describes the influence of a bulk toxic environment (uremia) as well as single substances (uremic toxins) by real-time analyzing motile cellular behavior. We established the human spermatozoa-based toxicity testing (HSTT) for detecting single substance-induced toxicity to be used as a screening tool to identify in-vivo toxins. Further, we propose an application of the HSTT as a method of clinical use to evaluate toxin-removing interventions (hemodialysis).

scholarly journals Synthesis, CYP24A1-Dependent Metabolism and Antiproliferative Potential against Colorectal Cancer Cells of 1,25-Dihydroxyvitamin D2 Derivatives Modified at the Side Chain and the A-Ring

2020 ◽  
Vol 21 (2) ◽  
pp. 642
Author(s):  
Magdalena Milczarek ◽  
Michał Chodyński ◽  
Anita Pietraszek ◽  
Martyna Stachowicz-Suhs ◽  
Kaori Yasuda ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Vitamin D ◽  
Cancer Cells ◽  
Biologically Active ◽  
Side Chain ◽  
Anticancer Properties ◽  
Colorectal Cancer Cells ◽  
Ht 29

Experimental data indicate that low-calcemic vitamin D derivatives (VDDs) exhibit anticancer properties, both in vitro and in vivo. In our search for a vitamin D analog as potential anticancer agent, we investigated the influence of chirality in the side chain of the derivatives of 1,25-dihydroxyergocalciferol (1,25D2) on their activities. In this study, we synthesized modified analogs at the side chain and the A-ring, which differed from one another in their absolute configuration at C-24, namely (24S)- and (24R)-1,25-dihydroxy-19-nor-20a-homo-ergocalciferols (PRI-5105 and PRI-5106, respectively), and evaluated their activity. Unexpectedly, despite introducing double-point modifications, both analogs served as very good substrates for the vitamin D-hydroxylating enzyme. Irrespective of their absolute C-24 configuration, PRI-5105 and PRI-5106 showed relatively low resistance to CYP24A1-dependent metabolic deactivation. Additionally, both VDDs revealed a similar antiproliferative activity against HT-29 colorectal cancer cells which was higher than that of 1,25D3, the major biologically active metabolite of vitamin D. Furthermore, PRI-5105 and PRI-5106 significantly enhanced the cell growth-inhibitory activity of 5-fluorouracil on HT-29 cell line. In conclusion, although the two derivatives showed a relatively high anticancer potential, they exhibited undesired high metabolic conversion.

scholarly journals Exosome: A New Player in Translational Nanomedicine

2020 ◽  
Vol 9 (8) ◽  
pp. 2380 ◽  
Author(s):  
Houssam Aheget ◽  
María Tristán-Manzano ◽  
Loubna Mazini ◽  
Marina Cortijo-Gutierrez ◽  
Pablo Galindo-Moreno ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Cell Types ◽  
Structural Features ◽  
Biologically Active ◽  
Biological Processes ◽  
New Approach ◽  
Current State ◽  
Exosome Biogenesis ◽  
Production Techniques

Summary: Exosomes are extracellular vesicles released by the vast majority of cell types both in vivo and ex vivo, upon the fusion of multivesicular bodies (MVBs) with the cellular plasma membrane. Two main functions have been attributed to exosomes: their capacity to transport proteins, lipids and nucleic acids between cells and organs, as well as their potential to act as natural intercellular communicators in normal biological processes and in pathologies. From a clinical perspective, the majority of applications use exosomes as biomarkers of disease. A new approach uses exosomes as biologically active carriers to provide a platform for the enhanced delivery of cargo in vivo. One of the major limitations in developing exosome-based therapies is the difficulty of producing sufficient amounts of safe and efficient exosomes. The identification of potential proteins involved in exosome biogenesis is expected to directly cause a deliberate increase in exosome production. In this review, we summarize the current state of knowledge regarding exosomes, with particular emphasis on their structural features, biosynthesis pathways, production techniques and potential clinical applications.

scholarly journals Antioxidant and Anti-inflammatory Effect of Cannabidiol Contributes to the Decreased Lipid Peroxidation of Keratinocytes of Rat Skin Exposed to UV Radiation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Anna Jastrząb ◽  
Iwona Jarocka-Karpowicz ◽  
Agnieszka Markowska ◽  
Adam Wroński ◽  
Agnieszka Gęgotek ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Uv Radiation ◽  
Physical Factor ◽  
Uvb Radiation ◽  
Rat Skin ◽  
Metabolic Disturbances ◽  
Skin Cells ◽  
Anti Inflammatory ◽  
Proinflammatory Factors

There is a great need for compounds with antioxidant and anti-inflammatory properties for protection against UV radiation, which is the most prooxidative physical factor that skin cells are exposed to everyday. Therefore, the aim of the study was to evaluate the mechanism of phytocannabinoid-cannabidiol (CBD) action in vivo on lipid metabolism in keratinocytes of rat skin exposed to UVA/UVB radiation. Our results show that CBD protects keratinocytes against the effects of UVA/UVB radiation by reducing lipid peroxidation products: 4-HNE and 8-isoPGF2α. In addition, CBD significantly increases the level of endocannabinoids, such as anandamide, 2-arachidonylglycerol, and palmitoylethanolamide, and the activation of their receptors CB1/2 or TRPV1. The above changes are due to the protective effect of CBD against the UVA/UVB-induced decrease in the level/activity of superoxide dismutase and the components of the thioredoxin and glutathione systems. CBD also increases the in vivo transcriptional activity of Nrf2 and the expression of its Bach1 inhibitor as well as preventing the UVA/UVB-induced increase in the expression of Nrf2 activators p21, p62, p38, and KAP1 and proinflammatory factors such as NFκB and TNFα. By counteracting oxidative stress and changes in lipid structure in keratinocytes, CBD prevents cellular metabolic disturbances, protecting the epidermis against UV damage.

scholarly journals Calcitriol and non-calcemic vitamin D analogue, 22-oxacalcitriol, attenuate developmental and pathological choroidal vasculature angiogenesis ex vivo and in vivo

Oncotarget ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 493-509 ◽  
Author(s):  
Stephanie L. Merrigan ◽  
Bomina Park ◽  
Zaheer Ali ◽  
Lasse D. Jensen ◽  
Timothy W. Corson ◽  
...  
Keyword(s):  
Vitamin D ◽  
Ex Vivo ◽  
Choroidal Vasculature ◽  
Vitamin D Analogue

scholarly journals Vitamin D Enhances Radiosensitivity of Colorectal Cancer by Reversing Epithelial-Mesenchymal Transition

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinyue Yu ◽  
Qian Wang ◽  
Baocai Liu ◽  
Ning Zhang ◽  
Guanghui Cheng
Keyword(s):  
Colorectal Cancer ◽  
Vitamin D ◽  
Epithelial Mesenchymal Transition ◽  
Active Form ◽  
Plasminogen Activator Inhibitor ◽  
Biologically Active ◽  
Plasminogen Activator Inhibitor 1 ◽  
Mesenchymal Transition

Colorectal cancer (CRC) is often resistant to conventional therapies. Previous studies have reported the anticancer effects of vitamin D in several cancers, its role in radiotherapy (RT) remains unknown. We found that 1α, 25-dihydroxyvitamin D3 (VD3), the biologically active form of vitamin D, had antitumor effect on CRC and sensitized CRC cells to ionizing radiation (IR). VD3 demonstrated synergistic effect in combination with IR, which were detected by colony formation and cell proliferation assay. Radiosensitivity restoration induced by VD3 was associated with a series of phenotypes, including apoptosis, autophagy, and epithelial-mesenchymal transition (EMT). Using proteomics, “regulation of cell migration” and “cadherin” were found to be obviously enriched GO terms. Moreover, cystatin D and plasminogen activator inhibitor-1 (PAI-1), the differentially expressed proteins, were associated with EMT. Next, we confirmed the contributions of these two genes in enhancing IR sensitivity of CRC cells upon inhibition of EMT. As determined by proteomics, the mechanism underlying such sensitivity involved partially block of JAK/STAT3 signaling pathway. Furthermore, VD3 also elicited sensitization to RT in xenograft CRC models without additional toxicity. Our study revealed that VD3 was able to act in synergy with IR both in vitro and in vivo and could also confer radiosensitivity by regulating EMT, thereby providing a novel insight for elevating the efficacy of therapeutic regimens.

scholarly journals A Semi Rigid Novel Hydroxamate AMPED-Based Ligand for 89Zr PET Imaging

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5819
Author(s):  
Lisa Russelli ◽  
Francesco De Rose ◽  
Loredana Leone ◽  
Sybille Reder ◽  
Markus Schwaiger ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Ex Vivo ◽  
Small Animal ◽  
Biologically Active ◽  
Small Animal Pet ◽  
Organ Distribution ◽  
Complexing Agent ◽  
Distribution Studies

In this work, we designed, developed, characterized, and investigated a new chelator and its bifunctional derivative for 89Zr labeling and PET-imaging. In a preliminary study, we synthesized two hexadentate chelators named AAZTHAS and AAZTHAG, based on the seven-membered heterocycle AMPED (6-amino-6-methylperhydro-1,4-diazepine) with the aim to increase the rigidity of the 89Zr complex by using N-methyl-N-(hydroxy)succinamide or N-methyl-N-(hydroxy)glutaramide pendant arms attached to the cyclic structure. N-methylhydroxamate groups are the donor groups chosen to efficiently coordinate 89Zr. After in vitro stability tests, we selected the chelator with longer arms, AAZTHAG, as the best complexing agent for 89Zr presenting a stability of 86.4 ± 5.5% in human serum (HS) for at least 72 h. Small animal PET/CT static scans acquired at different time points (up to 24 h) and ex vivo organ distribution studies were then carried out in healthy nude mice (n = 3) to investigate the stability and biodistribution in vivo of this new 89Zr-based complex. High stability in vivo, with low accumulation of free 89Zr in bones and kidneys, was measured. Furthermore, an activated ester functionalized version of AAZTHAG was synthesized to allow the conjugation with biomolecules such as antibodies. The bifunctional chelator was then conjugated to the human anti-HER2 monoclonal antibody Trastuzumab (Tz) as a proof of principle test of conjugation to biologically active molecules. The final 89Zr labeled compound was characterized via radio-HPLC and SDS-PAGE followed by autoradiography, and its stability in different solutions was assessed for at least 4 days.

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