Designed multifunctional polymeric nanomedicines: long-term biodistribution and tumour accumulation of aptamer-targeted nanomaterials

2018 ◽  
Vol 54 (82) ◽  
pp. 11538-11541 ◽  
Author(s):  
N. L. Fletcher ◽  
Z. H. Houston ◽  
J. D. Simpson ◽  
R. N. Veedu ◽  
K. J. Thurecht
Keyword(s):  
Polyethylene Glycol ◽  
Pet Imaging ◽  
Hyperbranched Polymer ◽  
Ex Vivo

We report a novel multifunctional hyperbranched polymer based on polyethylene glycol (PEG) as a nanomedicine platform that facilitates longitudinal and quantitative 89Zr-PET imaging, enhancing knowledge of nanomaterial biodistribution and pharmacokinetics/pharmacodynamics both in vivo and ex vivo.

Strategies to Protect Hematopoietic Stem Cells from Culture-Induced Stress Conditions

2020 ◽  
Vol 15 ◽  
Author(s):  
Fatima Aerts-Kaya
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Ex Vivo ◽  
Stress Conditions ◽  
Stress Factors ◽  
Hematopoietic Stem ◽  
Induced Stress

: In contrast to their almost unlimited potential for expansion in vivo and despite years of dedicated research and optimization of expansion protocols, the expansion of Hematopoietic Stem Cells (HSCs) in vitro remains remarkably limited. Increased understanding of the mechanisms that are involved in maintenance, expansion and differentiation of HSCs will enable the development of better protocols for expansion of HSCs. This will allow procurement of HSCs with long-term engraftment potential and a better understanding of the effects of the external influences in and on the hematopoietic niche that may affect HSC function. During collection and culture of HSCs, the cells are exposed to suboptimal conditions that may induce different levels of stress and ultimately affect their self-renewal, differentiation and long-term engraftment potential. Some of these stress factors include normoxia, oxidative stress, extra-physiologic oxygen shock/stress (EPHOSS), endoplasmic reticulum (ER) stress, replicative stress, and stress related to DNA damage. Coping with these stress factors may help reduce the negative effects of cell culture on HSC potential, provide a better understanding of the true impact of certain treatments in the absence of confounding stress factors. This may facilitate the development of better ex vivo expansion protocols of HSCs with long-term engraftment potential without induction of stem cell exhaustion by cellular senescence or loss of cell viability. This review summarizes some of available strategies that may be used to protect HSCs from culture-induced stress conditions.

scholarly journals Aη-α and Aη-β peptides impair LTP ex vivo within the low nanomolar range and impact neuronal activity in vivo

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Maria Mensch ◽  
Jade Dunot ◽  
Sandy M. Yishan ◽  
Samuel S. Harris ◽  
Aline Blistein ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Ex Vivo ◽  
Long Term Potentiation ◽  
Network Activity ◽  
Strongly Correlated ◽  
App Processing ◽  
Term Potentiation ◽  
Hippocampal Network

Abstract Background Amyloid precursor protein (APP) processing is central to Alzheimer’s disease (AD) etiology. As early cognitive alterations in AD are strongly correlated to abnormal information processing due to increasing synaptic impairment, it is crucial to characterize how peptides generated through APP cleavage modulate synapse function. We previously described a novel APP processing pathway producing η-secretase-derived peptides (Aη) and revealed that Aη–α, the longest form of Aη produced by η-secretase and α-secretase cleavage, impaired hippocampal long-term potentiation (LTP) ex vivo and neuronal activity in vivo. Methods With the intention of going beyond this initial observation, we performed a comprehensive analysis to further characterize the effects of both Aη-α and the shorter Aη-β peptide on hippocampus function using ex vivo field electrophysiology, in vivo multiphoton calcium imaging, and in vivo electrophysiology. Results We demonstrate that both synthetic peptides acutely impair LTP at low nanomolar concentrations ex vivo and reveal the N-terminus to be a primary site of activity. We further show that Aη-β, like Aη–α, inhibits neuronal activity in vivo and provide confirmation of LTP impairment by Aη–α in vivo. Conclusions These results provide novel insights into the functional role of the recently discovered η-secretase-derived products and suggest that Aη peptides represent important, pathophysiologically relevant, modulators of hippocampal network activity, with profound implications for APP-targeting therapeutic strategies in AD.

scholarly journals Assessment of Electrospun Pellethane-Based Scaffolds for Vascular Tissue Engineering

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3678
Author(s):  
Vera Chernonosova ◽  
Alexandr Gostev ◽  
Ivan Murashov ◽  
Boris Chelobanov ◽  
Andrey Karpenko ◽  
...  
Keyword(s):  
Vascular Tissue ◽  
Ex Vivo ◽  
Vascular Grafts ◽  
Wistar Rat ◽  
Graft Occlusion ◽  
Suitable Candidate ◽  
Large Animals ◽  
Cell Adhesion And Proliferation

We examined the physicochemical properties and the biocompatibility and hemocompatibility of electrospun 3D matrices produced using polyurethane Pellethane 2363-80A (Pel-80A) blends Pel-80A with gelatin or/and bivalirudin. Two layers of vascular grafts of 1.8 mm in diameter were manufactured and studied for hemocompatibility ex vivo and functioning in the infrarenal position of Wistar rat abdominal aorta in vivo (n = 18). Expanded polytetrafluoroethylene (ePTFE) vascular grafts of similar diameter were implanted as a control (n = 18). Scaffolds produced from Pel-80A with Gel showed high stiffness with a long proportional limit and limited influence of wetting on mechanical characteristics. The electrospun matrices with gelatin have moderate capacity to support cell adhesion and proliferation (~30–47%), whereas vascular grafts with bivalirudin in the inner layer have good hemocompatibility ex vivo. The introduction of bivalirudin into grafts inhibited platelet adhesion and does not lead to a change hemolysis and D-dimers concentration. Study in vivo indicates the advantages of Pel-80A grafts over ePTFE in terms of graft occlusion, calcification level, and blood velocity after 6 months of implantation. The thickness of neointima in Pel-80A–based grafts stabilizes after three months (41.84 ± 20.21 µm) and does not increase until six months, demonstrating potential for long-term functioning without stenosis and as a suitable candidate for subsequent preclinical studies in large animals.

BioMEMS Technologies for Regenerative Medicine

2008 ◽  
Vol 1139 ◽  
Author(s):  
Jeffrey T. Borenstein
Keyword(s):  
Drug Delivery ◽  
Regenerative Medicine ◽  
Drug Delivery Systems ◽  
Ex Vivo ◽  
Delivery Systems ◽  
Organ Shortage ◽  
Engineered Tissues ◽  
Drug Concentrations

AbstractThe emergence of BioMEMS fabrication technologies such as soft lithography, micromolding and assembly of 3D structures, and biodegradable microfluidics, are already making significant contributions to the field of regenerative medicine. Over the past decade, BioMEMS have evolved from early silicon laboratory devices to polymer-based structures and even biodegradable constructs suitable for a range of ex vivo and in vivo applications. These systems are still in the early stages of development, but the long-term potential of the technology promises to enable breakthroughs in health care challenges ranging from the systemic toxicity of drugs to the organ shortage. Ex vivo systems for organ assist applications are emerging for the liver, kidney and lung, and the precision and scalability of BioMEMS fabrication techniques offer the promise of dramatic improvements in device performance and patient outcomes.Ultimately, the greatest benefit from BioMEMS technologies will be realized in applications for implantable devices and systems. Principal advantages include the extreme levels of achievable miniaturization, integration of multiple functions such as delivery, sensing and closed loop control, and the ability of precision microscale and nanoscale features to reproduce the cellular microenvironment to sustain long-term functionality of engineered tissues. Drug delivery systems based on BioMEMS technologies are enabling local, programmable control over drug concentrations and pharmacokinetics for a broad spectrum of conditions and target organs. BioMEMS fabrication methods are also being applied to the development of engineered tissues for applications such as wound healing, microvascular networks and bioartificial organs. Here we review recent progress in BioMEMS-based drug delivery systems, engineered tissue constructs and organ assist devices for a range of ex vivo and in vivo applications in regenerative medicine.

scholarly journals Acute (24 h) activation of peroxisome proliferator-activated receptor-alpha (PPARalpha) reverses high-fat feeding-induced insulin hypersecretion in vivo and in perifused pancreatic islets

2003 ◽  
Vol 177 (2) ◽  
pp. 197-205 ◽  
Author(s):  
MJ Holness ◽  
ND Smith ◽  
GK Greenwood ◽  
MC Sugden
Keyword(s):  
Insulin Secretion ◽  
Ex Vivo ◽  
Peroxisome Proliferator ◽  
High Fat ◽  
Intravenous Glucose ◽  
Perifused Islets ◽  
Glucose Stimulated Insulin Secretion ◽  
Fat Feeding

Abnormal depletion or accumulation of islet lipid may be important for the development of pancreatic beta cell failure. Long-term lipid sensing by beta cells may be co-ordinated via peroxisome proliferator-activated receptors (PPARs). We investigated whether PPARalpha activation in vivo for 24 h affects basal and glucose-stimulated insulin secretion in vivo after intravenous glucose administration and ex vivo in isolated perifused islets. Insulin secretion after intravenous glucose challenge was greatly increased by high-fat feeding (4 weeks) but glucose tolerance was minimally perturbed, demonstrating insulin hypersecretion compensated for insulin resistance. The effect of high-fat feeding to enhance glucose-stimulated insulin secretion was retained in perifused islets demonstrating a stable, long-term effect of high-fat feeding to potentiate islet glucose stimulus-secretion coupling. Treatment of high-fat-fed rats with WY14,643 for 24 h reversed insulin hypersecretion in vivo without impairing glucose tolerance, suggesting improved insulin action, and ex vivo in perfused islets. PPARalpha activation only affected hypersecretion of insulin since glucose-stimulated insulin secretion was unaffected by WY14,643 treatment in vivo in control rats or in perifused islets from control rats. Our data demonstrate that activation of PPARalpha for 24 h can oppose insulin hypersecretion elicited by high-fat feeding via stable long-term effects exerted on islet function. PPARalpha could, therefore, participate in ameliorating abnormal glucose homeostasis and hyperinsulinaemia in dietary insulin resistance via modulation of islet function, extending the established requirement for PPARalpha for normal islet lipid homeostasis.

Anti-nociceptive and anti-inflammatory activity of synthesized novel benzoxazole derivatives

2021 ◽  
Vol 20 ◽  
Author(s):  
Mansi L. Patil ◽  
Swati S. Gaikwad ◽  
Naresh J. Gaikwad
Keyword(s):  
Cytotoxic Activity ◽  
Research Study ◽  
Ex Vivo ◽  
Immunological Response ◽  
Inflammatory Activity ◽  
Inflammatory Drugs ◽  
Anti Inflammatory ◽  
Inflammatory Effect

Introduction: Pain is an immunological response to any infection or inflammation and long term use of pain management therapy includes use of Nonsteroidal anti-inflammatory drugs which is associated with occurrence of toxicity as well as gastrointestinal bleeding. Therefore, the investigation of new analgesic and anti-inflammatory agents remains a major challenge. Aims: The objective of this research study is to undergo the pharmacological evaluation of newly synthesized benzoxazole derivatives. These novel derivatives were evaluated for anti-nociceptive, anti-inflammatory and cytotoxic activity using various in-vivo and ex-vivo methods. Methods: The study was carried out using swiss mice (adult male) weighing between 20gm to 30gm and were divided into groups containing (n=6) six animals in each group for treatment. The anti-nociceptive activity was performed by using 0.1ml of 0.6% v/v acetic acid as nociception inducer and evaluated by the diminished number of abdominal writhes. The anti-inflammatory activity was done using 0.1 ml of 2% w/v Carrageenan induced paw edema method was observed which was evaluated by calculating the percent maximum possible effect. Histopathological evaluation and cytotoxic activity of the compounds was carried out. Results: The results of this research study revealed that synthesized derivatives (a, b, c, d and e) showed promising anti-nociceptive and anti-inflammatory effect along significantly higher cytotoxic activity in MCF-7 cell lines. Conclusion: It can be concluded that synthesized derivatives (a, b, c, d and e) have potential anti-nociceptive and anti-inflammatory effect along with cytotoxic activity and certain modification in structure may result in potent activity.

Abstract 2876: Early Retention and Subsequent Engraftment of Transplanted Progenitor Cells is Improved by Delivery within Collagen Matrix

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Yan Zhang ◽  
Marc Lamoureux ◽  
Stephanie Thorn ◽  
Vincent Chan ◽  
Joel Price ◽  
...  
Keyword(s):  
Cell Therapy ◽  
Progenitor Cells ◽  
Pet Imaging ◽  
Ex Vivo ◽  
Collagen Matrix ◽  
Cell Labeling ◽  
Type I ◽  
The Matrix ◽  
Early Retention

Background: To investigate the mechanisms involved in the potentiation of cell therapy by delivery matrices, we evaluated the retention and engraftment of transplanted human circulating progenitor cells (CPCs) injected in a collagen matrix by using in vivo positron emission tomography (PET) imaging, ex vivo biodistribution, and immunohistochemistry. Methods: CPCs were labeled with 18 F-FDG and injected with or without a collagen type I-based matrix in the ischemic hindlimb muscle (IM) of rats (2x10 6 cells; n=15/group). Localization of cells was acquired by PET imaging (15 min) at 150 min post-injection. In addition, radionuclide biodistribution, immunofluorescence, and immunohistochemical examination of transplanted CPCs were performed at up to 14 days. Results: Cell labeling efficiency was CPC-concentration dependent (r=0.61, p <0.001), but not 18 F-FDG-dose dependent. Labeled CPCs exhibited excellent short-term stability and viability. Persistence of 18 F-FDG radioactivity in cells was markedly greater than non-specific retention in the matrix. Wholebody (WB) PET images revealed better CPC retention in the IM and less non-specific leakage to other tissues when CPCs were delivered within the matrix (IM/WB retention ratio of 43.9±8.2%), compared to cells injected alone (22.3±10.4%; p =0.040) and to 18 F-FDG injected with or without the matrix (9.7±5.5% and 11.0±5.5%, respectively; p <0.005). Radioactivity biodistribution confirmed that accumulation was increased (by 92.5%; p =0.024) in the IM and reduced (by 1.1 to 23.8%; p <0.05) in non-specific tissues when cells were injected within the matrix, compared to cells injected alone. Anti-human mitochondria staining showed increased cell retention in the IM with use of matrices (3.0±2.1%) versus cells only (1.9±0.8%; p =0.048). At 14 days the number of CD31 + transplanted human cells was greater (1.6±0.1%) when injected within the matrix than injected alone (0.7±0.1%; p =0.004). Conclusions: Collagen-based delivery matrices improve the early retention of transplanted CPCs, which in turn favors subsequent cell engraftment in the ischemic tissue. This mechanism conferred by the matrix has potential implications for the optimization of cell therapy at the early stages after cell delivery.

scholarly journals Quantitative PET imaging of PD-L1 expression in xenograft and syngeneic tumour models using a site-specifically labelled PD-L1 antibody

2019 ◽  
Vol 47 (5) ◽  
pp. 1302-1313 ◽  
Author(s):  
Camilla Christensen ◽  
Lotte K. Kristensen ◽  
Maria Z. Alfsen ◽  
Carsten H. Nielsen ◽  
Andreas Kjaer
Keyword(s):  
Pet Imaging ◽  
Predictive Value ◽  
Ex Vivo ◽  
Response To Therapy ◽  
Whole Body ◽  
Therapeutic Monitoring ◽  
Non Invasive ◽  
Tumour Bearing ◽  
Quantitative Pet

Abstract Purpose Despite remarkable clinical responses and prolonged survival across several cancers, not all patients benefit from PD-1/PD-L1 immune checkpoint blockade. Accordingly, assessment of tumour PD-L1 expression by immunohistochemistry (IHC) is increasingly applied to guide patient selection, therapeutic monitoring, and improve overall response rates. However, tissue-based methods are invasive and prone to sampling error. We therefore developed a PET radiotracer to specifically detect PD-L1 expression in a non-invasive manner, which could be of diagnostic and predictive value. Methods Anti-PD-L1 (clone 6E11, Genentech) was site-specifically conjugated with DIBO-DFO and radiolabelled with 89Zr (89Zr-DFO-6E11). 89Zr-DFO-6E11 was optimized in vivo by longitudinal PET imaging and dose escalation with excess unlabelled 6E11 in HCC827 tumour-bearing mice. Specificity of 89Zr-DFO-6E11 was evaluated in NSCLC xenografts and syngeneic tumour models with different levels of PD-L1 expression. In vivo imaging data was supported by ex vivo biodistribution, flow cytometry, and IHC. To evaluate the predictive value of 89Zr-DFO-6E11 PET imaging, CT26 tumour-bearing mice were subjected to external radiation therapy (XRT) in combination with PD-L1 blockade. Results 89Zr-DFO-6E11 was successfully labelled with a high radiochemical purity. The HCC827 tumours and lymphoid tissue were identified by 89Zr-DFO-6E11 PET imaging, and co-injection with 6E11 increased the relative tumour uptake and decreased the splenic uptake. 89Zr-DFO-6E11 detected the differences in PD-L1 expression among tumour models as evaluated by ex vivo methods. 89Zr-DFO-6E11 quantified the increase in PD-L1 expression in tumours and spleens of irradiated mice. XRT and anti-PD-L1 therapy effectively inhibited tumour growth in CT26 tumour-bearing mice (p < 0.01), and the maximum 89Zr-DFO-6E11 tumour-to-muscle ratio correlated with response to therapy (p = 0.0252). Conclusion PET imaging with 89Zr-DFO-6E11 is an attractive approach for specific, non-invasive, whole-body visualization of PD-L1 expression. PD-L1 expression can be modulated by radiotherapy regimens and 89Zr-DFO-6E11 PET is able to monitor these changes and predict the response to therapy in an immunocompetent tumour model.

Ex Vivo Expansion of Genetically Marked Rhesus Peripheral Blood Progenitor Cells Results in Diminished Long-Term Repopulating Ability

Blood ◽  
1998 ◽  
Vol 92 (4) ◽  
pp. 1131-1141 ◽  
Author(s):  
J.F. Tisdale ◽  
Y. Hanazono ◽  
S.E. Sellers ◽  
B.A. Agricola ◽  
M.E. Metzger ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Ex Vivo ◽  
Retroviral Vectors ◽  
Ex Vivo Expansion ◽  
Us Government ◽  
Government Work ◽  
Stromal Support ◽  
Short And Long Term

Abstract The possibility of primitive hematopoietic cell ex vivo expansion is of interest for both gene therapy and transplantation applications. The engraftment of autologous rhesus peripheral blood (PB) progenitors expanded 10 to 14 days were tracked in vivo using genetic marking. Stem cell factor (SCF)/granulocyte colony-stimulating factor (G-CSF)–mobilized and CD34-enriched PB cells were divided into two equal aliquots and transduced with one of two retroviral vectors carrying the neomycin-resistance gene (neo) for 4 days in the presence of interleukin-3 (IL-3), IL-6, and SCF in the first 5 animals, IL-3/IL-6/SCF/Flt-3 ligand (FLT) in 2 subsequent animals, or IL-3/IL-6/SCF/FLT plus an autologous stromal monolayer (STR) in the final 2. At the end of transduction period, one aliquot (nonexpanded) from each animal was frozen, whereas the other was expanded under the same conditions but without vector for a total of 14 days before freezing. After total body irradiation, both the nonexpanded and expanded transduced cells were reinfused. Despite 5- to 13-fold higher cell and colony-forming unit (CFU) doses from the expanded fraction of marked cells, there was greater short- and long-term marking from the nonexpanded cells in all animals. In animals receiving cells transduced and expanded in the presence of IL-3/IL-6/SCF/FLT, engraftment by the marked expanded cells was further diminished. This discrepancy was even more pronounced in the animals who received cells transduced and expanded in the presence of FLT and autologous stroma, with no marking detectable from the expanded cells. Despite lack of evidence for expansion of engrafting cells, we found that the addition of FLT and especially STR during the initial brief transduction period increased engraftment with marked cells into a clinically relevant range. Levels of marked progeny cells originating from the nonexpanded aliqouts were significantly higher than that seen in previous 4 animals receiving cells transduced in the presence of IL-3/IL-6/SCF, with levels of 10% to 20% confirmed by Southern blotting from the nonexpanded IL-3/IL-6/SCF/FLT/STR graft compared with 0.01% in the original IL-3/IL-6/SCF cohort. These results suggest that, although expansion of PB progenitors is feasible ex vivo, their contribution towards both short- and long-term engraftment is markedly impaired. However, a brief transduction in the presence of specific cytokines and stromal support allows engraftment with an encouraging number of retrovirally modified cells. This is a US government work. There are no restrictions on its use.

scholarly journals Development and long-term evaluation of a new 68Ge/68Ga generator based on nano-SnO2 for PET imaging

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Eduardo Romero ◽  
Alfonso Martínez ◽  
Marta Oteo ◽  
Marta Ibañez ◽  
Mirentxu Santos ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Mouse Model ◽  
Pet Imaging ◽  
Research Reactor ◽  
On Demand ◽  
Term Evaluation ◽  
Investigation Period ◽  
Direct Use

AbstractRadionuclide generator systems can routinely provide radionuclides on demand such as 68Ga produced by a 68Ge/68Ga generator without the availability of an on-site accelerator or a research reactor. Thus, in this work nano-SnO2 was used to develop a new 68Ge/68Ga generator which was evaluated over a period of 17 months and 305 elution cycles. The elution yield was 91.1 ± 1.8% in the first 7 mL (1 M HCl as eluent) when the generator was new and then it decreased with time and use to 73.8 ± 1.9%. Around 80% of the elutable 68Ga activity was obtained in 1 mL and the 68Ge content in the eluate did not exceed 1 × 10–4% over the investigation period when it was eluted regularly. The described generator provided adequate results for radiolabelling of DOTA-TOC with direct use of eluate. In addition, [68Ga]Ga-DOTA-TOC was tested satisfactorily for in vivo tumor detection by microPET/CT imaging in a lung cancer mouse model.

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