High Temporal Resolution Detection of Patient-Specific Glucose Uptake from Human ex Vivo Adipose Tissue On-Chip

2015 ◽  
Vol 87 (13) ◽  
pp. 6535-6543 ◽  
Author(s):  
Alessandro Zambon ◽  
Alice Zoso ◽  
Onelia Gagliano ◽  
Enrico Magrofuoco ◽  
Gian Paolo Fadini ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Glucose Uptake ◽  
Temporal Resolution ◽  
Ex Vivo ◽  
Patient Specific ◽  
High Temporal Resolution ◽  
On Chip

scholarly journals Rapid Lipolytic Oscillations in Ex-Vivo Adipose Tissue Explants Revealed Through Microfluidic Droplet Sampling at High Temporal Resolution

2019 ◽  
Author(s):  
Juan Hu ◽  
xiangpeng li ◽  
Robert L. Judd ◽  
Christopher Easley
Keyword(s):  
Adipose Tissue ◽  
High Resolution ◽  
Temporal Resolution ◽  
Ex Vivo ◽  
Analytical Framework ◽  
Tissue Level ◽  
Droplet Microfluidics ◽  
Biological Information ◽  
High Temporal Resolution ◽  
Tissue Explants

Our understanding of adipose tissue biology has steadily evolved. While structural and energy storage functionalities have been in the forefront, a key endocrine role for adipocytes was revealed only over the last few decades. In contrast to the wealth of information on dynamic function of other endocrine tissues, few studies have focused on dynamic adipose tissue function or on tool development toward that end. Here, we apply our unique droplet-based microfluidic devices to culture, perfuse, and sample secretions from primary murine epididymal white adipose tissue (eWAT), and from predifferentiated clusters of 3T3-L1 adipocytes. Through automated control, oil-segmented aqueous droplets (~2.6 nL) were sampled from tissue or cells at 3.5-second temporal resolution, with integrated enzyme assays enabling real-time quantification of glycerol (down to 1.9 fmol droplet<sup>-1</sup>). This high resolution revealed previously unreported oscillations in secreted glycerol at frequencies of 0.2 to 2.0 min<sup>-1</sup> (~30-300 s periods) present in the primary tissue but not in clustered cells. Low-level bursts (~50 fmol) released in basal conditions were contrasted with larger bursts (~300 fmol) during stimulation. Further, both fold changes and burst magnitudes were decreased in eWAT of aged and obese mice. These results, combined with immunostaining and photobleaching analyses, suggest that gap-junctional coupling or nerve cell innervation within the intact ex-vivo tissue explants play important roles in this apparent tissue-level, lipolytic synchronization. High-resolution, quantitative sampling by droplet microfluidics thus permitted unique biological information to be observed, giving an analytical framework poised for future studies of dynamic oscillatory function of adipose and other tissues.

scholarly journals Rapid lipolytic oscillations in ex vivo adipose tissue explants revealed through microfluidic droplet sampling at high temporal resolution

Lab on a Chip ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 1503-1512 ◽  
Author(s):  
Juan Hu ◽  
Xiangpeng Li ◽  
Robert L. Judd ◽  
Christopher J. Easley
Keyword(s):  
Adipose Tissue ◽  
Temporal Resolution ◽  
Ex Vivo ◽  
Microfluidic System ◽  
Quantitative Detection ◽  
High Temporal Resolution ◽  
Tissue Explants ◽  
System P

High temporal resolution sampling and quantitative detection of glycerol secretion dynamics from adipose tissue using our automated, droplet-based microfluidic system.

scholarly journals Rapid Lipolytic Oscillations in Ex-Vivo Adipose Tissue Explants Revealed Through Microfluidic Droplet Sampling at High Temporal Resolution

2019 ◽  
Author(s):  
Juan Hu ◽  
xiangpeng li ◽  
Robert L. Judd ◽  
Christopher Easley
Keyword(s):  
Adipose Tissue ◽  
High Resolution ◽  
Temporal Resolution ◽  
Ex Vivo ◽  
Analytical Framework ◽  
Tissue Level ◽  
Droplet Microfluidics ◽  
Biological Information ◽  
High Temporal Resolution ◽  
Tissue Explants

Our understanding of adipose tissue biology has steadily evolved. While structural and energy storage functionalities have been in the forefront, a key endocrine role for adipocytes was revealed only over the last few decades. In contrast to the wealth of information on dynamic function of other endocrine tissues, few studies have focused on dynamic adipose tissue function or on tool development toward that end. Here, we apply our unique droplet-based microfluidic devices to culture, perfuse, and sample secretions from primary murine epididymal white adipose tissue (eWAT), and from predifferentiated clusters of 3T3-L1 adipocytes. Through automated control, oil-segmented aqueous droplets (~2.6 nL) were sampled from tissue or cells at 3.5-second temporal resolution, with integrated enzyme assays enabling real-time quantification of glycerol (down to 1.9 fmol droplet<sup>-1</sup>). This high resolution revealed previously unreported oscillations in secreted glycerol at frequencies of 0.2 to 2.0 min<sup>-1</sup> (~30-300 s periods) present in the primary tissue but not in clustered cells. Low-level bursts (~50 fmol) released in basal conditions were contrasted with larger bursts (~300 fmol) during stimulation. Further, both fold changes and burst magnitudes were decreased in eWAT of aged and obese mice. These results, combined with immunostaining and photobleaching analyses, suggest that gap-junctional coupling or nerve cell innervation within the intact ex-vivo tissue explants play important roles in this apparent tissue-level, lipolytic synchronization. High-resolution, quantitative sampling by droplet microfluidics thus permitted unique biological information to be observed, giving an analytical framework poised for future studies of dynamic oscillatory function of adipose and other tissues.

scholarly journals Dissecting the immunosuppressive tumor microenvironments in Glioblastoma-on-a-Chip for optimized PD-1 immunotherapy

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Xin Cui ◽  
Chao Ma ◽  
Varshini Vasudevaraja ◽  
Jonathan Serrano ◽  
Jie Tong ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Immune Checkpoints ◽  
Patient Specific ◽  
Time Analysis ◽  
Tumor Microenvironments ◽  
Real Time Analysis ◽  
On Chip ◽  
Cell Death Protein ◽  
Cell Functionality ◽  
Tgf Β1

Programmed cell death protein-1 (PD-1) checkpoint immunotherapy efficacy remains unpredictable in glioblastoma (GBM) patients due to the genetic heterogeneity and immunosuppressive tumor microenvironments. Here, we report a microfluidics-based, patient-specific ‘GBM-on-a-Chip’ microphysiological system to dissect the heterogeneity of immunosuppressive tumor microenvironments and optimize anti-PD-1 immunotherapy for different GBM subtypes. Our clinical and experimental analyses demonstrated that molecularly distinct GBM subtypes have distinct epigenetic and immune signatures that may lead to different immunosuppressive mechanisms. The real-time analysis in GBM-on-a-Chip showed that mesenchymal GBM niche attracted low number of allogeneic CD154+CD8+ T-cells but abundant CD163+ tumor-associated macrophages (TAMs), and expressed elevated PD-1/PD-L1 immune checkpoints and TGF-β1, IL-10, and CSF-1 cytokines compared to proneural GBM. To enhance PD-1 inhibitor nivolumab efficacy, we co-administered a CSF-1R inhibitor BLZ945 to ablate CD163+ M2-TAMs and strengthened CD154+CD8+ T-cell functionality and GBM apoptosis on-chip. Our ex vivo patient-specific GBM-on-a-Chip provides an avenue for a personalized screening of immunotherapies for GBM patients.

scholarly journals Monash DaCRA fPET-fMRI: A DAtaset for Comparison of Radiotracer Administration for high temporal resolution functional FDG-PET

2021 ◽  
Author(s):  
Sharna D Jamadar ◽  
Emma X Liang ◽  
Shenjun Zhong ◽  
Phillip GD Ward ◽  
Alexandra Carey ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Glucose Uptake ◽  
Temporal Resolution ◽  
Emission Tomography ◽  
Constant Infusion ◽  
High Temporal Resolution ◽  
Bolus Infusion ◽  
Bold Fmri ◽  
Infusion Group ◽  
Positron Emission

Background: Functional [18F]-fluorodeoxyglucose positron emission tomography (FDG-fPET) is a new approach for measuring glucose uptake in the human brain. The goal of FDG-fPET is to maintain a constant plasma supply of radioactive FDG in order to track, with high temporal resolution, the dynamic uptake of glucose during neuronal activity that occurs in response to a task or at rest. FDG-fPET has most often been applied in simultaneous BOLD-fMRI/FDG-fPET (blood oxygenation level dependent functional MRI fluorodeoxyglucose functional positron emission tomography) imaging. BOLD-fMRI/FDG-fPET provides the capability to image the two primary sources of energetic dynamics in the brain, the cerebrovascular haemodynamic response and cerebral glucose uptake. Findings: In this Data Note, we describe an open access dataset, Monash DaCRA fPET-fMRI, which contrasts three radiotracer administration protocols for FDG-fPET: bolus, constant infusion, and hybrid bolus/infusion. Participants (n=5 in each group) were randomly assigned to each radiotracer administration protocol and underwent simultaneous BOLD-fMRI/FDG-fPET scanning while viewing a flickering checkerboard. The Bolus group received the full FDG dose in a standard bolus administration; the Infusion group received the full FDG dose as a slow infusion over the duration of the scan, and the Bolus-Infusion group received 50% of the FDG dose as bolus and 50% as constant infusion. We validate the dataset by contrasting plasma radioactivity, grey matter mean uptake, and task-related activity in the visual cortex. Conclusions: The Monash DaCRA fPET-fMRI dataset provides significant re-use value for researchers interested in the comparison of signal dynamics in fPET, and its relationship with fMRI task-evoked activity.

scholarly journals Compound- and fiber type-selective requirement of AMPKγ3 for insulin-independent glucose uptake in skeletal muscle

2021 ◽  
Author(s):  
Philipp Rhein ◽  
Eric M Desjardins ◽  
Ping Rong ◽  
Danial Ahwazi ◽  
Nicolas Bonhoure ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Oxygen Consumption ◽  
Blood Glucose ◽  
Glucose Uptake ◽  
Glucose Homeostasis ◽  
Ex Vivo ◽  
Fiber Type ◽  
Whole Body ◽  
Glucose Clearance

Objective: The metabolic master-switch AMP-activated protein kinase (AMPK) mediates insulin-independent glucose uptake in muscle and regulates the metabolic activity of brown and beige adipose tissue (BAT). The regulatory AMPKγ3 isoform is uniquely expressed in skeletal muscle and also potentially in BAT. Here, we investigated the role that AMPKγ3 plays in mediating skeletal muscle glucose uptake and whole-body glucose clearance in response to small-molecule activators that act on AMPK via distinct mechanisms. We also assessed if γ3 plays a role in adipose thermogenesis and browning. Methods: Global AMPKγ3 knockout (KO) mice were generated. A systematic whole-body, tissue and molecular phenotyping linked to glucose homeostasis was performed in γ3 KO and wild type (WT) mice. Glucose uptake in glycolytic and oxidative skeletal muscle ex vivo, as well as blood glucose clearance in response to small molecule AMPK activators that target nucleotide-binding domain of γ subunit (AICAR) and allosteric drug and metabolite (ADaM) site located at the interface of the α and β subunit (991, MK-8722) were assessed. Oxygen consumption, thermography, and molecular phenotyping with a β3-adrenergic receptor agonist (CL-316,243) treatment were performed to assess BAT thermogenesis, characteristics and function. Results: Genetic ablation of γ3 did not affect body weight, body composition, physical activity, and parameters associated with glucose homeostasis under chow or high fat diet. γ3 deficiency had no effect on fiber-type composition, mitochondrial content and integrity, or insulin-stimulated glucose uptake in skeletal muscle. Glycolytic muscles in γ3 KO mice showed a partial loss of AMPKα2 activity, which was associated with reduced levels of AMPKα2 and β2 subunit isoforms. Notably, γ3 deficiency resulted in a selective loss of AICAR-, but not MK-8722-induced blood glucose lowering in vivo and glucose uptake specifically in glycolytic muscles ex vivo. We detected γ3 in BAT and found that it preferentially interacts with α2 and β2. We observed no differences in oxygen consumption, thermogenesis, morphology of BAT and inguinal white adipose tissue (iWAT), or markers of BAT activity between WT and γ3 KO mice. Conclusions: These results demonstrate that γ3 plays a key role in mediating AICAR- but not ADaM site binding drug-stimulated blood glucose clearance and glucose uptake specifically in glycolytic skeletal muscle. We also showed that γ3 is dispensable for thermogenesis and browning of iWAT.

scholarly journals Apelin stimulates glucose uptake but not lipolysis in human adipose tissue ex vivo

2010 ◽  
Vol 46 (1) ◽  
pp. 21-28 ◽  
Author(s):  
C. Attane ◽  
D. Daviaud ◽  
C. Dray ◽  
R. Dusaulcy ◽  
M. Masseboeuf ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Glucose Uptake ◽  
Ex Vivo ◽  
Human Adipose Tissue

Multidetector-row Computed Tomography in the Assessment of Coronary Artery Disease – New Techniques and Insights

2010 ◽  
Vol 6 (2) ◽  
pp. 43 ◽  
Author(s):  
Andreas H Mahnken ◽  
Keyword(s):  
Computed Tomography ◽  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Data Acquisition ◽  
Temporal Resolution ◽  
High Temporal Resolution ◽  
Multidetector Row ◽  
Ct Scanners ◽  
Artery Disease ◽  
Cardiac Mdct

Over the last decade, cardiac computed tomography (CT) technology has experienced revolutionary changes and gained broad clinical acceptance in the work-up of patients suffering from coronary artery disease (CAD). Since cardiac multidetector-row CT (MDCT) was introduced in 1998, acquisition time, number of detector rows and spatial and temporal resolution have improved tremendously. Current developments in cardiac CT are focusing on low-dose cardiac scanning at ultra-high temporal resolution. Technically, there are two major approaches to achieving these goals: rapid data acquisition using dual-source CT scanners with high temporal resolution or volumetric data acquisition with 256/320-slice CT scanners. While each approach has specific advantages and disadvantages, both technologies foster the extension of cardiac MDCT beyond morphological imaging towards the functional assessment of CAD. This article examines current trends in the development of cardiac MDCT.

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