Ex vivo hyperpolarized MR spectroscopy on isolated renal tubular cells: A novel technique for cell energy phenotyping

Juul, Troels; Palm, Fredrik; Nielsen, Per Mose; Bertelsen, Lotte Bonde; Laustsen, Christoffer

doi:10.1002/mrm.26379

Cited by 6 publications

(3 citation statements)

References 30 publications

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“…Revisiting the reported rate constant CV of this system, a comparison with other literature investigating cells in various bioreactor and NMR systems would provide valuable insights for evaluating the current performance. The mean CV of control groups (

n \geq 3

) in six studies 18,23,25,26,37,40 along with our own findings (Figure S2) equaled

C_{V}^{mean} = 23 % \pm 15 %

(range 3%–46%). Details of the pooled data can be found in Table S2.…”

Section: Discussionsupporting

confidence: 78%

A continuous flow bioreactor system for high‐throughput hyperpolarized metabolic flux analysis

Christensen,

Holm,

Sanchez

et al. 2024

NMR in Biomedicine

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Hyperpolarized carbon‐13 labeled compounds are increasingly being used in medical MR imaging (MRI) and MR imaging (MRI) and spectroscopy (MRS) research, due to its ability to monitor tissue and cell metabolism in real‐time. Although radiological biomarkers are increasingly being considered as clinical indicators, biopsies are still considered the gold standard for a large variety of indications. Bioreactor systems can play an important role in biopsy examinations because of their ability to provide a physiochemical environment that is conducive for therapeutic response monitoring ex vivo. We demonstrate here a proof‐of‐concept bioreactor and microcoil receive array setup that allows for ex vivo preservation and metabolic NMR spectroscopy on up to three biopsy samples simultaneously, creating an easy‐to‐use and robust way to simultaneously run multisample carbon‐13 hyperpolarization experiments. Experiments using hyperpolarized [1‐13C]pyruvate on ML‐1 leukemic cells in the bioreactor setup were performed and the kinetic pyruvate‐to‐lactate rate constants () extracted. The coefficient of variation of the experimentally found s for five repeated experiments was . With this statistical power, treatment effects of 30%–40% change in lactate production could be easily differentiable with only a few hyperpolarization dissolutions on this setup. Furthermore, longitudinal experiments showed preservation of ML‐1 cells in the bioreactor setup for at least 6 h. Rat brain tissue slices were also seen to be preserved within the bioreactor for at least 1 h. This validation serves as the basis for further optimization and upscaling of the setup, which undoubtedly has huge potential in high‐throughput studies with various biomarkers and tissue types.

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n \geq 3

) in six studies 18,23,25,26,37,40 along with our own findings (Figure S2) equaled

C_{V}^{mean} = 23 % \pm 15 %

(range 3%–46%). Details of the pooled data can be found in Table S2.…”

Section: Discussionsupporting

confidence: 78%

A continuous flow bioreactor system for high‐throughput hyperpolarized metabolic flux analysis

Christensen,

Holm,

Sanchez

et al. 2024

NMR in Biomedicine

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“…In principle any small molecular probe can be hyperpolarized as long as they contain a nuclear spin, typically 13 C2021. Currently there is an large array of commercial available hyperpolarized of 13 C-labeled molecules which have been utilized in many different animal models of cancer2223, myocardial ischemia242526 and renal diseases27282930, and more recently in patients and healthy volunteers3132 Additionally, [1,4- 13 C]fumarate has been shown to be a reliable imaging biomarker for monitoring cellular necrosis33 in a rat model of xenograft tumors and subsequently in a rat model with folic acid-induced AKI34. These previous results showed an increased 13 C-malate signal in kidneys with progressive tubular necrosis.…”

mentioning

confidence: 99%

Fumarase activity: an in vivo and in vitro biomarker for acute kidney injury

Nielsen

Eldirdiri

Bertelsen

et al. 2017

Sci Rep

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Renal ischemia/reperfusion injury (IRI) is a leading cause of acute kidney injury (AKI), and at present, there is a lack of reliable biomarkers that can diagnose AKI and measure early progression because the commonly used methods cannot evaluate single-kidney IRI. Hyperpolarized [1,4-13C2]fumarate conversion to [1,4-13C2]malate by fumarase has been proposed as a measure of necrosis in rat tumor models and in chemically induced AKI rats. Here we show that the degradation of cell membranes in connection with necrosis leads to elevated fumarase activity in plasma and urine and secondly that hyperpolarized [1,4-13C2]malate production 24 h after reperfusion correlates with renal necrosis in a 40-min unilateral ischemic rat model. Fumarase activity screening on bio-fluids can detect injury severity, in bilateral as well as unilateral AKI models, differentiating moderate and severe AKI as well as short- and long-term AKI. Furthermore after verification of renal injury by bio-fluid analysis the precise injury location can be monitored by in vivo measurements of the fumarase activity non-invasively by hyperpolarized [1,4-13C]fumarate MR imaging. The combined in vitro and in vivo biomarker of AKI responds to the essential requirements for a new reliable biomarker of AKI.

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“…Freshly isolated rat renal cells have been used in toxicological in vitro studies [ 25 , 26 , 27 ], physiological in vitro studies [ 28 , 29 ], metabolic phenotyping [ 30 ], and experimental studies on drug metabolism [ 31 , 32 ]. Although experimental studies on peptide accumulation in the kidney may be successfully performed in vitro using selected cell lines, such as OK (opossum kidney) cells [ 8 ], isolated rat renal cells might also help analyze the renal handling of xenobiotics, including radiolabeled compounds [ 33 ].…”

Section: Discussionmentioning

confidence: 99%

Validation of Freshly Isolated Rat Renal Cells as a Tool for Preclinical Assessment of Radiolabeled Receptor-Specific Peptide Uptake in the Kidney

et al. 2023

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The synthetic analogs of regulatory peptides radiolabeled with adequate radionuclides are perspective tools in nuclear medicine. However, undesirable uptake and retention in the kidney limit their application. Specific in vitro methods are used to evaluate undesirable renal accumulation. Therefore, we investigated the usefulness of freshly isolated rat renal cells for evaluating renal cellular uptake of receptor-specific peptide analogs. Special attention was given to megalin as this transport system is an important contributor to the active renal uptake of the peptides. Freshly isolated renal cells were obtained from native rat kidneys by the collagenase method. Compounds with known accumulation in renal cells were used to verify the viability of cellular transport systems. Megalin expressions in isolated rat renal cells were compared to two other potential renal cell models by Western blotting. Specific tubular cell markers were used to confirm the presence of proximal tubular cells expressing megalin in isolated rat renal cell preparations by immunohistochemistry. Colocalization experiments on isolated rat kidney cells confirmed the presence of proximal tubular cells bearing megalin in preparations. The applicability of the method was tested by an accumulation study with several analogs of somatostatin and gastrin labeled with indium-111 or lutetium-177. Therefore, isolated rat renal cells may be an effective screening tool for in vitro analyses of renal uptake and comparative renal accumulation studies of radiolabeled peptides or other radiolabeled compounds with potential nephrotoxicity.

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Ex vivo hyperpolarized MR spectroscopy on isolated renal tubular cells: A novel technique for cell energy phenotyping

Cited by 6 publications

References 30 publications

A continuous flow bioreactor system for high‐throughput hyperpolarized metabolic flux analysis

A continuous flow bioreactor system for high‐throughput hyperpolarized metabolic flux analysis

Fumarase activity: an in vivo and in vitro biomarker for acute kidney injury

Validation of Freshly Isolated Rat Renal Cells as a Tool for Preclinical Assessment of Radiolabeled Receptor-Specific Peptide Uptake in the Kidney

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