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McDonough MH, Stocker SL, Kippin T, Meiring W, Plaxco KW. Using seconds-resolved pharmacokinetic datasets to assess pharmacokinetic models encompassing time-varying physiology. Br J Clin Pharmacol 2023; 89:2798-2812. [PMID: 37186478 PMCID: PMC10799768 DOI: 10.1111/bcp.15756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 04/04/2023] [Accepted: 04/10/2023] [Indexed: 05/17/2023] Open
Abstract
AIM Pharmacokinetics have historically been assessed using drug concentration data obtained via blood draws and bench-top analysis. The cumbersome nature of these typically constrains studies to at most a dozen concentration measurements per dosing event. This, in turn, limits our statistical power in the detection of hours-scale, time-varying physiological processes. Given the recent advent of in vivo electrochemical aptamer-based (EAB) sensors, however, we can now obtain hundreds of concentration measurements per administration. Our aim in this paper was to assess the ability of these time-dense datasets to describe time-varying pharmacokinetic models with good statistical significance. METHODS We used seconds-resolved measurements of plasma tobramycin concentrations in rats to statistically compare traditional one- and two-compartmental pharmacokinetic models to new models in which the proportional relationship between a drug's plasma concentration and its elimination rate varies in response to changing kidney function. RESULTS We found that a modified one-compartment model in which the proportionality between the plasma concentration of tobramycin and its elimination rate falls reciprocally with time either meets or is preferred over the standard two-compartment pharmacokinetic model for half of the datasets characterized. When we reduced the impact of the drug's rapid distribution phase on the model, this one-compartment, time-varying model was statistically preferred over the standard one-compartment model for 80% of our datasets. CONCLUSIONS Our results highlight both the impact that simple physiological changes (such as varying kidney function) can have on drug pharmacokinetics and the ability of high-time resolution EAB sensor measurements to identify such impacts.
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Affiliation(s)
- Matthew H. McDonough
- Department of Statistics and Applied Probability, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Sophie L. Stocker
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Camperdown NSW 2006, Sydney, Australia
- St Vincent’s Clinical School, University of New South Wales, Sydney, Australia
| | - Tod Kippin
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA 93106, USA
- The Neuroscience Research Institute and Department of Molecular Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Wendy Meiring
- Department of Statistics and Applied Probability, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Kevin W. Plaxco
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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2
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Rosner MH, Sprangers B, Sandhu G, Malyszko J. Glomerular Filtration Rate Measurement and Chemotherapy Dosing. Semin Nephrol 2023; 42:151340. [PMID: 37086497 DOI: 10.1016/j.semnephrol.2023.151340] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
Abstract
Many chemotherapeutic drugs used to treat malignancies undergo renal clearance. Thus, accurate knowledge of kidney function is critical to ensure proper dosing, maximize efficacy, and minimize toxicity of drugs that often have a narrow therapeutic index. Making this issue more salient is the fact that impaired kidney function, as assessed by glomerular filtration rate (GFR), is encountered commonly in patients with cancer. Recent data and expert guidelines recommend the use of the Chronic Kidney Disease-Epidemiology Collaboration equation to guide the assessment of kidney function, except when directly measured GFR is clinically necessary. Controversies regarding the measurement of kidney function include the use of race in this equation, indexing to body surface area, and dosing of medications based on stages of chronic kidney disease versus more discrete values of estimated GFR. The development of accurate, real-time GFR measures may hold great promise in allowing for more accurate dosing of these important drugs.
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Affiliation(s)
- Mitchell H Rosner
- Division of Nephrology, University of Virginia Health, Charlottesville, VA.
| | - Ben Sprangers
- Department of Microbiology, Immunology and Transplantation, Laboratory of Molecular Immunology, Rega Institute for Medical Research, KU Leuven, Division of Nephrology, University Hospitals Leuven, Leuven, Belgium
| | - Geeta Sandhu
- eviQ, Cancer Institute New South Wales, St Leonards, New South Wales, Australia
| | - Jolanta Malyszko
- Department of Nephrology, Dialysis and Internal Medicine, Warsaw Medical University, Warsaw, Poland
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3
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Molitoris BA, Sandoval RM, Wagner MC. Intravital Multiphoton Microscopy as a Tool for Studying Renal Physiology, Pathophysiology and Therapeutics. Front Physiol 2022; 13:827280. [PMID: 35399274 PMCID: PMC8988037 DOI: 10.3389/fphys.2022.827280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Intravital multiphoton microscopy has empowered investigators to study dynamic cell and subcellular processes in vivo within normal and disease organs. Advances in hardware, software, optics, transgenics and fluorescent probe design and development have enabled new quantitative approaches to create a disruptive technology pioneering advances in understanding of normal biology, disease pathophysiology and therapies. Offering superior spatial and temporal resolution with high sensitivity, investigators can follow multiple processes simultaneously and observe complex interactions between different cell types, intracellular organelles, proteins and track molecules for cellular uptake, intracellular trafficking, and metabolism in a cell specific fashion. The technique has been utilized in the kidney to quantify multiple dynamic processes including capillary flow, permeability, glomerular function, proximal tubule processes and determine the effects of diseases and therapeutic mechanisms. Limitations include the depth of tissue penetration with loss of sensitivity and resolution due to scattered emitted light. Tissue clearing technology has virtually eliminated penetration issues for fixed tissue studies. Use of multiphoton microscopy in preclinical animal models offers distinct advantages resulting in new insights into physiologic processes and the pathophysiology and treatment of diseases.
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4
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Ratiometric two-photon fluorescence probes for sensing, imaging and biomedicine applications at living cell and small animal levels. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214114] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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5
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Swolinsky JS, Nerger NP, Leistner DM, Edelmann F, Knebel F, Tuvshinbat E, Lemke C, Roehle R, Haase M, Costanzo MR, Rauch G, Mitrovic V, Gasanin E, Meier D, McCullough PA, Eckardt K, Molitoris BA, Schmidt‐Ott KM. Serum creatinine and cystatin C-based estimates of glomerular filtration rate are misleading in acute heart failure. ESC Heart Fail 2021; 8:3070-3081. [PMID: 33955699 PMCID: PMC8318462 DOI: 10.1002/ehf2.13404] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/19/2021] [Accepted: 04/22/2021] [Indexed: 12/13/2022] Open
Abstract
AIMS We aimed to test whether the endogenous filtration markers serum creatinine or cystatin C and equation-based estimates of glomerular filtration rate (GFR) based on these markers appropriately reflect changes of measured GFR in patients with acute heart failure. METHODS In this prospective cohort study of 50 hospitalized acute heart failure patients undergoing decongestive therapy, we applied an intravenous visible fluorescent injectate (VFI), consisting of a low molecular weight component to measure GFR and a high molecular weight component to correct for measured plasma volume. Thirty-eight patients had two sequential GFR measurements 48 h apart. The co-primary endpoints of the study were safety of VFI and plasma stability of the high molecular weight component. A key secondary endpoint was to compare changes in measured GFR (mGFR) to changes of serum creatinine, cystatin C and estimated GFR. RESULTS VFI-based GFR measurements were safe and consistent with plasma stability of the high molecular weight component and glomerular filtration of the low molecular weight component. Filtration marker-based point estimates of GFR, when compared with mGFR, provided only moderate correlation (Pearson's r, range 0.80-0.88, depending on equation used), precision (r2 , range 0.65-0.78) and accuracy (56%-74% of estimates scored within 30% of mGFR). Correlations of 48-h changes GFR estimates and changes of mGFR were significant (P < 0.05) but weak (Pearson's r, range 0.35-0.39). Observed decreases of eGFR by more than 15% had a low sensitivity (range 38%-46%, depending on equation used) in detecting true worsening mGFR, defined by a >15% decrease in mGFR. CONCLUSIONS In patients hospitalized for acute heart failure, serum creatinine- and cystatin C-based predictions performed poorly in detecting actual changes of GFR. These data challenge current clinical strategies to evaluate dynamics of kidney function in acute heart failure.
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Affiliation(s)
- Jutta S. Swolinsky
- Department of Nephrology and Medical Intensive CareCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
| | - Niklas P. Nerger
- Department of Nephrology and Medical Intensive CareCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
| | - David M. Leistner
- Department of Internal Medicine and CardiologyCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu Berlin, Campus Benjamin FranklinBerlinGermany
- Clinical Research UnitBerlin Institute of Health (BIH) at Charité – Universitätsmedizin BerlinBerlinGermany
- DZHK (German Centre for Cardiovascular Research) Partner Site BerlinBerlinGermany
| | - Frank Edelmann
- Clinical Research UnitBerlin Institute of Health (BIH) at Charité – Universitätsmedizin BerlinBerlinGermany
- DZHK (German Centre for Cardiovascular Research) Partner Site BerlinBerlinGermany
- Department of Internal Medicine and CardiologyCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu Berlin, Campus Virchow KlinikumBerlinGermany
| | - Fabian Knebel
- Department of Cardiology and AngiologyCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu Berlin, Campus MitteBerlinGermany
| | - Enkhtuvshin Tuvshinbat
- Department of Nephrology and Medical Intensive CareCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
| | - Caroline Lemke
- Department of Nephrology and Medical Intensive CareCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
| | - Robert Roehle
- Clinical Research UnitBerlin Institute of Health (BIH) at Charité – Universitätsmedizin BerlinBerlinGermany
- Institute of Biometry and Clinical EpidemiologyCharité – Universtitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- Coordinating Center for Clinical StudiesCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
| | - Michael Haase
- Faculty of MedicineOtto von‐Guericke‐University MagdeburgMagdeburgGermany
| | | | - Geraldine Rauch
- Clinical Research UnitBerlin Institute of Health (BIH) at Charité – Universitätsmedizin BerlinBerlinGermany
- Institute of Biometry and Clinical EpidemiologyCharité – Universtitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
| | | | - Edis Gasanin
- Department of CardiologyKerckhoff KlinikBad NauheimGermany
| | | | - Peter A. McCullough
- Baylor University Medical Center, Baylor Heart and Vascular HospitalBaylor Heart and Vascular InstituteDallasTXUSA
| | - Kai‐Uwe Eckardt
- Department of Nephrology and Medical Intensive CareCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
| | | | - Kai M. Schmidt‐Ott
- Department of Nephrology and Medical Intensive CareCharité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- Clinical Research UnitBerlin Institute of Health (BIH) at Charité – Universitätsmedizin BerlinBerlinGermany
- Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany
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6
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Real-time glomerular filtration rate: improving sensitivity, accuracy and prognostic value in acute kidney injury. Curr Opin Crit Care 2021; 26:549-555. [PMID: 33002974 DOI: 10.1097/mcc.0000000000000770] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW Acute kidney injury (AKI) is common and associated with high patient mortality, and accelerated progression to chronic kidney disease. Our ability to diagnose and stratify patients with AKI is paramount for translational progress. Unfortunately, currently available methods have major pitfalls. Serum creatinine is an insensitive functional biomarker of AKI, slow to register the event and influenced by multiple variables. Cystatin C, a proposed alternative, requires long laboratory processing and also lacks specificity. Other techniques are either very cumbersome (inuline, iohexol) or involve administration of radioactive products, and are therefore, not applicable on a large scale. RECENT FINDINGS The development of two optical measurement techniques utilizing novel minimally invasive techniques to quantify kidney function, independent of serum or urinary measurements is advancing. Utilization of both one and two compartmental models, as well as continuous monitoring, are being developed. SUMMARY The clinical utility of rapid GFR measurements in AKI patients remains unknown as these disruptive technologies have not been tested in studies exploring clinical outcomes. However, these approaches have the potential to improve our understanding of AKI and clinical care. This overdue technology has the potential to individualize patient care and foster therapeutic success in AKI.
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7
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Abstract
Kidneys are highly aerobic organs and their function is tightly coupled to mitochondrial energy production. Renal tubular cells, particularly the proximal tubule (PT), require an abundance of mitochondria to provide sufficient energy for regulating fluid and electrolyte balance. Meanwhile, mitochondrial defects are implicated in a range of different kidney diseases. Multiphoton microscopy (MP) is a powerful tool that allows detailed study of mitochondrial morphology, dynamics, and function in kidney tissue. Here, we describe how MP can be used to image mitochondria in kidney tubular cells, either ex vivo in tissue slices or in vivo in living rodents, using both endogenous and exogenous fluorescent molecules. Moreover, changes in mitochondrial signals can be followed in real time in response to different insults or stimuli, in parallel with other important readouts of kidney tubular function, such as solute uptake and trafficking.
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Affiliation(s)
- Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Susan Ghazi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland.
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8
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Zheng Z, Pan X, Xu J, Wu Z, Zhang Y, Wang K. Advances in tracking of polysaccharides in vivo: Labeling strategies, potential factors and applications based on pharmacokinetic characteristics. Int J Biol Macromol 2020; 163:1403-1420. [DOI: 10.1016/j.ijbiomac.2020.07.210] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/25/2020] [Accepted: 07/26/2020] [Indexed: 12/14/2022]
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9
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Ranjit S, Lanzanò L, Libby AE, Gratton E, Levi M. Advances in fluorescence microscopy techniques to study kidney function. Nat Rev Nephrol 2020; 17:128-144. [PMID: 32948857 DOI: 10.1038/s41581-020-00337-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2020] [Indexed: 02/07/2023]
Abstract
Fluorescence microscopy, in particular immunofluorescence microscopy, has been used extensively for the assessment of kidney function and pathology for both research and diagnostic purposes. The development of confocal microscopy in the 1950s enabled imaging of live cells and intravital imaging of the kidney; however, confocal microscopy is limited by its maximal spatial resolution and depth. More recent advances in fluorescence microscopy techniques have enabled increasingly detailed assessment of kidney structure and provided extraordinary insights into kidney function. For example, nanoscale precise imaging by rapid beam oscillation (nSPIRO) is a super-resolution microscopy technique that was originally developed for functional imaging of kidney microvilli and enables detection of dynamic physiological events in the kidney. A variety of techniques such as fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS) and Förster resonance energy transfer (FRET) enable assessment of interaction between proteins. The emergence of other super-resolution techniques, including super-resolution stimulated emission depletion (STED), photoactivated localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM) and structured illumination microscopy (SIM), has enabled functional imaging of cellular and subcellular organelles at ≤50 nm resolution. The deep imaging via emission recovery (DIVER) detector allows deep, label-free and high-sensitivity imaging of second harmonics, enabling assessment of processes such as fibrosis, whereas fluorescence lifetime imaging microscopy (FLIM) enables assessment of metabolic processes.
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Affiliation(s)
- Suman Ranjit
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA. .,Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA.
| | - Luca Lanzanò
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy.,Department of Physics and Astronomy "Ettore Majorana", University of Catania, Catania, Italy
| | - Andrew E Libby
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA.
| | - Moshe Levi
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA.
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10
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McMahon BA, Rosner MH. GFR Measurement and Chemotherapy Dosing in Patients with Kidney Disease and Cancer. KIDNEY360 2020; 1:141-150. [PMID: 35372903 PMCID: PMC8809099 DOI: 10.34067/kid.0000952019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Chemotherapeutic agents require precise dosing to ensure optimal efficacy and minimize complications. For those agents that are removed from the body by the kidney, accurate knowledge of GFR is critical. In addition, GFR needs to be determined rapidly, easily, and, if possible, with little additional cost. The ability to easily measure GFR also allows for rapid detection of nephrotoxicity. Current methodologies include direct clearance measurement of an indicator substance or estimation of creatinine clearance or GFR through regression equations that use a serum marker, such as creatinine or cystatin C. These methodologies all have shortfalls and limitations, some of which are specific to the patient with cancer. Newer methodologies that directly measure GFR are in clinical trials and offer the ability to rapidly and noninvasively provide accurate estimates of drug clearance as well as detection of nephrotoxicity. These methods offer the opportunity to refine drug dosing and improve outcomes.
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Affiliation(s)
- Blaithin A. McMahon
- Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina; and
| | - Mitchell H. Rosner
- Division of Nephrology, University of Virginia Health System, Charlottesville, Virginia
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11
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Plunkett S, El Khatib M, Şencan İ, Porter JE, Kumar ATN, Collins JE, SakadŽić S, Vinogradov SA. In vivo deep-tissue microscopy with UCNP/Janus-dendrimers as imaging probes: resolution at depth and feasibility of ratiometric sensing. NANOSCALE 2020; 12:2657-2672. [PMID: 31939953 PMCID: PMC7101076 DOI: 10.1039/c9nr07778b] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Lanthanide-based upconverting nanoparticles (UCNPs) are known for their remarkable ability to convert near-infrared energy into higher energy light, offering an attractive platform for construction of biological imaging probes. Here we focus on in vivo high-resolution microscopy - an application for which the opportunity to carry out excitation at low photon fluxes in non-linear regime makes UCNPs stand out among all multiphoton probes. To create biocompatible nanoparticles we employed Janus-type dendrimers as surface ligands, featuring multiple carboxylates on one 'face' of the molecule, polyethylene glycol (PEG) residues on another and Eriochrome Cyanine R dye as the core. The UCNP/Janus-dendrimers showed outstanding performance as vascular markers, allowing for depth-resolved mapping of individual capillaries in the mouse brain down to a remarkable depth of ∼1000 μm under continuous wave (CW) excitation with powers not exceeding 20 mW. Using a posteriori deconvolution, high-resolution images could be obtained even at high scanning speeds in spite of the blurring caused by the long luminescence lifetimes of the lanthanide ions. Secondly, the new UCNP/dendrimers allowed us to evaluate the feasibility of quantitative analyte imaging in vivo using a popular ratiometric UCNP-to-ligand excitation energy transfer (EET) scheme. Our results show that the ratio of UCNP emission bands, which for quantitative sensing should respond selectively to the analyte of interest, is also strongly affected by optical heterogeneities of the medium. On the other hand, the luminescence decay times of UCNPs, which are independent of the medium properties, are modulated via EET only insignificantly. As such, quantitative analyte sensing in biological tissues with UCNP-based probes still remains a challenge.
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Affiliation(s)
- Shane Plunkett
- Department of Biochemistry and Biophysics, Perelman School of Medicine, and Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Mirna El Khatib
- Department of Biochemistry and Biophysics, Perelman School of Medicine, and Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - İkbal Şencan
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA 02129, USA
| | - Jason E Porter
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA 02129, USA
| | - Anand T N Kumar
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA 02129, USA
| | | | - Sava SakadŽić
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA 02129, USA
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, and Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA.
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12
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Abstract
Glomerular filtration rate (GFR) is considered the gold standard to test kidney function. However, the serial blood and/or urine sample collection required for the calculation of the GFR is stressful for the animal and time consuming for the experimenter. Here, we describe a transcutaneous assessment of renal function in conscious animals that does not require plasma or urine sampling and/or deep anesthesia. For the measurement, we use a near-infrared (NIR) device that records the excretion kinetic of the renal marker ABZWCY-HPβCD. ABZWCY-HPβCD is a new hydrophilic, stable, and nontoxic NIR fluorescent agent that can be used as a renal marker as it is filtrated and completely excreted through the kidneys into the urine without reabsorption or secretion and without accumulation in the skin. The data recorded in the device are then analyzed with "GFRmeasure," an open-source, freely downloadable, and user-friendly software.
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13
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Křivohlavá R, Neuhӧferová E, Jakobsen KQ, Benson V. Knockdown of microRNA-135b in Mammary Carcinoma by Targeted Nanodiamonds: Potentials and Pitfalls of In Vivo Applications. NANOMATERIALS 2019; 9:nano9060866. [PMID: 31181619 PMCID: PMC6632128 DOI: 10.3390/nano9060866] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 12/26/2022]
Abstract
Nanodiamonds (ND) serve as RNA carriers with potential for in vivo application. ND coatings and their administration strategy significantly change their fate, toxicity, and effectivity within a multicellular system. Our goal was to develop multiple ND coating for effective RNA delivery in vivo. Our final complex (NDA135b) consisted of ND, polymer, antisense RNA, and transferrin. We aimed (i) to assess if a tumor-specific coating promotes NDA135b tumor accumulation and effective inhibition of oncogenic microRNA-135b and (ii) to outline off-targets and immune cell interactions. First, we tested NDA135b toxicity and effectivity in tumorospheres co-cultured with immune cells ex vivo. We found NDA135b to target tumor cells, but it binds also to granulocytes. Then, we followed with NDA135b intravenous and intratumoral applications in tumor-bearing animals in vivo. Application of NDA135b in vivo led to the effective knockdown of microRNA-135b in tumor tissue regardless administration. Only intravenous application resulted in NDA135b circulation in peripheral blood and urine and the decreased granularity of splenocytes. Our data show that localized intratumoral application of NDA135b represents a suitable and safe approach for in vivo application of nanodiamond-based constructs. Systemic intravenous application led to an interaction of NDA135b with bio-interface, and needs further examination regarding its safety.
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Affiliation(s)
- Romana Křivohlavá
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Eva Neuhӧferová
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Katrine Q Jakobsen
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Veronika Benson
- Institute of Microbiology of the CAS, v.v.i., Videnska 1083, 142 20 Prague 4, Czech Republic.
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14
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Hauser-Kawaguchi A, Milne M, Li F, Lee T, Luyt L. The development of a near infrared inulin optical probe for measuring glomerular filtration rate. Int J Biol Macromol 2019; 123:255-260. [DOI: 10.1016/j.ijbiomac.2018.11.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/30/2018] [Accepted: 11/07/2018] [Indexed: 01/23/2023]
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15
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Pickering JW, Blunt IRH, Than MP. Acute Kidney Injury and mortality prognosis in Acute Coronary Syndrome patients: A meta-analysis. Nephrology (Carlton) 2018; 23:237-246. [PMID: 27990707 DOI: 10.1111/nep.12984] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 01/06/2023]
Abstract
AIM The aim of this study is to provide a robust estimate of mortality risk in acute coronary syndrome (ACS)-associated acute kidney injury (AKI) to inform clinical practice and policy. METHODS A meta-analysis of cohort studies evaluating outcomes of ACS and which reported AKI and AKI-associated mortality. Studies were excluded if they incorporated patients not admitted through the emergency department (i.e. for elective procedures), were limited to cardiogenic shock or cardiac arrest, or relied on registry data for outcomes without further adjudication. The predictor was ACS-associated AKI and outcomes early (30 day or in-hospital) mortality and late-mortality (post-hospital discharge). RESULTS Thirty-six studies with 37 unique cohorts comprising 100 476 patients were included. The pooled rate of ACS-associated AKI was 15.8%. In 32 cohorts reporting early mortality, the crude early mortality rate was 15.0% amongst those with AKI compared with 2.0% amongst those without AKI. The pooled estimate of the relative risk of AKI-associated early mortality was 4.1 (95% confidence interval: 3.3 to 5.0) with high heterogeneity between studies (I 2 = 84% (61% to 88%)). When heterogeneity was accounted for mathematically using credibility ceilings, the risk of mortality was lower, but still clinically significant (3.1 (2.6 to 3.6)). In 19 cohorts reporting late mortality (1 to 10 years), the relative risk of AKI-associated mortality was 2.6 (2.0 to 3.3) with moderate heterogeneity (I 2 = 65 % [35% to 88%]). Following application of credibility ceiling relative risk estimate dropped to 2.2 (1.9 to 2.6). CONCLUSIONS Acute coronary syndrome-associated AKI is associated with more than a three-fold increase in early mortality and more than two-fold in long-term mortality.
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Affiliation(s)
- John W Pickering
- Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand.,Emergency Department, Christchurch hospital, Christchurch, New Zealand
| | | | - Martin P Than
- Emergency Department, Christchurch hospital, Christchurch, New Zealand
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16
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Rizk DV, Meier D, Sandoval RM, Chacana T, Reilly ES, Seegmiller JC, DeNoia E, Strickland JS, Muldoon J, Molitoris BA. A Novel Method for Rapid Bedside Measurement of GFR. J Am Soc Nephrol 2018; 29:1609-1613. [PMID: 29748326 DOI: 10.1681/asn.2018020160] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/17/2018] [Indexed: 01/01/2023] Open
Abstract
Background Direct quantitative measurement of GFR (mGFR) remains a specialized task primarily performed in research settings. Multiple formulas for estimating GFR have been developed that use the readily available endogenous biomarkers creatinine and/or cystatin C. However, eGFR formulas have limitations, and an accurate mGFR is necessary in some clinical situations and for certain patient populations. We conducted a prospective, open-label study to evaluate a novel rapid technique for determining plasma volume and mGFR.Methods We developed a new exogenous biomarker, visible fluorescent injectate (VFI), consisting of a large 150-kD rhodamine derivative and small 5-kD fluorescein carboxymethylated dextrans. After a single intravenous injection of VFI, plasma volume and mGFR can be determined on the basis of the plasma pharmacokinetics of the rhodamine derivative and fluorescein carboxymethylated dextrans, respectively. In this study involving 32 adults with normal kidney function (n=16), CKD stage 3 (n=8), or CKD stage 4 (n=8), we compared VFI-based mGFR values with values obtained by measuring iohexol plasma disappearance. VFI-based mGFR required three 0.5-ml blood draws over 3 hours; iohexol-based mGFR required five samples taken over 6 hours. Eight healthy participants received repeat VFI injections at 24 hours.Results VFI-based mGFR values showed close linear correlation with the iohexol-based mGFR values in all participants. Injections were well tolerated, including when given on consecutive days. No serious adverse events were reported. VFI-based mGFR was highly reproducible.Conclusions The VFI-based approach allows for the rapid determination of mGFR at the bedside while maintaining patient safety and measurement accuracy and reproducibility.
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Affiliation(s)
- Dana V Rizk
- Nephrology Division, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama;
| | | | - Ruben M Sandoval
- FAST BioMedical, Carmel, Indiana.,Nephrology Division, Department of Medicine, Indiana University, Indianapolis, Indiana
| | - Teresa Chacana
- Nephrology Division, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Jesse C Seegmiller
- Advanced Research and Diagnostics Laboratory, University of Minnesota, Minneapolis, Minnesota; and
| | | | | | | | - Bruce A Molitoris
- FAST BioMedical, Carmel, Indiana.,Nephrology Division, Department of Medicine, Indiana University, Indianapolis, Indiana
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17
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Bjornstad P, Karger AB, Maahs DM. Measured GFR in Routine Clinical Practice-The Promise of Dried Blood Spots. Adv Chronic Kidney Dis 2018; 25:76-83. [PMID: 29499891 DOI: 10.1053/j.ackd.2017.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/17/2017] [Accepted: 09/20/2017] [Indexed: 12/31/2022]
Abstract
Accurate determination of glomerular filtration rate (GFR) is crucial for the diagnosis of kidney disease. Estimated GFR (eGFR) calculated by serum creatinine and/or cystatin C is a mainstay in clinical practice and epidemiologic research but lacks precision and accuracy until GFR <60 mL/min/1.73 m2. Furthermore, eGFR may not precisely and accurately represent changes in GFR longitudinally. The lack of precision and accuracy is of concern in populations at high risk for kidney disease, as the dissociation between changes in eGFR and GFR may lead to missed diagnoses of early kidney disease. Therefore, improved methods to quantify GFR are needed. Whereas direct measures of GFR have been too cumbersome for screening and ambulatory care, a practical method of measuring GFR by iohexol clearance using dried capillary blood spots exists. In this review, we examine the current literature and data addressing GFR measurements by dried capillary blood spots and its potential application in high-risk groups.
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18
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Moore JK, Chen J, Pan H, Gaut JP, Jain S, Wickline SA. Quantification of vascular damage in acute kidney injury with fluorine magnetic resonance imaging and spectroscopy. Magn Reson Med 2017; 79:3144-3153. [PMID: 29148253 DOI: 10.1002/mrm.26985] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/02/2017] [Accepted: 10/03/2017] [Indexed: 12/28/2022]
Abstract
PURPOSE To design a fluorine MRI/MR spectroscopy approach to quantify renal vascular damage after ischemia-reperfusion injury, and the therapeutic response to antithrombin nanoparticles (NPs) to protect kidney function. METHODS A total of 53 rats underwent 45 min of bilateral renal artery occlusion and were treated at reperfusion with either plain perfluorocarbon NPs or NPs functionalized with a direct thrombin inhibitor (PPACK:phenyalanine-proline-arginine-chloromethylketone). Three hours after reperfusion, kidneys underwent ex vivo fluorine MRI/MR spectroscopy at 4.7 T to quantify the extent and volume of trapped NPs, as an index of vascular damage and ischemia-reperfusion injury. Microscopic evaluation of structural damage and NP trapping in non-reperfused renal segments was performed. Serum creatinine was quantified serially over 7 days. RESULTS The damaged renal cortico-medullary junction trapped a significant volume of NPs (P = 0.04), which correlated linearly (r = 0.64) with the severity of kidney injury 3 h after reperfusion. Despite global large vessel reperfusion, non-reperfusion in medullary peritubular capillaries was confirmed by MRI and microscopy, indicative of continuing hypoxia due to vascular compromise. Treatment of animals with PPACK NPs after acute kidney injury did not accelerate kidney functional recovery. CONCLUSIONS Quantification of ischemia-reperfusion injury after acute kidney injury with fluorine MRI/MR spectroscopy of perfluorocarbon NPs objectively depicts the extent and severity of vascular injury and its linear relationship to renal dysfunction. The lack of kidney function improvement after early posttreatment thrombin inhibition confirms the rapid onset of ischemia-reperfusion injury as a consequence of vascular damage and non-reperfusion. The prolongation of medullary ischemia renders cortico-medullary tubular structures susceptible to continued necrosis despite restoration of large vessel flow, which suggests limitations to acute interventions after acute kidney injury, designed to interdict renal tubular damage. Magn Reson Med 79:3144-3153, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jeremy K Moore
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Junjie Chen
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hua Pan
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Joseph P Gaut
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sanjay Jain
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Samuel A Wickline
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University, St. Louis, Missouri, USA.,Department of Cardiovascular Science, University of South Florida, Tampa, Florida, USA.,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA
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19
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Press AT, Butans MJ, Haider TP, Weber C, Neugebauer S, Kiehntopf M, Schubert US, Clemens MG, Bauer M, Kortgen A. Fast simultaneous assessment of renal and liver function using polymethine dyes in animal models of chronic and acute organ injury. Sci Rep 2017; 7:15397. [PMID: 29133918 PMCID: PMC5684357 DOI: 10.1038/s41598-017-14987-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/19/2017] [Indexed: 12/12/2022] Open
Abstract
Simultaneous assessment of excretory liver and kidney function is still an unmet need in experimental stress models as well as in critical care. The aim of the study was to characterize two polymethine-dyes potentially suitable for this purpose in vivo. Plasma disappearance rate and elimination measurements of simultaneously injected fluorescent dyes DY-780 (hepato-biliary elimination) and DY-654(renal elimination) were conducted using catheter techniques and intravital microscopy in animals subjected to different organ injuries, i.e. polymicrobial sepsis by peritoneal contamination and infection, ischemia-reperfusion-injury and glycerol-induced acute kidney-injury. DY-780 and DY-654 showed organ specific and determined elimination routes in both healthy and diseased animals. They can be measured simultaneously using near-infrared imaging and spectrophotometry. Plasma-disappearance rates of DY-780 and DY-654 are superior to conventional biomarkers in indicating hepatic or kidney dysfunction in different animal models. Greatest impact on liver function was found in animals with polymicrobial sepsis whereas glomerular damage due to glycerol-induced kidney-injury had strongest impact on DY-654 elimination. We therefore conclude that hepatic elimination and renal filtration can be assessed in rodents measuring plasma-disappearance rates of both dyes. Further, assessment of organ dysfunction by polymethine dyes correlates with, but outperforms conventional biomarkers regarding sensitivity and the option of spatial resolution if biophotonic strategies are applied. Polymethine-dye clearance thereby allows sensitive point-of-care assessment of both organ functions simultaneously.
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Affiliation(s)
- A T Press
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - M J Butans
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - T P Haider
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - C Weber
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - S Neugebauer
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Department for Clinical chemistry and Laboratory Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - M Kiehntopf
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Department for Clinical chemistry and Laboratory Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - U S Schubert
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - M G Clemens
- Department of Biological Sciences and Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - M Bauer
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - A Kortgen
- Department for Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.
- Center for Sepsis and Control and Care, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.
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20
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Sandoval RM, Molitoris BA. Intravital multiphoton microscopy as a tool for studying renal physiology and pathophysiology. Methods 2017; 128:20-32. [PMID: 28733090 DOI: 10.1016/j.ymeth.2017.07.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/12/2017] [Accepted: 07/17/2017] [Indexed: 01/10/2023] Open
Abstract
The kidney is a complex and dynamic organ with over 40 cell types, and tremendous structural and functional diversity. Intravital multi-photon microscopy, development of fluorescent probes and innovative software, have rapidly advanced the study of intracellular and intercellular processes within the kidney. Researchers can quantify the distribution, behavior, and dynamic interactions of up to four labeled chemical probes and proteins simultaneously and repeatedly in four dimensions (time), with subcellular resolution in near real time. Thus, multi-photon microscopy has greatly extended our ability to investigate cell biology intravitally, at cellular and subcellular resolutions. Therefore, the purpose of the chapter is to demonstrate how the use in intravital multi-photon microscopy has advanced the understanding of both the physiology and pathophysiology of the kidney.
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Affiliation(s)
- Ruben M Sandoval
- Indiana University School of Medicine, Roudebush VAMC, Indiana Center for Biological Microscopy, Indianapolis, IN 46202, USA
| | - Bruce A Molitoris
- Indiana University School of Medicine, Roudebush VAMC, Indiana Center for Biological Microscopy, Indianapolis, IN 46202, USA.
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21
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Surgical preparation of rats and mice for intravital microscopic imaging of abdominal organs. Methods 2017; 128:129-138. [PMID: 28698070 DOI: 10.1016/j.ymeth.2017.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/12/2017] [Accepted: 07/04/2017] [Indexed: 01/20/2023] Open
Abstract
Intravital microscopy is a powerful research tool that can provide insight into cellular and subcellular events that take place in organs in the body. However, meaningful results can only be obtained from animals whose physiology is preserved during the process of microscopy. Here I discuss the importance of preserving the overall state of health of the animal, methods of anesthesia, surgical techniques for intravital microscopy of various abdominal organs, methods to maintain and monitor the physiology of the animal during microscopy and associated peri- and post-operative recovery considerations.
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22
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Molitoris BA. Rethinking CKD Evaluation: Should We Be Quantifying Basal or Stimulated GFR to Maximize Precision and Sensitivity? Am J Kidney Dis 2017; 69:675-683. [PMID: 28223001 PMCID: PMC5403623 DOI: 10.1053/j.ajkd.2016.11.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 11/14/2016] [Indexed: 12/20/2022]
Abstract
Chronic kidney disease (CKD) is an increasing clinical problem. Although clinical risk factors and biomarkers for the development and progression of CKD have been identified, there is no commercial surveillance technology to definitively diagnose and quantify the severity and progressive loss of glomerular filtration rate (GFR) in CKD. This has limited the study of potential therapies to late stages of CKD when FDA-registerable events are more likely. Because patient outcomes, including the rate of CKD progression, correlate with disease severity and effective therapy may require early intervention, being able to diagnose and stratify patients by their level of decreased kidney function early on is key for translational progress. In addition, renal reserve, defined as the increase in GFR following stimulation, may improve the quantification of GFR based solely on basal levels. Various groups are developing and characterizing optical measurement techniques using new minimally invasive or noninvasive approaches for quantifying basal and stimulated kidney function. This development has the potential to allow widespread individualization of therapy at an earlier disease stage. Therefore, the purposes of this review are to suggest why quantifying stimulated GFR, by activating renal reserve, may be advantageous in patients and to review fluorescent technologies to deliver patient-specific GFR.
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Affiliation(s)
- Bruce A Molitoris
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indiana Center for Biological Microscopy, Rouderbush VA, Indianapolis, IN.
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23
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Molitoris BA, Reilly ES. Quantifying Glomerular Filtration Rates in Acute Kidney Injury: A Requirement for Translational Success. Semin Nephrol 2017; 36:31-41. [PMID: 27085733 DOI: 10.1016/j.semnephrol.2016.01.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Acute kidney injury (AKI) remains a vexing clinical problem that results in unacceptably high patient mortality, development of chronic kidney disease, and accelerated progression to end-stage kidney disease. Although clinical risks factors for developing AKI have been identified, there is no reasonable surveillance technique to definitively and rapidly diagnose and determine the extent of severity of AKI in any patient. Because patient outcomes correlate with the extent of injury, and effective therapy likely requires early intervention, the ability to rapidly diagnose and stratify patients by their level of kidney injury is paramount for translational progress. Many groups are developing and characterizing optical measurement techniques using novel minimally invasive or noninvasive techniques that can quantify kidney function independent of serum or urinary measurements. The use of both one- and two-compartment models, as well as continuous monitoring, are being developed. This review documents the need for glomerular filtration rate measurement in AKI patients and discusses the approaches being taken to deliver this overdue technique that is necessary to help propel nephrology to individualization of care and therapeutic success.
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Affiliation(s)
- Bruce A Molitoris
- Division of Nephrology, Department of Medicine, Indiana Center for Biological Microscopy, Indiana University School of Medicine, Roudebush VA, Indianapolis, Indiana; FAST BioMedical, Indianapolis, Indiana.
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24
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Hilliard LM, Denton KM. Transcutaneous assessment of glomerular filtration rate in unanesthetized rats using a small animal imager: impact on arterial pressure, heart rate, and activity. Physiol Rep 2016. [PMCID: PMC5064127 DOI: 10.14814/phy2.12723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Lucinda M. Hilliard
- Cardiovascular Program; Monash Biomedicine Discovery Institute and Departments of Physiology; Monash University; Melbourne Victoria 3800 Australia
| | - Kate M. Denton
- Cardiovascular Program; Monash Biomedicine Discovery Institute and Departments of Physiology; Monash University; Melbourne Victoria 3800 Australia
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25
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Improved kinetic model for the transcutaneous measurement of glomerular filtration rate in experimental animals. Kidney Int 2016; 90:1377-1385. [PMID: 27665115 DOI: 10.1016/j.kint.2016.07.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 02/06/2023]
Abstract
Transcutaneous measurement of the glomerular filtration rate (tGFR) is now frequently used in animal studies. tGFR allows consecutive measurements on the same animal, including multiple measurements on a daily basis, because no blood sampling is required. Here we derive and validate a novel kinetic model for the description of transcutaneously measured FITC-Sinistrin excretion kinetics. In contrast to standard 1- to 3-compartment models, our model covers the complete kinetic, including injection and distribution of the tracer in the plasma compartment. Because the model describes the complete progression of the measurement, it allows further refinement by correcting for baseline shifts observed occasionally during measurement. Possible reasons for shifts in the background signal include photo bleaching of the skin, autofluorescence, changes of physiological state of the animals during the measurements, or effects arising from the attachment of the measurement device. Using the new 3-compartment kinetic model with modulated baseline (tGFR3cp.b.m), tGFR measurements in rats can reach comparable precision as those from GFR measurements assessed using a gold standard technique based on constant infusion of a tracer. Moreover, the variability of simultaneous (parallel) measurements, as well as repeated tGFR measurements in the same animals, showed higher precision when tGFR3cp.b.m was compared with the 1-compartment tGFR1cp model.
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26
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Herrera Pérez Z, Weinfurter S, Gretz N. Transcutaneous Assessment of Renal Function in Conscious Rodents. J Vis Exp 2016:e53767. [PMID: 27078159 PMCID: PMC4841314 DOI: 10.3791/53767] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Glomerular filtration rate (GFR) is the gold standard to assess overall kidney function. However, traditional methods to evaluate GFR are cumbersome and time-consuming. In addition, serial blood or urine samples are required, with the associated stress for the experimental animals. A recent technique significantly reduces the investment in time and resources, minimizing the invasiveness and the animal stress, but being equally valid as the traditional approaches. The method measures transcutaneously renal function. Using an optical device and the exogenous renal marker fluorescein isothiocyanate (FITC)-sinistrin, this technique is capable of measuring the elimination kinetics of the marker through the skin. With neither blood nor urine samples nor the associated laboratory assays needed, the results of the transcutaneous measurement are almost instantaneously available. The method has been already validated in different species and successfully applied in several models of renal pathology. Moreover, due to its minimally invasive characteristics, it is suitable for sequential measurements within the same animal. Here is provided a detailed protocol to carry out the transcutaneous assessment of renal function in rodents.
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Affiliation(s)
| | | | - Norbert Gretz
- Medical Research Center, Medical Faculty Mannheim, University of Heidelberg;
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27
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Shmarlouski A, Schock-Kusch D, Shulhevich Y, Buschmann V, Rohlicke T, Herdt D, Radle M, Hesser J, Stsepankou D. A Novel Analysis Technique for Transcutaneous Measurement of Glomerular Filtration Rate With Ultralow Dose Marker Concentrations. IEEE Trans Biomed Eng 2015; 63:1742-50. [PMID: 26595905 DOI: 10.1109/tbme.2015.2501544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE A novel high-precision approach [lifetime-decomposition measurement (LTDM)] for the assessment of the glomerular filtration rate (GFR) based on clearance measurements of exogenous filtration marker. METHODS The time-correlated single photon counting (TCSPC) acquisition in combination with a new decomposition method allows the separation of signal and background from transcutaneous measurements of GFR. RESULTS The performance of LTDM is compared versus the commercially available NIC-kidney patch-based system for transcutaneous GFR measurement. Measurements are performed in awake Sprague Dawley (SD) rats. Using the standard concentration required for the NIC-kidney system [7-mg/100-g body weight (b.w.) FITC-Sinistrin] as reference, the mean difference (bias) of the elimination curves GFR between LTDM and NIC-kidney was 4.8%. On the same animal and same day, the capability of LTDM to measure GFR with a FITC-Sinistrin dose reduced by a factor of 200 (35-μg/100-g b.w.) was tested as well. The mean differences (half lives with low dose using LTDM compared with those using first, the NIC-Kidney system and its standard concentration, and second, LTDM with the same concentration as for the NIC-Kidney system) were 3.4% and 4.5%, respectively. CONCLUSION We demonstrate that with the LTDM strategy substantial reductions in marker concentrations are possible at the same level of accuracy. SIGNIFICANCE LTDM aims to resolve the issue of the currently necessary large doses of fluorescence tracer required for transcutaneous GFR measurement. Due to substantially less influences from autofluorescence and artifacts, the proposed method outperforms other existing techniques for accurate percutaneous organ function measurement.
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28
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Wang JB, Wang HT, Li LP, Yan YC, Wang W, Liu JY, Zhao YT, Gao WS, Zhang MX. Development of a rat model of D-galactosamine/lipopolysaccharide induced hepatorenal syndrome. World J Gastroenterol 2015; 21:9927-9935. [PMID: 26379397 PMCID: PMC4566385 DOI: 10.3748/wjg.v21.i34.9927] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 06/03/2015] [Accepted: 06/26/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To develop a practical and reproducible rat model of hepatorenal syndrome for further study of the pathophysiology of human hepatorenal syndrome.
METHODS: Sprague-Dawley rats were intravenously injected with D-galactosamine and lipopolysaccharide (LPS) via the tail vein to induce fulminant hepatic failure to develop a model of hepatorenal syndrome. Liver and kidney function tests and plasma cytokine levels were measured after D-galactosamine/LPS administration, and hepatic and renal pathology was studied. Glomerular filtration rate was detected in conscious rats using micro-osmotic pump technology with fluorescein isothiocyanate-labelled inulin as a surrogate marker.
RESULTS: Serum levels of biochemical indicators including liver and kidney function indexes and cytokines all significantly changed, especially at 12 h after D-galactosamine/LPS administration [alanine aminotransferase, 3389.5 ± 499.5 IU/L; blood urea nitrogen, 13.9 ± 1.3 mmol/L; Cr, 78.1 ± 2.9 μmol/L; K+, 6.1 ± 0.5 mmol/L; Na+, 130.9 ± 1.9 mmol/L; Cl-, 90.2 ± 1.9 mmol/L; tumor necrosis factor-α, 1699.6 ± 599.1 pg/mL; endothelin-1, 95.9 ± 25.9 pg/mL; P < 0.05 compared with normal saline control group]. Hepatocyte necrosis was aggravated gradually, which was most significant at 12 h after treatment with D-galactosamine/LPS, and was characterized by massive hepatocyte necrosis, while the structures of glomeruli, proximal and distal tubules were normal. Glomerular filtration rate was significantly decreased to 30%-35% of the control group at 12 h after D-galactosamine/LPS administration [Glomerular filtration rate (GFR)1, 0.79 ± 0.11 mL/min; GFR2, 3.58 ± 0.49 mL/min·kgBW-1; GFR3, 0.39 ± 0.99 mL/min·gKW-1]. The decreasing timing of GFR was consistent with that of the presence of hepatocyte necrosis and liver and kidney dysfunction.
CONCLUSION: The joint use of D-galactosamine and LPS can induce liver and kidney dysfunction and decline of glomerular filtration rate in rats which is a successful rat model of hepatorenal syndrome.
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Hall AM, Molitoris BA. Dynamic multiphoton microscopy: focusing light on acute kidney injury. Physiology (Bethesda) 2015; 29:334-42. [PMID: 25180263 DOI: 10.1152/physiol.00010.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Acute kidney injury (AKI) is a major global health problem; much research has been conducted on AKI, and numerous agents have shown benefit in animal studies, but none have translated into treatments. There is, therefore, a pressing unmet need to increase knowledge of the pathophysiology of AKI. Multiphoton microscopy (MPM) provides a tool to non-invasively visualize dynamic events in real time and at high resolution in rodent kidneys, and in this article we review its application to study novel mechanisms and treatments in different forms of AKI.
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Affiliation(s)
- Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; and
| | - Bruce A Molitoris
- Indiana University School of Medicine, Indiana Center for Biological Microscopy, Indianapolis, Indiana
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30
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Measurement of single-kidney glomerular filtration function from magnetic resonance perfusion renography. Eur J Radiol 2015; 84:1419-1423. [PMID: 26032130 DOI: 10.1016/j.ejrad.2015.05.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/27/2015] [Accepted: 05/02/2015] [Indexed: 01/23/2023]
Abstract
Glomerular filtration rate (GFR) describes the flow rate of filtered fluid through the kidney, and is considered to be the reference standard in the evaluation of renal function. There are many ways to test the GFR clinically, such as serum creatinine concentration, blood urea nitrogen and SPECT renography, however, they're all not a good standard to evaluate the early damage of renal function. In recent years, the improvement of MRI hardware and software makes it possible to reveal physiological characteristics such as renal blood flow or GFR by dynamic contrast enhancement magnetic resonance perfusion renography (DEC MRPR). MRPR is a method used to monitor the transit of contrast material, typically a gadolinium chelate, through the renal cortex, the medulla, and the collecting system. This review outlines the basics of DCE MRPR included acquisition of dynamic MR perfusion imaging, calculation of the contrast concentration from signal intensity and compartment models, and some challenges of MRPR method faced in prospective clinical application.
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Munoz-Abraham AS, Judeeba S, Alkukhun A, Alfadda T, Patron-Lozano R, Rodriguez-Davalos MI, Geibel JP. A new method to measure intestinal secretion using fluorescein isothiocyanate-inulin in small bowel of rats. J Surg Res 2015; 197:225-30. [PMID: 25976849 DOI: 10.1016/j.jss.2015.02.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/11/2015] [Accepted: 02/19/2015] [Indexed: 12/17/2022]
Abstract
BACKGROUND Small intestine ischemia can be seen in various conditions such as intestinal transplantation. To further understand the pathologic disruption in ischemia-reperfusion injury, we have developed a method to measure fluid changes in the intestinal lumen of rats. METHODS Two 10-cm rat intestine segments were procured, connected to the terminal apertures of a perfusion device, and continuously infused with 3 mL of HEPES solution (control solution) containing 50 μM of fluorescein isothiocyanate (FITC)-inulin. The perfusion device consists of concentric chambers that contain the perfused bowel segments, which are maintained at 37°C via H₂O bath. The individual chamber has four apertures as follows: two fill and/or drain the surrounding HEPES solution on the blood side of the tissue. The others provide flow of HEPES solution containing FITC-inulin through the lumens. The experimental intestine was infused with the same solution with 100 μM of Forskolin. A pump continuously circulated solutions at 6 mL/min. Samples were collected at 15-min intervals until 150 min and were measured by the nanoflourospectrometer. RESULTS A mean of 6-μM decrease in the FITC-inulin concentration in the Forskolin-treated experimental intestine was observed in comparison with that in the control intestine. The FITC-inulin count dilution in the experimental intestine is a result of an increase of fluid secretion produced by the effect of Forskolin, with P values <0.0001. CONCLUSIONS We demonstrate that it is possible to measure luminal fluid changes over time using our new modified perfusion system along with FITC-inulin to allow real-time determinations of fluid and/or electrolyte movement along the small intestine.
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Affiliation(s)
| | - Sami Judeeba
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut
| | - Abedalrazaq Alkukhun
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut
| | - Tariq Alfadda
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut
| | - Roger Patron-Lozano
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut
| | | | - John P Geibel
- Department of Surgery, Yale University School of Medicine, New Haven, Connecticut.
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Pickering JW, Endre ZH. The definition and detection of acute kidney injury. J Renal Inj Prev 2013; 3:21-5. [PMID: 25340159 PMCID: PMC4206042 DOI: 10.12861/jrip.2014.08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 11/26/2013] [Indexed: 01/23/2023] Open
Abstract
The first consensus definition of Acute Kidney Injury (AKI) was published a decade ago. In this mini narrative review we look at the history of the changes in the definition of AKI and consider how it may change again in the near future. The epidemiology of small changes in creatinine and the difficulties with determining baseline creatinine have driven the changes. Recent evidence on urinary output and the application of structural injury biomarkers are likely to change the definition once more.
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Affiliation(s)
- John W Pickering
- Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand
| | - Zoltán H Endre
- Department of Nephrology, Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
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Benninger RK, Piston DW. Two-photon excitation microscopy for the study of living cells and tissues. CURRENT PROTOCOLS IN CELL BIOLOGY 2013; Chapter 4:4.11.1-4.11.24. [PMID: 23728746 PMCID: PMC4004770 DOI: 10.1002/0471143030.cb0411s59] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Two-photon excitation microscopy is an alternative to confocal microscopy that provides advantages for three-dimensional and deep tissue imaging. This unit will describe the basic physical principles behind two-photon excitation and discuss the advantages and limitations of its use in laser-scanning microscopy. The principal advantages of two-photon microscopy are reduced phototoxicity, increased imaging depth, and the ability to initiate highly localized photochemistry in thick samples. Practical considerations for the application of two-photon microscopy will then be discussed, including recent technological advances. This unit will conclude with some recent applications of two-photon microscopy that highlight the key advantages over confocal microscopy and the types of experiments which would benefit most from its application.
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Fissell WH. Antimicrobial dosing in acute renal replacement. Adv Chronic Kidney Dis 2013; 20:85-93. [PMID: 23265600 DOI: 10.1053/j.ackd.2012.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/11/2012] [Accepted: 10/11/2012] [Indexed: 12/28/2022]
Abstract
Acute kidney injury (AKI) is a common problem in hospitalized patients and is associated with significant morbidity and mortality. Two large trials showed no benefit from increased doses of renal replacement therapy (RRT) despite previous clinical data suggesting that increased clearance from RRT has beneficial effects. Since infection is the leading cause of death in AKI, my group and others hypothesized that increased RRT antibiotic clearance might create a competing morbidity. The data from my group, as well as those of other groups, show that many patients are underdosed when routine "1 size fits all" antibiotic dosing is used in patients with AKI receiving continuous RRT (CRRT). Here, concepts of drug distribution and clearance in AKI are briefly discussed and then 1 antibiotic (piperacillin) is discussed in depth to illustrate the challenges in applying the medical literature to clinical practice. The fact that published data on drug dosing in AKI and dialysis reflect the evolution of practice patterns and often do not apply to present prescribing habits is also discussed. A more general approach to drug dosing facilitates situation-specific prescribing by the nephrologist and critical care specialist.
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Pickering JW, Endre ZH. Challenges facing early detection of acute kidney injury in the critically ill. World J Crit Care Med 2012; 1:61-6. [PMID: 24701403 PMCID: PMC3953865 DOI: 10.5492/wjccm.v1.i3.61] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 10/10/2011] [Accepted: 05/25/2012] [Indexed: 02/06/2023] Open
Abstract
Recent advances in the detection of acute kidney injury (AKI) afford the possibility of early intervention. Proteomics and genomics have identified many markers of tubular cell injury, some of which are manifest in the urine. One trial has used novel injury biomarkers to recruit patients to an intervention prior to an elevation in plasma creatinine. This trial and other recent studies have shown that the use of biomarkers of injury will depend on the time the patient presents following insult to the kidney, the likely cause of that insult, and the pre-injury renal function of that patient. The definition of AKI is likely to change in the near future to include a measure of injury. We anticipate novel therapies becoming available following successful trials that utilize the methodology of early intervention following an elevated injury biomarker.
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Affiliation(s)
- John W Pickering
- John W Pickering, Zoltán H Endre, Christchurch Kidney Research Group, Department of Medicine, University of Otago, Christchurch 8140, New Zealand
| | - Zoltán H Endre
- John W Pickering, Zoltán H Endre, Christchurch Kidney Research Group, Department of Medicine, University of Otago, Christchurch 8140, New Zealand
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36
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Exogenous fluorescent tracer agents based on pegylated pyrazine dyes for real-time point-of-care measurement of glomerular filtration rate. Bioorg Med Chem 2012; 20:2490-7. [PMID: 22459210 DOI: 10.1016/j.bmc.2012.03.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/01/2012] [Accepted: 03/05/2012] [Indexed: 01/23/2023]
Abstract
Novel pyrazine carboxamides bearing hydrophilic poly(ethylene glycol) (PEG) moieties were designed, synthesized, and evaluated for use as fluorescent glomerular filtration rate (GFR) tracer agents. Among these, compounds 4d and 5c that contain about 48 ethylene oxide units in the PEG chain exhibited the most favorable physicochemical and renal clearance properties. In vitro studies show that these two compounds have low plasma protein binding, a necessary condition for renal excretion. In vivo animal model results show that 4d and 5c have a higher urine recovery of the injected dose than iothalamate (a commonly considered gold standard GFR agent). Pharmacokinetic studies show that these two compounds exhibit a plasma clearance equivalent to iothalamate, but with a faster (i.e. lower) terminal half-life than iothalamate (possibly from restricted distribution into the extracellular space due to large molecular size and hydrodynamic volume). Furthermore, the plasma clearance of 4d and 5c remained unchanged upon blockage of the tubular secretion pathway with probenecid, a necessary condition for establishment of clearance via glomerular filtration exclusively. Finally, noninvasive real-time monitoring of this class of compounds was demonstrated by pharmacokinetic clearance of 5c by optical measurements in rat model, which correlates strongly with plasma concentration of the tracer. Hence, 4d and 5c are promising candidates for translation to the clinic as exogenous fluorescent tracer agents in real-time point-of-care monitoring of GFR.
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Choong FX, Sandoval RM, Molitoris BA, Richter-Dahlfors A. Multiphoton microscopy applied for real-time intravital imaging of bacterial infections in vivo. Methods Enzymol 2012; 506:35-61. [PMID: 22341218 PMCID: PMC4136485 DOI: 10.1016/b978-0-12-391856-7.00027-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
To understand the underlying mechanisms of bacterial infections, researchers have for long addressed the molecular interactions occurring when the bacterium interacts with host target cells. In these studies, primarily based on in vitro systems, molecular details have been revealed along with increased knowledge regarding the general infection process. With the recent advancements in in vivo imaging techniques, we are now in a position to bridge a transition from classical minimalistic in vitro approaches to allow infections to be studied in its native complexity-the live organ. Techniques such as multiphoton microscopy (MPM) allow cellular-level visualization of the dynamic infection process in real time within the living host. Studies in which all interplaying factors, such as the influences of the immune, lymphatic, and vascular systems can be accounted for, are likely to provide new insights to our current understanding of the infection process. MPM imaging becomes extra powerful when combined with advanced surgical procedure, allowing studies of the illusive early hours of infection. In this chapter, our intention is to provide a general view on how to design and carry out intravital imaging of a bacterial infection. While exemplifying this using a spatiotemporally well-controlled uropathogenic Escherichia coli (UPEC) infection in rat kidneys, we hope to provide the reader with general considerations that can be adapted to other bacterial infections in organs other than the kidney.
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Affiliation(s)
- Ferdinand X Choong
- Department of Neuroscience, Swedish Medical Nanoscience Center, Karolinska Institutet, Stockholm, Sweden
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Peti-Peterdi J, Burford JL, Hackl MJ. The first decade of using multiphoton microscopy for high-power kidney imaging. Am J Physiol Renal Physiol 2011; 302:F227-33. [PMID: 22031850 DOI: 10.1152/ajprenal.00561.2011] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this review, we highlight the major scientific breakthroughs in kidney research achieved using multiphoton microscopy (MPM) and summarize the milestones in the technological development of kidney MPM during the past 10 years. Since more and more renal laboratories invest in MPM worldwide, we discuss future directions and provide practical, useful tips and examples for the application of this still-emerging optical sectioning technology. Advantages of using MPM in various kidney preparations that range from freshly dissected individual glomeruli or the whole kidney in vitro to MPM of the intact mouse and rat kidney in vivo are reviewed. Potential combinations of MPM with micromanipulation techniques including microperfusion and micropuncture are also included. However, we emphasize the most advanced and complex, quantitative in vivo imaging applications as the ultimate use of MPM since the true mandate of this technology is to look inside intact organs in live animals and humans.
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Affiliation(s)
- János Peti-Peterdi
- Departments of Physiology and Biophysics, and Medicine, Zilkha Neurogenetic Institute, Univ. of Southern California, Los Angeles, CA 90033, USA.
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Camirand G, Li Q, Demetris AJ, Watkins SC, Shlomchik WD, Rothstein DM, Lakkis FG. Multiphoton intravital microscopy of the transplanted mouse kidney. Am J Transplant 2011; 11:2067-74. [PMID: 21834913 DOI: 10.1111/j.1600-6143.2011.03671.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Graft outcomes after kidney transplantation continue to be adversely affected by ischemia-reperfusion injury and rejection. High-resolution, real-time imaging of the transplanted kidney could shed valuable insights into these dynamic processes, but such methodology has not been established. Here we describe a technique for intravital imaging of the transplanted mouse kidney using multiphoton fluorescence microscopy. The technique enabled real-time, high-resolution imaging and quantitation of renal filtration, cell death, leukocyte adhesion and capillary blood flow after transplantation. Using this technique, we found that brief graft ischemia associated with the transplantation procedure led to a rapid decline in renal filtration accompanied by a significant increase in microvascular leakage and renal tubular epithelial cell death within the first 3 h after transplantation. No significant changes in leukocyte adhesion or capillary blood flow were observed during the same time period. This report establishes multiphoton fluorescence microscopy as a sensitive tool for simultaneously studying functional and structural perturbations that occur in the mouse kidney after transplantation and for investigating the migration of leukocytes to the graft.
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Affiliation(s)
- G Camirand
- Surgery Pathology Medicine Immunology, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
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40
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A portable fiberoptic ratiometric fluorescence analyzer provides rapid point-of-care determination of glomerular filtration rate in large animals. Kidney Int 2011; 81:112-7. [PMID: 21881552 DOI: 10.1038/ki.2011.294] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Measurement of the glomerular filtration rate (GFR) is the gold standard for precise assessment of kidney function. A rapid, point-of-care determination of the GFR may provide advantages in the clinical setting over currently available assays. Here we demonstrate a proof of principle for such an approach in a pig and dogs, two species that approximate the vascular access and GFR results expected in humans. In both animal models, a sub-millimeter optical fiber that delivered excitation light and collected fluorescent emissions was inserted into a peripheral vein (dog) or central venous access (pig) by means of commercial intravenous catheters. A mixture of fluorescent chimeras of a small freely filterable reporter and large non-filterable plasma volume marker were infused as a bolus, excited by light-emitting diodes, and the in vivo signals detected and quantified by photomultiplier tubes in both species in less than 60 min. Concurrent standardized 6-h iohexol plasma kidney clearances validated the accuracy of our results for both physiologic and a chronic kidney disease setting. Thus, our ratiometric technique allows for both measurement of plasma vascular volume and highly accurate real-time GFR determinations, enabling clinical decision making in real time.
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41
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Endre ZH, Pickering JW, Walker RJ. Clearance and beyond: the complementary roles of GFR measurement and injury biomarkers in acute kidney injury (AKI). Am J Physiol Renal Physiol 2011; 301:F697-707. [PMID: 21753074 DOI: 10.1152/ajprenal.00448.2010] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Acute kidney injury (AKI) is a common and frequently fatal illness in critically ill patients. The reliance on daily measurements of serum creatinine as a surrogate of glomerular filtration rate (GFR) not only delays diagnosis and development of successful therapies but also hinders insight into the pathophysiology of human AKI. Measurement of GFR under non-steady-state conditions remains an elusive gold standard against which biomarkers of renal injury need to be judged. Approaches to the rapid (near real-time) measurement of GFR are explored. Even if real-time GFR was available, absent baseline information will always limit diagnosis of AKI based on GFR or serum creatinine to a detection of change. Biomarkers of renal cellular injury have provided new strategies to facilitate detection and early intervention in AKI. However, the diagnostic and predictive performance of urinary biomarkers of injury vary, depending on both the time after renal injury and on the preinjury GFR. Progress in understanding the role of each novel biomarker in the causal pathways of AKI promises to enhance their diagnostic potential. We predict that combining rapid measures of GFR with biomarkers of renal injury will yield substantive progress in the treatment of AKI.
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Affiliation(s)
- Zoltán H Endre
- Christchurch Kidney Research Group, Department of Medicine, University of Otago, Christchurch, New Zealand.
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42
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Transcutaneous assessment of renal function in conscious rats with a device for measuring FITC-sinistrin disappearance curves. Kidney Int 2011; 79:1254-8. [DOI: 10.1038/ki.2011.31] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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