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Pavlinec JG, Martin M, Donelan W, Kwenda E, Dominguez-Gutierrez P, Bird VG, Canales BK. Initial experience: ex-vivo perfused pig kidney to study urinary oxalate excretion. Urolithiasis 2022; 50:239-247. [PMID: 35294609 DOI: 10.1007/s00240-022-01322-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/03/2022] [Indexed: 11/29/2022]
Abstract
Existing animal models of renal oxalate excretion utilize either gut or peritoneal cavity for oxalate absorption. Ex vivo renal perfusion is an established tool for graft preservation. We sought to repurpose this concept to study the early pathogenesis of urinary lithiasis. Juvenile female Yorkshire porcine kidneys were removed laparoscopically and placed on an ex vivo cardiopulmonary bypass circuit utilizing whole-blood based perfusate. Pre-defined goals were identified for each attempt (n = 5) with plans to increase physiologic model complexity. Tissue perfusion and oxygenation were monitored by serial perfusate iSTAT testing. Once steady urine production was achieved, aqueous oxalate was injected into the perfusate. Renal outcomes were assessed by histology and blood/urinary assays. After demonstrating proof-of-concept in early trials, normothermic (37 °C) ex vivo whole-blood perfusion with Steen Solution™ was performed exceeding three hours at physiologic mean arterial pressures. Circuit parameters remained in the physiologic range for electrolytes, temperature, mean arterial pressure, lactate, and pH. Urine was produced in three experiments. Urinary filtrate demonstrated consistently higher urine creatinine compared to perfusate, and arterial perfusate oxalate boluses lead to urinary oxalate spikes followed by continuous oxalate clearance. Histopathologic analysis with H&E and Pizzolato's method staining demonstrated formation of calcium oxalate crystals. In light of these promising metabolite clearances, ex vivo porcine renal perfusion appears to be a feasible alternative to study oxalate excretion. Longer validation studies are necessary to establish this technique as a model for kidney stone pathogenesis.
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Affiliation(s)
- Jonathan G Pavlinec
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA.,Division of Urology, Department of Surgery, Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, USA
| | - Mark Martin
- Redline Perfusion & Consulting, LLC, Gainesville, FL, USA
| | - William Donelan
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA
| | - Elizabeth Kwenda
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA
| | - Paul Dominguez-Gutierrez
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA
| | - Vincent G Bird
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA.,Division of Urology, Department of Surgery, Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, USA
| | - Benjamin K Canales
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA. .,Division of Urology, Department of Surgery, Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, USA.
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Abstract
PURPOSE OF REVIEW Ultrasonic propulsion is a novel technique that uses short bursts of focused ultrasonic pulses to reposition stones transcutaneously within the renal collecting system and ureter. The purpose of this review is to discuss the initial testing of effectiveness and safety, directions for refinement of technique and technology, and opinions on clinical application. RECENT FINDINGS Preclinical studies with a range of probes, interfaces, and outputs have demonstrated feasibility and consistent safety of ultrasonic propulsion with room for increased outputs and refinement toward specific applications. Ultrasonic propulsion was used painlessly and without adverse events to reposition stones in 14 of 15 human study participants without restrictions on patient size, stone size, or stone location. The initial feasibility study showed applicability in a range of clinically relevant situations, including facilitating passage of residual fragments following ureteroscopy or shock wave lithotripsy, moving a large stone at the ureteropelvic junction with relief of pain, and differentiating large stones from a collection of small fragments. SUMMARY Ultrasonic propulsion shows promise as an office-based system for transcutaneously repositioning kidney stones. Potential applications include facilitating expulsion of residual fragments following ureteroscopy or shock wave lithotripsy, repositioning stones prior to treatment, and repositioning obstructing ureteropelvic junction stones into the kidney to alleviate acute renal colic.
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Affiliation(s)
- Philip C May
- aDepartment of Urology, University of Washington School of Medicine bCenter for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
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Studies using a porcine model: what insights into human calcium oxalate stone formation mechanisms has this model facilitated? Urolithiasis 2016; 45:109-125. [PMID: 27904915 DOI: 10.1007/s00240-016-0947-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/22/2016] [Indexed: 10/20/2022]
Abstract
Animal models are useful in the study of many human diseases. Our current understanding of the biological, physiological, and biochemical aspects of hyperoxaluria and calcium oxalate urolithiasis has been greatly informed by studies using animals. Recently, limitations in the extrapolation to humans of research results derived from laboratory rodents have been identified. The use in biomedical research of a variety of organisms, including large animals, is increasingly encouraged. The purpose of this article is to review the use of pigs in biomedical and stone research, to provide a rationale for using pigs in metabolic stone research, and to describe our 8-year experience in developing a porcine platform for studying hyperoxaluria and calcium oxalate urolithiasis. In this article, we share and review some of the highlights of our findings. We also report results from a recent feeding swine study that demonstrated oxalate-induced renal nephropathy. Finally, we offer ideas for future directions in urolithiasis research using swine.
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Tzou DT, Taguchi K, Chi T, Stoller ML. Animal models of urinary stone disease. Int J Surg 2016; 36:596-606. [PMID: 27840313 DOI: 10.1016/j.ijsu.2016.11.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 11/04/2016] [Accepted: 11/07/2016] [Indexed: 01/29/2023]
Abstract
The etiology of stone disease remains unknown despite the major technological advances in the treatment of urinary calculi. Clinically, urologists have relied on 24-h urine collections for the last 30-40 years to help direct medical therapy in hopes of reducing stone recurrence; yet little progress has been made in preventing stone disease. As such, there is an urgent need to develop reliable animal models to study the pathogenesis of stone formation and to assess novel interventions. A variety of vertebrate and invertebrate models have been used to help understand stone pathogenesis. Genetic knockout and exogenous induction models are described. Surrogates for an endpoint of stone formation have been urinary crystals on histologic examination and/or urinalyses. Other models are able to actually develop true stones. It is through these animal models that real breakthroughs in the management of urinary stone disease will become a reality.
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Affiliation(s)
- David T Tzou
- Department of Urology, University of California, San Francisco, 400 Parnassus Avenue, Suite Box 0738, San Francisco, CA 94143, USA.
| | - Kazumi Taguchi
- Department of Urology, University of California, San Francisco, 400 Parnassus Avenue, Suite Box 0738, San Francisco, CA 94143, USA; Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, Japan.
| | - Thomas Chi
- Department of Urology, University of California, San Francisco, 400 Parnassus Avenue, Suite Box 0738, San Francisco, CA 94143, USA.
| | - Marshall L Stoller
- Department of Urology, University of California, San Francisco, 400 Parnassus Avenue, Suite Box 0738, San Francisco, CA 94143, USA.
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Analysis of altered microRNA expression profiles in the kidney tissues of ethylene glycol-induced hyperoxaluric rats. Mol Med Rep 2016; 14:4650-4658. [PMID: 27748900 PMCID: PMC5102036 DOI: 10.3892/mmr.2016.5833] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 08/26/2016] [Indexed: 11/25/2022] Open
Abstract
Calcium oxalate stones account for >80% of urinary stones, however the mechanisms underlying their formation remains to be elucidated. Hyperoxaluria serves an important role in the pathophysiological process of stone formation. In the present study, differences in the miRNA expression profiles between experimental hyperoxaluric rats and normal rats were analyzed, in order to identify target genes and signaling pathways involved in the pathogenesis of hyperoxaluria. Ethylene glycol and ammonium chloride was fed to male hyperoxaluric rats (EXP) and normal age-matched male rats (CON). The oxalate concentration in the urine of each experimental rat was collected every 24 h and measured on day 14. Three rats exhibiting the highest concentrations were selected for microarray analysis. Microarray analysis was performed to evaluate differences in the expression of microRNA (miRNA) in the kidney tissues from EXP and CON groups, and miRNAs that exhibited a >2-fold or a <0.5-fold alteration in expression between these groups were screened for differential expression patterns according to the threshold P-values. Reverse transcription-quantitative polymerase chain reaction analysis was employed to confirm the microarray results. In order to predict the potential role of miRNAs in pathophysiological processes, gene ontology (GO), pathway and target prediction analyses were conducted. A total of 28 miRNAs were observed to be differentially expressed (>2-fold change) between EXP and CON groups. Among these miRNAs, 20 were upregulated and 8 were downregulated. GO and pathway analyses revealed that the insulin resistance and phosphatidylinositol-bisphosphonate 3-kinase/AKT serine threonine kinase signaling pathways were potentially associated with miRNA regulation in this setting. In conclusion, the results of the present study identified differentially expressed miRNAs in hyperoxaluric rats, and provided a novel perspective for the role of miRNAs in the formation of calcium oxalate stones.
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Bilbault H, Haymann JP. Experimental models of renal calcium stones in rodents. World J Nephrol 2016; 5:189-194. [PMID: 26981444 PMCID: PMC4777791 DOI: 10.5527/wjn.v5.i2.189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/13/2015] [Accepted: 01/04/2016] [Indexed: 02/06/2023] Open
Abstract
In human nephrolithiasis, most stones are containing calcium and are located within urinary cavities; they may contain monohydrate calcium oxalate, dihydrate calcium oxalate and/or calcium phosphates in various proportion. Nephrolithiasis may also be associated with nephrocalcinosis, i.e., crystal depositions in tubular lumen and/or interstitium, an entity which suggests specific pathological processes. Several rodents models have been developed in order to study the pathophysiology of intrarenal crystal formation. We review here calcium rodent models classified upon the presence of nephrolithiasis and/or nephrocalcinosis. As rodents are not prone to nephrolithiasis, models require the induction of a long standing hypercalciuria or hyperoxaluria (thus explaining the very few studies reported), conversely to nephrocalcinosis which may occur within hours or days. Whereas a nephrotoxicity leading to tubular injury and regeneration appears as a critical event for crystal retention in nephrocalcinosis models, surprisingly very little is known about the physiopathology of crystal attachment to urothelium in nephrolithiasis. Creating new models of nephrolithiasis especially in different genetic mice strains appears an important challenge in order to unravel the early mechanisms of urinary stone formation in papilla and fornices.
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