The application of proton nuclear magnetic resonance imaging for the in vivo characterisation of chemically induced renal lesions in rats over a prolonged time study

Glomerular filtration rate (GFR) is an essential parameter of kidney function which can be measured by dynamic contrast enhanced magnetic resonance imaging (MRI-GFR) and transcutaneous approaches based on fluorescent tracer molecules (optical-GFR). In an initial study comparing both techniques in separate measurements on the same animal, the correlation of the obtained GFR was poor. The goal of this study was to investigate if a simultaneous measurement was feasible and if thereby, the discrepancies in MRI-GFR and optical-GFR could be reduced. For the experiments healthy and unilateral nephrectomised (UNX) Sprague Dawley (SD) rats were used. The miniaturized fluorescent sensor was fixed on the depilated back of an anesthetized rat. A bolus of 5 mg/100 g b.w. of FITC-sinistrin was intravenously injected. For dynamic contrast enhanced perfusion imaging (DCE-MRI) a 3D time-resolved angiography with stochastic trajectories (TWIST) sequence was used. By means of a one compartment model the excretion half-life (t1/2) of FITC-sinistrin was calculated and converted into GFR. GFR from DCE-MRI was calculated by fitting pixel-wise a two compartment renal filtration model. Mean cortical GFR and GFR by FITC-sinistrin were compared by Bland-Altman plots and pair-wise t-test. Results show that a simultaneous GFR measurement using both techniques is feasible. Mean optical-GFR was 4.34±2.22 ml/min (healthy SD rats) and 2.34±0.90 ml/min (UNX rats) whereas MRI-GFR was 2.10±0.64 ml/min (SD rats) and 1.17±0.38 ml/min (UNX rats). Differences between healthy and UNX rats were significant (p<0.05) and almost equal percentage difference (46.1% and 44.3%) in mean GFR were assessed with both techniques. Overall mean optical-GFR values were approximately twice as high compared to MRI-GFR values. However, compared to a previous study, our results showed a higher agreement. In conclusion, the possibility to use the transcutaneous method in MRI may have a huge impact in improving and validating MRI methods for GFR assessment in animal models.

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“…1 ). The percentage of cortical volume to total volume was within the range of 73% – 76% as published in the literature [35] , [36] , [37] .…”

Section: Discussionsupporting

confidence: 69%

Simultaneous Measurement of Kidney Function by Dynamic Contrast Enhanced MRI and FITC-Sinistrin Clearance in Rats at 3 Tesla: Initial Results

et al. 2013

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“…This is supported by histological evidence of regeneration of tubular epithelium and return of normal GGT staining in proximal tubules by 21 days after HCBD treatment. This is consistent with magnetic resonance imaging analysis of HCBD-treated rats, which indicated that full recovery of tubular damage occurred within 28 days of treatment (18).…”

Section: Histochemistrysupporting

confidence: 76%

Enhanced Hexachloro-1:3-butadiene Nephrotoxicity in Rats with a Preexisting Adriamycin-Induced Nephrotic Syndrome

Kirby

Bach

1995

Toxicol Pathol

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Renal damage was assessed by histopathology and urinalysis in male Wistar rats treated with either hexachloro-1:3-butadiene (HCBD; a single 170-mg/kg ip dose that caused proximal tubule necrosis), adriamycin (ADR; a single 5-mg/kg ip dose that caused minimal glomerular changes up to 35 days), or HCBD given 2 wk after ADR and compared with age-matched control rats for 21 days. Urinalysis values in ADRtreated rats showed minimal renal changes. HCBD significantly elevated urine volume (10-fold), protein (5-fold), glucose (175-fold), and brush border enzymes (10-600-fold), indicating severe proximal tubular damage, but most parameters returned to pretreatment levels 6 days after treatment. In ADR-pretreated rats subsequently given HCBD, both the urinary alkaline phosphatase and the ratio of kidney : body weight were significantly higher for longer periods. Histopathology demonstrated that the HCBD-induced proximal tubular lesion was confined to the outer stripe of the outer medulla. Advanced regeneration and repair was evident 21 days after HCBD treatment. In the ADR-pretreated rats the HCBD-induced lesion was more severe and affected the entire cortex (24).Statistics. Statistically significant differences between groups were determined by 2-tailed Students' t-test, with p < 0.05 considered to be statistically significant. RESULTS UrinanalysisThere were no significant differences in the urinary parameters in the control and ADR groups ( (Fig. 1 a). Tubules were dilated and filled with homogenous eosinophilic material and necrotic epithelial cells. Signs of regeneration and restitution (i.e., tubular re-epithelialization and loss of tubular casts and debris) were evident by day 7 and complete 21 days after treatment (Fig. 1 b).Histologically, animals in the ADR/HCBD group showed much more extensive renal damage (Fig. 2a) when compared to those treated with HCBD alone (see Fig. 1 a). Extensive tubular damage was present throughout the entire cortex 2 days after HCBD treatment, and tubules were dilated and filled with homogeneous proteinaceous material. Sloughed necrotic calcified epithelial cells were observed in tubular lumens and casts extended deep into the medulla (Fig. 2b). Extensive calcification was evident by day 7 (which was not seen in the HCBD only group) and by day 21, regeneration, although apparent, was less advanced and marked tubular calcification was still evident (Fig. 2c). Table 2 summarizes the differences between the ADR/HCBD group and HCBD alone. HistochemistryControl kidneys demonstrated normal GGT staining of the tubular epithelium of the outer stripe of the outer medulla (Fig. 3a). ADR caused no changes in this staining pattern. GGT staining in the outer stripe of the outer medulla was diminished 24 hr after HCBD treatment, was barely evident by day 3 (Fig. 3b) HCBD is a useful model toxin for damaging the proximal tubule. It is metabolized in the liver, ex-

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Experimental Protocols for MRI Mapping of Renal T1

Garteiser

Bane

Doblas

et al. 2021

Methods in Molecular Biology

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The water proton longitudinal relaxation time, T1, is a common and useful MR parameter in nephrology research. Here we provide three step-by-step T1-mapping protocols suitable for different types of nephrology research. Firstly, we provide a single-slice 2D saturation recovery protocol suitable for studies of global pathology, where whole-kidney coverage is unnecessary. Secondly, we provide an inversion recovery type imaging protocol that may be optimized for specific kidney disease applications. Finally, we also provide imaging protocol for small animal kidney imaging in a clinical scanner.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concept and experimental procedure.

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The application of proton nuclear magnetic resonance imaging for the in vivo characterisation of chemically induced renal lesions in rats over a prolonged time study

Cited by 6 publications

References 8 publications

Simultaneous Measurement of Kidney Function by Dynamic Contrast Enhanced MRI and FITC-Sinistrin Clearance in Rats at 3 Tesla: Initial Results

Simultaneous Measurement of Kidney Function by Dynamic Contrast Enhanced MRI and FITC-Sinistrin Clearance in Rats at 3 Tesla: Initial Results

Enhanced Hexachloro-1:3-butadiene Nephrotoxicity in Rats with a Preexisting Adriamycin-Induced Nephrotic Syndrome

Experimental Protocols for MRI Mapping of Renal T1

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