ULTRAFINE NANOPARTICLES AS AN IMAGING AGENT FOR DIAGNOSING A RENAL DISORDER

Abstract

The invention relates to a novel use of ultrafine nanoparticles as an imaging agent in a method for diagnosing a renal disorder. The invention also relates to the use of ultrafine nanoparticles as an imaging agent in methods for monitoring the therapeutic efficacy of a renal disorder treatment.

Claims

1. Nanoparticles for diagnosing, in vivo, a renal disorder in human beings or animals, said nanoparticles comprising: (i) a polyorganosiloxane (POS) matrix; (ii) one or more chelating agents grafted onto the POS matrix by SiC covalent bonding; (iii) one or more metal ions chelated by one or more of the chelating agents.

2. The nanoparticles of claim 1, wherein said nanoparticles have an average hydrodynamic diameter of less than 10 nm.

3. The nanoparticles of claim 1, wherein said nanoparticles comprise at least one metal ion for T.sub.1 MRI imaging.

4. The nanoparticles of claim 1, wherein said nanoparticles have a relaxivity (r.sub.1) per particle ranging from 50 to 5000 mM.sup.1.s.sup.1 and/or a weight ratio of metal ion of at least 5%, for example ranging from 5% to 50%.

5. The nanoparticles claim 1, wherein the metal ion is a radioactive metal ion.

6. The nanoparticles of claim 5, wherein the radioactive metal ion is a lanthanide selected from: Dy, Lu, Gd, Ho, Eu, Tb, Nd, Er, Yb and mixtures thereof.

7. The nanoparticles of claim 6, wherein the chelating agent is a lanthanide-complexing agent is selected from: diethylenetriaminepentaacetic acid (DTPA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) efand derivatives thereof.

8. The nanoparticles of claim 1, wherein the metal ion is Gd.sup.3+ and the chelating agent is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA).

9. The nanoparticles of claim 1, further comprising a functionalizing agent selected from: a fluorescent agent, a polyethylene glycol (PEG) and a targeting molecule for targeting the nanoparticles, wherein the functionalizing agent is grafted onto the POS matrix or onto the chelating agent.

10. The nanoparticles of claim 1, wherein the renal disorder is renal fibrosis and/or renal failure.

11. A composition comprising the nanoparticles of claim 1, which composition is intended for use as an imaging agent in the in vivo diagnosis of a renal disorder in human beings or animals.

12. A composition comprising the nanoparticles of claim 1, which composition is intended for use in the diagnosis of a renal disorder in humans or animals.

13. A method for diagnosing a renal disorder in vivo in a human being or an animal to whom the nanoparticles of claim 1 have been administered, the method comprising the steps of (i) capturing one or more images by an appropriate imaging technique in order to visualize said nanoparticles in at least one kidney of the human being or the animal to whom the nanoparticles of claim 1 have been administered; (ii) determining an enhancement of the images; and (iii) comparing the enhancement obtained in step (ii) to a reference enhancement to diagnose the renal disorder in vivo in the human being or the animal.

14. A method for monitoring the therapeutic efficacy of the renal disorder treatment in a human being or an animal to whom the nanoparticles of claim 1 have been administered, said method comprising the steps of: (i) capturing one or more images by an appropriate imaging technique in order to visualize said nanoparticles at least one kidney of the human being or the animal to whom the nanoparticles of claim 1 have been administered, (ii) determining an enhancement of the images; (iii) repeating steps (i) and (ii) during the treatment of the human being or the animal one or more times; (iv) deducing the therapeutic efficacy of the treatment by comparing the change in the enhancement during the treatment.

15. A method for monitoring the therapeutic efficacy of a renal disorder treatment in a human being or an animal, said method comprising the steps of: (i) administering the nanoparticles of claim 1 to the human being or the animal, as an imaging agent, (ii) capturing one or more images by an appropriate imaging technique in order to visualize said nanoparticles in at least one kidney of the human being or the animal; (iii) determining an enhancement of the images; (iv) repeating steps (i) and (iii) during the treatment of the human being or the animal one or more times; (v) deducing the therapeutic efficacy of the treatment by comparing the change in the enhancement during the treatment.

16. The nanoparticles of claim 1, wherein said nanoparticles comprise from 6 to 20 chelating agents.

17. The nanoparticles of claim 2, wherein said average hydrodynamic diameter ranges from 1 to 5 nm.

18. The nanoparticles of claim 4, wherein said weight ratio ranges from 5% to 50%.

19. The nanoparticles of claim 5, wherein said radioactive metal ion is a cation of a radioactive metal ion M.sup.n+, n being an integer ranging from 2 to 4.

Description

FIGURE LEGENDS

[0143] FIG. 1: Diagrammatic representation of a nanoparticle according to the invention. This nanoparticle comprises a polyorganosiloxane matrix onto which are grafted 6 chelating agents of DOTAGA type, 6 chelating agents having chelated Gd3+ gadolinium ions.

[0144] FIG. 2: Image of longitudinal SPECT/CT sections of a male c57Bl/6J mouse 15 minutes after intravenous injection of the nanoparticles obtained according to Example 1 and coupled to indium 111. K corresponds to the kidney; B corresponds to the bladder. These images show that the nanoparticles are eliminated by the kidneys and do not accumulate in the liver.

[0145] FIG. 3: Reflectance fluorescence imaging of female Swiss nude mice before (left) and after (right) the intravenous administration of the nanoparticles obtained according to Example 1 and coupled to a fluorophore of Cy5.5 type. K corresponds to the kidney. These images show that the nanoparticles are eliminated by the kidneys and do not accumulate in the liver.

[0146] FIG. 4: Comparison of the enhancement obtained by MRI after intravenous administration (i) of nanoparticles obtained according to Example 1 or (ii) of DOTAREM nanoparticles in a healthy mouse and in a UUO mouse. The results show that the DOTAREM nanoparticles cannot discriminate between a healthy kidney and a lesioned kidney, whereas a significant difference is obtained with the nanoparticles obtained according to Example 1.

[0147] FIG. 5: Time course of the measurement of the enhancement in the renal cortex by MRI after intravenous administration of DOTAREM nanoparticles (10 mM). The curves obtained show that the enhancement profile is similar between UUO kidney (lesioned kidney) and reference kidney (healthy kidney). The results show that the DOTAREM nanoparticles cannot discriminate between a healthy kidney and a lesioned kidney.

[0148] FIG. 6: Time course of the measurement of the enhancement in the renal cortex by MRI after intravenous administration of nanoparticles obtained according to Example 1 (5 mM). The curves obtained show that the enhancement profile is significantly different between UUO kidney (lesioned kidney) and reference kidney (healthy kidney). The results show that the nanoparticles obtained according to Example 1 can discriminate between a healthy kidney and a lesioned kidney.

[0149] FIG. 7: Images obtained for visualization of nanoparticles obtained according to Example 1 (AGuIX nanoparticles) in the kidneys by LIBS (Laser-Induced Breakdown Spectroscopy). LIBS makes it possible to visualize the gadolinium atoms originating from the AGuIX nanoparticles, represented in green, and the sodium atoms (in red) uniformly distributed in the tissue. The results show that the deficient kidney does not retain the nanoparticles or retains few of said nanoparticles, which is in line with the results obtained by MRI in vivo.

[0150] FIG. 8: Histological images obtained by confocal photon microscopy making it possible to visualize according to the invention grafted with a Cy5.5 chromophore (i.e. AGuIX nanoparticles grafted with a Cy5.5 chromophore, in red) in renal tubular cells. The nanoparticles are accumulated in the renal tubules, a transient step prior to elimination of said nanoparticles.

[0151] FIG. 9: Images obtained by dynamic MRI of the kidneys of a mouse (1 UUO kidney and 1 normal kidney) before and after injection of nanoparticles according to the invention. The results show that the deficient kidney does not retain the nanoparticles according to the invention or retains few of said nanoparticles. Thus, the images show that the enhancement of the renal cortex of the reference kidney is much greater than in the renal cortext of the UUO kidney.

[0152] FIG. 10A: Time course of the measurement of the enhancement in the renal cortex by high time resolution DCE MRI and processing of the data by the Mann-Whitney improved 3TP biostatistics method after intravenous administration of DOTAREM nanoparticles (10 mM). The curves obtained show that the enhancement profile is similar between UUO kidney (lesioned kidney) and reference kidney (healthy kidney). The results show that the DOTAREM nanoparticles cannot discriminate between a healthy kidney and a lesioned kidney.

[0153] FIG. 10B: Time course of the measurement of the enhancement in the renal cortex by high time resolution DCE MRI and processing of the data by the Mann Whitney improved 3TP biostatistics method after intravenous administration of nanoparticles obtained according to Example 1 (5 mM). The curves obtained show that the enhancement profile is significantly different between UUO kidney (lesioned kidney) and reference kidney (healthy kidney). The results show that the nanoparticles obtained according to Example 1 can discriminate between a healthy kidney and a lesioned kidney.

[0154] FIG. 11: Monitoring, by optical imaging, as a function of time, of the AGUIX-Cyanin 5 agent contrast uptake by the lesioned (UUO)kidney compared with the contralateral non-lesioned kidney.

[0155] FIG. 12: Profile of the arterial input function AIF obtained with Dotarem.

[0156] FIG. 13: Profile of the arterial input function AIF obtained with AGUIX.

EXAMPLES

Example 1: Preparation of DOTAGA-Type Nanoparticles

Nanoparticle Synthesis

[0157] A solution was prepared by dissolving 167.3 g of [GdCl.sub.3, 6 H.sub.2O] in 3 l of diethylene glycol (DEG) at ambient temperature. The mixture was then stirred for 3 hours at 140 C. 44.5 ml of 10M sodium hydroxide were then added, then the mixture was heated for 5 hours with stirring at 180 C. in order to obtain solution A. The gadolinium oxide cores obtained in solution A have a hydrodynamic diameter of 1.70.5 nm.

[0158] The polysiloxane layer was obtained by a sol-gel process (i.e. by condensation hydrolysis reactions under basic conditions obtained by adding organosilane precursors). Firstly, a first solution containing 1.6 l of DEG, 51.4 ml of tetraethoxysilane (TEOS) and 80.6 ml of aminopropyltriethoxysilane (APTES) were slowly added (i.e. over the course of 96 hours) to solution A at a temperature of 40 C. One hour after the addition of the first solution, a second solution containing 190 ml of DEG, 43.1 ml of water and 6.9 ml of triethylamine (TEA) was added with stirring for 96 hours at 40 C. At the end of the reaction, the mixture was left to stir for 72 hours at 40 C. and then for 12 hours at ambient temperature in order to obtain solution B. The gadolinium oxide cores covered with polysiloxane of solution B have a hydrodynamic diameter of 2.61.0 nm.

[0159] 163.7 g of anhydrous DOTAGA were then added to solution B. The resulting solution was left to stir for 72 hours at ambient temperature in order to obtain solution C which contains nanoparticles comprising a gadolinium oxide core covered with polysiloxane, onto which nanoparticles DOTAGA groups are grafted.

Purification

[0160] 17.5 l of acetone were added to solution C in order to precipitate the nanoparticles, which were recovered by filtration under vacuum. The nanoparticles were then redispersed in water and placed at pH 2 for 1 hour. The remaining acetone was evaporated off. The nanoparticles were then purified by tangential filtration on a 5 kDa membrane, before the addition of sodium hydroxide so as to obtain a pH of 7.4. Passage through water and purification in water led to the dissolution of the gadolinium oxide core. This dissolution of the gadolinium oxide core is promoted by the presence of the chelating groups grafted onto the polysiloxane matrix of the nanoparticle which complex the gadolinium released by the dissolution of the core. Once the core was dissolved, the polysiloxane shell fragmented into ultrafine nanoparticles consisting of a polysiloxane matrix onto which are grafted DOTAGAs which chelated gadolinium. The solution thus obtained was then filtered twice through a 1.2 m filter and then through a 0.2 m filter in order to remove the bulkiest impurities. The nanoparticles thus obtained have a hydrodynamic diameter of 2.21.0 nm, a longitudinal relaxivity of 11.5 mmol.sup.1.L.s.sup.1 at 60 MHz and at 37 C. Approximately 50 grams of nanoparticles were obtained at the end of the synthesis.

Example 2: Elimination of the Nanoparticles by the Kidney

[0161] LIBS (laser induced breakdown spectroscopy) elemental imaging protocol

[0162] The nanoparticles obtained according to example 1 were administered intravenously to anesthetized mice (8 mg/mouse). Said mice were then sacrificed at 15 min and at 1 h 30 in order to allow the kidneys to be removed.

[0163] The kidneys were perfused and fixed in a 2% glutaraldehyde buffer prepared in a 0.1M sodium cacodylate solution (pH 7.4), overnight at 4 C.

[0164] The kidneys were then rinsed in a 0.2M sodium cacodylate solution (pH 7.4).

[0165] After fixing, the kidneys were dehydrated by means of various ethanol baths of increasing concentration from 30% to 100% of ethanol as follows: 30%, 50%, 70%, 80%, 95%, 100%, 100%, 100%. Each bath lasted 30 min.

[0166] The kidneys were then immersed in a solution of propylene oxide/100% ethanol (1:1) for 30 min, then in 2 propylene oxide baths (each 30 min).

[0167] During the impregnation, the kidneys were immersed in various baths of propylene oxide and of EPON resin for 4 hours overnight according to the ratios (2:1), (1:1), (1:2), (0:1), (0:1).

[0168] The kidneys were then immersed in a mixture of freshly prepared EPON containing the curing agent and placed for study at 56 C. for 72 h.

[0169] The sample can then be prepared for the LIBS analysis by cutting and polishing the surface of the kidney.

[0170] The results are presented in FIGS. 7 and 8.

[0171] Conclusion: the deficient kidney only very slightly retains the nanoparticles, contrary to the functional kidney which retains the nanoparticles.

Example 3: Measurement of the Enhancement in the Kidney by MRI: Comparison Between Nanoparticles According to the Invention (AGuIX Nanoparticles) and the Prior Art Nanoparticles (DOTAREM)

[0172] The images were acquired with a 7T 300 MHz spectrometer imager, equipped with a linear 1H radiofrequency coil dedicated to mice (Bruker, Karlsruhe, Germany).

[0173] The dynamic MRI studies of capture and release of the nanoparticles in the tissues were carried out in vivo and made it possible to determine the change in enhancement in the kidney.

[0174] All the manipulations of the animals were carried out in compliance with the institutional animal protocol guidelines in place at Paris Descartes University, submission CEEA34.JS.142.1 and approved by the Institute's animal research committee, and also the ethics protocols of the company regarding mouse inductions. The relaxivities in solutions were measurement beforehand at 7T in order to prepare the final injection concentration.

[0175] 8-week-old female mice of BalbC/JRJ type (n=6) were UUO-treated at just one kidney, i.e. each mouse comprises one lesioned kidney (UUO kidney) and one healthy kidney (reference kidney). The mice were anesthetized by inhalation of isoflurane (1.5% of air/O2 0.5/ 0.25 l/min) and placed in a dedicated containment cradle. The physiological respiratory parameters were measured throughout the MRI studies using a nonmagnetic respiratory sensor system (the company SAM, US) and the body temperature was maintained by heating the cradle to the core.

[0176] Two solutions were prepared: [0177] Solution according to the invention: 100 l of imaging agent dissolved in a 0.9% saline solution, with a 5 mM concentration of AguIX imaging agent (i.e. the nanoparticles obtained according to Example 1). [0178] Solution according to the prior art: 100 l of imaging agent dissolved in a 0.9% saline solution, with a 10 mM concentration of DOTAREM imaging agent.

[0179] The solutions were administered to mice intravenously via the caudal vein by means of a catheter (specifically developed for nonmagnetic use; calibrated with known dead volume), while the mouse was in the scanner.

[0180] For the reproducibility studies, 100 l of the solution of AGuIX nanoparticles at 5 mM was administered to the 6 mice (the healthy kidney being the reference kidney or ref., and the lesioned kidney being the UUO kidney)

[0181] The original acquisition protocol was developed with the Paravision 5.1 software.

[0182] A dynamic contrast enhanced DCE sequence was recorded using a specific sequence eliminating the free artefacts of movement in post treatment with a TR of 100 ms and a TE of 4 ms and a tilt angle of 80 in order to ensure T1 MRI weighting; a field of view (FOV) of 3 cm3 cm and a final matrix of 256 by 256 points. 4 sections 1 mm thick were chosen, which gives a planar spatial resolution of 117 m117 m. The total time of one acquisition per image was about 3 min 14 sec. Finally, an extended version of the sequence based on the repetition of the previous sequence was used for the dynamic monitoring in order to obtain the same time resolution in a cycle time of from 40 min to 4 h.

[0183] Ater the image acquisition, image processing was carried out by delimiting renal regions of interest in the cortical zones, medulla zones, or the like. The intensities obtained in the cortical zone were reported on an Excel file and the enhancement (S.sub.0S)/S.sub.0 was reported on a graph as a function of time (min) at which the image was acquired. The results are presented in FIGS. 4 to 6 and FIG. 10.

[0184] In the figures, the term SHAM corresponds to a batch of non-UUO mice, of the same genetic background. The term contra UUO corresponds to the non-pathological contralateral kidney of the UUO mice which serves as a healthy kidney reference. In the interests of being rigorous, in order to verify that the contralateral kidney was not undergoing any overcompensation, a batch of non-UUO-induced control mice was studied (SHAM mice), confirming that the results obtained with the SHAM mice kidneys are identical to the results obtained with the UUO contralateral kidney.

[0185] Conclusion: The nanoparticles according to the invention make it possible to significantly differentiate renal functionality between a healthy kidney and an obstructed kidney. DOTAREM does not make it possible to significantly differentiate renal functionality of a healthy kidney and of an obstructed kidney.

Example 4: High Temporal Resolution Perfusion MRI Method for the Characterization of a Pathological Renal Condition: Comparison Between Nanoparticles According to the Invention (AGuIX Nanoparticles) and the Prior Art Nanoparticles (DOTAREM)

[0186] The DCE Dynamic Contrast Enhanced perfusion MRI method conventionally used in MRI imaging of renal function consists in acquiring MRI image kinetics with a temporal resolution of 1 s to 10 s in the literature. It provides kinetic profiles of signal enhancement corresponding to the immediate arrival of the imaging agent in the tissue, in particular for probing the first glomerular pass. These dynamic curves are digitally processed using pharmacokinetic models and provide information regarding the microvascularization, such as blood flows, blood volume fractions, vascular permeability, extracellular volume, etc. However, these results lack reproducibility and require personalized modeling for which there is currently no consensus. Currently, there is ultimately no ideal contrast agent for evaluating renal function. A more appropriate match between the physiological phenomenon of interest and the pharmacokinetic characteristics of the agent must be found. In our case, we propose to develop the high temporal resolution DCE MRI method with the AGuIX agent for improving the diagnosis of a renal disorder on the ureteral obstruction UUO model in mice.

[0187] The UUO model is induced by clamping the right ureter of female BalbC/JRJ mice according to a biochemically characterized protocol from the literature. All the manipulations of the animals were carried out in compliance with the institutional animal protocol guidelines described in Example 3.

[0188] 8-week-old female mice of BalbC/JRJ type (n=6) were UUO-treated at the level of just one kidney, i.e. each mouse comprises one lesioned kidney (UUO kidney) and one healthy kidney (reference kidney). A batch of sham mice makes it possible to verify the validity of the contralateral reference with the MRI method developed. 2 batches of n=6 mice and n=6 shams were studied by dynamic MRI 3 days after induction.

[0189] The DCE MRI acquisition protocol consists in injecting the two types of imaging agents: reference DOTAREM and AGuIX, namely:

[0190] Solution according to the invention: 100 l of imaging agent dissolved in a 0.9% saline solution, with a 5 mM concentration of AGuIX imaging agent.

[0191] Prior art solution: 100 l of imaging agent dissolved in a 0.9% saline solution with 10 mM concentration of DOTAREM imaging agent. [0192] i) The administration protocol is that of Example 3. [0193] ii) The MRI acquisition protocol itself consists in recording sequential images by means of the T1-weighted FLASH MRI sequence (TR=TE=2.2 ms, spatial resolution 117310 m.sup.2), temporal resolution 2.5 s for 10 min with 20 s of precontrast. FIG. 10 shows the enhancement profiles for the 2 agents, in the UUO lesioned kidney and the reference contralateral kidney. T1 mapping in order to verify the concentration of Gd MRI agent is recorded. [0194] iii) The digital processing method derived from method termed 3TP, three time Points, consists in defining 3 main points: basic reference intensity, point of maximum intensity of enhancement, final clearance time, and calculating the slopes of capture and of release of the agent. Next, a Mann-Whitney biostatistical study is applied to the slope parameters calculated for each of the 6 mice, and for each imaging agent.

[0195] Averaged collective method resulting in the value of T1max: [0196] a) Searching for the time T corresponding to the maximum in the overall mean of the DCE MRI intensities. [0197] b) Applying this max to each enhancement profile as Tmax. [0198] c) Taking the mean of 6 enhancement values around the indexed value.

[0199] Conclusion: The diagnosis provided by the high temporal resolution MRI method on the UUO model is better with the AguIX agent since the differential in the impact on the DCE MRI signal linked to the perfusion, between the healthy and pathological kidney condition that can be obtained is substantially greater, the decrease is 350% or a factor of 3.5 with AguiX, whereas it is only 100% or a factor of 2 with DOTAREM. This higher differential obtained with AGuIX enables a better diagnosis of the pathological renal condition with the AGuIX imaging agent.

Example 5: AGuIX Kinetics in Optical Imaging on UUO-Treated Mice

[0200] 8-week-old female mice of BalbC/JRJ type (n=6) were UUO-treated as described in Example 3.

[0201] Solution prepared: 100 l of imaging agent dissolved in a saline solution of sodium chloride at 0.9%, with a 10 mM concentration of AguIX imaging agent coupled to a cyanine 5.5, Cy5.5 fluorophore (AguIX-Cy5.5).

[0202] After anesthesia of the mice by injection of ketamine, a catheter was placed in the tail vein and the agent was injected. The dynamic monitoring was carried out with the Fluobeam camera at the level of the kidney. The wavelengths and the parameters that were used are: excitation 680 nm and emission >700 nm; exposure time: 50 ms; gap between images: 2 sec. The data were processed with ImageJ with an ROI of the same size for all the kidneys then by using the following calculation

enhancement=(RawIntDen(t)RawIntDen(t0))/RawIntDen(t0)

[0203] FIG. 11 represents the kinetics of arrival of the imaging agent in the kidneys for the first five minutes (n=6 kidneys per condition).

[0204] Conclusion: the results obtained confirm the MRI results previously obtained with the AGuIX agent not coupled to cyanine 5.5. The results also show that similar results can be obtained by two different imaging modes with the AGUIX agent comprising the required imaging functionality. It is possible to diagnose the renal UUO pathological condition by also using the in vivo optical imaging in dynamic acquisition method as has been developed in MRI, known to be the quantitative method of reference in perfusion.

Example 6: Diagnosis of a Therapy Against a Dysimmune Pathological Renal Condition by Molecular MRI with AguIX-Monitoring of Therapeutic Efficacy

[0205] MRI model and image processing

[0206] The high temporal resolution DCE perfusion method with a period 2.5 s for 10 min, with injection of the imaging agent as a 100 l bolus at 5 nM (method described in Example 4) was applied on another model of glomerular and tubular renal disorder, i.e. model induced by injection of anti-gbm antibodies in the literature.

[0207] The DCE MRI acquisition protocol consists in injecting the two types of agents: reference DOTAREM or AGuIX, namely:

[0208] solution according to the invention: 100 l of imaging agent dissolved in a 0.9% saline solution, with a 5 mM concentration of AguIX imaging agent, and

[0209] solution according to the prior art: 100 l of imaging agent dissolved in a 0.9% saline solution, with a 10 mM concentration of DOTAREM imaging agent.

[0210] The MRI acquisition protocol itself consists in recording sequential images by means of the T1-weighted FLASH MRI sequence (TR=TE=2.2 ms, spatial resolution 117310 m.sup.2), temporal resolution 2.5 s approximately 120 s with 20 s of precontrast. FIG. 12 shows the enhancement profiles measured on the renal artery on the dynamic images recorded, AIF, for the 2 agents. [0211] i) The data processing corresponds to comparing the ratio of the maximum enhancement between the AIF data from carrier pathological kidneys and pathological kidneys after therapy.

[0212] The glomerular and tubular renal disorder model is obtained by IV injection of Probetex antibody serum PTX-001S in 6-to-8-week old male CBA mice, targeting the glomerular basal membrane and inducing a lesion of the glomerulus, the capsule of which becomes crescent shaped and atrophies, cysts appear, an inflammation and biochemical markers for proteinuria (increase in albumin/creatinine level) and increase of myofibroblasts by alpha SMA assay.

[0213] The therapy was obtained using methyl prednisolone hemisuccinate anti-inflammatory injected intraperitoneally at 25 mg/kg twice a week.

[0214] The imaging was carried out on d7 and d14 post-induction of the pathological condition.

[0215] The pathological model is characterized and diagnosed by the high time resolution DCE perfusion method described in Example 4.

[0216] An additional parameter corresponding to the arrival of the imaging tracer in the organ, i.e. arterial input function AIF, was also recorded. Measured at the input of the organ studied, the AIF itself at the input of the kidney is an indicator of the functionality. The profile is recorded on the anatomical MRI image at the level of the renal arterial point on the dynamic images acquired at DCE high temporal resolution proposed.

[0217] The AIF parameter made it possible in particular to evaluate the monitoring of the efficacy of a therapy.

[0218] Results: FIGS. 12 and 13 show that the efficacy of a therapy diagnosed by in vivo MRI imaging is observed only with the AGuIX agent by measuring the AIF parameter at the kidney input. Specifically, the AIF is identical with DOTAREM between the control mouse (carrier mouse) pool and the mice treated with the anti-gbm antibody (MP mice), whereas it is different, and much higher with the AGuIX agent in the mice treated with the anti-gbm antibody (MP mice).