Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

Summary

The use of ultra-high field MRI as a non-invasive way to obtain phenotypic information of rodent models for polycystic kidney disease and to monitor interventions is described. Compared with the traditional histological approach, MRI images can be acquired in vivo, allowing for longitudinal follow-up.

Abstract

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular mechanisms responsible for the disease, and are very convenient for rapid drug screening and testing of promising therapies. A limiting factor in these studies is often the lack of efficient non-invasive methods for sequentially analyzing the anatomical and functional changes in the kidney. Magnetic resonance imaging (MRI) is the current gold standard imaging technique to follow autosomal dominant polycystic kidney disease (ADPKD) patients, providing excellent soft tissue contrast and anatomic detail and allowing Total Kidney Volume (TKV) measurements.A major advantage of MRI in rodent models of PKD is the possibility for in vivo imaging allowing for longitudinal studies that use the same animal and therefore reducing the total number of animals required. In this manuscript, we will focus on using Ultra-high field (UHF) MRI to non-invasively acquire in vivo images of rodent models for PKD. The main goal of this work is to introduce the use of MRI as a tool for in vivo phenotypical characterization and drug monitoring in rodent models for PKD.

Introduction

Polycystic Kidney Disease (PKD) includes a group of monogenic disorders characterized by the development of renal cysts. Among them are autosomal-dominant polycystic kidney disease (ADPKD) and autosomal-recessive polycystic kidney disease (ARPKD), which represent the most common types^1,2. ADPKD, the most frequent form of hereditary renal cystic diseases, is originated by mutations in the PKD1 or PKD2 genes. It is characterized by late-onset, multiple bilateral renal cysts, accompanied by variable extra-renal cysts, as well as cardiovascular and muscle skeletal abnormalities. ARPKD, most commonly affecting newborns and young children, is ca....

Protocol

Before starting any procedures with live animals, experimental protocols should be approved by the institutional animal care and use committee (IACUC).

1. Scanner Configuration

1. Before starting, make sure the heater is in OFF position.
2. Select the mini imaging gradient and 38 mm RF coil and mini imaging holder.
3. In the central bore of the holder install the variable temperature assembly.

2. Animal Preparation

1. For MRI experiments, achieve optimal anesthesia using vaporized isoflurane. For induction of anesthesia, place animal in an induction chamber lined with an abs....

Results

In this manuscript, we aim to show the usefulness of UHF MRI as a tool for in vivo phenotypical characterization or drug monitoring in rodent models for PKD and other kidney diseases. All of the experiments were part of experimental protocols approved by the IACUC.

In vivo phenotyping of small rodent models for PKD using UHF MRI:

All imaging studies were performed on live animals under isoflurane anesthesia, with a Bruker AVANCEIII-700 (16.4 T) vertic.......

Discussion

This manuscript shows the feasibility of using UHF MRI as a tool for in vivo phenotypical characterization or drug monitoring in rodent models for PKD.

We describe experiments done at 16.4 T with a wide bore Avance III high resolution NMR spectrometer equipped with micro and mini imaging accessories. The spectrometer was driven by the acquisition and processing software TopSpin2.0PV controlled by Paravision 5.1 imaging software. Because the rodent size varies in longitudinal studies, .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
AVANCEIII-700 (16.4 T)	Bruker	BH067206	Wide-bore two channel multinuclear spectrometer equipped with mini and micro-imaging accessories for in vivo small rodent imaging
TopSpin2.0PV	Bruker	H9088TA2	Spectrometer processing software
Paravision 5.1	Bruker	T10314L5	Imaging sofware
VTU BVT 3000 digital	Bruker	W1101095	Temperature controller