Hypoperfusion of the infrapatellar fat pad and its relationship to MRI T2* relaxation time changes in a 5/6 nephrectomy model

Guo-Shu Huang,Yi-Jen Peng,Chao-Ying Wang,Yue-Cune Chang,Ming-Huang Lin,Ying-Chun Liu,Yi-Chih Hsu,Shih-Wei Chiang,Yu-Juei Hsu,Herng-Sheng Lee

doi:10.1038/s41598-021-89336-8

Abstract

The purpose of present study was to longitudinally investigate the alterations in infrapatellar fat pad (IPFP) vascularity in 5/6 nephrectomized rats by using dynamic contrast enhanced (DCE) MRI and IPFP degeneration by using MRI T2* relaxation time. Twelve male Sprague–Dawley rats were assigned to a control group and a 5/6 nephrectomy CKD group. The right knees of all rats were longitudinally scanned by 4.7 T MRI, and serial changes in the IPFP were assessed at 0, 8, 16, 30, and 44 weeks by DCE-MRI (parameters A, kel and kep) and MRI T2* mapping. After MRI measurements, knee specimens were obtained and evaluated histologically. The CKD group had IPFPs with lower blood volume A and lower permeability kep values from 16 weeks (p < 0.05), lower venous washout kel value from 30 weeks (p < 0.001), and significantly higher T2* values reflecting adipocyte degeneration beginning at 16 weeks (p < 0.05). The histopathological results confirmed the MRI findings. Hypoperfusion and adipocytes degeneration related to CKD were demonstrated in a rodent 5/6 nephrectomy model. DCE parameters and MRI T2* can serve as imaging biomarkers of fat pad degeneration during CKD progression.

Highlights

Chronic kidney disease (CKD) is a progressive condition leading to kidney function impairment and eventually renal failure[1,2]
dynamic contrast enhanced (DCE)-Magnetic resonance imaging (MRI) has been used to study synovial vascularity and inflammation in diseases such as rheumatoid arthritis (RA)[18] and osteoarthritis (OA)[19], but few reports have examined its use to study the pathogenesis of CKD-related OA20
A relationship between hypoperfusion of the infrapatellar fat pad (IPFP) and its degeneration was identified in this animal CKD study

Summary

Introduction

Chronic kidney disease (CKD) is a progressive condition leading to kidney function impairment and eventually renal failure[1,2]. The IPFP is a high vascularity extrasynovial adipose tissue in the knee joint, in close contact with the synovium. It has a network of vessels with numerous anastomoses and is supplied by a network of genicular arteries surrounded by fibrous tissue[10]. DCE-MRI has been used to study synovial vascularity and inflammation in diseases such as rheumatoid arthritis (RA)[18] and osteoarthritis (OA)[19], but few reports have examined its use to study the pathogenesis of CKD-related OA20. DCE-MRI and MRT T2* were used in our study to understand the pathophysiological processes underlying perfusion and compositional changes in IPFP after CKD

Methods

Results

Conclusion