Kidney transplantation has saved many lives since the first successful transplant more than 50 years ago. Although advances in surgical technique and immunosuppressive therapy have resulted in 1-year survival rates greater than 90%. graft dysfunction in the early post-transplant period occurs in up to 30% of transplant recipients. This is an important factor in the ultimate fate of the allograft, as acute rejection in those recipients with delayed graft function results in a 5-year graft survival of only 35%. This observation alone suggests that early diagnosis of acute rejection episodes is imperative if we are to limit nephron loss and maintain allograph function. Magnetic Resonance Imaging (MRI) is well-suited for assessing renal transplant anatomy and function. MRI uses non-nephrotoxic contrast agents and has the spatial resolution to independently assess different anatomical regions. New MR techniques, termed functional MRI, can assess the filtration capacity of glomeruli, regional blood flow within the kidney, and the oxygen bioavailability at the tissue level. To date, no other modality can combine techniques to provide such a comprehensive evaluation of the kidney. If MRI can non-invasively identify the underlying cause of dysfunction, we could potentially avoid biopsy and still target therapy appropriately. The R21 phase of this proposal focuses on optimizing MR perfusion, blood oxygen level dependent (BOLD) MRI, and single kidney filtration rate (skGFR) sequences. Repetitive measurements of MR perfusion, BOLD MRI and skGFR will be performed on adult volunteers in order to determine their reproducibility and natural variability. If successful, this proposal will result in a non-invasive method for evaluating kidney function, which then can be applied to the study of transplanted kidney dysfunction. The R33 phase of this proposal will utilize MR perfusion, BOLD MRI and skGFR in the differentiation of acute rejection from ATN in a population with delayed graft function. In addition to using functional MRI in the diagnosis of transplant dysfunction, we will streamline image analysis to reduce post-processing time and allow widespread clinical application of our techniques. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21DK070243-02
Application #
7230004
Study Section
Special Emphasis Panel (ZDK1-GRB-7 (O3))
Program Officer
Flessner, Michael Francis
Project Start
2006-05-01
Project End
2009-04-30
Budget Start
2007-05-01
Budget End
2009-04-30
Support Year
2
Fiscal Year
2007
Total Cost
$179,853
Indirect Cost
Name
University of Wisconsin Madison
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Marquez, Eva; Sadowski, Elizabeth; Reese, Shannon et al. (2012) Serum HSP27 is associated with medullary perfusion in kidney allografts. J Nephrol 25:1075-80
Huang, Yin; Sadowski, Elizabeth A; Artz, Nathan S et al. (2011) Measurement and comparison of T1 relaxation times in native and transplanted kidney cortex and medulla. J Magn Reson Imaging 33:1241-7
Artz, Nathan S; Sadowski, Elizabeth A; Wentland, Andrew L et al. (2011) Reproducibility of renal perfusion MR imaging in native and transplanted kidneys using non-contrast arterial spin labeling. J Magn Reson Imaging 33:1414-21
Artz, Nathan S; Wentland, Andrew L; Sadowski, Elizabeth A et al. (2011) Comparing kidney perfusion using noncontrast arterial spin labeling MRI and microsphere methods in an interventional swine model. Invest Radiol 46:124-31
Dahlberg, Rebecca; Muth, Brenda; Samaniego, Milagros et al. (2010) One-year serum albumin is an independent predictor of outcomes in kidney transplant recipients. J Ren Nutr 20:392-7
Djamali, Arjang; Vidyasagar, Aparna; Yagci, Gokhan et al. (2010) Mycophenolic acid may delay allograft fibrosis by inhibiting transforming growth factor-beta1-induced activation of Nox-2 through the nuclear factor-kappaB pathway. Transplantation 90:387-93
Djamali, Arjang; Sadowski, Elizabeth A; Muehrer, Rebecca J et al. (2007) BOLD-MRI assessment of intrarenal oxygenation and oxidative stress in patients with chronic kidney allograft dysfunction. Am J Physiol Renal Physiol 292:F513-22