Targeted design of a recombinant tracer for SPECT renal imaging

In Vivo assessment of hypertensive nephrosclerosis using ultrasound localization microscopy

PURPOSE

As a typical chronic kidney disease (CKD), hypertensive nephrosclerosis (HN) is a common syndrome of hypertension, characterized by chronic kidney microvascular damage. Early diagnosis of microvascular damage using conventional ultrasound imaging encounters challenges in sensitivity and specificity owing to the inherent diffraction limit. Ultrasound localization microscopy (ULM) has been developed to obtain microvasculature and microvascular hemodynamics within the kidney, and would be a promising tool for early diagnosis of CKD.

METHODS

In this study, the advantage of quantitative indexes obtained by using ULM (mean arterial blood flow speeds of different segments of interlobular arteries) over indexes obtained using conventional clinical serum (β2-microglobulin, serum urea nitrogen and creatinine) and urine (24-hour urine volume and urine protein) tests and ultrasound Doppler imaging [peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI)] and contrast-enhanced ultrasound imaging [CEUS; rise time (RT), peak intensity (IMAX), mean transit time (mTT) and area under the time-intensity curve (AUC)] for early diagnosis of HN was investigated. Examinations were carried out on 6 spontaneously hypertensive rats (SHR) and 5 normal Wistar-Kyoto (WKY) rats at the age of 10 weeks.

RESULTS

The experimental results showed that the indicators derived from conventional clinical inspections (serum and urine tests) and ultrasound imaging (PSV, EDV, RI, RT, IMAX, mTT and AUC) did not show significant difference between hypertensive and healthy rats (p > 0.05), while the TTP of the SHR group (28.52 ± 5.52 s) derived from CEUS is significantly higher than that of the WKY group (18.68 ± 7.32 s; p < 0.05). The mean blood flow speed in interlobular artery of SHR (12.47 ± 1.06 mm/s) derived from ULM is significantly higher than that of WKY rats (10.13 ± 1.17 mm/s; p < 0.01).

CONCLUSION

The advantages of ULM over conventional clinical inspections and ultrasound imaging methods for early diagnosis of HN were validated. The quantitative results showed that ULM can effectively diagnose HN at the early stage by detecting the blood flow speed changes of interlobular arteries. ULM may promise a reliable technique for early diagnosis of HN in the future. This article is protected by copyright. All rights reserved.

High-performance renal imaging with a radiolabeled, non-excretable chimeric fusion protein

Ideal nuclear imaging tracers should exhibit high target uptake and low background signal. Traditional renal scintigraphy and SPECT scans examine kidney function via static or dynamic tracing of radioactive probes in the kidneys. The lack of tracer affinity to specific biological processes and high background uptake from urinary excretion have added many difficulties to precision renal diagnosis. In this issue of Theranostics, Jin and colleagues innovatively devised a recombinant probe for preferential kidney imaging through targeting of tubular neonatal Fc receptor and proximal tubular basement membrane for sustained tubular reabsorption and accumulation. This work has broad implications regarding how an in depth understanding of physiology and pathology may be of service for tracer development, renal diagnosis, and disease theranostics.