Renal blood perfusion in GK rats using targeted contrast enhanced ultrasonography

Evaluation of melittin-induced acute kidney injury in different degrees in rats by contrast-enhanced ultrasound techniques

To evaluate the renal perfusion of acute kidney injury (AKI) induced by melittin in the rats using contrast-enhanced ultrasound (CEUS). Twenty-four healthy male SD rats were randomly divided into high concentration of melittin group, low concentration of melittin group and control group with 8 rats in each group. Melittin was injected through the rats' right femoral vein, to establish a rat model of AKI. Twelve hours later, CEUS and its Quantitative analysis of TIC parameters was performed. Blood samples from rats were taken to detect creatinine (Cr), right kidney was removed to perform HE staining and apoptosis markers (BAX,Bcl-2,Casepase3) assessment. The correlations among the quantitative parameters of CEUS TIC, Cr and apoptosis marker of PCR were analyzed.Results shows: 1.The quantitative parameters of CEUS TIC(Peak, TP, AUC, MTT) and apoptosis markers PCR parameters (BAX, Bcl-2, Casepase3) were significantly different among three groups (p < 0.01);2. Correlation analysis: Within the high concentration group: There was a correlation among the quantitative parameters of CEUS TIC, cr and apoptosis marker of PCR;In the low concentration group: There was a correlation between the quantitative parameters of CEUS TIC and the parameters of apoptosis marker of PCR, but There was no correlation between Cr and the former two. CEUS can provide a sensitive,real-time,non-invasive technique to detect and evaluate the degree of AKI earlier than Cr.

Quantitative Analysis of Microperfusion in Contrast-Induced Nephropathy Using Contrast-Enhanced Ultrasound: An Animal Study

OBJECTIVE

To investigate imaging biomarkers of microperfusion in contrast-induced nephropathy (CIN) using contrast-enhanced ultrasound (CEUS).

MATERIALS AND METHODS

The CIN model was fabricated by administering indomethacin (10 mg/kg), L-NAME (15 mg/kg), and iopamidol (10 mL/kg) to Sprague-Dawley rats. After 24 hours, CEUS was performed on CIN (n = 6) and control (n = 6) rats with sulphur hexafluoride microbubbles (SonoVue). From time-intensity curves obtained from the kidney arriving time (AT), acceleration time (AC), time to peak (TTP), and peak enhancement (PE) were measured and compared between the groups. After CEUS, the rats were sacrificed, and cell apoptosis markers were evaluated to confirm the development of CIN.

RESULTS

Among CEUS parameters, AT (7.8 ± 1.6 vs. 4.2 ± 0.5 s, p = 0.002), AC (4.7 ± 1.4 vs. 2.0 ± 0.4 s, p = 0.002), and TTP (12.5 ± 2.9 vs. 6.2 ± 0.6 s, p = 0.002) were significantly prolonged in the CIN group compared to controls. PE was significantly higher in the control group than in the CIN group (17.1 ± 1.9 vs. 12.2 ± 2.0 dB, p = 0.004). In kidney tissue, mRNA and protein levels of the apoptotic makers were significantly higher in the CIN group than in the control group (p = 0.003 and p = 0.002).

CONCLUSION

CEUS parameters can be used as imaging biomarkers for microperfusion in CIN. In rats with CIN, AT, AC, and TTP were significantly prolonged, while PE was significantly lower compared to controls.

New Ultrasound Techniques Promise Further Advances in AKI and CKD

AKI and CKD are important clinical problems because they affect many patients and the associated diagnostic and treatment paradigms are imperfect. Ultrasound is a cost-effective, noninvasive, and simple imaging modality that offers a multitude of means to improve the diagnosis, monitoring, and treatment of both AKI and CKD, especially considering recent advances in this technique. Ultrasound alone can attenuate AKI and prevent CKD by stimulating the splenic cholinergic anti-inflammatory pathway. Additionally, microbubble contrast agents are improving the sensitivity and specificity of ultrasound for diagnosing kidney disease, especially when these agents are conjugated to ligand-specific mAbs or peptides, which make the dynamic assessment of disease progression and response to treatment possible. More recently, drug-loaded microbubbles have been developed and the load release by ultrasound exposure has been shown to be a highly specific treatment modality, making the potential applications of ultrasound even more promising. This review focuses on the multiple strategies for using ultrasound with and without microbubble technology for enhancing our understanding of the pathophysiology of AKI and CKD.

Future of the Renal Biopsy: Time to Change the Conventional Modality Using Nanotechnology

At the present time, imaging guided renal biopsy is used to provide diagnoses in most types of primary and secondary renal diseases. It has been claimed that renal biopsy can provide a link between diagnosis of renal disease and its pathological conditions. However, sometimes there is a considerable mismatch between patient renal outcome and pathological findings in renal biopsy. This is the time to address some new diagnostic methods to resolve the insufficiency of conventional percutaneous guided renal biopsy. Nanotechnology is still in its infancy in renal imaging; however, it seems that it is the next step in renal biopsy, providing solutions to the limitations of conventional modalities.