Renal Resistive Index as a Novel Indicator for Renal Complications in High-Fat Diet-Fed Mice

Abstract

Background/Aims: The renal resistive index (RI) is a novel candidate as a renal injury prognostic indicator, but it remains unclear how renal RI levels correspond to renal injury in diabetic nephropathy. Methods: To examine this issue, we compared 8-week-old male C57BL/6 mice fed with high-fat diet (HFD) versus chow diet (CHD) for 16 weeks. At 8 and 12 weeks, the glomerular filtration rate (GFR), urinary albumin-to-creatinine ratio (UACR), and inflammatory factors (IL-1β, IL-6, TNFα, and MCP-1) were measured, along with the increase in renal RI. Results: Our study suggests RI values positively correlate with GFR for the first 12 weeks of HFD feeding. In contrast, the GFR of 16-week HFD feeding is lower than that of 12-week HFD feeding, whereas RI levels are significantly increased. Additionally, our study suggests RI values accurately indicate the renal fibrosis and renal injury in HFD-fed mice treated with lovastatin. Conclusion: This study seems to confirm the utility of a noninvasive and repeatable ultrasound parameter to rapidly evaluate renal fibrosis in a HFD-induced type 2 diabetic mouse model in vivo. This highly sensitive and comparable renal RI measurement could monitor the whole procedure of disease development in real-time. RI measurement of the renal artery is capable of differentiating responses to standard therapy with lovastatin in HFD-fed mice from the CHD group.

The combination of a neprilysin inhibitor (sacubitril) and angiotensin-II receptor blocker (valsartan) attenuates glomerular and tubular injury in the Zucker Obese rat

“…Interestingly, increased RRI in the diabetic subjects was associated with elevated albuminuria. In fact, the utility of RRI as an indicator of kidney disease was recently validated in high fat diet fed mice [83]. We recently reported increased RRI in db/db mouse, a more severe model of DN, compared to ZO, and this was associated with aortic stiffness and a reduction in renal 3-NTY [34].…”

Renal resistive index as a novel biomarker for cardiovascular and kidney risk reduction in type II diabetes

“…8 Therefore, the kidney is highly susceptible to excess pulsatile flow and of aortic vascular stiffness from the central aorta that can lead to glomerular injury and albuminuria. 9 Its diagnostic utility has been further examined in both acute and chronic settings in clinical practice. 10,11 In this regard, there exists a correlation between RRI and target end-organ CV and kidney damage independent of microalbuminuria in hypertensive patients (Figure 1).…”

“…These processes are especially deleterious to high flow, low impedance circulatory beds such as the kidney microcirculation . Therefore, the kidney is highly susceptible to excess pulsatile flow and of aortic vascular stiffness from the central aorta that can lead to glomerular injury and albuminuria . Its diagnostic utility has been further examined in both acute and chronic settings in clinical practice .…”

Pulsatility Index as a Novel Parameter for Perfusion in Mouse Model of Hindlimb Ischemia

“…Conventional noninvasive in vivo methods for assessing blood flow recovery are used for physiological investigations but are not reproducible, which prevents comparisons. The current imaging techniques, such as laser Doppler imaging [11], contrast-enhanced power Doppler ultrasound imaging, pulsedwave velocity ultrasound [12,13], magnetic resonance imaging (MRI) [14], computed tomography (CT) [15], single-photon emission computed tomography (SPECT) [16], and positron emission tomography (PET) [17], are hampered due to compromises between spatial and temporal resolution, penetration, and sensitivity. These methods might be unsuitable for small animals, or they may be unstable for measurement because of external factors, including environment, light, and room temperature, and interior factors including body temperature, body gestures, etc.…”

“…These methods might be unsuitable for small animals, or they may be unstable for measurement because of external factors, including environment, light, and room temperature, and interior factors including body temperature, body gestures, etc. Furthermore, the application of these imaging methods in small animal models, especially mice, is time-intensive and requires extensive use of expensive equipment as well as expertise [12]. Some imaging methods are invasive and irreproducible [18].…”