Renal Cortical Blood Perfusion Research Articles

Effect of intrarenal pelvic pressure on pyelo-tubular backflow and renal cortical blood perfusion during mini-percutaneous nephrolithotomy.

To investigate the effects of intrarenal pelvic pressure (IPP) on pyelo-tubular backflow and renal cortical blood perfusion during mini-percutaneous nephrolithotomy (MPCNL). Dynamic changes in pyelo-tubular backflow and renal cortical blood perfusion were studied in six patients undergoing MPCNL using dynamic contrast-enhanced ultrasonography (CEUS) and IPP monitoring. CEUS of intrarenal pelvic perfusion revealed that renal tubules began to exhibit contrast agent reflux when IPP exceeded 34 mmHg during the MPCNL procedure. There was a positive correlation between renal tubule contrast agent reflux and IPP (P < 0.05). Intravenous CEUS of renal cortical blood flow demonstrated that both intrarenal pelvic perfusion time and IPP during MPCNL significantly affected renal cortical blood perfusion. Intrarenal pelvic perfusion time and pressure were negatively correlated with contrast agent peak intensity (PI) and area under the curve (AUC) (P < 0.05). Longer intrarenal pelvic perfusion times and higher pressures resulted in decreased renal cortical blood perfusion. This study directly confirmed through dynamic CEUS and real-time IPP monitoring that an increase in IPP above the threshold of approximately 34 mmHg during MPCNL in patients leads to reflux through the renal tubules and a significant decrease in renal cortical blood perfusion. The safe upper limit for intrarenal pelvic perfusion pressure during MPCNL is approximately 34 mmHg.

Standardized evaluation methodology for renal cortical blood perfusion in elderly patients using contrast‐enhanced ultrasound: A Chinese expert consensus (2024 edition)

AbstractAs a sensitive and non‐invasive method for assessing changes in renal cortical blood perfusion in the elderly, contrast‐enhanced ultrasound (CEUS) can indirectly reflect changes in kidney filtration and reabsorption function, thus providing feasibility for early evaluation of renal function changes. However, significant differences exist among researchers in terms of operational methods, contrast agent selection, post‐data analysis, and many other aspects, leading to substantial heterogeneity in results. This hinders horizontal comparisons and greatly limits the clinical application of contrast‐enhanced ultrasound for evaluating renal cortical blood flow perfusion. Based on the latest domestic and overseas literature and discussions with clinical experts, this consensus provides recommended guidelines for the evaluation of renal cortical blood flow perfusion using contrast‐enhanced ultrasound. It is hoped that this consensus will promote a better understanding of CEUS among medical practitioners at all levels and standardize the examination of renal cortical blood flow perfusion with CEUS.

Transient Receptor Vanilloid Subtype 4-Mediated Ca2+ Influx Promotes Glomerular Endothelial Inflammation in Sepsis-Associated Acute Kidney Injury

Sepsis-associated acute kidney injury (S-AKI) is a frequent complication in patients who are critically ill, which is often initiated by glomerular endothelial cell dysfunction. Although transient receptor vanilloid subtype 4 (TRPV4) ion channels are known to be permeable to Ca2+ and are widely expressed in the kidneys, the role of TRPV4 on glomerular endothelial inflammation in sepsis remains elusive. In the present study, we found that TRPV4 expression in mouse glomerular endothelial cells (MGECs) increased after lipopolysaccharide (LPS) stimulation or cecal ligation and puncture challenge, which increased intracellular Ca2+ in MGECs. Furthermore, the inhibition or knockdown of TRPV4 suppressed LPS-induced phosphorylation and translocation of inflammatory transcription factors NF-κB and IRF-3 in MGECs. Clamping intracellular Ca2+ mimicked LPS-induced responses observed in the absence of TRPV4. In vivo experiments showed that the pharmacologic blockade or knockdown of TRPV4 reduced glomerular endothelial inflammatory responses, increased survival rate, and improved renal function in cecal ligation and puncture-induced sepsis without altering renal cortical blood perfusion. Taken together, our results suggest that TRPV4 promotes glomerular endothelial inflammation in S-AKI and that its inhibition or knockdown alleviates glomerular endothelial inflammation by reducing Ca2+ overload and NF-κB/IRF-3 activation. These findings provide insights that may aid in the development of novel pharmacologic strategies for the treatment of S-AKI.

Correlation of renal cortical blood perfusion and BP response after renal artery stenting.

BackgroundThis study aimed to observe the correlation between renal cortical blood perfusion (CBP) parameters and BP response in patients with severe renal artery stenosis (RAS) who underwent stenting.MethodsThis was a single-center retrospective cohort study. A total of 164 patients with unilateral severe RAS after successful percutaneous transluminal renal artery stenting in Beijing Hospital from October 2017 to December 2020 were included. According to the results of BP evaluated at 12 months, all patients were divided into the BP response group (n = 98) and BP nonresponse group (n = 66). The baseline clinical and imaging characteristics and follow-up data about 24 h ABPM and CBP were recorded and analyzed. Pearson correlation analysis was used to evaluate the relationship between CBP parameters and 24 h average SBP. Univariate and multivariate logistic regression analysis was used to evaluate the risk factors for BP response.ResultsAmong 164 patients with severe RAS, there were 100 males (61.0%), aged 37–75 years, with an average of 56.8 ± 18.4 years, and average artery stenosis of 84.0 ± 12.5%. The BP nonresponse patients had a longer duration of hypertension, more current smoking subjects and diabetic patients, lower eGFR, increased number of hypertensive agents, and rate of insulin compared with the BP response group (P < 0.05). After PTRAS, patients in the BP response group were associated with significantly lower BP and improved CPB, characterized by increased levels of maximum intensity (IMAX), area under ascending curve (AUC1), area under the descending curve (AUC2), shortened rising time (RT), mean transit time (mTT), and prolonged time to peak intensity (TTP; P < 0.05). However, the BP nonresponse group was only associated with significantly reduced RT (P < 0.05) compared with baseline data. During an average follow-up of 11.5 ± 1.7 months, the BP response group was associated with significantly lower levels of SBP, DBP, 24 h average SBP, and 24 h average DBP compared with the nonresponse group (P < 0.05). Pearson correlation analysis showed that the the pre-operative CBP parameters, including IMAX (r = 0.317), RT (r = 0.249), AUC1 (r = 0.614), AUC2 (r = 0.558), and postoperative CBP parameters, including RT (r = 0.283), AUC1 (r = 0.659), and AUC2 (r = 0.674) were significantly positively correlated with the 24 h average SBP, while the postoperative TTP (r = −0.413) and mTT (r = −0.472) were negatively correlated with 24 h average SBP (P < 0.05). Multivariate Logistic regression analysis found that diabetes (OR = 1.294), NT-proBNP (OR = 1.395), number of antihypertensive agents (OR = 2.135), pre-operation IMAX (OR = 1.534), post-operation AUC2 (OR = 2.417), and baseline dDBP (OR = 2.038) were related factors for BP response (all P < 0.05).ConclusionPatients in the BP nonresponse group often have diabetes, a longer duration of hypertension, significantly reduced glomerular filtration rate, and heavier renal artery stenosis. CBP parameters are closely related to 24 h average SBP, and pre-operation IMAX and post-operation AUC2 are markers for a positive BP response.

Dynamic changes of renal cortical blood perfusion before and after percutaneous transluminal renal artery stenting in patients with severe atherosclerotic renal artery stenosis.

Background:This study aims to observe the dynamic changes of renal artery (RA) disease and cortical blood perfusion (CBP) evaluated by contrast-enhanced ultrasound (CEUS) after percutaneous transluminal renal artery stenting (PTRAS) in patients with severe atherosclerotic renal artery stenosis (ARAS) and to analyze the relationship between CBP and prognosis.Methods:This was a single-center retrospective cohort study. A total of 98 patients with unilateral severe ARAS after successful PTRAS in Beijing Hospital from September 2017 to September 2020 were included. According to renal glomerular filtration rate (GFR) detected by radionuclide imaging at 12 months after PTRAS, all patients were divided into the poor prognosis group (n = 21, GFR decreased by ≥20% compared with baseline) and the control group (n = 77, GFR decreased by < 20% or improved compared with baseline). Renal artery stenosis was diagnosed by digital subtraction angiography, and renal CBP was evaluated by CEUS using TomTec Imaging Systems (Germany) before PTRAS, at 6 months and 12 months after discharge. The receiver operating characteristic (ROC) curve with area under the curve (AUC) was used to analyze the predictive value of CBP parameters, including area under ascending curve (AUC1), area under the descending curve (AUC2), rising time (RT), time to peak intensity (TTP), maximum intensity (IMAX), and mean transit time (MTT) for poor prognosis.Results:Among the 98 patients, there were 52 males (53.1%), aged 55–74 years old, with an average age of 62.1 ± 8.7 years, and an average artery stenosis of 82.3 ± 12.9%. The poor prognosis group was associated with significantly increased incidence of diabetes (76.2% vs. 41.6%), and lower levels of GFR of the stenotic kidney (21.8 mL/min vs. 25.0 mL/min) and total GFR (57.6 mL/min vs. 63.7 mL/min) (all P < 0.05), compared with the control group (P < 0.05). In addition, the rate of RA restenosis was significantly higher in the poor prognosis group than in the control group (9.5% vs. 0, χ2 = 9.462, P = 0.002). Compared with the control group, the poor prognosis group was associated with significantly decreased baseline AUC1 and AUC2, and extended duration of TTP and MTT (P < 0.05). At 6 months and 12 months of follow-up, patients in the control group were associated with markedly increased AUC1, AUC2, and IMAX, and shorter duration of RT and MTT (P < 0.05). The ROC curve showed that the predictive values of AUC1, AUC2, RT, TTP, IMAX, and MTT for poor prognosis were 0.812 (95% CI: 0.698–0.945), 0.752 (95% CI: 0.591–0.957), 0.724 (95% CI: 0.569–0.961), 0.720 (95% CI: 0.522–0.993), 0.693 (95% CI: 0.507–0.947), and 0.786 (95% CI: 0.631–0.979), respectively.Conclusions:Preoperative renal CBP in severe ARAS patients with poor prognosis is significantly reduced, and does not show significant improvement after stent treatment over the first year of follow-up. The parameter AUC1 may be a good predictor for renal dysfunction after PTRAS in severe ARAS patients.Trial Registration:ChiCTR.org.cn, ChiCTR1800016252.

Development and Validation of a Prognostic Nomogram for Prognosis in Patients With Renal Artery Stenosis.

Background and ObjectiveRenal artery stenosis (RAS) is associated with an increased risk of renal function deterioration (RFD). Our previous study showed that renal cortical blood perfusion assessed by contrast-enhanced ultrasound (CEUS) was an important related factor for RFD in RAS patients. Based on several conventional related factors confirmed by previous studies, we aimed to establish and verify a CEUS+ scoring system to evaluate the risk of RFD at 1 year of follow-up in RAS patients.MethodsThis study was a single-center retrospective study. A total of 497 elderly RAS patients (247 in the training group and 250 in the verification group) admitted to the Beijing Hospital from January 2016 to December 2019 were included. The baseline characteristics of the patients on admission (including general conditions, previous medical history, blood pressure, blood creatinine, RAS, and cortical blood perfusion in the affected kidney) and renal function [glomerular filtration rate (GFR)] at 1-year of follow-up were collected. We used the univariate and multivariate logistic regressions to establish a CEUS+ scoring system model, the receiver operating characteristic (ROC) curve and area under the curve (AUC) to evaluate prediction accuracy, and the decision curve analysis and nomogram to evaluate the clinical application value of CEUS+ scoring system model.ResultsAmong the 497 patients enrolled, 266 (53.5%) were men, with an average age of (51.7 ± 19.3) years. The baseline clinical-radiomic data of the training group and the verification group were similar (all p > 0.05). Multivariate logistic regression analysis results showed that age [Odds ratio (OR) = 1.937, 95% confidence interval (CI): 1.104–3.397), diabetes (OR = 1.402, 95% CI: 1.015–1.938), blood pressure (OR = 1.575, 95% CI: 1.138–2.182), RAS (OR = 1.771, 95% CI: 1.114–2.816), and area under ascending curve (AUCi) (OR = 2.131, 95% CI: 1.263–3.596) were related factors for the renal function deterioration after 1 year of follow-up (all p < 0.05). The AUC of the ROC curve of the CEUS+ scoring system model of the training group was 0.801, and the Youden index was 0.725 (specificity 0.768, sensitivity 0.813); the AUC of the ROC curve of the validation group was 0.853, Youden index was 0.718 (specificity 0.693, sensitivity 0.835). There was no significant difference in ROC curves between the two groups (D = 1.338, p = 0.325). In addition, the calibration charts of the training and verification groups showed that the calibration curve of the CEUS+ scoring system was close to the standard curve (p = 0.701, p = 0.823, both p > 0.10).ConclusionThe CEUS+ scoring system model is helpful in predicting the risk of worsening renal function in elderly RAS patients.

Clinical and Renal Cortical Blood Perfusion Characteristics in Patients with Severe Atherosclerotic Renal Artery Stenosis Who Underwent Stent Implantation: A Single-center Retrospective Cohort Study

Abstract Objective This study aimed to observe the clinical imaging features of patients with severe atherosclerotic renal artery stenosis (ARAS) receiving stent implantation, and to evaluate the associations between baseline clinical and imaging factors and renal-function deterioration at a 1-year follow-up. Methods This study was a single-center retrospective cohort study. A total of 159 patients with unilateral severe ARAS who underwent stent implantation at Beijing Hospital between July 2017 and December 2020 were consecutively enrolled. According to the renal glomerular filtration rate (GFR), detected by radionuclide renal imaging at 1-year follow-up, all patients were divided into a poor-prognosis group (with a ≥30% decrease in renal GFR; n=32 cases) and a control group (127 cases). Clinical imaging data, including the renal cortical blood perfusion pre- and post-sent implantation, were analyzed. Univariate and multivariate logistic regression analysis was used to evaluate the associations between clinical and imaging factors and renal-function deterioration. Results Of the 159 patients enrolled, 83 (52.2%) were men, with an average age of (57.2±14.7) years. The patient age, rate of diabetes, and systolic blood and diastolic blood pressure in the poor-prognosis group were significantly higher than those in the control group (all P&lt;0.05). Before stent treatment, patients in the poor-prognosis group, compared with the control group, had a significantly smaller area under the ascending curve (AUC1), area under the descending curve (AUC2), and peak intensity (PI), and a longer time to peak intensity (TTP) and mean transit time (MTT) (all P&lt;0.05). After stent treatment, patients in the poor-prognosis group, compared with the control group, showed significantly smaller AUC1, AUC2, and PI, and longer MTT (all P&lt;0.05). Multivariate logistic regression analysis indicated that age (OR=1.251, 95%CI: 1.113–1.406, P=0.0002), diabetes (OR=1.472, 95%CI: 1.110–1.952, P=0.007), systolic blood pressure (OR=1.339, 95%CI: 1.082–1.657, P=0.007), renal GFR (OR=2.025, 95%CI: 1.217–3.369, P=0.006), and AUC1 post-stent (OR=2.173, 95%CI: 1.148–4.113, P=0.017) were the factors associated with renal deterioration at the 1-year follow-up. Conclusions Patients with severe RAS with renal-function deterioration after stent implantation were older, and often had diabetes, hypertension, and impaired renal cortical perfusion. Age, diabetes, systolic blood pressure, renal GFR, and AUC1 after stent implantation were independent factors associated with short-term renal deterioration.

Correlation of Renal Cortical Blood Perfusion and BP Response after Renal Artery Stenting

Correlation of Renal Cortical Blood Perfusion and BP Response after Renal Artery Stenting

The restorative effect of apocynin and catalase in l-arginine induced hypotension on normotensive subjects - the role of oxidative stress.

L-arginine is a substrate for nitric oxide synthase (NOS) responsible for the production of NO. This investigation studied the effect of apocynin, an NADPH oxidase inhibitor and catalase, an H2O2 scavenger on L-arginine induced oxidative stress and hypotension. Forty Wistar-Kyoto rats were treated for 14 days with vehicle, L-arginine (12.5mg/ml p.o.), L-arginine+apocynin (2.5mmol/L p.o.), L-arginine+catalase (10000U/kg/day i.p.) and L-arginine plus apocynin+catalase respectively. Weekly renal functional and hemodynamic parameters were measured and kidneys harvested at the end of the study for histopathological and renal NADPH oxidase 4 (Nox4) assessments. L-arginine administration in normotensive rats decreased systolic blood pressure (120±2 vs 91±2mmHg) and heart rate (298±21 vs 254±15b/min), enhanced urinary output (21.5±4.2 vs 32±1.9ml/24h , increased creatinine clearance (1.72±0.56 vs 2.62±0.40ml/min/kg), and fractional sodium excretion (0.88±0.16 vs 1.18±0.16 %), caused proteinuria (28.10±1.93 vs 35.26±1.69mg/kg/day) and a significant decrease in renal cortical blood perfusion (292±3 vs 258±5bpu) and pulse wave velocity (3.72±0.20 vs 2.84±0.13m/s) (all P<0.05). L-arginine increased plasma malondialdehyde (by ~206 % P<0.05) and NO (by~51 %, P<0.05) but decreased superoxide dismutase (by~31 %, P<0.05) and total antioxidant capacity (by~35 %, P<0.05) compared to control. Renal Nox4 mRNA activity was approximately 2.1 fold higher (P<0.05) in the L-arginine treated rats but was normalized by apocynin and apocynin plus catalase treatment. Administration of apocynin and catalase, but not catalase alone to rats fed L-arginine, restored the deranged renal function and structure, prevented hypotension and enhanced the antioxidant capacity and suppressed Nox4 expression. These findings suggest that apocynin and catalase might be used prophylactically in states of oxidative stress.

The restorative effect of apocynin and catalase in l-arginine induced hypotension on normotensive subjects – the role of oxidative stress

L-arginine is a substrate for nitric oxide synthase (NOS) responsible for the production of NO. This investigation studied the effect of apocynin, an NADPH oxidase inhibitor and catalase, an H2O2 scavenger on L-arginine induced oxidative stress and hypotension. Forty Wistar-Kyoto rats were treated for 14 days with vehicle, L-arginine (12.5mg/ml p.o.), L-arginine+apocynin (2.5mmol/L p.o.), L-arginine+catalase (10000U/kg/day i.p.) and L-arginine plus apocynin+catalase respectively. Weekly renal functional and hemodynamic parameters were measured and kidneys harvested at the end of the study for histopathological and renal NADPH oxidase 4 (Nox4) assessments. L-arginine administration in normotensive rats decreased systolic blood pressure (120±2 vs 91±2mmHg) and heart rate (298±21 vs 254±15b/min), enhanced urinary output (21.5±4.2 vs 32±1.9ml/24h , increased creatinine clearance (1.72±0.56 vs 2.62±0.40ml/min/kg), and fractional sodium excretion (0.88±0.16 vs 1.18±0.16 %), caused proteinuria (28.10±1.93 vs 35.26±1.69mg/kg/day) and a significant decrease in renal cortical blood perfusion (292±3 vs 258±5bpu) and pulse wave velocity (3.72±0.20 vs 2.84±0.13m/s) (all P&lt;0.05). L-arginine increased plasma malondialdehyde (by ~206 % P&lt;0.05) and NO (by ~51 %, P&lt;0.05) but decreased superoxide dismutase (by ~31 %, P&lt;0.05) and total antioxidant capacity (by ~35 %, P&lt;0.05) compared to control. Renal Nox4 mRNA activity was approximately 2.1 fold higher (P&lt;0.05) in the L-arginine treated rats but was normalized by apocynin and apocynin plus catalase treatment. Administration of apocynin and catalase, but not catalase alone to rats fed L-arginine, restored the deranged renal function and structure, prevented hypotension and enhanced the antioxidant capacity and suppressed Nox4 expression. These findings suggest that apocynin and catalase might be used prophylactically in states of oxidative stress.

Contrast-Enhanced Ultrasound Evaluation of Renal Blood Perfusion Changes After Percutaneous Transluminal Renal Angioplasty and Stenting for Severe Atherosclerotic Renal Artery Stenosis

This study used contrast-enhanced ultrasound (CEUS) to evaluate changes in renal cortical blood perfusion after percutaneous transluminal renal angioplasty and stenting (PTRAS) for severe renal artery stenosis (RAS) (≥70%). CEUS was performed in 21 patients with 24 severe RASs that underwent PTRAS. Renal cortical perfusion was quantitatively evaluated by comparing time intensity curve (TIC) parameters for SonoVue (Bracco, Milan, Italy) contrast enhancement, including peak intensity (PI), time to peak (TTP), mean transmit time (MTT), curve ascending slope (S), area under the curve (AUC), AUC-wash-in and AUC-wash-out. The parameters PI, TTP, MTT and S differed significantly between the pre-intervention and post-intervention TIC analysis (p < 0.05). Of the 24 pre-intervention curve appearances, 58.3% (14/24) improved after operation. The PI difference correlated positively with the estimated glomerular filtration rate difference (r = 0.433, p < 0.05). In conclusion, changes in some ultrasound perfusion parameters on CEUS and the shape of the TIC can be used to quantitatively and intuitively evaluate renal cortical blood perfusion change after PTRAS.

Revealing the Decrease of Renal Cortical Perfusion in Primary Glomerular Disease and Renal Aging by Arterial Spin Labeling

Objectives: To reveal the change of renal cortical blood perfusion in primary glomerular disease (PGD) and renal aging by flow-sensitive alternating inversion recovery (FAIR) arterial spin labeling (ASL) technique. Patients and Methods: Renal cortical perfusion was estimated in 24 PGD patients and 30 healthy volunteers using FAIR-ASL in this case-control study. MRI examination was repeated after one week in six randomly selected healthy volunteers. In PGD patients, we regard estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2 as mild PGD and eGFR < 60 mL/min/1.73 m2 as moderate-late PGD. The correlations between ASL perfusion values and eGFR in healthy volunteers, mild and moderate-late PGD patients were assessed. Results: In healthy volunteers, the perfusion values between the twice ASL scanning with one week-interval showed an excellent agreement by Bland-Altman analysis. The mean perfusion value of the bilateral kidneys decreased with age increase (25 - 72 years) (r = -0.496, P = 0.012). There were significant differences in ASL perfusion values among healthy volunteers, mild and moderate-late PGD patients (P < 0.0001). Perfusion values correlated strongly with eGFR in all PGD patients (r = 0.868, P < 0.0001), but not in healthy volunteers (r = 0.156, P = 0.405). The correlation coefficient of perfusion values with eGFR in mild and moderate-late PGD patients were 0.749 (P = 0.008) and 0.809 (P = 0.010), respectively. Conclusion: FAIR-ASL technique represents a feasible approach to monitor the renal perfusion variations in PGD patients. It is a noninvasive technique to discover the early abnormality of renal function, and assess the degree of renal aging.

Characteristics of renal cortical perfusion and its association with renal function among elderly patients with renal artery stenosis

Objective: To evaluate the characteristics of renal cortical blood perfusion assessed by contrast-enhanced ultrasound (CEUS) in elderly patients with renal artery stenosis (RAS) and its relationship with renal function. Methods: Ninety-three elderly patients diagnosed with RAS, who were admitted in Beijing Hospital during June 2017 and December 2018, were retrospectively enrolled. According to the degree of RAS, 186 renal arteries were divided into normal renal artery group (n=79), mild RAS group (30% to 49%, n=59), moderate RAS group (50% to 70%, n=33), and severe RAS group (70% to 99%, n=15). Renal cortical blood perfusion and renal glomerular filtration rate (GFR) were measured by CEUS and radionuclide renal dynamic imaging. According to the renal GFR, 186 kidneys were divided into normal renal function group (GFR≥35 ml/min, n=42) and mild renal insufficiency group (35 ml/min>GFR≥25 ml/min, n=51), moderate renal insufficiency group (25 ml/min>GFR≥15 ml/min, n=75) and severe renal insufficiency group (GFR<15 ml/min, n=18). The renal cortical blood perfusion time-intensity curve (TIC) and related parameters were analyzed, including the area under the curve (AUC), the slope of the ascending branch (A), the peak intensity (PI), the peak time (TTP) and the mean transit time (MTT), the kidneys of different RAS groups and patients with different renal function groups were analyzed. Pearson correlation analysis was used to evaluate the correlation between renal cortical blood perfusion parameters and renal GFR. Results: (1) Renal cortical blood perfusion and GFR: CEUS showed that parameter A of TIC was significantly reduced, while TTP was prolonged in the mild renal artery stenosis group compared with the normal renal artery group (both P<0.05), GFP was similar between the two groups. Cortical perfusion parameters, such as AUC, A, PI and GFR were significantly lower, while TTP and MTT were significantly prolonged in the moderate and severe renal artery stenosis group than in the normal and mild stenosis groups (all P<0.05). Compared with the moderate stenosis group, AUC, A, PI and GFR were significantly lower while TTP, MTT were significantly prolonged in the severe renal artery stenosis group (all P<0.05). (2) TIC showed that the renal perfusion parameters, AUC, PI and A were significantly lower, while TTP was significantly longer in the mild renal dysfunction group than in the normal renal function group (all P<0.001). The changes aggravated in proportion with renal dysfunction. (3) Correlation between perfusion parameters and GFR: Pearson correlation analysis showed that the AUC (r=0.774, P<0.05), A (r=0.815, P<0.05) and PI (r=0.772, P<0.05) were positively correlated with GFR; serum creatinine level (r=-0.841, P<0.05), renal function grading (r=-0.731, P<0.05), TTP (r=-0.803, P<0.05) and MTT (r=-0.741, P<0.05) were negative correlated with GFR. The degree of stenosis was negatively correlated with GFR (r=-0.427, P<0.05). Conclusion: Cortical perfusion parameters differ significantly among patients with various degree of RAS and renal dysfunction. The renal cortical blood perfusion parameters are correlated with renal GFR.

Effect of increased renal pelvis pressure on the kidney of young pigs

Objective To study what impact the elevated intrarenal pelvic pressure (IPP) may have on the childhood kidney. Methods The childhood Guizhou miniature pigs were taken as the subjects and the elevated IPP animal models were established. The IPP pressure was set at levels of 0, 30, 60, 90 mmHg (1 mmHg=0.133 kPa). After the contrast agent was administered intravenously, the left renal cortical microvasculature blood perfusion was measured using contrast-enhanced ultrasonography (CEUS) at each pressure level respectively for 5 minutes. The retrograde pyelography by CEUS was performed at each pressure level for 5 minutes on the same side after the renal cortical microvasculature blood perfusion measurement. Finally the left kidney specimens were sent for pathology. Statistical study was performed on the cortical microvasculature perfusion difference between the various IPP level of 0, 30, 60, 90 mmHg. Results In the 10 repetitions, analysis of variance suggested the Peak intensity (PI) under 4 IPP levels was not all the same statistically (F=58.947, P 0.05); AS for PI, there was statistical difference between the 60 mmHg level and 0 mmHg level (t=5.332, P<0.01). The PI between 0 mmHg level and 90 mmHg level was different statistically (t=10.507, P<0.01). Rank sum test showed that the area under curve (AUC) under four IPP levels was statistically different (χ2=28.876, P<0.01). Compared with AUC under 0 mmHg level, the AUC under 30, 60, 90 mmHg level was statistically different respectively. AS for AUC, there was statistical difference between 0 mmHg and 30 mmHg (Z=-2.497, P<0.05). there was statistical difference between the 60 mmHg level and 0 mmHg level (Z=-2.701, P<0.05). The AUC between 0 mmHg level and 90 mmHg level was different statistically (Z=-2.803, P<0.05). Both the PI and the AUC indicated that the renal blood flow decreased rapidly with the increase of IPP. The retrograde pyelography by CEUS suggested the contrast agent penetrated into the cortex in 60% of subjects, which turned out to be the cortex lacerations in cortex by pathology. The pathology showed fibrin exudation in the Bowman capsule in 70% of specimens. However, all the gross examination for the kidneys suggested no overt rupture. Conclusion Before obvious gross damage emerge the elevated IPP has impacted the kidney microscopically, physiological and pathologically. The hidden injury should be noticed by the clinical staff especially for the young children. Key words: Nephrolith; Intrarenal pelvic pressure; Kidney injury

Clinical value of contrast-enhanced ultrasonography in evaluating renal cortical perfusion in elderly diabetic patients

Objective To investigate the clinical value of contrast-enhanced ultrasonography(CEUS)in evaluating renal cortical perfusion in elderly diabetic patients. Methods A retrospective cross-sectional study was conducted.A total of 70 diabetic patients with chronic renal insufficiency stage 1 to 5 were enrolled.The glomerular filtration rate(GFR)was estimated according to the creatinine level.Based on GFR, patients were divided into a mild-to-moderate chronic kidney disease(CKD)group(n=42, CKD stage 1 to 3)and a severe CKD group(n=28, CKD stage 4 to 5). All patients underwent CEUS for the assessment of renal perfusion and renal dynamic imaging for the assessment of GFR.QLAB analysis software was used to obtain the time-intensity curve(TIC)and related parameters including area under the curve(AUC), the ascending slope(A), the derived peak intensity(DPI)and the time to peak(TTP). The differences in renal perfusion parameters were compared between the two groups.Pearson correlation test was used to assess the correlation between the quantitative parameters of renal cortical perfusion and GFR. Results There was no significant difference in age, gender, history of hypertension, basal blood glucose level, systolic or diastolic blood pressure between the two groups(all P>0.05). CEUS findings revealed high renal cortical blood perfusion in the mild-to-moderate group.There were significant differences in quantitative perfusion parameters including AUC, DPI, A and TTP between the two groups.Pearson correlation test indicated that TTP and A were significantly correlated with GFR in both groups(r=-0.456 and -0.693, 0.432 and -0.529, all P 0.05). Conclusions Diabetic patients with mild-to-moderate CKD have high renal cortical blood perfusion.CEUS findings can indirectly reflect renal function.The perfusion parameters A and TTP have good correlations with GFR.CEUS can be used as a safe and effective method to evaluate renal function, especially in patients with severe renal insufficiency, but more studies are needed to verify the results. Key words: Ultrasonography, inter ventional; Kidney cortex; Renal circulation

The effect of superoxide dismutase enzyme inhibition on renal microcirculation of spontaneously hypertensive-stroke prone and Wistar rats.

A significant factor in the development of hypertension may be excessive vasoconstriction within the renal medulla. This study therefore investigated the role of superoxide dismutase (SOD) in the regulation of renal medullary and cortical blood perfusion (MBP and CBP, respectively) in both stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar rats. CBP and MBP were measured before and after intra-renal infusion of the SOD inhibitor, diethyldithio-carbamic acid (DETC). Under basal conditions, mean arterial pressure was significantly greater in SHRSP than Wistar rats, but both MBP and heart rate (HR) were significantly lower in SHRSP relative to Wistar rats (P<0.05, n=7 in both groups). Infusion of DETC (2 mg/kg/min) into the cortico-medullary border area of the kidney significantly decreased MBP in the SHRSPs (by 28+/-3 %, n=7, P<0.05), indicating a greater vasoconstriction within this vascular bed. However, DETC also significantly decreased MBP in Wistar rats to a similar extent (24+/-4 %, n=7, P<0.05). These results suggest that superoxide anions play a significant role in reducing renal vascular compliance within the renal medulla in both normotensive and hypertensive animals, although the responses are not greater in the hypertensive relative to the control animals.

Chronic administration of apocynin and catalase ameliorates the blood pressure and renal functional parameters attributed by L-NAME induced systemic arterial hypertension in Wistar-Kyoto rats: The role of oxidative stress

Chronic administration of apocynin and catalase ameliorates the blood pressure and renal functional parameters attributed by L-NAME induced systemic arterial hypertension in Wistar-Kyoto rats: The role of oxidative stress

Cystathione gamma lyase/Hydrogen Sulphide Pathway Up Regulation Enhances the Responsiveness of α1A and α1B-Adrenoreceptors in the Kidney of Rats with Left Ventricular Hypertrophy.

The purpose of the present study was to investigate the interaction between H2S and NO (nitric oxide) in the kidney and to evaluate its impact on the functional contribution of α1A and α1B-adrenoreceptors subtypes mediating the renal vasoconstriction in the kidney of rats with left ventricular hypertrophy (LVH). In rats the LVH induction was by isoprenaline administration and caffeine in the drinking water together with intraperitoneal administration of H2S. The responsiveness of α1A and α1B to exogenous noradrenaline, phenylephrine and methoxaminein the absence and presence of 5-methylurapidil (5-MeU) and chloroethylclonidine (CEC) was studied. Cystathione gamma lyase (CSE), cystathione β synthase (CBS), 3-mercaptopyruvate sulphar transferase (3-MST) and endothelial nitric oxide synthase (eNOS) were quantified. There was significant up regulation of CSE and eNOS in the LVH-H2S compared to the LVH group (P<0.05). Baseline renal cortical blood perfusion (RCBP) was increased (P<0.05) in the LVH-H2S compared to the LVH group. The responsiveness of α1A-adrenergic receptors to adrenergic agonists was increased (P<0.05) after administration of low dose 5-Methylurapidil in the LVH-H2S group while α1B-adrenergic receptors responsiveness to adrenergic agonists were increased (P<0.05) by both low and high dose chloroethylclonidine in the LVH-H2S group. Treatment of LVH with H2S resulted in up-regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways in the kidney. These up regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways enhanced the responsiveness of α1A and α1B-adrenoreceptors subtypes to adrenergic agonists in LVH-H2S. These findings indicate an important role for H2S in modulating deranged signalling in the renal vasculature resulting from LVH development.

Up Regulation of cystathione γ lyase and Hydrogen Sulphide in the Myocardium Inhibits the Progression of Isoproterenol-Caffeine Induced Left Ventricular Hypertrophy in Wistar Kyoto Rats.

Hydrogen sulphide (H2S) is an emerging molecule in many cardiovascular complications but its role in left ventricular hypertrophy (LVH) is unknown. The present study explored the effect of exogenous H2S administration in the regression of LVH by modulating oxidative stress, arterial stiffness and expression of cystathione γ lyase (CSE) in the myocardium. Animals were divided into four groups: Control, LVH, Control-H2S and LVH-H2S. LVH was induced by administering isoprenaline (5mg/kg, every 72 hours, S/C) and caffeine in drinking water (62mg/L) for 2 weeks. Intraperitoneal NaHS, 56μM/kg/day for 5 weeks, was given as an H2S donor. Myocardial expression of Cystathione γ lyase (CSE) mRNA was quantified using real time polymerase chain reaction (qPCR).There was a 3 fold reduction in the expression of myocardial CSE mRNA in LVH but it was up regulated by 7 and 4 fold in the Control-H2S and LVH-H2S myocardium, respectively. Systolic blood pressure, mean arterial pressure, pulse wave velocity were reduced (all P<0.05) in LVH-H2S when compared to the LVH group. Heart, LV weight, myocardial thickness were reduced while LV internal diameter was increased (all P<0.05) in the LVH-H2S when compared to the LVH group. Exogenous administration of H2S in LVH increased superoxide dismutase, glutathione and total antioxidant capacity but significantly reduced (all P<0.05) plasma malanodialdehyde in the LVH-H2S compared to the LVH group. The renal cortical blood perfusion increased by 40% in LVH-H2S as compared to the LVH group. Exogenous administration of H2S suppressed the progression of LVH which was associated with an up regulation of myocardial CSE mRNA/ H2S and a reduction in pulse wave velocity with a blunting of systemic hemodynamic. This CSE/H2S pathway exhibits an antihypertrophic role by antagonizing the hypertrophic actions of angiotensin II(Ang II) and noradrenaline (NA) but attenuates oxidative stress and improves pulse wave velocity which helps to suppress LVH. Exogenous administration of H2S augmented the reduced renal cortical blood perfusion in the LVH state.

Downregulation of cystathionine γ lyase and endothelial nitric oxide synthase and reduced responsiveness of α1A adrenergic receptors in the kidneys of left ventricular hypertrophied Wistar Kyoto rats

This article explores the relationship between the renal expression of cystathionine gamma lyase (CSE) and endothelial nitric oxide synthase (eNOS) and the responsiveness of α1A adrenergic receptors in the renal vasculature following left ventricular hypertrophy (LVH) in rats. LVH was established by administering isoprenaline (5 mg/kg, 5 injections subcutaneously, 72 h apart) with 62 mg/L caffeine in drinking water for 2 weeks. Renal vasoconstrictor responses were measured using local administration of adrenergic agonists noradrenaline (NA), phenylephrine (PE), and methoxamine (ME) and the selective α1A adrenergic antagonist 5-methylurapidil (5-MeU). Mean arterial blood pressure was higher (144 ± 9 vs. 116 ± 4 mmHg) and renal cortical blood perfusion was lower in the LVH group (102 ± 5 vs. 157 ± 19 bpu) compared to the control group (P < 0.05). There was a 68% downregulation of mRNA for renal CSE and 79% for eNOS in the LVH group compared to the control group (taken as 100%) (P < 0.05). The high dose of 5-MeU attenuated the vasoconstrictor responses to NA by 33%, PE by 44%, and ME by 43% in the LVH group compared to the same dose in the control group. The reductions in basal renal cortical perfusion and α1A adrenergic receptor vasoconstrictor responses in LVH were associated with the downregulation of the CSE/H2S and eNOS/NO pathways.