Intrarenal hemodynamic changes after captopril test in patients with type 2 diabetes: a duplex Doppler sonography study

Early changes in pulmonary function and intrarenal haemodynamics and the correlation between these sets of parameters in patients with T2DM

PURPOSE

The main objectives of this study were to assess the early changes in pulmonary function and intrarenal haemodynamics and to determine the correlation between pulmonary function and intrarenal haemodynamics in patients with type 2 diabetes mellitus (T2DM).

METHODS

96 patients with T2DM (diabetes group) without diabetes kidney disease (DKD) and 33 healthy subjects (control group) were enrolled in studies intended to assess the early changes in pulmonary function and intrarenal haemodynamics associated with diabetes, as well as to determine the correlation between pulmonary function and intrarenal haemodynamics.

RESULTS

Pulmonary functional parameters were negatively correlated with HbA1c levels and diabetes duration (P< 0.05). Moreover, renal functional parameters were positively correlated with HbA1c levels and diabetes duration (P<0.05). Additionally, pulmonary functional parameters were negatively correlated with renal functional parameters (P<0.05). Multiple linear regression analysis of the relationship between pulmonary functional parameters and the bilateral kidney arterial resistivity index (RI) showed that all the pulmonary functional parameters were significantly correlated with the arterial RI (P< 0.05).

CONCLUSIONS

Patients displayed changes in pulmonary function and intrarenal haemodynamics during the preclinical stages of DKD. Regulating glycaemia may improve intrarenal haemodynamics in the bilateral interlobular renal arteries. Moreover, during the preclinical stages of DKD, the right kidney RI is a effective predictor of early changes in pulmonary function in adult T2DM patients.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02798198); registered 8 June 2016.

Longitudinal follow-up study of the retrobulbar and intrarenal hemodynamics in patients with T2DM

OBJECTIVE

The primary aim of this study is to examine the hemodynamics of retrobulbar and intrarenal in the changes of early stage of type 2 diabetes mellitus (T2DM) patients from 2000 to 2015 and to assess incidence associated with diabetic kidney disease (DKD) and diabetic retinopathy (DR).

METHOD

Our study contained 60 subjects newly diagnosed of T2DM were divided into 2 groups base on the mean resistive index (RI) (≤0.7 and >0.7) of hemodynamic and to compare between-group differences of the early changes in hemodynamics of retrobulbar and intrarenal and also to conclude the incidences of diabetic kidney disease (DKD) and diabetic retinopathy (DR)subsequently with a long follow-up duration(2000-2015). First, to compare the mean RI of central retinal artery (CRA) between 2 groups. Second, to compare the mean RI of intrarenal hemodynamics in the bilateral interlobular renal arteries, renal function parameters (blood urea nitrogen (BUN), creatinine (Cr), blood glucose parameters (glycosylated hemoglobinA1c (HbA1c), fasting plasma glucose (FBG), and 2-hour postprandial blood glucose (2hPBG)), glomerular filtration rate (GFR), albumin excretion rate (AER), and urine albumin-to-creatinine ratio (UACR) between 2 groups.

RESULTS

First part of our follow-up studies was to compare hemodynamic RI index of retrobulbar in years of 2000 and 2015, both renal function and blood glucose parameters were fund significantly enhanced in subject group RIs ≤0.7. Incidence of DKD and DR was notably lower in group RIs ≤0.7 than group RIs > 0.7, difference was statistically significant (P < .05). Incidence of HbA1c ≤7% was higher in group RIs ≤0.7 than group RIs >0.7, but difference was not statistically significant (P > .05). Incidence of proliferative diabetic retinopathy (PDR) was notably lower in group RIs ≤0.7 than group RIs >0.7, but the difference was not statistically significant (P > .05). Second part of our follow-up studies was to compare hemodynamic RI index of interlobular renal in years of 2000 and 2015, both renal function and blood glucose parameters were fund significantly enhanced in subject group RIs ≤0.7. Compared data of various incidences from first part of study were coherent with second part. (Incidence of DKD and DR was notably lower in group RIs ≤0.7 than group RIs >0.7, difference was statistically significant (P < .05). Incidence of HbA1c ≤7% was higher in group RIs ≤0.7 than group RIs >0.7, but difference was not statistically significant (P > .05). Incidence of PDR was notably lower in group RIs ≤0.7 than group RIs >0.7, but the difference was not statistically significant (P > .05).

CONCLUSIONS

RIs of retrobulbar and interlobular renal which would serve as a good predictors for the hemodynamics changes in retrobulbar and intrarenal would assess incidence of DKD and DR during the preclinical stage in long-term range excluding renal function and HbA1c in T2DM patients.

Traditional Thermal Therapy with Indirect Moxibustion Decreases Renal Arterial Resistive Index in Patients with Chronic Kidney Disease

OBJECTIVE

To evaluate the immediate effects of traditional local thermal therapy with indirect moxibustion on renal hemodynamics in patients with chronic kidney disease (CKD) by using Doppler ultrasonography (US).

DESIGN

Examiner-blinded crossover study.

PARTICIPANTS

Forty-three participants with CKD (mean age ± standard deviation [SD], 44 ± 15 years; estimated glomerular filtration rate, 69.5 ± 25.5 mL/min per 1.73 m(2); 20 men and 23 women).

INTERVENTION

Participants received three successive treatment sessions of indirect moxibustion bilaterally at BL 23, a crucial acupuncture point, in the session. In the control session, the examiner was blinded by using smoke and aroma produced by moxibustion performed in an ashtray placed near the patient's body.

OUTCOME MEASURES

The main outcome measure was resistive index (RI) in the renal segmental arteries. Blood flow parameters, including RI, were measured for six renal segmental arteries by using Doppler US at rest (baseline), immediately after completion of moxibustion (post 1), and 10 minutes later (post 2). Adverse events were monitored during intervention.

RESULTS

In the control session, RI at post 1 (median [first, third quartile]: 0.587 [0.562, 0.626]) and post 2 (0.583 [0.567, 0.629]) did not change significantly compared with baseline (0.592 [0.563, 0.636]), while in the treatment session, RI at post 1 (0.565 [0.530, 0.618]) and post 2 (0.561 [0.533, 0.614]) decreased significantly compared with baseline (0.590 [0.550, 0.652]) (p < 0.001 and p < 0.001, respectively). The reduction in RI from baseline to post 2 in treatment session was significantly greater than in control session (mean ± SD, -0.026 ± 0.028 versus -0.003 ± 0.028; mean difference, -0.023 [95% confidence interval, -0.036 to -0.010]; p = 0.001]. No adverse events, such as burns, were observed during the study period.

CONCLUSION

Renal vascular resistance was decreased after indirect moxibustion therapy in patients with CKD.

Dual renin-angiotensin system inhibition for prevention of renal and cardiovascular events: do the latest trials challenge existing evidence?

Circulatory and tissue renin-angiotensin systems (RAS) play a central role in cardiovascular (CV) and renal pathophysiology, making RAS inhibition a logical therapeutic approach in the prevention of CV and renal disease in patients with hypertension. The cardio- and renoprotective effects observed with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) monotherapy, together with the availability of a direct renin inhibitor (DRI), led to the investigation of the potential benefits of dual RAS inhibition. In small studies, ARB and ACE inhibitor combinations were shown to be beneficial in patients with CV or renal disease, with improvement in surrogate markers. However, in larger outcome trials, involving combinations of ACE inhibitors, ARBs or DRIs, dual RAS inhibition did not show reduction in mortality in patients with diabetes, heart failure, coronary heart disease or after myocardial infarction, and was in fact, associated with increased harm. A recent meta-analysis of all major trials conducted over the past 22 years involving dual RAS inhibition has clearly shown that the risk-benefit ratio argues against the use of dual RAS inhibition. Hence, the recent evidence clearly advocates against the use of dual RAS inhibition, and single RAS inhibition appears to be the most suitable approach to controlling blood pressure and improving patient outcomes.

Renal hemodynamics and renal function after catheter-based renal sympathetic denervation in patients with resistant hypertension

Increased renal resistive index and urinary albumin excretion are markers of hypertensive end-organ damage and renal vasoconstriction involving increased sympathetic activity. Catheter-based sympathetic renal denervation (RD) offers a new approach to reduce renal sympathetic activity and blood pressure in resistant hypertension. The influence of RD on renal hemodynamics, renal function, and urinary albumin excretion has not been studied. One hundred consecutive patients with resistant hypertension were included in the study; 88 underwent interventional RD and 12 served as controls. Systolic, diastolic, and pulse pressure, as well renal resistive index in interlobar arteries, renal function, and urinary albumin excretion, were measured before and at 3 and 6 months of follow-up. RD reduced systolic, diastolic, and pulse pressure at 3 and 6 months by 22.7/26.6 mm Hg, 7.7/9.7 mm Hg, and 15.1/17.5 mm Hg (P for all <0.001), respectively, without significant changes in the control group. SBP reduction after 6 months correlated with SBP baseline values (r=-0.46; P<0.001). There were no renal artery stenoses, dissections, or aneurysms during 6 months of follow-up. Renal resistive index decreased from 0.691±0.01 at baseline to 0.674±0.01 and 0.670±0.01 (P=0.037/0.017) at 3- and 6-month follow-up. Mean cystatin C glomerular filtration rate and urinary albumin excretion remained unchanged after RD; however, the number of patients with microalbuminuria or macroalbuminuria decreased. RD reduced blood pressure, renal resistive index, and incidence of albuminuria without adversely affecting glomerular filtration rate or renal artery structure within 6 months and appears to be a safe and effective therapeutic approach to lower blood pressure in patients with resistant hypertension.

New approaches for the evaluation of renal vascular function in diabetes

In this issue of Diabetologia, two new approaches are described for the assessment of intra-renal blood flow in people with diabetes. The first approach used the technique of dynamic assessment of the resistance index (RI) in the renal interlobar arteries before and after administration of sublingual glyceryl trinitrate, and the second used MRI to assess total renal blood flow in relation to mean arterial pressure, thereby enabling direct measurement of overall renal RI. The results of the first study raise the possibility that dynamic evaluation of the intra-renal RI could be used as an early detector of vascular alterations in type 2 diabetes, before the onset of microalbuminuria. The results of the second study suggest that decreases in renal blood flow in people with longstanding type 1 diabetes reflect intra-renal vascular stiffening and raise the possibility that in microalbuminuric patients it may also reflect increased intraglomerular pressure.

Renal autoregulation in medical therapy of renovascular hypertension

INTRODUCTION

Renovascular hypertension (RVH) is caused by renal ischaemia associated with haemodynamically significant renal artery stenosis (RAS). The choice of optimal treatment of atherosclerotic RAS is still controversial. Increase in the renal resistive index (RI) value after captopril administration is considered to indicate preserved renal autoregulation. The objective of the study was to assess the effect of medical therapy of RVH on renal autoregulation efficiency in patients with atherosclerotic RAS.

MATERIAL AND METHODS

19 persons (38 kidneys) in 2 groups: 1) study: with RVH and stenosis of 1 renal artery - 8 patients; 2) control: - 11 healthy volunteers. Doppler captopril test with RI measurements and estimation of creatinine clearance (CCr) were performed in both groups at baseline, and after a period of controlled medical therapy (CMT) only in the study group. ABPM was evaluated in controls at baseline, and in the study group at the end of CMT.

RESULTS

In the study group the mean period of CMT was 8.3 ±2.7 months, the number of antihypertensive drugs was 4.1 ±1.0, and mean 24-hour blood pressure was 138/74 mmHg. Mean CCr was stable during the study. Significant increase of RI after captopril was found only in controls. At baseline, in the group of kidneys with a non-stenotic renal artery, significant lowering of RI was observed, and ΔRI differed significantly from controls. After CMT, ΔRI increased in non-stenotic kidneys in comparison to the baseline, and did not differ from controls.

CONCLUSIONS

Adequate medical therapy of RVH preserved renal function and improved renal autoregulation efficiency in non-stenotic kidneys.

Renal vascular response to angiotensin II inhibition in intensive antihypertensive treatment of essential hypertension

INTRODUCTION

High blood pressure (BP) leads to target organ damage. It is suggested that regression of early organ lesions is possible on condition of BP normalization. The study objective was to assess whether permanent reduction of BP to the recommended values modifies renal vascular response to acute angiotensin II inhibition in the Doppler captopril test (DCT) in patients with essential hypertension (EH).

MATERIAL AND METHODS

Twenty-nine persons (58 kidneys) were found eligible for the study: 18 patients with EH and 11 healthy volunteers constituting the control group. Glomerular filtration rate estimation (eGFR), 24-h ambulatory BP monitoring (ABPM) and DCT with evaluation of renal resistive index change (ΔRI) were performed before and after a 6-month period of intensive antihypertensive therapy (IAT). Additional ABPM was performed at the end of IAT.

RESULTS

The mean IAT period was 8.5 ±2.4 months. The mean 24-h values of systolic and diastolic BP in the EH group were significantly lower in the IAT period than at the beginning and at the end of the study. Significantly lower systolic and diastolic BP (p < 0.05) and improvement of renal function (eGFR 121 ±38 vs. 139 ±40 ml/min, p < 0.001) were found after IAT as compared to initial values. Before IAT, ΔRI was significantly lower in the EH group as compared to the controls, but no such differences were found after IAT.

CONCLUSIONS

In EH patients, intensive BP lowering to the recommended values was associated with improvement of renal function and normalisation of renal vascular response to acute angiotensin II inhibition.

Is nonalbuminuric renal insufficiency in type 2 diabetes related to an increase in intrarenal vascular disease?

OBJECTIVE

To investigate the role of intrarenal vascular disease in the pathogenesis of nonalbuminuric renal insufficiency in type 2 diabetes.

RESEARCH DESIGN AND METHODS

We studied 325 unselected clinic patients who had sufficient clinical and biochemical information to calculate an estimated glomerular filtration rate (eGFR) using the Modified Diet in Renal Disease six-variable formula, at least two estimations of urinary albumin excretion rates (AER), and a renal duplex scan to estimate the resistance index of the interlobar renal arteries. The resistance index, measured as part of a complications surveillance program, was compared in patients with an eGFR < or >or=60 ml/min per 1.73 m(2) who were further stratified into normo- (AER <20), micro- (20-200), or macroalbuminuria (> 200 microg/min) categories.

RESULTS

Patients with an eGFR <60 ml/min per 1.73 m(2) had a higher resistance index of the renal interlobar arteries compared with patients with an eGFR >or=60 ml/min per 1.73 m(2). However, the resistance index was elevated to a similar extent in patients with an eGFR <60 ml/min per 1.73 m(2) regardless of albuminuric status (normo- 0.74 +/- 0.01, micro- 0.73 +/- 0.01, and macroalbuminuria resistance index 0.75 +/- 0.11). Multiple regression analysis revealed that increased age (P < 0.0001), elevated BMI (P = 0.0001), decreased eGFR (P < 0.01), and decreased diastolic blood pressure (P < 0.01), but not an increased AER, were independently associated with an elevated resistance index in patients with impaired renal function.

CONCLUSIONS

Subjects with type 2 diabetes and reduced glomerular filtration rate had similar degrees of intrarenal vascular disease, as measured by the intrarenal arterial resistance index, regardless of their AER status. The pathological mechanisms that determine the relationship between impaired renal function and AER status in subjects with type 2 diabetes remain to be elucidated.

Effect of low-density lipoprotein apheresis on urinary protein and podocyte excretion in patients with nephrotic syndrome due to diabetic nephropathy

BACKGROUND

The aim of the present study is to determine whether low-density lipoprotein (LDL) apheresis affects proteinuria and urinary podocyte excretion in patients with type 2 diabetes and nephrotic syndrome.

METHODS

LDL apheresis was performed on patients with diabetes with long-standing nephrotic syndrome, and urinary protein level and number of urinary podocytes were compared between these patients (5 men, 3 women; mean age, 54.6 years) and 10 nephrotic patients with diabetes not treated with LDL apheresis (6 men, 4 women; mean age, 56.5 years).

RESULTS

LDL apheresis reduced total cholesterol (P < 0.001), LDL cholesterol ( P < 0.001), lipoprotein(a) (P < 0.001), creatinine (P < 0.05), and blood urea nitrogen (P < 0.05) levels and increased creatinine clearance (P < 0.05). The LDL apheresis group showed a significant decrease in urinary protein excretion (from 10.8 +/- 3.2 to 1.8 +/- 1.1 g/d; P < 0.001) and number of urinary podocytes (from 4.8 +/- 2.2 to 0.9 +/- 0.4 cells/mL; P < 0.01).

CONCLUSION

These data suggest that LDL apheresis effectively reduces proteinuria and podocyte excretion, ameliorating renal dysfunction in patients with nephrotic syndrome caused by diabetic nephropathy.

Interactions between Renin Angiotensin System and Advanced Glycation in the Kidney

Although hemodynamic and metabolic factors are individually implicated in the development of diabetic nephropathy, their interaction has not been defined clearly. In this study, the effects of angiotensin II (Ang II) and advanced glycation end products (AGE) both individually on each other are explored and compared. In the first study arm, Sprague-Dawley rats received a continuous infusion of AGE-modified rat serum albumin (RSA) or unmodified RSA for 4 wk with or without the angiotensin receptor type 1 antagonist valsartan. In the second arm, animals received a continuous infusion of Ang II (58.3 ng/kg per min) with or without the AGE inhibitor pyridoxamine. Components of the intrarenal renin-angiotensin system were measured using real time reverse transcription-PCR, immunohistochemistry, and standard angiotensin-converting enzyme (ACE) activity assays. Renal and serum AGE were quantified by immunohistochemistry, ELISA, and AGE-fluorescence. After an infusion of AGE-RSA, renal expression of angiotensinogen, ACE, renin, and angiotensin receptor type 1 were increased significantly (all P < 0.01), and ACE activity was elevated. This was associated with tubular and glomerular hypertrophy and AGE accumulation, which could be antagonized by valsartan. However, valsartan had no effect on increased filtration fraction associated with an AGE-RSA infusion. At the same time, an infusion of Ang II increased the serum and renal accumulation of AGE and advanced oxidation protein products and induced renal hypertrophy and salt retention that could be antagonized by pyridoxamine. However, pyridoxamine had no effect on renal vasoconstriction manifested by reduced renal blood flow. AGE and Ang II have overlapping activities in the kidney. The beneficial effects of blockade of either pathway underline the importance of this interaction in diabetic renal disease and the aging kidney.