Determinants of urinary albumin excretion reduction in essential hypertension: A long-term follow-up study

High miR-126-3p levels associated with cardiovascular events in a general population

BACKGROUND

Endothelial dysfunction is a forerunner of atherosclerosis, leading to cardiovascular disease, and albuminuria is a marker of endothelial dysfunction. Circulating levels of microRNAs are emerging as potential biomarkers for cardiovascular disease. Here we estimate the predictive value of a plasma microRNAs signature associated with albuminuria in the incidence of cardiovascular events.

METHODS

Plasma microRNAs quantified in hypertensive patients by next generation sequencing were validated in a cohort of patients and controls by real-time quantitative PCR. The microRNAs found to be associated with albuminuria were analysed for their prognostic value in predicting cardiovascular events incidence on a retrospective, population-based study (Hortega Study), using Cox proportional hazard models.

RESULTS

A plasma microRNA profile was identified in the discovery cohort (n = 48) associated with albuminuria and three microRNAs (miR-126-3p, miR-1260b and miR-374a-5p) were confirmed in the validation cohort (n = 98). The microRNA signature discriminates urinary albumin excretion at baseline (n = 1025), and predicts the incidence of cardiovascular events and coronary heart disease and stroke in a general population retrospective study within a 14-year follow-up (n = 926). High miR-126-3p levels were associated with a shorter time free of both cardiovascular events (HR=1.48, (1.36-1.62), p < 0.0001), as well as coronary artery disease and stroke combined (HR=2.49, (2.19-2.83), p < 0.0001).

CONCLUSIONS

An increased plasma microRNAs profile was identified in hypertensive patients with albuminuria. Increased miR-126-3p suggest it may serve as a prognostic marker for cardiovascular events in a long-term general population. Further studies will assess the potential role of miR-126-3p as a guide for the status of endothelial dysfunction.

Arterial Destiffening in Previously Untreated Mild Hypertensives After 1 Year of Routine Clinical Management

BACKGROUND

Arterial stiffness, measured with pulse wave velocity (PWV), is now classified as a marker of target organ damage (TOD) alongside left ventricular hypertrophy and moderately increased albuminuria. Interventional studies on treated hypertensive patients have shown that PWV could be improved. Our aim was to assess changes in arterial stiffness after 1 year of routine clinical practice in never-treated hypertensive patients.

PATIENTS AND METHODS

We studied 356 never-treated patients with suspected hypertension. After standard clinical assessment during which presence of TOD was evaluated, hypertension diagnosis was confirmed in 231 subjects who subsequently received standard routine care. Both hypertensive and the 125 controls came back for a follow-up visit after 1 year.

RESULTS

Hypertensive patients were slightly older (46 ± 12 vs. 50 ± 12 years, P < 0.001), with higher mean arterial pressure (MAP)-adjusted PWV compared to controls (8.6 ± 2.0 vs. 8.0 ± 1.7 m/s, P < 0.001) and 47% of them presented 1 or more TOD. After 1 year of treatment, MAP was similar in both groups (94.9 vs. 96.2 mm Hg; P = ns), but adjusted PWV remained significantly higher in the hypertensive patients (7.8 ± 1.4 vs. 8.3 ± 1.7 m/s, P = 0.004). The prevalence of elevated PWV was reduced from 20% to 12%. All antihypertensive drugs achieved the same blood pressure (BP) and PWV reduction with the exception of vasodilating beta-blockers which gave slightly better results probably due to heart rate reduction.

CONCLUSION

BP reduction in newly diagnosed hypertensive patients improves arterial stiffness within a year of real-life clinical practice. Patients with the highest PWV and the largest reduction of BP "destiffened" the most whatever antihypertensive class was used.

Subclinical Kidney Damage in Hypertensive Patients: A Renal Window Opened on the Cardiovascular System. Focus on Microalbuminuria

The kidney is one of the major target organs of hypertension.Kidney damage represents a frequent event in the course of hypertension and arterial hypertension is one of the leading causes of end-stage renal disease (ESRD).ESRD has long been recognized as a strong predictor of cardiovascular (CV) morbidity and mortality. However, over the past 20 years a large and consistent body of evidence has been produced suggesting that CV risk progressively increases as the estimated glomerular filtration rate (eGFR) declines and is already significantly elevated even in the earliest stages of renal damage. Data was supported by the very large collaborative meta-analysis of the Chronic Kidney Disease Prognosis Consortium, which provided undisputable evidence that there is an inverse association between eGFR and CV risk. It is important to remember that in evaluating CV disease using renal parameters, GFR should be assessed simultaneously with albuminuria.Indeed, data from the same meta-analysis indicate that also increased urinary albumin levels or proteinuria carry an increased risk of all-cause and CV mortality. Thus, lower eGFR and higher urinary albumin values are not only predictors of progressive kidney failure, but also of all-cause and CV mortality, independent of each other and of traditional CV risk factors.Although subjects with ESRD are at the highest risk of CV diseases, there will likely be more events in subjects with mil-to-moderate renal dysfunction, because of its much higher prevalence.These findings are even more noteworthy when one considers that a mild reduction in renal function is very common in hypertensive patients.The current European Society of Hypertension (ESH)/European Society of Cardiology (ESC) guidelines for the management of arterial hypertension recommend to sought in every patient signs of subclinical (or asymptomatic) renal damage. This was defined by the detection of eGFR between 30 mL/min/1.73 m² and 60 mL/min/1.73 m² or the presence of microalbuminuria (MAU), that is an amount of albumin in the urine of 30-300 mg/day or an albumin/creatinine ratio, preferentially on morning spot urine, of 30-300 mg/g.There is clear evidence that urinary albumin excretion levels, even below the cut-off values used to define MAU, are associated with an increased risk of CV events. The relationships of MAU with a variety of risk factors, such as blood pressure, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced CV risk conferred by MAU. Nonetheless, several studies showed that the association between MAU and CV disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between MAU and CV risk remain to be elucidated. The simple search for MAU and in general of subclinical renal involvement in hypertensive patients may enable the clinician to better assess absolute CV risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard CV risk factors.

Prognostic Value of Microalbuminuria During Antihypertensive Treatment in Essential Hypertension

Whether changes over time of urinary albumin excretion have prognostic value is a matter of discussion. The objective was to assess the prognostic value of changes in urinary albumin excretion over time in cardiovascular risk during antihypertensive treatment. Follow-up study of 2835 hypertensives in the absence of previous cardiovascular disease (mean age 55 years, 47% men, BP 138/80 mm Hg, 19.1% diabetics, and calibrated systemic coronary risk estimation 5 or >10.6%). Usual-care of antihypertensive treatment was implemented to maintain blood pressure <140/90 mm Hg. Urinary albumin excretion was assessed yearly, and the values were expressed as the creatinine ratio. Incidence of cardiovascular events, fatal and nonfatal, was recorded during the follow-up. During a median follow-up of 4.7 years (17 028 patients-year), 294 fatal and first nonfatal cardiovascular events were recorded (1.73 CVD per 100 patients/year). Independently of blood pressure, estimated glomerular filtration rate, level of cardiovascular risk, and antihypertensive treatment, microalbuminuria at baseline and at any time during the follow-up resulted in higher risk for events, hazard ratio (HR) 1.35 (95% confidence interval [CI], 1.08–1.79) and HR 1.49 (95% CI, 1.14–1.94), respectively. Likewise, development of microalbuminuria (HR 1.60; 95% CI, 1.04–2.46) or persistence from the beginning (1.53; 95% CI, 1.13–2.06) had a significantly higher rate of events than if remained normoalbuminuric (HR 1) or regress to normoalbuminuria (HR 1.37; 95% CI, 0.92–2.06) with an 18%, 18%, 8%, and 11% events, respectively, P <0.001. The study supports the value of urinary albumin excretion assessment as a prognostic factor for cardiovascular risk, but also opens the way to consider it as an intermediate objective in hypertension.

Treatment of metabolic acidosis in patients with stage 3 chronic kidney disease with fruits and vegetables or oral bicarbonate reduces urine angiotensinogen and preserves glomerular filtration rate

Alkali therapy of metabolic acidosis in patients with chronic kidney disease (CKD) with plasma total CO2 (TCO2) below 22 mmol/l per KDOQI guidelines appears to preserve estimated glomerular filtration rate (eGFR). Since angiotensin II mediates GFR decline in partial nephrectomy models of CKD and even mild metabolic acidosis increases kidney angiotensin II in animals, alkali treatment of CKD-related metabolic acidosis in patients with plasma TCO2 over 22 mmol/l might preserve GFR through reduced kidney angiotensin II. To test this, we randomized 108 patients with stage 3 CKD and plasma TCO2 22-24 mmol/l to Usual Care or interventions designed to reduce dietary acid by 50% using sodium bicarbonate or base-producing fruits and vegetables. All were treated to achieve a systolic blood pressure below 130 mm Hg with regimens including angiotensin converting enzyme inhibition and followed for 3 years. Plasma TCO2 decreased in Usual Care but increased with bicarbonate or fruits and vegetables. By contrast, urine excretion of angiotensinogen, an index of kidney angiotensin II, increased in Usual Care but decreased with bicarbonate or fruits and vegetables. Creatinine-calculated and cystatin C-calculated eGFR decreased in all groups, but loss was less at 3 years with bicarbonate or fruits and vegetables than Usual Care. Thus, dietary alkali treatment of metabolic acidosis in CKD that is less severe than that for which KDOQI recommends therapy reduces kidney angiotensin II activity and preserves eGFR.

Regression of left ventricular hypertrophy and microalbuminuria changes during antihypertensive treatment

OBJECTIVE

The objective of the present study was to assess the regression of left ventricular hypertrophy (LVH) during antihypertensive treatment, and its relationship with the changes in microalbuminuria.

INDIVIDUALS AND METHODS

One hundred and sixty-eight previously untreated patients with echocardiographic LVH, 46 (27%) with microalbuminuria, were followed during a median period of 13 months (range 6-23 months) and treated with lifestyle changes and antihypertensive drugs. Twenty-four-hour ambulatory blood pressure monitoring, echocardiography and urinary albumin excretion were assessed at the beginning and at the end of the study period.

RESULTS

Left ventricular mass index (LVMI) was reduced from 137 [interquartile interval (IQI), 129-154] to 121 (IQI, 104-137) g/m (P < 0.001). Eighty-nine patients (53%) had a reduction in LVMI of at least 17.8 g/m, and an LVH regression rate of 43.8 per 100 patient-years [95% confidence interval (CI) 35.2-53.9]. The main factor related to LVH regression was the reduction in SBP24 h [multivariate odds ratio (ORm) 4.49; 95% CI 1.73-11.63; P = 0.005, highest tertile compared with lower tertiles]. Male sex (ORm 0.39; 95% CI 0.17-0.90; P = 0.04) and baseline glomerular filtration rate less than 90 ml/min per 1.73 m (ORm 0.39; 95% CI 0.17-0.90; P = 0.03) were associated with a lower probability of LVH regression. Patients with microalbuminuria regression (urinary albumin excretion reduction >50%) had the same odds of achieving regression of LVH as patients with normoalbuminuria (ORm 1.1; 95% CI 0.38-3.25; P = 0.85). However, those with microalbuminuria at baseline, who did not regress, had less probability of achieving LVH regression than the normoalbuminuric patients (OR 0.26; 95% CI 0.07-0.90; P = 0.03) even when adjusted for age, sex, initial LVMI, GFR, blood pressure and angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) treatment during the follow-up.

CONCLUSION

Patients who do not have a significant reduction in microalbuminuria have less chance of achieving LVH regression, independent of blood pressure reduction.

High-normal diastolic blood pressure is a risk for development of microalbuminuria in the general population: the Watari study

OBJECTIVE

Although hypertension is a well known risk factor for microalbuminuria, it is unclear whether blood pressure less than 140/90 mmHg could be a risk for microalbuminuria. We assessed the relationship between baseline blood pressure and the future onset of microalbuminuria in the general population.

METHODS

We studied 2603 town inhabitants of Watari, located in the southeastern part of Miyagi prefecture, Japan. Demographic data, medical history, sitting blood pressure, fasting blood chemistry, and urinary albumin-creatinine ratio were measured at baseline and were followed annually during the next 3 years.

RESULTS

Among 2338 individuals who were normoalbuminuric at baseline (albumin-creatinine ratio <30 mg/g Cr), 161 developed microalbuminuria (albumin-creatinine ratio 30-299 mg/g Cr) during a mean follow-up period of 2.4 years. Incident microalbuminuria patients were older (63.7 ± 8.6 vs. 61.4 ± 10.5 years; P < 0.01), included fewer men (31.1 vs. 40.1%; P < 0.05), had a greater BMI (23.8 ± 3.6 vs. 23.1 ± 3.1 kg/m²; P < 0.01), higher blood pressures (133.5 ± 18.1/75.8 ± 11.9 vs. 127.6 ± 18.1/73.4 ± 11.0 mmHg; P < 0.01 for both systolic and diastolic), higher triglycerides (median 1.18 vs. 1.02 mmol/l; P < 0.01), higher fasting blood glucose (median 5.05 vs. 4.94 mmol/l; P < 0.01), higher urinary albumin excretion (median 13.0 vs. 5.9 mg/g Cr; P < 0.001), and lower serum creatinine concentrations (59.2 ± 12.8 vs. 61.4 ± 13.2 μmol/l; P < 0.05) compared to persistent normoalbuminuric individuals. Multivariate Cox proportional hazards analysis including all covariates revealed that only baseline urinary albumin excretion was an independent predictor for future microalbuminuria, whereas high-normal DBP, triglyceride, and fasting blood glucose concentrations were all significant predictors in the model excluding urinary albumin excretion.

CONCLUSIONS

High-normal DBP associated with metabolic disorders could initiate glomerular damage, leading to future microalbuminuria.

A comparison of treating metabolic acidosis in CKD stage 4 hypertensive kidney disease with fruits and vegetables or sodium bicarbonate

BACKGROUND AND OBJECTIVES

Current guidelines recommend Na(+)-based alkali for CKD with metabolic acidosis and plasma total CO2 (PTCO2) < 22 mM. Because diets in industrialized societies are typically acid-producing, we compared base-producing fruits and vegetables with oral NaHCO3 (HCO3) regarding the primary outcome of follow-up estimated GFR (eGFR) and secondary outcomes of improved metabolic acidosis and reduced urine indices of kidney injury.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Individuals with stage 4 (eGFR, 15-29 ml/min per 1.73 m(2)) CKD due to hypertensive nephropathy, had a PTCO2 level < 22 mM, and were receiving angiotensin-converting enzyme inhibition were randomly assigned to 1 year of daily oral NaHCO3 at 1.0 mEq/kg per day (n=35) or fruits and vegetables dosed to reduce dietary acid by half (n=36).

RESULTS

Plasma cystatin C-calculated eGFR did not differ at baseline and 1 year between groups. One-year PTCO2 was higher than baseline in the HCO3 group (21.2±1.3 versus 19.5±1.5 mM; P<0.01) and the fruits and vegetables group (19.9±1.7 versus 19.3±1.9 mM; P<0.01), consistent with improved metabolic acidosis, and was higher in the HCO3 than the fruits and vegetable group (P<0.001). One-year urine indices of kidney injury were lower than baseline in both groups. Plasma [K(+)] did not increase in either group.

CONCLUSIONS

One year of fruits and vegetables or NaHCO3 in individuals with stage 4 CKD yielded eGFR that was not different, was associated with higher-than-baseline PTCO2, and was associated with lower-than-baseline urine indices of kidney injury. The data indicate that fruits and vegetables improve metabolic acidosis and reduce kidney injury in stage 4 CKD without producing hyperkalemia.

Dietary acid reduction with fruits and vegetables or bicarbonate attenuates kidney injury in patients with a moderately reduced glomerular filtration rate due to hypertensive nephropathy

The neutralization of dietary acid with sodium bicarbonate decreases kidney injury and slows the decline of the glomerular filtration rate (GFR) in animals and patients with chronic kidney disease. The sodium intake, however, could be problematic in patients with reduced GFR. As alkali-induced dietary protein decreased kidney injury in animals, we compared the efficacy of alkali-inducing fruits and vegetables with oral sodium bicarbonate to diminish kidney injury in patients with hypertensive nephropathy at stage 1 or 2 estimated GFR. All patients were evaluated 30 days after no intervention; daily oral sodium bicarbonate; or fruits and vegetables in amounts calculated to reduce dietary acid by half. All patients had 6 months of antihypertensive control by angiotensin-converting enzyme inhibition before and during these studies, and otherwise ate ad lib. Indices of kidney injury were not changed in the stage 1 group. By contrast, each treatment of stage 2 patients decreased urinary albumin, N-acetyl β-D-glucosaminidase, and transforming growth factor β from the controls to a similar extent. Thus, a reduction in dietary acid decreased kidney injury in patients with moderately reduced eGFR due to hypertensive nephropathy and that with fruits and vegetables was comparable to sodium bicarbonate. Fruits and vegetables appear to be an effective kidney protective adjunct to blood pressure reduction and angiotensin-converting enzyme inhibition in hypertensive and possibly other nephropathies.

Is longitudinal pulse pressure a better predictor of 24-hour urinary albumin excretion than other indices of blood pressure?

The strong relationship between urinary albumin excretion (UAE) and pulse pressure (PP) in cross-sectional studies suggests that pressure pulsatility may contribute to renal microvascular injury. The longitudinal relationships between UAE and the various indices of blood pressure (BP) are not well studied. We compared the associations of UAE with the longitudinal exposure to PP and systolic, diastolic, and mean BPs. UAE was measured from 24-hour urine collections in 450 community-dwelling subjects (age: 57+/-15 years, 53% women, all with UAE <200 microg/min). For each subject, longitudinal indices of BP were estimated by dividing the area under the curve of serial measurements of BP (median: 5) during 1 to 22 years preceding UAE measurement by the number of follow-up years. Median (interquartile range) UAE was 4.7 microg/min (3.3 to 7.8 microg/min) in women and 5.2 microg/min (3.7 to 9.8 microg/min) in men. In women, UAE was not related to longitudinal indices of BP. In men, in multivariable-adjusted models that included either longitudinal systolic and diastolic BPs or longitudinal PP and mean BP, UAE was independently associated with systolic (standardized regression coefficient [beta]=0.227; P=0.03) but not with diastolic (beta=-0.049; P=0.59) BP and with PP (beta=0.216; P=0.01) but not with mean BP (beta=0.032; P=0.72). Comparisons of these 2 models and stepwise regression analyses both indicated that, of the 4 longitudinal indices of BP, PP was the strongest predictor of UAE in men. The pulsatile component of BP confers the highest risk for BP-induced renal microvascular injury. Future studies should examine whether PP reduction provides additional renoprotection beyond that attained by conventional BP goals alone.

Higher brachial-ankle pulse wave velocity as an independent risk factor for future microalbuminuria in patients with essential hypertension: the J-TOPP study

OBJECTIVE

Brachial-ankle pulse wave velocity (baPWV) is a new measure of arterial stiffness. We have shown that a higher baPWV is associated with more severe albuminuria in patients with essential hypertension. However, it is still unclear as to whether baPWV predicts the future albuminuria status in patients under standard care.

METHODS

A total of 321 nondiabetic patients with essential hypertension who had normoalbuminuria or microalbuminuria and were receiving treatment under the current hypertension guidelines were followed up for 2 years. Resting BP, fasting blood glucose, urinary albumin excretion and baPWV were measured before treatment, and periodically thereafter for 2 years.

RESULTS

A 2-year treatment regimen lowered BP from 156/93 to 135/81 mmHg (P < 0.0001) and reduced the incidence of microalbuminuria from 25.8 to 14.0%. To determine the predictors for future microalbuminuria status, we compared the baseline data between patients with normoalbuminuria (n = 276) and those with microalbuminuria (n = 45) 2 years after the treatment. The microalbuminuric patients had a significantly higher baPWV and urinary albumin excretion and a significantly lower high-density lipoprotein concentration than the normoalbuminuric patients. Furthermore, the frequency of the use of renin-angiotensin system inhibitors was significantly lower in the microalbuminuric patients than in the normoalbuminuric patients. A multiple logistic regression analysis showed that higher baPWV was an independent risk factor for microalbuminuria 2 years after treatment of hypertension. When we restricted our analysis to a cohort of patients without microalbuminuria at the baseline, we found that higher baPWV was an independent predictor of the development of microalbuminuria after 2 years.

CONCLUSION

Higher baPWV could be an independent risk factor for future microalbuminuria in patients with essential hypertension.

Spironolactone and doxazosin treatment in patients with resistant hypertension

INTRODUCTION AND OBJECTIVES

The aim of this study was to evaluate the use of spironolactone and doxazosin as treatment for patients with resistant hypertension.

METHODS

This retrospective study involved 181 outpatients with resistant hypertension (defined as a failure of blood pressure [BP] control despite treatment with three drugs, one of which was a diuretic) who received additional spironolactone (n=88) or doxazosin (n=93).

RESULTS

Mean systolic BP in the spironolactone group fell by 28 mmHg (95% confidence interval [CI], 24-32 mmHg; P< .001) and mean diastolic BP fell by 12 mmHg (95% CI, 9-14 mmHg; P< .001). The corresponding falls in the doxazosin group were 16 mmHg (95% CI, 13-20 mmHg; P< .001) and 7 mmHg (95% CI, 5-9 mmHg; P< .001), respectively. The decrease was significantly greater with spironolactone for both systolic (P< .001) and diastolic (P=.003) pressures. At the end of follow-up, 30% of all patients had achieved BP control, with control being more frequent with spironolactone (39%) than doxazosin (23%; P=.02). Multivariate logistic regression analysis showed that the only factors that significantly influenced the achievement of BP control were diabetes (odds ratio=0.17; 95% CI, 0.08-0.39; P< .001) and baseline systolic BP <165 mmHg (odds ratio=2.56; 95% CI, 1.11-5.90; P=.03).

CONCLUSIONS

In patients with resistant hypertension, the addition of either spironolactone or doxazosin resulted in a significant decrease in BP, though the decrease appeared to be greater with spironolactone. The presence of diabetes complicated BP control.