The renal consequences of arterial hypertension

Multi-Spectroscopic, thermodynamic and molecular docking studies to investigate the interaction of eplerenone with human serum albumin

The binding of small molecular drugs with human serum albumin (HSA) has a crucial influence on their pharmacokinetics. The binding interaction between the antihypertensive Eplerenone (EPL)and HSA was investigated using multi-spectroscopic techniques for the first time. These techniques include UV-Vis spectroscopy, Fourier Transform Infrared (FT-IR), native fluorescence spectroscopy, synchronous fluorescence spectroscopy and molecular docking approach. The fluorescence spectroscopic study showed that EPL quenched HSA inherent fluorescence. The mechanism for quenching of HSA by EPL has been determined to be static in nature and confirmed by UV absorption and fluorescence spectroscopy. The modified Stern-Volmer equation was used to estimate the binding constant (K_b ) as well as the number of bindings (n). The results indicated that the binding occurs at a single site (Kb;2.238 x 10³ L mol^-1 at 298 K). The enthalpy and entropy changes (∆H and ∆S) were 58.061 and 0.258 K J mol^-1 , respectively, illustrating that the principal intermolecular interactions stabilizing the EPL-HSA system are hydrophobic forces. Synchronous fluorescence spectroscopy revealed that EPL binding to HSA occurred around the tyrosine residue (Tyr) and this agreed with the molecular docking study. The FRET analysis confirmed the static quenching mechanism. The esterase enzyme activity of HSA was also evaluated showing its decrease in the presence of EPL. Furthermore, docking analysis and site-specific markers experiment revealed that EPL binds with HSA at subdomain IB (site III).

Adherence to a Healthy Sleep Pattern and Risk of Chronic Kidney Disease: The UK Biobank Study

OBJECTIVE

To examine the association of a healthy sleep pattern, characterized by sleep of 7 to 8 h/d, morning person, no insomnia, no frequent snoring, and no daytime sleepiness, with the risk of chronic kidney disease (CKD).

METHODS

We included 392,218 European adults, aged 38 to 73 years, who were free of CKD at recruitment between March 13, 2006, and October 1, 2010, from the UK Biobank study. Data on sleep behaviors were collected through questionnaires at recruitment. Cox proportional hazards regression models were used to assess the relations between the healthy sleep score and risk of CKD.

RESULTS

We identified 18,842 incident CKD cases after a mean follow-up of 11.1 (SD 2.2) years. The healthy sleep score was inversely associated with the risk of CKD in a dose-dependent manner (P for trend, <.001). Compared with the participants with a poor sleep pattern (score of 0-1), the multivariate adjusted hazard ratio of CKD was 0.77 (95% CI, 0.71 to 0.84) for those with the healthiest sleep pattern (score of 5). In addition, we found that the inverse association was stronger in individuals without history of hypertension compared with individuals with hypertension at baseline (P for interaction, .003) and in those 60 years of age or younger compared with their older counterparts (P for interaction, <.001).

CONCLUSION

Our data suggest that adherence to an overall healthy sleep pattern is associated with a lower risk of CKD, especially for individuals without history of hypertension and those who are younger.

Negative correlation of urinary miR-199a-3p level with ameliorating effects of sarpogrelate and cilostazol in hypertensive diabetic nephropathy

The prevalence of chronic kidney disease is increasing globally; however, effective therapeutic options are limited. In this study, we aimed to identify urinary miRNAs reflecting the effect of therapeutic intervention in rats with comorbid hypertension and diabetes. Additionally, the potential beneficial effects of anti-platelet sarpogrelate and cilostazol were investigated. Nephropathy progression in streptozotocin (STZ)-treated spontaneously hypertensive rats (SHRs), including albuminuria, collagen deposition, and histopathological changes, was alleviated by sarpogrelate and antihypertensive agent telmisartan. Global analysis of urinary miRNAs identified that miR-199a-3p was commonly reduced by sarpogrelate and telmisartan treatment. In vitro analysis suggested CD151 as a target gene of miR-199a-3p: miR-199a-3p overexpression repressed CD151 levels and miR-199a-3p interacted with the 3'-untranslated region of the CD151 gene. In addition, we demonstrated that the miR-199a-3p/CD151 axis is associated with the transforming growth factor-β1 (TGF-β1)-induced fibrogenic pathway. TGF-β1 treatment led to miR-199a-3p elevation and CD151 suppression, and miR-199a-3p overexpression or CD151-silencing enhanced TGF-β1-inducible collagen IV and α-smooth muscle actin (α-SMA) levels. In vivo analysis showed that the decrease in CD151 and the increase in collagen IV and α-SMA in the kidney from STZ-treated SHR were restored by sarpogrelate and telmisartan administration. In an additional animal experiment using cilostazol and telmisartan, there was a correlation between urinary miR-199a-3p reduction and the ameliorating effects of cilostazol or combination with telmisartan. Collectively, these results indicate that urinary miR-199a-3p might be utilized as a marker for nephropathy treatment. We also provide evidence of the benefits of antiplatelet sarpogrelate and cilostazol in nephropathy progression.

Chronic kidney disease and HIV in the era of antiretroviral treatment: findings from a 10-year cohort study in a west African setting

Background

It has been reported that people living with HIV in West Africa exhibited the highest risks for chronic kidney disease (CKD) in the world. Here, we aimed at determining the CKD frequency and changes in kidney function during antiretroviral treatment (ART) in a large cohort of HIV-patients followed in Burkina Faso.

Methods

We included ART-naive adults who initiated ART at the Day Care Unit of the Souro Sanou University Hospital between 01/01/2007 and 12/31/2016. We assessed the estimated glomerular filtration rate (eGFR) by serum creatinine using the Modification of Diet in Renal Disease (MDRD) equation. Following the K/DOQI recommendations, CKD was defined as eGFR < 60 ml/min/1.73m² at two consecutive measurements at least 3 months apart. The factors associated with eGFR decline or CKD were identified by mixed linear regression and Cox regression, respectively.

Results

Three thousand, one hundred and thirty-eight patients (72% women) were followed for a median (IQR) of 4.5(2.2–6.9) years. At baseline, median eGFR (IQR) was 110.7(94.4–128.4) ml/min/1.73m² and 93 (3%) patients exhibited eGFR < 60 ml/min/1.73m². The lowest-performing progressions of eGFR during the first year of ART were observed in patients with 40-49 yr. age range (− 8.3[− 11.7;-5.0] ml/min/1.73m², p < 0.001), age ≥ 50 yr. (− 6.2[− 10.7;-1.8] ml/min/1.73m², p = 0.006) and high blood pressure (HBP) (− 28.4[− 46.9;-9.9] ml/min/1.73m², p = 0.003) at ART initiation. Regarding the ART exposure in patients with normal baseline eGFR, zidovudine (AZT) with protease inhibitor (PI) (− 4.7[− 7.7;-1.6] ml/min/1.73m², p = 0.002), tenofovir (TDF) + PI (− 13.1[− 17.4;-8.7] ml/min/1.73m², p < 0.001), TDF without PI (− 3.2[− 5.0;-1.4] ml/min/1.73m², p < 0.001), stavudine (d4T) + PI (− 8.5[− 14.6–2.4] ml/min/1.73m², p = 0.006) and d4T without PI (− 5.0[− 7.6–2.4] ml/min/1.73m², p < 0.001) were associated with poorer eGFR progression. The prevalence of CKD was 0.5% and the incidence was 1.9 [1.3; 2.7] cases/1000 person-years. The risk of CKD was higher in patients with HBP (4.3[1.8;9.9], p = 0.001), 40-49 yr. patients (4.2[1.6;11.2], p = 0.004), ≥50 yr. patients (4.5[1.5;14.1], p = 0.009) and patients exposed to abacavir (ABC) or didanosine (ddI) based ART (13.1[4.0;42.9], p < 0.001).

Conclusions

Our findings do not confirm the high risk of CKD reported in previous studies of West Africans with HIV, but support the recommendations for early initiation of ART and close kidney function monitoring in patients with HBP or aged ≥40 yr.

Long-Term Consequences of Complex Living Renal Donation: Is It Safe?

INTRODUCTION

As there is a paucity of literature regarding the long-term outcomes of complex living donors, we conducted this study to assess the effect of kidney donation on the complex living kidney donor.

MATERIALS AND METHODS

This retrospective study was conducted in Narayan Health Hospital, Kolkata, Eastern India. The cohort consisted of complex living kidney donors who donated kidneys between the years 2007 and 2012. All donors were 60 years old or older, or were younger than 60 years and had comorbidities like hypertension and obesity. After a minimum follow-up of 5 years, all donors underwent evaluation. Data pertaining to hypertension, new-onset diabetes, body mass index (BMI), estimated glomerular filtration rate (eGFR) and albuminuria, and cardiac events were compared from the time of donation till 5 years post-transplant.

RESULTS AND DISCUSSION

We found a statistically significant increase in blood pressure, number of antihypertensives used, and mean BMI at follow-up. Diabetes mellitus was developed in 22.3% of donors. The mean GFR also decreased significantly at follow-up. There were 42 elderly donors (≥60 years) and 23 ≤ 59 years of age. There was a significant fall of eGFR in both groups, but the percentage fall was similar in both groups. A significant percentage of donors developed proteinuria, the majority being hypertensives.

CONCLUSION

Procurement of kidneys from marginal donors should be done cautiously, and donors should be assessed for morbidity and mortality in the future, as we found a statistically significant deterioration in renal function, blood pressure, and BMI over long-term follow-up.

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.

Progression of microalbuminuria in SHR is associated with lower expression of critical components of the apical endocytic machinery in the renal proximal tubule

Cumulative epidemiological evidence indicates that the presence of microalbuminuria predicts a higher frequency of cardiovascular events, peripheral disease, and mortality in essential hypertension. Microalbuminuria may arise from increased glomerular permeability and/or reduced proximal tubular reabsorption of albumin by receptor-mediated endocytosis. This study aimed to evaluate the temporal pattern of urinary protein excretion and to test the hypothesis that progression of microalbuminuria is associated with decreased protein expression of critical components of the endocytic apparatus in the renal proximal tubule of spontaneously hypertensive rats (SHR). We found that urinary albumin excretion increased progressively with blood pressure in SHR from 6 to 21 wk of age. In addition, SDS-PAGE analysis of urinary proteins showed that microalbuminuric SHR virtually excreted proteins of the size of albumin or smaller (<70 kDa), typical of tubular proteinuria. Moreover, the protein abundance of the endocytic receptors megalin and cubilin as well as of the chloride channel ClC-5 progressively decreased in the renal cortex of SHR from 6 to 21 wk of age. Expression of the vacuolar H⁺-ATPase B2 subunit was also reduced in the renal cortex of 21-wk-old compared with both 6- and 14-wk-old SHR. Collectively, our study suggests that enhanced urinary protein excretion, especially of albumin, may be due, at least in part, to lower expression of key components of the apical endocytic apparatus in the renal proximal tubule. Finally, one may speculate that dysfunction of the apical endocytic pathway in the renal proximal tubule may contribute to the development of microalbuminuria in essential hypertension.

Renal Vascular Lesions in Patients with Diabetes Mellitus

Background and Aims. Patients with diabetes mellitus, especially type 2 diabetes, have often a multifactorial renal impairment. The aim of this study was to correlate renal vascular lesions occurring in patients with diabetes mellitus with clinical and laboratory parameters. Material and method. We performed a retrospective study on a sample of 127 patients with diabetes mellitus, who died in hospital. Data from necropsies were correlated with the clinical and laboratory data collected from the medical records of these patients. Results. Renal vascular lesions were frequently found in patients from the study group. The most common were nephroangiosclerosis lesions, which correlated with age, diabetes duration, systolic blood pressure and mean fasting glucose. Conclusions. Most patients in the study group had multiple cardiovascular risk factors (advanced age, dyslipidemia, hypertension) that explain the high prevalence of renal vascular lesions.

The progressive pathway of microalbuminuria: from early marker of renal damage to strong cardiovascular risk predictor

There is clear evidence that urinary albumin excretion levels, even below the cut-off values currently used to diagnose microalbuminuria, are associated with an increased risk of cardiovascular events. The relationships of microalbuminuria with a variety of risk factors, such as hypertension, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced cardiovascular risk conferred by microalbuminuria. Nonetheless, several studies showed that the association between microalbuminuria and cardiovascular disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between microalbuminuria and cardiovascular risk remain incompletely understood. The simple search for microalbuminuria in hypertensive patients may enable the clinician to better assess absolute cardiovascular 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 cardiovascular risk factors.

Clinical value of urinary kidney biomarkers for estimation of renal impairment in elderly Chinese with essential hypertension

The purpose of this work was to observe the excretion of specific types of urinary proteins and urinary enzymes in elderly essential hypertension patients, for early detection and targeted treatment of hypertensive nephropathy in the elderly. A total of 120 elderly essential hypertensive patients and 38 healthy elderly volunteers were involved. The urinary excretion rate of retinal-binding protein (RBP), transferrin (Tf), albumin (Alb), and urinary enzyme N-acetyl-beta-D-glucosaminidase (NAG) activity were determined. Patients were divided into two groups according to their creatinine clearance (Cockroft-Gault formula). There were 88 patients in group A, whose glomerular filtration rate (GFR) was >or=80 mL/min, and 32 patients in group B with a GFR <80 mL/min. Among the essential hypertensive patients, urinary excretion rates of RBP, Alb, Tf, and NAG were increased in both groups compared with the healthy controls. But the amount of urinary protein differed between group A and group B. The excretion rate of specific urinary protein and urinary enzyme had a positive relationship with the duration of course of hypertension. We believe that specific types of urinary proteins and urinary enzymes may be useful markers for early diagnosis of hypertensive nephropathy; they can also be regarded as a clinical indicator of the progression of hypertensive nephropathy, serving in the assessment of therapeutic effects.

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

OBJECTIVE

The objective of the present study was to assess factors related to long-term changes in urinary albumin excretion (UAE) of nondiabetic microalbuminuric (n = 252) or proteinuric hypertensive individuals (n = 58) in a prospective follow-up.

METHOD

After enrollment, patients were placed on usual care including nonpharmacological treatment and/or treatment with an antihypertensive drug regime to achieve blood pressure < 135/85 mmHg. Periodic UAE measurements were performed until regression or significant reduction (defined when UAE dropped > 50% from the initial values, plus reduction of UAE to < 30 mg/24 h for microalbuminuric patients and < 300 mg/24 h for proteinuric patients).

RESULTS

Among the microalbuminuric patients, 113 (44.8%) significantly reduced UAE after a mean follow-up of 18 months (range 12-69 months), 20.3/100 patients per year. Among the proteinuric patients, 29 (50%) significantly reduced UAE after a mean follow-up of 25 months (range 12-51 months), 20.2/100 patients per year. The baseline glomerular filtration rate, diastolic blood pressure and fasting glucose during follow-up were independent factors related to the regression or significant reduction in a Cox proportional hazard model. Regression of UAE was independently related to initial estimated glomerular filtration rate < or = 60 ml/min per 1.73 m (hazard ratio, 0.57; 95% confidence interval, 0.38-0.86; P = 0.001) and DBP > or = 90 mmHg achieved during the follow-up (hazard ratio, 0.57; 95% confidence interval, 0.38-0.86; P = 0.001), even when adjusted for age, gender, body mass index, fasting glucose, presence of treatment at the beginning of the study and treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers during the follow-up.

CONCLUSIONS

The reduction of urinary albumin excretion was linked to the preserved glomerular filtration rate and to adequate blood pressure control.

Blood Pressure and Renal Function after Kidney Donation from Hypertensive Living Donors

BACKGROUND

Rising numbers of patients reaching end-stage kidney disease intensify the demand for expansion of the living-kidney-donor pool. On the basis of low risk in white donors with essential hypertension, our transplant center undertook a structured program of accepting hypertensive donors if kidney function and urine protein were normal. This study reports outcomes of hypertensive donors 1 year after kidney donation.

METHODS

We studied detailed measurements of blood pressure (oscillometric, hypertensive therapy nurse [RN], and ambulatory blood pressure monitoring [ABPM]), clinical, and renal characteristics (iothalamate glomerular filtration rate [GFR], urine protein, and microalbumin) in 148 living kidney donors before and 6 to 12 months after nephrectomy. Twenty-four were hypertensive (awake ABPM>135/85 mm Hg and clinic/RN BP>140/90 mm Hg) before donation.

RESULTS

After 282 days, normotensive donors had no change in awake ABPM pressure (pre 121 +/- 1/75 +/- 2 vs. post 120 +/- 1/ 5 +/- 1 mm Hg), whereas BP in hypertensive donors fell with both nonpharmacologic and drug therapy (pre 142 +/- 3/85 +/- 2 to post 132 +/- 2/80 +/- 1 mm Hg, P<.01). Hypertensive donors were older (53.4 vs. 41.4 years, P<.001) and had lower GFR after kidney donation (61 +/- 2 vs. 68 +/- 1 mL/min/1.73m, P<.01). After correction for age, no independent BP effect was evident for predicting GFR either before or after nephrectomy. Urine protein and microalbumin did not change in either group after donor nephrectomy.

CONCLUSIONS

Our results indicate that white subjects with moderate, essential hypertension and normal kidney function have no adverse effects regarding blood pressure, GFR, or urinary protein excretion during the first year after living kidney donation. Although further studies are essential to confirm long-term safety, these data suggest that selected hypertensive patients may be accepted for living kidney donation.

Doxazosin GITS trough to peak ratio and 24-hour blood pressure monitoring in the management of hypertension in renal transplant patients

We have studied 20 patients, 10 male, 10 female, mean age 52.5+/-10.9 years, who received a cadaver kidney transplant between June 1996 and January 1999. The patients presented with mild or moderate high BP and were treated on a maintained immunosuppression with an anti-calcineurin agent and steroids, associated or not to mycophenolate-mofetil. At baseline, a 24-hour ambulatory BP monitoring was performed. General biochemical parameters were determined and doxazosin GITS (Gastro-Intestinal Therapeutic System) in a single dose of 4 mg/d was started. Doxazosin GITS was titrated four weeks after up to 8 mg/d if the BP was greater than 140/90 mm Hg. At week 12, biochemical analysis were repeated as well as the 24-hour BP monitoring and the T/P ratio was calculated.

RESULTS

The patients were divided in responders, T/P index >50%, n=10 or not-responders, T/P index <50%, n=10 patients). No differences in systolic BP (SBP), diastolic BP(DBP), plasma creatinine or proteinuria were seen at base-line. DBP was lower in responders than in non-responders (P=ns). Doxazosin doses were 5.5+/-3 mg/d vs 5.8+/-3 and T/P ratio 0.70+/-0.13 vs 0.17+/-0.14, (P=.001). There were no variations in pl. t. cholesterol, triglycerides, glucose or uric acid.

CONCLUSIONS

Treatment was safe and efficient, not increasing metabolic adverse effects. Doxazosin GITS is a safe agent which can reduce cardiovascular risk. In our patients, the good T/P ratio has been associated with a best diastolic BP control. This good profile should be taken into account for 24-hour BP control in hypertensive renal transplant patients.

Blood pressure evaluation among older living kidney donors

With more patients reaching end-stage renal disease, the demand for living kidney donation is increasing rapidly. Many potential donors are now in older age groups. The effects of increasing BP with age and the measurement criteria for hypertension in this group are not well defined. A total of 238 potential donors between 18 and 72 yr of age were prospectively studied, with a comparison of "clinic" BP values measured in the outpatient clinic with an oscillometric recorder (Dinamap; Critikon), ambulatory BP monitoring (ABPM) findings, and standardized BP values determined by nurses using American Heart Association criteria. Renal function was evaluated on the basis of iothalamate clearance (GFR) and urinary protein and microalbumin excretion. Ninety-six percent of subjects were Caucasian. All subjects exhibited normal GFR and urinary protein excretion. Three age groups were defined (group I, </=35 yr, n = 64; group II, 36 to 49 yr, n = 109; group III, >/= 50 yr, n = 65). BP increased with age, as determined with all methods. Subjects >/= 50 yr of age exhibited the highest clinic readings (145 +/- 2/83 +/- 1 mmHg, compared with 129 +/- 2/76 +/- 1 mmHg for group I, P < 0.01). Awake ABPM and nurse-determined BP measurements were lower than clinic readings, including those for group III (131 +/- 2/80 +/- 1 mmHg, compared with 145 +/- 2/83 +/- 1 mmHg in the clinic, P < 0.001). With the use of systolic BP values of >140 mmHg and/or diastolic BP values of >90 mmHg, 36.7% of subjects were initially considered hypertensive; this proportion decreased to 11% overall with awake ABPM findings (>135/85 mmHg). Measurement variability (SD in ABPM) and the effects of misclassification were greatest for donors >/= 50 yr of age. Multivariate regression indicated that GFR of both donors and recipients decreased with age, but regression identified no independent effect of BP. Recipient outcomes for up to 2 yr were equally good for donor kidneys considered normotensive or hypertensive on the basis of clinic BP measurements. These data indicate that higher arterial BP with age can lead to misclassification of many older living kidney donors. Sixty-two subjects with excellent kidney function were misclassified as hypertensive with clinic oscillometric measurements alone. Detailed evaluations of ABPM findings, GFR, and urinary protein levels are warranted for Caucasian subjects with high clinic BP readings who are otherwise suitable potential donors.

Left ventricular hypertrophy is associated with asymptomatic cerebral damage in hypertensive patients

BACKGROUND AND PURPOSE

It has been demonstrated that left ventricular hypertrophy (LVH) confers an increased risk for major cerebrovascular events. However, it is still uncertain whether there is an association between LVH and asymptomatic cerebrovascular damage in hypertensive patients. In this study, we investigated the relation between LVH, evaluated by both echocardiography (Echo-LVH) and electrocardiography (ECG-LVH), and preclinical cerebral damage, as identified by magnetic resonance imaging.

METHODS

One hundred ninety-five consecutive patients were enrolled in the study. We evaluated other risk factors such as age, sex, presence of diabetes, cholesterol levels, smoking status, heart rate, and systolic and diastolic blood pressure. Asymptomatic cerebrovascular damage was considered silent cerebral lesions: punctate lesions, lacunes, and territorial lesions. Patients were divided into 2 groups according to the presence of asymptomatic brain lesions.

RESULTS

The 2 groups of patients differed only in terms of age and systolic pressure. More importantly, the prevalence of Echo-LVH (83% versus 47.7%, P<0.001) and ECG-LVH (56% versus 22%, P<0.001) was significantly higher in patients with asymptomatic brain lesions. A multivariate analysis allowed us to recognize LVH as the only independent predictor for the presence of ischemic lacunes (P<0.001). Moreover, we evaluated the impact of left ventricular geometry on asymptomatic cerebrovascular damage, and we found that hypertensives with concentric hypertrophy displayed more pronounced asymptomatic cerebrovascular damage compared with patients with eccentric hypertrophy.

CONCLUSIONS

Our study demonstrates that LVH is associated with cerebral damage even in the absence of clinical symptoms. Thus, the presence of cardiac damage provides important prognostic clues about the presence of asymptomatic cerebral damage.

Glomerular hyperfiltration in hypertensive African Americans

The incidence of end-stage renal disease attributable to hypertension is 5-fold greater in African Americans than in whites. To determine whether glomerular hyperfiltration is an antecedent to renal failure, we compared responses of renal blood flow and glomerular filtration rate to graded infusions of norepinephrine (0. 01, 0.025, and 0.05 microg. kg(-1). min(-1) for 30 minutes each) in 29 African Americans and 33 age-matched French Canadian whites with essential hypertension. Renal blood flow and glomerular filtration rate were measured by using a constant-infusion technique of PAH and inulin, respectively. Studies were conducted on an inpatient clinical research center, and antihypertensive medications had been discontinued for at least 1 week. Based on 24-hour blood pressure monitoring, nighttime blood pressures decreased (P<0.01) in the French Canadians but not in the African Americans. Baseline renal blood flow was higher (P<0.05) in the African Americans (1310+/-127 mL. min(-1) per 1.73 m(2)) than in the French Canadians (1024+/-42 mL. min(-1) per 1.73 m(2)); baseline glomerular filtration rate was also higher (P<0.01) in the African Americans (140+/-4 versus 121+/-4 mL. min(-1) per 1.73 m(2)). In response to norepinephrine-induced blood pressure increases, renal blood flow was autoregulated and did not change in either patient group. In the African Americans, glomerular filtration rate increased (P<0.01) to 167 mL. min(-1) per 1.73 m(2) during the first norepinephrine infusion, without subsequent change. In contrast, glomerular filtration rate did not change with norepinephrine-induced increases of blood pressure in the French Canadians. In the African Americans, the elevation of baseline glomerular filtration rate, with a further increase in response to norepinephrine, may be indicative of glomerular hyperfiltration. Glomerular hyperfiltration and lack of nocturnal blood pressure decline may contribute to the higher incidence of end-stage renal disease in hypertensive African Americans.

Importance of blood pressure reduction for prevention of progression of renal disease

Despite reduction of stroke and coronary mortality rates, progression of renal disease to end stage continues to occur with increasing frequency. Recent studies emphasize common pathways of elevated arterial pressures that produce increased glomerular capillary pressures and increase filtered proteins in the urinary space. Such proteinuria, along with activation of the intrarenal renin-angiotensin system, endothelin, and inflammatory cytokines, magnifies progressive renal injury and fibrosis. Malignant forms of hypertension with severe arteriolar injury and proteinuria can be treated effectively with current antihypertensive regimens with improved patient survival. Several recent studies indicate improved renal outcomes in proteinuric diseases, generally regardless of the specific antihypertensive agent. Recent trials of hypertensive subjects with minimal proteinuria demonstrate slower rates of disease progression than that seen in subjects with proteinuria above 1 gram per day. Reduction of arterial pressures, particularly when it leads to reduced proteinuria, can slow the progression of many renal diseases.

Treatment of hypertension after renal transplantation: long-term efficacy of verapamil, enalapril, and doxazosin

Normal blood pressure is a good marker of graft survival after renal transplantation, and effective antihypertensive treatment reduces the progression of graft damage. We conducted a long-term follow-up study of 88 hypertensive renal transplant recipients, all of whom were taking sustained cyclosporine A (CsA) immunosuppression. The patients were treated for at least three years, and initially received 240 mg/day of verapamil (N = 24, group I), 5 mg/day of enalapril (N = 24, group II) or 1 mg/day of doxazosin (N = 40, group III). Baseline creatinine did not differ in the three groups, but proteinuria was higher in the enalapril group (7 patients had proteinuria > 1.5 g/day). Treatment was withdrawn in 5 patients in the verapamil group, 5 in the enalapril group and 2 in the doxazosin group due to drug-related side effects. Blood pressure (BP) control at three years was equivalent in the three groups (systolic BP, group I 157 +/- 12; group II 149 +/- 19; group III 154 +/- 21; diastolic BP, group I 90 +/- 8.7, group II 84 +/- 9.8, group III 90.5 +/- 16; mean BP, group I 113 +/- 7, group II 106 +/- 10, group III 106 +/- 29). Two patients in group I, 3 in group II and 15 in group III required additional antihypertensive drugs. CsA levels increased in the verapamil-treated patients, allowing for an early decrease in CsA doses (1 year doses, 3.3 +/- 1 mg/kg body wt/day in group I, 4.3 +/- 1.6 in group II, 3.7 +/- 1.6 in group III). Six cardiovascular events occurred, 3 in group I, 1 in group II, and 2 in group III patients. One patient died in the enalapril group and another in the doxazosin group. Eight verapamil-treated patients, 8 enalapril-treated patients and 4 doxazosin-treated patients lost their grafts due to biopsy-proven chronic transplant nephropathy. In conclusion, the three antihypertensive agents are effective in reducing blood pressure, with no clear advantage of one above any other. Verapamil allows the CsA dose to be reduced, thus decreasing the cost of immunosupression. Enalapril can be a more effective antiproteinuric agent, but hyperkalemia or impaired allograft function may occur in patients with non-optimal allograft function. Doxazosin offers an excellent safety and efficacy profile, and when not efficient by itself in controlling blood pressure, is an ideal concomitant agent in hypertensive renal transplant patients.

Renal vascular disease in the elderly

The aging of Western societies is causing a progressive increase in the number of patients over 65 starting dialysis. The EDTA Registry shows that in 1995 this section of the population represented nearly 45% of patients under dialysis, and the percentage is even higher in the USRDS at 48%, 20% of whom are over 75. These changes have not only been quantitative, but have also modified the causes of end-stage renal disease (ESRD). Diabetic nephropathy (DN) and renal vascular disease (RVD) account for more than 50% of all these causes, reaching 66% according to the latest USRDS calculations. According to these numbers, RVD represents 29% of all causes, the incidence varying with the age group, and has become the main cause of ESRD in the elderly (38% of all cases). Until a few years ago, RVD was synonymous with hypertension, but as the population ages, the range of diseases in this group is increasing. The main RVDs that cause ESRD in the elderly are: hypertensive RVD (nephrosclerosis), atheromatous RVD (either as ischemic atherosclerotic nephropathy or as atheroembolism), and acute occlusion of renal arteries (either bilateral or unilateral in single-kidney patients). The diagnosis of nephrosclerosis in the absence of histological confirmation is a presumed clinical diagnosis, made in most cases by exclusion, and is therefore clearly overestimated. On the other hand, atheromatous RVD is an underdiagnosed disease that is often overlooked. The prevalence, natural history, diagnosis and prognosis are discussed in this report.

Renal protection by antihypertensive drugs: insights from microalbuminuria studies

During the last few years there has been a renewed interest in blood-pressure (BP)-induced kidney damage, owing to a progressive increase in the incidence and prevalence of hypertension and vascular diseases as a cause of end-stage renal disease (ESRD). The need to prevent ESRD demands continued efforts so as to identify early those people with hypertension who are at risk and to provide them with effective antihypertensive therapy. This review analyses what is needed in terms of surrogate endpoints for monitoring kidney damage and what is known about the impact of antihypertensive treatments in reducing the BP burden on the kidney in non-diabetic subjects. Although glomerular filtration rate (GFR) and proteinuria are useful surrogate endpoints for patients with nephropathy and GFR below or close to the threshold value for renal insufficiency, it is clear that monitoring changes in either GFR or proteinuria does not provide a sensitive endpoint for subjects with the mildest forms of renal disease, e.g. essential hypertensive patients who are at risk of developing kidney damage. In this case microalbuminuria may be useful, although unequivocal evidence demonstrating that microalbuminuria is a risk marker for developing renal insufficiency in non-diabetic renal diseases has not existed until now, and whether a decrease in microalbuminuria is of prognostic significance in patients with essential hypertension remains to be demonstrated. The beneficial effects of the antihypertensive agents on microalbuminuria are also proportional to BP reduction. If a large enough BP reduction is achieved there seem to be, at most, only minimal differences among the antihypertensive drug classes. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers have additional beneficial effects on microalbuminuria independent of the BP reduction, owing to their direct role in glomerular haemodynamics. The heterogeneity in the changes in urinary albumin excretion during antihypertensive treatment may be related to the different factors involved in the presence of microalbuminuria or structural end-organ damage, or both.

Nephroprotective effect of antihypertensive drugs in essential hypertension

BACKGROUND

Effective antihypertensive treatment has prevented target-organ involvement in hypertension, markedly reducing morbidity and mortality from strokes, coronary heart disease, cardiac failure, and hypertensive emergencies. However, the incidence of hypertension-related end-stage renal disease continues to increase, suggesting that therapeutic reduction in arterial pressure by itself is not sufficient to prevent the development of hypertensive renal failure.

OBJECTIVE

To examine experimental and clinical data concerning the protective effect of reduction of arterial pressure on the progression of hypertension-related renal disease, and the evidence indicating that some antihypertensive agents may afford more nephroprotection, over and above that attributable to reduction of arterial pressure.

RESULTS

Results of numerous studies clearly indicate that adequate control of arterial pressure, irrespective of the antihypertensive agent used, slowed the progression of renal disease. Results of some studies suggest that lowering arterial pressure below the level that is usually considered adequate has an additional beneficial effect by slowing the progression of renal injury.

CONCLUSION

Results of a number of studies evaluating nephroprotective effects of various drugs and regimens have indicated that certain agents, most notably angiotensin converting enzyme inhibitors and their combination with calcium antagonists, afford more protection than do others at similar levels of reduction of arterial pressure. Results of still other studies suggest that certain agents that exert greater nephroprotection are more efficient at controlling arterial pressure. Therefore, further data are needed before any final conclusion can be drawn. However, it is clear that, in order to establish nephroprotection in patients with essential hypertension, the problem should not be further complicated by additional comorbid diseases such as diabetes mellitus.