Relationships between mild hyperuricaemia and aortic stiffness in untreated hypertensive patients

BACKGROUND AND AIMS

Clinical studies exploring the relationship between serum uric acid (SUA) and arterial stiffness yielded conflicting results. Only in a few of these studies, arterial distensibility was examined by measuring aortic pulse wave velocity (PWV), which is considered the gold standard for evaluating arterial stiffness. In none of the previous investigations was the influence of SUA on aortic distensibility assessed, taking into account the effect of albuminuria. The purpose of our study was to comprehensively analyse the relationships between SUA and aortic PWV in a group of essential hypertensive patients.

METHODS AND RESULTS

We enrolled 222 untreated and uncomplicated hypertensive subjects (mean age: 44 ± 10 years; 60% males), without gout. In all patients, SUA and urinary albumin excretion rate (AER) were determined. Moreover, carotid-femoral (c-f) PWV was measured. C-f PWV was significantly higher in hypertensive patients belonging to the uppermost tertile of SUA distribution, compared to subjects of the lowest tertiles (10.9 ± 2.2 vs. 10 ± 1.8 vs. 9.9 ± 1.7 m s(-1); p = 0.001). In univariate analysis, SUA correlated with c-f PWV (r = 0.24; p < 0.001). This association disappeared when AER was added in a multiple regression model, including SUA, age, mean arterial pressure, gender, metabolic syndrome components and glomerular filtration rate.

CONCLUSION

The results of our study showed that, in essential hypertensive subjects, there is a positive relationship between mild hyperuricaemia and aortic stiffness. This association weakened after adjustment for covariates and lost statistical significance after further correction for albuminuria.

Relationships between mild hyperuricaemia and aortic stiffness in untreated hypertensive patients

BACKGROUND AND AIMS

Clinical studies exploring the relationship between serum uric acid (SUA) and arterial stiffness yielded conflicting results. Only in a few of these studies, arterial distensibility was examined by measuring aortic pulse wave velocity (PWV), which is considered the gold standard for evaluating arterial stiffness. In none of the previous investigations was the influence of SUA on aortic distensibility assessed, taking into account the effect of albuminuria. The purpose of our study was to comprehensively analyse the relationships between SUA and aortic PWV in a group of essential hypertensive patients.

METHODS AND RESULTS

We enrolled 222 untreated and uncomplicated hypertensive subjects (mean age: 44 ± 10 years; 60% males), without gout. In all patients, SUA and urinary albumin excretion rate (AER) were determined. Moreover, carotid-femoral (c-f) PWV was measured. C-f PWV was significantly higher in hypertensive patients belonging to the uppermost tertile of SUA distribution, compared to subjects of the lowest tertiles (10.9 ± 2.2 vs. 10 ± 1.8 vs. 9.9 ± 1.7 m s(-1); p = 0.001). In univariate analysis, SUA correlated with c-f PWV (r = 0.24; p < 0.001). This association disappeared when AER was added in a multiple regression model, including SUA, age, mean arterial pressure, gender, metabolic syndrome components and glomerular filtration rate.

CONCLUSION

The results of our study showed that, in essential hypertensive subjects, there is a positive relationship between mild hyperuricaemia and aortic stiffness. This association weakened after adjustment for covariates and lost statistical significance after further correction for albuminuria.

Absence of an independent association between serum uric acid and left ventricular mass in Caucasian hypertensive women and men

BACKGROUND AND AIM

Experimentally uric acid may induce cardiomyocyte growth and interstitial fibrosis of the heart. However, clinical studies exploring the relationship between serum uric acid (SUA) and left ventricular (LV) mass yielded conflicting results. The aim of our study was to evaluate the relationships between SUA and LV mass in a large group of Caucasian essential hypertensive subjects.

METHODS AND RESULTS

We enrolled 534 hypertensive patients free of cardiovascular complications and without severe renal insufficiency. In all subjects routine blood chemistry, including SUA determination, echocardiographic examination and 24 h ambulatory blood pressure (BP) monitoring were obtained. In the overall population we observed no significant correlation of SUA with LV mass indexed for height(2.7) (LVMH(2.7)) (r = 0.074). When the same relationship was analysed separately in men and women, we found a statistically significant correlation in female gender (r = 0.27; p < 0.001), but not in males (r = -0.042; p = NS). When we grouped the study population in sex-specific tertiles of SUA, an increase in LVMH(2.7) was observed in the highest tertiles in women (44.5 ± 15.6 vs 47.5 ± 16 vs 55.9 ± 22.2 g/m(2.7); p < 0.001), but not in men. The association between SUA and LVMH(2.7) in women lost statistical significance in multiple regression analyses, after adjustment for age, 24 h systolic BP, body mass index, serum creatinine and other potential confounders.

CONCLUSIONS

Our findings do not support an independent association between SUA and LV mass in Caucasian men and women with arterial hypertension.

Glycaemic variability using continuous glucose monitoring and endothelial function in the metabolic syndrome and in Type 2 diabetes

AIMS

Subjects who are at increased risk of developing diabetes may have increased glycaemic variability associated with endothelial dysfunction and possibly subclinical atherosclerosis, which may lead to increased cardiovascular risk observed at the time of diabetes diagnosis. To investigate this hypothesis, we measured endothelial function, carotid intima-media thickness and glycaemic variability using 48-h continuous subcutaneous glucose monitoring in 3 groups of overweight or obese subjects--those without the metabolic syndrome, and those with the metabolic syndrome with or without newly diagnosed Type 2 diabetes.

METHODS

Consecutive subjects, aged 30-65 years with a body mass index >or= 25 kg/m(2) were recruited. Patients were classified as with or without the metabolic syndrome,or as metabolic syndrome with newly diagnosed Type 2 DM. Glycaemic variability was calculated in terms of the coefficient of variation. Endothelial function was measured using brachial artery flow-mediated dilation.

RESULTS

We identified 75 subjects. Mean flow mediated dilation decreased (P < 0.001) and carotid intima-media thickness increased (P < 0.05) across groups. Flow mediated dilation predictors included mean 48-h continuous subcutaneous glucose monitoring values (beta = -0.022; P < 0.005) and the coefficient of variation (beta = -0.10; P = 0.01). Carotid intima-media thickness predictors included age (beta = 0.009; P < 0.001) and flow mediated dilation (beta = -0.014; P = 0.076). Patients re-stratified according to cut-offs for mean 48-h glycaemia and variability demonstrated that subjects with high mean glycaemia but low coefficient of variability had similar flow mediated dilation and carotid intima-media thickness to subjects with low mean glycaemia but high coefficient of variation.

CONCLUSIONS

This study suggests that glycaemic variability influences endothelial function even in non-diabetic subjects. Such variability may explain the increased cardiovascular risk observed in patients prior to developing overt Type 2 diabetes.

Clinical correlates of renal dysfunction in hypertensive patients without cardiovascular complications: the REDHY study

Our study was aimed to assess the clinical correlates of different degrees of renal dysfunction in a wide group of non-diabetic hypertensive patients, free from cardiovascular (CV) complications and known renal diseases, participating to the REDHY (REnal Dysfunction in HYpertension) study. A total of 1856 hypertensive subjects (mean age: 47+/-14 years), attending our hypertension centre, were evaluated. The glomerular filtration rate (GFR) was estimated by the simplified Modification of Diet in Renal Disease Study prediction equation. A 24-h urine sample was collected to determine albumin excretion rate (AER). Albuminuria was defined as an AER greater than 20 microg min(-1). We used the classification proposed by the US National Kidney Foundation's guidelines for chronic kidney disease (CKD) to define the stages of renal function impairment. In multiple logistic regression analysis, the probability of having stage 1 and stage 2 CKD was significantly higher in subjects with greater values of systolic blood pressure (SBP) and with larger waist circumference. SBP was also positively related to stage 3 CKD. Stage 3 and stages 4-5 CKD were inversely associated with waist circumference and directly associated with serum uric acid. Age was inversely related to stage 1 CKD and directly related to stage 3 CKD. The factors associated with milder forms of kidney dysfunction are, in part, different from those associated with more advanced stages of renal function impairment.

[Inflammation, oxidative stress and kidney function in arterial hypertension]

Traditional risk factors such as hypertension, diabetes, dyslipidemia, obesity and metabolic syndrome, as well as additional nontraditional risk factors, can damage the kidney directly and by promoting intrarenal atherogenesis. Evidence indicates that increased oxidative stress and inflammation may mediate most of the effects of risk factors on the kidney. An early sign of impending nephropathy is microalbuminuria, defined as urinary excretion of albumin at a rate of 20-200 mg/min. Patients with microalbuminuria, especially in diabetes, may progress along the renal continuum to chronic kidney disease (CKD) (indicated by macroalbuminuria or proteinuria), increased serum creatinine concentration and decreased glomerular filtration rate. Microalbuminuria is now recognized as an important marker not only for renal disease, but above all for cardiovascular risk. Clinical studies have demonstrated a relationship between oxidative stress and inflammatory biomarkers, and a few studies indicate an inverse correlation of oxidative stress biomarkers, assessed by 8-isoprostaglandin F2 alpha, with estimated glomerular filtration rate (eGFR). Moreover, plasma concentrations of high-sensitivity C-reactive protein have been shown to be increased and related to left ventricular mass in CKD individuals having left ventricular hypertrophy. Further, surrogate indexes of atherosclerosis such as intima-media thickness and aortic pulse wave velocity have been demonstrated to be related to plasma concentrations of markers of endothelial activation, inflammation and fibrosis in patients with different stages of CKD. In conclusion, current evidence supports a central role for inflammation in all phases of the atherosclerotic process. On the other hand, in arterial hypertension experimental and clinical data suggest a possible interplay of inflammatory molecules with both oxidative stress and endothelial activation markers. The identification of novel biomarkers and cardiovascular risk factors is needed for prognostic evaluation, cardiovascular and renal prevention, and slowing renal function decline.

A low reported energy intake is associated with metabolic syndrome

BACKGROUND AND AIMS

Metabolic syndrome (MS) may be associated with the presence of an energy-sparing metabolism that predisposes to the excess accumulation of body fat. This study examined the relationship between reported energy intake and obesity in individuals with and without MS.

METHODS AND RESULTS

Ninety consecutive non-diabetic obese subjects were divided into 2 groups based on the presence (MS+: no.=50) or absence (MS-: no.=40) of MS. The study design was cross-sectional. The 3-day food record method was used to assess the subjects' usual energy intake and the Diet Readiness Test (DRT) was also administered. Compared to the MS- group, the MS+ group had a significantly higher body weight, body mass index (mean+/-SEM: 39.1+/-1.3 vs 31.5+/-0.9, p<0.001) and fat mass. The absolute energy intake of the MS+ group (8629+/-331 kJ/24h) did not differ from that of the MS- group (8571+/-515 kJ/24h; p=ns). The daily energy intake normalized for the fat-free mass (FFM) size was higher in the MS- group (163+/-8 kJ/kg-FFM x 24h) than in the MS+ group (138+/-4 kJ/kg-FFM x 24h; p<0.03). The DRT test results were similar in both groups except that section 6 (exercise patterns and attitudes) score was lower in the MS+ group (10.0+/-0.5) than in the MS- group (11.9+/-0.5; p<0.01).

CONCLUSION

The results of this study support the hypothesis that subjects with MS have an energy-sparing metabolism.

Effects of hypocaloric very-low-carbohydrate diet vs. Mediterranean diet on endothelial function in obese women*

Obesity is a cardiovascular risk factor associated with endothelial dysfunction, but the effect of different weight loss strategies on endothelial function is not known. The effect of diet on endothelial function in two hypocaloric diets, a very-low-carbohydrate diet (A) and a Mediterranean diet (M), was measured by brachial artery flow-mediated dilation (FMD). Design Using a longitudinal, randomized, open study design, subjects were engaged in a 2-month weight loss diet. FMD, inflammatory cytokines [interleukin-6 (IL-6) and tumour necrosis factor-alpha] and a marker of oxidative stress [8-iso-prostaglandin F2alpha (8-iso-PGF2alpha)] were measured in subjects on three occasions: before initiating the diet (T0), after 5-7 days of dieting (T5) and after 2 months of dieting (T60). The very short- and medium-term time points were established to discriminate respectively the effect of the diet itself (T5) from that of weight loss (T60). Twenty overweight/obese but otherwise healthy women (BMI: 27-34.9 kg m(-2); age 30-50 years) completed the study. Results Group A lost more weight (mean +/- SEM; -7.6 +/- 0.8 kg) than group M (-4.9 +/- 0.6 kg, P = 0.014) at T60. The FMD was not significantly different between the two groups at T0 (group A: 12.2 +/- 2.9% vs. group B: 10.3 +/- 2.3%, P = ns). In group A, FMD was significantly reduced at T5 and returned to baseline at T60; in group M, FMD increased at T5 and returned to baseline at T60 (P = 0.007 for diet x time interaction). Serum concentrations of IL-6 and 8-iso-PGF2alpha were not significantly different between the two groups at T0 and increased significantly at T5 only in group A (P < 0.001 and P < 0.005 respectively). Conclusion As endothelial dysfunction is known to be associated with acute cardiovascular events, this study suggests that the cardiovascular risk might be increased in the first days of a very-low-carbohydrate diet.

Relationships between metabolic syndrome and left ventricular mass in hypertensive patients: does sex matter?

Several studies documented an association between metabolic syndrome (MetS) and left ventricular (LV) hypertrophy. However, only in a few of these studies the impact of MetS on left ventricular mass (LVM) was separately analysed by gender, with conflicting results. The aim of our study was to verify, in a wide sample of essential hypertensive patients, the influence of gender, if any, on the relationship between MetS and LVM. We enrolled 475 non-diabetic subjects (mean age: 46 +/- 11 years), with mild-to-moderate essential hypertension, of whom 40% had MetS, defined on the basis of Adult Treatment Panel III (ATPIII) criteria. All the patients underwent a 24-h ambulatory blood pressure monitoring and an echocardiogram. LVM indexed for height (2.7) (LVMH (2.7)) was significantly (P < 0.001) higher in women with MetS (n=83) than in those without it (n=97; 54+/-17 vs 42+/-11 g m(-2.7)). An equally significant difference in LVMH (2.7) was documented also in male gender between the two groups with (n=105) and without MetS (n=190; 51+/-14 vs 43+/-11 g m(-2.7); P < 0.001). The relationship between MetS and LVMH (2.7) remained statistically significant (P < 0.001) in both sexes, in multiple regression analyses, even after adjustment for potential confounding factors. Our results seem to suggest that the relationship between MetS and LVM is not significantly affected by gender, being LVM increased in both hypertensive women and men with MetS.

Inverse relationship between ambulatory arterial stiffness index and glomerular filtration rate in arterial hypertension

BACKGROUND

Arterial stiffness and mild-to-moderate renal dysfunction are predictors of cardiovascular (CV) morbidity and mortality. Recently, the ambulatory arterial stiffness index (AASI) has been proposed as a surrogate index of arterial stiffness. It has been associated with an enhanced risk of stroke. The aim of our study was to assess the relationship between AASI and glomerular filtration rate (GFR) in a group of hypertensive patients with no CV complications.

METHODS

A total of 143 untreated hypertensive subjects (mean age: 44 +/- 12 years; men 57%), with serum creatinine <1.5 mg/dl, were enrolled. AASI was calculated as one minus the regression slope of diastolic on systolic blood pressure (BP) obtained by individual 24-h BP recordings. GFR was computed from the scintigraphic determination of the technetium-99m diethylenetriaminepentaacetic acid uptake within the kidneys, by the Gates' method.

RESULTS

Hypertensive patients with AASI above the median value (n = 71) had lower GFR than those with AASI below the median (n = 72) (98.3 +/- 31 vs. 122.4 +/- 32 ml/min/1.73 m(2); P < 0.001). This difference held even after adjustment for age and gender. The linear regression analysis disclosed a significant inverse correlation between GFR and AASI (r = -0.30; P < 0.001), that was replicated (beta = -0.19; P = 0.02) in a multiple regression model including, as independent variables (besides AASI), age, gender, high-density lipoprotein cholesterol, body mass index, 24-h pulse pressure (PP) and nocturnal reduction in BP.

CONCLUSIONS

AASI is inversely related to GFR in arterial hypertension. This may help to explain the increased CV risk associated with mild-to-moderate renal dysfunction.

Association between biomarkers of inflammation and left ventricular hypertrophy in moderate chronic kidney disease

AIMS

Left ventricular hypertrophy (LVH) is a predictor for cardiovascular mortality, and it is considered to be a surrogate marker of preclinical cardiovascular disease. This study aimed at evaluating whether fetuin-A plasma levels are decreased in patients with moderate chronic kidney disease (CKD) and their linkage to plasma concentrations of hs-C-reactive protein (CRP), cardiotrophyn-1 (CT-1), tumor necrosis factor-ac (TNF-alpha), propeptide of collagen Type I (PIP) and to LVH.

MATERIAL AND METHODS

We enrolled 64 moderate CKD and 55 essential hypertensives (EH) with normal renal function as controls. All the patients underwent an echocardiographic examination; plasma samples were obtained to measure routine clinical parameters and the molecules listed above (measured by ELISA).

RESULTS

Among CKD there were 30/64 patients with LVH, and in EH group 14/55 subjects had LVH. Fetuin A was reduced in CKD when compared with EH (p < 0.0001). The comparison between CKD having LVH with those without LVH showed significant differences in plasma levels of fetuin-A (p < 0.002), TNF-alpha (p < 0.01) and hs-CRP (p < 0.001), CT-1 and PIP (p < 0.002). CKD with LVH had lower values of fetuin-A (p < 0.001), and higher values of hs-CRP (p < 0.001) TNF-alpha (p < 0.001), CT-1 (p < 0.001) and PIP (p < 0.001) than EH with LVH. The multivariate analysis of correlation demonstrated that in CKD patients hs-CRP (beta 0.42, p < 0.00006), and systolic blood pressure (beta 0.29, p < 0.02) were independent predictors of LV mass index. The relationship between LV mass index and fetuin-A did not reach statistical significance.

CONCLUSIONS

For the first time in moderate CKD patients, we demonstrate that fetuin-A is decreased and relates to LVH depending on C-reactive protein.

Metabolic syndrome in subjects with white-coat hypertension: impact on left ventricular structure and function

Some reports have suggested that white-coat hypertension (WCH) is associated with some features of the metabolic syndrome (MetS). These metabolic disturbances, instead of WCH per se, may potentially explain the greater extent of end-organ damage sometimes observed in WCH subjects (WCHs) when compared to normotensive individuals (NTs). The aim of the present cross-sectional study was to compare left ventricular (LV) structure and function in three groups of subjects: WCHs with MetS, WCHs without MetS and NTs. A total of 145 WCHs, 35% of whom had MetS, were enrolled. As controls, 35 NTs were also studied. In all subjects, routine blood chemistry, echocardiographic examination and 24-h ambulatory blood pressure monitoring were performed. When compared with WCHs without MetS, those with MetS showed higher LV mass indexed by height elevated by a power of 2.7 (LVMH(2.7)) (49.6+/-14.8 vs 38.9+/-9.8 g/m(2.7); P<0.0001). The same parameter was greater in WCHs without MetS than in NTs (32+/-8 g/m(2.7); P=0.004). Moreover, the E-wave deceleration time was longer in WCHs with MetS than in those without it (236.2+/-66.4 vs 200.5+/-30.8 ms; P<0.0001). The relationship of MetS with LVMH(2.7) was confirmed in multivariate regression models. Our results seem to suggest that MetS may have a deleterious influence on LV structure and function in WCH. However, WCH, being associated with an increased LV mass, also in subjects without MetS, may not be considered as an innocuous phenomenon.

Favorable clinical heart and bone effects of anti-thyroid drug therapy in endogenous subclinical hyperthyroidism

Although subclinical hyperthyroidism (SCH) has been associated with increased risk of osteoporosis and cardiac arrhythmias, its treatment is still controversial. This study was designed as a prospective, randomized, intervention, control-study with a 1-year follow-up in order to investigate whether normalization of serum TSH in SCH using methimazole has favorable bone and heart clinical effects. Fourteen patients with endogenous SCH (not Graves' disease) were enrolled, 7 (5 women/2 men; group T) were treated with methimazole (2.5-7.5 mg/day), and 7 (5 women/2 men; group C) were followed without treatment; 10 healthy subjects were also included in the study as controls. Serum free-T3 (FT3), free-T4 (FT4) and TSH, thyroid echography, bone stiffness index (SI), as measured by heel ultrasonometry, and 24-h electrocardiography monitoring were obtained. SCH patients exhibited higher systolic and diastolic blood pressure than control subjects. They also had a significantly higher number of both ventricular premature beats (VPB) (mean+/-SEM: 681+/-238 vs 6+/-2 beats/24 h; p<0.02) and atrial premature beats (APB) (mean+/-SEM: 495+/-331 vs 7+/-2 beats/24 h; p<0.0001), and a lower SI (66+/-5 vs 96+/-3; p<0.001). Twelve months after normalization of TSH with the use of methimazole, the number of VPB decreased significantly (947+/-443 vs 214+/-109 beats/24 h; p<0.05) while it remained unchanged in untreated SCH patients (414+/-163 vs 487+/-152 beats/24 h; p=ns). An insignificant therapy effect was observed as far as APB were concerned (826+/-660 vs 144+/-75 beats/24 h; p=ns), however their number increased significantly in the untreated group (463+/-49 vs 215+/-46 beats/24 h; p<0.05). The SI increased significantly as a result of therapy in group T (64.1+/-4.8 vs 70.0+/-5.3; p<0.02) and was further reduced in group C at the end of the study (69.1+/-7.3 vs 62.9+/-7.1; p<0.001). No adverse effect was observed in group T. In conclusion, anti-thyroid therapy seems to have favor-able bone and heart clinical effects in subjects with endogenous SCH.

Microalbuminuria and early endothelial activation in essential hypertension

We hypothesized that in essential hypertensive patients (EHs), plasma levels of pro-atherogenic adhesion molecules would be increased and related with urine albumin excretion (UAE). Thus, this study was aimed at evaluating biochemical markers of endothelial activation and their relationship with UAE in a group of patients with uncomplicated EH. In basal condition soluble forms of adhesion molecules intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1, as well as 24-h UAE were assayed. One hundred patients with essential hypertension and no diabetes or ultrasonographic evidence of atherosclerosis were included in the study. Seventy normotensive healthy subjects served as controls. EHs were first studied overall, than were divided into two subgroups: those with UAE > or =20 mcg/min MAUs and those with UAE <20 mcg/min (non-MAUs). ICAM-1 (P<0.001) and VCAM-1 (P<0.0001) plasma concentrations were higher in EHs than in controls. Microalbuminuric EHs had greater levels of adhesion molecules than non-MAUs (ICAM-1 P=0.04; VCAM-1 P=0.02, respectively). In EHs UAE was correlated with ICAM-1 (r=0.29, P=0.003), and VCAM-1 (r=0.30, P=0.002). These associations were confirmed in multiple regression models (P=0.02 for both ICAM-1 and VCAM-1) including, along with adhesion molecules, age, body mass index and blood pressures. Our findings show that in essential hypertension there is a very early activation of endothelial adhesion molecules favouring atherosclerosis.

Oxidative stress and inflammation in long-term renal transplanted hypertensives

INTRODUCTION

Several studies have shown that chronic renal failure (CRF) is characterized by "accelerated atherosclerosis". More recent studies emphasize that inflammation and oxidative stress play a central role in atherosclerosis, and it is well-established that C-reactive protein (CRP) is a cardiovascular risk marker in the general population, in end-stage renal disease (ESRD) patients and in allograft recipients.

METHODS

We measured the serum concentration of high sensitivity CRP, TNFalpha, 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha, an in vivo oxidative stress marker) in 15 CRF patients and in 15 transplant recipients. Exclusion criteria were age < 30 and > 65 years, smoking, diabetes mellitus and history of cardiovascular diseases. Immunosuppressive therapy was not withdrawn, and antihypertensive treatment was the same for both groups. Systolic (SBP) and diastolic blood pressure (DBP), serum creatinine (sCr) and estimated glomerular filtration rate (GFR) were also evaluated. 15 healthy subjects were enrolled as controls.

RESULTS

The transplanted group showed significantly higher values than controls of CRP (p < 0.05), TNFalpha (p < 0.05), 8-iso-PGF2alpha (p < 0.05). The CRF group as well exhibited, in comparison with controls significantly higher concentrations of CRP (p < 0.05), TNFalpha (p < 0.05), and 8-iso-PGF2alpha (p < 0.05). SBP, DBP and sCr were not different between transplanted and CRF patients. CRP was higher in transplant recipients than in CRF patients (p < 0.05). No difference in TNFalpha levels between the 2 groups was found. 8-iso-PGF2alpha was significantly higher in CRF than in the transplanted group (p < 0.05). In this latter, 8-iso-PGF2alpha showed a positive correlation with TNFalpha (p < 0.001), sCr (p < 0.001), SBP (p < 0.05) and DBP (p < 0.05). In the same group both 8-iso-PGF2alpha and TNFalpha were negatively correlated with GFR (r = -0.873 and -0.912, respectively, p < 0.001 for both).

CONCLUSION

Our data have shown the coexistence of an increased oxidative stress and an inflammatory state in long-term renal graft recipients.

In Renal Transplanted Patients Inflammation and Oxidative Stress Are Interrelated

INTRODUCTION

The inflammatory state plays a well-documented role to cause oxidative stress, especially in end-stage renal disease (ESRD) patients, wherein several cardiovascular risk factors are amplified by the coexistence of a microinflammatory state with increased oxidative stress.

METHODS

We measured serum concentrations of high sensitivity C-reactive protein (CRP), tumor necrosis factor alpha (TNFalpha), 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha-in vivo oxidative stress marker) in 15 chronic renal failure (CRF) and 15 transplant patients versus 15 healthy controls. Exclusion criteria were: age <30 or >65 years as well as a diagnosis of diabetes or cardiovascular diseases. We evaluated systolic (SBP) and diastolic blood pressure (DBP), serum creatinine (sCr), and glomerular filtration rate (GFR).

RESULTS

Both the transplanted and the CRF group showed significantly higher values of CRP, TNFalpha, and 8-iso-PGF2alpha than the controls (P < .05 for all). SBP, DBP, and sCr were not different between transplanted and CRF patients. CRP was higher in transplant recipients than in CRF patients (P < .05). No difference in TNFalpha levels was observed between the two groups. 8-iso-PGF2alpha was significantly higher in the CRF than in the transplanted group (P < .05), although the latter cohort showed a positive correlation between 8-iso-PGF2alpha and TNFalpha (P < .001), sCr (P < .001), SBP (P < .05), and DBP (P < .05). In the same group both 8-iso-PGF2alpha and TNFalpha were negatively correlated with GFR (r -.824 and -.866, respectively; P < .001 for both).

CONCLUSION

We observed the coexistence of increased oxidative stress and an inflammatory state among renal graft recipients.

Metabolic syndrome in subjects with essential hypertension: relationships with subclinical cardiovascular and renal damage

It has long been recognized that arterial hypertension is often a part of a larger constellation of anthropometric and metabolic abnormalities that includes abdominal (or visceral) obesity, a characteristic dyslipidemia (low high-density lipoprotein cholesterol and high triglycerides), glucose intolerance, insulin-resistance and hyperuricemia. These traits occur simultaneously to a greater degree than would be expected by chance alone, supporting the existence of a discrete disorder that, over the years, has been defined by a variety of terms, including plurimetabolic syndrome, the deadly quartet, dysmetabolic syndrome, insulin resistance syndrome, cardiometabolic syndrome and more recently metabolic syndrome (MS). In last years some scientific organizations proposed working definitions for MS. Among these definitions, the one suggested by the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP-ATPIII) is the simplest and the most commonly applied. The MS is extremely common worldwide. This high prevalence is of considerable concern because accumulating evidences suggest that the MS, even without type 2 diabetes, carries an increased risk for cardiovascular and renal events. Recently it has been demonstrated that the adverse prognostic impact of MS may also be extended to hypertensive patients. Some recent studies reported an increased prevalence of left ventricular hypertrophy, diastolic dysfunction, early carotid atherosclerosis, impaired aortic distensibility, hypertensive retinopathy and microalbuminuria in hypertensive patients with MS when compared to those without it. The increased occurrence of these early signs of subclinical target organ damage, most of which are recognized as significant independent predictors of adverse cardiovascular and renal outcomes, may partially explain the association of the MS with a higher cardiovascular and renal risk.

Influence of metabolic syndrome on hypertension-related target organ damage

OBJECTIVES

The aim of our study was to analyse, in a wide group of essential hypertensive patients without diabetes mellitus, the influence of metabolic syndrome (MS) (defined according to the criteria laid down in the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults) on markers of preclinical cardiac, renal and retinal damage.

DESIGN

Cross-sectional study.

SETTING

Outpatient hypertension clinic.

SUBJECTS AND METHODS

A total of 353 young and middle-aged hypertensives, free from cardiovascular and renal diseases (and 37% of whom had MS), underwent echocardiographic examination, microalbuminuria determination and non-mydriatic retinography.

RESULTS

When compared with subjects without MS, hypertensive patients with MS exhibited more elevated left ventricular (LV) mass (either normalized by body surface area or by height elevated by a power of 2.7), higher myocardial relative wall thickness, albumin excretion rate (AER) and a greater prevalence of LV hypertrophy (57.7% vs. 25.1%; P < 0.00001), of microalbuminuria (36.2% vs. 19.3%; P = 0.002) and of hypertensive retinopathy (87.7% vs. 48.4%; P < 0.00001). These results held even after correction for age, 24-h blood pressures, duration of hypertension, previous antihypertensive therapy, and gender distribution. The independent relationships between LV mass and MS, and between AER and MS, were confirmed in multivariate regression models including MS together with its individual components.

CONCLUSIONS

MS may amplify hypertension-related cardiac and renal changes, over and above the potential contribution of each single component of this syndrome. As these markers of target organ damage are well-known predictors of cardiovascular events, our results may partly explain the enhanced cardiovascular risk associated with MS.

Low relative resting metabolic rate and body weight gain in adult Caucasian Italians

OBJECTIVE

To investigate the relationship between resting metabolic rate (RMR) and subsequent changes in body size and degree of fatness in a group of adult Caucasian Italians.

DESIGN

Prospective, longitudinal, observational study.

SUBJECTS

In total, 155 subjects (72 males and 83 females, age range: 18-55 y; BMI: 17.5-63.4 kg/m2) were evaluated. In total, 43 (26 m and 17 f; BMI: 28.9+/-1.1 kg/m2, mean+/-s.e.m.) of them were reassessed 10-12 y later.

MEASUREMENTS

Anthropometric and body composition (bioimpedance analysis) parameters and RMR (indirect calorimetry) were taken at baseline and after 10-12 y.

RESULTS

Subjects (15 m, 8 f) who gained body weight (arbitrarily defined as a change in body weight > or = 5 kg) had baseline BMI (29.9+/-1.8 vs 28.0+/-1.4; P = NS) and body composition in terms of fat mass (FM%) and fat-free mass (FFM kg) comparable to those of the subjects (11 m, 9 f) whose body weight remained stable. Baseline RMR was significantly lower in subjects who gained weight than in those who did not (108+/-2.1 vs 122+/-3.1 kJ/kg-FFM 24 h; P < 0.001), although it did not differ significantly between the two groups (119+/-2 vs 121+/-2 kJ/kg-FFM 24 h; P = NS) 10-12 y later. Baseline RMR was inversely correlated to both change in body weight (r = -0.57; P < 0.001) and FM (r = -0.50; P < 0.001).

CONCLUSION

A low RMR normalized for FFM appears to be associated with body weight gain in the long run in adult Caucasian Italians.

Relationship between albumin excretion rate and aortic stiffness in untreated essential hypertensive patients

OBJECTIVES

To evaluate, in a group of nondiabetic essential hypertensive patients with normal renal function, the relationship between albumin excretion rate (AER) and carotid-femoral pulse wave velocity (PWV), as an index of aortic stiffness.

DESIGN

Cross-sectional study.

SETTING

Outpatient hypertension clinic.

SUBJECTS

Seventy patients with mild-to-moderate essential hypertension, aged 42 +/- 8 years, never pharmacologically treated. All subjects underwent routine laboratory tests, 24-h ambulatory blood pressure (BP) monitoring, measurement of carotid-femoral PWV, by means of a computerized method, and AER.

RESULTS

Microalbuminuric patients (AER > or = 20 microg min(-1); n = 19), when compared with normoalbuminuric subjects, showed more elevated 24-h BP (136/88 +/- 10/10 vs. 128/83 +/- 7/6 mmHg; P < 0.001 and P = 0.013, for systolic and diastolic BP respectively) and higher values of carotid-femoral PWV (10.4 +/- 2 m s(-1) vs. 9.2 +/- 1.3; P = 0.006). This latter difference remained statistically significant, even after correction by ancova for 24-h systolic and diastolic BP, and body mass index (BMI, P = 0.016). Univariate regression analysis disclosed a tight correlation between AER and carotid-femoral PWV (r = 0.42; P = 0.0003). This association was confirmed in a multiple regression model (beta = 0.35; P = 0.009) in which, as independent variables, besides PWV, 24-h BP, age, serum glucose values, smoking status, gender and BMI, were added.

CONCLUSIONS

Our results seem to confirm that microalbuminuria may represent the early renal manifestation of a widespread vascular dysfunction, and therefore it is an integrated marker of cardiovascular risk.

Pulsatile and steady 24-h blood pressure components as determinants of left ventricular mass in young and middle-aged essential hypertensives

In order to explore the relations between left ventricular mass (LVM) and the pulsatile (pulse pressure) and steady (mean pressure) components of the blood pressure (BP) curve, 304 young and middle-aged essential hypertensive patients were studied by means of 24-h ambulatory BP monitoring and echocardiography. In the overall study population, both the BP components showed significant correlations with LVM. These correlations were unevenly distributed in the subgroups of subjects younger and in those older than 50 years. While in this latter subgroup, in multivariate analysis, both 24-h mean BP (24-MBP) (beta = 0.27; P = 0.008) and 24-h pulse pressure (24-h PP) (beta = 0.23; P = 0.02) were associated with LVM, in the subset of younger hypertensives only 24-h MBP (beta = 0.21; P = 0.009) was related to LVM, independent of other covariates. The relations observed between 24-h PP and LVM in the entire study population and in the patients older than 50 years lost statistical significance when the effect of 24-h systolic blood pressure (24-h SBP) was taken into account, in a multiple regression model in which 24-h MBP was replaced by 24-h SBP. Our findings seem to suggest that the association of PP with LVM in middle-aged hypertensives may partially explain the increased cardiovascular risk, documented in subjects with high PP. However, this relation is not independent, but is mediated by SBP.

Relationships between 24 h blood pressure load and target organ damage in patients with mild-to-moderate essential hypertension

OBJECTIVE

To analyse the relationships between 24 h blood pressure load (the percentage of systolic/diastolic blood pressures exceeding 140/90 mmHg while awake and 120/80 mmHg during sleep) and some indices of hypertensive target organ involvement, independently of the mean level of 24 h blood pressure.

METHODS

One hundred and thirty patients with mild-to-moderate hypertension underwent 24 h ambulatory blood pressure monitoring, ocular fundus examination, microalbuminuria assay and two-dimensional guided M-mode echocardiography. The study population was divided into subsets according to the systolic and diastolic 24 h blood pressure load values predicted from the regression equation relating 24 h blood pressure load to 24 h mean blood pressure. The subjects with an observed load above this predicted value were included in the higher blood pressure load groups, the remaining ones being included in the lower groups.

RESULTS

Relative myocardial wall thickness and total peripheral resistance were greater, and mid-wall fractional shortening, end-systolic stress-corrected mid-wall fractional shortening and cardiac index lower, in the subjects with a higher systolic blood pressure load. Moreover, the stroke index:pulse pressure ratio was reduced, and a greater prevalence of hypertensive retinopathy was observed in the higher systolic load group. On the contrary, no statistically significant difference was found for any of the cardiac, renal and funduscopic parameters examined when the two groups with a higher and lower 24 h diastolic blood pressure load were compared.

CONCLUSIONS

Our results seem to suggest that, in mild-to-moderate arterial hypertension, a high 24 h systolic blood pressure load may be associated, independently of the average level of 24 h systolic ambulatory blood pressure, with an adverse cardiovascular risk profile.

Insulin, renin-aldosterone system and blood pressure in obese people

OBJECTIVE

To evaluate the relationship between insulin, the renin-aldosterone system and blood pressure in obese subjects.

DESIGN AND METHODS

A cross sectional study of a group of severely obese normotensive subjects who were surgical candidates (n=39; mean BMI: 47.8+/-1.4) and a group of hypertensive patients (n=57; mean BMI: 28.0+/-0.7) twenty-nine of whom had BMI>27. All subjects were studied after 15 days on a balanced diet. Insulin, plasma renin activity and aldosterone were measured.

RESULTS

Fasting insulin, plasma renin activity and aldosterone were higher in severely obese normotensive subjects than in hypertensive subjects (respectively 32.3+/-3.0 vs 13.1+/-1.0 mU/l, P=0.0001; 1.34+/-0.22 vs 0.88+/-0.12 ng/ml/h, P=0.04; 137.2+/-16.2 vs 87.9+/-12.1 pg/ml, P=0.015). Insulin was related to BMI and to aldosterone both in normotensive and in hypertensive patients.

CONCLUSION

Hyperinsulinemia itself does not determine hypertension; in some people it could play a vasodilator role in opposition to the renin-aldosterone system.

Polymorphonuclear integrins, membrane fluidity, and cytosolic Ca(2+) content after activation in essential hypertension

The purpose of this research was to obtain further information about the role of polymorphonuclear leukocytes in essential hypertension. These cells could be involved in the pathogenesis of organ injury. Thirty subjects (14 men and 16 women) with essential hypertension were enrolled. In these subjects we determined, at baseline and after in vitro activation with 4-phorbol 12-myristate 13-acetate and N:-formyl-methionyl-leucyl-phenylalanine, the polymorphonuclear leukocyte membrane fluidity, obtained by labeling the cells with 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3, 5-hexatriene, cytosolic Ca(2+) concentration, obtained by marking the cells with Fura 2-AM, and integrin pattern (CD11a, CD11b, CD11c, and CD18), by using the indirect immunofluorescence with a flow cytometer. At baseline there was no difference in membrane fluidity between normal subjects and hypertensives, whereas hypertensives showed an increase in cytosolic Ca(2+) content and an increase of the phenotypical expression of CD11a, CD11b, and CD18. In normal subjects and in hypertensives, after activation, no variation was found in membrane fluidity and cytosolic Ca(2+) content. In normal subjects, after activation, we observed a significant increase of the expression of all adhesion molecules, whereas in hypertensives we found an increase of the expression of CD11b, CD11c, and CD18 but also a decrease of CD11a. The behavior of the polymorphonuclear leukocyte integrin profile may have several explanations, and in particular, the trend of CD11a after chemotactic activation may be related to its cleavage or to an altered integrin phosphorylation/dephosphorylation balance hypothetically present in this clinical condition.

Sympathetic activity and blood pressure pattern in autosomal dominant polycystic kidney disease hypertensives

To study the potential role of sympathetic activity in the pathogenesis of arterial hypertension associated with autosomal dominant polycystic kidney disease (ADPKD) and to analyze its relationship with 24-hour blood pressure pattern, plasma catecholamines and 24-hour ambulatory blood pressure monitoring were evaluated in 30 ADPKD hypertensive patients (of which 17 without and 13 with renal failure) and in 50 essential hypertensives. The groups were matched for sex, body mass index, known duration of hypertension, and clinic blood pressure. Plasma catecholamines, determined in resting position, were higher in ADPKD patients without renal failure than in essential hypertensives. Nighttime diastolic blood pressure was higher and the percentage day-night difference in mean blood pressure was lower in hypertensives with ADPKD compared to patients with essential hypertension. Blood pressure was significantly correlated with plasma noradrenaline in ADPKD patients, independently of renal function. No significant differences were observed between ADPKD patients with and without renal failure, with respect to plasma catecholamines, 24-hour daytime and nighttime ambulatory blood pressures and the percentage day-night difference in mean blood pressure.

Endothelium-derived factors in microalbuminuric and nonmicroalbuminuric essential hypertensives

Previous evidence has demonstrated a relationship between growth factors and cardiovascular diseases. This study was aimed at evaluating levels of some endothelium-derived growth factors, and their relationship with microalbuminuria (MAU), in essential hypertension. Ninety-nine mild-moderate essential hypertensives (EH) and 25 healthy controls were studied. All patients underwent 24-h blood pressure monitoring, serum endothelin-1 (ET-1), basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF), and 24-h MAU assays. Later, EH were divided into two subsets consisting of microalbuminurics (MAU >11 microg/min) and nonmicroalbuminurics (MAU <11 microg/min). In microalbuminuric EH, circulating ET-1, bFGF, and PDGF were significantly higher than in nonmicroalbuminurics (P < .0001, P < .0001, P < .005, respectively) or in controls. In the group of 99 EH, significant positive correlations of MAU with both ET-1 and bFGF (r = 0.35, P < .001, and r = 0.34, P < .001, respectively) were found. ET-1 and bFGF correlated significantly (r = 0.31, P < .002). Circulating bFGF also correlated significantly with MAU in the microalbuminuric EH subset (r = 0.49, P < .01). Our results show that in microalbuminuric EH circulating levels of certain growth factors are increased. In human essential hypertension these factors are linked with MAU, an early cardiovascular and renal damage marker.

Essential hypertension: leukocyte rheology and polymorphonuclear cytosolic Ca2+ content at baseline and after activation

In 24 hypertensives we evaluated, at baseline, the leukocyte filtration parameters (using the St. George's Filtrometer), polymorphonuclear (PMN) membrane fluidity (with the fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene [TMA-DPH]) and PMN cytosolic Ca2+ content (with the fluorescent probe Fura 2-AM). In a subgroup of hypertensives (n = 17) the PMN filtration parameters, PMN membrane fluidity and cytosolic Ca2+ content were evaluated after in vitro chemotactic activation (prolonged for 5 and 15 min) with two stimulating agents (4-phorbol 12-myristate 13-acetate [PMA] and N-formyl-methionyl-leucyl-phenylalanine [fMLP]). It was evident, from the baseline data, that there was a significant difference in the mononuclear (MN) initial relative flow rate (IRFR), clogging rate (CR) and clogging particles (CP), and in PMN cytosolic Ca2+ content. There were, however, no differences in the filtration parameters of unfractionated leukocytes and PMNs or in PMN membrane fluidity. After activation, in normals and in hypertensives, a significant variation in PMN filtration parameters was evident. In normals no variation was present in PMN membrane fluidity or cytosolic Ca2+ content after activation. In hypertensives, however, we found an increase solely in PMN cytosolic Ca2+ content after fMLP activation. After PMN activation (at 15 min) one parameter (IRFR) of PMN filtration distinguished normal subjects from hypertensives. No difference between the two groups was found in PMN membrane fluidity or PMN cytosolic Ca2+ content after PMN activation.

Comparison of tumour necrosis factor and endothelin-1 between essential and renal hypertensive patients

The present study was performed to compare circulating levels of tumour necrosis factor-alpha (TNFalpha) and plasma endothelin 1 (ET-1), of hypertensive patients with or without renal failure and with those of normotensive healthy subjects. The study population consisted of 21 healthy normotensive subjects and 22 hypertensive patients, 11 with essential hypertension, and 11 with hypertension and chronic renal failure (CRF). Plasma ET-1 levels, serum TNFalpha and creatinine, creatinine clearance, 24-h urinary albumin excretion (UAE) were assayed, and 24-h blood pressure monitoring was obtained in all subjects. Office blood pressure was similar between hypertensive patients with and without CRF. However, 24-h blood pressure was greater in patients with CRF than in those with essential hypertension and normal renal function. Patients with hypertension manifested greater ET-1 levels than normotensive subjects (P < 0.01). Serum TNFalpha and ET-1 levels were higher in hypertensive patients with CRF than in patients with essential hypertension and normotensive subjects. In the 22 hypertensive patients, TNFalpha levels were negatively correlated with serum creatinine (r=0.60; P < 0.01), and ET-1 levels were positively correlated with UAE (r=0.47, P < 0.05). The present study has shown that hypertensive patients, and particularly those with renal insufficiency, manifest abnormal blood levels of ET-1 and TNFalpha. These factors could contribute to both cardiovascular and renal damage.

Influence of vascular load on plasma endothelin-1, cytokines and catecholamine levels in essential hypertensives

In vitro studies demonstrated a relationship between ET-1 and basic Fibroblast Growth Factor (bFGF), and of bFGF with Platelet Derived Growth Factor (PDGF). The present study was carried out to investigate in vivo the behaviour after vascular stress of circulating ET-1, bFGF and PDGF, and catecholamines, and their relationship. In 12 healthy normotensives (NTs) and 15 essential hypertensives (Ehs) venous blood samples to determine circulating ET-1, bFGF and PDGF, and catecholamine (EPI and NE) levels were drawn before and at the third minute of a handgrip test. Blood pressures (BP) and heart rate were automatically recorded before starting, and at 1, 2, and 3 minutes during the test. The NTs showed, in basal condition, lower values than the EHs of all the examined parameters; later, the handgrip test induced significant increases in circulating levels of ET-1, bFGF and catecholamine. In the EHs at the third minute of the exercise significant increases in plasma ET-1 (p < 0.002), bFGF (p < 0.006), and EPI and NE (p < 0.0005) levels were observed. Systolic and diastolic BP significantly increased after handgrip test in NTs and EHs. Plasma ET-1 correlated with bFGF both before (p < 0.01) and at the acme (p < 0.05) of the isometric exercise. Our results show that in EHs plasma ET-1 and bFGF correlate each other, indicating that in human hypertension a linkage between ET-1 and bFGF exists.

Changes of plasma endothelin and growth factor levels, and of left ventricular mass, after chronic AT1-receptor blockade in human hypertension

The stimulation of autocrine and paracrine factors such as basic fibroblast- (bFGF) and platelet-derived (PDGF) growth factors mediates many of the growth-promoting actions of angiotensin II. The aim of this study was to evaluate the effect of chronic AT1-receptor blockade on plasma endothelin-1 (ET-1) and growth factors levels, and on left ventricular mass, in essential hypertension (EH). The study population consisted of 16 patients with mild-moderate EH, and 25 normotensive controls. In the EH patients under basal conditions, and after 3 and 6 months of chronic therapy with Losartan 50 mg/day, we measured serum levels of ET-1, bFGF and PDGF, and tumor necrosis factor (TNF). At the same time, all patients underwent 24-h ambulatory blood pressure monitoring and an echocardiographic evaluation to measure the thickness of the posterior wall (PWT) of the left ventricle and of the interventricular septum (IVS). The healthy controls underwent the same analyses, under basal conditions, at baseline and after 3 and 6 months of observation. In the EH patients, after 3 months of AT1-receptor blockade bFGF was reduced from 13.6 +/- 0.7 to 10.9 +/- 0.7 pg/mL (P < .004), and both TNF and PDGF were significantly decreased (P < .006 and P < .007, respectively). After 6 months of therapy, ET-1 was significantly diminished in comparison with baseline (6.9 +/- 0.8 v 5.5 +/- 0.1 fmol/mL; P < .05), and the reduction in the levels of growth factors were even more significant than at 3 months of treatment. Both PWT and IVS were significantly changed after 6 months of therapy with losartan after basal evaluation (P < .05, respectively). Systolic and diastolic 24-h blood pressures declined significantly after 3 and 6 months of therapy with losartan (P < .01, respectively). It seems likely that the inhibition of the action of angiotensin II by the specific AT1-receptor blockade, by reducing circulating levels of ET-1 and those of some growth factors, may offer an advantage regarding the effect on hypertensive cardiovascular changes in human hypertension.

Gender and the systemic hypertension-snoring association: a questionnaire-based case-control study

Since the role of gender in the association between hypertension and snoring is unknown, we studied it while accounting for age and body mass index (BMI) as confounding variables. A questionnaire on snoring was administered to 90 hypertensive (HT) subjects (45 men and 45 women) and to 90 normotensive (NT) subjects matched for gender, age and BMI. As expected, snoring was more commonly reported by men than by women, but no significant difference was found between HT and NT men, irrespective of age. Conversely, heavy snoring was more frequently reported by HT than NT women; habitual snoring was more common among young (age < 50 years) HT than NT women; and heavy snoring was more common among older (age > 50 years) HT than NT women. These data suggest an effect of gender on the hypertension-snoring association: in men, snoring may be accounted for by age and BMI whether or not hypertension is present, whereas in women the natural history of snoring appears different and more severe in HT than in NT. Although the mechanism(s) responsible for the differences between men and women are obscure at present, gender may be an important variable in the systemic hypertension-snoring association.

Insulin, sodium-lithium countertransport, and microalbuminuria in hypertensive patients

Both microalbuminuria (>0.290 nmol/min [20 microg/min]) and high sodium-lithium countertransport (SLC) in diabetic or hypertensive humans are predictive of overt nephropathy and more aggressive cardiovascular complications, perhaps induced by insulin resistance. To analyze the relationships between microalbuminuria, SLC, microalbuminuria, and insulin in essential hypertension, we studied 90 hypertensive white patients, 25 of whom had microalbuminuria and 32 of whom were healthy. When urine sampling was completed for albuminuria determination, SLC was measured; all patients then underwent standard (75 g) oral glucose load to measure basal (0 minutes) and 2-hour glucose and insulin serum levels. Glucose-insulin ratio was used as insulin sensitivity index (ISI). In both hypertensive patients with normal microalbuminuria and those with pathological microalbuminuria, plasma insulin at 120 minutes was significantly higher than in control subjects. When the patients with pathological microalbuminuria were divided into thirds on the basis of their microalbuminuria, in the lower third, we found statistically significant less fasting insulin and higher basal ISI. SLC was higher in hypertensives than normotensives and, among hypertensives, higher in the subgroup with elevated microalbuminuria. In hypertensives, we found a weak but significant correlation between SLC and microalbuminuria, independent of insulin or ISI. The prevalence of high value of SLC (> or =0.383 mmol x L-1 x h-1) was significantly lower in hypertensives with normal rather than abnormal urinary albumin excretion. Our results indicate that in nondiabetic hypertensive whites, higher microalbuminuria is accompanied by signs of insulin resistance; moreover, a link exists between SLC and microalbuminuria, both predictive of aggressive complications of hypertension.