Efficacy, tolerability and influence on "quality of life" of nifedipine GITS versus amlodipine in elderly patients with mild-moderate hypertension.

OBJECTIVE: The main purpose of this study was to compare efficacy, tolerability and influence on quality of life (QOL) of nifedipine gastrointestinal therapeutic system (NI) 30-60 mg once a day vs amlodipine (AM) 5-10 mg once a day in elderly patients with mild-moderate hypertension. DESIGN: This was a randomized, double-blind, parallel-group, multicenter study. After a 2-week single-blind placebo run-in, patients were randomized to either NI 30 mg or AM 5 mg. Responders continued on the same dosage for 16 additional weeks, while non-responders were titrated to 60 mg NI or 10 mg AM. METHODS: Blood pressure was measured by mercury sphygmomanometer and efficacy equivalence of NI and AM tested by covariance analysis. Diastolic blood pressure (DBP) was the primary efficacy parameter, its baseline value being taken as covariate while centers effect and treatment interaction were included as fixed effects in the analysis model. The secondary efficacy variables systolic blood pressure (SBP) and scores for QOL were analyzed according to the same model. RESULTS: At the end of the study, overall mean DBPs, calculated as least-square means (LSMEANS), in the "by protocol" population were 87.5 mmHg for NI and 86.7 for AM (difference 0.8 mmHg with 90% CI -1.2 to 2.8 mmHg). In the "by intention to treat" (ITT) population LSMEANS were 87.6 mmHg for NI and 86.4 mmHg for AM (difference 1.2 mmHg with 90% CI -0.6 to 3.1 mmHg). SBP LSMEANS in the "by protocol" population were 147.7 mmHg for NI and 147.3 mmHg for AM (difference 0.3 mmHg, with 90% CI -3.7 to 4.3); corresponding values in the "by ITT" population were 148.0 mmHg for NI and 147.2 for AM (difference 0.8 mmHg, with 90% CI -2.8 to 4.6). Mean values for QOL parameters were not significantly different. A total of 173 episodes of adverse events were documented in 54 patients (26 NI and 28 AM), dropouts were 15 (20% of group) on NI and 21 (28%) on AM. CONCLUSIONS: NI 30-60 mg was shown to be as efficacious and safe as AM 5-10 mg in elderly patients with mild-moderate hypertension. QOL improved compared to baseline with no significant difference between the two drugs, thus confirming a positive class effect for calcium antagonists.

Cytosolic calcium and hemorheological patterns during arterial hypertension.

Hypertension can be considered as a progressive ischaemic syndrome interesting micro- and macrovasculature. In hypertensives it is possible to observe a link between an increase in peripheral resistance and blood viscosity, and a decrease in red blood cell (RBC) deformability. It is important to underline the link between the increase of blood viscosity, the decrease of RBC deformability and the cytosolic calcium level, which is related to the ischaemic syndrome in hypertension. The aim of this study was to evaluate the level of Ca++ and its possible correlation with hemorheological patterns during arterial hypertension. Two groups were studied: Group 1 consisted of 18 mild hypertensives (11 males and 7 pre-menopausal females, aged 39 +/- 3 years). This group was of medium risk according to WHO and ISH (1999) with no other pathologies apart from peripheral occlusive arterial disease II stage type A. Group 2 was made up of 14 healthy subjects (9 males and 5 females, aged 34 +/- 4 years). The intraerythrocytic cytosolic calcium was evaluated using a fluorescent marker FURA 2/AM (Calbiochem). The following hemorheological parameters were also assessed using the new Laser assisted Optical Rotational Red Cell Analyzer (LORCA) according to the Hardeman method (1994): RBC deformability-Elongation Index (EI), RBC aggregability- aggregation half time (t 1/2). The data obtained showed that compared to the control group the hypertensives had a significantly higher level of intraerythrocytic cytosolic calcium (p < 0.01), plus a significant decrease in EI and t 1/2 evaluated using LORCA. We also observed a significant correlation (p < 0.01) between an increase in Ca++ and a decrease in EI in the hypertensive patients. Moreover our study revealed a significant correlation between the increase in intraerythrocytic Ca++ and the t 1/2 decrease. The evaluation of the hemorheological patterns and cytosolic calcium could explain the impairment in peripheral perfusion and oxygenation in hypertensive patients and could provide a good model for a better evaluation and treatment of microvasculature perfusion in subjects with essential and complicated hypertension.

Endothelin-1-receptor-mediated responses in resistance vessels of young and adult spontaneously hypertensive rats.

OBJECTIVE: To assess whether primary changes in endothelin-1 (ET-1) receptor responsiveness or secondary vessel functional modifications could characterize the effects evoked by ET-1 in the mesenteric vascular bed (MVB) of prehypertensive 5-week-old and 12-week-old spontaneously hypertensive rats (SHRs). DESIGN AND METHODS: We used male 5-week-old and 12-week-old SHRs and sex- and age-matched Wistar-Kyoto (WKY) rats as controls. ET-1 receptor responsiveness was evaluated by ET-1 (0.04-2 micromol/l) concentration-response curves and repeated with indomethacin and BQ-123 (0.1-0.5 micromol/l), the latter a selective ETA receptor antagonist. ETB receptor responsiveness was tested by sarafotoxin S6c (1-100 nmol/l) and IRL-1620 (0.1-10 nmol/l) concentration-response curves, obtained in the noradrenaline-precontracted MVB. RESULTS: At 5 weeks of age, ET-1 induced a similar concentration-dependent contraction in SHRs and WKY rats, with an overlapping BQ-123 pA2 value (negative common logarithm of the antagonist that produces an agonist dose ratio of 2) in the two strains. Indomethacin was ineffective in both groups. Sarafotoxin S6c and IRL-1620 both evoked an ETB-mediated, significant relaxation, only in WKY rats. In 12-week-old SHRs, ET-1 evoked a markedly increased maximal effect compared with the response in WKY rats (P< 0.01); this was prevented by treatment with indomethacin. The BQ-123 pA2 value was higher in SHRs than in WKY rats (P< 0.01). Both sarafotoxin S6c and IRL-1620 evoked a significant concentration-dependent relaxation in WKY rats, which was not detected in SHR preparations. CONCLUSIONS: Our results could suggest that the different responses evoked by ET-1 in the MVB of SHRs during the onset of hypertension may be related partially to primary alterations in the ET-1 receptorial pattern and partially to the onset of high blood pressure, leading to an impairment in the haemodynamic balance.

Antihypertensive efficacy of manidipine and enalapril in hypertensive diabetic patients.

Recent studies showed that in diabetic hypertensive patients, administration of angiotensin-converting enzyme (ACE)-inhibitors or calcium antagonists can effectively lower blood pressure (BP) and prevent diabetes-related cardiovascular complications with no adverse metabolic effects. We sought to assess the antihypertensive and metabolic effects of the new dihydropyridine calcium antagonist manidipine (M) in patients with diabetes mellitus and essential hypertension as compared with the ACE inhibitor enalapril (E). After 3 weeks of placebo, 101 (62 men; age range, 34-72 years) hypertensives with type II diabetes mellitus were randomized to M 10-20 mg or E 10-20 mg, od, for 24 weeks. At the end of the placebo period and the active-treatment phase, BP was measured with a mercury sphygmomanometer (office, O) and over the 24 h by ambulatory (A) monitoring. ABP recordings were analyzed to obtain 24-h, day (6 a.m. to midnight), and night (midnight to 6 a.m.) average systolic (S) and diastolic (D) BP and heart rate (HR) values. Homogeneity of the antihypertensive effect over the 24 h was assessed by the smoothness index [SI: i.e., the ratio between the average of the 24 hourly BP changes after treatment and the corresponding standard deviation (the higher the SI, the more uniform is the BP control by treatment over the 24 h]. The O SBP and DBP were significantly (p < 0.01) and similarly reduced by M (16 +/- 10 and 13 +/- 6 mm Hg, n = 49) and E (15 +/- 10 and 13 +/- 6 mm Hg, n = 45). The percentage of patients whose O DBP was reduced < or = 85 mm Hg (i.e., the value indicated to be the optimal DBP goal in diabetic hypertensives) was similar for M (37%) and E (40%). The reduction of 24-h BP also was similar between M (n = 38) and E (n = 38) for both drugs (systolic, 6 +/- 11 and 8 +/- 10 mm Hg; diastolic, 5 +/- 8 and 5 +/- 7; NS, M vs. E). The antihypertensive effect was distributed in a similar homogeneous fashion throughout the dosing interval, as shown by the similar SI values (M, 0.6 +/- 1.2 for SBP and 0.6 +/- 0.9 for DBP; E, 0.6 +/- 0.8 for SBP and 0.5 +/- 0.7 for DBP; NS, M vs. E). O and A HR were unchanged by either treatment. Markers of glucose and lipid metabolism and renal function were not significantly modified by treatment both with M and with E. In the diabetic hypertensives, M was as effective and metabolically neutral as the ACE-inhibitor E.

Insulin resistance in essential hypertension: a psychophysiological approach to the "chicken and egg" question.

AIMS: High levels of plasma insulin have frequently been found in patients with high blood pressure. The causal role of insulin resistance in essential hypertension, however, is still debated. Epidemiological and clinical studies have not provided complete responses to the original pathophysiological speculations, while the suggestion that enhanced sympathetic tone may induce both insulin resistance and hypertension is gaining ground. DATA SYNTHESIS: Many studies indicate that the high sympathetic drive in hypertensive patients originates within the brain, while other studies show that insulin resistance is associated with reduced vasodilatory capacity and increased vasoconstrictive functional responses ascribed to endothelial impairment. The sympathetic overdrive and enhanced cardiovascular reactivity, detectable since the earliest stages of hypertension lead to endothelial damage and, hence, impair the vasodilatory response, peripheral blood flow and flow-dependent metabolism. Thus, the link between hyperinsulinemia and high blood pressure might lie in the vascular abnormalities secondary to elevated sympathetic tone and exaggerated hemodynamic stress response. CONCLUSIONS: Examination of the literature and the results of recent pilot studies of the stress systemic and regional hemodynamic reactivity in the present paper suggests that behavioral characteristics and cardiovascular stress responses play a pivotal role in determining the hyperinsulinemic state in hypertensive patients. High sympathetic tone, with consequent vascular impairment and altered functional responses, may be the primary event causing hyperinsulinemia and start very early in patients with high blood pressure. In turn, hyperinsulinemia further contributes to vascular damage and aggravates the metabolic and hypertensive disease.

Abnormal transport of inorganic phosphate in left ventricular mitochondria from spontaneously hypertensive rats.

INTRODUCTION: The aim of this study was to investigate the kinetic properties of inorganic phosphate (Pi) translocator in intact mitochondria isolated from the hypertrophied left ventricular tissue of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) at the ages of 5 and 24 weeks, before and after the development of hypertension. METHODS: The dependence of the Pi uptake rate on substrate concentration was measured in both absence and presence of mersalyl by spectroscopic techniques. RESULTS: Saturation characteristics were found (Km 250.0 +/- 25.0 and 15.0 +/- 1.5 microM for 5- and 24-week-old SHR, and 300.0 +/- 30.0 and 40.0 +/- 4.5 microM for WKY rat mitochondria, respectively, p < 0.05; Vmax 1.2 +/- 0.16 and 0.1 +/- 0.01 delta A/min x mg mitochondrial proteins for 5- and 24-week-old SHR, and 4.1 +/- 0.39 and 1.4 +/- 0.12 delta A/min x mg mitochondrial proteins for 5- and 24-week-old WKY rats, respectively, p < 0.05). When Pi carrier activity was measured using concentrations which are assumed to be in the cytosol under physiological conditions, Pi carrier velocity was 1.1 and 0.1 in SHR and 4.6 and 1.4 delta A/min x mg mitochondrial proteins in WKY, at 5 and 24 weeks, respectively. CONCLUSIONS: The significant decrease in the activity of the Pi carrier could imply that pressure overload is critical in SHR. Nevertheless, as decreased activity was found in SHR also at an early age when animals do not show stable increased blood pressure levels, we suggest that other factors might contribute to the abnormalities of Pi transport in mitochondria. An altered gene expression possibly related to a primary defect in this strain or, alternatively, to an abnormal regulation of protein synthesis might be proposed as additional factors affecting Pi carrier activity. The results of this study, together with previous data of the literature showing abnormalities in energy production mechanisms, allow us to hypothesize a profound rearrangement of energy metabolism at the mitochondrial level in this model of left ventricular hypertrophy and hypertension.

Extracellular matrix gene expression in the left ventricular tissue of spontaneously hypertensive rats.

The aim of this study was to investigate the extracellular matrix gene expression in the hypertrophied left ventricular tissue of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats, at early and mature ages. Interestingly, with age, a marked increase (+85% and +187% at 25 and 30 weeks of age, respectively, p < 0.01, vs 5 weeks) in matrix metalloproteinase-1 (MMP-1) mRNA levels in SHR and a progressive decrease (-50%, -70%, -78%, -70% at 10, 15, 25 and 30 weeks, respectively, p < 0.01, vs 5 weeks) in WKY were seen. Moreover, mRNA levels were significantly lower in SHR at 5 weeks. The analysis of mRNA expression for the tissue inhibitor of metalloproteinase-1 (TIMP-1) showed a significant increase in WKY (+44% and +44%, vs 15 and 25 weeks, respectively, p < 0.05), whereas there were no significant changes in SHR with development. At 30 weeks TIMP-1 mRNA levels were significantly reduced in SHR. Temporal trends of procollagen alpha1(I) and procollagen alpha1(III) mRNA levels were similar in both strains, but lower levels for procollagen alpha1(III) were found in SHR at 5 and 30 weeks. Although no significant differences were measured between the strains, mRNA levels for fibronectin were found decreased in WKY and increased in SHR with age. The results of the present study suggest an altered balance between collagen deposition and collagen degradation with development in this model of left ventricular hypertrophy and hypertension.

Functional characterization of endothelin receptors in hypertensive resistance vessels.

OBJECTIVE: The physiological and pathophysiological functions of endothelin-1 in modulating the regional blood flow of normal and spontaneously hypertensive rats (SHR) were studied in the perfused mesenteric vascular bed, a useful model for investigating resistance vessels. DESIGN AND METHODS: We used 12-week-old SHR and Wistar-Kyoto (WKY) rats. Endothelin A (ETA) receptor responsiveness was evaluated by endothelin-1 (0.2-2 mumol/l) concentration-response curves, and repeated in the presence of indomethacin and the ETA and endothelin B (ETB) receptor antagonists BQ-485 and BQ-788, respectively. ETB receptor responsiveness was tested by sarafotoxin S6c concentration-response curves, obtained in the noradrenaline-precontracted mesenteric vascular bed, and repeated after treatment with BQ-788 and after endothelial denudation. RESULTS: In both groups, endothelin-1 induced concentration-dependent contraction; SHR exhibited a markedly increased maximal effect compared with WKY rats (P < 0.01). BQ-485 produced a shift to the right for endothelin-1 concentration-response curves in both groups, with a higher pA2 (negative common logarithm of the antagonist that produces an agonist dose ratio of 2) value in SHR than in WKY rats (P < 0.01). The increase in the maximal effect produced by endothelin-1 in SHR was prevented by indomethacin, which also induced a significant increase in the endothelin-1 concentration producing the half-maximal response (EC50) in SHR (P < 0.05). Sarafotoxin S6c produced an ETB-dependent endothelium-mediated relaxant effect in WKY rats, which was not observed in SHR. CONCLUSIONS: The higher vasoconstriction induced by endothelin-1 in SHR may be related to a greater number of available ETA receptors, due to the presence of an ETA receptor subtype. This mechanism may be linked to the production of prostanoids that add to the direct endothelin-1-evoked vasoconstriction. These results, together with the lack of relaxation in response to sarafotoxin S6c in SHR, suggest that an imbalance in the endothelin-1 ability to induce both contraction and relaxation is present in SHR with sustained hypertension, manifesting as a greater contractile effect evoked in this strain.

Distinct and combined vascular effects of ACE blockade and HMG-CoA reductase inhibition in hypertensive subjects.

Hypercholesterolemia and hypertension are frequently associated with elevated sympathetic activity. Both are independent cardiovascular risk factors and both affect endothelium-mediated vasodilation. To identify the effects of cholesterol-lowering and antihypertensive treatments on vascular reactivity and vasodilative capacity, we studied 30 hypercholesterolemic hypertensive subjects. They received placebo for 4 weeks, either enalapril or simvastatin for 14 weeks, and, finally, both medications for an additional 14 weeks. Postischemic forearm blood flow (MFBF) and minimal vascular resistance (mFVR) were used as indices of vasodilative capacity and structural vascular damage, respectively. Total (resting-stress-recovery phases) cardiovascular (blood pressure [BP] and heart rate [HR]) and regional hemodynamic (FBF and FVR) reactivity to stressful stimuli were calculated as area-under-the-curve (auc) (valuextime). Compared with baseline levels, simvastatin reduced total (TOT-C) and LDL cholesterol (LDL-C) (1.27 mmol/L, P<0.001 and 1.33 mmol/L, P<0.001, respectively). Enalapril also reduced TOT-C and LDL-C (0.6 mmol/L, P<0.001 and 0.58 mmol/L, P<0.05, respectively). MFBF was increased substantially by both treatments (P<0.001). Enalapril had a greater effect (-1.7 arbitrary units (AU), P<0.001) than simvastatin (-0.6 AU, P<0.05) on mFVR. During stress, FBF increased more with enalapril (4.4 FBFxminutes, P<0.001) than with simvastatin (1.8 FBFxminutes, P<0.01). Conversely, FVR stress response was reduced more with enalapril (9.1 FVRxminutes, P<0.001) than with simvastatin (2.9 FVRxminutes, P<0.01). During combination treatment, a significant (0.001>P<0.05) additive effect on hypercholesterolemia, structural vascular damage, BP, and FVR was shown. The findings suggest that angiotensin-converting enzyme (ACE) inhibition induces a larger reduction than HMG-CoA reductase blockade in vascular reactivity and structural damage in hypercholesterolemic hypertensive subjects.

Hemorheology and tissue oxygenation in hypertensives with lipoidoproteinosis and peripheral occlusive arterial disease (POAD) treated with sulodexide and pravastatine and evaluated with laser assisted optical rotational red cell analyzer (LORCA) and transcutaneous oxymetry.

BACKGROUND: During arterial hypertension it is often possible to find other factors like lipoidoproteinosis and peripheral arterial disease (POAD), which can accentuate blood rheological abnormalities in hypertensive subjects. A group of hypertensives with lipoidoproteinosis (LP) and POAD were therefore examined to evaluate the relationship between these factors and blood rheological disorders and, if possible, to correct it. METHODS: We studied a group of 27 hypertensives with LP and POAD (15 males and 12 females in menopause for at least 1 year, aged 48 +/- 4 years), with WHO stage I hypertension, obesity (BMI = 30 +/- 2), stage II type "a" POAD, class 2 type "b" lipoidoproteinosis (acc. to Fredrick-son's classification) and hyperfibrinogenemia. All patients received oral medication with 500 lipidic units (ULS) sulodexide a day, 20 mg pravastatin o.d. orally, and were put on a low-salt and low-calorie diet (1400 kcal/day) during a follow-up of 60 days. Blood rheology status was evaluated before and after treatment (red blood cell--RBC--deformability and aggregability) using a new computerized instrument, which uses laser rays: the laser assisted optical rotational red cell analyzer (LORCA) (acc. to Hardeman) and RBC deformability using optical microscopy under immersion (acc. to Zipursky and Forconi). Transcutaneous oxymetry was also used to evaluate tissue oxygenation. RESULTS AND CONCLUSIONS: At the end of the study a significant improvement (p < 0.01) was noted in the blood rheological patterns of peripheral perfusion and tissue oxygenation. This underlined the positive influence of sulodexide with pravastatin in improving hemorheological patterns and modulating hypercholesterolemia and hyperfibrogenemia in hypertensives with POAD II "a" and LP 2 "b" and blood rheology disorders.

Management of antihypertensive treatment with Lisinopril: a chronotherapeutic approach.

Risk for cardiovascular events seems to be higher in the early morning, also as consequence of a rise in blood pressure (BP) values due to the characteristic circadian pattern of BP variability. Therefore, a suitable therapeutic BP control should be tightest during the early morning. On the basis of the ambulatory blood pressure monitoring (ABPM) studies, it has been previously demonstrated that the antihypertensive effect of once daily drug, generally administrated in the morning, decreases at the end of the dosing period. A chronotherapeutic approach to the management of hypertension (this field has been pourly investigated so far) would allow the assessment of the optimum timing of drug dosing, according to the circadian BP rhythm and to the chronorisk maps, in hypertensive patients affected by associated vascular pathologies. This would increase the therapeutic effects. The aim of this study was to assess BP changes due to ACE-inhibitor (Lisinopril 20 mg/die) once daily administration at three different times (8.00 AM, 4.00 PM, 10.00 PM), in order to optimise the dosing time. 40 subjects (mean age +/- SD: 45 +/- 10) affected by primary mild to moderate hypertension were submitted to ABPM for 24 hours, by means of Spacelabs 90207, before and after pharmacological treatment. Patients were randomised to take the drug at 8.00 AM, 4.00 PM or 10.00 PM, and they repeated ABPM every two months, by changing the dosing time. The chronobiological analysis showed: 1) a sensible decrease both in Systolic (S)BP and Diastolic (D)BP without affecting the circadian rhythm, in all evaluations; 2) a greater reduction of SBP and DBP from 6.00 AM to 11.00 AM, period in which cardiovascular risk is higher, after 10.00 PM dosing; 3) no other sensible reduction in SBP and DBP occurred after night administration as compared to that caused by other dosing times. Lisinopril administration at 10.00 PM. has been shown to be much more useful since, although BP circadian rhythm was unmodified, it protects hypertensive patients from both vascular chronorisk and Cruickshank effect (J-curve). Therefore, a chronobiologist antihypertensive treatment in order to increase the therapeutic effect already obtained with the traditional statistic methods.

Arterial hypertension and hemorheology. What is the relationship?

The strong relationship between arterial hypertension and hemorheological alteration present in all the vascular segments can be affirmed. These hemorheological changes are: an increase in the whole blood and plasma viscosity, in red blood cell (RBC) rigidity and aggregability and subsequently a decrease in oxygen delivery. Anyway, there are very interesting, still now unclear questions to be resolved: 1. Can arterial hypertension (with its vascular and cardiac remodeling) be the most relevant factor inducing alterations in the macro and the microrheology? 2. Can the altered hemorheology, above all in the microcircle, be one of the numerous causes of hypertension? 3. What is the influence of tissue oxygenation changes in these situations: are these changes or effects of alterations during hypertension? In the next years using new technologies we hope that these problems will be resolved indicating new ways to treat hypertensives and to present its related complications.

Red blood cell (RBC) deformability, RBC aggregability and tissue oxygenation in hypertension.

Arterial hypertension could be considered a progressive ischaemic syndrome interesting the macro and the microcirculation. In order to improve the clinical and therapeutic approach to the treatment of arterial hypertension, research has centered on blood flow to evaluate the different components and their very intricate relationships influencing the micro- and the macrocirculation. Of course the main problem is to study the link between the blood flow and the peripheral tissue oxygenation. During hypertension very important alterations in rheological, mechanical and biochemical characteristics of erythrocytes and of blood flow have been shown. It is very relevant the increase in blood viscosity, the decrease in red blood cell (RBC) deformability, the formation of RBC "rouleaux" and RBC aggregates. These hemorheological determinants can favour an increase of peripheral resistances and of arterial blood pressure, causing or worsening hypertension, a decrease in oxygen transport to tissue and peripheral perfusion, a decrease of the active exchange surface area in the microvasculature, especially in complicated hypertension. We have studied 320 patients: 123 with Essential Hypertension (EH) (M 59, F 64 aged 50 +/- 25 years); 81 with Secondary Hypertension (SH) without associated other pathologies influencing hemorheology (M 42, F 39 aged 48 +/- 20 years); 116 SH with other pathologies or conditions associated influencing hemorheology such as: diabetes, lipoidoproteinosis, obesity, smoking, HD, elderly, etc. (M 48, F 68 aged 46 +/- 20 years). Using a Laser-assisted Optical Rotational Red Cell Analyzer (LORCA) acc. to Hardeman (1994) we studied Elongation Index (EI) and aggregation kinetics of red blood cells in these patients. We also evaluated TcpO2 and TcpCO2 using a transcutaneous oxymeter (Microgas 7650, Kontron Instruments). In hypertensives we found a decrease in erythrocyte deformability (evaluated with EI), in erythrocyte aggregation time, a fibrinogenaemia increase, an increase of shear rate to disaggregate erythrocytes, a decrease in cellular oxygen delivery and tissue oxygenation, an impairment of microcirculation. These changes may be involved in the development of arterial hypertension and in its pathogenesis. These patterns also are more impaired in hypertensives with diabetes, lipoidoproteinosis, etc. These patterns are not related with the age of the patients but they are significantly and directly related (p < 0.01) with the patient hypertension-age. This could be a new way to realize a better treatment in hypertensives and a prevention of cardiovascular complications (i.e.: myocardial infarction, TIA, etc.).

Microvascular changes during laboratory stimuli and structural haemodynamic indices: the role of pulse pressure.

Office and ambulatory pulse pressure have been recognized as independent predictors of cardiovascular mortality and atherosclerosis in hypertensives as well as in normotensives. On the other hand, the vascular reactivity, in subjects with high pulsatile component of blood pressure, has not been studied yet. The purpose of our study was to identify the regional muscular hemodynamics and the cutaneous microvascular changes during laboratory stimuli in young adult very mild hypertensives with high pulse pressure. The cardiovascular (Finapres), the forearm vascular (plethysmography) and the microvascular cutaneous (laser-Doppler flowmetry and transcutaneous oximetry) responses to psychophysiological stimuli were measured. In addition, the hyperemic forearm vascular response to the ischaemic test was measured as haemodynamic index of vascular damage. We studied 15 very mild hypertensives with higher office pulse pressure and 15 patients with similar age, history of hypertension, metabolic parameters and systodiastolic blood pressure but lower pulse pressure values. Patients with high pulse pressure demonstrated reduced hyperemic response and increased residual vascular resistance at the forearm ischaemic test. They did not vary for all the parameters, except pulse pressure, during the baseline period but the total stress response, as residualized area-under-the-curve, was notably different. Patients with higher office pulse pressure demonstrated a significant increased heart rate, systolic and pulsatile blood pressure reactivity. On the contrary, they showed a reduced forearm and cutaneous blood flow response combined to a reduced transcutaneous tissutal oxygenation. The findings suggest that the increased pulsatile component of blood pressure might be associated to structural and functional vascular impairments since the very early stages of hypertension in young adults without metabolic disorders.

Hemorheology in complicated hypertension.

During essential and secondary arterial hypertension it is possible to observe changes in microcirculation perfusion associated with a reduction in tissue oxygenation due in part to hemorheological changes such as an increase in blood viscosity or the formation of the red blood cell "rouleaux" which favour an increase in peripheral resistance and can cause or worsen arterial hypertension. We studied 21 healthy subjects (11 male and 10 female aged 42 +/- 4) and 26 hypertensive subjects (14 male and 12 female aged 49 +/- 3). The patients were non smokers and non suffering from respiratory or haemathological pathologies. They were not undergoing antihypertensive or vasodilatory pharmaceutical treatment. The patients suffered from mild hypertension (II WHO) with Peripheral Occlusive Arterial Disease (POAD II "a" acc. to Leriche-Fontaine class.). The patients showed an increase in cholesterolaemia (6.42 +/- 0.81 mmol/l) and trygliceridaemia (2.73 +/- 0.09 mmol/l) at an average level. The patients were studied in standard conditions with a constant temperature of 22 degrees C. We measured SBP, DBP, MBP, and the HR. We also measured the elongation index (EI) (with shear stress range 0.30 to 30 pascals) using LORCA, acc. to Hardeman method (1994), in order to study the erythrocyte deformability and aggregation kinetics in dynamic condition. To evaluate deformability in static conditions we calculated the Erythrocyte Morphologic Index (EMI), acc. to Forconi method, via the bowl/discocyte ratio (for 100 red blood cells fixed in glutaraldehyde at 0.3% and observed with an optical microscope under immersion in glycerol). Peripheral oxygenation was taken transcutaneously (TcpO2). To establish the level of vascular disease we used the Regional Perfusion Index (RPI = TcpO2 foot/TcpO2 subclavean) and doppler guided Winsor Index (WI). The Student "t" test and linear regression were used for the statistical analysis. Our data confirm a reduction in peripheral tissue oxygenation in hypertensives especially if suffering from vascular disease which correlates significantly (p < 0.01) with a reduction in red blood cell deformability. This itself can increase peripheral resistances and favour the onset of hemorheological complications, at a cerebral-vascular level, which are frequent in hypertensives.

Hemorheological aspects in hypertensive menopausal smoker women treated with female hormones.

In postmenopausal hypertensive women (PostMHW) the erythrocyte deformability (ED) is reduced if compared with premenopausal hypertensive women (PreMHW). This might partially explain the increased incidence of cardiovascular diseases (CD) in hypertensive women after menopause. Moreover a positive correlation exists between estradiol and rheological patterns in women. If PostMHW smoke cigarettes, there is an important decrease in hemorheological parameters. On the other hand if PostMHW are submitted to an hormonal replacement therapy (HRT) they can show controversial results with an impairment if hemorheological parameters. The aim of this study was to evaluate the influence of smoking and HRT on PostMHW. We studied four groups of subjects: Group 1: PreMHW (10 F aged 35 +/- 3 years) non smokers; Group 2: PostMHW (8 F aged 45 +/- 2 years) non smokers; Group 3: PostMHW (14 F aged 48 +/- 4 years) smokers (20 cigarettes per day); Group 4: PostMHW (16 F aged 50 +/- 2 years) smokers (20 cigarettes per day) submitted to HRT. We evaluated Elongation Index of erythrocytes under torsion force of 30 pascals (EI--30 Pa) using a new computerized instrument Laser assisted Optical rotational Red Cell Analyzer (LORCA) (Mechatronics, Hoorn, NL) acc. to Hardeman (1994) and, also with the same LORCA, Aggregation Index (AI), t(1/2). We measured the transcutaneous oxygen partial pressure (TcpO2) in subclavicular standard area using a Transcutaneous Oximeter (Microgas 7650 Kontron Instruments with Combi Sensor) and total cholesterolaemia. In PostMHW our data showed a significant (p < 0.01) impairment of hemorheological patterns and tissue oxygenation if compared with PreMHW (Group 1). In Group 3 there is a significant (p < 0.01) decrease in EI, a significant (p < 0.01) increase in AI, a significant (p < 0.01) decrease in t(1/2) and TcpO2 if compared with Control Group 1 and Group 2. Finally a further significant (p < 0.01) impairment in hemorheology and tissue oxygenation showed Group 4. In conclusion, it seems necessary, that many studies will be performed to understand really protective action of HRT on cardiovascular diseases in PostMHW and it is necessary to suppress cigarette smoking to prevent cardiovascular complications in these patients.

Tissular oxygenation and erythrocyte deformability in haemodialyzed patients using different dialytic membranes.

We studied the effect of some dialytic membrane on tissular oxygenation (TO) and erythrocyte deformability (ED). Sixteen patients (10 M and 6 F, aged 59 +/- 12 years) have been submitted to bicarbonate dialysis (BD) and subdivided into four groups (GR) of 4 patients each: GR 1 (hemophan membrane, 35 BD), GR 2 (polyacrylonitrile, PAN AN 69, 42 BD), GR 3 (polysulphone, 38 BD) and GR 4 (polycarbonate, 37 BD). The TO has been detected with the transcutaneous oxygen pressure (Tc pO2) using a transcutaneous oxymeter and the ED has been evaluated with the EMI (Erythrocyte Morphometric Index), which results from the ratio between deformable erythrocytes (bowl shape) and rigid erythrocytes (discocyte shape), for every 100 red cells fixed in vitro with 0.3% glutaraldehyde. The ED was also evaluated using a laser instrument: Laser Optical Rotational Cell Analyser. During BD was observed a significant decrease of Tc pO2 in the 1st hour only in the 1st and 2nd GR and, in contrast with results obtained in the 3rd and 4th GR, in the same GRs the EMI showed a significant reduction of ED at the end of BD. Finally the LORCA results, showing a significant decrease of ED only in the 1st and 2nd GR, confirmed the data obtained with EMI. In conclusion, our study has suggested that hemophan and PAN AN 69 are less biocompatible than polysulphone and polycarbonate membranes according to effects on ED and TO.

ATP synthesis and export in heart left ventricle mitochondria from spontaneously hypertensive rat.

Use was made of mitochondria isolated from heart left ventricles of either spontaneously hypertensive or age-matched Wistar-Kyoto rats used as a control to find out whether hypertrophy (5-week-old rats) or hypertrophy/hypertension (24-week-old rats) can cause change in the mechanisms by which ATP is synthesised via ATP synthase and subsequently exported via the ADP/ATP translocator outside mitochondria. To do this, photometric measurements were made of the rate of ATP appearance in the extramitochondrial phase, which occurs as a result of ADP addition to mitochondria. In mitochondria from spontaneously hypertensive rats deficit of ATP production was found dependent on changes in the KmADP and Vmax values of both the ADP/ATP translocator and the ATP synthase. The ADP/ATP translocator was found to determine the rate of ATP production outside mitochondria in all the tested samples. In an initial investigation carried out to ascertain how cell ATP deficit can be counterbalanced, an increase in both adenylate kinase and creatine kinase activities was found in both hypertrophy and hypertrophy/hypertension. A possible increase in anaerobic glycolysis was also suggested by the increased lactate dehydrogenase activity.