Review of the molecular pharmacology of Losartan and its possible relevance to stroke prevention in patients with hypertension

Molecular mechanism of cognitive impairment associated with Parkinson's disease: A stroke perspective

Parkinson's disease (PD) is a common neurological illness that causes several motor and non-motor symptoms, most characteristically limb tremors and bradykinesia. PD is a slowly worsening disease that arises due to progressive neurodegeneration of specific areas of the brain, especially the substantia nigra of the midbrain. Even though PD has continuously been linked to a higher mortality risk in numerous epidemiologic studies, there have been significant discoveries regarding the connection between PD and stroke. The incidence of strokes such as cerebral infarction and hemorrhage is substantially associated with the development of PD. Moreover, cognitive impairments, primarily dementia, have been associated with stroke and PD. However, the underlying molecular mechanism of this phenomenon is still obscure. This concise review focuses on the relationship between stroke and PD, emphasizing the molecular mechanism of cognition deficit and memory loss evident in PD and stroke. Furthermore, we are also highlighting some potential drug molecules that can target both PD and stroke.

Synthesis of New Polyheterocyclic Pyrrolo[3,4-b]pyridin-5-ones via an Ugi-Zhu/Cascade/Click Strategy

A diversity-oriented synthesis (DOS) of two new polyheterocyclic compounds was performed via an Ugi-Zhu/cascade (N-acylation/aza Diels-Alder cycloaddition/decarboxylation/dehydration)/click strategy, both step-by-step to optimize all involved experimental stages, and in one pot manner to evaluate the scope and sustainability of this polyheterocyclic-focused synthetic strategy. In both ways, the yields were excellent, considering the high number of bonds formed with release of only one carbon dioxide and two molecules of water. The Ugi-Zhu reaction was carried out using the 4-formylbenzonitrile as orthogonal reagent, where the formyl group was first transformed into the pyrrolo[3,4-b]pyridin-5-one core, and then the remaining nitrile group was further converted into two different nitrogen-containing polyheterocycles, both via click-type cycloadditions. The first one used sodium azide to obtain the corresponding 5-substituted-1H-tetrazolyl-pyrrolo[3,4-b]pyridin-5-one, and the second one with dicyandiamide to synthesize the 2,4-diamino-1,3,5-triazine-pyrrolo[3,4-b]pyridin-5-one. Both synthesized compounds may be used for further in vitro and in silico studies because they contain more than two heterocyclic moieties of high interest in medicinal chemistry, as well as in optics due to their high π-conjugation.

Serum uric acid and atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) represents a significant health concern, due to the increased prevalence, morbidity, and mortality.

METHODS AND RESULTS

There is a growing body of evidence correlating serum uric acid (SUA) with cardiovascular diseases such as arterial hypertension and AF.

CONCLUSION

Thus, a question arises as to whether SUA levels have a role in the pathophysiology of AF development.

The effect of tripterygium glucoside tablet on pharmacokinetics of losartan and its metabolite EXP3174 in rats

Losartan and tripterygium glucoside tablet (TGT) are often simultaneously used for reducing urine protein excretion in clinic. However, it is unknown whether there is potential herb-drug interaction between losartan and TGT. The aim of this study was to investigate their potential herb-drug interaction, and clarify the mechanism of the effect of TGT on the pharmacokinetics of losartan and its metabolite EXP3174 in rats. The plasma concentrations of losartan and EXP3174 were determined by LC-MS, and the main pharmacokinetic parameters were calculated. The C_max , t_1/2 and AUC_(0-t) of losartan became larger after co-administration, while the C_max and AUC_(0-t) of EXP3174 became smaller, suggesting that TGT could influence the pharmacokinetics of losartan and EXP3174. The effects of TGT and its main components on the metabolic rate of losartan were further investigated in rat liver microsomes. Results indicated that TGT and its two main ingredients could decrease the metabolic rate of losartan. Therefore, it was speculated that TGT might increase the plasma concentration of losartan and decrease the concentration of EXP3174 by inhibiting the metabolism of losartan. The results could provide references for clinical medication guidance of losartan and TGT to avoid the occurrence of adverse reactions.

Neurovascular and Cognitive failure in Alzheimer's Disease: Benefits of Cardiovascular Therapy

Alzheimer's disease (AD) is a multifactorial and multifaceted disease for which we currently have very little to offer since there is no curative therapy, with only limited disease-modifying drugs. Recent studies in AD mouse models that recapitulate the amyloid-β (Aβ) pathology converge to demonstrate that it is possible to salvage cerebrovascular function with a variety of drugs and, particularly, therapies used to treat cardiovascular diseases such as hypercholesterolemia and hypertension. These drugs can reestablish dilatory function mediated by various endothelial and smooth muscle ion channels as well as nitric oxide availability, benefits that result in normalized brain perfusion. These cerebrovascular benefits would favor brain perfusion, which may help maintain neuronal function and, possibly, delay cognitive failure. However, restoring cerebrovascular function in AD mouse models was not necessarily accompanied by rescue of cognitive deficits related to spatial learning and memory. The results with cardiovascular therapies rather suggest that drugs originally designed to treat cardiovascular diseases that concurrently restore cerebrovascular and cognitive function do so through their pleiotropic effects. Specifically, recent findings suggest that these drugs act directly on brain cells and neuronal pathways involved in memory formation, hence, working simultaneously albeit independently on neuronal and vascular targets. These findings may help select medications for patients with cardiovascular diseases at risk of developing AD with increasing age. Further, they may identify molecular targets for recovering memory pathways that bear potential for new therapeutic avenues.

Nature of extracellular signal that triggers RhoA/ROCK activation for the basal internal anal sphincter tone in humans

The extracellular signal that triggers activation of rho-associated kinase (RhoA/ROCK), the major molecular determinant of basal internal anal sphincter (IAS) smooth muscle tone, is not known. Using human IAS tissues, we identified the presence of the biosynthetic machineries for angiotensin II (ANG II), thromboxane A2 (TXA2), and prostaglandin F2α (PGF2α). These end products of the renin-angiotensin system (RAS) (ANG II) and arachidonic acid (TXA2 and PGF2α) pathways and their effects in human IAS vs. rectal smooth muscle (RSM) were studied. A multipronged approach utilizing immunocytochemistry, Western blot analyses, and force measurements was implemented. Additionally, in a systematic analysis of the effects of respective inhibitors along different steps of biosynthesis and those of antagonists, their end products were evaluated either individually or in combination. To further describe the molecular mechanism for the IAS tone via these pathways, we monitored RhoA/ROCK activation and its signal transduction cascade. Data showed characteristically higher expression of biosynthetic machineries of RAS and AA pathways in the IAS compared with the RSM. Additionally, specific inhibition of the arachidonic acid (AA) pathway caused ~80% decrease in the IAS tone, whereas that of RAS lead to ~20% decrease. Signal transduction studies revealed that the end products of both AA and RAS pathways cause increase in the IAS tone via activation of RhoA/ROCK. Both AA and RAS (via the release of their end products TXA2, PGF2α, and ANG II, respectively), provide extracellular signals which activate RhoA/ROCK for the maintenance of the basal tone in human IAS.

Enhanced spectrophotometric determination of Losartan potassium based on its physicochemical interaction with cationic surfactant

In this study, a simple and sensitive spectrophotometric method was developed for determination of Losartan potassium (LST K), an angiotensin-II receptor (type AT1) antagonist, in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The physicochemical interaction of LST K with CTAB was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of LST K was studied at pH 7.4. The binding constant (Kb) and the partition coefficient (Kx) of LST K-CTAB were 1.62×10(5) M(-1) and 1.38×10(5); respectively. The binding of LST K to CTAB micelles implied a shift in drug acidity constant (ΔpKa=0.422). The developed method is linear over the range 0.5-28 μg mL(-1). The accuracy was evaluated and was found to be 99.79±0.509% and the relative standard deviation for intraday and interday precision was 0.821 and 0.963; respectively. The method was successfully applied to determine LST K in pharmaceutical formulations.

Impact of losartan and angiotensin II on the expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in rat vascular smooth muscle cells

The present study aimed to investigate the impact of losartan and angiotensin II (AngII) on the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1), secreted by rat vascular smooth muscle cells (VSMCs). Rat VSMCs were isolated and cultured in different concentrations of AngII and losartan for 24 h and western blot analysis and quantitative polymerase chain reaction were performed to observe the subsequent impact on the gene and protein expression of MMP-9 and TIMP-1. AngII was shown to promote the protein and gene expression of MMP-9 in VSMCs in a concentration-dependent manner. No effect was observed on the expression of TIMP-1, therefore, an increase in the MMP-9/TIMP-1 ratio was observed. Losartan was shown to be able to inhibit MMP-9 protein and gene expression in a concentration-dependent manner, whilst promoting an increase in TIMP-1 expression, thus decreasing the ratio of MMP-9/TIMP-1. The combined action of losartan and AngII resulted in the same directional changes in MMP-9 and TIMP-1 expression as observed for losartan alone. The comparison of AngII, losartan and the combinatory effect on the expression of MMP-9 and TIMP-1 in VSMCs indicated that losartan inhibited the effects of AngII, therefore reducing the MMP-9/TIMP-1 ratio, which may contribute to the molecular mechanism of losartan in preventing atherosclerosis. In atherosclerosis, the development of the extracellular matrix of plaque is closely correlated with the evolution of AS. The balance between MMPs and TIMPs is important in maintaining the dynamic equilibrium between the ECM, and the renin-angiotensin-aldosterone system, which is involved in the pathologenesis of AS, and in which AngII has a central role.

Association of phagocytic NADPH oxidase activity with hypertensive heart disease: a role for cardiotrophin-1?

Left ventricular hypertrophy (LVH) is an independent marker of mortality in hypertension. Although the mechanisms contributing to LVH are complex, inflammation and oxidative stress may favor its development. We analyzed the association of the phagocytic NADPH oxidase-mediated superoxide anion release and LVH in patients with essential hypertension and the role of cardiotrophin-1 (CT-1) and interleukin-6 (IL-6), cytokines implicated in cardiac growth. Blood pressure, echocardiography data, and serum CT-1 and IL-6 levels were obtained in 140 subjects: 18 normotensives without LVH, 42 hypertensives without LVH, and 80 hypertensives with LVH. The NADPH oxidase-dependent superoxide production was assessed by chemiluminescence in peripheral blood mononuclear cells. Peripheral blood mononuclear cells were stimulated with CT-1 in vitro. Superoxide anion production by peripheral blood mononuclear cells associated with LVH and correlated with the left ventricular mass index. Serum CT-1 and IL-6 levels, which associated with the left ventricular mass index, correlated with superoxide production. Serum CT-1 and IL-6 levels were correlated. CT-1 stimulated NADPH oxidase superoxide production in peripheral blood mononuclear cells, which resulted in an increased release of IL-6. Our results show that superoxide anion production by the phagocytic NADPH oxidase associates with hypertensive heart disease, being significantly enhanced in hypertensive patients with LVH. This may be attributable to the activation of the NADPH oxidase by CT-1 and the subsequent release of IL-6. The phagocytic NADPH oxidase may be a therapeutic target in hypertensive heart disease.

Adult genetic risk screening

Recent advances in genetic analysis especially DNA sequencing technology open a new strategy for adult disease prevention by genetic screening. Physicians presently treat disease pathology with less emphasis on disease risk prevention/reduction. Genetic screening has reduced the incidence of untreatable childhood genetic diseases and improved the care of newborns. The opportunity exists to expand screening programs and reduce the incidence of adult onset diseases via genetic risk identification and disease intervention. This article outlines the approach, challenges, and benefits of such screening for adult genetic disease risks.

Pre-treatment with curcumin enhances plasma concentrations of losartan and its metabolite EXP3174 in rats

The study was carried out in the Wistar rats to investigate the effect of curcumin pre-treatment on the pharmacokinetics of the hypertension-treating drug losartan and its metabolite EXP3174 following single oral administration. In the treatment group, rats were gavaged with losartan 10 mg/kg after repeat oral doses of curcumin (100 mg/kg, for 7 d), while rats in the control group were administrated only with the same dose losartan. The results showed that curcumin significantly increased the plasma concentrations of losartan and its metabolite EXP3174. The present study implicated the existence of herb-drug interaction between curcumin and losartan, and further evaluation of the possible interaction during curcumin administration needs to be considered.

Epidemiology, pathophysiology, and treatment of hypertension in ischaemic stroke patients

Stroke continues to be one of the leading causes of mortality and morbidity worldwide. There are 2 main types of stroke: ischaemic strokes, which are caused by obstruction of the blood vessels leading to or within the brain, and haemorrhagic strokes, which are induced by the disruption of blood vessels. Stroke is a disease of multifactorial aetiology that may develop as an end state in patients with serious vascular conditions--most notably, uncontrolled arterial hypertension--thereby necessitating the effective control of this risk factor to prevent stroke or its recurrence. This paper focuses specifically on the epidemiology and pathogenesis of ischaemic stroke mainly in chronically hypertensive patients and pays particular attention to the efficacy of a select group of routinely used major antihypertensive drugs (i.e., angiotensin-converting enzyme inhibitors, angiotensin II type 1 receptor blockers, and calcium channel blockers) in the treatment of strokes.

Losartan abolishes oxidative stress induced by intermittent hypoxia in humans

The aim of this study was to assess the role of the type 1 angiotensin II (AT(1)) receptor in the increase of oxidative stress and NO metabolism during a single 6 h exposure to intermittent hypoxia (IH). Nine healthy young men were exposed, while awake, to sham IH, IH with placebo medication, and IH with the AT(1) receptor antagonist, losartan, using a double-blind, placebo-controlled, randomized, crossover study design. In addition to blood pressure, oxidative stress, peroxynitrite activity, uric acid, global antioxidant status and the end-products of NO (NOx) metabolism were measured in plasma before and after 6 h of IH. Oxidative stress and peroxynitrite activity increased and NOx decreased during IH with placebo. In contrast, neither sham IH nor IH with losartan affected these parameters. With respect to each condition, blood pressure had the same profile as oxidative stress. These results demonstrate that blockade of AT(1) receptors prevented the increase in oxidative stress and peroxynitrite activity and the decrease in NO metabolism induced by IH. Finally, this study suggests that the renin-angiotensin system may participate in the overproduction of reactive oxygen species associated with IH by upregulation of the actions of angiotensin II.

Adrenal beta-arrestin 1 inhibition in vivo attenuates post-myocardial infarction progression to heart failure and adverse remodeling via reduction of circulating aldosterone levels

OBJECTIVES

We investigated whether adrenal beta-arrestin 1 (βarr1)-mediated aldosterone production plays any role in post-myocardial infarction (MI) heart failure (HF) progression.

BACKGROUND

Heart failure represents 1 of the most significant health problems worldwide, and new and innovative treatments are needed. Aldosterone contributes significantly to HF progression after MI by accelerating adverse cardiac remodeling and ventricular dysfunction. It is produced by the adrenal cortex after angiotensin II activation of angiotensin II type 1 receptors (AT₁Rs), G protein-coupled receptors that also signal independently of G proteins. The G protein-independent signaling is mediated by βarr1 and βarr2. We recently reported that adrenal βarr1 promotes AT₁R-dependent aldosterone production leading to elevated circulating aldosterone levels in vivo.

METHODS

Adrenal-targeted, adenoviral-mediated gene delivery in vivo in 2-week post-MI rats, a time point around which circulating aldosterone significantly increases to accelerate HF progression, was performed to either increase the expression of adrenal βarr1 or inhibit its function via expression of a βarr1 C-terminal-derived peptide fragment.

RESULTS

We found that adrenal βarr1 overexpression promotes aldosterone elevation after MI, resulting in accelerated cardiac adverse remodeling and deterioration of ventricular function. Importantly, these detrimental effects of aldosterone are prevented when adrenal βarr1 is inhibited in vivo, which markedly decreases circulating aldosterone after MI. Finally, the prototypic AT₁R antagonist losartan seems unable to lower this adrenal βarr1-driven aldosterone elevation.

CONCLUSIONS

Adrenal βarr1 inhibition, either directly or with AT₁R "biased" antagonists that prevent receptor-βarr1 coupling, might be of therapeutic value for curbing HF-exacerbating hyperaldosteronism.

Activation of MMP8 and MMP13 by angiotensin II correlates to severe intra-plaque hemorrhages and collagen breakdown in atherosclerotic lesions with a vulnerable phenotype

Angiotensin II (ATII)-mediated hypertension increases the risk for acute coronary events, which may be caused by augmented collagen degradation. Interstitial fibers of collagen type I in the plaque can be degraded by MMP8 and MMP13 specifically. Indeed high MMP8 levels have been correlated with ruptured plaques in patients. To study the contribution of ATII in plaque rupture, we evaluated its effect on MMP8 and MMP13 activity on the vulnerable lesions using an extravascular device that induces regions of pro-atherogenic shear stress in the carotid arteries of ApoE KO mice. This triggers the growth of lesions with a "vulnerable" macrophage-rich phenotype (referred to as upstream lesions) and lesions with a "stable" fibrotic phenotype (referred to as downstream lesions). ATII administration increased mean blood pressure, and increased the incidence of intra-plaque hemorrhages (IPH) from 30% to 73% of the animals in the upstream segments. The area of IPH was also increased by 5-fold. No IPHs were observed in the downstream lesions of the control group or the ATII group. In addition, ATII treatment doubled the size of upstream and downstream lesions. Upstream lesions in the ATII group were decreased in collagen content by 3-fold, contained 2-fold higher MMP8 and MMP13 levels, with a 2- and 3-fold increase in collagen type I degradation by MMP8 and MMP13 respectively compared to the upstream lesions in the control group. Gene expression analysis showed general increase in procollagens and TIMPs expression in response to ATII. However, ATII also decreased procollagen 5alpha3 expression in downstream lesions and decreased TIMP4 expression in upstream lesions. These data show that ATII promotes a "stable" fibrotic phenotype by inducing severe intra-plaque hemorrhages, characterized by increased degradation of interstitial collagen I via an MMP-mediated (MMP8 and MMP13) mechanism.

Effects of losartan on serum total and high-molecular weight adiponectin concentrations in hypertensive patients with metabolic syndrome

High-molecular weight (HMW) adiponectin may have the most biologic activity among several isoforms. We investigated long-term effects of losartan on serum concentrations of total and HMW adiponectin in hypertensive patients with metabolic syndrome (MS) by serial measurements over 6 months. Forty hypertensive patients first received 50 mg of losartan. Upward titration of the losartan dose was implemented to reach a target blood pressure of less than 140/90 mm Hg. Serum total adiponectin and HMW adiponectin were measured at study entry (baseline), the 3-month treatment time point, and the end of the 6-month period. Non-HMW adiponectin (ie, medium- and low-molecular weight adiponectin) was calculated as total adiponectin--HMW adiponectin. Diagnosis of MS was done by current standard criteria. In hypertensive patients without MS (n = 21), the serum total adiponectin increased from 9.8 +/- 5.4 microg/mL at baseline to 11.1 +/- 6.2 microg/mL at 6 months (P < .01). Furthermore, the serum total adiponectin was significantly higher at 6 months than at 3 months (P < .01). Serum HMW adiponectin also increased from 5.7 +/- 3.9 microg/mL at baseline to 6.6 +/- 4.4 microg/mL at 6 months (P < .01). In hypertensive patients with MS, the serum total adiponectin increased from 6.0 +/- 2.7 mug/mL at baseline to 6.7 +/- 3.3 microg/mL at 3 months and to 7.0 +/- 3.1 microg/mL at 6 months (P < .01 for both). Furthermore, the serum HMW adiponectin concentration was significantly higher at 6 months than at 3 months (P < .001). However, the serum non-HMW adiponectin concentration did not change during treatment in either group. In conclusion, serum total and HMW adiponectin concentrations increase after 6 months of losartan treatment in hypertensive patients, irrespective of the presence or absence of MS.

Site-specific cleavage of G protein-coupled receptor-engaged beta-arrestin. Influence of the AT1 receptor conformation on scissile site selection

The discovery of beta-arrestin-related approximately 46-kDa polypeptide in transfected cells and mouse hearts led us to examine angiotensin II type 1 receptor (AT(1)R)-dependent proteolytic cleavage of beta-arrestin(s). Receptor-ligand induced proteolysis of beta-arrestin(s) is novel, especially in the endocrine system, since proteolytic and/or splice variants of nonvisual arrestins are unknown. We used a strategy to retrieve AT(1)R-engaged isoforms of beta-arrestin 1 to confirm direct interaction of fragments with this G protein-coupled receptor and determine cleavage sites. Here we show that the angiotensin II-AT(1)R complex is associated with full-length and approximately 46-kDa beta-arrestin forms. Mass spectrometric analysis of the AT(1)R-associated short form suggested a scissile site located within the Arg(363)-Arg(393) region in the bovine beta-arrestin 1. Edman degradation analysis of a beta-arrestin 1 C-terminal fragment fused to enhanced green fluorescent protein confirmed the major cleavage to be after Phe(388) and a minor cleavage after Asn(375). Rather unexpectedly, the inverse agonist EXP3174-bound AT(1)R generated different fragmentation of bovine beta-arrestin 1, at Pro(276). The angiotensin II-induced cleavage is independent of inositol 1,4,5-trisphosphate- and Ca(2+)-mediated signaling pathways. The proteolysis of beta-arrestin 2 occurs, but the pattern is more complex. Our findings suggest that beta-arrestin cleavage upon AT(1)R stimulation is a part of the unraveling beta-arrestin-mediated G protein-coupled receptor signaling diversity.

Losartan and its interaction with copper(II): Biological effects

Losartan, the potassium salt of 2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl)biphenyl-4-yl)methyl]imidazol, is an efficient antihypertensive drug. The vibrational FTIR and Raman spectra of Losartan (its anionic and protonated forms) are discussed. In addition, the copper(II) complex of Losartan was obtained and characterized as a microcrystalline powder. The metal center is bound to the ligand through the nitrogen atoms of the tetrazolate moiety as determined by vibrational spectroscopy. The compound is a dimer with the metal centers in a tetragonal distorted environment but the presence of a monomeric impurity has been determined by EPR spectroscopy. The antioxidant properties of the complex (superoxide dismutase mimetic activity) and its effect on the proliferation and morphology of two osteoblast-like cells in culture are reported. The new compound exerted more toxic effects on tumoral cells than the copper(II) ion and Losartan.

An economic assessment of losartan-based versus atenolol-based therapy in patients with hypertension and left-ventricular hypertrophy: results from the Losartan Intervention For Endpoint reduction (LIFE) study adapted to The Netherlands

BACKGROUND

The Losartan Intervention For Endpoint reduction (LIFE) study was a randomized, doubleblind trial that compared the effects of losartan-based treatment with those of atenolol-based treatment on cardiovascular disease (CVD)-related morbidity and mortality in 9193 patients with hypertension and left-ventricular hypertrophy (LVH). Compared with atenolol, losartan reduced the combined risk for CVD-related morbidity and mortality by 13% (P = 0.021), and reduced the risk for stroke by 25% (P = 0.001), with comparable blood pressure control in both trial arms.

OBJECTIVE

The aim of this study was to analyze the cost-effectiveness of losartan compared with atenolol in the treatment of stroke from the Dutch health care perspective.

METHODS

Utilization of losartan and atenolol within the trial period (mean, 4.8 years) and an estimation of direct medical costs of stroke for The Netherlands were combined with estimates of reduction in life expectancy through stroke. Medication costs and stroke incidence during 5.5 years of patient follow-up were estimated separately, adjusted for the baseline degree of LVH and Framingham risk score. To estimate lifetime stroke costs, the cumulative incidence of stroke was multiplied by the lifetime direct medical costs attributable to stroke. All costs are in 2006 Dutch prices and discounted following the former (4% costs and effects) and new Dutch guideline (4% costs, 1.5% effects) for conducting pharmacoeconomic analyses.

RESULTS

With 4% discounting, prevention of stroke was associated with a gain of 3.7 life-years. As a consequence, losartan treatment was associated with 0.059 life-year gained (LYG) per patient treated with losartan. Losartan reduced stroke-related costs by 1,076 Euros (US $1,349) per patient. After inclusion of study medication cost, net cost per patient was 51 Euros ($64) higher for losartan than atenolol. The net cost per LYG was 864 Euros ($1083), which is below the Dutch pharmacoeconomic threshold of 20,000 Euros/LYG (~$25,000/LYG) for accepting interventions. The corresponding probability of a cost-effectiveness ratio below this Dutch threshold was 0.95. Discounting money and health following the new Dutch guideline resulted in an even more favorable cost-effectiveness for losartan.

CONCLUSIONS

Results from the present analysis suggest that, in The Netherlands, treatment with losartan compared with atenolol may well be a cost-effective intervention based on the reduced risk for stroke observed in the LIFE trial.

Prevention of interstitial fibrosis of renal allograft by angiotensin II blockade

We previously confirmed that losartan (LOS), an angiotensin-II (A-II) receptor blocker, diminished plasminogen activator inhibitor-1 (PAI-1) in cyclosporine (CsA)-treated renal graft recipients. Because PAI-1 is known to correlate with tissue fibrosis, we speculated that LOS would have the potential to prevent renal graft interstitial fibrosis. In this study, we focused our attention on the LOS-induced histopathologic changes in renal grafts. Out of 24 CsA-treated normotensive kidney transplanted patients, 8 began to take 25 to 50 mg/day of LOS soon after kidney transplantation (group 1). Eight did so 2 years after kidney transplantation (group 2). Eight received no ARBs as a control group (group 3). PAI-1 levels were monitored every 3 months for 2 years. Renal graft biopsy was performed on all participants, with informed consent, before and 2 years after the onset of this study. The biopsy specimens were stained with periodic acid-methenamine-silver (PAM)-Masson stain for light-microscopic examination. Fibrotic areas in each biopsy specimen were measured using the LUZEX-III image analyzing system. Statistical analysis was performed using Student's t-test. When we considered the pre-value of PAI-1 in each patient as 100%, the mean percent value of PAI-1 at 2 years after the onset of this study of groups 1, 2, and 3 were 81.5 +/- 10.3%, 90.1 +/- 12.5%, and 116.8 +/- 11.9%, respectively (P < .01 groups 1 and 2 vs group 3). Light-microscopic examination revealed less remarkable renal interstitial fibrosis among LOS administered groups. A-II blockade may be a key to prevent renal graft interstitial fibrosis.