| 1. |
- Hamrén, Bengt, et al.
(author)
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Pharmacokinetic-Pharmacodynamic Assessment of the Interrelationships Between Tesaglitazar Exposure and Renal Function in Patients With Type 2 Diabetes Mellitus
- 2012
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In: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 52:9, s. 1317-1327
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Journal article (peer-reviewed)abstract
- The effects of tesaglitazar on renal function (assessed as urinary clearance of 125I-sodium iothalamate or estimated by the modification of diet in renal disease formula) were studied in a 24-week open-label trial in type 2 diabetes mellitus patients randomized to daily doses of either tesaglitazar 2 mg or pioglitazone 45 mg. The aim of the analysis was to develop a population pharmacokinetic-pharmacodynamic model that could simultaneously describe the interrelationship between tesaglitazar exposure and reduction in renal function over time in patients with type 2 diabetes mellitus. The pharmacokinetic-pharmacodynamic model could adequately describe the interplay between tesaglitazar and glomerular filtration rate. A one-compartment model in which the apparent clearance was influenced by glomerular filtration rate characterized the pharmacokinetics of tesaglitazar. An indirect-response model was used for the slow time course of change in glomerular filtration rate, which decreased from 100 to 78 mL/min/1.73m2 after 12 weeks of treatment. All tesaglitazar-treated patients had a reduction in glomerular filtration rate, and available demographic variables could not explain differences in response. Patients treated with an angiotensin converting enzyme inhibitor were more sensitive to tesaglitazar and had larger glomerular filtration rate decrease compared to nontreated patients. Approximately 8 weeks after discontinuing treatment, mean glomerular filtration rate had returned towards baseline. The model and data give valuable insights into the dynamic changes in glomerular filtration rate over time.
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| 2. |
- Ekman, Bertil, et al.
(author)
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Individualized growth hormone substitution with normalized IGF-I levels does not stimulate the renin–angiotensin–aldosterone system
- 2002
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In: Clinical Endocrinology. - : Wiley. - 0300-0664 .- 1365-2265. ; 57:4, s. 473-479
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Journal article (peer-reviewed)abstract
- objective To study the effects of individualized recombinant GH substitution, aiming at normal circulating IGF-I levels, in GH-deficient adults on blood pressure, the renin–angiotensin–aldosterone system (RAAS), natriuretic peptides and urine free cortisol.study design Open study with control group. The patients were titrated in dose steps of 0·17 mg GH/day every 6–8 weeks until an IGF-I level around the mean + 1 SD was attained (Tmax). After another month the dose was reduced by 0·17 mg (minimum dose 0·17 mg/day) to produce IGF-I levels at or slightly below the age-related mean (Tend), and this maintenance dose was held constant for 6 months.subjects Eighteen patients (11 males and seven females) with GH deficiency participated. For comparison we also prospectively evaluated 17 matched control subjects.measurements Blood pressure and heart rate, circulating levels of IGF-I, plasma renin activity (PRA), immunoreactive active renin (IRR), angiotensin II, aldosterone, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and 24-h urine aldosterone and urine free cortisol levels.results Blood pressure was unchanged by GH substitution but heart rate increased significantly (P < 0·03). PRA was elevated on the highest GH dose (Tmax) compared to baseline (P < 0·01), but returned to baseline and levels of controls at Tend. Four patients developed transient oedema and tended to have higher PRA levels than the rest of the subjects (P = 0·09). The circulating levels of IRR, angiotensin II, aldosterone, BNP and 24-h urine aldosterone and urine free cortisol levels were unchanged by GH substitution, and did not differ from the levels in the control subjects. Baseline ANP levels in the patients were lower than in the controls (P < 0·01), but increased after GH substitution (P < 0·01) to levels found in with the controls.conclusions We found no major changes of the variables in the circulating renin–angiotensin–aldosterone system and a normalization of atrial natriuretic peptide when an individualized dose of GH was titrated to near-normal IGF-I levels.
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| 3. |
- Hallberg, Pär, et al.
(author)
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B2 bradykinin receptor (B2BKR) polymorphism and change in left ventricular mass in response to antihypertensive treatment : results from the Swedish Irbesartan Left Ventricular Hypertrophy Investigation versus Atenolol (SILVHIA) trial
- 2003
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In: Journal of Hypertension. - : Lippincott Williams & Wilkins. - 0263-6352 .- 1473-5598. ; 21:3, s. 621-4
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Hypertension is associated with a number of adverse morphologic and functional changes in the cardiovascular system, including left ventricular (LV) hypertrophy. Studies have demonstrated that bradykinin, through the B2 bradykinin receptor (B2BKR), mediates important cardiovascular effects that may protect against LV hypertrophy. Recently, a +9/-9 exon 1 polymorphism of the B2BKR was shown to be strongly associated with LV growth response among normotensive males undergoing physical training. We aimed to clarify whether the processes found in exercise-induced LV growth in normotensive people also occur in pathological LV hypertrophy. DESIGN AND METHODS: We determined the B2BKR genotype of 90 patients with essential hypertension and echocardiographically diagnosed LV hypertrophy, included in a double-blind study to receive treatment for 48 weeks with either the angiotensin II type 1 (AT1) receptor antagonist irbesartan or the beta1-adrenoceptor antagonist atenolol. RESULTS: B2BKR +9/+9 genotypes responded poorly in LV mass regression, independent of blood pressure reduction or treatment, as compared to the other genotypes (adjusted mean change in LV mass index = -10.0 +/- 4.6 versus -21.6 +/- 2.2 g/m2, P = 0.03). CONCLUSIONS: Our results suggest an impact of the B2BKR polymorphism on LV mass regression during antihypertensive treatment.
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| 4. |
- Hallberg, Pär, et al.
(author)
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The CYP2C9 genotype predicts the blood pressure response to irbesartan : results from the Swedish Irbesartan Left Ventricular Hypertrophy Investigation vs Atenolol (SILVHIA) trial
- 2002
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In: Journal of Hypertension. - : Lippincott Williams & Wilkins. - 0263-6352 .- 1473-5598. ; 20:10, s. 2089-2093
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Journal article (peer-reviewed)abstract
- BACKGROUND: The cytochrome P450 CYP2C9 enzyme (CYP2C9) metabolizes many clinically important drugs, for example, phenytoin, warfarin and the angiotensin II type 1 (AT(1)) receptor antagonists, losartan and irbesartan. Single nucleotide polymorphisms in the CYP2C9 gene result in the expression of three important variants, CYP2C9*1(wild-type), CYP2C9*2 and CYP2C9*3, the last two exhibiting reduced catalytic activity compared with the wild-type. The CYP2C9 genotype is known to determine sensitivity to and dose requirements for both warfarin and phenytoin, and also the rate of metabolism of losartan. However, its influence on clinical response to treatment with the AT(1) receptor antagonist, irbesartan, has not been investigated. OBJECTIVE: To determine whether the CYP2C9genotype influences the blood pressure-decreasing response to antihypertensive treatment with irbesartan. DESIGN AND METHODS: One hundred and two patients with essential hypertension and left ventricular hypertrophy were allocated randomly to groups to receive double-blind treatment with either irbesartan (n = 49) or the beta(1)-adrenergic receptor blocker, atenolol ( n= 53). Blood pressure was measured before and after 12 weeks of treatment. genotyping was performed using solid-phase minisequencing. RESULTS: The diastolic blood pressure (DBP) response differed in relation to the CYP2C9 genotype in patients given irbesartan: the reduction in patients with genotype CYP2C9*1/CYP2C9*1 (n = 33) was 7.5% and that with CYP2C9*1/CYP2C9*2 (n = 12) was 14.4% ( P= 0.036). A similar trend was seen for systolic blood pressure. In contrast, no relation was seen between the CYP2C9 genotype and blood pressure response to atenolol, a drug not metabolized via CYP2C9. CONCLUSIONS: The CYP2C9 genotype seems to predict the DBP response to irbesartan, but not to atenolol, in patients with essential hypertension.
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| 5. |
- Hallberg, Pär, et al.
(author)
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Transforming growth factor beta1 genotype and change in left ventricular mass during antihypertensive treatment : results from the Swedish Irbesartan Left Ventricular Hypertrophy Investigation versus Atenolol (SILVHIA)
- 2004
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In: Clinical Cardiology. - : Wiley. - 0160-9289 .- 1932-8737. ; 27:3, s. 169-73
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Journal article (peer-reviewed)abstract
- BACKGROUND: Angiotensin II, via the angiotensin II type 1 (AT1) receptor, may mediate myocardial fibrosis and myocyte hypertrophy seen in hypertensive left ventricular (LV) hypertrophy through production of transforming growth factor beta1 (TGF-beta1); AT1-receptor antagonists reverse these changes. The TGF-beta1 G + 915C polymorphism is associated with interindividual variation in TGF-beta1 production. No study has yet determined the impact of this polymorphism on the response to antihypertensive treatment. HYPOTHESIS: We aimed to determine whether the TGF-beta1 G + 915C polymorphism was related to change in LV mass during antihypertensive treatment with either an AT1-receptor antagonists or a beta1-adrenoceptor blocker. The polymorphism was hypothesized to have an impact mainly on the irbesartan group. METHODS: We determined the association between the TGF-beta1 genotype and regression of LV mass in 90 patients with essential hypertension and echocardiographically diagnosed LV hypertrophy, randomized in a double-blind study to receive treatment for 48 weeks with either the AT1-receptor antagonist irbesartan or the beta1-adrenoceptor blocker atenolol. RESULTS: Irbesartan-treated patients who were carriers of the C-allele, which is associated with low expression of TGF-beta1, responded with a markedly greater decrease in LV mass index (LVMI) than subjects with the G/G genotype (adjusted mean change in LVMI -44.7 g/m2 vs. -22.2 g/m2, p = 0.007), independent of blood pressure reduction. No association between genotype and change in LVMI was observed in the atenolol group. CONCLUSIONS: The TGF-beta1 G + 915C polymorphism is related to the change in LVMI in response to antihypertensive treatment with the AT1-receptor antagonist irbesartan.
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| 6. |
- Kurland, Lisa, et al.
(author)
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Angiotensin converting enzyme gene polymorphism predicts blood pressure response to angiotensin II receptor type 1 antagonist treatment in hypertensive patients
- 2001
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In: Journal of Hypertension. - : Lippincott Williams & Wilkins. - 0263-6352 .- 1473-5598. ; 19:10, s. 1783-1787
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To determine whether polymorphisms in the renin-angiotensin system can predict blood pressure-lowering response to antihypertensive treatment; more specifically, in response to treatment with irbesartan or atenolol. DESIGN AND METHODS: Eighty-six patients with hypertension were randomized to double-blind treatment with either the angiotensin II type 1 receptor antagonist irbesartan or the beta1 adrenergic receptor blocker atenolol and followed for 3 months. We analysed angiotensinogen T174M and M235T, angiotensin converting enzyme (ACE) I/D and angiotensin II type 1 receptor A1166C polymorphisms and related them to blood pressure reduction. RESULTS: The mean reductions in blood pressure were similar for both treatments. In the irbesartan group, individuals homozygous for the ACE gene I allele showed a greater reduction in diastolic blood pressure, exceeding those with the D allele (-18 +/- 11 SD versus -7 +/- 10 mmHg, P = 0.0096). This was not the case during treatment with atenolol, and the interaction term between type of treatment and ACE II genotype was significant (P = 0.0176). The angiotensinogen and angiotensin II type 1 receptor polymorhisms were not related to the response to treatment. CONCLUSIONS: ACE genotyping predicted the blood pressure-lowering response to antihypertensive treatment with irbesartan but not atenolol. Thus, specific genotypes might predict the response to specific antihypertensive treatment.
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| 7. |
- Malmqvist, Karin, et al.
(author)
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Regression of left ventricular hypertrophy in human hypertension with irbesartan
- 2001
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In: Journal of Hypertension. - : Ovid Technologies (Wolters Kluwer Health). - 0263-6352 .- 1473-5598. ; 19:6, s. 1167-1176
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Journal article (peer-reviewed)abstract
- BACKGROUND: The Swedish irbesartan left ventricular hypertrophy investigation versus atenolol (SILVHIA). OBJECTIVE: Angiotensin II induces myocardial hypertrophy. We hypothesized that blockade of angiotensin II subtype 1 (AT1) receptors by the AT1-receptor antagonist irbesartan would reduce left ventricular mass (as measured by echocardiography) more than conventional treatment with a beta blocker. DESIGN AND METHODS: This double-blind study randomized 115 hypertensive men and women with left ventricular hypertrophy to receive either irbesartan 150 mg q.d. or atenolol 50 mg q.d. for 48 weeks. If diastolic blood pressure remained above 90 mmHg, doses were doubled, and additional medications (hydrochlorothiazide and felodipine) were prescribed as needed. Echocardiography was performed at weeks 0, 12, 24 and 48. RESULTS: Baseline mean blood pressure was 162/ 104 mmHg, and mean left ventricular mass index was 157 g/m2 for men and 133 g/m2 for women. Systolic and diastolic blood pressure reductions were similar in both treatment groups. Both irbesartan (P < 0.001) and atenolol (P< 0.001) progressively reduced left ventricular mass index, e.g. by 26 and 14 g/m2 (16 and 9%), respectively, at week 48, with a greater reduction in the irbesartan group (P = 0.024). The proportion of patients who attained a normalized left ventricular mass (i.e. < or = 131 g/m2 for men and < or = 100 g/m2 for women) tended to be greater with irbesartan (47 versus 32%, P = 0.108). CONCLUSIONS: Left ventricular mass was reduced more in the irbesartan group than in the atenolol group. These results suggest that blocking the action of angiotensin II at AT1-receptors may be an important mechanism, beyond that of lowering blood pressure, in the regulation of left ventricular mass and geometry in patients with hypertension.
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| 8. |
- Öhman, K. Peter
(author)
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The kallikrein-kinin system in primary hypertension : dynamics of circulating components of the kallikrein-kinin system in relation to the renin-angiotensin-aldosterone system
- 1997
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Doctoral thesis (other academic/artistic)abstract
- Kinins are potent vasodilatory and blood pressure lowering peptides, with additional effects on renal handling of electrolytes and water. The kallikrein-kinin system consists of two separate entities, one confined to the circulation and the other to both tissues and the circulation. The role of the plasma system and the circulating part of the tissue system in circulatory homeostasis and electrolyte and metabolism is unclear, as well as the pathogenetic involvement of these systems in primary hypertension.The aims of the studies were to investigate the possible participation of the plasma kallikrein~ kinin system and the circulating components of the tissue kallikrein-kinin system in the regulation of blood pressure, electrolyte and water balance; possible differences between normotensive and primary hypertensive subjects with respect to these systems; relations between the kallikrein-kinin systems and the renin angiotensin-aldosterone system; evidence of regulated release of prorenin and the possible participation of the kallikrein-kinin systems in the conversion of prorenin to renin.Twentyseven patients with primary hypertension and 16 normotensive control subjects were given furosemide 80 mg p.a. in the first study. In the following 3 studies 15 hypertensive and 15 normotensive subjects participated. Graded i.v. infusion of angiotensin 11 during 3h, i.v. infusion of 2000ml 0.9% sodium chloride during 4h, and fludrocortisone 0.2 mg o.d. p.a. during 7 days were administered in separate protocol.1. Plasma prekallikrein levels did not differ between normotensive and hypertensive subjects. Furosemide increased plasma prekallikrein, angiotensin II had no effect and sodium chloride infusion and fludrocortisone administration reduced plasma prekallikrein. 2. Tissue kallikrein in plasma did not change during these experiments. 3. There were minute differences between normotensive and hypertensive subjects in the activation of both the plasma and the tissue kallikrein-systems and in their relation to blood pressure levels and renal sodium and water handling. 4. Alterations of prorenin levels in plasma evoked by changes in blood pressure, angiotensin II levels, electrolyte and water balance were parallel with those of renin and without any signs of separate specific regulatory mechanisms. 5. There were no signs that the plasma or circulating tissue kallikrein-kinin system participated in the conversion of prorenin to renin. 6. There were no clear functional relations between endogenous mineralocorticoids and circulating tissue kalikrein or plasma prekallikrein.In conclusion: The data demonstrate alterations in the activity of the plasma kallikrein-kinin system, related to electrolyte and volume balance; differences between normotensive and hypertensive subjects, the pathophysiological relevance of which remains to be elucidated; minor differences in the reactivity of circulating tissue kallikrein in hypertensive subjects, but no obvious participation of the circulating components of the tissue system. Hypertensives have higer renin/prorenin ratio there are no signs of specific regulation of prorenin release or participation of circulating kallikreins in the conversion of prorenin to renin. Some of these differences may have relevance to the abnormal blood pressure levels in patients with primary hypertension.
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