Clinical trial NCT00155064: Kallikrein-kinin (KKS) and Renin-angiotensin-aldosterone System (RAAS) in Primary Aldosteronism
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE4
Conditions: Hyperaldosteronism
Keywords: Primary aldosteronism
kallikrein
aldosterone
captopril
Lead sponsor: National Taiwan University Hospital
Sponsor class: OTHER
First posted: 2005-09-12
Enrollment: 100
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: DIAGNOSTIC

Brief summary: The tissue kallikrein-kinin (KKS) and renin-angiotension-aldosterone system (RAAS) had been implicated in regulating blood pressure and electrolyte homeostasis. Both of the KKS and RAAS may work coordinately to regulate salt metabolism, local blood flow. Thus, we conducted this study to elucidate, first, whether some alterations in components of the kallikrein-kinin system could do effect on aldosterone secretion.

Previous study has shown the post captopril plasma aldosterone concentration (PAC)/ plasma rennin activity (PRA) ration (ARR) was a reliable method for diagnosis of primary aldosteronism (PA). The ARR change by angiotensin II receptor blockade was reported to be significantly higher than that by ACE inhibitor. This study assessed whether angiotensin II receptor blockade offers any additional advantage in the diagnosis of PA. Clinically we evaluated the sensitivity and specificity of captopril (angiotensin-converting enzyme inhibition) and losartan (angiotensin II type 1 receptor blocker) test in PA patient. This interaction mechanism, in term, could further explain the interaction of KKS and RAAS.

Detailed description: Hypertension affects 20% to 25% of adult population. Most patients are diagnosed as having essential or primary hypertension. Up to 10% to 15 % have an identifiable cause and many of those have an adrenal basis \[Miroslava H. et al., 2002\]. The tissue kallikrein-kinin (KKS) and renin-angiotension-aldosterone system (RAAS) had been implicated in regulating blood pressure and electrolyte homeostasis. Recent studies in humans indicate that the vasodilator tissue KKS, the counterpart of the tissue RAAS, is also expressed in the adrenal gland. The adrenal gland regulates sodium and water excretion and reabsorption through the release of aldosterone and corticosterone. Previous study reveals an anatomical linkage between the tissue KKS and sodium and water metabolism. Both of the KKS and RAAS may work coordinately to regulate salt metabolism, local blood flow. In contrast, although many investigators have supported the notion that Ang II and BK physiologically antagonize each other's effects on blood pressure, there are many instances where the two peptides exert common actions. For example, the Bradykinin also stimulates aldosterone release from adrenocortical cells through B2 receptors. Furthermore, the AT1 receptor and the bradykinin (B2) receptor form stable heterodimers, the two major signaling proteins triggered by AT1. In vitro studies (Margolius 1995) have shown that kallikrein acts as a prorenin-activating enzyme, and that tissue kallikrein can generate angiotensin II.

However, the interactions between both systems are complex and not always simply antagonistic. The interactions of the two systems on aldosterone secretion are not examined Thus, we conducted this study to elucidate, first, whether some alterations in components of the kallikrein-kinin system could do effect on aldosterone secretion.

Our study provides evidence that bradykinin contributes substantially to the aldosterone secretion with or without the effects of angiotensin. The data also could confirm whether ATR2-Bradykinin-B2-aldosterone really works. We want to realize the expression of angiotensin and bradykinin in the adrenal gland and hypertension related to these systems.

Previous study has showed the post captopril plasma aldosterone concentration (PAC)/ plasma rennin activity (PRA) ration (ARR) was a reliable method for diagnosis of primary aldosteronism (PA). The ARR change by angiotensin II receptor blockade was reported to be significantly higher than that by ACE inhibitor. This study assessed whether angiotensin II receptor blockade offers any additional advantage in the diagnosis of PA. Clinically we evaluated the sensitivity and specificity of captopril (angiotensin-converting enzyme inhibition) and losartan (angiotensin II type 1 receptor blocker) test in PA patient. This interaction mechanism, in term, could further explain the interaction of KKS and RAAS.

Eligibility criteria: Inclusion Criteria:

Patients with hypertension admitted for the diagnosis of primary aldosteronism

Exclusion Criteria:

Pregnant or lactating women. (Pre-menopause women, capable of bearing children will undergo pregnancy test), hypertension without discontinuous b-blocker, ACEI or ARB for more than 10 days.

Primary outcomes:
measure: Diagnosis of primary aldosteronism
Secondary outcomes:
measure: Subgroup analysis of primary aldosteronism
Other outcomes:
Locations:
city: Taipei
country: Taiwan
facility: National Taiwan University Hospital
Study officials:
affiliation: National Taiwan University Hospital
name: Kwan-Dun Wu, Md, PhD
role: STUDY_CHAIR
affiliation: National Taiwan University Hospital
name: Vin-Cent Wu, MD
role: STUDY_DIRECTOR
References:
citation: Agharazii M, Douville P, Grose JH, Lebel M. Captopril suppression versus salt loading in confirming primary aldosteronism. Hypertension. 2001 Jun;37(6):1440-3. doi: 10.1161/01.hyp.37.6.1440.
citation: Dendorfer A, Wolfrum S, Dominiak P. Pharmacology and cardiovascular implications of the kinin-kallikrein system. Jpn J Pharmacol. 1999 Apr;79(4):403-26. doi: 10.1254/jjp.79.403.
citation: Hesse B, Rasmussen S, Lund JO, Christensen P, Damkjaer Nielsen M. Urinary excretion of kallikrein before and after operation for aldosterone-producing adenoma. Acta Med Scand. 1985;217(5):501-5. doi: 10.1111/j.0954-6820.1985.tb03253.x.