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Golani T, Bleier J, Kaplan A, Hod T, Sharabi Y, Leibowitz A, Grossman E, Shlomai G. A 120-Minute Saline Infusion Test for the Confirmation of Primary Aldosteronism: A Pilot Study. Am J Hypertens 2024; 37:415-420. [PMID: 38374690 DOI: 10.1093/ajh/hpae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/12/2024] [Accepted: 02/09/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND The saline infusion test (SIT) to confirm primary aldosteronism requires infusing 2 L of normal saline over 240 minutes. Previous studies raised concerns regarding increased blood pressure and worsening hypokalemia during SIT. We aimed to evaluate the diagnostic applicability of a SIT that requires 1 L of saline infusion over 120 minutes. METHODS A cross-sectional study, including all patients in a large medical center who underwent SIT from 1 January 2015 to 30 April 2023. Blood samples were drawn for baseline renin and aldosterone (t = 0) after 2 hours (t = 120 min) and after 4 hours (t = 240 min) of saline infusion. We used ROC analysis to evaluate the sensitivity and specificity of various aldosterone cut-off values at t = 120 to confirm primary aldosteronism. RESULTS The final analysis included 62 patients. A ROC analysis yielded 97% specificity and 90% sensitivity for a plasma aldosterone concentration (PAC) of 397 pmol/L (14 ng/dL) at t = 120 to confirm primary aldosteronism, and an area under the curve of 0.97 (95% CI [0.93, 1.00], P < 0.001). Almost half (44%) of the patients did not suppress PAC below 397 pmol/L (14 ng/dL) at t = 120. Of them, only one (4%) patient suppressed PAC below 276 pmol/L (10 ng/dL) at t = 240. Mean systolic blood pressure increased from 140.1 ± 21.3 mm Hg at t = 0 to 147.6 ± 14.5 mm Hg at t = 240 (P = 0.011). CONCLUSIONS A PAC of 397 pmol/L (14 ng/dL) at t = 120 has high sensitivity and specificity for primary aldosteronism confirmation.
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Affiliation(s)
- Tiran Golani
- Department of Internal Medicine D and Hypertension Unit, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
- Department of Medicine, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Jonathan Bleier
- Department of Internal Medicine D and Hypertension Unit, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
- Department of Medicine, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Alon Kaplan
- Department of Internal Medicine D and Hypertension Unit, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
- Department of Medicine, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Tammy Hod
- Department of Medicine, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Department of Medicine, Renal Transplant Center, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
- Nephrology Department, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
| | - Yehonatan Sharabi
- Department of Internal Medicine D and Hypertension Unit, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
- Department of Medicine, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Avshalom Leibowitz
- Department of Internal Medicine D and Hypertension Unit, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
- Department of Medicine, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Ehud Grossman
- Department of Medicine, Adelson School of Medicine, Ariel University, Ariel, Israel
| | - Gadi Shlomai
- Department of Internal Medicine D and Hypertension Unit, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
- Department of Medicine, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Department of Medicine, The Institute of Endocrinology, Diabetes, and Metabolism, the Chaim Sheba Medical Center, Tel-Hashomer, Israel
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Manosroi W, Williams GH. Genetics of Human Primary Hypertension: Focus on Hormonal Mechanisms. Endocr Rev 2019; 40:825-856. [PMID: 30590482 PMCID: PMC6936319 DOI: 10.1210/er.2018-00071] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 09/07/2018] [Indexed: 02/06/2023]
Abstract
Increasingly, primary hypertension is being considered a syndrome and not a disease, with the individual causes (diseases) having a common sign-an elevated blood pressure. To determine these causes, genetic tools are increasingly employed. This review identified 62 proposed genes. However, only 21 of them met our inclusion criteria: (i) primary hypertension, (ii) two or more supporting cohorts from different publications or within a single publication or one supporting cohort with a confirmatory genetically modified animal study, and (iii) 600 or more subjects in the primary cohort; when including our exclusion criteria: (i) meta-analyses or reviews, (ii) secondary and monogenic hypertension, (iii) only hypertensive complications, (iv) genes related to blood pressure but not hypertension per se, (v) nonsupporting studies more common than supporting ones, and (vi) studies that did not perform a Bonferroni or similar multiassessment correction. These 21 genes were organized in a four-tiered structure: distant phenotype (hypertension); intermediate phenotype [salt-sensitive (18) or salt-resistant (0)]; subintermediate phenotypes under salt-sensitive hypertension [normal renin (4), low renin (8), and unclassified renin (6)]; and proximate phenotypes (specific genetically driven hypertensive subgroup). Many proximate hypertensive phenotypes had a substantial endocrine component. In conclusion, primary hypertension is a syndrome; many proposed genes are likely to be false positives; and deep phenotyping will be required to determine the utility of genetics in the treatment of hypertension. However, to date, the positive genes are associated with nearly 50% of primary hypertensives, suggesting that in the near term precise, mechanistically driven treatment and prevention strategies for the specific primary hypertension subgroups are feasible.
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Affiliation(s)
- Worapaka Manosroi
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.,Division of Endocrinology and Metabolism, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Gordon H Williams
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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Shukri MZ, Tan JW, Manosroi W, Pojoga LH, Rivera A, Williams JS, Seely EW, Adler GK, Jaffe IZ, Karas RH, Williams GH, Romero JR. Biological Sex Modulates the Adrenal and Blood Pressure Responses to Angiotensin II. Hypertension 2018; 71:1083-1090. [PMID: 29686001 DOI: 10.1161/hypertensionaha.117.11087] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/07/2017] [Accepted: 03/13/2018] [Indexed: 12/25/2022]
Abstract
The relationship between biological sex and aldosterone on blood pressure (BP) is unclear. We hypothesized that sex would modify the interaction between aldosterone and vascular responses to salt intake and angiotensin II (AngII). To test this hypothesis, in 1592 subjects from the well-controlled Hypertensive Pathotype cohort, we compared responses of women and men to chronic (BP and aldosterone levels in response to dietary salt) and acute (BP, renal plasma flow, and aldosterone responses to AngII infusion) manipulations. Women had a 30% higher salt sensitivity of BP than men (P<0.0005) regardless of age or hypertension status, a greater BP response to AngII, and a 15% greater aldosterone response to AngII on both restricted and liberal salt diets (P<0.005). Furthermore, there was an interaction (P=0.003) between sex and aldosterone on BP response to AngII. Women also had a greater (P<0.01) increment in renal plasma flow in response to AngII than men. To assess potential mechanisms for this sex effect, we compared aldosterone responses to AngII or potassium from rat zona glomerulosa cells and observed greater aldosterone production in female than male zona glomerulosa cells basally and in response to both agonists (P<0.0001). In a rodent model of aldosterone-mediated cardiovascular disease induced by increased AngII and low NO, circulating aldosterone levels (P<0.01), myocardial damage (P<0.001), and proteinuria (P<0.05) were greater in female than male rats despite having similar BP responses. Thus, increased aldosterone production likely contributes to sex differences in cardiovascular disease, suggesting that women may be more responsive to mineralocorticoid receptor blockade than men.
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Affiliation(s)
- Mohammad Zaki Shukri
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Jia Wei Tan
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Worapaka Manosroi
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Luminita H Pojoga
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Alicia Rivera
- and Division of Nephrology, Department of Medicine, Vascular Biology Research Center, Beth Israel Deaconess Medical Center (A.R.)
| | - Jonathan S Williams
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Ellen W Seely
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Gail K Adler
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Iris Z Jaffe
- Harvard Medical School, Boston, MA; and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J., R.H.K.)
| | - Richard H Karas
- Harvard Medical School, Boston, MA; and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J., R.H.K.)
| | - Gordon H Williams
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
| | - Jose R Romero
- From the Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital (M.Z.S., J.W.T., W.M., L.H.P., J.S.W., E.W.S., G.K.A., G.H.W., J.R.R.)
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Spradling-Reeves KD, Shade RE, Haywood JR, Cox LA. Primate response to angiotensin infusion and high sodium intake differ by sodium lithium countertransport phenotype. ACTA ACUST UNITED AC 2017; 11:178-184. [PMID: 28238630 DOI: 10.1016/j.jash.2017.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/05/2017] [Accepted: 01/24/2017] [Indexed: 11/18/2022]
Abstract
An increased level of sodium-lithium countertransport (SLC) activity has been associated with salt-sensitive hypertension. Previous findings have suggested that dysregulation of the renin-angiotensin-aldosterone system (RAAS) may be involved in the mechanism linking elevated SLC activity and hypertension. Therefore, baboons with different levels of SLC activity were given two diets differing in sodium content, with and without an angiotensin II (ANG II) infusion, to investigate the relationship between SLC activity, the RAAS, and physiological regulation by sodium. Although we anticipated that high SLC activity would be associated with inappropriate function of the RAAS and greater arterial pressure sensitivity to dietary sodium and ANG II and that low SLC activity would be associated with the least BP sensitivity, we found that the low SLC phenotype correlated with BP sensitivity similar to the high SLC phenotype, and the normal SLC phenotype showed the least BP sensitivity to dietary sodium and ANG II.
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Affiliation(s)
| | - Robert E Shade
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Joseph R Haywood
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| | - Laura A Cox
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA; Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
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Elijovich F, Weinberger MH, Anderson CAM, Appel LJ, Bursztyn M, Cook NR, Dart RA, Newton-Cheh CH, Sacks FM, Laffer CL. Salt Sensitivity of Blood Pressure: A Scientific Statement From the American Heart Association. Hypertension 2016; 68:e7-e46. [PMID: 27443572 DOI: 10.1161/hyp.0000000000000047] [Citation(s) in RCA: 326] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Damkjaer M, Jensen PH, Schwämmle V, Sprenger RR, Jacobsen IA, Jensen ON, Bie P. Selective renal vasoconstriction, exaggerated natriuresis and excretion rates of exosomic proteins in essential hypertension. Acta Physiol (Oxf) 2014; 212:106-18. [PMID: 25041901 DOI: 10.1111/apha.12345] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 04/21/2014] [Accepted: 07/08/2014] [Indexed: 01/26/2023]
Abstract
AIM In essential hypertension (EH), the regulation of renal sodium excretion is aberrant. We hypothesized that in mild EH, (i) abnormal dynamics of plasma renin concentration (PRC) and atrial natriuretic peptide (ANP) are responsible for the exaggerated natriuresis, and (ii) exosomic protein patterns reflect the renal tubular abnormality involved in the dysregulation of sodium excretion. METHODS After 2-week drug washout and 4-day diet, systemic and renal hemodynamics, cardio-renal hormones, glomerular filtration and renal excretion were studied in male patients during saline loading (SL). Excretion rates of exosome-related urinary proteins including apical membrane transporters were determined by proteomics-based methods. RESULTS In patients, baseline renal vascular conductance was reduced (-44%, P < 0.001), but non-renal vascular conductances were normal while PRC was reduced and ANP elevated (both P < 0.01). SL induced exaggerated natriuresis and reduced PRC (P < 0.01), at normal suppression rate. SL increased arterial pressure in patients (+11 mmHg, P < 0.001), but not in controls; however, during time control, patients showed identical increases (+10 mmHg, P < 0.005) apparently dissociating arterial pressure from natriuresis. At baseline, excretion rates of 438 proteins ranged from 0.07 to 49.8 pmol (mmol creatinine)(-1); 12 proteins were found in all subjects, and 21 proteins were found in two or more patients, but not in controls. In patients, the excretion rate of retinoic acid-induced gene 2 protein was reduced, and excretion rates of other proteins showed increased variances compatible with pathophysiological and clinical applicability. CONCLUSION Essential hypertension patients exhibit selective renal vasoconstriction and individually varying excretion rates of several exosome-related proteins. Hormonal changes, rather than arterial pressure, seem to cause exaggeration of natriuresis.
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Affiliation(s)
- M. Damkjaer
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
| | - P. H. Jensen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - V. Schwämmle
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - R. R. Sprenger
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - I. A. Jacobsen
- Department of Endocrinology; Odense University Hospital; Odense Denmark
| | - O. N. Jensen
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense Denmark
| | - P. Bie
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
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Lankadeva YR, Singh RR, Tare M, Moritz KM, Denton KM. Loss of a kidney during fetal life: long-term consequences and lessons learned. Am J Physiol Renal Physiol 2014; 306:F791-800. [PMID: 24500691 DOI: 10.1152/ajprenal.00666.2013] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Epidemiological studies reveal that children born with a solitary functioning kidney (SFK) have a greater predisposition to develop renal insufficiency and hypertension in early adulthood. A congenital SFK is present in patients with unilateral renal agenesis or unilateral multicystic kidney dysplasia, leading to both structural and functional adaptations in the remaining kidney, which act to mitigate the reductions in glomerular filtration rate and sodium excretion that would otherwise ensue. To understand the mechanisms underlying the early development of renal insufficiency in children born with a SFK, we established a model of fetal uninephrectomy (uni-x) in sheep, a species that similar to humans complete nephrogenesis before birth. This model results in a 30% reduction in nephron number rather than 50%, due to compensatory nephrogenesis in the remaining kidney. Similar to children with a congenital SFK, uni-x sheep demonstrate a progressive increase in arterial pressure and a loss of renal function with aging. This review summarizes the compensatory changes in renal hemodynamics and tubular sodium handling that drive impairments in renal function and highlights the existence of sex differences in the functional adaptations following the loss of a kidney during fetal life.
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Krug AW, Tille E, Sun B, Pojoga L, Williams J, Chamarthi B, Lichtman AH, Hopkins PN, Adler GK, Williams GH. Lysine-specific demethylase-1 modifies the age effect on blood pressure sensitivity to dietary salt intake. AGE (DORDRECHT, NETHERLANDS) 2013; 35:1809-20. [PMID: 23054827 PMCID: PMC3776098 DOI: 10.1007/s11357-012-9480-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/17/2012] [Indexed: 05/08/2023]
Abstract
How interactions of an individual's genetic background and environmental factors, such as dietary salt intake, result in age-associated blood pressure elevation is largely unknown. Lysine-specific demethylase-1 (LSD1) is a histone demethylase that mediates epigenetic regulation and modification of gene transcription. We have shown previously that hypertensive African-American minor allele carriers of the LSD1 single nucleotide polymorphism (rs587168) display blood pressure salt sensitivity. Our goal was to further examine the effects of LSD1 genotype variants on interactions between dietary salt intake, age, and blood pressure. We found that LSD1 single nucleotide polymorphism (rs7548692) predisposes to increasing salt sensitivity during aging in normotensive Caucasian subjects. Using a LSD1 heterozygous knockout mouse model, we compared blood pressure values on low (0.02 % Na(+)) vs. high (1.6 % Na(+)) salt intake. Our results demonstrate significantly increased blood pressure salt sensitivity in LSD1-deficient compared to wild-type animals with age, confirming our findings of salt sensitivity in humans. Elevated blood pressure in LSD1(+/-) mice is associated with total plasma volume expansion and altered renal Na(+) excretion. In summary, our human and animal studies demonstrate that LSD1 is a genetic factor that interacts with dietary salt intake modifying age-associated blood pressure increases and salt sensitivity through alteration of renal Na(+) handling.
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Affiliation(s)
- Alexander W Krug
- Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115, USA,
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Lankadeva YR, Singh RR, Hilliard LM, Moritz KM, Denton KM. Blunted sodium excretion in response to a saline load in 5 year old female sheep following fetal uninephrectomy. PLoS One 2012; 7:e47528. [PMID: 23077628 PMCID: PMC3471853 DOI: 10.1371/journal.pone.0047528] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 09/12/2012] [Indexed: 01/14/2023] Open
Abstract
Previously, we have shown that fetal uninephrectomy (uni-x) causes hypertension in female sheep by 2 years of age. Whilst the hypertension was not exacerbated by 5 years of age, these uni-x sheep had greater reductions in renal blood flow (RBF). To further explore these early indications of a decline in renal function, we investigated the renal response to a saline load (25 ml/kg/40 min) in 5-year old female uni-x and sham sheep. Basal mean arterial pressure was ∼15 mmHg greater (P(Group)<0.001), and sodium excretion (∼50%), glomerular filtration rate (∼30%, GFR) and RBF (∼40%) were all significantly lower (P(Group)<0.01) in uni-x compared to sham animals. In response to saline loading, sodium excretion increased significantly in both groups (P(Time)<0.001), however this response was blunted in uni-x sheep (P(GroupxTime)<0.01). This was accompanied with an attenuated increase in GFR and fractional sodium excretion (both P(GroupxTime)<0.05), and reduced activation of the renin-angiotensin system (both P<0.05), as compared to the sham group. The reduction in sodium excretion was associated with up-regulations in the renal gene expression of NHE3 and Na(+)/K(+) ATPase α and β subunits in the kidney cortex of the uni-x compared to the sham animals (P<0.05). Notably, neither group completely excreted the saline load within the recovery period, but the uni-x retained a higher percentage of the total volume (uni-x: 48±7%; sham: 22±9%, P<0.05). In conclusion, a reduced ability to efficiently regulate extracellular fluid homeostasis is evident in female sheep at 5 years of age, which was exacerbated in animals born with a congenital nephron deficit. Whilst there was no overt exacerbation of hypertension and renal insufficiency with age in the uni-x sheep, these animals may be more vulnerable to secondary renal insults.
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Affiliation(s)
| | - Reetu R. Singh
- Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | | | - Karen M. Moritz
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | - Kate M. Denton
- Department of Physiology, Monash University, Victoria, Australia
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Abstract
Nonmodulation is a process in which there is a disorder in angiotensin-dependent control of the renal circulation and adrenal aldosterone release. The abnormalities are associated with an inability to handle a sodium load and salt-sensitive hypertension. All of the features are corrected by angiotensin-converting enzyme inhibition. A striking family history of hypertension and concordance of responses to angiotensin II in sibling pairs have suggested a familial factor. Genes governing renin substrate (angiotensinogen) production showed gene polymorphisms in nonmodulators. As nonmodulation occurs in approximately 40% of patients with essential hypertension, clearly other genes must contribute.
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Giacché M, Vuagnat A, Hunt SC, Hopkins PN, Fisher ND, Azizi M, Corvol P, Williams GH, Jeunemaitre X. Aldosterone stimulation by angiotensin II : influence of gender, plasma renin, and familial resemblance. Hypertension 2000; 35:710-6. [PMID: 10720583 DOI: 10.1161/01.hyp.35.3.710] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aldosterone response to infused angiotensin II (Ang II) in patients receiving a low-salt diet has been described as an important phenotype for genetic studies on human hypertension. The objectives of the present study were to determine the parameters that influence this intermediate phenotype as a quantitative trait and to assess the importance of its familial resemblance in hypertensive sibling pairs. Two hundred one white hypertensive subjects (95 families: 84 pairs and 11 trios) were selected in 3 centers. The patients followed the same protocol, which included a 4-week withdrawal period of antihypertensive therapy, a 1-week period on a low-salt diet, and a 30-minute infusion of Ang II. The increase in the aldosterone level was greater in women than in men (29.1+/-16.2 versus 18.2+/-9.6 ng/dL, P<0.0001). A strong relationship was found with age (r=-0.54, P<10(-4)) and plasma renin activity (r=0.32, P<10(-4)) in women but not in men. Weak correlations of the aldosterone response to Ang II were observed for the whole set of sibling pairs (r=0.11, NS). Conversely, strong sibling correlations were found among brother-brother pairs (r=0.40, n=36) and among sister-sister pairs as soon as age or menopausal status was considered. Similar results were obtained when the Ang I-aldosterone response was analyzed as a qualitative trait (kappa=0. 35, P<0.008 in brother-brother pairs). We conclude that age, gender, and plasma renin are strong determinants of the aldosterone response to Ang II, with strong sibling correlations in men and postmenopausal women. These relationships will have to be considered in future linkage and association studies.
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Affiliation(s)
- M Giacché
- Department of Hypertension, Centre d'Investigation Clinique 9201 AP-HP/INSERM, Hôpital Broussais, and INSERM U36, College de France, Paris, France
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Maybaum N, Gorodetsky E, Kalman R, Weinstock M. Role of renal nerves in hemodynamic and natriuretic responses to saline in rabbits with impaired baroreflex sensitivity. Ren Fail 1998; 20:219-28. [PMID: 9574446 DOI: 10.3109/08860229809045105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The hemodynamic and urinary Na+ excretory response to a 2.5-fold increase in NaCl by i.v. infusion were assessed in conscious male rabbits with either high (BShi, salt-insensitive) or low (BSlo, salt-sensitive) cardiac baroreflex sensitivity, before, and 11-14 days after bilateral renal denervation. Effective renal plasma flow (ERPF) and proximal tubular Na+ reabsorption were measured by para-amino-hippurate (PAH) and Li+ clearances, respectively, before and after NaCl infused for 2 hr at a rate of 0.11 mL/kg/min. Intact BShi rabbits, showed a significant natriuresis within 30 min which was associated with an increase in ERPF and inhibition of proximal tubular reabsorption. The Na+ excretion rate was much slower in BSlo rabbits, while ERPF and proximal tubular reabsorption remained unchanged. Renal denervation reduced MAP, increased basal ERPF, Na+ and Li+ excretion in both groups, and abolished the difference in the renal hemodynamic re-sponse and Li+ excretion to increased NaCl, but not that in the rate of Na+ excretion. The data suggest that BSlo rabbits do not increase their ERPF and Li+ in response to saline because of an inability to bring about an inhibition of renal sympathetic nerve activity. This could be due to an impairment in the sensitivity of their cardiopulmonary baroreceptors. The difference in the rate of natriuresis in the two groups of rabbits which remained after renal denervation could involve an additional hormonal or a local renal mechanism.
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Affiliation(s)
- N Maybaum
- Department of Pharmacology, Hebrew University Hadassah Medical Centre, Ein Kerem, Jerusalem, Israel
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Pidgeon GB, Richards AM, Nicholls MG, Lewis LK, Yandle TG, Rademaker MT, Charles CJ, Bailey RR, Lynn KL. Comparison of the effects of ouabain and brain natriuretic peptide in saline-loaded sheep. Clin Exp Pharmacol Physiol 1997; 24:807-13. [PMID: 9363361 DOI: 10.1111/j.1440-1681.1997.tb02695.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
1. It has been claimed that ouabain is an endogenous hormone that may be pivotal in the pathogenesis of some forms of hypertension and may exaggerate natriuresis in situations characterized by volume overload. We compared the haemodynamic, renal and endocrine effects of ouabain (at approximately 187 ng/kg per min for 2 h) with those of brain natriuretic peptide (BNP; at 5 pmol/kg per min for 2 h) in nine saline-loaded sheep in a balanced, randomized, single-blind, placebo-controlled crossover study. 2. Brain natriuretic peptide infusion reduced mean arterial pressure whereas ouabain infusion caused no change. Haematocrit rose steadily during BNP infusion but fell during ouabain infusion. Neither ouabain nor BNP affected urine volume, sodium, potassium or creatinine excretion. Mean heart rate declined during the ouabain and placebo infusions, but was not altered during BNP infusion. Endogenous ouabain concentrations were not detectable at baseline or during BNP or placebo infusions, but rose to concentrations of 11 +/- 1.3 nmol/L during the ouabain infusion. 3. These results suggest that ouabain is not an endogenous hormone present at physiologically relevant concentrations. Furthermore, ouabain does not cause natriuresis during saline-loading in sheep and is therefore unlikely to be responsible for the exaggerated natriuresis seen in some forms of hypertension.
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Affiliation(s)
- G B Pidgeon
- Department of Nephrology, Christchurch Hospital, New Zealand
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14
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Turner ST, Kardia SL. Relationship between renal plasma flow response to angiotensin II and blood pressure in a population-based sample. J Hypertens 1997; 15:495-502. [PMID: 9170001 DOI: 10.1097/00004872-199715050-00004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To assess whether interindividual variation in renal plasma flow or in its response to angiotensin II infusion is associated with interindividual differences in blood pressure in a population-based sample of 287 non-Hispanic whites (143 women and 144 men), aged 20-49.9 years. METHODS After seven days of eating a high-sodium diet (260 mmol/day), the renal plasma flow was determined by measuring the clearance of p-aminohippurate before and after infusion of 3 ng/kg per min angiotensin II. Multiple linear regression methods were used to assess whether measures of the renal plasma flow and of its response to angiotensin II infusion were predictive of systolic or diastolic blood pressures measured prior to administration of the high-sodium diet, on day 6 of the high-sodium diet, or during the renal clearance procedure on day 7 prior to angiotensin II infusion. RESULTS There was some evidence that measures of the renal plasma flow and of its response to angiotensin II infusion during the high-sodium diet were statistically significant predictors of measures of blood pressure in women; there was less evidence for this for blood pressures in men. Interindividual variation in measures of the renal plasma flow and of its response to angiotensin II infusion explained less than 10% of the interindividual variation in any measure of the blood pressure in both sexes. CONCLUSION These results suggest that interindividual variation in renal plasma flow ad in its response to angiotensin II infusion during a high-sodium diet will be of limited utility in elucidating the basis for interindividual differences in blood pressure.
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Affiliation(s)
- S T Turner
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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15
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Borghi C, Boschi S, Costa FV, Bacchelli S, Degli Esposti D, Immordino V, Piccoli M, Ambrosioni F. Low dose of ACE-inhibitor enhances sodium excretion in volume expanded patients with borderline hypertension. Blood Press 1996; 5:105-12. [PMID: 8860099 DOI: 10.3109/08037059609062116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The purpose of the present study was to separately investigate the effects of two different dosages of captopril on pressor, vascular and humoral response to acute extracellular volume expansion in patients with borderline hypertension (BHT). Thirty-five patients were randomly allocated in two groups undergoing acute saline infusion (0.40 ml/min/kg for 45 min and 0.15 ml/min/kg for 75 min)before and after a 7-day period of treatment with either placebo or captopril at the dose of 12.5 (LD-CAP) or 50 mg (HD-CAP) twice a day. At baseline the effects of LD-CAP were limited to an increase in PRA and to a decrease in plasma aldosterone whereas HD-CAP decreased systolic and diastolic blood pressure (SBP, DBP), forearm vascular resistance (FVR) and increased venous distensibility (VV(30)) as well. After saline loading patients treated with HD-CAP showed an increase in SBP, DBP not observed in patients allocated to LD-CAP. Urinary sodium excretion in response to NaCl loading was selectively enhanced by LD-CAP (+25%) whereas HD-CAP did not (+6.3%). The present data suggest that low-doses of ACE-inhibitors acting through a selective blockade of RAA not associated with hemodynamic changes can enhance the natriuretic response to acute volume expansion in borderline hypertensives.
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Affiliation(s)
- C Borghi
- Third Department of Internal Medicine, Department of Clinical Pharmacology and Therapeutics, University of Bologna, Italy
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16
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Williams GH. Genetic approaches to understanding the pathophysiology of complex human traits. Kidney Int 1994; 46:1550-3. [PMID: 7700003 DOI: 10.1038/ki.1994.443] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Genetic approaches to understanding the pathophysiology of complex human traits, for example, hypertension, can complement physiologic analyses and are likely to improve our ability to treat or prevent the disease. A particularly useful approach is to perform linkage analysis with candidate genes using intermediate phenotypes. This has proven successful so far in identifying two genes involved in hypertension. The first was a fusion gene mutation which linked the regulatory region of the 11B-hydroxylase gene to the coding sequence for the protein of aldosterone synthetase. This mutant gene is responsible for the condition glucocorticoid-remediable aldosteronism (GRA). The intermediate phenotype used was increased levels of the adrenal steroids 18-oxo and hydroxycortisol. The gene for GRA was identified using a pedigree approach. It is likely, to identify other genes in hypertension, that the most appropriate population to be affected would be sib pairs, that is, sibling pairs who both have hypertension. In a recent study the angiotensinogen gene also was linked to hypertension in individuals who had severe or early onset hypertension. In addition, a variant of the angiotensinogen gene, substitution of threonine rather than methionine at codon 235, was specifically associated with hypertension. In a separate study, the T235 homozygote of the angiotensinogen gene was associated with the non-modulating intermediate phenotype of essential hypertension. Since converting enzyme inhibitors appear to correct the specific defect underlying the elevated blood pressure in non-modulators, identification of the gene potentially associated with non-modulation raises the strong possibility that genetic screening will allow for more specific therapy.
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Affiliation(s)
- G H Williams
- Brigham and Women's Hospital, Boston, Massachusetts
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17
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Ferri C, Bellini C, Coassin S, Baldoncini R, Luparini RL, Perrone A, Santucci A. Abnormal atrial natriuretic peptide and renal responses to saline infusion in nonmodulating essential hypertensive patients. Circulation 1994; 90:2859-69. [PMID: 7994831 DOI: 10.1161/01.cir.90.6.2859] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Nonmodulation seems to represent an inheritable trait characterized by abnormal angiotensin-mediated control of aldosterone release and renal blood supply and salt-sensitive hypertension. Recently, we demonstrated that atrial natriuretic peptide (ANP) response to angiotensin II also is altered in nonmodulators. Moreover, an abnormal ANP response to acute volume expansion has been shown by others in hypertensive patients displaying some features of nonmodulators. These data induced us to hypothesize that nonmodulators. These data induced us to hypothesize that nonmodulation could be characterized by an abnormal ANP response to saline load. METHODS AND RESULTS Forty-three essential hypertensive men were subdivided into low-renin patients (n = 12), nonmodulators (n = 15), and modulators (n = 16) according to their renin profile and ability to modulate aldosterone and p-aminohippurate clearance responses to a graded angiotensin II infusion (1.0 ng.kg-1.min-1 and 3.0 ng.kg-1.min-1 for 30 minutes each) on both a low- (10 mmol Na+ per day) and a high- (210 mmol Na+ per day) Na+ intake. The intravenous saline load (0.25 mL.kg-1.min-1 for 2 hours) performed on a low-Na+ diet increased plasma ANP levels in low-renin (from 14.30 +/- 4.68 to 23.30 +/- 7.52 fmol/mL at 120 minutes, P < .05) and modulating patients (from 10.95 +/- 3.55 to 18.21 +/- 5.42 fmol/mL at 120 minutes, P < .05), whereas it did not change the hormone levels in nonmodulators (from 10.77 +/- 3.25 to 13.83 +/- 5.70 fmol/mL at 120 minutes, P = NS). When patients switched from a low- to a high-NaCl diet, plasma ANP levels increased significantly in all groups. However, when the saline load was repeated on a high-NaCl intake, ANP levels increased in both low-renin and modulating patients (P < .05), whereas it failed to increase in nonmodulators. CONCLUSIONS Nonmodulating hypertensive patients showed a reduced ANP response to saline infusion in the presence of a normal increase of plasma ANP with dietary NaCl load. The impaired ANP response to saline infusion could be due to a different distribution of volume load and contribute to determining the reduced ability to excrete sodium that is commonly described in nonmodulators.
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Affiliation(s)
- C Ferri
- Institute of I Clinica Medica, Andrea Cesalpino Foundation, University of Rome La Sapienza, Italy
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18
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Luparini RL, Ferri C, Santucci A, Balsano F. Atrial natriuretic peptide in non-modulating essential hypertension. Hypertension 1993; 21:803-9. [PMID: 8500861 DOI: 10.1161/01.hyp.21.6.803] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To evaluate the atrial natriuretic peptide response to angiotensin II (Ang II) infusion in non-modulating hypertension, we studied 31 men with essential hypertension. These patients were subdivided into groups of low renin patients (n = 8), non-modulators (n = 11), and modulators (n = 12) according to their renin profile and ability to modulate renin and aldosterone responses to a graded infusion of Ang II (1.0 and 3.0 ng/kg per minute) on a low Na+ intake (10 mmol Na+ per day). During basal conditions, plasma atrial natriuretic peptide was higher (p < 0.05) in low renin patients (16.34 +/- 2.67 fmol/mL) than in both modulators (10.59 +/- 4.29 fmol/mL) and non-modulators (9.85 +/- 2.64 fmol/mL). During Ang II infusion, plasma atrial natriuretic peptide significantly increased in both low renin (27.67 +/- 2.61 fmol/mL at 60 minutes, p < 0.01) and modulating (20.36 +/- 3.07 fmol/mL at 60 minutes, p < 0.05) patients, whereas it did not change in non-modulators (13.94 +/- 4.39 fmol/mL, NS). After 5 days on a high sodium intake (200 mmol Na+ per day), plasma atrial natriuretic peptide rose in modulating (20.61 +/- 2.31 fmol/mL, p < 0.01 versus low sodium intake), non-modulating (20.11 +/- 6.48 fmol/mL, p < 0.01 versus low sodium intake), and low renin (26.13 +/- 3.81 fmol/mL, p < 0.001 versus low sodium intake) hypertensive patients. When the Ang II infusion was repeated with a high sodium intake, plasma atrial natriuretic peptide increased again in low renin and modulating patients, whereas it did not change in non-modulators.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R L Luparini
- Institute of I Clinica Medica, Andrea Cesalpino Foundation, University La Sapienza, Rome, Italy
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19
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Williams GH, Dluhy RG, Lifton RP, Moore TJ, Gleason R, Williams R, Hunt SC, Hopkins PN, Hollenberg NK. Non-modulation as an intermediate phenotype in essential hypertension. Hypertension 1992; 20:788-96. [PMID: 1452294 DOI: 10.1161/01.hyp.20.6.788] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Non-modulation is a trait characterized by abnormal angiotensin-mediated control of aldosterone release and the renal blood supply. To determine whether non-modulation defines a specific subgroup of the hypertensive population and its utility as an intermediate phenotype, we have studied the distribution of this quantitative trait, whether its features are reproducible on repeated testing, and whether there is concordance of its multiple features. Essential hypertensive patients (224) and normotensive subjects (119) received an infusion of angiotensin II (Ang II) at 3 ng.kg-1.min-1 for 30-45 minutes. p-Aminohippurate (PAH) clearance was assessed as an index of renal plasma flow while the subjects were on a 200 meq sodium diet; plasma aldosterone levels were measured while the subjects were on a 10 meq sodium diet. In 54 subjects, diuretic-induced volume depletion superimposed on a low salt diet was substituted for the Ang II infusion. The results of each study were submitted to maximum likelihood analysis to assess bimodality. In response to both diuretic-induced volume depletion (p < 0.000023) and Ang II infusion (p < 0.0009), aldosterone responses were bimodally distributed in the essential hypertensive but not in the normotensive subjects, suggesting that this trait identifies a discrete subgroup. In the 59 subjects who had both an adrenal and renal study, 50 (85%) were concordant. Finally, in 27 subjects studied two to six times over a span of 1-60 months, the intraclass correlations of the adrenal, PAH, or both responses were highly significant (p values between 0.001 and 0.00007), indicating high reproducibility of results on repeated testing.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G H Williams
- Endocrine-Hypertension Division, Brigham and Women's Hospital, Boston, MA 02115
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20
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Kjeldsen SE, Gupta RK, Krause L, Weder AB, Julius S. Does blood pressure reduction necessarily compromise cardiac function or renal hemodynamics? Effects of the angiotensin-converting enzyme inhibitor quinapril. Am Heart J 1992; 123:1433-8. [PMID: 1575171 DOI: 10.1016/0002-8703(92)91066-a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Clinical studies indicate that the angiotensin-converting enzyme inhibitor quinapril is an effective antihypertensive agent when administered once daily. At the end of a 4-week, double-blind crossover trial comparing quinapril and placebo, patients were admitted for a hemodynamic profile study 12 hours after taking the previous dose. A final 20 mg dose of quinapril had no additional effect on blood pressure. This is interesting inasmuch as the plasma half-life of the active metabolite quinaprilat is approximately 2 hours and the effective accumulation half-life is approximately 3 hours. The blood pressure reduction in patients with mild hypertension receiving long-term quinapril therapy may be more closely related to prolonged angiotensin-converting enzyme inhibition or to an effect on tissue angiotensin II concentration than to the plasma half-life. This may be the case particularly for cardiac output and renal circulation, because quinapril lowers total vascular resistance without increasing cardiac output or disturbing autoregulation of renal blood flow. Reduced ventricular wall stress, improved diastolic function, and lower renal perfusion pressure may spare cardiac function and glomeruli from hypertensive vascular damage.
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Affiliation(s)
- S E Kjeldsen
- Department of Internal Medicine, Ullevaal University Hospital, Oslo, Norway
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21
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Harshfield GA, Alpert BS, Pulliam DA, Willey ES, Somes GW, Stapelton FB. Sodium excretion and racial differences in ambulatory blood pressure patterns. Hypertension 1991; 18:813-8. [PMID: 1743762 DOI: 10.1161/01.hyp.18.6.813] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The influence of Na+ excretion and race on casual blood pressure and ambulatory blood pressure patterns was examined in a biracial sample of healthy, normotensive children and adolescents (10-18 years; n = 140). The slopes relating 24-hour urinary Na+ excretion to systolic blood pressure were different for both black and white subjects for casual blood pressure (p less than 0.001) and blood pressure during sleep (p less than 0.03). For casual blood pressure, the slope was significant for black subjects (beta = 0.17; p less than 0.001) but not for white subjects. For blood pressure during sleep, the slope was again significant for black subjects (beta = 0.08; p less than 0.01) but not for white subjects. Na+ excretion was also related to awake levels of systolic blood pressure for black subjects (beta = 0.08, r = 0.36; p less than 0.01), although the slopes for both black and white subjects were not significantly different. Further analyses indicated the results were not due to racial differences in 24-hour urinary K+ excretion. However, plasma renin activity was marginally related to Na+ excretion in white subjects (r = 0.22; p less than 0.06) but not black subjects, a finding that is consistent with previous studies. Na+ excretion was not associated with diastolic blood pressure or heart rate in either group under any condition. The results of this study support research that has demonstrated a stronger relation between Na+ handling and casual blood pressure in black subjects and extend these findings to blood pressure while the subject is both awake and asleep.
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Affiliation(s)
- G A Harshfield
- Department of Pediatrics, University of Tennessee, Memphis 38103
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22
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Osborn EC, Fearn LM, Francis RJ, MacKenzie JC, Wilson J. Receptors for angiotensins I and II: their relevance to renal haemodynamics, blood pressure control and hind-limb blood flow. Med Hypotheses 1991; 36:6-16. [PMID: 1766416 DOI: 10.1016/0306-9877(91)90157-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The well established differential pulmonary handling of angiotensins I and II indicates the possibility that vascular receptors for the deca- and octa-peptides do not necessarily involve common sites in the renal vasculature either. Experimental findings involving haemodynamic changes within the kidney in anaesthetised and conscious sheep, with utilization of the angiotensins, and also of noradrenaline, are briefly presented; the implications of the intra-renal water and creatinine transfers are discussed, especially as they concern the possible location of angiotensin receptors in the renal blood vessels. Other aspects of the relationships between the peptides are also taken into account particularly with regard to a postulated angiotensin I [NaCl] dependent peritubular capillary antidiuretic action, angiotensin converting enzyme inhibition, Goldblatt clamp induced hypertension and blood flow through the hind-limbs.
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Affiliation(s)
- E C Osborn
- Department of Renal Medicine, Southmead Hospital, Bristol, UK
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23
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Nosadini R, Semplicini A, Fioretto P, Lusiani L, Trevisan R, Donadon V, Zanette G, Nicolosi GL, Dall'Aglio V, Zanuttini D. Sodium-lithium countertransport and cardiorenal abnormalities in essential hypertension. Hypertension 1991; 18:191-8. [PMID: 1885227 DOI: 10.1161/01.hyp.18.2.191] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The rate of red blood cell sodium-lithium countertransport is elevated only in a subgroup of patients with essential hypertension. We have therefore compared renal and cardiac function and morphology in two groups of hypertensive patients with high (n = 23) or normal (n = 22) sodium-lithium countertransport (mean +/- SEM: 0.61 +/- 0.10 versus 0.29 +/- 0.07 mmol/l red blood cells.hr). The two groups were similar in age, sex distribution, body mass index, smoking habit, duration of hypertension, and actual levels of untreated blood pressure. Hypertensive patients with elevated sodium-lithium countertransport activity showed elevated glomerular filtration rate (118 +/- 2 versus 109 +/- 2 ml/min.1.73 m2; p less than 0.001), albumin excretion rate (23 +/- 3 versus 14 +/- 2 micrograms/min; p less than 0.001), larger kidney volume (250 +/- 15 versus 203 +/- 13 ml.1.73 m2; p less than 0.01), lower lithium clearance rate (26.7 +/- 0.3 versus 28.9 +/- 0.3 ml/min.1.73 m2; p less than 0.01), and higher total body exchangeable sodium (2,716 +/- 33 versus 2,485 +/- 41 mmol.1.73 m2; p less than 0.01). Left ventricular mass index (139 +/- 6 versus 119 +/- 6 g/m2; p less than 0.05), relative wall thickness (0.39 +/- 0.05 versus 0.29 +/- 0.04 cm; p less than 0.001), and left posterior wall plus intraventricular septum thickness (2.02 +/- 0.04 versus 1.76 +/- 0.03 cm; p less than 0.05) were also higher in patients with high sodium-lithium countertransport. Hypertensive patients with normal sodium-lithium countertransport had renal and cardiac parameters similar to those of a normotensive control group (n = 21) except for a higher glomerular filtration rate and left ventricular mass index.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Nosadini
- Department of Internal Medicine, Università di Padova, Italy
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24
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Abstract
Clinical studies requiring controlled electrolyte balance have traditionally been conducted in an inpatient (IP), metabolic ward setting. The purpose of this study was to test the feasibility of performing such studies in an outpatient (OP) clinical research setting. Focusing on sodium (Na) and potassium (K) balance, we retrospectively compared 28 subjects studied as OP vs 25 studied as IP on our metabolic ward. We assessed their adherence to our metabolic diets and their compliance with serial 24-hr urine collections. Dietary compliance was assessed by checksheet and urinary Na excretion; urine collection accuracy was determined by serial 24-hr creatinine excretion. The diets for both studies contained a low Na phase (10 mEq) and a high Na phase (200 mEq for IP and 250 mEq for OP), each lasting 1 week. When in balance on the low Na diet, 24-hr Na excretion was 4.6 +/- 0.7 mEq for OP and 13.4 +/- 2.2 mEq for IP, indicating excellent compliance with the low salt diet. Na excretion on the high Na diet was 184.5 +/- 7.4 mEq for OP and 195.3 +/- 9.6 mEq for IP. These values were not significantly different from each other; however, the OP were significantly less than their diet of 250 mEq Na (p less than 0.05). This difference may have been due to dermal Na losses. K excretion was also similar in the two groups. There was no significant difference in the reproducibility of individual multiple urinary creatinine measurements in OP vs IP.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M L McCullough
- Endocrine-Hypertension Division, Brigham and Women's Hospital, Boston, Massachusetts 02115
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25
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Williams GH, Hollenberg NK. Non-modulating hypertension. A subset of sodium-sensitive hypertension. Hypertension 1991; 17:I81-5. [PMID: 1987016 DOI: 10.1161/01.hyp.17.1_suppl.i81] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- G H Williams
- Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, Mass
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26
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Hollenberg NK, Williams GH. The Renin Angiotensin System, the Kidney, and the Pathogenesis of Hypertension. Nephrology (Carlton) 1991. [DOI: 10.1007/978-3-662-35158-1_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Abstract
Hypertension is a clinical disease with a prevalence sufficiently high in acculturated societies to warrant it being designated a serious public health problem. In population studies, blood pressure has been found to be a continuously distributed risk variable with mortality directly related to the level of blood pressure. Thus, hypertension is both a disease and a risk factor. Classic genetic studies suggest that the predisposition for the development of hypertension is an inherited trait that becomes manifest when coupled with one or more environmental insults. Risk factors for hypertension include age, weight, sedentary lifestyle, excessive dietary sodium intake, and excessive alcohol intake. Current and future research is being directed toward the identification of predictors of hypertension that can be conceptualized according to demographic, clinical, genetic, challenge-response, and laboratory predictors. The intent is to identify subjects with a high probability for the development of hypertension in advance of the rise in blood pressure so that appropriate interventions can be implemented as early as possible.
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Affiliation(s)
- M J Horan
- Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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28
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Falkner B, Kushner H. Effect of chronic sodium loading on cardiovascular response in young blacks and whites. Hypertension 1990; 15:36-43. [PMID: 2295513 DOI: 10.1161/01.hyp.15.1.36] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effect of long-term oral sodium loading on blood pressure and on stress-induced cardiovascular response was studied in normotensive and marginally hypertensive young adults. The 121 subjects, 18-23 years old, included 38 whites and 83 blacks. Blood pressure and heart rate response to the stress of mental arithmetic was measured before and after 14 days of sodium load, which consisted of 10 g NaCl/day added to the usual diet. A sodium-sensitive response to sodium load occurred in 18.4% of whites and 37.3% of blacks. Sodium-insensitive subjects had a higher rate of sodium excretion (p less than 0.001). Sodium-sensitive hypertensive subjects had a significantly greater weight gain (p less than 0.001). A significant correlation between blood pressure change and sodium excretion (r = -0.28, p less than 0.01) occurred in the sodium-sensitive group. The high sodium intake did not augment the blood pressure or heart rate response to the beta-adrenergic-mediated stimulus of mental arithmetic in the population when grouped by blood pressure, race, or sodium sensitivity. These results suggest that blood pressure increase in response to sodium load, particularly in blacks, is related to functional changes in peripheral vascular resistance.
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Affiliation(s)
- B Falkner
- Department of Pediatrics, Hahnemann University, Philadelphia, Pennsylvania 19102
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29
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Abstract
The possible contribution of dietary electrolyte intake as a cause of or contributor to the development of hypertension has been intensively investigated for over 50 years. Evidence from various sources suggests a role for sodium-salt, chloride, calcium, and magnesium. In this article, we will review the evidence supporting a role for each of these electrolytes in human hypertension.
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Affiliation(s)
- T J Moore
- Endocrine-Hypertension Division, Brigham and Women's Hospital, Boston, Massachusetts 02115
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30
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Williams GH, Hollenberg NK. Sodium-sensitive essential hypertension: emerging insights into an old entity. J Am Coll Nutr 1989; 8:490-4. [PMID: 2695548 DOI: 10.1080/07315724.1989.10720318] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Essential hypertension has long been assumed to be a multifactorial disease. However, recent evidence suggests that it is a syndrome rather than a disease with a common symptom--an elevated blood pressure. One large segment of the hypertensive population--approximately 60%--has in common an increased blood pressure sensitivity to salt intake. Further analysis of this subgroup suggests that it is also heterogeneous, consisting of at least six major entities: renal parenchymal disease, bilateral renal artery stenosis, primary aldosteronism, acromegaly, low renin essential hypertension, and the most recently described entity--nonmodulating essential hypertension. This subset's name is derived from the fact that sodium intake does not modify (modulate) renovascular and adrenal responses to angiotensin II, as occurs in normotensives and modulating hypertensive patients. The following abnormalities have been reported in these patients: (1) a failure of renal blood flow to increase with salt loading; (2) a reduced ability to excrete a salt load; (3) reduced renin suppression both by salt and angiotensin II; and (4) a hypertensive response to salt load. These patients also have a strong family history for hypertension and an increase in erythrocyte sodium countertransport. With a better understanding of the mechanisms underlying the elevated blood pressure in a specific patient, a more rational approach to therapy is possible. For example, in the salt-sensitive hypertensive patient a diuretic would be the presumed treatment of choice. While this is correct for some salt-sensitive hypertensives, in nonmodulators diuretics may be relative ineffective while converting enzyme inhibitors may be more effective because they specifically correct the underlying pathophysiologic derangement.
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Affiliation(s)
- G H Williams
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
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31
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Abstract
Because the kidney is both the source of circulating renin and the final determinant of the state of sodium balance, which in turn defines responsiveness to angiotensin II, one might have anticipated substantial interest in the impact of converting enzyme inhibitors on the kidney when these agents were developed. The lessons learned about the role of the renin-angiotensin system in normal renal perfusion and function, and possible disorders of control that contribute to disease in patients with essential hypertension, renovascular hypertension, and chronic progressive renal parenchymal disease are reviewed. In each case, the lessons here have important implications for the clinical application of converting enzyme inhibition.
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Affiliation(s)
- N K Hollenberg
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115
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Finn WL, Gordon RD, Tunny TJ, Klemm SA, Hamlet SM. Effects of volume expansion and contraction on plasma levels of atrial natriuretic peptide in man. Clin Exp Pharmacol Physiol 1988; 15:311-5. [PMID: 2978743 DOI: 10.1111/j.1440-1681.1988.tb01079.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
1. Effects of saline infusion and blood removal on atrial natriuretic peptide (ANP) in normal subjects were examined in order to better define the magnitude of acute central volume regulatory influences on ANP. 2. Plasma ANP levels increased progressively during volume expansion with saline infusion, increasing by 18% after 30 min and by 93% after 120 min, and did not change during recumbency alone. 3. Plasma ANP levels immediately after a standard blood donation performed semirecumbent were significantly lower than before blood donation; they fell by 18%. 4. The magnitude of the fall in ANP induced by blood donation correlated significantly with basal plasma ANP. 5. In man, ANP responds to both increases and decreases in central blood volume, consistent with a role for ANP in blood volume homeostasis.
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Affiliation(s)
- W L Finn
- University of Queensland Department of Medicine, Greenslopes Hospital, Brisbane, Queensland, Australia
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Gill JR, Güllner G, Lake CR, Lakatua DJ, Lan G. Plasma and urinary catecholamines in salt-sensitive idiopathic hypertension. Hypertension 1988; 11:312-9. [PMID: 3281896 DOI: 10.1161/01.hyp.11.4.312] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Nineteen patients with normal renin idiopathic hypertension were arbitrarily classified as salt-sensitive or salt-resistant depending on whether their mean arterial pressure did or did not increase by 8% or more when sodium intake was increased. The responses of the two subsets and of five normal subjects to sodium intakes of 9, 109, and 249 mEq/day given for 7 days were as follows: The salt-sensitive subjects retained more sodium than normal and plasma or urinary norepinephrine did not decrease when they were given a high sodium intake; urinary dopamine was normal but did not increase normally when sodium intake was increased. The salt-resistant subjects excreted sodium normally and plasma and urinary norepinephrine was decreased by 30 and 37%, respectively, when they were given a high sodium intake; urinary dopamine was supernormal and did not increase further when sodium intake was increased. Cumulative sodium retention during the high sodium intake was directly related to the percentage of change in plasma norepinephrine in the hypertensive subjects, suggesting that renal adrenergic activity was a factor in the impaired sodium excretion in the salt-sensitive patients. Cumulative sodium retention and the percentage of change in plasma norepinephrine were inversely related to urinary dopamine in the hypertensive subjects, suggesting that increased formation of dopamine in renal and neural tissue in the salt-resistant subjects may have been responsible for the differences between the subsets in renal and adrenergic responses to a high sodium intake.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J R Gill
- Hypertension-Endocrine Branch, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
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Abstract
The epidemiologic correlation of chronic dietary salt intake among populations with the prevalence of hypertension has resulted in the concept that sodium plays an etiologic role in the development of essential hypertension (EH). However, the association of sodium intake with blood pressure in individuals within populations has been difficult to demonstrate. The differing human responses to sodium intake are dependent upon the individual level of sodium sensitivity or sodium resistance. Factors associated with sodium sensitivity are race, age, and other dietary factors. More recent investigations have pursued the interaction of sodium intake with other physiologic parameters including neurogenic activity, vascular structure, renal function, and other cations such as potassium and calcium. The observations that some humans demonstrate very little increase in blood pressure despite high levels of sodium intake supports the concept that a high sodium intake alone is not a single causal factor in hypertension. Sodium intake appears to interact with renal excretory capacity and vascular compliance. These varying physiologic functions must be delineated to characterize sodium sensitivity.
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Affiliation(s)
- B Falkner
- Department of Pediatrics, Hahnemann University, Philadelphia, Pennsylvania 19102
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Rabinowe SL, Redgrave JE, Shoback DM, Podolsky S, Hollenberg NK, Williams GH. Renin suppression by saline is blunted in nonmodulating essential hypertension. Hypertension 1987; 10:404-8. [PMID: 3308701 DOI: 10.1161/01.hyp.10.4.404] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We have reported that 50% of subjects with normal renin essential hypertension have both delayed suppression of the renin-angiotensin-aldosterone axis following sodium infusion and a delayed rate of excretion of an acute salt load. In another study we have also described a subset of patients with essential hypertension (called nonmodulators) who have several abnormalities, including a pressor response to salt loading. To evaluate whether the abnormalities described in these different groups of patients actually occur in the same patient, we assessed the renin-angiotensin-aldosterone axis response to short-term saline loading in 38 hypertensive patients. Their ability to modulate was determined by their renal vascular response to infused angiotensin II on a high salt diet (200 mEq Na). In response to a 3-hour infusion of saline, 75 mEq/hr, the reduction in plasma renin activity at both 60 and 120 minutes was significantly greater (p less than 0.008) in patients with normal modulation than in the nonmodulators. Plasma aldosterone levels were also significantly lower (p less than 0.001) in those with intact modulation. Thus, nonmodulating essential hypertensive patients have abnormalities in several systems that influence sodium homeostasis, including altered adrenal and renal vascular response to angiotensin II, altered renal blood flow response to salt loading, and a delayed suppression of the renin-angiotensin-aldosterone system with short-term saline infusion.
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Affiliation(s)
- S L Rabinowe
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
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Abstract
Increased cell membrane permeability to sodium is proposed as the initial event leading to high blood pressure in susceptible subjects when sodium intake is increased. All cells, including circulating cells, would be affected, but a key role for endothelial cells in the pathophysiology of the diastolic blood pressure elevation is proposed. Involvement of capillary endothelium could increase capillary permeability to proteins, and thereby would contribute to the altered fluid distribution on the high sodium diet which has been observed. If movement of fluid into the interstitium raised interstitial fluid pressure, venous capacitance would fall and right atrial pressure would rise. Several mechanisms would cause vascular smooth muscle tone to increase. Altered fluid distribution correlates with the rise in diastolic blood pressure from reduced sodium to high sodium diet, but arteriolar constriction would reduce capillary flow so altered fluid distribution occurs first. Arteriolar constriction could serve as a negative feedback to the raised atrial filling pressure by reducing raised capillary flow, which would decrease both altered fluid distribution and interstitial fluid pressure rise. Consequently, diastolic blood pressure would be chronically raised in 'sodium sensitive' subjects taking increased amounts of sodium in the diet. The relationship of the findings to "essential" hypertension and to premorbid cardiovascular sequelae, and the key role of capillary endothelium in the development of "essential" hypertension is discussed.
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Guidi E, Hollenberg NK. Differential pressor and renal vascular reactivity to angiotensin II in spontaneously hypertensive and Wistar-Kyoto rats. Hypertension 1987; 9:591-7. [PMID: 3294592 DOI: 10.1161/01.hyp.9.6.591] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The suggestion has been made that the Okamoto strain of spontaneously hypertensive rats (SHR) shares some features with a subgroup of patients with essential hypertension, called nonmodulators. One feature of nonmodulators is a renal blood flow response to angiotensin II (ANG II) that is blunted on a high salt diet; the blunted renal vascular response is corrected by converting enzyme inhibition. Renal blood flow (electromagnetic flowmeter) and pressor responses to graded ANG II doses (5-300 ng) were assessed in 24 SHR and 24 Wistar-Kyoto rats (WKY) ingesting 1.6% Na. In comparison to WKY, blood pressure was higher in SHR (155 +/- 4 vs 106 +/- 2 mm Hg; p less than 0.001), renal blood flow was lower (6.9 +/- 0.5 vs 8.2 +/- 0.4 ml/min/g; p less than 0.05), and the pressor response to ANG II was enhanced, (p less than 0.0005) but the renal vascular response was blunted (p less than 0.005). Captopril (1-30 mg/kg) reduced blood pressure more in SHR than in WKY but increased renal blood flow similarly in both strains. The blunted renal vascular response to ANG II in SHR was reversed by captopril, but inhibition of converting enzyme in the kidney did not parallel systemic inhibition. Maximum blockade of converting enzyme in the kidney appears to require a larger captopril dose than is required for systemic inhibition. These results suggest that the renal blood supply in SHR also shares some of the characteristics of nonmodulators and that the action of captopril on the renal blood flow probably reflects reversal of inappropriate intrarenal ANG II formation.
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Blackshear JL, Garnic D, Williams GH, Harrington DP, Hollenberg NK. Exaggerated renal vasodilator response to calcium entry blockade in first-degree relatives of essential hypertensive subjects. Hypertension 1987; 9:384-9. [PMID: 2435657 DOI: 10.1161/01.hyp.9.4.384] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Because an inherited renal factor may contribute to essential hypertension in humans, the study of family members is attractive. To assess the determinants of renal vascular tone, graded doses of either diltiazem (10-1000 micrograms/min) or acetylcholine (1-100 micrograms/min) were infused into the renal artery in 52 normotensive subjects, 16 with and 36 without a family history of hypertension when they were in balance on either a 10-mEq or 200-mEq sodium intake. Renal blood flow was measured with 133Xe. Restricted sodium intake potentiated renal vascular responses to diltiazem (p less than 0.01), suggesting a role for angiotensin as a determinant. In four subjects with no family history of hypertension on a 200-mEq sodium intake, angiotensin II in subpressor doses (1 ng/kg/min i.v.) induced renal vasoconstriction and enhanced the renal vasodilator action of diltiazem (p less than 0.001). In subjects with a family history of hypertension, the renal vascular response to diltiazem was enhanced (p less than 0.01) despite similar values of plasma renin activity, angiotensin II concentration, and sodium excretion. Because responses to acetylcholine were modified neither by sodium intake nor by family history, specificity for diltiazem was suggested. The intriguing possibility is raised that the enhanced renal vascular response to diltiazem reflects an abnormality in the control of renal vascular tone in the offspring of essential hypertensive subjects.
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Hollenberg NK, Williams GH. The renal response to converting enzyme inhibition and the treatment of sodium-sensitive hypertension. CLINICAL AND EXPERIMENTAL HYPERTENSION. PART A, THEORY AND PRACTICE 1987; 9:531-41. [PMID: 3038417 DOI: 10.3109/10641968709164221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Multiple lines of evidence suggest that intrarenal angiotensin AII formation participates in the control of renal perfusion and function. Inappropriate activation of this intrarenal system may participate in the pathogenesis of hypertension in about 45 percent of patients with essential hypertension, a group that we call "non-modulators" (NM). In NM the renal vascular response to AII is blunted when the subjects are on a high-salt diet, but appropriate when they are on a low-salt diet. Converting enzyme inhibition in NM induces a larger increase in renal blood flow, than occurs in normal subjects or other patients with essential hypertension, most evident when they are on a high-salt diet. The renal vasodilatation is not due to prostaglandin or bradykinin accumulation in the kidney, since the increase in renal blood flow induced by converting enzyme inhibition is associated with an enhanced renal vascular response to AII. When NM are shifted from a low to a high sodium intake, they show more positive sodium balance, gain more weight and increase their blood pressure more--the characteristics of sodium sensitive hypertension. Converting enzyme inhibition corrects their inability to handle a sodium load as it improves renal blood flow, and induces a depressor response that does not correlate with plasma renin activity. Many of these characteristics are shown in a normotensive offspring of essential hypertensives: since sodium handling is genetically determined, this abnormality may represent the inherited renal abnormality. An abnormality in the control of the renal circulation by AII, reversed by converting enzyme inhibition, may represent a fundamental abnormality in the pathogenesis.
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Epstein M, Loutzenhiser R, Levinson R. Spectrum of deranged sodium homeostasis in essential hypertension. Hypertension 1986; 8:422-32. [PMID: 3516871 DOI: 10.1161/01.hyp.8.5.422] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Essential hypertension is thought to produce a uniform exaggerated natriuresis and diuresis. Because validation of this formulation in humans is incomplete, the natriuretic and diuretic responses to acute volume expansion were characterized by using water immersion to the neck. This method provides a volume stimulus identical to that induced by 2 L of saline without plasma compositional change. Twenty-seven subjects with essential hypertension were studied on three occasions in the seated posture while in balance on a 10 mEq Na, 100 mEq K diet: during the seated control study, during 4 hours of head-out immersion, and during saline infusion (2 L/2 hours). Four subjects had exaggerated urinary Na excretion in response to neck immersion (Group 3), and 16 had a normal response (Group 2) indistinguishable from that of 15 previously studied normal subjects. The remaining seven subjects (Group 1) had blunted or absent natriuretic responses compared with that in normal subjects (p less than 0.005). Similar results were obtained with saline administration; cumulative Na excretion in Group 1 was markedly less than that in Group 2 and the normal subjects. The heterogeneity in Na excretion indicates that an exaggerated natriuresis is not a uniform concomitant of essential hypertension. The significant inverse correlation between basal plasma aldosterone level and peak urinary as well as cumulative Na excretion suggests that plasma aldosterone constitutes a determinant of the differing natriuretic responses. In contrast to findings with urinary Na excretion, the diuretic responses of Groups 1 and 2 were identical. The striking dissociation between renal Na and water handling underscores the specificity of the derangement in renal Na handling.
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