High Blood Pressure Is Associated with Tubulointerstitial Damage along with Glomerular Damage in Glomerulonephritis. A large Cohort Study.

The key role of arterial hypertension in chonic kidney disease (CKD) progression is widely recognized, but its contribution to tubulointerstitial damage (TID) in glomerulonephritis (GN) remains uncertain. Hence, the objective of this study is to clarify whether TID is associated with glomerular damage, and whether the damage at the tubulointerstitial compartment is more severe in hypertensive patients. The study included retrospectively consecutive patients referred to the Nephrology Unit with diagnoses of primary glomerulonephritis, lupus nephritis (LN), and nephroangiosclerosis (NAS) at biopsy. At least six glomeruli per biopsy were analysed through light and immunofluorescence microscopy. Global glomerulosclerosis (GGS%), TID, and arteriolar hyalinosis (AH) were used as markers of CKD severity. Of the 448 patients of the cohort, 403 received a diagnosis of GN, with the remaining being diagnosed with NAS. Hypertension was found in 52% of the overall patients, with no significant differences among those with GN, and reaching 88.9% prevalence rate in NAS. The hypertensive patients with GN had more marked damage in glomerular and tubular compartments than normotensives independently of the amount of proteinuria. Moreover, hypertension and GGS% were found to be strongly associated with TID in GN. In GN patients, not only the severity of glomerular damage but also the extent of TID was associated with high blood pressure.

Disease monitoring of Primary Aldosteronism.

Primary aldosteronism (PA) is a highly prevalent cause of arterial hypertension featuring excess cardiovascular events. A timely diagnosis and treatment of PA cures hyperaldosteronism and can provide resolution or improvement of arterial hypertension, even when the latter is resistant to drug treatment. Accordingly, strategies to screen early and widely the hypertensive patients for PA by means of simplified diagnostic algorithms are justified. Such strategies are particularly beneficial in subgroups of hypertensive patients, who are at the highest cardiovascular risk. Broadening of screening strategies means facing with an increased number of patients where monitoring the disease becomes necessary. Hence, after identification of the surgically and non surgically curable cases of PA and implementation of targeted treatment physicians are faced with the challenges of follow-up, which are scantly discussed in the literature. Hence, the purpose of this paper is to provide some recommendations on how to optimize the monitoring of patients in whom the PA subtype has been diagnosed and treatment, either with unilateral laparoscopic adrenalectomy or medically, has been instituted.

Role of estrogen receptors in modulating aldosterone biosynthesis and blood pressure.

Blood pressure is lower in premenopausal women than in age-matched men; after menopause blood pressure values and the prevalence of hypertension show opposite trends indicating that estrogens contribute to maintaining normal blood pressure values in women. In experimental studies menopause increases aldosterone levels, an effect alleviated by estrogen treatment. We have recently discovered a role of estrogen receptors (ER) in controlling aldosterone biosynthesis in the human adrenocortical zona glomerulosa, which expresses both the classical ERα and ß receptors and G protein-coupled estrogen receptor (GPER). We have also identified that GPER mediates an aldosterone-induced aldosterone response. We found that 17 ß-estradiol exerts a dual effect: it blunts aldosterone production via ERß, but displays a potent aldosterone secretagogue effect via GPER activation after ERß blockade. Thus, in premenopausal women high estrogen levels might tonically blunt aldosterone synthesis via ERß, thereby maintaining normal blood pressure; after menopause loss of this estrogen-mediated inhibition can contribute to increasing blood pressure via GPER-mediated aldosterone release. The additional findings that GPER mediates an aldosterone-induced stimulation of aldosterone biosynthesis and that GPER predominates in aldosterone-producing adenomas strongly involves this receptor in the pathophysiology of primary aldosteronism. Our purpose here was to provide an update on estrogen receptor function in the normal adrenal cortex and its relevance for the sex differences in blood pressure in light of the newly discovered role of GPER in regulating aldosterone synthesis. The implications of the novel knowledge for the treatment of estrogen-dependent malignancies with ER modulators are also discussed.

The Key Role of Epithelial to Mesenchymal Transition (EMT) in Hypertensive Kidney Disease.

Accumulating evidence indicates that epithelial-to-mesenchymal transition (EMT), originally described as a key process for organ development and metastasis budding in cancer, plays a key role in the development of renal fibrosis in several diseases, including hypertensive nephroangiosclerosis. We herein reviewed the concept of EMT and its role in renal diseases, with particular focus on hypertensive kidney disease, the second leading cause of end-stage renal disease after diabetes mellitus. After discussing the pathophysiology of hypertensive nephropathy, the 'classic' view of hypertensive nephrosclerosis entailing hyalinization, and sclerosis of interlobular and afferent arterioles, we examined the changes occurring in the glomerulus and tubulo-interstitium and the studies that investigated the role of EMT and its molecular mechanisms in hypertensive kidney disease. Finally, we examined the reasons why some studies failed to provide solid evidence for renal EMT in hypertension.

The Biology of Normal Zona Glomerulosa and Aldosterone-Producing Adenoma: Pathological Implications.

The identification of several germline and somatic ion channel mutations in aldosterone-producing adenomas (APAs) and detection of cell clusters that can be responsible for excess aldosterone production, as well as the isolation of autoantibodies activating the angiotensin II type 1 receptor, have rapidly advanced the understanding of the biology of primary aldosteronism (PA), particularly that of APA. Hence, the main purpose of this review is to discuss how discoveries of the last decade could affect histopathology analysis and clinical practice. The structural remodeling through development and aging of the human adrenal cortex, particularly of the zona glomerulosa, and the complex regulation of aldosterone, with emphasis on the concepts of zonation and channelopathies, will be addressed. Finally, the diagnostic workup for PA and its subtyping to optimize treatment are reviewed.

The subtyping of primary aldosteronism by adrenal vein sampling: sequential blood sampling causes factitious lateralization.

BACKGROUND: The pulsatile secretion of adrenocortical hormones and a stress reaction occurring when starting adrenal vein sampling (AVS) can affect the selectivity and also the assessment of lateralization when sequential blood sampling is used. We therefore tested the hypothesis that a simulated sequential blood sampling could decrease the diagnostic accuracy of lateralization index for identification of aldosterone-producing adenoma (APA), as compared with bilaterally simultaneous AVS. METHODS AND RESULTS: In 138 consecutive patients who underwent subtyping of primary aldosteronism, we compared the results obtained simultaneously bilaterally when starting AVS (t-15) and 15 min after (t0), with those gained with a simulated sequential right-to-left AVS technique (R ⇒ L) created by combining hormonal values obtained at t-15 and at t0. The concordance between simultaneously obtained values at t-15 and t0, and between simultaneously obtained values and values gained with a sequential R ⇒ L technique, was also assessed. We found a marked interindividual variability of lateralization index values in the patients with bilaterally selective AVS at both time point. However, overall the lateralization index simultaneously determined at t0 provided a more accurate identification of APA than the simulated sequential lateralization indexR ⇒ L (P = 0.001). Moreover, regardless of which side was sampled first, the sequential AVS technique induced a sequence-dependent overestimation of lateralization index. While in APA patients the concordance between simultaneous AVS at t0 and t-15 and between simultaneous t0 and sequential technique was moderate-to-good (K = 0.55 and 0.66, respectively), in non-APA patients, it was poor (K = 0.12 and 0.13, respectively). CONCLUSION: Sequential AVS generates factitious between-sides gradients, which lower its diagnostic accuracy, likely because of the stress reaction arising upon starting AVS.

Endothelial factors in the pathogenesis and treatment of chronic kidney disease Part II: Role in disease conditions: a joint consensus statement from the European Society of Hypertension Working Group on Endothelin and Endothelial Factors and the Japanese Society of Hypertension.

: After examining in Part I the general mechanisms of endothelial cell injury in the kidney, the Working Group on Endothelin and Endothelial Factors of the European Society of Hypertension and the Japanese Society of Hypertension will herein review current knowledge on the role of endothelial dysfunction in multiple disease conditions that affect the kidney, including diabetes mellitus, preeclampsia, solid organ transplantation, hyperhomocysteinemia and antiangiogenic therapy in cancer. The few available randomized controlled clinical trials specifically designed to evaluate strategies for correcting endothelial dysfunction in patients with hypertension and/or chronic kidney disease are also discussed alongside their cardiovascular and renal outcomes.

Endothelin-1 Drives Epithelial-Mesenchymal Transition in Hypertensive Nephroangiosclerosis.

BACKGROUND: Tubulointerstitial fibrosis, the final outcome of most kidney diseases, involves activation of epithelial mesenchymal transition (EMT). Endothelin-1 (ET-1) activates EMT in cancer cells, but it is not known whether it drives EMT in the kidney. We therefore tested the hypothesis that tubulointerstitial fibrosis involves EMT driven by ET-1. METHODS AND RESULTS: Transgenic TG[mRen2]27 (TGRen2) rats developing fulminant angiotensin II-dependent hypertension with prominent cardiovascular and renal damage were submitted to drug treatments targeted to ET-1 and/or angiotensin II receptor or left untreated (controls). Expressional changes of E-cadherin and α-smooth muscle actin (αSMA) were examined as markers of renal EMT. In human kidney HK-2 proximal tubular cells expressing the ETB receptor subtype, the effects of ET-1 with or without ET-1 antagonists were also investigated. The occurrence of renal fibrosis was associated with EMT in control TGRen2 rats, as evidenced by decreased E-cadherin and increased αSMA expression. Irbesartan and the mixed ET-1 receptor antagonist bosentan prevented these changes in a blood pressure-independent fashion (P < 0.001 for both versus controls). In HK-2 cells ET-1 blunted E-cadherin expression, increased αSMA expression (both P < 0.01), collagen synthesis, and metalloproteinase activity (P < 0.005, all versus untreated cells). All changes were prevented by the selective ETB receptor antagonist BQ-788. Evidence for involvement of the Rho-kinase signaling pathway and dephosphorylation of Yes-associated protein in EMT was also found. CONCLUSIONS: In angiotensin II-dependent hypertension, ET-1 acting via ETB receptors and the Rho-kinase and Yes-associated protein induces EMT and thereby renal fibrosis.

GPER-1 and estrogen receptor-ß ligands modulate aldosterone synthesis.

Fertile women have lower blood pressure and cardiovascular risk than age-matched men, which suggests that estrogens exert cardiovascular protective effects. However, whether 17 ß-estradiol (E2) blunts aldosterone secretion, and thereby affects the gender dimorphism of blood pressure, is unknown. We therefore sought for the estrogen receptor (ER) subtypes in human adrenocortical tissues ex vivo by performing gene and protein expression studies. We also investigated the effect of E2 on aldosterone synthesis and the involved receptors through in vitro functional experiments in the adrenocortical cells HAC15. We found that in the human adrenal cortex and aldosterone-producing adenoma cells, the most expressed ERs were the ERß and the G protein-coupled receptor-1 (GPER-1), respectively. After selective ERß blockade, E2 (10 nmol/L) markedly increased both the expression of aldosterone synthase and the production of aldosterone (+5- to 7-fold vs baseline, P < .001). Under the same condition, the GPER-1 receptor agonist 1-[4-(6-bromo-benzo (1, 3)dioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c] quinolin-8-yl]-ethanone (G-1) (10 nmol/L) mimicked this effect, which was abrogated by cotreatment with either the GPER-1 receptor antagonist (3aS*,4R*,9bR*)-4-(6-Bro-mo-1,3-benzodioxol-5-yl)-3a,4,5,9b-3H-cyclopenta[c]quinoline (G-15), or a selective protein kinase A inhibitor 8-Bromo-2-monobutyryladenosine-3,5-cyclic mono-phosphorothioate, Rp-isomer. Silencing of the ERß significantly raised aldosterone synthase expression and aldosterone production. Conversely, silencing of the GPER-1 lowered aldosterone synthase gene and protein expression. Moreover, it blunted the stimulatory effect of E2 on aldosterone synthase that was seen during ERß blockade. These results support the conclusion that in humans, E2 inhibits aldosterone synthesis by acting via ERß. Pharmacologic disinhibition of ERß unmasks a potent secretagogue effect of E2 that involves GPER-1 and protein kinase A signaling.

KCNJ5 gene somatic mutations affect cardiac remodelling but do not preclude cure of high blood pressure and regression of left ventricular hypertrophy in primary aldosteronism.

OBJECTIVE: Aldosterone exerts detrimental cardiovascular effects, and patients with an aldosterone-producing adenoma (APA) carrying somatic mutations in the KCNJ5 K(+) channel (mutAPA) have higher plasma aldosterone concentration than wild-type APA (wtAPA) patients. We therefore investigated whether mutAPA patients develop a more prominent cardiovascular damage than wtAPA patients. METHODS AND FINDINGS: From 257 consecutive primary aldosteronism patients, we identified 176 who had both a diagnosis of APA by the 'four corners' criteria and high-quality echocardiographic data. Of them, 129 with KCNJ5 sequencing information and long-term follow-up data were compared for echocardiographic changes according to presence (mutAPA, 26%) or absence (wtAPA, 74%) of the KCNJ5 mutations. At baseline, the mutAPA were similar to the wtAPA for blood pressure (BP) and need for antihypertensive medications. However, they had higher left ventricular mass index (59 ± 19 vs. 51 ± 13 g/h(2.7); P < 0.05) and plasma aldosterone concentration [49 (32-68) vs. 36 (25-52) ng/dl); P = 0.048] than the wtAPA patients. In spite of their more prominent cardiac involvement, the mutAPA patients exhibited a fall of BP and plasma aldosterone similar to wtAPA, and a regression of left ventricular mass index. CONCLUSIONS: Compared to the wild-type APA patients those with KCNJ5 mutations showed more prominent cardiovascular damage. Notwithstanding this, their chances of being cured from the hyperaldosteronism and the high BP, and of regression of left ventricular hypertrophy after adrenalectomy, were not compromised by the presence of these mutations.

Lower expression of the TWIK-related acid-sensitive K+ channel 2 (TASK-2) gene is a hallmark of aldosterone-producing adenoma causing human primary aldosteronism.

CONTEXT: The molecular mechanisms of primary aldosteronism, a common cause of human hypertension, are unknown, but alterations of K(+) channels can play a key role. OBJECTIVE: The objective of the study was to investigate the following: 1) the expression of the Twik-related acid-sensitive K(+) channels (TASK) in aldosterone producing adenomas (APAs); 2) the role of TASK-2 in aldosterone synthesis; and 3) the determinants of TASK-2-blunted expression in APAs. DESIGN: We analyzed the transcriptome and the microRNA profiles of 32 consecutive APAs and investigated the protein expression and localization of TASK-2 in APA and adrenocortical cell lines (H295R and HAC15) using immunoblotting and confocal microscopy. The functional effect of TASK-2 blunted activity caused by a dominant-negative mutation on steroidogenic enzymes, and aldosterone production was also assessed. TASK-2 regulation by selected microRNA was studied by a luciferase assay. RESULTS: TASK-2 was consistently less expressed at the transcript and protein levels in APAs than in the normal human adrenal cortex. H295R cell transfection with a TASK-2 dominant-negative mutant construct significantly increased the aldosterone production by 153% and the gene expression of aldosterone synthase (CYP11B2, gene expression fold change 3.1 vs control, P < .05) and the steroidogenic acute regulatory protein (gene expression fold change 1.8 vs control, P < .05). Two microRNAs, hsa-miR-23 and hsa-miR-34, were found to decrease the TASK-2 expression by binding to the 3' untranslated region of the TASK-2 gene. CONCLUSIONS: The TASK-2 channel lower expression represents a hallmark of APA and is associated with a higher expression of hsa-miR-23 and hsa-miR-34. The ensuing blunted TASK-2 activity increased the production of aldosterone in vitro and the expression of steroidogenic acute regulatory protein and CYP11B2. Hence, the lower expression of TASK-2 channel in APA cells can explain high aldosterone secretion in human primary aldosteronism despite the suppression of angiotensin II, hypertension, and hypokalemia.

Somatic mutations in the KCNJ5 gene raise the lateralization index: implications for the diagnosis of primary aldosteronism by adrenal vein sampling.

CONTEXT: Somatic mutations in the selectivity filter of KCNJ5 K(+) channel were found to be associated with higher plasma aldosterone concentrations in the patients with an aldosterone-producing adenoma (APA). OBJECTIVE: We investigated whether plasma aldosterone levels and the lateralization index are higher from the side with the APA with the mutation, as compared with those without the mutation. DESIGN: From 170 consecutive APA patients with comprehensive clinical and KCNJ5 data and a conclusive diagnosis, we recruited 91 patients with adrenal vein sampling and follow-up data. We measured CYP11B1 and CYP11B2 mRNA in APA tissue and plasma aldosterone (PAC) and plasma cortisol concentrations (PCC) in adrenal vein blood. To determine whether KCNJ5 mutations affected aldosterone output from the APA, we calculated the lateralization index (defined as the ratio of PAC to PCC at the APA side over the PAC to PCC ratio at the contralateral side). We also calculated two indexes of the aldosterone production from the APA side and the contralateral suppression index. RESULTS: The mRNA content of CYP11B2, but not of CYP11B1, and, accordingly, the lateralization index was higher (29.9 ± 7.4 vs. 10.3 ± 3.6, P < 0.02) in the APA with the mutation than in the APA without the mutation. CONCLUSIONS: APA patients with the somatic KCNJ5 mutations showed a higher production of aldosterone than those without such mutations, which translates in a higher lateralization index. Thus, they are more likely to be identified at adrenal vein sampling and therefore to receive adrenalectomy.

A stress reaction affects assessment of selectivity of adrenal venous sampling and of lateralization of aldosterone excess in primary aldosteronism.

BACKGROUND: A stress reaction involving increased cortisol release, which has not been documented thus far, might affect the assessment of selectivity of catheterization during adrenal venous sampling (AVS). OBJECTIVE: To investigate whether an ACTH-driven cortisol release occurs during AVS and whether it influences the assessment of selectivity by the step-up of cortisol (plasma cortisol concentrations, PCC) between the adrenal vein blood (PCC(SIDE)) and the inferior vena cava (PCC(IVC)), e.g. the selectivity index (SI). DESIGN AND METHODS: We determined the SI in samples obtained simultaneously at starting AVS (t-15) and again after 15  min (t0) in 34 consecutive patients with proven aldosterone-producing adenoma. We then calculated the SI with PCC(SIDE) obtained at t-15 and at t0, and the PCC(IVC) values obtained at the different time point, thus simulating sequential AVS. RESULTS: The PCC(SIDE) and the SI fell significantly from t-15 to t0 on both the sides. When PCC(SIDE) obtained at t-15 was combined with PCC(IVC) at t0, the SI values were higher than those obtained with simultaneously drawn samples. This led to label as selective more AVS studies than with bilaterally simultaneous data, especially when using higher cutoffs for the SI. CONCLUSIONS: A transient increase in cortisol release from both adrenal glands occurs in the majority of the patients who undergo AVS. This stress reaction can influence the assessment of both the selectivity of the catheterization during the sequential AVS technique and the lateralization of aldosterone excess.

Prevalence, clinical, and molecular correlates of KCNJ5 mutations in primary aldosteronism.

Primary aldosteronism is the most common form of secondary hypertension. Mutations in the KCNJ5 gene have been described recently in aldosterone-producing adenomas (APAs). The aim of this study was to investigate the prevalence of KCNJ5 mutations in unselected patients with primary aldosteronism and their clinical, biological and molecular correlates. KCNJ5 sequencing was performed on somatic (APA, n=380) and peripheral (APA, n=344; bilateral adrenal hyperplasia, n=174) DNA of patients with primary aldosteronism, collected through the European Network for the Study of Adrenal Tumors. Transcriptome analysis was performed in 102 tumors. Somatic KCNJ5 mutations (p.Gly151Arg or p.Leu168Arg) were found in 34% (129 of 380) of APA. They were significantly more prevalent in females (49%) than males (19%; P<10(-3)) and in younger patients (42.1±1.0 versus 47.6±0.7 years; P<10(-3)) and were associated with higher preoperative aldosterone levels (455±26 versus 376±17 ng/L; P=0.012) but not with therapeutic outcome after surgery. Germline KCNJ5 mutations were found neither in patients with APA nor those with bilateral adrenal hyperplasia. Somatic KCNJ5 mutations were specific for APA, because they were not identified in 25 peritumoral adrenal tissues or 16 cortisol-producing adenomas. Hierarchical clustering of transcriptome profiles showed that APAs with p.Gly151Arg or p.Leu168Arg mutations were indistinguishable from tumors without KCNJ5 mutations. In conclusion, although a large proportion of sporadic APAs harbors somatic KCNJ5 mutations, germline mutations are not similarly causative for bilateral adrenal hyperplasia. KCNJ5 mutation carriers are more likely to be females; younger age and higher aldosterone levels at diagnosis suggest that KCNJ5 mutations may be associated with a more florid phenotype of primary aldosteronism.

Mild hyperparathyroidism: a novel surgically correctable feature of primary aldosteronism.

BACKGROUND: The parathyroid hormone (PTH) stimulates aldosterone secretion and cell proliferation in human adrenocortical cells; moreover, in rats hyperaldosteronism was associated with hyperparathyroidism. Hence, PTH could drive aldosterone excess in human primary aldosteronism. METHOD: To test this hypothesis, we recruited 105 consecutive hypertensive patients, of whom 44 had primary aldosteronism due to an aldosterone-producing adenoma (APA) and 61 had primary (essential) hypertension. We measured the plasma levels of (1-84)-PTH, 25(OH)D, 1,25(OH)2D, and serum Ca (total and ionized), inorganic P, Mg, K, and the 24-h urinary excretion of Ca, P, and deoxypyridinoline. In primary aldosteronism patients, these measurements were repeated after adrenalectomy or mineralocorticoid receptor blockade. We also sought for PTH receptor (PTHR-1) mRNA and protein in APA tissue. RESULTS: Compared with primary (essential) hypertension patients, those with primary aldosteronism showed significantly higher plasma PTH (+31%), despite comparable urinary Ca excretion and similarly deficient 25(OH) vitamin D levels. In APA patients, who showed the PTHR-1 transcript and protein in tumor tissue, adrenalectomy normalized PTH levels (from 118 ±â€Š13 to 76 ±â€Š12 ng/l; P = 0.002) and increased ionized Ca(from 1.17 ±â€Š0.04 to 1.22 ±â€Š0.03 mmol/l; P < 0.001). The slope of the inverse PTH/ionized Ca relationship was steeper in primary aldosteronism than in primary (essential) hypertension, but normalized after adrenalectomy. CONCLUSION: Hence, in primary aldosteronism an increased sensitivity of parathyroid cells to Ca lowering leads to an increase of PTH. This subtle hyperparathyroidism by acting on PTHR-1 in APA might contribute to maintaining hyperaldosteronism despite suppression of angiotensin II formation.

Drug-related hypertension and resistance to antihypertensive treatment: a call for action.

Several drugs can cause hypertension and/or blunt the effect of antihypertensive treatment. They can exacerbate a previously well controlled hypertension and/or render it resistant to therapy. Accordingly, drugs represent a common cause of resistance of hypertension to treatment. Identification of drug-related hypertension can be achieved with a thorough medical history targeted to ascertain concurrent therapies that are prescribed for conditions other than cardiovascular diseases. This can avoid prescribing a more aggressive antihypertensive treatment and may prevent embarking in costly and sometimes invasive diagnostic procedures. Drugs that commonly raise blood pressure include NSAIDs, steroids, oestroprogestinic agents, immunosuppressants, erythropoietin, inhibitors of angiogenesis, anti-HIV agents, and also some high-density lipoprotein-raising agents. As withdrawal of the offending drug is often impracticable, knowledge of the mechanism(s) by which each drug exerts its pressor effects may help selecting the most effective treatment. Purpose of this review is to examine the most common causes of resistant hypertension that are due to drugs or abuse of substances along with their underlying pathophysiological mechanisms. The strategy for selecting the most appropriate treatment and the reasons for 'a call of action' of research in this area are also examined.