In vitro reactions of a cyanocobalamin-cisplatin conjugate with nucleoside monophosphates.

RATIONALE: Cisplatin (CP) is a widely used anticancer drug characterized by toxic side effects that could be alleviated using novel delivery systems including CP prodrugs. The in vitro incubation of a putative prodrug, obtained from cyanocobalamin (CNCbl) and cis-diamminemonochloroplatinum(II) (mCP), with nucleoside monophosphates (NMPs) was investigated. METHODS: The in vitro reactions between the putative prodrug CNCbl-mCP and the NMPs of adenosine (AMP), guanosine (GMP), cytidine (CMP) and uridine (UMP) were carried out in slightly acidic water-methanol solutions at 37°C for 24 h. Each sample was examined using reversed-phase liquid chromatography coupled with electrospray ionization in positive ion mode and tandem mass spectrometry (RPLC/ESI-MS/MS) by collision-induced dissociation in a linear ion-trap mass spectrometer. RESULTS: Seven adducts were recognized as formed by substitution reactions of the chloride ligand in planar CP. Comparison between observed and theoretical isotopic patterns together with MS/MS fragmentation pathways revealed the presence of single or multiple binding sites depending on the NMP involved. The CNCbl-mCP conjugate was found to interact with N7 or O4 atoms of GMP and UMP, respectively, generating single adducts, while two isomeric adducts were observed for CMP. Finally, AMP gave rise to three isomeric adducts. CONCLUSIONS: In agreement with literature data relevant to the interaction between CP and NMPs, the most reactive nucleotides were AMP and GMP. The present RPLC/ESI-MS/MS approach is very promising for investigation of the reactions of CP conjugates with ribonucleotides not only in vitro but also in vivo.

A Case of Adrenal Vein Sampling in Primary Aldosteronism With Homolateral Suppression.

CONTEXT: Adrenal venous sampling (AVS) is regarded as the gold standard for diagnosis of primary aldosteronism (PA) subtypes, although some authors have questioned its diagnostic accuracy and highlighted the lack of standardized procedure protocols and interpretation criteria for AVS. In particular, the usefulness of cosyntropin stimulation and benefit of superselective adrenal vein catheterization have been hotly debated. OBJECTIVE: We report a case that highlights the potential pitfalls of superselective sampling and demonstrates a negligible effect of cosyntropin stimulation on aldosterone secretion in nonadenomatous adrenal tissue when an aldosterone-producing adenoma (APA) is present. INTERVENTION AND RESULTS: A 38-year-old man with PA and a single right macroadenoma underwent AVS at our center. The procedure was performed both under basal conditions and during cosyntropin stimulation. Right adrenal vein angiography demonstrated two branches of the main adrenal vein trunk, one draining the nodule and one draining the right adrenal gland. Hormonal assays confirmed adrenal origin of left-sided and all right-sided samples, and were consistent with lateralization on the right side, with suppression of aldosterone secretion in the left adrenal gland and in the nonadenomatous right adrenal tissue. Cosyntropin-stimulated AVS results were similar to those of the unstimulated procedure. CONCLUSIONS: Cosyntropin stimulation does not significantly affect aldosterone secretion from nonadenomatous adrenal tissue when an APA is present and can therefore be used during AVS for PA. Superselective AVS should be performed with caution and interpreted by expert clinicians.

Prevalence and Clinical Manifestations of Primary Aldosteronism Encountered in Primary Care Practice.

BACKGROUND: Despite being widely recognized as the most common form of secondary hypertension, among the general hypertensive population the true prevalence of primary aldosteronism (PA) and its main subtypes, aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH), remains a matter of debate. OBJECTIVES: This study sought to determine the prevalence and clinical phenotype of PA in a large cohort of unselected patients with hypertension, consecutively referred to our hypertension unit, by 19 general practitioners from Torino, Italy. METHODS: Following withdrawal from all interfering medications, patients were screened for PA using the ratio of serum aldosterone to plasma renin activity. PA was diagnosed according to Endocrine Society guidelines. The diagnosis was confirmed or excluded by an intravenous saline infusion test or captopril challenge test and subtype differentiation was performed by adrenal computed tomography scanning and adrenal vein sampling, using strict criteria to define successful cannulation and lateralization of aldosterone production. RESULTS: A total of 1,672 primary care patients with hypertension (569 newly diagnosed and 1,103 patients already diagnosed with arterial hypertension) were included in the study. A total of 99 patients (5.9%) were diagnosed with PA and conclusive subtype differentiation by adrenal vein sampling was made in 91 patients (27 patients with an APA and 64 patients with BAH). The overall prevalence of PA increased with the severity of hypertension, from 3.9% in stage 1 hypertension to 11.8% in stage 3 hypertension. Patients with PA more frequently displayed target organ damage and cardiovascular events compared with those without PA, independent of confounding variables. CONCLUSIONS: Our results demonstrated that PA is a frequent cause of secondary hypertension, even in the general population of patients with hypertension, and indicates that most of these patients should be screened for PA.

Adrenal vein sampling in primary aldosteronism: towards a standardised protocol.

Primary aldosteronism comprises subtypes that need different therapeutic strategies. Adrenal vein sampling is recognised by Endocrine Society guidelines as the only reliable way to correctly diagnose the subtype of primary aldosteronism. Unfortunately, despite being the gold-standard procedure, no standardised procedure exists either in terms of performance or interpretation criteria. In this Personal View, we address several questions that clinicians are presented with when considering adrenal vein sampling. For each of these questions we provide responses based on the available evidence, and opinions based on our experience. In particular, we discuss the most appropriate way to prepare the patient, whether adrenal vein sampling can be avoided for some subgroups of patients, the use of ACTH (1-24) during the procedure, the most appropriate criteria for interpretation of adrenal vein cannulation and lateralisation, the use of contralateral suppression, and strategies to improve success rates of adrenal vein sampling in centres with little experience.

Effects of slow, controlled breathing on baroreceptor control of heart rate and blood pressure in healthy men.

BACKGROUND: Slow, controlled breathing has been shown by cross-spectral techniques to potentiate arterial baroreflex control of heart rate. However, crucial aspects of the effects of slow breathing on the arterial baroreflex remain unsettled, namely whether the major function of the arterial baroreflex (i.e. the control of blood pressure) is also potentiated and whether baroreflex function is differentially modulated according to the age of the individual. OBJECTIVE: To examine the bradycardic and depressor responses to selective carotid baroreceptor stimulation by the neck chamber technique (-15 and -30 mmHg neck suction) and the cross-spectral R-R interval/systolic blood pressure relationship (alpha index). METHODS: In 24 resting, supine healthy male volunteers (aged 19-66 years, mean +/-SEM 37.5 +/- 3.19 years), blood pressure (Finapres), R-R interval (electrocardiogram) and ventilation (impedance) were recorded continuously. Both assessments were performed during spontaneous breathing and during 6 cycles/min controlled ventilation in random order. RESULTS: The depressor and bradycardic responses to neck suction were significantly larger during slow breathing than in spontaneous breathing (+32 and +85%, respectively; both P < 0.01). The alpha index was also significantly larger during slow breathing (+62%; P < 0.01). Even after the volunteers were divided into older (> 50 years, n = 9) and younger (< 30 years, n = 9) groups, the baroreflex potentiation related to slow breathing was clearcut and significant for both the depressor (+46 and +24% older and younger volunteers; both P < 0.01) and the bradycardic (+130 and +73% older and younger volunteers; both P < 0.01) responses. When the assessment was made by computing the cross-spectral alpha index, a marked potentiation related to slow breathing was observed in younger volunteers (+99%; P < 0.01), whereas in older volunteers only a trend to an enhancement (by 32%; P < 0.055) was observed. CONCLUSIONS: Slow controlled breathing is associated with potentiation of both the depressor and the cardio-inhibitory components of the arterial baroreflex, the potentiation being largely similar regardless of the age of the individual.

Aldosterone suppression on contralateral adrenal during adrenal vein sampling does not predict blood pressure response after adrenalectomy.

CONTEXT: Adrenal vein sampling (AVS) is the only reliable means to distinguish between aldosterone-producing adenoma and bilateral adrenal hyperplasia, the two most common subtypes of primary aldosteronism (PA). AVS protocols are not standardized and vary widely between centers. OBJECTIVE: The objective of the study was to retrospectively investigate whether the presence of contralateral adrenal (CL) suppression of aldosterone secretion was associated with improved postoperative outcomes in patients who underwent unilateral adrenalectomy for PA. SETTING: The study was carried out in eight different referral centers in Italy, Germany, and Japan. PATIENTS: From 585 consecutive AVS in patients with confirmed PA, 234 procedures met the inclusion criteria and were used for the subsequent analyses. RESULTS: Overall, 82% of patients displayed contralateral suppression. This percentage was significantly higher in ACTH stimulated compared with basal procedures (90% vs 77%). The CL ratio was inversely correlated with the aldosterone level at diagnosis and, among AVS parameters, with the lateralization index (P = .02 and P = .01, respectively). The absence of contralateral suppression was not associated with a lower rate of response to adrenalectomy in terms of both clinical and biochemical parameters, and patients with CL suppression underwent a significantly larger reduction in the aldosterone levels after adrenalectomy. CONCLUSIONS: For patients with lateralizing indices of greater than 4 (which comprised the great majority of subjects in this study), CL suppression should not be required to refer patients to adrenalectomy because it is not associated with a larger blood pressure reduction after surgery and might exclude patients from curative surgery.

Diagnosis and treatment of unilateral forms of primary aldosteronism.

Primary aldosteronism (PA) is now recognized as the most frequent form of secondary arterial hypertension. The importance of a correct and prompt diagnosis of PA is determined by its relevant prevalence, its increased cardiovascular risk compared to essential hypertension and by the possibility of reversing this increased risk with a targeted therapy. Surgical treatment of unilateral forms of PA (mainly aldosterone-producing adenomas) is at present recommended in well-selected patients because of its cost-effectiveness. Therefore, subtype differentiation of PA forms is of fundamental importance, and available guidelines recommend contrast-enhanced CT-scanning and adrenal venous sampling (AVS) as the main diagnostic tests for this purpose. In this review, we discuss the value of adrenal non-invasive imaging and AVS, the recent advances in complementary tests and, finally, the available data on the outcome of surgical treatment for PA.

Long-term cardio- and cerebrovascular events in patients with primary aldosteronism.

BACKGROUND: Aldosterone plays a detrimental role on the cardiovascular system and PA patients display a higher risk of events compared with EH. OBJECTIVES: The objectives of the study were to compare cardio- and cerebrovascular events in patients with primary aldosteronism (PA) and matched essential hypertension (EH). METHODS: We retrospectively compared the percentage of patients experiencing events at baseline and during a median follow-up of 12 years in 270 PA patients case-control matched 1:3 with EH patients and in PA subtypes [aldosterone-producing adenoma (n = 57); bilateral adrenal hyperplasia (n = 213)] vs matched EH. RESULTS: A significantly higher number of PA patients experienced cardiovascular events over the entire period of the study (22.6% vs 12.7%, P < .001). At the diagnosis of PA, a higher number of patients had experienced total events (14.1% vs 8.4% EH, P = .007); furthermore, during the follow-up period, PA patients had a higher rate of events (8.5% vs 4.3% EH, P = .008). In particular, stroke and arrhythmias were more frequent in PA patients. During the follow-up, a higher percentage of PA patients developed type 2 diabetes. Parameters that were independently associated with the occurrence of all events were age, duration of hypertension, systolic blood pressure, presence of diabetes mellitus, and PA diagnosis. After division into PA subtypes, patients with either aldosterone-producing adenoma or bilateral adrenal hyperplasia displayed a higher rate of events compared with the matched EH patients. CONCLUSIONS: This study demonstrates in a large population of patients the pathogenetic role of aldosterone excess in the cardiovascular system and thus the importance of early diagnosis and targeted PA treatment.

Effect of adrenocorticotropic hormone stimulation during adrenal vein sampling in primary aldosteronism.

Adrenal vein sampling (AVS) is fundamental for subtype diagnosis in patients with primary aldosteronism. AVS protocols vary between centers, especially for diagnostic indices and for use of adrenocorticotropic hormone (ACTH) stimulation. We investigated the role of both continuous ACTH infusion and bolus on the performance and interpretation of AVS in a sample of 76 patients with confirmed primary aldosteronism. In 36 primary aldosteronism patients, AVS was performed both under basal conditions and after continuous ACTH infusion, and in 40 primary aldosteronism patients, AVS was performed both under basal conditions and after ACTH IV bolus. Both ACTH protocols determined an increase in the rate of successful cannulation of the adrenal veins. Both ACTH infusion and bolus determined a significant increase in selectivity index for the right adrenal vein and ACTH bolus for the left adrenal vein. Lateralization index was not significantly different after continuous ACTH infusion and IV bolus. In 88% and 78% of the patients, the diagnosis obtained was the same before and after ACTH infusion and IV bolus, respectively. However, the reproducibility of the diagnosis was reduced using less stringent criteria for successful cannulation of the adrenal veins. This study shows that ACTH use during AVS may be of help for centers with lower success rates, because a successful adrenal cannulation is more easily obtained with this protocol; moreover, this technique performs at least as well as the unstimulated strategy and in some cases may be even better. Stringent criteria for cannulation should be used to have a high consistency of the diagnosis.

KCNJ5 mutations in European families with nonglucocorticoid remediable familial hyperaldosteronism.

Primary aldosteronism is the most frequent cause of endocrine hypertension. Three forms of familial hyperaldosteronism (FH) have been described, named FH-I to -III. Recently, a mutation of KCNJ5 has been shown to be associated with FH-III, whereas the cause of FH-II is still unknown. In this study we searched for mutations in KCNJ5 in 46 patients from 21 families with FH, in which FH-I was excluded. We identified a new germline G151E mutation in 2 primary aldosteronism-affected subjects from an Italian family and 3 somatic mutations in aldosterone-producing adenomas, T158A described previously as a germline mutation associated with FH-III, and G151R and L168R both described as somatic mutations in aldosterone-producing adenoma. The phenotype of the family with the G151E mutation was remarkably milder compared with the previously described American family, in terms of both clinical and biochemical parameters. Furthermore, patients with somatic KCNJ5 mutations displayed a phenotype indistinguishable from that of sporadic primary aldosteronism. The functional characterization of the effects of the G151E mutation in vitro showed a profound alteration of the channel function, with loss of K(+) selectivity, Na(+) influx, and membrane depolarization. These alterations have been postulated to be responsible for voltage gate Ca(2+) channel activation, increase in cytosolic calcium, and stimulation of aldosterone production and adrenal cell proliferation. In conclusion, we describe herein a new mutation in the KCNJ5 potassium channel associated with FH-III, responsible for marked alterations of channel function but associated with a mild clinical and hormonal phenotype.

Concurrent primary aldosteronism and subclinical cortisol hypersecretion: a prospective study.

BACKGROUND: Primary aldosteronism is the most frequent cause of secondary hypertension and is responsible for an increased risk of cardiometabolic complications. A concomitant subtle cortisol hyperproduction could enhance cardiovascular risk. We prospectively estimated the occurrence of subclinical hypercortisolism in primary aldosteronism patients. METHODS: In a large population of hypertensive patients without clinical signs of hypercortisolism, 76 consecutive patients with primary aldosteronism were investigated. Differential diagnosis between unilateral and bilateral aldosterone hypersecretion was made by computed tomography/MRI and/or adrenal venous sampling (AVS). Subclinical hypercortisolism was defined as failure to suppress plasma cortisol to less than 50 nmol/l after 1 mg-overnight dexamethasone, used as screening test, and at least one of two other abnormal hormonal parameters, that is, adrenocorticotrophin (ACTH) less than 2 pmol/l and urinary cortisol more than 694 nmol/24 h. RESULTS: Three out of 76 patients had postdexamethasone plasma cortisol more than 50 nmol/l. Only one also showed low-normal ACTH and mildly elevated urinary cortisol. The patient had a right 4 cm adrenal mass. Laparoscopic adrenalectomy was followed by short-term steroid replacement to prevent adrenal insufficiency. In-situ hybridization showed CYP11B1 expression exclusively in tumoral tissue, whereas CYP11B2 was expressed only in a peritumoral region composed of zona glomerulosa-like cells, suggesting the co-existence of a cortisol-producing adenoma and an aldosterone-producing hyperplasia in the same adrenal. The restoration of hormone abnormalities to normal levels was confirmed at 12 months of follow-up. CONCLUSION: Concurrent aldosterone and subclinical cortisol hypersecretion seems to be a rare event in primary aldosteronism patients; however, its detection by appropriate testing is important to avoid AVS misinterpretation.

Prevalence and characteristics of familial hyperaldosteronism: the PATOGEN study (Primary Aldosteronism in TOrino-GENetic forms).

Primary aldosteronism (PA) is the most frequent cause of secondary hypertension, and patients display an increased prevalence of cardiovascular events compared with essential hypertensives. To date, 3 familial forms of PA have been described and termed familial hyperaldosteronism types I, II, and III (FH-I to -III). The aim of this study was to investigate the prevalence and clinical characteristics of the 3 forms of FH in a large population of PA patients. Three-hundred consecutive PA patients diagnosed in our unit were tested by long-PCR of the CYP11B1/CYP11B2 hybrid gene that causes FH-I, and all of the available relatives of PA patients were screened to confirm or exclude PA and, thus, FH-II. Urinary 18-hydroxycortisol and 18-oxocortisol were measured in all of the familial PA patients. Two patients were diagnosed with FH-I (prevalence: 0.66%), as well as 21 of their relatives, and clinical phenotypes of the 2 affected families varied markedly. After exclusion of families who refused testing and those who were not informative, 199 families were investigated, of which 12 were diagnosed with FH-II (6%) and an additional 15 individuals had confirmed PA; clinical and biochemical phenotypes of FH-II families were not significantly different from sporadic PA patients. None of the families displayed a phenotype compatible with FH-III diagnosis. Our study demonstrates that familial forms of hyperaldosteronism are more frequent than previously expected and reinforces the recommendation of the Endocrine Society Guidelines to screen all first-degree hypertensive relatives of PA patients.

Enhanced baroreceptor control of the cardiovascular system by polyunsaturated Fatty acids in heart failure patients.

OBJECTIVES: The intention of this study was to test the hypothesis that, in heart failure patients, dietary supplementation of polyunsaturated fatty acids (PUFA) enhances arterial baroreceptor control of the cardiovascular system. BACKGROUND: Administration of PUFA reduces the risk of life-threatening arrhythmias in patients surviving myocardial infarction. This might result from potentiation of arterial baroreflexes, but whether or not PUFA enhance baroreflex function has never been studied in humans. METHODS: Patients with post-myocardial infarction left ventricular dysfunction underwent beat-to-beat blood pressure (BP) (Finapres, Ohmeda Inc., Englewood, Colorado) and R-R interval (electrocardiogram) recording; baroreceptor reflexes were assessed from the bradycardic and depressor responses to graded neck suction (NS) as well as by computation of the alpha "spontaneous" baroreflex sensitivity index. Assessments were repeated after prolonged treatment with PUFA (2 g/die, n = 15) or placebo (n = 10). RESULTS: Baseline BP and R-R interval were unaffected by PUFA. Both reflex depressor and bradycardic responses to NS increased after PUFA (respectively from -0.09 +/- 0.01 to -0.16 +/- 0.01 mm Hg x mm Hg(-1), p < 0.01, and from 1.25 +/- 0.9 to 1.76 +/- 1.1 ms x mm Hg(-1), p < 0.04) but not after placebo. The spontaneous baroreflex sensitivity increased in the PUFA (from 8.99 +/- 1.4 to 12.2 +/- 1.2 ms x mm Hg(-1), p < 0.02) but not in the placebo group. Polyunsaturated fatty acids (but not placebo) treatment also significantly increased R-R interval total variance and low-frequency and high-frequency spectral powers. CONCLUSIONS: Dietary PUFA supplementation markedly potentiates baroreflex function and enhances heart rate variability in patients with stable congestive heart failure.