Normal Plasma Renin Activity Research Articles

6661 Critical Limb Ischemia - An Unusual Presentation Of A Pheochromocytoma

Abstract Disclosure: S. Hassan: None. Background: Pheochromocytomas can lead to vasoconstriction and its various clinical manifestations due to excess catecholamine release. Critical limb ischemia as a clinical manifestation of pheochromocytoma has been reported sparsely. Clinical Case: A 43 year old female with a past medical history of type 2 diabetes mellitus, Turner syndrome, and hypertension presented to the emergency department with acute on chronic left leg pain. She underwent workup with a CT angiography of the abdomen with runoff for evaluation of her vessels, which revealed an occlusion of her left superficial femoral artery with chronic stenosis of the right femoral system. Multiple unsuccessful attempts were made at revascularization of her left lower extremity, including femoropopliteal bypass, with eventual left above knee amputation, multiple fasciotomies, and angiogram and stenting of multiple vessels. The patient was on a combined OCP (norethindrone-ethinyl estradiol) for hormone replacement for Turner syndrome for the past 30 years, and did not have a personal or family history of clotting disorders. She underwent a hypercoagulable workup which was negative. Echocardiogram was negative for thrombi and was otherwise unremarkable. Incidentally discovered on her initial CT angiography was a heterogeneously enhancing right adrenal mass, which was further delineated on a dedicated CT of the adrenals, which showed a 3.7 cm right adrenal mass with pre-contrast Hounsfield units measuring 46. Biochemical workup revealed a normal plasma renin activity and aldosterone, plasma metanephrine elevated to 5.20 nmol/L (range 0.00 – 0.49 nmol/L), plasma normetanephrine elevated to 4.95 nmol/L (range 0.00 – 0.89 nmol/L), 24 hour urine metanephrine elevated to 3830 ug/d (range 36-229 ug/d), and 24 hour urine normetanephrine 1733 ug/d (range 95 – 650 ug/d). She reports a diagnosis of hypertension at age 36, with no secondary workup pursued; she had suboptimal control on three separate medications, lisinopril, metoprolol, and hydrochlorothiazide. Her blood pressure and heart rate were noted to be labile during her aforementioned surgery. Alpha blockade with doxazosin was started based on her significantly elevated plasma and urine metanephrines and normetanephrines, with improvement in her blood pressure control. She was not found to have a definitive cause of her critical limb ischemia; she was noted to have atherosclerosis in the vessels of her lower extremities, and her chronic oral contraceptive use may also have played a role. However, OCPs are often reported to cause venous rather than arterial thrombi. Therefore, it can be inferred that the catecholamine excess from her presumed pheochromocytoma caused vasoconstriction which may have played a role in the development of her critical limb ischemia. Conclusion: Catecholamine excess that is resultant from a pheochromocytoma may manifest as critical limb ischemia. Presentation: 6/1/2024

Clinical features, laboratory findings and treatment of juxtaglomerular cell tumors: a systemic review.

Juxtaglomerular cell tumors (JGCTs) or reninoma are rare kidney tumors leading to secondary hypertension, and the non-specific clinical manifestations bring about challenges to the diagnosis. This study is to summarize the clinical features, laboratory findings, and treatment of JGCTs. The PubMed, EMBASE database, and manual search were utilized to find all cases, and 158 reports containing 261 patients were identified. Data on patients' demographics, clinical features, diagnostic methods, and treatment options were collected and analyzed. JGCTs occurred predominantly in female patients (female to male ratio, 2.1:1). The median age of patients was 25 years (IQR:18-34 years). Hypertension (97.24%) was the cardinal manifestation. Hypokalemia was reported in 78.71% (159/202) of subjects, and normal serum potassium accounted for 20.79% (42/202). In cases with assessed plasma renin activity (PRA) levels, the median PRA was 7.89 times the upper limit of normal (IQR:3.58-14.41), and 3.82% (5/131) of cases in the normal range. Tumors were detected in 97.8% (175/179) computed tomography (CT), 94.7% (72/76) magnetic resonance imaging (MRI), and 81.5% (110/135) ultrasound, respectively. For 250/261 patients undergoing surgical procedures, 89.14% (197/221), 94.94% (150/158), and 100% (131/131) of patients were restored to normal blood pressure, PRA, and serum potassium, respectively. JGCTs are commonly associated with hypertension, hypokalemia, and hyperreninemia, whereas patients with normotension, normokalemia, and PRA should be systematically pursued after drug-elution lasting for 2 weeks. CT and MRI are more sensitive imaging diagnostic methods. The blood pressure and biochemical parameters of most patients returned to normal after surgery.

Abstract #1400950: Chiari I Malformation with Concomitant Nonfunctioning Pituitary and Adrenal Tumors

Chiari I malformation (CM1) is a rare finding with an incidence ranging from 3.3 to 8.2 per 100000. CM1 has been described with growth hormone secreting pituitary adenomas, and with EPAS1 gain-of-function mutation syndrome with multiple paragangliomas/pheochromocytomas, somatostatinoma, and polycythemia. There is only one case report in the literature describing a nonfunctional pituitary adenoma with CM1. We describe the first reported case of a patient with CM1 with concomitant nonfunctional pituitary and adrenal incidentalomas. A 45-year-old female with history of diet-controlled diabetes and HTN presented with a two-week history of bilateral upper extremity weakness and paresthesia, along with gait instability. She had reduced motor power in the upper extremities on physical exam. MRI cervical spine demonstrated a cervicothoracic syrinx, cerebellar tonsillar ectopia consistent with CM1. MRI brain showed diffuse enlargement of the pituitary gland measuring 16 x 14 x 13 mm bulging into the suprasellar cistern and minimally abutting the inferior aspect of the optic chiasm. MRI lumbar spine revealed a left adrenal gland nodule measuring 1.5 x 2.0 cm. Endocrine hormonal evaluation showed normal prolactin, follicle stimulating and luteinizing hormone, estradiol, free T3, free T4, and IGF-I levels. Aldosterone level was high in supine position with normal plasma renin activity initially with normal levels on repeat testing. Plasma free metanephrine, normetanephrine, testosterone levels were also normal. Patient was started on dexamethasone in anticipation of surgery. Patient underwent suboccipital craniectomy, C1 laminectomy, coagulation of cerebellar tonsils and expansile duraplasty for CM1. Patient did well postoperatively and dexamethasone was tapered off. Postoperative follow up after patient had been off steroids for three weeks showed normal levels of all pituitary and adrenal hormones, including normal dexamethasone suppression test. While CM1 is a rare finding, pituitary adenomas are relatively common. In cases of concomitant occurrence of CM1 and growth hormone secreting pituitary adenoma, over-secretion of growth hormone has been proposed as a mechanism to precipitate symptoms of CM1 by causing hypertrophy of connective and ligamentous tissue in the skull base and of the cranio-cervical canal. Our patient had normal IGF-1 levels with a nonfunctional pituitary adenoma raising the question whether there is some other underlying mechanism, possibly a genetic predisposition, that contributed to the concomitant occurrence of CM1 with pituitary and adrenal tumors. Whether these tumors become functional in the future remains to be seen.

LBSAT65 Search For A Duplicitous Pheochromocytoma

Abstract Introduction Pheochromocytomas are discovered during work up of adrenal incidentalomas and can be biochemically and clinically silent. We present a case of a patient who presented with typical "adrenergic spells" suggestive of pheochromocytoma but negative biochemical testing and non-confirmatory imaging findings. Case Report 39-year-old male presented with 4 weeks history of episodes of throbbing headaches, palpitations, sweating. He was found to be hypertensive, blood pressure of 220/110 mm Hg. Losartan was initiated, but symptoms persisted. Work-up for endocrine causes of hypertension revealed normal plasma renin activity 1.123 ng/ml/hr (0.167 to 5.380) and undetectable aldosterone level <1 ng/dl (0. 0-3. 0), mildly elevated random plasma normetanephrine 270 pg/ml (0-210), normal plasma metanephrines 49 pg/ml (0-88). Low-dose dexamethasone suppression test showed unsuppressed morning cortisol of 2.1ug/dl, undetectable ACTH <5 pg/ml, dexamethasone level 486 ng/dl. 24 urinary cortisol and 2 midnight salivary cortisol samples failed to confirm the diagnosis. 24-hr urine studies showed mildly elevated 24-hr normetanephrine 735 ug/24 hr (156-729), normal 24-hr metanephrines 197 ug/L (58-276), normal 24 hr epinephrine and dopamine levels. Repeat testing revealed normal plasma metanephrines levels and mildly elevated plasma normetanephrine levels 287 pg/ml (less than twice above the upper limit of normal). Dopamine and Chromogranin A levels were undetectable. Abdominal CT showed 2 cm round soft tissue density 42HU in right adrenal gland. Left adrenal gland contained 3 nodules measuring 11, 15 and 16 mm–all with density <10HU. MRI findings for the 2.2 cm right adrenal nodule was without significant drop in signal intensity on the in and out of phase sequences appearing moderately T2 hyperintense and T1 hypointense. Differential included atypical/fat poor adenoma, pheochromocytoma, or metastasis. On GA 68 Dotatate PET-CT this 2.2cm adrenal nodule had minimal to low radiotracer uptake. Since a pheochromocytoma could not be ruled out, patient was started on alpha blockade. Preoperative genetic testing was negative for common mutations associated with pheochromocytoma/paraganglioma syndromes. Patient underwent laparoscopic right adrenalectomy. Histopathology report confirmed 2.8 cm pheochromocytoma with a low PASS (2/20) and low GAPP score. Conclusion and Discussion Patients with borderline nor metanephrine elevations represent a diagnostic and therapeutic dilemma. The patient presented with adrenergic paroxysms strongly suggestive of underlying pheochromocytoma. Labs and imaging were not typical for pheochromocytoma and were indeterminate. Given strong clinical suspicion for a pheochromocytoma, we decided to proceed with adrenalectomy after pre-treatment with alpha blockers. Final histopathologic report confirmed the diagnosis of pheochromocytoma. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Hypocortisolism in a dog caused by bilateral pheochromocytoma

AbstractWe present a 12‐year‐old French bulldog with muscle weakness, epigastric pain, weight loss, high systolic blood pressure and cardiac arrhythmias. Physical and laboratory examination revealed no abnormalities. On a computed tomography scan, severely enlarged adrenals were found, and endocrine and biochemical evaluations excluded hypercortisolism and hyperaldosteronism. Urinary metanephrine and normetanephrine/creatinine ratios were elevated, compatible with a diagnosis of pheochromocytoma. Symptomatic treatment with phenoxybenzamine was started and resulted in normalisation of a systolic blood pressure and reduction of arrhythmias. However, the onset of anorexia, vomiting and clinical deterioration prompted exploration of the adrenocortical reserve through an adrenocorticotropic hormone stimulation test, which confirmed glucocorticoid deficiency. Mineralocorticoid deficiency was ruled out by normal plasma aldosterone concentration and renin activity. Finally, an elevated endogenous plasma adrenocorticotropic hormone concentration defined the primary origin of the hypocortisolism. Clinical resolution occurred with prednisolone supplementation. This is the first report of hypocortisolism in a dog caused by a bilateral pheochromocytoma.

A case of atypical reninoma with mild hypertension and normal plasma renin activity but elevated plasma renin concentration

BackgroundReninoma is a rare, benign renal neoplasm. Typical clinical features include severe hypertension, secondary hyperaldosteronism, hypokalaemia and metabolic alkalosis caused by the overproduction of renin.Case presentationA 25-year-old lean Chinese woman with no family history of hypertension was hospitalized for stage 1 hypertension that gradually developed over two years. Endocrine investigation showed hyperreninemia without hyperaldosteronism and hypokalaemia. Interestingly, although the patient had an elevated plasma renin concentration (PRC), her plasma renin activity (PRA) was in the normal range. Abdominal contrast-enhanced computed tomography (CT) scanning revealed a solid, low-density, renal cortical mass with delayed enhancement. Selective renal vein sampling (SRVS) was performed, and a lateralization of the renin secretion from the left kidney was found. Enucleation of the tumour led to a rapid remission of hypertension and hyperreninemia. Based on pathological findings, the patient was diagnosed with reninoma. Immunohistochemical staining of the tumour was positive for Renin, CD34, Vimentin, and synaptophysin (Syn) and negative for somatostatin receptor 2 (SSTR2) and chromogranin A (CgA).ConclusionsReninoma can present as mild hypertension without hyperaldosteronism and hypokalaemia. The clinical features of reninoma may depend on the degree of activation of the renin-angiotensin-aldosterone system (RAAS). PRC should be incorporated in the differential diagnosis of secondary hypertension.

Mitotane in the Treatment of Adrenocortical Carcinoma: Metabolic and Endocrine Disruption

Abstract Background: Mitotane is a well-known adrenocytolitic agent resulting in adrenal insufficiency. However, little is known about its multiple and complex metabolic and endocrine effects. Clinical Case: Patient is a 6 year 9 month old female who presented with acne, pubic hair and rapid weight gain. Initial evaluation showed elevated testosterone (64 ng/dL), 17-OH-progesterone (236 ng/dL), DHEA-S (922 mcg/dL), and random cortisol (30.9 mcg/dL) with suppressed ACTH (<2.0 pg/mL). She had an inappropriate lack of suppression after a 1 mg overnight dexamethasone suppression test (cortisol 49 mcg/dL, nl <2 mcg/dL). Abdominal CT showed large necrotic-appearing right adrenal mass (10.7x8.8x15 cm) with no metastasis. Surgical excision was complicated by intraoperative rupture. Pathology confirmed stage III right adrenal cortical carcinoma. Patient was started on etoposide, cisplatin, doxorubicin, and mitotane as adjuvant therapy. 6 days after surgery, her DHEA-S and cortisol levels were undetectable. She was started on glucocorticoid replacement therapy with hydrocortisone at 18 mg/m2/day. Due to severe nausea, she was switched to dexamethasone 5 mg/m2/day (245 mg/m2/day dose equivalent to hydrocortisone). However, the patient developed hypotension, increased nausea and emesis and was switched back to hydrocortisone. The patient’s clinical course was complicated by hyperlipidemia with total cholesterol 215 mg/dL, HDL 48 mg/dL and LDL 150 mg/dL, as well as central hypothyroidism with low FT4 (0.8 ng/dL) and an inappropriately low normal TSH (0.31 mcIU/mL). She was started on levothyroxine with a final dose of 2.6mcg/kg/day to achieve euthyroid state. Mineralocorticoid deficiency has been reported in a small number of case reports of mitotane use. Our patient continues to demonstrate adequate mineralocorticoid function based on her normal electrolytes, aldosterone and plasma renin activity level. Conclusion: Mitotane exerts multiple clinically relevant metabolic and endocrine effects. Patients treated with mitotane should be monitored for complications including mineralocorticoid deficiency, central hypothyroidism, and hyperlipidemia. Dexamethasone must be avoided because of the rapid inactivation by CYP4503A4 leading to adrenal crisis. Typical glucocorticoid replacement dose must be doubled due to induction of CYP3A4 activity that leads to glucocorticoid inactivation.

The effect of the components of the renin-angiotensinaldosterone system on the development of diabetic nephropathy in type 1 diabetes (review)

One of the key roles in the development of diabetic nephropathy belongs to the renin-angiotensin-aldosterone system (RAAS), which is involved in the regulation of hemodynamics, systemic and intrarenal pressure, production of profibrogenic and growth factors, vascular remodeling. At the end of the twentieth century, local (tissue) RAAS elements from renin to aldosterone were found in tissues and target organs (including kidneys). Tissue RAAS plays a leading role in the development of vascular complications of diabetes mellitus (DM): cardiovascular disease, diabetic nephropathy, and retinopathy. It is this fact that explains in many ways the pathogenetic role of RAAS in the defeat of target organs even with normal or low plasma renin activity (ARP). RAAS activation occurs long before the clinical signs of diabetic nephropathy, which makes it possible for earlier prevention and correction of initial changes in the study of its components, as well as reducing disability and the output of patients in chronic kidney disease. Given the tendency to “rejuvenate” diabetes mellitus, the lability of the course of the disease in childhood, the high hormonal activity in this group of patients, and, therefore, the greater the risk of complications, the timely diagnosis of the initial manifestations of DN is of high relevance and relevance.

The renin secretion profile under the influence of sleep deprivation and the neuropeptides CRH and GHRH

It is already known that during normal sleep plasma renin activity (PRA) shows oscillations with decreases during rapid-eye-movement (REM) sleep and increases during non-REM (NREM) sleep. We also know that renin correlates positively with slow-wave sleep (SWS). Sleep deprivation is known to enhance significantly SWS and slow wave activity (SWA, known as δ power).Based on these findings we addressed the question whether and to which extent sleep deprivation may affect the synchronization found between PRA and REM sleep during normal sleep and whether this synchronization is affected by other sleep regulating factors. To investigate these questions we compared sleep EEG and sleep-related free renin levels in 48 normal women and men 19–69 years old between nights before and after 40 h of sleep deprivation. During the recovery night, four bolus injections of either GHRH, CRH or placebo were injected via long catheter around sleep onset. When compared to baseline after each of the treatments SWS, SWA and renin levels increased. The characteristical oscillation profiles of renin during normal sleep were also preserved after sleep deprivation. Similar to normal sleep our data support also a distinct link between nocturnal renin secretion and SWS after sleep deprivation and that independent of the applied treatments.

SUN-170 Adrenal Insufficiency Due to Adrenal Hemorrhage

Introduction: Antiphospholipid Syndrome (APS) can involve multiple organ systems but endocrine manifestations are rare. In most cases adrenal insufficiency (AI) is the first endocrine manifestation of APS. The prompt diagnosis of adrenal insufficiency is critical. We present a case of AI associated with antiphospholipid syndrome who was managed successfully. Case presentation: A 50-year-old man was admitted with deep venous thrombosis of the distal left femoral vein extending to the popliteal vein and was started on xarelto, but he developed pleuritic chest pain and dyspnea in 48 hours. CT scan confirmed a pulmonary embolism and patient was treated with heparin drip. Two days following heparin drip patient developed acute bilateral flank pain and hypotension; and CT abdomen showed 2 masses replacing the adrenal glands that were concerning for hematomas. Laboratory results: serum potassium 4.9 mmol/L, serum cortisol 3.3 mcg/dL (reference 7.2–19.4), ACTH level 319 pg/mL (reference 7–53), aldosterone <1.0 ng/dL (reference 0.0–3.0), and plasma renin activity 7.17 ng/ml/hr (reference, 0.15–3.95). Serum antiphospholipid antibody testing showed cardiolipin Ab Ig 140 GPL/mL (reference 0–14), cardiolipin Ab IgM 100 MPL/mL (reference 0–12) and cardiolipin Ab IgA >150 APL/mL (reference 0–11). Further testing showed beta-2 glycoprotein 1 Ab IgG 103 GPI units (reference 1–20), IgM 94 GPI units (reference 0–32), and IgA 150 GPI units (reference 0–25). His hypotension dramatically improved upon administration of IV hydrocortisone and the abdominal pain resolved in 3 days. Upon discharge he was placed on hydrocortisone and continued warfarin therapy. At a 6-week follow-up visit, patient was asymptomatic. Additional lab tests revealed normal plasma renin activity and aldosterone levels. Two years later an ACTH stimulation test confirmed persistent AI. Basal plasma ACTH level was 230 pg/mL (ref 5–50). Additionally plasma renin activity and serum aldosterone levels indicated no mineralocorticoid deficiency. An adrenal CT scan revealed significant long-term interval decrease in size of bilateral adrenals with hypo-attenuating focus in the right adrenal gland, favored to represent post hemorrhage changes without convincing evidence of underlying neoplasm especially given decrease in size compared to 4-years prior. Presently, patient is doing well on hydrocortisone and warfarin treatment. Conclusion: In all cases of adrenal hemorrhage and infarction with unknown etiology, screening with lupus anticoagulant and anticardiolipin antibodies is imperative. Recognition of this high mortality condition will allow for appropriate screening and confirmatory tests leading to prompt diagnosis and timely management.

SUN-390 A Rare Case of Bilateral Macronodular Adrenal Hyperplasia Discovered Incidentally

Introduction: Asymptomatic adrenal masses are often discovered incidentally while testing for unrelated conditions. A very uncommon finding is thickening and increased nodularity of both adrenal glands, which can lead to the patient being diagnosed with subclinical Cushing's syndrome, Conn's syndrome, or both. Case presentation: A 45-year-old African-American man presented to the hospital with a one-month history of increased abdominal girth, bilateral lower extremity edema and shortness of breath, with progressive epigastric abdominal pain which prompted admission. His medical history was relevant for obesity, coronary artery disease and heart failure with reduced ejection fraction. On examination he had a blood pressure of 152/99 mmHg, was diaphoretic, and complained of constant epigastric pain. Multiple purple and pale striae were visible along his abdomen, and he had pitting edema in both lower extremities. His initial laboratory studies showed a potassium of 2.6 mEq/L. A CT scan of the abdomen was relevant for bilaterally enlarged and tortuous adrenal glands, which the patient had no previous knowledge of. Diuresis greatly improved his edema and shortness of breath. Additional laboratory tests showed persistent hypokalemia, normal plasma renin activity and aldosterone, elevated fasting cortisol, normal metanephrines in 24-hour urine collection, and low ACTH level. A suppression test done by administering dexamethasone 0.5 mg every 6 hours for 2 days, was able to suppress the elevated cortisol levels. He was started on spironolactone, and underwent MRI of the abdomen, which confirmed bilateral multinodular adrenal hyperplasia with no imaging characteristics of pheochromocytoma. The patient was discharged home once his clinical status improved. Laboratory studies done at follow-up appointments showed persistently elevated cortisol, normal aldosterone to renin ratio, normal levels of plasma metanephrines and suppressed levels of ACTH. He was also referred to surgery for eventual bilateral adrenalectomy. Discussion: Primary bilateral macronodular adrenal hyperplasia (BMAH) is a very rare cause of endogenous Cushing's syndrome, representing less than 2% of cases. It is characterized by enlarged adrenal glands containing pigmented nodules that secrete excess cortisol and/or aldosterone (1). BMAH is often an incidental finding in patients with subclinical hyper-cortisolism. A low level of plasma ACTH along with bilaterally enlarged adrenal glands on imaging suggest the diagnosis, and this is confirmed with a dexamethasone suppression test. Accurate detection is important for guiding management, which includes pharmacological therapy and bilateral adrenalectomy. Reference: 1. De Venanzi A, Alencar GA, Bourdeau I, Fragoso MCBV, Lacroix A. Primary bilateral macronodular adrenal hyperplasia. Curr Opin Endocrinol Diabetes Obes. 2014 Jun;21(3):177-84.

Diagnostic Role of Renal Doppler Ultrasound and Plasma Renin Activity as Screening Tools for Renovascular Hypertension in Children.

The diagnostic role of an ultrasound (US) and plasma renin activity (PRA) combination is unknown, despite the usefulness of Doppler US as a screening tool for renovascular hypertension (RVHT). The purpose of this study was to evaluate the diagnostic usefulness of US for RVHT in children stratified according to PRA. We identified 336 children who underwent renal Doppler US examinations for hypertension and divided them into a high-renin group (n = 177) and a normal-renin group (n = 159) based on PRA and stratified them by age. The Doppler US findings were retrospectively reviewed, and computed tomographic angiography (CTA) for the same children was used as the reference standard. In the high-renin group, 36 patients had positive Doppler US findings that were confirmed by CTA in 32 cases. The sensitivity and specificity values for Doppler US in the high-renin group were 84.2% and 93.6%, respectively. In the normal-renin group, 10 patients had positive Doppler US findings; these positive findings were confirmed by CTA in 9 cases. The sensitivity and specificity values for US in the normal-renin group were 100.0% and 100.0%. There were anatomic variations (n = 3) and segmental artery stenosis (n = 2) among the cases with false-negative US findings, which were confirmed by CTA. If patients have high PRA, a Doppler US examination should be performed with caution to avoid false-negative detection. If patients have normal PRA, renal Doppler US might be adequate for diagnosis of RVHT to avoid unnecessary CTA.

Striatin Gene Polymorphic Variants Are Associated With Salt Sensitive Blood Pressure in Normotensives and Hypertensives

Understanding the interactions between genetics, sodium (Na+) intake, and blood pressure (BP) will help overcome the lack of individual specificity in our current treatment of hypertension. This study had 3 goals: expand on the relationship between striatin gene (STRN) status and salt-sensitivity of BP (SSBP); evaluate the status of Na+ and volume regulating systems by striatin risk allele status; evaluate potential SSBP mechanisms. We assessed the relationship between STRN status in humans (HyperPATH cohort) and SSBP and on volume regulated systems in humans and a striatin knockout mouse (STRN+/-). The previously identified association between a striatin risk allele and systolic SSBP was demonstrated in a new cohort (P = 0.01). The STRN-SSBP association was significant for the combined cohort (P = 0.003; β = +5.35 mm Hg systolic BP/risk allele) and in the following subgroups: normotensives, hypertensives, men, and older subjects. Additionally, we observed a lower epinephrine level in risk allele carriers (P = 0.014) and decreased adrenal medulla phenylethanolamine N-methyltransferase (PNMT) in STRN+/- mice. No significant associations were observed with other volume regulated systems. These results support the association between a variant of striatin and SSBP and extend the findings to normotensive individuals and other subsets. In contrast to most salt-sensitive hypertensives, striatin-associated SSBP is associated with normal plasma renin activity and reduced epinephrine levels. These data provide clues to the underlying cause and a potential pathway to achieve, specific, personalized treatment, and prevention.

The Importance of Exclusion of Obstructive Sleep Apnea During Screening for Adrenal Adenoma and Diagnosis of Pheochromocytoma.

Context. As catecholamine elevation is a key element in the diagnosis of pheochromocytoma, more commonplace causes of sympathetic excess, such as obstructive sleep apnea (OSA), should be excluded as standard practice prior to diagnosis. This is essential to avoid misdiagnosis of adrenal incidentalomas identified in the estimated 42 million Americans with OSA, with greater than 4 million projected to undergo a computed tomography study annually. Case Description. A 56-year-old woman presented with a several year history of paroxysmal hypertension, palpitations, and diaphoresis. Abdominal/pelvic computed tomography performed during an unrelated hospitalization revealed a 2-cm left-sided adrenal nodule initially quantified at 37 Hounsfield units. Posthospitalization, 24-hour urine normetanephrine level was markedly elevated. Reassessment 2 weeks later revealed continued normetanephrine excess. Following normal thyroid function tests, morning cortisol, aldosterone, and plasma renin activity, laparoscopic adrenalectomy was performed. Surgical pathology identified an adrenal cortical adenoma. As paroxysms continued postoperatively, repeat 24-hour urine metanephrines were measured, demonstrating essentially unchanged normetanephrine elevation. Search for an alternate cause ensued, revealing OSA with progressive continuous positive airway pressure noncompliance over the preceding year. Regular continuous positive airway pressure therapy was resumed, and at the end of 7 weeks, 24-hour urine normetanephrine levels had declined. Conclusion. Pheochromocytomas are rare and sleep apnea is common. However, the overlap of clinical symptoms between these disorders is substantial, as is their ability to produce catecholamine excess. Thus, excluding uncontrolled or undiagnosed OSA in high-risk patients should be standard practice before diagnosing pheochromocytoma.

Impaired aldosterone response to the saline infusion test in patients with resistant hypertension and obstructive sleep apnea

Background In this cross-sectional study, we sought associations among severity of obstructive sleep apnea (OSA), renin-angiotensin-aldosterone system and blood pressure patterns in patients with resistant hypertension. Material and methods In 65 patients with resistant hypertension we measured the apnea-hypopnea index (AHI) by a portable sleep recorded system and aldosterone and plasma renin activity (PRA) in response to saline infusion test. We also collected data on cardiovascular events, dyslipidemia, chronic kidney disease, and diabetes and performed 24-hour blood pressure monitoring (ABPM). Results Baseline PRA, aldosterone and aldosterone-to-renin ratio were within normal range but aldosterone level in response to saline infusion was increased above normal upper limit. In ABPM, 68% of patients had an altered pattern of blood pressure (non-dipping or reverse dipping). AHI was inversely correlated with PRA and positively with weight, BMI, plasma aldosterone, aldosterone to renin ratio, and aldosterone after saline load but not with blood pressure. Patients with severe OSA (AHI > 30) in comparison to those with mild OSA (AHI 5–15) had significantly higher PRA and aldosterone (baseline and after saline load) but comparable values of blood pressure. We did not find significant impact of OSA severity on the frequency of abnormal blood pressure patterns. Frequencies of diabetes, abnormal lipid profiles, ischemic heart disease, myocardial infarction, and stroke increased with increases in severity of OSA. Conclusions Despite of normal basal PRA and aldosterone concentration, patients with resistant hypertension and OSA had impaired response to saline load and a rate of this impairment depended on the severity of OSA.

CHARACTERISTICS OF RENIN PROFILE AND PARAMETERS OF ARTERIAL STIFFNESS IN PATIENTS WITH PREVIOUSLY UNTREATED HYPERTENSION

Aim. To study the characteristics of renin profile and parameters of central pulse wave and arterial stiffness in patients with previously untreated arterial hypertension (HT). Material and methods. Patients (n=83; 39 males (47%); age 57.3±7.6 years) with untreated uncomplicated 1-2 degree HT without associated clinical conditions and diabetes, with glomerular filtration rate>60 ml/min/1.73m2 were enrolled into the study. Plasma renin activity (PRA), plasma renin level and angiotensin II level were evaluated. The analysis of the central pulse wave, and pulse wave velocity (PWV) measurements were performed. Results. The incidence of volume-dependent HT (PRA <0.65 ng/mL/h) was 69%, and the renin-dependent HT with normal PRA (0.65-6.5 ng/ml/h) – 31% in patients with untreated uncomplicated HT. Patients with low PRA are characterized by older age, higher systolic blood pressure (BP) and higher arterial stiffness (increased PWV, increment pressure, augmentation index with a decrease in pulse pressure amplification) after adjustment for these factors. Conclusion. The presence of volume-dependent HT is associated with older age, higher level of systolic BP and increase in arterial stiffness independent of age and BP.

The renin–aldosterone axis in kidney transplant recipients and its association with allograft function and structure

The level of the renin-angiotensin-aldosterone system (RAAS) activity in kidney transplant recipients has not been extensively studied or serially profiled. To describe this axis and to determine its association with GFR change, interstitial expansion and end-stage renal disease (ESRD) we measured plasma renin activity (PRA) and plasma aldosterone levels annually for 5 years in 153 kidney transplant recipients randomly assigned to losartan or placebo. PRA and plasma aldosterone levels were in the normal range at all times and did not vary by immunosuppression regimen. Those on losartan exhibited higher PRA but similar plasma aldosterone levels. Neither baseline nor serial PRA or plasma aldosterone levels were associated with GFR decline, proteinuria or interstitial expansion. Losartan use, [HR 0.48 (95% CI 0.21–1.0), insignificant], and Caucasian donor, [HR 0.18 (95% CI 0.07–0.4), significant] were associated with less doubling of serum creatinine, death or ESRD. Hypertension, less than 3 HLA-matches, the combination of tacrolimus-rapamycin and acute rejection were associated with more events. Neither PRA nor plasma aldosterone levels were independently associated with this outcome. Higher serial plasma aldosterone levels were associated, however, with a significantly higher risk of ESRD, [HR 1.01 (95% CI 1.00–1.02)]. Thus, systemic RAAS is not overly activated in kidney transplant recipients but this may not reflect the intrarenal system. Importantly, plasma aldosterone levels may be associated with more ESRD.

Synergic effect of high renin and aldosterone levels on inappropriate left ventricular mass and systolic function: A tissue Doppler study

Left ventricular dysfunction (LVD) is a harmful condition leading to increased cardiovascular morbidity and mortality. Among the complex pathophysiological factors contributing to the development of LVD, the renin–angiotensin–aldosterone system (RAAS) has been recognized to play a pivotal role. Hyperactivation of RAAS promotes structural and functional changes leading to myocardial fibrosis, stiffness and left ventricular hypertrophy [1–4]. A large proportion of patients with altered RAAS homeostasis presents with isolated increase in plasma renin activity (PRA) or aldosterone concentrations (PAC). However, data about the impact of isolated hyperreninemia or hyperaldosteronism on LV geometry and function are not exhaustive. Moreover, it remains unclearwhether the coexistence of high renin and aldosterone has a synergic effect on cardiac damage. LV mass (LVM) exceeding compensatory values for individual cardiac load has been recently described as inappropriate left ventricular mass (ILVM). This adverse phenotype of cardiac hypertrophy is emerging as a key determinant of cardiovascular risk [5]. In the present study we investigated the individual contribution of isolated PRA and PAC elevations on ILVM and LVD. PRA and PAC were measured in 133 young newly diagnosed hypertensive subjectswho had never been treatedwith RAAS blockers or other antihypertensive drugs. The study population was stratified as follows: 1) normal PRA and PAC (N) [n = 45]; 2) high PRA and normal PAC (hyperreninemia, HR)

Inadequate RAAS suppression is associated with excessive left ventricular mass and systo-diastolic dysfunction

Inadequate suppression of renin-angiotensin-aldosterone system (RAAS) following postural maneuvers may have detrimental effects on cardiac structure and function. In this study, we aimed to appraise the clinical significance of this phenomenon by assessing its relation with inappropriate ventricular mass (ILVM), an adverse phenotype of LV remodeling and dysfunction. Both supine and upright plasma renin activity (PRA) and aldosterone concentrations (PAC) were measured in 115 young newly diagnosed hypertensive subjects. 24-h ambulatory blood pressure monitoring and echocardiographic evaluation including tissue Doppler imaging (TDI) were also performed. Patients were divided as follows: (1) normal PRA and PAC (N) (n = 63); (2) suppressible RAAS (SR) in supine position (n = 27); (3) not suppressible RAAS (NSR) (n = 25). ILVM was expressed as the observed/predicted LV mass ratio ×100 (%PLVM), while LV dysfunction (LVD) was identified by TDI-derived myocardial performance index (MPI). NSR showed a higher prevalence of ILVM than SR and N. As compared with N and SR, NSR patients had reduced indices of systolic and diastolic function. MPI of the LV as well as prevalence of LVD was also significantly higher in the NSR group. Regression models showed that lack of RAAS suppression was independently associated with ILVM and LVD. Prevalence of ILVM and LVD is higher in patients without clinostatic RAAS suppression. Our findings encourage the assessment of RAAS deregulation to better estimate individual cardiovascular risk in patients with arterial hypertension.

A Clinical Link Between Peroxisome Proliferator-Activated Receptor γ and the Renin–Angiotensin System

A mechanistic link between peroxisome proliferator-activated receptor γ (PPARγ) and the renin–angiotensin system (RAS) has been previously proposed, but clinical evidence supporting the relationship is incomplete. In the current issue of Arteriosclerosis, Thrombosis, and Vascular Biology , Caron-Debarle et al show that 4 patients with familial partial lipodystrophy associated with early-onset severe hypertension carry mutations in PPARγ that impair its ability to act as a ligand-activated transcription factor. Cells isolated from these patients, and cells transfected with the same mutations in PPARγ, exhibit activation of the cellular RAS, increased production of reactive oxygen species (ROS), and markers of inflammation, all of which are dependent on the angiotensin-II (Ang-II) AT1 receptor (AT1R). This translational study further supports a role for PPARγ as a regulator of blood pressure through its ability to modulate the RAS. See accompanying article on page 829 PPARγ is a ligand-activated transcription factor and target of the thiazolidinedione (TZD) class of antidiabetes mellitus medications. PPARγ is best recognized for its role in adipogenesis, but is also a regulator of systemic metabolism as evidenced by the pleiotropic abnormalities (lipodystrophy, insulin-resistance, and metabolic syndrome) caused by PPARγ mutations.1–3 Clinical studies of TZD use in type 2 diabetes mellitus, including the PROactive (PROspective pioglitAzone Clinical Trial In macroVascular Events) trial, documented improved endothelial function and modest, but significant reductions in blood pressure.4 Some of the same mutations that cause lipodystrophy and diabetes mellitus also cause severe hypertension and preeclampsia in human patients3 and in knock-in mice.5,6 Evidence suggests that PPARγ activity in the vascular endothelium and smooth muscle are important regulators of endothelial function, smooth muscle contraction, and systemic blood pressure.7,8 Data suggesting a role for PPARγ in regulating blood pressure led many to search for downstream …