Expression of vasopressin receptors in ACTH-independent macronodular bilateral adrenal hyperplasia causing Cushing's syndrome: molecular, immunohistochemical and pharmacological correlates

Cortisol secretion in ACTH-independent macronodular adrenal hyperplasia (AIMAH) causing Cushing's syndrome can be controlled by illegitimate receptors. The aim of the present study was to characterize the molecular, immunohistochemical, and pharmacological profiles of vasopressin receptors in cells derived from three patients with AIMAH (H1-H3), in order to evaluate the role of ectopic vasopressin receptors in the physiopathology of hypercortisolism. Expression of mRNAs encoding the vasopressin receptor types (V(1a), V(1b), and V(2)) were analyzed by RT-PCR in adrenal tissues. The presence of V(1a) and V(2) receptors was studied by immunohistochemistry on adrenal sections. The pharmacological profiles of vasopressin receptors involved in the control of cortisol secretion were investigated using the V(1a) receptor antagonist SR49059 and the V(2) receptor agonist [deamino-Cys(1), Val(4), D-Arg(8)]-vasopressin on cultured cells. The V(1a) receptor protein was present and functional in H1 and H3 tissues, whereas the V(1b) receptor was not expressed in any of the tissues. RT-PCR experiments revealed that V(2) receptor mRNAs were detected in the three tissues. In contrast, immunohistochemical and cell incubation studies showed that the V(2) receptor was involved in the stimulatory effect of AVP on cortisol secretion in H1 and H2, but not in H3 cells. Taken together, these data show that expression of functional ectopic V(2) receptors and repression of eutopic V(1a) receptor can coexist in some hyperplastic corticosteroidogenic tissues. They also reveal that immunohistochemical and incubation studies are essential for the characterization of ectopic receptors actually involved in the control of cortisol secretion by AIMAHs.     

12例ACTH非依赖性肾上腺皮质大结节样增生的诊治

目的 探讨ACTH非依赖性肾上腺皮质大结节样增生(AIMAH)的诊断与治疗.方法 回顾性分析12例AIMAH患者的临床表现、内分泌检查、影像与病理特点以及治疗和预后.男性5例,女性7例,平均年龄48岁(29～66岁).结果 7例有典型库欣综合征表现,5例则仅有高血压或高血糖等非特异性症状.内分泌检查显示皮质醇分泌失去昼夜节律,大、小剂量地塞米松抑制试验均不被抑制.CT或MRI示双肾上腺弥漫性增大伴多发结节.11例行手术治疗,其中双侧肾上腺切除3例;一侧肾上腺全切,对侧肾上腺次全切除1例;单侧肾上腺切除7例.病理诊断肾上腺结节样或腺瘤样增生.随访14～124个月,库欣综合征症状消失.双侧肾上腺切除者无Nelson综合征出现,单侧肾上腺切除者血尿皮质醇在正常范围,对侧肾上腺无明显增大.结论 AIMAH有独特的临床病理特点,单侧肾上腺切除是一种安全、有效的治疗选择.对症状不缓解或复发者可行双侧肾上腺切除或一侧肾上腺全切、对侧肾上腺次全切除.

Abstract：

Objective To explore the diagnosis and treatment of adrenocorticotropin-independent macronodular adrenal hyperplasia (AIMAH). Methods The clinical symptoms, endocrinological and radiological characteristics, treatment modalities, and postoperative clinical course of 12 AIMAH patients were retrospectively reviewed. There were 5 men and 7 women with an average age of 48 years old. Results All cases had some clinical features and biochemical evidence of Cushing's syndrome. The circadian rhythm of serum cortisol was abnormal. Low- and high-dose dexamethasone suppression tests failed to suppress cortisol secretion. CT or MRI scan showed bilateral enlargement of the adrenal glands with multiple macronodules. Bilateral adrenalectomy was performed in three patients and unilateral adrenalectomy combined with contralateral subtotal adrenalectomy was performed in one patient. Seven patients underwent unilateral adrenalectomy of the larger gland. The removed adrenal glands weighted within 8-96 g range and pathologic diagnoses were nodular or adenomatoid hyperplasia of adrenal cortex. The duration of postoperative follow-up was 14 to 124 months. Clinical symptoms of Cushing's syndrome disappeared after surgery in all cases and there was no Nelson's syndrome after bilateral adrenalectomy. Urinary free cortisol and serum cortisol were within normal ranges. No further enlargement of the contralateral gland has been noticed in patients who received unilateral adrenalectomy during the follow-up.Conclusions AIMAH had unique endocrinological and pathological features. Unilateral adrenalectomy appears to be an effective and safe alternative treatment for AIMAH. Bilateral adrenalectomy or unilateral adrenalectomy combined with contralateral subtotal adrenalectomy may be performed if the symptoms had not been improved or recurred after unilateral adrenalectomy.     

非ACTH依赖性双侧肾上腺大结节增生患者的临床特点分析

目的 探讨非ACTH依赖性双侧肾上腺大结节增生(AIMAH)患者的临床特点.方法 回顾性分析1998年至2010年解放军总医院内分泌科收治并确诊的18例非ACTH依赖性双侧肾上腺大结节增生患者的临床资料.结果 (1) AIMAH患者男女比例1∶1,平均就诊年龄(51.4±10.7)岁,平均病程(9.9±2.7)年;(2)部分患者因体检意外发现肾上腺占位就诊;高血压、糖代谢异常最常见,满月脸、向心性肥胖等典型的库欣综合征(CS)体征较少见;(3)实验室检查示患者均为非ACTH依赖性CS,部分患者具备亚临床CS的特点;24 h动态血ACTH、皮质醇水平监测能全面、清晰显示部分AIMAH患者亚临床库欣综合征的特点;外源性ACTH能刺激皮质醇的显著分泌;(4)CT显示双侧肾上腺结节样增生改变,结节直径多在1.0～3.5cm;(5)病理显示肾上腺组织结节样增生;(6)双侧肾上腺切除治疗效果较好,单侧切除效果不佳.结论 AIMAH为库欣综合征的独立少见类型,部分患者表现为亚临床库欣综合征,非ACTH依赖性及双侧肾上腺结节样增生为该病最重要的临床特点.     

A case of ACTH-independent macronodular adrenal hyperplasia associated with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant neoplasia syndrome characterized by the occurrence of tumors in the parathyroid glands, pancreas, and anterior pituitary. Approximately 30-40% of MEN1 patients also have adrenal lesions, such as hyperplasia, benign adenoma, and adrenocortical carcinoma. Most of the cases are hormonally silent. We describe the case of a 60-year-old man with bilateral macronodular adrenal lesions, in addition to parathyroid tumors, multiple insulinomas, and non-functioning pituitary microadenoma. Endocrinological tests revealed subclinical hypercortisolism; midnight cortisol level rose slightly (8.0 μg/dL), although basal plasma ACTH and cortisol levels were within the normal range (19.5 pg/mL and 12.0 μg/dL, respectively). One and 8 mg dexamethasone suppression tests showed cortisol levels of 2.3 and 9.8 μg/dL, respectively. (131)I-adosterol scintigraphy under dexamethasone suppression revealed bilateral adrenal uptake with right-sided predominance. The histological features of the removed right adrenal gland were consistent with ACTH-independent macronodular adrenal hyperplasia (AIMAH): immunoreactivity of 17α-hydroxylase was predominantly observed in the small compact cells, while that of 3β-hydroxysteroid dehydrogenase was exclusively expressed in the large clear cells. The glucose-dependent insulinotropic polypeptide (GIP) receptor was expressed at high levels in compact cells, suggesting that GIP is responsible for the development of AIMAH. Unilateral small adrenal lesions were detected in the patient's 2 children, who also presented with MEN1 symptoms. Genetic abnormalities in the MEN1, p27, and p18 genes were not found, however, the present case may provide a clue to the understanding of the etiology of MEN1 and AIMAH.     

A case of ACTH-independent bilateral macronodular adrenal hyperplasia successfully treated by subtotal resection of the adrenal glands: four-year follow-up

We report ACTH-independent bilateral macronodular adrenal hyperplasia (AIMAH) seen in a 48-year-old male with a history of rectal and skin cancer. Bilateral multiple adrenal nodular lesions on abdominal CT scans, elevated early morning plasma cortisol levels with undetectable plasma ACTH, increased 24-hour urinary free cortisol excretion, and loss of the normal circadian rhythm in cortisol secretion established the diagnosis of AIMAH. Subtotal resection of the adrenal glands preserving lower one third of the left side was performed, considering the unfavorable effects of total adrenalectomy on future treatment of his malignancies. He has been doing well for four years with normal plasma ACTH and cortisol levels. This case suggests that subtotal resection of the adrenal glands may be applicable to selected patients.     

A case of severe hypertension caused by ACTH-independent macronodular adrenal hyperplasia

This report describes a rare case of ACTH-independent macronodular adrenal hyperplasia (AIMAH) arisen with symptomatic severe hypertension and hypokaliemia. A 55-year-old man was admitted to hospital with a clinical picture characterized by several episodes of transient ischemic attacks (TIA) and right hemiplegia, related to severe arterial hypertension. Laboratory tests showed urinary levels of catecholamines, metanephrines and vanillylmandelic acid (VMA) in normal range; high urinary free cortisol excretion, elevated serum cortisol with loss of the circadian rhythm and low ACTH plasma levels. ACTH failed to respond to CRH administration. Serum cortisol levels were not modified after high doses of dexamethasone. MRI showed bilateral macronodular hyperplasia of adrenal glands, whereas pituitary-MRI did not show tumoral lesions. Therefore, ACTH-independent macronodular hyperplasia was suspected. Though obese, the patient had no typical Cushing habit, and symptomatic hypertension with hypokaliemia was the only clinical evidence for this rare kind of Cushing's syndrome. After obtaining a satisfactory control of blood pressure, the patient was successfully submitted to laparoscopic bilateral adrenalectomy and underwent complete clinical remission. The histology showed adrenal macronodular hyperplasia. During the twenty-four month follow-up, the patient had no further transient ischemic attacks or need of glucocorticoid replacement therapy and withdrew the antihypertensive drugs.     

A case of ACTH-independent bilateral macronodular adrenal hyperplasia and severe congestive heart failure

Cortisol secretion in ACTH independent bilateral macronodular adrenal hyperplasia (AIMAH) can be regulated by aberrant adrenal receptors. We describe a patient with Cushing's syndrome (CS) due to AIMAH and concomitant Class IV congestive heart failure (CHF). Clinical testing for the presence of aberrant receptors revealed a pronounced serum cortisol (257%) and aldosterone response (212%) to the administration of ACTH and a partial serum cortisol (35%) and aldosterone (106%) response to upright posture. This suggested the possible presence of aberrant hormone receptors for ACTH [melanocortin 2 receptor (MC2-R)], vasopressin, catecholamines or angiotensin II (AT-II) on the patient's adrenal glands. Adrenal tissue from the patient demonstrated an eight-fold increased expression of MC2-R compared to normal adrenal tissue. This increased expression was consistent with the increase in cortisol and aldosterone seen in response to exogenous ACTH. We propose that the severe CHF resulted in activation of the renin-angiotensin system, with an increased production of AT-II. The elevated circulating levels of AT-II may have led to increased expression of MC2-R on the patient's adrenal glands and increased responsiveness to ACTH. This unusual case of CS may elucidate a heretofore unknown mechanism for the development of AIMAH.     

A rare case of ACTH-independent macronodular adrenal hyperplasia associated with aldosterone-producing adenoma

A 52-year-old man was evaluated for incidentally discovered bilateral adrenal masses. He had drug-resistant hypertension but lacked Cushingoid features. Endocrinological tests revealed autonomous secretion of cortisol and aldosterone with suppressed plasma ACTH and renin activity. A selective adrenal venous sampling demonstrated aldosterone hypersecretion from the left adrenal vein. The clinical diagnosis of subclinical Cushing's syndrome due to ACTH-independent macronodular adrenal hyperplasia (AIMAH) associated with primary aldosteronism was made, and he underwent left adrenalectomy; the resected adrenal lesion was consistent with the pathological diagnosis of AIMAH coexistent with aldosterone-producing adenoma (APA). This is a very rare case of AIMAH with concomitant unilateral APA, whose hypertension improved after surgery.     

Eutopic overexpression of vasopressin v1a receptor in adrenocorticotropin-independent macronodular adrenal hyperplasia

Arginine vasopressin (AVP) stimulates cortisol secretion through its vascular type V(1a) receptor in the adrenal glands, in addition to stimulating ACTH secretion through pituitary V(3) receptor. Because hyper-response of plasma cortisol to vasopressin is documented in some patients with Cushing's syndrome due to adrenal adenoma (CS) or ACTH-independent macronodular adrenocortical hyperplasia (AIMAH), we analyzed the expression of V(1a), V(2), V(3) receptor and AVP mRNA in human adrenal tissues by quantitative competitive RT-PCR or real-time PCRs. V(1a) receptor mRNA levels (ratio against glyceraldehyde 3-phosphate dehydrogenase) were 0.378 +/- 0.143 (mean +/- SE) in preclinical CS (n = 5) and 0.630 +/- 0.072 in AIMAH (n = 4), which were significantly higher than those (0.046 +/- 0.012; n = 9) in control adrenals, whereas those in overt CS (0.143 +/- 0.048; n = 10) or aldosterone-producing adenomas (0.069 +/- 0.018; n = 12) were similar to control adrenals. Although ectopic expression of V(2) or V(3) receptor was detected in half of AIMAH cases, the absolute levels were low. Furthermore, V(1a) receptor mRNA levels in the adjacent adrenal glands (0.190 +/- 0.039, n = 9) of aldosterone-producing adenomas were higher than those in control adrenals and in the corresponding tumor portions (0.079 +/- 0.024). In contrast, there were no significant differences in AVP mRNA levels among these groups. These results suggest that eutopic V(1a) receptor overexpression is involved in the etiology of AIMAH and a subset of adrenal adenomas causing overt or preclinical Cushing's syndrome. Our results imply a possible association of V(1a) receptor expression with adrenal hyperplasia.     

高危ACTH非依赖性肾上腺皮质大结节样增生的围手术期处理(附一例报告)

目的 提高促肾上腺皮质激素(ACTH)非依赖性肾上腺皮质大结节样增生(AIMAH)的治疗水平.方法 报告了1例AIMAH患者的诊治经过.患者女性,51岁,发现库欣症状半年余,血皮质醇以及24 h尿游离皮质醇升高,血皮质醇昼夜分泌节律消失,2 mg和8 mg地塞米松抑制试验均不被抑制,心肺功能极差,血压最高至300/120 mm Hg(1 mm Hg=0.133 kPa).起始服用米托坦(60 mg/d),效果不佳,后改用酮康唑( 800 mg/d).5天后血压降至180/120 mm Hg,但心、肺功能改善仍不明显,出现端坐呼吸,氧饱和度一度跌至75％,只能尽快行右肾上腺全切术.结果 切除的肿块约10 cm×10 cm大小,称重67.5g.病理示肾上腺非色素性大结节样增生.术后未补充肾上腺皮质激素,术后第6天起继续使用酮康唑( 400 ～ 800mg/d)降皮质醇,血、尿皮质醇逐渐正常(血皮质醇8:00时18.65 μg/dl,24 h尿游离皮质醇78.75 μmol),一般情况好转后出院.随访10个月至今,实验室检查指标正常.结论 AIMAH患者拟采用个体化治疗,对于症状进展迅速,血压极高,心脏受累,低血钾,低蛋白血症者,先通过药物抑制肾上腺分泌糖皮质激素.一旦心肺功能有改善,应尽快切除一侧肾上腺.围手术期不宜补充肾上腺皮质激素.单侧肾上腺全切术依然是一种治疗高危AIMAH有效的方法.     

Unilateral adrenalectomy improves insulin resistance and diabetes mellitus in a patient with ACTH-independent macronodular adrenal hyperplasia

ACTH-independent macronodular adrenal hyperplasia (AIMAH) is a rare cause of Cushing's syndrome. Bilateral adrenalectomy is considered to be a standard therapy for AIMAH, although lifetime replacement of glucocorticoids is necessary after the procedure. This paper describes a subject with AIMAH who underwent unilateral adrenalectomy of the predominantly enlarged gland and subsequently displayed an improvement in insulin resistance and diabetes mellitus, the cardinal symptoms before the operation, concomitant with alleviation of abnormal cortisol secretion. The patient was a 61-year-old man with a body mass index of 25.6 kg/m2. He was diagnosed as having diabetes mellitus, hypertension, and hyperlipidemia at 50 years of age. Eight years after diagnosis, bilateral enlargement of the adrenal glands was revealed by chance upon computed tomography of the abdomen. Typical manifestations of Cushing's syndrome were not demonstrated. Basal levels of serum and urinary cortisol had not increased, although the serum cortisol level displayed no circadian rhythm and no response to the administration of dexamethasone. Despite sulfonylurea treatment, the patient's HbA1C level was as high as 7.6% (normal range 4.3-5.8%). Fasting insulin concentration was increased to 42.6 microU/ml, and the homeostasis model insulin resistance index (HOMA-R) was calculated to be 15.5 (with a normal range of less than 2.5), indicating severe insulin resistance. Unilateral adrenalectomy of the predominantly enlarged gland revealed that the resected gland consisted of multiple nodules of various sizes. Based on endocrinological, radiological, and pathological findings, a diagnosis of AIMAH was made. Ten months after the unilateral adrenalectomy, cortisol circadian rhythms were restored, and serum cortisol concentration was suppressed in response to the administration of low doses of dexamethasone, suggesting an improvement in the cortisol secretory pattern. Levels of HbA1C, fasting insulin, and HOMA-R decreased to 5.7%, 12.7 microU/ml, and 2.2, respectively. An improvement in hyperlipidemia was also observed. Insulin resistance and glucose intolerance are recognized as features of mild hypercortisolism. In the present case, unilateral adrenalectomy was effective in ameliorating insulin resistance and improving glycemic control. Unilateral adrenalectomy might be an alternative therapy for improvement of glucose and lipid metabolism in subjects with AIMAH.     

Familial vasopressin-sensitive ACTH-independent macronodular adrenal hyperplasia (VPs-AIMAH): clinical studies of three kindreds

Objective  Cushing's syndrome due to familial ACTH-independent macronodular adrenal hyperplasia (AIMAH) has been reported in small kindreds. In vasopressin-sensitive AIMAH (VPs-AIMAH), VP stimulates an aberrant, ACTH-independent increase in cortisol. The aims of this study were to (i) delineate the preclinical phenotype of VPs-AIMAH in a three-generation kindred (AIMAH-01) and two smaller kindreds (AIMAH-02 and AIMAH-03) and (ii) investigate the aetiology of VP sensitivity in AIMAH-01.
Design  Clinical studies of three kindreds for adrenal tumours or early Cushing's and molecular studies of adrenal tumours (AIMAH-01).
Patients  Thirty-three individuals, from three kindreds, were screened for perturbations of the hypothalamic–pituitary–adrenal axis or adrenal tumours.
Measurements  Patients underwent clinical, biochemical and adrenal imaging investigations. Evaluation included low-dose (1 IU/70 kg) VP stimulation. Adrenal VP receptor (AVPR1A, AVPR1B, AVPR2) expression (AIMAH-01) was assessed using RT-PCR and immunohistochemistry (IHC). IHC for VP was also performed.
Results  AIMAH-01 had three siblings with Cushing's, and four individuals with suppressed ACTH/aberrant VP responses and/or adrenal nodules. In AIMAH-02, a father and son were affected. AIMAH-03 had three siblings with Cushing's.
RT-PCR showed adrenal overexpression of AVPR1A and AVPR1B. IHC detected AVPR1A. The adrenal tumour from one patient also stained weakly for VP and AVPR2.
Conclusion  Adrenal nodules, suppressed ACTH and increased VP sensitivity may represent preclinical disease, allowing early detection, and treatment, of affected individuals. In AIMAH-01, increased VP sensitivity may be due to adrenal VP receptor overexpression. In these kindreds, VPs-AIMAH is familial, and autosomal dominant inheritance is most likely.     

Adrenocorticotrophin-independent macronodular adrenal hyperplasia in a patient with lysine vasopressin responsiveness but insensitivity to gastric inhibitory polypeptide

The aetiology of ACTH-independent macronodular adrenal hyperplasia (AIMAH) is uncertain. We examined a 55 year old man with Cushing's syndrome due to AIMAH, whose cortisol levels increased after stimulation with lysine-8-vasopressin (LVP) in vitro as well as in vivo . Abdominal MRI revealed nodular enlargement of both adrenal glands. No adenoma was evident on pituitary MRI. ¹³¹I-adosterol scintigraphy exhibited marked uptake into both adrenal glands. Although baseline plasma cortisol levels were within normal limits, urinary free cortisol excretion was 3-fold higher than the upper limit of the normal range. Plasma ACTH levels were undetectable. Oral dexamethasone failed to suppress plasma cortisol levels irrespective of dose, and administration of corticotrophin releasing hormone failed to increase plasma ACTH and cortisol levels. LVP injection failed to increase plasma ACTH levels, but elicited an increase in plasma cortisol levels. The direct stimulatory effect of LVP on cortisol secretion was confirmed in vitro in cultured adrenocortical cells from macronodules obtained at surgery. Food intake, gastric inhibitory polypeptide (GIP), or octreotide administration, which were reported to regulate cortisol release in patients with AIMAH, failed to affect plasma cortisol levels. In conclusion, plasma cortisol responsiveness to LVP, GIP, and octreotide is heterogeneous in patients with AIMAH.