Clinical identification of expressed proteins in adrenal medullary hyperplasia detected with hypertension

BACKGROUND

Hypertension remains a challenging public health problem worldwide, and adrenal gland-related diseases are one class of the major causes for secondary hypertension. Among them, one relatively rare pattern is adrenal hyperplastic hypertension caused by adrenal medullary hyperplasia (AMH), leading to excessive secretion of autonomic catecholamine. Given that the pathological changes of adrenal medulla are not well correlated to the onset and even severity of secondary hypertension, the molecular basis why some AMH patients are accompanied with hypertension remains unclear and is worth exploring.

AIMS

For this reason, this study aims at investigating differentially expressed proteins in clinical AMH tissue, with special focus on the potential contribution of these differentially expressed proteins to AMH development, in order to have a better understanding of mechanisms how AMH leads to secondary hypertension to some extent.

METHODS AND RESULTS

To this end, AMH specimens were successfully obtained and verified through computed tomography (CT) and haematoxylin-eosin (HE) staining. Proteomic analyses of AMH and control tissues revealed 782 kinds of differentially expressed proteins. Compared with the control tissue, there were 357 types of upregulated proteins and 425 types of downregulated proteins detected in AMH tissue. Of interest, these differentially expressed proteins were significantly enriched in 60 gene ontology terms (P < 0.05), including 28 biological process terms, 14 molecular function terms, and 18 cellular component terms. Pathway analysis further indicated that 306 proteins exert their functions in at least one Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Western blotting showed enhanced expression of phenylethanolamine N- methyltransferase (PNMT), myelin protein zero (MPZ), and Ras-related protein Rab-3C (RAB3C), and reduced expression of cluster of differentiation 36 (CD36) observed in AMH tissue in comparison with controls.

CONCLUSIONS

Clinical AMH specimens display a different proteomic profile compared to control tissue. Of note, PNMT, MPZ, RAB3C, and CD36 are found to differentially expressed and can be potential targets for AMH, providing a theoretical basis for mechanistic exploration of AMH along with hypertension.

Thyroid Hormone Deficiency Suppresses Fetal Pituitary-Adrenal Function Near Term: Implications for the Control of Fetal Maturation and Parturition

Background: The fetal hypothalamic-pituitary-adrenal (HPA) axis plays a key role in the control of parturition and maturation of organ systems in preparation for birth. In hypothyroid fetuses, gestational length may be prolonged and maturational processes delayed. The extent to which the effects of thyroid hormone deficiency in utero on the timing of fetal maturation and parturition are mediated by changes to the structure and function of the fetal HPA axis is unknown. Methods: In twin sheep pregnancies where one fetus was thyroidectomized and the other sham-operated, this study investigated the effect of hypothyroidism on circulating concentrations of adrenocorticotrophic hormone (ACTH) and cortisol, and the structure and secretory capacity of the anterior pituitary and adrenal glands. The relative population of pituitary corticotrophs and the masses of the adrenal zones were assessed by immunohistochemical and stereological techniques. Adrenal mRNA abundances of key steroidogenic enzymes and growth factors were examined by quantitative polymerase chain reaction. Results: Hypothyroidism in utero reduced plasma concentrations of ACTH and cortisol. In thyroid-deficient fetuses, the mass of corticotrophs in the anterior pituitary gland was unexpectedly increased, while the mass of the zona fasciculata and its proportion of the adrenal gland were decreased. These structural changes were associated with lower adrenocortical mRNA abundances of insulin-like growth factor (IGF)-I and its receptor, and key steroidogenic enzymes responsible for glucocorticoid synthesis. The relative mass of the adrenal medulla and its proportion of the adrenal gland were increased by thyroid hormone deficiency in utero, without any change in expression of phenylethanolamine N-methyltransferase or the IGF system. Conclusions: Thyroid hormones are important regulators of the structure and secretory capacity of the pituitary-adrenal axis before birth. In hypothyroid fetuses, low plasma cortisol may be due to impaired adrenocortical growth and steroidogenic enzyme expression, secondary to low circulating ACTH concentration. Greater corticotroph population in the anterior pituitary gland of the hypothyroid fetus indicates compensatory cell proliferation and that there may be abnormal corticotroph capacity for ACTH synthesis and/or impaired hypothalamic input. Suppression of the development of the fetal HPA axis by thyroid hormone deficiency may contribute to the delay in fetal maturation and delivery observed in hypothyroid offspring.

Single-cell atlas of developing murine adrenal gland reveals relation of Schwann cell precursor signature to neuroblastoma phenotype

Neuroblastoma is the most common extracranial solid tumor and accounts for ∼10% of pediatric cancer-related deaths. The exact cell of origin has yet to be elucidated, but it is generally accepted that neuroblastoma derives from the neural crest and should thus be considered an embryonal malignancy. About 50% of primary neuroblastoma tumors arise in the adrenal gland. Here, we present an atlas of the developing mouse adrenal gland at a single-cell level. Five main cell cluster groups (medulla, cortex, endothelial, stroma, and immune) make up the mouse adrenal gland during fetal development. The medulla group, which is of neural crest origin, is further divided into seven clusters. Of interest is the Schwann cell precursor ("SCP") and the "neuroblast" cluster, a highly cycling cluster that shares markers with sympathoblasts. The signature of the medullary SCP cluster differentiates neuroblastoma patients based on disease phenotype: The SCP signature score anticorrelates with ALK and MYCN expression, two indicators of poor prognosis. Furthermore, a high SCP signature score is associated with better overall survival rates. This study provides an insight into the developing adrenal gland and introduces the SCP gene signature as being of interest for further research in understanding neuroblastoma phenotype.

Case Report: Three Rare Cases of Ectopic ACTH Syndrome Caused by Adrenal Medullary Hyperplasia

Ectopic ACTH syndrome (EAS) accounts for 10-20% of endogenous Cushing's syndrome (CS). Hardly any cases of adrenal medullary hyperplasia have been reported to ectopically secrete adrenocorticotropic hormone (ACTH). Here we describe a series of three patients with hypercortisolism secondary to ectopic production of ACTH from adrenal medulla. Cushingoid features were absent in case 1 but evident in the other two cases. Marked hypokalemia was found in all three patients, but hyperglycemia and osteoporosis were present only in case 2. All three patients showed significantly elevated serum cortisol and 24-h urinary cortisol levels. The ACTH levels ranged from 19.8 to 103.0pmol/L, favoring ACTH-dependent Cushing's syndrome. Results of bilateral inferior petrosal sinus sampling (BIPSS) for case 1 and case 3 confirmed ectopic origin of ACTH. The extremely high level of ACTH and failure to suppress cortisol with high dose dexamethasone suppression test (HDDST) suggested EAS for patient 2. However, image studies failed to identify the source of ACTH secretion. Bilateral adrenalectomy was performed for rapid control of hypercortisolism. After surgery, cushingoid features gradually disappeared for case 2 and case 3. Blood pressure, blood glucose and potassium levels returned to normal ranges without medication for case 2. The level of serum potassium also normalized without any supplementation for case 1 and case 3. The ACTH levels of all three patients significantly decreased 3-6 months after surgery. Histopathology revealed bilateral adrenal medullary hyperplasia and immunostaining showed positive ACTH staining located in adrenal medulla cells. In summary, our case series reveals the adrenal medulla to be a site of ectopic ACTH secretion. Adrenal medulla-originated EAS makes the differential diagnosis of ACTH-dependent Cushing's syndrome much more difficult. Control of the hypercortisolism is mandatory for such patients.

Stem cells, evolutionary aspects and pathology of the adrenal medulla: A new developmental paradigm

The mammalian adrenal gland is composed of two main components; the catecholaminergic neural crest-derived medulla, found in the center of the gland, and the mesoderm-derived cortex producing steroidogenic hormones. The medulla is composed of neuroendocrine chromaffin cells with oxygen-sensing properties and is dependent on tissue interactions with the overlying cortex, both during development and in adulthood. Other relevant organs include the Zuckerkandl organ containing extra-adrenal chromaffin cells, and carotid oxygen-sensing bodies containing glomus cells. Chromaffin and glomus cells reveal a number of important similarities and are derived from the multipotent nerve-associated descendants of the neural crest, or Schwann cell precursors. Abnormalities in complex developmental processes during differentiation of nerve-associated and other progenitors into chromaffin and oxygen-sensing populations may result in different subtypes of paraganglioma, neuroblastoma and pheochromocytoma. Here, we summarize recent findings explaining the development of chromaffin and oxygen-sensing cells, as well as the potential mechanisms driving neuroendocrine tumor initiation.

Effect of consuming high-fat diet on the morphological parameters of adrenal gland

OBJECTIVES

The incidence of obesity and obesity-assosiated pathologies continues to increase with profound adverse effects on health status in the developed countries.

BACKGROUND

We aimed to investigate the effect of high fat diet on the adrenal gland morphology.

METHODS

We fed the mice with either high-fat diet (60 % kcal from fat) or low-fat diet (10 % kcal from fat) for nine weeks. Unbiased stereological methods were used to evaluate the adrenal gland morphology. The sections were evaluated using Cavalieri's method and volume fraction approach. We calculated mean volume of adrenal gland, mean volume of adrenal medulla, VVadrenal medulla/adrenal gland, mean diameter of cromaffin cells, number of chromaffin cells in per unit volume (NVcc mm‒3), total number of cromaffin cells, VVzona glomerulosa/adrenal cortex, VVzona fasciculata/adrenal cortex , VVzona reticulosa/adrenal cortex.

RESULTS

The weight of adrenal gland, body weight intraperitoneal adipose tissue and adrenal gland weight in the obese mice significantly increased when compared with the control group. No changes were observed in the mean volume of adrenal gland, mean volume of adrenal medulla, VVzona glomerulosa/adrenal cortex, VVzona fasciculata/adrenal cortex, total number of cromaffin cells and diameter of cromaffin cells. However, NVcc mm-3 and VVzona reticulosa/adrenal cortex in the obese mice considerably increased compared with the control group.

CONCLUSION

The present results suggest that high fat diet adversely affects the adrenal gland morphology (Tab. 2, Fig. 6, Ref. 28).

Overexpression of P2X3 and P2X7 Receptors and TRPV1 Channels in Adrenomedullary Chromaffin Cells in a Rat Model of Neuropathic Pain

We have tested the hypothesis that neuropathic pain acting as a stressor drives functional plasticity in the sympathoadrenal system. The relation between neuropathic pain and adrenal medulla function was studied with behavioral, immunohistochemical and electrophysiological techniques in rats subjected to chronic constriction injury of the sciatic nerve. In slices of the adrenal gland from neuropathic animals, we have evidenced increased cholinergic innervation and spontaneous synaptic activity at the splanchnic nerve–chromaffin cell junction. Likewise, adrenomedullary chromaffin cells displayed enlarged acetylcholine-evoked currents with greater sensitivity to α-conotoxin RgIA, a selective blocker of α9 subunit-containing nicotinic acetylcholine receptors, as well as increased exocytosis triggered by voltage-activated Ca²⁺ entry. Altogether, these adaptations are expected to facilitate catecholamine output into the bloodstream. Last, but most intriguing, functional and immunohistochemical data indicate that P2X3 and P2X7 purinergic receptors and transient receptor potential vanilloid-1 (TRPV1) channels are overexpressed in chromaffin cells from neuropathic animals. These latter observations are reminiscent of molecular changes characteristic of peripheral sensitization of nociceptors following the lesion of a peripheral nerve, and suggest that similar phenomena can occur in other tissues, potentially contributing to behavioral manifestations of neuropathic pain.

Selective Pharmacogenetic Activation of Catecholamine Subgroups in the Ventrolateral Medulla Elicits Key Glucoregulatory Responses

Catecholamine (CA) neurons in the ventrolateral medulla (VLM) contribute importantly to glucoregulation during glucose deficit. However, it is not known which CA neurons elicit different glucoregulatory responses or whether selective activation of CA neurons is sufficient to elicit these responses. Therefore, to selectively activate CA subpopulations, we injected male or female Th-Cre+ transgenic rats with the Cre-dependent DREADD construct, AAV2-DIO-hSyn-hM3D(Gq)-mCherry, at one of four rostrocaudal levels of the VLM: rostral C1 (C1r), middle C1 (C1m), the area of A1 and C1 overlap (A1/C1), and A1. Transfection was highly selective for CA neurons at each site. Systemic injection of the Designer Receptor Exclusively Activated by Designer Drugs (DREADD) receptor agonist, clozapine-N-oxide (CNO), stimulated feeding in rats transfected at C1r, C1m, or A1/C1 but not A1. CNO increased corticosterone secretion in rats transfected at C1m or A1/C1 but not A1. In contrast, CNO did not increase blood glucose or induce c-Fos expression in the spinal cord or adrenal medulla after transfection of any single VLM site but required dual transfection of both C1m and C1r, possibly indicating that CA neurons mediating blood glucose responses are more sparsely distributed in C1r and C1m than those mediating feeding and corticosterone secretion. These results show that selective activation of C1 CA neurons is sufficient to increase feeding, blood glucose levels, and corticosterone secretion and suggest that each of these responses is mediated by CA neurons concentrated at different levels of the C1 cell group.

[Pheochromocytoma giant cystic: a case report]

The giant cystic pheochromocytoma is a rare adrenal tumor in the predominantly asymptomatic course; so many cases are not diagnosed until the time of surgery. The simple mobilization of the tumor is associated with the passage to the blood of large amounts of catecholamines and high morbidity and mortality. So the surgery itself and perioperative management are a huge challenge. This article describes the case of a malignant giant pheochromocytoma (35 cm) which occupied the entire right abdomen. Even with the preoperative diagnosis of pheochromocytoma, pharmacological blockade preoperative and intraoperative measures, the patient died shortly before the end of surgery.

Intrastriatal Cografts of Autologous Adrenal Medulla and Sural Nerve in MPTP-Induced Parkinsonian Macaques: Behavioral and Anatomical Assessment

To examine the effects of autologous sural nerve and adrenal medullary tissue intrastriatal cografts upon voluntary motor performance in parkinsonism, a non-human primate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model was employed to quantitatively assess skilled hand movements. Motor performance was studied in normal, MPTP-induced parkinsonian, and then cografted states. Reaction and movement times were prolonged and variability increased in experimental and control animals in the parkinsonian state. Animals undergoing autologous cografts demonstrated improved motor performance whereas the control animal continued in a chronic, stable parkinsonian state. Intrastriatal cografts of autologous adrenal medullary tissue and sural nerve resulted in good to excellent chromaffin cell survival. The mechanism of the restoration of function in the cografted monkeys remains to be determined.

Immunological Responses to Injury and Grafting in the Central Nervous System of Nonhuman Primates

Allogeneic transplantation for the therapy of human Parkinson's disease is being considered as a viable approach at several clinical centers worldwide. As an attempt to understand the basic biology of central nervous system (CNS) transplantation, our laboratory has developed an experimental nonhuman primate model for human Parkinson's disease and carried out preliminary studies directed at evaluating the potential pathology at the graft site. In addition, studies have been conducted to examine whether such transplantation procedures lead to specific and/or nonspecific immunologic sensitization of the host or results in generalized immunosuppression. Groups of rhesus macaques (Macaca mulatta) were either controls operated (n = 6), autografted with adrenal medullary and peripheral nerve tissue (n = 3), or allografted with fetal mesencephalic tissue (n = 6). Immunohistological studies demonstrated the presence of mononuclear cell infiltrates as early as 1 wk and up to 1 yr postoperatively, although the frequency of the infiltrating cells declined with time. The infiltrates consisted of variable numbers of cells which express CD2+, CD3+, CD4+, CD8+, CD19+, CD22+, CD25+, and CD68+. There appeared to be no difference in the frequency, kinetics, or phenotype of the infiltrating cells in operative controls compared with recipients of auto- or allografts. Tissue sections obtained postoperatively showed low levels of major histocompatibility complex (MHC) Class I antigens and no detectable level of MHC-Class II antigens in neural tissue. A small aliquot of tissue from the operative site was placed in vitro with media containing interleukin-2 (IL-2), which led to the exudation and growth of mononuclear cells that were predominantly CD4+ cells. Phenotypic studies of peripheral blood mononuclear cells (PBMC) from operative controls, auto- and allograft recipient monkeys performed at varying time periods postoperatively failed to show differences in the frequencies of subsets of T-cells, B-cells, NK-cells, or monocytes. Studies on aliquots of the same PBMC failed to show major functional differences in NK-cells, LAK cells, or response to polyclonal mitogens. Finally, recipients of allogeneic mesencephalic grafts failed to show evidence of donor-specific humoral or cellular sensitization. These data indicate that transplantation of autograft adrenal or allograft fetal mesencephalic tissues in the CNS of nonhuman primate did not induce detectable donor-specific sensitization nor nonspecific immunosuppression.

Expression of Extracellular Signal-regulated Kinase 5 and Ankyrin Repeat Domain 1 in Composite Pheochromocytoma and Ganglioneuroblastoma Detected Incidentally in the Adult Adrenal Gland

Composite pheochromocytoma (cPC) is extremely rare, arising in the adrenal medulla as a mixture of PC and other tumors of neural origin. We herein report on a case of adrenal incidentaloma post-operatively diagnosed as cPC with ganglioneuroblastoma (GNBL). The PC component had 7 points on the PASS, a Ki-67 index of 5.1%, a focal absence of sustentacular cells, and no genetic aberrations in succinate dehydrogenase subunit B. The GNBL component exhibited no N-myc amplification. Tumor cells of both components were stained positively for extracellular signal-regulated kinase 5 and ankyrin repeat domain 1. The aberrant activation of growth signaling may play a role in the marginal malignancy of cPC.

Morphology, Biochemistry, and Pathophysiology of MENX-Related Pheochromocytoma Recapitulate the Clinical Features

Pheochromocytomas (PCCs) are tumors arising from neural crest-derived chromaffin cells. There are currently few animal models of PCC that recapitulate the key features of human tumors. Because such models may be useful for investigations of molecular pathomechanisms and development of novel therapeutic interventions, we characterized a spontaneous animal model (multiple endocrine neoplasia [MENX] rats) that develops endogenous PCCs with complete penetrance. Urine was longitudinally collected from wild-type (wt) and MENX-affected (mutant) rats and outputs of catecholamines and their O-methylated metabolites determined by mass spectrometry. Adrenal catecholamine contents, cellular ultrastructure, and expression of phenylethanolamine N-methyltransferase, which converts norepinephrine to epinephrine, were also determined in wt and mutant rats. Blood pressure was longitudinally measured and end-organ pathology assessed. Compared with wt rats, mutant animals showed age-dependent increases in urinary outputs of norepinephrine (P = .0079) and normetanephrine (P = .0014) that correlated in time with development of tumor nodules, increases in blood pressure, and development of hypertension-related end-organ pathology. Development of tumor nodules, which lacked expression of N-methyltransferase, occurred on a background of adrenal medullary morphological and biochemical changes occurring as early as 1 month of age and involving increased adrenal medullary concentrations of dense cored vesicles, tissue contents of both norepinephrine and epinephrine, and urinary outputs of metanephrine, the metabolite of epinephrine. Taken together, MENX-affected rats share several biochemical and pathophysiological features with PCC patients. This model thus provides a suitable platform to study the pathogenesis of PCC for preclinical translational studies aimed at the development of novel therapies for aggressive forms of human tumors.

Diverse proportion in composite pheochromocytoma-ganglioneuroma may induce varied clinical symptom: comparison of two cases

Composite pheochromocytoma-ganglioneuroma is extremely rare. We described two cases of composite pheochromocytomas in the adrenal medullar. Case 1 was a 70-year-old male presenting with lower abdominal pain and normal blood electrolytes. Case 2 was a 48-year-old female with palpitation and back tenderness. Biochemical investigations showed hypocalcium, hypokalemia and high level of vma. The histological images and the immunohistochemical staining demonstrated the two cases composed of pheochromocytoma and ganglioneuromoma components. Ganglioneuroma component in case 2 accounted for more proportion than that in case 1. We speculated that the varied clinical symptoms were related with the diverse proportions in composite pheochromocytome-ganglioneuroma.

Studies of neurotransmitter release in the pathogenesis of hypertension

Studies using a sensitive radioenzymatic assay for plasma noradrenaline suggest there is a selective overactivity of the sympathetic nervous system in essential hypertension. Methodology which allows the study of local sympathetic turnover in CNS nuclei and peripheral blood vessels is described. This approach has been used to study the non-innervated sympathetic turnover phaeochromocytoma. It is suggested that studies of local regulatory mechanism in neurotransmitter release are required to give a greater understanding of the central and peripheral role of the sympathetic nervous system in the pathogenesis of hypertension.

A rarely seen case among retroperitoneal mass lesions: paraganglioma

Pheochromocytomas are rarely seen cathecolamine-secreting neuroendocrine tumors. Diagnosis, treatment, and prognosis of this rarely seen condition have been discussed. In this study, a retroperitoneal paraganglioma with a diameter of 27 mm was detected in a 29-years old nephrectomized male patient. In our case, in reevaluations performed after definitive establishment of the diagnosis, any abnormal radiological signs suggesting a metastatic lesion were not detected. During the postoperative period the patient was referred to the clinics of endocrinology, and oncology for medical follow-up. In the differential diagnosis of retroperitoneal mass lesions, pheochromocytoma/paraganglioma should not be forgotten. Besides, for malignant tumors chemoradiotherapy, and for benign functional tumors medical treatment should be applied.

[Diagnosis and treatment of adrenal medullary hyperplasia]

OBJECTIVE

To explore the clinical characters of adrenal medullary hyperplasia (AMH).

METHODS

The clinical data of 7 cases of AMH admitted from 1996 to 2013 were analyzed with a review of literature.

RESULTS

There were 3 males and 4 females with a median age of 36 (23-69) years. All had hypertension at first diagnosis and 2 were paroxysmal. Computed tomography (CT) scan revealed unilateral adrenal nodule in all cases, including left (n = 5) and right (n = 2) side. The diameter of nodules was 0.9 cm to 3.0 cm.Hypokalemia was found in 2 cases. And 24-hour output of urine catecholamine was higher than normal level in 2 cases. An abnormal rise of 24-hour output of urine free cortisol was found in 1 case with a lower level of adrenocorticotropic hormone (ACTH) simultaneously while a lower level of plasma renin activity in vertical position was found in another case. Three patients received (131)I-meta-iodobenzylguanidine scan and one had positive result. Pre-operative diagnosis included pheochromocytoma (n = 2), adrenocortical adenoma (n = 3) (2 aldosterone-producing adenomas, 1 Cushing adenoma) and undetermined adrenal tumor (n = 2). All underwent surgery, including unilateral adrenalectomy (n = 4) and resection of adrenal disease (n = 3). All cases had a pathologic diagnosis of AMH. One had concurrent Cushing adenoma while another with cortical hyperplasia.One case achieved normotension postoperatively while others showed varying decreases of blood pressure, but remained hypertensive.

CONCLUSION

With a common feature of hypertension, AMH is difficult to diagnose preoperatively. CT scan has a certain diagnostic significance and a definite diagnosis depends on pathological examination; because of inaccurate preoperative and intraoperative diagnosis, the extent of surgery may be incomplete and results in unsatisfied outcomes.

The adrenal medulla and extra-adrenal paraganglia: then and now

The past 25 years have witnessed revolutionary changes in the care of patients with pheochromocytomas and extra-adrenal paragangliomas. Germline mutations of at least 13 genes are now associated with tumor development, a greater degree of hereditary susceptibility than for any other human neoplasm. Somatic mutations, either of the same genes or of several additional ones with closely related functions, are also increasingly recognized. Clinicians are now aware of the genetic implications of a pheochromocytoma or paraganglioma. All patients are therefore offered genetic testing and receive lifelong surveillance. Almost all of the mutated genes have well-described correlations with clinical and biochemical phenotypes. Tumors arising in patients with mutations of the SDHB gene have at least a 30 % chance of metastasizing and typically produce norepinephrine and/or dopamine. Assay of plasma-free metanephrines serves as a highly sensitive and specific biochemical screen for the presence of catecholamine-producing tumors, and the dopamine metabolite methoxytyramine serves as a useful marker for detecting minimally functional tumors or their metastases. New functional imaging techniques provide highly sensitive tumor localization. In addition to differential diagnosis, pathologists play new roles in helping to identify hereditary disease and guiding the sequence of genetic testing.

Investigating the role of adrenal cortex in organization and differentiation of the adrenal medulla in mice

Functions of adrenal medulla, particularly synthesis of catecholamine, are under the control of glucocorticoids produced by the cortex. To further investigate whether development/differentiation of the adrenal medulla is associated with proper organization of the adrenal cortex, we examined development of the medulla in four different mouse models with various defects in the adrenal cortex. By using the Sf1/Cre mouse line that inactivates/activates genes in Steroidogenic factor 1 (SF1)-positive cells of the fetal adrenal cortex, we produced mice that exhibit either (1) cortex hypoplasia, (2) progressive degeneration of fetal adrenal cortex, (3) cortex dysgenesis, or (4) cortex-medulla disorganization. The formation of phenylethanolamine N-methyltransferase (PNMT)-positive medulla in all models indicates that differentiation of adrenal medulla is independent of the growth of adrenal cortex. However, the misplaced/dysgenic medulla in embryos where β-catenin expression is altered, suggests that the β-catenin pathway in the adrenal cortical cells plays an indirect role in controlling proper organization of the adrenal medulla.

[Pheochromocytomas in adrenal medulla or extra-adrenal and multiple endocrine neoplasms:a clinicopathologic analysis of 181 cases]

OBJECTIVE

To analyze the change in the incidence of pheochromocytomas in adrenal medulla or extra-adrenal and multiple endocrine neoplasm type 2 (MEN2), to summarize the clinical characteristics of benign, potentially malignant and malignant pheochromocytomas and to investigate the correlation between clinical manifestations and pathological changes.

METHODS

Statistic analysis was performed to detect the incidence, constituent ratio, mean diagnostic age, sex proportion and correlation between clinical manifestions and pathologic changes in pheochromocytomas in adrenal medulla or extra-adrenal gland and MEN2 from 1993 to 2008 in the Department of Pathology, the General Hospital of Tianjin Medical University with Runs test, ANOVA, t test and chi-square test.

RESULTS

The total number of biopsies within the 16 years was 167 702 cases (average 10 481 cases per year). The numbers (detectable rate) of total adrenal diseases, pheochromocytomas in adrenal medulla and extra-adrenal glands were 910 (0.54%), 139 (0.08%), and 42 (0.03%) cases, respectively. The numbers (constituent ratio) of benign, potentially malignant and malignant of pheochromocytomas in adrenal medulla were 102 cases (73.4%), 29 cases (20.9%) and 8 cases (5.7%), respectively; in the 102 cases of benign tumors, patients with MEN2 were 8 (7.8%); the three groups of the tumors in extra-adrenal sites were 18 (42.8%) cases, 12 (28.6%) cases and 12 (28.6%) cases. There were no changes in the detectable rate and constituent ratio of adrenal diseases, benign, potential malignant and malignant pheochromocytomas in adrenal medulla or extra-adrenal glands and patients with MEN2 during the past 16 years (P > 0.05), but there was a tendency that malignant transformation was gradually increased with age, which was more commonly found in male patients than females. The mean age at diagnosis of patients with benign and potentially malignant pheochromocytomas was 42.7 years (ranged from 10 - 74 years), and 40.1 years (13 - 66 years), respectively, which were younger than patients with malignant pheochromocytomas (51.6 years, P < 0.05); the mean age of patients with benign and potentially malignant pheochromocytomas in extra-adrenal sites was 43.1 years (ranged from 20 - 75 years) and 45.2 years (28 - 65 years) that were older than those with malignant (37.8 years, ranged from 14 - 58 years, P < 0.05). It was spectacular that patients with malignant pheochromocytoma in adrenal medulla (51.6 years) were older than that in extra-adrenal sites (37.8 years); all the patients with MEN2 were female benign pheochromocytoma in adrenal medulla, whose age (38.9 years) was younger than that of benign lesions (42.7 years, P < 0.05), in which thyroid medullary carcinoma appeared early than pheochromocytomas in adrenal medulla. The detectable rate of hypertension in patients with malignant pheochromocytomas in adrenal medulla and in extra-adrenal sites were less than that in benign and potentially malignant ones (P < 0.05). The bilateral lesions more commonly found in malignant pheochromocytoma (25.0%) than benign (15.7%) and potentially malignant pheochromocytomas (6.9%) only in adrenal medulla. Relapse rates in both adrenal and extra-adrenal tumors were rising from benign (11.8%, 0), potentially malignant (13.8%, 25.0%), to malignant (33.3%, 37.5%) groups; the average diameter of pheochromocytomas in both adrenal and extra-adrenal sites was increasing from benign (4.2 cm, 4.0 cm), potentially malignant (5.3 cm, 5.6 cm) to malignant (7.3 cm, 6.9 cm) groups (P < 0.05).

CONCLUSIONS

The diagnostic criteria of benign, potentially malignant and malignant pheochromocytomas in adrenal medulla and in extra-adrenal sites are well established according to the WHO classification of endocrine tumors (2004). The closer relationship is found between clinical manifestations and pathologic changes. The definite type and nature of pheochromocytomas are mainly rested upon the pathologic examination.

Rostroventrolateral medullary neurons modulate glucose homeostasis in the rat

Several lines of evidence support the view that the premotor sympathetic input to the adrenal gland arises from the rostroventrolateral medulla (RVLM). The aim of this study was to determine whether RVLM neurons play a role in glucose homeostasis. We identified RVLM neurons that control epinephrine secretion by searching for medullospinal neurons that responded to neuroglucoprivation induced by systemic 2-deoxyglucose (2-DG) administration. We tested the effect of disinhibition of the RVLM on arterial blood pressure and plasma glucose concentration. RVLM medullospinal barosensitive neurons (n = 17) were either unaffected or slightly inhibited by 2-DG. In contrast, we found a group (n = 6) of spinally projecting neurons that were excited by 2-DG administration. These neurons were not barosensitive and had spinal conduction velocities in the unmyelinated range (<1 m/s). These neurons may mediate epinephrine secretion and participate in the counterregulatory responses to neuroglucoprivation. To test the hypothesis that activation of the RVLM leads to adrenomedullary activation and subsequent hyperglycemia, we applied the GABA(A) antagonist bicuculline to the RVLM and measured blood pressure, heart rate, and blood glucose in rats with intact adrenals or after bilateral adrenalectomy. Disinhibition of the RVLM resulted in hypertension, tachycardia, and hyperglycemia (4.9 ± 0.3 to 14.7 ± 0.9 mM, n = 5, P < 0.05). Adrenalectomy significantly reduced the hyperglycemic response but did not alter the cardiovascular responses. These data suggest that the RVLM is a key component of the neurocircuitry that is recruited in the counterregulatory response to hypoglycemia.

Microarray analysis reveals differential expression of benign and malignant pheochromocytoma

The diagnosis of a malignant pheochromocytoma (PC) can only be established by the presence of distant metastases, but a subset of apparently benign PCs develop metastases. We have employed a microarray analysis to identify a typical gene expression profile which distinguishes malignant from benign PC. Total RNA was isolated from fresh-frozen tissue of five benign and five malignant PCs. The reference consisted of laser microdissected tissue from normal adrenal medulla. After generating Cy3- and Cy5-fluorescently labeled cDNAs, F-chips containing 11 540 spots were hybridized. Data were analyzed with the IMAGENE 3.0 software. Gene expression levels were validated by real-time (RT)-PCR and immunohistochemistry (IHC). The analysis revealed a more than twofold difference in expression between benign and malignant PCs in 132 genes: 19 were up-regulated and 113 were down-regulated. Expression differences of six genes (calsequestrin, NNAT, neurogranin, secreted protein acidic and rich in cysteine (SPARC), EGR2, and MAOB) were confirmed by RT-PCR in 25 PCs. IHC for calsequestrin revealed an overexpression in malignant PCs (7/10 vs 1/10, P=0.03). Comparative analysis by microarray of all ten PCs (benign/malignant) versus normal adrenal medulla revealed a more than twofold expression difference in 455/539 and 491/671 genes respectively. Several of these genes are known to participate on adrenal tumorigenesis, potential tumor suppressor genes, and oncogenes. Comprehensive gene expression analysis of malignant and benign PCs revealed different gene profiles, which could be used to discriminate between malignant and benign PCs. Based on these findings, the strategy for further follow-up and treatment could be modified accordingly.

Proceedings of the 2009 National Toxicology Program Satellite Symposium

The National Toxicology Program (NTP) Satellite Symposium is a one-day meeting that is held in conjunction with the annual Society of Toxicologic Pathology (STP) meeting. The topic of the 2009 Symposium was "Tumor Pathology and INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Nomenclature." The goal of this article is to provide summaries of each speaker's presentation, including the diagnostic or nomenclature issues that were presented, along with a few select images that were used for voting. The results of the voting process and interesting points of discussion that were raised during the presentation are also provided. A supplemental file with voting choices and voting results for each case presented at the symposium is available at http://tpx.sagepub.com/supplemental.

POSTMORTEM CHANGES IN THE CENTRAL NERVOUS SYSTEM AND ADRENAL MEDULLA OF THE HEROIN ADDICTS

This study describes the pathological changes in 20 heroin addicts (12 male and 8 female) autopsied 24 h after sudden death. The central nervous system (including the pituitary body) and the adrenal medulla were studied, along with those from age-matched controls who died from traffic accidents. Immunohistochemistry and histological (Hematoxylin and eosin) observation were performed. Some neuronal cells in every region of the CNS were positive for opioid receptors but these cells were most numerous in the hippocampus. Positive opioid fibers were most abundant in the basal ganglia region. Histopathology indicated coagulative changes of cytoplasm and dissolution of Nissl bodies of neuron. Edema of nerve fibers was frequently demonstrated. Pituitary body showed an evident decrease or even absence of basophils in the pars anterior. The adrenal medulla featured a down regulation of chromaffin granules. Degeneration of CNS neurons and fibers, alterations in hormonal and blood pressure regulation therefore would be the prime targets of heroin addiction in human subjects.

Conditional inactivation of glucocorticoid receptor gene in dopamine-beta-hydroxylase cells impairs chromaffin cell survival

Glucocorticoid hormones (GCs) have been thought to determine the fate of chromaffin cells from sympathoadrenal progenitor cells. The analysis of mice carrying a germ line deletion of the glucocorticoid receptor (GR) gene has challenged these previous results because the embryonic development of adrenal chromaffin cells is largely unaltered. In the present study, we have analyzed the role of GC-dependent signaling in the postnatal development of adrenal chromaffin cells by conditional inactivation of the GR gene in cells expressing dopamine-beta-hydroxylase, an enzyme required for the synthesis of noradrenaline and adrenaline. These mutant mice are viable, allowing to study whether in the absence of GC signaling further development of the adrenal medulla is affected. Our analysis shows that the loss of GR leads not only to the loss of phenylethanolamine-N-methyl-transferase expression and, therefore, to inhibition of adrenaline synthesis, but also to a dramatic reduction in the number of adrenal chromaffin cells. We provide evidence that increased apoptotic cell death is the main consequence of GR loss. These findings define the essential role of GCs for survival of chromaffin cells and underscore the specific requirement of GCs for adrenergic chromaffin cell differentiation and maintenance.

Morphological and microvascular changes of the adrenal glands in streptozotocin-induced long-term diabetic rats

It has been known that diabetes mellitus is associated with hyperfunction of the adrenal gland. However, the structural changes of adrenal gland in diabetes have rarely been studied. The aims of this study were to investigate the morphological and microvascular alterations in streptozotocin (STZ)-induced long-term diabetic rats. Twelve male Sprague-Dawley rats were divided into diabetic (n=8) and control (n=4) groups. Each diabetic rat was induced by an intraperitoneal injection of STZ (60 mg/kg) in citrate buffer (pH 4.5). Control rats were intraperitoneally injected with the same amounts of the buffer. These animals were sacrificed at 20 weeks after the injections. The adrenal glands were processed for the morphological and microvascular studies by using conventional light microscopy (LM) and vascular corrosion cast technique combined with scanning electron microscopy (SEM), respectively. In the diabetic group, the cells in zona glomeruloza (ZG) became atrophied and the thickness of this zone was found to be less than that of the controls. In the zona fasciculata (ZF) and zona reticularis (ZR), the hypertrophic cells were investigated in both layers. The degenerated chromaffin and hypertrophic sympathetic ganglion cells in the adrenal medulla were observed. Also some degenerated ganglion cells were found. Additionally, lymphocyte infiltration, macrophages and amyloidosis were found in the adrenal medulla of long-term diabetic rats with renal failure. Under the SEM observation, the luminal diameters of capillaries in the diabetic group were dilated in all zones. In addition, these capillaries in the ZF and ZR were arranged in tortuous courses. This study demonstrates morphological and microvascular changes in the adrenal gland of diabetic rats which are in accordance with the hormonal changes reported by previous investigators.

Retroperitonial liposarcoma mimicking pheochromocytoma

The authors report the case of a 46-year-old woman who presented with a 4 month history of paroxystic and recent hypertension accompagned by headaches, tachycardia and sweating. The patient had decreased appetite with epigastric discomfort and abdominal distension. Physical examination was initially normal with mainly normal tension and no abdominal or lombar mass in palpation. While hospitalised, she developed paroxystic crisis of flush, headaches and hypertension of 190/100 mmHg. Biological findings revealed hypokaliemia and normal kaliuria on 3 day samples, with normal glycaemia and normal creatininaemia. Hormonal investigation revealed elevated metanephrines (3 mg/24 hours). Magnetic resonance imaging showed an 11 cm x 8.5 cm retroperitoneal mass with an enhanced signal in T2, a hypotrophic non-functional left kidney and no adrenal adenoma. Clinical and hormonal features suggested a diagnosis of pheochromocytoma. After preoperative medication, open excision, including left radical nephrectomy and adrenalectomy, normalized the catecholamine urinary level, resolved hypokalemia, and improved hypertension. Pathologic examination revealed a well-differentiated liposarcoma, without any pheochromocytoma component, and left adrenal hyperplasia. The tumour cells were immunonegative for chromogranin A. No metastatic lesion was identified by thoraco-abdominal computed tomography.

The complement anaphylatoxin C5a induces apoptosis in adrenomedullary cells during experimental sepsis

Sepsis remains a poorly understood, enigmatic disease. One of the cascades crucially involved in its pathogenesis is the complement system. Especially the anaphylatoxin C5a has been shown to have numerous harmful effects during sepsis. We have investigated the impact of high levels of C5a on the adrenal medulla following cecal ligation and puncture (CLP)-induced sepsis in rats as well as the role of C5a on catecholamine production from pheochromocytoma-derived PC12 cells. There was significant apoptosis of adrenal medulla cells in rats 24 hrs after CLP, as assessed by the TUNEL technique. These effects could be reversed by dual-blockade of the C5a receptors, C5aR and C5L2. When rats were subjected to CLP, levels of C5a and norepinephrine were found to be antipodal as a function of time. PC12 cell production of norepinephrine and dopamine was significantly blunted following exposure to recombinant rat C5a in a time-dependent and dose-dependent manner. This impaired production could be related to C5a-induced initiation of apoptosis as defined by binding of Annexin V and Propidium Iodine to PC12 cells. Collectively, we describe a C5a-dependent induction of apoptotic events in cells of adrenal medulla in vivo and pheochromocytoma PC12 cells in vitro. These data suggest that experimental sepsis induces apoptosis of adrenomedullary cells, which are responsible for the bulk of endogenous catecholamines. Septic shock may be linked to these events. Since blockade of both C5a receptors virtually abolished adrenomedullary apoptosis in vivo, C5aR and C5L2 become promising targets with implications on future complement-blocking strategies in the clinical setting of sepsis.

Association of an oversized adrenal cortical adenoma with expression of pheochromocytoma-like neurosecretory features

Abnormal stimulation of adrenal function may be either direct, affecting similarly cortical and medullary secretion, or indirect affecting primarily the medulla. Indirect activation of clinically detectable adrenomedullary function may develop as a physical consequence of a non-functional adrenal tumor exerting pressure on the medulla by its size, location and direction of growth. Our case of an oversized and overweight adrenal tumor associated with expression of late-onset pheochromocytoma-like clinical symptoms may be explained by the physical indirect rather than the biological direct activation of adrenomedullary function like hyperplasia or cancer.

Exploration of cytotoxic effect of malathion on some rat organs structure

Widespread use of insecticides has caused several risks to public health. This work was designed to investigate the histological changes in Liver, lung, adrenal medulla and testis of Wistar rats treated with malathion, administered intra peritoneally at a dose of 33,051 mg/kg per day. Exposure to the malathion, for 40 days, induced histological alterations: regular arrangement of hepatocytes with dilated sinusoidal spaces, thickened Lung epithelium, regression of adrenal medulla with congestion and disruption of the germ Line. These alterations represent the signs of cytotoxicity of malathion in Wistar rats.

A diagnostic approach to adrenal cortical lesions

The adrenal gland is not a common specimen in surgical pathology practice as, until recently, adrenal tumors were recognized in life only if associated with hypersecretion of hormones or evidence of malignancy. However, adrenal nodules are not uncommon at autopsy, and the number of these found in life is now increasing as they are identified when the abdomen is scanned for the investigation of other diseases using computed tomography or magnetic resonance imaging. It is therefore becoming increasingly important for the surgical pathologist to be aware of the range of pathology in the gland and to understand how to approach the specimens. This short review will deal with lesions of the adrenal cortex.

[A new approach to the identification and the interpretation of the various forms of cribra orbitalia]

The so-called cribra orbitalia lesion was described for the first time in 1885 by H. Welcker. Since then the cribriform tectum of the orbit has provoked the most varied pathogenic interpretations. However for 40 years the whole paleopathologist community agreed to recognize that anaemia and generally deficiency in iron, food or infections were the causes of medullary hyperplasia which would be the alone responsible for the damage. Through new macroscopic explorations and new understanding of the genesis of the lesion, the author does not admit the principle of an universal hyperplasia but he suggests to distinguish three causes ofcribra orbitalia: the anatomic variations, the osteoperiostitis, the cortical erosion.

Adrenergic differentiation and Ret expression in rat pheochromocytomas

Pheochromocytomas are catecholamine-producing tumors of the adult adrenal medulla. They are rare in humans and most other species but common in laboratory rats. However, the relevance of rat pheochromocytomas as a model for their human counterparts is uncertain. Previous studies of spontaneous and drug-induced rat pheochromocytomas and the PC12 pheochromocytoma cell line suggested a distinctive noradrenergic phenotype, possibly reflecting origin from a progenitor not present in the adult human adrenal. In this study, we studied 31 pheochromocytomas derived from test and control male and female rats in toxicologic studies for expression of the epinephrine-synthesizing enzyme phenylethanolamine-N-methyltransferase (PNMT) and the receptor tyrosine kinase Ret. PNMT, which defines adrenergic chromaffin cells, is frequently expressed in human pheochromocytomas, often in tumors that also overexpress RET. We also tested for the expression of the cell cycle checkpoint protein p27(Kip1), which recently was reported absent in pheochromocytomas from a strain of rats with a hereditary mixed multiple endocrine neoplasia (MEN)-like syndrome. Using immunoblots, we demonstrated PNMT expression in almost 50% of the 31 tumors, although often at lower levels than in normal rat adrenal medulla. The majority of tumors overexpressed Ret. There was no apparent correlation between PNMT and Ret. However, in this study, PNMT expression was strongly associated with tumors arising in female rats, while overexpression of Ret did not show a sex predilection. Robust expression of p27(Kip1) was seen in all tumors from the toxicologic studies and also in a small sample of pheochromocytomas from Long-Evans rats, which were reported to have a mixed MEN-like syndrome in the 1980s. The present results show that rat pheochromocytomas have greater phenotypic diversity than previously believed and greater similarity to their human counterparts with respect to these two important markers. Loss of p27(Kip1) does not appear to account for the high frequency of pheochromocytomas in commonly utilized rat strains.

Increase of beta-endorphin secretion by syringin, an active principle of Eleutherococcus senticosus, to produce antihyperglycemic action in type 1-like diabetic rats

We employed streptozotocin-induced diabetic rats (STZ-diabetic rats) as type 1 diabetes-like animal models to investigate the mechanism(s) of antihyperglycemic action produced by syringin, an active principle purified from the rhizome and root part S of ELEUTHEROCOCCUS SENTICOSUS (Araliaceae). Bolus intravenous (i. v.) injection of syringin dose-dependently decreased the plasma glucose of STZ-diabetic rats in 30 minutes in a way parallel to the increase of plasma beta-endorphin-like immunoreactivity (BER). Syringin enhanced BER release from the isolated adrenal medulla of STZ-diabetic rats in a concentration-dependent manner from 0.001 to 10 micromol/l. Bilateral adrenalectomy in STZ-diabetic rats eliminated the activities of syringin (1 mg/kg, i. v.) including the plasma glucose-lowering effect and the plasma BER-elevating effect. Also, syringin failed to lower plasma glucose in the presence of micro-opioid receptor antagonists and/or in the micro-opioid receptor knockout diabetic mice. In conclusion, the obtained results suggest that syringin can enhance the secretion of beta-endorphin from adrenal medulla to stimulate peripheral micro-opioid receptors resulting in a decrease of plasma glucose in diabetic rats lacking insulin.

Pheochromocytoma: an update on genetics and management

Pheochromocytomas (PHEOs) are rare neoplasms that produce catecholamines and usually arise from the adrenal medulla and are considered to be an adrenal paraganglioma (PGL). Closely related tumors of extraadrenal sympathetic and parasympathetic paraganglia are classified as extraadrenal PGLs. Most PHEOs are sporadic, but a significant percentage (approximately 25%) may be found in patients with germline mutations of genes predisposing to the development of von Hippel-Lindau disease, neurofibromatosis 1, multiple endocrine neoplasia type 1 (MEN1) and 2 (MEN2), and the PGL/PHEOs syndrome, based on the described mutations of the genes for succinate dehydrogenase subunit D (SDHD), B (SDHB), and C (SDHC). As one out of four PHEOs turns out to be a hereditary clinical entity, screening for genetic alterations is important, as it provides useful information for a rational diagnostic approach and management. This review discusses the genetics, the pathophysiology of hypertension, the clinical picture, the biochemical and imaging diagnosis, and the preferred therapeutic approach for PGLs/PHEOs. Furthermore, it emphasizes the need for genetic testing in cases with apparently sporadic PHEOs.

The effect of leptin on adrenal glands in rats with streptozotocin-induced diabetes: an experimental study

OBJECTIVE

To determine the cross-section area of adrenal medulla and the percentage of Ki-67 (a proliferation marker) of the adrenal gland in diabetic rats after leptin injection.

STUDY DESIGN

Twenty-nine male Wistar rats were randomly divided into 3 groups: control (C) group (n = 9), diabetes mellitus (DM) group (n = 10) and leptin-injected diabetes mellitus (DM+L) group (n = 10). Experimental DM was induced by a single intraperitoneal dose of streptozotocin (40 mg/kg). After this, leptin (100 microg/kg) was injected subcutaneously for a period of 2 weeks in the diabetic group.

RESULTS

An atrophy of adrenal medulla in the DM group was observed, and this atrophy returned to normal morphology after injection of leptin. In addition, an increase in the Ki-67 percentage was demonstrated in the zona reticularis layers in the DM+L group.

CONCLUSION

Our study indicated that leptin stimulates the sympathoadrenal system and the androgen producing adrenal cortex in DM rats.

Precursor Lesions of the Adrenal Gland

OBJECTIVE

To review the existing literature for evidence that adrenocortical and adrenomedullary tumours develop through a multistep process of carcinogenesis.

RESULTS

In the adrenal cortex hyperplasia and adenomas are frequently observed tumours or tumour-like conditions. In contrast, adrenocortical carcinomas are rare. Based on well-validated histopathological scoring systems, benign and malignant adrenocortical tumours can be separated, although a small subset of tumours remains hard to classify. Although extensive follow-up studies might argue against multistep carcinogenesis, analysis of chromosomal imbalances and gene expression profiling studies in these tumours are inconclusive and could give support for both multistep pathogenesis or de novo genesis of carcinomas. A major limit to most of these studies is the small sample size and the lack of extensive clinical (follow-up) data. In the adrenal medulla, pheochromocytomas (PCC) are the most frequent tumours in adults, with an incidence of 8 per million. They can be divided into benign and malignant PCC, but the distinction can only be made when metastases are present. Arbitrarily, lesions of less than 1 cm in diameter are called hyperplastic, but it should be expected that the majority of these are early lesions and if left in situ would grow to classify as PCC. In contrast to cortical tumours, the frequent 1p and 3q loss as an early event in tumourigenesis of benign PCC is verified in multiple studies. However, studies in malignant PCC yield divergent results, due to the small numbers analysed.

CONCLUSION

Taken together, there appears to be a relationship between cortical and medullary hyperplasia on the one hand and cortical adenomas and PCC on the other. However, whether there is a transition from benign to malignant tumours, both cortical and medullary, remains to be determined.

The optimal imaging of adrenal tumours: a comparison of different methods

Computed tomography (CT; unenhanced, followed by contrast-enhanced examinations) is the cornerstone of imaging of adrenal tumours. Attenuation values of <10 Hounsfield units on an unenhanced CT are practically diagnostic for adenomas. When lesions cannot be characterised adequately with CT, magnetic resonance imaging (MRI) evaluation (with T1- and T2-weighted sequences and chemical shift and fat-suppression refinements) is sought. Functional nuclear medicine imaging is useful for adrenal lesions that are not adequately characterised with CT and MRI. Scintigraphy with [(131)I]-6-iodomethyl norcholesterol (a labelled cholesterol analogue) can differentiate adrenal cortical adenomas from carcinomas. Phaeochromocytomas appear as areas of abnormal and/or increased uptake of [(123)I]- and [(131)I]-meta-iodobenzylguanidine (a labelled noradrenaline analogue). The specific and useful roles of adrenal imaging include the characterisation of tumours, assessment of true tumour size, differentiation of adenomas from carcinomas and metastases, and differentiation of hyperfunctioning from non-functioning lesions. Adrenal imaging complements and assists the clinical and hormonal evaluation of adrenal tumours.

Cytologic features of malignant cystic pheochromocytoma: a case report

BACKGROUND

Image-guided fine needle aspiration (FNA) biopsy of deep-seated lesions (e.g., retroperitoneal) has aided preoperative diagnosis and treatment planning. Fine needle aspiration biopsy of pheochromocytomas traditionally has been contraindicated by many authors because of possible hypertensive crisis and fatal hemorrhage. Cytologic features are described for a malignant pheochromocytoma (greater percentage of smaller cells and absence of hyaline globules) with extensive cystic degeneration that was later confirmed by histopathologic, immunohistochemical and ultrastructural studies.

CASE

An elderly man was diagnosed with renal cell carcinoma based on clinical examination and ultrasonography. FNA performed on the mass revealed interesting features of pheochromocytoma with an abundance of small cells.

CONCLUSION

The cytopathologist should be aware of the cytologic features of pheochromocytoma so as to detect a clinically unsuspected lesion. An increased percentage of smaller cells may be indicative of aggressive tumors.

[Morphometric parameters of rat adrenals in the dynamics of general hypothermia]

In this study, some morphometric parameters of adrenals in outbred albino male rats were compared in the dynamics of general hypothermia at the ambient temperature of -18 degrees C. It was shown that in the course of general hypothermia, the increase of blood vessel relative volume in zona reticularis and in adrenal medulla was accompanied by the augmentation of nucleus size of adrenocorticocytes (mainly in zona fasciculata). Zona fasciculata reacted with a significant increase of blood vessel relative volume during the 1st hour of cold exposure, henceforth the parameters remained unchanged. Blood vessel relative volume in the left adrenal was found to significantly exceed that in the right adrenal. In zona glomerulosa of the left adrenal, blood vessel relative volume was reduced, while that one in zona glomerulosa of the right adrenal remained unchanged during the whole experiment. Volume density of mitochondria in the endocrine cells of zona fasciculata was found to increase, this effect being more pronounced in the right adrenal as compared to the left one. In the cells of both glands, the volume density of lipid inclusions was gradually reduced, while the relative volume of nucleoli was variable and there were no statistically significant changes detected during the course of hypothermia.

Treatment of bilateral pheochromocytoma and adrenal medullary hyperplasia

The risk for bilateral tumors and long-term outcome after conservative cortical-sparing adrenal surgery was studied in a consecutive single-center series. One hundred fifty-four patients were operated on (1950-2004) for pheochromocytoma (PC=137), or abdominal paraganglioma (PG=17). Twenty had MEN 2 (16 MEN 2A; 4 MEN 2B), 15 von Recklinghausen's disease (VRD), and 1 von Hippel-Lindau (VHL) disease. Twelve patients had, or developed, bilateral adrenal medullary tumors; four with MEN 2A, four with MEN 2B, three with VRD, and one with probably hereditary PC associated with brain tumors/meningioma. Two patients with MEN 2B and one with MEN 2A with had bilateral adrenalectomy (adx). Three VRD patients, two MEN 2B and one MEN 2A patients had cortical-sparing surgery. Two patients were operated on unilaterally, but developed small contralateral tumors; one of these (MEN 2A) had a second asymptomatic PC diagnosed at an older age, so surgery was withheld; the other patient (hereditary PC syndrome) had a small contralateral PC diagnosed at autopsy 9 years later. Only three of nine patients with bilateral operations needed corticosteroid replacement after surgery. Four of six patients died of associated tumors (MTC and meningioma). The mean follow-up was 13 (1-25) years. Twelve MEN 2A patients with unilateral adx have been followed up for 20 (4-36) years without developing a second PC. Cortical-sparing adrenal surgery can safely be performed in the majority of patients with bilateral PC. On the basis of our long-term experience of MEN 2A we perform contralateral adrenal resection only if a second PC is confirmed. Five patients underwent adrenal exploration because of clinical and biochemical findings compatible with PC. Four had asymmetrical positive MIBG scans. They all underwent unilateral adx and diffuse medullary hyperplasia was confirmed (medullary weight estimated morphometrically to 1.0-3.4 g vs. normal weight 0.3-0.5 g in matched controls). These patients have been followed for 19 (5-27) years with normal clinical and biochemical findings. In this rare condition removal of the largest adrenal seems adequate.

Age-related structural characteristics of the adrenal medulla in hypertensive NISAG rats

Structural characteristics of the adrenal medulla in hypertensive NISAG rats (hereditary stress-induced arterial hypertension) were studied during various periods of postnatal ontogeny. Signs of hyperplasia of the adrenal medulla were most pronounced in adult hypertensive animals with persistent arterial hypertension, as well as during the period of late ontogeny.

Morphological Changes in the Atlantic Bottlenose Dolphin (Tursiops truncatus) Adrenal Gland Associated with Chronic Stress

Beach-stranded Atlantic bottlenose dolphins (n=68) were categorized as either "acutely stressed" (if they died from net entanglement, boat strike, or acute infection; 31 animals) or "chronically stressed" (if they suffered from or died as a result of long-term disease or debilitating injury; 37 animals). No significant differences in mass between the right and left adrenal glands were found within each category. However, the average gland mass (AGM), based on the right and left glands together, was 5.2g for acutely stressed animals and 11.01 g for chronically stressed animals (P<0.001). Significant differences were also found, in terms of the ratio of cross-sectional areas of the cortex to medulla, between acutely stressed (ratio 1.22) and chronically stressed (ratio 1.63) animals (P=0.027). Adrenal glands of acutely stressed animals consisted of 48% cortex, 41% medulla, and 11% other tissue elements (connective tissue, blood vessels and gland capsule), whereas the corresponding figures for chronically stressed animals were 53%, 36%, and 11%. The mean estimated mass values for cortex, medulla and other tissue were, for acutely stressed animals, 2.36, 1.9, and 0.54, respectively, whereas for chronically stressed animals the corresponding figures were 6.06, 4.04, and 1.29 (P<0.001 for each of the three comparisons). Overstaining with haematoxylin (HEM) and immunohistochemical labelling (IHC) of the enzyme phenylethanolamine N-methyl transferase (which converts norepinephrine to epinephrine) were used to determine the percentage of epinephrine-producing cells in relation to the overall cross-sectional area of the adrenal gland. The percentage values in acutely as compared with chronically stressed dolphins were 6.7% and 15.93%, respectively (P=0.021). The results therefore suggest that in bottlenose dolphins chronic stress results in increases in (1) adrenal mass, (2) cortex to medulla ratio, and (3) epinephrine-producing cells within the medulla, giving rise to an increase in the thickness of the medullary band.

Chronic stress induces adrenal hyperplasia and hypertrophy in a subregion-specific manner

The adrenal gland is an essential stress-responsive organ that is part of both the hypothalamic-pituitary-adrenal axis and the sympatho-adrenomedullary system. Chronic stress exposure commonly increases adrenal weight, but it is not known to what extent this growth is due to cellular hyperplasia or hypertrophy and whether it is subregion specific. Moreover, it is not clear whether increased production of adrenal glucocorticoid after chronic stress is due to increased sensitivity to adrenocorticotropic hormone (ACTH) vs. increased maximal output. The present studies use a 14-day chronic variable stress (CVS) paradigm in adult male rats to assess the effects of chronic stress on adrenal growth and corticosterone steroidogenesis. Exogenous ACTH administration (0-895 ng/100 g body wt) to dexamethasone-blocked rats demonstrated that CVS increased maximal plasma and adrenal corticosterone responses to ACTH without affecting sensitivity. This enhanced function was associated with increased adrenal weight, DNA and RNA content, and RNA/DNA ratio after CVS, suggesting that both cellular hyperplasia and hypertrophy occurred. Unbiased stereological counting of cells labeled for Ki67 (cell division marker) or 4,6-diamidino-2-phenylindole (nuclear marker), combined with zone specific markers, showed that CVS induced hyperplasia in the outer zona fasciculata, hypertrophy in the inner zona fasciculata and medulla, and reduced cell size in the zona glomerulosa. Collectively, these results demonstrate that increased adrenal weight after CVS is due to hyperplasia and hypertrophy that occur in specific adrenal subregions and is associated with increased maximal corticosterone responses to ACTH. These chronic stress-induced changes in adrenal growth and function may have implications for patients with stress-related disorders.

Maternal perinatal undernutrition alters neuronal and neuroendocrine differentiation in the rat adrenal medulla at weaning

Epidemiological studies suggest that chronic adult diseases, such as type 2 diabetes and hypertension, can be programmed during fetal and early postnatal life. The nervous system regions governing vegetative functions and the hypothalamic-pituitary-adrenal axis are particularly sensitive to the perinatal nutritional status. Despite recent reports demonstrating that the activity of the sympathoadrenal system can be altered by early life events, the effects of maternal nutrient restriction on the adrenal medulla remain unknown. Using a rat model of maternal perinatal 50% food restriction (FR50) from the second week of gestation until weaning, immunohistochemical experiments revealed alterations in chromaffin cell aggregation and in nerve fiber fasciculation in the adrenal medulla of FR50 pups. These morphological changes were associated with enhanced circulating levels of catecholamines after decapitation (epinephrine by 55% and norepinephrine by 41%). Using macroarrays, we identified several genes whose expression was affected by maternal nutrient restriction. Semiquantitative RT-PCR confirmed the overexpression of four genes involved in neuroendocrine differentiation and neuronal plasticity (chromogranin B, growth-associated protein 43, neurofilament 3, and Slit2) in the adrenal glands of FR50 rats. Using in situ hybridization, we showed that these genes are solely expressed in the adrenal medulla. Together, our results suggest that perinatal maternal undernutrition markedly alters the differentiation of the adrenal medulla during postnatal life, resulting in enhanced activity of chromaffin cells at weaning. These alterations may persist in adulthood and participate to the programming of chronic adult diseases.