Some patients with type 2 diabetes may benefit from intensive glycaemic and blood pressure control: A post-hoc machine learning analysis of ACCORD trial data

AIM

The action to control cardiovascular risk in diabetes (ACCORD) trial showed a neutral average treatment effect of intensive blood glucose and blood pressure (BP) controls in preventing major adverse cardiovascular events (MACE) in individuals with type 2 diabetes. Yet, treatment effects across patient subgroups have not been well understood. We aimed to identify patient subgroups that might benefit from intensive glucose or BP controls for preventing MACE.

MATERIALS AND METHODS

As a post-hoc analysis of the ACCORD trial, we included 10 251 individuals with type 2 diabetes. We applied causal forest and causal tree models to identify participant characteristics that modify the efficacy of intensive glucose or BP controls from 68 candidate variables (demographics, comorbidities, medications and biomarkers) at the baseline. The exposure was (a) intensive versus standard glucose control [glycated haemoglobin (HbA1c) <6.0% vs. 7.0%-7.9%], and (b) intensive versus standard BP control (systolic BP <120 vs. <140 mmHg). The primary outcome was MACE.

RESULTS

Compared with standard glucose control, intensive one reduced MACE in those with baseline HbA1c <8.5% [relative risk (RR): 0.79, 95% confidence interval (CI): 0.67-0.93] and those with estimated glomerular filtration rate ≥106 ml/min/1.73 m2 (RR: 0.74, 95% CI: 0.55-0.99). Intensive BP control reduced MACE in those with normal high-density lipoprotein levels (women >55 mg/dl, men >45 mg/dl; RR: 0.51, 95% CI: 0.34-0.74). Risk reductions were not significant in other patient subgroups.

CONCLUSIONS

Our findings suggest heterogeneous treatment effects of intensive glucose and BP control and could provide biomarkers for future clinical trials to identify more precise HbA1c and BP treatment goals for individualized medicine.

Management of phaeochromocytoma and paraganglioma in patients with germline SDHB pathogenic variants: an international expert Consensus statement

Adult and paediatric patients with pathogenic variants in the gene encoding succinate dehydrogenase (SDH) subunit B (SDHB) often have locally aggressive, recurrent or metastatic phaeochromocytomas and paragangliomas (PPGLs). Furthermore, SDHB PPGLs have the highest rates of disease-specific morbidity and mortality compared with other hereditary PPGLs. PPGLs with SDHB pathogenic variants are often less differentiated and do not produce substantial amounts of catecholamines (in some patients, they produce only dopamine) compared with other hereditary subtypes, which enables these tumours to grow subclinically for a long time. In addition, SDHB pathogenic variants support tumour growth through high levels of the oncometabolite succinate and other mechanisms related to cancer initiation and progression. As a result, pseudohypoxia and upregulation of genes related to the hypoxia signalling pathway occur, promoting the growth, migration, invasiveness and metastasis of cancer cells. These factors, along with a high rate of metastasis, support early surgical intervention and total resection of PPGLs, regardless of the tumour size. The treatment of metastases is challenging and relies on either local or systemic therapies, or sometimes both. This Consensus statement should help guide clinicians in the diagnosis and management of patients with SDHB PPGLs.

Disordered-to-ordered transitions in assembly factors allow the complex II catalytic subunit to switch binding partners

Complex II (CII) activity controls phenomena that require crosstalk between metabolism and signaling, including neurodegeneration, cancer metabolism, immune activation, and ischemia-reperfusion injury. CII activity can be regulated at the level of assembly, a process that leverages metastable assembly intermediates. The nature of these intermediates and how CII subunits transfer between metastable complexes remains unclear. In this work, we identify metastable species containing the SDHA subunit and its assembly factors, and we assign a preferred temporal sequence of appearance of these species during CII assembly. Structures of two species show that the assembly factors undergo disordered-to-ordered transitions without the appearance of significant secondary structure. The findings identify that intrinsically disordered regions are critical in regulating CII assembly, an observation that has implications for the control of assembly in other biomolecular complexes.

Internal Carotid Artery Aneurysm Disguised as Pituitary Macroadenoma

Hypopituitarism due to an internal carotid artery (ICA) aneurysm is rare. We present a case of hypopituitarism and hyperprolactinemia due to a giant right ICA aneurysm. A 56-year-old woman with a history of primary hypothyroidism presented with fatigue, right-sided headache, and blurred vision. Magnetic resonance (MR) of the brain revealed a sellar mass measuring 3.5 × 2.2 cm involving the right cavernous sinus. Initial neurologic examination was unremarkable, and her biochemical evaluation revealed secondary adrenal insufficiency, central hypogonadism, low serum free thyroxine, and mildly elevated serum prolactin, consistent with stalk effect. Hydrocortisone therapy was started for secondary adrenal insufficiency and her levothyroxine dose was adjusted. The patient was referred to neurosurgery for surgical management of her sellar lesion. Preoperative computed tomography angiography (CTA) of the brain revealed a right ICA aneurysm that contacted the optic chiasm and displaced the pituitary gland. The aneurysm was embolized and diverting stents were placed. Repeat laboratory tests showed resolution of the patient's secondary adrenal insufficiency, normalization of serum prolactin, and an increase in serum gonadotropin concentrations to the postmenopausal range. This case highlights that not all sellar lesions are pituitary adenomas, and CTA should be performed in the evaluation of large cavernous sinus lesions to exclude ICA aneurysm.

Clinical consensus guideline on the management of phaeochromocytoma and paraganglioma in patients harbouring germline SDHD pathogenic variants

Patients with germline SDHD pathogenic variants (encoding succinate dehydrogenase subunit D; ie, paraganglioma 1 syndrome) are predominantly affected by head and neck paragangliomas, which, in almost 20% of patients, might coexist with paragangliomas arising from other locations (eg, adrenal medulla, para-aortic, cardiac or thoracic, and pelvic). Given the higher risk of tumour multifocality and bilaterality for phaeochromocytomas and paragangliomas (PPGLs) because of SDHD pathogenic variants than for their sporadic and other genotypic counterparts, the management of patients with SDHD PPGLs is clinically complex in terms of imaging, treatment, and management options. Furthermore, locally aggressive disease can be discovered at a young age or late in the disease course, which presents challenges in balancing surgical intervention with various medical and radiotherapeutic approaches. The axiom-first, do no harm-should always be considered and an initial period of observation (ie, watchful waiting) is often appropriate to characterise tumour behaviour in patients with these pathogenic variants. These patients should be referred to specialised high-volume medical centres. This consensus guideline aims to help physicians with the clinical decision-making process when caring for patients with SDHD PPGLs.

Metabolomics in paraganglioma: applications and perspectives from genetics to therapy

Metabolites represent the highest layer of biological information. Their diverse chemical nature enables networks of chemical reactions that are critical for maintaining life by providing energy and building blocks. Quantification by targeted and untargeted analytical methods using either mass spectrometry or nuclear magnetic resonance spectroscopy has been applied to pheochromocytoma/paraganglioma (PPGL) with the long-term goal to improve diagnosis and therapy. PPGLs have unique features that provide useful biomarkers and clues for targeted treatments. Firstly, high production rates of catecholamines and metanephrines allow for specific and sensitive detection of the disease in plasma or urine. Secondly, PPGLs are associated with heritable pathogenic variants (PV) in around 40% of cases, many of which occur in genes encoding enzymes, such as succinate dehydrogenase (SDH) and fumarate hydratase (FH). These genetic aberrations lead to overproduction of oncometabolites succinate or fumarate, respectively, and are detectable in tumors and blood. Such metabolic dysregulation can be exploited diagnostically, with the aim to ensure appropriate interpretation of gene variants, especially those with unknown significance, and facilitate early tumor detection through regular patient follow-up. Furthermore, SDHx and FH PV alter cellular pathways, including DNA hypermethylation, hypoxia signaling, redox homeostasis, DNA repair, calcium signaling, kinase cascades, and central carbon metabolism. Pharmacological interventions targeted towards such features have the potential to uncover treatments against metastatic PPGL, around 50% of which are associated with germline PV in SDHx. With the availability of omics technologies for all layers of biological information personalized diagnostics and treatment is in close reach.

Metabolic Characterization and Glyceraldehyde-3-Phosphate Dehydrogenase-Dependent Regulation of Epithelial Sodium Channels in hPheo1 Wild-type and SDHB Knockdown Cells

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors with limited curative treatment options outside of surgical resection. Patients with mutations in succinate dehydrogenase subunit B (SDHB) are at an increased risk of malignant and aggressive disease. As cation channels are associated with tumorigenesis, we studied the expression and activity of cation channels from the Degenerin superfamily in a progenitor cell line derived from a human PCC. hPheo1 wild-type (WT) and SDHB knockdown (KD) cells were studied to investigate whether epithelial sodium channels (ENaC) and acid-sensing ion channels (ASIC) are regulated by the activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). First, we performed targeted metabolomic studies and quantified changes in glycolysis pathway intermediates and citric acid cycle intermediates using hPheo1 WT cells and SDHB KD cells. Next, we performed protein biochemistry and electrophysiology studies to characterize the protein expression and activity, respectively, of these ion channels. Our western blot experiments show both ENaC alpha and ASIC1/2 are expressed in both hPheo1 WT and SDHB KD cells, with lower levels of a cleaved 60 kDa form of ENaC in SDHB KD cells. Single-channel patch clamp studies corroborate these results and further indicate channel activity is decreased in SDHB KD cells. Additional experiments showed a more significant decreased membrane potential in SDHB KD cells, which were sensitive to amiloride compared to WT cells. We provide evidence for the differential expression and activity of ENaC and ASIC hybrid channels in hPheo1 WT and SDHB KD cells, providing an important area of investigation in understanding SDHB-related disease.

PSAT089 Lack of Effect of Metformin in Murine Pheochromocytoma Model

Metformin, a lipophilic biguanide inhibiting hepatic gluconeogenesis and improving peripheral utilization of glucose, is a well-established medication for the management of type 2 diabetes. Furthermore, metformin has been shown to have pleiotropic effects targeting oxidative phosphorylation via complex I inhibition. Thus, it regulates the energy supply to cells from mitochondrial complex I respiration along with reduced glycolytic metabolism. Several pre-clinical in vitro studies on cell lines derived from pheochromocytoma (PHEO) have suggested anti-proliferative potential of metformin which hints that metformin could be used as a potent candidate for PHEO anti-cancer therapy. However, these results have yet to be confirmed in vivo.

Murine PHEO MPC cells and human progenitor hPheo1 cells were treated with metformin in vitro to study the effect on cell proliferation and ATP production. Mice were injected with MTT cells subcutaneously and when the tumors reached the average volume of 120.2±48.1 mm3, they were randomized into 3 groups (n=5) treated with vehicle, 125 mg/kg metformin i.p. daily (6 times a week), or the drug dissolved into drinking water (5 mg/ml). Tumor progression and survival data were collected.

Metformin effectively decreased PHEO cell proliferation and overall ATP production in dose-dependent manner in vitro. Tumor progression was similar in both metformin-treated groups and control group with no significant effect on the growth or mice survival. Even though the metformin showed antiproliferative effects in both murine and human derived cells in vitro, we did not observe tumor growth limitation in our model of murine pheochromocytoma in vivo. However, further studies including newer models and variable treatment conditions including timing, are needed to clarify the lack of efficacy in vivo.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Genetic impairment of succinate metabolism disrupts bioenergetic sensing in adrenal neuroendocrine cancer

Metabolic dysfunction mutations can impair energy sensing and cause cancer. Loss of function of the mitochondrial tricarboxylic acid (TCA) cycle enzyme subunit succinate dehydrogenase B (SDHB) results in various forms of cancer typified by pheochromocytoma (PC). Here we delineate a signaling cascade where the loss of SDHB induces the Warburg effect, triggers dysregulation of [Ca²⁺]_i, and aberrantly activates calpain and protein kinase Cdk5, through conversion of its cofactor from p35 to p25. Consequently, aberrant Cdk5 initiates a phospho-signaling cascade where GSK3 inhibition inactivates energy sensing by AMP kinase through dephosphorylation of the AMP kinase γ subunit, PRKAG2. Overexpression of p25-GFP in mouse adrenal chromaffin cells also elicits this phosphorylation signaling and causes PC. A potent Cdk5 inhibitor, MRT3-007, reverses this phospho-cascade, invoking a senescence-like phenotype. This therapeutic approach halted tumor progression in vivo. Thus, we reveal an important mechanistic feature of metabolic sensing and demonstrate that its dysregulation underlies tumor progression in PC and likely other cancers.

Real-World Experience With Automated Insulin Pump Technology in Veterans With Type 1 Diabetes

Background

Advancements in diabetes technology now allow insulin pump and continuous glucose monitor (CGM) technology to be a part of usual US Department Veterans Affairs (VA) clinical care. The automated insulin pump (AIP) delivers insulin automatically based on CGM readings. In randomized clinical trials the closed-loop system has shown to improve glycemic control in children and younger adults with type 1 diabetes mellitus (T1DM) while preventing hypoglycemia. However, its safety and efficacy is less well known in older veterans with T1DM. In this VA pilot study, we aimed to assess AIP technology in the real world of an older population of veterans with T1DM followed in the outpatient setting.

Methods

Thirty-seven patients with T1DM new to AIP seen at the Malcom Randall VA Medical Center in Gainesville, Florida, were evaluated between March and December of 2018 on an Medtronic Minimed 670G Insulin Pump System. We collected demographic as well as clinical data before and after the initiation of AIP, including standard insulin pump/CGM information (sensor wear, time in target glucose range, time in automated mode, other).

Results

At the time of the initiation of AIP, the mean (SD) age of patients was 59.1 (14.4) years; 35 identified as male and 2 as female. The mean (SD) duration of T1DM was 25.3 (12.0) years. Patients transitioned from either insulin injections or other non-AIP pump to AIP safely-there was no increase in hypoglycemia, and the mean (SD) hemoglobin A_1c decreased from 7.6% (0.8) to 7.3% (0.8) by the second follow-up visit.

Conclusion

In this real-world study, AIP use was both safe and viable as a tool for T1DM management with older veterans. This technology further engaged veterans in monitoring their blood sugars and achieving more optimal glycemic control. Future long-term, larger studies are much needed in this setting.

Case report: Two sisters with a germline CHEK2 variant and distinct endocrine neoplasias

Genetic testing has become the standard of care for many disease states. As a result, physicians treating patients who have tumors often rely on germline genetic testing results for making clinical decisions. Cases of two sisters carrying a germline CHEK2 variant are highlighted whereby possible other genetic drivers were discovered on tumor analysis. CHEK2 (also referred to as CHK2) loss of function has been firmly associated with breast cancer development. In this case report, two siblings with a germline CHEK2 mutation also had distinct endocrine tumors. Pituitary adenoma and pancreatic neuroendocrine tumor (PNET) was found in the first sibling and pheochromocytoma (PCC) discovered in the second sibling. Although pituitary adenomas, PNETs, and PCC have been associated with NF1 gene mutations, the second sister with a PCC did have proven germline CHEK2 with a pathogenic somatic NF1 mutation. We highlight the clinical point that unless the tumor is sequenced, the real driver mutation that is causing the patient's tumor may remain unknown.

Germline SUCLG2 Variants in Patients with Pheochromocytoma and Paraganglioma

BACKGROUND

Pheochromocytoma and paraganglioma (PPGL) are neuroendocrine tumors with frequent mutations in genes linked to the tricarboxylic acid cycle. However, no pathogenic variant has been found to date in succinyl-CoA ligase (SUCL), an enzyme that provides substrate for succinate dehydrogenase (SDH; mitochondrial complex II; CII), a known tumor suppressor in PPGL.

METHODS

A cohort of 352 subjects with apparently sporadic PPGL underwent genetic testing using a panel of 54 genes developed at the National Institutes of Health, including the SUCLG2 subunit of SUCL. Gene deletion, succinate levels, and protein levels were assessed in tumors where possible. To confirm the possible mechanism, we used a progenitor cell line, hPheo1, derived from a human pheochromocytoma, and ablated and re-expressed SUCLG2.

RESULTS

We describe eight germline variants in the GTP-binding domain of SUCLG2 in 15 patients (15 of 352, 4.3%) with apparently sporadic PPGL. Analysis of SUCLG2-mutated tumors and SUCLG2-deficient hPheo1 cells revealed absence of SUCLG2 protein, decrease in the level of the SDHB subunit of CII and faulty assembly of the complex, resulting in aberrant respiration and elevated succinate accumulation.

CONCLUSIONS

Our study suggests SUCLG2 as a novel candidate gene in the genetic landscape of PPGL. Large-scale sequencing may uncover additional cases harboring SUCLG2 variants and provide more detailed information about their prevalence and penetrance.

Expression of Key Androgen-Activating Enzymes in Ovarian Steroid Cell Tumor, Not Otherwise Specified

To characterize the expression of steroidogenic enzymes implicated in the development of ovarian steroid cell tumors, not otherwise specified (SCT-NOS). We present 4 ovarian SCT-NOS evaluated by immunohistochemical staining of steroidogenic enzymes as an approach to define this entity pathologically. All 4 ovarian SCT-NOS showed increased expression for cholesterol side-chain cleavage enzyme (CYP11A1), 17α-hydroxylase (CYP17A1), 17β-hydroxysteroid dehydrogenase 1 (HSD17B1), aldo-ketoreductase type 1 C3 (AKR1C3), 3β-hydroxysteroid dehydrogenase 2 (HSD3B2), 5α-reductase type 2 (SRD5A2), steroid sulfatase (SULT2A1), estrogen sulfotransferase (EST), and aromatase (CYP19A1). Expression was negative for 21-hydroxylase (CYP21A2) and 17β-hydroxysteroid dehydrogenase 2 (HSD17B2). 17β-hydroxysteroid dehydrogenase 3 (HSD17B3) and 5α-reductase type 1 (SRD5A1) showed variable expression. Our analysis reveals a novel finding of increased expression of AKR1C3, HSD17B1, SRD5A2, SULT2A1, and EST in ovarian SCT-NOS, which is clinically associated with androgen excess and virilization. Further studies are needed to validate these enzymes as new markers in the evaluation of hyperandrogenic ovarian conditions.

Extracellular Vesicles From SDHB Deficient hPheo1 Cells Activate STAT3 in Wild-Type Cells

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that originate from the adrenal medulla and extra-adrenal paraganglia, respectively. Inactivating mutations in succinate dehydrogenase (SDHx) genes leads to succinate accumulation, increased HIF1-α levels, and uncontrollable growth of PPGLs. We hypothesized that small extracellular vesicles (EVs) released from progenitor cells derived from pheochromocytoma (hPheo1) with a shRNA mediated knockdown of SDHB are enriched in succinate metabolites that play a key role in the activation of various tyrosine dependent signaling pathways that are involved in turmorigenesis and proliferation. We isolated EVs from the conditioned media of human wild-type hPheo1 cells and hPheo1 cells with shRNA SDHB knockdown. The EVs from three separate preparations of each group were characterized by nanoparticle tracking analysis, transmission electron microscopy, and Western blotting using antibodies against different types of EV and one non-EV marker. Our results show small EVs from the SDHB knockdown hPheo1 cells increased the activation of phosphotyrosine residues in wild-type cells compared to cells treated with control EVs from the same cell type. Additionally, our data show these EVs increase phospho-STAT3 compared to the control EVs (3843.10 +/- 1138.89 vs. 213.65+/- 40.75; p<0.05; n=3) in cultured wild-type hPheo1 cells. Protein tyrosine kinases (PTKs) control various cellular processes including growth, differentiation, and metabolism by activating various signaling pathways including STAT3. The significance of these findings is that in some cancers, elevated succinate from a SDHx mutation has been shown to activate STAT3 which may explain a possible pathway for tumorigenesis. Studies from other investigators have shown that STAT3 expression is elevated in malignant PPGL tissues. Through enriched EV analysis our findings have confirmed the role of STAT3 in SDHB deficient cells. Additional studies are needed to identify other metabolites that are enriched in EVs that regulate phosphorylation of tyrosine residues and STAT3 activation.

Subacute Thyroiditis and Heart Failure in a Patient Presenting With COVID-19

A 67-year-old male was admitted with shortness of breath and diarrhea. His COVID-19 polymerase chain reaction test was positive, and he was found to be in acute heart failure. Troponin levels were elevated, echocardiogram showed ejection fraction of 24%, and his electrocardiogram was normal. Inflammatory markers were elevated. Further testing revealed suppressed thyroid-stimulating hormone and elevated free thyroxine (T4). Differential diagnosis at this point included possible myocarditis from the viral illness, exacerbation of heart failure from the viral infection or from thyrotoxicosis was considered. Patient’s heart failure improved with initiation of heart failure therapies; however, biochemically, his thyroid function tests (TFTs) did not improve, despite empiric methimazole. Thyroid antibody tests were unremarkable. Thyroid ultrasound showed mildly enlarged thyroid gland with no increased vascularity and 5-mm bilateral cysts. Thyroid dysfunction was attributed to subacute thyroiditis from COVID-19, methimazole was tapered, and prednisone was initiated. The patient’s TFTs improved. With the ongoing COVID-19 pandemic, it is imperative that clinicians keep a broad differential in individuals presenting with heart failure, and obtaining baseline TFTs may be reasonable. Rapid treatment of the underlying thyroiditis is important in these patients to improve the cardiovascular outcomes. In our experience, steroid therapy showed a rapid improvement in the TFTs.

Vanishing Adrenal Mass in Pregnancy

Objectives

The evaluation of an adrenal mass is challenging. We present the case of a 33-year-old pregnant woman who was found to have an adrenal incidentaloma. Four months after the initial imaging, the mass vanished.

Methods

We described the case of a pregnant woman with hypertension and an incidentally found right adrenal mass.

Results

A magnetic resonance imaging scan showed a right adrenal mass measuring 7.9 × 3.9 × 3.0 cm with a multilobulated appearance. Initial biochemical testing was concerning for a pheochromocytoma with positive metanephrines during hospitalization while being treated for an infection. Repeat outpatient adrenal hormone results, including metanephrines, were negative. Four months after her initial magnetic resonance imaging scan, the right adrenal mass was no longer present.

Conclusion

A 33-year-old pregnant woman was found to have a right adrenal mass that later vanished as a result of the resolution of a unilateral adrenal hemorrhage. Predisposing factors to adrenal hemorrhage in the presented case include pregnancy, infection, and hypertension.

Succinate Mediates Tumorigenic Effects via Succinate Receptor 1: Potential for New Targeted Treatment Strategies in Succinate Dehydrogenase Deficient Paragangliomas

Paragangliomas and pheochromocytomas (PPGLs) are chromaffin tumors associated with severe catecholamine-induced morbidities. Surgical removal is often curative. However, complete resection may not be an option for patients with succinate dehydrogenase subunit A-D (SDHx) mutations. SDHx mutations are associated with a high risk for multiple recurrent, and metastatic PPGLs. Treatment options in these cases are limited and prognosis is dismal once metastases are present. Identification of new therapeutic targets and candidate drugs is thus urgently needed. Previously, we showed elevated expression of succinate receptor 1 (SUCNR1) in SDHB PPGLs and SDHD head and neck paragangliomas. Its ligand succinate has been reported to accumulate due to SDHx mutations. We thus hypothesize that autocrine stimulation of SUCNR1 plays a role in the pathogenesis of SDHx mutation-derived PPGLs. We confirmed elevated SUCNR1 expression in SDHx PPGLs and after SDHB knockout in progenitor cells derived from a human pheochromocytoma (hPheo1). Succinate significantly increased viability of SUCNR1-transfected PC12 and ERK pathway signaling compared to control cells. Candidate SUCNR1 inhibitors successfully reversed proliferative effects of succinate. Our data reveal an unrecognized oncometabolic function of succinate in SDHx PPGLs, providing a growth advantage via SUCNR1.

HIF2α supports pro-metastatic behavior in pheochromocytomas/paragangliomas

Mutations that drive the stabilization of hypoxia inducible factor 2α (HIF2α) and downstream pseudohypoxic signaling are known to predispose to the development of pheochromocytomas and paragangliomas (PPGLs). However, any role of HIF2α in predisposition to metastatic disease remains unclear. To assess such a role we combined gene-manipulations in pheochromocytoma cell lines with retrospective analyses of patient data and gene expression profiling in tumor specimens. Among 425 patients with PPGLs identified with mutations in tumor-susceptibility genes, those with tumors due to activation of pseudohypoxic pathways had a higher frequency of metastatic disease than those with tumors due to activation of kinase-signaling pathways, even without inclusion of patients with mutations in SDHB (18.6% vs 4.3% in, P < 0.0001). Three out of nine (33%) patients with gain-of-function mutations in HIF2α had metastatic disease. In cell line studies, elevated expression of HIF2α enhanced cell proliferation and led to increased migration and invasion capacity. Moreover, HIF2α expression in HIF2α-deficient cells resulted in increased cell motility, diffuse cluster formation and emergence of pseudopodia indicating changes in cell adhesion and cytoskeletal remodeling. In a mouse liver metastasis model, Hif2a enhanced the metastatic load. Transcriptomics data revealed alterations in focal adhesion and extracellular matrix-receptor interactions in HIF2α-mutated PPGLs. Our translational findings demonstrate that HIF2α supports pro-metastatic behavior in PPGLs, though other factors remain critical for subsequent transition to metastasis. We identified LAMB1 and COL4A2 as new potential therapeutic targets for HIF2α-driven PPGLs. Identified HIF2α downstream targets might open a new therapeutic window for aggressive HIF2α-expressing tumors.

Targeting pheochromocytoma/paraganglioma with polyamine inhibitors

BACKGROUND

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are neuroendocrine tumors that are mostly benign. Metastatic disease does occur in about 10% of cases of PCC and up to 25% of PGL, and for these patients no effective therapies are available. Patients with mutations in the succinate dehydrogenase subunit B (SDHB) gene tend to have metastatic disease. We hypothesized that a down-regulation in the active succinate dehydrogenase B subunit should result in notable changes in cellular metabolic profile and could present a vulnerability point for successful pharmacological targeting.

METHODS

Metabolomic analysis was performed on human hPheo1 cells and shRNA SDHB knockdown hPheo1 (hPheo1 SDHB KD) cells. Additional analysis of 115 human fresh frozen samples was conducted. In vitro studies using N¹,N¹¹-diethylnorspermine (DENSPM) and N¹,N¹²- diethylspermine (DESPM) treatments were carried out. DENSPM efficacy was assessed in human cell line derived mouse xenografts.

RESULTS

Components of the polyamine pathway were elevated in hPheo1 SDHB KD cells compared to wild-type cells. A similar observation was noted in SDHx PCC/PGLs tissues compared to their non-mutated counterparts. Specifically, spermidine, and spermine were significantly elevated in SDHx-mutated PCC/PGLs, with a similar trend in hPheo1 SDHB KD cells. Polyamine pathway inhibitors DENSPM and DESPM effectively inhibited growth of hPheo1 cells in vitro as well in mouse xenografts.

CONCLUSIONS

This study demonstrates overactive polyamine pathway in PCC/PGL with SDHB mutations. Treatment with polyamine pathway inhibitors significantly inhibited hPheo1 cell growth and led to growth suppression in xenograft mice treated with DENSPM. These studies strongly implicate the polyamine pathway in PCC/PGL pathophysiology and provide new foundation for exploring the role for polyamine analogue inhibitors in treating metastatic PCC/PGL. PRéCIS: Cell line metabolomics on hPheo1 cells and PCC/PGL tumor tissue indicate that the polyamine pathway is activated. Polyamine inhibitors in vitro and in vivo demonstrate that polyamine inhibitors are promising for malignant PCC/PGL treatment. However, further research is warranted.

Pheochromocytomas and Paragangliomas

Pheochromocytomas are rare neuroendocrine tumors. Extra-adrenal lesions arising from the autonomic neural ganglia are termed paraganglioma. Clinical symptoms are common between the adrenal and extra-adrenal forms and are determined by excess secretion of catecholamines. Hypertension is a critical and often dramatic feature of pheochromocytoma/paraganglioma, and its most prevalent reported symptom. However, given the rare occurrence of this cancer, in patients undergoing screening for hypertension, the prevalence ranges from 0.1% to 0.6%. Still, patients frequently come to the attention of endocrinologist when pheochromocytoma/paraganglioma is suspected as a secondary cause of hypertension. This article summarizes current clinical approaches in patients with pheochromocytoma/paraganglioma.

Molecular Mechanisms of Primary Aldosteronism

Primary aldosteronism (PA) results from excess production of mineralocorticoid hormone aldosterone by the adrenal cortex. It is normally caused either by unilateral aldosterone-producing adenoma (APA) or by bilateral aldosterone excess as a result of bilateral adrenal hyperplasia. PA is the most common cause of secondary hypertension and associated morbidity and mortality. While most cases of PA are sporadic, an important insight into this debilitating disease has been derived through investigating the familial forms of the disease that affect only a minor fraction of PA patients. The advent of gene expression profiling has shed light on the genes and intracellular signaling pathways that may play a role in the pathogenesis of these tumors. The genetic basis for several forms of familial PA has been uncovered in recent years although the list is likely to expand. Recently, the work from several laboratories provided evidence for the involvement of mammalian target of rapamycin pathway and inflammatory cytokines in APAs; however, their mechanism of action in tumor development and pathophysiology remains to be understood.

Pitfalls in the interpretation of the cosyntropin stimulation test for the diagnosis of adrenal insufficiency

PURPOSE OF REVIEW

Adrenal insufficiency is a rare disease characterized by cortisol deficiency. The evaluation of patients suspected of having adrenal insufficiency can be challenging because of the rarity of the disease and limitations in the biochemical assessment of the cortisol status by either basal or dynamic testing [adrenocorticotropic hormone (ACTH) stimulation test]. Prompt and adequate diagnosis is of paramount importance to avoid adverse outcomes. We aimed to summarize the recent developments in the conduction and interpretation of the ACTH stimulation test for the diagnosis of adrenal insufficiency.

RECENT FINDINGS

The ACTH stimulation test is commonly performed in patients suspected of having adrenal insufficiency when the basal serum cortisol levels are inconclusive. Recent literature has evaluated the impact of technical aspects such as time of the day the test is performed, type of assay and sample source used for cortisol measurement on the clinical value of this test, as well as the feasibility of reliable low dose ACTH testing.

SUMMARY

Clinicians evaluating patients with suspected adrenal insufficiency should take into consideration the clinical presentation (likelihood of adrenal insufficiency before testing) when interpreting the results of the ACTH stimulation test and be aware of clinical and technical factors that can affect cortisol values and diagnostic accuracy of this test.

BMI trajectories and risk of overall and grade-specific prostate cancer: An observational cohort study among men seen for prostatic conditions

Background

Dynamic longitudinal patterns in body mass index (BMI) have been suggested to better predict health outcomes than static measures. Effects of BMI trajectories on prostate cancer (PCa) risk have not been thoroughly explored.

Methods

Cohort data were derived from electronic medical records of patients who were admitted to a tertiary‐care hospital in the Southeastern USA during 1994‐2016. Patients with a history of urologic clinic visit because of any prostatic condition and with repeatedly measured BMI (n = 4857) were included. BMI trajectories prior to PCa diagnosis were assessed using the developmental trajectory analysis method. Cox proportional hazards regression modeling was used to estimate adjusted hazard ratio (aHR) with 95% confidence intervals (CIs) for overall and grade‐specific PCa.

Results

The median age (interquartile range, IQR) of the participants at baseline was 63 (54, 72) years. Over a median follow‐up (IQR) of 8.0 (2.0, 13.0) years, 714 (14.7%, 714/4857) were diagnosed with PCa. Men with growing BMI trajectory progressing from normal weight to overweight/obese had a 76% increased PCa risk (aHR = 1.76; 95% CI: 1.25, 2.48), and men being obese and experiencing progressive weight gain had 3.72‐fold increased PCa risk (aHR = 3.72; 95% CI: 1.60, 8.66), compared to men with persistently normal BMI. The associations were more pronounced for PCa with Gleason score ≥7. No significant association of decreasing BMI trajectory progressing from obese to normal BMI was found with PCa risk.

Conclusions

Progressively body weight gain during middle‐to‐late adulthood was associated with increased PCa risk for both normal weight and overweight men. Further studies are warranted to confirm this finding.

Pheochromocytoma/Paraganglioma: A Poster Child for Cancer Metabolism

CONTEXT

Pheochromocytomas (PCCs) are tumors that are derived from the chromaffin cells of the adrenal medulla. Extra-adrenal PCCs called paragangliomas (PGLs) are derived from the sympathetic and parasympathetic chain ganglia. PCCs secrete catecholamines, which cause hypertension and have adverse cardiovascular consequences as a result of catecholamine excess. PGLs may or may not produce catecholamines depending on their genetic type and anatomical location. The most worrisome aspect of these tumors is their ability to become aggressive and metastasize; there are no known cures for metastasized PGLs.

METHODS

Original articles and reviews indexed in PubMed were identified by querying with specific PCC/PGL- and Krebs cycle pathway-related terms. Additional references were selected through the in-depth analysis of the relevant publications.

RESULTS

We primarily discuss Krebs cycle mutations that can be instrumental in helping investigators identify key biological pathways and molecules that may serve as biomarkers of or treatment targets for PCC/PGL.

CONCLUSION

The mainstay of treatment of patients with PCC/PGLs is surgical. However, the tide may be turning with the discovery of new genes associated with PCC/PGLs that may shed light on oncometabolites used by these tumors.

Small cell lung cancer tumors and preclinical models display heterogeneity of neuroendocrine phenotypes

Background

Small cell lung cancer (SCLC) is a deadly, high grade neuroendocrine (NE) tumor without recognized morphologic heterogeneity. However, over 30 years ago we described a SCLC subtype with "variant" morphology which did not express some NE markers and exhibited more aggressive growth.

Methods

To quantitate NE properties of SCLCs, we developed a 50-gene expression-based NE score that could be applied to human SCLC tumors and cell lines, and genetically engineered mouse (GEM) models. We identified high and low NE subtypes of SCLC in all of our sample types, and characterized their properties.

Results

We found that 16% of human SCLC tumors and 10% of SCLC cell lines were of the low NE subtype, as well as cell lines from the GEM model. High NE SCLC lines grew as non-adherent floating aggregates or spheroids while Low NE lines had morphologic features of the variant subtype and grew as loosely attached cells. While the high NE subtype expressed one of the NE lineage master transcription factors ASCL1 or NEUROD1, together with NKX2-1, the entire range of NE markers, and lacked expression of the neuronal and NE repressor REST, the low NE subtype had lost expression of most NE markers, ASCL1, NEUROD1 and NKX2-1 and expressed REST. The low NE subtype had undergone epithelial mesenchymal transition (EMT) and had activated the Notch, Hippo and TGFβ pathways and MYC oncogene . Importantly, the high and low NE group of SCLC lines had similar gene expression profiles as their SCLC tumor counterparts.

Conclusions

SCLC tumors and cell lines can exhibit distinct inter-tumor heterogeneity with respect to expression of NE features. Loss of NE expression results in major alterations in morphology, growth characteristics, and molecular properties. These findings have major clinical implications as the two subtypes are predicted to have very different responses to targeted therapies.

Expression of Contactin 4 Is Associated With Malignant Behavior in Pheochromocytomas and Paragangliomas

CONTEXT

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine, usually benign, tumors. Currently, the only reliable criterion of malignancy is the presence of metastases.

OBJECTIVE

The aim of this study was to identify genes associated with malignancy in PPGLs.

DESIGN

Transcriptomic profiling was performed on 40 benign and 11 malignant PPGLs. Genes showing a significantly different expression between benign and malignant PPGLs with a ratio ≥4 were confirmed and tested in an independent series by quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemistry was performed for the validated genes on 109 benign and 32 malignant PPGLs. Functional assays were performed with hPheo1 cells.

SETTING

This study was conducted at the Department of Pathology of the Erasmus MC University Medical Center Rotterdam Human Molecular Genetics laboratory of the de Duve Institute, University of Louvain.

PATIENTS

PPGL samples from 179 patients, diagnosed between 1972 and 2015, were included.

MAIN OUTCOME MEASURES

Associations between gene expression and malignancy were tested using supervised clustering approaches.

RESULTS

Ten differentially expressed genes were selected based on messenger RNA (mRNA) expression array data. Contactin 4 (CNTN4) was overexpressed in malignant vs benign tumors [4.62-fold; false discovery rate (FDR), 0.001]. Overexpression at the mRNA level was confirmed using qRT-PCR (2.90-fold, P = 0.02; validation set: 4.26-fold, P = 0.005). Consistent findings were obtained in The Cancer Genome Atlas cohort (2.7-fold; FDR, 0.02). CNTN4 protein was more frequently expressed in malignant than in benign PPGLs by immunohistochemistry (58% vs 17%; P = 0.002). Survival after 7 days of culture under starvation conditions was significantly enhanced in hPheo1 cells transfected with CNTN4 complementary DNA.

CONCLUSION

CNTN4 expression is consistently associated with malignant behavior in PPGLs.

The Yin and Yang Between Plasma Glucose Levels and Cortisol Replacement Therapy in Schmidt's Syndrome

Objective: To illustrate how steroid replacement in adrenal insufficiency can influence the development of hypoglycemia in a patient with type 1 diabetes mellitus (T1D). Methods: We describe the case of a 36-year-old female patient with T1D and Addison's disease (Schmidt's syndrome) on multiple daily insulin injections who presented with recurrent hypoglycemia despite being on physiological replacement doses of hydrocortisone. Results: With the assistance of continuous glucose monitoring technology, a pattern of nocturnal hypoglycemia was clearly identified. The patient was taking her hydrocortisone 15 mg in the morning and 5 mg in the early afternoon. With the short half-life of oral hydrocortisone, the evening decline in plasma cortisol concentration led to an increased susceptibility to recurrent evening and nocturnal hypoglycemia. Hypoglycemic episodes were resolved when her morning hydrocortisone dose was changed and prednisolone was added to a later time in the evening. Conclusion: Patients with Schmidt's syndrome can be susceptible to nocturnal hypoglycemia with inadequate steroid replacement. Identifying patients at risk for hypoglycemia in Schmidt's syndrome provides an opportunity for precision management beyond the manipulation of antihyperglycemic agents.

PRECISION MEDICINE IN ADRENAL DISORDERS: THE NEXT GENERATION

OBJECTIVE

Discuss exciting new research in the area of adrenal disorders that has emerged in the last few years. Advances in genetics, biochemical diagnosis, and imaging modalities that have set new standards for diagnosis and treatment are described.

METHODS

A literature review was conducted on adrenal disorders using PubMed.

RESULTS

We highlight new developments in adrenal diseases from new genes discovered in aldosterone-producing adenomas, cortisol-producing tumors to pheochromocytomas/paragangliomas. In addition, we discuss new information regarding the question of whether nonfunctional adrenal adenomas are really functional or not. In congenital adrenal hyperplasia, emerging steroids that might be helpful in the near future for diagnostic purposes are discussed. New types of imaging are now available to identify endocrine neoplasms to help clinicians find lesions after biochemical confirmation.

CONCLUSION

The tremendous knowledge gained thus far in adrenal diseases sets the stage for not only new precision treatment modalities for individualized care but also for prevention.

ABBREVIATIONS

ACC = adrenal cortical carcinoma; APA = aldosterone-producing adenoma; APCC = aldosterone-producing cell cluster; CAH = congenital adrenal hyperplasia; CT = computed tomography; DOTATATE = [⁶⁸Ga]-DOTA(0)-Tyr(3)-octreotate; FDG = fluorodeoxyglucose; FH = fumarate hydratase; MR = miner-alocorticoid; MDH2 = malate dehydrogenase 2; PCC = pheochromocytoma; PET = positron emission tomography; PGL = paraganglioma; SCS = subclinical cortisol-secreting; SDHB = succinate dehydrogenase subunit B; TCGA = The Cancer Genome Atlas.

Comprehensive Molecular Characterization of Pheochromocytoma and Paraganglioma

We report a comprehensive molecular characterization of pheochromocytomas and paragangliomas (PCCs/PGLs), a rare tumor type. Multi-platform integration revealed that PCCs/PGLs are driven by diverse alterations affecting multiple genes and pathways. Pathogenic germline mutations occurred in eight PCC/PGL susceptibility genes. We identified CSDE1 as a somatically mutated driver gene, complementing four known drivers (HRAS, RET, EPAS1, and NF1). We also discovered fusion genes in PCCs/PGLs, involving MAML3, BRAF, NGFR, and NF1. Integrated analysis classified PCCs/PGLs into four molecularly defined groups: a kinase signaling subtype, a pseudohypoxia subtype, a Wnt-altered subtype, driven by MAML3 and CSDE1, and a cortical admixture subtype. Correlates of metastatic PCCs/PGLs included the MAML3 fusion gene. This integrated molecular characterization provides a comprehensive foundation for developing PCC/PGL precision medicine.

Delayed Imaging Presentation of a Symptomatic Insulinoma After Bariatric Surgery

Many reports exist on hyperinsulinemic hypoglycemia after bariatric surgery, which can result in persistence of the metabolic syndrome in patients who have undergone these procedures. While the noninsulinoma pancreatogenous hypoglycemia syndrome, or nesidioblastosis, has garnered increased attention in these patients, its presentation is similar to patients with an insulinoma and this entity must therefore be evaluated and ruled out. Herein, we present a patient who developed symptoms of hypoglycemia 7 years after Roux-en-Y gastric bypass surgery. While a diagnosis of insulinoma was entertained, his laboratory values were indeterminate and imaging localization was inconclusive. Because of significant medical comorbidities, he was managed symptomatically until imaging ultimately localized a lesion in the pancreatic uncinate process consistent with an insulinoma. He subsequently underwent resection and remains disease and symptom free 1 year after surgery. This case demonstrates the diagnostic and imaging dilemma in patients with hypoglycemia after bariatric surgery and should be of interest to anyone who cares for these patients.

AN AGGRESSIVE TEMPORAL BONE SDHC PARAGANGLIOMA ASSOCIATED WITH INCREASED HIF-2α SIGNALING

OBJECTIVE

To describe a patient with a germline succinate dehydrogenase (SDHC) gene mutation presenting with primary hyperparathyroidism and a large catecholamine-producing temporal bone paraganglioma (PGL).

METHODS

Evaluation of a SDHC mutation-positive PGL tumor biology using staining for tyrosine hydroxylase (TH), hypoxia-inducible factors 1α (HIF-1α) and 2α (HIF-2α).

RESULTS

A 66-year-old man was noted to have a lytic skull base mass during work-up for his primary hyperparathyroidism. Biochemical evaluation with 24-hour urine catecholamines and metanephrines revealed marked elevation of norepinephrine and normetanephrine. Genetic testing revealed a germline SDHC mutation. A partial excision of skull base tumor was performed, which upon further examination revealed PGL. Immunohistochemistry of skull base PGL demonstrated heavy expression of TH and HIF-2α but reduced expression of HIF-1α. The remaining skull base PGL was treated with adjuvant radiation therapy. The patient's normetanephrine levels significantly decreased after surgery and radiation.

CONCLUSION

Here, we report an unusual case of a patient presenting with a germline SDHC mutation-related functional PGL along with concomitant primary hyperparathyroidism. The present case illustrates that overexpression of HIF-2α but not of HIF-1α is linked to the pathogenesis of SDHC mutation-related PGL, and it may be responsible for the aggressive clinical behavior of a usually indolent course of SDHC-related PGLs.

Benign adrenal adenomas secreting excess mineralocorticoids and glucocorticoids

OBJECTIVE

To recognize that benign adrenal adenomas can co-secrete excess aldosterone and cortisol, which can change clinical management.

METHODS

We reviewed the clinical and histological features of an adrenal tumor co-secreting aldosterone and cortisol in a patient. Biochemical testing as well as postoperative immunohistochemistry was carried out on tissue samples for assessing enzymes involved in steroidogenesis.

RESULTS

A patient presented with hypertension, hypokalemia, and symptoms related to hypercortisolism. The case demonstrated suppressed renin concentrations with an elevated aldosterone:renin ratio, abnormal dexamethasone suppression test results, and elevated midnight salivary cortisol concentrations. The patient had a right adrenal nodule with autonomous cortisol production and interval growth. Right adrenalectomy was carried out. Postoperatively, the patient tolerated the surgery, but he was placed on a short course of steroid replacement given a subnormal postoperative serum cortisol concentration. Long-term follow-up of the patient showed that his blood pressure and glucose levels had improved. Histopathology slides showed positive staining for 3β-hydroxysteroid dehydrogenase, 11β-hydroxylase, and 21 hydroxylase.

CONCLUSION

In addition to the clinical manifestations and laboratory values, the presence of these enzymes in this type of tumor provides support that the tumor in this patient was able to produce mineralocorticoids and glucocorticoids. The recognition of patients with a tumor that is co-secreting aldosterone and cortisol can affect decisions to treat with glucocorticoids perioperatively to avoid adrenal crisis.

LEARNING POINTS

Recognition of the presence of adrenal adenomas co-secreting mineralocorticoids and glucocorticoids.Consideration for perioperative and postoperative glucocorticoid use in the treatment of co-secreting adrenal adenomas.

Phospho-mTOR is not upregulated in metastatic SDHB paragangliomas

BACKGROUND

Pheochromocytomas (PCCs)/paragangliomas (PGLs) are neuroendocrine tumours that may cause arrhythmia and death if untreated. Treatment for patients with metastatic tumours is lacking. As new PCC/PGL susceptibility genes are discovered that are associated with the mTOR pathway, treatment targets focusing on this pathway are being intensively explored.

DESIGN

Twenty-one human PCC/PGLs were analysed from two tertiary care centres. Immunohistochemistry (IHC) analysis was performed for phospho-mTOR (pmTOR), phospho-S6K (pS6K), phosphoinositide 3-kinase (PI3K), phospho-4EBP1 (p4EBP1), HIF1α and MIB-1 in 6 metastatic SDHB PCC/PGLs, 15 nonmetastatic PCC/PGLs, (including 1 TMEM127 PCC and 1 nonmetastatic SDHB PGL) and 6 normal adrenal medullas. The product of the intensity of stain and percentage of cells stained was calculated as an H score.

RESULTS

Using a two-sample t-test and paired t-test, pmTOR and pS6K had significantly higher H scores in nonmetastatic PCC/PGLs than in metastatic SDHB PCC/PGLs. HIF1α had significantly higher H scores in metastatic SDHB PCC/PGLs compared with nonmetastatic PCC/PGLs and normal adrenal medulla. No difference in H scores was seen with p4EBP1, PI3K and MIB-1 when comparing metastatic SDHB PCC/PGLs and nonmetastatic PCC/PGLs. Significantly higher difference in pS6K was seen in normal adrenal medullas compared to nonmetastatic PCC/PGLs and metastatic SDHB PCC/PGLs.

CONCLUSION

The present results suggest that the use of mTOR inhibitors alone for metastatic SDHB PCC/PGLs may not achieve good therapeutic efficacy in patients.

Indexing severity of diabetic foot infection with 99mTc-WBC SPECT/CT hybrid imaging

OBJECTIVE

Management of diabetic foot infection (DFI) has been hampered by limited means of accurately classifying disease severity. New hybrid nuclear/computed tomography (CT) imaging techniques elucidate a combination of wound infection parameters not previously evaluated as outcome prognosticators. Our aim is to determine if a novel standardized hybrid image-based scoring system, Composite Severity Index (CSI), has prognostic value in DFI.

RESEARCH DESIGN AND METHODS

Masked retrospective (99m)Tc-white blood cell (WBC) single photon emission CT (SPECT)/CT image interpretation and independent chart review of 77 patients (101 feet) suspected of DFI-associated osteomyelitis at a large municipal hospital between January 2007 and July 2009. CSI scores were correlated with probability of favorable outcome (no subsequent amputation/readmission after therapeutic intervention) during median 342-day follow-up.

RESULTS

CSI ranged from 0-13. Receiver operating characteristic accuracy for predicting favorable outcome was 0.79 (optimal cutoff CSI, ≤2; odds ratio of therapeutic failure for CSI >2, 15.1 [95% CI 4.4-51.5]). CSI of 0 had a 92% chance of favorable outcome, which fell progressively to 25% as indices rose to ≥7. Image-based osteomyelitis versus no osteomyelitis assessment was less accurate than CSI at predicting outcome (P = 0.016). In patients with intermediate severity (CSI 3-6), treatment failure decreased from 68 to 36% when antibiotic duration was extended to ≥42 days (P = 0.026).

CONCLUSIONS

(99m)Tc-WBC SPECT/CT hybrid image-derived wound infection parameters incorporated into a standardized scoring system, CSI, has prognostic value in DFI.

Effect of KCNJ5 mutations on gene expression in aldosterone-producing adenomas and adrenocortical cells

CONTEXT

Primary aldosteronism is a heterogeneous disease that includes both sporadic and familial forms. A point mutation in the KCNJ5 gene is responsible for familial hyperaldosteronism type III. Somatic mutations in KCNJ5 also occur in sporadic aldosterone producing adenomas (APA).

OBJECTIVE

The objective of the study was to define the effect of the KCNJ5 mutations on gene expression and aldosterone production using APA tissue and human adrenocortical cells.

METHODS

A microarray analysis was used to compare the transcriptome profiles of female-derived APA samples with and without KCNJ5 mutations and HAC15 adrenal cells overexpressing either mutated or wild-type KCNJ5. Real-time PCR validated a set of differentially expressed genes. Immunohistochemical staining localized the KCNJ5 expression in normal adrenals and APA.

RESULTS

We report a 38% (18 of 47) prevalence of KCNJ5 mutations in APA. KCNJ5 immunostaining was highest in the zona glomerulosa of NA and heterogeneous in APA tissue, and KCNJ5 mRNA was 4-fold higher in APA compared with normal adrenals (P < 0.05). APA with and without KCNJ5 mutations displayed slightly different gene expression patterns, notably the aldosterone synthase gene (CYP11B2) was more highly expressed in APA with KCNJ5 mutations. Overexpression of KCNJ5 mutations in HAC15 increased aldosterone production and altered expression of 36 genes by greater than 2.5-fold (P < 0.05). Real-time PCR confirmed increases in CYP11B2 and its transcriptional regulator, NR4A2.

CONCLUSIONS

KCNJ5 mutations are prevalent in APA, and our data suggest that these mutations increase expression of CYP11B2 and NR4A2, thus increasing aldosterone production.

Clinical, biochemical, and molecular characterization of macronodular adrenocortical hyperplasia of the zona reticularis: a new syndrome

CONTEXT

Macronodular adrenocortical hyperplasia classically presents with progressive hypercortisolemia and Cushing syndrome. We describe a 29-yr-old man with massive macronodular adrenocortical hyperplasia without hypercortisolemia but rather markedly elevated and nonsuppressible production of dehydroepiandrosterone (DHEA) and its sulfate (DHEAS).

OBJECTIVE

To characterize the clinical and molecular features of this case and to determine whether the tissue biochemically resembles the zona reticularis or fetal adrenal.

SETTING

University clinic, hospital, and laboratories.

DESIGN

Static and dynamic blood and urine testing were performed preoperatively. Tissue was studied by light microscopy, immunoblot, RNA microarray, and enzyme assay.

PARTICIPANT

A 29-yr-old man with incidentally discovered bilateral adrenal enlargement.

INTERVENTION

Bilateral adrenalectomy.

MAIN OUTCOME MEASURES

Molecular studies compared with control samples.

RESULTS

Hypercortisolism and 21-hydroxylase deficiency were excluded. DHEA, DHEAS, and 17-hydroxypregnenolone were markedly elevated and did not suppress with dexamethasone 2 mg/d for 4 d. Homogenates of the adrenals demonstrated high 17-hydroxylase, good 17,20-lyase, and low or absent 21-hydroxylase and 3β-hydroxysteroid dehydrogenase activities. Immunoblots confirmed robust expression of cytochrome P450c17 and AKR1C3 but not P450c21. Microarray analysis demonstrated high CYP11A1 and CYP17A1 expression but low or absent HSD3B1, HSD3B2, and CYP21A2 expression. Expression of mRNA for cytochrome b(5) (CYB5A) and AKR1C3, markers of the zona reticularis, were markedly elevated.

CONCLUSION

This is the first case of macronodular hyperplasia of the adrenal zona reticularis confirmed with studies of enzyme activity, mRNA expression, and protein identification. We speculate that this condition can be clinically silent in men but might cause severe hyperandrogenemia in women.

The peroxisome proliferator-activated receptor-gamma agonist rosiglitazone increases bone resorption in women with type 2 diabetes: a randomized, controlled trial

In previous studies, with up to 16 weeks of exposure to rosiglitazone or pioglitazone, circulating markers of bone formation [procollagen I N-terminal propeptide (P1NP), osteocalcin, and bone-specific alkaline phosphatase] decreased but no change in bone resorption markers was found. We examined the effect of rosiglitazone on bone resorption and formation markers when used for 24 weeks. This post-hoc analysis of a double-blind, placebo-controlled, randomized trial evaluated the effects of 6 months of rosiglitazone use versus placebo on circulating markers of bone turnover in 111 patients with type 2 diabetes and cardiovascular disease or additional cardiac risk factors. The principal end points for analysis were changes in bone formation and resorption markers, measured by P1NP and carboxy-terminal cross-links (CTX), respectively. There were 111 subjects who completed the study and had baseline and 6-month data; mean age was 56, including 41% women and 67% nonwhite (50 black, 18 Hispanic, and six other), and subjects were evenly distributed between placebo and rosiglitazone groups. Women treated with rosiglitazone had higher CTX levels (0.43 ng/mL) than those who received placebo (0.23 ng/mL) (P = 0.007), with no significant differences in P1NP or OPG. Overall, in stratified analyses of men and in stratified analyses among different ethnicities, there were no statistically significant differences observed in CTX, P1NP, OPG, PTH, or 25-OHD between the treatment groups. Women taking rosiglitazone had higher circulating markers of bone resorption, which is contrary to prior studies of shorter duration, where the principal observation was a decrease in markers of bone formation.

Mediastinal paragangliomas: association with mutations in the succinate dehydrogenase genes and aggressive behavior

Extra-adrenal pheochromocytomas, otherwise known as paragangliomas (PGLs), account for about 20% of catecholamine-producing tumors. Catecholamine excess and mutations in the genes encoding succinate dehydrogenase subunits (SDHx) are frequently found in patients with PGLs. Only 2% of PGLs are found in the mediastinum, and little is known about genetic alterations in patients with mediastinal PGLs, catecholamine production by these tumors, or their clinical behavior. We hypothesized that most mediastinal PGLs are associated with germ line SDHx mutations, norepinephrine and/or dopamine excess, and aggressive behavior. The objective of this study was to characterize genetic, biochemical, and clinical data in a series of ten patients with mediastinal PGLs. All ten primary mediastinal PGL patients had germ line SDHx mutations, six in SDHB, and four in SDHD genes. Chest or back pain were the most common presenting symptoms (five patients), and catecholamines and/or their metabolites were elevated in seven patients. Additional tumors included head and neck PGLs in four patients, pheochromocytoma in one patient, and bladder PGL in another. Metastatic disease was documented in six patients (60%), and a concurrent abdominal mass was found in one patient. We conclude that mediastinal PGLs are strongly associated with SDHB and SDHD gene mutations, noradrenergic phenotype, and aggressive behavior. The present data suggest that all patients with mediastinal PGLs should be screened for SDHx gene mutations, regardless of age.

The many faces of pheochromocytoma

OBJECTIVE

To recognize and manage pheochromocytomas in unusual settings.

METHODS

Three case reports are presented with clinical, biochemical, imaging, and operative findings. The pitfalls in diagnosis of pheochromocytomas and management are addressed.

RESULTS

We begin with a 27-yr-old gravida 2, para 1 Caucasian woman with unexplained tachycardia and hypertension during a routine pre-natal visit at 30 weeks estimated gestational age. Urinary studies revealed elevated catecholamines. Magnetic resonance imaging localized a 6.6-cm right adrenal mass with features consistent with a pheochromocytoma. She was medically managed with phenoxybenzamine and propranolol until 35 weeks, after which she underwent a combined Cesarean section, and open right adrenalectomy. Another patient, a 36-yr-old African-American woman presented to a hospital in cardiac arrest, with elevated serum troponins, and underwent cardiac catheterization, which revealed normal coronary arteries. A computed tomography (CT) scan revealed a left adrenal mass and CT-guided biopsy was consistent with a pheochromocytoma, although prior studies were negative. Finally, we present a 49-yr-old Caucasian woman who had a right adrenalectomy 10 yr prior and presented to the clinic with fluctuating blood pressures, headaches, and palpitations. Further testing revealed she had a recurrent metastatic pheochromocytoma. The challenges behind treating these patients are further explored.

CONCLUSION

Antenatal diagnosis of pheochromocytoma, though challenging, is associated with lower maternal and fetal morbidity and mortality. The differential diagnosis for cardiac arrest in the presence of normal coronary arteries should include a pheochromocytoma. Finally, treatment with iodinated metaiodobenzylguanidine may be a therapeutic option for those patients with metastatic pheochromocytomas.

Hyperthyroidism-associated coronary vasospasm with myocardial infarction and subsequent euthyroid angina

A 40-year-old African-American woman presented with atypical chest pain, an acute non-ST segment elevation myocardial infarction, and angiographic evidence for severe ostial vasospasm of the left main and right coronary arteries. Subsequently, she was diagnosed with hyperthyroidism and treated with antithyroid therapy and oral nitrates. Repeat angiography revealed resolution of the vasospasm; however, the chest pain recurred in the euthyroid state. Hyperthyroidism-associated coronary vasospasm is a rare disorder that characteristically causes angina in young Asian women and resolves with correction of hyperthyroidism. We present an atypical case of an African-American woman presenting with a myocardial infarction who developed recurrent angina while euthyroid.

Clinical implications of androgen synthesis via 5alpha-reduced precursors

During embryogenesis, the male external genitalia are formed by the action of the potent androgen, dihydrotestosterone (DHT). DHT is produced in human genital skin and prostate from testosterone via the action of 5alpha-reductase type 2. The biological relevance of this pathway to DHT is evidenced by patients with mutations in the gene encoding 5alpha-reductase type 2, which causes severely undermasculinized external genitalia in genetic males. In contrast, this paradigm of androgen physiology does not explain some clinical observations, such as the differences noted in the virilization of females with various congenital adrenal hyperplasias. An alternate pathway to DHT was elucidated in the tammar wallaby pouch young, and studies in knockout mice showed that this pathway uses 5alpha-reductase type 1 to convert 17-hydroxyprogesterone to 5alpha-reduced androgen precursors. Flux via the alternate or 'backdoor' pathway has been implicated in human diseases such as P450 oxidoreductase deficiency, polycystic ovarian disease, and congenital adrenal hyperplasia. A better understanding of the 5alpha-reduced or 'backdoor'pathway to DHT in human disorders of androgen excess will provide pharmacotherapy opportunities to effectively treat androgen excess in females.

Basic concepts and recent developments in human steroid hormone biosynthesis

The biosynthesis of steroid hormones requires the coordinated expression of the enzymes that comprise the pathways via which specific hormones are synthesized. These pathways and their associated enzymes are typically subject to regulation consisting of trophic hormone stimuli and feedback mechanisms. Very few tissues contribute substantially to de novo steroidogenesis, primarily the adrenal glands, the gonads, and the placenta. Both the embryonic origins and the signaling mechanisms for the adrenals and gonads are similar, and steroid synthesis in these two glands are the major focus of this review. We will further describe peripheral steroid metabolism and the regulation of steroid hormone potency in target tissues. In addition, we will briefly discuss the congenital adrenal hyperplasias to illustrate the principles developed in the initial sections. Finally, we will discuss some recent developments in steroidogensis, focusing on cytochrome P450 oxidoreductase deficiency and the alternate or "backdoor" pathway to dihydrotestosterone. We will conclude with a description of aberrant signaling mechanisms observed in adrenal tumors as a further example of how these pathways can be disturbed in pathologic states.