Expression and effect of transforming growth factor-alpha and tumor necrosis factor-alpha in human pheochromocytoma

Elevated IL-6 levels in a patient with pheochromocytoma

Pheochromocytoma is a chromaffin cell-derived adrenal medullary tumour and usually presents with paroxysms of hypertension, palpitations, sweating and headache due to excessive catecholamine release. These tumours can also secrete a variety of bioactive neuropeptides and hormones other than catecholamines, resulting in unusual clinical manifestations. We report a female in her mid-30s who presented with fever, anaemia, thrombocytosis and markedly elevated inflammatory markers. The fever profile, including cultures, was negative. Contrast-enhanced CT of abdomen showed a large solid-cystic right adrenal lesion with elevated plasma-free normetanephrine levels suggestive of pheochromocytoma. The fever persisted despite empirical antibiotics and antipyretics. Interleukin-6 (IL-6) levels were elevated (41.2 pg/mL (3-4 pg/mL)). She was initiated on naproxen (NPX) at a dose of 250 mg two times per day. The patient responded to NPX, and after stabilisation, she underwent an adrenalectomy. There was a complete resolution of fever with normalisation of IL-6 levels postoperatively.

IL-6-Producing, Noncatecholamines Secreting Pheochromocytoma Presenting as Fever of Unknown Origin

Fever of unknown origin (FUO) can be an unusual first clinical manifestation of pheochromocytoma. Pheochromocytomas are tumors that may produce a variety of substances in addition to catecholamines. To date, several cases of IL-6-producing pheochromocytomas have been reported. This report describes a 45-year-old woman with pheochromocytoma who was admitted with FUO, normal blood pressure levels, microcytic and hypochromic anemia, thrombocytosis, hyperfibrinogenemia, hypoalbuminemia, and normal levels of urine and plasma metanephrines. After adrenalectomy, fever and all inflammatory findings disappeared.

The Roles of PI3K/AKT/mTOR and MAPK/ERK Signaling Pathways in Human Pheochromocytomas

Objectives. The roles of PI3K/AKT/mTOR and MAPK/ERK pathways involved in the pathogenesis of pheochromocytoma and paraganglioma (PPGL) were demonstrated mostly by in vitro studies with rat or mouse cells and were mainly studied at transcriptional level. This study aimed to investigate the effect of these pathways on the proliferation of human PPGL cells and the activation of these pathways in PPGLs. Methods. Human PPGL cells were treated with sunitinib and inhibitors of PI3K (LY294002), MEK1/2 (U0126), and mTORC1/2 (AZD8055). Cell proliferation was detected by MTT assay. Protein phosphorylation was detected by Western blotting. Results. In most PPGLs, AKT, ERK1/2, and mTOR were activated. LY294002 (10 μM), U0126 (10 μM), AZD8055 (1 μM), and sunitinib (1 μM) inhibited PPGL cell proliferation in ten primary cultures of tissues, including four from patients with gene mutations. MEK1/2 inhibitor decreased mTOR phosphorylation. Inhibition of mTOR reduced phosphorylation of AKT and ERK1/2. Sunitinib inhibited phospho-ERK1/2 and phospho-mTOR. Conclusion. Our study suggested that PI3K/AKT/mTOR and MAPK/ERK signaling pathways play vital roles in human PPGL and are activated in most PPGLs. Inhibiting multiple pathways might be a novel therapeutic approach for PPGLs.

Changes in energy metabolism in pheochromocytoma

CONTEXT

Catecholamine overproduction in pheochromocytoma affects basal metabolism, resulting in weight loss despite normal food intake.

OBJECTIVE

The objective of the study was to evaluate changes in energy metabolism expressed as resting energy expenditure (REE) in patients with pheochromocytoma before and after adrenalectomy and the possible relationship with circulating inflammatory markers.

DESIGN

We measured REE in 17 patients (8 women) with pheochromocytoma by indirect calorimetry (Vmax-Encore 29N system) before and 1 year after adrenalectomy. Body fat percentage was measured with a Bodystat device. Inflammatory markers (leukocytes count and C-reactive protein) and cytokines (TNF-α, IL-6, and IL-8) were analyzed with a Luminex 200.

RESULTS

REE measured in the pheochromocytoma group was 10.4% higher than the predicted value (1731 ± 314 vs 1581 ± 271 kcal/d; P = .004). Adrenalectomy significantly increased body mass index (P =0.004) and the percentage of body fat (P = .01), with a proportional increase in fat distribution (waist circumference, P = .045; hip circumference, P = .001). REE significantly decreased after adrenalectomy (1731 ± 314 vs 1539 ± 215 kcal/d; P = .002), even after adjustments in body surface and body weight (P < .001). After adrenalectomy, we found a significant decrease in leukocyte counts (P = .014) and in the levels of TNF-α (P < .001), IL-6 (P = .048), and IL-8 (P = .007) but not C-reactive protein (P = .09). No significant correlations among calorimetry parameters, hormones, and proinflammatory markers were detected.

CONCLUSIONS

Chronic catecholamine overproduction in pheochromocytoma may lead to a proinflammatory and hypermetabolic state characterized by increased REE. Adrenalectomy leads to the normalization of energy metabolism followed by an increase in body mass index and body fat content and decreases in inflammatory markers and cytokines.