Cushing's disease: current medical therapies and molecular insights guiding future therapies

Reoperation for Recurrent and Persistent Cushing's Disease without Visible MRI Findings

PURPOSE

Transsphenoidal surgery is the first-line treatment for Cushing's disease (CD), even with negative preoperative magnetic resonance imaging (MRI) results. Some patients with persistent or recurring hypercortisolism have negative MRI findings after the initial surgery. We aimed to analyze the efficacy of repeat surgery in two groups of patients and determine if there is an association between positive MRI findings and early remission.

PATIENTS AND METHODS

Clinical, imaging, and biochemical information of 42 patients who underwent repeat surgery by a single neurosurgeon between 2002 and 2021 was retrospectively analyzed. We compared the endocrinological, histopathological, and surgical outcomes before and after repeat surgery among 14 CD patients with negative MRI findings and 28 patients with positive MRI findings.

RESULTS

Immediate remission was achieved in 29 patients (69.0%) who underwent repeat surgery. Among all patients, 28 (66.7%) had MRI findings consistent with solid lesions. There was no significant difference in remission rates between the recurrence and persistence groups (77.8% vs. 57.1%, odds ratio = 2.625, 95% confidence interval = 0.651 to 10.586). Patients in remission after repeat surgery were not associated with positive MRI findings (odds ratio = 3.667, 95% confidence interval = 0.920 to 14.622).

CONCLUSIONS

In terms of recurrence, repeat surgery in patients with either positive or negative MRI findings showed reasonable remission rates. For persistent disease with positive MRI findings, repeat surgery is still an option; however, more solid evidence is needed to determine if negative MRI findings are predictors for failed reoperations for persistent hypercortisolism.

Correction of Hypercortisolemia with an Improved Cognitive Function and Muscle Mass after Transsphenoidal Surgery in an Older Patient with Cushing's Disease

Cushing's disease causes numerous metabolic disorders, cognitive decline, and sarcopenia, leading to deterioration of the general health in older individuals. Cushing's disease can be treated with transsphenoidal surgery, but thus far, surgery has often been avoided in older patients. We herein report an older woman with Cushing's disease whose cognitive impairment and sarcopenia improved after transsphenoidal surgery. Although cognitive impairment and sarcopenia in most older patients show resistance to treatment, our case indicates that normalization of the cortisol level by transsphenoidal surgery can be effective in improving the cognitive impairment and muscle mass loss caused by Cushing's disease.

Celastrol Induces Apoptosis and Autophagy via the AKT/mTOR Signaling Pathway in the Pituitary ACTH-secreting Adenoma Cells

OBJECTIVE

Pituitary adrenocorticotropic hormone (ACTH)-secreting adenoma is a relatively intractable endocrine adenoma that can cause a range of severe metabolic disorders and pathological changes involving multiple systems. Previous studies have shown that celastrol has antitumor effects on a variety of tumor cells via the AKT/mTOR signaling. However, whether celastrol has pronounced antitumor effects on pituitary ACTH-secreting adenoma is unclear. This study aimed to identify a new effective therapeutic drug for pituitary ACTH-secreting adenoma.

METHODS

Mouse pituitary ACTH-secreting adenoma cells (AtT20 cells) were used as an experimental model in vitro and to establish a xenograft tumor model in mice. Cells and animals were administered doses of celastrol at various levels. The effects of celastrol on cell viability, migration, apoptosis and autophagy were then examined. Finally, the potential involvement of AKT/mTOR signaling in celastrol's mechanism was assessed.

RESULTS

Celastrol inhibited the proliferation and migration of pituitary adenoma cells in a time- and concentration-dependent manner. It blocked AtT20 cells in the G0/G1 phase, and induced apoptosis and autophagy by downregulating the AKT/mTOR signaling pathway. Similar results were obtained in mice.

CONCLUSION

Celastrol exerts potent antitumor effects on ACTH-secreting adenoma by downregulating the AKT/mTOR signaling in vitro and in vivo.

Cushing's Disease Management: Glimpse Into 2051

Major advancements are expected in medicine and healthcare in the 21st century- "Digital Age", mainly due to the application of data technologies and artificial intelligence into healthcare. In this perspective article we share a short story depicting the future Cushings' Disease patient and the postulated diagnostic and management approaches. In the discussion, we explain the advances in recent times which makes this future state plausible. We postulate that endocrinology care will be completely reinvented in the Digital Age.

Hormonal aggressiveness according to the expression of cellular markers in corticotroph adenomas

PURPOSE

The molecular mechanisms underlying tumor growth in Cushing's disease (CD) still remain a challenge. Moreover, clinical manifestations of CD may vary depending on hormonal activity; however, factors involved in the hormonal aggressiveness of adrenocorticotropic hormone (ACTH)-secreting pituitary tumors have not been fully clarified. We investigated the association between the expression of cellular markers regarding pituitary tumor progression and initial or postoperative hormone levels in patients with CD.

METHODS

Tumor tissues from 28 corticotroph adenomas (female 26, male 2, mean age 39.21 ± 10.39 years) were subject to immunohistochemical study using the following antibodies: pituitary tumor-transforming gene 1 (PTTG1), cyclin D1, p16, p27, brahma related-gene 1 (Brg1), and Ki-67. We then analyzed the relationship between each cellular marker expression and hormone levels, including 24 h urinary free cortisol (UFC), plasma ACTH, and serum cortisol.

RESULTS

PTTG1 and Ki-67 were expressed in 100% and 50% of patients, respectively. However, the levels did not reflect initial hormonal activity. The cyclin D1-negative group showed higher serum cortisol levels compared to the cyclin D1-positive group (p = 0.01). The 24 h UFC levels were significantly higher in the p27-negative group than in the p27-positive group (p = 0.04), whereas the Brg1-positive group revealed higher serum cortisol levels than in the Brg1-negative group (p = 0.02).

CONCLUSIONS

Although PTTG1 and Ki-67 play an essential role in developing ACTH-secreting tumors, cyclin D1, p27, and Brg1 may be better biomarkers to determine hormonal aggressiveness of the tumor. Further research is needed to understand the influence of cellular markers on hormonal activity in CD.

Development of two surgical approaches to the pituitary gland in the Horse

BACKGROUND

Current treatment of equine pituitary pars intermedia dysfunction (PPID) requires daily oral medication. Minimally invasive surgical palliation of this condition is appealing as a single treatment to alleviate the clinical signs of disease, dramatically improving the welfare of the horse.

OBJECTIVE

To develop a surgical approach to the equine pituitary gland, for subsequent treatment of PPID.

STUDY DESIGN

A cadaver study to develop methodology and a terminal procedure under anaesthesia in the most promising techniques.

ANIMALS AND METHODS

Four surgical approaches to the pituitary gland were investigated in cadaver animals. A ventral trans-basispheniodal osteotomy and a minimally invasive intravenous approach via the ventral cavernous sinus progressed to live horse trials.

RESULTS

Technical complications prevented the myeloscopic and trans-sphenopalatine sinus techniques from being successful. The ventral basisphenoidal osteotomy was repeatable and has potential if an intra-operative imaging guidance system could be employed. The minimally invasive approach was repeatable, atraumatic and relatively inexpensive.

CONCLUSIONS

A minimally invasive surgical approach to the equine pituitary gland is possible and allows for needle placement within the target tissue. More work is necessary to determine what that treatment might be, but repeatable access to the gland has been obtained, which is a promising step.

CT and MRI of adrenal gland pathologies

Besides ultrasound and nuclear medicine techniques, computed tomography (CT) and magnetic resonance imaging (MRI) are commonly used to examine adrenal lesions in both symptomatic and asymptomatic patients. Some adrenal lesions have characteristic radiological features. If an adrenal nodule is discovered incidentally, determining whether the lesion is benign or malignant is of great importance. According to their biological behavior, lesions can be divided into benign (mainly: adenoma, hyperplasia, pheochromocytoma, cyst, hemorrhage, cystic lymphangioma, myelolipoma, hemangioma, ganglioneuroma, teratoma) and malignant (mainly: metastases, adrenal cortical carcinoma, neuroblastoma, lymphoma) conditions. In this paper, we review CT/MRI findings of common adrenal gland lesions.

New Molecular Targets for Treatment of Cushing's Disease

Despite the best outcomes from trans-sphenoidal surgery, approximately one-third of patients with Cushing's disease will need medical therapy. Current treatments have drawbacks and there is a clear clinical need for new therapies. Recent understanding of molecular pathways leading to excess ACTH secretion has identified key components that may be targeted with the aim to provide novel effective treatment for this devastating disease. These include testicular orphan nuclear receptor 4, heat shock protein 90, and epidermal growth factor receptor. Based on data from preclinical studies, clinical trials are seeking to assess whether targeting these novel pathways can translate into patient benefit.

A review of Cushing's disease treatment by the Department of Neuroendocrinology of the Brazilian Society of Endocrinology and Metabolism

The treatment objectives for a patient with Cushing's disease (CD) are remission of hypercortisolism, adequate management of co-morbidities, restoration of the hypothalamic-pituitary-adrenal axis, preservation of fertility and pituitary function, and improvement of visual defects in cases of macroadenomas with suprasellar extension. Transsphenoidal pituitary surgery is the main treatment option for the majority of cases, even in macroadenomas with low probability of remission. In cases of surgical failure, another subsequent pituitary surgery might be indicated in cases with persistent tumor imaging at post surgical magnetic resonance imaging (MRI) and/or pathology analysis of adrenocorticotropic hormone-positive (ACTH+) positive pituitary adenoma in the first procedure. Medical treatment, radiotherapy and adrenalectomy are the other options when transsphenoidal pituitary surgery fails. There are several options of medical treatment, although cabergoline and ketoconazole are the most commonly used alone or in combination. Novel treatments are also addressed in this review. Different therapeutic approaches are frequently needed on an individual basis, both before and, particularly, after surgery, and they should be individualized. The objective of the present review is to provide the necessary information to achieve a more effective treatment for CD. It is recommended that patients with CD be followed at tertiary care centers with experience in treating this condition.

Pituitary-Directed Therapies for Cushing's Disease

Cushing's disease (CD) is caused by a pituitary corticotroph neuroendocrine tumor inducing uncontrolled hypercortisolism. Transsphenoidal surgery is the first-line treatment in most cases. Nonetheless, some patients will not achieve cure even in expert hands, others may not be surgical candidates and a significant percentage will experience recurrence. Many patients will thus require medical therapy to achieve disease control. Pharmacologic options to treat CD have increased in recent years, with an explosion in knowledge related to pathophysiology at the molecular level. In this review, we focus on medications targeting specifically pituitary adrenocorticotropic hormone-secreting tumors. The only medication in this group approved for the treatment of CD is pasireotide, a somatostatin receptor ligand. Cabergoline and temozolomide may also be used in select cases. Previously studied and abandoned medical options are briefly discussed, and emphasis is made on upcoming medications. Mechanism of action and available data on efficacy and safety of cell cycle inhibitor roscovitine, epidermal growth factor receptor inhibitor gefitinib, retinoic acid, and silibinin, a heat shock protein 90 inhibitor are also presented.

Concurrent hyperadrenocorticism and diabetes mellitus in dogs

Hyperadrenocorticism (HAC) and diabetes mellitus (DM) are two diseases that can occur concurrently in dogs. The objective of this study was to evaluate the coexistence of HAC and DM, and the risk factors involved that could contribute to the development of DM in dogs with HAC. A total of 235 dogs with HAC were studied and, according to their fasting glycemia, they were divided into three groups: <5.6mmol/L, between 5.6 and 10.08mmol/L and >10.08mmol/L. The following parameters were evaluated: age, gender, cause of HAC, body condition, glycemia, total cholesterol, triglycerides, urinary cortisol:creatinin ratio (UCCR) and survival time. A 13.61% concurrence of HAC and DM was observed. Dogs with a fasting glycemia >5.6mmol/L, with dislipemia, with Pituitary-Dependent Hyperadrenocorticism, UCCR >100×10^-6 and non-castrated females showed a higher risk of developing DM. The development of DM in dogs with HAC reduces the survival time.

Psychiatric Symptoms in Patients with Cushing's Syndrome: Prevalence, Diagnosis and Management

Cushing's syndrome (CS) results from chronic exposure to cortisol excess, produced by the adrenal cortex. Hypercortisolism predisposes to psychiatric and neurocognitive disorders, mainly to depression and anxiety disorders. Screening tools to identify psychiatric symptoms are available for clinicians in their daily practice, although a specific diagnosis should be performed by specialists. Even if psychiatric symptoms improve after remission of hypercortisolism, complete recovery may not be achieved. Given the burden of these symptoms, psychiatric or psychological monitoring and treatment should be offered through all phases of CS, with a multidisciplinary approach. The aim of this article is to review data on the prevalence, diagnosis and management of psychiatric symptoms seen in patients with CS and to propose therapeutic approaches that may be followed in clinical practice. The prevalence of different psychiatric disorders has been described in both the active phase and after CS remission. Patients may not talk spontaneously about psychiatric symptoms they present, thus clinicians should ask directly about them. We recommend the use of screening tools in clinical practice to detect and treat these symptoms promptly. Even if reference endocrinologists cannot perform a definite psychiatric diagnosis, it will be important to ask patients directly about the presence of symptoms and refer if necessary to a psychiatrist. Additionally, patient information and educational programmes could be useful to manage psychiatric symptoms and to improve quality of life in patients with CS.

Currently used and investigational drugs for Cushing´s disease

INTRODUCTION

Cushing's disease (CD) is caused by a corticotroph adenoma of the pituitary gland that secretes excess adrenocorticotropic hormone (ACTH) causing increased morbidity and mortality. Surgery is the treatment of choice, but is not always successful. Alternatives include radiotherapy, adrenal surgery, and pharmaceutical therapy. The latter is increasingly gaining momentum due to the recent development of compounds that reduce hypercortisolaemia or its symptoms, acting through different mechanisms. Areas covered: In this article, the authors provide a complete overview of the treatment options for Cushing´s disease, including adrenal-directed, tumor-targeted, and peripheral therapies that are currently used or in development, and discuss their potential advantages and limitations. Expert opinion: Considering the lack of long-term remission in up to half of the patients after surgery, and the delayed response to radiotherapy along with potential side effects, there is a strong need for an effective pharmaceutical treatment. Pasireotide, mifepristone, ketoconazole and metyrapone have been approved by regulatory authorities but their use remains limited due to considerable costs and side effects. Research in this field has focused recently on the improvement of pre-existing drugs and the development of safe new ones. However, few approaches aim at targeting the source of the disease, the ACTH-secreting adenoma.

Anti-metastatic potential of somatostatin analog SOM230: Indirect pharmacological targeting of pancreatic cancer-associated fibroblasts

Pancreatic ductal adenocarcinoma (PDA) shows a rich stroma where cancer-associated fibroblasts (CAFs) represent the major cell type. CAFs are master secretors of proteins with pro-tumor features. CAF targeting remains a promising challenge for PDA, a devastating disease where treatments focusing on cancer cells have failed. We previously introduced a novel pharmacological CAF-targeting approach using the somatostatin analog SOM230 (pasireotide) that inhibits protein synthesis in CAFs, and subsequent chemoprotective features of CAF secretome. Using primary cultures of CAF isolated from human PDA resections, we here report that CAF secretome stimulates in vitro cancer cell survival, migration and invasive features, that are abolished when CAFs are treated with SOM230. Mechanistically, SOM230 inhibitory effect on CAFs depends on the somatostatin receptor subtype sst1 expressed in CAFs but not in non-activated pancreatic fibroblasts, and on protein synthesis shutdown through eiF4E-Binding Protein-1 (4E-BP1) expression decrease. We identify interleukin-6 as a SOM230-inhibited CAF-secreted effector, which stimulates cancer cell features through phosphoinositide 3-kinase activation. In vivo, mice orthotopically co-xenografted with the human pancreatic cancer MiaPaCa-2 cells and CAFs develop pancreatic tumors, on which SOM230 treatment does not inhibit growth but abrogates metastasis. Consistently, CAF secretome stimulates epithelial-to-mesenchymal transition in cancer cells, which is reversed upon CAF treatment with SOM230. Our results highlight a novel promising anti-metastatic potential for SOM230 indirectly targeting pancreatic cancer cell invasion through pharmacological inhibition of stromal CAFs.

Surgical management of adrenocorticotropic hormone-secreting pituitary adenomas

Cushing's disease is defined as hypercortisolemia caused by secretion of adrenocorticotropic hormone from a pituitary adenoma. The diagnosis of Cushing's disease is based on clinical symptoms, laboratory and imaging findings. Once an adrenocorticotropic-hormone-secreting adenoma is found, the standard of care is transsphenoidal adenomectomy. MRI negative microadenomas and large, invasive macroadenomas provide a surgical and clinical challenge and are best handled at high volume centers. Multiple options exist for refractory disease or recurrence, including repeat surgery, radiosurgery and radiotherapy, medical management and bilateral adrenalectomy.