Pheochromocytoma With Adrenergic Biochemical Phenotype Shows Decreased GLP-1 Secretion and Impaired Glucose Tolerance

Neuroendocrine tumors and diabetes mellitus: which treatment and which effect

Diabetes mellitus (DM) and neuroendocrine tumors (NET) can exert unfavorable effects on each other prognosis. In this narrative review, we evaluated the effects of NET therapies on glycemic control and DM management and the effects of anti-diabetic therapies on NET outcome and management. For this purpose, we searched the PubMed, Science Direct, and Google Scholar databases for studies reporting the effects of NET therapy on DM as well as the effect of DM therapy on NET. The majority of NET treatments appear to impair glycaemic control, both inducing hypoglycemic or, more commonly, hyperglycemia and even new-onset DM. However, glucose metabolism imbalance can be effectively managed by modulating anti-diabetic therapy and adopting an appropriate nutritional approach. On the other hand, the effects of anti-diabetic treatment, like insulin, sulfonylureas, thiazolidinediones, ipeptidyl-peptidase-4 inhibitors, Glucagon-like peptide-1 receptor agonists, and Sodium-glucose cotransporter-2 inhibitors on NET are unclear. Recently, metformin has been investigated in patients with gastroenteropancreatic NET resulting in improved progression free survival suggesting a potential antineoplastic role. Finally, the management of DM in patients with NET is of great clinical relevance to correctly perform radiological procedures and even more functional imaging procedures, as well as to optimize the therapy and avoid treatment withdrawal or discontinuation. In conclusion, understanding the mechanisms underlying therapy-induced DM and implementing appropriate monitoring and management strategies of DM are essential for optimizing NET patient outcome and quality of life.

Robot-assisted versus laparoscopic pheochromocytoma resection and construction of a nomogram to predict perioperative hemodynamic instability

BACKGROUND

Despite recent improvements in perioperative outcomes after pheochromocytoma resection, hemodynamic instability (HI) remained of high concern. The emergence of robot-assisted surgery may bring different results to pheochromocytoma surgery. The purposes of this study were to investigate whether robot-assisted retroperitoneal pheochromocytoma resection promotes hemodynamic instability compared with laparoscopic retroperitoneal pheochromocytoma resection and construct a nomogram to predict perioperative hemodynamic instability.

METHODS

The clinical data of 221 patients who underwent pheochromocytoma resection were analyzed retrospectively. The patients were divided into two groups according to the mode of operation. Stepwise logistic regression was used to determine the independent risk factors of perioperative hemodynamic instability and to construct a visual prediction model. The final model was visualized via a nomogram.

RESULTS

124 (56.1 %) out of 221 patients experienced HI. The variables that were eventually included in the model were tumor size (OR1.363(1.143-1.646), P < 0.001), abnormal blood glucose (OR3.381(1.534-7.903), P = 0.003), preoperative SBP(OR1.04(1.014-1.067),P = 0.002), robot-assisted surgery(OR0.241(0.108-0.513),P < 0.001), and catecholamines(OR4.567(2.424-8.834),P < 0.001). The receiver operating characteristic curve showed the area under curve was 0.816(95 %CI 0.761-0.871).

CONCLUSION

We developed a nomogram for successful prediction of perioperative hemodynamics based on five independent risk factors. Clinicians can leverage this easy-to-use nomogram to perform personalized risk predictions for HI and develop preventive interventions to improve patient safety and surgical outcomes.

Practical therapeutic approach in the management of diabetes mellitus secondary to Cushing's syndrome, acromegaly and neuroendocrine tumours

Cushing's syndrome, acromegaly and neuroendocrine disorders are characterized by an excess of counterregulatory hormones, able to induce insulin resistance and glucose metabolism disorders at variable degrees and requiring immediate treatment, until patients are ready to undergo surgery. This review focuses on the management of diabetes mellitus in endocrine disorders related to an excess of counterregulatory hormones. Currently, the landscape of approved agents for treatment of diabetes is dynamic and is mainly patient-centred and not glycaemia-centred. In addition, personalized medicine is more and more required to provide a precise approach to the patient's disease. For this reason, we aimed to define a practical therapeutic algorithm for management of diabetes mellitus in patients with glucagonoma, pheochromocytoma, Cushing's syndrome and acromegaly, based on our practical experience and on the physiopathology of the specific endocrine disease taken into account. This document is addressed to all specialists who approach patients with diabetes mellitus secondary to endocrine disorders characterized by an excess of counterregulatory hormones, in order to take better care of these patients. Care and control of diabetes mellitus should be one of the primary goals in patients with an excess of counterregulatory hormones requiring immediate and aggressive treatment.

Nomogram for Predicting Intraoperative Hemodynamic Instability in Patients With Normotensive Pheochromocytoma

CONTEXT

Intraoperative hemodynamic instability (HI) deteriorates surgical outcomes of patients with normotensive pheochromocytoma (NP).

OBJECTIVE

To characterize the hemodynamics of NP and develop and externally validate a prediction model for intraoperative HI.

METHODS

Data on 117 patients with NP (derivation cohort) and 40 patients with normotensive adrenal myelolipoma (NAM) who underwent laparoscopic adrenalectomy from January 2011 to November 2021 were retrospectively collected. Data on 22 patients with NP (independent validation cohort) were collected from another hospital during the same period. The hemodynamic characteristics of patients with NP and NAM were compared. Machine learning models were used to identify risk factors associated with HI. The final model was visualized via a nomogram.

RESULTS

Forty-eight (41%) out of 117 patients experienced HI, which was significantly more than that for NAM. A multivariate logistic regression including age, tumor size, fasting plasma glucose, and preoperative systolic blood pressure showed good discrimination measured by area under curve (0.8286; 95% CI 0.6875-0.9696 and 0.7667; 95% CI 0.5386-0.9947) for predicting HI in internal and independent validation cohorts, respectively. The sensitivities and positive predictive values were 0.6667 and 0.7692 for the internal and 0.9167 and 0.6111 for the independent validations, respectively. The final model was visualized via a nomogram and yielded net benefits across a wide range of risk thresholds in decision curve analysis.

CONCLUSION

Patients with NP experienced HI during laparoscopic adrenalectomy. The nomogram can be used for individualized prediction of intraoperative HI in patients with NP.

Pathophysiology and Management of Glycemic Alterations before and after Surgery for Pheochromocytoma and Paraganglioma

Glycemic alterations are frequent in patients with pheochromocytoma and paraganglioma (PPGL), but the real incidence of secondary diabetes mellitus (DM) is uncertain, because prospective multicenter studies on this topic are lacking in the literature. The main pathophysiological mechanisms of glucose homeostasis alterations in PPGL, related to catecholamine hypersecretion, are impaired insulin and glucagon-like peptide type 1 (GLP-1) secretion and increased insulin resistance. Moreover, it has been reported that different pathways leading to glucose intolerance may be related to the secretory phenotype of the chromaffin tumor. Predictive factors for the development of glucose intolerance in PPGL patients are a higher age at diagnosis, the need for a higher number of anti-hypertensive drugs, and the presence of secreting neoplasms. Tumor resection is strongly related to the resolution of DM in PPGL patients, with a significant improvement of glycemic control in most cases. We can hypothesize a different personalized therapeutic approach based on the secretory phenotype. The adrenergic phenotype is more closely related to reduced insulin secretion, so insulin therapy may be required. On the other hand, the noradrenergic phenotype mainly acts by increasing insulin resistance and, therefore, insulin-sensitizing antidiabetic agents can find a greater application. Regarding GLP-1 receptor agonists, the data suggest a possible promising therapeutic effect, based on the assumption that GLP-1 secretion is impaired in patients with PPGL. The principal predictors of remission of glycemic alterations after surgery for PPGL are a lower preoperative body mass index (BMI), a larger tumor, higher preoperative catecholamine levels, and a shorter duration of the disease (under three years). Otherwise, after resection of PPGL, hypoglycemia can occur as the result of an excessive rebound of preoperative hyperinsulinemia. It is a rare, but potentially severe complication reported in a lot of case reports and a few small retrospective studies. Higher 24-h urinary metanephrine levels, longer operative times and larger tumors are predictive factors for hypoglycemia in this setting. In conclusion, alterations of carbohydrate metabolism are clinically relevant manifestations of PPGL before and after surgery, but there is the need to conduct multicenter prospective studies to obtain an adequate sample size, and to allow the creation of shared strategies for the clinical management of these potentially severe manifestations of PPGL.

Influence of duration of preoperative treatment with phenoxybenzamine and secretory phenotypes on perioperative hemodynamics and postoperative outcomes in pheochromocytoma and paraganglioma

Objectives

Resection of pheochromocytoma and paraganglioma (PPGL) carries risks with perioperative hemodynamic instability. Phenoxybenzamine (PXB) is a commonly used α-blockade to prevent it. It is unclear whether lengthening the preoperative duration of PXB is better for hemodynamic stability and postoperative outcomes. Furthermore, different types of catecholamines have varying effects on perioperative hemodynamics. Thus, our study aimed to investigate the impact of the duration of preoperative preparation with PXB and secretory phenotypes of the patients on intraoperative hemodynamic stability and postoperative complications in PPGL.

Methods

Between Dec 2014 and Jan 2022, 166 patients with PPGL were operated on by the same team at Sun Yat-sen Memorial Hospital. They were divided into group A(1-14d), Group B(15-21d), and Group C(>21d) based on the duration of management with PXB and into the adrenergic and the noradrenergic phenotype group based on secretory profiles. Data on intraoperative hemodynamics and postoperative outcomes were collected and compared among groups.

Results

A total of 96 patients occurred intraoperative hemodynamic instability, and 24 patients had 29 postoperative complications related to the surgery. Among the 145 patients treated with PXB, no significant differences were found in the cumulative time outside the target blood pressure(6.67%[0-17.16%] vs. 5.97%[0-23.08%] vs. 1.22%[0-17.27%], p=0.736) or in the median total HI-score(42.00[30.00-91.00] vs. 89.00[30.00-113.00] vs. 49.00[30.00-93.00], p=0.150) among group A(n=45), B(n=51) and C(n=49). Multivariate analysis demonstrated that the level of plasma-free metanephrine(MN) was an independent risk factor for intraoperative hemodynamic instability. And the median cumulative time outside of the target blood pressure in the adrenergic phenotype group was significantly greater than that in the noradrenergic phenotype group(8.17%[0-26.22%] vs. 1.86%[0-11.74%], p=0.029). However, the median total HI-score(99.50[85.00-113.25] vs. 90.00[78.00-105.00], p=0.570) and postoperative outcomes showed no differences between the two groups.

Conclusions

A preoperative duration of nearly 14 days with PXB is sufficient for ensuring intraoperative hemodynamic stability in PPGL. And lengthening the preparation duration may not provide additional benefits in the era of widespread application and advanced techniques of laparoscopic surgery. Additionally, patients with the adrenergic phenotype are more prone to intraoperative hemodynamic instability than the noradrenergic phenotype. Thus, more attention should be given to the adrenergic phenotype during surgery.

Hypermetabolism and Substrate Utilization Rates in Pheochromocytoma and Functional Paraganglioma

The overproduction of catecholamines in pheochromocytoma/paraganglioma (PPGL) induces a hypermetabolic state. The aim of this study was to evaluate the incidence of a hypermetabolic state and differences in substrate metabolism in consecutive PPGL patients divided by catecholamine phenotype. Resting energy expenditure (REE) and respiratory quotient (RQ) were measured in 108 consecutive PPGL patients and 70 controls by indirect calorimetry. Hypermetabolic state was defined according to the Mifflin St. Jeor Equation as a ratio above 110%. Hypermetabolic state was confirmed in 70% of PPGL patients, regardless of phenotype. Older age, prevalence of diabetes mellitus and arterial hypertension were correlated with hypermetabolic PPGL as compared to normometabolic form. Analysis according to overproduced catecholamine showed differences in VCO2 (p < 0.05) and RQ (p < 0.01) and thus different substate metabolism between phenotypes in hypermetabolic form of PPGL. Lipid utilization was higher in the adrenergic phenotype (p = 0.001) and positively associated with the percentage of REE ratio (R = 0.48, p < 0.001), whereas the noradrenergic phenotype preferentially oxidizes carbohydrates (P = 0.001) and is correlated with the percentage of REE ratio (R = 0.60, p < 0.001). Hypermetabolic state in PPGL is a common finding in both catecholamine phenotypes. Hypermetabolic PPGL patients are older and suffer more from diabetes mellitus and arterial hypertension. Under basal conditions, the noradrenergic type preferentially metabolizes carbohydrates, whereas the adrenergic phenotype preferentially metabolizes lipids.

Gene Profile of Adipose Tissue of Patients with Pheochromocytoma/Paraganglioma

Background: Brown adipose tissue (BAT) is a therapeutic target to combat obesity and related disorders. Pheochromocytoma and functional paraganglioma (PPGL) are associated with activated BAT due to catecholamine excess. Our aim was to evaluate BAT activity by gene profile and assess its relation to clinical characteristics and overproduced catecholamine. Methods: mRNA expression of 15 genes in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) was measured via RT-PCR in 25 patients with PPGL and 14 controls undergoing cholecystectomy. Results: We found in VAT of PPGL higher expression of UCP1 (p < 0.001), CEBPB, PPARGC1A (both p < 0.001), PRDM16 (p = 0.069) and DIO2 (p = 0.005). UCP1 expression correlated only with norepinephrine levels and its metabolite. UCP1 expression, among others, correlated negatively with BMI, age and positively with HDLc levels. Dominance of BAT or BeAT markers was not assessed in PPGL. In SAT of PPGL, we found higher expression of ADRB3, CIDEA (both p < 0.05), and PPARGC1A (p = 0.001), but not UCP1. Conclusion: We demonstrate signs of UCP1-dependent norepinephrine-induced thermogenesis connected with higher expression of DIO2, PPARGC1A, CEBPB and PRDM16 in retroperitoneal VAT of PPGL and its relations to circulating HDLc and triglycerides levels. However, no direct relationship with increased basal energy metabolism measured by calorimetry was found.

Circulating GLP-1 Levels in Patients with Pheochromocytoma/Paraganglioma

The sympathoadrenal system has been shown to stimulate the secretory activity of enteroendocrine cells, although the response is transient. Our aim was to investigate the effects of long-term catecholamine excess on circulating glucagon-likepeptide-1 (GLP-1) levels in patients with pheochromocytoma/paraganglioma (PPGL). Thirty patients diagnosed with PPGL were analyzed. A significant negative association was observed between fasting plasma GLP-1 levels and elevated plasma-free metanephrine (r = -0.407, p = 0.026). After adjustment for age, sex, body mass index (BMI), serum creatinine, and the presence of hyperglycemia, the negative association between plasma GLP-1 and metanephrine persisted by multiple linear regression analysis (β = -0.493, p = 0.013). Positive correlations between fasting glucose and plasma metanephrine (r = 0.380, p = 0.038) and normetanephrine levels (r = 0.450, p = 0.013) were also found. Mean fasting levels of total GLP-1 increased significantly from 25.81 to 39.01 pmol/L (p = 0.017) after PPGL resection. In conclusion, long-term overproduction of catecholamines appears to induce suppression of GLP-1 production compared to an acute response to a stress stimulus. Further studies are required to elucidate the mechanism of GLP-1 secretion with chronic exposure to catecholamine.

Influence of secretory phenotype and preoperative preparation on surgical outcome in pheochromocytoma

OBJECTIVES

Surgery of pheochromocytomas (PCs) still carries a high risk of haemodynamic complications during the perioperative period. We aimed to evaluate the influence of their secretory phenotype and preoperative alpha-blocker treatment on surgical outcome.

DESIGN

A retrospective monocentric study at a tertiary medical centre.

PATIENTS

In this study, 80 consecutive patients operated by the same team for a PC between 1988 and 2018.

RESULTS

Diagnosis was based on typical symptoms and signs in 58 patients, genetic testing in 12 and work-up of an adrenal incidentaloma in 9. It was made during surgery in one patient. A genetic predisposition was found in one-third of index cases (21/62). The majority of the patients (73/79) had a secreting PC; more than 2/3 had an adrenergic phenotype and less than 1/3 a noradrenergic phenotype. The rate of perioperative haemodynamic complications was not influenced by the secretory phenotype, but persistent hypertension after surgery, recurrence and malignancy were more frequently observed in patients with a noradrenergic tumour. Preoperative alpha-blocker treatment was given for ≥ 14 days in 29 patients and, although being more symptomatic at diagnosis, these patients had less haemodynamic complications (3/29 vs 12/51 non-treated patients, P = 0.05).

CONCLUSIONS

The occurrence of haemodynamic complications during surgery was not significantly affected by the secretory phenotype in our study, but noradrenergic tumours show a worse post-surgical outcome. Our data also provide additional support in favour of a sufficient preoperative alpha-blockade in patients with pheochromocytoma.

Management of 3 Cases of Pheochromocytoma During the COVID-19 Pandemic in New York City: Lessons Learned

The COVID-19 crisis placed a pause on surgical management of nonemergency cases of pheochromocytoma, and it was essential for endocrinologists to provide both resourceful and safe care. At the Mount Sinai Hospital in New York City during the peak of the pandemic, we encountered 3 patients with pheochromocytoma and mild symptoms that were medically managed for a prolonged period of time (7-18 weeks) prior to adrenalectomy. Patients were monitored biweekly via telemedicine, and antihypertensive medications were adjusted according to signs, symptoms, and adrenergic profiles. These cases demonstrate that prolonged medical management prior to surgery is feasible and effective in pheochromocytoma patients with mild symptoms and well-controlled blood pressures.

Glucose Intolerance on Phaeochromocytoma and Paraganglioma-The Current Understanding and Clinical Perspectives

Half of the patients with phaeochromocytoma have glucose intolerance which could be life-threatening as well as causing postoperative hypoglycemia. Glucose intolerance is due to impaired insulin secretion and/or increased insulin resistance. Impaired insulin secretion is caused by stimulating adrenergic α2 receptors of pancreatic β-cells and increased insulin resistance is caused by stimulating adrenergic α1 and β3 receptors in adipocytes, α1 and β2 receptors of pancreatic α-cells and skeletal muscle. Furthermore, different affinities to respective adrenergic receptors exist between epinephrine and norepinephrine. Clinical studies revealed patients with phaeochromocytoma had impaired insulin secretion as well as increased insulin resistance. Furthermore, excess of epinephrine could affect glucose intolerance mainly by impaired insulin secretion and excess of norepinephrine could affect glucose intolerance mainly by increased insulin resistance. Glucose intolerance on paraganglioma could be caused by increased insulin resistance mainly considering paraganglioma produces more norepinephrine than epinephrine. To conclude, the difference of actions between excess of epinephrine and norepinephrine could lead to improve understanding and management of glucose intolerance on phaeochromocytoma.

Long-Term Liraglutide Administration Induces Pancreas Neogenesis in Adult T2DM Mice

In vivo beta-cell neogenesis may be one way to treat diabetes. We aimed to investigate the effect of glucagon-like peptide-1 (GLP-1) on beta-cell neogenesis in type 2 diabetes mellitus (T2DM). Male C57BL/6J mice, 6 wk old, were randomly divided into three groups: Control, T2DM, and T2DM + Lira. T2DM was induced using high-fat diet and intraperitoneal injection of streptozotocin (40 mg/kg/d for 3 d). At 8 wk after streptozotocin injection, T2DM + Lira group was injected intraperitoneally with GLP-1 analog liraglutide (0.8 mg/kg/d) for 4 wk. Apparently for the first time, we report the appearance of a primitive bud connected to pancreas in all adult mice from each group. The primitive bud was characterized by scattered single monohormonal cells expressing insulin, GLP-1, somatostatin, or pancreatic polypeptide, and four-hormonal cells, but no acinar cells and ductal epithelial cells. Monohormonal cells in it were small, newborn, immature cells that rapidly proliferated and expressed cell markers indicative of immaturity. In parallel, Ngn3+ endocrine progenitors and Nestin+ cells existed in the primitive bud. Liraglutide facilitated neogenesis and rapid growth of acinar cells, pancreatic ducts, and blood vessels in the primitive bud. Meanwhile, scattered hormonal cells aggregated into cell clusters and grew into larger islets; polyhormonal cells differentiated into monohormonal cells. Extensive growth of exocrine and endocrine glands resulted in the neogenesis of immature pancreatic lobes in adult mice of T2DM + Lira group. Contrary to predominant acinar cells in mature pancreatic lobes, there were still a substantial number of mesenchymal cells around acinar cells in immature pancreatic lobes, which resulted in the loose appearance. Our results suggest that adult mice preserve the capacity of pancreatic neogenesis from the primitive bud, which liraglutide facilitates in adult T2DM mice. To our knowledge, this is the first time such a phenomenon has been reported.