Exenatide for diagnosing endogenous hyperinsulinemic hypoglycemia: a randomized placebo-controlled, double-blind, cross-over proof-of-principle study.

Objective: The 72 h fasting test, gold standard for diagnosing endogenous hyperinsulinemic hypoglycemia (EHH), is cumbersome and costly. We evaluated exenatide, a GLP-1 receptor agonist, as a faster, less burdensome alternative diagnostic tool.

Design And Methods: In this prospective, placebo-controlled, double-blind, randomized cross-over, proof-of-principle study, 10 μg intravenous exenatide was compared to placebo in 14 patients with confirmed EHH in a fasting test.

Hyponatraemia in ageing.

Hyponatraemia is the most common electrolyte disorder in both inpatient and outpatient settings and mostly affects older adults, in whom intrinsic factors (such as chronic heart, liver or kidney diseases and malignancies) and extrinsic factors (such as polypharmacy and malnutrition) favouring hyponatraemia are highly prevalent. Importantly, its occurrence is expected to increase exponentially with global warming. Chronic hyponatraemia is associated with an increased risk of falling, osteoporosis and fractures, attention deficits, and even mortality.

Disrupted ACTH and cortisol response to osmotic and non-osmotic stress in patients with arginine vasopressin deficiency.

Objective: Arginine vasopressin (AVP), synthesized in the hypothalamus and stored in the posterior pituitary, regulates osmotic balance and stress responses. During stress, AVP enhances corticotropin-releasing hormone-stimulated adrenocorticotropic hormone (ACTH) secretion, with cortisol and AVP providing negative feedback regulation. Disruption in AVP production might impair this feedback, leading to sustained cortisol elevations.

Impact of multikinase inhibitors in reshaping the treatment of advanced gastroenteropancreatic neuroendocrine tumors.

Neuroendocrine tumors (NETs) pose a considerable challenge due to their increasing incidence and frequently late-stage diagnosis. The arrival of multikinase inhibitors (MKIs) into clinical practice has brought notable progress in the management of advanced gastroenteropancreatic neuroendocrine tumors (GEP-NETs). This review aims at exploring the impact of MKIs in reshaping the treatment landscape for advanced GEP-NETs.

A novel diagnostic score for diagnosing arginine vasopressin deficiency (central diabetes insipidus) or primary polydipsia with basal laboratory and clinical parameters: results from two international multicentre prospective diagnostic studies.

Background: Distinguishing arginine vasopressin deficiency (central diabetes insipidus) from primary polydipsia is challenging. There is no validated initial laboratory assessment or diagnostic score to rule-in or rule-out arginine vasopressin deficiency during the first consultation. Therefore, this study aimed to evaluate the diagnostic potential of basal laboratory parameters and to develop a practical diagnostic score.

A post-hoc internal validation of arginine-stimulated copeptin cut-offs for diagnosing AVP deficiency (central diabetes insipidus).

Background: Distinguishing arginine vasopressin (AVP) deficiency (central diabetes insipidus) from primary polydipsia is challenging. While hypertonic saline-stimulated copeptin testing provides the highest diagnostic accuracy, it is often restricted to specialised centres, requiring close monitoring and potentially causing patient discomfort. Initially, arginine-stimulated copeptin was proposed as a simpler alternative, but a head-to-head comparison study found it less precise than hypertonic saline stimulation.

Relationship between plasma urea and copeptin in response to arginine stimulation in healthy adults, patients with vasopressin deficiency and primary polydipsia.

Background: Arginine infusion stimulates copeptin secretion, a surrogate marker of arginine vasopressin (AVP), thereby serving as a diagnostic test in the differential diagnosis of suspected AVP deficiency (AVP-D). Yet, the precise mechanism underlying the stimulatory effect of arginine on the vasopressinergic system remains elusive. Arginine plays a significant role in the urea cycle and increases the production of urea.

Apelin levels in patients with polyuria-polydipsia syndrome upon copeptin stimulation tests.

Objective: Differentiating between arginine vasopressin deficiency (AVP-D) and primary polydipsia (PP) requires a copeptin stimulation test. We aimed to characterize changes in apelin, an endogenous hormone antagonizing AVP, upon copeptin stimulation tests.

Design: Post hoc secondary analysis of a multi-centric cross-over diagnostic study (NCT03572166).

Clinical factors associated with hyponatremia correction during treatment with oral urea.

Background: Oral urea is being used more commonly to treat hyponatremia, but factors contributing to the correction rate are unknown. We hypothesized that clinically relevant factors can be identified to help guide hyponatremia correction with oral urea.

Methods: This was a retrospective study in two university hospitals including hospitalized patients with hyponatremia (plasma sodium <135 mmol/L) treated with oral urea.

Apelin and Copeptin Levels in Patients With Chronic SIAD Treated With Empagliflozin.

Background: Empagliflozin increases sodium levels in patients with a chronic syndrome of inappropriate antidiuresis (SIAD), and dapagliflozin increases apelin levels in patients with diabetes mellitus. Exogenous apelin increases sodium levels in rats with SIAD. We aimed to investigate whether an increase in plasma apelin concentration may contribute to the efficacy of empagliflozin in SIAD.

Arginine vasopressin deficiency: diagnosis, management and the relevance of oxytocin deficiency.

Polyuria-polydipsia syndrome can be caused by central diabetes insipidus, nephrogenic diabetes insipidus or primary polydipsia. To avoid confusion with diabetes mellitus, the name 'central diabetes insipidus' was changed in 2022 to arginine vasopressin (AVP) deficiency and 'nephrogenic diabetes insipidus' was renamed as AVP resistance. To differentiate the three entities, various osmotic and non-osmotic copeptin-based stimulation tests have been introduced in the past decade.

Impact of sex on treatment decisions and outcome in patients with neuroendocrine neoplasms.

Sex differences affect the management of several diseases in both male and female patients. However, the influence of sex on neuroendocrine neoplasms (NENs) has been scarcely investigated. Thus, this study aimed to compare tumor characteristics, treatment decisions, and overall survival in patients with NENs, stratified by sex.

New insights on diagnosis and treatment of AVP deficiency.

Arginine vasopressin deficiency (AVP-D) is one of the main entities of the polyuria-polydipsia syndrome. Its correct diagnosis and differentiation from the other two causes - AVP resistance and primary polydipsia - is crucial as this determines the further management of these patients.Over the last years, several new diagnostic tests using copeptin, the stable surrogate marker of AVP, have been introduced.

Extracellular sodium regulates fibroblast growth factor 23 (FGF23) formation.

The bone-derived hormone fibroblast growth factor-23 (FGF23) has recently received much attention due to its association with chronic kidney disease and cardiovascular disease progression. Extracellular sodium concentration ([Na]) plays a significant role in bone metabolism. Hyponatremia (lower serum [Na]) has recently been shown to be independently associated with FGF23 levels in patients with chronic systolic heart failure.

Arginine or Hypertonic Saline-Stimulated Copeptin to Diagnose AVP Deficiency.

Background: Distinguishing between arginine vasopressin (AVP) deficiency and primary polydipsia is challenging. Hypertonic saline-stimulated copeptin has been used to diagnose AVP deficiency with high accuracy but requires close sodium monitoring. Arginine-stimulated copeptin has shown similar diagnostic accuracy but with a simpler test protocol.

Approach to the Patient: Insulinoma.

Insulinomas are hormone-producing pancreatic neuroendocrine neoplasms with an estimated incidence of 1 to 4 cases per million per year. Extrapancreatic insulinomas are extremely rare. Most insulinomas present with the Whipple triad: (1) symptoms, signs, or both consistent with hypoglycemia; (2) a low plasma glucose measured at the time of the symptoms and signs; and (3) relief of symptoms and signs when the glucose is raised to normal.

Effect of protein supplementation on plasma sodium levels in the syndrome of inappropriate antidiuresis: a monocentric, open-label, proof-of-concept study-the TREASURE study.

Importance: The syndrome of inappropriate antidiuresis (SIAD) can be treated with oral urea; however, compliance is impaired by its poor palatability.

Objective: To investigate whether dietary proteins could increase plasma sodium levels through urea-induced osmotic diuresis.

Design: An open-label, proof-of-concept trial.

Treatment Guidelines for Hyponatremia: Stay the Course.

International guidelines designed to minimize the risk of complications that can occur when correcting severe hyponatremia have been widely accepted for a decade. On the basis of the results of a recent large retrospective study of patients hospitalized with hyponatremia, it has been suggested that hyponatremia guidelines have gone too far in limiting the rate of rise of the serum sodium concentration; the need for therapeutic caution and frequent monitoring of the serum sodium concentration has been questioned. These assertions are reminiscent of a controversy that began many years ago.

Epigenetic regulation of SST expression in small intestinal neuroendocrine tumors.

Background: Somatostatin receptor type 2 (SST) expression is critical for the diagnosis and treatment of neuroendocrine tumors and is associated with improved patient survival. Recent data suggest that epigenetic changes such as DNA methylation and histone modifications play an important role in regulating SST expression and tumorigenesis of NETs. However, there are limited data on the association between epigenetic marks and SST expression in small intestinal neuroendocrine tumors (SI-NETs).

Improvement of Lung NET Management through Standardized Care-A Swiss Nationwide Observational Study.

Typical (TC) and atypical carcinoids (AC) are the most common neuroendocrine tumors (NETs) of the lung. Because these tumors are rare, their management varies widely among Swiss centers. Our aim was to compare the management of Swiss patients before and after the publication of the expert consensus of the European Neuroendocrine Tumor Society (ENETS) in 2015.

An Increase in Plasma Sodium Levels Is Associated With an Increase in Osteoblast Function in Chronic SIAD.

Context: Hyponatremia is associated with increased risk for osteoporosis. Preclinical studies in untreated hyponatremia suggest osteoclast upregulation, whereas a clinical study showed improved osteoblast function after hyponatremia normalization in hospitalized patients with syndrome of inappropriate antidiuresis (SIAD).

Objective: This work aimed to investigate the effect of an increase in sodium on bone turnover, that is, the ratio of the osteoblast marker procollagen type 1 N-terminal propeptide (P1NP) to the osteoclast marker cross-linked C-terminal telopeptide of type 1 collagen (CTX), in outpatients with chronic SIAD.