The health care experience of adults with metabolic dysfunction-associated steatohepatitis and influence of PNPLA3: A qualitative study

BACKGROUND

Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive form of metabolic dysfunction-associated steatotic liver disease, for which there is limited information about patient experience, including the patient journey.

METHODS

In this study, we conducted interviews with patients with MASH to qualitatively evaluate the patient journey and help elucidate the experiences of this patient population. We also investigated if the patatin-like phospholipase domain-containing protein 3 (PNPLA3) I148M variant (non-Hispanic) or being of Hispanic ethnicity may influence patient experiences because these 2 subgroups develop advanced liver disease more frequently than other patient groups.

RESULTS

One-to-one interviews were conducted with 28 adults (with PNPLA3 I148M genetic variant, n = 10; Hispanic, n = 8) living in the United States who had been diagnosed with MASH with liver fibrosis. Patients were asked open-ended questions about their experiences before, at, and after their diagnosis. The data collected found that patients experienced a long process of misdiagnoses before their diagnosis of MASH, a lack of clear information provided by clinicians, and limited accessibility to support groups. Hispanic patients reported "impact on family/friends" (75%) and "fear of disease progression" (75%) more frequently than the other patient cohorts interviewed. This is the first report of "fear of progression" in patients with MASH. No patients who were White and had the PNPLA3 I148M variant reported nausea/vomiting, in contrast to other patient cohorts.

CONCLUSIONS

This qualitative study identified key aspects of the patient journey that are important for clinical providers and medical teams to recognize. We also propose a new algorithm that could be developed to help screen relatives of patients who are found to carry the PNPLA3 I148M variant.

Non-invasive assessment of hepatic steatosis by ultrasound-derived fat fraction in individuals at high-risk for metabolic dysfunction-associated steatotic liver disease

AIMS

Given the increasing number of individuals developing metabolic dysfunction-associated steatotic liver disease (MASLD) and the low rate of those with progressive liver disease, there is a pressing need to conceive affordable biomarkers to assess MASLD in general population settings. Herein, we aimed to investigate the performance of the ultrasound-derived fat fraction (UDFF) for hepatic steatosis in high-risk individuals.

METHODS

A total of 302 Europeans with obesity, type 2 diabetes, or a clinical history of hepatic steatosis were included in the analyses. Clinical, laboratory, and imaging data were collected using standardized procedures during a single screening visit in Rome, Italy. Hepatic steatosis was defined by controlled attenuation parameter (CAP) or ultrasound-based Hamaguchi's score. UDFF performance for hepatic steatosis was estimated by the area under the receiver operating characteristic curve (AUC).

RESULTS

Overall, median (IQR) UDFF was 12% (7-20). UDFF was positively correlated with CAP (ρ = 0.73, p < 0.0001) and Hamaguchi's score (ρ = 0.79, p < 0.0001). Independent predictors of UDFF were circulating triglycerides, alanine aminotransferase (ALT), and ultrasound-measured visceral adipose tissue (VAT). UDFF AUC was 0.89 (0.85-0.93) and 0.92 (0.88-0.95) for CAP- and ultrasound-diagnosed hepatic steatosis, respectively. UDFF AUC for hepatic steatosis was higher than those of fatty liver index (FLI), hepatic steatosis index (HSI), CAP-score (CAPS), and ALT (p < 0.0001). Lower age, ALT, and VAT were associated with discordance between UDFF and ultrasound.

CONCLUSIONS

UDFF may be a simple and accurate imaging biomarker to assess hepatic steatosis and monitor changes in hepatic fat content over time or in response to therapeutic interventions beyond clinical trials.

Blood-based Proteomic Signatures Associated With MEN1-related Duodenopancreatic Neuroendocrine Tumor Progression

PURPOSE

Patients with multiple endocrine neoplasia type 1 (MEN1) are predisposed to develop duodenopancreatic neuroendocrine tumors (dpNETs), and metastatic dpNET is the primary cause of disease-related mortality. Presently, there is a paucity of prognostic factors that can reliably identify patients with MEN1-related dpNETS who are at high risk of distant metastasis. In the current study, we aimed to establish novel circulating molecular protein signatures associated with disease progression.

EXPERIMENTAL DESIGN

Mass spectrometry-based proteomic profiling was conducted on plasmas procured through an international collaboration between MD Anderson Cancer Center, the National Institutes of Health, and the University Medical Center Utrecht from a cohort of 56 patients with MEN1 [14 with distant metastasis dpNETs (cases) and 42 with either indolent dpNETs or no dpNETs (controls)]. Findings were compared to proteomic profiles generated from serially collected plasmas from a mouse model of Men1-pancreatic neuroendocrine tumors (Men1fl/flPdx1-CreTg) and control mice (Men1fl/fl).

RESULTS

A total of 187 proteins were found to be elevated in MEN1 patients with distant metastasis compared to controls, including 9 proteins previously associated with pancreatic cancer and other neuronal proteins. Analyses of mouse plasmas revealed 196 proteins enriched for transcriptional targets of oncogenic MYCN, YAP1, POU5F1, and SMAD that were associated with disease progression in Men1fl/flPdx1-CreTg mice. Cross-species intersection revealed 19 proteins positively associated with disease progression in both human patients and in Men1fl/flPdx1-CreTg mice.

CONCLUSIONS

Our integrated analyses identified novel circulating protein markers associated with disease progression in MEN1-related dpNET.

The greater impact of PNPLA3 polymorphism on liver-related events in Japanese non-alcoholic fatty liver disease patients: A multicentre cohort study

BACKGROUND & AIMS

PNPLA3 rs738409 has been associated with an increased risk of liver-related events in patients with non-alcoholic fatty liver disease (NAFLD). In this study, we investigated the epidemiology of NAFLD and the impact of PNPLA3 on prognosis in Japan.

METHODS

A longitudinal multicentre cohort study, the JAGUAR study, includes 1550 patients with biopsy-proven NAFLD in Japan. We performed genetic testing and evaluated outcomes from this cohort. Liver-related events were defined as hepatocellular carcinoma (HCC) and decompensated liver cirrhosis events.

RESULTS

During follow-up (median [range], 7.1 [1.0-24.0] years), 80 patients developed HCC, 104 developed liver-related events, and 59 died of any cause. The 5-year rate of liver-related events for each single-nucleotide polymorphism was 0.5% for CC, 3.8% for CG, and 5.8% for GG. Liver-related deaths were the most common (n = 28); only three deaths were due to cardiovascular disease. Multivariate analysis identified carriage of PNPLA3 CG/GG (hazard ratio [HR] 16.04, p = .006) and FIB-4 index >2.67 (HR 10.70, p < .01) as predictors of liver-related event development. No HCC or liver-related death was found among patients with PNPLA3 CC. There was a significantly increased risk of HCC, liver-related events, and mortality for CG/GG versus CC, but no difference between the CG and GG genotypes.

CONCLUSIONS

In Japanese individuals, the main cause of death from NAFLD is liver-related death. The greater risk of liver-related events incurred by PNPLA3 G allele was shown in Japan. Risk stratification for NAFLD in Japan is best accomplished by integrating PNPLA3 with the FIB-4 index.

Abstract P066: Blood-based proteomic signatures associated with MEN1-related duodenopancreatic neuroendocrine tumor progression

Multiple Endocine Neoplasia Type 1 (MEN1) is associated with duodenopancreatic neuroendocrine tumors (dpNETs) and metastatic dpNET is the primary cause of disease-related mortality for this condition. Currently, there is a paucity of prognostic factors that can reliably identify patients with MEN1-related dpNETS who are at high risk of distant metastasis. Previously, we uncovered a blood-based polyamine metabolite signature that was associated with MEN1-dpNET disease progression. In the current study, we aimed to build upon our prior findings, by exploring the contributions of proteomics for identifying circulating protein markers associated with tumor progression. We performed in-depth proteomic analysis of serially collected plasmas from a genetically engineered mouse model of Men1-pNET, Men1fl/flPdx1-CreTg, and Men1fl/fl control mice to assess dynamic changes in the plasma proteome that associated with disease progression. Findings were compared to plasma proteomic profiles from a cohort of 56 patients with MEN1 (14 with distant metastasis dpNETs (cases) and 42 with either indolent dpNETs or no dpNETs (controls)). Analyses revealed 196 proteins related to oncogenic N-MYC, YAP1, POU5F1, and SMAD that were positively associated with pNET disease progression in Men1fl/flPdx1-CreTg mice. Similarly, 187 proteins were elevated in MEN1 patients with distant metastasis compared controls. Proteins with increased levels in metastatic cases included AMY2B, CELA3B, RNASE1, IGFBP2, CHI3L1, LYZ, TIMP1, LRG1, and COL18A1 previously associated with pancreatic cancer and other neuronal proteins. Cross-species intersection revealed 19 proteins including NDC80, DEF8, SPAG17, ATM, IMMT, DNAH6, DSP, CIT, HRG, CD79A, BDP1, SERPINA11, TARBP1, and SERPIND1 that were positively associated with disease progression in Men1fl/flPdx1-CreTg mice and human subjects. Our integrated analyses identified novel circulating protein features associated with disease progression in MEN1-related dpNET.

Citation Format: Johannes F. Fahrmann, Amanda R. Wasylishen, Carolina R.C. Pieterman, Ehsan Irajizad, Jody Vykoukal, Ranran Wu, Jennifer D. Dennison, Christine B. Peterson, Guillermina Lozano, Hua Zhao, Kim-Ahn Do, Daniel M. Halperin, Sunita K. Agarwal, Jenny E. Blau, Jaydira D. Rivero, Naris Nilubol, Mary F. Walter, James M. Welch, Lee S. Weinstein, Menno R. Vriens, Rachel S. van Leeuwaarde, Mark J.C. van Treijen, Gerlof D. Valk, Nancy D. Perrier, Sam M Hanash, Hiroyuki Katayama. Blood-based proteomic signatures associated with MEN1-related duodenopancreatic neuroendocrine tumor progression. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P066.

ODP300 c-MET expression in MEN1-associated neuroendocrine tumors

 

Multiple studies have shown that approximately 50-70% of patients with MEN1 die of causes directly related to MEN1 particularly gastroenteropancreatic (GEP) neuroendocrine tumors (NETs). While non-functional GEP-NETs are the most common in the general population, gastrinomas (40%) are the most common functional GEP-NETs in patients with MEN1. c-MET is a proto-oncogene that encodes for c-MET, a tyrosine kinase receptor which promotes tumor cell motility, proliferation, survival, invasion, and metastasis. Studies in patients with sporadic gastrinomas and pancreatic NETs (PNETs) have shown that c-MET expression correlates with decreased survival.

While c-MET inhibitors are currently in various stages of investigation for treatment of carcinoids and sporadic PNETs, data regarding their efficacy in patients with MEN1-related GEP NETs is lacking. The majority of trials in patients with GEP-NETs exclude or do not report the number of patients with MEN1. Importantly, somatic MEN1 mutations are observed in 20-40% of sporadic NETs (gastrinomas, PNETs, lung NETs, etc.) but correlation of cMET expression with the presence of somatic or germline MEN1 mutations has not been reported. We sought to investigate the expression of c-MET in tumor tissue from germline MEN1 patients with metastatic GEP-NETs.

Methods

We identified subjects with a germline positive MEN1 mutation and pathologically confirmed distant metastasis who had a follow-up visit between 2018-2020. Of these, we selected subjects with available tissue specimens (including either multiple organ sources or different tumor types). Where available, we identified specimens from multiple source or tumor types. Immunohistochemistry (IHC) to detect c-MET was performed with anti-MET (Cell Signaling) using the DAKO IHC kit (Agilent). IHC slides were imaged and observed to score the level of c-MET staining (-, 1+ to 5+). A score of 3+ or higher was considered consistent with overexpression. We investigated if age at initial GEP-NET presentation, tumor type, tissue source, tumor grade, total number of surgeries for GEP-NET, number of sites of distant metastasis and disease status from overall GEP-NET burden over the preceding 12 months (stable/progressive) predicted c-MET expression.

Results

Eight subjects with available tissue specimens were identified, of which six had tissue from multiple organs while five had tissue from multiple tumor types. Six subjects (75%) showed increased expression of c-MET in one or more tumor specimen(s). The frequency of c-MET overexpression varied with tumor types – carcinoids (n=2/2; 100%), gastrinomas (n=3/5; 60%) and non-functional tumors (n=3/6; 50%). c-MET expression also varied among different tumors in the same patient. Tumor tissue from liver (n=2/2), duodenum (n=3/4), stomach (n=1/1), ovary (n=1/1), pancreas (n= 1/5), and lymph nodes (n=1/3), all showed over-expression of c-MET. No clear predictors of c-MET overexpression emerged.

Conclusion

Our finding suggests a role for c-MET expression in personalizing therapy for patients with MEN1-related NETs with distant metastases.

Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m., Sunday, June 12, 2022 12:48 p.m. - 12:53 p.m.

Determination of FGF23 Levels for the Diagnosis of FGF23-Mediated Hypophosphatemia

Fibroblast growth factor-23 (FGF23) measurement is a critical tool in the evaluation of patients with disordered phosphate homeostasis. Available laboratory reference ranges for blood FGF23 were developed using samples from normophosphatemic individuals. Reliance on such values can lead to misdiagnosis in patients with FGF23-mediated hypophosphatemia, such as X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), in whom pathology-driving FGF23 levels can be in the "normal range." To determine FGF23 levels that are diagnostic for the identification of patients with FGF23-mediated hypophosphatemic disorders, we studied 149 patients with various disorders of FGF23-mediated and FGF23-independent hypophosphatemia and defined cut-off levels for both intact FGF23 (iFGF23) and C-terminal FGF23 (cFGF23) that can accurately distinguish between FGF23-mediated and FGF23-independent hypophosphatemia. In addition, to demonstrate the relationship between FGF23 and phosphate across the spectrum of human physiology, we assessed blood levels of FGF23 and phosphate in 434 patients with various forms of hypophosphatemia, hyperphosphatemia, and normophosphatemia. An intact FGF23 cut point of 27 pg/mL was 100% sensitive and specific in distinguishing FGF23-mediated from FGF23-independent hypophosphatemia, and a cFGF23 cut point of 90 RU/mL was 100% sensitive and specific in distinguishing specifically TIO from FGF23-independent hypophosphatemia. There was overlap in the cFGF23 range of 45-90 RU/mL between genetic forms of FGF23 excess and FGF23-independent hypophosphatemia, substantiating the superiority of iFGF23 over cFGF23 in making the diagnosis of FGF23-mediated hypophosphatemia. In this cohort, using the laboratory upper limit of normal for cFGF23 (180 RU/mL) would result in a misdiagnosis in more than half of patients with FGF23-mediated hypophosphatemia. In this, the largest study of FGF23 in chronic hypophosphatemia to date, we established iFGF23 and cFGF23 cut-off values to assist in the evaluation and diagnosis of hypophosphatemic conditions. © 2022 American Society for Bone and Mineral Research (ASBMR). This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Metastatic Grade 3 Neuroendocrine Tumor in Multiple Endocrine Neoplasia Type 1 (MEN1) Expressing Somatostatin Receptors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) can occur in 30-90% of patients with Multiple Endocrine Neoplasia Type 1 (MEN1). However, only 1% of GEP-NETs are Grade 3 (G3). Given the rarity of these aggressive tumors, treatment of advanced G3 GEP-NETs in MEN1 is based on the treatment guidelines for sporadic GEP-NETs. We report a 43-year-old male with germline MEN1 followed at our institution with clinical features including hyperparathyroidism, a non-functional pancreatic NET, and Zollinger-Ellison Syndrome. On routine surveillances imaging, at age 40, computer tomography (CT/ positron emission tomography (PET)) imaging showed two arterially enhancing intraluminal masses on the medial aspect of the gastric wall. Anatomical imaging confirmed two enhancing masses within the pancreas and a rounded mass-like thickening along the lesser curvature of the stomach. The gastric mass was resected, and pathology reported a well-differentiated G3 NET with a Ki-67 &gt;20%. The patient continued active surveillance. Eighteen months later cross-sectional imaging studies showed findings consistent with metastatic disease within the right hepatic lobe and bland embolization was done. On follow-up scans, including 68Ga-DOTATATE (68Ga-DOTA(0)-Tyr(3)-octreotate) imaging, interval increase in number and avidity of metastatic lesions were compatible with disease progression. Given a paucity of treatment recommendations for G3 tumors in MEN1, the patient was counseled based on standard NET treatment guidelines and recommended 177Lu-DOTATATE treatment. PRRT (peptide receptor radionuclide therapy) with 177Lu-DOTATATE ( 177Lu-tetraazacyclododecanetetraacetic acid-octreotide) is an important therapeutic modality for patients with somatostatin receptor-positive (SSTR) NETs. However, prospective studies are needed to understand the role of PRRT in G3 NETs.

A Blood-based Polyamine Signature Associated With MEN1 Duodenopancreatic Neuroendocrine Tumor Progression

CONTEXT

Duodenopancreatic neuroendocrine tumors (dpNETs) frequently occur in patients with multiple endocrine neoplasia type 1 (MEN1), and metastatic dpNET is the primary cause of disease-related mortality. There is a need for biomarkers that can identify patients with MEN1-related dpNETs that are at high risk of developing distant metastasis. Polyamines have tumor-promoting roles in several cancer types.

OBJECTIVE

We hypothesized that MEN1-dpNET-related disease progression is associated with elevated levels of circulating polyamines.

METHODS

Through an international collaboration between The University of Texas MD Anderson Cancer Center, the National Institutes of Health, and the University Medical Center Utrecht, plasma polyamine levels were assessed using mass spectrometry in 84 patients with MEN1 (20 with distant metastatic dpNETs [patients] and 64 with either indolent dpNETs or no dpNETs [controls]). A mouse model of MEN1-pNET, Men1fl/flPdx1-CreTg, was used to test time-dependent changes in plasma polyamines associated with disease progression.

RESULTS

A 3-marker plasma polyamine signature (3MP: N-acetylputrescine, acetylspermidine, and diacetylspermidine) distinguished patients with metastatic dpNETs from controls in an initial set of plasmas from the 3 participating centers. The fixed 3MP yielded an area under the curve of 0.84 (95% CI, 0.62-1.00) with 66.7% sensitivity at 95% specificity for distinguishing patients from controls in an independent test set from MDACC. In Men1fl/flPdx1-CreTg mice, the 3MP was elevated early and remained high during disease progression.

CONCLUSION

Our findings provide a basis for prospective testing of blood-based polyamines as a potential means for monitoring patients with MEN1 for harboring or developing aggressive disease.

Parathyroid Hormone Resistance and Autoantibodies to the PTH1 Receptor

We describe two cases of acquired parathyroid hormone (PTH) resistance consequent to the development of serum PTH type 1 receptor (PTH1R) autoantibodies, which block PTH binding and signaling. Both cases were associated with other autoimmune manifestations, and one case was associated with atypical membranous glomerulonephritis. In vitro binding and signaling assays identified the presence of PTH1R-blocking IgG autoantibodies, which were not present in serum samples from patients with other renal or autoimmune disorders. (Funded by the Intramural Research Programs of the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Two distinct classes of thymic tumors in patients with MEN1 show LOH at the MEN1 locus

Patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome carry germline heterozygous loss-of-function mutations in the MEN1 gene which predisposes them to develop various endocrine and non-endocrine tumors. Over 90% of the tumors show loss of heterozygosity (LOH) at chromosome 11q13, the MEN1 locus, due to somatic loss of the wild-type MEN1 allele. Thymic neuroendocrine tumors (NETs) or thymic carcinoids are uncommon in MEN1 patients but are a major cause of mortality. LOH at the MEN1 locus has not been demonstrated in thymic tumors. The goal of this study was to investigate the molecular aspects of MEN1-associated thymic tumors including LOH at the MEN1 locus and RNA-sequencing (RNA-Seq) to identify genes associated with tumor development and potential targeted therapy. A retrospective chart review of 294 patients with MEN1 germline mutations identified 14 patients (4.8%) with thymic tumors (12 thymic NETs and 2 thymomas). LOH at the MEN1 locus was identified in 10 tumors including the 2 thymomas, demonstrating that somatic LOH at the MEN1 locus is also the mechanism for thymic tumor development. Unsupervised principal component analysis and hierarchical clustering of RNA-Seq data showed that thymic NETs formed a homogenous transcriptomic group separate from thymoma and normal thymus. KSR2 (kinase suppressor of Ras 2), that promotes Ras-mediated signaling, was abundantly expressed in thymic NETs, a potential therapeutic target. The molecular insights gained from our study about thymic tumors combined with similar data from other MEN1-associated tumors may lead to better surveillance and treatment of these rare tumors.

Cockayne syndrome, MEN1, and genomic variants: Exome sequencing is changing our view of the genetic landscape

The availability of genomic sequencing for inherited diseases provides a more complete molecular basis for how an individual's genetic landscape influences clinical outcome. We describe a family where exome sequencing of a 3-year-old boy with clinical features of Cockayne syndrome (CS) confirmed the diagnosis of CS. He also had a mutation consistent with a pre-symptomatic second disease, multiple endocrine neoplasia type 1 (MEN1), each potentially affecting multiple organ systems, in addition to a poorly defined variant in fumarate hydratase (FH). Genomic sequencing may reveal coexisting pathogenic mutations and variants which complicate clinical interpretation.

Insulin sensitivity and pancreatic β-cell function in patients with primary aldosteronism

BACKGROUND

Primary aldosteronism (PA) is associated with an increased risk for dysglycemia. However, the effects of hyperaldosteronism on insulin sensitivity and β-cell function are unclear.

METHODS

Using a cross-sectional study design, we assessed insulin sensitivity and pancreatic β-cell function from an oral glucose tolerance test (OGTT) in patients from two cohorts: subjects with PA (n = 21) and essential hypertension control (EHC) subjects (n = 22). Age, sex, BMI, and mean arterial pressure adjusted measures of insulin sensitivity and β-cell function were compared between the groups.

RESULTS

PA individuals were less insulin sensitive compared to EHC subjects (Quantitative insulin sensitivity check index [QUICKI]: 0.340 ± 0.006 vs. 0.374 ± 0.013, p < 0.001; Matsuda index: 4.14 ± 0.49 vs. 7.87 ± 1.42, p < 0.001; S_I: 11.45 ± 4.85 vs. 21.23 ± 6.11 dL/kg/min per μU/mL, p = 0.02). The hepatic insulin resistance index (HIRI) was higher in PA subjects (PA: 5.61 ± 1.01 vs. EHC: 4.13 ± 0.61, p = 0.002). The insulinogenic index (IGI), an index of β-cell function was higher in the PA cohort (PA: 1.49 ± 0.27 vs. 1.11 ± 0.21 μU/mL/mg/dL, p = 0.03). However, the oral disposition index (DI) was similar between the groups (PA: 4.77 ± 0.73 vs. EHC: 5.46 ± 0.85, p = 0.42), which likely accounts for the similar glucose tolerance between the two cohorts, despite lower sensitivity.

CONCLUSIONS

In summary, insulin sensitivity is significantly lower in PA with an appropriately compensated β-cell function. These results suggest that excess aldosterone and/or other steroids in the context of PA may negatively affect insulin action without adversely impacting β-cell function.

Patients With MEN1 Are at an Increased Risk for Venous Thromboembolism

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited disorder predisposing the development of multiple functional and nonfunctional neuroendocrine tumors (NETs). Only uncommon MEN1-associated functional NETs such as glucagonomas (<1%) and adenocorticotropic hormone-producing tumors (<5%) are known to be associated with hypercoagulability. It is unknown if patients with MEN1 generally have an increased risk of venous thromboembolism (VTE).

METHODS

We queried a prospective natural history study of germline mutation-positive MEN1 patients (n = 286) between 1991 and 2019 for all lifetime events of VTE. The search terms were: DVT, thromb, embol, PE, pulmonary embolism, clot, hematology consult, anticoagulant, coumadin, lovenox, xarelto, warfarin, aspirin, rivaroxaban, and apixaban. Incidence rates were calculated, accounting for age and sex. Comparisons were made to published incidence rates in healthy populations, different types of cancer, and Cushing's syndrome.

RESULTS

Thirty-six subjects (median age 45 years, range 16-75) experienced a VTE event, yielding a prevalence rate of 12.9%. The age-sex adjusted incidence rate of VTE is 9.11 per 1000 patient-years, with a sex-adjusted lifetime incidence rate of 2.81 per 1000 patient-years. MEN1-associated lifetime incidence rates are ~2-fold higher than the estimated annual incidence rate in the general population and are comparable to the known risk in the setting of various types of cancer. Approximately 80% of patients who had a VTE were diagnosed with pancreatic NETs, of which 24% were insulinomas. Fourteen patients (42%) experienced perioperative VTE events.

CONCLUSIONS

MEN1 patients have an increased risk of VTE. Further mechanistic investigation and validation from other MEN1 cohorts are needed to confirm the increased prevalence of VTE in MEN1.

Acute oesophageal necrosis in multiple endocrine neoplasia type 1: an undescribed complication

Acute oesophageal necrosis (AEN) is a rare entity that most commonly presents as upper gastrointestinal bleeding. Complex pathophysiology may include oesophageal ischaemia as well as reflux of acidic gastric contents causing oesophageal mucosal injury. Management is supportive and directed at underlying comorbidities however prognosis is poor with complications such as oesophageal perforation, stricture and stenosis. Here we present the case of a 56-year-old man with multiple endocrine neoplasia type 1 (MEN1) and gastro-oesophageal reflux disease who developed AEN as a result of undiagnosed Zollinger-Ellison syndrome (ZES), duodenal ulcer-induced obstruction and hypotension from new-onset atrial fibrillation. AEN as the presentation of MEN1-associated ZES is an unusual presentation of this disease which clinicians, particularly endocrinologists and endoscopists, should be aware of.

Familial Hyperparathyroidism

Regulation of the serum calcium level in humans is achieved by the endocrine action of parathyroid glands working in concert with vitamin D and a set of critical target cells and tissues including osteoblasts, osteoclasts, the renal tubules, and the small intestine. The parathyroid glands, small highly vascularized endocrine organs located behind the thyroid gland, secrete parathyroid hormone (PTH) into the systemic circulation as is needed to keep the serum free calcium concentration within a tight physiologic range. Primary hyperparathyroidism (HPT), a disorder of mineral metabolism usually associated with abnormally elevated serum calcium, results from the uncontrolled release of PTH from one or several abnormal parathyroid glands. Although in the vast majority of cases HPT is a sporadic disease, it can also present as a manifestation of a familial syndrome. Many benign and malignant sporadic parathyroid neoplasms are caused by loss-of-function mutations in tumor suppressor genes that were initially identified by the study of genomic DNA from patients who developed HPT as a manifestation of an inherited syndrome. Somatic and inherited mutations in certain proto-oncogenes can also result in the development of parathyroid tumors. The clinical and genetic investigation of familial HPT in kindreds found to lack germline variants in the already known HPT-predisposition genes represents a promising future direction for the discovery of novel genes relevant to parathyroid tumor development.

Distinct DNA Methylation Signatures in Neuroendocrine Tumors Specific for Primary Site and Inherited Predisposition

PURPOSE

To compare the deoxyribonucleic acid (DNA) methylation signature of neuroendocrine tumors (NETs) by primary tumor site and inherited predisposition syndromes von Hippel-Lindau disease (VHL) and multiple endocrine neoplasia type 1 (MEN1).

METHODS

Genome-wide DNA methylation (835 424 CpGs) of 96 NET samples. Principal components analysis (PCA) and unsupervised hierarchical clustering analyses were used to determine DNA methylome signatures.

RESULTS

Hypomethylated CpGs were significantly more common in VHL-related versus sporadic and MEN1-related NETs (P < .001 for both comparisons). Small-intestinal NETs (SINETs) had the most differentially methylated CpGs, either hyper- or hypomethylated, followed by duodenal NETs (DNETs) and pancreatic NETs (PNETs, P < .001 for all comparisons). There was complete separation of SINETs on PCA, and 3 NETs of unknown origin clustered with the SINET samples. Sporadic, VHL-related, and MEN1-related PNETs formed distinct groups on PCA, and VHL clustered separately, showing pronounced DNA hypomethylation, while sporadic and MEN1-related NETs clustered together. MEN1-related PNETs, DNETs, and gastric NETs each had a distinct DNA methylome signature, with complete separation by PCA and unsupervised clustering. Finally, we identified 12 hypermethylated CpGs in the 1A promoter of the APC (adenomatous polyposis coli) gene, with higher methylation levels in MEN1-related NETs versus VHL-related and sporadic NETs (P < .001 for both comparisons).

CONCLUSIONS

DNA CpG methylation profiles are unique in different primary NET types even when occurring in MEN1-related NETs. This tumor DNA methylome signature may be utilized for noninvasive molecular characterization of NETs, through DNA methylation profiling of biopsy samples or even circulating tumor DNA in the near future.

c-MET inhibition: novel treatment for sporadic and MEN1-associated GEP NETs

Gastroenteropancreatic neuroendocrine tumors (GEP NETs) comprise a heterogenous and diverse group of neoplasms arising from a common neuroendocrine cell origin. The majority of these tumors occur sporadically while ~20% manifest within the context of hereditary syndromes. Germline MEN1 mutations cause a syndrome with an increased susceptibility to multifocal primary GEP NETs. In addition, somatic MEN1 mutations also occur in these sporadic lesions. MEN1 alterations are the most frequent somatic mutation found in pancreatic neuroendocrine tumors. In this review, we explore the implication of the loss of the MEN1-encoded protein menin as a key pathogenic driver in subsets of GEP NETs with downstream consequences including upregulation of the oncogenic receptor c-MET (hepatocyte growth factor receptor). Furthermore, the review will summarize the data related to the clinical presentation, therapeutic standards, and outcomes of these tumors in both sporadic and germline MEN1 mutation-associated contexts. Finally, we present the data on c-MET expression in GEP NETs, clinical trials using c-MET inhibitors and provide an overview of the molecular mechanisms by which c-MET inhibition in these lesions represents a potential precision-medicine targeted approach.

HEREDITARY ENDOCRINE TUMOURS: CURRENT STATE-OF-THE-ART AND RESEARCH OPPORTUNITIES: MEN1-related pancreatic NETs: identification of unmet clinical needs and future directives

The PanNET Working Group of the 16th International Multiple Endocrine Neoplasia Workshop (MEN2019) convened in Houston, TX, USA, 27-29 March 2019 to discuss key unmet clinical needs related to PanNET in the context of MEN1, with a special focus on non-functioning (nf)-PanNETs. The participants represented a broad range of medical scientists as well as representatives from patient organizations, pharmaceutical industry and research societies. In a case-based approach, participants addressed early detection, surveillance, prognostic factors and management of localized and advanced disease. For each topic, after a review of current evidence, key unmet clinical needs and future research directives to make meaningful progress for MEN1 patients with nf-PanNETs were identified. International multi-institutional collaboration is needed for adequately sized studies and validation of findings in independent datasets. Collaboration between basic, translational and clinical scientists is paramount to establishing a translational science approach. In addition, bringing clinicians, scientists and patients together improves the prioritization of research goals, assures a patient-centered approach and maximizes patient involvement. It was concluded that collaboration, research infrastructure, methodologic and reporting rigor are essential to any translational science effort. The highest priority for nf-PanNETs in MEN1 syndrome are (1) the development of a data and biospecimen collection architecture that is uniform across all MEN1 centers, (2) unified strategies for diagnosis and follow-up of incident and prevalent nf-PanNETs, (3) non-invasive detection of individual nf-PanNETs that have an increased risk of metastasis, (4) chemoprevention clinical trials driven by basic research studies and (5) therapeutic targets for advanced disease based on biologically plausible mechanisms.

18F-FDOPA PET/CT accurately identifies MEN1-associated pheochromocytoma

SUMMARY

Pheochromocytoma (PHEO) in multiple endocrine neoplasia type 1 (MEN1) is extremely rare. The incidence is reported as less than 2%. We report a case of a 76-year-old male with familial MEN1 who was found to have unilateral PHEO. Although the patient was normotensive and asymptomatic, routine screening imaging with CT demonstrated bilateral adrenal masses. The left adrenal mass grew from 2.5 to 3.9 cm over 4 years with attenuation values of 9 Hounsfield units (HU) pre-contrast and 15 HU post-contrast washout. Laboratory evaluation demonstrated an adrenergic biochemical phenotype. Both 18F-fluorodeoxyglucose (18F-FDG) PET/CT and 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy demonstrated bilateral adrenal uptake. In contrast, 18F-fluorodihydroxyphenylalanine (18F-FDOPA) PET/CT demonstrated unilateral left adrenal uptake (28.7 standardized uptake value (SUV)) and physiologic right adrenal uptake. The patient underwent an uneventful left adrenalectomy with pathology consistent for PHEO. Post-operatively, he had biochemical normalization. A review of the literature suggests that adrenal tumors >2 cm may be at higher risk for pheochromocytoma in patients with MEN1. Despite a lack of symptoms related to catecholamine excess, enlarging adrenal nodules should be biochemically screened for PHEO. 18F-FDOPA PET/CT may be beneficial for localization in these patients.

LEARNING POINTS

18F-FDOPA PET/CT is a beneficial imaging modality for identifying pheochromocytoma in MEN1 patients. Adrenal adenomas should undergo routine biochemical workup for PHEO in MEN1 and can have serious peri-operative complications if not recognized, given that MEN1 patients undergo frequent surgical interventions. MEN1 is implicated in the tumorigenesis of PHEO in this patient.

Inter- and intra-individual variability of active glucagon-like peptide 1 among healthy adults

Objective:

To determine whether sex, age, and body mass index are correlated with active glucagon-like-peptide 1 concentrations and to investigate glucagon-like-peptide 1 reproducibility during repeated oral glucose tolerance tests.

Methods:

Sixty-one healthy volunteers underwent four 2-hour repeated oral glucose tolerance tests approximately 1 week apart. Because this randomized same-subject crossover trial was designed to investigate effects of non-nutritive sweeteners, participants received 355 mL (12 ounces) of water or a beverage containing non-nutritive sweeteners 10 minutes prior to each oral glucose tolerance test. Blood samples were collected 10 minutes before, and 0, 10, 20, 30, 60, 90, and 120 minutes following ingestion of 75 grams of glucose.

Results:

Basal active glucagon-like-peptide 1, peak glucagon-like-peptide 1, and glucagon-like-peptide 1 area-under-the-curve were higher in men than women (all p ≤0.04), adjusting for body mass index and age. Fasting and stimulated active glucagon-like-peptide 1 results were highly reproducible with little within-subject variability (between-subjects to within-subject variability ratio 4.2 and 3.5 for fasting glucagon-like-peptide 1 and glucagon-like-peptide 1 area-under-the-curve).

Conclusion:

Men had higher active glucagon-like-peptide 1 concentrations than women. In contrast to considerable inter-individual variability of basal and stimulated active glucagon-like-peptide 1 concentrations, intra-individual variability was low, consistent with tight physiological regulation.

Prospective Study of a Novel, Radiation-Free, Reduced-Intensity Bone Marrow Transplantation Platform for Primary Immunodeficiency Diseases

Allogeneic blood or marrow transplantation (BMT) is a potentially curative therapy for patients with primary immunodeficiency (PID). Safe and effective reduced-intensity conditioning (RIC) approaches that are associated with low toxicity, use alternative donors, and afford good immune reconstitution are needed to advance the field. Twenty PID patients, ranging in age from 4 to 58 years, were treated on a prospective clinical trial of a novel, radiation-free and serotherapy-free RIC, T-cell-replete BMT approach using pentostatin, low-dose cyclophosphamide, and busulfan for conditioning with post-transplantation cyclophosphamide-based graft-versus-host-disease (GVHD) prophylaxis. This was a high-risk cohort with a median hematopoietic cell transplantation comorbidity index of 3. With median follow-up of survivors of 1.9 years, 1-year overall survival was 90% and grade III to IV acute GVHD-free, graft-failure-free survival was 80% at day +180. Graft failure incidence was 10%. Split chimerism was frequently observed at early post-BMT timepoints, with a lower percentage of donor T cells, which gradually increased by day +60. The cumulative incidences of grade II to IV and grade III to IV acute GVHD (aGVHD) were 15% and 5%, respectively. All aGVHD was steroid responsive. No patients developed chronic GVHD. Few significant organ toxicities were observed. Evidence of phenotype reversal was observed for all engrafted patients, even those with significantly mixed chimerism (n = 2) or with unknown underlying genetic defect (n = 3). All 6 patients with pre-BMT malignancies or lymphoproliferative disorders remain in remission. Most patients have discontinued immunoglobulin replacement. All survivors are off immunosuppression for GVHD prophylaxis or treatment. This novel RIC BMT approach for patients with PID has yielded promising results, even for high-risk patients.

SGLT2 inhibitors as adjunctive therapy for type 1 diabetes: balancing benefits and risks

Sodium-glucose co-transporter-2 (SGLT2) inhibitors have several beneficial effects in patients with type 2 diabetes, including glucose lowering, weight loss, blood pressure lowering, and a reduced risk of major adverse cardiovascular events. To address high unmet medical need via improved glycaemic control, several clinical trials have been done to assess the efficacy and safety of SGLT2 inhibitors in combination with insulin therapy in patients with type 1 diabetes. In this Personal View, we summarise data from eight clinical trials of canagliflozin, dapagliflozin, empagliflozin, and sotagliflozin in patients with type 1 diabetes. HbA_1c-lowering efficacy was greatest at 8-12 weeks of therapy, but the magnitude of HbA_1c lowering waned with longer duration of treatment (up to 52 weeks). Data are not yet available to establish for how long glycaemic efficacy could be sustained during long-term therapy in patients with type 1 diabetes. Moreover, SGLT2 inhibitor therapy induces serious adverse events, including a roughly six-times increased risk of diabetic ketoacidosis. The US Food and Drug Administration estimated that one additional case of ketoacidosis will occur for every 26 patient-years of exposure of patients with type 1 diabetes to sotagliflozin therapy. Assuming a case mortality of 0·4%, this estimate translates into 16 additional deaths per year per 100 000 patients with type 1 diabetes undergoing treatment. These considerations raise important questions about the risk-to-benefit profile of SGLT2 inhibitors when used as adjunctive therapy in patients with type 1 diabetes.

Clinical presentation and management of primary ovarian neuroendocrine tumor in multiple endocrine neoplasia type 1

SUMMARY

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant condition characterized by parathyroid, anterior pituitary and enteropancreatic endocrine cell tumors. Neuroendocrine tumors occur in approximately in 5-15% of MEN1 patients. Very few cases of ovarian NETs have been reported in association with clinical MEN1 and without genetic testing confirmation. Thirty-three-year-old woman with MEN1 was found to have right adnexal mass on computed tomography (CT). Attempt at laparoscopic removal was unsuccessful, and mass was removed via a minilaparotomy in piecemeal fashion. Pathology showed ovarian NET arising from a teratoma. Four years later, patient presented with recurrence involving the pelvis and anterior abdominal wall. She was treated with debulking surgery and somatostatin analogs (SSAs). Targeted DNA sequencing analysis on the primary adnexal mass as well as the recurrent abdominal wall tumor confirmed loss of heterozygosity (LOH) at the MEN1 gene locus. This case represents to our knowledge, the first genetically confirmed case of ovarian NET arising by a MEN1 mechanism in a patient with MEN1. Extreme caution should be exercised during surgery as failure to remove an ovarian NET en masse can result in peritoneal seeding and recurrence. For patients with advanced ovarian NETs, systemic therapy options include SSAs, peptide receptor radioligand therapy (PRRT) and novel agents targeting mammalian target of rapamycin (mTOR) and vascular endothelial growth factor (VEGF).

LEARNING POINTS

Ovarian NET can arise from a MEN1 mechanism, and any adnexal mass in a MEN1 patient can be considered as a possible malignant NET. Given the rarity of this disease, limited data are available on prognostication and treatment. Management strategies are extrapolated from evidence available in NETs from primaries of other origins. Care should be exercised to remove ovarian NETs en bloc as failure to do so may result in peritoneal seeding and recurrence. Treatment options for advanced disease include debulking surgery, SSAs, TKIs, mTOR inhibitors, PRRT and chemotherapy.

Canagliflozin triggers the FGF23/1,25-dihydroxyvitamin D/PTH axis in healthy volunteers in a randomized crossover study

BACKGROUND

Sodium glucose cotransporter-2 (SGLT2) inhibitors are the most recently approved class of drugs for type 2 diabetes and provide both glycemic efficacy and cardiovascular risk reduction. A number of safety issues have been identified, including treatment-emergent bone fractures. To understand the overall clinical profile, these safety issues must be balanced against an attractive efficacy profile. Our study was designed to investigate pathophysiological mechanisms mediating treatment-emergent adverse effects on bone health.

METHODS

We conducted a single-blind randomized crossover study in hospitalized healthy adults (n = 25) receiving either canagliflozin (300 mg/d) or placebo for 5 days. The primary end-point was the drug-induced change in AUC for plasma intact fibroblast growth factor 23 (FGF23) immunoactivity between 24 and 72 hours.

RESULTS

Canagliflozin administration increased placebo-subtracted mean levels of serum phosphorus (+16%), plasma FGF23 (+20%), and plasma parathyroid hormone (PTH) (+25%), while decreasing the level of 1,25-dihydroxyvitamin D (-10%). There was substantial interindividual variation in the magnitude of each of these pharmacodynamic responses. The increase in plasma FGF23 was correlated with the increase in serum phosphorus, and the decrease in plasma 1,25-dihydroxyvitamin D was correlated with the increase in plasma FGF23.

CONCLUSIONS

Canagliflozin induced a prompt increase in serum phosphorus, which triggers downstream changes in FGF23, 1,25-dihydroxyvitamin D, and PTH, with potential to exert adverse effects on bone health. These pharmacodynamic data provide a foundation for future research to elucidate pathophysiological mechanisms of adverse effects on bone health, with the objective of devising therapeutic strategies to mitigate the drug-associated fracture risk.

TRIAL REGISTRATION

ClinicalTrial.gov (NCT02404870).

FUNDING

Supported by the Intramural Program of NIDDK.

Ketoacidosis associated with SGLT2 inhibitor treatment: Analysis of FAERS data

BACKGROUND

Regulatory agencies have concluded that sodium glucose cotransporter 2 (SGLT2) inhibitors lead to ketoacidosis, but published literature on this point remains controversial.

METHODS

We searched the FDA Adverse Event Reporting System (FAERS) for reports of acidosis in patients treated with canagliflozin, dapagliflozin, or empagliflozin (from the date of each drug's FDA approval until May 15, 2015). We compared the number of SGLT2 inhibitor-related reports to reports of acidosis in patients treated with the 2 most commonly used DPP4 inhibitors: sitagliptin and saxagliptin. We estimated relative risks of acidosis by relating the number of reports to cumulative drug sales (a surrogate for patient exposure).

RESULTS

FAERS contained 259 reports of acidosis (including 192 reports of ketoacidosis) for SGLT2 inhibitors compared with 477 reports of acidosis for DPP4 inhibitors (including 71 reports of ketoacidosis). Based on estimated patient exposure, the overall risk of developing acidosis was ~14-fold higher for SGLT2 inhibitors. Among 51 SGLT2 inhibitor-related reports with quantifiable metabolic information, 20 cases occurred in patients with type 1 diabetes (T1D), 25 in type 2 diabetes (T2D), and 6 in patients with unspecified type of diabetes. After excluding patients with T1D and focusing on patients identified as having T2D, we estimate that SGLT2 inhibitors were associated with ~7-fold increase in developing acidosis. Seventy-one percent had euglycemic ketoacidosis.

CONCLUSIONS

Our results support the FDA's warning that SGLT2 inhibitors lead to ketoacidosis, as evidenced by an increased reporting rate for acidosis above that in a comparator population treated with DPP4 inhibitors.

Normal and Delayed Fracture Healing: Symphony and Cacophony

The incidence of any fracture in the US is estimated to be 2 704 fractures per 100,000 person-years. Approximately 10 percent of these fractures develop complications of healing. The processes that occur during fracture healing mimic the processes that take place in the growth plate during development. The study of fracture healing represents a window to enhance our understanding of the processes of growth and development of bones and its reparative biology. This review is aimed for clinicians evaluating non-unions as an overview of different factors that inhibit fracture healing.

Hormonal responses to non-nutritive sweeteners in water and diet soda

Background

Non-nutritive sweeteners (NNS), especially in form of diet soda, have been linked to metabolic derangements (e.g. obesity and diabetes) in epidemiologic studies. We aimed to test acute metabolic effects of NNS in isolation (water or seltzer) and in diet sodas.

Methods

We conducted a four-period, cross-over study at the National Institutes of Health Clinical Center (Bethesda, Maryland). Thirty healthy adults consumed 355 mL water with 0 mg, 68 mg, 170 mg, and 250 mg sucralose, and 31 individuals consumed 355 mL caffeine-free Diet Rite Cola™, Diet Mountain Dew™ (18 mg sucralose, 18 mg acesulfame-potassium, 57 mg aspartame), and seltzer water with NNS (68 mg sucralose and 41 mg acesulfame-potassium, equivalent to Diet Rite Cola™) in randomized order, prior to oral glucose tolerance tests. Blood samples were collected serially for 130 min. Measures included GLP-1, GIP, glucose, insulin, C-peptide, glucose absorption, gastric emptying, and subjective hunger and satiety ratings.

Results

Diet sodas augmented active GLP-1 (Diet Rite Cola™ vs. seltzer water, AUC, p = 0.039; Diet Mountain Dew™ vs. seltzer water, AUC, p = 0.07), but gastric emptying and satiety were unaffected. Insulin concentrations were nominally higher following all NNS conditions without altering glycemia. Sucralose alone (at any concentration) did not affect metabolic outcomes.

Conclusions

Diet sodas but not NNS in water augmented GLP-1 responses to oral glucose. Whether the trends toward higher insulin concentrations after NNS are of clinical importance remains to be determined. Our findings emphasize the need to test metabolic effects of NNS after chronic consumption.

Trial registration

The data for this manuscript were gathered from clinical trial #NCT01200940.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-016-0129-3) contains supplementary material, which is available to authorized users.

Plasma concentrations of sucralose in children and adults

Sucralose is partially absorbed after oral ingestion, with the majority excreted in the feces. We aimed to measure plasma sucralose concentrations following ingestion of doses reflecting a range of consumption (from one can of diet soda up to multiple sodas over the course of a day) and to compare concentrations in children and adults. Eleven adults (7 females, 4 males) consumed 355 mL water containing 0 mg sucralose (control) or 68, 170, or 250 mg sucralose (equivalent to 1-4 diet sodas). A second group of adults (n=11, 6 females and 5 males) consumed 355 mL Diet Rite Cola™ (68 mg sucralose and 41 mg acesulfame-potassium (ace-K)) or 68 mg sucralose and 41 mg ace-K in seltzer. Beverages were provided at separate visits in randomized order, prior to an oral glucose tolerance test. Eleven children (7 females and 4 males) consumed 0 or 68 mg sucralose in 240 mL water, in an identical study design. Blood was collected before beverage ingestion and serially for 120 min. Sucralose doses (corrected for weight) resulted in similar plasma concentrations in children and adults. Children reached peak concentrations of 145-400 ng/mL after 68 mg (mean 262.3 ± 24.6 ng/mL). Most adults reached similar peak concentrations (200-400 ng/mL after 250 mg (365.6 ± 69.9 ng/mL)) with the exception of two adults (1520 ng/mL and 1557 ng/mL, respectively). Concentrations were comparable whether sucralose was administered in water, combined with ace-K, or in diet soda. Due to their lower body weight and blood volume, children have markedly higher plasma sucralose concentrations after consumption of a typical diet soda, emphasizing the need to determine the clinical implications of sucralose use in children.

Understanding the metabolic and health effects of low-calorie sweeteners: methodological considerations and implications for future research

Consumption of foods, beverages, and packets containing low-calorie sweeteners (LCS) has increased markedly across gender, age, race/ethnicity, weight status, and socio-economic subgroups. However, well-controlled intervention studies rigorously evaluating the health effects of LCS in humans are limited. One of the key questions is whether LCS are indeed a beneficial strategy for weight management and prevention of obesity. The current review discusses several methodological considerations in the design and interpretation of these studies. Specifically, we focus on the selection of study participants, inclusion of an appropriate control, importance of considering habitual LCS exposure, selection of specific LCS, dose and route of LCS administration, choice of study outcomes, and the context and generalizability of the study findings. These critical considerations will guide the design of future studies and thus assist in understanding the health effects of LCS.

Nonnutritive Sweeteners in Breast Milk

Nonnutritive sweeteners (NNS), including saccharin, sucralose, aspartame, and acesulfame-potassium, are commonly consumed in the general population, and all except for saccharin are considered safe for use during pregnancy and lactation. Sucralose (Splenda) currently holds the majority of the NNS market share and is often combined with acesulfame-potassium in a wide variety of foods and beverages. To date, saccharin is the only NNS reported to be found in human breast milk after maternal consumption, while there is no apparent information on the other NNS. Breast milk samples were collected from 20 lactating volunteers, irrespective of their habitual NNS intake. Saccharin, sucralose, and acesulfame-potassium were present in 65% of participants' milk samples, whereas aspartame was not detected. These data indicate that NNS are frequently ingested by nursing infants, and thus prospective clinical studies are necessary to determine whether early NNS exposure via breast milk may have clinical implications.

SGLT2 Inhibitors May Predispose to Ketoacidosis

CONTEXT

Sodium glucose cotransporter 2 (SGLT2) inhibitors are antidiabetic drugs that increase urinary excretion of glucose, thereby improving glycemic control and promoting weight loss. Since approval of the first-in-class drug in 2013, data have emerged suggesting that these drugs increase the risk of diabetic ketoacidosis. In May 2015, the Food and Drug Administration issued a warning that SGLT2 inhibitors may lead to ketoacidosis.

EVIDENCE ACQUISITION

Using PubMed and Google, we conducted Boolean searches including terms related to ketone bodies or ketoacidosis with terms for SGLT2 inhibitors or phlorizin. Priority was assigned to publications that shed light on molecular mechanisms whereby SGLT2 inhibitors could affect ketone body metabolism.

EVIDENCE SYNTHESIS

SGLT2 inhibitors trigger multiple mechanisms that could predispose to diabetic ketoacidosis. When SGLT2 inhibitors are combined with insulin, it is often necessary to decrease the insulin dose to avoid hypoglycemia. The lower dose of insulin may be insufficient to suppress lipolysis and ketogenesis. Furthermore, SGLT2 is expressed in pancreatic α-cells, and SGLT2 inhibitors promote glucagon secretion. Finally, phlorizin, a nonselective inhibitor of SGLT family transporters decreases urinary excretion of ketone bodies. A decrease in the renal clearance of ketone bodies could also increase the plasma ketone body levels.

CONCLUSIONS

Based on the physiology of SGLT2 and the pharmacology of SGLT2 inhibitors, there are several biologically plausible mechanisms whereby this class of drugs has the potential to increase the risk of developing diabetic ketoacidosis. Future research should be directed toward identifying which patients are at greatest risk for this side effect and also to optimizing pharmacotherapy to minimize the risk to patients.

The PTH-Vitamin D-FGF23 axis

Fibroblast growth factor 23 (FGF23) has emerged as an important regulator of phosphate and vitamin D homeostasis. It is important to understand how FGF23 interacts with vitamin D and parathyroid hormone (PTH) in a FGF23-Vitamin D-PTH axis to regulate mineral homeostasis. In this review, we discuss the genomic structure, and transcriptional, translational, and posttranslational regulation of FGF23. We describe its interaction with PTH and vitamin D, disorders of altered FGF23 states, and emerging therapies for diseases of FGF23 based upon these findings. This discussion helps redefine the role of PTH and vitamin D in relation to a complex bone-kidney-parathyroid loop, and points to areas within this complicated field in need of further clarification and research.

Screening for Head and Neck Cancer in Childhood Irradiation

Objective: Except for thyroid disease, no guidelines exist for screening the various sites at risk after a history of childhood irradiation. We sought to develop a formal screening algorithm used to target these high risk patients.

Method: Four patients who each demonstrated 3 or more potentially radiation induced tumors of the head and neck are described. Evidence from the literature describing the relationship between these tumors and childhood irradiation provided the basis for screening recommendations.

Results: Four patients, ages 63 to 76 years, who received childhood irradiation are reported. Three patients had salivary tumors and developed hyperparathyroidism secondary to adenoma. Other tumors included papillary thyroid cancer, benign thyroid nodules, basal cell carcinoma, and ear canal osteoma. We propose an algorithm in evaluating these patients. Initially, patients receive a head and neck physical, baseline laboratories and thyroid ultrasound. Suspicious thyroid lesions or ones greater than 8 mm undergo FNA. An audiogram is recommended and potentially MRI if clinical suspicion exists for acoustic neuroma. If pathology is absent on screening, patients merit follow-up with examination and labs every 1 to 3 years.

Conclusion: Patients with a history of childhood irradiation present a risk for a multitude of head and neck neoplasms and need thorough screening and evaluation. The proposed algorithm provides a comprehensive tool for head and neck cancer screening in this population emphasizing the diversity of manifestations that may present.