Congenital Hyperinsulinism Patients Research Articles

Biomarkers and Diagnostic Thresholds for Congenital Hyperinsulinism.

Congenital Hyperinsulinism (CHI) is associated with inappropriately high levels of C-peptide in the context of hypoglycemia. We aimed to better clarify a diagnostic threshold value of C-peptide for children presenting with CHI. This was a retrospective case-control analysis, examining all hypoglycemia screens, undertaken between 2009 and 2019 at a quaternary paediatrics unit. Plasma C-peptide, insulin, free fatty acid (FFA) and B-hydroxybutyrate (BHOB) concentrations in children diagnosed with CHI were compared with concentrations in children diagnosed with other conditions. All patients requiring hypoglycaemic screens at the quaternary children's hospital were analysed. Median [C-peptide] were statistically significantly different between CHI (147) and non-CHI (72) patients, p < 0.05. The Youden Index indicated that a [C-peptide] value of 291.5 pmol/L would give the greatest optimization of sensitivity (82%) and specificity (99%) for detecting CHI. Median [insulin] differed significantly between the cohorts with a level of 64 pmol/L for CHI patients compared with 0 pmol/L with non-CHI patients (p < 0.01). Median [BOHB] was 0 μmol/L in CHI patients as compared with 2378 μmol/L for non-CHI patients (p < 0.01). Median [FFA] levels were 1910 μmol/L in the non-CHI cohort, compared with 0 in the CHI cohort (p < 0.01). This study suggests that a C-peptide concentration greater than 291.5 pmol/L is diagnostic of CHI in children. C-peptide appears to offer the greatest utility as a biochemical diagnostic test for CHI and could be prioritised for laboratory analysis.

Electroencephalogram features in children with congenital hyperinsulinism treated according to the international protocol in Russian Federation

Congenital hyperinsulinism (CHI) is a rare life-threatening disease characterised by persistent hypoglycaemia as a result of inappropriate insulin secretion, which can lead to irreversible neurological defects in infants. To evaluate neurophysiological characteristics of central nervous system in children with congenital hyperinsulinism treated according to the international protocol in Russian Federation. Our retrospective, prospective cohort study included 73 patients who received treatment for CHI according to the current international protocol at different departments of the Almazov National Medical Research Centre from 2017 to 2022. All patients underwent a comprehensive examination, including electroencephalography (EEG). Among 73 patients with CHI, 35% (23) had focal form of the disease, 65% had non-focal form (49% (39) - diffuse form, 16% (11) - atypical form). All patients with focal form of CHI had a recovery as an outcome.Analysing the EEG data we found that paroxysmal activity was recorded in 23 patients (32%), 50 patients did not have paroxysmal activity (68%). Diffuse changes were observed in 47 patients (64%), whereas 26 patients (36%) were absent of it. By constructing Kaplan-Meier curves we found that the alpha rhythm is formed significantly (p=0.026) earlier in patients with a focal form of CHI. CHI patients treated according to the international guidelines in Russian Federation show rather positive neurological outcome. We established that alpha rhythm earliest formation is associated with focal form of CHI.

PSUN304 CRN04777 an Oral, Nonpeptide SST5-selective Somatostatin Agonist Dose Dependently Suppresses Basal and Stimulated Insulin Secretion

Abstract Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycemia in neonates, infants, and children, and is caused by genetic mutations in the insulin secretion pathway in pancreatic beta-cells. Current medical and surgical treatments are often highly burdensome, only partially effective, and associated with significant morbidity. CRN04777 is a potent orally bioavailable SST5 agonist (EC50=0.41 nM) that is &amp;gt;1300 fold selective over other SST receptor subtypes. CRN04777 has been shown to suppress both glucose- and sulfonylurea (SU)-induced insulin secretion in rats. The latter is a model for the most common known monogenic form of human congenital HI. We report initial results from a randomized, double-blinded, placebo-controlled single ascending dose study evaluating the safety, pharmacokinetics and pharmacodynamics of CRN04777 in 74 healthy volunteers. Endogenous insulin secretion was stimulated using intravenous glucose tolerance tests (IVGTT) or SU challenges in separate cohorts of volunteers. In the IVGTT cohorts, single doses of CRN04777 (0.5-120 mg) were administered after an overnight fast and 1 hour prior to an IV bolus of 300 mg/kg glucose, followed by serial measurements of blood glucose and insulin over 180 minutes. The SU-challenge cohorts received single doses of CRN04777 (30 and 60 mg) one hour after SU administration (5 mg of glibenclamide/glyburide), followed by measurement of the IV glucose infusion rate (GIR) over 8 hours under automated euglycemic clamp conditions (ClampArt®). CRN04777 was orally absorbed (Tmax 1-3 hours) and demonstrated a dose dependent increase in systemic exposures with an apparent terminal elimination t1/2 of approximately 40 hours. Basal insulin secretion was reduced dose-dependently, with a 73% reduction following 120 mg of CRN04777. Likewise, glucose stimulated insulin secretion during the IVGTT (plasma insulin AUC) was reduced dose-dependently by approximately 50% with a parallel doubling of plasma glucose AUC following 120 mg of CRN04777. CRN04777 resulted in dose-dependent reversal of SU-induced insulin secretion, with 79% and 90% reductions in insulin AUC5-180min, respectively, at 30 and 60 mg doses. At the 60 mg dose of CRN04777, no exogenous glucose infusion was needed to prevent SU-induced hypoglycemia. CRN04777 was well tolerated across the dose range evaluated. All adverse events (AEs) were considered mild or moderate and there were no serious AEs. The data from this single-dose, proof-of-concept study show that the selective SST5 agonist CRN04777 is well tolerated after oral administration in healthy volunteers, is suitable for once daily dosing and suppresses insulin secretion under basal and stimulated conditions, including in a pharmacologic model of congenital HI. Multiple ascending dose evaluations in healthy volunteers are underway to support future studies in congenital HI patients. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Somatostatin receptors in congenital hyperinsulinism: Biology to bedside.

Congenital hyperinsulinism (CHI), although a rare disease, is an important cause of severe hypoglycemia in early infancy and childhood, causing preventable morbidity and mortality. Prompt diagnosis and appropriate treatment is necessary to prevent hypoglycaemia mediated brain damage. At present, the medical treatment of CHI is limited to diazoxide as first line and synthetic somatostatin receptor ligands (SRLs) as second line options; therefore understanding somatostatin biology and treatment perspectives is important. Under healthy conditions, somatostatin secreted from pancreatic islet δ-cells reduces insulin release through somatostatin receptor induced cAMP-mediated downregulation and paracrine inhibition of β- cells. Several SRLs with extended duration of action are now commercially available and are being used off-label in CHI patients. Efficacy remains variable with the present generation of SRLs, with treatment effect often being compromised by loss of initial response and adverse effects such as bowel ischaemia and hepatobiliary dysfunction. In this review we have addressed the biology of the somatostatin system contexualised to CHI. We have discussed the clinical use, limitations, and complications of somatostatin agonists and new and emerging therapies for CHI.

Variation in Glycemic Outcomes in Focal Forms of Congenital Hyperinsulinism-The UK Perspective.

ContextIn focal congenital hyperinsulinism (CHI), localized clonal expansion of pancreatic β-cells causes excess insulin secretion and severe hypoglycemia. Surgery is curative, but not all lesions are amenable to surgery.ObjectiveWe describe surgical and nonsurgical outcomes of focal CHI in a national cohort.MethodsPatients with focal CHI were retrospectively reviewed at 2 specialist centers, 2003-2018.ResultsOf 59 patients with focal CHI, 57 had heterozygous mutations in ABCC8/KCNJ11 (51 paternally inherited, 6 de novo). Fluorine-18 L-3,4 dihydroxyphenylalanine positron emission tomography computed tomography scan identified focal lesions in 51 patients. In 5 patients, imaging was inconclusive; the diagnosis was established by frozen section histopathology in 3 patients, a lesion was not identified in 1 patient, and 1 declined surgery. Most patients (n = 56) were unresponsive to diazoxide, of whom 33 were unresponsive or partially responsive to somatostatin receptor analog (SSRA) therapy. Fifty-five patients underwent surgery: 40 had immediate resolution of CHI, 10 had persistent hypoglycemia and a focus was not identified on biopsy in 5. In the 10 patients with persistent hypoglycemia, 7 underwent further surgery with resolution in 4 and ongoing hypoglycemia requiring SSRA in 3. Nine (15% of cohort) patients (1 complex surgical access; 4 biopsy negative; 4 declined surgery) were managed conservatively; medication was discontinued in 8 children at a median (range) age 2.4 (1.5-7.7) years and 1 remains on SSRA at 16 years with improved fasting tolerance and reduction in SSRA dose.ConclusionDespite a unifying genetic basis of disease, we report inherent heterogeneity in focal CHI patients impacting outcomes of both surgical and medical management.

ATP-Sensitive Potassium Channels in Hyperinsulinism and Type 2 Diabetes: Inconvenient Paradox or New Paradigm?

Secretion of insulin from pancreatic β-cells is complex, but physiological glucose-dependent secretion is dominated by electrical activity, in turn controlled by ATP-sensitive potassium (KATP) channel activity. Accordingly, loss-of-function mutations of the KATP channel Kir6.2 (KCNJ11) or SUR1 (ABCC8) subunit increase electrical excitability and secretion, resulting in congenital hyperinsulinism (CHI), whereas gain-of-function mutations cause underexcitability and undersecretion, resulting in neonatal diabetes mellitus (NDM). Thus, diazoxide, which activates KATP channels, and sulfonylureas, which inhibit KATP channels, have dramatically improved therapies for CHI and NDM, respectively. However, key findings do not fit within this simple paradigm: mice with complete absence of β-cell KATP activity are not hyperinsulinemic; instead, they are paradoxically glucose intolerant and prone to diabetes, as are older human CHI patients. Critically, despite these advances, there has been little insight into any role of KATP channel activity changes in the development of type 2 diabetes (T2D). Intriguingly, the CHI progression from hypersecretion to undersecretion actually mirrors the classical response to insulin resistance in the progression of T2D. In seeking to explain the progression of CHI, multiple lines of evidence lead us to propose that underlying mechanisms are also similar and that development of T2D may involve loss of KATP activity.

Possible new strategies for the treatment of congenital hyperinsulinism

Objective Congenital hyperinsulinism (CHI) is a rare disease characterized by persistent hypoglycemia as a result of inappropriate insulin secretion, which can lead to irreversible neurological defects in infants. Poor efficacy and strong adverse effects of the current medications impede successful treatment. The aim of the study was to investigate new approaches to silence β-cells and thus attenuate insulin secretion. Research design and methods In the scope of our research, we tested substances more selective and more potent than the gold standard diazoxide that also interact with neuroendocrine ATP-sensitive K+ (KATP) channels. Additionally, KATP channel-independent targets as Ca2+-activated K+ channels of intermediate conductance (KCa3.1) and L-type Ca2+ channels were investigated. Experiments were performed using human islet cell clusters isolated from tissue of CHI patients (histologically classified as pathological) and islet cell clusters obtained from C57BL/6N (WT) or SUR1 knockout (SUR1-/-) mice. The cytosolic Ca2+ concentration ([Ca2+]c) was used as a parameter for the pathway regulated by electrical activity and was determined by fura-2 fluorescence. The mitochondrial membrane potential (ΔΨ) was determined by rhodamine 123 fluorescence and single channel currents were measured by the patch-clamp technique. Results The selective KATP channel opener NN414 (5 µM) diminished [Ca2+]c in isolated human CHI islet cell clusters and WT mouse islet cell clusters stimulated with 10 mM glucose. In islet cell clusters lacking functional KATP channels (SUR1-/-) the drug was without effect. VU0071063 (30 µM), another KATP channel opener considered to be selective, lowered [Ca2+]c in human CHI islet cell clusters. The compound was also effective in islet cell clusters from SUR1-/- mice, showing that [Ca2+]c is influenced by additional effects besides KATP channels. Contrasting to NN414, the drug depolarized ΔΨ in murine islet cell clusters pointing to severe interference with mitochondrial metabolism. An opener of KCa3.1 channels, DCEBIO (100 µM), significantly decreased [Ca2+]c in SUR1-/- and human CHI islet cell clusters. To target L-type Ca2+ channels we tested two already approved drugs, dextromethorphan (DXM) and simvastatin. DXM (100 µM) efficiently diminished [Ca2+]c in stimulated human CHI islet cell clusters as well as in stimulated SUR1-/- islet cell clusters. Similar effects on [Ca2+]c were observed in experiments with simvastatin (7.2 µM). Conclusions NN414 seems to provide a good alternative to the currently used KATP channel opener diazoxide. Targeting KCa3.1 channels by channel openers or L-type Ca2+ channels by DXM or simvastatin might be valuable approaches for treatment of CHI caused by mutations of KATP channels not sensitive to KATP channel openers.

68Ga-NODAGA-Exendin-4 PET/CT Improves the Detection of Focal Congenital Hyperinsulinism.

Surgery with curative intent can be offered to congenital hyperinsulinism (CHI) patients, provided that the lesion is focal. Radiolabeled exendin-4 specifically binds the glucagonlike peptide 1 receptor on pancreatic β-cells. In this study, we compared the performance of 18F-DOPA PET/CT, the current standard imaging method for CHI, and PET/CT with the new tracer 68Ga-NODAGA-exendin-4 in the preoperative detection of focal CHI. Methods: Nineteen CHI patients underwent both 18F-DOPA PET/CT and 68Ga-NODAGA-exendin-4 PET/CT before surgery. The images were evaluated in 3 settings: a standard clinical reading, a masked expert reading, and a joint reading. The target (lesion)-to-nontarget (normal pancreas) ratio was determined using SUVmax Image quality was rated by pediatric surgeons in a questionnaire. Results: Fourteen of 19 patients having focal lesions underwent surgery. On the basis of clinical readings, the sensitivity of 68Ga-NODAGA-exendin-4 PET/CT (100%; 95% CI, 77%-100%) was higher than that of 18F-DOPA PET/CT (71%; 95% CI, 42%-92%). Interobserver agreement between readings was higher for 68Ga-NODAGA-exendin-4 than for 18F-DOPA PET/CT (Fleiss κ = 0.91 vs. 0.56). 68Ga-NODAGA-exendin-4 PET/CT provided significantly (P = 0.021) higher target-to-nontarget ratios (2.02 ± 0.65) than did 18F-DOPA PET/CT (1.40 ± 0.40). On a 5-point scale, pediatric surgeons rated 68Ga-NODAGA-exendin-4 PET/CT as superior to 18F-DOPA PET/CT. Conclusion: For the detection of focal CHI, 68Ga-NODAGA-exendin-4 PET/CT has higher clinical sensitivity and better interobserver correlation than 18F-DOPA PET/CT. Better contrast and image quality make 68Ga-NODAGA-exendin-4 PET/CT superior to 18F-DOPA PET/CT in surgeons' intraoperative quest for lesion localization.

Selective Somatostatin 5 (SST5) and Somatostatin 2 (SST2) Nonpeptide Agonists Potently Suppress Glucose- and Tolbutamide-Stimulated Dynamic Insulin Secretion From Isolated Human Islets

Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycemia in newborns and infants and arises from dysregulated insulin secretion. Rapid recognition and treatment are vital to prevent seizures, permanent developmental delays, coma, or even death. Very few medical options exist to treat congenital HI patients: the KATP channel activator diazoxide, the injectable somatostatin receptor peptide agonists octreotide and lanreotide, or chronic glucose infusions. However, side effects and/or limited efficacy render these therapies inadequate for many patients.Somatostatin is a 14-amino acid peptide hormone with a broad spectrum of biological actions, which are regulated through five somatostatin receptor subtypes (SST1-SST5). Somatostatin’s common physiological role is to down-regulate secretion of other hormones in various tissues. Its role in the maintenance of euglycemia is to regulate insulin and glucagon secretion from pancreatic β- and α-cells, respectively. Somatostatin regulates insulin secretion by decreasing the intracellular levels of cAMP, inhibition of voltage-gated calcium channels (VGCC), activation of the G protein-activated inward rectifier K+ channel (GIRK), and direct inhibition of insulin exocytosis.Several studies have evaluated the effect of somatostatin, somatostatin peptide analogs, and a limited number of nonpeptide somatostatin receptor agonists on insulin secretion in static assays using isolated human islets. However, the lack of highly selective agonists has made the interpretation of the contribution of SST receptor sub-types difficult to discern. Our programs for the treatment of hyperinsulinism, acromegaly, and other indications have led to the development of selective nonpeptide SST2, SST3, SST4, and SST5 agonists, possessing EC50s < 1 nM in cell-based assays of receptor activation and selectivity > 130 times over the other members of the family. The ability of these selective nonpeptide agonists to regulate glucose- and tolbutamide-stimulated dynamic insulin secretion from human islets was evaluated using a perifusion system (Biorep, FL).We found that selective SST2 and SST5 agonists potently suppressed dynamic insulin secretion in contrast to SST3 or SST4 selective agonists. Importantly, SST5 agonists were shown to have a greater effect than selective SST2 agonists or diazoxide, demonstrating their potential utility in human conditions such as congenital HI. In addition, SST5 activation is also known to have a smaller effect on glucagon secretion and is also less prone to agonist-driven desensitization than SST2 activation. Taken together, these studies support our program to identify, characterize, and develop potent, nonpeptide, orally-bioavailable, selective SST5 agonists with appropriate pharmaceutical and safety characteristics for the treatment of congenital HI.

Clinical and genetic characteristics of patients with congenital hyperinsulinism in 21 non-consanguineous families from Serbia.

Persistent hypoglycaemia in newborns and infants is most commonly caused by congenital hyperinsulinism (CHI). Most CHI studies report outcomes in children from both consanguineous and non-consanguineous families which can affect the phenotype-genotype analysis. The aim of this study was to analyze characteristics of patients with CHI in 21 non-consanguineous families from Serbia. This retrospective cohort study included a total of 21 patients with CHI treated in the Mother and Child Healthcare Institute of Serbia during the past 20 years. The prevalence of macrosomia at birth was very low in our cohort (4.8%). Median age at presentation was 6 days, with seizures as the presenting symptom in 76% of patients. Only four patients (19%) were diazoxide unresponsive, and eventually underwent pancreatectomy. Genetic testing was performed in 15 patients and genetic diagnosis was confirmed in 60%, with all patients being heterozygous for detected mutations. The ABCC8 gene mutations were detected in 55.6%, GLUD1 in three patients (33.3%) with HIHA syndrome and one patient had HNF4A gene mutation and unusual prolonged hyperglycaemia lasting 6 days after diazoxide cessation. Neurodevelopmental deficits persisted in 33% of patients.Conclusion: This is the first study regarding CHI patients in Serbia. It suggests that in countries with low consanguinity rate, majority of CHI patients are diazoxide responsive. The most common mutations were heterozygous ABCC8, followed by GLUD1 and HNF4A mutations, suggesting the potential benefit of population-tailored genetic analysis approach, targeting the mutations causing CHI via dominant inheritance model in regions with low consanguinity rates. What is Known: • Persistent hypoglycaemia during infancy and early childhood is most commonly caused by congenital hyperinsulinism (CHI). • Consanguinity is a very important factor regarding the genetics and phenotype of CHI, increasing the risk of autosomal recessive genetic disorders, including the severe, diazoxide-unresponsive forms caused by recessive inactivating mutations in ABCC8 and KCNJ11. What is New: • Results of the present study which included CHI patients from 21 non-consanguineous families suggest that in countries with low consanguinity rates, majority of CHI patients can be diazoxide responsive, with most common mutations being heterozygous ABCC8, followed by GLUD1 and HNF4A mutations. • Unusually prolonged hyperglycaemic reaction to diazoxide treatment in a patient with HNF4A mutation was also described in the present study.

A Sensitive Plasma Insulin Immunoassay to Establish the Diagnosis of Congenital Hyperinsulinism.

BackgroundThe diagnosis of congenital hyperinsulinism (CHI) may be hampered by a plasma (p-) insulin detection limit of 12–18 pmol/L (2–3 mU/L).ObjectiveTo evaluate the diagnostic performance of a sensitive insulin immunoassay and to find the optimal p-insulin cut-off for the diagnosis of CHI.MethodsDiagnostic fasting tests, performed without medication or i.v.-glucose, were investigated in children with a clinical diagnosis of CHI, or idiopathic ketotic hypoglycemia (IKH). The CHI diagnosis was either clinical or by the alternative, p-insulin-free criteria; hypoglycemia plus disease-causing genetic mutations and/or CHI-compatible pancreatic histopathology. We included diagnostic p-insulin samples with simultaneous p-glucose <3.2 mmol/L and used a sensitive insulin assay (Cobas e411 immunoassay analyzer; lower detection limit 1.2 pmol/L; normal range 15.1–147.1 pmol/L). Receiver operating characteristics area under the curve (ROC AUC) values and optimal cut-offs were analyzed for the performance of p-insulin to diagnose CHI.ResultsIn 61 CHI patients, the median (range) p-insulin was 76.5 (17–644) pmol/L compared to 1.5 (1.5–7.7) pmol/L in IKH patients (n=15). The ROC AUC was 1.0 for the diagnosis of CHI defined both by the clinical diagnosis (n=61) and by alternative criteria (n=57). The optimal p-insulin cut-offs were 12.3 pmol/L, and 10.6 pmol/L, at p-glucose <3.2 mmol/L (n=61), and <3.0 mmol/L (n=49), respectively.ConclusionsThe sensitive insulin assay performed excellent in diagnosing CHI with optimal p-insulin cut-offs at 12.3 pmol/L (2.0 mU/L), and 10.6 pmol/L (1.8 mU/L), at p-glucose <3.2 mmol/L, and <3.0 mmol/L, respectively. A sensitive insulin assay may serve to simplify the diagnosis of CHI.

Long-Term Outcome and Treatment in Persistent and Transient Congenital Hyperinsulinism: A Finnish Population-Based Study.

ContextThe management of congenital hyperinsulinism (CHI) has improved.ObjectiveTo examine the treatment and long-term outcome of Finnish patients with persistent and transient CHI (P-CHI and T-CHI).DesignA population-based retrospective study of CHI patients treated from 1972 to 2015.Patients106 patients with P-CHI and 132 patients with T-CHI (in total, 42 diagnosed before and 196 after year 2000) with median follow-up durations of 12.5 and 6.2 years, respectively.Main Outcome MeasuresRecovery, diabetes, pancreatic exocrine dysfunction, neurodevelopment.ResultsThe overall incidence of CHI (n = 238) was 1:11 300 live births (1972-2015). From 2000 to 2015, the incidence of P-CHI (n = 69) was 1:13 500 and of T-CHI (n = 127) 1:7400 live births. In the 21st century P-CHI group, hyperinsulinemic medication was initiated and normoglycemia achieved faster relative to earlier. Of the 74 medically treated P-CHI patients, 68% had discontinued medication. Thirteen (12%) P-CHI patients had partial pancreatic resection and 19 (18%) underwent near-total pancreatectomy. Of these, 0% and 84% developed diabetes and 23% and 58% had clinical pancreatic exocrine dysfunction, respectively. Mild neurological difficulties (21% vs 16%, respectively) and intellectual disability (9% vs 5%, respectively) were as common in the P-CHI and T-CHI groups. However, the 21st century P-CHI patients had significantly more frequent normal neurodevelopment and significantly more infrequent diabetes and pancreatic exocrine dysfunction compared with those diagnosed earlier.ConclusionsOur results demonstrated improved treatment and long-term outcome in the 21st century P-CHI patients relative to earlier.

The use of long-acting somatostatin analogs in congenital hyperinsulinism

Children with congenital hyperinsulinism (CHI), a severe orphan disease, are still one of the most demanding patients in the endocrinology practice. The use of first- and second-line drugs is not always effective and has a number of restrictions. Lanreotide - long-acting somatostatin - represents an alternative insulinostatic therapy. The main advantage of lanreotide is stable concentration of the drug in the blood that enables minimizing the number of injections. However, the experience of using lanreotide in the treatment of CHI is limited to small groups of patients. There is also a problem of the absence of a standardized regimen in clinical practice; and the calculator for evaluating the initial effective drug dose is needed.AIM of the study is to evaluate the effectiveness and safety of lanreotide therapy in the treatment of CHI in children. An open single-center observational study was conducted on the basis of Endocrinology Research Centre. The study included diazoxide-unresponsive pediatric patients with CHI who were initially treated with octreotide in different modes: multiple daily subcutaneous injections or continuous subcutaneous infusion via pumps. The indicators of the effectiveness and safety of the lanreotide therapy were evaluated shortly after the first injection and lately on a regular visit after further injections. The study group included 12 patients. Persistent euglycaemia was achieved in 67% of the subjects (8/12). Complete effectiveness of the therapy was observed in 8/12 patients (67%), partial - in 3/12 (25%), and lack of effectiveness - in 1/12 of the patient (8%). The age of the patients at the time of lanreotide administration was 6 months (5; 15). According to the study, the most effective dose of lanreotide is 3.5-5.5 mg/ kg/ month. There were no significant side effects observed. The use of lanreotide in patients with diazoxide-resistant congenital hyperinsulinism was effective and safe in the vast majority of the patients. Moreover, we were able to calculate the effective dosage of lanreotide in CHI patients which fulfilled the clinical demand.

Risk Factors for Adverse Neurodevelopment in Transient or Persistent Congenital Hyperinsulinism.

ObjectiveAim was to identify hypotheses why adverse neurodevelopment still occurs in children with transient or persistent hyperinsulinism despite improvements in long-term treatment options during the last decades.Material and MethodsA retrospective review of 87 children with transient (n=37) or persistent congenital hyperinsulinism (CHI) (n=50) was conducted at the University Children’s Hospital Duesseldorf, Germany. Possible risk factors for neurodevelopmental sequelae due to hypoglycemia were analyzed with a focus on the first days after onset of disease.ResultsMedian age at follow-up was 7 years (IQR 8). Adverse neurodevelopmental outcome was seen in 34.5% (n=30) of all CHI patients. Fifteen had mildly abnormal neurodevelopment and 15 had a severe hypoglycemic brain injury. In univariate analysis, mildly abnormal neurodevelopment was associated with the diagnosis of persistent CHI (odds ratio (OR) 8.3; p=0.004) and higher birth weight (mean difference 1049 g; p<0.001). Severe hypoglycemic brain injury was associated with the diagnosis of persistent CHI (OR 5.1; p=0.013), being born abroad (OR 18.3; p<0.001) or in a lower-level maternity hospital (OR 4.8; p=0.039), and of note history of hypoglycemic seizures (OR 13.0; p=<0.001), and a delay between first symptoms of hypoglycemia and first blood glucose measurement/initiation of treatment (OR 10.7; p<0.001). Children with severe hypoglycemic brain injury had lower recorded blood glucose (mean difference -8.34 mg/dl; p=0.022) and higher birth weight than children with normal development (mean difference 829 g; p=0.012). In multivariate binary logistic regression models, lowest blood glucose <20 mg/dl (OR 134.3; p=0.004), a delay between initial symptoms and first blood glucose measurement/initiation of treatment (OR 71.7; p=0.017) and hypoglycemic seizures (OR 12.9; p=0.008) were positively correlated with severe brain injury. Analysis showed that the odds for brain injury decreased by 15% (OR 0.85; p=0.035) if the blood glucose increased by one unit.ConclusionWhile some risk factors for adverse outcome in CHI are not influenceable, others like lowest recorded blood glucose values <20 mg/dl, hypoglycemic seizures, and insufficiently—or even untreated hypoglycemia can be avoided. Future guidelines for management of neonatal hypoglycemia should address this by ensuring early identification and immediate treatment with appropriate escalation steps.

Possible New Strategies for the Treatment of Congenital Hyperinsulinism.

ObjectiveCongenital hyperinsulinism (CHI) is a rare disease characterized by persistent hypoglycemia as a result of inappropriate insulin secretion, which can lead to irreversible neurological defects in infants. Poor efficacy and strong adverse effects of the current medications impede successful treatment. The aim of the study was to investigate new approaches to silence β-cells and thus attenuate insulin secretion.Research Design and MethodsIn the scope of our research, we tested substances more selective and more potent than the gold standard diazoxide that also interact with neuroendocrine ATP-sensitive K+ (KATP) channels. Additionally, KATP channel-independent targets as Ca2+-activated K+ channels of intermediate conductance (KCa3.1) and L-type Ca2+ channels were investigated. Experiments were performed using human islet cell clusters isolated from tissue of CHI patients (histologically classified as pathological) and islet cell clusters obtained from C57BL/6N (WT) or SUR1 knockout (SUR1-/-) mice. The cytosolic Ca2+ concentration ([Ca2+]c) was used as a parameter for the pathway regulated by electrical activity and was determined by fura-2 fluorescence. The mitochondrial membrane potential (ΔΨ) was determined by rhodamine 123 fluorescence and single channel currents were measured by the patch-clamp technique.ResultsThe selective KATP channel opener NN414 (5 µM) diminished [Ca2+]c in isolated human CHI islet cell clusters and WT mouse islet cell clusters stimulated with 10 mM glucose. In islet cell clusters lacking functional KATP channels (SUR1-/-) the drug was without effect. VU0071063 (30 µM), another KATP channel opener considered to be selective, lowered [Ca2+]c in human CHI islet cell clusters. The compound was also effective in islet cell clusters from SUR1-/- mice, showing that [Ca2+]c is influenced by additional effects besides KATP channels. Contrasting to NN414, the drug depolarized ΔΨ in murine islet cell clusters pointing to severe interference with mitochondrial metabolism. An opener of KCa3.1 channels, DCEBIO (100 µM), significantly decreased [Ca2+]c in SUR1-/- and human CHI islet cell clusters. To target L-type Ca2+ channels we tested two already approved drugs, dextromethorphan (DXM) and simvastatin. DXM (100 µM) efficiently diminished [Ca2+]c in stimulated human CHI islet cell clusters as well as in stimulated SUR1-/- islet cell clusters. Similar effects on [Ca2+]c were observed in experiments with simvastatin (7.2 µM).ConclusionsNN414 seems to provide a good alternative to the currently used KATP channel opener diazoxide. Targeting KCa3.1 channels by channel openers or L-type Ca2+ channels by DXM or simvastatin might be valuable approaches for treatment of CHI caused by mutations of KATP channels not sensitive to KATP channel openers.

Clinical Efficacy Evaluation of Sirolimus in Congenital Hyperinsulinism.

Background Congenital hyperinsulinism (CHI) is a rare and life-threatening genetic disorder. Sirolimus as a mammalian target of rapamycin inhibitor may be helpful in patients with CHI who do not respond well to other treatments including diazoxide and octreotide. However, the safety and efficacy of this therapy are still unclear. This study aimed to evaluate the potential therapeutic effects of sirolimus in CHI patients with mutations in the ABCC8 and KCNJ11 genes. Methods During the period of this follow-up study, every child with a confirmed diagnosis of unresponsive CHI underwent genetic evaluation. Among those who had positive genetic testing, six families agreed to participate in this study. The participants were evaluated for ABCC8, KCNJ11, or HNF4α gene mutations by polymerase chain reaction (PCR) sequencing. The participants who were unresponsive to diazoxide and octreotide therapy received 0.5 mg/m2/d of sirolimus, and the dose was gradually increased until a serum concentration of 5–15 ng/ml was achieved. Then, the participants were followed up for any possible complications. Results Among the study participants, only one neonate was completely free of hypoglycemia after one year of follow-up, whereas three others experienced a partial reduction in hypoglycemic episodes over six months. One neonate underwent pancreatectomy despite receiving sirolimus. The oldest participant with a mutation in the ABCC8 gene responded well to sirolimus therapy after surgery and remained asymptomatic for 18 months. Conclusion This study suggested that sirolimus therapy needs further evaluation to determine which patients will benefit the most. The genetic basis of CHI may have possible implications for determining the patient's response.

MON-111 Plasma Insulin Measured with a Sensitive Immunoassay May Establish the Diagnosis of Congenital Hyperinsulinism Without Further Testing

Background: The diagnosis of congenital hyperinsulinism (CHI) is often hampered by a plasma insulin (p-insulin) detection limit of 2-3 mU/L (14-21 pmol/L) by RIA methods. Objective: To evaluate the diagnostic performance of a sensitive immunoassay for p-insulin and to find the optimal p-insulin cut-off for CHI versus other conditions with hypoglycaemia. Design: Single centre retrospective cohort study. Methods: Diagnostic tests with no medication, no i.v. glucose and under fasting conditions were performed in children with a clinical diagnosis of CHI. P-insulin concentrations determined at simultaneous p-glucose concentrations at least <3.2 mmol/L (57.5 mg/dL) were included in the analysis (n=61).The diagnosis of CHI was either clinical (n=61) or by gold standard criteria: hypoketotic hypoglycaemia plus disease-causing genetic mutations and/or diffuse, focal or atypical pancreatic histopathology (n=57). Samples from 15 children with idiopathic ketotic hypoglycaemia (IKH, diagnosis by exclusion, p-ketones >1.5 mmol/L during hypoglycaemia) were used as controls.P-insulin was measured by the high-sensitive assay (Cobas e411 immunoassay analyzer); lower detection limit 1.4 pmol/L (0.2 mU/L); normal range 18-173 pmol/L (2.57-24.7 mU/L). Concentrations <18 pmol/L were considered suppressed; ≥18 pmol/L un-suppressed.Receiver operating characteristics (ROC) curves with determination of area under the curve (AUC) values were performed for the diagnostic performance of p-insulin in the diagnosis of CHI. Results: In the 61 samples from CHI patients, the median (range) p-insulin was un-suppressed in all diagnostic samples [90; 20-758 pmol/L (12.9; 2.9-109.1 mU/L)], while p-insulin was suppressed in all 15 samples from IKH patients [1.5; 1.5-9 pmol/L (0.21; 0.21-1.3 mU/L)]. The ROC AUC was 1.0 (95%CI. 1.0-1.0) for the diagnosis of CHI defined both by the clinic and by gold standard. The optimal p-insulin cut-off was 14.5 pmol/L (2.1 mU/L) or 12.5 pmol/L (1.8 mU/L), for CHI patients by use of a simultaneous p-glucose cut-off of <3.2 mmol/L (57.5 mg/dL; n=61), or 3.0 mmol/L (55 mg/dL; n=49), respectively. Conclusions: The sensitive insulin assay performed excellent in diagnosing CHI with a ROC AUC of 1.0. The use of a p-insulin cut-off of 13 pmol/L (1.86 mU/L) during a diagnostic hypoketotic hypoglycaemia test may establish the diagnosis of CHI without further diagnostic testing.

Clinical Management and Gene Mutation Analysis of Children with Congenital Hyperinsulinism in South China

Objective:To explore the clinical presentation and molecular genetic characteristics of a cohort of congenital hyperinsulinism (CHI) patients from southern China and also to explore the most appropriate therapeutic approaches.Methods:We retrospectively reviewed a cohort of 65 children with CHI. Mutational analysis was performed for KCNJ11 and ABCC8 genes. The GLUD1 gene was sequenced in patients with hyperammonaemia. GCK gene sequencing was performed in those patients with no mutation identified in the ABCC8, KCNJ11 or GLUD1 genes.Results:ABCC8 mutations were identified in 16 (25%) of the cohort, GLUD1 mutations were identified in five children, and no KCNJ11 or GCK mutations were identified. Moreover, some unique features of ABCC8 gene mutations in southern Chinese CHI patients were found in this study. The most common mutation was a deletion/insertion mutation p.Thr1042GlnfsX75 was found in five unrelated patients, which possibly represents a relatively common mutation in southern China. Five novel ABCC8 mutations were detected. The mutations were p.Phe5SerfsX72, p.Gln273ArgfsX85, p.Leu724del, p.Asp1447Gly and IVS 25-1G>T. Five compound heterozygous mutations of ABCC8 gene were identified in this study, and three of these patients were diazoxide-responsive. Forty patients were diazoxide-responsive, 13 patients were diazoxide-unresponsive and 12 patients received dietary treatment only. A pancreatectomy was performed in 10 patients who were unresponsive to medical treatment.Conclusion:To the best of our knowledge, this is the first study of CHI in south China. Mutations in ABCC8 are the most common causes of CHI in this cohort. Diazoxide and dietary treatment were effective in most patients. Multicentre studies are necessary to obtain the long-term follow-up characteristics of such patients at a national level.

Sirolimus: efficacy and complications in children with hyperinsulinemic hypoglycemia: A 5-year follow-up study

Introduction Sirolimus, a mammalian target of rapamycin inhibitor, has been used in congenital hyperinsulinism (CHI) unresponsive to diazoxide and octreotide. Reported response to sirolimus is variable, with high incidence of adverse effects. To the best of our knowledge, we report the largest group of CHI patients treated with sirolimus followed for the longest period to date. Methods Retrospective study of CHI patients treated with sirolimus in a tertiary service and review of the 15 publications reporting CHI patients treated with mammalian target of rapamycin inhibitors. Comparison was made between the findings of this study with those previously published. Results Twenty-two CHI patients treated with sirolimus were included in this study. Twenty showed partial response, one showed complete response, and one was unresponsive. Five of the partially/fully responsive patients had compound heterozygous ABCC8 mutations and five had heterozygous ABCC8 mutations. A total of 86.4% (19/22) developed complications, with infection being the most frequent (17/22), of which 11 were of bacterial etiology, followed by persistent diarrhea (3/22) and hyperglycemia (2/22). Seventeen patients stopped sirolimus: 13 from infections; 2 from hyperglycemia; and 2 from alternative treatment (lanreotide) response. Compared with data previously published, our study identified a higher number of partially sirolimus-responsive CHI cases, although the high rate of complications while on this medication limited its potential usefulness. Conclusion Sirolimus candidates must be carefully selected given its frequent and potentially life-threatening side effects. Its use as a short-term, last-resort therapy until normoglycemia is achieved with other agents such as lanreotide could avoid pancreatectomy. Further studies evaluating the use of sirolimus in patients with CHI are required.

Central venous catheter-associated thrombosis in children with congenital hyperinsulinism

SummaryCongenital hyperinsulinism (CHI) is an important cause of severe hypoglycaemia in infancy. To correct hypoglycaemia, high concentrations of dextrose are often required through a central venous catheter (CVC) with consequent risk of thrombosis. We describe a series of six cases of CHI due to varying aetiologies from our centre requiring CVC for the management of hypoglycaemia, who developed thrombosis in association with CVC. We subsequently analysed the incidence and risk factors for CVC-associated thrombosis, as well as the outcomes of enoxaparin prophylaxis. The six cases occurred over a 3-year period; we identified an additional 27 patients with CHI who required CVC insertion during this period (n = 33 total), and a separate cohort of patients with CHI and CVC who received enoxaparin prophylaxis (n = 7). The incidence of CVC-associated thrombosis was 18% (6/33) over the 3 years, a rate of 4.2 thromboses/1000 CVC days. There was no difference in the frequency of genetic mutations or focal CHI in those that developed thromboses. However, compound heterozygous/homozygous potassium ATP channel mutations correlated with thrombosis (R2 = 0.40, P = 0.001). No difference was observed in CVC duration, high concentration dextrose or glucagon infused through the CVC. In patients receiving enoxaparin prophylaxis, none developed thrombosis or bleeding complications. The characteristics of these patients did not differ significantly from those with thrombosis not on prophylaxis. We therefore conclude that CVC-associated thrombosis can occur in a significant proportion (18%) of patients with CHI, particularly in severe CHI, for which anticoagulant prophylaxis may be indicated.Learning points:CVC insertion is one of the most significant risk factors for thrombosis in the paediatric population.Risk factors for CVC-associated thrombosis include increased duration of CVC placement, malpositioning and infusion of blood products.To our knowledge, this is the first study to evaluate CVC-associated thrombosis in patients with congenital hyperinsulinism (CHI).The incidence of CVC-associated thrombosis development is significant (18%) in CHI patients and higher compared to other neonates with CVC. CHI severity may be a risk factor for thrombosis development.Although effective prophylaxis for CVC-associated thrombosis in infancy is yet to be established, our preliminary experience suggests the safety and efficacy of enoxoaparin prophylaxis in this population and requires on-going evaluation.