Laparoscopic diagnosis and cure of hyperinsulinism in two cases of focal adenomatous hyperplasia in infancy

Congenital Hyperinsulinism Caused by Mutations in ABCC8 Gene Associated with Early-Onset Neonatal Hypoglycemia: Genetic Heterogeneity Correlated with Phenotypic Variability

Congenital hyperinsulinism (CHI) is a rare disorder of glucose metabolism and is the most common cause of severe and persistent hypoglycemia (hyperinsulinemic hypoglycemia, HH) in the neonatal period and childhood. Most cases are caused by mutations in the ABCC8 and KCNJ11 genes that encode the ATP-sensitive potassium channel (KATP). We present the correlation between genetic heterogeneity and the variable phenotype in patients with early-onset HH caused by ABCC8 gene mutations. In the first patient, who presented persistent severe hypoglycemia since the first day of life, molecular genetic testing revealed the presence of a homozygous mutation in the ABCC8 gene [deletion in the ABCC8 gene c.(2390+1_2391-1)_(3329+1_3330-1)del] that correlated with a diffuse form of hyperinsulinism (the parents being healthy heterozygous carriers). In the second patient, the onset was on the third day of life with severe hypoglycemia, and genetic testing identified a heterozygous mutation in the ABCC8 gene c.1792C>T (p.Arg598*) inherited on the paternal line, which led to the diagnosis of the focal form of hyperinsulinism. To locate the focal lesions, (18)F-DOPA (3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine) positron emission tomography/computed tomography (PET/CT) was recommended (an investigation that cannot be carried out in the country), but the parents refused to carry out the investigation abroad. In this case, early surgical treatment could have been curative. In addition, the second child also presented secondary adrenal insufficiency requiring replacement therapy. At the same time, she developed early recurrent seizures that required antiepileptic treatment. We emphasize the importance of molecular genetic testing for diagnosis, management and genetic counseling in patients with HH.

Minimally invasive hepatopancreatic and biliary surgery in children: a large centre experience and review of the literature

BACKGROUND

Minimally invasive surgery (MIS) for hepatopancreatic and biliary (HPB) diseases has been widely used in adults, while in children, its application is limited due to its complexity. Herein, we report the experience of MIS for paediatric HPB diseases and literature review.

METHODS

All children (≤18 years-old) undergoing major HPB operations by MIS during January 2017-June 2020 in our institution were prospectively enrolled.

RESULTS

Out of 139 children operated on for HPB diseases with MIS, 26 (18.7%) patients (age: 11 (1-17) years-old; weight: 41.9 (10.7-75.5) kg) underwent major HPB surgery, including 11 pancreatic resections and 15 liver resections, all performed by a full-laparoscopic-technique. Four (15.3%) surgeries were electively converted to an open-technique for safer operative management. None required a blood transfusion. The median hospital admission was 6 days. Post-operatively, all patients had early mobilization and good recovery. Two (7.7%) patients experienced post-operative complications requiring radiological intervention. Oncological radical resection (R0) was achieved in all tumours, and after 2 years, all children were free of tumour recurrence.

CONCLUSION

MIS for HPB surgery is safe and feasible in children, with less surgical trauma, short hospital-stay and better aesthetic results. An adequate learning curve in specialized centres is essential for good outcomes.

[The use of long-acting somatostatin analogs in congenital hyperinsulinism]

BACKGROUND

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Pharmacological Correction of Trafficking Defects in ATP-sensitive Potassium Channels Caused by Sulfonylurea Receptor 1 Mutations

ATP-sensitive potassium (K_ATP) channels play a key role in mediating glucose-stimulated insulin secretion by coupling metabolic signals to β-cell membrane potential. Loss of K_ATP channel function due to mutations in ABCC8 or KCNJ11, genes encoding the sulfonylurea receptor 1 (SUR1) or the inwardly rectifying potassium channel Kir6.2, respectively, results in congenital hyperinsulinism. Many SUR1 mutations prevent trafficking of channel proteins from the endoplasmic reticulum to the cell surface. Channel inhibitors, including sulfonylureas and carbamazepine, have been shown to correct channel trafficking defects. In the present study, we identified 13 novel SUR1 mutations that cause channel trafficking defects, the majority of which are amenable to pharmacological rescue by glibenclamide and carbamazepine. By contrast, none of the mutant channels were rescued by K_ATP channel openers. Cross-linking experiments showed that K_ATP channel inhibitors promoted interactions between the N terminus of Kir6.2 and SUR1, whereas channel openers did not, suggesting the inhibitors enhance intersubunit interactions to overcome channel biogenesis and trafficking defects. Functional studies of rescued mutant channels indicate that most mutants rescued to the cell surface exhibited WT-like sensitivity to ATP, MgADP, and diazoxide. In intact cells, recovery of channel function upon trafficking rescue by reversible sulfonylureas or carbamazepine was facilitated by the K_ATP channel opener diazoxide. Our study expands the list of K_ATP channel trafficking mutations whose function can be recovered by pharmacological ligands and provides further insight into the structural mechanism by which channel inhibitors correct channel biogenesis and trafficking defects.

Novel ABCC8 (SUR1) gene mutations in Asian Indian children with congenital hyperinsulinemic hypoglycemia

Congenital hyperinsulinemic hypoglycemia (HI) is a heterogeneous genetic disorder of insulin secretion characterized by persistent hypoglycemia, most commonly associated with inactivating mutations of the β-cell ATP-sensitive K(+) channel (K(ATP) channel) genes ABCC8 (encoding SUR1) and KCNJ11(encoding Kir6.2). This study aimed to screen the mutations in the genes associated with congenital HI in Asian Indian children. Recessive mutations of these genes cause hyperinsulinism that is unresponsive to treatment with channel agonists like diazoxide. Dominant K(ATP) mutations have been associated with diazoxide-responsive disease. The KCNJ11, ABCC8, GCK, HNF4A, and GLUD1 genes were analyzed by sequence analysis in 22 children with congenital HI. We found 10 novel mutations (c.1delA, c.61delG, c.267delT, c.619-629delCCCGAGGACCT, Gln444*, Leu724Pro, Ala847Thr, Trp898*, IVS30-2A>C, and Leu1454Arg) and two known mutations (Gly111Arg and Arg598*) in the ABCC8 gene. This study describes novel and known ABCC8 gene mutations in children with congenital HI. This is the first large genetic screening study on HI in India and our results will help clinicians in providing optimal treatment for patients with hyperinsulinemia and in assisting affected families with genetic counseling.

An Egyptian case of congenital hyperinsulinism of infancy due to a novel mutation in KCNJ11 encoding Kir6.2 and response to octreotide

Congenital hyperinsulinism of infancy (CHI) is a rare heterogeneous disease mostly attributable to mutations in the genes encoding the KATP channel subunits found in pancreatic β-cells. Here, we report a child presenting at day 1 with persistent hyperinsulinemic hypoglycemia and who underwent open laparotomy and subtotal pancreatectomy with resection of tail and body of pancreas at 30 days of age. Normoglycemia was restored by Octreotide that was discontinued when the child was 7-month old. However, 3 months later Octreotide was re-administered as hypoglycemic attacks recurred. On follow-up, the child has adequate glycemic control and is thriving well with no neurodevelopmental morbidity. Genetic analysis revealed the novel mutation c.407G > A [p.R136H] in KCNJ11 encoding Kir6.2, confirming the diffuse form of CHI. This is to our knowledge the first reported Egyptian case of CHI due to a mutation in KCNJ11.

Laparoscopic distal pancreatectomy: Up-to-date and literature review

Pancreatic surgery represents one of the most challenging areas in digestive surgery. In recent years, an increasing number of laparoscopic pancreatic procedures have been performed and laparoscopic distal pancreatectomy (LDP) has gained world-wide acceptance because it does not require anastomosis or other reconstruction. To date, English literature reports more than 300 papers focusing on LDP, but only 6% included more than 30 patients. Literature review confirms that LDP is a feasible and safe procedure in patients with benign or low grade malignancies. Decreased blood loss and morbidity, early recovery and shorter hospital stay may be the main advantages. Several concerns still exist for laparoscopic pancreatic adenocarcinoma excision. The individual surgeon determines the technical conduction of LDP, with or without spleen preservation; currently robotic pancreatic surgery has gained diffusion. Additional researches are necessary to determine the best technique to improve the procedure results.

In vitro insulin secretion by pancreatic tissue from infants with diazoxide-resistant congenital hyperinsulinism deviates from model predictions

Congenital hyperinsulinism (CHI) is the major cause of persistent neonatal hypoglycemia. CHI most often occurs due to mutations in the ABCC8 (which encodes sulfonylurea receptor 1) or KCNJ11 (which encodes the potassium channel Kir6.2) gene, which result in a lack of functional KATP channels in pancreatic β cells. Diffuse forms of CHI (DiCHI), in which all β cells are abnormal, often require subtotal pancreatectomy, whereas focal forms (FoCHI), which are characterized by localized hyperplasia of abnormal β cells, can be cured by resection of the lesion. Here, we characterized the in vitro kinetics of insulin secretion by pancreatic fragments from 6 DiCHI patients and by focal lesion and normal adjacent pancreas from 18 FoCHI patients. Responses of normal pancreas were similar to those reported for islets from adult organ donors. Compared with normal pancreas, basal insulin secretion was elevated in both FoCHI and DiCHI tissue. Affected tissues were heterogeneous in their secretory responses, with increased glucose levels often producing a rapid increase in insulin secretion that could be followed by a paradoxical decrease below prestimulatory levels. The KATP channel blocker tolbutamide was consistently ineffective in stimulating insulin secretion; conversely, the KATP channel activator diazoxide often caused an unanticipated increase in insulin secretion. These observed alterations in secretory behavior were similar in focal lesion and DiCHI tissue, and independent of the specific mutation in ABCC8 or KCNJ11. They cannot be explained by classic models of β cell function. Our results provide insight into the excessive and sometimes paradoxical changes in insulin secretion observed in CHI patients with inactivating mutations of KATP channels.

Visualization of the focus in congenital hyperinsulinism by intraoperative sonography

In surgery for focal congenital hyperinsulinism (CHI), the identification and complete resection of the focus without collateral damage is of utmost importance. In a pilot study we applied intra-abdominal high-frequency sonography during surgery for focal CHI in 2 infants. The focus could be identified, its relation to the pancreatic and common bile duct could be shown, and the typical octopus-like tentacles could be demonstrated. In one case the resection was successful; in the other it was not. These preliminary results suggest that intraoperative sonography could be a valuable tool in the surgical therapy of focal CHI and warrants further evaluation in a clinical study.

Update of mutations in the genes encoding the pancreatic beta-cell K(ATP) channel subunits Kir6.2 (KCNJ11) and sulfonylurea receptor 1 (ABCC8) in diabetes mellitus and hyperinsulinism

The beta-cell ATP-sensitive potassium (K(ATP)) channel is a key component of stimulus-secretion coupling in the pancreatic beta-cell. The channel couples metabolism to membrane electrical events bringing about insulin secretion. Given the critical role of this channel in glucose homeostasis it is therefore not surprising that mutations in the genes encoding for the two essential subunits of the channel can result in both hypo- and hyperglycemia. The channel consists of four subunits of the inwardly rectifying potassium channel Kir6.2 and four subunits of the sulfonylurea receptor 1 (SUR1). It has been known for some time that loss of function mutations in KCNJ11, which encodes for Kir6.2, and ABCC8, which encodes for SUR1, can cause oversecretion of insulin and result in hyperinsulinism of infancy, while activating mutations in KCNJ11 and ABCC8 have recently been described that result in the opposite phenotype of diabetes. This review focuses on reported mutations in both genes, the spectrum of phenotypes, and the implications for treatment on diagnosing patients with mutations in these genes.

Advances in the diagnosis and management of hyperinsulinemic hypoglycemia

Hyperinsulinemic hypoglycemia (HH) is a consequence of unregulated insulin secretion by pancreatic beta-cells and is a major cause of hypoglycemic brain injury and mental retardation. Congenital HH is caused by mutations in genes involved in regulation of insulin secretion, seven of which have been identified (ABCC8, KCNJ11, GLUD1, CGK, HADH, SLC16A1 and HNF4A). Severe forms of congenital HH are caused by mutations in ABCC8 and KCNJ11, which encode the two components of the pancreatic beta-cell ATP-sensitive potassium channel. Mutations in HNF4A, GLUD1, CGK, and HADH lead to transient or persistent HH, whereas mutations in SLC16A1 cause exercise-induced HH. Rapid genetic analysis combined with an understanding of the histological features (focal or diffuse disease) of congenital HH and the introduction of (18)F-L-3,4-dihydroxyphenylalanine PET-CT to guide laparoscopic surgery have totally transformed the clinical approach to this complex disease. Adult-onset HH is mostly caused by an insulinoma; however, it has also been reported to present as postprandial HH in patients with noninsulinoma pancreatogenous hypoglycemia syndrome, in those who have undergone gastric-bypass surgery for morbid obesity, and in those with mutations in the insulin-receptor gene.

The laparoscopic approach toward hyperinsulinism in children

Hyperinsulinemic hypoglycemia (HH) in children requiring surgery is rare. Early HH can be the result of focal or diffuse pancreatic pathology. A number of genetic abnormalities in early HH have been identified, but in the majority of patients no abnormality is found. The sporadic focal and diffuse forms as well the autosomal recessive form are particularly therapy-resistant and demand for early surgery. Preoperative discrimination between focal and diffuse disease in early HH is difficult. 18 F DOPA PET in combination with CT is promising as is laparoscopic exploration of the pancreas. Frozen section biopsy analysis has not been uniformly beneficial. If macroscopically no focal lesion is found, limited laparoscopic distal pancreatectomy provides tissue for definitive pathologic examination. Subsequent near total laparoscopic spleen-saving pancreatectomy surgery is not particularly difficult. Later HH may occur in the context of the MEN-1 syndrome and is then multifocal in nature. In MEN-1 patients, a distal spleen-saving pancreatectomy with enucleation of lesions in the head seems justified. Insulin-producing lesions in non-MEN-1 patients should be enucleated. There should always be a suspicion of malignancy. Also, in older children, surgery for hyperinsulinism should be performed laparoscopically.

Laparoscopic pancreatic resection: the past, present, and future

Since the early 1990s, laparoscopic techniques have been applied to a growing number of pancreatic surgeries. Laparoscopic pancreatic resections have been performed in patients with a variety of diseases including chronic pancreatitis, pancreatic trauma, congenital hyperinsulinism, and neoplasms of the pancreas; e.g., insulinoma, mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, etc. Laparoscopic pancreatic resections with an en bloc lymph node dissection have also been performed for invasive carcinomas. The long-term results after laparoscopic resections for invasive pancreatic cancer, however, are still not well defined. Laparoscopic distal pancreatectomies with or without spleen preservation may benefit patients with reduced postoperative pain, shorter hospital stay, a quicker recovery to normal activity, and better cosmetic appearances based on retrospective analyses of collective series and case reports. Prospective randomized controlled trials are needed to validate these benefits. In contrast, laparoscopic proximal pancreatectomies with or without duodenum preservation remain controversial. Although a laparoscopic pancreaticoduodenectomy and laparoscopic duodenum-preserving pancreatic head resection are technically feasible, laparoscopic reconstruction after proximal pancreatectomies is not yet generally practicable but limited to personal experiences by highly skilled endoscopic surgeons. To justify the performance of laparoscopic proximal pancreatectomies, it is mandatory to demonstrate the potential clinical benefits and safety of these complicated procedures.

Mechanisms of Disease: advances in diagnosis and treatment of hyperinsulinism in neonates

Hyperinsulinism is the single most common mechanism of hypoglycemia in neonates. Dysregulated insulin secretion is responsible for the transient and prolonged forms of neonatal hypoglycemia, and congenital genetic disorders of insulin regulation represent the most common of the permanent disorders of hypoglycemia. Mutations in at least five genes have been associated with congenital hyperinsulinism: they encode glucokinase, glutamate dehydrogenase, the mitochondrial enzyme short-chain 3-hydroxyacyl-CoA dehydrogenase, and the two components (sulfonylurea receptor 1 and potassium inward rectifying channel, subfamily J, member 11) of the ATP-sensitive potassium channels (K(ATP) channels). K(ATP) hyperinsulinism is the most common and severe form of congenital hyperinsulinism. Infants suffering from K(ATP) hyperinsulinism present shortly after birth with severe and persistent hypoglycemia, and the majority are unresponsive to medical therapy, thus requiring pancreatectomy. In up to 40-60% of the children with K(ATP) hyperinsulinism, the defect is limited to a focal lesion in the pancreas. In these children, local resection results in cure with avoidance of the complications inherent to a near-total pancreatectomy. Hyperinsulinism can also be part of other disorders such as Beckwith-Wiedemann syndrome and congenital disorders of glycosylation. The diagnosis and management of children with congenital hyperinsulinism requires a multidisciplinary approach to achieve the goal of therapy: prevention of permanent brain damage due to recurrent hypoglycemia.

Contemporary strategies in the diagnosis and management of neonatal hyperinsulinaemic hypoglycaemia

Congenital hyperinsulinism (CHI) is a genetically and phenotypically diverse syndrome. Key management issues involve early diagnosis by ensuring that appropriate samples are taken at the point of hypoglycaemia, prevention of recurrent hypoglycaemia, and detailed characterisation of the clinical, biochemical, and genetic features of each case. Infants with persistent diazoxide resistant CHI require evaluation at specialist referral centres equipped to differentiate those with focal (fo-HI) and diffuse (di-HI) pancreatic disease. Fo-HI is treated with selective pancreatic resection but di-HI is treated by surgery only if intensive medical management regimes are not efficacious.