Congenital hyperinsulinism in two siblings with ABCC8 mutation: same genotype, different phenotypes

SUMMARY Congenital hyperinsulinism (CHI) is a heterogenous disease caused by insulin secretion regulatory defects, being ABCC8/KCNJ11 the most commonly affected genes. Therapeutic options include diazoxide, somatostatin analogues and surgery, which is curative in focal CHI. We report the case of two siblings (born two years apart) that presented themselves with hypoketotic hyperinsulinemic persistent hypoglycemias during neonatal period. The diagnosis of diffuse CHI due to an ABCC8 compound mutation (c.3576delG and c.742C>T) was concluded. They did not benefit from diazoxide therapy (or pancreatectomy performed in patient number 1) yet responded to somatostatin analogues. Patient number 1 developed various neurological deficits (including epilepsy), however patient number 2 experienced an entirely normal neurodevelopment. We believe this case shows how previous knowledge of the firstborn sibling's disease contributed to a better and timelier medical care in patient number 2, which could potentially explain her better neurological outcome despite their same genotype.

A Portulaca oleracea L. extract promotes insulin secretion via a K⁺(ATP) channel dependent pathway in INS-1 pancreatic β-cells

BACKGROUND/OBJECTIVE: This study was designed to investigate how a Portulaca oleracea L. extract (POE) stimulates insulin secretion in INS-1 pancreatic β-cells. MATERIALS/METHOD: INS-1 pancreatic β-cells were incubated in the presence of various glucose concentrations: 1.1 or 5.6, 16.7 mM glucose. The cells were treated with insulin secretagogues or insulin secretion inhibitor for insulin secretion assay using an insulin ELISA kit. In order to quantify intracellular influx of Ca2+ caused by POE treatment, the effect of POE on intracellular Ca2+ in INS-1 pancreatic β-cells was examined using Fluo-2 AM dye. RESULTS: POE at 10 to 200 µg/mL significantly increased insulin secretion dose-dependently as compared to the control. Experiments at three glucose concentrations (1.1, 5.6, and 16.7 mM) confirmed that POE significantly stimulated insulin secretion on its own as well as in a glucose-dependent manner. POE also exerted synergistic effects on insulin secretion with secretagogues, such as L-alanine, 3-isobutyl-1-methylxanthine, and especially tolbutamide, and at a depolarizing concentration of KCl. The insulin secretion caused by POE was significantly attenuated by treatment with diazoxide, an opener of the K+ ATP channel (blocking insulin secretion) and by verapamil (a Ca2+ channel blocker). The insulinotropic effect of POE was not observed under Ca2+-free conditions in INS-1 pancreatic β-cells. When the cells were preincubated with a Ca2+ fluorescent dye, Fluo-2 (acetoxymethyl ester), the cells treated with POE showed changes in fluorescence in red, green, and blue tones, indicating a significant increase in intracellular Ca2+, which closely correlated with increases in the levels of insulin secretion. CONCLUSIONS: These findings indicate that POE stimulates insulin secretion via a K+ ATP channel-dependent pathway in INS-1 pancreatic β-cells.

Effects of diazoxide in experimental acute necrotizing pancreatitis

OBJECTIVE: We aimed to assess the effects of diazoxide on the mortality, pancreatic injury, and inflammatory response in an experimental model of acute pancreatitis. METHODS: Male Wistar rats (200-400 g) were divided randomly into two groups. Fifteen minutes before surgery, animals received physiological (0.9%) saline (3 mL/kg) (control group) or 45 mg/kg diazoxide (treatment group) via the intravenous route. Acute pancreatitis was induced by injection of 2.5% sodium taurocholate via the biliopancreatic duct. Mortality (n=38) was observed for 72 h and analyzed by the Mantel-Cox Log-rank test. To study pancreatic lesions and systemic inflammation, rats (10 from each group) were killed 3 h after acute pancreatitis induction; ascites volume was measured and blood as well as pancreases were collected. Pancreatic injury was assessed according to Schmidt's scale. Cytokine expression in plasma was evaluated by the multiplex method. RESULTS: Mortality at 72 h was 33% in the control group and 60% in the treatment group (p=0.07). Ascites volumes and plasma levels of cytokines between groups were similar. No difference was observed in edema or infiltration of inflammatory cells in pancreatic tissues from either group. However, necrosis of acinar cells was lower in the treatment group compared to the control group (3.5 vs. 3.75, p=0.015). CONCLUSIONS: Treatment with diazoxide can reduce necrosis of acinar cells in an experimental model of acute pancreatitis, but does not affect the inflammatory response or mortality after 72 h.

Congenital hyperinsulinism: diagnostic and management challenges in a developing country – case report

Management of congenital hyperinsulinemia of infancy (CHI) is challenging. A 4-month-old female infant with persistent hypoglycemia and elevated insulin levels was diagnosed with CHI. Gallium-68 DOTANOC positron emission tomography/computed tomography (PET/CT) scan (⁶⁸Ga-labeled [1,4,7,10-tetraazacyclododecane-N,N’,N’’,N’’’-tetraacetic acid]-1-NaI3-octreotide) demonstrated focal disease in the body of the pancreas. Genetic studies indicated paternal inheritance, making focal disease likely. She was started on diazoxide therapy with partial improvement in blood glucose levels. Due to a suboptimal response to diazoxide and the likelihood of focal disease amenable to surgery, a laparoscopic subtotal pancreatectomy with preservation of the head of the pancreas was performed. The biopsy demonstrated diffuse hyperplastic pancreatic islet cells on immunohistochemistry, indicative of diffuse rather than focal disease. Paternal inheritance is a recognized indicator of focal disease. Gallium-68 DOTANOC PET/CT scan is the only available imaging modality in South India as ¹⁸F-L-dihydroxyphenylalanine (DOPA) PET/CT scan is not available at present. A laparoscopic approach reduces the postoperative recovery time and morbidity in such patients. The absence of ¹⁸F-L-DOPA PET/CT scan and the limited supply of diazoxide makes the management of this complex condition more challenging in developing countries.

A case report on congenital hyperinsulinism associated with ABCC8 nonsense mutation: Good response to octreotide / Journal of the ASEAN Federation of Endocrine Societies

@#<p style="text-align: justify;">A 2.4 kg baby boy born via Caesarian section at 35 weeks had the first onset of hypoglycemia at 2 hours of life. The infant required a glucose load of 30 mg/kg/min. Insulin level was 19.6 pmol/L (normal value 17.8-173.0) in the absence of ketosis. He was resistant to oral diazoxide but responded to octreotide infusion. The boy was found to be heterozygous for an ABCC8 nonsense mutation, p.R934*. We present our experience on the use of subcutaneous octreotide for 2 years for the treatment of diazoxide resistant congenital hyperinsulinism (CHI).</p>

Energy intake underreporting of adults in a household survey: the impact of using a population specific basal metabolic rate equation / Subestimativa da ingestão energética em amostra probabilística de adultos: o impacto do uso de equações específicas para taxa metabólica basal / Subestimación de la ingesta energética en una muestra probabilística de adultos: el impacto del uso de ecuaciones específicas para la tasa metabólica basal

The purpose of the present study was to identify energy intake (EI) underreporting and to estimate the impact of using a population specific equation for the basal metabolic rate (BMR) in a probability sample of adults from Niterói, Rio de Janeiro State, Brazil. A sample of 1,726 subjects participated in the study. EI was assessed by a 24-hour dietary recall and EI/BMR was computed with BMR estimated using internationally recommended equations as well as specific equations developed for the adult population of Niterói. Mean EI was 1,570.9 and 2,188.8kcal.day-1 for women and men, respectively. EI decreased with increasing age in both men and women. BMR estimated by the Brazilian equation was significantly lower than the values estimated by the international equation for all age, sex and nutritional status groups. In general, EI underreporting was found in at least 50% of the population, higher in women, and increased with increasing age and body mass index (BMI). The results of the present study confirm that EI is underreported, even when BMR is estimated using population-specific equations.

O objetivo do presente estudo foi identificar a subestimativa da ingestão energética (IE) e estimar o impacto do uso de uma equação específica da população para a taxa metabólica basal (TMB), em amostra probabilística de adultos do Município de Niterói, Rio de Janeiro, Brasil. Uma amostra de 1.726 indivíduos da população adulta participou do estudo. Ingestão energética foi avaliada por um recordatório de 24 horas e IE/TMB foi calculada com TMB estimada pelas equações recomendadas e pelas equações específicas para a população. A média da IE foi 1.570,9 e 2.188,8kcal.dia-1 em mulheres e homens, respectivamente. A ingestão energética diminuiu com o aumento da idade em homens e mulheres. A taxa metabólica basal estimada pela equação brasileira foi significativamente menor do que os valores estimados pela equação recomendada para todas as idades, sexo e estado nutricional. Em geral, a subestimativa da IE foi encontrada em pelo menos 50% da população, maior em mulheres, e aumentou com o avanço da idade e índice de massa corporal (IMC). Os resultados confirmam que IE é subestimada, mesmo quando a TMB é estimada pelas equações da população específica.

El objetivo del presente estudio fue identificar la subestimación de la ingesta energética (IE) y estimar el impacto del uso de una ecuación específica de la población para la tasa metabólica basal (TMB), en una muestra probabilística de adultos del municipio de Niterói, Río de Janeiro, Brasil. Una muestra de 1.726 individuos de la población adulta participó en el estudio. La ingesta energética fue evaluada mediante un recordatorio de 24 horas y las IE/TMB fueron calculadas con una TMB estimada por las ecuaciones recomendadas y por las ecuaciones específicas para la población. La media de la IE fue 1.570,9 y 2.188,8kcal.día-1 en mujeres y hombres, respectivamente. La ingesta energética disminuyó con el aumento de la edad en hombres y mujeres. La tasa metabólica basal estimada por la ecuación brasileña fue significativamente menor que los valores estimados por la ecuación recomendada para todas las edades, sexo y estado nutricional. En general, la subestimación de la IE se encontró en por lo menos un 50% de la población, fue mayor en mujeres y aumentó con el aumento de la edad e índice de masa corporal (IMC). Los resultados confirman que la IE está subestimada, incluso cuando la TMB está estimada por las ecuaciones de población específica.

Efeito do diazóxido nas lesões da isquemia/reperfusão hepática: estudo experimental em ratos / Effect of diazoxide in the lesions of ischemia/ reperfusion liver: experimental study in rats

INTRODUÇÃO: A lesão de isquemia/reperfusão hepática ocorre durante cirurgias hepáticas de grande porte, transplante de fígado e no trauma abdominal. A lesão de isquemia/reperfusão hepática ocasiona lesões no fígado e pode desencadear uma síndrome inflamatória sistêmica com lesões de órgãos a distância. Estudos anteriores demonstraram que o diazóxido protege outros órgãos (coração, rins, cérebro) da lesão de isquemia/reperfusão destes órgãos. OBJETIVO: Investigar o efeito da administração do diazóxido na lesão de isquemia/reperfusão hepática. MÉTODOS: Ratos Wistar machos foram divididos em 3 grupos. Em 2 grupos, os animais foram submetidos à isquemia hepática parcial realizada por clampeamento do pedículo dos lobos mediano e lateral anterior esquerdo durante uma hora sob ventilação mecânica. Grupo Salina (n=26): ratos receberam solução salina e Grupo Diazóxido (n=26): ratos receberam diazóxido EV ( 3.5mg/kg ) 15 minutos antes da reperfusão hepática. No terceiro grupo, Grupo Controle (n = 22 ), os ratos foram submetidos apenas à anestesia e manipulação cirúrgica. Quatro e 24 horas após os procedimentos, amostras de sangue foram recolhidas para determinações de AST, ALT, TNF-alfa, IL-6, IL-10, de nitrito/nitrato, creatinina. Amostras teciduais do fígado foram analisadas para dosagem do malondialdeído (MDA), para o estudo das funções oxidativas e fosforilativas mitocondriais, e para a análise histológica. Pela coleta de tecido pulomonar, a permeabilidade vascular pulmonar e a atividade da mieloperoxidade (MPO) também foram determinados. RESULTADOS: Quatro horas após, a reperfusão o Grupo Diazóxido apresentou elevações de AST, ALT, TNF-alfa, IL-6, IL-10 e níveis séricos de nitrito/nitrato significativamente menores que o Grupo Controle (p < 0,05). Observou-se uma redução significativa da disfunção mitocondrial hepática no Grupo Diazóxido em comparação com o Grupo Controle (p < 0,05). Não foram observadas diferenças no conteúdo de MDA fígado, na creatinina sérica e...

INTRODUCTION: Significant liver ischemia/reperfusion injury can occur during hepatic surgeries, liver transplantation and abdominal trauma. Hepatic ischemia/reperfusion can trigger a local and systemic inflammatory syndrome. Previous studies have shown that diazoxide protects other organs (heart, kidneys, brain) from ischemia/reperfusion injury. AIM: To investigate the effect of diazoxide administration on liver ischemic/reperfusion injury. METHODS: Wistar male rats were divided into 3 groups. In two groups the rats underwent partial liver ischemia performed by clamping the pedicle from medium and left anterior lateral segments during an hour under mechanical ventilation. Saline Group (n=26): rats received saline and Diazoxide Group (n=26): rats received IV diazoxide (3.5mg/kg) 15 minutes before liver reperfusion. The third group, the Control Group (n=22) the rats underwent only anesthesia and surgical manipulation. Four and 24 hours after the procedure blood were collected for determinations of AST, ALT, TNF-alfa, IL-6, IL-10, nitrite/nitrate, creatinine. Liver tissues were assembled for mitochondrial oxidation and phosphorylation, malondialdehyde (MDA) content, and histologic analysis. Pulmonary vascular permeability and myeloperoxidade (MPO) were also determined. RESULTS: Four hours after reperfusion Diazoxide Group presented elevation of AST, ALT, TNF-alfa, IL-6, IL-10 and nitrite/nitrate serum levels significantly lower than Control Group (p < 0.05). A significant reduction on liver mitochondrial dysfunction were observed in Diazoxide Group compared to Control Group (p < 0.05). No differences in liver MDA content,serum creatinine and in pulmonary vascular permeability and MPO activity were observed between groups. Twenty four hours after reperfusion Diazoxide Group showed a reduction of AST, ALT and TGF?1 serum levels when compared to Control group (p < 0.05). CONCLUSION: Diazoxide maintains liver mitochondrial function, increases liver...

A Case of 2-Month-Old Infant with Persistent Hyperinsulinemic Hypoglycemia Presenting as Atonic Seizure

Congenital hyperinsulinism is the most frequent cause of severe, persistent hypoglycemia in infancy and childhood. It is caused by an inappropriate insulin secretion from the pancreatic beta-cells secondary to various genetic disorders. Recognition of this entity becomes important due to the fact that hypoglycemia is very severe and frequent and that it may lead to severe neurological damage in the infant manifesting as mental or psychomotor retardation or even a life-threatening events if not recognized and treated effectively in time. Hypoglycemias can be detected by seizures, fainting, or any other neurological symptoms in the neonatal period or later, usually within the first two years of life. Hypoglycemias must be rapidly and intensively treated to prevent severe and irreversible brain damages. Next, a treatment to prevent the recurrence of hypoglycemia must be set, which may include frequent and glucose-enriched feeding, diazoxide and octreotide. We report a case of congenital hyperinsulinemia in a 2 months old infant presenting as atonic seizure which has been treated with diazoxide.

Congenital hyperinsulinism: current status and future perspectives

The diagnosis and treatment of congenital hyperinsulinism (CHI) have made a remarkable progress over the past 20 years and, currently, it is relatively rare to see patients who are left with severe psychomotor delay. The improvement was made possible by the recent developments in the understanding of the molecular and pathological basis of CHI. Known etiologies include inactivating mutations of the K(ATP) channel genes (ABCC8 and KCNJ11) and HNF4A, HNF1A, HADH, and UCP2 or activating mutations of GLUD1, GCK, and SLC16A1. The understanding of the focal form of K(ATP) channel CHI and its detection by 18F-fluoro-L-DOPA positron emission tomography have revolutionized the management of CHI, and many patients can be cured without postoperative diabetes mellitus. The incidence of the focal form appears to be higher in Asian countries; therefore, the establishment of treatment systems is even more important in this population. In addition to diazoxide or long-term subcutaneous infusion of octreotide or glucagon, long-acting octreotide or lanreotide have also been used successfully until spontaneous remission. Because of these medications, near-total pancreatectomy is less often performed even for the diazoxide-unresponsive diffuse form of CHI. Other promising medications include pasireotide, small-molecule correctors such as sulfonylurea or carbamazepine, GLP1 receptor antagonists, or mammalian target of rapamycin inhibitors. Unsolved questions in this field include the identification of the remaining genes responsible for CHI, the mechanisms leading to transient CHI, and the mechanisms responsible for the spontaneous remission of CHI. This article reviews recent developments and hypothesis regarding these questions.

Mitochondrial Channel Opener Diazoxide Attenuates Hypoxia-Induced sFlt-1 Release in Human Choriocarcinoma Cells

OBJECTIVES: To examine the effect of diazoxide on hypoxia-induced soluble fms-like tyrosin kinase-1 (sFlt-1) release in JEG-3 choriocarcinoma cells. METHODS: Cells were cultured under normoxia (20% O2) or hypoxia (1% O2), and expression of sFlt-1 mRNA and protein release was determined by quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) assays and enzyme-linked immunosorbent assay (ELISA). RESULTS: Tumor necrosis factor-alpha (TNF-alpha) as well as hypoxia stimulated sFlt-1 release and diazoxide inhibited both of them. The selective inhibitor of mitochondrial adenosine triphosphat (ATP)-sensitive K+ channel opener (K(ATP)) 5-hydroxydecanoate (5-HD) completely reversed the diazoxide-induced inhibition of hypoxia-stimulated sFlt-1 release. qRT-PCR and Western blot analyses showed that diazoxide up-regulated the heme oxygenase-1 (HO-1) expression. In addition, the HO-1 inducer cobalt protoporphyrin (CoPP) and the metabolic product of HO-1 bilirubin mimicked diazoxide to inhibit sFlt-1 release and reactive oxygen species (ROS) production under hypoxia, whereas the HO-1 inhibitor zinc protoporphyrin IX (ZnPP IX) antagonized the effect of diazoxide. In cells transfected with the HO-1 siRNA, diazoxide did not exert any effect on sFlt-1 release and ROS production under hypoxia. CONCLUSION: These results, taken together, strongly suggest that up-regulation of the HO-1 expression is the crucial mechanism responsible for the diazoxide-induced inhibition of the sFlt-1 release and ROS production under hypoxia.

The hydrogen sulfide donor, Lawesson's reagent, prevents alendronate-induced gastric damage in rats

Our objective was to investigate the protective effect of Lawesson's reagent, an H2S donor, against alendronate (ALD)-induced gastric damage in rats. Rats were pretreated with saline or Lawesson's reagent (3, 9, or 27 µmol/kg, po) once daily for 4 days. After 30 min, gastric damage was induced by ALD (30 mg/kg) administration by gavage. On the last day of treatment, the animals were killed 4 h after ALD administration. Gastric lesions were measured using a computer planimetry program, and gastric corpus pieces were assayed for malondialdehyde (MDA), glutathione (GSH), proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-1β], and myeloperoxidase (MPO). Other groups were pretreated with glibenclamide (5 mg/kg, ip) or with glibenclamide (5 mg/kg, ip)+diazoxide (3 mg/kg, ip). After 1 h, 27 µmol/kg Lawesson's reagent was administered. After 30 min, 30 mg/kg ALD was administered. ALD caused gastric damage (63.35±9.8 mm2); increased levels of TNF-α, IL-1β, and MDA (2311±302.3 pg/mL, 901.9±106.2 pg/mL, 121.1±4.3 nmol/g, respectively); increased MPO activity (26.1±3.8 U/mg); and reduced GSH levels (180.3±21.9 µg/g). ALD also increased cystathionine-γ-lyase immunoreactivity in the gastric mucosa. Pretreatment with Lawesson's reagent (27 µmol/kg) attenuated ALD-mediated gastric damage (15.77±5.3 mm2); reduced TNF-α, IL-1β, and MDA formation (1502±150.2 pg/mL, 632.3±43.4 pg/mL, 78.4±7.6 nmol/g, respectively); lowered MPO activity (11.7±2.8 U/mg); and increased the level of GSH in the gastric tissue (397.9±40.2 µg/g). Glibenclamide alone reversed the gastric protective effect of Lawesson's reagent. However, glibenclamide plus diazoxide did not alter the effects of Lawesson's reagent. Our results suggest that Lawesson's reagent plays a protective role against ALD-induced gastric damage through mechanisms that depend at least in part on activation of ATP-sensitive potassium (KATP) channels.

Protective effects of mitochondrial ATP-sensitive potassium channel on A549 cell apoptosis induced by hyperoxia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To explore the protective effects of mitochondrial ATP-sensitive potassium channel opener diazoxide on hyperoxia-induced apoptosis of type II alveolar epithelial cells (A549 cells) and possible mechanisms.</p><p><b>METHODS</b>A549 cells were cultured in vitro and divided randomly into control, hyperoxia and diazoxide group. The hyperoxia group was exposed to a mixture of O2 (900 mL/L) and CO2 (50 mL/L) for 10 minutes, then cultured in a closed environment. The diazoxide group was pretreated with diazoxide of 100 μmol/L for 24 hrs before hyperxia induction. The cells were collected 12, 24 and 48 hrs after culture. The morphologic changes of A549 cells were observed under an inverted microscope. A549 cell apoptosis was detected by flow cytometry. The expression of Omi/HtrA2 in the endochylema of A549 cells was determined by immunohistochemistry.</p><p><b>RESULTS</b>A549 cells were damaged and the changes in morphology of the cells were serious in the hyperoxia group. The apoptosis rate of A549 cells and the expression of Omi/HtrA2 in the endochylema increased in the hyperoxia group compared with the control group (P<0.05). The growth and the morphology of A549 cells were greatly improved and the cell injuries were obviously alleviated in the diazoxide group. The expression of Omi/HtrA2 in the endochylema and the apoptosis rate of A549 cells were significantly reduced in the diazoxide group compared with the hyperoxia group (P<0.05).</p><p><b>CONCLUSIONS</b>Diazoxide as an opener of mitoKATP channel can reduce the expression of Omi/HtrA2 and the apoptosis rate of A549 cells, thus relieves the injury of A549 cells induced by hyperoxia.</p>

Potassium channel openers exhibit cross-tolerance with morphine in two experimental models of pain / Los abridores de canales de potasio exhiben tolerancia cruzada con la morfina en dos modelos experimentales de dolor

OBJECTIVE: The study was performed to assess the effect of potassium channel openers on morphine tolerance and vice-versa. METHODS: Swiss albino mice of either gender weighing between 25-30 g were used for the study. The study assesses the effect of potassium channel openers (cromakalim, diazoxide and minoxidil) on morphine tolerance and vice-versa, using formalin and tail-flick tests. RESULTS: The antinociceptive effect of cromakalim and minoxidil was significantly reduced when administered to morphine-tolerant mice, in both the behavioural tests. However, reduced analgesic effect of diazoxide was observed on morphine-tolerance in the formalin test but not in the tail-flick test. Tolerance was observed when morphine was administered to animals chronically treated with any of the potassium channel openers. The same effect was observed when morphine was injected into a group treated with a combination of morphine and any of the potassium channel openers. CONCLUSIONS: This study, therefore, suggests that both morphine and potassium channel openers are cross-tolerant. However, such interaction occurs at the level of potassium channels rather than at the level of receptors.

OBJETIVO: El estudio fue realizado para evaluar el efecto de los abridores de canales de potasio en la tolerancia a la morfina, y viceversa. MÉTODOS: Para el estudio, se usaron ratones albinos suizos de ambos sexos que pesaban entre 25-30 g. El estudio evalúa el efecto de los abridores de canales de potasio (cromacalina, diazóxido y minoxidil) en la tolerancia a la morfina, y viceversa, usando la prueba de la sacudida de la cola y la prueba de la formalina. RESULTADOS: El efecto antinociceptivo de la cromacalina y el minoxidil fue significativamente reducido cuando se le administró a los ratones tolerantes a la morfina, en ambas pruebas conductuales. Sin embargo, se observó un efecto analgésico reducido de diazóxido sobre la tolerancia a la morfina en la prueba de la formalina, pero no en la prueba de la sacudida de la cola. Se observó tolerancia al administrar morfina a animales crónicamente tratados con cualquiera de los abridores de canales de potasio. El mismo efecto fue observado cuando se inyectó la morfina al grupo tratado con una combinación de morfina y cualquiera de los abridores de canales de potasio. CONCLUSIONES: Por consiguiente, este estudio sugiere que tanto la morfina como los abridores de canales de potasio son tolerantes cruzados. Sin embargo, tal interacción ocurre a nivel de los canales de potasio más bien que a nivel de los receptores.

Persistent hyperinsulinemic hypoglycemia of infancy due to homozygous KCNJ11 (T294M) mutation.

Hyperinsulinemic hypoglycemia is the most common cause of persistent hypoglycemia in infancy. While most of the cases are sporadic more than 100 mutations have been reported in the familial type. The authors report a case of familial hyperinsulinemic hypoglycemia with homozygous T294M mutation of the KCNJ11 gene, which responded to diazoxide therapy.

Effects of diazoxide on the mitochondrial ultrastructure and permeability in donor rat myocardium / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effect of diazoxide (DE) on the myocardial ultrastructure and opening of maitochondrial permeability transition pore (MPTP) in donor rat heart suffered from long-term hypothermic preservation.</p><p><b>METHODS</b>The Langendorff model of isolated rat heart was used. The hearts were stored in 4 degrees C Celsior solution containing different concentration of DE (15, 30, or 45 micromol/L) for 9 h followed by 60 min of reperfusion. The recovery of rate-pressure product (RPP) was observed. The opening of MPTP and myocardial mitochondria ultrastructure were also evaluated.</p><p><b>RESULTS</b>(1) As compared with the celsior solution preserved group, DE (30 micromol/L) increased recovery of RPP during reperfusion and inhibited the opening of MPTP. DE also alleviated the myocardial mitochondrial ultrastucture damage induced by long-term hypothermic preservation. (2) The above effects of DE were attenuated by a mitoK(ATP) channel inhibitor 5-hydroxydecanoate and a MPTP opener atractyloside.</p><p><b>CONCLUSION</b>In the donor rat heart, DE protects myocardial mitochondria ultrastructure against long-term hypothermic preservation injury via inhibiting the opening of MPIP.</p>

Effect of K-ATP channel opener diazoxide on islet cell apoptosis and the expressions of apoptosis-related genes / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of potassium channel opener (diazoxide) on the islet cells apoptosis and bcl-2 and bax gene expressions in diabetic rats.</p><p><b>METHODS</b>Islet cell apoptosis was induced by intraperitoneal injection of streptozocin (STZ). The rats were randomly allocated into normal control group (NC group), diabetes mellitus group (DM group), and diazoxide group (DIA group), all treated with diazoxide for 4 weeks. During and after the treatment, the general state, body weight, fasting plasma glucose (FPG), food intake, and oral glucose tolerance of the rats were assessed. The expressions of Bcl-2 and Bax in rat islet cells were measured by immunohistochemistry, and the cell apoptosis was analyzed by TUNEL assay.</p><p><b>RESULTS</b>Compared with the NC group, the rats in the DM group showed significantly decreased body weight (P<0.05), increased blood glucose at o and 120 min after oral glucose administration, decreased expressions of Bcl-2 (P<0.01), increased expression of Bax (P<0.01), and increased islet cell apoptosis (P<0.05). Diazoxide treatment significantly decreased the body weight (P<0.05), decreased the blood glucose, increased Bcl-2 expression (P<0.01), decreased Bax expression (P<0.05), and reduced the islet cell apoptosis (P>0.05) of the diabetic rats.</p><p><b>CONCLUSION</b>By causing potassium channel opening, diazoxide can obviously improve the oral glucose tolerance, reduce the body weight, and up-regulate Bcl-2 and down-regulate Bax expression in diabetic rats. Diazoxide can also reduce the apoptosis of the islet cells in diabetic rats.</p>

Effect of diazoxide on oxygen free radicals and cell apoptosis in brain tissue after deep hypothermia cerebral ischemia reperfusion injury in young rats / 中华外科杂志

<p><b>OBJECTIVE</b>To determine the effects of diazoxide on oxygen free radicals and cell apoptosis in brain tissue after deep hypothermia cerebral ischemia reperfusion injury in young rats.</p><p><b>METHODS</b>Fifty-four 3-week-old Sprague-Dawley rats were randomly and equitably divided into sham-operated group, model group and diazoxide group respectively (n = 18). The model of hypothermia cerebral ischemia reperfusion injury was made. After 24 hours of operation, the brains of rats were removed and preserved. The content of superoxide dismutase (SOD) and malonaldehyde (MDA) in brain tissue were detected. Cytosolic C release of cytochrome was confirmed by Western Blot. The protein expression of Caspase-3 was determined by immunohistochemistry.</p><p><b>RESULTS</b>In the model group, the content of SOD was (198 +/- 41) U/mg, lower than the sham-operated group's (321 +/- 36) U/mg (P < 0.01). The content of MDA was (212 +/- 21) nmol/mg, was higher than the sham-operated group's (100 +/- 23) nmol/mg (P < 0.01), and the expressions of cytochrome C (0.72 +/- 0.09) and Caspase-3 (83 +/- 10) were all significantly higher than those in the sham-operated group (0.17 +/- 0.02 and 115 +/- 9) (P < 0.01). Compared with the model group, the content of SOD in the diazoxide group [(264 +/- 34) U/mg] was markedly increased (P < 0.05). In addition, diazoxide provided significant reductions in the content of MDA [(174 +/- 19) nmol/mg] and the expressions of cytochrome C (0.41 +/- 0.05) and Caspase-3 (99 +/- 11) (P < 0.05).</p><p><b>CONCLUSIONS</b>The neuroprotective effects of diazoxide against brain injury induced by deep hypothermia cerebral ischemia reperfusion through inhibiting oxygen free radicals and cell apoptosis. Diazoxide may become a new neuroprotective drug after infant complicated congenital cardiac operation.</p>

Hepatectomía izquierda por metástasis insulino-secretantes, a los 15 años de la resección de un insulinoma / Left hepatectomy associated with liver metastases, 15 years after resection of a pancreatic insulinoma

La insulinoma se origina en las células de los islotes pancreáticos. Es un tumor poco común que ocurre en aproximadamente 1 a 6 personas por millones de habitantes por año. Predomina en el sexo femenino, entre los 40 y 60 años de edad. Se estima que aproximadamente entre el 6 al 10% son neoplasias malignas. El objetivo del trabajo es la presentación de un paciente con recurrencia del cuadro clínico (hipoglucemia, hiperinsulinismo) asociado a metástasis hepáticas 15 años después de la resección de un insulinoma pancreático...

Insulinoma is a neoplasm that arises from the pancreatic insulin-producing cells. It is a rare tumor that occurs in approximately 1 to 6 persons per million of population per year. Predominates in females, between 40 and 60 years of age. It is estimated that approximately 6 to 10% are malignant. Objective: the presentation of a patient with recurrence of clinical symptoms (hypoglycemia, hyperinsulinism) associated with liver metastases 15 years after resection of a pancretic insulinoma..

Diabetes counteracts the protective effect of the diazoxide preconditioning on ischemic reperfused rat heart / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the impact of diabetic condition on the protective effect of diazoxide preconditioning (DPC) on ischemic-reperfused (I/R) myocardium in rats.</p><p><b>METHODS</b>Thirty normal male Sprague-Dawley rats were divided into 3 groups, including non-diabetic control group, non-diabetic I/R group, and non-diabetic I/R DPC group. Thirty diabetic male rats were also divided into the same 3 groups. The Langendorff isolated heart perfusion models were established. The control groups had a 90 min perfusion without any intervention. The I/R groups had a 30 min equilibration period, a 30 min ischemia, and a 30 min reperfusion. The I/R DPC groups had a 10 min equilibration, two cycles of 100 micromol/L diazoxide perfusion, 5 min each, followed by a 5 min diazoxide-free period before the 30 min ischemia and a 30 min reperfusion. The recovery rate of the left ventricular function, including cardiac output, left ventricular developed pressure (LVDP), and the maximum change rate of left ventricular pressure rise and fall (+/- dp/dt(max)) were recorded. The activity of creatine kinase in coronary outflow and activities of malonyldialdehyde, and superoxide dismutase in myocardium were detected. Myocardial water content was also assessed.</p><p><b>RESULTS</b>In non-diabetic rats, the content of creatine kinase, malonyldialdehyde and water content were significantly decreased in I/R DPC group compared with those in I/R group. Furthermore, in I/R DPC group, the activity of superoxide dismutase and the recovery rate of the left ventricular function, including cardiac output, LVDP and +/- dp/dt(max), were significantly increased compared with those in I/R group (P < 0.05). By contrast, there were no significant changes between I/R DPC group and I/R group in diabetic rats (P > 0.05).</p><p><b>CONCLUSION</b>Diabetes counteracts the protective effect of the diazoxide preconditioning on ischemic reperfused rat heart, which may be related with acute insulin resistance in cardiomyocytes.</p>

[Effects of phenylephrine, calcium, Acetylcholine and Diazoxide on isolated Aorta of preeclamptic rats]

Preeclampsia, one of the most significant health problems in human pregnancy, is a leading cause of fetal mortality and maternal death. Alteration in vascular response to vasopressors and vasodilators is proposed as a major change in the context of preeclampsia. The aim of the present study was to investigate the responsiveness of preeclamptic rat aorta to some vasopressors and vasodilators. This experimental study was carried out in the pharmacology department of Shiraz University of Medical Sciences in 2008. Thirty pregnant rats were randomly divided into two groups [15 rats in each group]: case group received L-NAME at a dose of 50 mg/kg through drinking water from day 11 of pregnancy. Control group received only tap water. On the 22[nd] gestational day, all rats were anesthetized and killed; thoracic aorta was isolated, cut into 2-3 mm rings and mounted in organ bath. The isolated aortic rings were then exposed to cumulative concentrations of phenylepherine [Ph] and calcium, separately and contractions were measured by isometric transducers. To study the relaxing responses of aortic segments to vasodilators, the effects of cumulative concentrations of acetylcholine [Ach] and diazoxide on aortic rings precontracted with Ph and potassium were recorded, respectively. SPSS software and unpaired T-Test were used for data analysis. Potency of phenyepherine to contract rat aorta was significantly higher in preeclamptic rats compared to normal pregnant group [P= 0.014] but there was no significant difference in Ph-induced maximum contraction between two groups. Potency of Ach and its maximum relaxation effect was significantly lower in preeclamptic rats compared to controls, [p values were 0.026 and 0.004, respectively]. There were no statistically significant differences in the contractile responses of calcium and relaxing effects of diazoxide between two groups. Experimental preeclampsia increases the sensitivity of rat aorta to alpha- adrenergic receptor agonists and decreases the endothelium-dependent relaxation of it. It seems that the functions of voltage-operated calcium channels and ATP-dependent potassium channels do not change in experimental preeclampsia