Beta-cell Function In Children Research Articles

#2623 Homeostatic Model Assessment (HOMA) in pediatric patients with nephrotic syndrome receiving tacrolimus

Abstract Background and Aims Children with nephrotic syndrome (NS) receive diabetogenic drugs like tacrolimus (TAC) and steroids. TAC is toxic to pancreatic β-cells and suppresses insulin production in a time and dose dependent manner. This is well documented in renal transplant patients who develop post-transplant diabetes mellitus (PTDM). Although overt diabetes is uncommon in children receiving TAC for NS, the subclinical effect on β cell function has not been studied. Our aim was to study pancreatic beta cell function as assessed by homeostasis model assessment (HOMA) indices in children with NS who received TAC therapy for at least 1 year duration. Method We performed a prospective descriptive study where we followed children (1-18 years) with NS who received TAC therapy for at least 1 year. We noted patient demographics, clinical and histologic pattern of NS, cumulative steroid dose (mg/kg/day) received 90 days prior and TAC C0 levels. Fasting insulin, blood sugar to calculate HOMA indices for IR (insulin resistance), HOMA % β for beta cell function, HOMA-IS (insulin sensitivity), C-peptide and HbA1C were done once at study inclusion and yearly intervals when required. Statistical analysis included Pearson's correlation, paired t test and regression analysis. Results We performed HOMA indices in 37 children (19 males, 18 females) between September 2021-February 2023. Six patients had 2 measurements during the study period. The mean age of onset of NS was 28 months (95% CI [20; 36]) and mean age at HOMA indices measurement was 69 months (95% CI [59; 79]). Of the 37 patients, 54% (20/37) had late steroid resistance, 32% (12/37) had early steroid resistance, 8% (3/37) had steroid dependent NS, 6% (2/37) had frequently relapsing NS. Kidney biopsy performed in 36 children showed minimal change disease in 55.5% (20/36) and focal segmental glomerulosclerosis in 44.5% (16/36). The mean TAC duration, TAC Co level and mean cumulative steroid dose received in last 90 days were 27 months (95% CI [22;32]), 4.54 ng/ml (95% CI [4.12;4.97]) and 0.36 mg/kg/d (95% CI [0.28;0.44]) respectively. Eleven (30%) patients had cutaneous signs of insulin resistance like acanthosis nigricans and 9 (24%) patients had fasting blood sugar of >100 mg/dl. In Pearson's correlation analysis we found positive correlation between TAC Co level, HOMA IR (r = 0.4, P = 0.008) and TAC Co, HOMA %β (r = 0.44, P = 0.003) and cumulative steroid dose, fasting blood glucose (r = 0.3, P = 0.46). There was negative correlation between TAC Co level, HOMA IS (r = −0.4, P = 0.007). In regression analysis, only TAC Co level significantly influenced all HOMA indices including insulin resistance, insulin sensitivity and beta cell function. A HbA1C of > 5.7 (pre-diabetes range) was found in 32.4% (12/37) patients which warrants further monitoring. C-peptide levels were significantly higher after 12 months of TAC therapy in 6 patients who had two measurements (p = 0.032). Conclusion Tacrolimus therapy for nephrotic syndrome in children can affect pancreatic beta cell function as assessed by HOMA indices. Long term monitoring of pancreatic beta cell function in children with NS on TAC is needed to assess the full extent of these subclinical alterations.

Prolonged Remission Induced by FENofibrate in children with newly diagnosed type 1 diabetes (PRIFEN): protocol of a randomised controlled trial

IntroductionSphingolipids regulate proinsulin folding, insulin secretion and control beta cells apoptosis. Recent evidence has demonstrated that, among other factors, reduced amounts of sulfatide may be relevant in the development of...

Islet autoantibodies and residual beta-cell function in children with type 1 diabetes depending on age of manifestation

BACKGROUND: Type 1 diabetes mellitus (T1D) is an autoimmune disorder that leads to pancreatic β-cells destruction and progressive decrease of insulin secretion. Specific islet autoantibodies (AAbs) are the main diagnostic marker of T1D. Residual β-cell function, as measured by C-peptide, has repeatedly been demonstrated to be clinically important.AIM: To study the frequency and levels of residual C-peptide secretion and persistence of pancreatic AAbs in children with T1D with different duration and age of manifestation of the disease.MATERIALS AND METHODS: The levels of C-peptide and AAbs to ZnT8 (zinc transporter 8), AAbs to IA-2 (Insulinoma Antigen 2), AAbs to GAD (Glutamate Decarboxylase), IAA (insulin autoantibodies) were measured. Patients were divided into 3 groups depending on the duration of T1D (1st — <1 year, 2nd — from 1 to 5 years, 3rd — >5 years) and age of manifestation (A — prepubertal and B — puberty).RESULTS: The median duration of T1D was 1.8 [0,8;3,9], 76.3% out of 1333 patients were seropositive, 40% had residual levels of C-peptide. With disease duration there were a decrease in AAbs+: 1st group 74%, 2nd group 69%, and 3rd group 48%. In all groups, percentage of patients with positive levels of one or more AAbs was significantly higher in children with T1D manifestation at puberty. GADA and ZnT8A were more common in the first year of the disease. IA-2A were observed with the same frequency in the group of adolescents. IAA were more common in patients at prepubertal age. An undetectable level of C-peptide was observed significantly higher in children with T1D manifestation in prepubertal age (p<0.05): 1А — 13% and 1B — 5%, 2А — 51% and 2B — 14%, 3А — 82% and 3B — 50%, reference range of C-peptide was observed in adolescents (p<0,05): 1А — 6% and 1B — 44%, 2А — 2% and 2b — 25%, 3А — 2% and 3B — 11%.CONCLUSION: AAbs+ is relatively common in children with T1D and about half of them are seropositive in more than 5 years after manifestation. GADA and ZnT8A have high specificity for patients with new-onset T1D. C-peptide secretion depends on the age of the disease manifestation.

Effect of Verapamil on Pancreatic Beta Cell Function in Newly Diagnosed Pediatric Type 1 Diabetes

In preclinical studies, thioredoxin-interacting protein overexpression induces pancreatic beta cell apoptosis and is involved in glucotoxicity-induced beta cell death. Calcium channel blockers reduce these effects and may be beneficial to beta cell preservation in type 1 diabetes. To determine the effect of verapamil on pancreatic beta cell function in children and adolescents with newly diagnosed type 1 diabetes. This double-blind, randomized clinical trial including children and adolescents aged 7 to 17 years with newly diagnosed type 1 diabetes who weighed 30 kg or greater was conducted at 6 centers in the US (randomized participants between July 20, 2020, and October 13, 2021) and follow-up was completed on September 15, 2022. Participants were randomly assigned 1:1 to once-daily oral verapamil (n = 47) or placebo (n = 41) as part of a factorial design in which participants also were assigned to receive either intensive diabetes management or standard diabetes care. The primary outcome was area under the curve values for C-peptide level (a measure of pancreatic beta cell function) stimulated by a mixed-meal tolerance test at 52 weeks from diagnosis of type 1 diabetes. Among 88 participants (mean age, 12.7 [SD, 2.4] years; 36 were female [41%]; and the mean time from diagnosis to randomization was 24 [SD, 4] days), 83 (94%) completed the trial. In the verapamil group, the mean C-peptide area under the curve was 0.66 pmol/mL at baseline and 0.65 pmol/mL at 52 weeks compared with 0.60 pmol/mL at baseline and 0.44 pmol/mL at 52 weeks in the placebo group (adjusted between-group difference, 0.14 pmol/mL [95% CI, 0.01 to 0.27 pmol/mL]; P = .04). This equates to a 30% higher C-peptide level at 52 weeks with verapamil. The percentage of participants with a 52-week peak C-peptide level of 0.2 pmol/mL or greater was 95% (41 of 43 participants) in the verapamil group vs 71% (27 of 38 participants) in the placebo group. At 52 weeks, hemoglobin A1c was 6.6% in the verapamil group vs 6.9% in the placebo group (adjusted between-group difference, -0.3% [95% CI, -1.0% to 0.4%]). Eight participants (17%) in the verapamil group and 8 participants (20%) in the placebo group had a nonserious adverse event considered to be related to treatment. In children and adolescents with newly diagnosed type 1 diabetes, verapamil partially preserved stimulated C-peptide secretion at 52 weeks from diagnosis compared with placebo. Further studies are needed to determine the longitudinal durability of C-peptide improvement and the optimal length of therapy. ClinicalTrials.gov Identifier: NCT04233034.

Higher risk of severe hypoglycemia in children and adolescents with a rapid loss of C-peptide during the first 6 years after type 1 diabetes diagnosis

IntroductionThe progression to insulin deficiency in type 1 diabetes is heterogenous. This study aimed to identify early characteristics associated with rapid or slow decline of beta-cell function and how it...

Impact of CFTR Modulators on Beta-Cell Function in Children and Young Adults with Cystic Fibrosis.

Background: To date, no consistent data are available on the possible impact of CFTR modulators on glucose metabolism. The aim of this study was to test the hypothesis that treatment with CFTR modulators is associated with an improvement in the key direct determinants of glucose regulation in children and young adults affected by Cystic Fibrosis (CF). Methods: In this study, 21 CF patients aged 10–25 underwent oral glucose tolerance test (OGTT) before and after 12–18 months of treatment with Lumacaftor/Ivacaftor or Elexacaftor-Ivacaftor-Tezacaftor. β-cell function (i.e., first and second phase of insulin secretion measured as derivative and proportional control, respectively) and insulin clearance were estimated by OGTT mathematical modelling. Insulin sensitivity was estimated by the Oral Glucose Sensitivity Index (OGIS). The dynamic interplay between β-cell function, insulin clearance and insulin sensitivity was analysed by vector plots of glucose-stimulated insulin bioavailability vs. insulin sensitivity. Results: No changes in glucose tolerance occurred after either treatment, whereas a significant improvement in pulmonary function and chronic bacterial infection was observed. Beta cell function and insulin clearance did not change in both treatment groups. Insulin sensitivity worsened in the Lumacaftor/Ivacaftor group. The analysis of vector plots confirmed that glucose regulation was stable in both groups. Conclusions: Treatment of CF patients with CFTR modulators does not significantly ameliorate glucose homeostasis and/or any of its direct determinants.

Relationship between glucose homeostasis and obesity in early life-a study of Italian children and adolescents.

Epidemic obesity is the most important risk factor for prediabetes and type 2 diabetes (T2D) in youth as it is in adults. Obesity shares pathophysiological mechanisms with T2D and is likely to share part of the genetic background. We aimed to test if weighted genetic risk scores (GRSs) for T2D, fasting glucose (FG) and fasting insulin (FI) predict glycaemic traits and if there is a causal relationship between obesity and impaired glucose metabolism in children and adolescents. Genotyping of 42 SNPs established by genome-wide association studies for T2D, FG and FI was performed in 1660 Italian youths aged between 2 and 19 years. We defined GRS for T2D, FG and FI and tested their effects on glycaemic traits, including FG, FI, indices of insulin resistance/beta cell function and body mass index (BMI). We evaluated causal relationships between obesity and FG/FI using one-sample Mendelian randomization analyses in both directions. GRS-FG was associated with FG (beta = 0.075 mmol/l, SE = 0.011, P = 1.58 × 10−11) and beta cell function (beta = −0.041, SE = 0.0090 P = 5.13 × 10−6). GRS-T2D also demonstrated an association with beta cell function (beta = −0.020, SE = 0.021 P = 0.030). We detected a causal effect of increased BMI on levels of FI in Italian youths (beta = 0.31 ln (pmol/l), 95%CI [0.078, 0.54], P = 0.0085), while there was no effect of FG/FI levels on BMI. Our results demonstrate that the glycaemic and T2D risk genetic variants contribute to higher FG and FI levels and decreased beta cell function in children and adolescents. The causal effects of adiposity on increased insulin resistance are detectable from childhood age.

Lack of effect of Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12 on beta-cell function in children with newly diagnosed type 1 diabetes: a randomised controlled trial

IntroductionThe gut microbiota may be relevant in the development of type 1 diabetes (T1D). We examined the effects of Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12 on beta-cell function in...

Role of vitamin D and vitamin D receptor gene polymorphisms on residual beta cell function in children with type 1 diabetes mellitus.

After the onset of type 1 diabetes mellitus (T1DM), preservation of the residual ß-cell function can help good metabolic control. The aim of this study was to evaluate the effect of vitamin D and its receptor gene polymorphisms on residual ß-cells function. One hundred and one children with T1DM (new cases) older than 5 years were selected. Vitamin D receptor (VDR) gene polymorphisms, vitamin D (VD), fasting and stimulated C-peptide (FCP and SCP) levels were measured within 1.5 and 4.5 month after the diagnosis of disease. Kruskal-Wallis and Mann-whitney U test were used for comparing the study groups. Generalized estimating equation (GEE) model was used for the estimation of association between VD and VDR gene polymorphisms with FCP and SCP after adjustment for comorbid variables. The most frequent genotypes and alleles in TaqI, FokI, BsmI and ApaI polymorphisms were TT (50%) and allele T (68.88%), FF (59.2%) and allele F (77.04%), Bb (41.8%) and allele b (61.73%), and Aa (53.1%) and allele A (63.29%) respectively. In children with higher VD levels, the C-peptide (CP) levels were elevated. Also we observed: the tt genotype associated with increasing SCP levels compared with TT genotype; the bb and Bb genotypes were associated with increasing both FCP and SCP in comparison to BB; and the aa and Aa genotypes were associated with decreasing FCP in comparison to the AA genotype. Sufficient levels of VD (more than 30 ng/ml) can preserve residual ß-cells and insulin secretion.

Plasma lipid species at type 1 diabetes onset predict residual beta-cell function after 6 months

IntroductionThe identification of metabolomic dysregulation appears promising for the prediction of type 1 diabetes and may also reveal metabolic pathways leading to beta-cell destruction. Recent studies indicate that regulation of multiple phospholipids precede the presence of autoantigens in the development of type 1 diabetes.ObjectivesWe hypothesize that lipid biomarkers in plasma from children with recent onset type 1 diabetes will reflect their remaining beta-cell function and predict future changes in beta-cell function.MethodsWe performed targeted lipidomic profiling by electrospray ionization tandem mass spectrometry to acquire comparative measures of 354 lipid species covering 25 lipid classes and subclasses in plasma samples from 123 patients < 17 years of age followed prospectively at 1, 3, 6 and 12 months after diagnosis. Lipidomic profiles were analysed using liner regression to investigate the relationship between plasma lipids and meal stimulated C-peptide levels at each time point. P-values were corrected for multiple comparisons by the method of Benjamini and Hochberg.ResultsLinear regression analysis showed that the relative levels of cholesteryl ester, diacylglycerol and triacylglycerol at 1 month were associated to the change in c-peptide levels from 1 to 6 months (corrected p-values of 4.06E−03, 1.72E−02 and 1.72E02, respectively). Medium chain saturated and monounsaturated fatty acids were the major constituents of the di- and triacylglycerol species suggesting a link with increased lipogenesis.ConclusionThese observations support the hypothesis of lipid disturbances as explanatory factors for residual beta-cell function in children with new onset type 1 diabetes.

Effects of Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12 on beta-cell function in children with newly diagnosed type 1 diabetes: protocol of a randomised controlled trial

IntroductionRecent evidence has demonstrated that, among other factors, dysbiosis (imbalances in the composition and function of the gut microbiota) may be relevant in the development of type 1 diabetes (T1D)....

Assessment of preservation of beta-cell function in children with long-standing type 1 diabetes with „ultrasensitive c-peptide” method

Type 1 diabetes mellitus is a disease caused by the autoimmune destruction of pancreatic beta-cells. It was previously believed that the loss of the endocrine function of the pancreas is total and inevitable. With the rise of new knowledge and new methods allowing to reliably measure c-peptide in the low plasma concentration range, we have learned otherwise. Some residual function of the beta-cells can be present even after decades of the course of the disease. The aim of the study was to evaluate the c-peptide level with routine laboratory and ultrasensitive methods in children with long-standing type 1 diabetes in relation to clinical characteristics. We recruited 178 consecutive children with type 1 diabetes mellitus lasting at least 1 year, mean diabetes duration was 5.6 years. Basic anthropometric measurements were performed and blood samples were drawn. From patients history records we gathered data regarding the course of the disease and laboratory results previously acquired. Laboratory tests performed on the blood samples included HbA1c levels and c-peptide level measurement using classic (n=178) and ultrasensitive (n=160) method (Mercodia). Clinically relevant c-peptide level was set at 0.23 ng/ml according to the DCCT recommendations. Clinically relevant c-peptide was found in 54 of 160 (33.75%) patients. Patients with preserved c-peptide were older at the time of diagnosis, had longer clinical remission, and required lower total and basal doses of insulin. Significantly lower mean HbA1c from the last year, but higher HbA1c at the time of the diabetes diagnosis were found in the group with higher c-peptide levels. The comparison of the classic and ultrasensitive c-peptide tests revealed that both yield similar results. Our observation shows that 34% of young patients with long-standing type 1 diabetes have prolonged c-peptide secretion. We confirm the long-standing assumption that residual beta-cell function is beneficial for metabolic control of the patients. Classic method of the c-peptide measurement can be just as useful in clinical practice as the ultrasensitive one.

Antibody Response to Serpin B13 Induces Adaptive Changes in Mouse Pancreatic Islets and Slows Down the Decline in the Residual Beta Cell Function in Children with Recent Onset of Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1D) is characterized by a heightened antibody (Ab) response to pancreatic islet self-antigens, which is a biomarker of progressive islet pathology. We recently identified a novel antibody to clade B serpin that reduces islet-associated T cell accumulation and is linked to the delayed onset of T1D. As natural immunity to clade B arises early in life, we hypothesized that it may influence islet development during that time. To test this possibility healthy young Balb/c male mice were injected with serpin B13 mAb or IgG control and examined for the number and cellularity of pancreatic islets by immunofluorescence and FACS. Beta cell proliferation was assessed by measuring nucleotide analog 5-ethynyl-2'-deoxyuridine (5-EdU) incorporation into the DNA and islet Reg gene expression was measured by real time PCR. Human studies involved measuring anti-serpin B13 autoantibodies by Luminex. We found that injecting anti-serpin B13 monoclonal Ab enhanced beta cell proliferation and Reg gene expression, induced the generation of ∼80 pancreatic islets per animal, and ultimately led to increase in the beta cell mass. These findings are relevant to human T1D because our analysis of subjects just diagnosed with T1D revealed an association between baseline anti-serpin activity and slower residual beta cell function decline in the first year after the onset of diabetes. Our findings reveal a new role for the anti-serpin immunological response in promoting adaptive changes in the endocrine pancreas and suggests that enhancement of this response could potentially help impede the progression of T1D in humans.

Early origins of diabetes: an update from the EarlyBird study

The EarlyBird diabetes study has followed over 300 healthy children and their parents for 12 years. The aim has been to understand which children would be most at risk of adult onset diabetes. Repeated measures in the same individuals reveal trends which may be associated with diabetes risk, and will help determine the direction of causality. This report draws on 12 years of EarlyBird data, giving an insight into diabetes risk in three areas: • Trends in both insulin supply (secretion) and demand (tissue resistance) over the period of pubertal development affect diabetes risk. This paper compares insulin resistance and beta cell function in children who develop impaired fasting glucose with those whose glucose levels remain within the normal range.• Epigenetics is a new area of research. While genetic make-up cannot change, the way genes are expressed (turned on or off) can vary in relation to environmental stressors. This paper reviews preliminary analyses of epigenetic variation in a gene associated with diabetes risk, and how this variation affects adiposity during childhood.• The association between low mood (tendency towards depression) and diabetes risk in teenagers is explored.

Evidence of early beta-cell deficiency among children who show impaired fasting glucose: 10-yr cohort study (EarlyBird 56)

Impaired fasting glucose (IFG) is a predictor of future diabetes and is increasingly common in children, but the extent to which it results from excess insulin demand or failure of supply is unclear. Our aim was to compare the behaviour of insulin sensitivity and beta-cell function in children who developed IFG with those whose glucose levels remained within the normal range. We examined trends in fasting glucose, insulin sensitivity (HOMA-S) and beta-cell function (HOMA-B) in 327 healthy children annually from 5 to 15 yr, and the parents at baseline. Fifty-five children showed IFG, mostly after age 11 yr. Fasting glucose rose progressively and was higher throughout in those who developed IFG compared with those who did not (p < 0.001). Beta-cell function was lower from the age of 5 yr in those who developed IFG (p = 0.006), but there was no difference in BMI (p = 0.71). A difference in insulin sensitivity was revealed on adjustment for covariates (p = 0.03). Glucose was higher (p < 0.001), beta-cell function lower (p = 0.01), and insulin sensitivity the same (p = 0.86) in the mothers of children who showed IFG, compared with those who did not. IFG is common in contemporary children, and appears to be related to a defect in beta-cell function already present at 5 yr. Similar findings in the mothers of IFG children suggest that the beta-cell defect may be transmissible.

A randomized placebo-controlled trial of alphacalcidol on the preservation of beta cell function in children with recent onset type 1 diabetes

This participant-blinded parallel-group randomized placebo-controlled study demonstrated that alfacalcidol (vitamin D analogue) preserves beta cell function in newly diagnosed type 1 diabetes (T1DM) in children. Subjects from outpatient clinic were randomized to intervention and control groups. Inclusion: (1) age 8-15, (2) T1DM, (3) duration <8 weeks, (4) no chronic diseases, (5) stable diet. Exclusion: (1) vitamin D, calcium supplements or fortified foods, (2) hypercalcemia. Intervention group received alfacalcidol 0.25 μg twice daily, while control group received placebo. Insulin given physician-titrated to blood glucose. Safety monitored by serum calcium and phosphate. Beta cell function assessed at 0, 3, 6 months using fasting C-peptide (FCP) and daily insulin dosage per body weight (DID). Primary outcome measured using multivariate repeated measures GLM-ANOVA, with FCP and DID as primary measures and age, gender, sunlight exposure, 25-hydroxy vitamin D, and HbA1c as covariates. Of 61 subjects, 7 dropped out. GLM-ANOVA showed that groups were different (p=0.019, Eta-squared=0.087), with no significant covariates. FCP was higher and DID lower in the intervention group, with males having stronger responses to alfacalcidol (p=0.001). No adverse effects were observed. The study confirmed that alfacalcidol can safely preserve beta cell function in newly diagnosed T1DM in children, with a stronger effect in males. IRCT201205159753N1.

C-peptide in the classification of diabetes in children and adolescents

To report C-peptide results in newly diagnosed patients and the relation to clinical diagnosis of diabetes. A nation-wide cohort, the Better Diabetes Diagnosis study was used to determine serum C-peptide at diagnosis in 2734 children and adolescents. Clinical data were collected at diagnosis and follow-up. C-peptide was determined in a validated and controlled time-resolved fluoroimmunoassay. The clinical classification of diabetes, before any information on human leukocyte antigen, islet autoantibodies, or C-peptide was received, was type 1 diabetes (T1D) in 93%, type 2 diabetes (T2D) in 1.9%, maturity onset diabetes of the young (MODY) in 0.8%, secondary diabetes (0.6%), while 3.3% could not be classified. In a random, non-fasting serum sample at diagnosis, 56% of the patients had a C-peptide value >0.2 nmol/L. Children classified as T2D had the highest mean C-peptide (1.83 + 1.23 nmol/L) followed by MODY (1.04 ± 0.71 nmol/L) and T1D (0.28 ± 0.25 nmol/L). Only 1/1037 children who had C-peptide <0.2 nmol/L at diagnosis was classified with a type of diabetes other than T1D. Predictive value of C-peptide >1.0 nmol/L for the classification of either T2D or MODY was 0.46 [confidence interval 0.37-0.58]. More than half of children with newly diagnosed diabetes have clinically important residual beta-cell function. As the clinical diagnosis is not always straightforward, a random C-peptide taken at diagnosis may help to classify diabetes. There is an obvious use for C-peptide determinations to evaluate beta-cell function in children with diabetes.

The nuclear receptor coactivator AIB3 is a modulator of HOMA β‐cell function in nondiabetic children

The amplified in breast cancer-3 protein (AIB3) is a nuclear coactivator involved in proliferation, apoptosis and development. AIB3 loss of function causes deficient insulin secretion in mice, indicating that AIB3 participates in beta-cell regulation. Our objective was to evaluate genetic variants located on AIB3 associated with beta-cell function in children and to analyse the effect of AIB3 overexpression on gene expression in insulin 1 (INS-1) beta-pancreatic cells. Polymorphisms from AIB3 were genotyped in 148 children with normal or low birthweights for gestational age. The effect of AIB3 overexpression on gene expression was analysed by real-time polymerase chain reaction (PCR) in INS-1 cells. AIB3 variants were associated with homeostasis model assessment of beta-cell function (HOMA-beta-cell) in children with normal or low birthweights for gestational age, but not with HOMA of insulin resistance (HOMA-IR), or with birthweight. AIB3 overexpression increased the expression of genes involved in signalling, such as IRS-1, IRS-2, IGF-II receptor or Foxo1, or of genes that control insulin secretion, such as Cplx2, Glut2 or Kv3.1 in INS-1 cells. Our results suggest that AIB3 contributes to the maintenance of beta-cell function in nondiabetic children and regulates gene expression in INS-1 cells.

Evaluation of β-cell function in diabetic Taiwanese children using a 6-min glucagon test

This study evaluates the effects of glucagon 30 mug/kg (maximal 1 mg) on beta-cell function in children by C-peptide determined before and 6 min after intravenous administration. From 1990 to 2005, 118 Taiwanese children with newly diagnosed diabetes mellitus (98 children with type 1 and 20 children with type 2) and 29 normal Taiwanese children were enrolled in this study. Fasting and 6-min post-glucagon C-peptide levels were analyzed. In the pre-pubertal group, the median fasting serum C-peptide levels were 0.2 and 0.8 nmol/l in type 1 diabetes and normal children, respectively. These levels rose to 0.3 and 1.9 nmol/l after glucagon stimulation. In the pubertal group, the median fasting serum C-peptide levels were 0.3, 1.0 and 0.9 nmol/l in type 1 diabetes, type 2 diabetes and normal children, respectively. They rose to 0.4, 2.5 and 2.7 nmol/l after glucagon stimulation. Both fasting and post-glucagon C-peptide levels in type 1 diabetes patients were significantly lower than those of normal children and children with type 2 diabetes. The optimal cut-off values to distinguish type 1 diabetes patients from those with type 2 as determined by the receiving operating characteristic curve were 0.7 and 1.1 nmol/l, respectively. The sensitivities of both C-peptide values were 93%. The post-glucagon C-peptide level was more powerful in distinguishing type 1 diabetes from type 2 diabetes with higher specificity (95% vs. 85%). The 6-min glucagon test is valuable in assessing beta-cell function in children and can help pediatricians in the differential diagnoses of diabetes mellitus in children.

Factors predicting residual beta cell function in children with newly-diagnosed type 1 diabetes

Factors predicting residual beta cell function in children with newly-diagnosed type 1 diabetes