Endocrine Management and Clinical Outcomes in a Cohort of Pediatric Patients Undergoing Total Pancreatectomy with Islet Autotransplantation

Objective: To describe management strategies that contributed to optimal outcomes in pediatric recipients of a total pancreatectomy with islet autotransplantation (TPIAT). Research Design and Methods: We provide a comprehensive report of the approach to endocrine management of the pediatric TPIAT recipient from initial evaluation through the first 4 years postsurgery. We performed a retrospective review of the endocrine outcomes of TPIAT recipients to describe the impact of this approach on post-TPIAT glycemic management. Results: Outcome data from 86 TPIAT recipients were reviewed. At 12 months post-TPIAT (n = 82), the median HbA1C was 6.0% (25-75th percentile 5.6-6.7), at 18 months (n = 56) HbA1C was 6.4% (5.6-7.5), at 2 years (n = 46) HbA1C was 6.4% (5.6-7.4), at 3 years (n = 31) HbA1C was 6.5% (5.5-8.1), and at 4 years (n = 16) HbA1C was 7.2% (6.2-8.3). Conclusions: Pediatric patients at our institution have favorable endocrine outcomes as evidenced by median HbA1C under the goal of 6.5% through the initial 3 years by following our modified management protocols.

Association of pancreatic fat on imaging with pediatric metabolic co-morbidities

BACKGROUND

The relationship between pancreatic fat on imaging and metabolic co-morbidities has not been established in pediatrics. We sought to investigate the relationship between pancreatic fat measured by MRI and endocrine/exocrine dysfunctions along with the metabolic co-morbidities in a cohort of children.

OBJECTIVE

To investigate relationships between pancreatic fat quantified by MRI and endocrine and exocrine conditions and metabolic co-morbidities in a cohort of children. MATERIALS AND METHODS: This was a retrospective review of pediatric patients (n = 187) who had a clinically indicated MRI examination between May 2018 and February 2020. After 51 patients without useable imaging data were excluded, the remaining 136 subjects comprised the study sample. Laboratory studies were assessed if collected within 6 months of MRI and patient charts were reviewed for demographic and clinical information. MRI proton density fat fraction (PDFF) sequence had been acquired according to manufacturer's specified parameters at a slice thickness of 3 mm. Two blinded radiologists independently collected PDFF data.

RESULTS

The median age at MRI was 12.1 (IQR: 9.0-14.8) years and the majority of patients were Caucasian (79%), followed by African American and Hispanic at 12% and 11% respectively. There was a higher median pancreas fat fraction in patients with exocrine conditions (chronic pancreatitis or exocrine insufficiency) compared to those without (3.5% vs 2.2%, p = 0.03). There was also a higher median fat fraction in the head of pancreas in patients with endocrine insufficient conditions (insulin resistance, pre-diabetes, type 1 and type 2 diabetes) compared to those without endocrine insufficiency when excluding patients with active acute pancreatitis (3.5% vs 2.0%, p = 0.04). Patients with BMI > 85% had higher mean fat fraction compared to patients with BMI ≤ 85% (head: 3.8 vs 2.4%, p = 0.01; body: 3.8 vs 2.5%, p = 0.005; tail: 3.7 vs 2.7%, p = 0.049; overall pancreas fat fraction: 3.8 vs 2.6%, p = 0.002).

CONCLUSION

Pancreas fat is elevated in patients with BMI > 85% and in those with exocrine and endocrine insufficiencies.

Is There a Benefit From Islet Autotransplantation in Patients With Type 1 Diabetes Mellitus Undergoing Total Pancreatectomy?

ABSTRACT

Children with acute recurrent and chronic pancreatitis (CP) experience abdominal pain that leads to hospitalizations, opioid dependence, and poor quality of life. Total pancreatectomy with islet autotransplantation (TPIAT) is offered as a surgical option in management of debilitating pancreatitis that fails medical and endoscopic therapy to reduce or eliminate pain. Given that patients with type 1 diabetes mellitus (T1DM) lack insulin-producing β cells, the outcomes from autotransplanting islet isolates back into total pancreatectomy patients with T1DM are not fully known.We performed TPIAT in 2 CP patients who also had a diagnosis of T1DM for at least 6 years before the operation and evaluated the clinical and laboratory outcomes before and after the operation. Postoperatively both patients' abdominal pain had significantly subsided, they were weaned off opioid medications, and they were able to return to full-time school attendance. In addition, total daily dose of insulin in 1 patient was able to be slightly reduced at 12 months post-TPIAT. We observed in vitro that residual α cells and β cells in T1DM islets were able to secrete a small amount of glucagon and insulin, respectively.

Predictors of Glycemic Outcomes at 1 Year Following Pediatric Total Pancreatectomy With Islet Autotransplantation

OBJECTIVE

Total pancreatectomy with islet autotransplantation (TPIAT) is indicated to alleviate debilitating pancreas-related pain and mitigate diabetes in patients with acute recurrent and chronic pancreatitis when medical/endoscopic therapies fail. Our aim was to evaluate predictors of insulin requirement at 1 year following TPIAT in a cohort of children.

RESEARCH DESIGN AND METHODS

This was a review of 43 pediatric patients followed after TPIAT for 1 year or longer. Primary outcome was insulin use at 1 year, categorized as follows: insulin independent, low insulin requirement (<0.5 units/kg/day), or high insulin requirement (≥0.5 units/kg/day).

RESULTS

At 1 year after TPIAT, 12 of 41 (29%) patients were insulin independent and 21 of 41 (51%) had low and 8 of 41 (20%) had high insulin requirement. Insulin-independent patients were younger than those with low and high insulin requirement (median age 8.2 vs. 14.6 vs. 13.1 years, respectively; P = 0.03). Patients with insulin independence had a higher number of transplanted islet equivalents (IEQ) per kilogram body weight (P = 0.03) and smaller body surface area (P = 0.02), compared with those with insulin dependence. Preoperative exocrine insufficiency was associated with high insulin requirement (P = 0.03). Higher peak C-peptide measured by stimulated mixed-meal tolerance testing (MMTT) at 3 and 6 months post-TPIAT was predictive of lower insulin requirement at 1 year (P = 0.006 and 0.03, respectively).

CONCLUSIONS

We conclude that insulin independence following pediatric TPIAT is multifactorial and associated with younger age, higher IEQ per kilogram body weight transplanted, and smaller body surface area at time of operation. Higher peak C-peptide measured by MMTT following TPIAT confers a higher likelihood of low insulin requirement.

Inaccurate Glucose Sensor Values After Hydroxyurea Administration

Objective: To assess the degree, duration, mean absolute relative difference (MARD), and error analysis of discrepant values per continuous glucose monitoring (CGM) systems after hydroxyurea (HU) administration. Research Design and Methods: Inpatient glucometer and CGM data from 16 total pancreatectomy/islet autotransplantation patients using Dexcom Professional G4 and 12 patients using Dexcom G6 were analyzed after daily dosing with HU. Timing of HU dosing and median of 9.5 days of sensor and glucometer values were assessed per patient. Results: A large positive elevation of sensor readings was identified after HU dosing. The greatest discrepancy between glucometer and sensor readings occurred 0.5-2 h after HU administration [G4 (mean 3.0 mmol/L, median 2.4 mmol/L, MARD 55%), G6 (mean 4.2 mmol/L, median 4.6 mmol/L, MARD 91%)]. The discrepancy was <1.1 mmol/L, mean (-0.5 mmol/L) and median (-0.5 mmol/L), MARD 14% (G4) and <1.1 mmol/L, mean (0.3 mmol/L) and median (0.3 mmol/L), MARD 17% (G6), by 6 h after administration. Error analysis with the G6 system found 94% of pairs in clinically acceptable range by 6-9 h after HU administration. Aspirin, also given once daily, did not result in glucose value discrepancy with the G6 system but variability was observed with the G4 system. Conclusions: There was marked elevation of sensor glucose readings compared with glucometer values [up to 13.9 mmol/L (G4), 13 mmol/L (G6)] from 0.5 to 6 h after HU administration. It is important to counsel a patient using a Dexcom CGM system and HU therapy on this finding and to advise reliance on glucometer testing for accurate glucose assessment up to 6-9 h after HU administration.

Improved Glycemic Outcomes with Early Initiation of Insulin Pump Therapy in Pediatric Postoperative Total Pancreatectomy with Islet Autotransplantation

Total pancreatectomy with islet autotransplantation (TPIAT) is a surgical procedure for patients with chronic pancreatitis and poor quality of life. Euglycemia is critical for islet cell survival and engraftment. We reviewed clinical care practice and hypothesized that early in-hospital transition from intravenous insulin to insulin pump therapy, managed by an endocrine unit trained on post-surgical care, would improve glucose control and impact the length of hospital stay. We completed a retrospective analysis of 40 pediatric patients who underwent TPIAT. Comparative hospitalized postoperative groups included those who received insulin intravenously, followed by multiple daily injections, subsequently managed by pump therapy (n = 14), versus those who received insulin intravenously followed by early pump therapy provided on the endocrine unit trained to manage post-surgical patients (n = 26). The outcomes analyzed included percentage of blood glucoses in target (4.44–6.66 mmol/L (80–120 mg/dL)), hypoglycemia (<3.33 mmol/L (<60 mg/dL)) and hyperglycemia (>7.77 mmol/L (>140 mg/dL)), blood glucose variability, and length of hospital unit stay post-ICU. Hospitalized patients with early transition to pump therapy on a specialized endocrine unit had a higher proportion of glucose values in the target range (61% vs. 51%, p = 0.0003), a lower proportion of hyperglycemia (15% vs. 19%, p = 0.04), and a lower proportion of hypoglycemia, though not statistically significant (3.4% vs. 4.4%, p = 0.33). Early pump users also had lower variability in glucose values over 10 days post-intravenous insulin (p = 0.001), and the post-transition median length of stay was shorter by 5 days (median: 11.5 vs. 16.5 days, p = 0.005). Early in-hospital pump therapy managed by the specialized endocrine unit improved glucose outcomes and reduced the duration of in-unit stay.

Islet cell transplantation in children

This paper aims to provide an overview of islet cell transplantation in children, with specific attention to pediatric total pancreatectomy with islet autotransplantation (TPIAT). We will summarize the definition and causes of chronic pancreatitis in children, the TPIAT procedure and potential complications, the process of islet cell isolation and autotransplantation, and long-term results after TPIAT. Lastly, we will briefly discuss islet cell allotransplantation in the adult population and its potential role in treating children.

In-hospital and 90-day outcomes after total pancreatectomy with islet autotransplantation for pediatric chronic and acute recurrent pancreatitis

Total pancreatectomy with islet autotransplantation (TPIAT) is used to treat debilitating chronic pancreatitis (CP) and acute recurrent pancreatitis (ARP) that has failed medical and endoscopic therapy. We performed a retrospective review of TPIAT patients at a free-standing children's hospital to evaluate perioperative outcomes. Twenty patients (median age 13, 65% female) underwent TPIAT (2015 through 2017). Of the 20 patients, 95% had CP and 1 patient (5%) had ARP alone. Seventy-five percent of the patients had a pancreatitis-associated genetic mutation; 40% had pancreas divisum. The median surgical time was 757 (IQR 657 to 835) minutes. Median islet equivalents per kg of body weight (IEQ/kg) were 6404 (IQR 5018 to 7554). At 90 days postoperatively vs preoperatively, significantly fewer patients were receiving parenteral nutrition (0% vs 25%, P = .006) and opioids (45% vs 75%, P = .01). Short Form 36-Item Health Survey (SF-36) physical health module scores and total scores improved (34.0 preoperatively vs 54.6 at 90 days, P = .008, and 47.1 vs 65.3, P = .007, respectively); SF-10 physical health scores also improved (13.4 vs 33.1, P = .02). Insulin requirement decreased from 0.5 unit/kg/day to 0.4 unit/kg/day between discharge and 90 days (P = .02). TPIAT is an effective option when debilitating disease persists despite maximal medical and endoscopic therapy. Opioid, parenteral nutrition, and exogenous insulin use can successfully be weaned within 90 days after TPIAT, with gains in health-related quality of life.

Severe fasting hypoglycemia in a child after total pancreatectomy with islet autotransplantation

TPIAT is an increasingly utilized treatment option for select children with CP. Post-TPIAT fasting hypoglycemia, unrelated to exogenous insulin, is a complication recently reported in adults. This phenomenon has not been described in children. We review a case of severe fasting hypoglycemia in an adolescent female occurring 10 months post-TPIAT. A 12-year-old girl underwent TPIAT for CP. Ten months postoperatively she developed recurrent hypoglycemia on a total daily insulin dose of 0.03 units/kg. Consequently, insulin therapy was discontinued. Approximately 20 hours after her last rapid-acting insulin exposure, she had an episode of fasting hypoglycemia (33 mg/dL on glucometer). Her CGM documented two separate, precipitous drops in glucose overnight. The family was instructed to revise her diet, and there were no subsequent episodes of severe, fasting hypoglycemia. This is the first report of fasting hypoglycemia occurring post-TPIAT in a pediatric patient. Use of a CGM allowed for documentation of glucose trends and alarm notification of hypoglycemic events. Dietary changes appeared to help mitigate hypoglycemia recurrence. This report demonstrates that fasting hypoglycemia is a potential complication that should be recognized and safeguarded against in post-TPIAT pediatric patients.

β-Cell Function Over Time in Adolescents With New Type 2 Diabetes and Obese Adolescents Without Diabetes

PURPOSE

The progression of β-cell function in newly diagnosed adolescents with type 2 diabetes mellitus (T2DM) is not well documented. We hypothesized that at the time of diagnosis with T2DM, adolescents would have impaired β-cell function as demonstrated by the disposition index (calculated as: insulin secretion adjusted for insulin sensitivity), and this would be followed by a rapid decline of function despite standard medical management.

METHODS

Thirty-nine adolescents with recently diagnosed T2DM and 32 obese adolescent controls with normal glucose tolerance had acute insulin response to glucose, homeostatic model assessment of insulin resistance, and disposition index measured serially over 2 years.

RESULTS

In the adolescent T2DM group, fasting glucose increased over 2 years (p = .04), while DI was impaired at baseline and showed an overall relative decline of 25% per year. The mean Hemoglobin A_1c remained below 8% (64 mmol/mol). Differences were observed between the T2DM and control adolescents in the way DI changed over time (p = .02).

CONCLUSIONS

β-cell function in adolescents with recently diagnosed T2DM was impaired with no improvement of β-cell function over the 2 years of study despite stable Hemoglobin A_1c, body mass index markers of insulin sensitivity, and standard treatment of hyperglycemia.

Continuous glucose monitoring following pancreatectomy with islet autotransplantation in children

Aim was to determine whether CGM could accurately monitor blood glucose concentration in the immediate postoperative period following pancreatectomy with IAT in children. CGM was used in nine patients undergoing IAT at our institution between April 2015 and September 2016 (eight total pancreatectomy and one subtotal pancreatectomy). MAD and MARD of CGM values compared to time-matched serum blood glucose were calculated during the first 5 days of ICU admission. Goal range was defined as 70-140 mg/dL and out-of-range was >140 mg/dL or <70 mg/dL. Of 89 time-matched measures found, 75% of CGM values were within 15 mg/dL, and 51% were within 10 mg/dL, compared to serum glucose. MAD was 11.6 mg/dL, and MARD was 10.6%. CGM values did not differ from serum glucose (P=.74). By Clarke error grid analysis, 100% of paired values were in clinically acceptable zones. By surveillance error grid analysis, 96% of paired values were within clinically acceptable agreement. CGM is a reliable tool in monitoring glycemic control in the immediate postoperative period following pancreatectomy with IAT in children.

Obesity is associated with an altered HDL subspecies profile among adolescents with metabolic disease

We aimed to determine the risk factors associated with the depletion of large HDL particles and enrichment of small HDL particles observed in adolescents with T2D. Four groups of adolescents were recruited: 1) lean insulin-sensitive (L-IS), normal BMI and no insulin resistance; 2) lean insulin-resistant (L-IR), normal BMI but insulin resistance (fasting insulin levels ≥ 25 mU/ml and homeostatic model assessment of insulin resistance ≥ 6); 3) obese insulin-sensitive (O-IS), BMI ≥ 95th percentile and no insulin resistance; and 4) obese insulin-resistant (O-IR), BMI ≥ 95th percentile and insulin resistance. Plasma was separated by using gel-filtration chromatography to assess the HDL subspecies profile and compared with that of obese adolescents with T2D (O-T2D). Large HDL subspecies were significantly lower across groups from L-IS > L-IR > O-IS > O-IR > O-T2D (P < 0.0001); small HDL particles were higher from L-IS to O-T2D (P < 0.0001); and medium-sized particles did not differ across groups. The contributions of obesity, insulin resistance, and diabetes to HDL subspecies profile were between 23% and 28%, 1% and 10%, and 4% and 9%, respectively. Obesity is the major risk factor associated with the altered HDL subspecies profile previously reported in adolescents with T2D, with smaller contributions from insulin resistance and diabetes.

The incretin effect in obese adolescents with and without type 2 diabetes: impaired or intact?

The incretin effect reflects the actions of enteral stimuli to promote prandial insulin secretion. Impairment of this measure has been proposed as an early marker of β-cell dysfunction and described in T2D, IGT, and even obesity without IGT. We sought to determine the effects of obesity and diabetes on the incretin effect in young subjects with short exposures to metabolic abnormalities and a few other confounding medical conditions. Subjects with T2D (n = 10; 18.0 ± 0.4 yr) or NGT, either obese (n = 11; 17.7 ± 0.4 yr) or lean (n = 8; 26.5 ± 2.3 yr), had OGTT and iso-iv. The incretin effect was calculated as the difference in insulin secretion during these tests and was decreased ∼50% in both the NGT-Ob and T2D subjects relative to the NGT-Ln group. The T2D group had impaired glucose tolerance and insulin secretion during the OGTT, whereas the lean and obese NGT subjects had comparable glucose excursions and β-cell function. During the iso-iv test, the NGT-Ob subjects had significantly greater insulin secretion than the NGT-Ln and T2D groups. These findings demonstrate that in young subjects with early, well-controlled T2D the incretin effect is reduced, similar to what has been described in diabetic adults. The lower incretin effect calculated for the obese subjects with NGT is driven by a disproportionately greater insulin response to iv glucose and does not affect postprandial glucose regulation. These findings confirm that the incretin effect is an early marker of impaired insulin secretion in persons with abnormal glucose tolerance but suggest that in obese subjects with NGT the incretin effect calculation can be confounded by exaggerated insulin secretion to iv glucose.

Insulin Sensitivity and β-Cell Function Improve after Gastric Bypass in Severely Obese Adolescents

OBJECTIVE

To test the hypothesis that insulin secretion and insulin sensitivity would be improved in adolescents after Roux-en-Y gastric bypass (RYGB).

STUDY DESIGN

A longitudinal study of 22 adolescents and young adults without diabetes undergoing laparoscopic RYGB (mean age 17.1 ± 1.42 years; range 14.5-20.1; male/female 8/14; Non-Hispanic White/African American 17/5) was conducted. Intravenous glucose tolerance tests were done to obtain insulin sensitivity (insulin sensitivity index), insulin secretion (acute insulin response to glucose ), and the disposition index as primary outcome variables. These variables were compared over the 1 year of observation using linear mixed modeling.

RESULTS

In the 1-year following surgery, body mass index fell by 38% from a mean of 61 ± 12.3 to 39 ± 8.0 kg/m(2) (P < .01). Over the year following surgery, fasting glucose and insulin values declined by 54% and 63%, respectively. Insulin sensitivity index increased 300% (P < .01), acute insulin response to glucose decreased 56% (P < .01), leading to a nearly 2-fold increase in the disposition index (P < .01). Consistent with improved β-cell function, the proinsulin to C-peptide ratio decreased by 21% (P < .01).

CONCLUSIONS

RYGB reduced body mass index and improved both insulin sensitivity and β-cell function in severely obese teens and young adults. These findings demonstrate that RYGB is associated with marked metabolic improvements in obese young people even as significant obesity persists.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00360373.

Insulin secretion abnormalities in exocrine pancreatic sufficient cystic fibrosis patients

BACKGROUND

The aim of this study is to assess insulin secretion in pediatric cystic fibrosis (CF) patients with exocrine pancreatic sufficiency.

METHODS

Glucose and insulin responses during an oral glucose tolerance test (OGTT) were measured in 146 CF patients. Patients were divided into exocrine sufficient (CF-PS) and insufficient (CF-PI) groups based on pancreatic enzyme usage and fecal elastase. A reference group included healthy, non-diabetic subjects.

RESULTS

All CF groups showed reduced insulin secretion as measured by insulinogenic index. The CF-PS patients had normal glucose tolerance. There was a direct correlation between BMI z-score and insulin area under the curve.

CONCLUSION

Patients with CF have reduced insulin secretion during an OGTT regardless of exocrine pancreatic status. The abnormal insulin secretion in all CF patients may predispose them for glucose intolerance, particularly when challenged by inflammation, infection, or nutritional deficiency. In addition, the diminished insulin secretion may contribute to increased catabolism. Lastly, the CF-related diabetes (CFRD) screening guidelines should be followed by all CF patients regardless of pancreatic status.

Rapid deterioration of insulin secretion in obese adolescents preceding the onset of type 2 diabetes

OBJECTIVE

To identify pathophysiologic changes that lead to the onset of type 2 diabetes (T2DM) in adolescents.

STUDY DESIGN

Obese adolescents with normal glucose tolerance (n = 41) were studied longitudinally over the course of 4 years with serial measure of the acute insulin response to glucose (AIRg) as well as proinsulin (PI) concentrations. Insulin resistance was estimated with the homeostatic model assessment of insulin resistance (HOMA-IR), the disposition index (DI) computed as AIRg × 1/HOMA-IR, and intravenous glucose tolerance estimated as the glucose disappearance constant.

RESULTS

Four adolescents developed diabetes mellitus (DM) during the study, and the rest of the cohort remained nondiabetic. Baseline PI exceeded the IQR of the nondiabetic group in 3 of 4 subjects with DM, and all had >85% reduction from baseline AIRg, and DI, within 6 months of diagnosis. All the subjects with DM gained weight over the course of the study, but these changes paralleled those for the nondiabetic group. HOMA-IR increased substantially in 1 of the subjects with DM at the time of diagnosis but was comparable with baseline in the other 3. The DI and glucose disappearance constant of the subjects with DM was less than the 10th percentile of the nondiabetic group before and after diagnosis.

CONCLUSION

Conversion from normal glucose tolerance to T2DM in adolescents can occur rapidly, and the onset of T2DM is heralded by a substantial decrease in AIRg and DI, as well as increased release of PI. These results support loss of β-cell function as the proximate step in the development of T2DM in this age group.

β-cell dysfunction in adolescents and adults with newly diagnosed type 2 diabetes mellitus

OBJECTIVE

To compare β-cell function in adolescents and adults with newly diagnosed type 2 diabetes (T2DM).

STUDY DESIGN

Thirty-nine adolescents with T2DM, 38 age- and weight-matched control subjects, and 19 adults with T2DM were studied. The adolescent subjects with diabetes were divided on the basis of whether they needed insulin to control their initial hyperglycemia. The primary outcome variable was the disposition index, computed from the acute insulin response to glucose corrected for insulin sensitivity (1/Homeostatic model assessment of insulin resistance).

RESULTS

The disposition index was significantly reduced in all 3 diabetic groups (control n=3360, adolescents with T2DM without insulin n=630, adolescents with T2DM with insulin n=120, adults with T2DM n=200; P<.001), and the adolescents with more severe hyperglycemia at diagnosis had lower disposition index than those with a more modest presentation (P<.05).

CONCLUSION

At the time of diagnosis, adolescents with T2DM have significant β-cell dysfunction, comparable with adults newly diagnosed with T2DM. Thus, severe β-cell impairment can develop within the first two decades of life and is likely to play a central role in the pathogenesis of T2DM in adolescents.

Impaired beta-cell sensitivity to glucose and maximal insulin secretory capacity in adolescents with type 2 diabetes

BACKGROUND

Adults with type 2 diabetes mellitus (T2DM) have broad impairments in beta-cell function, including severe attenuation of the first-phase insulin response to glucose, and reduced beta-cell mass. In adolescents with T2DM, there is some evidence that beta-cell dysfunction may be less severe. Our objective was to determine beta-cell sensitivity to glucose and maximal insulin secretory capacity (AIR(max)) in teenagers with T2DM.

METHODS

Fifteen adolescents with T2DM [11 F/4 M, age 18.4 +/- 0.3 yr, body mass index (BMI) 39.8 +/- 2.2 kg/m(2)] and 10 non-diabetic control subjects (7 F/3 M, age 17.4 +/- 0.5 yr, BMI 41.5 +/- 2.2 kg/m(2)) were studied. T2DM subjects had a mean duration of diabetes of 48.8 +/- 6.4 months, were treated with conventional therapies, and had good metabolic control [hemoglobin A1c (HbA1c) 6.7 +/- 1.2%]. Insulin and C-peptide were determined before and after a graded glucose infusion and after intravenous arginine at a whole blood glucose level of >or=22 mM.

RESULTS

The insulin response to increasing plasma glucose concentrations was blunted in the diabetic compared with control subjects (34.8 +/- 11.9 vs. 280.5 +/- 57.8 pmol/mmol; p < 0.0001), and AIR(max) was also significantly reduced in the diabetic group (1868 +/- 330 vs. 4445 +/- 606; p = 0.0005).

CONCLUSION

Even adolescents with well-controlled T2DM have severe impairments of insulin secretion. These data support beta-cell dysfunction as central in the pathogenesis of T2DM in young people, and indicate that these abnormalities can develop over a period of just several years.

Abnormalities in glucose tolerance are common in children with fanconi anemia and associated with impaired insulin secretion

BACKGROUND

To determine prevalence of abnormal glucose metabolism in Fanconi Anemia (FA).

PROCEDURE

Thirty-nine children with FA underwent 2-hr oral glucose tolerance test (OGTT). Reference lean adolescents (REF) were older than FA patients (mean +/- SD: FA 8.6 +/- 3.9 years, REF 19.8 +/- 0.3 years, P < 0.001), but comparable in BMI Z-scores (FA 1.25 +/- 0.58, REF -0.02 +/- 0.24; P = 0.24). Patients had normal glucose tolerance (NGT) or abnormal glucose metabolism (AGM) by American Diabetes Association Criteria. Insulinogenic index estimated beta-cell function. Insulin resistance estimation used homeostatic model assessment (HOMA-IR). Insulin secretion estimation relative to insulin sensitivity used disposition index (DI).

RESULTS

Among FA patients, 46% had AGM. Compared to REF, there were significant differences in glycemic responses (area under curve: FA-NGT 344 +/- 42, FA-AGM 596 +/- 35, REF 208 +/- 25 mM, P < 0.0001) and insulinogenic index (FA-NGT 105 +/- 29, FA-AGM 44 +/- 8, and REF 173 +/- 41 pM/mM, P < 0.05). Insulin sensitivity did not differ among NGT, AGM, and REF (HOMA-IR: FA-NGT 1.9 +/- 0.4, FA-AGM 2.2 +/- 0.5, REF 1.3 +/- 0.2, P = NS). However, DI was significantly lower in both FA groups than REF [NGT 63.6 +/- 16.5 vs. AGM 26.4 +/- 3.5 (P < 0.048); REF 132.6 +/- 24.5 (NGT and AGM vs. REF, both P < 0.0002)].

CONCLUSION

Abnormalities in glucose metabolism are frequent in young FA patients without prior diagnosis of diabetes, and are associated with marked defects in insulin secretion.

Glucose tolerance, insulin secretion, and insulin sensitivity in children and adolescents with cystic fibrosis and no prior history of diabetes

OBJECTIVE

To determine the prevalence of abnormalities of glucose metabolism in pediatric outpatients with cystic fibrosis (CF).

STUDY DESIGN

Children and adolescents (n = 73, mean age 15.0 +/- 3.7 years) with CF not previously diagnosed with diabetes underwent 3-hour oral glucose tolerance testing. All subjects with CF were clinically stable and were not being treated for active infection. A reference group of young lean adults was used for comparison. Subjects were classified as having normal glucose tolerance (NGT) or abnormal glucose metabolism (AGM), including impaired glucose tolerance (IGT), impaired fasting glucose (IFG), or diabetes, by standard criteria. The insulinogenic index was calculated as a measure of beta-cell function, and insulin resistance was estimated with the homeostatic model assessment.

RESULTS

The reference group was significantly older than the patients with CF, but in the control subjects, the AGM and NGT were comparable in body mass index z-scores (-0.8 +/- 1.3, -0.6 +/- 1.1, -0.21 +/- 0.9 kg/m2). Thirty-eight percent of subjects with CF had AGM: 43% IGT, 29% IFG, 14% IGT/IFG, and 14% diabetes. In spite of distinct differences in glycemic response, the subjects with NGT and AGM had marked abnormalities of insulin secretion relative to the control subjects (Insulinogenic index 5.8 +/- 1.0, 5.3 +/- 0.8, and 53.5 +/- 10.0 uU/mL/mmol/L, respectively; P < .0001). Insulin sensitivity did not differ among the 3 groups, although there was a trend toward greater insulin resistance in the subjects with AGM (homeostatic model assessment: CF-NGT 1.5 +/- 0.2, CF-AGM 1.9 +/- 0.3, REF 1.3 +/- 0.1, P = NS).

CONCLUSION

Abnormalities in glucose metabolism are frequent in young patients with CF without a prior diagnosis of diabetes and are associated with marked defects in insulin secretion. Given the poor beta-cell function in patients with CF, even small reductions in insulin sensitivity may be an important determinant of AGM.

Beta-cell function, insulin sensitivity, and glucose tolerance in obese diabetic and nondiabetic adolescents and young adults

CONTEXT

Type 2 diabetes mellitus (T2DM) is estimated to account for 10-45% of incident pediatric diabetes cases.

OBJECTIVE

Our objective was to characterize the metabolic defects underlying T2DM in adolescents and young adults.

DESIGN, SETTING, AND PATIENTS

We conducted a cross-sectional study of islet function and insulin sensitivity in 16 adolescents with T2DM and 13 obese (OB) and 13 lean (LN) age-matched nondiabetic subjects at a University Medical Center.

INTERVENTION

We provided oral and iv glucose tolerance tests.

MAIN OUTCOME MEASURES

We measured insulin and glucagon levels, insulin sensitivity, acute insulin responses to iv glucose, and the ratio of proinsulin to immunoreactive insulin.

RESULTS

The diabetic subjects had elevated fasting insulin levels and significantly reduced insulin sensitivity (P < 0.05). The acute insulin response to iv glucose was comparable in the T2DM and LN groups (P < 0.05 for the OB vs. LN and T2DM), but insulin secretion adjusted for insulin resistance, the disposition index, was severely impaired in the diabetic subjects (P < 0.05 for the T2DM vs. LN and OB). The ratio of proinsulin to immunoreactive insulin did not differ among the three groups in the basal or stimulated state. Plasma glucagon levels were comparable before and after ingestion of glucose.

CONCLUSIONS

These findings demonstrate that diabetic adolescents have significant insulin resistance, even compared with subjects of similar obesity and body fatness, and impaired insulin secretion relative to their degree of insulin resistance. However, the adolescent diabetic subjects retained a first-phase insulin response to glucose that was comparable to lean controls and did not have hyperproinsulinemia or hyperglucagonemia.

A case of macroprolactinoma and elevated insulin-like growth factor-I in a young boy

We report a case of a 10-y-old boy who presented with persistent headache and was found to have a giant prolactinoma. Laboratory evaluation revealed markedly elevated prolactin (PRL) level, thyroid-stimulating hormone (TSH) deficiency, and elevated insulin-like growth factor-I (IGF-I). He had normal random growth hormone (GH) but non-suppressible GH during oral glucose tolerance test (OGTT). Cabergoline treatment was initiated and was well tolerated. Therapy successfully reduced PRL levels, normalized IGF-I levels, and reduced tumor size.

CONCLUSION

Our patient presented with a GH-PRL-secreting tumor. Dopamine agonists are recommended as the treatment of choice for prolactinomas. However, there should be careful attention to GH status when treating GH-PRL-secreting tumor with dopamine agonists alone. IGF-I levels should be followed in all patients with prolactinoma, even in those with normal basal GH concentrations, because of the possibility of GH co-secretion.

Kyphosis in a Turner syndrome population

OBJECTIVE

The purpose of this study was to determine the prevalence of kyphosis in a Turner syndrome (TS) population.

METHODS

Standing lateral thoracic spine and standing anterior-posterior (A-P) scoliosis radiographs were obtained on all girls with TS between the ages of 5 and 18 years seen in a TS clinic between July 2000 and March 2001. Medical histories were reviewed, and a pediatric orthopedic surgeon evaluated the radiographs of each patient (N = 25). Excessive kyphosis was defined as an A-P curvature >40 degrees, vertebral wedging as any A-P deformity >5 degrees at an individual vertebral body, and scoliosis as a lateral curvature >10 degrees.

RESULTS

Fifteen (60%) of 25 patients were found to have abnormal radiographic findings: 10 (40%) of 25 with excessive kyphosis, 10 (40%) of 25 with vertebral wedging, and 5 (20%) of 25 with scoliosis. Forty-eight percent of the girls had both excessive kyphosis and/or vertebral body wedging. Two girls had kyphosis > or =55 degrees, and 5 had scoliosis > or =25 degrees. Girls with excessive kyphosis and/or vertebral body wedging were older (13.6 +/- 3.9 years vs 10.6 +/- 2.8 years).

CONCLUSIONS

The prevalence of excessive kyphosis and vertebral body wedging seems to be increased in girls with TS and corresponds with advancing age. Routine radiologic surveillance may facilitate detection of developing deformities so that treatment with a brace can be considered to prevent or slow the process.

Type I diabetes mellitus in a patient with chromosome 22q11.2 deletion syndrome

We describe a patient with type I diabetes, clinical findings consistent with velocardiofacial syndrome, and a chromosome 22q11.2 deletion. A nine-year-old boy presented with a history of polyuria, polydipsia, weight loss, hyperglycemia, ketosis, serum insulin antibodies, and a low C-peptide level. He had distinctive facial features, learning disabilities, short stature, and a history of glottic web and clubfoot. Although a normal karyotype was obtained, fluorescence in situ hybridization (FISH) revealed a submicroscopic deletion in the DiGeorge/velocardiofacial syndrome critical region at 22q11.2. His maternal half-brother also carried a chromosome 22q11.2 deletion. His mother has similar facial features and hypoparathyroidism. Autoimmune problems associated with chromosome 22q11.2 deletions have been reported. We suggest that the defects in immune regulation due to T-cell deficiency in chromosome 22q11.2 deletion syndrome may predispose to autoimmune disorders, including type I diabetes mellitus.

Effects of hypothyroidism on insulin-like growth factor-I expression during brain development in mice

Hypothyroidism has devastating consequences on brain development. While the mechanisms that mediate these effects are not known, several lines of evidence suggest that a reduction in insulin-like growth factor-I (IGF-I) expression and/or action has a role. To assess whether reduced IGF-I expression and/or actions mediates the brain pathology of congenital hypothyroidism, we induced hypothyroidism by treating pregnant mice and lactating dams with 0. 1% propylthiouracil (PTU) in drinking water. Control and PTU-treated pups were sacrificed on postnatal day (P) 7, 10 and 14, and IGF-I mRNA expression was assessed in the cerebral cortex and cerebellum by ribonuclease protection assay. To control for mRNA loading, the signal of IGF-I protected bands was normalized to those for cyclophillin. IGF-I mRNA expression in hypothyroid animals was decreased significantly in cortex at P10 and P14 (42 and 60%, respectively). In the cerebellum, IGF-I mRNA expression was down-regulated at all ages studied, but the decrease was only statistically significant at P7 (31% decreased). We conclude that hypothyroidism alters IGF-I expression in the developing brain. Furthermore, we speculate that IGF-I plays a role in mediating some thyroid hormone actions during brain development.