A pathway to insulin independence in newborns and infants with diabetes.

Permanent neonatal diabetes was previously assumed to require insulin injection or infusion for life. Recently, permanent neonatal diabetes resulting from mutations in the two protein subunits of the adenosine triphosphate-sensitive potassium channel (Kir6.2 and SUR1) has proven to be successfully treatable with high doses of sulfonylureas rather than insulin. Many patients with these mutations first develop hyperglycemia in the nursery or intensive care unit. The awareness of the neonatolgist of this entity can have dramatic effects on the long-term care and quality of life of these patients and their families. In this study, we present the experience of our center, highlighting aspects relevant to neonatal diagnosis and treatment.

Efficacy comparison between intraportal and subcapsular islet transplants in a murine diabetic model.

BACKGROUND: It is important to determine the efficacy of intraportal (IP) islet transplantation in comparison with other transplant sites. In this study, we sought to determine the optimal number of islets to achieve normoglycemia following transplantation into the liver versus the kidney using a mouse model. METHODS: Streptozotocin-induced diabetic mice (Balb/C) were transplanted with syngeneic islets via the IP versus renal subcapsular (SC) routes. The transplanted islet numbers were 0 to 800 (n = 3-5). We assessed the correlation between parameters and islet numbers, comparing IP versus SC groups. The parameters were: (1) percentage of normoglycemia; (2) postoperative days to normoglycemia; (3) mean blood glucose levels at various points from pretransplantation to the end of the study (postoperative day 28); (4) mean serum insulin; and (5) area under the curve of blood glucose levels after glucose injection. RESULTS: Two hundred islets yielded normoglycemia in renal subcapsular grafts, while 800 islets were the minimum required for normoglycemia with IP transplantation. The transplant efficacy in SC transplantation was 2 to 5 times greater than that of IP transplantation. The days to normoglycemia were significantly different between IP versus renal SC islets (13.25 +/- 4.38 days vs 4.50 +/- 0.81 days; P = .007). CONCLUSION: The efficacy of islet transplantation in murine diabetic models was significantly greater under the kidney capsule. Clinical islet transplantation could benefit from trials of alternative transplant sites.

Dynamic production of hypoxia-inducible factor-1alpha in early transplanted islets.

More than half of transplanted beta-cells undergo apoptotic cell death triggered by nonimmunological factors within a few days after transplantation. To investigate the dynamic hypoxic responses in early transplanted islets, syngeneic islets were transplanted under the kidney capsule of balb/c mice. Hypoxia-inducible factor-1alpha (HIF-1alpha) was strongly expressed at post-transplant day (POD) 1, increased on POD 3, and gradually diminished on POD 14. Insulin secretion decreased on POD 3 in association with a significant increase of HIF-1alpha-related beta-cell death, which can be suppressed by short-term hyperbaric oxygen therapy. On POD 7, apoptosis was not further activated by continually produced HIF-1alpha. In contrast, improvement of nerve growth factor and duodenal homeobox factor-1 (PDx-1) production resulted in islet graft recovery and remodeling. In addition, significant activation of vascular endothelial growth factor in islet grafts on POD 7 correlated with development of massive newly formed microvessels, whose maturation is advanced on POD 14 with gradual diminution of HIF-1alpha. We conclude that (1) transplanted islets strongly express HIF-1alpha in association with beta-cell death and decreased insulin production until adequate revascularization is established and (2) early suppression of HIF-1alpha results in less beta-cell death thereby minimizing early graft failure.

Beneficial effects of nerve growth factor on islet transplantation.

OBJECTIVE: Development of the Edmonton protocol was a pivotal contribution to clinical islet transplantation (ITx). Persistent limitations to ITx include insufficient supply and posttransplant functional failure of islets. In this study, nerve growth factor (NGF) was used to enhance both cultured and transplanted beta-cell function, thus achieving prolonged graft survival. METHODS: Fluorescence microscopy with ethidium bromide and SYTO green staining was used to evaluate balb/c mouse islet viability. Islets were syngeneically transplanted under the kidney capsule of recipients with streptozotocin-induced diabetes. Intraperitoneal glucose tolerance was used to test posttransplant function. RESULTS: Improved viability was found in murine islets cultured for 48 hours in 500 ng/mL NGF (P < .05). A submarginal islet mass (260 islet equivalents/recipient) was used for ITx. The NGF-culture resulted in prolonged islet survival (24.7 days vs 5.5 days without NFG culture, n = 6). Intravenous injection of NGF (6 mug) on the day of transplant and postoperative days (POD) 1 + 2 prolonged islet survival from 4.1 days (no treatment) to 13.2 days (n = 6). Glucose tolerance testing performed at posttransplant day 4 showed improvement at 60 and 120 minutes in recipients treated intravenously with NGF (blood glucose of 95 +/- 15 vs 210 +/- 78 and 57 +/- 6 vs 176 +/- 70 mg/dL, respectively). CONCLUSION: NGF may improve beta-cell function and result in prolonged survival of both cultured and transplanted islets.

Islet transplant: an option for childhood diabetes?

Careful assessment of the safety and efficacy of islet transplantation should guide the selection process of a small number of children with type 1 diabetes who may be eligible for the procedure--some of whom are already receiving immunosuppression because of a previous transplant, others who are scheduled to receive de novo islet alone transplantation because of a life threatening risk of hypoglycemia. The outcomes of these initial investigations are predicted to shape the future boundaries of islet transplantation, diabetes, and transplantation.

Diabetic autoimmune markers in children and adolescents with type 2 diabetes.

BACKGROUND: There is an increase in the incidence of type 2 diabetes in children and adolescents. Absence of known diabetes autoimmune markers is sometimes required to confirm the diagnosis. OBJECTIVE: To identify clinical and autoimmune characteristics of type 2 diabetes in a pediatric population. METHOD: We report an analysis of 48 children and adolescents with type 2 diabetes, compared with 39 randomly selected children with type 1 diabetes, diagnosed and followed at the Loma Linda University Pediatric Diabetes Center. Ethnic, familial, seasonal, and autoimmune marker characteristics are outlined. To determine the reliability of antibody testing in confirming the type of diabetes at diagnosis, we studied the incidence of positive islet cell antibodies (ICAs), glutamic acid decarboxylase antibodies (GADs), and insulin autoantibodies (IAAs) at diagnosis in both groups. ICA512, GADs, and IAAs were measured by radioimmunoassay. RESULTS: The cohort with type 2 diabetes had a similar gender distribution as the group with type 1 diabetes but a significantly higher age at diagnosis. Ethnic background was significantly different between the 2 groups, predominantly Hispanic in type 2 and white in type 1. Body mass index was significantly higher in type 2 diabetes (mean = 31.24 kg/m(2)). Among the patients with type 2 diabetes, 33% presented in diabetic ketoacidosis, random blood glucose at diagnosis ranged from 11.4 to 22.25 mmol/L (228-445 mg/dL), fasting C-peptide levels ranged from 0.89 to 2.7 nmol/L (2.7-8.2 ng/mL; normal: <1.36 nmol/L), and hemoglobin A(1C) was 10.8 +/- 3.5% (normal: <6.6%). None of these parameters was significantly different from the type 1 diabetes group. Although the incidence of diabetes antibody markers was significantly lower in type 2 versus type 1 diabetes, 8.1% of patients with type 2 diabetes had positive ICAs, 30.3% had positive GADs, and 34.8% had positive IAAs without ever being treated with insulin. In the type 2 diabetes group, none of the Hispanic patients had ICAs. However, there was no significant correlation between any of the diabetes antibodies and obesity, presence of acanthosis nigricans, or family history of diabetes. The frequency of thyroid antibodies was not significantly different from the group with type 1 diabetes. Daily insulin requirements 1 year after diagnosis were significantly lower in type 2 diabetes, ranging from 0 to 1.2 U/kg with a mean of 0.33. CONCLUSION: Absence of diabetes autoimmune markers is not a prerequisite for the diagnosis of type 2 diabetes in children and adolescents.

Diabetic autoimmunity in infants and pre-schoolers with type 1 diabetes.

The incidence of type 1 diabetes is increasing most rapidly in children under 5 yrs of age, a group where the disease appears to be more accelerated than traditional type 1 diabetes. Little is known about demographics, and markers of diabetes autoimmunity, in infants and pre-schoolers with type 1 diabetes. We report an analysis of 47 children diagnosed with type 1 diabetes prior to 5 yrs of age compared with a representative cohort (n=49) diagnosed after 5 yrs of age, and all were followed at Loma Linda University (LLU) Children's Hospital. Ethnic, familial, seasonal, and autoimmune marker characteristics are outlined. To determine the prevalence of diabetes autoimmune markers, ICA512, GAD65 and insulin autoantibodies (IAA) antibodies were measured. Children with early-onset diabetes had a significantly higher incidence of viral illness symptoms (p=0.005) and diabetic ketoacidosis (DKA; p=0.017) at the time of diagnosis. However, hemoglobin A1C (HbA1c) levels at diagnosis were significantly higher in the later-onset group (p=0.001). A honeymoon period was reported in 14.8% of children diagnosed before 5 yrs of age compared with 42.1% in those diagnosed over 5 yrs of age (p=0.038). Islet-cell antibodies (ICAs) and glutamic acid decarboxylase (GAD) antibody titers were significantly different between early- and later-onset groups. ICA titers were positive in 35.29%, and GAD in 41.38% of the early-onset group versus 70.83 and 71.74% in children with later-onset disease, (p=0.001 and 0.009, respectively). IAA titers, drawn after instituting insulin therapy, were not significantly different between the two groups. GAD and ICA512 antibody results suggest a relative lack of diabetes immune markers in infants and toddlers with new-onset diabetes. This finding, and the apparent shorter pre-clinical phase reflected in the lower HbA1c values, may indicate age-related differences in type 1 diabetes autoimmunity or the existence of non-autoimmune diabetogenic mechanisms in younger children.

Changes in plasma leptin during the treatment of diabetic ketoacidosis.

To test the hypothesis that insulin regulates leptin, we measured the plasma leptin concentration before and during treatment of diabetic ketoacidosis (DKA), a condition characterized by extreme insulin deficiency. The study included 17 patients with type 1 diabetes (7 males and 10 females), aged 10+/-1 yr (mean +/- SE), with a body mass index of 17.6+/-1.9 kg/m2. Patients were treated with continuous insulin infusion and fluid and electrolyte replacement. Plasma leptin was measured every 6 h in the first 24 h, during which patients received a total insulin dose of 0.6-2.0 U/kg. Plasma leptin concentrations were also measured in a control group of 29 stable type 1 diabetic children (12 males and 17 females) and 25 healthy children (11 males and 14 females), aged 11+/-1 yr, with a body mass index of 18.5+/-1.1 kg/m2. Before treatment, plasma leptin concentrations were significantly lower in patients with DKA than those in diabetic and healthy controls (4.9+/-1.2 vs. 9.0+/-1.8 and 11.2+/-2.1 ng/mL, respectively; P < 0.05). In the DKA patients, plasma leptin increased to 6.4+/-1.5, 7.5+/-1.9, 9.1+/-2.7, and 8.9+/-2.5 at 6, 12, 18, and 24 h, respectively, after starting treatment (P = 0.001). Thus, leptin levels increased by 38+/-10% and 92+/-38% within 6 and 24 h of starting treatment. There was no difference in the change in plasma leptin by 24 h between subjects who could eat (n = 7) and those who could not (n = 10). The plasma leptin increase was paralleled by a rise in insulin level and a decline in glucose and cortisol levels at 6 and 24 h. In conclusion, DKA was associated with decreased plasma leptin concentrations. Treatment resulted in a significant increase in plasma leptin, which may be due to the effect of insulin on leptin production. Our data lend support to the hypothesis that insulin is the link between caloric intake and plasma leptin.

Normal growth despite GH, IGF-I and IGF-II deficiency.

A 6.5-year-old male with normal linear growth, despite septo-optic dysplasia, panhypopituitarism and a deficient GH/IGF axis, is presented. In addition to measuring IGF-I, IGF-II and IGFBP-3, serum IGFBP-1, -2, -4 and -5 were measured. A human osteosarcoma cell line was used to assess growth-promoting activity in the patient's serum. The role of leptin in linear growth in this case was investigated. There was no evidence for hyperinsulinism or hyperandrogenism. GH was undetectable upon multiple stimulation. GHBP was elevated. Serum IGF-I (25 microg/l), IGF-II (194 microg/l), IGFBP-3 (0.4 mg/l), and IGFBP-5 (87 microg/l) levels were low compared to age-matched prepubertal children. Serum IGFBP-4 level was normal. Molecular size of IGF-II in the patient's serum was normal, suggesting normal IGF-II bioavailability. Human osteosarcoma cell proliferation in response to the patient's serum was similar to sera from age-matched normal controls. Leptin levels were markedly elevated. Osteoblast cell proliferation was not stimulated by leptin. The data demonstrate that normal growth and osteoblast cell proliferation in this patient is not mediated by GH, total IGFs, insulin, or leptin, and suggest the presence of a yet unidentified growth factor or mechanism. The case offers a detailed picture of binding proteins in a case of growth without GH. It introduces osteoblast cell proliferation as a method of assessing serum growth-promoting activity in such cases. It adds IGF-II and leptin to the list of excluded growth-promoting candidates in GH-independent growth, and further demonstrates our incomplete understanding of the phenomenon of growth.

Association of terminal chromosome 1 deletion with sertoli cell-only syndrome.

We report on del(1)(q44), developmental delay, cryptorchidism, and seizure disorder in a 19-year-old man. Endocrinologic evaluation showed delayed puberty and elevated gonadotropins. Testicular biopsy was consistent with Sertoli cell-only syndrome. The case illustrates a previously an unreported manifestation in males with del(1)(q44), and suggests a link between the development of germinal epithelium and genes in the 1q44 area.

Hemifacial microsomia and abnormal chromosome 22.

We report on partial dup(22q), growth deficiency, and the facioauriculovertebral sequence including hemifacial microsomia, cleft lip and palate, preauricular tags, and hearing loss in one patient. No endocrine or systemic cause for growth deficiency was identified. The case illustrates applicability of chromosome analysis in syndrome-associated growth failure, and a previously unreported associated chromosome abnormality.