Risk of recurrent severe hypoglycemia remains associated with a past history of severe hypoglycemia up to 4 years: Results from a large prospective contemporary pediatric cohort of the DPV initiative

OBJECTIVES

In a contemporary cohort of youth with type 1 diabetes, we examined the interval between episodes of severe hypoglycemia (SH) as a risk factor for recurrent SH or hypoglycemic coma (HC).

METHODS

This was a large longitudinal observational study. Using the DPV Diabetes Prospective follow-up data, we analyzed frequency and timing of recurrent SH (defined as requiring assistance from another person) and HC (loss of consciousness or seizures) in 14 177 youths with type 1 diabetes aged <20 years and at least 5 years of follow-up.

RESULTS

Among 14 177 patients with type 1 diabetes, 72% (90%) had no, 14% (6.8%) had 1 and 14% (3.2%) >1 SH (HC). SH or HC in the last year of observation was highest with SH in the previous year (odds ratio [OR] 4.7 [CI 4.0-5.5]/4.6 [CI 3.6-6.0]), but remained elevated even 4 years after an episode (OR 2.0 [CI 1.6-2.7]/2.2 [CI 1.5-3.1]). The proportion of patients who experienced SH or HC during the last year of observation was highest with SH/HC recorded during the previous year (23% for SH and 13% for HC) and lowest in those with no event (4.6% for SH and 2% for HC) in the initial 4 years of observation.

CONCLUSIONS

Even 4 years after an episode of SH/HC, risk for SH/HC remains higher compared to children who never experienced SH/HC. Clinicians should continue to regularly track hypoglycemia history at every visit, adjust diabetes education and therapy in order to avoid recurrences.

Treatment of young patients with HNF1A mutations (HNF1A-MODY)

AIM

Children and adolescents with a molecular diagnosis of HNF1A-MODY should be treated with oral sulfonylurea according to current International Society for Pediatric and Adolescent Diabetes (ISPAD) guidelines.

METHODS

We surveyed the German-Austrian DPV database of 50 043 people and included 114 patients with a confirmed molecular-genetic diagnosis of HNF1A mutation and diabetes onset at below age 18 years. We analysed hypoglycaemic episodes, metabolic control (HbA1c ) and other clinical variables according to treatment groups.

RESULTS

People with HNF1A-MODY were included and analysed according to treatment with insulin alone (n = 34), sulfonylurea (n = 30), meglitinides (n = 22) or lifestyle (n = 28). In those receiving any drug treatment (n = 86), severe hypoglycaemia did not occur with meglitinide and was highest (at 3.6 events per 100 patient-years) with insulin. HbA1c was highest with insulin treatment (insulin = 58 mmol/mol, 7.5%; sulfonylurea = 55 mmol/mol, 7.2%; meglitinides = 52 mmol/mol, 6.9%; P = 0.008), whereas weight (BMI SD score), serum lipids and blood pressure were not different.

CONCLUSIONS

Of note, 40% of people with HNF1A-MODY and medical treatment were receiving insulin alone and thus were not being treated in line with up-to-date International Society for Pediatric and Adolescent Diabetes/International Diabetes Federation guidelines, despite insulin treatment being associated with worse metabolic control and the risk of hypoglycaemia. The unlicensed use of oral drugs in patients below age 18 years and adherence by both doctors and patients to the initial insulin treatment might contribute to this finding.

Diabetic retinopathy in type 1 diabetes-a contemporary analysis of 8,784 patients

AIMS/HYPOTHESIS

The aim of this study was to analyse the risk profile for diabetic retinopathy under real-life conditions in a large cohort of patients with type 1 diabetes.

METHODS

Patients (n = 18,891) with childhood, adolescent or adult onset of type 1 diabetes from the prospective German Diabetes Documentation System survey were analysed. A total of 8,784 patients fulfilled the inclusion criterion, which was availability of retinopathy status. Retinopathy grading (any retinopathy, advanced retinopathy), treatment regimens and risk factors were prospectively recorded and tested as covariates by Kaplan-Meier analysis and logistic regression.

RESULTS

Any retinopathy was present in 27.4% and advanced retinopathy (severe non-proliferative or proliferative diabetic retinopathy) in 8.0% of the cohort. After 40 years of diabetes, the cumulative proportion of patients with any retinopathy and advanced retinopathy was 84.1% and 50.2%, respectively. In multiple regression analysis, risk factors for any retinopathy were diabetes duration (OR 1.167 per year), HbA(1c) >7.0% (53 mmol/mol) (OR 2.225), smoking (OR 1.295) and male sex (OR 1.187) (p < 0.0001 for all). Young age at onset (5 vs 15 years at disease onset) was protective (0.410, p < 0.0001). No glycaemic threshold was detected for retinopathy protection. Risk factors for advanced retinopathy were duration (1.124 per year, p < 0.0001), male sex (1.323, p = 0.0020), HbA(1c) >7.0% (53 mmol/mol) (1.499, p < 0.0001), triacylglycerol >1.7 mmol/l (1.398, p = 0.0013) and blood pressure  >140/90 mmHg (1.911, p < 0.0001).

CONCLUSIONS/INTERPRETATION

The prevalence of retinopathy remains significant in type 1 diabetes. Any improvement of metabolic control and non-smoking is protective, while hypertension affects progression to severe levels under real-life conditions. These data reinforce the validity of multifactorial concepts for morbidity protection in type 1 diabetes.

Genetic and clinical characteristics of patients with HNF1A gene variations from the German-Austrian DPV database

OBJECTIVE

To determine prevalence, genetic and phenotype characteristics of patients with hepatocyte nuclear factor-1α (HNF1A) variants in the Diabetes Patienten Verlaufsdokumenation (DPV) multicentre database and to examine the influence of HNF1A mutation type, or location on clinical phenotypes.

PATIENTS AND METHODS

Seventy-one DPV patients were labelled as HNF1A-MODY (MODY3). Forty-four patients carried HNF1A mutations, while 27 patients were found to have HNF1A polymorphisms only. Associations between mutation type/position and age at disease onset, HbAlc, body mass index (BMI), diagnosis, family history and treatment modality were analysed using non-parametric statistics (Wilcoxon test).

RESULTS

Patients with HNF1A mutations were 36% male, aged 14.1±5.8 years at diagnosis, and slightly overweight (BMI-SDS: +0.8±1.1). Treatment was lifestyle intervention (20.5%), insulin (35.3%), oral anti-diabetic (OAD, 43%) and both insulin+OAD (15.9%). More patients with missense mutations (60%) than patients with nonsense mutations/frameshift (23.8%) did not use insulin (P=0.03). No differences were found with regard to mutation types, isoform or domain. We identified several previously undescribed mutations in the cohort including c.-158insGGGTTGG in the promoter region, G31X, E41X, Q130X, L162P, R245I, A269P, S355X, Q398X, Q473X, Q495X, E508X, P588fs-insGCCA and P588fs-delAC. Patients carrying HNF1A polymorphisms were significantly younger at diagnosis than patients with HNF1A mutations (10.9±4.2 vs 14.19±5.8 years; P=0.027), and all carried I27L, S487N and A98V (n=3).

CONCLUSION

HNF1A-MODY is the second most frequent MODY diagnosis registered in the DPV database, and previously undescribed HNF1A mutations account for about one-third of HNF1A-MODY cases. Patients with HNF1A polymorphisms documented as HNF1A-MODY were misclassified. They may have autoantibody-negative type 1B or type 2 diabetes or may have other MODY types.

Entities and frequency of neonatal diabetes: data from the diabetes documentation and quality management system (DPV)

AIMS

The aim of this study was to elucidate the entities and the frequency of neonatal diabetes mellitus (NDM) in a large representative database for paediatric diabetes patients in Germany and Austria.

METHODS

Based on the continuous diabetes data acquisition system for prospective surveillance (DPV), which includes 51,587 patients with onset of diabetes before the age of 18 years from 299 centres in Germany and Austria, we searched for patients with onset of diabetes mellitus in the first 6 months of life.

RESULTS

Ninety patients were identified, comprising 0.17% of all paediatric cases in the DPV registry. This represented an incidence of approximately one case in 89,000 live births in Germany. A monogenic basis for NDM was established in 30 subjects (seven UPD6, 10 KCNJ11, seven ABCC8, two FOXP3, two PDX1, one INS, one EIF2AK3). Pancreatic hypoplasia or agenesis was reported in 10 patients and seven subjects were classified as having Type 1 diabetes by their centres. Transient neonatal diabetes (TNDM) accounted for approximately 10% of all cases with NDM. No aetiology was defined in 41 subjects, which may reflect incomplete genetic testing or novel genetic aetiologies.

CONCLUSION

Based on a large database, we identified a higher rate of NDM in Germany than has been reported previously. Full molecular genetic testing should be performed in all patients diagnosed before 6 months of age.

Discontinuation of insulin pump treatment in children, adolescents, and young adults. A multicenter analysis based on the DPV database in Germany and Austria

BACKGROUND

Insulin pump therapy is well established in the treatment of children and adolescents with type 1 diabetes. Most studies focus on outcome parameters like hemoglobin A1c (HbA1c), hypoglycemia, and quality of life, whereas few reports address patients who discontinue pump therapy.

OBJECTIVE

This survey focuses on the discontinuation rate of insulin pump treatment in the pediatric and young adult age group.

SUBJECTS AND METHODS

The prospective multicenter Diabetes Patienten Verlausdokumentation (DPV) (electronic diabetes patient documentation system) database has been established since 1990 and is broadly used in Germany and Austria. All pump users among the participating centers documented since 1995 were included in this analysis.

RESULTS

In total, 11 710 patients with type 1 diabetes were recorded as treated with insulin pumps. In total, 463 patients (4%) switched from insulin pump treatment to multiple daily injections (MDI). In the group of patients who stopped with pump treatment, the mean duration of pump therapy was 1.7 yr (SE +/- 0.06 yr), 60.5% of patients were female. Subdivided into age groups, the discontinuation rate was lowest in the age group < 5 yr (0.1%), followed by the groups aged 5-10 yr (0.3%) and 15-20 yr (0.8%). The group aged 10-15 yr showed the highest rate of discontinuation (2%).

CONCLUSIONS

The discontinuation rate of insulin pump therapy is, in general, low (4%). The younger the patients at the time of initiating insulin pump treatment, the lower is the discontinuation rate. The highest rate was seen in adolescents aged 10-15 yr. Girls stopped insulin pump treatment more often than boys (60.5% vs. 39.5%).

Insulin allergy: clinical manifestations and management strategies

Insulin allergy in patients with diabetes mellitus on insulin treatment is a rare condition. It is suspected upon noticing immediate symptoms following insulin injections. The immediate vital implications for the patient call for prompt diagnosis and management of insulin allergy. We review current knowledge and procedures based on four diabetic patients who presented in our clinic. Insulin allergy was suspected as they showed immediate symptoms after insulin injection (urticaria, rash, angioedema, hypotension, dyspnea). A detailed allergologic work-up was performed and adequate therapy was initiated. In three of the four patients, a specific immunotherapy was started whereas in one patient a switch to oral antidiabetics was possible and consequently initiated. By standard prick testing and measurement of specific IgE antibodies, a type 1 IgE-mediated allergy was confirmed. After initiation of insulin immunotherapy, the symptoms completely resolved in two out three of patients and significantly improved in the third patient. The fourth patient was successfully switched to oral antidiabetics. Insulin allergy is a rare but severe condition that calls for immediate allergological work-up. It can be managed well in close cooperation between the diabetologist and the allergologist. Specific immunotherapy is efficient and should be considered.

Metabolic decompensation in children with type 1 diabetes mellitus associated with increased serum levels of the soluble leptin receptor

OBJECTIVE

Type 1 diabetes mellitus (T1DM) leads to increased serum levels of the soluble leptin receptor (sOB-R) by an as yet unknown cellular mechanism. The aim of our study was to investigate potential metabolic factors that may be associated with the induction of the sOB-R release from its membrane receptor.

MATERIALS AND METHODS

Twenty-five children (aged between 1.5 and 17.0 years) were studied at the onset of T1DM. Blood samples were collected before (n = 25), during the first 18 h (mean +/- S.D. 11.1 +/- 4.3 h, n = 16) and 92 h (47.5 +/- 22.5 h; n = 14) after beginning insulin therapy. Serum sOB-R and leptin levels were determined by in-house immunoassays.

RESULTS

The sOBR-level and the molar sOB-R/leptin ratio were significantly higher before than after starting insulin treatment (P < 0.05). In contrast, leptin levels were significantly lower (P < 0.05) before insulin therapy. The correlation between sOB-R and blood glucose (r = 0.49; P < 0.05), as well as sOB-R with parameters of ketoacidosis, such as pH (r = -0.72), base excess (r = -0.70), and bicarbonate (r = -0.69) (P < 0.0001) at diagnosis of T1DM remained significant during the first 18 h of insulin treatment. Multiple regression analysis revealed that base excess predicted 41.0% (P < 0.001), age 16.4% (P < 0.05), and height SDS 13.9% (P < 0.01) of the sOB-R variance.

CONCLUSIONS

Metabolic decompensation in children with new onset T1DM is associated with dramatic changes of the leptin axis; serum levels of sOB-R are elevated and of leptin are reduced. The molar excess of sOB-R over leptin (median 11.3) in this condition may contribute to leptin insensitivity. Upregulation of the soluble leptin receptor appears to be a basic mechanism to compensate for intracellular substrate deficiency and energy-deprivation state.

Mutational spectrum of COH1 and clinical heterogeneity in Cohen syndrome

Cohen syndrome (CS) is an autosomal recessive disorder with variability in the clinical manifestations, characterised by mental retardation, postnatal microcephaly, facial dysmorphism, pigmentary retinopathy, myopia, and intermittent neutropenia. Mutations in the gene COH1 have been found in an ethnically diverse series of patients. Brief clinical descriptions of 24 patients with CS are provided. The patients were from 16 families of different ethnic backgrounds and between 2.5 and 60 years of age at assessment. DNA samples from all patients were analysed for mutations in COH1 by direct sequencing. Splice site mutations were characterised using reverse transcriptase PCR analysis from total RNA samples. In this series, we detected 25 different COH1 mutations; 19 of these were novel, including 9 nonsense mutations, 8 frameshift mutations, 4 verified splice site mutations, 3 larger in frame deletions, and 1 missense mutation. We observed marked variability of developmental and growth parameters. The typical facial gestalt was seen in 23/24 patients. Early onset progressive myopia was present in all the patients older than 5 years. Widespread pigmentary retinopathy was found in 12/14 patients assessed over 5 years of age. We present evidence for extended allelic heterogeneity of CS, with the vast majority of mutations leading to premature termination codons in COH1. Our data confirm the broad clinical spectrum of CS with some patients lacking even the characteristic facial gestalt and pigmentary retinopathy at school age.

Clinical and functional characteristics of the human Arg59Ter insulin-like growth factor i receptor (IGF1R) mutation: implications for a gene dosage effect of the human IGF1R

CONTEXT

Signaling via the IGF-I receptor (IGF-IR) is crucial for normal prenatal and postnatal growth. The heterozygous IGF-IR mutation Arg59Ter resulted in reduced IGF-IR expression and represents haploinsufficiency of the human IGF1R gene.

OBJECTIVE

We studied clinical and in vitro aspects of a human IGF1R gene dosage effect. We provide detailed clinical data on the two half-brothers and their mother with the Arg59Ter mutation. Arg59Ter and control fibroblasts were examined for functionality of IGF-I and insulin-stimulated receptor phosphorylation and signal transduction.

RESULTS

The two brothers presented with primary microcephaly, mild mental retardation, and intrauterine as well as postnatal growth deficits. After GH therapy (30 microg/kg.d) for 24 months, the growth deficit in the propositus decreased by +1.0 sd. There was no clinical evidence for impaired glucose tolerance or hypoglycemia in all Arg59Ter subjects. In vitro, IGF-IR-deficient Arg59Ter cells expressed less IGF-IR and unchanged insulin receptor (IR) protein. Receptor autophosphorylation and phosphorylation of downstream protein kinase B/Akt exhibited resistance to IGF-I but showed an augmented response to insulin in Arg59Ter cells. Decreased IGF-IR content was accompanied by a reduction of IGF-IR/IR receptor hybrids, and therefore, increased levels of IR/IR homodimers probably explain increased insulin-stimulated receptor autophosphorylation and Akt phosphorylation.

CONCLUSIONS

In vivo and in vitro IGF-I resistance in Arg59Ter subjects and fibroblasts indicates a human IGF1R gene dosage effect involving not only the IGF-IR, but also IGF-IR/IR hybrids. The abundance of both the IGF-IR protein and IGF-IR/IR hybrid receptors may have an impact on human growth, organ function, and glucose metabolism.

Glucose regulates expression of the nerve growth factor (NGF) receptors TrkA and p75NTR in rat islets and INS-1E beta-cells

BACKGROUND

The function and survival of pancreatic beta-cells strongly depend on glucose concentration and on autocrine secretion of peptide growth factors. NGF and its specific receptors TrkA and p75NTR play a pivotal role in islet survival and glucose-dependent insulin secretion. We therefore investigated whether or not glucose concentration influences expression of TrkA and p75NTR in rat islets and in INS-1E beta-cells at the mRNA and protein level (INS-1E).

METHODS

Gene expression of the NGF receptors TrkA and p75NTR but also of the metabolic gene liver-type pyruvate kinase (L-PK) and the neurotrophin receptors TrkB and TrkC was studied by semi-quantitative PCR and by real-time PCR in islets and INS-1E beta-cells.

RESULTS

In rat islets, high glucose exposure (25 mmol/l) increased gene expression of TrkA, p75NTR and L-PK. Expression of TrkA, p75NTR and L-PK reflected insulin secretion at the respective glucose concentration. In rat INS-1E insulinoma cells, expression of L-PK and p75NTR was suppressed by low glucose as in the islets, while expression of TrkA was strongly increased by low glucose levels and thus was regulated differently than in islets. Expression of TrkB and TrkC was not regulated by glucose concentration at all. TrkA protein was regulated in the same fashion as its mRNA expression, while p75NTR protein was not significantly regulated within 24 h.

CONCLUSION

Glucose interacts with gene expression of TrkA and p75NTR that are strongly involved in beta-cell growth and glucose-dependent insulin secretion. The fact that TrkA expression is regulated the opposite way in islets and in INS-1E beta-cells might reflect their specific grade of differentiation and tendency to proliferate.

Glucose concentration and AMP-dependent kinase activation regulate expression of insulin receptor family members in rat islets and INS-1E beta cells

AIMS/HYPOTHESIS

Glucose and the peptide growth factors insulin, IGF-I and IGF-II strongly regulate beta cell mass. Furthermore, beta cell expression of IGF-I receptor (Igf1r) and insulin receptor (Insr) is mandatory for several steps of insulin secretion.

MATERIALS AND METHODS

We hypothesised that glucose concentration might regulate expression of Igf1r, Insr and insulin receptor-related receptor (Insrr) in islets and beta cells. Moreover, since the ratio of ATP:ADP is the most important intracellular mechanism involved in insulin secretion, and since depletion of ATP leads to AMP accumulation, we evaluated the role of AMP-activated protein kinase (AMPK) in glucose-dependent receptor regulation.

RESULTS

In rat islets, high glucose exposure (25 mmol/l) increased gene expression of Igf1r, Insr and Insrr but also of the metabolic glycolysis gene liver-type pyruvate kinase (Pklr) compared with intermediate (6.2 mmol/l) or low glucose concentration (1.6 mmol/l) after 24 h. In rat INS-1E beta cells, only Pklr expression was suppressed by low glucose as in islets, while Insr and Insrr were suppressed by high and increased by low glucose levels. Igf1r expression was suppressed by both high- and low- glucose concentration. Activation of AMPK by 5-amino-imidazolecarboxamide riboside (AICAR, 0.5 mmol/l) suppressed Pklr expression, but strongly stimulated gene expression of Igf1r, Insr and Insrr. Protein expression of IR and IGF-IR reflected glucose and AICAR-regulated mRNA expression of both receptors in INS-1E cells.

CONCLUSIONS/INTERPRETATION

We conclude that glucose directly interacts with islet and beta cell expression of growth factor receptors that are mandatory for both beta cell growth and insulin secretion. Stimulation of Igf1r and Insr gene expression by the AMPK-activator AICAR might indicate involvement of AMPK in the regulation of Igf1r, Insr and Insrr expression in beta cells.

A new heterozygous mutation of the FOXL2 gene is associated with a large ovarian cyst and ovarian dysfunction in an adolescent girl with blepharophimosis/ptosis/epicanthus inversus syndrome

Blepharophimosis/ptosis/epicanthus inversus syndrome (BPES), an autosomal dominant syndrome in which eyelid malformation is associated with (type I BPES) or without premature ovarian failure (type II BPES). Mutations of a putative winged helix/forkhead transcription factor FOXL2 account for both types of BPES. We report on a 16-year-old adolescent girl with blepharophimosis and ptosis. Subsequently she developed oligomenorrhea, secondary amenorrhea for 6 months, and an extremely large cyst of one ovary. The cyst contained 8 l of cyst fluid and histopathology displayed a large corpus luteum cyst. Following laparotomy, gonadotropin levels were elevated (LH 17.2 U/l, FSH 29.4 U/l) and estradiol levels decreased (67 pmol/l). Because of clinical aspects of BPES and abnormal ovarian function we suspected a mutation of her FOXL2 gene and found a new in-frame mutation (904_939dup36) on one allele, leading to a 12 alanine expansion within the polyalanine domain. We conclude that the FOXL2 mutation 904_939dup36 may account not only for blepharophimosis and ptosis but also for ovarian dysfunction and growth of the large corpus luteum cyst. In contrast to known FOXL2 mutations with polyalanine expansions and association with BPES type II, clinical aspects of our girl may indicate some degree of ovarian dysfunction that might finally lead to BPES type I with premature ovarian failure.

[Treatment of adolescents with type 2 diabetes]

BACKGROUND

A worldwide increased incidence of adolescents with type 2 diabetes mellitus is evident. Only few substances are available for treatment of adolescents with type 2 diabetes. We report on our experience of treatment in the diabetes centre in Leipzig, Germany.

PATIENTS AND METHODS

At the moment we care for three patients with type 2 diabetes (two girls and one boy) age 16 - 17 years. We retrospectively analyzed the patients records for symptoms at onset, BMI, HbA1c and treatment for a maximum of 4 years.

RESULTS

None of the adolescents had typical symptoms at onset. All had first or second degree relatives with type 2 diabetes. Diagnosis was made using oral glucose tolerance test. BMI at onset was 26 kg/m (2) (90.-97 percent) to 35.2 kg/m (2) (>99.5 percent). Fasting and stimulated insulin and c-peptide levels were elevated in all cases. An elevated HbA1c level was found in one patient. Two patients had further metabolic symptoms like hypertriglyceridemia or hyperurikemia. We started with metformin after dietary instructions in all cases. One girl is on insulin at the moment and the boy stopped metformin after weight reduction of 24.5 kg.

CONCLUSIONS

In Germany type 2 diabetes is diagnosed more frequently at an early age. Adolescents with type 2 diabetes should be treated in a centre for pediatric diabetology. Treatment should consist of an individualized care for all aspects of type 2 diabetes.

Type 2 diabetes mellitus in children and adolescents: a review from a European perspective

Changes in food consumption and exercise are fueling a worldwide increase in obesity in children and adolescents. As a consequence of this dramatic development, an increasing rate of type 2 diabetes mellitus has been recorded in children and adolescents in the USA and, more recently, in many countries around the world. Both genetic and environmental factors contribute to the pathogenesis of type 2 diabetes. Lower susceptibility in white Caucasians and higher susceptibility in Asians, Hispanics and blacks have been noted. There is a high hidden prevalence and a lack of exact data on the epidemiology of the disease in Europe: in Germany only 70 patients below the age of 15 years were identified in the systematic, nationwide DPV (Diabetessoftware für prospektive Verlaufsdokumentation) diabetes survey, but our calculations suggest that more than 5000 young people in Germany at present would meet the diagnostic criteria of type 2 diabetes. In Australasia, the prevalence of type 2 diabetes is reportedly high in some ethnic groups and again is linked very closely to the obesity epidemic. No uniform and evidence-based treatment strategy is available: many groups use metformin, exercise programmes and nutritional education as a comprehensive approach to treat type 2 diabetes in childhood and adolescence. The lack of clear epidemiological data and a strong need for accepted treatment strategies point to the key role of preventive programmes. Prevention of obesity will help to counteract the emerging worldwide epidemic of type 2 diabetes in youth. Preventive programmes should focus on exercise training and reducing sedentary behaviour such as television viewing, encouraging healthy nutrition and supporting general education programmes since shorter school education is clearly associated with higher rates of obesity and hence the susceptibility of an individual to acquire type 2 diabetes.

Insulin-like growth factor I (IGF-I) stimulates proliferation but also increases caspase-3 activity, Annexin-V binding, and DNA-fragmentation in human MG63 osteosarcoma cells: co-activation of pro- and anti-apoptotic pathways by IGF-I

Insulin-like growth factor-I (IGF-I) was found to promote proliferation, cell survival, and inhibition of apoptosis. But in some instances, IGF-I was found to mildly induce apoptosis, i. e. Fas-mediated apoptosis in human MG63 osteosarcoma cells. In the present study, we intended to further investigate IGF-I dependent pathways leading either to proliferation and cell survival or to cell death. MG63 osteosarcoma cells were treated with serum free medium alone or in combination with IGF-I, a neutralizing antibody against the human IGF-I receptor (alphaIR-3) or non-immune control IgG (1) for two to six days. We investigated cell survival (cell count), proliferation (CD71-FACS), apoptosis (Annexin-V-FACS, Caspase-3 activity, PCD) and anti-apoptosis (112-Ser Bad phosphorylation), and regulation of IGF-I receptor surface expression (IGF-I receptor-FACS). We found that IGF-I treatment (48 h) stimulated cell growth and proliferation, but also mildly induced apoptosis. IGF-I activated specific apoptotic pathways (Caspase-3 activation, Annexin-V binding and DNA degradation), as well as anti-apoptotic signals (Bad phosphorylation at serine 112). alphaIR-3 blocked cell proliferation, strongly induced apoptosis, and inhibited Bad-phosphorylation. Thus, IGF-I treatment overall resulted in increased tumour cell mass, despite a detectable stimulation of apoptosis; in other words proliferation exceeded cell death. If IGF-I was first added on day 0, 2, or 4 of serum free culture, we found decreasing IGF-I specific effects on proliferation and apoptosis. In parallel, we found a down-regulation of IGF-I receptors (FACS) by serum withdrawal, which was partly reversed if IGF-I was added. Therefore receptor number might have an impact on IGF-I function in MG63 cells. In conclusion, co-activation of apoptosis and proliferation by IGF-I might result in higher cell turnover in MG63 osteosarcoma cells. Furthermore, in sarcomas or carcinomas showing clinical association to IGF-I levels and malignancy, IGF-I dependent apoptosis and proliferation could be a significant mechanism of malignant tumour growth.

IGFs, basic FGF, and glucose modulate proliferation and apoptosis induced by IFNgamma but not by IL-1beta in rat INS-1E beta-cells

We investigated the effects of glucose and beta-cell growth factors (IGF-I, IGF-II, bFGF) on growth and apoptosis in the presence and absence of apoptosis inducing cytokines (IFNgamma, Il-1beta, TNFalpha). Rat INS-1E beta-cell viability was measured by WST-1 viability assay and cell counting, apoptosis by FACS analysis of annexin-V-FITC and fluorescein-dUTP (TUNEL-staining)-positive cells. Glucose alone maintained INS-1E beta-cell viability at high physiological concentrations (6.2-12.5 mmol/l), addition of IGF-II alone or in combination with bFGF further increased these glucose effects. The cytokines IFNg and IL-1beta, but not TNFalpha strongly induced INS-1E beta-cell apoptosis. Interestingly, glucose alone induced apoptosis at extremely low or very high concentrations. In combination with IFNg, low glucose (1.6 mmol/l) increased apoptosis by 25.6% (1SD 5.0%) and high glucose (50 mmol/l) by 22.8% (1SD 2.8%) compared to 12.5 mmol/l glucose. In contrast, glucose failed to modulate IL-1beta-induced apoptosis. Most importantly, IGF-II and bFGF inhibited apoptosis induced by IFNg, but not by IL-1beta. Therefore, IGF signaling, supported by bFGF and optimal glucose levels, maintains beta-cell viability in vitro. Cytokines IFNg and IL-1beta differentially interfere with intracellular signaling cascades stimulated by IGFs and bFGF or glucose, respectively.

Weight in adolescents with type 1 diabetes mellitus during continuous subcutaneous insulin infusion (CSII) therapy

Continuous subcutaneous insulin infusion (CSII) has become increasingly popular as a form of intensified insulin therapy in adolescents with type 1 diabetes mellitus (DM). One reported drawback was increased weight gain in adolescents after initiation of insulin pump therapy. In a prospective, longitudinal, non-randomized and case controlled study, we followed 12 adolescents (mean age 13.6 yr, 8 males, 4 females) from 6 months before the start of CSII to 12 months on CSII. These 12 adolescents with DM on CSII were matched for age, gender, HbA1c, duration of DM, and body mass index (BMI) with 12 adolescents who continued on multiple injection therapy (MIT). In addition, six of the 12 adolescents on CSII intended to control their weight by means of the insulin pump. These six vs six adolescents within the CSII group were further analyzed for weight development and eating habits. Clinical indications for CSII were dawn phenomenon, night-time hypoglycemia and patient request for more flexibility in DM management. All patients had been in satisfactory metabolic control on MIT. After 12 months of CSII, the daily insulin requirement remained significantly lower than 18 months before (0.79 +/- 0.11 vs 1.02 +/- 27 U/kg/d, p = 0.034) and number of daily meals was lower (4.1 +/- 0.9 vs 6.5 +/- 0.7, p = 0.006). Mean initial HbA1c was 7.4% in the MIT and CSII patients, and remained comparable between these two groups. BMI was not different between the CSII and MIT group over the entire study period. However, those adolescents on CSII who intended to control their weight by means of the insulin pump were able to achieve relative weight loss during the,first 6 months on CSII. Two patients of the CSII group had one severe hypoglycemic episode with loss of consciousness. In conclusion, CSII does not lead to weight gain by itself, but allows sufficient weight control without a negative effect on metabolic control. The general threat of weight gain in patients who switch to insulin pump therapy must be pointed out, and the role of eating habits and caloric content of food should play a central role in insulin pump educational programs.

Insulin antibodies are associated with lipoatrophy but also with lipohypertrophy in children and adolescents with type 1 diabetes

AIM

To evaluate clinical and immunological factors that are associated with lipodystrophy, i.e. lipoatrophy and lipohypertrophy, in diabetic children and adolescents.

METHODS

We investigated in a cross-sectional study 112 children and adolescents (age 1.1-19.1 yrs.) with type 1 diabetes. To grade lipodystrophy, we developed a clinical score ranging from normal (grade 0), moderate hypertrophy of subcutaneous tissue (grade 1), severe hypertrophy with increased density of tissue (grade 2) to lipoatrophy (grade 3). In all children, grade of lipodystrophy, antibodies against insulin (IA) or beta cell antigens (IA-2 and GAD) and clinical parameters were documented.

RESULTS

The antibodies against insulin (IA) increased significantly after diabetes manifestation and initiation of insulin treatment, while beta cell specific antibodies (IA-2, GAD) did not. Lipoatrophy (grade 3) was seen in 4 children, severe lipohypertrophy (grade 2) in 18 and moderate lipohypertrophy (grade 1) in 27 children. No alteration of injection sites was found in 63 children. Amongst clinical and immunological parameters, IA levels were significantly associated with hypertrophy or atrophy of injection sites.

CONCLUSION

The strong association of lipoatrophy and lipohypertrophy with insulin antibodies might suggest that autoimmune phenomena with insulin play a role in the development of both. Despite an association of IA and lipodystrophy in type 1 diabetic children, the causal link between the two remains unproven and requires further longitudinal exploration.

Apoptosis: live or die--hard work either way!

This review presents a brief overview of the cell's apoptotic machinery, including specific and indirect death signals. Specific death signals are transferred via death ligands, death receptors, and their intracellular signalling pathways. Indirect death signals cumulate a wide range of stimuli that potentially harm survival of cells. These include intercalating drugs, irradiation or altered intracellular signalling. Herein, a focal point is the mitochondrial control of specific death enzymes--so called caspases--by members of the pro-apoptotic Bax and BH3 subfamily or the anti-apoptotic Bcl-2 subfamily. While the initiation of cell death happens through a variety of signalling systems, the activation of caspases plays a pivotal role in the progression towards the final morphologic findings in cells undergoing apoptosis. Caspases appear to directly cleave and inactivate substrates that are clinical for the maintenance of cell structure and function but also regulate the activity of other enzymes that induce the apoptotic phenotype within the cell. The insulin-like growth factors (IGFs) are potent proliferation factors and potently inhibit apoptosis acting via the ubiquitously expressed IGF-I receptor. Within IGF-I receptor signalling, key to the inhibition of apoptosis are the RAS/RAF/mitogen-activated protein (MAP)-kinase pathway and the PI 3'-kinase pathway. To give an example of high clinical relevance of apoptosis within endocrine disorders, apoptotic death of pancreatic beta cells in type 1 diabetes disease and the involvement of IGF-II in beta cell survival and beta cell function is discussed in detail. Finally, further understanding of signalling systems that are involved in proliferation or in apoptosis might provide novel tools to treat or even heal disorders like type I diabetes.

Clinical aspects of obesity in childhood and adolescence

The level of fatness of a child at which morbidity acutely and/or later in life increases is determined on an acturial basis. Direct measurements of body fat content, e.g. hydrodensitometry, bioimpedance, or DEXA, are useful tools in scientific studies. However, body mass index (BMI) is easy to calculate and is generally accepted now to be used to define obesity in children and adolescents clinically. An increased risk of death from cardiovascular disease in adults has been found in subjects whose BMI had been greater than the 75th percentile as adolescents. Childhood obesity seems to substantially increase the risk of subsequent morbidity whether or not obesity persists into adulthood. The genetic basis of childhood obesity has been elucidated to some extent through the discovery of leptin, the ob gene product, and the increasing knowledge on the role of neuropeptides such as POMC, neuropeptide Y (NPY) and the melanocyte concentrating hormone receptors (for example, MC4R). Environmental/exogenous factors largely contribute to the development of a high degree of body fatness early in life. Twin studies suggest that approximately 50% of the tendency toward obesity is inherited. There are numerous disorders including a number of endocrine disorders (Cushing's syndrome, hypothyroidism, etc.) and genetic syndromes (Prader-Labhard-Willi syndrome, Bardet Biedl syndrome, etc.) that can present with obesity. A simple diagnostic algorithm allows for the differentiation between primary or secondary obesity. Among the most common sequelae of primary childhood obesity are hypertension, dyslipidemia, back pain and psychosocial problems. Therapeutic strategies include psychological and family therapy, lifestyle/behaviour modification and nutrition education. The role of regular exercise and exercise programmes is emphasized. Surgical procedures and drugs used in adult obesity are still not generally recommended in children and adolescents with obesity. As obesity is the most common chronic disorder in industrialized societies, its impact on individual lives as well as on health economics has to be recognized more widely. This review is aimed towards defining the clinical problem of childhood obesity on the basis of current knowledge and towards outlining future research areas in the field of energy homoesostasis and food intake in relation to child health. Finally, one should aim to increase public awareness of the ever increasing health burden and economic dimension of the childhood obesity epidemic that is present around the globe.

Obesity in childhood and adolescence: clinical diagnosis and management

The industrialized countries around the world are experiencing an epidemic of childhood obesity. The level of fatness of a child at which morbidity increases acutely and/or later in life is determined on an individual basis. Overall, however, childhood obesity substantially increases the risk of subsequent morbidity whether or not obesity persists into adulthood. The genetic basis of childhood obesity has been elucidated to some extent through the discovery of leptin, the ob gene product, and the increasing knowledge of the role of neuropeptides such as pro-opiomelanocortin, neuropeptide Y and the melanocyte-concentrating hormone receptors. Environmental and exogenous factors are the main contributors to the development of a high degree of body fatness early in life. Studies involving twins suggest that approximately 50% of the tendency toward obesity is inherited. There are numerous disorders, including a number of endocrine disorders, such as Cushing's syndrome and hypothyroidism, and genetic syndromes, such as Prader-Labhard-Willi syndrome and Bardet-Biedl syndrome, that can present with obesity. A simple diagnostic algorithm allows for differentiation between primary and secondary obesity. Among the most common sequelae of primary childhood obesity are hypertension, dyslipidemia, back pain and psychosocial problems. It is somewhat ironic that the definition of obesity in childhood is not an easy one. Direct measurements of body fat content, such as hydrodensitometry, bioimpedance, or dual-energy X-ray absorptiometry, are useful tools in scientific studies. Body mass index (BMI) is, however, now generally accepted to be a good clinical measure for the definition of obesity in children and adolescents. In preadolescent boys, BMI also relates to muscle mass and should be used for the definition of fat mass with great caution. An increased risk of death from cardiovascular disease in adults has been found in patients whose BMI had been greater than the 75th percentile as adolescents. Therapeutic strategies include psychological and family therapy, modification of lifestyle and behavior, and nutritional education. The role of regular exercise and exercise programs is emphasized, while surgical procedures and drugs used in adult obesity are still not generally recommended for obese children. Obesity is the most common chronic disorder in industrialized countries, and its impact on individual lives as well as on health economics must be recognized by physicians and the public alike. This review aims to increase awareness of the health burden and economic dimension of the epidemic of childhood obesity that is occurring around the globe.