Role of the C1858T polymorphism of protein tyrosine phosphatase non-receptor type 22 (PTPN22) in children and adolescents with type 1 diabetes.

In recent years, increasing interest has been devoted to the susceptibility gene polymorphisms in type 1 diabetes (T1D) as well as in other autoimmune diseases. Among these, a nucleotide polymorphism of the gene encoding for the protein tyrosine phosphatase non-receptor type 22 (PTPN22) has been associated with T1D in several studies. The aim of this study is to define the frequency of the C1858T polymorphism in the PTPN22 gene in a cohort of 113 Caucasian patients (58 males and 55 females) with T1D, and to assess a possible correlation with a group of clinically relevant variables: age at onset, gender, diabetes-related autoantibodies, residual ß-cell function and daily insulin requirement (IR) 6 months after diagnosis. Using a PCR-RFLP approach, we evidenced a 17.7% frequency of the PTPN22 C1858T polymorphism in diabetic patients, higher than the frequency showed in the general population. A statistically significant correlation between this polymorphism and higher levels of C-peptide at diagnosis and lower IR at 6 months from diagnosis was observed (P=0.001 and P=0.04). Moreover, 1858T variant carriers were more frequently positive for glutamic acid decarboxylase (GAD) autoantibodies at diagnosis than wild-type subjects (P=0.19). On the other hand, no significant difference regarding age at onset, gender distribution, insulinoma-associated 2 molecule (IA2) and islet cell antibodies (ICA) positivity was found. These findings, if adequately confirmed in the future and extended to larger samples, may characterize a subset of T1D patients with a defined genetic pattern, who may be eligible for trials aimed to preserve residual ß-cell function in the coming years.

Insulin pump failures in Italian children with Type 1 diabetes: retrospective 1-year cohort study.

AIMS: Insulin pump failure and/or malfunction requiring replacement have not been thoroughly investigated. This study evaluated pump replacement in children and adolescents with Type 1 diabetes using insulin pump therapy. METHODS: Data were collected for all participants younger than 19 years, starting insulin pump therapy before 31 December 2013. For each child, age, disease duration, date of insulin pump therapy initiation, insulin pump model, failure/malfunction/replacement yes/no and reason were considered for the year 2013. RESULTS: Data were returned by 40 of 43 paediatric centres belonging to the Diabetes Study Group of the Italian Society of Paediatric Endocrinology and Diabetology. In total, 1574 of 11 311 (13.9%) children and adolescents with Type 1 diabetes were using an insulin pump: 29.2% Animas VIBE™ , 9.4% Medtronic MiniMed 715/515™ , 34.3% Medtronic MiniMed VEO™ , 24.3% Accu-Check Spirit Combo™ and 2.8% other models. In 2013, 0.165 insulin pump replacements per patient-year (11.8% due to pump failure/malfunction and 4.7% due to accidental damage) were recorded. Animas VIBE™ (22.1%) and Medtronic MiniMed VEO™ (17.7%) were the most replaced. CONCLUSIONS: In a large cohort of Italian children and adolescents with Type 1 diabetes, insulin pump failure/malfunction and consequent replacement are aligned with rates previously reported and higher in more sophisticated pump models.

Health-related quality of life and treatment preferences in adolescents with type 1 diabetes. The VIPKIDS study.

A multi-centre, observational, cross-sectional study was carried out to determine whether the health-related quality of life (HRQOL) of adolescents with type 1 diabetes is affected by different insulin treatment systems, and which features of HRQOL are impacted by the respective insulin treatment. The study regarded 577 adolescents, aged 10-17 years, with type 1 diabetes treated with continuous subcutaneous insulin infusion (CSII) (n = 306) or multiple daily injections (MDI) (n = 271). The Insulin Delivery System Rating Questionnaire was validated in Italian and was self-completed by the subjects during a routine visit to the centres. Subjects were compared following the domains of the questionnaire. Good HRQOL was seen in subjects treated with either MDI or CSII. Significant differences were not found in the domains for general diabetes, including diabetes worries, social burden and psychological well-being. Multiple quantile regression analysis showed that CSII confers significant advantages in terms of HRQOL with improvements in treatment satisfaction, perceived clinical efficacy and reduction in treatment interference with daily activities. This favourable impact was more evident in subjects reporting lower HRQOL scores, suggesting that CSII may be especially useful for individuals perceiving a poor HRQOL. Analysis of the domains indicated that CSII was associated with a higher HRQOL than MDI. Life-course HRQOL evaluation using a standardised questionnaire can ensure better chronic disease management. This is particularly important when providing individualised care for adolescents, as they become increasingly responsible for managing their diabetes.

Bone maturity and thyroidal status at birth: role of the ultrasonographic evaluation of the distal femoral epiphysis.

PURPOSE: Thyroidal hormones are important for bone development, and ultrasonographic (US) evaluation of the distal femoral epiphysis (DFE) has recently been suggested as a new method for the assessment of skeletal maturity in infants. A delayed bone maturation, expressed by a smaller or absent DFE nucleus (in terms of DFE surface area, sum of the epiphyseal diameters, or DFE height and acetabular size), has been largely demonstrated in diagnosed hypothyroid infants, while no data analyze the role and meaning of the DFE dimensions (in terms of volume) in newborn before knowledge of the congenital neonatal screening results. The aims of the present study were to ultrasonographically evaluate the volume of DFE in newborns, and to determine whether it has any predictive role for the thyroidal status at birth. MATERIALS AND METHODS: 238 newborns (M/F: 121 /117) were evaluated. The gestational age, body weight and length at birth were registered. Neonatal screening for congenital hypothyroidism (CH), based on TSH levels on blood spot, was performed in all on the 3 rd day of life. The DFE volume was ultrasonographically evaluated, taking into account the three diameters of the DFE nucleus, within 48 hours of birth. RESULTS: No newborn was found to have CH on neonatal screening. The DFE volume ranged between 0.00 cm and 0.61 cm (mean 0.14 ± 0.10 cm, median 0.13 cm). The DFE volume did not differ between males and females, while it was significantly greater in at term babies than in preterm babies. No differences in TSH values at screening were noted among the groups. The DFE volume was significantly related to gestational age, birth weight and length. A significant relationship was found between the DFE volume and TSH concentrations at screening. CONCLUSION: US evaluation of DFE volume provides a simple method for assessing bone maturity at birth, which is related to gestational age, body weight and length at birth. Nonetheless, it has any predictive role for thyroidal status at birth, being not related to TSH levels on neonatal screening for CH.

Molecular characterization of 6 unrelated Italian patients with 5alpha-reductase type 2 deficiency.

Steroid 5alpha-reductase (5alphaR) deficiency (OMIM number #264600) is a rare 46,XY disorder of sex differentiation caused by mutations in the 5alphaR type 2 gene (SRD5A2) resulting in dihydrotestosterone deficiency during fetal development. We report on the analysis of the SRD5A2 gene in 6 unrelated 46,XY Italian patients with external genitalia morphology ranging from predominantly female to nearly completely male. Three subjects were seen and assessed at birth, 1 patient was referred to us before puberty, and 2 at postpubertal age. Six different causative mutations (5 missense and 1 nonsense) and a rare polymorphism were identified. Four patients presented homozygous single-base substitutions. These SRD5A2 mutations were located in exon 2 (variant Cys133Gly), exon 4 (Gly196Ser and Ala207Asp) and exon 5 (Tyr235Phe). A fifth subject was a compound heterozygote who carried a nonsense mutation in exon 1 (Trp53X) and a second SRD5A2 alteration in exon 5 (Tyr235Phe). The final patient presented a mutation in only 1 allele (Gly34Trp) together with the Ala49Thr variant. The molecular characterization of these patients made it possible to identify novel mutations and to confirm, before gender assignment or any surgical approach, the suspected 5alphaR deficiency in 2 newborns, 1 of whom had inconclusive hormonal data. 5alphaR deficiency in subjects without parental consanguinity and the presence of compound heterozygotic patients suggest that SRD5A2 mutations carrier frequency may be higher than previously thought.

Early diagnosis of 5alpha-reductase deficiency in newborns.

5Alpha-reductase-2 deficiency is a rare autosomal recessive form of 46,XY disorders of sex differentiation (DSD), caused by mutations in the steroid 5alpha-reductase type 2 gene (SRD5A2), presenting at birth with variable degrees of undervirilization. We report on three Italian newborns with 46,XY DSD in whom the evaluation of testosterone, dihydrotestosterone, testosterone/dihydrotestosterone (T/DHT) ratio and molecular analysis of the 5alpha-reductase type 2 gene was made in their first month of life. Baseline T/DHT ratio suggested 5alpha-reductase-2 deficiency; the diagnosis was confirmed by molecular genetics (homozygous mutation in exon 4 [G196S], heterozygous mutation in exon 1 and 5 [W35X/Y235F], heterozygous mutation plus polymorphism in exon 1 [G34W/A49T]). Proper investigation permitted early reassignment to male sex in two babies, assigned to female sex just after birth. In infancy, the T/DHT ratio, assessed by suitable assay methods and evaluated by age-appropriate reference values, seems to be able to select newborns affected by 5alpha-reductase-2 deficiency. Molecular analysis of the SRD5A2 gene should be warranted in newborns with abnormal ratio before sex assignment.

HLA DR/DQ alleles and risk of type I diabetes in childhood: a population-based case-control study.

The objective was to evaluate HLA DR/DQ alleles and their risk factor for type 1 diabetes in the Abruzzo region (central Italy). Sixty incident cases from the Abruzzo region were studied together with 120 unrelated control subjects living in the same administrative areas. The relative risk of diabetes associated with the alleles under study was calculated by deriving the odds ratio (OR) maximum likelihood estimates and their 95% confidence intervals (CI) by the exponentiation of the logistic regression beta-parameter. The combination DRB1*03/DQA1*0501/DQB1*0201 was found in 20.0% of patients and 7.1% of the control subjects, conferring an OR of 4.04 and a CI of 1.97-8.49. The combination DRB1*04/DQA1*0301/DQB1*0302 was found in 23.3% of diabetic patients and 6.7% of controls, giving an OR of 5.69 and a CI of 2.77-12.05. DRB1*11/DQA1*0505/DQB1*0301 and DQA1*0505/DQB1*0301 were negatively associated with type 1 diabetes (OR=0.27, CI 0.11-0.57; OR=0.07, CI 0.02-0.19). The DQA1 genotype at risk was found to be DQA1*0301/DQA1*0501: OR=23.80, CI 2.97-190.89, as it occurred with the highest frequency in the patient group. The DQB1 genotype at risk was found to be DQB1*0201/DQB1*0302, which occurred in 13.3% of patients but in only 1.1% of the control group (OR=29.75, CI 5.36-549.25). Our results shed further light on the risk of development of this disease during a specific time period in an area where the overall incidence of type 1 diabetes is known.

Enhanced soluble CD40 ligand contributes to endothelial cell dysfunction in vitro and monocyte activation in patients with diabetes mellitus: effect of improved metabolic control.

AIMS/HYPOTHESIS: Inflammation plays a pathogenic role in the development of accelerated atherosclerosis in diabetes. Soluble CD40 ligand (sCD40L) is enhanced in diabetes; however, the molecular mechanisms linking sCD40L to accelerated atherosclerosis in diabetes are still unclear. We tested the hypothesis that sCD40L may be involved in the vascular complications in diabetes and exerts its effect by triggering inflammatory reactions on mononuclear and endothelial cells (ECs). METHODS: We studied 70 patients, 40 with type 2 and 30 with type 1 diabetes, with a history or physical examination negative for cardiovascular disease, and 40 non-diabetic and 30 healthy subjects, matched with the type 2 and type 1 diabetic patients, respectively. Plasma and serum sCD40L, and plasma soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, E-selectin and monocyte chemo-attractant protein-1 (MCP-1) were measured. Adhesion molecules and MCP-1 release, the ability to repair an injury in ECs, and O2- generation in monocytes were analysed in vitro after stimulation with serum from patients or controls. RESULTS: Type 2 and type 1 diabetic patients had significantly higher sCD40L levels than controls. Furthermore, high sCD40L was associated with in vitro adhesion molecules and MCP-1 release, impaired migration in ECs and enhanced O2- generation in monocytes. Improved metabolic control was associated with a reduction of plasma sCD40L by 37.5% in 12 type 1 diabetic patients. Furthermore, elevated sCD40L in diabetic patients was significantly correlated with HbA1c levels. CONCLUSIONS/INTERPRETATION: Upregulation of sCD40L as a consequence of persistent hyperglycaemia in diabetic patients results in EC activation and monocyte recruitment to the arterial wall, possibly contributing to accelerated atherosclerosis development in diabetes.

Relationship between reduced BCL-2 expression in circulating mononuclear cells and early nephropathy in type 1 diabetes.

Microalbuminuria is the earliest clinical evidence of diabetic nephropathy, but the mechanisms linking hyperglycemia and kidney complications are not clear. The aim of this study was to evaluate whether enhanced oxidative stress in patients with microalbuminuria can contribute to diabetic nephropathy development through downregulation of the antiapoptotic gene Bcl-2 that promotes in turn a pro-inflammatory status. We studied 30 patients with type 1 diabetes (15 with and 15 without microalbuminuria) compared to 15 matched healthy controls. Plasma oxidant status, and expression of Bcl-2, activated NF-kB, inducible Nitric Oxide synthase (iNOS), and monocyte chemoattractant protein (MCP)-1 in circulating monocytes were evaluated at baseline and after 8-week oral vitamin E treatment (600 mg b.i.d.). Bcl-2 expression was significantly reduced in microalbuminuric diabetic patients as a consequence of increased oxidant burden secondary to persistent hyperglycemia. Bcl-2 down-regulation was associated with enhanced expression of NF-kB, iNOS and MCP-1, and showed a strong correlation with the albumin excretion rate. Low Bcl-2 expression and high inflammatory status were normalized by vitamin E both in vivo and in vitro. Our study showed that Bcl-2 down-regulation in diabetic patients with poor glycemic control results in the activation of the NF-kB pathway leading to the development of nephropathy. Vitamin E might provide a novel form of therapy for prevention of nephropathy in diabetic patients in which an acceptable glycemic control is difficult to achieve despite insulin therapy.

Screening for vascular complications in children and adolescents with type 1 diabetes mellitus.

Type 1 diabetes mellitus poses a significant health burden, particularly as a result of its microvascular complications. Clinically evident diabetes-related microvascular complications are extremely rare in childhood and adolescence. However, early functional and structural abnormalities may be present a few years after the onset of the disease. Therefore, regular screening for diabetic microvascular disease, particularly retinopathy and nephropathy, are of foremost importance in paediatric diabetes care. Early detection of diabetic microangiopathy and timely treatment of early signs of these complications have a pivotal role in prevention of blindness and end-stage renal failure in children and adolescents with diabetes.

The effect of subclinical hypothyroidism on metabolic control in children and adolescents with Type 1 diabetes mellitus.

AIMS: Associated autoimmune phenomena might influence metabolic control in children and adolescents with Type 1 diabetes mellitus. A retrospective case control study was performed in order to explore the effect of subclinical hypothyroidism on metabolic control in Type 1 diabetes mellitus. PATIENTS AND METHODS: For this purpose each patient with Type 1 diabetes and subclinical hypothyroidism (cases) was matched for age, duration of disease and, if possible, for sex, with two to three diabetic patients without hypothyroidism (controls). Parameters of metabolic control such as HbA1c, total insulin requirement and frequency of symptomatic hypoglycaemia were retrieved for 12, 6 and 3 months before and after diagnosis of hypothyroidism. RESULTS: Thirteen patients (two male/11 female) patients were diagnosed with subclinical hypothyroidism and were matched with 31 controls (nine male/22 female). There was no difference (mean and range) in terms of age (11.9 years (4.4-18.1) vs. 11.7 years (3.5-18.1), P = 0.9) and duration of disease (5.1 years (1.2-10.5) vs. 4.38 years (0.9-10.8), P = 0.6) between the two groups. There was no difference in HbA1c and total insulin requirement between the two groups at any time point of assessment (anova P = 0.8 and P = 0.1, respectively). Patients with hypothyroidism had significantly more symptomatic hypoglycaemic episodes during the 12 months before diagnosis (anova P = 0.05), increasing progressively during this time period and reaching a peak at time 0 (5.5+/-0.4 vs. 1.6+/-0.1 episodes/month, P = 0.01). No difference could be detected within 6 months of starting substitution therapy (2.4+/-0.2 vs. 1.6+/-0.1 episodes/week, P = 0.8). CONCLUSIONS: These data suggest that subclinical hypothyroidism is associated with an increased risk of symptomatic hypoglycaemia. The prompt introduction of substitution therapy is recommended as it reduces its frequency.

Serum angiogenin concentrations in young patients with diabetes mellitus.

BACKGROUND: Angiogenin serum levels were measured in a large group of type 1 diabetic young patients, looking at whether increased Angiogenin concentrations are associated with long-term glycemic control and microvascular complications. MATERIALS AND METHODS: Four groups of patients were compared to 223 age- and sex- matched healthy controls: 196 type 1 diabetic patients (age range 3-24 years, onset of diabetes before the age of 12 years; duration of disease longer than 2 years), without microvascular complications were divided into three groups on the basis of age (group 1, n = 37, age < 6 years; group 2, n = 71, age 6-12 years; group 3, n = 88, age > 12 years); 53 adolescents and young adults (age 16.1-29.7 years) with diabetic microvascular complications (background, preproliferative or proliferative retinopathy, albumin excretion rate 20-200 microg min-1) (group 4). RESULTS: Angiogenin serum levels were significantly increased in diabetic pre-school and pre-pubertal children, and particularly elevated in pubertal subjects compared with age- and sex-matched controls. Adolescents and young adults with microvascular complications had very high angiogenin concentrations. One-year mean HbA1c values were correlated with angiogenin levels (r = 0.389; p < 0.01). In poorly controlled diabetics (HbA1c > 10%), long-term (2 years) improvement of glycemic control determined a significant reduction of angiogenin concentrations in both pre-school and pre-pubertal children as well as in pubertal youngsters. CONCLUSIONS: Angiogenin serum concentrations are increased in diabetic children even before puberty. Severity of microvascular complications is associated with markedly increased angiogenin serum levels. Long-term tight glycemic control determines a consistent reduction of angiogenin concentrations.

Increased vascular endothelial growth factor serum concentrations may help to identify patients with onset of type 1 diabetes during childhood at risk for developing persistent microalbuminuria.

This study was designed to evaluate whether vascular endothelial growth factor serum concentrations may identify adolescents with onset of type 1 diabetes during childhood at greater risk to develop persistent microalbuminuria and incipient diabetic nephropathy. In January 1989, vascular endothelial growth factor serum levels were measured in 101 normoalbuminuric diabetic children and adolescents (aged 7-14.9 yr; onset of diabetes before age 18 yr; duration of diabetes >7 yr). Participants were clinically examined at baseline and annually thereafter. Vascular endothelial growth factor serum concentrations were measured every year during the 8-yr follow-up period. Over 8 yr, 11 of 101 patients (10.9%) developed persistent microalbuminuria; no patient developed overt nephropathy. The risk of developing microalbuminuria was higher in children with increased vascular endothelial growth factor serum levels (using 160 pg/ml as the arbitrary cut-off point; group 1) compared with those with normal vascular endothelial growth factor serum levels at the beginning of the study (group 2; 19.2 vs. 2.0%; P < 0.01; sensitivity, 90.9%; specificity, 53.3%). The odds ratio for the occurrence of microalbuminuria after adjustment for confounding variables (albumin excretion rate, sex, hemoglobin A(1c), mean blood pressure, cholesterol, and triglycerides) in type 1 diabetic adolescents with elevated vascular endothelial growth factor serum levels was 4.1 (95% confidence interval, 2.0-10.9). These results suggest that vascular endothelial growth factor serum concentrations may be one of the predictors and risk factors for microalbuminuria and incipient diabetic nephropathy in adolescents and young adults with onset of diabetes during childhood. Persistently increased vascular endothelial growth factor serum levels may help to identify normotensive, normoalbuminuric patients with type 1 diabetes who are predisposed to develop persistent microalbuminuria later in life.

Celiac disease in children and adolescents with type I diabetes: importance of hypoglycemia.

BACKGROUND: Symptomatic hypoglycemia is an unavoidable problem in the treatment of type I diabetes. Celiac disease is associated with malabsorption and may therefore represent an important risk factor. METHODS: The frequency of symptomatic hypoglycemia in patients with type I diabetes and celiac disease (cases) was compared with those of patients who had diabetes without celiac disease (controls). For this purpose, each case was matched for age, sex, and duration of disease with one to two control patients. Indices of metabolic control (hemoglobin [Hb]A1c, frequency of hypoglycemia, and total insulin requirement) were retrieved for the 18 months before and after diagnosis of celiac disease. RESULTS: Eighteen patients (6 males and 12 females) had diagnosed celiac disease and were matched with 26 control patients (10 males and 16 females). There was no difference in age (11.0 years; range, 1.8-21.9 vs. 13.1 years; range, 2.3-22; P = 0.3) and duration of disease (8.4 years; range, 1.2-19.3 vs. 8.3 years; range, 1.1-18.7; P = 0.3) between the two groups. During the 6 months before and after diagnosis of celiac disease the cases had significantly more hypoglycemic episodes than the controls (means +/- SD; 4.5+/-4 vs. 2.0+/-2.2 episodes/months, P = 0.01). This was reflected by a progressive reduction in insulin requirement over the 12 months before diagnosis reaching a nadir at time 0 (0.6+/-0.2 vs. 0.9+/-0.3, P = 0.05). CONCLUSION: These data suggest that underlying celiac disease is associated with an increased risk of symptomatic hypoglycemia and that the introduction of a gluten-free diet with normalization of the intestinal mucosa may reduce its frequency.

Vascular endothelial growth factor (VEGF) in children, adolescents and young adults with Type 1 diabetes mellitus: relation to glycaemic control and microvascular complications.

AIMS: To evaluate serum levels of vascular endothelial growth factor (VEGF) in a large group of children, adolescents and young adults with Type 1 diabetes mellitus to investigate whether increased VEGF concentrations are associated with long-term glycaemic control and microvascular complications. METHODS: The study involved 196 patients with Type 1 diabetes mellitus (age range 2-24 years, onset of diabetes before the age of 12 years, duration of disease longer than 2 years), without clinical and laboratory signs of microvascular complications; they were divided into three groups (group 1 - n = 37, age < 6 years; group 2 - n = 71, age 6-12 years; group 3 - n = 88, age > 12 years). Fifty-three adolescents and young adults (age 16.1-29.7) with different grades of diabetic retinopathy and microalbuminuria were also selected (group 4). A total of 223 healthy controls were matched for age and sex with each group of patients with diabetes mellitus. RESULTS: VEGF serum levels were significantly increased in pre-school and pre-pubertal children with diabetes as well as in pubertal patients compared to controls. VEGF concentrations were markedly increased in adolescents and young adults with microvascular complications compared with both healthy controls and diabetic patients without retinopathy or nephropathy. Multivariate analysis showed that elevation of VEGF in serum was an independent correlate of complications. One-year mean HbA1c values were significantly correlated with VEGF concentrations (r = 0.372; P < 0.01). Children with HbA1c levels greater than 10% had significantly higher VEGF concentrations when compared with matched patients whose HbA1c levels were lower than 10%. In poorly controlled diabetic children (HbA1c > 10%), long-term (2 years) improvement of glycaemic control (aiming at HbA1c < 7%) resulted in a significant reduction of VEGF levels. CONCLUSIONS: VEGF serum concentrations are increased in prepubertal and pubertal children with diabetes. Glycaemic control influences VEGF serum levels. Severity of microvascular complications is associated with marked increase of VEGF concentrations in the serum of these patients.

Homocysteine levels during fasting and after methionine loading in adolescents with diabetic retinopathy and nephropathy.

OBJECTIVE: To assess plasma homocysteine levels in adolescents and young adults with type 1 (insulin-dependent) diabetes with and without microvascular complications. STUDY DESIGN: Homocysteine levels were measured during fasting and after methionine loading in plasma of 61 patients with onset of diabetes before the age of 12 years and duration of disease longer than 7 years. They had an albumin excretion rate (AER) between 20 and 200 microg/min in 2 of 3 overnight urine collections in a period of 6 months and/or retinopathy. Patients with persistent microalbuminuria were divided into 2 groups: subjects with AER of 20 to 70 microg/min and patients with AER of 70 to 200 microg/min. Adolescents (n = 54) without signs of diabetic retinopathy or nephropathy and matched control subjects (n = 63) were also studied. RESULTS: Homocysteine concentrations before and after methionine load were higher in adolescents with diabetic complications than in healthy subjects (fasting values: 12. 4 +/- 7.9 micromol/L vs 7.8 +/- 4.2 micromol/L; P <.01; after methionine load: 28.1 +/- 13.2 micromol/L vs 16.6 +/- 7.3 micromol/L; P <.005). Values of 11.9 micromol/L or higher were considered to constitute fasting hyperhomocysteinemia. The increase of homocysteine concentrations was particularly evident in young diabetic patients with AER >70 microg/min (fasting values: 14.7 +/- 5.6 micromol/L; after methionine load: 34.2 +/- 12.6 micromol/L) and in patients with proliferative retinopathy (fasting values: 15.1 +/- 5.0 micromol/L; after methionine load: 36.8 +/- 12.5 micromol/L). CONCLUSIONS: Increased plasma homocysteine concentrations may contribute to increased morbidity and death from cardiovascular disease in adolescents and young adults with diabetic retinopathy and nephropathy.

Advanced glycation end products in adolescents and young adults with diabetic angiopathy.

The aim of this study was to evaluate serum advanced glycation end products (S-AGEs) in a group of adolescents and young adults with type 1 (insulin-dependent) diabetes mellitus and with diabetic microvascular complications (nephropathy or retinopathy). Fifty-two patients were included in the study (age range 14.2-28.8 years, onset of diabetes before the age of 12 years, duration of diabetes longer than 7 years); 45 patients without diabetic angiopathy and 63 healthy controls were also selected. S-AGEs were significantly increased in patients with diabetic angiopathy compared with controls (19.9+/-3.8 vs. 11.8+/-2.8 U/ml, P<0.001). Higher S-AGE levels were found in patients with severe diabetic nephropathy and retinopathy. When the albumin excretion rate (AER) was >100 microg/min per 1.73 m2, S-AGE levels were 23.1+/-2.4 U/ml; when the AER was 50-100 microg/min per 1.73 m2 levels were 19.8+/-1.9 U/ml, and for an AER of 20-50 microg/min per 1.73 m2 the corresponding value was 16.1+/-2.1 U/ml (P<0.005). Patients with proliferative retinopathy had S-AGE levels of 22.2+/-2.6 U/ml, those with preproliferative retinopathy 20.7+/-2.2 U/ml, and background retinopathy 17.6+/-1.9 U/ml (P<0.01). A significant correlation was found between levels of glycosylated hemoglobin (HbA1c) and S-AGE (r=0.43, P<0.01). S-AGE concentrations are markedly increased in type 1 diabetic adolescents and young adults with diabetic nephropathy and retinopathy. The severity of diabetic angiopathy is related to the serum levels of AGEs.