Prevalence of structural central nervous system abnormalities in early-onset type 1 diabetes mellitus

Psychodiabetology: The Challenge of the Future?

The number of people suffering from diabetes, including type 1, is constantly increasing both in Poland and worldwide. Type 1 diabetes is a chronic disease characterized by uncertain prognosis and relapses, as well as permanent, irreversible, and progressive changes in health status. The ongoing disease results in dysfunction or disability, and the patient requires specialized supervision, care, and rehabilitation. However, the success of therapy does not depend solely on the perfection of treatment, but also on the patient's readiness to change their lifestyle and cooperate with the therapeutic team. The patient's constant alertness in making therapeutic decisions does not always lead to expected treatment results, and the risk of hypoglycemia associated with intensive insulin treatment depletes the patient's motivation for treatment, leading over time to the development of 'therapeutic burnout' and psychiatric disorders. This narrative review is an attempt to summarize the knowledge and possible future solutions in diabetes type 1 in Poland as well as highlight the importance of comprehensive care, including psychological care, which appears fundamental in a chronic disease such as type 1 diabetes. Therefore, the aim of the study was to present generational changes and psychosocial problems of patients with type 1 diabetes and to identify urgent challenges in diabetic care. Attention should be paid to the deteriorating mental condition of the young generations, who, in the course of diabetes, are exposed to additional psychological and psychiatric health problems. The next generation of patients will require more psychological care, which is why the challenge of the future is to create psychodiabetology centers.

The Advanced Diabetes Technologies for Reduction of the Frequency of Hypoglycemia and Minimizing the Occurrence of Severe Hypoglycemia in Children and Adolescents with Type 1 Diabetes

Hypoglycemia is an often-observed acute complication in the management of children and adolescents with type 1 diabetes. It causes inappropriate glycemic outcomes and may impair the quality of life in the patients. Severe hypoglycemia with cognitive impairment, such as a convulsion and coma, is a lethal condition and is associated with later-onset cognitive impairment and brain-structural abnormalities, especially in young children. Therefore, reducing the frequency of hypoglycemia and minimizing the occurrence of severe hypoglycemia are critical issues in the management of children and adolescents with type 1 diabetes. Advanced diabetes technologies, including continuous glucose monitoring and sensor-augmented insulin pumps with low-glucose suspension systems, can reduce the frequency of hypoglycemia and the occurrence of severe hypoglycemia without aggravating glycemic control. The hybrid closed-loop system, an automated insulin delivery system, must be the most promising means to achieve appropriate glycemic control with preventing severe hypoglycemia. The use of these advanced diabetes technologies could improve glycemic outcomes and the quality of life in children and adolescents with type 1 diabetes.

The impact of type 1 diabetes mellitus in childhood on academic performance: A matched population-based cohort study

BACKGROUND AND OBJECTIVE

The impact of type 1 diabetes mellitus (T1D) on academic performance is inconclusive. This study aims to compare scholastic performance and high-school completion in young people hospitalized with T1D compared to matched peers not hospitalized with diabetes.

RESEARCH DESIGN

Retrospective case-comparison cohort study.

METHOD

A population-level matched case-comparison study of people aged ≤18 hospitalized with T1D during 2005-2018 in New South Wales, Australia using linked health-related and education records. The comparison cohort was matched on age, gender, and residential postcode. Generalized linear mixed modeling examined risk of school performance below the national minimum standard (NMS) and generalized linear regression examined risk of not completing high school for young people hospitalized with T1D compared to peers. Adjusted relative risks (ARR) were calculated.

RESULTS

Young females and males hospitalized with T1D did not have a higher risk of not achieving the NMS compared to peers for numeracy (ARR: 1.19; 95%CI 0.77-1.84 and ARR: 0.74; 95%CI 0.46-1.19) or reading (ARR: 0.98; 95%CI 0.63-1.50 and ARR: 0.85; 95%CI 0.58-1.24), respectively. Young T1D hospitalized females had a higher risk of not completing year 11 (ARR: 1.73; 95%CI 1.19-2.53) or 12 (ARR: 1.65; 95%CI 1.17-2.33) compared to peers, while hospitalized T1D males did not.

CONCLUSIONS

There was no difference in academic performance in youth hospitalized with T1D compared to peers. Improved glucose control and T1D management may explain the absence of school performance decrements in students with T1D. However, females hospitalized with T1D had a higher risk of not completing high school. Potential associations of this increased risk, with attention to T1D and psycho-social management, should be investigated.

Impact of glucose metabolism on the developing brain

Glucose is the most important substrate for proper brain functioning and development, with an increased glucose consumption in relation to the need of creating new brain structures and connections. Therefore, alterations in glucose homeostasis will inevitably be associated with changes in the development of the Nervous System. Several studies demonstrated how the alteration of glucose homeostasis - both hyper and hypoglycemia- may interfere with the development of brain structures and cognitivity, including deficits in intelligence quotient, anomalies in learning and memory, as well as differences in the executive functions. Importantly, differences in brain structure and functionality were found after a single episode of diabetic ketoacidosis suggesting the importance of glycemic control and stressing the need of screening programs for type 1 diabetes to protect children from this dramatic condition. The exciting progresses of the neuroimaging techniques such as diffusion tensor imaging, has helped to improve the understanding of the effects, outcomes and mechanisms underlying brain changes following dysglycemia, and will lead to more insights on the physio-pathological mechanisms and related neurological consequences about hyper and hypoglycemia.

Pre-school and school-aged children benefit from the switch from a sensor-augmented pump to an AndroidAPS hybrid closed loop: A retrospective analysis

OBJECTIVE

Data on closed loop systems in young children with type 1 diabetes (T1D) are limited. We tested the efficacy and safety of an open-source, do-it-yourself automated insulin delivery system AndroidAPS in preschool and school-aged children.

RESEARCH DESIGN AND METHODS

This retrospective study analyzed diabetes control in 18 preschool (3-7 years) and 18 school-aged children (8-14 years) with T1D who switched from a sensor-augmented pump (SAP) to AndroidAPS. We compared the CGM parameters and HbA1c levels 3 months before and 6 months after the initiation of AndroidAPS therapy and evaluated frequency of severe adverse events during AndroidAPS use, the most frequent reasons for its interruption, and the experience and psychosocial benefits of AndroidAPS use.

RESULTS

General glycemic control was significantly improved after the switch from SAP to AndroidAPS. Time in range (TIR) increased in both preschool (70.8%-78.6%, p = 0.004) and school-aged children (77.2%-82.9%, p < 0.001), whereas HbA1c levels decreased (preschool children 53.8-48.5 mmol/mol, p < 0.001; school-aged children 52.6-45.1 mmol/mol, p = 0.001). Time spent in range of 3.0-3.8 mmol/L increased slightly in school children (2.6%-3.8%, p = 0.040), but not in preschool children (3.0%-3.0%, p = 0.913). Time spent at <3 mmol/L remained unchanged in both preschool (0.95%-0.67%, p = 0.432) and school-aged children (0.8%-0.8%, p = 1.000). No episodes of severe hypoglycemia or DKA and significant improvement of quality of life were reported by AndroidAPS users.

CONCLUSIONS

AndroidAPS seems effective for T1D control both in preschool and school-age children but further validation by prospective studies is necessary.

Impact of Type 1 Diabetes in the Developing Brain in Children: A Longitudinal Study

OBJECTIVE

To assess whether previously observed brain and cognitive differences between children with type 1 diabetes and control subjects without diabetes persist, worsen, or improve as children grow into puberty and whether differences are associated with hyperglycemia.

RESEARCH DESIGN AND METHODS

One hundred forty-four children with type 1 diabetes and 72 age-matched control subjects without diabetes (mean ± SD age at baseline 7.0 ± 1.7 years, 46% female) had unsedated MRI and cognitive testing up to four times over 6.4 ± 0.4 (range 5.3-7.8) years; HbA_1c and continuous glucose monitoring were done quarterly. FreeSurfer-derived brain volumes and cognitive metrics assessed longitudinally were compared between groups using mixed-effects models at 6, 8, 10, and 12 years. Correlations with glycemia were performed.

RESULTS

Total brain, gray, and white matter volumes and full-scale and verbal intelligence quotients (IQs) were lower in the diabetes group at 6, 8, 10, and 12 years, with estimated group differences in full-scale IQ of -4.15, -3.81, -3.46, and -3.11, respectively (P < 0.05), and total brain volume differences of -15,410, -21,159, -25,548, and -28,577 mm³ at 6, 8, 10, and 12 years, respectively (P < 0.05). Differences at baseline persisted or increased over time, and brain volumes and cognitive scores negatively correlated with a life-long HbA_1c index and higher sensor glucose in diabetes.

CONCLUSIONS

Detectable changes in brain volumes and cognitive scores persist over time in children with early-onset type 1 diabetes followed longitudinally; these differences are associated with metrics of hyperglycemia. Whether these changes can be reversed with scrupulous diabetes control requires further study. These longitudinal data support the hypothesis that the brain is a target of diabetes complications in young children.

Neurological Characteristics of Pediatric Glycogen Storage Disease

Glycogen storage diseases (GSD) encompass a group of rare inherited diseases due dysfunction of glycogen metabolism. Hypoglycemia is the most common primary manifestation of GSD, and disturbances in glucose metabolism can cause neurological damage. The aims of this study were to first investigate the metabolic, genetic, and neurological profiles of children with GSD, and to test the hypothesis whether GSD type I would have greater neurological impact than GSD type IX. A cross-sectional study was conducted with 12 children diagnosed with GSD [Types: Ia (n=5); 1, Ib (n=1); 4, IXa (n=5); and 1, IXb (n=1)]. Genetic testing was conducted for the following genes using multigene panel analysis. The biochemical data and magnetic resonance imaging of the brain presented by the patients were evaluated. The criteria of adequate metabolic control were adopted based on the European Study on Glycogen Storage Disease type I consensus. Pathogenic mutations were identified using multigene panel analyses. The mutations and clinical chronology were related to the disease course and neuroimaging findings. Adequate metabolic control was achieved in 67% of patients (GSD I, 43%; GSD IX, 100%). Fourteen different mutations were detected, and only two co-occurring mutations were observed across families (G6PC c.247C>T and c.1039C>T). Six previously unreported variants were identified (5 PHKA2; 1 PHKB). The proportion of GSD IX was higher in our cohort compared to other studies. Brain imaging abnormalities were more frequent among patients with GSD I, early-symptom onset, longer hospitalization, and inadequate metabolic control. The frequency of mutations was similar to that observed among the North American and European populations. None of the mutations observed in PHKA2 have been described previously. Therefore, current study reports six GSD variants previously unknown, and neurological consequences of GSD I. The principal neurological impact of GSD appeared to be related to inadequate metabolic control, especially hypoglycemia.

Structural Alterations in Deep Brain Structures in Type 1 Diabetes

Even though well known in type 2 diabetes, the existence of brain changes in type 1 diabetes (T1D) and both their neuroanatomical and clinical features are less well characterized. To fill the void in the current understanding of this disease, we sought to determine the possible neural correlate in long-duration T1D at several levels, including macrostructural, microstructural cerebral damage, and blood flow alterations. In this cross-sectional study, we compared a cohort of 61 patients with T1D with an average disease duration of 21 years with 54 well-matched control subjects without diabetes in a multimodal MRI protocol providing macrostructural metrics (cortical thickness and structural volumes), microstructural measures (T1-weighted/T2-weighted [T1w/T2w] ratio as a marker of myelin content, inflammation, and edema), and cerebral blood flow. Patients with T1D had higher T1w/T2w ratios in the right parahippocampal gyrus, the executive part of both putamina, both thalami, and the cerebellum. These alterations were reflected in lower putaminal and thalamic volume bilaterally. No cerebral blood flow differences between groups were found in any of these structures, suggesting nonvascular etiologies of these changes. Our findings implicate a marked nonvascular disruption in T1D of several essential neural nodes engaged in both cognitive and motor processing.

Brain Function Differences in Children With Type 1 Diabetes: A Functional MRI Study of Working Memory

Glucose is a primary fuel source to the brain, yet the influence of dysglycemia on neurodevelopment in children with type 1 diabetes remains unclear. We examined brain activation using functional MRI in 80 children with type 1 diabetes (mean ± SD age 11.5 ± 1.8 years; 46% female) and 47 children without diabetes (control group) (age 11.8 ± 1.5 years; 51% female) as they performed a visuospatial working memory (N-back) task. Results indicated that in both groups, activation scaled positively with increasing working memory load across many areas, including the frontoparietal cortex, caudate, and cerebellum. Between groups, children with diabetes exhibited reduced performance on the N-back task relative to children in the control group, as well as greater modulation of activation (i.e., showed greater increase in activation with higher working memory load). Post hoc analyses indicated that greater modulation was associated in the diabetes group with better working memory function and with an earlier age of diagnosis. These findings suggest that increased modulation may occur as a compensatory mechanism, helping in part to preserve working memory ability, and further, that children with an earlier onset require additional compensation. Future studies that test whether these patterns change as a function of improved glycemic control are warranted.

Improving pediatric endocrinology trainees' knowledge about insulin pumps and continuous glucose monitors with online spaced education: Technology Knowledge Optimization in T1D (TeKnO T1D)

OBJECTIVE

We explored the impact of TeKnO T1D, an online, case-based, spaced education curriculum about insulin pump and continuous glucose monitor (CGM) use in pediatric type 1 diabetes management.

METHODS

Pediatric endocrinology fellows (n = 64) were randomized to receive an educational curriculum focused on either insulin pumps or CGMs. Fellows received interactive questions twice weekly via email or mobile app. Median time to completion was 76.5 days. The primary outcome was change in knowledge as measured by performance on multiple-choice questions (MCQ) from the pre-test to the post-test.

RESULTS

Forty-eight of 64 (75%) learners completed the curriculum and assessments. The pump group improved from 35.0 ± 15% on the pre-test MCQs to 61.1 ± 17% on the post-test, a 12.2 absolute percentage point greater improvement on pump-specific items than the CGM group (P = .03). The CGM group improved from 30.3 ± 15% on the pre-test MCQs to 61.4 ± 21% on the post-test, a 28.7 absolute percentage point greater improvement on CGM-specific items than the pump group (P < .001). Both groups were more likely to report an appropriate level of understanding of their respective technologies after completing the corresponding curriculum. In thematic analysis of qualitative data, fellows indicated that knowledge gains led to improved patient care. There was universal agreement about enjoyment and effectiveness of the curricula.

CONCLUSIONS

TeKnO T1D proved to be an engaging, effective way to improve endocrinology fellows' knowledge and confidence about insulin pumps and CGM use in the management of pediatric type 1 diabetes.

Severe Hypoglycemia: Is It Still a Threat for Children and Adolescents With Type 1 Diabetes?

Severe hypoglycemia is defined as a condition with serious cognitive dysfunction, such as a convulsion and coma, requiring external help from other persons. This condition is still lethal and is reported to be the cause of death in 4-10% in children and adolescents with type 1 diabetes. The incidence of severe hypoglycemia in the pediatric population was previously reported as high as more than 50-100 patient-years; however, there was a decline in the frequency of severe hypoglycemia during the past decades, and relationship with glycemic control became weaker than previously reported. A lot of studies have shown the neurological sequelae with severe hypoglycemia as cognitive dysfunction and abnormalities in brain structure. This serious condition also provides negative psychosocial outcomes and undesirable compensatory behaviors. Various possible factors, such as younger age, recurrent hypoglycemia, nocturnal hypoglycemia, and impaired awareness of hypoglycemia, are possible risk factors for developing severe hypoglycemia. A low HbA_1c level is not a predictable value for severe hypoglycemia. Prevention of severe hypoglycemia remains one of the most critical issues in the management of pediatric patients with type 1 diabetes. Advanced technologies, such as continuous glucose monitoring (CGM), intermittently scanned CGM, and sensor-augmented pump therapy with low-glucose suspend system, potentially minimize the occurrence of severe hypoglycemia without worsening overall glycemic control. Hybrid closed-loop system must be the most promising tool for achieving optimal glycemic control with preventing the occurrence of severe hypoglycemia in pediatric patients with type 1 diabetes.

Neonatal hyperglycemia alters the neurochemical profile, dendritic arborization and gene expression in the developing rat hippocampus

Hyperglycemia (blood glucose concentration >150 mg/dL) is common in extremely low gestational age newborns (ELGANs; birth at <28 week gestation). Hyperglycemia increases the risk of brain injury in the neonatal period. The long-term effects are not well understood. In adult rats, hyperglycemia alters hippocampal energy metabolism. The effects of hyperglycemia on the developing hippocampus were studied in rat pups. In Experiment 1, recurrent hyperglycemia of graded severity (moderate hyperglycemia (moderate-HG), mean blood glucose 214.6 ± 11.6 mg/dL; severe hyperglycemia (severe-HG), 338.9 ± 21.7 mg/dL; control, 137.7 ± 2.6 mg/dL) was induced from postnatal day (P) 3 to P12. On P30, the hippocampal neurochemical profile was determined using in vivo ¹ H MR spectroscopy. Dendritic arborization in the hippocampal CA1 region was determined using microtubule-associated protein (MAP)-2 immunohistochemistry. In Experiment 2, continuous hyperglycemia (mean blood glucose 275.3 ± 25.8 mg/dL; control, 142.3 ± 2.6 mg/dL) was induced from P2 to P6 by injecting streptozotocin (STZ) on P2. The mRNA expression of glycogen synthase 1 (Gys1), lactate dehydrogenase (Ldh), glucose transporters 1 (Glut1) and 3 (Glut3) and monocarboxylate transporters 1 (Mct1), 2 (Mct2) and 4 (Mct4) in the hippocampus was determined on P6. In Experiment 1, MRS demonstrated lower lactate concentration and glutamate/glutamine (Glu/Gln) ratio in the severe-HG group, compared with the control group (p < 0.05). Phosphocreatine/creatine ratio was higher in both hyperglycemia groups (p < 0.05). MAP-2 histochemistry demonstrated longer apical segment length, indicating abnormal synaptic efficacy in both hyperglycemia groups (p < 0.05). Experiment 2 showed lower Glut1, Gys1 and Mct4 expression and higher Mct1 expression in the hyperglycemia group, relative to the control group (p < 0.05). These results suggest that hyperglycemia alters substrate transport, lactate homeostasis, dendritogenesis and Glu-Gln cycling in the developing hippocampus. Abnormal neurochemical profile and dendritic structure due to hyperglycemia may partially explain the long-term hippocampus-mediated cognitive deficits in human ELGANs.

Longitudinal assessment of hippocampus structure in children with type 1 diabetes

The extant literature finds that children with type 1 diabetes mellitus (T1D) experience mild cognitive alterations compared to healthy age-matched controls. The neural basis of these cognitive differences is unclear but may relate in part to the effects of dysglycemia on the developing brain. We investigated longitudinal changes in hippocampus volume in young children with early-onset T1D. Structural magnetic resonance imaging data were acquired from 142 children with T1D and 65 age-matched control subjects (4-10 years of age at study entry) at 2 time points, 18 months apart. The effects of diabetes and glycemic exposure on hippocampal volume and growth were examined. Results indicated that although longitudinal hippocampus growth did not differ between children with T1D and healthy control children, slower growth of the hippocampus was associated with both increased exposure to hyperglycemia (interval HbA1c) and greater glycemic variability (MAGE) in T1D. These observations indicate that the current practice of tolerating some hyperglycemia to minimize the risk of hypoglycemia in young children with T1D may not be optimal for the developing brain. Efforts that continue to assess the factors influencing neural and cognitive development in children with T1D will be critical in minimizing the deleterious effects of diabetes.

Psychiatric disorders during early adulthood in those with childhood onset type 1 diabetes: Rates and clinical risk factors from population-based follow-up

AIM

To determine the incidence of and risk factors for psychiatric disorders in early adulthood in patients with childhood onset type 1 diabetes (T1D).

METHODS

In this retrospective-cohort study, we identified a population-based childhood onset T1D cohort and an age and sex matched (5:1) non-diabetic comparison cohort. Data linkage was used to access inpatient hospitalization data, mental health support service data, and mortality data to follow-up both cohorts into early adulthood.

RESULTS

The mean age of T1D diagnosis was 9.5 years (SD 4.1), with a mean age at end of follow-up of 26.4 years (SD 5.2, max 37.7). The diagnosis of any psychiatric disorder was observed for 187 of 1302 (14.3%) in the T1D cohort and 400 of 6422 (6.2%) in the comparison cohort [adjusted hazard ratio (HR) 2.3; 95% CI 1.9, 2.7]. Anxiety, eating, mood, and personality and behaviour disorders were observed at higher rates within the T1D cohort. Comorbid psychiatric disorders were more frequent, at the cohort level, within the T1D cohort (2-3 disorders 3.76% vs 1.56%) and service utilization was higher (15+ contacts 6.8% vs 2.8%); though these differences did not remain when restricted to only those individuals diagnosed during follow-up. A history of poor glycaemic control was associated with an increased risk of anxiety, mood, and 'any' disorder (HR ranging from 1.35 to 1.42 for each 1% increase in mean paediatric HbA1c).

CONCLUSION

Our findings highlight the need for access to mental health support services as part of routine patient care for young adults with T1D, and for better predictive tools to facilitate targeting at-risk patients with early intervention programs.

Effect of recurrent severe hypoglycemia on cognitive performance in adult patients with diabetes: A meta-analysis

The purpose of this study was to investigate the existence and extent of cognitive impairment in adult diabetes mellitus (DM) patients with episodes of recurrent severe hypoglycemia, by using meta-analysis to synthesize data across studies. PubMed, EMBASE and Cochrane library search engines were used to identify studies on cognitive performance in DM patients with recurrent severe hypoglycemia. Random-effects meta-analysis was performed on seven eligible studies using an inverse-variance method. Effect sizes, which are the standardized differences between the experimental group and the control group, were calculated. Of the 853 studies, 7 studies met the inclusion criteria. Compared with control subjects, the adult DM patients with episodes of recurrent severe hypoglycemia demonstrated a significantly lowered performance on memory in both types of DM patients, and poor performance of processing speed in type 2 DM patients. There was no significant difference between adult DM patients with and those without severe hypoglycemia in other cognitive domains such as general intelligence, executive function, processing speed and psychomotor efficiency. Our results seem to confirm the hypothesis that cognitive dysfunction is characterized by worse memory and processing speed in adult DM patients with a history of recurrent severe hypoglycemia, whereas general intelligence, executive function, and psychomotor efficiency are spared.

Incidence of diabetes-related complications in Chinese patients with type 1 diabetes: a population-based longitudinal cohort study in Taiwan

OBJECTIVE

To estimate the incidence densities and cumulative incidence of diabetes-related complications in patients with type 1 diabetes for a maximum of 15-year follow-up. The estimations were further stratified by gender and age at diagnosis (ie, early onset: 0-12 years, late onset:≥13 years).

DESIGN

A population-based retrospective longitudinal cohort study.

SETTING

Taiwan's National Health Insurance medical claims.

PARTICIPANTS

4007 patients newly diagnosed with type 1 diabetes were identified during 1999-2012.

OUTCOME MEASURES

Acute complications included diabetic ketoacidosis (DKA) and hypoglycaemia. Chronic complications were cardiovascular diseases (CVD), retinopathy, neuropathy and nephropathy.

RESULTS

The incidence density of retinopathy was greatest (97.74 per 1000 person-years), followed by those of nephropathy (31.36), neuropathy (23.93) and CVD (4.39). Among acute complications, the incidence density of DKA was greatest (121.11 per 1000 person-years). The cumulative incidences of acute complications after 12 years following diagnosis were estimated to be 52.1%, 36.1% and 4.1% for DKA, outpatient hypoglycaemia and hospitalised hypoglycaemia, respectively. For chronic complications, the cumulative incidence of retinopathy after 12 years following diagnosis was greatest (65.2%), followed by those of nephropathy (30.2%), neuropathy (23.7%) and CVD (4.1%). Females with late-onset diabetes were greatly affected by advanced retinopathy (ie, sight-threatening diabetic retinopathy) and hospitalised hypoglycaemia, whereas those with early-onset diabetes were more vulnerable to DKA. Chronic complications were more commonly seen in late-onset diabetes, whereas early-onset diabetes were most affected by acute complications.

CONCLUSIONS

Ethnic Chinese patients with type 1 diabetes were greatly affected by DKA and retinopathy. The incidence of diabetes-related complications differed by age at diagnosis and sex.

Role of the PI3K/AKT signalling pathway in apoptotic cell death in the cerebral cortex of streptozotocin-induced diabetic rats

Diabetes mellitus is associated with cognitive dysfunction. Numerous previous studies have shown that type 1 diabetes-induced hyperglycaemia causes structural brain damage, such as a decrease in whole-brain grey matter. The impact of diabetes mellitus on the cerebral cortex is poorly understood and requires further clarification. In the present study, diabetes was induced via an intraperitoneal injection of streptozotocin (50 mg/kg). Hematoxylin and eosin (H&E) staining was performed to detect the morphological changes in the cerebral cortex, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) staining was used to detect neuronal apoptosis and western blotting was performed to determine protein expression levels. Nine weeks after the induction of diabetes, the body weight was significantly lower and the blood glucose levels were significantly higher in the diabetic rats than in the control rats (P<0.05). H&E staining revealed nuclear chromatin condensation and cytoplasmic shrinkage in the cerebral cortex of the diabetic rats and TUNEL staining further indicated apoptotic changes in the cerebral cortex of the diabetic rats. The ratio of B-cell lymphoma 2 (Bcl-2) -associated X protein/Bcl-2 and the expression of cytochrome c and activated caspase-3 (cleaved caspase-3) were significantly increased, whereas the ratio of phosphorylated AKT/AKT was significantly decreased in the diabetic rats compared with that in the control rats (P<0.05). Taken together, these results suggested that diabetes mellitus may induce neuronal apoptosis in the cerebral cortex by downregulating AKT phosphorylation.

Association of diabetes mellitus and structural changes in the central nervous system in children and adolescents: a systematic review

Background

The relationship between diabetes and academic performance have been of great interest to researchers during the year to date. Many studies have been conducted to discover this relationship during three recent decades. But, evaluation of the structural changes of brain in the context of diabetes is of paramount importance especially in children and adolescents.

Methods

This study is a systematic review conducted to investigate the structural changes in the central nervous system in children and adolescents living with diabetes. Among about 500 papers published in this area in Pubmed and SCOPUS, 13 articles in the field of assessing structural changes in the central nervous system in children and adolescents with diabetes mellitus were entered into the evaluation process.

Results

As can be seen in these studies, a huge proportion of structures of the central nervous system have been affected by diabetes that include different areas of gray and white matters. In the majority of these studies, it has become clear that high glycemic changes, especially recurrent hyperglycemic attacks are very seriously associated with structural changes in the brain.

Conclusion

It seems the findings of this review can positively aid other researchers to develop medical guidelines to prevent or resolve the brain changes in central nervous structure and consequently cognitive impairments in children and adolescents.

Bipolar Disorder Type 1 in a 17-Year-Old Girl with Wolfram Syndrome

OBJECTIVE

Wolfram syndrome (WS, MIM 222300) is a rare autosomal, recessive neurodegenerative disorder associated with mutations in WFS1, a gene that has been associated with bipolar disorder (BD). WS, characterized by the association of juvenile-onset diabetes mellitus (DM) and bilateral progressive optic atrophy (BPOA), encompasses several other clinical features, including cognitive impairments and psychiatric disorders. Detailed data on the psychiatric phenotype are still scarce, and how WS relates to BD is still unknown.

METHOD

A 17-year-old girl with WS was hospitalized for early-onset BD. A multidisciplinary and developmental assessment was carried out to control mood symptoms and address how BD could be related to WS.

RESULTS

Besides DM and BPOA, the patient had several risk factors for BD/mood disorders as follows: (1) a history of abuse and maltreatment; (2) a history of specific language disorder and borderline intelligence associated with academic failure; and (3) a comorbid hypothyroidism. Treatment encompassed all aspects of the adolescent's conditions, such as the use of mood stabilizers, addressing psychosocial and scholastic problems, and treating hypothyroid dysfunction.

CONCLUSION

Given the complexity of WS, this case suggests that the possible association between WS and BD should not only be merely limited to a possible statistical association with WFS1 polymorphism but also to developmental, cognitive, and endocrine risk factors for BD.

Variations in Brain Volume and Growth in Young Children With Type 1 Diabetes

Early-onset type 1 diabetes may affect the developing brain during a critical window of rapid brain maturation. Structural MRI was performed on 141 children with diabetes (4-10 years of age at study entry) and 69 age-matched control subjects at two time points spaced 18 months apart. For the children with diabetes, the mean (±SD) HbA1c level was 7.9 ± 0.9% (63 ± 9.8 mmol/mol) at both time points. Relative to control subjects, children with diabetes had significantly less growth of cortical gray matter volume and cortical surface area and significantly less growth of white matter volume throughout the cortex and cerebellum. For the population with diabetes, the change in the blood glucose level at the time of scan across longitudinal time points was negatively correlated with the change in gray and white matter volumes, suggesting that fluctuating glucose levels in children with diabetes may be associated with corresponding fluctuations in brain volume. In addition, measures of hyperglycemia and glycemic variation were significantly negatively correlated with the development of surface curvature. These results demonstrate that early-onset type 1 diabetes has widespread effects on the growth of gray and white matter in children whose blood glucose levels are well within the current treatment guidelines for the management of diabetes.

Mechanisms of hypoglycemia unawareness and implications in diabetic patients

Hypoglycemia unawareness (HU) is defined at the onset of neuroglycopenia before the appearance of autonomic warning symptoms. It is a major limitation to achieving tight diabetes and reduced quality of life. HU occurs in approximately 40% of people with type 1 diabetes mellitus (T1DM) and with less frequency in T2DM. Though the aetiology of HU is multifactorial, possible mechanisms include chronic exposure to low blood glucose, antecedent hypoglycaemia, recurrent severe hypoglycaemia and the failure of counter-regulatory hormones. Clinically it manifests as the inability to recognise impeding hypoglycaemia by symptoms, but the mechanisms and mediators remain largely unknown. Prevention and management of HU is complex, and can only be achieved by a multifactorial intervention of clinical care and structured patient education by the diabetes team. Less know regarding the impact of medications on the development or recognition of this condition in patients with diabetes. Several medications are thought to worsen or promote HU, whereas others may have an attenuating effect on the problem. This article reviews recent advances in how the brain senses and responds to hypoglycaemia, novel mechanisms by which people with insulin-treated diabetes develop HU and impaired counter-regulatory responses. The consequences that HU has on the person with diabetes and their family are also described. Finally, it examines the evidence for prevention and treatment of HU, and summarizes the effects of medications that may influence it.

Longitudinal assessment of neuroanatomical and cognitive differences in young children with type 1 diabetes: association with hyperglycemia

Significant regional differences in gray and white matter volume and subtle cognitive differences between young diabetic and nondiabetic children have been observed. Here, we assessed whether these differences change over time and the relation with dysglycemia. Children ages 4 to <10 years with (n = 144) and without (n = 72) type 1 diabetes (T1D) had high-resolution structural MRI and comprehensive neurocognitive tests at baseline and 18 months and continuous glucose monitoring and HbA1c performed quarterly for 18 months. There were no differences in cognitive and executive function scores between groups at 18 months. However, children with diabetes had slower total gray and white matter growth than control subjects. Gray matter regions (left precuneus, right temporal, frontal, and parietal lobes and right medial-frontal cortex) showed lesser growth in diabetes, as did white matter areas (splenium of the corpus callosum, bilateral superior-parietal lobe, bilateral anterior forceps, and inferior-frontal fasciculus). These changes were associated with higher cumulative hyperglycemia and glucose variability but not with hypoglycemia. Young children with T1D have significant differences in total and regional gray and white matter growth in brain regions involved in complex sensorimotor processing and cognition compared with age-matched control subjects over 18 months, suggesting that chronic hyperglycemia may be detrimental to the developing brain.

Risk factors for decline in IQ in youth with type 1 diabetes over the 12 years from diagnosis/illness onset

OBJECTIVE

This study examined illness-related change in intelligence quotient (IQ) in a cohort of youth with type 1 diabetes studied prospectively from disease onset in childhood to follow-up 12 years later in late adolescence/early adulthood.

RESEARCH DESIGN AND METHODS

Participants included type 1 diabetes patients (n = 95; mean age at follow-up 21.3 years) and healthy control participants (HCs; n = 67; mean age at follow-up 21.0 years) from a cohort followed prospectively. Measures included Wechsler Preschool and Primary Scale of Intelligence-Revised, Wechsler Intelligence Scale for Children-Revised, and Wechsler Abbreviated Scale of Intelligence and prospective collection of data on metabolic control history.

RESULTS

Young people with type 1 diabetes showed greater decline in verbal IQ (VIQ) and full-scale IQ (FSIQ), but not performance IQ (PIQ), than HCs. Within the diabetes group, a younger age at diabetes onset was associated with a decline in PIQ and FSIQ (P ≤ 0.001). A history of hypoglycemic seizures was associated with a decline in VIQ (P = 0.002). Long-term metabolic control was not associated with changes in IQ. Interaction terms were not significant, suggesting no moderating effect of one diabetes-related variable over another.

CONCLUSIONS

The presence of diabetes may negatively influence some aspects of IQ over time. Specific illness risk factors, such as an earlier age of disease onset and a history of hypoglycemic seizures, appear to put the young person at greater risk. Academic progress of children identified as at risk should be monitored and educational supports provided if necessary.

Neurocognitive outcomes in pediatric diabetes: a developmental perspective

The impact of diabetes on the developing brain is well-accepted. Effects on neurocognitive functioning are moderate but have larger functional implications, especially when considered through a developmental lens. Pathophysiological factors such as severe hypoglycemia and chronic hyperglycemia can alter developmental trajectories in early childhood and perhaps at later periods. In this paper, we selectively review neurocognitive outcomes in pediatric diabetes (largely type 1), integrating recent research from developmental neuroscience and neuroimaging. We examine the effects of diabetes at different stages and place findings within a neurodevelopmental diathesis/stress framework. Early-onset diabetes is associated with specific effects on memory and more global cognitive late-effects, but less is known about cognitive outcomes of diabetes in later childhood and in adolescence, a time of increased neurobehavioral vulnerability that has received relatively limited empirical attention. Studies are also needed to better elucidate risk and protective factors that may moderate neurodevelopmental outcomes in youth with diabetes.

Adolescents with Type 1 diabetes mellitus experience psychosensorial symptoms during hypoglycaemia

AIM

To describe mood and psychosensorial symptoms of hypoglycaemia in adolescents with Type 1 diabetes mellitus in two countries with different cultures, Turkey and the USA.

METHODS

We developed a 68-item questionnaire assessing physical, behavioural, mood and psychosensorial symptom frequency and ratings ['good', 'bad', or 'both' (sometimes good, sometimes bad)]. Adolescents with Type 1 diabetes were recruited from paediatric diabetes clinics at the University of North Carolina at Chapel Hill in the USA and Kocaeli University in Turkey. The percentages of participants at each clinic who endorsed individual symptoms, symptom categories and symptom ratings were calculated and compared.

RESULTS

Cronbach's α values were > 0.7 for each real symptom category. No symptom items were excluded from the questionnaire analysis based on item-total correlation results which were all > 0.2. Data were collected from 132 participants (69 from University of North Carolina, 63 from Kocaeli University, 54% male). The mean (SD) age of the participants was 14.9 (1.9) years, HbA1c level was 8.7 (1.8) % and duration of Type 1 diabetes was 5.8 (3.7) years. On average, each physical symptom was experienced by 65.2% of participants, each behavioural symptom by 46.5%, each mood symptom by 42.8%, and each psychosensorial symptom by 48.9%. On average, each physical, behavioral, mood and psychosensorial symptom was rated as 'good' or 'both' by 23.0, 29.1, 36.9 and 37.2% of participants, respectively. There were no symptom differences between the groups in each country.

CONCLUSIONS

In addition to the classic physical symptoms experienced during hypoglycaemia, adolescents with Type 1 diabetes report psychosensorial, mood and behavioral symptoms, and some describe them as positive experiences. Symptom experiences were similar in these two countries with different cultures.

Aspartame Administration and Insulin Treatment Altered Brain Levels of CYP2E1 and CYP3A2 in Streptozotocin-Induced Diabetic Rats

This study demonstrates that aspartame consumption and insulin treatment in a juvenile diabetic rat model leads to increase in cytochrome P450 (CYP) 2E1 and CYP3A2 isozymes in brain. Diabetes mellitus was induced in postweaned 21-day-old Wistar male rat by streptozotocin. Animals were randomly assigned to one of the following groups: untreated control, diabetic (D), D-insulin, D-aspartame, or the D-insulin + aspartame-treated group. Brain and liver tissue samples were used to analyze the activity of CYP2E1 and CYP3A2 and protein levels. Our results indicate that combined treatment with insulin and aspartame in juvenile diabetic rats significantly induced CYP2E1 in the cerebrum and cerebellum without modifying it in the liver, while CYP3A2 protein activity increased both in the brain and in the liver. The induction of CYP2E1 in the brain could have important in situ toxicological effects, given that this CYP isoform is capable of bioactivating various toxic substances. Additionally, CYP3A2 induction in the liver and brain could be considered a decisive factor in the variation of drug response and toxicity.

Hippocampal Volume in Type 1 Diabetes

The hippocampus plays an important role in human memory and is known to be vulnerable to extreme hyperglycaemia and hypoglycaemia in animal models of type 1 diabetes. Within humans with type 1 diabetes, exposure to glycaemic extremes has been associated with alterations in hippocampal structure and in memory function, but results are inconsistent. It has been hypothesised that the effects of hypoglycaemia and hyperglycaemia on the hippocampus may depend on when during neurodevelopment these extremes occur, possibly explaining some of these inconsistencies. However, data addressing this concept are limited. We review here the existing literature on this complex topic and suggest future avenues of required research.

A randomized trial comparing the rate of hypoglycemia--assessed using continuous glucose monitoring--in 125 preschool children with type 1 diabetes treated with insulin glargine or NPH insulin (the PRESCHOOL study)

BACKGROUND

Avoidance of hypoglycemia is a key consideration in treating young children with type 1 diabetes (T1DM).

KEY OBJECTIVE

To evaluate hypoglycemia with insulin glargine vs. neutral protamine Hagedorn (NPH) insulin in young children, using continuous glucose monitoring (CGM).

SUBJECTS

Children of 1 to <6 yr treated with once-daily glargine vs. once- or twice-daily NPH, with bolus insulin lispro/regular human insulin provided to all.

METHODS

Twenty-four week, multicenter, randomized, open-label study. Primary endpoint was event rate of composite hypoglycemia [symptomatic hypoglycemia, low CGM excursions (<3.9 mmol/L) or low fingerstick blood glucose (FSBG; <3.9 mmol/L)]. Noninferiority of glargine vs. NPH was assessed for the primary endpoint.

RESULTS

One hundred and twenty-five patients (mean age, 4.2 yr) were randomized to treatment (glargine, n = 61; NPH, n = 64). At baseline, mean HbA1c was 8.0 and 8.2% with glargine and NPH, respectively. Composite hypoglycemia episodes/100 patient-yr was 1.93 for glargine and 1.69 for NPH; glargine noninferiority was not met. Events/100 patient-yr of symptomatic hypoglycemia were 0.26 for glargine vs. 0.33 for NPH; low CGM excursions 0.75 vs. 0.72; and low FSBG 1.93 vs.1.68. There was a slight difference in between-group severe/nocturnal/severe nocturnal hypoglycemia and glycemic control. All glargine-treated patients received once-daily injections; on most study days NPH-treated patients received twice-daily injections.

CONCLUSIONS

While glargine noninferiority was not achieved, in young children with T1DM, there was a slight difference in hypoglycemia outcomes and glycemic control between glargine and NPH. Once-daily glargine may therefore be a feasible alternative basal insulin in young populations, in whom administering injections can be problematic.

Glycemic extremes in youth with T1DM: the structural and functional integrity of the developing brain

The adult brain accounts for a disproportionally large percentage of the body’s total energy consumption (1). However, during brain development,energy demand is even higher, reaching the adult rate by age 2 and increasing to nearly twice the adult rate by age 10, followed by gradual reduction toward adult levels in the next decade (1,2). The dramatic changes in brain metabolism occurring over the first two decades of life coincide with the initial proliferation and then pruning of synapses to adult levels.The brain derives its energy almost exclusively from glucose and is largely driven by neuronal signaling, biosynthesis, and neuroprotection (3–6).Glucose homeostasis in the body is tightly regulated by a series of hormones and physiologic responses. As a result, hypoglycemia and hyperglycemia are rare occurrences in normal individuals, but they occur commonly inpatients with type 1 diabetes mellitus (T1DM) due to a dysfunction of peripheral glucose-insulin-glucagon responses and non-physiologic doses of exogenous insulin, which imperfectly mimic normal physiology. These extremes can occur more frequently in children and adolescents with T1DM due to the inadequacies of insulin replacement therapy, events leading to the diagnosis [prolonged untreated hyperglycemia and diabetic ketoacidosis (DKA)], and to behavioral factors interfering with optimal treatment. When faced with fluctuations in glucose supply the metabolism of the body and brain change dramatically, largely to conserve resources and, at a cost to other organs, to preserve brain function (7). However,if the normal physiological mechanisms that prevent these severe glucose fluctuations and maintain homeostasis are impaired, neuronal function and potentially viability can be affected (8–11).

Frontal gray matter atrophy in middle aged adults with type 1 diabetes is independent of cardiovascular risk factors and diabetes complications

AIMS

To determine if regional gray matter volume (GMV) differences in middle-aged adults with and without type-1 diabetes (T1D) are localized in areas most vulnerable to aging, e.g. fronto-subcortical networks; and if these differences are explained by cardiovascular risk factors and diabetes complications.

METHODS

Regional GMV was computed using 3T MRI of 104 adults with a childhood onset of T1D (mean age: 49±7 and duration: 41±6years) and 151 adults without diabetes (mean age: 40±6). A Bonferroni threshold (n=45, p≤0.001) was applied to account for multiple between-group comparisons and analyses were repeated in an age- and gender-matched subset of participants with T1D and controls (n=44 in each group, mean age [SD] and range: 44.0, [4.3], 17.4 and 44.6 [4.3], 17.0, respectively).

RESULTS

Compared to controls, T1D patients had smaller GMV in the frontal lobe (6% to 19% smaller) and adjacent supramarginal and postcentral gyri (8% to 13% smaller). Between-group differences were independent of age, waist circumference, systolic blood pressure, fasting total cholesterol and smoking status and were similar in sensitivity analyses restricted to age- and gender-matched participants. Associations between GMV and diabetes complications were not significant.

CONCLUSIONS

These findings extend the notion of accelerated brain aging in T1D to middle-aged adults. The pathophysiology of frontal gray matter atrophy and its impact on future development of disability and dementia need further study, especially as middle-aged T1D patients progress to older age.

A multicenter observational safety study in Swedish children and adolescents using insulin detemir for the treatment of type 1 diabetes

This 26-wk observational study in children and adolescents with type 1 diabetes (T1D) in Sweden investigated the safety and efficacy of insulin detemir (IDet) in newly diagnosed (ND) patients and those with established diabetes (ED) switching to IDet. A total of 159 patients initiated IDet as part of basal-bolus therapy, 59 in the ND stratum (mean age 9.7 yr) and 97 in the ED stratum (mean age 12.5 yr). The primary outcome measure was the incidence of severe adverse drug reactions; just one major hypoglycemic event occurred in a patient in the ND stratum during the study and one patient was withdrawn due to injection-site reactions. All other events were classified as mild. In the ED stratum, there was a reduction in hypoglycemic events in the 4 wk prior to study end from baseline (mean reduction of 2.46 events, not significant) and a significant reduction in nocturnal hypoglycemia (mean reduction of 2.24 events, p = 0.0078). Glycemic control improved in the ND stratum as expected and, in the ED stratum, there was no significant change in HbA1c from baseline (mean reduction of -0.45%). At study end, mean daily IDet doses were 0.39 U/kg (ND) and 0.54 U/kg (ED). Weight increased by 5.7 and 2.0 kg in the ND and ED strata, respectively, and was within the normal limits for growing children. IDet provided good glycemic control and was well tolerated, with a reduced risk of nocturnal hypoglycemia in a heterogeneous cohort of children and adolescents with T1D.

Role of neuronal apoptosis in volumetric change of hippocampus in diabetes mellitus type 1: a predictive model

Background. Neuronal apoptosis is the major cause of diabetes central neuropathy, but its role in volumetric changes of hippocampus has not been clarified. The aims of this study were to assess the role of apoptosis in volumetric changes of dentate gyrus (DG) and CA3 region of hippocampus and to determine a reference point in which these neuropathological changes reach a meaningful level. Methods and Materials. Diabetes was induced in male Wistar rats (N = 10) by streptozotocin (60 mg/kg). Six weeks after diabetes, verification animals were divided into four groups as follows: diabetic treated with insulin (3–5 U), diabetic treated with vitamin C (80 mg/kg), and diabetic and control groups. At the end of 8 weeks, numerical density of apoptotic neurons and volume of dentate gyrus and CA3 were calculated by stereological methods. Results. The number of apoptotic neurons in DG and CA3 in diabetic group showed significant level of difference in comparison with the control (P < 0.001). The volume of DG and CA3 in diabetic and vitamin C showed significant level of difference compared with control (P < 0.001). Conclusion. Our results suggest that DG and CA3 volume reduction begins and progresses independently of neuronal loss.

Neuronal damage and cognitive impairment associated with hypoglycemia: An integrated view

The aim of the present review is to offer a current perspective about the consequences of hypoglycemia and its impact on the diabetic disorder due to the increasing incidence of diabetes around the world. The main consequence of insulin treatment in type 1 diabetic patients is the occurrence of repetitive periods of hypoglycemia and even episodes of severe hypoglycemia leading to coma. In the latter, selective neuronal death is observed in brain vulnerable regions both in humans and animal models, such as the cortex and the hippocampus. Cognitive damage subsequent to hypoglycemic coma has been associated with neuronal death in the hippocampus. The mechanisms implicated in selective damage are not completely understood but many factors have been identified including excitotoxicity, oxidative stress, zinc release, PARP-1 activation and mitochondrial dysfunction. Importantly, the diabetic condition aggravates neuronal damage and cognitive failure induced by hypoglycemia. In the absence of coma prolonged and severe hypoglycemia leads to increased oxidative stress and discrete neuronal death mainly in the cerebral cortex. The mechanisms responsible for cell damage in this condition are still unknown. Recurrent moderate hypoglycemia is far more common in diabetic patients than severe hypoglycemia and currently important efforts are being done in order to elucidate the relationship between cognitive deficits and recurrent hypoglycemia in diabetics. Human studies suggest impaired performance mainly in memory and attention tasks in healthy and diabetic individuals under the hypoglycemic condition. Only scarce neuronal death has been observed under moderate repetitive hypoglycemia but studies suggest that impaired hippocampal synaptic function might be one of the causes of cognitive failure. Recent studies have also implicated altered mitochondrial function and mitochondrial oxidative stress.

White matter microstructural integrity in youth with type 1 diabetes

Decreased white and gray matter volumes have been reported in youth with type 1 diabetes mellitus (T1DM), but the effects of hyperglycemia on white matter integrity have not been quantitatively assessed during brain development. We performed diffusion tensor imaging, using two complimentary approaches--region-of-interest and voxelwise tract-based spatial statistics--to quantify white matter integrity in a large retrospective study of T1DM youth and control participants. Exposure to chronic hyperglycemia, severe hyperglycemic episodes, and severe hypoglycemia, as defined in the Diabetes Control and Complications Trial (DCCT), were estimated through medical records review, HbA(1c) levels, and interview of parents and youth. We found lower fractional anisotropy in the superior parietal lobule and reduced mean diffusivity in the thalamus in the T1DM group. A history of three or more severe hyperglycemic episodes was associated with reduced anisotropy and increased diffusivity in the superior parietal lobule and increased diffusivity in the hippocampus. These results add microstructural integrity of white matter to the range of structural brain alterations seen in T1DM youth and suggest vulnerability of the superior parietal lobule, hippocampus, and thalamus to glycemic extremes during brain development. Longitudinal analyses will be necessary to determine how these alterations change with age or additional glycemic exposure.

The importance of hypoglycemia in diabetic patients

Hypoglycemia is one of the most important complications of diabetes treatment. The risk of severe hypoglycemia is higher in elderly patients, those having comorbidities such as vascular disease or renal failure, pregnant women and in children with type 1diabetes. Moreover, in type 2 diabetes, progressive insulin deficiency, longer duration of diabetes, and tight glycemic control increase the risk of hypoglycemia as much as type 1 diabetes.Episodes hypoglycemia may lead to impairment of counter-regulatory system, with the potential of development of hypoglycemia unawareness. So, hypoglycemia may increase the vascular events even death in addition to other possible detrimental effects. Glycemic control should be individualized based on patient characteristics with some degree of safety. Recognition of hypoglycemia risk factors, blood glucose monitoring, selection of appropriate regimens and educational programs for healthcare professionals and patients with diabetes are the major issues to maintain good glycemic control, minimize the risk of hypoglycemia, and prevent long- term complications.

Prospectively determined impact of type 1 diabetes on brain volume during development

OBJECTIVE

The impact of type 1 diabetes mellitus (T1DM) on the developing central nervous system is not well understood. Cross-sectional, retrospective studies suggest that exposure to glycemic extremes during development is harmful to brain structure in youth with T1DM. However, these studies cannot identify brain regions that change differentially over time depending on the degree of exposure to glycemic extremes.

RESEARCH DESIGN AND METHODS

We performed a longitudinal, prospective structural neuroimaging study of youth with T1DM (n = 75; mean age = 12.5 years) and their nondiabetic siblings (n = 25; mean age = 12.5 years). Each participant was scanned twice, separated by 2 years. Blood glucose control measurements (HbA(1c), glucose meter results, and reports of severe hypoglycemia) were acquired during the 2-year follow-up. Sophisticated image registration algorithms were performed, followed by whole brain and voxel-wise statistical analyses of the change in gray and white matter volume, controlling for age, sex, and age of diabetes onset.

RESULTS

The T1DM and nondiabetic control (NDC) sibling groups did not differ in whole brain or voxel-wise change over the 2-year follow-up. However, within the T1DM group, participants with more hyperglycemia had a greater decrease in whole brain gray matter compared with those with less hyperglycemia (P < 0.05). Participants who experienced severe hypoglycemia had greater decreases in occipital/parietal white matter volume compared with those with no severe hypoglycemia (P < 0.05) and compared with the NDC sibling group (P < 0.05).

CONCLUSIONS

These results demonstrate that within diabetes, exposure to hyperglycemia and severe hypoglycemia may result in subtle deviation from normal developmental trajectories of the brain.

The effect of recurrent severe hypoglycemia on cognitive performance in children with type 1 diabetes: a meta-analysis

The purpose of this study was to investigate the existence and extent of cognitive impairment in type 1 diabetic children with episodes of recurrent severe hypoglycemia, using meta-analysis to synthesize data across studies. The meta-analysis sample included: 441 children with diabetes and recurrent severe hypoglycemia, 560 children with diabetes and without recurrent severe hypoglycemia. Overall, children with type 1 diabetes and recurrent severe hypoglycemia had slightly lower performance than diabetic children without severe hypoglycemia, only in some cognitive domains: intelligence, memory, learning, and verbal fluency/language. Greater impairment was found in memory and learning. No impairment was found for motor speed. Our results seem to confirm the hypothesis that recurrent severe hypoglycemia has a selective negative effect on the children's cognitive functions. However, these results must be considered with caution taking into account factors such as small sample sizes, the different definitions of severe hypoglycemia, and the variety of neuropsychological tests used.

Neurocognitive outcomes in young adults with early-onset type 1 diabetes: a prospective follow-up study

OBJECTIVE

The aim of this study was to reexamine the neurocognitive function of a cohort of young adults with early-onset type 1 diabetes and compare their cognitive function to a matched control group. We also examined whether cognitive function was related to prospectively obtained severe hypoglycemia history, long-term glycemic control, or severe diabetic ketoacidosis.

RESEARCH DESIGN AND METHODS

Testing included Wechsler Intelligence Scale for Children and Adults, Wechsler Memory Scale, Cattell Culture Fair Intelligence Test (CCFIT), Wisconsin Card Sorting Test (WCST), youth and adult self-report, and Beck Depression Inventory. We tested 34 control subjects (mean ± SE, age 19.5 ± 0.5 years) and 33 type 1 diabetic subjects (age 19.3 ± 0.5 years, age at type 1 diabetes onset 3.3 ± 0.3 years, A1C from diagnosis 8.7 ± 0.1%, and diabetes duration 16.0 ± 0.5 years).

RESULTS

There was no difference in full-scale IQ scores in type 1 diabetic and control subjects (100.7 ± 2.0 vs. 102.5 ± 1.4). There was no difference between groups in memory subtests or in reporting of emotional and behavioral difficulties. The type 1 diabetes group scored lower on the CCFIT for fluid intelligence compared with control subjects (P = 0.028) and also scored lower on WCST with more perseverative errors (P = 0.002) and fewer categories completed (P = 0.022).

CONCLUSIONS

These data suggest no difference in general intellectual ability, memory, and emotional difficulties in our cohort of young adults with early-onset type 1 diabetes compared with control subjects and no deterioration over time. There were, however, findings to suggest subtle changes leading to poorer performance on complex tasks of executive function.

Type 1 diabetes mellitus and major depressive disorder: evidence for a biological link

AIMS/HYPOTHESIS

A growing body of research suggests that the prevalence of major depressive disorder (MDD) in children and youth with type 1 diabetes mellitus is significantly higher than that of youth without type 1 diabetes and is associated with increased illness severity. The objective of this article is to review the current literature on the pathophysiology of these two common diseases with respect to potential areas of overlapping biological dysfunction.

METHODS

A search of English language articles published between 1966 and 2010 was conducted and augmented with manual review of reference lists from the identified publications.

RESULTS

The evidence suggests plausible mechanisms whereby a biological relationship between type 1 diabetes and MDD may exist. These include the effects of circulating cytokines associated with autoimmune diabetes, the direct impact of insulin deficiency on neurogenesis/neurotransmitter metabolism, the effects of the chronic hyperglycaemic state, occurrence of iatrogenic hypoglycaemia and the impact of basal hyperactivity of the hypothalamic-pituitary-adrenal axis.

CONCLUSIONS/INTERPRETATION

Shared biological vulnerabilities may be implicated in the comorbidity of type 1 diabetes and MDD. Further research is warranted to determine the magnitude of associations and confirm their observation in clinical populations.

The feasibility of detecting neuropsychologic and neuroanatomic effects of type 1 diabetes in young children

OBJECTIVE

To determine if frequent exposures to hypoglycemia and hyperglycemia during early childhood lead to neurocognitive deficits and changes in brain anatomy.

RESEARCH DESIGN AND METHODS

In this feasibility, cross-sectional study, young children, aged 3 to 10 years, with type 1 diabetes and age- and sex-matched healthy control (HC) subjects completed neuropsychologic (NP) testing and magnetic resonance imaging (MRI) scans of the brain.

RESULTS

NP testing and MRI scanning was successfully completed in 98% of the type 1 diabetic and 93% of the HC children. A significant negative relationship between HbA1c and Wechsler Intelligence Scale for Children (WISC) verbal comprehension was observed. WISC index scores were significantly reduced in type 1 diabetic subjects who had experienced seizures. White matter volume did not show the expected increase with age in children with type 1 diabetes compared with HC children (diagnosis by age interaction, P=0.005). A similar trend was detected for hippocampal volume. Children with type 1 diabetes who had experienced seizures showed significantly reduced gray matter and white matter volumes relative to children with type 1 diabetes who had not experienced seizures.

CONCLUSIONS

It is feasible to perform MRI and NP testing in young children with type 1 diabetes. Further, early signs of neuroanatomic variation may be present in this population. Larger cross-sectional and longitudinal studies of neurocognitive function and neuroanatomy are needed to define the effect of type 1 diabetes on the developing brain.

Encephalopathies: the emerging diabetic complications

Diabetic encephalopathies are now accepted complications of diabetes. They appear to differ in type 1 and type 2 diabetes as to underlying mechanisms and the nature of resulting cognitive deficits. The increased incidence of Alzheimer's disease in type 2 diabetes is associated with insulin resistance, hyperinsulinemia and hyperglycemia, and commonly accompanying attributes such as hypercholesterolemia, hypertension and obesity. The relevance of these disorders as to the emergence of dementia and Alzheimer's disease is discussed based on epidemiological studies. The pathobiology of accumulation of β-amyloid and tau the hallmarks of Alzheimer's disease are discussed based on experimental data. Type 1 diabetic encephalopathy is likely to increase as a result of the global increase in the incidence of type 1 diabetes and its occurrence in increasingly younger patients. Alzheimer-like changes and dementia are not prominently increased in type 1 diabetes. Instead, the type 1 diabetic encephalopathy involves learning abilities, intelligence development and memory retrieval resulting in impaired school and professional performances. The major underlying component here appears to be insulin deficiency with downstream effects on the expression of neurotrophic factors, neurotransmitters, oxidative and apoptotic stressors resulting in defects in neuronal integrity, connectivity and loss commonly occurring in the still developing brain. Recent experimental data emphasize the role of impaired central insulin action and provide information as to potential therapies. Therefore, the underlying mechanisms resulting in diabetic encephalopathies are complex and appear to differ between the two types of diabetes. Major headway has been made in our understanding of their pathobiology; however, many questions remain to be clarified. In view of the increasing incidence of both type 1 and type 2 diabetes, intensified investigations are called for to expand our understanding of these complications and to find therapeutic means by which these disastrous consequences can be prevented and modified.