Effects of hyperglycemia and effects of ketosis on cerebral perfusion, cerebral water distribution, and cerebral metabolism

The impact of early-life exercise on CREB-signaling pathway and hippocampus neuroplasticity in diabetic adult male rats; the study of developmental model

BACKGROUND

Childhood exercise enhances brain structure, while diabetes detrimentally affects it. This study examines early-life exercise's influence on adult diabetic rats' memory and neuroplasticity.

METHODS

Male Wistar pups were divided into Control, Diabetes, Exercise Training, and Diabetes exercise groups. Diabetes was induced on day 23 with Alloxan (200 mg/kg). A 3-week regimen included aerobic and resistance training thrice weekly. The aerobic intensity was 70%, and resistance varied from 50% to 100% of the maximal carrying capacity (MCC). Following the last training sessions, spatial memory and retrieval tests were performed in infancy, childhood, and emerging adulthood using the Morris Water Maze test (MWM). The hippocampus was excised to measure protein and gene expression of brain-derived neurotrophic factor (BDNF), calmodulin-dependent protein kinase (CAMKII), N-methyl-D-aspartate receptors (NMDAR), and cAMP-response element-binding protein (CREB) by western blotting and reverse transcription-polymerase-chain reaction (RT-PCR) methods. Blood samples were collected during each developmental stage to measure glucose levels, at the study's conclusion, to assess Interleukin-1β levels using the ELISA method. The Nissel staining assessed dead hippocampal cells in CA1.

RESULTS

Post-natal exercise improved spatial memory (p < 0.05) and glucose levels (p < 0.05) in diabetic rats during adolescence and emerging adulthood. Despite reduced mRNA expression (NMDAR 40%, BDNF 62%, CREB 43%, CAMKII 66%), diabetic rats, by study end, showed increased BDNF, NMDARR, CAMKII, CREB protein/gene expression (p < 0.05) in emerging adulthood for both training groups.

CONCLUSION

Early-life exercise influenced hippocampal BDNF/NMDAR-CAMKII/CREB pathways in a diabetic rat model, highlighting post-natal exercise's role in neuroplasticity memory enhancement and improved glucose level.

Reversible global hypoperfusion in an adult patient with a mixed diabetic ketoacidosis/hyperglycemic hyperosmolar coma: A case report

Diabetic ketoacidosis is a severe complication of diabetes mellitus. We report a case of global hypoperfusion in an elderly patient on CT, with complete resolution shown on early MRI follow‐up. Metabolic causes have always to be included in the differential diagnosis of diffuse hypoperfusion in the appropriate clinical setting.

The Impact of Hypo- and Hyperglycemia on Cognition and Brain Development in Young Children with Type 1 Diabetes

Human and experimental animal data suggest both hyperglycemia and hypoglycemia can lead to altered brain structure and neurocognitive function in type 1 diabetes (T1D). Young children with T1D are prone to extreme fluctuations in glucose levels. The overlap of these potential dysglycemic insults to the brain during the time of most active brain and cognitive development may cause cellular and structural injuries that appear to persist into adult life. Brain structure and cognition in persons with T1D are influenced by age of onset, exposure to glycemic extremes such as severe hypoglycemic episodes, history of diabetic ketoacidosis, persistent hyperglycemia, and glucose variability. Studies using brain imaging techniques have shown brain changes that appear to be influenced by metabolic abnormalities characteristic of diabetes, changes apparent at diagnosis and persistent throughout adulthood. Some evidence suggests that brain injury might also directly contribute to psychological and mental health outcomes. Neurocognitive deficits manifest across multiple cognitive domains. Moreover, impaired executive function and mental health can affect patients' adherence to treatment. This review summarizes the current data on the impact of glycemic extremes on brain structure and cognitive function in youth with T1D and the use of new diabetes technologies that may reduce these complications.

Ketoacidosis in new-onset type 1 diabetes: did the severity increase during the COVID-19 pandemic?

OBJECTIVES

Since the beginning of the COVID-19 pandemic, there has been a consistent decrease in the number of admissions to the emergency department, leading to a delay in the diagnosis of several pathologies. The time from onset of symptoms to the diagnosis of Type 1 diabetes is highly variable. This treatment delay can lead to the appearance of ketoacidosis.

METHODS

Retrospective study of inaugural Type 1 diabetes cases, from March 2016 to March 2021. The pandemic group was considered between March 2020 to March 2021, and the remaining period was considered as pre-pandemic. Clinical variables were analysed: duration of symptoms, weight loss and value of ketonemia and glycated haemoglobin on admission. The mean differences were considered statistically significant at p<0.05.

RESULTS

103 inaugural episodes of Type 1 diabetes were registered. The pandemic group had a lower mean age when compared to pre-pandemic group, and 51.7% of the episodes had ketoacidosis with a higher relative risk of ketoacidosis and severe ketoacidosis, when compared the pandemic with pre-pandemic group, there was a longer symptom evolution time (34 vs. 20 days), greater weight loss occurred (9.5% vs. 6.3%), the pH and HCO₃ ^- values were lower (7.30 vs. 7.36 and 16.43 vs. 20.71 mmol/L respectively) and ketonemia was higher (5.9 vs. 2.3 mmol/L).

CONCLUSIONS

The COVID-19 pandemic caused a delay in the diagnosis of Type 1 diabetes, greater length of disease, greater weight loss, higher ketonemia and lower pH and HCO₃ ^-. There was greater ketoacidosis relative risk in pandemic group when compared to pre-pandemic group.

Hyperglycemia associated with acute brain injury in neonatal encephalopathy

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Cohort study of neonatal encephalopathy using continuous glucose monitoring.

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Higher glucose on day 1 associated with widespread changes in brain microstructure.

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Lower glucose not associated with brain microstructural changes.

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No changes in MR spectroscopy found related to higher or lower glucose.

Objective

To identify how alterations in glucose levels are associated with regional brain injury in neonatal encephalopathy.

Methods

This was a prospective cohort study of 102 newborns with neonatal encephalopathy, with continuous glucose monitoring for 72 h. 97 (95%) completed 72 h of therapeutic hypothermia. Brain imaging around day 5 of life included diffusion tensor imaging and MR spectroscopy. Regions of interest were placed for both DTI and MR spectroscopy, and tractography of the optic radiation and corticospinal tract were evaluated. Linear regression models related each MR metric with minimum and maximum glucose values during each day of life, adjusting for 5-minute Apgar scores and umbilical artery pH.

Results

Higher maximum glucose levels on the first day of life were associated with widespread changes in mean diffusivity in the anterior and posterior white matter, splenium of the corpus callosum, lentiform nucleus, pulvinar nucleus of the thalamus, posterior limb of the internal capsule, and optic radiations, thus including regions traditionally associated with hypoxia–ischemia or hypoglycemia. No associations were found between lower minimum glucose levels and DTI changes in any regions tested, or between glucose levels and MR spectroscopy.

Conclusions

In this cohort of neonatal encephalopathy with therapeutic hypothermia, higher maximal glucose on the first day of life was associated with widespread microstructural changes, but lower minimum glucose levels were not associated with changes in any of the regions tested. Long-term follow-up will determine if imaging findings translate to long-term outcomes.

Association of Type 1 Diabetes and Hypoglycemic and Hyperglycemic Events and Risk of Dementia

OBJECTIVE

To determine whether severe hypoglycemic and hyperglycemic events are associated with longitudinal dementia risk in older adults with type 1 diabetes.

METHODS

A longitudinal cohort study followed up 2,821 members of an integrated health care delivery system with type 1 diabetes from 1997 to 2015. Hypoglycemic and hyperglycemic events requiring emergency room or hospitalization were abstracted from medical records beginning January 1, 1996, through cohort entry. Participants were followed up for dementia diagnosis through September 30, 2015. Dementia risk was examined with Cox proportional hazard models adjusted for age (as time scale), sex, race/ethnicity, hemoglobin A1c, depression, stroke, and nephropathy.

RESULTS

Among 2,821 older adults (mean age 56 years) with type 1 diabetes, 398 (14%) had a history of severe hypoglycemia, 335 (12%) had severe hyperglycemia, and 87 (3%) had both. Over a mean 6.9 years of follow-up, 153 individuals (5.4%) developed dementia. In fully adjusted models, individuals with hypoglycemic events had 66% greater risk of dementia than those without a hypoglycemic event (hazard ratio [HR] 1.66, 95% confidence interval [CI] 1.09, 2.53), while those with hyperglycemic events had >2 times the risk (HR 2.11, 95% CI 1.24, 3.59) than those without a hyperglycemic event. There was a 6-fold greater risk of dementia in individuals with both severe hypoglycemia and hyperglycemia vs those with neither (HR 6.20, 95% CI 3.02, 12.70).

CONCLUSIONS

For older individuals with type 1 diabetes, severe hypoglycemic and hyperglycemic events are associated with increased future risk of dementia.

The association between systemic autoimmune disorders and epilepsy and its clinical implications

Systemic autoimmune disorders occur more frequently in patients with epilepsy than in the general population, suggesting shared disease mechanisms. The risk of epilepsy is elevated across the spectrum of systemic autoimmune disorders but is highest in systemic lupus erythematosus and type 1 diabetes mellitus. Vascular and metabolic factors are the most important mediators between systemic autoimmune disorders and epilepsy. Systemic immune dysfunction can also affect neuronal excitability, not only through innate immune activation and blood-brain barrier dysfunction in most epilepsies but also adaptive immunity in autoimmune encephalitis. The presence of systemic autoimmune disorders in subjects with acute seizures warrants evaluation for infectious, vascular, toxic and metabolic causes of acute symptomatic seizures, but clinical signs of autoimmune encephalitis should not be missed. Immunosuppressive medications may have antiseizure properties and trigger certain drug interactions with antiseizure treatments. A better understanding of mechanisms underlying the co-existence of epilepsy and systemic autoimmune disorders is needed to guide new antiseizure and anti-epileptogenic treatments. This review aims to summarize the epidemiological evidence for systemic autoimmune disorders as comorbidities of epilepsy, explore potential immune and non-immune mechanisms, and provide practical implications on diagnostic and therapeutic approach to epilepsy in those with comorbid systemic autoimmune disorders.

Brain injury in children with diabetic ketoacidosis: Review of the literature and a proposed pathophysiologic pathway for the development of cerebral edema

Cerebral edema (CE) is a potentially devastating complication of diabetic ketoacidosis (DKA) that almost exclusively occurs in children. Since its first description in 1936, numerous risk factors have been identified; however, there continues to be uncertainty concerning the mechanisms that lead to its development. Currently, the most widely accepted hypothesis posits that CE occurs as a result of ischemia-reperfusion injury, with inflammation and impaired cerebrovascular autoregulation contributing to its pathogenesis. The role of specific aspects of DKA treatment in the development of CE continues to be controversial. This review critically examines the literature on the pathophysiology of CE and attempts to categorize the findings by types of brain injury that contribute to its development: cytotoxic, vasogenic, and osmotic. Utilizing this scheme, we propose a multifactorial pathway for the development of CE in patients with DKA.

Disrupted Regional Cerebral Blood Flow in Children With Newly-Diagnosed Type 1 Diabetes Mellitus: An Arterial Spin Labeling Perfusion Magnetic Resonance Imaging Study

Object: Diabetes is associated with cerebral vascular dysfunction and increased vascular cognitive impairment. The objective of this study was to use arterial spin labeling (ASL) perfusion-weighted magnetic resonance imaging to investigate whether cerebral perfusion was changed in newly-diagnosed children with type 1 diabetes mellitus (T1DM) and the possible relationship between aberrant cerebral blood flow (CBF) with cognitive as well as clinical variables.

Methods: Between January 2017 and February 2018, 34 children with newly-diagnosed T1DM and 34 age, gender, and education-matched healthy controls were included. Three dimensional pseudo-continuous ASL perfusion MRI was used to evaluate CBF. A conventional T2WI sequence was added to exclude intracranial disease. Regions with CBF differences between T1DM children and the controls were detected via voxel-wise comparisons in REST software. Associations among the result of neuropsychological test, clinical variables, and CBF values of different brains were investigated by using partial correlation analysis.

Results: Compared with the controls, T1DM children show decreased CBF in the left calcarine and postcentral gyrus, and right precentral gyrus. The perfusion in the postcentral gyrus was positively correlated with IQ performance. No significant correlations were found between CBF and HbA1c, blood glucose level before imaging and IQ in other brain regions in T1DM children.

Conclusion: There is an abnormal cerebral perfusion in children with newly diagnosed T1DM. The visual and sensorimotor areas are brain areas where perfusion is prone to change at the beginning of T1DM. Our study provided clues for cerebral pathophysiological changes in the initial stage of T1DM.

n-3 Fatty Acid and Its Metabolite 18-HEPE Ameliorate Retinal Neuronal Cell Dysfunction by Enhancing Müller BDNF in Diabetic Retinopathy

Diabetic retinopathy (DR) is a widespread vision-threatening disease, and neuroretinal abnormality should be considered as an important problem. Brain-derived neurotrophic factor (BDNF) has recently been considered as a possible treatment to prevent DR-induced neuroretinal damage, but how BDNF is upregulated in DR remains unclear. We found an increase in hydrogen peroxide (H₂O₂) in the vitreous of patients with DR. We confirmed that human retinal endothelial cells secreted H₂O₂ by high glucose, and H₂O₂ reduced cell viability of MIO-M1, Müller glia cell line, PC12D, and the neuronal cell line and lowered BDNF expression in MIO-M1, whereas BDNF administration recovered PC12D cell viability. Streptozocin-induced diabetic rats showed reduced BDNF, which is mainly expressed in the Müller glia cell. Oral intake of eicosapentaenoic acid ethyl ester (EPA-E) ameliorated BDNF reduction and oscillatory potentials (OPs) in electroretinography (ERG) in DR. Mass spectrometry revealed an increase in several EPA metabolites in the eyes of EPA-E-fed rats. In particular, an EPA metabolite, 18-hydroxyeicosapentaenoic acid (18-HEPE), induced BDNF upregulation in Müller glia cells and recovery of OPs in ERG. Our results indicated diabetes-induced oxidative stress attenuates neuroretinal function, but oral EPA-E intake prevents retinal neurodegeneration via BDNF in Müller glia cells by increasing 18-HEPE in the early stages of DR.

Brain Metabolism Alterations in Type 2 Diabetes: What Did We Learn From Diet-Induced Diabetes Models?

Type 2 diabetes (T2D) is a metabolic disease with impact on brain function through mechanisms that include glucose toxicity, vascular damage and blood–brain barrier (BBB) impairments, mitochondrial dysfunction, oxidative stress, brain insulin resistance, synaptic failure, neuroinflammation, and gliosis. Rodent models have been developed for investigating T2D, and have contributed to our understanding of mechanisms involved in T2D-induced brain dysfunction. Namely, mice or rats exposed to diabetogenic diets that are rich in fat and/or sugar have been widely used since they develop memory impairment, especially in tasks that depend on hippocampal processing. Here we summarize main findings on brain energy metabolism alterations underlying dysfunction of neuronal and glial cells promoted by diet-induced metabolic syndrome that progresses to a T2D phenotype.

Startling hyperglycaemia with transient beta cell stunning in a patient with type 2 diabetes

A 59-year-old woman unaware of having diabetes was transferred due to coma. Upon discovery at home, her consciousness on the Glasgow Coma Scale was E1V2M4, BP 95/84 mmHg, body temperature 34.7°C. On arrival at ER, height was 1.63 m, weight 97 kg, plasma glucose (PG) 1,897 mg/dL, HbA_1c 13.6%, osmolality 421 mosm/kg, arterial pH 7.185, lactate 6.34 mmol/L, β-hydroxybutyrate 7.93 mmol/L. With saline and regular insulin infusion, PG was lowered to 1,440 mg/dL at 2 hours and then to 250 mg/dL by Day 3, and consciousness normalized by Day 5. On admission, serum immunoreactive insulin (IRI) was undetectable (<0.03 U/mL), C-peptide immunoreactivity (CPR) undetectable (<0.003 ng/mL), and anti-glutamic acid decarboxylase antibody negative. Following the above-described treatment, fasting PG was 186 mg/dL and CPR 1.94 ng/mL, respectively, on Day 14; 2-h post-breakfast PG 239 mg/dL and CPR 6.28 ng/mL, respectively, on Day 18. The patient discharged on Day 18 with 1,800 kcal diet, 32 U insulin glargine and 40 mg gliclazide. Fifteen months later at outpatient clinic, her HbA_1c was 6.9% and 2-h post-breakfast PG 123 mg/dL and CPR 5.30 ng/dL with 750 mg metformin, 10 mg gliclazide and 18 U insulin glargine. Transient, but total cessation of insulin secretion was documented in a patient with type 2 diabetes under severe metabolic decompensation. Swift, sustained recovery of insulin release indicated that lack of insulin at the time of emergency was due to secretory failure, i.e., unresponsive exocytotic machinery or depletion of releasable insulin, rather than loss of beta cells.

Lactate infusion increases brain energy content during euglycemia but not hypoglycemia in healthy men

A special characteristic of the brain is the usage of lactate as alternative fuel instead of glucose to preserve its energy homeostasis. This physiological function is valid for sufficient cerebral glucose supply, as well as presumably during hypoglycemia, given that exogenous lactate infusion suppresses hormonal counterregulation. However, it is not yet clarified whether this effect is mediated by the use of lactate as an alternative cerebral energy substrate or any other mechanism. We hypothesized that under conditions of limited access to glucose (ie, during experimental hypoglycemia) lactate infusion would prevent hypoglycemia-induced neuroenergetic deficits in a neuroprotective way. In a randomized, double-blind, crossover study, lactate vs placebo infusion was compared during hyperinsulinemic-hypoglycemic clamps in 16 healthy young men. We measured the cerebral high-energy phosphate content - ie, adenosine triphosphate (ATP), phosphocreatine (PCr) and inorganic phosphate (Pi) levels - by ³¹ P-magnetic resonance spectroscopy as well as the neuroendocrine stress response. During euglycemia, lactate infusion increased ATP/Pi as well as PCr/Pi ratios compared with baseline values and placebo infusion. During hypoglycemia, there were no differences between the lactate and the placebo condition in both ratios. Hormonal counterregulation was significantly diminished upon lactate infusion. Our data demonstrate an elevated cerebral high-energy phosphate content upon lactate infusion during euglycemia, whereas there was no such effect during experimental hypoglycemia. Nevertheless, lactate infusion suppressed hypoglycemic hormonal counterregulation. Lactate thus adds to cerebral energy provision during euglycemia and may contribute to an increase in ATP reserves, which in turn protects the brain against neuroglucopenia under recurrent hypopglycemic conditions, eg, in diabetic patients.

Evidenced-Based Nutrition for Gestational Diabetes Mellitus

PURPOSE OF REVIEW

To review the latest evidence for dietary interventions for treatment of gestational diabetes (GDM).

RECENT FINDINGS

High-quality systematic reviews demonstrate no major advantages between the low-carbohydrate or calorie-restricted diets. However, the low glycemic index (GI) diet, characterized by intake of high-quality, complex carbohydrates, demonstrated lower insulin use and reduced risk of macrosomia in multiple reviews. Recent evidence suggests the Mediterranean diet is safe in pregnancy, though trials are needed to determine its efficacy over conventional dietary advice. Currently, there are insufficient data to support the safety of the ketogenic diet for the treatment of GDM. The low GI diet may improve maternal and neonatal outcomes in GDM. The liberalized carbohydrate intake is less restrictive, culturally adaptable, and may improve long-term maternal adherence. Further research is needed to establish the optimal, most sustainable, and most acceptable medical nutrition therapy for management of women with GDM.

Metabolic encephalopathy secondary to diabetic ketoacidosis: a case report

INTRODUCTION

Metabolic encephalopathy is a rare but potentially devastating complication of diabetic ketoacidosis (DKA). This case highlights the dramatic cognitive decline of a young man due to metabolic encephalopathy complicating DKA. The aims of this case report are to highlight metabolic encephalopathy as a complication of DKA and to explore the current research in diabetic related brain injury. The importance of investigation and treatment of reversible causes of encephalopathy is also demonstrated.

CASE PRESENTATION

A 35-year-old man with a background of type 1 diabetes mellitus (T1DM) and relapsing remitting multiple sclerosis (RRMS) presented to the emergency department (ED) in a confused and agitated state. Prior to admission he worked as a caretaker in a school, smoked ten cigarettes per day, took excess alcohol and smoked cannabis twice per week. Following initial investigations, he was found to be in DKA. Despite timely and appropriate management his neurological symptoms and behavioural disturbance persisted. Neuroimaging revealed temporal lobe abnormalities consistent with an encephalopathic process. The patient underwent extensive investigation looking for evidence of autoimmune, infective, metabolic, toxic and paraneoplastic encephalopathy, with no obvious cause demonstrated. Due to persistent radiological abnormalities a temporal lobe biopsy was performed which showed marked astrocytic gliosis without evidence of vasculitis, inflammation, infarction or neoplasia. A diagnosis of metabolic encephalopathy secondary to DKA was reached. The patient's cognitive function remained impaired up to 18 months post presentation and he ultimately required residential care.

CONCLUSIONS

Metabolic encephalopathy has been associated with acute insults such as DKA, but importantly, the risk of cerebral injury is also related to chronic hyperglycaemia. Mechanisms of cerebral injury in diabetes mellitus continue to be investigated. DKA poses a serious and significant neurological risk to patients with diabetes mellitus. To our knowledge this is the second case report describing this acute complication.

Elevated brain glutamate levels in type 1 diabetes: correlations with glycaemic control and age of disease onset but not with hypoglycaemia awareness status

AIMS/HYPOTHESIS

Chronic hyperglycaemia in type 1 diabetes affects the structure and functioning of the brain, but the impact of recurrent hypoglycaemia is unclear. Changes in the neurochemical profile have been linked to loss of neuronal function. We therefore aimed to investigate the impact of type 1 diabetes and burden of hypoglycaemia on brain metabolite levels, in which we assumed the burden to be high in individuals with impaired awareness of hypoglycaemia (IAH) and low in those with normal awareness of hypoglycaemia (NAH).

METHODS

We investigated 13 non-diabetic control participants, 18 individuals with type 1 diabetes and NAH and 13 individuals with type 1 diabetes and IAH. Brain metabolite levels were determined by analysing previously obtained ¹H magnetic resonance spectroscopy data, measured under hyperinsulinaemic-euglycaemic conditions.

RESULTS

Brain glutamate levels were higher in participants with diabetes, both with NAH (+15%, p = 0.013) and with IAH (+19%, p = 0.003), compared with control participants. Cerebral glutamate levels correlated with HbA_1c levels (r = 0.40; p = 0.03) and correlated inversely (r = -0.36; p = 0.04) with the age at diagnosis of diabetes. Other metabolite levels did not differ between groups, apart from an increase in aspartate in IAH.

CONCLUSIONS/INTERPRETATION

In conclusion, brain glutamate levels are elevated in people with type 1 diabetes and correlate with glycaemic control and age of disease diagnosis, but not with burden of hypoglycaemia as reflected by IAH. This suggests a potential role for glutamate as an early marker of hyperglycaemia-induced cerebral complications of type 1 diabetes. ClinicalTrials.gov NCT03286816; NCT02146404; NCT02308293.

The effect of type 1 diabetes on the developing brain

The effect of type 1 diabetes on the developing brain is a topic of primary research interest. A variety of potential dysglycaemic insults to the brain can cause cellular and structural injury and lead to altered neuropsychological outcomes. These outcomes might be subtle in terms of cognition but appear to persist into adult life. Age and circumstance at diagnosis appear to play a substantial role in potential CNS injury. A history of diabetic ketoacidosis and chronic hyperglycaemia appear to be more injurious than previously suspected, whereas a history of severe hypoglycaemia is perhaps less injurious. Neurocognitive deficits manifest across multiple cognitive domains, including executive function and speed of information processing. Some evidence suggests that subtle brain injury might directly contribute to psychological and mental health outcomes. Impaired executive function and mental health, in turn, could affect patients' adherence and the ability to make adaptive lifestyle choices. Impaired executive functioning creates a potential feedback loop of diabetic dysglycaemia leading to brain injury, further impaired executive function and mental health, which results in suboptimal adherence, and further dysglycaemia. Clinicians dealing with patients with suboptimal glycaemic outcomes should be aware of these potential issues.

Intralipid/Heparin Infusion Alters Brain Metabolites Assessed With 1H-MRS Spectroscopy in Young Healthy Men

CONTEXT

We previously demonstrated that insulin infusion altered metabolite concentrations in cerebral tissues assessed with proton magnetic resonance spectroscopy (1H-MRS) in young subjects with high insulin sensitivity, but not in those with low insulin sensitivity. Fat overload is an important factor leading to insulin resistance.

OBJECTIVE

The purpose of the current study was to examine the effect of elevated circulating free fatty acid (FFA) levels on metabolites in cerebral tissues assessed with 1H-MRS.

DESIGN

The study group comprised 10 young, healthy male subjects. 1H-MRS was performed at baseline and after 4-hour Intralipid (Fresenius Kabi)/heparin or saline infusions administered in random order. Voxels were positioned in the left frontal lobe, left temporal lobe, and hippocampus. The ratios of N-acetylaspartate (NAA), choline (Cho)-containing compounds, myo-inositol (mI), and glutamate/glutamine/γ-aminobutyric acid complex (Glx) to creatine (Cr) and nonsuppressed water signal were determined.

RESULTS

Intralipid/heparin infusion resulted in a significant increase in circulating FFAs (P < 0.0001). Significant changes in brain neurometabolite concentrations in response to Intralipid/heparin infusion were increases in frontal mI/Cr (P = 0.041) and mI/H2O (P = 0.037), decreases in frontal and hippocampal Glx/Cr (P = 0.018 and P = 0.015, respectively) and Glx/H2O (P = 0.03 and P = 0.067, respectively), and a decrease in hippocampal NAA/Cr (P = 0.007) and NAA/H2O (P = 0.019). No changes in neurometabolites were observed during the saline infusion.

CONCLUSIONS

Acute circulating FFA elevation influenced cerebral metabolites in healthy humans and lipid-induced insulin resistance could be partly responsible for these effects.

Persistence of abnormalities in white matter in children with type 1 diabetes

AIMS/HYPOTHESIS

Prior studies suggest white matter growth is reduced and white matter microstructure is altered in the brains of young children with type 1 diabetes when compared with brains of non-diabetic children, due in part to adverse effects of hyperglycaemia. This longitudinal observational study examines whether dysglycaemia alters the developmental trajectory of white matter microstructure over time in young children with type 1 diabetes.

METHODS

One hundred and eighteen children, aged 4 to <10 years old with type 1 diabetes and 58 age-matched, non-diabetic children were studied at baseline and 18 months, at five Diabetes Research in Children Network clinical centres. We analysed longitudinal trajectories of white matter using diffusion tensor imaging. Continuous glucose monitoring profiles and HbA_1c levels were obtained every 3 months.

RESULTS

Axial diffusivity was lower in children with diabetes at baseline (p = 0.022) and at 18 months (p = 0.015), indicating that differences in white matter microstructure persist over time in children with diabetes. Within the diabetes group, lower exposure to hyperglycaemia, averaged over the time since diagnosis, was associated with higher fractional anisotropy (p = 0.037). Fractional anisotropy was positively correlated with performance (p < 0.002) and full-scale IQ (p < 0.02).

CONCLUSIONS/INTERPRETATION

These results suggest that hyperglycaemia is associated with altered white matter development, which may contribute to the mild cognitive deficits in this population.

β-Hydroxybutyrate Detection with Proton MR Spectroscopy in Children with Drug-Resistant Epilepsy on the Ketogenic Diet

BACKGROUND AND PURPOSE

The ketogenic diet, including both classic and modified forms, is an alternative to antiepileptic medications used in the treatment of drug-resistant epilepsy. We sought to evaluate the utility of proton MR spectroscopy for the detection of β-hydroxybutyrate in a cohort of children with epilepsy treated with the ketogenic diet and to correlate brain parenchymal metabolite ratios obtained from spectroscopy with β-hydroxybutyrate serum concentrations.

MATERIALS AND METHODS

Twenty-three spectroscopic datasets acquired at a TE of 288 ms in children on the ketogenic diet were analyzed with LCModel using a modified basis set that included a simulated β-hydroxybutyrate resonance. Brain parenchymal metabolite ratios were calculated. Metabolite ratios were compared with serum β-hydroxybutyrate concentrations, and partial correlation coefficients were calculated using patient age as a covariate.

RESULTS

β-hydroxybutyrate blood levels were highly correlated to brain β-hydroxybutyrate levels, referenced as either choline, creatine, or N-acetylaspartate. They were inversely but more weakly associated with N-acetylaspartate, regardless of the ratio denominator. No strong concordance with lactate was demonstrated.

CONCLUSIONS

Clinical MR spectroscopy in pediatric patients on the ketogenic diet demonstrated measurable β-hydroxybutyrate, with a strong correlation to β-hydroxybutyrate blood levels. These findings may serve as an effective tool for noninvasive monitoring of ketosis in this population. An inverse correlation between serum β-hydroxybutyrate levels and brain tissue N-acetylaspartate suggests that altered amino acid handling contributes to the antiepileptogenic effect of the ketogenic diet.

Pregnancy Ketonemia and Development of the Fetal Central Nervous System

Glucose is the major source of energy for the human brain which in turn uses ketone bodies as a supplement for energy deficit in glucose cell deficiency conditions. Pregnancy complicated by gestational diabetes is a condition associated with significantly increased risk of ketonemia development. The data available proves a changing influence of ketones on the central nervous system during fetal life and in adults as well. Ketone bodies freely pass through the placenta. They can affect fetal growth and organ damage development, especially the central nervous system. As agreed in the current recommendation of the diabetes associations, it is not obligatory for the attending doctor to conduct a routine inspection of ketone bodies during diabetes treatment in pregnancy. This article is a literature review of ketones' effect on the central nervous system and an attempt to initiate discussion whether we should consider including ketonemia assessment into the standard care package for pregnant women with diabetes and begin some research on the explanation of its influence on fetal development.

Treatment with the KCa3.1 inhibitor TRAM-34 during diabetic ketoacidosis reduces inflammatory changes in the brain

BACKGROUND

Diabetic ketoacidosis (DKA) causes brain injuries in children ranging from subtle to life-threatening. Previous studies suggest that DKA-related brain injury may involve both stimulation of Na-K-Cl cotransport and microglial activation. Other studies implicate the Na-K-Cl cotransporter and the Ca-activated K channel KCa3.1 in activation of microglia and ischemia-induced brain edema. In this study, we determined whether inhibiting cerebral Na-K-Cl cotransport or KCa3.1 could reduce microglial activation and decrease DKA-related inflammatory changes in the brain.

METHODS

Using immunohistochemistry, we investigated cellular alterations in brain specimens from juvenile rats with DKA before, during and after insulin and saline treatment. We compared findings in rats treated with and without bumetanide (an inhibitor of Na-K-Cl cotransport) or the KCa3.1 inhibitor TRAM-34.

RESULTS

Glial fibrillary acidic protein (GFAP) staining intensity was increased in the hippocampus during DKA, suggesting reactive astrogliosis. OX42 staining intensity was increased during DKA in the hippocampus, cortex and striatum, indicating microglial activation. Treatment with TRAM-34 decreased both OX42 and GFAP intensity suggesting a decreased inflammatory response to DKA. Treatment with bumetanide did not significantly alter OX42 or GFAP intensity.

CONCLUSIONS

Inhibiting KCa3.1 activity with TRAM-34 during DKA treatment decreases microglial activation and reduces reactive astrogliosis, suggesting a decreased inflammatory response.

Serum Levels of Neuron-Specific Enolase in Children With Diabetic Ketoacidosis

Neuron-specific enolase is a sensitive marker of neuronal damage in various neurologic disorders. This study aimed to measure serum neuron-specific enolase levels at different time points and severities of diabetic ketoacidosis. This study included 90 children (age 9.2 ± 3.4 years) with diabetic ketoacidosis. Neuron-specific enolase was measured at 3 time points (baseline and after 12 and 24 hours of starting treatment). Among patients, 74.4% had diagnosis of new diabetes, 60% had Glasgow Coma Scale score <15, and 75.6% had moderate/severe diabetic ketoacidosis. Compared with controls (n = 30), children with diabetic ketoacidosis had higher neuron-specific enolase levels at the 3 time points ( P = .0001). In multiple regression analysis, the factors associated with higher neuron-specific enolase levels were younger age, higher glucose, lower pH, and bicarbonate values. This study indicates that serum neuron-specific enolase is elevated in diabetic ketoacidosis and correlated with the severity of hyperglycemia, ketosis, and acidosis. This study indicates that diabetic ketoacidosis may cause neuronal injury from which the patients recovered partially but not completely.

Cognition and Type 1 Diabetes in Children and Adolescents

IN BRIEF In children and adolescents with type 1 diabetes, exposure to glycemic extremes (severe hypoglycemia, chronic hyperglycemia, and diabetic ketoacidosis) overlaps with the time period of most active brain and cognitive development, leading to concerns that these children are at risk for cognitive side effects. This article summarizes the existing literature examining the impact of glycemic extremes on cognitive function and brain structure in youth with type 1 diabetes and points out areas for future research.

Neuroimaging findings in acute pediatric diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a state of severe insulin deficiency and a serious complication in children with diabetes mellitus type 1. In a small number of children, DKA is complicated by injury of the central nervous system. These children have a significant mortality and high long-term neurological morbidity. Cerebral edema is the most common neuroimaging finding in children with DKA and may cause brain herniation. Ischemic or hemorrhagic stroke during the acute DKA episode is less common and accounts for approximately 10% of intracerebral complications of DKA. Here we present the neuroimaging findings of two children with DKA and brain injury. Familiarity with the spectrum of neuroimaging findings seen in pediatric DKA is important to allow early detection as well as initiation of therapy and, hence, prevent complications of the central nervous system.

Cerebral Accidents in Pediatric Diabetic Ketoacidosis: Different Complications and Different Evolutions

Diabetic ketoacidosis (DKA) may be associated with neurologic complications: the most common is cerebral edema while the risk of venous and arterial stroke is rare. There is a pathogenetic link between DKA, hypercoagulability and stroke, whose risk is underestimated by clinicians. Our cases present a wide spectrum of cerebral accidents during DKA, the first one being diffuse cerebral edema, the second one venous stroke after 5 days of DKA resolution, while the third one multifocal edema suspected to be extrapontine myelinolysis although without electrolyte imbalance. Our cases suggest that DKA requires very accurate treatment, particularly at an early age, and it can be complicated by cerebral accidents even with appropriate medical care.

Ketoacidosis in diabetic pregnancy

Diabetic ketoacidosis (DKA) is a serious medical and obstetrical emergency previously considered typical of type 1 diabetes but now reported also in type 2 and GDM patients. Although it is a fairly rare condition, DKA in pregnancy can compromise both fetus and mother. Metabolic changes occurring during pregnancy predispose to DKA in fact it can develop even in setting of normoglycemia. This article will provide the reader with information regarding the pathophysiology underlying DKA, in particular euglycemic DKA, and will provide information regarding all possible effects of ketones on the fetus.

The Impact of Diabetes on Brain Function in Childhood and Adolescence

A constant supply of glucose to the brain is critical for normal cerebral metabolism. The dysglycemia of type 1 diabetes (T1D) can affect activity, survival, and function of neural cells. Clinical studies in T1D have shown impairments in brain morphology and function. The most neurotoxic milieu seems to be young age and/or diabetic ketoacidosis at onset, severe hypoglycemia under the age of 6 years followed by chronic hyperglycemia. Adverse cognitive outcomes seem to be associated with poorer mental health outcomes. It is imperative to improve outcomes by investigating the mechanisms of injury so that neuroprotective strategies independent of glycemia can be identified.

Hyperglycemia is associated with simultaneous alterations in electrical brain activity in youths with type 1 diabetes mellitus

OBJECTIVE

To assess the association between hyperglycemia and electrical brain activity in type 1 diabetes mellitus (T1DM).

METHODS

Nine youths with T1DM were monitored simultaneously and continuously by EEG and continuous glucose monitor system, for 40 h. EEG powers of 0.5-80 Hz frequency bands in all the different brain regions were analyzed according to interstitial glucose concentration (IGC) ranges of 4-11 mmol/l, 11-15.5 mmol/l and >15.5 mmol/l. Analysis of variance was used to examine the differences in EEG power of each frequency band between the subgroups of IGC. Analysis was performed separately during wakefulness and sleep, controlling for age, gender and HbA1c.

RESULTS

Mean IGC was 11.49 ± 5.26 mmol/l in 1253 combined measurements. IGC>15.5 mmol/l compared to 4-11 mmol/l was associated during wakefulness with increased EEG power of low frequencies and with decreased EEG power of high frequencies. During sleep, it was associated with increased EEG power of low frequencies in all brain areas and of high frequencies in frontal and central areas.

CONCLUSIONS

Asymptomatic transient hyperglycemia in youth with T1DM is associated with simultaneous alterations in electrical brain activity during wakefulness and sleep.

SIGNIFICANCE

The clinical implications of immediate electrical brain alterations under hyperglycemia need to be studied and may lead to adaptations of management.

Brain cell swelling during hypocapnia increases with hyperglycemia or ketosis

BACKGROUND

Severe hypocapnia reduces cerebral blood flow (CBF) and is known to be a risk factor for diabetic ketoacidosis (DKA)-related cerebral edema and cerebral injury in children. Reductions in CBF resulting from hypocapnia alone, however, would not be expected to cause substantial cerebral injury. We hypothesized that either hyperglycemia or ketosis might alter the effects of hypocapnia on CBF and/or cerebral edema associated with CBF reduction.

METHODS

We induced hypocapnia (pCO₂ 20 ± 3 mmHg) via mechanical ventilation in three groups of juvenile rats: 25 controls, 22 hyperglycemic rats (serum glucose 451 ± 78 mg/dL), and 15 ketotic rats (β-hydroxy butyrate 3.0 ± 1.0 mmol/L). We used magnetic resonance imaging to measure CBF and apparent diffusion coefficient (ADC) values in these groups and in 17 ventilated rats with normal pCO₂ (40 ± 3 mmHg). In a subset (n = 35), after 2 h of hypocapnia, pCO₂ levels were normalized (40 ± 3 mmHg) and ADC and CBF measurements were repeated.

RESULTS

Declines in CBF with hypocapnia occurred in all groups. Normalization of pCO₂ after hypocapnia resulted in hyperemia in the striatum. These effects were not substantially altered by hyperglycemia or ketosis. Declines in ADC (suggesting brain cell swelling) during hypocapnia, however, were greater during both hyperglycemia and ketosis.

CONCLUSIONS

We conclude that brain cell swelling associated with hypocapnia is increased by both hyperglycemia and ketosis, suggesting that these metabolic conditions may make the brain more vulnerable to injury during hypocapnia.

Blood-brain barrier Na transporters in ischemic stroke

Blood-brain barrier (BBB) endothelial cells form a barrier that is highly restrictive to passage of solutes between blood and brain. Many BBB transport mechanisms have been described that mediate transcellular movement of solutes across the barrier either into or out of the brain. One class of BBB transporters that is all too often overlooked is that of the ion transporters. The BBB has a rich array of ion transporters and channels that carry Na, K, Cl, HCO3, Ca, and other ions. Many of these are asymmetrically distributed between the luminal and abluminal membranes, giving BBB endothelial cells the ability to perform vectorial transport of ions across the barrier between blood and brain. In this manner, the BBB performs the important function of regulating the volume and composition of brain interstitial fluid. Through functional coupling of luminal and abluminal transporters and channels, the BBB carries Na, Cl, and other ions from blood into brain, producing up to 30% of brain interstitial fluid in healthy brain. During ischemic stroke cerebral edema forms by processes involving increased activity of BBB luminal Na transporters, resulting in "hypersecretion" of Na, Cl, and water into the brain interstitium. This review discusses the roles of luminal BBB Na transporters in edema formation in stroke, with an emphasis on Na-K-Cl cotransport and Na/H exchange. Evidence that these transporters provide effective therapeutic targets for reduction of edema in stroke is also discussed, as are recent findings regarding signaling pathways responsible for ischemia stimulation of the BBB Na transporters.

Factors associated with cognitive decline in older adults with type 2 diabetes mellitus during a 6-year observation

AIMS

Type 2 diabetes mellitus (T2DM) is a risk for cognitive decline in older adults. The current study was carried out to determine the factors associated with cognitive decline.

METHODS

The older T2DM patients (aged ≥65 years, mean age 79.2 ± 5.1 years) were observed for 6 years, and the mean values in clinical indicators of participants with and without cognitive decline over a 6-year period were compared. Then, multiple logistic analysis was carried out to determine the factors associated with cognitive decline. Separate analyses were also carried out for each of five cognitive assessments (Mini-Mental State Examination, word immediate and delayed recall, Stroop test, digit symbol substitution).

RESULTS

In the composite of several cognitive assessments, higher age and a lower level of high-density lipoprotein cholesterol were associated with cognitive decline in older T2DM patients. Lower systolic blood pressure was associated with a decline in delayed word list recall. Higher plasma insulin level was associated with a decline in the Stroop test performance.

CONCLUSION

Lower high-density lipoprotein cholesterol was significantly associated with general cognitive decline in older T2DM patients during our 6-year observation. Several other factors were also associated with cognitive assessments of various cognitive domains.

Quantitative imaging biomarkers for the evaluation of cardiovascular complications in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a prevalent condition in aged populations. Cardiovascular diseases are leading causes of death and disability in patients with T2DM. Traditional strategies for controlling the cardiovascular complications of diabetes primarily target a cluster of well-defined risk factors, such as hyperglycemia, lipid disorders and hypertension. However, there is controversy over some recent clinical trials aimed at evaluating efficacy of intensive treatments for T2DM. As a powerful tool for quantitative cardiovascular risk estimation, multi-disciplinary cardiovascular imaging have been applied to detect and quantify morphological and functional abnormalities in the cardiovascular system. Quantitative imaging biomarkers acquired with advanced imaging procedures are expected to provide new insights to stratify absolute cardiovascular risks and reduce the overall costs of health care for people with T2DM by facilitating the selection of optimal therapies. This review discusses principles of state-of-the-art cardiovascular imaging techniques and compares applications of those techniques in various clinical circumstances. Individuals measurements of cardiovascular disease burdens from multiple aspects, which are closely related to existing biomarkers and clinical outcomes, are recommended as promising candidates for quantitative imaging biomarkers to assess the responses of the cardiovascular system during diabetic regimens.

General aspects of diabetes mellitus

Diabetes mellitus is a heterogeneous group of disorders characterized by hyperglycemia due to an absolute or relative deficit in insulin production or action. The chronic hyperglycemia of diabetes mellitus is associated with end organ damage, dysfunction, and failure, including the retina, kidney, nervous system, heart, and blood vessels. The International Diabetes Federation (IDF) estimated an overall prevalence of diabetes mellitus to be 366 million in 2011, and predicted a rise to 552 million by 2030. The treatment of diabetes mellitus is determined by the etiopathology and is most commonly subdivided in type 1 and type 2 diabetes mellitus. There is a greater propensity towards hyperglycemia in individuals with coexisting genetic predisposition or concomitant drug therapy such as corticosteroids. The screening for diabetes mellitus may either be in the form of a 2hour oral glucose tolerance test, or via HbA1c testing, as recently recommended by the American Diabetes Association (ADA). Strong associations have been shown in observational studies suggesting poor clinical outcomes both with chronic hyperglycemia and acutely in intensive care settings. However, tight glycemic control in this setting is a contentious issue with an increased incidence of hypoglycemia and possible increase in morbidity and mortality. In a critically ill patient a glucose range of 140-180mg/dL (7.8-10.0mmol/L) should be maintained via continuous intravenous insulin infusion.

Coronary artery bypass grafting: a precipitating factor for perioperative diabetic ketoacidosis

Non-Insulin Dependent Diabetes Mellitus (NIDDM) is a common disease entity in patients with Coronary Artery Disease (CAD). Diabetic Ketoacidosis (DKA) is not only one of the major complications of Diabetes Mellitus but also a significant challenging clinical entity for the patients undergoing any elective or emergency surgery. Coronary Artery Bypass Grafting (CABG) being done in a patient with DKA has not been reported. We are presenting a rare case with DKA in whom CABG was carried out in a hospital devoted exclusively to cardiac cases. Insulin was given in very large doses as a part of therapeutic regimen and the outcome was favorable. This report concludes that if a patient undergoing urgent cardiac surgery incidentally develops DKA after induction of anesthesia, then the operation can be carried out provided DKA is managed aggressively. Also, major stress factors like cardio pulmonary bypass (CPB) and hypothermia should be avoided and care should be taken to avoid cerebral edema.