Receptor for advanced glycation end products and neuronal deficit in the fatal brain edema of diabetic ketoacidosis

Effects of Gestational and Lactational Lead Exposure and High Fat Diet Feeding on Cerebellar Development of Postnatal Rat Offspring

Obesity and heavy metals, such as lead (Pb), are detrimental to the adult brain because they impair cognitive function and structural plasticity. However, the effects of co-administration of Pb and a high-fat diet (HFD) on the developing cerebellum is not clearly elucidated. We investigated the effects of Pb exposure (0.3% lead acetate) on developing cerebellum in the pups of an HFD-fed obese rat model. One week before mating, we fed a chow diet (CD) or HFD to the rats for one week and additionally administered Pb to HFD-fed female SD rats. Thereafter, treatment with Pb and a HFD was continued during the gestational and lactational periods. On postnatal day 21, the pups were euthanized to sample the brain tissue and blood for further analysis. Blood Pb levels were significantly higher in HFD-fed rats than in CD-fed rats. Histologically, the prominent degeneration of Purkinje cells was induced by the co-administration of Pb and HFD. The calbindin-28Kd-, GAD67-, NMDAR1-, and PSD95-immunopositive Purkinje cells and inhibitory synapse-forming pinceau structures were significantly decreased following Pb and HFD co-administration. MBP-immunoreactive myelinated axonal fibers were also impaired by HFD but were significantly damaged by the co-administration of HFD and Pb. Oxidative stress-related Nrf2-HO1 signaling was activated by HFD feeding, and Pb exposure further aggravated oxidative stress, as demonstrated by the consumption of endogenous anti-oxidant in HFD-Pb rats. The pro-inflammatory response was also increased by the co-administration of HFD and Pb in the cerebellum of the rat offspring. The present results suggest that HFD and Pb treatment during the gestational and lactational periods are harmful to cerebellar development.

Function and therapeutic value of astrocytes in diabetic cognitive impairment

Diabetic cognitive impairment (DCI) is a complex complication of diabetes in the central nervous system, and its pathological mechanism is still being explored. Astrocytes are abundant glial cells in central nervous system that perform diverse functions in health and disease. Accumulating excellent research has identified astrocyte dysfunction in many neurodegenerative diseases (such as Alzheimer's disease, aging and Parkinson's disease), and summarized and discussed its pathological mechanisms and potential therapeutic value. However, the contribution of astrocytes to DCI has been largely overlooked. In this review, we first systematically summarized the effects and mechanisms of diabetes on brain astrocytes, and found that the diabetic environment (such as hyperglycemia, advanced glycation end products and cerebral insulin resistance) mediated brain reactive astrogliosis, which was specifically reflected in the changes of cell morphology and the remodeling of signature molecules. Secondly, we emphasized the contribution and potential targets of reactive astrogliosis to DCI, and found that reactive astrogliosis-induced increased blood-brain barrier permeability, glymphatic system dysfunction, neuroinflammation, abnormal cell communication and cholesterol metabolism dysregulation worsened cognitive function. In addition, we summarized effective strategies for treating DCI by targeting astrocytes. Finally, we discuss the application of new techniques in astrocytes, including single-cell transcriptome, in situ sequencing, and prospected new functions, new subsets and new targets of astrocytes in DCI.

Targeting choroid plexus epithelium as a novel therapeutic strategy for hydrocephalus

The choroid plexus is a tissue located in the lateral ventricles of the brain and is composed mainly of choroid plexus epithelium cells. The main function is currently thought to be the secretion of cerebrospinal fluid and the regulation of its pH, and more functions are gradually being demonstrated. Assistance in the removal of metabolic waste and participation in the apoptotic pathway are also the functions of choroid plexus. Besides, it helps to repair the brain by regulating the secretion of neuropeptides and the delivery of drugs. It is involved in the immune response to assist in the clearance of infections in the central nervous system. It is now believed that the choroid plexus is in an inflammatory state after damage to the brain. This state, along with changes in the cilia, is thought to be an abnormal physiological state of the choroid plexus, which in turn leads to abnormal conditions in cerebrospinal fluid and triggers hydrocephalus. This review describes the pathophysiological mechanism of hydrocephalus following choroid plexus epithelium cell abnormalities based on the normal physiological functions of choroid plexus epithelium cells, and analyzes the attempts and future developments of using choroid plexus epithelium cells as a therapeutic target for hydrocephalus.

Effects of TRAM-34 and minocycline on neuroinflammation caused by diabetic ketoacidosis in a rat model

INTRODUCTION

Diabetic ketoacidosis (DKA) causes acute and chronic neuroinflammation that may contribute to cognitive decline in patients with type 1 diabetes. We evaluated the effects of agents that reduce neuroinflammation (triarylmethane-34 (TRAM-34) and minocycline) during and after DKA in a rat model.

RESEARCH DESIGN AND METHODS

Juvenile rats with DKA were treated with insulin and saline, either alone or in combination with TRAM-34 (40 mg/kg intraperitoneally twice daily for 3 days, then daily for 4 days) or minocycline (45 mg/kg intraperitoneally daily for 7 days). We compared cytokine and chemokine concentrations in brain tissue lysates during DKA among the three treatment groups and in normal controls and diabetic controls (n=9-15/group). We also compared brain inflammatory mediator levels in these same groups in adult diabetic rats that were treated for DKA as juveniles.

RESULTS

Brain tissue concentrations of chemokine (C-C) motif ligand (CCL)3, CCL5 and interferon (IFNγ) were increased during acute DKA, as were brain cytokine composite scores. Both treatments reduced brain inflammatory mediator levels during acute DKA. TRAM-34 predominantly reduced chemokine concentrations (chemokine (C-X-C) motif ligand (CXCL-1), CCL5) whereas minocycline had broader effects, (reducing CXCL-1, tumor necrosis factor (TNFα), IFNγ, interleukin (IL) 2, IL-10 and IL-17A). Brain inflammatory mediator levels were elevated in adult rats that had DKA as juveniles, compared with adult diabetic rats without previous DKA, however, neither TRAM-34 nor minocycline treatment reduced these levels.

CONCLUSIONS

These data demonstrate that both TRAM-34 and minocycline reduce acute neuroinflammation during DKA, however, treatment with these agents for 1 week after DKA does not reduce long-term neuroinflammation.

Carnosine improves cognitive impairment through promoting SIRT6 expression and inhibiting ER stress in a diabetic encephalopathy model

Diabetic encephalopathy is one of complications of diabetes mellitus. Carnosine is a dipeptide composed of β-alanine and L-histidine. Study has shown that carnosine could ameliorate cognitive impairment in animal model with diabetes mellitus. However, the mechanism remains unclear. An animal model of type 2 diabetes (db/db mice) was used in this study. The animals were treated with 0.9 % saline or carnosine (100 mg/kg) for 8 weeks. Morris water maze was tested after drug administration. Oxidative stress-related factors malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), and pro-inflammatory factors inducible nitric oxide synthase (iNOS) were measured. Synapse-related protein postsynapticdensity 95 (PSD95) and brain-derived neurotrophic factor (BDNF) were detected by western blot. Besides, the expressions of sirtuin 6 (SIRT6), binding immunoglobulin protein (BIP), protein kinase R-like endoplasmic reticulum kinase (PERK), phospho-protein kinase R-like endoplasmic reticulum kinase (P-PERK), inositol-requiring enzyme-1α (IRE1α), phospho-inositol-requiring enzyme-1α (P-IRE1α), activating transcription factor 6 (ATF6), C/EBP-homologous protein (CHOP) in the hippocampus of the brain were detected. The results showed that treatment with carnosine ameliorated cognitive impairment in db/db mice. Carnosine reduced neuronal oxidative stress damage and iNOS expression in db/db mice. Meanwhile, carnosine relieved neurodegeneration in the hippocampus of db/db mice. Furthermore, carnosine promoted the expression of SIRT6 and reduced the expressions of endoplasmic reticulum (ER) related factors (BIP, P-PERK, P-IRE1α, ATF6, CHOP). In conclusion, these data suggested that the protective effect of carnosine against diabetic encephalopathy might be related to SIRT6/ER stress pathway.

Tryptophan, kynurenine pathway, and diabetic ketoacidosis in type 1 diabetes

Diabetic ketoacidosis (DKA) is a serious complication of complete insulin deficiency and insulin resistance in Type 1 diabetes (T1D). This results in the body producing high levels of serum ketones in an attempt to compensate for the insulin deficiency and decreased glucose utilization. DKA's metabolic and immunologic dysregulation results in gradual increase of systemic and cerebral oxidative stress, along with low grade systemic and cerebral inflammation and the development of pretreatment subclinical BE. During treatment the early progression of oxidative stress and inflammation is hypothesized to advance the possibility of occurrence of crisis of clinical brain edema (BE), which is the most important cause of morbidity and mortality in pediatric DKA. Longitudinal neurocognitive studies after DKA treatment show progressive and latent deficits of cognition and emphasize the need for more effective DKA treatment of this long-standing conundrum of clinical BE, in the presence of systemic osmotic dehydration, metabolic acidosis and immune dysregulation. Candidate biomarkers of several systemic and neuroinflammatory pathways prior to treatment also progress during treatment, such as the neurotoxic and neuroprotective molecules in the well-recognized tryptophan (TRP)/kynurenine pathway (KP) that have not been investigated in DKA. We used LC-MS/MS targeted mass spectrometry analysis to determine the presence and initiation of the TRP/KP at three time points: A) 6-12 hours after initiation of treatment; B) 2 weeks; and C) 3 months following DKA treatment to determine if they might be involved in the pathogenesis of the acute vasogenic complication of DKA/BE. The Trp/KP metabolites TRP, KYN, quinolinic acid (QA), xanthurnenic acid (XA), and picolinic acid (PA) followed a similar pattern of lower levels in early treatment, with subsequent increases. Time point A compared to Time points B and C were similar to the pattern of sRAGE, lactate and pyruvic acid. The serotonin/melatonin metabolites also followed a similar pattern of lower quantities at the early stages of treatment compared to 3 months after treatment. In addition, glutamate, n-acetylglutamate, glutamine, and taurine were all lower at early treatment compared to 3 months, while the ketones 3-hydroxybutaric acid and acetoacetate were significantly higher in the early treatment compared to 3 months. The two major fat metabolites, L-carnitine and acetyl-L-carnitine (ALC) changed inversely, with ALC significantly decreasing at 2 weeks and 3 months compared to the early stages of treatment. Both anthranilic acid (AA) and 3-OH-anthranilic acid (3OH-AA) had overall higher levels in the early stages of treatment (A) compared to Time points (B and C). Interestingly, the levels of AA and 3OH-AA early in treatment were higher in Caucasian females compared to African American females. There were also differences in the metabolite levels of QA and kynurenic acid (KA) between genders and between races that may be important for further development of custom targeted treatments. We hypothesize that the TRP/KP, along with the other inflammatory pathways, is an active participant in the metabolic and immunologic pathogenesis of DKA's acute and chronic insults.

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.

Soluble Receptor for Glycation End-products Concentration Increases Following the Treatment of Severe Diabetic Ketoacidosis

OBJECTIVE

To determine the time relationships of soluble receptor for glycation end-products (sRAGE), [a decoy of the advanced glycation end-products (AGE)-RAGE axis] and D-lactate, (a metabolite of methylglyoxal) in the inflammatory response to diabetic ketoacidosis (DKA).

METHODS

Sixteen children and adolescents with type 1 diabetes (T1D) had blood samples obtained, 6-12 hours into treatment, at three weeks and three months post start of treatment. sRAGE and D-lactate concentrations at three months were considered baseline. Expression of RAGE was investigated in the myocardium of a newly diagnosed and untreated young person with fatal T1D/DKA.

RESULTS

sRAGE 6-12 hours after the start of treatment was 39% lower than the values at two weeks (p=0.0036) and at three months (p=0.0023) post treatment. D-lactate was higher during treatment than at three weeks (p=0.04) and at three months (p=0.035).

CONCLUSION

sRAGE concentration was decreased during treatment, compared to concentrations at two weeks and three months after treatment. The increased D-lactate during treatment was in keeping with the known increase in dicarbonyls at this time. The finding of RAGE expression in a young myocardium prior to DKA treatment suggested cardiovascular inflammation pre-treatment and at a young age.

Intracerebral matrix metalloproteinase 9 in fatal diabetic ketoacidosis

There is increasing awareness that in addition to the metabolic crisis of diabetic ketoacidosis (DKA) caused by severe insulin deficiency, the immune inflammatory response is likely an active multicomponent participant in both the acute and chronic insults of this medical crisis, with strong evidence of activation for both the cytokine and complement system. Recent studies report that the matrix metalloproteinase enzymes and their inhibitors are systemically activated in young Type 1 diabetes mellitus (T1D) patients during DKA and speculate on their involvement in blood-brain barrier (BBB) disruption. Based on our previous studies, we address the question if matrix metalloproteinase 9 (MMP9) is expressed in the brain in the fatal brain edema (BE) of DKA. Our data show significant expression of MMP9 on the cells present in brain intravascular areas. The presence of MMP9 in intravascular cells and that of MMP+ cells seen passing the BBB indicates a possible role in tight junction protein disruption of the BBB, possibly leading to neurological complications including BE. We have also shown that MMP9 is expressed on neurons in the hippocampal areas of both BE/DKA cases investigated, while expression of tissue inhibitor of metalloproteinases 1 (TIMP1) was reduced in the same areas. We can speculate that intraneuronal MMP9 can be a sign of neurodegeneration. Further studies are necessary to determine the role of MMP9 in the pathogenesis of the neurologic catastrophe of the brain edema of DKA. Inhibition of MMP9 expression might be helpful in preserving neuronal function and BBB integrity during DKA.

Brain injury markers: S100 calcium-binding protein B, neuron-specific enolase and glial fibrillary acidic protein in children with diabetic ketoacidosis

BACKGROUND

To investigate serum levels of brain injury markers in diabetic ketoacidosis (DKA) and the relation of these markers with clinical and radiological findings of brain injury and laboratory results.

METHODS

Twenty-nine patients with DKA, 30 with type 1 diabetes mellitus (T1DM), and 35 healthy children were included. Clinical and laboratory findings, and the Glasgow Coma Scale (GCS) were recorded. In the DKA group, neuron-specific enolase (NSE), S100 calcium-binding protein B (S100B) and glial fibrillary acidic protein (GFAP) levels were measured at baseline and 6 and 12 hours after treatment. Magnetic resonance imaging was performed in the DKA group to demonstrate any brain injury.

RESULTS

No clinical or radiological findings of brain injury were found in any of the patients with DKA. In the DKA group, S100B was significantly higher than the healthy control and T1DM groups, while GFAP and NSE levels were not different from controls and T1DM patients. No significant differences were found in GFAP, NSE and S100B levels according to severity of DKA, diabetes duration and GCS.

CONCLUSION

NSE and GFAP levels do not increase in DKA patients without overt brain injury. Elevated levels of S100B, which is also synthesized from non-neuronal tissues, might arise from peripheral sources. A lack of concurrent increase in serum levels of these brain injury markers might result from the yet intact blood brain barrier or a true absence of neuronal damage. In order to reveal subclinical brain injury related to DKA, there is a need for studies concurrently assessing neurocognitive functions.

Presenting predictors and temporal trends of treatment-related outcomes in diabetic ketoacidosis

OBJECTIVE

This study examines temporal trends in treatment-related outcomes surrounding a diabetic ketoacidosis (DKA) performance improvement intervention consisting of mandated intensive care unit admission and implementation of a standardized management pathway, and identifies physical and biochemical characteristics associated with outcomes in this population.

METHODS

A retrospective cohort of 1225 children with DKA were identified in the electronic health record by international classification of diseases codes and a minimum pH less than 7.3 during hospitalization at a quaternary children's hospital between April, 2009 and May, 2016. Multivariable regression examined predictors and trends of hypoglycemia, central venous line placement, severe hyperchloremia, head computed tomography (CT) utilization, treated cerebral edema and hospital length of stay (LOS).

RESULTS

The incidence of severe hyperchloremia and head CT utilization decreased during the study period. Among patients with severe DKA (presenting pH < 7.1), the intervention was associated with decreasing LOS and less variability in LOS. Lower pH at presentation was independently associated with increased risk for all outcomes except hypoglycemia, which was associated with higher pH. Patients treated for cerebral edema had a lower presenting mean systolic blood pressure z score (0.58 [95% confidence interval (CI) -0.02-1.17] vs 1.23 [1.13-1.33]) and a higher maximum mean systolic blood pressure (SBP) z score during hospitalization (3.75 [3.19-4.31] vs 2.48 [2.38-2.58]) compared to patients not receiving cerebral edema treatment. Blood pressure and cerebral edema remained significantly associated after covariate adjustment.

CONCLUSION

Treatment-related outcomes improved over the entire study period and following a performance improvement intervention. The association of SBP with cerebral edema warrants further study.

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.

Markers of immune-mediated inflammation in the brains of young adults and adolescents with type 1 diabetes and fatal diabetic ketoacidosis. Is there a difference?

Due to the limited data on diabetic ketoacidosis and brain edema (DKA/BE) in children/adolescents and the lack of recent data on adults with type 1 diabetes (T1D), we addressed the question of whether neuroinflammation was present in the fatal DKA of adults. We performed immunohistochemistry (IHC) studies on the brains of two young adults with T1D and fatal DKA and compared them with two teenagers with poorly controlled diabetes and fatal DKA. C5b-9, the membrane attack complex (MAC) had significantly greater deposits in the grey and white matter of the teenagers than the young adults (p=0.03). CD59, a MAC assembly inhibitory protein was absent, possibly suppressed by the hyperglycemia in the teenagers but was expressed in the young adults despite comparable average levels of hyperglycemia. The receptor for advanced glycation end products (RAGE) had an average expression in the young adults significantly greater than in the teenagers (p=0.02). The autophagy marker Light Chain 3 (LC3) A/B was the predominant form of programmed cell death (PCD) in the teenage brains. The young adults had high expressions of both LC3A/B and TUNEL, an apoptotic cell marker for DNA fragmentation. BE was present in the newly diagnosed young adult with hyperglycemic hyperosmolar DKA and also in the two teenagers. Our data indicate that significant differences in neuroinflammatory components, initiated by the dysregulation of DKA and interrelated metabolic and immunologic milieu, are likely present in the brains of fatal DKA of teenagers when compared with young adults.

Emergency Medicine Myths: Cerebral Edema in Pediatric Diabetic Ketoacidosis and Intravenous Fluids

BACKGROUND

Pediatric diabetic ketoacidosis (DKA) is a disease associated with several complications that can be severe. One complication includes cerebral edema (CE), and patients may experience significant morbidity with this disease.

OBJECTIVE

This review evaluates the myths concerning CE in pediatric DKA including mechanism, presentation of edema, clinical assessment of dehydration, and association with intravenous (i.v.) fluids.

DISCUSSION

Multiple complications may occur in pediatric DKA. CE occurs in < 1% of pediatric DKA cases, though morbidity and mortality are severe without treatment. Several myths surround this disease. Subclinical CE is likely present in many patients with pediatric DKA, though severe disease is rare. A multitude of mechanisms likely account for development of CE, including vasogenic and cytotoxic causes. Clinical dehydration is difficult to assess. Literature has evaluated the association of fluid infusion with the development of CE, but most studies are retrospective, with no comparator groups. The few studies with comparisons suggest fluid infusion is not associated with DKA. Rather, the severity of DKA with higher blood urea nitrogen and greater acidosis contribute to CE. Multiple strategies for fluid replacement exist. A bolus of 10 mL/kg of i.v. fluid is likely safe, which can be repeated if hemodynamic status does not improve.

CONCLUSIONS

Pediatric CE in DKA is rare but severe. Multiple mechanisms result in this disease, and many patients experience subclinical CE. Intravenous fluids are likely not associated with development of CE, and 10-mL/kg or 20-mL/kg i.v. bolus is safe.

Statin Use and Cognitive Impairment in Patients With Type 1 Diabetes: An Observational Study

OBJECTIVE

We aimed to assess a wide range of cognitive functions in patients with type 1 diabetes (DM1) compared with healthy control subjects and to evaluate the effects of statins on cognitive functions in DM1 patients.

MATERIALS AND METHODS

The sample studied consisted of 55 DM1 patients (80.0% with hyperlipidemia, 20% with statin treatment) and 36 age-matched control subjects (77.8% with hyperlipidemia) without diabetes or statin use. Their cognitive functions (attention, memory, and executive functions) were evaluated with the trail making test, controlled oral word association test (COWAT), Rey-Osterrieth complex figure test, brain damage test (diagnosticum für cerebralschädigung, DCS), Wisconsin card sorting test (WCST), and digit span and block design tests from the revised Wechsler adult intelligence scale.

RESULTS

Cognitive performance was impaired in DM1 patients when compared with the control group with regard to semantic verbal fluency (COWAT_animals), visual learning (DCS), conceptual-level responses, executive functions (WCST random errors), and WCST trials to complete the first category. Subgroups of DM1 patients distinguished on the basis of statin therapy did not differ with regard to verbal fluency (COWAT_animals), visual learning (DCS), conceptual-level responses, executive functions (WCST random errors), and WCST trials to complete the first category. Multivariate analysis also does not show the impact of statin therapy on cognitive functioning regardless of the duration of education, microangiopathic evidence, the presence of hyperlipidemia, or antihypertensive therapy.

CONCLUSIONS

We find impairment of cognitive functions in DM1 patients when compared with control subjects without diabetes. However, we show neither the effect of statins nor the significant influence of metabolic control, microangiopathic complications, or the presence of hyperlipidemia on cognitive functions in DM1 patients.

Cardiac antibody production to self-antigens in children and adolescents during and following the correction of severe diabetic ketoacidosis

Diabetic cardiomyopathy (DC) is an independent phenotype of diabetic cardiovascular disease. The understanding of the pathogenesis of DC in young patients with type 1 diabetes (T1D) is limited. The cardiac insults of diabetic ketoacidosis (DKA) and progression of DC could include development of antibodies (Abs) to cardiac self-antigens (SAgs) such as: myosin (M), vimentin (V) and k-alpha 1 tubulin (Kα1T). The goal of this study is to determine if the insults of severe DKA and its inflammatory cascade are associated with immune responses to SAgs. Development of Abs to the SAgs were determined by an ELISA using sera collected at three time points in relation to severe DKA (pH < 7.2). Results demonstrate significant differences between the development of Abs to VIM and a previously reported diastolic abnormality (DA) during DKA and its treatment and a NDA group at 2-3 months post DKA (p = 0.0452). A significant association is present between T1D duration (<3 years) and Abs to Kα1T (p = 0.0134). Further, Abs to MYO and VIM are associated with inflammatory cytokines. We propose that severe DKA initiates the synthesis of Abs to cardiac SAgs that are involved in the early immunopathogenesis of DC in young patients with T1D.

Effects of Diabetic Ketoacidosis on Visual and Verbal Neurocognitive Function in Young Patients Presenting with New-Onset Type 1 Diabetes

OBJECTIVE

To evaluate the effects of diabetic ketoacidosis (DKA) on neurocognitive functions in children and adolescents presenting with new-onset type 1 diabetes.

METHODS

Newly diagnosed patients were divided into two groups: those with DKA and those without DKA (non-DKA). Following metabolic stabilization, the patients took a mini-mental status exam prior to undergoing a baseline battery of cognitive tests that evaluated visual and verbal cognitive tasks. Follow-up testing was performed 8-12 weeks after diagnosis. Patients completed an IQ test at follow-up.

RESULTS

There was no statistical difference between the DKA and non-DKA groups neither in alertness at baseline testing nor in an IQ test at follow-up. The DKA group had significantly lower baseline scores than the non-DKA group for the visual cognitive tasks of design recognition, design memory and the composite visual memory index (VMI). At follow-up, Design Recognition remained statistically lower in the DKA group, but the design memory and the VMI tasks returned to statistical parity between the two groups. No significant differences were found in verbal cognitive tasks at baseline or follow-up between the two groups. Direct correlations were present for the admission CO2 and the visual cognitive tasks of VMI, design memory and design recognition. Direct correlations were also present for admission pH and VMI, design memory and picture memory.

CONCLUSION

Pediatric patients presenting with newly diagnosed type 1 diabetes and severe but uncomplicated DKA showed a definite trend for lower cognitive functioning when compared to the age-matched patients without DKA.

Ghrelin inhibits high glucose-induced PC12 cell apoptosis by regulating TLR4/NF-κB pathway

Ghrelin has a protective effect on diabetic encephalopathy. To expound the protective mechanism, we investigated the effects of ghrelin on high glucose-induced cell apoptosis and intracellular signaling in cultured PC12, which is a suitable model for studying neuronal cell death. High glucose-induced PC12 apoptosis was significantly inhibited by co-treatment of ghrelin. Sustaining inflammatory response is one of the molecular mechanisms of diabetic encephalopathy and TLR4 signaling has close relationship with inflammatory response. But there is no report about the biologic role of toll-like receptor 4/nuclear factor-κB (TLR4/NF-κB) signaling in controlling high glucose-induced PC12 apoptosis by ghrelin. In this study, we found that TLR4/NF-κB pathway was activated by high glucose stimulation in PC12 and significantly alleviated by the co-treatment of ghrelin. From these findings, we made the conclusion that ghrelin could attenuate the symptoms of diabetic encephalopathy, which alleviates inflammatory reaction of diabetic encephalopathy by regulating TLR4/NF-κB pathway.

Ameliorative effect of saffron aqueous extract on hyperglycemia, hyperlipidemia, and oxidative stress on diabetic encephalopathy in streptozotocin induced experimental diabetes mellitus

Diabetic encephalopathy is one of the severe complications in patients with diabetes mellitus. Findings indicate that saffron extract has antioxidant properties but its underlying beneficial effects on diabetic encephalopathy were unclear. In the present study, the protective activities of saffron were evaluated in diabetic encephalopathy. Saffron at 40 and 80 mg/kg significantly increased body weight and serum TNF-α and decreased blood glucose levels, glycosylated serum proteins, and serum advanced glycation endproducts (AGEs) levels. Furthermore, significant increase in HDL and decrease (P<0.05) in cholesterol, triglyceride, and LDL were observed after 28 days of treatment. At the end of experiments, the hippocampus tissue was used for determination of glutathione content (GSH), superoxide dismutase (SOD), and catalase (CAT) activities. Furthermore, saffron significantly increased GSH, SOD, and CAT but remarkably decreased cognitive deficit, serum TNF-α, and induced nitric oxide synthase (iNOS) activity in hippocampus tissue. Our findings indicated that saffron extract may reduce hyperglycemia and hyperlipidemia risk and also reduce the oxidative stress in diabetic encephalopathy rats. This study suggested that saffron extract might be a promising candidate for the improvement of chemically induced diabetes and its complications.

Autophagy in the brains of young patients with poorly controlled T1DM and fatal diabetic ketoacidosis

Semi-quantitative neuroradiologic studies, quantitative neuron density studies and immunocytochemistry markers of oxidative stress and neuroinflammation indicate neuronal injury and deficits in young patients with chronic poorly controlled type 1 diabetes mellitus (T1DM). Present data suggest that pathogenesis of the neuronal deficits in young patients, who die as the result of diabetic ketoacidosis (DKA) and brain edema (BE), does not involve apoptosis, a prominent form of regulated cell death in many disease states. To further address this we studied mediators of macroautophagy, endoplasmic reticulum (ER) stress and apoptosis. In all areas studied we demonstrated increased levels of macroautophagy-associated proteins including light chain-3 (LC3) and autophagy related protein-4 (Atg4), as well as increased levels of the ER-associated glucose-regulated protein78/binding immunoglobulin protein (GRP78/BiP) in T1DM. In contrast, cleaved caspase-3 was rarely detected in any T1DM brain regions. These results suggest that chronic metabolic instability and oxidative stress may cause alterations in the autophagy-lysosomal pathway but not apoptosis, and macroautophagy-associated molecules may serve as useful candidates for further study in the pathogenesis of early neuronal deficits in T1DM.

Amyloid-beta transporter expression at the blood-CSF barrier is age-dependent

Background

Age is the major risk factor for many neurodegenerative diseases, including Alzheimer's disease (AD). There is an accumulation of amyloid-beta peptides (Aβ) in both the AD brain and the normal aging brain. Clearance of Aβ from the brain occurs via active transport at the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). With increasing age, the expression of the Aβ efflux transporters is decreased and the Aβ influx transporter expression is increased at the BBB, adding to the amyloid burden in the brain. Expression of the Aβ transporters at the choroid plexus (CP) epithelium as a function of aging was the subject of this study.

Methods

This project investigated the changes in expression of the Aβ transporters, the low density lipoprotein receptor-related protein-1 (LRP-1), P-glycoprotein (P-gp), LRP-2 (megalin) and the receptor for advanced glycation end-products (RAGE) at the BCSFB in Brown-Norway/Fischer rats at ages 3, 6, 9, 12, 20, 30 and 36 months, using real time RT-PCR to measure transporter mRNA expression, and immunohistochemistry (IHC) to measure transporter protein in isolated rat CP.

Results

There was an increase in the transcription of the Aβ efflux transporters, LRP-1 and P-gp, no change in RAGE expression and a decrease in LRP-2, the CP epithelium influx transporter, at the BCSFB with aging. Decreased Aβ42 concentration in the CP, as measured by quantitative IHC, was associated with these Aβ transporter alterations.

Conclusions

Age-dependent alterations in the CP Aβ transporters are associated with a decrease in Aβ42 accumulation in the CP, and are reciprocal to the changes seen in these transporters at the BBB, suggesting a possible compensatory role for the BCSFB in Aβ clearance in aging.

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.

Oxidative damage is present in the fatal brain edema of diabetic ketoacidosis

Oxidative stress is implicated as a pathogenic factor in a spectrum of chronic diseases, notably, neurodegenerative disease. Noteworthy in this regard is that type 1 diabetes mellitus (T1DM) results in oxidative stress, leading to systemic complications of T1DM. We hypothesized that oxidative stress associated with diabetic ketoacidosis (DKA) of T1DM might have measurable brain sequelae. Consistent with this hypothesis are neurohistology and neuroradiologic studies of T1DM that suggest oxidative insults are involved in the chronic complications of diabetic encephalopathy. To further address the role of oxidative stress in an acute setting, specifically in fatal brain edema (BE) associated with DKA, we studied neuronal localization and levels of oxidative stress markers reported to be increased in other neurodegenerative conditions. We demonstrated increased levels of 8-hydroxyguanosine (8OHG), 4-hydroxynonenal (HNE), and heme oxygenase-1 (HO-1) in the pyramidal neurons of the hippocampus of DKA BE in comparison to controls. However, in the cerebellum, only 8OHG was increased in the Purkinje cells and other cells of the molecular layer. These results indicate a role for oxidative stress in the pathogenesis of T1DM encephalopathy.

Insulin and IGF-1 receptors, nitrotyrosin and cerebral neuronal deficits in two young patients with diabetic ketoacidosis and fatal brain edema

Gray and white matter structural deficits may accompany type 1 diabetes. Earlier experimental studies have demonstrated neuronal deficits associated with impaired neurotrophic support, inflammation and oxidative stress. In this study we demonstrate in two patients with histories of poorly controlled type 1 diabetes and fatal brain edema of ketoacidosis neuronal deficits associated with a decreased presence of insulin and IGF-1 receptors and accumulation of nitrotyrosin in neurons of affected areas and the choroid plexus. The findings add support to the suggested genesis of T1DM encephalopathy due to compromised neurotrophic protection, oxidative stress, inflammation and neuronal deficits, as demonstrated in T1DM encephalopathy in the BB/Wor-rat.

Sequential abnormalities in type 1 diabetic encephalopathy and the effects of C-Peptide

Diabetic encephalopathy is a recently recognized complication in type 1 diabetes. In this review, we summarize a series of experimental results obtained longitudinally in the spontaneously type 1 diabetic BB/Wor-rat, and bringing out the beneficial effects of C-peptide replacement. It is increasingly clear that lack of insulin and C-peptide, and perturbations of their signaling cascades in type 1 diabetes are detrimental to the regulation of neurotrophic factors and their receptors. Other consequences of such deficits and perturbations are innate inflammatory responses with effects on synaptogenesis, neurite degeneration, and early behavioral abnormalities. Replacement of C-peptide, which does not effect hyperglycemia, has beneficial effects on a variety of pro-apoptotic stressors, oxidative stressors, and finally on apoptosis. Eventually, this cascade of events leads to neuronal loss and decreased densities of white matter myelinating cells, with more profound deficits in behavioral and cognitive function. Such changes are likely to underlie gray and white matter atrophy in type 1 diabetes, and are significantly prevented by full C-peptide replacement. Present data demonstrate that C-peptide replacement has beneficial effects on numerous sequential and partly interrelated pathogenetic mechanisms, resulting in prevention of neuronal and oligodendroglial cell loss, with significant prevention of neurobehavioral and cognitive functions.

Inflammation in Diabetic Encephalopathy is Prevented by C-Peptide

Encephalopathy is an increasingly recognized complication of type 1 diabetes. The underlying mechanisms are not well understood, although insulin deficiency has been implicated. The spontaneously diabetic BB/Wor-rat develops neuro-behavioral deficits and neuronal cell death in hippocampus and frontal cortex, which can be prevented by insulinomimetic C-peptide. Here we examined whether contributing factors such as activation of innate immune mediators are responsive to C-peptide replacement. Seven-month diabetic BB/Wor-rats and those treated with full C-peptide replacement were compared to age-matched control rats. Hippocampi of diabetic rats showed upregulation of RAGE and NF-kappaB, the former being localized to proliferating astrocytes. These changes were associated with increased expression of TNF-alpha, IL-1beta, IL-2 and IL-6 in hippocampi of diabetic rats. Full C-peptide replacement, which did not induce hyperglycemia, resulted in significant prevention of upregulation of RAGE expression, activation of NF-kappaB and activation of pro-inflammatory factors. In conclusion, impaired insulin activity is associated with upregulation of RAGE and pro-inflammatory factors, and these are likely to contribute to previously described oxidative and apoptotic neuronal cell death. Replacement of insulinomimetic C-peptide significantly prevents this cascade of events.