The Impact of Diabetes on Cerebral Structure and Function

Stem Cell Treatments in Preclinical Relevant Stroke Models

Since stroke has limited treatment options, an active search for new therapeutic approaches is required. Initial excitement of using cell-based therapies to stimulate recovery processes in the ischemic brain turned into a more measured perspective, acknowledging obstacles related to the unfavorable environments associated in part with aging. Given the predominance of stroke in older populations, evaluating the effectiveness of cell therapies in aged brain environments is essential and clinically relevant. Despite a common perception of the aged brain being resistant to regeneration, recent research with neural precursor cells and bone marrow-derived mesenchymal stem cells indicates that cell-based therapy can promote plasticity and remodeling in the aged rat brain. However, significant differences in the aged brain compared to the young brain, such as expedited progression of ischemic injury to brain infarction, decreased rate of endogenous neurogenesis, and delayed onset of neurological recovery, must be noted. The effectiveness of cell-based therapies may further be connected to age-related comorbidities such as diabetes or hyperlipidemia, potentially leading to maladaptive or impaired brain remodeling. These age-related factors need careful consideration in the clinical application of restorative therapies for stroke.

The ER chaperone, BIP protects Microglia from ER stress-mediated Apoptosis in Hyperglycemia

A major endoplasmic reticulum (ER) chaperone, binding of Immunoglobulin heavy chain protein (BIP) facilitates the assembly of newly synthesized proteins in the ER. Microglia vigorously respond to brain injuries and eliminate the damaged neuronal and apoptotic cells through phagocytosis in the central nervous system. However, the mechanism of BIP-mediated microglial function is not clear in hyperglycemia. We explored the molecular mechanism of BIP in microglial function during hyperglycemic conditions. Hyperglycemia was induced in mice by two consecutive intraperitoneal injections of streptozotocin (STZ 100/kg) and confirmed by measuring the blood glucose from day 2 to day 14. After 14 days of experimental hyperglycemia, mice were sacrificed and brains were collected for ER chaperone expression. In-vitro hyperglycemia was induced by exposing HMC3 cells to 25 mM glucose for 5 days and proteins involved in ER stress, apoptosis, and autophagy were analyzed. In hyperglycemic conditions, BIP protein expression was dramatically reduced in HMC3 cells, which led to increased apoptosis through the activation of CHOP and mitochondrial pro-apoptotic proteins (Bax, Bad, and cleaved caspase-3). The flow cytometry results indicate hyperglycemia-induced apoptosis and reactive oxygen species (ROS) production. Interestingly, the BIP inducer X restored the apoptosis in HMC3 cells by derepressing BIP expression and inhibiting ER stress. These results suggest that the ER chaperone BIP is required for the microglial function and protects from apoptosis in hyperglycemia. A better understanding of BIP's molecular mechanism and role in microglial function may contribute to developing novel therapies for microglia dysfunction-associated neurodegenerative diseases.

Exploratory Multisite MR Spectroscopic Imaging Shows White Matter Neuroaxonal Loss Associated with Complications of Type 1 Diabetes in Children

BACKGROUND AND PURPOSE

Type 1 diabetes affects over 200,000 children in the United States and is associated with an increased risk of cognitive dysfunction. Prior single-site, single-voxel MRS case reports and studies have identified associations between reduced NAA/Cr, a marker of neuroaxonal loss, and type 1 diabetes. However, NAA/Cr differences among children with various disease complications or across different brain tissues remain unclear. To better understand this phenomenon and the role of MRS in characterizing it, we conducted a multisite pilot study.

MATERIALS AND METHODS

In 25 children, 6-14 years of age, with type 1 diabetes across 3 sites, we acquired T1WI and axial 2D MRSI along with phantom studies to calibrate scanner effects. We quantified tissue-weighted NAA/Cr in WM and deep GM and modeled them against study covariates.

RESULTS

We found that MRSI differentiated WM and deep GM by NAA/Cr on the individual level. On the population level, we found significant negative associations of WM NAA/Cr with chronic hyperglycemia quantified by hemoglobin A1c (P < .005) and a history of diabetic ketoacidosis at disease onset (P < .05). We found a statistical interaction (P < .05) between A1c and ketoacidosis, suggesting that neuroaxonal loss from ketoacidosis may outweigh that from poor glucose control. These associations were not present in deep GM.

CONCLUSIONS

Our pilot study suggests that MRSI differentiates GM and WM by NAA/Cr in this population, disease complications may lead to neuroaxonal loss in WM in children, and deeper investigation is warranted to further untangle how diabetic ketoacidosis and chronic hyperglycemia affect brain health and cognition in type 1 diabetes.

Glycemic control level alters working memory neural dynamics in adults with type 2 diabetes

Poor glycemic control in type 2 diabetes has been associated with accentuated age-related cognitive decline, although the underlying neural mechanisms are not well understood. The current study sought to identify the impact of glycemic control on the neural dynamics serving working memory in adults with type 2 diabetes. Participants (n = 34, ages = 55-73) performed a working memory task while undergoing MEG. Significant neural responses were examined relative to poorer (A1c > 7.0%) or tighter glycemic control (A1c < 7.0%). Those with poorer glycemic control showed diminished responses within left temporal and prefrontal regions during encoding and showed diminished responses within right occipital cortex during maintenance but showed an enhanced activity in the left temporal, occipital, and cerebellar regions during maintenance. Notably, left temporal activity in encoding and left lateral occipital activity in maintenance significantly predicted performance on the task such that diminished temporal activity led to longer reaction times, which were driven by the poorer glycemic control group. Greater lateral occipital activity during maintenance was associated with both lower accuracy and longer reaction times across all participants. These findings suggest that glycemic control has a robust impact on the neural dynamics serving working memory, with distinct effects by subprocess (e.g. encoding vs. maintenance) and direct effects on behavior.

Voxel-based morphometry reveals the correlation between gray matter volume and serum P-tau-181 in type 2 diabetes mellitus patients with different HbA1c levels

Introduction

Emerging evidence suggested widespread decreased gray matter volume (GMV) and tau hyperphosphorylation were associated with type 2 diabetes mellitus (T2DM). Insulin resistance is one of the mechanisms of neuron degeneration in T2DM; it can decrease the activity of protein kinase B and increase the activity of glycogen synthesis kinase-3β, thus promoting the hyperphosphorylation of tau protein and finally leading to neuronal degeneration. However, the association between GMV and serum tau protein phosphorylated at threonine 181 (P-tau-181) in T2DM patients lacks neuroimaging evidence. We aimed to investigate the difference in brain GMV between T2DM patients with different glycated hemoglobin A1c (HbA1c) levels and healthy control (HC) subjects and the correlation between serum P-tau-181 and GMV in T2DM patients.

Methods

Clinical parameters, biochemical indicators, and MRI data were collected for 41 T2DM patients with high glycosylated hemoglobin level (HGL), 17 T2DM patients with normal glycosylated hemoglobin level (NGL), and 42 HC subjects. Voxel-based morphometry (VBM) method was applied to investigate GMV differences among groups, and multiple regression analysis was used to examine the correlation between serum P-tau-181 and GMV.

Results

Compared with HC subjects, the T2DM patients with HGL or NGL all showed significantly decreased GMV. Briefly, the GMV decreased in T2DM patients with HGL was mainly in the bilateral parahippocampal gyrus (PHG), right middle temporal gyrus (MTG), temporal pole (TPOmid), hippocampus (HIP), and left lingual gyrus. The GMV reduction in T2DM patients with NGL was in the right superior temporal gyrus (STG), and there was no significant difference in GMV between the two diabetic groups. The GMV values of bilateral PHG, right MTG, TPOmid, HIP, and STG can significantly (p < 0.0001) distinguish T2DM patients from HC subjects in ROC curve analysis. In addition, we found that serum P-tau-181 levels were positively correlated with GMV in the right superior and middle occipital gyrus and cuneus, and negatively correlated with GMV in the right inferior temporal gyrus in T2DM patients.

Conclusion

Our study shows that GMV atrophy can be used as a potential biological indicator of T2DM and also emphasizes the important role of P-tau-181 in diabetic brain injury, providing new insights into the neuropathological mechanism of diabetic encephalopathy.

Neurological Features and Their Association With Gender in Diabetes Mellitus Patients

Introduction Understanding the wide range of clinical signs and symptoms associated with diabetes mellitus (DM) is crucial because people with DM are frequently misdiagnosed, given incorrect care, or poorly controlled. Therefore, the purpose of this study was to evaluate the neurological symptoms associated with type 1 and type 2 DM patients with respect to patient gender. Methods This was a cross-sectional multicenter study that was conducted at different hospitals using a non-probability sampling method. The duration of the study was eight months, from January 2022 to August 2022. The study involved 525 type 1 and type 2 DM patients with an age range from 35 to 70 years. Demographic details such as age, gender, socioeconomic status, past medical history, presence of comorbidities, type, and duration of DM, and neurological features were recorded as frequencies and percentages. A Chi-square test was used to determine the association between neurological symptoms associated with type 1 and type 2 DM and gender. Results The study findings showed that of 525 diabetic patients, 210 (40.0%) were females and 315 (60.0%) were males. The mean male and female mean ages were 57.36±14.99 and 50.52±14.8 years, respectively, with a significant difference with respect to gender (p<0.001). The prevalence of neurological manifestations showed that irritability or mood swings were reported by most of the male 216 (68.6%) and 163 (77.6%) female diabetic patients, with a significant association noticed (p=0.022). Moreover, a significant association was observed between both genders in terms of swelling of feet, ankles, hands, and eyes (p=0.042), confusion or difficulty in concentration (p=0.040), burning pain in feet or legs (p=0.012), and muscular pain or cramps in legs or feet (p=0.016).  Conclusion This study concluded that the prevalence of neurological manifestations was high among diabetic patients. Most of the neurological symptoms were significantly more pronounced in female diabetic patients. Moreover, most of the neurological symptoms were associated with the type (type 2 DM) and duration of DM. The presence of hypertension, dyslipidemia, and smoking also influenced some neurological manifestations.

Differences in brain activity between normal and diabetic rats under isoflurane anesthesia: a resting-state functional MRI study

BACKGROUND

Altered neural activity based on the fractional amplitude of low-frequency fluctuations (fALFF) has been reported in patients with diabetes. However, whether fALFF can differentiate healthy controls from diabetic animals under anesthesia remains unclear. The study aimed to elucidate the changes in fALFF in a rat model of diabetes under isoflurane anesthesia.

METHODS

The first group of rats (n = 5) received a single intraperitoneal injection of 70 mg/kg streptozotocin (STZ) to cause the development of diabetes. The second group of rats (n = 7) received a single intraperitoneal injection of the same volume of solvent. Resting-state functional magnetic resonance imaging was used to assess brain activity at 4 weeks after STZ or solvent administration.

RESULTS

Compared to the healthy control animals, rats with diabetes showed significantly decreased fALFF in various brain regions, including the cingulate cortex, somatosensory cortex, insula, and striatum (all P < 0.05). The decreased fALFF suggests the aberrant neural activities in the diabetic rats. No regions were detected in which the control group had a lower fALFF than that in the diabetes group.

CONCLUSIONS

The results of this study demonstrated that the fALFF could be used to differentiate healthy controls from diabetic animals, providing meaningful information regarding the neurological pathophysiology of diabetes in animal models.

The distribution pattern of M2 and Adrenergicα2 receptors on inferior colliculi in male newborns of diabetic rats

AIMS

Despite the high prevalence of diabetes in the world, its possible effects throughut pregnancy on neonatal auditory nervous system development are still unknown. In the present research, maternal diabetes' impact on the M2 and Adrenergic_α2 receptors expression in the inferior colliculus (IC) of male newborn rats was investigated. Main methods Female rats were grouped into three: sham, insulin-treated diabetic, and diabetic. Diabetes was induced through streptozotocin (STZ) injection as one dose intraperitoneally (65 mg/kg). After mating and delivery, male rats were euthanized on P0, P7, and P14. Immunohistochemistry (IHC) was used to study the distribution pattern of receptors. Key findings The present study indicated that the expression of M2 receptors in the diabetic group was significantly increased in pairwise comparisons in the sham and diabetic treated with insulin groups (P<0.001, each). The highest M2 expression was for the diabetic group on P14 and the lowest one was for the sham group on P0. The Adrenergic_α2a receptors expression in the diabetic group was significantly reduced in pairwise comparisons in the sham and diabetic treated with insulin groups (P <0.001, each). The highest Adrenergic_α2a expression was for the sham group on P14 and the lowest one was for the diabetic group on P0. There was no significant difference between the sham and insulin groups regarding all receptors expression.

SIGNIFICANCE

This study demonstrated a time-dependent significant decrease in Adrenergic_α2a but a time-dependent significant increase in M2 receptors expression.

Diabetes Mellitus Manifests As Focal Dystonia

Diabetes is one of the most common chronic diseases affecting over 400 million patients worldwide, many of which are affected with devastating macrovascular and microvascular complications. Diabetes affects both the peripheral and the central nervous systems. One of the unusual effects of hyperglycemia is involuntary movement, termed hyperglycemia-induced involuntary movement (HIIM). Here, we present a case of a middle-aged woman with neck dystonia as the initial manifestation of type 2 diabetes. Achieving euglycemia with insulin alone resulted in complete resolution of the neck dystonia. 

A Comprehensive Review of Neuronal Changes in Diabetics

There has been an exponential rise in diabetes mellitus (DM) cases on a global scale. Diabetes affects almost every system of the body, and the nervous system is no exception. Although the brain is dependent on glucose, providing it with the energy required for optimal functionality, glucose also plays a key role in the regulation of oxidative stress, cell death, among others, which furthermore contribute to the pathophysiology of neurological disorders. The variety of biochemical processes engaged in this process is only matched by the multitude of clinical consequences resulting from it. The wide-ranging effects on the central and peripheral nervous system include, but are not limited to axonopathies, neurodegenerative diseases, neurovascular diseases, and general cognitive impairment. All language search was conducted on MEDLINE, COCHRANE, EMBASE, and GOOGLE SCHOLAR till September 2021. The following search strings and Medical Subject Headings (MeSH terms) were used: "Diabetes Mellitus," "CNS," "Diabetic Neuropathy," and "Insulin." We explored the literature on diabetic neuropathy, covering its epidemiology, pathophysiology with the respective molecular pathways, clinical consequences with a special focus on the central nervous system and finally, measures to prevent and treat neuronal changes. Diabetes is slowly becoming an epidemic, rapidly increasing the clinical burden on account of its wide-ranging complications. This review focuses on the neuronal changes occurring in diabetes such as the impact of hyperglycemia on brain function and structure, its association with various neurological disorders, and a few diabetes-induced peripheral neuropathic changes. It is an attempt to summarize the relevant literature about neuronal consequences of DM as treatment options available today are mostly focused on achieving better glycemic control; further research on novel treatment options to prevent or delay the progression of neuronal changes is still needed.

A multimodal meta-analysis of regional structural and functional brain alterations in type 2 diabetes

Neuroimaging studies have identified brain structural and functional alterations of type 2 diabetes mellitus (T2DM) patients; however, there is no systematic information on the relations between abnormalities in these two domains. We conducted a multimodal meta-analysis of voxel-based morphometry and regional resting-state functional MRI studies in T2DM, including fifteen structural datasets (693 patients and 684 controls) and sixteen functional datasets (378 patients and 358 controls). We found, in patients with T2DM compared to controls, conjoint decreased regional gray matter volume (GMV) and altered intrinsic activity mainly in the default mode network including bilateral superior temporal gyrus/Rolandic operculum, left middle and inferior temporal gyrus, and left supramarginal gyrus; decreased GMV alone in the limbic system; and functional abnormalities alone in the cerebellum, insula, and visual cortex. This meta-analysis identified complicated patterns of conjoint and dissociated brain alterations in T2DM patients, which may help provide new insight into the neuropathology of T2DM.

Effects of berberine on cholinesterases and monoamine oxidase activities, and antioxidant status in the brain of streptozotocin (STZ)-induced diabetic rats

OBJECTIVES

Several studies had been conducted to examine the link between diabetes and diabetes encephalopathy. This study was conducted to examine the potency of berberine (BER) on the restoration of impaired neurochemicals in the brain of streptozotocin (STZ)-induced diabetic Wistar rats.

METHODS

Fifty-six (56) adult rats weighing between 200 and 230 g were randomly divided into seven groups (n=8) as follows; Group I is normal control; Groups II and III were normal rats treated with 50 and 100 mg/kg respectively; Group IV-VII were STZ-induced rats, but Groups V-VII were treated with acarbose (25 mg/kg), 50 and 100 mg/kg of BER, respectively.

RESULTS

The result of the study showed that untreated STZ-induced diabetic rats have increased acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO) activities, and malonylaldehyde (MDA) level, with concomitant decrease of superoxide dismutase (SOD), glutathione peroxidase (GPx) activities, and glutathione (GSH) level. However, daily treatment with 50 and 100 mg/kg BER and ACA significantly reversed these effects.

CONCLUSIONS

The findings of this study clearly indicated that BER possesses neuro-protective and antioxidative potentials and normalize neurochemical impairment distort by diabetes.

Brain functions and cognition on transient insulin deprivation in type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is a risk factor for dementia and structural brain changes. It remains to be determined whether transient insulin deprivation that frequently occurs in insulin-treated individuals with T1D alters brain function.

METHODS

We therefore performed functional and structural magnetic resonance imaging, magnetic resonance spectroscopy, and neuropsychological testing at baseline and following 5.4 ± 0.6 hours of insulin deprivation in 14 individuals with T1D and compared results with those from 14 age-, sex-, and BMI-matched nondiabetic (ND) participants with no interventions.

RESULTS

Insulin deprivation in T1D increased blood glucose, and β-hydroxybutyrate, while reducing bicarbonate levels. Participants with T1D showed lower baseline brain N-acetyl aspartate and myo-inositol levels but higher cortical fractional anisotropy, suggesting unhealthy neurons and brain microstructure. Although cognitive functions did not differ between participants with T1D and ND participants at baseline, significant changes in fine motor speed as well as attention and short-term memory occurred following insulin deprivation in participants with T1D. Insulin deprivation also reduced brain adenosine triphosphate levels and altered the phosphocreatine/adenosine triphosphate ratio. Baseline differences in functional connectivity in brain regions between participants with T1D and ND participants were noted, and on insulin deprivation further alterations in functional connectivity between regions, especially cortical and hippocampus-caudate regions, were observed. These alterations in functional connectivity correlated to brain metabolites and to changes in cognition.

CONCLUSION

Transient insulin deprivation therefore caused alterations in executive aspects of cognitive function concurrent with functional connectivity between memory regions and the sensory cortex. These findings have important clinical implications, as many patients with T1D inadvertently have periods of transient insulin deprivation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03392441.

FUNDING

Clinical and Translational Science Award (UL1 TR002377) from the National Center for Advancing Translational Science; NIH grants (R21 AG60139 and R01 AG62859); the Mayo Foundation.

A Prospective Study: Highlights of Hippocampal Spectroscopy in Cognitive Impairment in Patients with Type 1 and Type 2 Diabetes

Diabetes mellitus type 1 and 2 is associated with cognitive impairment. Previous studies have reported a relationship between changes in cerebral metabolite levels and the variability of glycemia. However, the specific risk factors that affect the metabolic changes associated with type 1 and type 2 diabetes in cognitive dysfunction remain uncertain. The aim of the study was to evaluate the specificity of hippocampal spectroscopy in type 1 and type 2 diabetes and cognitive dysfunction.

MATERIALS AND METHODS

65 patients with type 1 diabetes with cognitive deficits and 20 patients without, 75 patients with type 2 diabetes with cognitive deficits and 20 patients without have participated in the study. The general clinical analysis and evaluation of risk factors of cognitive impairment were carried out. Neuropsychological testing included the Montreal Scale of Cognitive Dysfunction Assessment (MoCA test). Magnetic resonance spectroscopy (MRS) was performed in the hippocampal area, with the assessment of N-acetylaspartate (NAA), choline (Cho), creatine (Cr), and phosphocreatine (PCr) levels. Statistical processing was performed using the commercially available IBM SPSS software.

RESULTS

Changes in the content of NAA, choline Cho, phosphocreatine Cr2 and their ratios were observed in type 1 diabetes. More pronounced changes in hippocampal metabolism were observed in type 2 diabetes for all of the studied metabolites. Primary risk factors of neurometabolic changes in patients with type 1 diabetes were episodes of severe hypoglycemia in the history of the disease, diabetic ketoacidosis (DKA), chronic hyperglycemia, and increased body mass index (BMI). In type 2 diabetes, arterial hypertension (AH), BMI, and patient's age are of greater importance, while the level of glycated hemoglobin (HbA1c), duration of the disease, level of education and insulin therapy are of lesser importance.

CONCLUSION

Patients with diabetes have altered hippocampal metabolism, which may serve as an early predictive marker. The main modifiable factors have been identified, correction of which may slow down the progression of cognitive dysfunction.

Intranasal Insulin for Alzheimer's Disease

Brain insulin signaling contributes to memory function and might be a viable target in the prevention and treatment of memory impairments including Alzheimer's disease. This short narrative review explores the potential of central nervous system (CNS) insulin administration via the intranasal pathway to improve memory performance in health and disease, with a focus on the most recent results. Proof-of-concept studies and (pilot) clinical trials in individuals with mild cognitive impairment or Alzheimer's disease indicate that acute and prolonged intranasal insulin administration enhances memory performance, and suggest that brain insulin resistance is a pathophysiological factor in Alzheimer's disease with or without concomitant metabolic dysfunction. Intranasally administered insulin is assumed to trigger improvements in synaptic plasticity and regional glucose uptake as well as alleviations of Alzheimer's disease neuropathology; additional contributions of changes in hypothalamus-pituitary-adrenocortical axis activity and sleep-related mechanisms are discussed. While intranasal insulin delivery has been conclusively demonstrated to be effective and safe, the recent outcomes of large-scale clinical studies underline the need for further investigations, which might also yield new insights into sex differences in the response to intranasal insulin and contribute to the optimization of delivery devices to grasp the full potential of intranasal insulin for Alzheimer's disease.

Increased cerebral FDG-PET uptake in type 1 diabetes patients with impaired awareness of hypoglycaemia

Approximately 20% of type 1 diabetes (T1D) patients have an impaired awareness of hypoglyceamia (IAH). IAH represents a risk factor for severe and recurrent hypoglycaemic events, which can lead to brain damage. Because no effective treatments are currently available to prevent IAH in this population, characterising the set of brain alterations associated with IAH may reveal novel preclinical diagnostic or therapeutic strategies. Using state-of-the art neuroimaging techniques, we compared ¹⁸ F-fluorodeoxyglucose-positron emission tomography (FDG-PET) uptake at rest between 10 T1D patients with IAH and nine patients with normal awareness of hypoglycaemia (NAH). T1D-IAH patients showed a pattern of increased FDG-PET uptake with respect to NAH patients (P < .05 corrected). Topographically, glucose metabolism was increased in the frontal and precuneus regions. Importantly, within the IAH group, this abnormal hypermetabolism correlated with IAH severity. This hypermetabolic state appeared to be unrelated to compensatory mechanisms as a result of reduced grey matter density or a neuroinflammatory state. We observed an abnormal increase in FDG-uptake in T1D patients with IAH in brain regions strongly related to cognition. Because this hypermetabolic state correlated with IAH severity, its biological characterisation could reveal new preventive or therapeutic strategies. A possible mechanism could be that glucose transport is increased in hypoglycaemia unawareness to compensate for recurrent hypoglycaemia, although this need to be confirmed in further research.

A Case Report of Nonketotic Hyperglycemic Seizures: A Diagnostic Dilemma

Nonketotic hyperglycemia (NKH) is a rare but serious complication of uncontrolled diabetes mellitus that occurs acutely with a mortality rate of more than 50%. This condition presents with a clinical syndrome consisting of profound hyperglycemia, hyperosmolality, and dehydration. Infrequently, the patients also present with seizure activity. The most common types of seizures observed in this condition are focal seizures, as opposed to the generalized seizures observed in hypoglycemia-induced seizures. Though various hypotheses tried to explain NKH-induced seizure activity, the actual mechanism remains unknown. The treatment modalities include the management of hyperglycemia and circulatory collapse. However, the role of anti-epileptics is controversial. We herein illustrate an atypical case of focal faciobrachial seizures in a young female patient, which occurred as a rare complication of NKH. A 21-year-old female was admitted with multiple jerking and spasmodic movements of the right upper limb and face, with no significant neurological findings. Past medical history was significant for uncontrolled type 2 diabetes mellitus and multiple episodes of focal seizures. On laboratory examination, serum osmolarity was 309 mOsm/L, blood glucose was 364 mg/dL, HbA1c was 12.1%, and ketone bodies were absent. MRI brain showed large subtle T2 FLAIR (T2-weighted fluid-attenuated inversion recovery) cortical hyperintensities in the left frontal, temporal, parietal, and occipital regions with subcortical hypointense areas. The EEG illustrated a background slowing and generalized spikes, polyspikes, and sharp-wave discharges with post-ictal slowing. The patient's seizures were initially refractory to insulin therapy and resolved with the use of dual anti-epileptics. Thus, to conclude, our case represents a diagnostic dilemma with MRI findings pointing towards NKH as the underlying etiology of focal seizures, with the resolution of seizures only occurring with the addition of anti-epileptics to insulin therapy.

The neurometabolic profiles of GABA and Glutamate as revealed by proton magnetic resonance spectroscopy in type 1 and type 2 diabetes

Glucose metabolism is pivotal for energy and neurotransmitter synthesis and homeostasis, particularly in Glutamate and GABA systems. In turn, the stringent control of inhibitory/excitatory tonus is known to be relevant in neuropsychiatric conditions. Glutamatergic neurotransmission dominates excitatory synaptic functions and is involved in plasticity and excitotoxicity. GABAergic neurochemistry underlies inhibition and predicts impaired psychophysical function in diabetes. It has also been associated with cognitive decline in people with diabetes. Still, the relation between metabolic homeostasis and neurotransmission remains elusive.

Two 3T proton MR spectroscopy studies were independently conducted in the occipital cortex to provide insight into inhibitory/excitatory homeostasis (GABA/Glutamate) and to evaluate the impact of chronic metabolic control on the levels and regulation (as assessed by regression slopes) of the two main neurotransmitters of the CNS in type 2 diabetes (T2DM) and type 1 diabetes (T1DM).

Compared to controls, participants with T2DM showed significantly lower Glutamate, and also GABA. Nevertheless, higher levels of GABA/Glx (Glutamate+Glutamine), and lower levels of Glutamate were associated with poor metabolic control in participants with T2DM. Importantly, the relationship between GABA/Glx and HbA_1c found in T2DM supports a relationship between inhibitory/excitatory balance and metabolic control. Interestingly, this neurometabolic profile was undetected in T1DM. In this condition we found strong evidence for alterations in MRS surrogate measures of neuroinflammation (myo-Inositol), positively related to chronic metabolic control.

Our results suggest a role for Glutamate as a global marker of T2DM and a sensitive marker of glycemic status. GABA/Glx may provide a signature of cortical metabolic state in poorly controlled patients as assessed by HbA_1c levels, which indicate long-term blood Glucose control. These findings are consistent with an interplay between abnormal neurotransmission and metabolic control in particular in type 2 diabetes thereby revealing dissimilar contributions to the pathophysiology of neural dysfunction in both types of diabetes.

Frequency of Abnormal Glucose Tolerance Test Suggestive of Dumping Syndrome Following Oesophageal Atresia Repair

OBJECTIVES

Dumping syndrome (DS) is mostly described as a complication of antireflux surgery in oesophageal atresia (OA) but we previously reported 2 cases of DS before any other surgery in infants operated at birth for OA. The objectives of the present study were to assess the prevalence of abnormal oral glucose tolerance test (OGTT) at 3 months of age in infants operated at birth with type C OA, to describe symptoms and clinical features, and to assess risk factors in infants presenting with abnormal OGTT suggestive of DS.

METHODS

A prospective case series study including infants with type C OA without fundoplication, born between 2013 and 2016 in 8 centres was conducted. An OGTT was performed between 2.5 and 3.5 months. Abnormal OGTT was defined as early hyperglycaemia (>1.8 g/L until 30 minutes; >1.7 g/L between 30 minutes and 2 hours; and >1.4 g/L between 2 and 3 hours) and/or late hypoglycaemia (<0.6 g/L after 2 hours).

RESULTS

Eleven of the 38 OGTT (29%) showed abnormalities. None of the patients' demographics (birth weight, sex, prematurity, associated malformation, use of enteral nutrition) or conditions of the surgery tested was associated with abnormal OGTT. No clinical sign was specific for it.

CONCLUSIONS

DS should be considered in every infant operated at birth for OA presenting with digestive symptoms. No risk factor was predictive for abnormal OGTT. An OGTT to screen for potential DS around 3 months of age should be considered in infants born with EA.

CLINICAL TRIAL NAME AND REGISTRATION NUMBER

DUMPING NCT02525705.

The impact of white matter hyperintensities on speech perception

BACKGROUND

The presence of white matter hyperintensities (WMHs) can impact on normal brain function by altering normal signal transmission and determining different symptoms.

AIM

To evaluate the relationship between the presence of brain WMHs and the scores of speech perception test (SPT) in a sample of normal-hearing patients under 70 years of age.

MATERIAL AND METHOD

Prospective study. One hundred eleven patients underwent audiological screening with pure tone audiometry (PTA), tympanometry, speech perception testing (SPT), and brain magnetic resonance imaging (MRI). T2 sequences were analyzed to identify the presence of WMH that, if identified, were scored using the Fazekas score. Statistical multiple regression analysis was performed to understand the relationship between PTA and SPT score; the Pearson's and Spearman's tests were used to evaluate the correlation between Fazekas scores and SPT. Chi-square test was used to analyze the difference between gender.

RESULTS

The results of PTA were not predictive of the SPT score. A negative statistically significant correlation (Spearman's, p = 0.0001; Pearson's, p < 0.001) was identified between the Fazekas score and the results of SPT. No statistically significant differences were identified in the correlation of WMH and SPT between males and females.

CONCLUSION

Multiple WMHs in the brain can worsen word recognition in patients with normal auditory threshold; this may be related to the impact that these lesions have on the memory ability. Spread of lesions into the brain might reduce the brain capacity to remember words, despite the sound is correctly perceived by the ear.

Complications of type 1 diabetes melitus in children

The World Health Organization has defined Diabetes mellitus as a disorder of metabolism of various causes, due to lack of secretion and / or action of insulin, with long-term hyperglycemia and altered metabolism of sugars, proteins and fats. Diabetes mellitus is the most widespread chronic non-infectious disease, with an increase in the frequency in childhood that could be the epidemic of the 21st century. The incidence is rapidly increasing in the world, while in the last thirty years in Serbia there has been an increase in the number of patients - especially in the group of small and preschool children. Exposure to the genetic, immune and environmental factors plays an important role in the etiology of the disease, but the underlying mechanisms remain unknown. Weeks before the final diagnosis, weakness, irresistible hunger, weight loss, increased thirst, pronounced diuresis, drying of the mucous membranes, skin pruritus and blurred vision could be present. Inadequate glycemic control and unregulated lipid status of children with type 1 diabetes are compatible with numerous complications and a higher risk of cardiovascular, peripheral vascular and cerebrovascular diseases. The therapy consists of insulin therapy, adequate daily physical activity, a variety of diets, overcoming stressful life situations and maintaining satisfactory metabolic control. By using intensive insulin therapy, the best control of the disease is achieved, while the frequency of possible complications is reduced.

Overexpression of calcitonin gene-related peptide protects mouse cerebral microvascular endothelial cells from high-glucose-induced damage via ERK/HIF-1/VEGF signaling

In the diabetic brain, hyperglycemia damages the cerebrovasculature and impairs neurovascular crosstalk. Calcitonin gene-related peptide (CGRP) is an important neuropeptide that is active in the vascular system. In this study, we aimed to investigate whether CGRP is involved in the high-glucose-induced damage in mouse cerebral microvascular endothelial (b.END3) cells and the possible mechanism in vitro. The overexpression of CGRP by lentiviral transduction inhibited cell apoptosis but not proliferation. In contrast to the promoting of angiogenesis and migration under normal glucose, CGRP inhibited hyperglycemia-induced tube formation but had no effect on migration. Calcitonin gene-related peptide partly reduced the increased level of intracellular reactive oxygen species (ROS) and altered nitric oxide synthase mRNA expression. Furthermore, CGRP suppressed the increased HIF-1α/VEGF-A expression and the phosphorylation of ERK1/2 in hyperglycemia. The ERK inhibitor U0126 showed similar inhibition of cell apoptosis, tube formation and HIF-1α/VEGF expression as that exhibited by lenti-CGRP. These findings demonstrate the protective role of CGRP overexpression against high-glucose-induced cerebrovascular changes in b.END3 cells, possibly through the inhibition of ERK/HIF-1/VEGF signaling.

Sweet Mitochondria: A Shortcut to Alzheimer's Disease

A growing body of evidence supports a clear association between Alzheimer's disease and diabetes and several mechanistic links have been revealed. This paper is mainly devoted to the discussion of the role of diabetes-associated mitochondrial defects in the pathogenesis of Alzheimer's disease. The research experience and views of the author on this subject will be highlighted.

Basal ganglia cerebral blood flow associates with psychomotor speed in adults with type 1 diabetes

Type 1 diabetes is associated with slower psychomotor speed, but the neural basis of this relationship is not yet understood. The basal ganglia are a set of structures that are vulnerable to small vessel disease, particularly in individuals with type 1 diabetes. Thus, we examined the relationship between psychomotor speed and resting state resting cerebral blood flow in a sample of adults with diabetes onset during childhood (≤ 17 years of age). The sample included 77 patients (39 M, 38 F) with a mean age of 47.43 ± 5.72 years, age of onset at 8.50 ± 4.26 years, and duration of disease of 38.92 ± 4.18 years. Resting cerebral blood flow was quantified using arterial spin labeling. After covarying for sex, years of education and normalized gray matter volume, slower psychomotor speed was associated with lower cerebral blood flow in bilateral caudate nucleus-thalamus and a region in the superior frontal gyrus. These results suggest that the basal ganglia and frontal cortex may underlie slower psychomotor speed in individuals with type 1 diabetes.

Outcomes and clinical implications of intranasal insulin administration to the central nervous system

Insulin signaling in the brain plays a critical role in metabolic control and cognitive function. Targeting insulinergic pathways in the central nervous system via peripheral insulin administration is feasible, but associated with systemic effects that necessitate tight supervision or countermeasures. The intranasal route of insulin administration, which largely bypasses the circulation and thereby greatly reduces these obstacles, has now been repeatedly tested in proof-of-concept studies in humans as well as animals. It is routinely used in experimental settings to investigate the impact on eating behavior, peripheral metabolism, memory function and brain activation of acute or long-term enhancements in central nervous system insulin signaling. Epidemiological and experimental evidence linking deteriorations in metabolic control such as diabetes with neurodegenerative diseases imply pathophysiological relevance of dysfunctional brain insulin signaling or brain insulin resistance, and suggest that targeting insulin in the brain holds some promise as a therapy or adjunct therapy. This short narrative review gives an overview over recent findings on brain insulin signaling as derived from human studies deploying intranasal insulin, and evaluates the potential of therapeutic interventions that target brain insulin resistance.

Type 1 diabetes

Type 1 diabetes is a chronic autoimmune disease characterised by insulin deficiency and resultant hyperglycaemia. Knowledge of type 1 diabetes has rapidly increased over the past 25 years, resulting in a broad understanding about many aspects of the disease, including its genetics, epidemiology, immune and β-cell phenotypes, and disease burden. Interventions to preserve β cells have been tested, and several methods to improve clinical disease management have been assessed. However, wide gaps still exist in our understanding of type 1 diabetes and our ability to standardise clinical care and decrease disease-associated complications and burden. This Seminar gives an overview of the current understanding of the disease and potential future directions for research and care.

A Systematic Review and Meta-analysis of Executive Function Performance in Type 1 Diabetes Mellitus

OBJECTIVE

The aims of the study were to examine the current evidence for executive function (EF) performance differences between groups with type 1 diabetes mellitus (T1DM) and nondiabetic control groups during adolescence and early adulthood and to explore the relationships between EF and diabetes-related risk factors.

METHODS

A systematic review of the literature examining EF performance in groups with T1DM was conducted according to the PRISMA guidelines. Electronic database searches for published and unpublished literature yielded a final set of 26 articles after application of inclusion and exclusion criteria. A meta-analysis was conducted on a subset of these articles (n = 17) comparing EF performance in T1DM and control groups, across a total sample size of 1619.

RESULTS

Sixteen of 26 studies found significantly lower EF on at least one task in groups with T1DM. Meta-analyses of the performance difference between T1DM groups and control groups without diabetes showed that inhibition (g = -0.28, p < .001), working memory (g = -0.34, p < .001), set-shifting (g = -0.31, p = .012), and overall EF performance across these domains (g = -0.42, p < .001) were all significantly lower in groups with T1DM. Performance on specific EF domains also seemed to be differentially associated with early age of diabetes onset, chronic hyperglycemia and its complications, and severe hypoglycemia.

CONCLUSIONS

T1DM and its associated risk factors are related to subtle impairments across the inhibition, working memory, and set-shifting domains of EF. Lower EF may be a key factor contributing to behavioral and clinical problems experienced by individuals with T1DM.

Midlife Metabolic Profile and the Risk of Late-Life Cognitive Decline

Among metabolic syndrome components, the effects of higher plasma glucose levels on cognitive decline (CD) have been considered in few studies. We evaluated the associations among midlife glycemia, total cholesterol, high-density lipoprotein cholesterol, triglycerides, midlife insulin resistance [homeostasis model assessment for insulin resistance (HOMA-index)], and CD in the older subjects of the population-based MICOL Study (Castellana Grotte, Italy) at baseline (M1) and at follow-ups seven (M2) and twenty years later (M3). At M1, a dementia risk score and a composite cardiovascular risk score for dementia were calculated. For 797 subjects out of 833, we obtained a Mini-Mental State Examination (MMSE) score at M3, subdividing these subjects in three cognitive functioning subgroups: normal cognition, mild CD, and moderate-severe CD. Mean fasting glycemia at baseline was significantly higher in moderate-severe CD subgroup (114.6±71.4 mg/dl) than in the normal cognition subgroup (101.2±20.6). Adjusting for gender, age, and other metabolic components, higher fasting glycemia values both at M1 [odds ratio (OR) = 1.31; 95% confidence interval (CI): 1.08-1.59] and M2 (OR = 1.26; 95% CI: 1.01-1.57) were associated with an increased risk of moderate-severe CD. Mean HOMA index value was significantly higher in the moderate-severe CD subgroup (5.7±9.4) compared to the normal cognition subgroup (2.9±1.4) at M1. The dementia risk probability (MMSE < 24) increased moving through higher categories of the dementia risk score and decreased as long as the cardiovascular score increased. The present findings highlighted the indication to control blood glucose levels, regardless of a diagnosis of diabetes mellitus, as early as midlife for prevention of late-life dementia.

Neonatal hyperglycemia induces CXCL10/CXCR3 signaling and microglial activation and impairs long-term synaptogenesis in the hippocampus and alters behavior in rats

BACKGROUND

Hyperglycemia is common in extremely low gestational age newborns (ELGAN) and is associated with increased mortality and morbidity, including abnormal neurodevelopment. Hippocampus-mediated cognitive deficits are common in this population, but the specific effects of hyperglycemia on the developing hippocampus are not known.

METHODS

The objective of this study was to determine the acute and long-term effects of hyperglycemia on the developing hippocampus in neonatal rats using a streptozotocin (STZ)-induced model of hyperglycemia. STZ was injected on postnatal day (P) 2, and littermates in the control group were injected with an equivalent volume of citrate buffer. The acute effects of hyperglycemia on markers of oxidative stress, inflammatory cytokines, microglial activation, and reactive astrocytosis in the hippocampus were determined in the brain tissue collected on P6. The long-term effects on hippocampus-mediated behavior and hippocampal dendrite structure were determined on P90.

RESULTS

On P6, the transcript and protein expression of markers of oxidative stress and inflammatory cytokines, including the CXCL10/CXCR3 pathway, were upregulated in the hyperglycemia group. Histological evaluation revealed microglial activation and astrocytosis. The long-term assessment on P90 demonstrated abnormal performance in Barnes maze neurobehavioral testing and altered dendrite structure in the hippocampus of formerly hyperglycemic rats.

CONCLUSIONS

Neonatal hyperglycemia induces CXCL10/CXCR3 signaling, microglial activation, and astrocytosis in the rat hippocampus and alters long-term synaptogenesis and behavior. These results may explain the hippocampus-specific cognitive deficits common in ELGAN who experience neonatal hyperglycemia.

Thinking About Cognitive Function: Perceptions of Cognitive Changes in People With Type 2 Diabetes

Purpose The purpose of this study is 2-fold: (1) to explore how people with diabetes view diabetes-related cognitive problems and (2) to examine participants' ideas on a cognitive rehabilitation intervention to adapt it for persons diagnosed with type 2 diabetes (T2DM). Methods A qualitative descriptive study based on narrative interviews was conducted with adults (n = 10) with T2DM. The interview data were analyzed using content analysis. Results The interviews reflected 4 major themes: search for advice regarding cognitive complaints, cognitive symptoms, impact of perceived cognitive dysfunction on diabetes self-management, and maintenance of cognitive health. Specific areas of interest for an intervention included the following: understanding how cognitive function relates to diabetes, dealing with cognitive barriers to self-management, and learning how to incorporate a "brain healthy" lifestyle into daily activities. Conclusions Findings showed that perceived cognitive impairment impacted self-management and suggested that cognitive rehabilitation interventions have potential utility for people with T2DM. Existing successful interventions can be tailored to meet the needs of those whose diabetes self-management is impacted by cognitive problems.

Conditioned Medium of Human Adipose Mesenchymal Stem Cells Increases Wound Closure and Protects Human Astrocytes Following Scratch Assay In Vitro

Astrocytes perform essential functions in the preservation of neural tissue. For this reason, these cells can respond with changes in gene expression, hypertrophy, and proliferation upon a traumatic brain injury event (TBI). Different therapeutic strategies may be focused on preserving astrocyte functions and favor a non-generalized and non-sustained protective response over time post-injury. A recent strategy has been the use of the conditioned medium of human adipose mesenchymal stem cells (CM-hMSCA) as a therapeutic strategy for the treatment of various neuropathologies. However, although there is a lot of information about its effect on neuronal protection, studies on astrocytes are scarce and its specific action in glial cells is not well explored. In the present study, the effects of CM-hMSCA on human astrocytes subjected to scratch assay were assessed. Our findings indicated that CM-hMSCA improved cell viability, reduced nuclear fragmentation, and preserved mitochondrial membrane potential. These effects were accompanied by morphological changes and an increased polarity index thus reflecting the ability of astrocytes to migrate to the wound stimulated by CM-hMSCA. In conclusion, CM-hMSCA may be considered as a promising therapeutic strategy for the protection of astrocyte function in brain pathologies.

The diabetic brain and cognition

The prevalence of both Alzheimer's disease (AD) and vascular dementia (VaD) is increasing with the aging of the population. Studies from the last several years have shown that people with diabetes have an increased risk for dementia and cognitive impairment. Therefore, the authors of this consensus review tried to elaborate on the role of diabetes, especially diabetes type 2 (T2DM) in both AD and VaD. Based on the clinical and experimental work of scientists from 18 countries participating in the International Congress on Vascular Disorders and on literature search using PUBMED, it can be concluded that T2DM is a risk factor for both, AD and VaD, based on a pathology of glucose utilization. This pathology is the consequence of a disturbance of insulin-related mechanisms leading to brain insulin resistance. Although the underlying pathological mechanisms for AD and VaD are different in many aspects, the contribution of T2DM and insulin resistant brain state (IRBS) to cerebrovascular disturbances in both disorders cannot be neglected. Therefore, early diagnosis of metabolic parameters including those relevant for T2DM is required. Moreover, it is possible that therapeutic options utilized today for diabetes treatment may also have an effect on the risk for dementia. T2DM/IRBS contribute to pathological processes in AD and VaD.

Regional Gray Matter Volumes as Related to Psychomotor Slowing in Adults with Type 1 Diabetes

OBJECTIVE

Psychomotor slowing is a common cognitive complication in type 1 diabetes (T1D), but its neuroanatomical correlates and risk factors are unclear. In nondiabetic adults, smaller gray matter volume (GMV) and presence of white matter hyperintensities are associated with psychomotor slowing. We hypothesize that smaller GMV in prefronto-parietal regions explains T1D-related psychomotor slowing. We also inspect the contribution of microvascular disease and hyperglycemia.

METHODS

GMV, white matter hyperintensities (WMH), and glucose levels were measured concurrently with a test of psychomotor speed (Digit Symbol Substitution Test [DSST]) in 95 adults with childhood-onset T1D (mean age/duration = 49/41 years) and 135 similarly aged non-T1D adults. Linear regression models tested associations between DSST and regional GMV, controlling for T1D, sex, and education; a bootstrapping method tested whether regional GMV explained between-group differences in DSST. For the T1D cohort, voxel-based and a priori regions-of-interest methods further tested associations between GMV and DSST, adjusting for WMH, hyperglycemia, and age.

RESULTS

Bilateral putamen, but no other regions examined, significantly attenuated DSST differences between the cohorts (bootstrapped unstandardized indirect effects: -3.49, -3.26; 95% confidence interval = -5.49 to -1.80, -5.29 to -1.44, left and right putamen, respectively). Among T1D, DSST was positively associated with GMV of bilateral putamen and left thalamus. Neither WMH, hyperglycemia, age, nor other factors substantially modified these relationships.

CONCLUSIONS

For middle-aged adults with T1D and cerebral microvascular disease, GMV of basal ganglia may play a critical role in regulating psychomotor speed, as measured via DSST. Studies to quantify the impact of basal ganglia atrophy concurrent with WMH progression on psychomotor slowing are warranted.

Divergent Influences of Cardiovascular Disease Risk Factor Domains on Cognition and Gray and White Matter Morphology

OBJECTIVE

Hypertension, diabetes, dyslipidemia, and obesity are associated with preclinical alterations in cognition and brain structure; however, this often comes from studies of comprehensive risk scores or single isolated factors. We examined associations of empirically derived cardiovascular disease risk factor domains with cognition and brain structure.

METHODS

A total of 124 adults (age, 59.8 [13.1] years; 41% African American; 50% women) underwent neuropsychological and cardiovascular assessments and structural magnetic resonance imaging. Principal component analysis of nine cardiovascular disease risk factors resulted in a four-component solution representing 1, cholesterol; 2, glucose dysregulation; 3, metabolic dysregulation; and 4, blood pressure. Separate linear regression models for learning, memory, executive functioning, and attention/information processing were performed, with all components entered at once, adjusting for age, sex, and education. MRI analyses included whole-brain cortical thickness and tract-based fractional anisotropy adjusted for age and sex.

RESULTS

Higher blood pressure was associated with poorer learning (B = -0.19; p = .019), memory (B = -0.22; p = .005), and executive functioning performance (B = -0.14; p = .031), and lower cortical thickness within the right lateral occipital lobe. Elevated glucose dysregulation was associated with poorer attention/information processing performance (B = -0.21; p = .006) and lower fractional anisotropy in the right inferior and bilateral superior longitudinal fasciculi. Cholesterol was associated with higher cortical thickness within left caudal middle frontal cortex. Metabolic dysfunction was positively associated with right superior parietal lobe, left inferior parietal lobe, and left precuneus cortical thickness.

CONCLUSIONS

Cardiovascular domains were associated with distinct cognitive, gray, and white matter alterations and distinct age groups. Future longitudinal studies may assist in identifying vulnerability profiles that may be most important for individuals with multiple cardiovascular disease risk factors.

Garcinia kola seeds may prevent cognitive and motor dysfunctions in a type 1 diabetes mellitus rat model partly by mitigating neuroinflammation

Background We reported recently that extracts of seeds of Garcinia kola, a plant with established hypoglycemic properties, prevented the loss of inflammation-sensible neuronal populations like Purkinje cells in a rat model of type 1 diabetes mellitus (T1DM). Here, we assessed G. kola extract ability to prevent the early cognitive and motor dysfunctions observed in this model. Methods Rats made diabetic by single injection of streptozotocin were treated daily with either vehicle solution (diabetic control group), insulin, or G. kola extract from the first to the 6th week post-injection. Then, cognitive and motor functions were assessed using holeboard and vertical pole behavioral tests, and animals were sacrificed. Brains were dissected out, cut, and processed for Nissl staining and immunohistochemistry. Results Hyperglycemia (209.26 %), body weight loss (-12.37 %), and T1DM-like cognitive and motor dysfunctions revealed behavioral tests in diabetic control animals were not observed in insulin and extract-treated animals. Similar, expressions of inflammation markers tumor necrosis factor (TNF), iba1 (CD68), and Glial fibrillary acidic protein (GFAP), as well as decreases of neuronal density in regions involved in cognitive and motor functions (-49.56 % motor cortex, -33.24 % medial septal nucleus, -41.8 % /-37.34 % cerebellar Purkinje /granular cell layers) were observed in diabetic controls but not in animals treated with insulin or G. kola. Conclusions Our results indicate that T1DM-like functional alterations are mediated, at least partly, by neuroinflammation and neuronal loss in this model. The prevention of the development of such alterations by early treatment with G. kola confirms the neuroprotective properties of the plant and warrant further mechanistic studies, considering the potential for human disease.

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

Background

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

Methods

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

Results

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

Conclusion

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

Short-term effects of diabetes on neurosteroidogenesis in the rat hippocampus

Diabetes may induce neurophysiological and structural changes in the central nervous system (i.e., diabetic encephalopathy). We here explored whether the levels of neuroactive steroids (i.e., neuroprotective agents) in the hippocampus may be altered by short-term diabetes (i.e., one month). To this aim, by liquid chromatography-tandem mass spectrometry we observed that in the experimental model of the rat raised diabetic by streptozotocin injection, one month of pathology induced changes in the levels of several neuroactive steroids, such as pregnenolone, progesterone and its metabolites (i.e., tetrahydroprogesterone and isopregnanolone) and testosterone and its metabolites (i.e., dihydrotestosterone and 3α-diol). Interestingly these brain changes were not fully reflected by the plasma level changes, suggesting that early phase of diabetes directly affects steroidogenesis and/or steroid metabolism in the hippocampus. These concepts are also supported by the findings that crucial steps of steroidogenic machinery, such as the gene expression of steroidogenic acute regulatory protein (i.e., molecule involved in the translocation of cholesterol into mitochondria) and cytochrome P450 side chain cleavage (i.e., enzyme converting cholesterol into pregnenolone) and 5α-reductase (enzyme converting progesterone and testosterone into their metabolites) are also affected in the hippocampus. In addition, cholesterol homeostasis as well as the functionality of mitochondria, a key organelle in which the limiting step of neuroactive steroid synthesis takes place, are also affected. Data obtained indicate that short-term diabetes alters hippocampal steroidogenic machinery and that these changes are associated with impaired cholesterol homeostasis and mitochondrial dysfunction in the hippocampus, suggesting them as relevant factors for the development of diabetic encephalopathy.

Garcinia kola aqueous suspension prevents cerebellar neurodegeneration in long-term diabetic rat - a type 1 diabetes mellitus model

ETHNOPHARMACOLOGICAL RELEVANCE

The development of compounds able to improve metabolic syndrome and mitigate complications caused by inappropriate glycemic control in type 1 diabetes mellitus is challenging. The medicinal plant with established hypoglycemic properties Garcinia kola Heckel might have the potential to mitigate diabetes mellitus metabolic syndrome and complications.

AIM OF THE STUDY

We have investigated the neuroprotective properties of a suspension of G. kola seeds in long-term type 1 diabetes mellitus rat model.

MATERIALS AND METHODS

Wistar rats, made diabetic by single injection of streptozotocin were monitored for 8 months. Then, they were administered with distilled water or G. kola oral aqueous suspension daily for 30 days. Body weight and glycemia were determined before and after treatment. After sacrifice, cerebella were dissected out and processed for stereological quantification of Purkinje cells. Histopathological and immunohistochemical analyses of markers of neuroinflammation and neurodegeneration were performed.

RESULTS

Purkinje cell counts were significantly increased, and histopathological signs of apoptosis and neuroinflammation decreased, in diabetic animals treated with G. kola compared to diabetic rats given distilled water. Glycemia was also markedly improved and body weight restored to non-diabetic control values, following G. kola treatment.

CONCLUSIONS

These results suggest that G. kola treatment improved the general condition of long-term diabetic rats and protected Purkinje cells partly by improving the systemic glycemia and mitigating neuroinflammation.

Brain Insulin Resistance at the Crossroads of Metabolic and Cognitive Disorders in Humans

Ever since the brain was identified as an insulin-sensitive organ, evidence has rapidly accumulated that insulin action in the brain produces multiple behavioral and metabolic effects, influencing eating behavior, peripheral metabolism, and cognition. Disturbances in brain insulin action can be observed in obesity and type 2 diabetes (T2D), as well as in aging and dementia. Decreases in insulin sensitivity of central nervous pathways, i.e., brain insulin resistance, may therefore constitute a joint pathological feature of metabolic and cognitive dysfunctions. Modern neuroimaging methods have provided new means of probing brain insulin action, revealing the influence of insulin on both global and regional brain function. In this review, we highlight recent findings on brain insulin action in humans and its impact on metabolism and cognition. Furthermore, we elaborate on the most prominent factors associated with brain insulin resistance, i.e., obesity, T2D, genes, maternal metabolism, normal aging, inflammation, and dementia, and on their roles regarding causes and consequences of brain insulin resistance. We also describe the beneficial effects of enhanced brain insulin signaling on human eating behavior and cognition and discuss potential applications in the treatment of metabolic and cognitive disorders.

Disrupting the Adverse Interplay Between Psychiatric and Medical Illnesses

Psychiatric illnesses increase the morbidity and mortality of comorbid medical disease, and current research targets the identification of specific mechanisms that account for this association. Psychotic illness complicates the management of chronic diseases where self-care activities often play a major role, such as in the regulation of blood glucose levels in diabetes. In this issue, Wykes et al. describe an interactive relationship between cognitive functioning and negative symptoms, self-efficacy, and diabetic control in patients with psychotic illnesses and Type 1 diabetes. Although high self-efficacy was associated with better hemoglobin A1C levels in patients with mild negative symptoms and higher cognitive function, in patients with more severe negative symptoms and lower cognitive function, high-self-efficacy was linked to higher A1C levels. These findings point to the need for designing diabetes management plans based on careful assessments of specific psychiatric symptomatology in this population. Severe mental illness is also associated with poor general physical health and higher rates of somatic complaints. Madan and colleagues describe in this issue an integrated model of psychiatric and medical care that substantially reduced physical symptoms in patients with severe mental illness during an 8-week hospitalization, with striking improvements in those presenting with substance abuse and sleep disorders. If these findings are shown to persist after discharge, then accountable care organizations should be encouraged to incorporate this more aggressive approach to caring for this vulnerable population. Such targeted approaches are likely to result in decreased utilization of outpatient medical services and improved long-term outcomes.

Peripheral glucose levels and cognitive outcome after ischemic stroke-Results from the Munich Stroke Cohort

Introduction

The relationship between glucose metabolism and stroke outcome is likely to be complex. We examined whether there is a linear or non-linear relationship between glucose measures in the acute phase of stroke and post-stroke cognition, and whether altered glucose metabolism at different time intervals (long- and short-term before stroke, acute phase) is associated with cognitive outcome.

Patients and methods

In all, 664 consecutively recruited patients with acute ischemic stroke and without pre-stroke dementia were included in this prospective observational study. Blood samples were taken at admission and fasting on the first morning after stroke. Duration of diabetes was assessed by interview. Cognitive outcome was assessed by the Telephone Interview for Cognitive Status 3 months post-stroke. Dose-response analyses were used to investigate non-linearity. Regression analyses were stratified by diabetes status and adjusted for relevant confounders.

Results

Cognitive status was testable in 422 patients (81 with diabetes). There was a non-linear relationship between both admission and fasting glucose levels and cognitive outcome. Lower glucose values were significantly associated with lower Telephone Interview for Cognitive Status scores 3 months post-stroke in patients without diabetes with a similar trend in diabetic patients. There was an inverse association between duration of diabetes and Telephone Interview for Cognitive Status scores (linear regression: -0.10 (95% confidence interval: -0.17 to -0.02) per year increase of diabetes duration), whereas HbA_1c was not related to cognitive outcome. Results were supported by sensitivity analyses accounting for attrition.

Conclusion

Lower glucose levels in the acute phase of stroke are associated with worse cognitive outcome but the relationship is non-linear. Long-term abnormalities in glucose metabolism are also related to poor outcome but this is not the case for shorter term abnormalities. Altered glucose levels at different stages of stroke may affect stroke outcome through different pathways.

Bi-directional interaction between hypoglycaemia and cognitive impairment in elderly patients treated with glucose-lowering agents: a systematic review and meta-analysis

AIMS

To examine the bi-directional relationship, whereby hypoglycaemia is a risk factor for dementia, and where dementia increases risk of hypoglycaemia in older patients with diabetes mellitus treated with glucose-lowering agents.

METHODS

We searched MEDLINE and EMBASE over a 10-year span from 2005 to 2015 (with automated PubMed updates to August 2015) for observational studies of the association between hypoglycaemia and cognitive impairment or dementia in participants aged >55 years. Assessment of study validity was based on ascertainment of hypoglycaemia, dementia and risk of confounding. We conducted random effects inverse variance meta-analyses, and assessed heterogeneity using the I(2) statistic.

RESULTS

We screened 1177 citations, and selected 12 studies, of which nine were suitable for meta-analysis. There were a total of 1,439,818 participants, with a mean age of 75 years. Meta-analysis of five studies showed a significantly increased risk of dementia in patients who had hypoglycaemic episodes: pooled odds ratio 1.68 [95% confidence interval (CI) 1.45, 1.95]. We also found a significantly increased risk of hypoglycaemia in patients with dementia: pooled odds ratio from five studies 1.61 (95% CI 1.25, 2.06). Limitations of the study were heterogeneity in the meta-analysis, and uncertain ascertainment of dementia and hypoglycaemic outcomes and temporal relationships. Publication bias may have favoured the reporting of more significant findings.

CONCLUSIONS

Our meta-analysis shows a bi-directional relationship between cognitive impairment and hypoglycaemia in older patients. Glucose-lowering therapy should be carefully tailored and monitored in older patients who are susceptible to cognitive decline.

Diabetes, Obesity, and the Brain: New Developments in Biobehavioral Medicine

Diabetes and obesity, two major public health concerns, are associated with increased risk for problems in multiple organ systems, including the central nervous system. The adverse effects of diabetes and obesity on cognitive functioning are increasingly well recognized. This special issue of Psychosomatic Medicine features the latest research linking diabetes, obesity, and brain structure, function, and metabolism and follows a special meeting on this topic organized by the American Psychosomatic Society in October 2013. Evidence for the increased prevalence of diabetes and obesity is reviewed as it relates to cognitive decline. These articles indicate that the age of onset of Type 1 diabetes may be relevant to future cognitive function and that disease duration of Type 2 diabetes and sociocultural factors are related to cognitive decline during the aging process. The hypothalamus and other neural circuits, notably the dopaminergic system that underlies feeding and reward-related aspects of food intake, are among the key factors involved in obesity. Research on the associations between obesity and cognitive function is described using the positive effects of weight reduction following bariatric surgery or behavioral methods. This special issue concludes with a conceptual framework for linking obesity and diabetes with accelerated cognitive decline as related to the aging process. The collection of articles highlights the importance of using a life span perspective to understand the influence of both Type 1 and Type 2 diabetes on brain metabolism, function, and structure. Moreover, these studies show that distressing environmental circumstances can adversely influence neurocognitive dysfunction associated with obesity and diabetes.