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Hristov M, Nankova A, Andreeva-Gateva P. Alterations of the glutamatergic system in diabetes mellitus. Metab Brain Dis 2024; 39:321-333. [PMID: 37747631 DOI: 10.1007/s11011-023-01299-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/17/2023] [Indexed: 09/26/2023]
Abstract
Diabetes mellitus (DM) is a chronic disease characterized by elevated blood glucose levels caused by a lack of insulin production (type 1 diabetes) or insulin resistance (type 2 diabetes). It is well known that DM is associated with cognitive deficits and metabolic and neurophysiological changes in the brain. Glutamate is the main excitatory neurotransmitter in the central nervous system that plays a key role in synaptic plasticity, learning, and memory processes. An increasing number of studies have suggested that abnormal activity of the glutamatergic system is implicated in the pathophysiology of DM. Dysfunction of glutamatergic neurotransmission in the central nervous system can provide an important neurobiological substrate for many disorders. Magnetic resonance spectroscopy (MRS) is a non-invasive technique that allows a better understanding of the central nervous system factors by measuring in vivo the concentrations of brain metabolites within the area of interest. Here, we briefly review the MRS studies that have examined glutamate levels in the brain of patients with DM. The present article also summarizes the available data on abnormalities in glutamatergic neurotransmission observed in different animal models of DM. In addition, the role of gut microbiota in the development of glutamatergic alterations in DM is addressed. We speculate that therapeutic strategies targeting the glutamatergic system may be beneficial in the treatment of central nervous system-related changes in diabetic patients.
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Affiliation(s)
- Milen Hristov
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, 2 "Zdrave" St, Sofia, 1431, Bulgaria.
| | - Anelia Nankova
- Department of Endocrinology, Faculty of Medicine, Medical University of Sofia, Sofia, 1431, Bulgaria
| | - Pavlina Andreeva-Gateva
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, 2 "Zdrave" St, Sofia, 1431, Bulgaria
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2
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Garcia-Serrano AM, Vieira JPP, Fleischhart V, Duarte JMN. Taurine and N-acetylcysteine treatments prevent memory impairment and metabolite profile alterations in the hippocampus of high-fat diet-fed female mice. Nutr Neurosci 2023; 26:1090-1102. [PMID: 36222315 DOI: 10.1080/1028415x.2022.2131062] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Background: Obesity constitutes a risk factor for cognitive impairment. In rodent models, long-term exposure to obesogenic diets leads to hippocampal taurine accumulation. Since taurine has putative cyto-protective effects, hippocampal taurine accumulation in obese and diabetic models might constitute a counteracting response to metabolic stress. Objective: We tested the hypothesis that treatment with taurine or with N-acetylcysteine (NAC), which provides cysteine for the synthesis of taurine and glutathione, prevent high-fat diet (HFD)-associated hippocampal alterations and memory impairment. Methods: Female mice were fed either a regular diet or HFD. Some mice had access to 3%(w/v) taurine or 3%(w/v) NAC in the drinking water. After 2 months, magnetic resonance spectroscopy (MRS) was used to measure metabolite profiles. Memory was assessed in novel object and novel location recognition tests. Results: HFD feeding caused memory impairment in both tests, and reduced concentration of lactate, phosphocreatine-to-creatine ratio, and the neuronal marker N-acetylaspartate in the hippocampus. Taurine and NAC prevented HFD-induced memory impairment and N-acetylaspartate reduction. NAC, but not taurine, prevented the reduction of lactate and phosphocreatine-to-creatine ratio. MRS revealed NAC/taurine-induced increase of hippocampal glutamate and GABA levels. Conclusion: NAC and taurine can prevent memory impairment, while only NAC prevents alterations of metabolite concentrations in HFD-exposed female mice.
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Affiliation(s)
- Alba M Garcia-Serrano
- Faculty of Medicine, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Joao P P Vieira
- Faculty of Medicine, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Veronika Fleischhart
- Faculty of Medicine, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - João M N Duarte
- Faculty of Medicine, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
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3
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Dolatshahi M, Sanjari Moghaddam H, Saberi P, Mohammadi S, Aarabi MH. Central nervous system microstructural alterations in Type 1 diabetes mellitus: A systematic review of diffusion Tensor imaging studies. Diabetes Res Clin Pract 2023; 205:110645. [PMID: 37004976 DOI: 10.1016/j.diabres.2023.110645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 02/18/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023]
Abstract
AIMS Type 1 diabetes mellitus (T1DM) is a chronic childhood disease with potentially persistent CNS disruptions. In this study, we aimed to systematically review diffusion tensor imaging studies in patients with T1DM to understand the microstructural effects of this entity on individuals' brains METHODS: We performed a systematic search and reviewed the studies to include the DTI studies in individuals with T1DM. The data for the relevant studies were extracted and a qualitative synthesis was performed. RESULTS A total of 19 studies were included, most of which showed reduced FA widespread in optic radiation, corona radiate, and corpus callosum, as well as other frontal, parietal, and temporal regions in the adult population, while most of the studies in the juvenile patients showed non-significant differences or a non-persistent pattern of changes. Also, reduced AD and MD in individuals with T1DM compared to controls and non-significant differences in RD were noted in the majority of studies. Microstructural alterations were associated with clinical profile, including age, hyperglycemia, diabetic ketoacidosis and cognitive performance. CONCLUSION T1DM is associated with microstructural brain alterations including reduced FA, MD, and AD in widespread brain regions, especially in association with glycemic fluctuations and in adult age.
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Affiliation(s)
- Mahsa Dolatshahi
- NeuroImaging Laboratories, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, United States; NeuroImaging Network (NIN), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
| | | | - Parastoo Saberi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Soheil Mohammadi
- NeuroImaging Network (NIN), Universal Scientific Education and Research Network (USERN), Tehran, Iran; School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mohammad Hadi Aarabi
- Department of Neuroscience and Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
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Yauch LM, Ennis-Czerniak K, Frey WH, Tkac I, Rao RB. Intranasal Insulin Attenuates the Long-Term Adverse Effects of Neonatal Hyperglycemia on the Hippocampus in Rats. Dev Neurosci 2022; 44:590-602. [PMID: 36041414 PMCID: PMC9928603 DOI: 10.1159/000526627] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022] Open
Abstract
Hyperglycemia due to relative hypoinsulinism is common in extremely preterm infants and is associated with hippocampus-mediated long-term cognitive impairment. In neonatal rats, hypoinsulinemic hyperglycemia leads to oxidative stress, altered neurochemistry, microgliosis, and abnormal synaptogenesis in the hippocampus. Intranasal insulin (INS) bypasses the blood-brain barrier, targets the brain, and improves synaptogenesis in rodent models, and memory in adult humans with Alzheimer's disease or type 2 diabetes, without altering the blood levels of insulin or glucose. To test whether INS improves hippocampal development in neonatal hyperglycemia, rat pups were subjected to hypoinsulinemic hyperglycemia by injecting streptozotocin (STZ) at a dose of 80 mg/kg i.p. on postnatal day (P) 2 and randomized to INS, 0.3U twice daily from P3-P6 (STZ + INS group), or no treatment (STZ group). The acute effects on hippocampal neurochemical profile and transcript mRNA expression of insulin receptor (Insr), glucose transporters (Glut1, Glut4, and Glut8), and poly(ADP-ribose) polymerase-1 (Parp1, a marker of oxidative stress) were determined on P7 using in vivo 1H MR spectroscopy (MRS) and qPCR. The long-term effects on the neurochemical profile, microgliosis, and synaptogenesis were determined at adulthood using 1H MRS and histochemical analysis. Relative to the control (CONT) group, mean blood glucose concentration was higher from P3 to P6 in the STZ and STZ + INS groups. On P7, MRS showed 10% higher taurine concentration in both STZ groups. qPCR showed 3-folds higher Insr and 5-folds higher Glut8 expression in the two STZ groups. Parp1 expression was 18% higher in the STZ group and normal in the STZ + INS group. At adulthood, blood glucose concentration in the fed state was higher in the STZ and STZ + INS groups. MRS showed 59% higher brain glucose concentration and histochemistry showed microgliosis in the hippocampal subareas in the STZ group. Brain glucose was normal in the STZ + INS group. Compared with the STZ group, phosphocreatine and phosphocreatine/creatine ratio were higher, and microglia in the hippocampal subareas fewer in the STZ + INS group (p < 0.05 for all). Neonatal hyperglycemia was associated with abnormal glucose metabolism and microgliosis in the adult hippocampus. INS administration during hyperglycemia attenuated these adverse effects and improved energy metabolism in the hippocampus.
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Affiliation(s)
- Lauren McClure Yauch
- Division of Endocrinology, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Kathleen Ennis-Czerniak
- Division of Neonatology, Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - William H. Frey
- HealthPartners Center for Memory and Aging, HealthPartners Neurosciences, St. Paul, MN, 55130, USA
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Ivan Tkac
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Raghavendra B. Rao
- Division of Neonatology, Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, MN, 55414, USA
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Sharma S, Brown CE. Microvascular basis of cognitive impairment in type 1 diabetes. Pharmacol Ther 2021; 229:107929. [PMID: 34171341 DOI: 10.1016/j.pharmthera.2021.107929] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/23/2021] [Accepted: 05/19/2021] [Indexed: 02/07/2023]
Abstract
The complex computations of the brain require a constant supply of blood flow to meet its immense metabolic needs. Perturbations in blood supply, even in the smallest vascular networks, can have a profound effect on neuronal function and cognition. Type 1 diabetes is a prevalent and insidious metabolic disorder that progressively and heterogeneously disrupts vascular signalling and function in the brain. As a result, it is associated with an array of adverse vascular changes such as impaired regulation of vascular tone, pathological neovascularization and vasoregression, capillary plugging and blood brain barrier disruption. In this review, we highlight the link between microvascular dysfunction and cognitive impairment that is commonly associated with type 1 diabetes, with the aim of synthesizing current knowledge in this field.
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Affiliation(s)
- Sorabh Sharma
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Craig E Brown
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.
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Chen MX, Cheng S, Lei L, Zhang XF, Liu Q, Lin A, Wallis CU, Lukowicz MJ, Sham PC, Li Q, Ao LJ. The effects of maternal SSRI exposure on the serotonin system, prefrontal protein expression and behavioral development in male and female offspring rats. Neurochem Int 2021; 146:105041. [PMID: 33836218 DOI: 10.1016/j.neuint.2021.105041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 03/21/2021] [Accepted: 03/31/2021] [Indexed: 11/24/2022]
Abstract
Fluoxetine (FLX), a commonly used selective serotonin reuptake inhibitor, is often used to treat depression during pregnancy. However, prenatal exposure to FLX has been associated with a series of neuropsychiatric illnesses. The use of a rodent model can provide a clear indication as to whether prenatal exposure to SSRIs, independent of maternal psychiatric disorders or genetic syndromes, can cause long-term behavioral abnormalities in offspring. Thus, the present study aimed to explore whether prenatal FLX exposure causes long-term neurobehavioral effects, and identify the underlying mechanism between FLX and abnormal behaviors. In our study, 12/mg/kg/day of FLX or equal normal saline (NS) was administered to pregnant Sprague-Dawley (SD) rats (FLX = 30, NS = 27) on gestation day 11 till birth. We assessed the physical development and behavior of offspring, and in vivo magnetic resonance spectroscopy (MRS) was conducted to quantify biochemical alterations in the prefrontal cortex (PFC). Ex vivo measurements of brain serotonin level and a proteomic analysis were also undertaken. Our results showed that the offspring (male offspring in particular) of fluoxetine exposed mothers showed delayed physical development, increased anxiety-like behavior, and impaired social interaction. Moreover, down-regulation of 5-HT and SERT expression were identified in the PFC. We also found that prenatal FLX exposure significantly decreased NAA/tCr with 1H-MRS in the PFC of offspring. Finally, a proteomic study revealed sex-dependent differential protein expression. These findings may have translational importance suggesting that using SSRI medication alone in pregnant mothers may result in developmental delay in their offspring. Our results also help guide the choice of outcome measures in identifying of molecular and developmental mechanisms.
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Affiliation(s)
- Mo Xian Chen
- School of Rehabilitation, Kunming Medical University, Kunming, China
| | - Shu Cheng
- Department of Rehabilitation, China Resources & WISCO General Hospital, Wuhan, China
| | - Lei Lei
- Rehabilitation Medicine Department, The Affiliated Hospital of Southwest Medical University, Tai Ping Road, Luzhou, Sichuan, China
| | - Xiao Fan Zhang
- Department of Psychiatry, Tongji Hospital of Huazhong University of Science and Technology (HUST), China
| | - Qiang Liu
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Aijin Lin
- School of Rehabilitation, Kunming Medical University, Kunming, China
| | | | | | - Pak C Sham
- Department of Psychiatry, The University of Hong Kong, Hong Kong, SAR, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China; Centre for Genomic Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - Qi Li
- Department of Psychiatry, The University of Hong Kong, Hong Kong, SAR, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China.
| | - Li Juan Ao
- School of Rehabilitation, Kunming Medical University, Kunming, China.
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Samoilova J, Matveeva M, Tonkih O, Kudlau D, Oleynik O, Kanev A. A Prospective Study: Highlights of Hippocampal Spectroscopy in Cognitive Impairment in Patients with Type 1 and Type 2 Diabetes. J Pers Med 2021; 11:jpm11020148. [PMID: 33669655 PMCID: PMC7922999 DOI: 10.3390/jpm11020148] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 11/16/2022] Open
Abstract
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.
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Affiliation(s)
- Julia Samoilova
- Medical Faculty, Siberian State Medical University, 634050 Tomsk, Russia; (J.S.); (O.T.); (O.O.); (A.K.)
| | - Mariia Matveeva
- Medical Faculty, Siberian State Medical University, 634050 Tomsk, Russia; (J.S.); (O.T.); (O.O.); (A.K.)
- Correspondence: ; Tel.: +7-913-8152-552
| | - Olga Tonkih
- Medical Faculty, Siberian State Medical University, 634050 Tomsk, Russia; (J.S.); (O.T.); (O.O.); (A.K.)
| | - Dmitry Kudlau
- Institute of Immunology, Federal Medical and Biological Agency of Russia, 115478 Moscow, Russia;
| | - Oxana Oleynik
- Medical Faculty, Siberian State Medical University, 634050 Tomsk, Russia; (J.S.); (O.T.); (O.O.); (A.K.)
| | - Aleksandr Kanev
- Medical Faculty, Siberian State Medical University, 634050 Tomsk, Russia; (J.S.); (O.T.); (O.O.); (A.K.)
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Chen G, Wang Y, Li Y, Zhang L, Dong M. A novel hippocampus metabolite signature in diabetes mellitus rat model of diabetic encephalopathy. Metab Brain Dis 2020; 35:895-904. [PMID: 32367268 DOI: 10.1007/s11011-020-00541-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 01/30/2020] [Indexed: 12/30/2022]
Abstract
Diabetic encephalopathy (DE) is one of the chronic complications of diabetes. Even then, the molecular mechanism underlying DE remains unexplored. In this study, we have made an attempt to investigate the metabolic changes associated with the streptozocin (STZ)-induced cognitive dysfunction in the hippocampus of the rat model, a classical rodent model for DE, with the help of Gas Chromatography-Mass Spectrometry-based method. The STZ injections led to the rise of mean blood glucose levels in the diabetes mellitus (DM) group of rats as compared to the control (CON) group of rats throughout the experiment. However, we did not find any significant difference between the blood glucose levels of the DM & the CON groups of rats before the STZ injection. The results indicated a behavioral and morphological cognitive dysfunction in the DM groups of rats. The metabolomic investigation of these DE rats demonstrated a lower level of N-acetylaspartate and dihydroxyacetone phosphate accompanied by a higher level of homocysteine and glutamate as against the CON group of rats. The outcome of this study may unravel the underlying pathophysiological mechanism of DE. Also, the metabolomic data from this study may provide a platform for the development of DE biomarkers.
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Affiliation(s)
- Guanghui Chen
- Department of Pharmacy, Renmin Hospital of Wuhan University, Wuhan, 430071, China
| | - Yizhong Wang
- Xiangyang No.1 People' Hospital, Hubei University of Medicine, Xiangyang, 441000, China
| | - Yang Li
- Department of Pharmacy, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430071, China
| | - Lujun Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, 430071, No.99, Zhang zhi dong Road, Wuchang District, Wuhan, Hubei Province, China
| | - Meixue Dong
- Department of Neurology, Renmin Hospital of Wuhan University, 430071, No.99, Zhang zhi dong Road, Wuchang District, Wuhan, Hubei Province, China.
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Chandrasekaran K, Choi J, Arvas MI, Salimian M, Singh S, Xu S, Gullapalli RP, Kristian T, Russell JW. Nicotinamide Mononucleotide Administration Prevents Experimental Diabetes-Induced Cognitive Impairment and Loss of Hippocampal Neurons. Int J Mol Sci 2020; 21:ijms21113756. [PMID: 32466541 PMCID: PMC7313029 DOI: 10.3390/ijms21113756] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 12/12/2022] Open
Abstract
Diabetes predisposes to cognitive decline leading to dementia and is associated with decreased brain NAD+ levels. This has triggered an intense interest in boosting nicotinamide adenine dinucleotide (NAD+) levels to prevent dementia. We tested if the administration of the precursor of NAD+, nicotinamide mononucleotide (NMN), can prevent diabetes-induced memory deficits. Diabetes was induced in Sprague-Dawley rats by the administration of streptozotocin (STZ). After 3 months of diabetes, hippocampal NAD+ levels were decreased (p = 0.011). In vivo localized high-resolution proton magnetic resonance spectroscopy (MRS) of the hippocampus showed an increase in the levels of glucose (p < 0.001), glutamate (p < 0.001), gamma aminobutyric acid (p = 0.018), myo-inositol (p = 0.018), and taurine (p < 0.001) and decreased levels of N-acetyl aspartate (p = 0.002) and glutathione (p < 0.001). There was a significant decrease in hippocampal CA1 neuronal volume (p < 0.001) and neuronal number (p < 0.001) in the Diabetic rats. Diabetic rats showed hippocampal related memory deficits. Intraperitoneal NMN (100 mg/kg) was given after induction and confirmation of diabetes and was provided on alternate days for 3 months. NMN increased brain NAD+ levels, normalized the levels of glutamate, taurine, N-acetyl aspartate (NAA), and glutathione. NMN-treatment prevented the loss of CA1 neurons and rescued the memory deficits despite having no significant effect on hyperglycemic or lipidemic control. In hippocampal protein extracts from Diabetic rats, SIRT1 and PGC-1α protein levels were decreased, and acetylation of proteins increased. NMN treatment prevented the diabetes-induced decrease in both SIRT1 and PGC-1α and promoted deacetylation of proteins. Our results indicate that NMN increased brain NAD+, activated the SIRT1 pathway, preserved mitochondrial oxidative phosphorylation (OXPHOS) function, prevented neuronal loss, and preserved cognition in Diabetic rats.
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Affiliation(s)
- Krish Chandrasekaran
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (J.C.); (M.I.A.); (M.S.); (S.S.)
| | - Joungil Choi
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (J.C.); (M.I.A.); (M.S.); (S.S.)
- Veterans Affairs Medical Center, Baltimore, MD 21201, USA;
| | - Muhammed Ikbal Arvas
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (J.C.); (M.I.A.); (M.S.); (S.S.)
| | - Mohammad Salimian
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (J.C.); (M.I.A.); (M.S.); (S.S.)
| | - Sujal Singh
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (J.C.); (M.I.A.); (M.S.); (S.S.)
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (S.X.); (R.P.G.)
| | - Rao P Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (S.X.); (R.P.G.)
| | - Tibor Kristian
- Veterans Affairs Medical Center, Baltimore, MD 21201, USA;
- Department of Anesthesiology; University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - James William Russell
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (J.C.); (M.I.A.); (M.S.); (S.S.)
- Veterans Affairs Medical Center, Baltimore, MD 21201, USA;
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Correspondence:
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10
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Mitochondria and the Brain: Bioenergetics and Beyond. Neurotox Res 2019; 36:219-238. [DOI: 10.1007/s12640-019-00061-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 05/06/2019] [Indexed: 12/20/2022]
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11
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Wiegers EC, Rooijackers HM, van Asten JJA, Tack CJ, Heerschap A, de Galan BE, van der Graaf M. Elevated brain glutamate levels in type 1 diabetes: correlations with glycaemic control and age of disease onset but not with hypoglycaemia awareness status. Diabetologia 2019; 62:1065-1073. [PMID: 31001674 PMCID: PMC6509078 DOI: 10.1007/s00125-019-4862-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/04/2019] [Indexed: 12/27/2022]
Abstract
AIMS/HYPOTHESIS Chronic hyperglycaemia in type 1 diabetes affects the structure and functioning of the brain, but the impact of recurrent hypoglycaemia is unclear. Changes in the neurochemical profile have been linked to loss of neuronal function. We therefore aimed to investigate the impact of type 1 diabetes and burden of hypoglycaemia on brain metabolite levels, in which we assumed the burden to be high in individuals with impaired awareness of hypoglycaemia (IAH) and low in those with normal awareness of hypoglycaemia (NAH). METHODS We investigated 13 non-diabetic control participants, 18 individuals with type 1 diabetes and NAH and 13 individuals with type 1 diabetes and IAH. Brain metabolite levels were determined by analysing previously obtained 1H magnetic resonance spectroscopy data, measured under hyperinsulinaemic-euglycaemic conditions. RESULTS Brain glutamate levels were higher in participants with diabetes, both with NAH (+15%, p = 0.013) and with IAH (+19%, p = 0.003), compared with control participants. Cerebral glutamate levels correlated with HbA1c levels (r = 0.40; p = 0.03) and correlated inversely (r = -0.36; p = 0.04) with the age at diagnosis of diabetes. Other metabolite levels did not differ between groups, apart from an increase in aspartate in IAH. CONCLUSIONS/INTERPRETATION In conclusion, brain glutamate levels are elevated in people with type 1 diabetes and correlate with glycaemic control and age of disease diagnosis, but not with burden of hypoglycaemia as reflected by IAH. This suggests a potential role for glutamate as an early marker of hyperglycaemia-induced cerebral complications of type 1 diabetes. ClinicalTrials.gov NCT03286816; NCT02146404; NCT02308293.
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Affiliation(s)
- Evita C Wiegers
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands.
| | - Hanne M Rooijackers
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Jack J A van Asten
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine, Radboud university medical center, Nijmegen, the Netherlands
| | - Marinette van der Graaf
- Department of Radiology and Nuclear Medicine (766), Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
- Department of Pediatrics, Radboud university medical center, Nijmegen, the Netherlands
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12
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Zhang H, Zou Y, Lei H. Regional metabolic differences in rat prefrontal cortex measured with in vivo 1 H-MRS correlate with regional histochemical differences. NMR IN BIOMEDICINE 2019; 32:e4024. [PMID: 30376204 DOI: 10.1002/nbm.4024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 06/08/2023]
Abstract
Many neurological/psychiatric disorders are associated with metabolic abnormalities in the brain observable with in vivo proton MRS (1 H-MRS). The underlying molecular/cellular mechanisms and functional correlations of such metabolic alterations, however, are yet to be understood fully. The rodent prefrontal cortex (PFC) is comprised of multiple sub-regions with distinctive cytoarchitecture and functions, providing a good model system to study the correlations among cerebral metabolism, regional cytoarchitecture and connectivity. In this study, the metabolic profiles in two voxels containing mainly the medial PFC (mPFC) and posterior part of the cingulate cortex (pCG), respectively, were measured with single-voxel in vivo 1 H-MRS in adult male rats. The levels of glutamine synthetase and glutamatergic synaptic proteins, including vesicular glutamate transporter 1, vesicular glutamate transporter 2 (VGLUT2) and post-synaptic density protein 95 (PSD95), as well as the density of astrocytes, in these two regions were also compared semi-quantitatively. It was shown that, relative to the pCG voxel, the mPFC voxel had significantly higher N-acetyl aspartate, glutamate (Glu), glutamine (Gln), Glx (Glu + Gln), myo-inositol and taurine levels. The VGLUT2/PSD95 levels and astrocyte density were also higher in the mPFC voxel than in the pCG voxel. Taken together, these results indicated that regional metabolic variations in the PFC of the adult male rat may reflect regional differences in the density of astrocytes and glutamatergic terminals associated with subcortical projections. The study provided a link between the Glu concentration measured with localized in vivo 1 H-MRS and regional glutamatergic activities/connections in the rat PFC.
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Affiliation(s)
- Hui Zhang
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yijuan Zou
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Hao Lei
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
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13
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Metabolic Changes Associated with a Rat Model of Diabetic Depression Detected by Ex Vivo 1H Nuclear Magnetic Resonance Spectroscopy in the Prefrontal Cortex, Hippocampus, and Hypothalamus. Neural Plast 2018; 2018:6473728. [PMID: 29849562 PMCID: PMC5911311 DOI: 10.1155/2018/6473728] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 02/12/2018] [Accepted: 03/11/2018] [Indexed: 01/08/2023] Open
Abstract
Diabetic patients often present with comorbid depression. However, the pathogenetic mechanisms underlying diabetic depression (DD) remain unclear. To explore the mechanisms underpinning the pathogenesis of the disease, we used ex vivo 1H nuclear magnetic resonance spectroscopy and immunohistochemistry to investigate the main metabolic and pathological changes in various rat brain areas in an animal model of DD. Compared with the control group, rats in the DD group showed significant decreases in neurotransmitter concentrations of glutamate (Glu) and glutamine (Gln) in the prefrontal cortex (PFC), hippocampus, and hypothalamus and aspartate and glycine in the PFC and hypothalamus. Gamma-aminobutyric acid (GABA) was decreased only in the hypothalamus. Levels of the energy product, lactate, were higher in the PFC, hippocampus, and hypothalamus of rats with DD than those in control rats, while creatine was lower in the PFC and hippocampus, and alanine was lower in the hypothalamus. The levels of other brain metabolites were altered, including N-acetyl aspartate, taurine, and choline. Immunohistochemistry analysis revealed that expressions of both glutamine synthetase and glutaminase were decreased in the PFC, hippocampus, and hypothalamus of rats with DD. The metabolic changes in levels of Glu, Gln, and GABA indicate an imbalance of the Glu-Gln metabolic cycle between astrocytes and neurons. Our results suggest that the development of DD in rats may be linked to brain metabolic changes, including inhibition of the Glu-Gln cycle, increases in anaerobic glycolysis, and disturbances in the lactate-alanine shuttle, and associated with dysfunction of neurons and astrocytes.
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14
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Coucha M, Abdelsaid M, Ward R, Abdul Y, Ergul A. Impact of Metabolic Diseases on Cerebral Circulation: Structural and Functional Consequences. Compr Physiol 2018; 8:773-799. [PMID: 29687902 DOI: 10.1002/cphy.c170019] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Metabolic diseases including obesity, insulin resistance, and diabetes have profound effects on cerebral circulation. These diseases not only affect the architecture of cerebral blood arteries causing adverse remodeling, pathological neovascularization, and vasoregression but also alter the physiology of blood vessels resulting in compromised myogenic reactivity, neurovascular uncoupling, and endothelial dysfunction. Coupled with the disruption of blood brain barrier (BBB) integrity, changes in blood flow and microbleeds into the brain rapidly occur. This overview is organized into sections describing cerebrovascular architecture, physiology, and BBB in these diseases. In each section, we review these properties starting with larger arteries moving into smaller vessels. Where information is available, we review in the order of obesity, insulin resistance, and diabetes. We also tried to include information on biological variables such as the sex of the animal models noted since most of the information summarized was obtained using male animals. © 2018 American Physiological Society. Compr Physiol 8:773-799, 2018.
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Affiliation(s)
- Maha Coucha
- South University, School of Pharmacy, Savannah, Georgia, USA
| | | | - Rebecca Ward
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Yasir Abdul
- Charlie Norwood VA Medical Center, Augusta, Georgia, USA.,Department of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Adviye Ergul
- Charlie Norwood VA Medical Center, Augusta, Georgia, USA.,Department of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
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15
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Ribeiro M, Castelhano J, Petrella LI, Sereno J, Rodrigues T, Neves C, Letra L, Baptista FI, Seiça R, Matafome P, Castelo-Branco M. High-fat diet induces a neurometabolic state characterized by changes in glutamate and N-acetylaspartate pools associated with early glucose intolerance: An in vivo multimodal MRI study. J Magn Reson Imaging 2018; 48:757-766. [PMID: 29377412 DOI: 10.1002/jmri.25942] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/18/2017] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Type-2 diabetes mellitus (T2DM) is a metabolic disorder with a broad range of complications in the brain that depend on the conditions that precede its onset, such as obesity and metabolic syndromes. It has been suggested that neurotransmitter and metabolic perturbations may emerge even before the early stages of T2DM and that high-caloric intake could adversely influence the brain in such states. Notwithstanding, evidence for neurochemical and structural alterations in these conditions are still sparse and controversial. PURPOSE To evaluate the influence of high-fat diet in the neurochemical profile and structural integrity of the rodent brain. STUDY TYPE Prospective. SUBJECTS Wistar rats (n = 12/group). FIELD STRENGTH/SEQUENCE A PRESS, ISIS, RARE, and EPI sequences were performed at 9.4T. ASSESSMENT Neurochemical and structural parameters were assessed by magnetic resonance spectroscopy, voxel-based morphometry, volumetry, and diffusion tensor imaging. STATISTICAL TESTS Measurements were compared through Student and Mann-Whitney tests. Pearson correlation was used to assess relationships between parameters. RESULTS Animals submitted to high-caloric intake gained weight (P = 0.003) and developed glucose intolerance (P < 0.001) but not hyperglycemia. In the hippocampus, the diet induced perturbations in glutamatergic metabolites reflected by increased levels of glutamine (P = 0.016) and glutamatergic pool (Glx) (P = 0.036), which were negatively correlated with glucose intolerance (glutamine, r = -0.804, P = 0.029), suggesting a link with neurometabolic dysregulation. At caudate-putamen, high-fat diet led to a surprising increase in the pool of N-acetylaspartate (P = 0.028). A relation with metabolic changes was again suggested by the negative correlation between glucose intolerance and levels of glutamatergic metabolites in this region (glutamate, r = -0.845, P = 0.014; Glx, r = -0.834, P = 0.020). Neither changes in phosphate compounds nor major structural alterations were observed for both regions. DATA CONCLUSION We found evidence that high-fat diet-induced obesity leads to distinct early and region-specific metabolic/neurochemical imbalances in the presence of early glucose intolerance even when structural alterations or T2DM are absent. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018.
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Affiliation(s)
- Mário Ribeiro
- Center for Neuroscience and Cell Biology - Institute of Biomedical Imaging and Life Science (CNC.IBILI), University of Coimbra, Coimbra, Portugal
- CiBIT, Institute of Nuclear Science Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal
| | - João Castelhano
- Center for Neuroscience and Cell Biology - Institute of Biomedical Imaging and Life Science (CNC.IBILI), University of Coimbra, Coimbra, Portugal
- CiBIT, Institute of Nuclear Science Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal
| | - Lorena I Petrella
- Center for Neuroscience and Cell Biology - Institute of Biomedical Imaging and Life Science (CNC.IBILI), University of Coimbra, Coimbra, Portugal
- CiBIT, Institute of Nuclear Science Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal
| | - José Sereno
- Center for Neuroscience and Cell Biology - Institute of Biomedical Imaging and Life Science (CNC.IBILI), University of Coimbra, Coimbra, Portugal
- CiBIT, Institute of Nuclear Science Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal
| | - Tiago Rodrigues
- Laboratory of Physiology, Institute of Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal
| | - Christian Neves
- Laboratory of Physiology, Institute of Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal
| | - Liliana Letra
- Laboratory of Physiology, Institute of Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal
| | - Filipa I Baptista
- Center for Neuroscience and Cell Biology - Institute of Biomedical Imaging and Life Science (CNC.IBILI), University of Coimbra, Coimbra, Portugal
- Laboratory of Physiology, Institute of Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal
| | - Raquel Seiça
- Laboratory of Physiology, Institute of Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal
| | - Paulo Matafome
- Laboratory of Physiology, Institute of Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal
- Coimbra Health School (ESTeSC), Department of Complementary Sciences, University of Coimbra, Coimbra, Portugal
| | - Miguel Castelo-Branco
- Center for Neuroscience and Cell Biology - Institute of Biomedical Imaging and Life Science (CNC.IBILI), University of Coimbra, Coimbra, Portugal
- CiBIT, Institute of Nuclear Science Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal
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16
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Li S, Wang X, Yang J, Lei H, Wang X, Xiang Y. Metabolic profile of visual cortex in diabetic rats measured with in vivo proton MRS. NMR IN BIOMEDICINE 2017; 30:e3783. [PMID: 28915340 DOI: 10.1002/nbm.3783] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 07/09/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
The purpose of the present study was to characterize the metabolic profile of the visual cortex in streptozotocin-induced Type 1 diabetic rats by means of in vivo proton MRS. Several metabolite concentration ratios in the visual cortex were calculated. In addition, postmortem histologic analyses for retinal ganglion cell (RGC) loss, optic nerve injury and visual cortex alterations were monitored. The results showed that diabetes induced several changes in visual cortex metabolites, such as reduced N-acetylaspartate, glutamate, γ-aminobutyric acid, taurine and choline-containing compound levels. Nevertheless, myo-inositol levels increased significantly as compared with controls. Remarkable RGC loss and optic nerve degeneration were observed by morphological analysis. Moreover, the results showed significant neuronal loss and glial activation in the visual cortex. These findings indicated that, besides vascular abnormalities, neuronal loss and degeneration in the visual pathway were induced due to disrupted glucose homeostasis in diabetes. Metabolic or functional abnormalities were induced in cerebral neurons of the visual cortex by diabetes.
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Affiliation(s)
- Shuang Li
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China
| | - Xinghua Wang
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Junjie Yang
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hao Lei
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Xuxia Wang
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Yi Xiang
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China
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17
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Taurine counteracts the neurotoxic effects of streptozotocin-induced diabetes in rats. Amino Acids 2017; 50:95-104. [DOI: 10.1007/s00726-017-2495-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 09/18/2017] [Indexed: 01/07/2023]
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18
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Hardigan T, Hernandez C, Ward R, Hoda MN, Ergul A. TLR2 knockout protects against diabetes-mediated changes in cerebral perfusion and cognitive deficits. Am J Physiol Regul Integr Comp Physiol 2017; 312:R927-R937. [PMID: 28336553 DOI: 10.1152/ajpregu.00482.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/25/2017] [Accepted: 02/17/2017] [Indexed: 12/29/2022]
Abstract
The risk of cognitive decline in diabetes (Type 1 and Type 2) is significantly greater compared with normoglycemic patients, and the risk of developing dementia in diabetic patients is doubled. The etiology for this is likely multifactorial, but one mechanism that has gained increasing attention is decreased cerebral perfusion as a result of cerebrovascular dysfunction. The innate immune system has been shown to play a role in diabetic vascular complications, notably through the Toll-like receptor (TLR)-stimulated release of proinflammatory cytokines and chemokines that lead to vascular damage. TLR2 has been implicated in playing a crucial role in the development of diabetic microvascular complications, such as nephropathy, and thus, we hypothesized that TLR2-mediated cerebrovascular dysfunction leads to decreased cerebral blood flow (CBF) and cognitive impairment in diabetes. Knockout of TLR2 conferred protection from impaired CBF in early-stage diabetes and from hyperperfusion in long-term diabetes, prevented the development of endothelium-dependent vascular dysfunction in diabetes, created a hyperactive and anxiolytic phenotype, and protected against diabetes-induced impairment of long-term hippocampal and prefrontal cortex-mediated fear learning. In conclusion, these findings support the involvement of TLR2 in the pathogenesis of diabetic vascular disease and cognitive impairment.
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Affiliation(s)
- Trevor Hardigan
- Department of Physiology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Caterina Hernandez
- Department of Pharmacology and Toxicology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia.,Department of Small Animal Behavior Core Facility, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Rebecca Ward
- Department of Neuroscience, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - M Nasrul Hoda
- Department of Medical Laboratory, Imaging and Radiologic Sciences, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia.,Department of Neurology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia.,Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia; and
| | - Adviye Ergul
- Department of Physiology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia; .,Charlie Norwood Veterans Administration Medical Center, Augusta, Georgia
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