Glutamic Acid Decarboxylase Levels Research Articles

A 1-year pilot study of intralymphatic injections of GAD-alum in individuals with latent autoimmune diabetes in adults (LADA) with signs of high immunity: No safety concerns and resemblance to juvenile type 1 diabetes.

To test, for the first time in latent autoimmune diabetes in adults (LADA), the effects of autoantigen-specific immunotherapy by intralymphatic administration of aluminium-formulated recombinant human glutamic acid decarboxylase 65 (GAD-alum); specifically, to test if this treatment is safe, to test whether it induces a strong immunological response akin to a similar protocol in type 1 diabetes and to look for associations with preserved beta-cell function. Three GAD-alum injections, 4 μg each, were administered 1 month apart into an inguinal lymph node in 14 people with newly diagnosed LADA (age 30-62 years) presenting with high levels of antibodies against glutamic acid decarboxylase (GADA). Adverse effects, immunological variables and beta-cell function were monitored, with detailed measurements at 5 and 12 months from baseline. Clinical adverse effects were minor and transient and measured laboratory variables were unaffected. All participants completed the study. Treatment raised levels of GADA, elicited strong effects on reactivity of peripheral blood mononuclear cells to GAD and raised cytokine/chemokine levels. Beta-cell function appeared stable preferentially in the seven participants carrying human leukocyte antigen (HLA) haplotypes DR3DQ2, as assessed by C-peptide glucagon tests (P < 0.05 vs. seven non-carriers). Intralymphatic treatment with GAD-alum in LADA is without clinical or other safety concerns over a 12-month period. As in a similar protocol used in type 1 diabetes, treatment exerts a strong immunological impact and is compatible with protection of beta-cell function preferentially in HLA-DR3DQ2 LADA patients. These findings pave the way for a randomized controlled trial in this important subgroup of LADA patients.

Ethanol and caffeine age-dependently alter brain and retinal neurochemical levels without affecting morphology of juvenile and adult zebrafish (Danio rerio).

Adolescent alcohol exposure in humans is predictive of adult development of alcoholism. In rodents, caffeine pre-exposure enhances adult responsiveness to ethanol via a pathway targeted by both compounds. Embryonic exposure to either compound adversely affects development, and both compounds can alter zebrafish behaviors. Here, we evaluate whether co-exposure to caffeine and/or alcohol in adolescence exerts neurochemical changes in retina and brain. Zebrafish (Danio rerio) were given daily 20 min treatments to ethanol (1.5% v/v), caffeine (25-100 mg/L), or caffeine + ethanol for 1 week during mid-late adolescence (53-92 days post fertilization (dpf)) or early adulthood (93-142 dpf). Immediately after exposure, anatomical measurements were taken, including weight, heart rate, pigment density, length, girth, gill width, inner and outer eye distance. Brain and retinal tissue were subsequently collected either (1) immediately, (2) after a short interval (2-4d) following exposure, or (3) after a longer interval that included an acute 1.5% ethanol challenge. Chronic ethanol and/or caffeine exposure did not alter anatomical parameters. However, retinal and brain levels of tyrosine hydroxylase were elevated in fish sacrificed after the long interval following exposure. Protein levels of glutamic acid decarboxylase were also increased, with the highest levels observed in 70-79 dpf fish exposed to caffeine. The influence of ethanol and caffeine exposure on neurochemistry demonstrates specificity of their effects during postembryonic development. Using the zebrafish model to assess neurochemistry relevant to reward and anxiety may inform understanding of the mechanisms that reinforce co-addiction to alcohol and stimulants.

Repeated social defeat stress exacerbates lipopolysaccharide-induced behavioural deficits in mice: ameliorative role of Chrysophyllum albidum fruit extract through anti-neuroinflammation, antioxidant and neurochemical balance.

Development of neuropsychiatric disorder is associated with stress-related increase in pro-inflammatory cytokines. Chrysophyllum albidum fruit is an edible tropical fruit containing vitamins and phenolic compounds, well known for their anti-inflammatory and antioxidant activities. This study was designed to investigate the neuroprotective effect of C. albidum fruit extract (CAFE) on stress and lipopolysaccharide (LPS)-induced behavioral and neurochemical impairments in mice. Male Swiss mice were divided into 6 groups (n = 6). Groups 1-3 were orally treated daily for 14days with normal saline (0.1mL/10g), CAFE (100mg/kg) and Ferulic acid (FA, 10mg/kg), and left in home cage as controls. Groups 4-6 were treated similarly but subjected to repeated social defeat (RSD) stress using the resident-intruder model from days 1-14. The RSD-animals were injected with LPS (125µg/kg, i.p) 60min after each RSD session from days 8-14. Neurobehavioral functions: locomotor, cognitive and anxiety-like behaviors were assessed 24h after the last treatment. Pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α), dopamine, acetylcholinesterase, glutamic acid decarboxylase (GAD), malondialdehyde, nitrites, and reduced glutathione (GSH) were determined in brain tissue. CAFE significantly attenuated RSD and LPS-induced hypolocomotion, cognitive impairment and anxiety-like behavior when compared to the control. Treatment with CAFE also significantly reversed the negative effects of RSD and LPS on pro-inflammatory cytokines, dopamine, acetylcholinesterase, GAD, and oxidative-nitrosative stress levels. The findings clearly indicated that Chrysophyllum albidum fruit demonstrated neuroprotective effects and can play a key role in mitigating against chronic stress and inflammation linked to neuropsychiatric disorders.

Prevalence and factors associated with latent autoimmune diabetes in adults (LADA): a cross-sectional study

BackgroundThe Latent Autoimmune Diabetes in Adults (LADA) is a slowly progressive Type 1 diabetes subgroup with onset during middle age. Studies report that about 10% of adults initially diagnosed with clinical Type 2 diabetes (T2D) have LADA. Inappropriate diagnosis and mismanagement of the LADA can increase the risk of diabetic complications, which affect the quality of life and is the cause of increased mortality. In low-income countries setting, data regarding the magnitude of LADA is limited. We carried out this study to estimate the burden of misdiagnosed LADA among T2D patients in selected health facilities in Dar es Salaam and to bring awareness to the use of Glutamic Acid Decarboxylase (GAD) autoantibody in screening for LADA.MethodologyWe enrolled 186 phenotypically T2D patients in this cross-sectional study, through a standardized data collection tool we obtained participants’ demographic and clinical information. For testing GAD levels, we used a double-antibody Enzyme-Linked Immunosorbent Assay (ELISA). The Fisher’s Exact and student t-tests were used to test the significance of the statistical associations of the glycaemic control and diabetes complications between T2D and LADA.ResultsOut of 186 patients, 156 gave conclusive GAD Ab ELISA reading with LADA accounting for 5.1% (95% CI: 2.5 - 10.0). The mean age of subjects was 54.3 years (Range: 33-85 years). The parameters such as mean age, family history of diabetes mellitus status, Fasting Blood Glucose, clinical characteristics, and complications did not show significant statistical differences between patients with LADA and Type 2 diabetes. However, all LADA- Human Immunodeficiency Virus (HIV) comorbid patients had retinopathy, which was statistically insignificant in 20 (87%) T2D-HIV comorbid patients (p = 0.669). Neither neuropathy, nephropathy, nor Diabetic Mellitus (D.M.) foot syndrome was observed among LADA-HIV comorbid patients. Nevertheless, 22 (95.7%), 3 (13%), and 2 (8.7%) of T2D-HIV comorbidity had neuropathy, nephropathy, or D.M. foot syndrome, respectively.ConclusionsThe study established a LADA prevalence of 5.1% among T2D patients and has shown the role of GAD autoantibody in the screening for LADA. The study calls for a well- designed larger longitudinal study to generate strong evidence on the association of risk factors and complications associated with the LADA. This will develop robust evidence on the association of risk factors and complications associated with the LADA and T2D.

Specific Expression of KCC2 in the α Cells of Normal and Type 1 Diabetes Model Mouse Pancreatic Islets.

Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the mature brain; however, it acts excitatory during development. This difference in action depends on the intracellular chloride ion concentration, primarily regulated by potassium chloride co-transporter2 (KCC2). Sufficient KCC2 expression results in its inhibitory action. GABA is also abundant in pancreatic islets, where it acts differentially on the islet cells, and is involved in carbohydrate metabolism. However, the mechanisms underlying the differential action remain unknown. We performed immunohistochemistry for glutamic acid decarboxylase (GAD), a synthetic enzyme for GABA, and KCC2 in normal adult islets. GAD was co-localized with insulin in β cells, whereas KCC2 was expressed in glucagon-positive α cells. These results are in line with previous observations that GABA decreases glucagon release but increases insulin release, and suggest that GABA and insulin may work together in reducing blood glucose levels under hyperglycemia. Next, we examined the streptozotocin-induced type1 diabetes mellitus mouse model. GAD and insulin expression levels were markedly decreased. KCC2 was expressed in glucagon-positive cells, whereas insulin- and somatostatin-positive cells were KCC2-negative. These findings suggest that in diabetes model, reduced GABA release may cause disinhibition of glucagon release, resulting in increased blood sugar levels and the maintenance of hyperglycemic state.

Time-dependent effects on circulating cytokines in patients with LADA: A decrease in IL1-ra and IL-1 beta is associated with progressive disease

BackgroundCytokines and chemokines participate in autoimmune processes at cellular targets which include insulin-producing beta cells. To which extent such participation is reflected in the circulation has not been conclusively resolved. AimWe compared the time course of cytokines/chemokines in Latent Autoimmune Diabetes in Adults (LADA) patients heterogeneous for high or low autoimmune activity as determined by levels of antibodies against glutamic acid decarboxylase (GADA). MethodsSerum samples to be measured were from a two-armed randomized controlled trial (RCT) in 68 LADA patients. The study encompassed 21 months with C-peptide as primary endpoint. We measured 27 immune mediators at baseline, at 9 and at 21 months (end of study). Results of measurements were analyzed by multiple linear regression. ResultsAt baseline, a high body mass index (BMI) (>26 kg/m2) was associated with elevated levels of the interleukins (IL) IL-1 beta, IL-1ra, IL-2, IL-5, IL-6 and IL-13. Treatment during RCT (sitagliptin vs. insulin) did not affect the time course (21 months) of levels of cytokines/chemokines (by univariate analyses). However, levels of the cytokines IL-1ra and IL-1 beta decreased significantly (p < 0.04 or less) in patients with high vs. low GADA when adjusted for BMI, age, gender (male/female), treatment (insulin/sitagliptin) and study site (Norwegian/Swedish). ConclusionsIn LADA, high levels of GADA, a proxy for high autoimmune activity and linked to a decline in C-peptide, was associated with a decrease of selected cytokines over time. This implies that the decline of IL-1ra and IL-1 beta in the circulation reflects autoimmune activity and beta cell demise in LADA.

The plasma level of glutamic acid decarboxylase 65 (GAD65) increased in severely autistic Iranian children.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder. The major etiological mechanism lies in glutamatergic/GABAergic imbalance. The aim of this study was to evaluate the plasma levels of glutamic acid decarboxylase 65 (GAD65) protein in mildly and severely autistic patients, and also to compare plasma GAD65 concentration in mild and severe autism. In total, 62 autistic patients (aged 6-9 years) and 17 age-matched neurotypically healthy controls were included in the study. The diagnosis, as well as the level of autism, was assessed by applying the Gilliam Autism Rating Scale. Plasma GAD65 protein level was determined using an enzyme-linked immunosorbent assay (ELISA) kit for GAD65. Our findings showed no remarkable alteration in plasma GAD65 concentration in patients with mild autism as compared to healthy subjects, while patients with severe autism showed an increased plasma level of GAD65 as compared to healthy controls and mildly autistic patients. Our findings suggest the level of plasma GAD65 to be considered a potential diagnostic biomarker for the severity of autism (Fig. 2, Ref. 40).

Role of C-Peptide in Relation to Levels of Anti-GAD and Islet Cell Antibodies in Characterizing Types of Diabetes in the Young, in Eastern India

Background: Measuring fasting C-peptide (FCP) and antibodies against Glutamic acid decarboxylase (GADA) and Islet cell antibodies (ICA) are not so commonly explored in children and young adults. Objectives: To assess the levels of FCP, GADA and ICA in subjects below the age of 25 years with DM and compare their levels to differentiate between Autoimmune and Non-Autoimmune Type 1 DM. Methodology: Blood samples of 93 subjects diagnosed with DM, reporting to the tertiary care hospital, were analysed for ICA, GADA and FCP. Receiver operating characteristics (ROC) curves were analysed to check the ability of autoimmune markers, BMI and C-peptide to differentiate between Autoimmune (Ai) and Non-Autoimmune (NonAi) diabetes. Results: 30/93 (32.2%) were positive for anti-GAD ab and/or ICA and categorised as Autoimmune (Ai), the most common antibody being, anti-GAD ab (80%) in them. The level of FCP among Ai compared to NonAi, was significantly low (p 20.75 nmol/l) as a very dependable test for diagnosing Ai, Type 1 DM, in children and young adults. Its sensitivity and specificity are in the range of 86.2% and 96.8% respectively. Low level of C-peptide (<0.36 nmol/l) is a fair indicator for diagnosing Ai diabetes in the same population unlike BMI. Conclusion: This study revealed predominant positivity for anti-GAD ab (80%) among Ai+ patients. ROC analysis shows GADA above 20.75 nmol/l and Fasting C-peptide < 0.36 nmol/l as a good indicator for diagnosing Ai in children and young adults.

Inhibition of the mTORC1/NF-κB Axis Alters Amino Acid Metabolism in Human Hepatocytes

In addition to serving as the building blocks for protein synthesis, amino acids can be used as an energy source, through catabolism. The transamination, oxidative deamination, and decarboxylation processes that occur during amino acid catabolism are catalyzed by specific enzymes, including aspartate aminotransferase (AST), glutamate dehydrogenase (GDH), glutamic acid decarboxylase (GAD), and ornithine decarboxylase (ODC); however, the overall molecular mechanisms through which amino acid catabolism occurs remain largely unknown. To examine the role of mechanistic target of rapamycin complex 1 (mTORC1) on amino acid catabolism, mTORC1 was inactivated by rapamycin or shRNA targeting Raptor, versus activated by overexpressing Rheb or amino acids in human hepatocytes. The expression of amino acid catabolic genes and related transcription factor was investigated by RT/real-time PCR and western blot analysis. A few types of amino acid metabolite were examined by ELISA and HPLC analysis. The data showed that inactivated mTORC1 resulted in inhibition of NF-κB and the expression of AST, GDH, GAD, and ODC, whereas activated mTORC1 enhanced NF-κB activation and the expression levels of the catabolism-associated genes. Further, inhibition of NF-κB reduced the expression levels of AST, GDH, GAD, and ODC. mTORC1 upregulated NF-κB activation and the expression of AST and ODC in response to glutamate and ornithine treatments, whereas rapamycin inhibited the utilization of glutamate and ornithine in hepatocytes. Taken together, these results indicated that the mTORC1/NF-κB axis modulates the rate of amino acid catabolism by regulating the expression of key catabolic enzymes in hepatocytes.

Alpha-asarone Improves Cognitive Function of APP/PS1 Mice and Reducing Aβ42, P-tau and Neuroinflammation, and Promoting Neuron Survival in the Hippocampus

Alzheimer’s disease (AD) is a progressive neurodegenerative disease most often characterized by memory impairment and cognitive decline. Alpha-asarone has been reported to have the potential to treat AD. Our previous studies have found that alpha-asarone improves aged rats’ cognitive function by alleviating neuronal excitotoxicity via type A gamma-aminobutyric acid (GABA) receptors. GABA level’s change, neuroinflammation, and dysfunctional autophagy are found to be associated with AD. However, the effect of alpha-asarone on cognitive function of APP/PS1 transgenic mice and its underlying mechanism in terms of aggregation of amyloid-β42 (Aβ42) and phosphorylated tau (p-tau), glutamic acid decarboxylase (GAD) level, neuroinflammation, and autophagy are unclear. Accordingly, we attempted to explore whether alpha-asarone improves AD mice’s cognitive function and alleviates pathological symptoms by regulating GAD level, inhibiting neuroinflammation, or restore autophagy. We found that alpha-asarone enhanced spatial learning memory and decreased Aβ42 and p-tau levels without influencing the GAD level in APP/PS1 transgenic mice. Also, it decreased the GFAP expression and reduced pro-inflammatory cytokines levels, thus alleviating neuroinflammation. Furthermore, alpha-asarone decreased the excess number of autophagosomes and promoted hippocampal neurons’ survival. In conclusion, the results confirmed the therapeutic effect of alpha-asarone on AD-related astrogliosis, dysfunctional autophagy, and neuronal damage, which indicates its great potential to treat AD.

Repeated maternal separation causes transient reduction in BDNF expression in the medial prefrontal cortex during early brain development, affecting inhibitory neuron development

It is widely accepted that maternal separation (MS) induces stress in children and disrupts neural circuit formation during early brain development. Even though such disruption occurs transiently early in life, its influence persists after maturation, and could lead to various neurodevelopmental disorders. Our recent study revealed that repeated MS reduces the number of inhibitory neurons and synapses in the medial prefrontal cortex (mPFC) and causes mPFC-related social deficits after maturation. However, how MS impedes mPFC development during early brain development remains poorly understood. Here, we focused on brain-derived neurotrophic factor (BDNF) involved in the development of inhibitory neurons, and examined time-dependent BDNF expression in the mPFC during the pre-weaning period in male rats exposed to MS. Our results show that MS attenuates BDNF expression only around the end of the first postnatal week. Likewise, mRNA expression of activity-regulated cytoskeleton-associated protein (Arc), an immediate-early gene whose expression is partly regulated by BDNF, also decreased in the MS group along with the reduction in BDNF expression. On the contrary, mRNA expression of tropomyosin-related kinase B (TrkB), which is a BDNF receptor, was scarcely altered, while its protein expression decreased in the MS group only during the weaning period. In addition, MS reduced mRNA levels of glutamic acid decarboxylase (GAD) 65, a GABA synthesizing enzyme, only during the weaning period. Our results suggest that repeated MS temporarily attenuates BDNF signaling in the mPFC during early brain development. BDNF plays a crucial role in the development of inhibitory neurons; therefore, transient attenuation of BDNF signaling may cause delays in GABAergic neuron development in the mPFC.

Identification of a subgroup of black South Africans with type 1 diabetes who are older at diagnosis but have lower levels of glutamic acid decarboxylase and islet antigen 2 autoantibodies.

To compare the age at diagnosis and prevalence of islet autoantibody [glutamic acid decarboxylase (65kDa) 65 and islet antigen 2] positivity in black and white participants with type 1 diabetes in South Africa, and to analyse the relationship between age at diagnosis and the presence of autoantibodies. Participants were recruited from diabetes outpatient departments and autoantibodies to glutamic acid decarboxylase (65kDa) and islet antigen 2 were measured by enzyme-linked immunosorbent assay. We recruited 472 (353 black and 119 white) participants with type 1 diabetes. Age at diagnosis of diabetes was later in black (19.7±10.5) than in white participants (12.7±10.8years; P<0.001) with a median (interquartile range) disease duration of 5.0 (2.0-10.0) and 8.5 (4.0-20.0) years (P<0.001), respectively. An older age at diagnosis (≥21years) was more frequent in black (152 of 340, 45%) than in white participants (24 of 116, 21%; P<0.001). The prevalence of islet antigen 2 autoantibodies was 19% (66/352) in black and 41% in white participants (48/118; P<0.001). There was no significant difference in glutamic acid decarboxylase (65kDa) autoantibody positivity between black (212/353, 60%) and white participants (77/117, 66%; P=0.269). In black, but not white, participants the prevalence of both glutamic acid decarboxylase (65kDa) and islet antigen 2 autoantibody positivity was significantly lower in participants diagnosed at age≥21years (P<0.001 for both comparisons). The older age at diagnosis, lower prevalence of islet antigen 2 autoantibodies and a distinct subgroup of participants with type 1 diabetes with age at diagnosis of >20years in the black compared to white population suggest a difference in the immunological aetiology of type 1 diabetes in these two population groups.

Sex- and age-related changes in GABA signaling components in the human cortex

Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the nervous system. Previous studies have shown fluctuations in expression levels of GABA signaling components—glutamic acid decarboxylase (GAD), GABA receptor (GABAR) subunit, and GABA transporter (GAT)—with increasing age and between sexes; however, this limited knowledge is highly based on animal models that produce inconsistent findings. This study is the first analysis of the age- and sex-specific changes of the GAD, GABAA/BR subunits, and GAT expression in the human primary sensory and motor cortices; superior (STG), middle (MTG), and inferior temporal gyrus (ITG); and cerebellum. Utilizing Western blotting, we found that the GABAergic system is relatively robust against sex and age-related differences in all brain regions examined. However, we observed several sex-dependent differences in GABAAR subunit expression in STG along with age-dependent GABAAR subunit and GAD level alteration. No significant age-related differences were found in α1, α2, α5, β3, and γ2 subunit expression in the STG. However, we found significantly higher GABAAR α3 subunit expression in the STG in young males compared to old males. We observed a significant sex-dependent difference in α1 subunit expression: males presenting significantly higher levels compared to women across all stages of life in STG. Older females showed significantly lower α2, α5, and β3 subunit expression compared to old males in the STG. These changes found in the STG might significantly influence GABAergic neurotransmission and lead to sex- and age-specific disease susceptibility and progression.

Most Women with Previous Gestational Diabetes Mellitus Have Impaired Glucose Metabolism after a Decade.

Of 1324 women diagnosed with gestational diabetes mellitus (GDM) in Sweden, 25% reported >10 years after the delivery that they had developed diabetes mellitus. We assessed the long-term risk of all glucose metabolic abnormalities in a subgroup of these women. Women (n = 51) previously diagnosed with GDM by capillary blood glucose ≥9.0 mmol/L (≈plasma glucose ≥10.0 mmol/L) after a 2 h 75 g oral glucose tolerance test (OGTT) were included. All underwent a clinical and biochemical evaluation, including a second 2 h 75 g OGTT. Individuals with known type 1 diabetes were excluded. At the follow-up, 12/51 (24%) reported previously diagnosed type 2 diabetes. Another four cases were diagnosed after the second OGTT, increasing the prevalence to 16/51 cases (31%). Impaired fasting plasma glucose (IFG) was diagnosed in 13/51 women and impaired glucose tolerance (IGT) in 10/51 women, leaving only 12 women (24%) with normal glucose tolerance. In addition, 2/51 women had high levels of glutamic acid decarboxylase (GAD) antibodies; of these, one woman classified as type 2 diabetes was reclassified as type 1 diabetes, and the second GAD-positive woman was diagnosed with IGT. Of the women diagnosed with GDM by a 2 h 75 g OGTT, a large proportion had impaired glucose metabolism a decade later, including type 1 and type 2 diabetes.

Correlation Between GAD Antibody Levels and Severity of Gastrointestinal Motility Dysfunction as Determined by Wireless Motility Capsule Testing

Introduction: There is an increasing body of evidence identifying an immune mediated role in the pathogenesis of both paraneoplastic and non-paraneoplastic gastrointestinal dysmotility. One such mechanism is an antibody mediated pathway involving Glutamic Acid Decarboxylase (GAD). Our objective in this study is to determine if the level of circulating GAD antibody correlates with the severity of gastrointestinal dysmotility, or the number of bowel segments impacted as determined by wireless motility capsule(WMC) testing. Methods: The study was conducted as a retrospective cohort analysis. We included all patients seen at The Cleveland Clinic who had a WMC study ordered between 2009 to 2017, and who also had positive Glutamic Acid Decarboxyase (GAD) antibodies. Patients were identified by CPT codes for WMC in the electronic medical record. Patients were excluded from the study if they failed the WMC due to technical failure. A total 304 completed WMT and also had GAD antibody measured. Of these patients, 35 had positive GAD antibodies (>5 IU/mL). Gastric emptying time (GET), Small Bowel Transit time (SBTT), and Large Bowel Transit time (LBTT) were measured using WMC data. The data from the WMC was compared to corresponding GAD antibody levels using pairwise correlation analysis after eliminating outliers. Additionally, the results were transformed to categorical data (abnormal or not) for evaluation of portions of the gastrointestinal tract involved. Abnormal measurements included a GET >4h, SBTT > 6h, or an LBTT >59h. Results: Results were calculated based on GET, SBTT and LBTT independently, as well as SLBTT and WGTT relative to the GAD antibodies. GAD antibody concentrations do not appear to correlate with the degree of gastrointestinal dysmotility as measured by WMC (Table 1). Conclusion: Based on this review of data, it seems that GAD antibody levels cannot be used as a predictor of disease severity, or to predict the location of gastrointestinal dysmotility. However, more research is needed. Empiric treatment with IVIg should not be used in patients with high GAD antibody levels in the absence of additional supportive data. A larger sample size is needed to confirm the findings of this study, and to identify further correlations.441 Figure 1. Correlation of emptying times and GAD levels

Clinical Characteristics of GADA-Positive Patients with Diabetes and the Role of GAD Antibody Assay to Reclassify the Diagnosis in a Limited Resource Setting

Patients with diagnosis of T2DM may also have islet antibodies typically associated with T1DM, as Latent Autoimmune Diabetes of the Adult (LADA). More than 90% of LADA patients in have antibodies against Glutamic Acid Decarboxylase (GADA). Prevalence of LADA is between 4% and 12% of all adults with a clinical T2D phenotype. T1DM in a limited resource setting is generally diagnosed based mainly on clinical features which may lead to misclassified diagnosis. We utilised GAD antibody assay to reassess the challenging referred cases in our speciality centre by biochemical evaluation. We explore the clinical characteristics one-year post diagnosis of T1DM to reclassify the diagnosis in 20 patients (males = 15, females = 5). The complications reported at the time of diagnosis were, peripheral neuropathy (n=3), hypoglycaemia (n=2), peripheral vascular disease (n=1) and amputation of both toes (n=1). Five patients reported positive family history. Mean age (years) 33 ± 8.4, 95% CI 29 - 37, min 18, max 55. Mean levels of HbA1c (%) was 11 ± 3.1, 95% CI 9.6 - 13, min 7.4, max 17. Mean levels of GAD antibody (IU /ml) was 50 ± 84, 95% CI 11 - 90, min 3.6, max 255. Patients were categorised into subgroups by GADA status, GADA low: ≤ 200 IU ml (n=, GADA high: &amp;gt; 200 IU/ml. Three patients reported high GADA levels of which two were males and one female and two reported complications as amputation and hypoglycaemia. Following reclassification, nine patients were re-diagnosed as T2DM with the management plan shifted from primarily insulin based regimen to oral antidiabetics approach. Two patients each were re-diagnosed as Maturity Onset Diabetes of the Young (MODY) and early onset T2DM. Our study highlights the importance of GAD antibody assay for an early precise diagnosis in a limited resource setting. Disclosure P.J. Goswami: None. B.D. Saboo: None. K.K. Patel: None. B.N. Patel: None. N. Wadhwa: None.

Social behavior, neuroimmune markers and glutamic acid decarboxylase levels in a rat model of valproic acid-induced autism

Autism is a complex neurodevelopmental disorder characterized by impaired social communication and social interactions, and repetitive behaviors. The etiology of autism remains unknown and its molecular basis is not yet well understood. Pregnant Sprague-Dawley (SD) rats were administered 600 mg/kg of valproic acid (VPA) by intraperitoneal injection on day 12.5 of gestation. Both 11- to 13-week-old male and female rat models of VPA-induced autism showed impaired sociability and impaired preference for social novelty as compared to the corresponding control SD rats. Significantly reduced mRNA expressions of social behavior-related genes, such as those encoding the serotonin receptor, brain-derived neurotrophic factor and neuroligin3, and significantly increased expression levels of proinflammatory cytokines, such as interleukin-1 β and tumor necrosis factor-α, were noted in the hippocampi of both male and female rats exposed to VPA in utero. The hippocampal expression level of gamma amino butyric acid (GABA) enzyme glutamic acid decarboxylase (GAD) 67 protein was reduced in both male and female VPA-exposed rats as compared to the corresponding control animals. Our results indicate that developmental exposure to VPA affects the social behavior in rats by modulating the expression levels of social behavior-related genes and inflammatory mediators accompanied with changes in GABA enzyme in the hippocampus.

Cerebrospinal Fluid Level of Glutamic Acid Decarboxylase (GAD) Antibody in Patients with Encephalitis

Background: Assaying the Glutamic Acid Decarboxylas( GAD) antibody in patients with encephalitis in cerebrospinal fluid and blood serum and its role in autoimmune encephalitis in children. Objective: This study Aimed at screening for GAD antibody in CSF of children presenting with acute encephalitis with non bacterial cause mostly autoimmune.Participants and methods: study is a pilot prospective study, conducted in the Pediatric department, Children’s Hospital, Ain Shams University.Fifty patients diagnosed with encephalitis exhibited at least one sign of parenchymatous brain dysfunction such as altered consciousness personality or behavior change, seizure, paresis, or ataxia. Encephalitis was defined as the presence of encephalopathy plus at least two of four findings: (1) fever (body temperature>38C); (2) abnormal cerebrospinal fluid examination (pleocytosis>5 white blood cells/mL and/or increased protein content>40 mg/dL) with negative cerebrospinal fluid culture; (3) abnormal electroencephalography findings compatible with encephalitis such as diffuse or focal slow activity, or periodic lateralized epileptiform discharges; and (4)abnormal results of neuroimaging, including computed tomography and magnetic resonance imaging (10), ,with age ranged from 6-144 Months; followed up In the period from September 2014 till March 2016.Basic clinical evaluation and laboratory investigations were done, GAD antibody level was measured in CSF and blood serum. Results: GAD receptor antibody titer was done in CSF which range from (36 -368 ng/l) with median of 64.83 (57.93-74.48), while in serum it range from (42.76-900) ng/l) with median 89.5(58.62-154.5).It was found that 6/50 (12%) patients had high GAD receptor antibody titer were high in CSF. The other 44/50 (88%) patients had low GAD antibody titer. In serum samples of twinty patients we had 8/20 (40%) patients had high GAD antibody titer and the rest were low GAD antibody titer 12/20 (60%).Significant occurrence of DCL, hospitalization plus mechanical ventilation and long term sequel were detected in patients with high GAD antibody titer. EEG findings; Two patients showed generalized epileptogenic activity, one patient had diffuse cortical dysfunction and two patient had multifocal epileptiform discharge and the rest of patients had normal finding. Eighty six precent had normal MRI findings,While 7 patients (14%) had non specific findings;3 patients had transient cortical meningeal enhancment,2 patients had high intensity in medial temporal lobe,one had abnormal signal intensity in medial temporal lobe and one patient had global brain atrophy. Conclusion: GAD Abs are directed against an intracellular antigen. The proposed pathogenic mechanisms of neurological disease in patients with antibodies directed against intracellular proteins is not clear. The present study emphasizes the importance of studying the CSF of patients with encephalitis suspected to be mediated by GAD autoimmunity.Both serum and CSF level must be assessed simultaneously as CSF level may change rapidly with fluctuation of disease. There are great efforts to be done to define the role of these GAD antibodies and to determine how they affect central nervous system function. These studies must be carried out so that appropriate treatments can be provided for the growing number of patients with possible antibody-mediated conditions.

Erratum to: Increased glutamic acid decarboxylase expression in the hypothalamic suprachiasmatic nucleus in depression.

In depression, disrupted circadian rhythms reflect abnormalities in the central circadian pacemaker, the hypothalamic suprachiasmatic nucleus (SCN). Although many SCN neurons are said to be GABAergic, it was not yet known whether and how SCN GABA changes occur in the SCN in depression. We, therefore, studied GABA in the SCN in relation to the changes in arginine vasopressin (AVP), which is one of the major SCN output systems. Postmortem hypothalamus specimens of 13 subjects suffering from depression and of 13 well-matched controls were collected. Quantitative immunocytochemistry was used to analyze the protein levels of glutamic acid decarboxylase (GAD)65/67 and AVP, and quantitative in situ hybridization was used to measure transcript levels of GAD67 in the SCN. There were a significant 58% increase of SCN GAD65/67-ir and a significant 169% increase of SCN GAD67-mRNA in the depression group. In addition, there were a significant 253% increase of AVP-ir in female depression subjects but not in male depression patients. This sex difference was supported by a re-analysis of SCN AVP-ir data of a previous study of our group. Moreover, SCN-AVP-ir showed a significant negative correlation with age in the control group and in the male, but not in the female depression group. Given the crucial role of GABA in mediating SCN function, our finding of increased SCN GABA expression may significantly contribute to the disordered circadian rhythms in depression. The increased SCN AVP-ir in female-but not in male-depression patients-may reflect the higher vulnerability for depression in women.

Increased glutamic acid decarboxylase expression in the hypothalamic suprachiasmatic nucleus in depression

In depression, disrupted circadian rhythms reflect abnormalities in the central circadian pacemaker, the hypothalamic suprachiasmatic nucleus (SCN). Although many SCN neurons are said to be GABAergic, it was not yet known whether and how SCN GABA changes occur in the SCN in depression. We, therefore, studied GABA in the SCN in relation to the changes in arginine vasopressin (AVP), which is one of the major SCN output systems. Postmortem hypothalamus specimens of 13 subjects suffering from depression and of 13 well-matched controls were collected. Quantitative immunocytochemistry was used to analyze the protein levels of glutamic acid decarboxylase (GAD)65/67 and AVP, and quantitative in situ hybridization was used to measure transcript levels of GAD67 in the SCN. There were a significant 58% increase of SCN GAD65/67-ir and a significant 169% increase of SCN GAD67-mRNA in the depression group. In addition, there were a significant 253% increase of AVP-ir in female depression subjects but not in male depression patients. This sex difference was supported by a re-analysis of SCN AVP-ir data of a previous study of our group. Moreover, SCN-AVP-ir showed a significant negative correlation with age in the control group and in the male, but not in the female depression group. Given the crucial role of GABA in mediating SCN function, our finding of increased SCN GABA expression may significantly contribute to the disordered circadian rhythms in depression. The increased SCN AVP-ir in female—but not in male-depression patients—may reflect the higher vulnerability for depression in women.