Stress-Induced Metabolic Disorder in Peripheral CD4+ T Cells Leads to Anxiety-like Behavior.

Physical or mental stress leads to neuroplasticity in the brain and increases the risk of depression and anxiety. Stress exposure causes the dysfunction of peripheral T lymphocytes. However, the pathological role and underlying regulatory mechanism of peripheral T lymphocytes in mood disorders have not been well established. Here, we show that the lack of CD4+ T cells protects mice from stress-induced anxiety-like behavior. Physical stress-induced leukotriene B4 triggers severe mitochondrial fission in CD4+ T cells, which further leads to a variety of behavioral abnormalities including anxiety, depression, and social disorders. Metabolomic profiles and single-cell transcriptome reveal that CD4+ T cell-derived xanthine acts on oligodendrocytes in the left amygdala via adenosine receptor A1. Mitochondrial fission promotes the de novo synthesis of purine via interferon regulatory factor 1 accumulation in CD4+ T cells. Our study implicates a critical link between a purine metabolic disorder in CD4+ T cells and stress-driven anxiety-like behavior.

Phenotypic and molecular spectrum of pyridoxamine-5'-phosphate oxidase deficiency: A scoping review of 87 cases of pyridoxamine-5'-phosphate oxidase deficiency.

Pyridoxamine-5'-phosphate oxidase (PNPO) deficiency is an autosomal recessive pyridoxal 5'-phosphate (PLP)-vitamin-responsive epileptic encephalopathy. The emerging feature of PNPO deficiency is the occurrence of refractory seizures in the first year of life. Pre-maturity and fetal distress, combined with neonatal seizures, are other associated key characteristics. The phenotype results from a dependency of PLP which regulates several enzymes in the body. We present the phenotypic and genotypic spectrum of (PNPO) deficiency based on a literature review (2002-2020) of reports (n = 33) of patients with confirmed PNPO deficiency (n = 87). All patients who received PLP (n = 36) showed a clinical response, with a complete dramatic PLP response with seizure cessation observed in 61% of patients. In spite of effective seizure control with PLP, approximately 56% of patients affected with PLP-dependent epilepsy suffer developmental delay/intellectual disability. There is no diagnostic biomarker, and molecular testing required for diagnosis. However, we noted that cerebrospinal fluid (CSF) PLP was low in 81%, CSF glycine was high in 80% and urinary vanillactic acid was high in 91% of the cases. We observed only a weak correlation between the severity of PNPO protein disruption and disease outcomes, indicating the importance of other factors, including seizure onset and time of therapy initiation. We found that pre-maturity, the delay in initiation of PLP therapy and early onset of seizures correlate with a poor neurocognitive outcome. Given the amenability of PNPO to PLP therapy for seizure control, early diagnosis is essential.

Neuroimaging Spectrum of Inherited Neurotransmitter Disorders.

Inherited neurotransmitter disorders are rare neurometabolic conditions which encompass genetic disorders of neurotransmitter metabolism or transport. The clinical manifestations of these rare disorders are often nonspecific, ranging from encephalopathies and seizures to movement disorders. As a consequence, neurotransmitter disorders are underrecognized and often misdiagnosed. Accurate and timely diagnosis is, however, of utmost importance, given the availability of therapeutic strategies. A high index of clinical suspicion and familiarity with the neuroimaging phenotypes is therefore crucial. While the imaging features of various neurotransmitter disorders often overlap and are nonspecific, imaging can be helpful in providing useful clues to guide the diagnostic algorithm for uncommon conditions in a neonate presenting with nonspecific neurological symptoms. In this review paper, we aim to bring together current knowledge of neuroimaging phenotypes associated with inherited (primary) disorders of neurotransmitter biosynthesis. Magnetic resonance imaging phenotypes of disorders of monoamine biosynthesis, primary cerebral folate deficiency, disorders of pyridoxine metabolism, disorders of gamma-aminobutyric acid metabolism, nonketotic hyperglycinemia (glycine encephalopathy), disorders of serine biosynthesis, and cerebral creatine deficiency syndrome will be discussed and illustrated with case examples.

Encephalopathy in cystic fibrosis.

Cystic fibrosis liver disease (CFLD) affects a large proportion of cystic fibrosis (CF) patients; however encephalopathy is a rare complication. While classical hepatic encephalopathy can be a feature of end-stage liver disease, "hyperammonemic encephalopathy" can be precipitated in previously stable CFLD by various triggers including systemic corticosteroids. We describe one such case and review the relevant literature.

Movement Disorders in Treatable Inborn Errors of Metabolism.

There are several hundred single-gene disorders that we classify as inborn errors of metabolism. Inborn errors of metabolism are often rare and highly heterogeneous multisystem diseases with non-neurological and neurological manifestations, commonly with onset during childhood. Movement disorders are among the most common neurological problems in inborn errors of metabolism, but, in many cases, remain poorly defined. Although movement disorders are usually not the only and often not the presenting symptom, their recognition can facilitate a diagnosis. Movement disorders contribute substantially to the morbidity in inborn errors of metabolism and can have a significant impact on quality of life. Common metabolic movement disorders include the monoamine neurotransmitter disorders, disorders of amino and organic acid metabolism, metal storage disorders, lysosomal storage disorders, congenital disorders of autophagy, disorders of creatine metabolism, vitamin-responsive disorders, and disorders of energy metabolism. Importantly, disease-modifying therapies exist for a number of inborn errors of metabolism, and early recognition and treatment can prevent irreversible CNS damage and reduce morbidity and mortality. A phenomenology-based approach, based on the predominant movement disorder, can facilitate a differential diagnosis and can guide biochemical, molecular, and imaging testing. The complexity of metabolic movement disorders demands an interdisciplinary approach and close collaboration of pediatric neurologists, neurologists, geneticists, and experts in metabolism. In this review, we develop a general framework for a phenomenology-based approach to movement disorders in inborn errors of metabolism and discuss an approach to identifying the "top ten" of treatable inborn errors of metabolism that present with movement disorders-diagnoses that should never be missed. © 2018 International Parkinson and Movement Disorder Society.

Malignant brain tumors in patients with glutaric aciduria type I.

Three young patients with glutaric aciduria type I (age 6-23 years) of different ethnic origins, treated for their metabolic disease since early childhood, presented with malignant central nervous system tumors. We recommend continuing clinical follow-up, including monitoring of neurological manifestations and neuroradiological findings, in all patients with glutaric aciduria type I beyond early childhood, especially if adherence to diet is poor or the treatment was not started neonatally.

Metabolic Encephalopathy: Behind the Name.

Metabolic encephalopathy may be the most common diagnosis in consultative acute neurology. The origin of this term is not generally known but can be traced back. The term replaced more commonly used designations such as organic or functional. The term metabolic encephalopathy was originally linked to organ dysfunction but subsequently became more imprecise. When it expanded to include a large number of diseases, it evolved to "metabolic neuronal dysfunction" and soon could not be distinguished from "quiet delirium" and other designations. This vignette summarizes why the terminology has confused more than clarified but also why it will likely stay in the neurologist's vernacular.

Treatment, Therapy and Management of Metabolic Epilepsy: A Systematic Review.

Metabolic epilepsy is a metabolic abnormality which is associated with an increased risk of epilepsy development in affected individuals. Commonly used antiepileptic drugs are typically ineffective against metabolic epilepsy as they do not address its root cause. Presently, there is no review available which summarizes all the treatment options for metabolic epilepsy. Thus, we systematically reviewed literature which reported on the treatment, therapy and management of metabolic epilepsy from four databases, namely PubMed, Springer, Scopus and ScienceDirect. After applying our inclusion and exclusion criteria as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we reviewed a total of 43 articles. Based on the reviewed articles, we summarized the methods used for the treatment, therapy and management of metabolic epilepsy. These methods were tailored to address the root causes of the metabolic disturbances rather than targeting the epilepsy phenotype alone. Diet modification and dietary supplementation, alone or in combination with antiepileptic drugs, are used in tackling the different types of metabolic epilepsy. Identification, treatment, therapy and management of the underlying metabolic derangements can improve behavior, cognitive function and reduce seizure frequency and/or severity in patients.

Pyridoxine-5'-phosphate oxidase (Pnpo) deficiency: Clinical and biochemical alterations associated with the C.347g>A (P.·Arg116gln) mutation.

BACKGROUND: Pyridoxal-5'-phosphate oxidase (PNPO) deficiency presents as a severe neonatal encephalopathy responsive to pyridoxal-5'-phosphate (PLP) or pyridoxine. Recent studies widened the phenotype of this condition and detected genetic variants on PNPO gene whose pathogenic role and clinical expression remain to be established. OBJECTIVE: This paper aims to characterize the functional effects of the c.347G>A (p.Arg116Gln) mutation in the PNPO gene in order to define its pathogenicity and describe the clinical features of new patients with epilepsy carrying this mutation. METHODS: Arg116Gln protein variant was expressed as recombinant protein. The mutant protein was characterized with respect to structural and kinetic properties, thermal stability, binding constants of cofactor (FMN) and product (PLP). We also reviewed clinical data of 3 new patients carrying the mutation. RESULTS: The Arg116Gln mutation does not alter the overall enzyme structure and only slightly affects its catalytic efficiency; nevertheless, this mutation affects thermal stability of PNPO, reduces its affinity for FMN and impairs transfer of PLP to PLP-dependent enzymes. Three boys with seizure onset between 8months and 3years of age, carrying the Arg116Gln mutation, are described. These three patients exhibited different seizure types associated with interictal EEG abnormalities and slow background activity. Mild/moderate intellectual disability was observed in 2/3 patients. A dramatic therapeutic response to pyridoxine was observed in the only patient who still had active seizures when starting treatment, while in all three patients interictal EEG discharges and background activity improved after pyridoxine treatment was initiated. CONCLUSIONS: The reported data support a pathogenic role of the c.347G>A (p.Arg116Gln) mutation in PNPO deficiency. The later onset of symptoms and the milder epilepsy phenotype of these expand the disease phenotype.

The M405V allele of the glutaryl-CoA dehydrogenase gene is an important marker for glutaric aciduria type I (GA-I) low excretors.

Glutaric aciduria type I (GA-I) is an autosomal recessive organic aciduria resulting from a functional deficiency of glutaryl-CoA dehydrogenase, encoded by GCDH. Two clinically indistinguishable diagnostic subgroups of GA-I are known; low and high excretors (LEs and HEs, respectively). Early medical and dietary interventions can result in significantly better outcomes and improved quality of life for patients with GA-I. We report on nine cases of GA-I LE patients all sharing the M405V allele with two cases missed by newborn screening (NBS) using tandem mass spectrometry (MS/MS). We describe a novel case with the known pathogenic M405V variant and a novel V133L variant, and present updated and previously unreported clinical, biochemical, functional and molecular data on eight other patients all sharing the M405V allele. Three of the nine patients are of African American ancestry, with two as siblings. GCDH activity was assayed in six of the nine patients and varied from 4 to 25% of the control mean. We support the use of urine glutarylcarnitine as a biochemical marker of GA-I by demonstrating that glutarylcarnitine is efficiently cleared by the kidney (50-90%) and that plasma and urine glutarylcarnitine follow a linear relationship. We report the allele frequencies for three known GA-I LE GCDH variants (M405V, V400M and R227P) and note that both the M405V and V400M variants are significantly more common in the population of African ancestry compared to the general population. This report highlights the M405V allele as another important molecular marker in patients with the GA-I LE phenotype. Therefore, the incorporation into newborn screening of molecular screening for the M405V and V400M variants in conjunction with MS/MS could help identify asymptomatic at-risk GA-I LE patients that could potentially be missed by current NBS programs.

Typical and atypical phenotypes of PNPO deficiency with elevated CSF and plasma pyridoxamine on treatment.

Pyridox(am)ine phosphate oxidase (PNPO) deficiency causes severe early infantile epileptic encephalopathy and has been characterized as responding to pyridoxal-5'-phosphate but not to pyridoxine. Two males with PNPO deficiency and novel PNPO mutations are reported and their clinical, metabolic, and video-electroencephalographic (EEG) findings described. The first child showed electro-clinical responses to pyridoxine and deterioration when pyridoxine was withheld. At last review, he has well-controlled epilepsy with pyridoxal-5'-phosphate monotherapy and an autism spectrum disorder. The second child had a perinatal middle cerebral artery infarct and a myoclonic encephalopathy. He failed to respond to pyridoxine but responded well to pyridoxal-5'-phosphate. At the age of 21 months he has global developmental delay and hemiparesis but is seizure-free with pyridoxal-5'-phosphate monotherapy. Plasma and cerebrospinal fluid pyridoxamine levels were increased in both children during treatment with pyridoxine or pyridoxal-5'-phosphate. These observations indicate that differential responses to pyridoxine and pyridoxal-5'-phosphate treatment cannot be relied upon to diagnose PNPO deficiency.

[The use of piribedil for the prevention of falls in elderly patients with metabolic syndrome].

Effects of pirebedil used to prevent falls in elderly patients with metabolic syndrome are discussed. A prospective controlled study showed that therapy with pirebedil significantly decreases the frequency of falls, reduces severity of pro-inflammatory and pro-oxidative activities, improves cognitive abilities. Prevention of falls by virtue of improved cognitive abilities is a new clinical effect of pirebedil and gives reason to recommend it for the treatment of geriatric patients with metabolic syndrome.

Targeting the murine serotonin transporter: insights into human neurobiology.

Mutations resulting in reduced or completely abrogated serotonin-transporter (SERT) function in mice have led to the identification of more than 50 different phenotypic changes, ranging from increased anxiety and stress-related behaviours to gut dysfunction, bone weakness and late-onset obesity with metabolic syndrome. These multiple effects, which can be amplified by gene-environment and gene-gene interactions, are primarily attributable to altered intracellular and extracellular serotonin concentrations during development and adulthood. Much of the human data relating to altered expression of the gene that encodes SERT are based on genetic-association findings or correlations and are therefore not as robust as the experimental mouse results. Nevertheless, SERT-function-modifying gene variants in humans apparently produce many phenotypes that are similar to those that manifest themselves in mice.

Low lysine diet in glutaric aciduria type I--effect on anthropometric and biochemical follow-up parameters.

BACKGROUND: Metabolic treatment in glutaric aciduria type I (GA-I) including a low lysine diet with lysine-free, tryptophan-reduced amino acid supplements (AAS), carnitine supplementation and early start of emergency treatment during putatively threatening episodes of intermittent febrile illness dramatically improves the outcome and thus has been recommended by an international guideline group (Kölker et al, J Inherit Metab Dis 30:5-22, 2007). However, possible affection of linear growth, weight gain and biochemical follow-up monitoring has not been studied systematically. METHODS: Thirty-three patients (n = 29 asymptomatic, n = 4 dystonic) with GA-I who have been identified by newborn screening in Germany from 1999 to 2009 were followed prospectively during the first six years of life. Dietary treatment protocols, anthropometrical and biochemical parameters were longitudinally evaluated. RESULTS: Mean daily intake as percentage of guideline recommendations was excellent for lysine (asymptomatic patients: 101 %; dystonic patients: 103 %), lysine-free, tryptophan-reduced AAS (108 %; 104 %), energy (106 %; 110 %), and carnitine (92 %; 102 %). Low lysine diet did not affect weight gain (mean SDS 0.05) but mildly impaired linear growth in asymptomatic patients (mean SDS -0.38), while dystonic patients showed significantly reduced weight gain (mean SDS -1.32) and a tendency towards linear growth retardation (mean SDS -1.03). Patients treated in accordance with recent recommendations did not show relevant abnormalities of routine biochemical follow-up parameters. INTERPRETATION: Low lysine diet promotes sufficient intake of essential nutrients and anthropometric development in asymptomatic children up to age 6 year, whereas individualized nutritional concepts are required for dystonic patients. Revised recommendations for biochemical monitoring might be required for asymptomatic patients.

[Effect of cytoflavin on some physiological values in patients with toxicohypoxic encephalopathy].

The effect of cytoflavin upon bolus intravenous administration on the state of hemodynamic values and liquid sectors of the organism was studied in patients with toxicohypoxic encephalopathy caused by heavy acute poisoning. It is established that the bolus administration of cytoflavin is less effective than dropwise intravenous injection.

An impairment of cortical GABAergic neurons is involved in alkalosis-induced brain dysfunctions.

Acid-base imbalance leads to pathological cognition and behaviors in the clinical practices. In the comparison with acidosis, the cellular mechanisms underlying alkalosis-induced brain dysfunction remain unclear. By using electrophysiological approach, we investigated the influences of high extracellular pH environment on cortical GABAergic neurons in terms of their responsiveness to synaptic inputs and their ability to produce action potentials. Artificial cerebral spinal fluid in high pH impairs excitatory synaptic transmission and spike initiation in cortical GABAergic neurons. The alkalosis-induced dysfunction of GABAergic neurons is associated with the decrease of receptor responsiveness and the increases of spike refractory periods and threshold potentials. Our studies reveal that alkalosis impairs cortical GABAergic neurons and subsequently deteriorate brain functions. The molecular targets for alkalosis action include glutamate receptor-channels and voltage-gated sodium channels on GABAergic neurons.

Metabolic and toxic myelopathies.

The myelopathies discussed in this article have an underlying metabolic or toxic etiology. They have many clinical, electrophysiologic, and neuropathologic similarities. Preferential involvement of the dorsal columns and/or corticospinal tracts is commonly seen. Variable degrees of peripheral nerve and/or optic nerve involvement may be present. In the presence of clinical or electrophysiologic evidence of peripheral nerve involvement, the term myeloneuropathy is commonly used. The metabolic and toxic myelopathies discussed here are divided into three categories: disorders due to an identified nutrient deficiency such as the subacute combined degeneration of cobalamin/vitamin B12 or copper deficiency, disorders that have a geographical predilection and are due to a suspected toxin such as lathyrism, and disorders due to a possible toxin but without a geographical predilection such as hepatic myelopathy (Table 1).

Glucose metabolism in small subcortical structures in Parkinson's disease.

OBJECTIVES: Evidence from experimental animal models of Parkinson's disease (PD) suggests a characteristic pattern of metabolic perturbation in discrete, very small basal ganglia structures. These structures are generally too small to allow valid investigation by conventional positron emission tomography (PET) cameras. However, the high-resolution research tomograph (HRRT) PET system has a resolution of 2 mm, sufficient for the investigation of important structures such as the pallidum and thalamic subnuclei. MATERIALS AND METHODS: Using the HRRT, we performed [(18)F]-fluorodeoxyglucose (FDG) scans on 21 patients with PD and 11 age-matched controls. We employed three types of normalization: white matter, global mean, and data-driven normalization. We performed volume-of-interest analyses of small subcortical gray matter structures. Voxel-based comparisons were performed to investigate the extent of cortical hypometabolism. RESULTS: The most significant level of relative subcortical hypermetabolism was detected in the external pallidum (GPe), irrespective of normalization strategy. Hypermetabolism was suggested also in the internal pallidum, thalamic subnuclei, and the putamen. Widespread cortical hypometabolism was seen in a pattern very similar to previously reported patterns in patients with PD. CONCLUSION: The presence and extent of subcortical hypermetabolism in PD is dependent on type of normalization. However, the present findings suggest that PD, in addition to widespread cortical hypometabolism, is probably characterized by true hypermetabolism in the GPe. This finding was predicted by the animal 2-deoxyglucose autoradiography literature, in which high-magnitude hypermetabolism was also most robustly detected in the GPe.

Auditory system dysfunction due to infantile thiamine deficiency: long-term auditory sequelae.

Eleven infants who were fed a thiamine-deficient formula for a mean of 3 months were evaluated for immediate and long-term auditory abnormalities. At presentation, 8 infants had auditory neuropathy spectrum disorder (ANSD), which resolved with supplementary thiamine in 5 children, was permanent in 2 children, and deteriorated in 1 patient who died at the age of 7 years. An additional patient had an auditory pattern corresponding to that of auditory neuropathy of brain stem origin. The 2 remaining patients had unilateral cochlear hearing loss. Six to 8 years later, all patients with transient ANSD had normal audiograms, 2 patients had unilateral cochlear hearing loss, and the rest had neural hearing loss. All survivors had a language developmental delay and impaired speech intelligibility of varying degrees, especially in the presence of background noise. Thiamine is crucial for normal auditory development and function, and its deficiency may be considered an acquired metabolic cause of ANSD in infants.