Thiamine deficiency contributes to synapse and neural circuit defects.

BACKGROUND: The previous studies have demonstrated the reduction of thiamine diphosphate is specific to Alzheimer's disease (AD) and causal factor of brain glucose hypometabolism, which is considered as a neurodegenerative index of AD and closely correlates with the degree of cognitive impairment. The reduction of thiamine diphosphate may contribute to the dysfunction of synapses and neural circuits, finally leading to cognitive decline. RESULTS: To demonstrate this hypothesis, we established abnormalities in the glucose metabolism utilizing thiamine deficiency in vitro and in vivo, and we found dramatically reduced dendrite spine density. We further detected lowered excitatory neurotransmission and impaired hippocampal long-term potentiation, which are induced by TPK RNAi in vitro. Importantly, via treatment with benfotiamine, Aß induced spines density decrease was considerably ameliorated. CONCLUSIONS: These results revealed that thiamine deficiency contributed to synaptic dysfunction which strongly related to AD pathogenesis. Our results provide new insights into pathogenesis of synaptic and neuronal dysfunction in AD.

Thiamine diphosphate reduction strongly correlates with brain glucose hypometabolism in Alzheimer's disease, whereas amyloid deposition does not.

BACKGROUND: The underlying mechanism of brain glucose hypometabolism, an invariant neurodegenerative feature that tightly correlates with cognitive impairment and disease progression of Alzheimer's disease (AD), remains elusive. METHODS: Positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) was used to evaluate brain glucose metabolism, presented as the rate of 2-[18F]fluoro-2-deoxy-D-glucose standardized uptake value ratio (FDG SUVR) in patients with AD or control subjects and in mice with or without thiamine deficiency induced by a thiamine-deprived diet. Brain amyloid-ß (Aß) deposition in patients with clinically diagnosed AD was quantified by performing assays using 11C-Pittsburgh compound B PET. The levels of thiamine metabolites in blood samples of patients with AD and control subjects, as well as in blood and brain samples of mice, were detected by high-performance liquid chromatography with fluorescence detection. RESULTS: FDG SUVRs in frontal, temporal, and parietal cortices of patients with AD were closely correlated with the levels of blood thiamine diphosphate (TDP) and cognitive abilities, but not with brain Aß deposition. Mice on a thiamine-deprived diet manifested a significant decline of FDG SUVRs in multiple brain regions as compared with those in control mice, with magnitudes highly correlating with both brain and blood TDP levels. There were no significant differences in the changes of FDG SUVRs in observed brain regions between amyloid precursor protein/presenilin-1 and wild-type mice following thiamine deficiency. CONCLUSIONS: We demonstrate, for the first time to our knowledge, in vivo that TDP reduction strongly correlates with brain glucose hypometabolism, whereas amyloid deposition does not. Our study provides new insight into the pathogenesis and therapeutic strategy for AD.

Thiamine deficiency contributes to synapse and neural circuit defects

BACKGROUND: The previous studies have demonstrated the reduction of thiamine diphosphate is specific to Alzheimer's disease (AD) and causal factor of brain glucose hypometabolism, which is considered as a neurodegenerative index of AD and closely correlates with the degree of cognitive impairment. The reduction of thiamine diphosphate may contribute to the dysfunction of synapses and neural circuits, finally leading to cognitive decline. RESULTS: To demonstrate this hypothesis, we established abnormalities in the glucose metabolism utilizing thiamine deficiency in vitro and in vivo, and we found dramatically reduced dendrite spine density. We further detected lowered excitatory neurotransmission and impaired hippocampal long-term potentiation, which are induced by TPK RNAi in vitro. Importantly, via treatment with benfotiamine, Aß induced spines density decrease was considerably ameliorated. CONCLUSIONS: These results revealed that thiamine deficiency contributed to synaptic dysfunction which strongly related to AD pathogenesis. Our results provide new insights into pathogenesis of synaptic and neuronal dysfunction in AD.

Transketolase: observations in alcohol-related brain damage research.

Thiamin, or vitamin B1, is crucial for brain function. In its active form, thiamin pyrophosphate (TPP), it is a co-enzyme for several enzymes, including transketolase. Transketolase is an important enzyme in the non-oxidative branch of the pentose phosphate pathway (PPP), a pathway responsible for generating reducing equivalents, which is essential for energy transduction and for generating ribose for nucleic acid synthesis. Transketolase also links the PPP to glycolysis, allowing a cell to adapt to a variety of energy needs, depending on its environment. Abnormal transketolase expression and/or activity have been implicated in a number of diseases where thiamin availability is low, including Wernicke-Korsakoff's Syndrome and alcoholism. Yet, the precise mechanism by which this enzyme is involved in the pathophysiology of these disorders remains controversial.

Knockout of Slc25a19 causes mitochondrial thiamine pyrophosphate depletion, embryonic lethality, CNS malformations, and anemia.

SLC25A19 mutations cause Amish lethal microcephaly (MCPHA), which markedly retards brain development and leads to alpha-ketoglutaric aciduria. Previous data suggested that SLC25A19, also called DNC, is a mitochondrial deoxyribonucleotide transporter. We generated a knockout mouse model of Slc25a19. These animals had 100% prenatal lethality by embryonic day 12. Affected embryos at embryonic day 10.5 have a neural-tube closure defect with ruffling of the neural fold ridges, a yolk sac erythropoietic failure, and elevated alpha-ketoglutarate in the amniotic fluid. We found that these animals have normal mitochondrial ribo- and deoxyribonucleoside triphosphate levels, suggesting that transport of these molecules is not the primary role of SLC25A19. We identified thiamine pyrophosphate (ThPP) transport as a candidate function of SLC25A19 through homology searching and confirmed it by using transport assays of the recombinant reconstituted protein. The mitochondria of Slc25a19(-/-) and MCPHA cells have undetectable and markedly reduced ThPP content, respectively. The reduction of ThPP levels causes dysfunction of the alpha-ketoglutarate dehydrogenase complex, which explains the high levels of this organic acid in MCPHA and suggests that mitochondrial ThPP transport is important for CNS development.

No difference in blood thiamine diphosphate levels between Swedish Caucasian patients with congestive heart failure treated with furosemide and patients without heart failure.

OBJECTIVES: To determine whether furosemide treatment in congestive heart failure (CHF) patients is associated with thiamine deficiency. DESIGN: Patients without heart failure and without diuretic treatment were included to compare with patients with CHF belonging to New York Heart Association (NYHA) functional class II and III-IV, respectively, and receiving furosemide therapy. SETTING: All patients were recruited from the emergency ward of the cardiology section. Huddinge University Hospital, where they were admitted due to CHF or acute myocardial infarction. SUBJECTS: Ninety-nine patients were included from whom a blood sample was taken, as well as routine admission blood samples for the analysis of thiamine diphosphate (TPP) concentrations. Patients taking vitamin preparations were excluded. MAIN OUTCOME MEASURES: Blood TPP concentrations were measured by high performance liquid chromatography (HPLC) and compared between the patient groups by the use of ANOVA. RESULTS: No significant difference was found between the groups in blood TPP concentrations. CONCLUSIONS: Thiamine deficiency may not be a complication of furosemide treatment in the studied Swedish patient population.

Thiamin and thiamin phosphate ester deficiency assessed by high performance liquid chromatography in four clinical cases of Wernicke encephalopathy.

The concentrations of thiamin and thiamin phosphate esters were determined by high performance liquid chromatography in four patients with clinical Wernicke encephalopathy. Three were alcohol abusers, and one had prolonged vomiting and anorexia. Thiamin and thiamin monophosphate were assessed in plasma and whole blood (four patients) and in cerebrospinal fluid (two patients) before and during thiamin treatment. Thiamin diphosphate was also assessed in whole blood in the four patients. Before treatment, thiamin monophosphate was significantly decreased in all patients, and thiamin diphosphate in three. A poor increase in thiamin mono- and diphosphate was paralleled by a slow clinical improvement in one patient, while an increase in all thiamin compounds was observed in two patients with a rapid recovery. Thiamin monophosphate was a more sensitive marker of deficiency than thiamin diphosphate and unphosphorylated thiamin.

Red cell transketolase studies in a private practice specializing in nutritional correction.

Erythrocyte transketolase (TKA) and thiamin pyrophosphate percentage uptake, or effect (TPPE) were performed on 1011 patients between 1983 and 1986. The subjects were drawn from a private practice specializing in nutritional correction as a major therapeutic thrust. Either TKA or TPPE or both were abnormal in 283 (28%). Out of the total number of patients with these abnormal studies 36 have been selected as representative. Their clinical presentation is correlated with subsequent laboratory testing in order to draw attention to the practical value of the test in a clinical setting. These data are presented because of the surprisingly high incidence of abnormal tests, that strongly suggests that there is widespread marginal nutritional deficiency in the United States and that it represents a clinical problem that deserves far more attention than it is presently receiving.

Encefalopatia de Wernicke: control de la enzima tiamina pirofosfato en sangre, en 30 pacientes con alteración del estado de conciencia, que consultaron en el Departamento de Medicina Interna del Hospital General San Juan de Dios

En nuestro pais, Guatemala, nunca se habia investigado lo que es la encefalopatia de Wernicke que traducido se refiere a la deficiencia de la Tiamina (Vitamina B1)/. Para poder realizar nuestra investigación tomamos una muestra de 30 pacientes, adultos de uno y otro sexo, excluyéndose los pacientes que presentaban alteraciones del estado de conciencia con diagnóstico de hipertensión arterial, accidente cerebro vascular, alcohólicos, abcesos cerebrales, (alcohólicos) o traumatismo cerebral. Que ingresaron por bez primera al hospital sin diagnóstico; al llegar el paciente a la emergencia, inmediatametne se procedió extraer 5 cc de sangre, la que se centrifugaba, se extraia el suero. El cual se hacia reaccionar posteriormente con 4 reactivos (blanco muestra Standar y control) específico para medir el incremento en sangre de la enzima Tiamina pirofosfato (ver metododologia)

Recurrent febrile lymphadenopathy treated with large doses of vitamin B1: report of two cases.

The 2 children whose cases are reported here both had recurrent episodes of fever and cervical lymphadenopathy. The conventional approach had been unsuccessful in identifying the cause or therapy. In neither case was there an infectious agent demonstrated, and biopsy of a pathologically enlarged lymph gland revealed only reactive hyperplasia in each case. Abnormal metabolism was revealed in the first patient by detecting a substance in urine which is reported to be diagnostic for a form of subacute necrotizing encephalomyelopathy. In the second case, red cell transketolase indicated thiamine pyrophosphate deficiency. Both children had elevated concentrations of folate and B12 in serum. Neither of the 2 patients had further episodes when given a clinical trial with large doses of thiamine hydrochloride. Recurrent episodes of febrile lymphadenopathy are extemely frequent in children and spontaneous resolution occurs, while in others there is either proven or assumed infection. Although final proof of therapeutic efficacy is lacking, the rapid improvement and maintenance of health in both children was striking after conventional therapy had failed.

The role of thiamine in nervous tissue.

The possibility that thiamine (vitamin B1) has a role in nervous tissue that is independent of its well-documented coenzyme function is discussed. After reviewing the localization and metabolism of the vitamin and its phosphate esters, the effects of either thiamine deprivation or antimetabolites of thiamine on conduction and transmission, and the relationship between thiamine triphosphate and the genetic, neurological disease, subacute necrotizing encephalomyelopathy (Leigh's disease), it is suggested that despite the lack of hard evidence, it is likely that the vitamin possesses this alternate function.