Thiamine Pyrophosphate Levels Research Articles

1614-P: Metabolomic Profiling Reveals Thiamine-Mediated Regulation of Triglyceride Synthesis and Lipid Turnover in Brown Fat

Brown adipose tissue (BAT) functions as a metabolic sink to dispose glucose as well as fatty acids (FAs) and exerts profound effects on energy and glucose homeostasis. Intermittent fasting (IF) has become an attractive option for combating obesity and treating diabetes, yet how IF regimen impacts BAT metabolism and thermogenic capacity remains poorly understood. Using metabolomics and lipidomic assays, we show that alternate day fasting (ADF) elicited robust activation of upper glycolysis and increased production of glycerol-3-phosphate (G3P) and lactate accompanied with stimulation of glycolytic shunts, pentose phosphate pathway (PPP) and glycogenesis, in BAT but not in gonadal white adipose tissue (gWAT) in feeding state. As a result, feast BAT exhibited a notable increase in triglyceride (TG) synthesis, tissue volume, and thermogenic capacity compared to ad libitum group. Mechanistically, repeated fasting and refeeding suppressed the expression of thiamine transporter ThTr2 and decreased the levels of free thiamine, thiamine pyrophosphate (TPP) and thiamine monophosphate (TMP), in part through periodic activation of mTORC1. Genetic inhibition of mTORC1 in BAT restored expression of ThTr2 and diminished ADF-preserved lipid storage in vivo, and inactivating thiamine metabolism with specific inhibitors induced G3P production and TG synthesis in vitro. Taken together, our study reveals a new mechanism involving thiamine that reprograms BAT carbohydrate metabolism to preserve lipids and improves metabolic health. Disclosure C.Wang: None. X.Zhang: None. M.Liu: None.

The Thiamine-Dependent Hysteretic Behavior of Human Transketolase: Implications for Thiamine Deficiency

We have investigated the hysteretic properties of human transketolase with emphasis on its dependency on thiamine pyrophosphate concentration. As demonstrated previously, the reaction progress curves revealed a slow transition from an initial low velocity to a faster final steady-state velocity, characterized by the rate constant τ-1. The rate of the transition was dependent on the concentration of the thiamine pyrophosphate cofactor, with progressively longer transition times found as the concentration of thiamine pyrophosphate was decreased. At physiological thiamine pyrophosphate concentrations, the inverse rate constant was in the range of 10 to 20 min for fibroblast-derived transketolase and increased dramatically with only small decreases from these levels of thiamine pyrophosphate. Variation in the lag was found when transketolase from different individuals was examined. Moreover, at low levels of thiamine, the rate of the transition was different between fibroblast- and lymphoblast-derived transketolase. The substantial lag in formation of active holoenzyme and the findings of interindividual variation and cell type variation in the lag period suggest mechanisms for the loss of transketolase activity during thiamine deficiency and may explain, at least in part, the differential sensitivity to deficiency demonstrated by tissues and individuals.

Thiamine responsive high output heart failure of adults: an under-recognized entity.

Thiamine deficiency, commonly presenting as dry and wet beriberi, a lesser-known entity in the present era, is increasingly being reported from Kashmir, a north Indian state. The present study aims to present the clinical profile of patients presenting with high-output heart failure (HOHF). Subjects with a primary diagnosis of denovo heart failure and features suggestive of HOHF were recruited; those who responded to intravenous administration of thiamine alone (responders) were adults with no co-morbidities and those who required other medications particularly diuretics (non-responders) were elderly with co-morbidities and underlying heart disease. Responders showed considerably lower mean thiamine pyrophosphate (TPP) levels and higher mean lactate and venous oxygen saturation than non-responders. More importantly, the mean drop in lactate and SVO2 following thiamine therapy was more in responders. In a setting of high risk for thiamine deficiency, features suggestive of HOHF along with elevated lactate and higher venous oxygen saturation, a response to thiamine challenge may serve as surrogate marker of thiamine deficiency.

Thiamine Level in Out-of-hospital Cardiac Arrest Patients

BACKGROUND: Thiamine deficiency is more common in critically ill patients. Administration of thiamine in cardiac arrest mice has improved survival and neurological outcomes. Evidence for thiamine deficiency in cardiac arrest humans is insufficient to support routine use of thiamine in cardiac arrest patients. AIM: This study aimed to determine thiamine blood levels in cardiac arrest patients to understand whether the presence of thiamine deficiency is common in cardiac arrest patients. METHODS: A prospective descriptive study from April 2017 to March 2018, on 24 adult out-of-hospital cardiac arrest patients. We used the high-performance liquid chromatography technique to determine whole blood thiamine pyrophosphate levels in cardiac arrest patients who arrived at the emergency department within 1 h of the onset of a cardiac arrest. RESULTS: The mean thiamine pyrophosphate level within 1 h of the onset of a cardiac arrest was 170.9 ± 56.7 nmol/L. Only one participant had thiamine deficiency according to the cut-off level for thiamine pyrophosphate in whole blood of <70 nmol/L. Fourteen patients had spontaneous return of circulation. Thiamine pyrophosphate levels were not different between the two groups of patients who had and did not have the return of spontaneous circulation at the emergency department. CONCLUSION: Little evidence was found to support thiamine deficiency as a feature among our cardiac arrest patients. A study with a larger population is required for more meaningful statistical analysis. As there is no consensus on cut-off level for thiamine deficiency diagnosis, the level of thiamine pyrophosphate in specific populations should be evaluated to establish reference values.

Identification and functional analysis of novel SLC25A19 variants causing thiamine metabolism dysfunction syndrome 4

BackgroundThiamine metabolism dysfunction syndrome 4 (THMD4, OMIM #613710) is an autosomal recessive inherited disease caused by the deficiency of SLC25A19 that encodes the mitochondrial thiamine pyrophosphate (TPP) transporter. This disorder is characterized by bilateral striatal degradation and progressive polyneuropathy with the onset of fever of unknown origin. The limited number of reported cases and lack of functional annotation of related gene variants continue to limit diagnosis.ResultsWe report three cases of encephalopathy from two unrelated pedigrees with basal ganglia signal changes after fever of unknown origin. To distinguish this from other types of encephalopathy, such as acute necrotizing encephalopathy, exome sequencing was performed, and four novel heterozygous variations, namely, c.169G>A (p.Ala57Thr), c.383C>T (p.Ala128Val), c.76G>A (p.Gly26Arg), and c.745T>A (p.Phe249Ile), were identified in SLC25A19. All variants were confirmed using Sanger sequencing. To determine the pathogenicity of these variants, functional studies were performed. We found that mitochondrial TPP levels were significantly decreased in the presence of SLC25A19 variants, indicating that TPP transport activities of mutated SLC25A19 proteins were impaired. Thus, combining clinical phenotype, genetic analysis, and functional studies, these variants were deemed as likely pathogenic.ConclusionsExome sequencing analysis enables molecular diagnosis as well as provides potential etiology. Further studies will enable the elucidation of SLC25A19 protein function. Our investigation supplied key molecular evidence for the precise diagnosis of and clinical decision-making for a rare disease.

Engineering Allosteric Ribozymes to Detect Thiamine Pyrophosphate in Whole Blood.

Thiamine deficiency contributes to several human diseases including Alzheimer's. As its biologically active form, thiamine pyrophosphate (TPP) has been considered as a potential biomarker for Alzheimer's disease (AD) based on several clinical reports that apparently lower blood TPP levels were found in patients with mild cognitive impairment to AD. However, highly sensitive and high-throughput detection of TPP in biological fluids remains an analytical challenge. Here, we report engineering RNA-based sensors to quantitatively measure TPP concentrations in whole blood samples with a detection limit down to a few nM. By fusing a TPP-specific aptamer with the hammerhead ribozyme for in vitro selection, we isolated an allosteric ribozyme with an EC50 value (68 nM) similar to the aptamer's KD value (50 nM) for TPP, which for the first time demonstrates the possibility to maintain the effector binding affinity of the aptamer in such engineered allosteric RNA constructs. Meanwhile, we developed a new blood sample preparation protocol to be compatible with RNA. By coupling the TPP-induced ribozyme cleavage event with isothermal amplification, we achieved fluorescence monitoring of whole blood TPP levels through the "mix-and-read" operation with high-throughput potential. We expect that the engineered TPP-sensing RNAs will facilitate clinical research on AD as well as other thiamine-related diseases.

The effect of thiaminepyrophosphate levels on mortality and morbidity ın patients with stress hyperglycemia

Background: The aim of this study is to evaluate the thiamine pyrophosphate deficiency and effects on critical illness hyperglycemia in pediatric intensive care. Materials-Methods: 126 critically ill children included to the study which applied to Erciyes University Faculty of Medicine, Department of Pediatric Intensive Care Unit (ICU). Age, sex, diagnosis and presence of malnutrition in admission to ICU; Pediatric risk of Mortality III (PRISM III) and Pediatric Logistic Organ Dysfunction (PELOD) scores; mechanical ventilation and length of stay in ICU was evaluated. Blood glucose, thiamine pyrophosphate, cortisol, insulin, C-peptide, HbA1c level, serum lactate in blood gas were analyzed at the time of application. Results: The patients grouped based on blood glucose levels, the group whose glucose level in blood is more than 150 mg/dl (n:75); PRISM and PELOD scores were high, mechanical ventilation and length of stay in intensive care were longer, thiamine pyrophosphate levels were lower (p<0.001, p=0.005, p=0.008, p<0.001, p<0.01). In case of blood glucose >150 mg/dl (n:51) and thiamine pyrophosphate <180 nmol/l is together; mortality increases 3.342-fold and the case was statistically significant (p=0.014). The group whose glucose level in blood is more than 150 mg/dl respectively, insulin, c-peptide and cortisol levels found high and the findings were statistically significant (p<0.001, p=0.005, p=0.040). Conclusion: Stress hyperglycemia is a common situation seen in critically ill patients as a cause of worse clinical outcomes. Identification of stress hyperglycemia due to thiamine deficiency is difficult but it will shed light on the treatment of critically ill children.

Prevalence of Thiamin Deficiency in Ambulatory Patients with Heart Failure

BackgroundThiamin is a required coenzyme in energy production reactions that fuel myocardial contraction. Therefore, thiamin deficiency (TD) may aggravate cardiac dysfunction in patients with systolic heart failure (HF). ObjectiveTo determine the prevalence of TD in ambulatory participants with HF as well as the relationships between thiamin status and HF severity, dietary thiamin intake, diuretic use, and circulating neurohormones. DesignA cross-sectional study comparing the prevalence of TD in ambulatory patients with HF with that of controls. Demographic, anthropometric, nutrition, medication use, and heart function data were collected from direct interviewing, questionnaires, and medical records. Blood samples were obtained to measure levels of neurohormones and assess TD. Participants/settingFifty age-matched control participants without HF and 100 outpatients with HF and reduced left ventricular function were recruited from clinics at St Michael’s Hospital, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada, between September 2009 and February 2011. Main outcome measuresTo assess TD, erythrocyte thiamin pyrophosphate (TPP) was measured using high-performance liquid chromatography. TD was defined as TPP<6.07 μg/dL (180 nmol/L). Statistical analyses performedPrevalence rates were analyzed using χ2 test. Nonparametric statistics (Jonckheere-Terpstra, Kruskal-Wallis, Spearman’s correlation) were used to assess TPP levels in relation to HF severity, medication use and plasma concentrations of F2-isoprostanes, norepinephrine, and N-terminal pro-brain natriuretic peptide (NT-proBNP). ResultsThere was no significant difference in the prevalence of TD in outpatients with HF (6%) and controls (6%) (P=0.99). No relationship was found between heart function, thiamin intake, use or dose of diuretics, and TD. A positive relationship was observed between erythrocyte TPP and F2-isoprostane levels (rs=0.22, P=0.03) but not between erythrocyte TPP and norepinephrine (P=0.45) and NT-proBNP (P=0.58). ConclusionThe prevalence of TD was low in ambulatory HF participants suggesting that, unlike hospitalized patients, ambulatory patients may be at a low risk for TD.

Appropriate Thiamin Pyrophosphate Levels Are Required for Acclimation to Changes in Photoperiod.

Thiamin pyrophosphate (TPP) is the active form of vitamin B1 and works as an essential cofactor for enzymes in key metabolic pathways, such as the tricarboxylic acid (TCA) cycle and the pentose phosphate pathway. Although its action as a coenzyme has been well documented, the roles of TPP in plant metabolism are still not fully understood. Here, we investigated the functions of TPP in the regulation of the metabolic networks during photoperiod transition using previously described Arabidopsis (Arabidopsis thaliana) riboswitch mutant plants, which accumulate thiamin vitamers. The results show that photosynthetic and metabolic phenotypes of TPP riboswitch mutants are photoperiod dependent. Additionally, the mutants are more distinct from control plants when plants are transferred from a short-day to a long-day photoperiod, suggesting that TPP also plays a role in metabolic acclimation to the photoperiod. Control plants showed changes in the amplitude of diurnal oscillation in the levels of metabolites, including glycine, maltose, and fumarate, following the photoperiod transition. Interestingly, many of these changes are not present in TPP riboswitch mutant plants, demonstrating their lack of metabolic flexibility. Our results also indicate a close relationship between photorespiration and the TCA cycle, as TPP riboswitch mutants accumulate less photorespiratory intermediates. This study shows the potential role of vitamin B1 in the diurnal regulation of central carbon metabolism in plants and the importance of maintaining appropriate cellular levels of thiamin vitamers for the plant's metabolic flexibility and ability to acclimate to an altered photoperiod.

The adaptive regulation of thiamine pyrophosphokinase-1 facilitates malignant growth during supplemental thiamine conditions.

Supplemental levels of vitamin B1 (thiamine) have been implicated in tumor progression. Tumor cells adaptively up-regulate thiamine transport during hypoxic stress. Upon uptake, thiamine pyrophosphokinase-1 (TPK1) facilitates the rapid phosphorylation of thiamine into thiamine pyrophosphate (TPP). However, the regulation of TPK1 during hypoxic stress is undefined. Understanding how thiamine homeostasis changes during hypoxia will provide critical insight into the malignant advantage supplemental thiamine may provide cancer cells. Using Western blot analysis and RT-PCR, we have demonstrated the post-transcriptional up-regulation of TPK1 in cancer cells following hypoxic exposure. TPK1 expression was also adaptively up-regulated following alterations of redox status by chemotherapeutic and antioxidant treatments. Although TPK1 was functionally up-regulated by hypoxia, HPLC analysis revealed a reduction in intracellular TPP levels. This loss was reversed by treatment with cell-permeable antioxidants and corresponded with reduced ROS production and enhanced cellular proliferation during supplemental thiamine conditions. siRNA-mediated knockdown of TPK1 directly enhanced basal ROS levels and reduced tumor cell proliferation. These findings suggest that the adaptive regulation of TPK1 may be an essential component in the cellular response to oxidative stress, and that during supplemental thiamine conditions its expression may be exploited by tumor cells for a redox advantage contributing to tumor progression.

The effect of thiamine and its metabolites on peripheral neuropathic pain induced by cisplatin in rats.

Thiamine pyrophosphate (TPP) is the active metabolite of thiamine. This study aimed to investigate the effects of thiamine and TPP on cisplatin-induced peripheral neuropathic pain (PNP). Male albino Wistar type Rattus norvegicus were divided into six groups (n=6) that received 2 mg/kg cisplatin (CIS), 25 mg/kg thiamine (TM), 2 mg/kg cisplatin+25 mg/kg thiamine (CTM), 25 mg/kg TPP (TPP), 2 mg/kg cisplatin+25 mg/kg TPP (CTPP), or distilled water (healthy group; HG) for 8 days intraperitoneally. Analgesic effect was measured with a Basile Algesimeter. IL-1β, malondialdehyde (MDA), total glutathione (tGSH), thiamine, and TPP were determined in blood samples. Histopathological examinations were performed on removed sciatic nerves. The percent analgesic effects of the CTM and CTPP groups were calculated to be 21.3% and 82.9%, respectively. Increased production of IL-1β and MDA by cisplatin was inhibited by TPP, while it was not inhibited by thiamine. Conversion of thiamine to TPP significantly decreased in the CIS group. Histopathological and biochemical investigations demonstrated that hyperalgesia and sciatic nerve damage developed in the CIS and CTM groups with low TPP levels. These results indicate that cisplatin inhibits the formation of TPP from thiamine, leading to severe PNP. This finding suggests that TPP may be more beneficial than thiamine for the treatment of cisplatin-induced PNP.

Diagnostic Usefulness of Blood Thiamine Levels as Screening Tests for Wernicke’s Encephalopathy in Patients with Alcohol Use Disorder

Objectives ： The purpose of this study was to evaluate the utility in measuring the blood thiamine and thiamine pyrophosphate (TPP) levels as screening tests for Wernicke encephalopathy in patients with alcohol use disorder. Methods ： We analyzed the demographic, clinical and laboratory data from 35 patients with alcohol use disorder. The blood thiamine and TPP levels were acquired at admission prior to initiation of thiamine intravenous (IV) therapy. We examined whether the blood thiamine and TPP levels correlated with clinical symptoms by apply-ing the Caine’s criteria. Patients who met at least one of Caine’s criteria were considered at high risk for Wernicke encephalopathy and were treated with high-dose thiamine IV therapy. Results ： There was no correlation between blood thiamine/TPP levels and clinical symptoms of Wernicke encephalopathy. Clin-ical manifestations of the below-normal TPP-level group were not different from the normal TPP-level group, except that the normal TPP-level group showed a higher revised clinical insti-tute withdrawal assessment for alcohol (CIWA) scores. Conclusion : Measuring blood thiamine/TPP levels was not sensitive as screening tests for Wernicke encephalopathy among patients with alcohol use disorder. High-dose thiamine IV therapy improved the clinical symptoms of Wernicke encephalopathy in patients with alcohol use disorder.Objectives ： The purpose of this study was to evaluate the utility in measuring the blood thiamine and thiamine pyrophosphate (TPP) levels as screening tests for Wernicke encephalopathy in patients with alcohol use disorder. Methods ： We analyzed the demographic, clinical and laboratory data from 35 patients with alcohol use disorder. The blood thiamine and TPP levels were acquired at admission prior to initiation of thiamine intravenous (IV) therapy. We examined whether the blood thiamine and TPP levels correlated with clinical symptoms by apply-ing the Caine’s criteria. Patients who met at least one of Caine’s criteria were considered at high risk for Wernicke encephalopathy and were treated with high-dose thiamine IV therapy. Results ： There was no correlation between blood thiamine/TPP levels and clinical symptoms of Wernicke encephalopathy. Clin-ical manifestations of the below-normal TPP-level group were not different from the normal TPP-level group, except that the normal TPP-level group showed a higher revised clinical insti-tute withdrawal assessment for alcohol (CIWA) scores. Conclusion : Measuring blood thiamine/TPP levels was not sensitive as screening tests for Wernicke encephalopathy among patients with alcohol use disorder. High-dose thiamine IV therapy improved the clinical symptoms of Wernicke encephalopathy in patients with alcohol use disorder.

Molecular mechanisms mediating the adaptive regulation of human colonic thiamine pyrophosphate (TPP) uptake process

Thiamin(vitamin B1) is indispensable for normal cellular metabolism due to itsinvolvement in critical metabolic pathways (e.g., energy metabolism, maintenanceof normal cellular redox state, normal mitochondrial structure and function). Human(mammals) cannot synthesize thiamin, and thus, must obtain the vitamin fromexogenous sources, i. e., diet and gut microbiota. A substantial amount of themicrobiota‐generated thiamin exists in the form of TPP. We have previously shown the existence of a specific and high‐affinity carrier‐mediated uptake process for TPP in human colonocytes (Am J Physiol Gastrointest Liver Physiol. 2012; 303: G389‐95), and have recently determined the molecular identity of the system involved (product of the SLC44A4 gene) (J Biol Chem. 2014; 289: 4405‐16). We have also shown that the colonic TPP uptake process is adaptively regulated by the extracellular substrate level, but nothing is known about the molecular mechanism(s) that mediates this regulation. We addressed this issue in the current investigation using the human colonepithelial NCM460 cells as a model. Maintaining these cells in the presence of high levels of TPP (1 mM) for 2 and 9 days was found to lead to a significant(p ≤ 0.01) reduction in the rate of TPP uptake compared to uptake by cells maintained in the absence of added TPP. While no change in the level of expression of the SLC44A4 mRNA was found in cells maintained for 2 days in the presence of high TPP level [suggesting possible involvement of post translation mechanism(s)], a significant (p ≤ 0.01) decrease in level of SLC44A4 mRNA was found in cells maintained for 9 days. We also observed a decrease in activity of the SLC44A4 promoter in cells maintained for 9 days in high TPP level. The latter was associated with clear histone modifications at the SLC44A4 promoter that involve significant decrease in histone H3K4‐trimethylation and H3K9‐acetylation (euchromatin/activating markers)and a significant increase in histone H3K9‐trimethylation and H3K27‐trimethylation (heterochromatin/repressive markers). While maintaining the cells for 9 days in the presence of high TPP level did not affect the level of expression of the two transcription factors, ELF3 and CREB‐1, that drive the activity of the SLC44A4promoter, their binding to the SLC44A4promoter was decreased as shown by Chip‐qPCR analysis. These studies demonstrate, for the first time, that multiple mechanisms are involved in the adaptive regulation of colonic TPP uptake by extracellular substrate level. At early stages, this regulation involves post‐translational mechanism(s), while long‐term adaptive regulation involves transcriptional and epigenetic mechanisms.Support or Funding InformationSupported by grants from the DVA and the NIH (DK56061 and DK58057).

Thiamine as a neuroprotective agent after cardiac arrest

AimsReduction of pyruvate dehydrogenase (PDH) activity in the brain is associated with neurological deficits in animals resuscitated from cardiac arrest. Thiamine is an essential co-factor of PDH. The objective of this study was to examine whether administration of thiamine improves outcomes after cardiac arrest in mice. Secondarily, we aimed to characterize the impact of cardiac arrest on PDH activity in mice and humans. MethodsAnimal study: Adult mice were subjected to cardiac arrest whereupon cardiopulmonary resuscitation was performed. Thiamine or vehicle was administered 2min before resuscitation and daily thereafter. Mortality, neurological outcome, and metabolic markers were evaluated.Human study: In a convenience sample of post-cardiac arrest patients, we measured serial PDH activity from peripheral blood mononuclear cells and compared them to healthy controls. ResultsAnimal study: Mice treated with thiamine had increased 10-day survival (48% versus 17%, P<0.01) and improved neurological function when compared to vehicle-treated mice. In addition, thiamine markedly improved histological brain injury compared to vehicle. The beneficial effects of thiamine were accompanied by improved oxygen consumption in mitochondria, restored thiamine pyrophosphate levels, and increased PDH activity in the brain at 10 days.Human study: Post-cardiac arrest patients had lower PDH activity in mononuclear cells than did healthy volunteers (estimated difference: ⿿5.8O.D./min/mg protein, P<0.001). ConclusionsThe provision of thiamine after cardiac arrest improved neurological outcome and 10-day survival in mice. PDH activity was markedly depressed in post-cardiac arrest patients suggesting that this pathway may represent a therapeutic target.

OCT1 in hepatic steatosis and thiamine disposition

OCT1 in hepatic steatosis and thiamine disposition

Understanding the role of sulfur–thiamine interaction in the pathogenesis of sulfur-induced polioencephalomalacia in beef cattle

This study examined the role of sulfur (S) in the pathogenesis of S-induced polioencephalomalacia (PEM) in beef cattle in the context of thiamine status and metabolism. Thiamine, thiamine monophosphate (TMP) and thiamine pyrophosphate (TPP) status in rumen fluid, blood and brain tissue were determined in beef heifers fed 2 levels of S [low S (LS) vs. high S (HS)] at 2 forage-to-concentrate ratios (F:C). High S diet did not affect ruminal and blood thiamine status. Interestingly, however, HS diet showed increased brain thiamine levels. No gross or histopathological changes indicative of PEM were detected in the brains of the heifers. Of note, during the course of the present study, we documented an outbreak of S-induced PEM in commercial feedlot steers. Brain thiamine variables in experimental animals fed HS diet were then contrasted with brain thiamine status in PEM affected feedlot steers. Interestingly, in clinically normal animals, exposure to HS diet resulted in increased levels of both TMP and TPP in the brain tissue, in comparison to animals fed LS diet. In contrast, the PEM affected brains showed overall lower levels of thiamine phosphates. It is noteworthy that TPP levels were 36.5% lower, despite 4.9-fold higher free thiamine in PEM brains compared to normal brains. Our results indicate that high dietary S may increase the metabolic demand for TPP, and that animals incapable of maintaining requisite levels of brain TPP are at high risk to develop fulminant cerebrocortical necrosis.

Thiamine and Fatigue in Inflammatory Bowel Diseases: An Open-label Pilot Study

To demonstrate that fatigue and other disorders related to ulcerative colitis and Crohn's disease are the manifestation of an intracellular mild thiamine deficiency and not due to malabsorbtion, augmented requirements, or nutritional factors, and that this dysfunction is curable with high doses of thiamine administered orally or parenterally. In this pilot study, we treated fatigue in eight patients with ulcerative colitis and four patients affected by Crohn's disease from January to April 2011. The patients were recruited through general practitioners' surveys and among personnel and affiliated personnel of the clinic Villa Immacolata. Fatigue was measured using the chronic fatigue syndrome scale, and the determination of thiamine and thiamine pyrophosphate levels in the blood was carried out through blood tests. The levels of thiamine and thiamine pyrophosphate in the blood were normal. All patients were assigned to receive high doses of thiamine orally. Depending upon the body weight of each patient, dosage ranged from 600 mg/day (60 kg) to 1,500 mg/day (90 kg). The chronic fatigue syndrome scale as well as thiamine and thiamine pyrophosphate levels in the blood were measured 20 days after the beginning of the therapy. Ten patients out of twelve showed complete regression of fatigue, while the remaining two patients showed nearly complete regression of fatigue compared to the chronic fatigue syndrome scale scores before therapy. The absence of blood thiamine deficiency and the efficacy of high-dose thiamine in our patients suggest that fatigue is the manifestation of a thiamine deficiency, likely due to a dysfunction of the active transport of thiamine inside the cells, or due to structural enzymatic abnormalities. The administration of large quantities of thiamine increases the concentration in the blood to levels in which the passive transport restores the normal glucose metabolism in all cells and leads to a complete regression of fatigue.

Increased DNA-Glycation in Type 2 Diabetic Patients: The Effect of Thiamine and Pyridoxine Therapy

It is well known that advanced glycation plays an important role in the progression of diabetic complications. Although several studies have been done on protein glycation, studies related to DNA glycation is limited. The aim of this study is primarily to investigate DNA glycation in diabetes mellitus and secondarily to observe the effects of vitamins B(1) and B(6). Patients with diabetes (n=31) were divided into 2 groups as patients with nephropathy (n=17) and without nephro-pathy (n=14). The control group was recruited from age and sex matched healthy individuals (n=30). In the experimental groups, DNA glycation was measured in DNA isolated from leukocytes. HbA(1c), thiamine pyrophosphate (TPP) and pyridoxal 5-phosphate (PLP) levels were determined in whole blood; glucose and insulin levels in plasma. Patients with nephropathy were further divided into 2 groups and were administered either vitamins B(1) + B(6) (n=6) or B(6) (n=11), for 5 months. All the measurements were performed both before and after the vitamin administration period. AGE-DNA levels were found significantly higher in diabetic patients (p<0.05) than the healthy controls. AGE-DNA and PLP levels were negatively correlated in control patients (r= - 0.361, p<0.05). The combined administration of B(1) and B(6) caused a significant decrease in AGE-DNA values (p<0.05). This study shows that the combined administration of vitamins B(1) and B(6) to diabetic nephropathy patients causes a decrease in DNA glycation in leukocytes. Importantly the administration of vitamin B(6) alone did not have such an effect. To our knowledge, these are the first reported findings related to glycation of leukocyte nuclear DNA in diabetic nephropathy.

Acetyl-CoA metabolism in amprolium-evoked thiamine pyrophosphate deficits in cholinergic SN56 neuroblastoma cells

Inhibition of pyruvate (PDHC) and ketoglutarate (KDHC) dehydrogenase complexes induced by thiamine pyrophosphate deficits is known cause of disturbances of cholinergic transmission in the brain, yielding clinical symptoms of cognitive, vegetative and motor deficits. However, particular alterations in distribution of key acetylcholine precursor, acetyl-CoA, in the cholinergic neuron compartment of thiamine pyrophosphate-deficient brain remain unknown. Therefore, the aim of our work was to find out how amprolium-induced thiamine pyrophosphate deficits (TD) affect distribution of acetyl-CoA in the compartment of pure cholinergic neuroblastoma SN56 cells originating from murine septum. Amprolium caused similar concentration-dependent decreases in thiamine pyrophosphate levels in nondifferentiated (NC) and differentiated (DC) cells cultured in low thiamine medium. In such conditions DC displayed significantly greater loss of viability than the NC ones, despite of lesser suppressions of PDHC activities and tetrazolium salt reduction rates in the former. On the other hand, intramitochondrial acetyl-CoA levels in DC were 73% lower than in NC, which explains their greater susceptibility to TD. Choline acetyltransferase activity and acetylcholine content in DC were two times higher than in NC. TD caused 50% decrease of cytoplasmic acetyl-CoA levels that correlated with losses of acetylcholine pool in DC but not in NC. These data indicate that particular sensitivity of DC to TD may result from relative shortage of acetyl-CoA due to its higher utilization in acetylcholine synthesis.

Thiamine biosynthesis in algae is regulated by riboswitches.

In bacteria, many genes involved in the biosynthesis of cofactors such as thiamine pyrophosphate (TPP) are regulated by ribo switches, regions in the 5' end of mRNAs to which the cofactor binds, thereby affecting translation and/or transcription. TPP riboswitches have now been identified in fungi, in which they alter mRNA splicing. Here, we show that addition of thiamine to cultures of the model green alga Chlamydomonas reinhardtii alters splicing of transcripts for the THI4 and THIC genes, encoding the first enzymes of the thiazole and pyrimidine branches of thiamine biosynthesis, respectively, concomitant with an increase in intracellular thiamine and TPP levels. Comparison with Volvox carteri, a related alga, revealed highly conserved regions within introns of these genes. Inspection of the sequences identified TPP riboswitch motifs, and RNA transcribed from the regions binds TPP in vitro. The THI4 riboswitch, but not the promoter region, was found to be necessary and sufficient for thiamine to repress expression of a luciferase-encoding reporter construct in vivo. The pyr1 mutant of C. reinhardtii, which is resistant to the thiamine analogue pyrithiamine, has a mutation in the THI4 riboswitch that prevents the THI4 gene from being repressed by TPP. By the use of these ribo switches, thiamine biosynthesis in C. reinhardtii can be effectively regulated at physiological concentrations of the vitamin.