Thiamine nutritional status and depressive symptoms are inversely associated among older Chinese adults.

Thiamine has been hypothesized to play an important role in mental health; however, few studies have investigated the association between thiamine nutritional status and depression in the general population. Concentrations of free thiamine and its phosphate esters [thiamine monophosphate (TMP) and thiamine diphosphate (TDP)] in erythrocytes were measured by HPLC among 1587 Chinese men and women aged 50-70 y. The presence of depressive symptoms was defined as a Center for Epidemiological Studies Depression Scale score of ≥16. The median erythrocyte concentration (nmol/L) was 3.73 for free thiamine, 3.74 for TMP, and 169 for TDP. The overall prevalence of depressive symptoms was 11.3%. Lower concentrations of all 3 erythrocyte thiamine biomarkers were monotonically associated with a higher prevalence of depressive symptoms: the multivariable adjusted ORs comparing the lowest with the highest quartiles were 2.97 (95% CI = 1.87, 4.72; P-trend < 0.001) for free thiamine, 3.46 (95% CI = 1.99, 6.02; P-trend < 0.001) for TMP, and 1.98 (95% CI = 1.22, 3.21; P-trend = 0.002) for TDP. In conclusion, poorer thiamine nutritional status and higher odds of depressive symptoms were associated among older Chinese adults. This finding should be further investigated in prospective or interventional studies.

High thiamine diphosphate level as a protective factor for Alzheimer's disease.

Objectives Thiamine diphosphate (TDP) is an indispensable coenzyme for three key enzymes in glucose metabolism. Reduced TDP levels in patients with Alzheimer's disease (AD) has been widely demonstrated and is a diagnostic biomarker for the disease. In this study, we further explored the correlation between altered TDP metabolism and AD along with other risk factors. Methods A 1:1 case-control study was employed with 90 AD patients and 90 control subjects with normal-range cognitive abilities as assayed by the Mini Mental Status Evaluation. Age (≤2 years variation), gender, and educational background were strictly matched. Levels of the main thiamine metabolites in whole blood samples, including TDP, thiamine monophosphate, and thiamine, were assayed using high-performance liquid chromatography. Apolipoprotein E genotypes, haemoglobin, and several metabolic factors (fasting glucose, uric acid, triglyceride, and total cholesterol) associated with AD were also measured. Results The odds ratio of TDP level for AD was 0.95 (with TDP level as a continuous variable) or 0.09 (with TDP level as a dichotomized variable with a cut-off value of 99.48 nmol/L). Blood TDP levels were significantly decreased in female AD patients compared to male AD patients. No correlations were identified between TDP levels and several metabolic factors (fasting glucose, uric acid, triglyceride, and total cholesterol). Conclusions TDP is a protective factor for AD and its protective efficacy may be independent of other metabolic factors. The difference of TDP levels between genders may be another possible explanation for the higher prevalence of AD in females.

[Thiamine and its derivates in cattle blood measured by HPLC in healthy animals, in patients suffering from CCN and in their cohorts]. / Analyse von Vitamin B1 und dessen Derivaten im Rinderblut mittels HPLC-Technik bei gesunden, an CCN erkrankten Tieren und deren Kohorten.

The aim of this project was to develop a routine method to measure thiamine and its derivates in blood, to detect the need of vitamin B1-supply in cattle faster and more precise than until now using the transketolase test. For that, thiamine and its derivates (thiaminediphosphate = TDP,-monophosphate = TMP) were analysed in cattle blood by HPLC technique with post-column derivatization. Moreover, the levels in healthy cattle were compared with those in herds with single CCN cases. EDTA-blood-stored up to 10 days by 6 or 20 degrees C- was the most appropriate substrate. Sensitivitiy and specifity were significantly better than (TT, sum of all fractions): 1.95% and 2.10%; thiamine and TMP: 7.02% and 9.17%. The lowest concentration, which could be measured, was 0.5 ng/ml. 72 samples could be analysed daily. In the blood of 280 healthy calves and cows (group A), 201 clinically unsuspicious animals out of stocks with single cases of CCN (group B) and 12 patients with clinical obvious CCN (group C), thiamine and its phosphates were measured and the means calculated (ng/ml). After this, the thiamine status is characterized by (ng/ml): (A) thiamine 13.5 (4.61-28.8),TDP 51.0 (33.1-82.2), TMP 8.79 (2.23-18.1),TT 73.3 (44.6-114); (B) thiamine 8.73 (0.00-20.0), TDP 43.5 (15.5-75.7),TMP 6.15 (0.00-16.6), TT 59.4 (18.7-96.5); (C) thiamine 3.85 (0.00-1 1.5), TDP 14.5 (0.00-28.3), TMP 1.27 (0.00-4.87), TTP 19.6 (4.92-35.9). So, HPLC with post-column derivatization offers a precise, automatically working method for a fast diagnose of thiamine deficiency. The lowest critical value of TT is 40 ng/ml for healthy animals in the blood. The sample (EDTA-blood) can be posted simply at temperatures up to 20 degrees C. In comparison to other measuring methods, this HPLC-technique enables an early recognition of the risk to come down with CCN in endangered cattle herds.

Enhanced Activities of Blood Thiamine Diphosphatase and Monophosphatase in Alzheimer's Disease.

BACKGROUND: Thiamine metabolites and activities of thiamine-dependent enzymes are impaired in Alzheimer's disease (AD). OBJECTIVE: To clarify the mechanism for the reduction of thiamine diphosphate (TDP), an active form of thiamine and critical coenzyme of glucose metabolism, in AD. METHODS: Forty-five AD patients clinically diagnosed and 38 age- and gender-matched control subjects without dementia were voluntarily recruited. The contents of blood TDP, thiamine monophosphate (TMP), and thiamine, as well as the activities of thiamine diphosphatase (TDPase), thiamine monophosphatase (TMPase), and thiamine pyrophosphokinase (TPK), were assayed by high performance liquid chromatography. RESULTS: Blood TDP contents of AD patients were significantly lower than those in control subjects (79.03 ± 23.24 vs. 127.60 ± 22.65 nmol/L, P<0.0001). Activities of TDPase and TMPase were significantly enhanced in AD patients than those in control subjects (TDPase: 1.24 ± 0.08 vs. 1.00 ± 0.04, P < 0.05; TMPase: 1.22 ± 0.04 vs. 1.00 ± 0.06, P < 0.01). TPK activity remained unchanged in AD as compared with that in control (0.93 ± 0.04 vs. 1.00 ± 0.04, P > 0.05). Blood TDP levels correlated negatively with TDPase activities (r = -0.2576, P = 0.0187) and positively with TPK activities (r = 0.2426, P = 0.0271) in all participants. CONCLUSION: Enhanced TDPase and TMPase activities may contribute to the reduction of TDP level in AD patients. The results imply that an imbalance of phosphorylation-dephosphorylation related to thiamine and glucose metabolism may be a potential target for AD prevention and therapy.

The analysis of thiamin and its derivatives in whole blood samples under high pH conditions of the mobile phase.

In this study a protocol for the analysis of thiamin and thiamin coenzymes in whole blood was developed. Thiamin and its coenzymes are analyzed by reversed phase liquid chromatography (RPLC), precolumn derivatisation with alkaline potassium ferricyanide and fluorescence detection, all at pH 10. Under these relatively high pH conditions the detectability of the analytes and the robustness of the method were substantially improved. The use of a high pH resistant RPLC column was a crucial step in developing this analysis method. Reproducibility, linearity, recovery, detection limit and column robustness were investigated. The within-batch CV was <2.5%, the between-batch CV <4.5%. The method was linear far above the physiological relevant concentration level. Recovery was almost 100% on an average. The limit of quantification was 1 nmol/l. The robustness of the RPLC column proved to be very high. Up to 1500 injections hardly any substantial changes in retention times and efficiency were observed. In summary: Using a high pH resistant RPLC column resulted in a robust, sensitive and precise method for the analysis of total Vitamin B1 and especially of TDP.

Thiamin monophosphate in the CSF of patients with amyotrophic lateral sclerosis.

Free thiamin and thiamin monophosphate levels were determined by an electrophoretic fluorometric micromethod in plasma and CSF of patients with amyotrophic lateral sclerosis (ALS), alcoholics, and controls. In plasma of patients with ALS as well as in plasma and CSF of alcholics, both thiamin and thiamin monophosphate concentrations were decreased so that the thiamin-thiamin monophosphate (T/TMP) ratio remained unchanged compared with that of controls. In CSF of patients with ALS, however, thiamin monophosphate values decreased much more than thiamin levels, so that the T/TMP ratio was significantly increased. The selective impairment of thiamin monophosphate production by nerve cells is likely to result from the reduction of the activity of thiamin pyrophosphatase, an enzyme synthetized and highly concentratd in the Golgi complex. Thiamin pyrophosphatase is known to diminish in ALS as well as in experimental motor neuronal degeneration or axotomy. Thus, the T/TMP ratio could be taken as an index of the impairment of neuronal protein synthesis in ALS.

Nervous tissue thiamine metabolism in vivo. I. Transport of thiamine and thiamine monophosphate from plasma to different brain regions of the rat.

The transport of thiamine (T) and thiamine monophosphate (TMP) across the blood-brain barrier was measured in vivo in the rat. Different doses of [14C]T (15-550 nmol) and [14C]TMP (11-110 nmol) were injected into the femoral vein. The content of T and its phosphoesters in blood and brain tissue (cerebellum, pons, medulla and cerebral cortex) 20 s after the injection was determined radiometrically after electrophoretic separation. Blood flow and blood volume in the same regions of the brain was also determined. Both T and TMP entered rapidly the cerebral tissue, where they were found chemically unmodified. The cerebral tissue extracted less than 7% of plasma T. At physiological plasma T concentrations, the rate of transport ranged from 0.43 to 0.65 nmol X g-1 X h-1 with only minor differences among the various regions. T was transported into the nervous tissue by two separate mechanisms: one saturable, that at physiological plasma T levels accounted for 95% (cerebellum) to 91% (cerebral cortex) of the total T taken up, and one non-saturable, that was most efficient in the cerebral cortex. The Km (half-saturation constant) of the former transport mechanism ranged from 1.95 to 2.75 nmol X ml-1 in the 4 areas investigated. Vmax (maximal transport rate) values ranged from 6 to 9 nmol X g-1 X h-1, the highest value being found in the cerebellum. The overall transport rate of TMP was on average 5-10 times as low as that of T and also showed a saturable and a non-saturable component. Both components were slower than those observed for T.

Lipophilic thiamine treatment in long-standing insulin-dependent diabetes mellitus.

Thiamine plays an important role in the regulation of glucose metabolism and pancreatic beta-cell functioning. A role for this vitamin in cellular glucose transport has been indicated in the literature. The aim of this study was to determine whether a lipophilic form of thiamine (benzoyloxymethyl-thiamine, BOM) was able to improve metabolic control in patients with long-standing insulin-dependent diabetes mellitus (type 1). A total of 10 children with type 1 diabetes of long duration (age 11.4 +/- 1.2 years, duration of the disease 4.5 +/- 0.7 years, means +/- SEM) were studied before and after treatment with BOM in a randomized double-blind and placebo-controlled study. Five patients were assigned to the BOM-treated group and five to the placebo-group. In all patients basal and glucagon-stimulated C-peptide secretion was undetectable. Thiamine status was assayed by measuring the plasma content of thiamine and its monophosphate form at entry and after 3 months of treatment. The blood HbA(1C) levels and the daily dose of insulin per kg body weight were assessed in both groups before treatment, after 1 month and 3 months of treatment, then 3 months following its suspension. The plasma content of thiamine + thiamine monophosphate in type 1 diabetic patients (35.3 +/- 3.6 pmol/mL) was significantly lower when compared with that measured in six age-matched normal subjects (53.2 +/- 2.3 pmol/mL, P < 0.05).

Alteration of thiamine pharmacokinetics by end-stage renal disease (ESRD).

OBJECTIVE: In a comparative study with 20 end-stage renal disease (ESRD) patients the pharmacokinetics of two therapeutically used thiamine (vitamin B1) preparations were assessed. SUBJECTS, MATERIAL AND METHODS: After a single oral dose of either 100 mg benfotiamin (S-benzoylthiamine-o-monophosphate, BTMP) or 100 mg thiamine mononitrate (TN), blood levels of thiamine phosphate esters were analyzed by HPLC after precolumn derivatization to thiochrome phosphate esters for a 24-hour period. RESULTS: The pharmacokinetic parameters AUC0-24h, Cmax and tmax of the benfotiamin group in whole blood and plasma exceeded significantly those in the TN group. Only 1.0 vs. 0.6% of the administered dose were excreted in urine in the BTMP group and TN group, respectively. A high cellular efficacy, as was concluded from the short-term stimulation of the thiamine-dependent transketolase activity in erythrocytes (ETKA), was assessed for BTMP as well as TN. The activation coefficient (ETK-AC) decreased significantly from 1.10 to 1.04 vs. 1.12 to 1.07 in both the BTMP as well as TN groups, respectively. In addition, a high transfer rate to thiamine diphosphate (TDP) was observed in the patients after ingestion of BTMP. The TDP concentration in whole blood increased by 2.6 and 1.4 times from baseline levels to Cmax in the BTMP and TN groups, respectively. The AUC0-24h of TDP in whole blood after BTMP ingestion exceeded those after TN ingestion by 420%. CONCLUSION: These findings justify the therapeutic application of BTMP in ESRD, because a high intracellular concentration of TDP may protect against numerous adverse effects of uremia in the long run.

[Characteristic features of 35S-benzoylthiamine monophosphate in albino mice]. / Osobennosti raspredeleniia 35S-benzoiltiaminmonofosfata v organizme belykh myshei.

Equimolar doses (30 mM/kg) of 35S-labelled thiamin, thiamin monophosphate or benzoyl thiamin monophosphate were administered intraperitoneally into mice. Increase in content of labelled metabolites, derived from 35S-benzoyl thiamin monophosphate, as compared with 35S-thiamin and 35S-thiamin monophosphate, was more distinct and prolonged in mice tissues, especially in brain and heart muscle, within 6-24 hrs. In blood this relationship was opposite. Total 35S was excreted with urine also at the highest rate after the 35S-benzoyl thiamin monophosphate administration as compared with the effect of thiamin and thiamin monophosphate but differences between the experimental data obtained with the latter compounds were only slight.

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.

In vivo evidence for alcohol-induced neurochemical changes in rat brain without protracted withdrawal, pronounced thiamine deficiency, or severe liver damage.

Magnetic resonance spectroscopy (MRS) studies in human alcoholics report decreases in N-acetylaspartate (NAA) and choline-containing (Cho) compounds. Whether alterations in brain metabolite levels are attributable to alcohol per se or to physiological effects of protracted withdrawal or impaired nutritional or liver status remains unclear. Longitudinal effects of alcohol on brain metabolites measured in basal ganglia with single-voxel MRS were investigated in sibling pairs of wild-type Wistar rats, with one rat per pair exposed to escalating doses of vaporized alcohol, the other to vapor chamber air. MRS was conducted before alcohol exposure and twice during exposure. After 16 weeks of alcohol exposure, rats achieved average blood alcohol levels (BALs) of approximately 293 mg per 100 ml and had higher Cho and a trend for higher glutamine+glutamate (Glx) than controls. After 24 weeks of alcohol exposure, BALs rose to approximately 445 mg per 100 ml, and alcohol-exposed rats had higher Cho, Glx, and glutamate than controls. Thiamine and thiamine monophosphate levels were significantly lower in the alcohol than the control group but did not reach levels low enough to be considered clinically relevant. Histologically, livers of alcohol-exposed rats exhibited greater steatosis and lower glycogenosis than controls, but were not cirrhotic. This study demonstrates a specific pattern of neurobiochemical changes suggesting excessive membrane turnover or inflammation, indicated by high Cho, and alterations to glutamate homeostasis in the rat brain in response to extended vaporized alcohol exposure. Thus, we provide novel in vivo evidence for alcohol exposure as causing changes in brain chemistry in the absence of protracted withdrawal, pronounced thiamine deficiency, or severe liver damage.

Rapid HPLC measurement of thiamine and its phosphate esters in whole blood.

BACKGROUND: Thiamine (vitamin B(1)) deficiency is associated with severe diseases such as beriberi and Wernicke encephalopathy. Although most Americans have sufficient dietary intake, thiamine deficiency is observed in the alcohol-dependent and elderly populations. Measurement of thiamine concentration in whole blood provides an assessment of vitamin B(1) status in at-risk individuals. METHOD: We used TCA to precipitate proteins in whole blood. Thiamine and its phosphate esters were derivatized using potassium ferricyanide to thiochromes, which were separated by gradient elution on a reversed-phase HPLC column and detected by fluorescence. The method was validated for linearity, limit of quantification, imprecision, accuracy, and interference. Results obtained with this method were compared with those produced by the method currently used in our clinical laboratory. Reference values of thiamine and its phosphate esters were determined in samples obtained from self-reported healthy adults who were not taking vitamin supplements. To shorten analysis time, our method used whole blood rather than washed erythrocytes, did not require lengthy enzymatic dephosphorylation, and had a simple mobile phase. RESULTS: The method was linear to 4000 nmol/L. The lower limit of quantification was 3 nmol/L. The within-run CV was <3.5% and total CV was <9.4%. This method correlated with our current method (r = 0.97). Approximately 90% of the total thiamine content in whole blood was present as thiamine diphosphate (TDP). The means (ranges) for an apparently healthy population were 114 (70-179) nmol/L for TDP and 125 (75-194) nmol/L for total thiamine. Results for separation and measurement of free thiamine and thiamine phosphate esters in whole blood were obtained within 5.5 min. CONCLUSION: We developed an HPLC method that allows separation and measurement of free thiamine and thiamine phosphate esters in whole blood and provides more rapid results than other methods.

High prevalence of low plasma thiamine concentration in diabetes linked to a marker of vascular disease.

AIMS/HYPOTHESIS: To assess thiamine status by analysis of plasma, erythrocytes and urine in type 1 and type 2 diabetic patients and links to markers of vascular dysfunction. METHODS: Diabetic patients (26 type 1 and 48 type 2) with and without microalbuminuria and 20 normal healthy control volunteers were recruited. Erythrocyte activity of transketolase, the concentrations of thiamine and related phosphorylated metabolites in plasma, erythrocytes and urine, and markers of metabolic control and vascular dysfunction were determined. RESULTS: Plasma thiamine concentration was decreased 76% in type 1 diabetic patients and 75% in type 2 diabetic patients: normal volunteers 64.1 (95% CI 58.5-69.7) nmol/l, type 1 diabetes 15.3 (95% CI 11.5-19.1) nmol/l, p < 0.001, and type 2 diabetes 16.3 (95% CI 13.0-9.6) nmol/l, p < 0.001. Renal clearance of thiamine was increased 24-fold in type 1 diabetic patients and 16-fold in type 2 diabetic patients. Plasma thiamine concentration correlated negatively with renal clearance of thiamine (r = -0.531, p < 0.001) and fractional excretion of thiamine (r = -0.616, p < 0.001). Erythrocyte transketolase activity correlated negatively with urinary albumin excretion (r = -0.232, p < 0.05). Thiamine transporter protein contents of erythrocyte membranes of type 1 and type 2 diabetic patients were increased. Plasma thiamine concentration and urinary excretion of thiamine correlated negatively with soluble vascular adhesion molecule-1 (r = -0.246, p < 0.05, and -0.311, p < 0.01, respectively). CONCLUSIONS/INTERPRETATION: Low plasma thiamine concentration is prevalent in patients with type 1 and type 2 diabetes, associated with increased thiamine clearance. The conventional assessment of thiamine status was masked by increased thiamine transporter content of erythrocytes.

Assay values for thiamine or thiamine phosphate esters in whole blood do not depend on the anticoagulant used.

We compared the whole blood, plasma, and erythrocyte (red blood cell (RBC)) concentrations of thiamine and thiamine phosphate esters in the presence of heparin or EDTA as anticoagulants. Three blood specimens were collected from each of 24 healthy volunteers into evacuated collection tubes containing the following anticoagulants: heparin, Na2EDTA, or K2EDTA. The concentrations of nonphosphorylated free thiamine (T), thiamine monophosphate (TMP), thiamine diphosphate (TDP), and thiamine triphosphate (TTP) were determined by the NH2-column HPLC method. The anticoagulant used had no effect on the concentrations obtained in whole blood and plasma of thiamine or any of the above thiamine compounds (P>0.05). RBCs were isolated by centrifugation and washed with isotonic saline, and the cell counts of the washed cells were adjusted to their whole blood values. In the washed RBCs with any anticoagulant, the concentrations of T, TMP, and TDP expressed either as nmol/L of whole blood or a ratio to hemoglobin were significantly lower (P<0.05) than those in whole blood.