Erythrocyte Transketolase Activation Coefficient Research Articles

Protocol and application of basal erythrocyte transketolase activity to improve assessment of thiamine status.

Thiamine (vitamin B1) is an essential micronutrient required as a cofactor in many metabolic processes. Clinical symptoms of thiamine deficiency are poorly defined, hence biomarkers of thiamine status are important. The erythrocyte transketolase activity coefficient (ETKac) is a sensitive measure of thiamine status, but its interpretation may be confounded where the availability of the transketolase enzyme is limited. Basal ETK activity per gram of hemoglobin provides a complementary biomarker of thiamine status; however, its measurement and calculation are poorly described. Here, we describe in detail the assessment of basal ETK activity, including the calculation of path length in microplates and the molar absorption coefficient of NADH specific to the assay, and the measurement of hemoglobin in sample hemolysates. To illustrate the application of the methods, we present ETKac and basal ETK activity from women in The Gambia and UK. In conclusion, we present a clear protocol for the measurement of basal ETK activity that will permit the harmonization of methods to improve replication between laboratories.

Thiamin and riboflavin status with related enzyme activities in pulmonary tuberculosis with diabetes mellitus in Shandong province of China.

Poor nutritional status is a common finding in pulmonary tuberculosis (TB) patients with and without type 2 diabetes mellitus (T2DM), thiamin (VB-1) and riboflavin (VB-2) are coenzymes important for the activation of many enzymes involved in improving nutritional status. We aimed to investigate enzymatic activities and the associations between VB-1 and VB-2, and their relations to nutritional status in TB and TB+T2DM patients. This was a cross-sectional study that prospectively enrolled TB 40 patients with or without T2DM respectively from the Chest Hospital of Qingdao and 76 healthy controls with similar age and gender distributions were recruited from the medical center of the affiliated hospital of Qingdao Medical College. The erythrocyte transketolase activation coefficient (ETKac, for VB-1 deficiency), the glutathione reductase activation coefficient (EGRac, for VB-2 deficiency), and metabolic enzyme activities were analyzed. VB-1 and VB-2 deficiency rates were higher, and enzyme activities were lower in TB and TB+T2DM relative to control group. ETKac and EGRac were negatively correlated with enzyme activities, either with body mass index (BMI), while enzyme activities were positively associated with BMI. VB-1 and VB-2 concentrations were lower in TB patients with or without T2DM relative to controls, with concomitant reductions in the activity levels of key metabolic enzymes. Significant correlations were observed between VB-1 and VB-2 concentrations and the activity of these metabolic enzymes, they all correlated with nutrition status. VB-1 and VB-2 concentrations may thus impact metabolic enzyme activity and thereby influence nutritional status.

Thiamine deficiency in Gambian women of reproductive age.

Thiamine deficiency disorders are associated with a variety of clinical symptoms affecting the nervous and cardiovascular systems. There is growing recognition that thiamine deficiency can occur in populations well beyond the classical region of South Asia, and at‐risk populations include those who receive a large proportion of their energy from polished white rice (or other low‐thiamine staple foods) and with low dietary diversity. Reports of thiamine deficiency in West Africa over the last century have suggested that this has historically been an issue in this population, but in more recent decades, these reports have been limited to prison populations. To understand if thiamine deficiency might be an unrecognized problem in the communities of this region, erythrocyte samples collected during the wet and dry seasons from 226 women of reproductive age (mean age = 28 years old) were assessed for thiamine status by measuring the erythrocyte transketolase activity coefficient (ETKac). Overall, 35.8% of the sample was at high risk of thiamine deficiency (ETKac ≥ 1.25). Risk of thiamine deficiency was significantly higher in the wet (47.9%) compared with the dry season (22.9%) (P < 0.001). To our knowledge, this is the first report of biochemical thiamine deficiency in a free‐living population in West Africa in the 21st century and suggests that further investigation is warranted.

Thiamine Status of Supplemented, Lactating Mothers in Rural Cambodia: A Randomized Controlled Trial

ObjectivesThiamine deficiency is a cause of infant morbidity and mortality throughout Southeast and South Asia. Maternal intake influences human milk thiamine concentrations, thus mother’s intake must be improved to combat infant deficiency. However, the dose of supplemental thiamine required by lactating mothers is unknown. We aimed to estimate the maternal oral thiamine dose required to optimize milk thiamine concentrations, and to investigate the impact of various doses on thiamine status biomarkers. MethodsThis was a double-blind, four-parallel arm randomized controlled dose-response trial. At 2 weeks postpartum, healthy mothers were randomized to consume one capsule daily for 22 weeks, containing either 0 mg (placebo, n = 83), 1.2 mg (estimated average requirement, n = 86), 2.4 mg (n = 81), or 10 mg (n = 85) thiamine. Human milk total thiamine, whole blood thiamine diphosphate, and erythrocyte transketolase activity coefficient (ETKac) were assessed. An Emax curve, estimated using a non-linear least squares model, was plotted for human milk. Linear mixed-effects models were used to test for differences between treatment groups for milk and blood biomarkers. ResultsA maternal supplemental dose of 2.35 (95% CI 0.58, 7.01) mg/d was estimated to reach 90% of the maximum average human milk total thiamine concentration of 191 μg/L. The mean (SD) milk thiamine concentration was significantly higher in all intervention groups (183 (91), 190 (105), and 206 (89) μg/L, for 1.2, 2.4, and 10 mg, respectively) compared to placebo (153 (85) μg/L; p < 0.0001), and did not differ from each other. Blood biomarkers followed similar group trends, except for infant ETKac, where only the 10 mg (mean [SD]: 1.18 [0.10]) and placebo (1.12 [0.06]) groups differed significantly (p = 0.003). ConclusionsWhile an estimated maternal dose of 2.35 (0.58, 7.01) mg/d was required to reach a milk thiamine concentration of 191 μg/L in Emax dose analyses, group comparisons suggest a daily dose of 1.2 mg/d is sufficient to improve maternal biomarkers to levels similar to higher doses (2.4 and 10 mg/d) and consistent with thiamine-replete populations. However, a higher maternal dose of 10 mg/d was required to improve infant ETKac status compared to other dose groups. Funding SourcesBill & Melinda Gates Foundation, The New York Academy of Sciences.

Erythrocyte transketolase activity coefficient (ETKAC) assay protocol for the assessment of thiamine status.

Vitamin B1 (thiamine) is an essential nutrient that acts as a cofactor for a number of metabolic processes, particularly in energy metabolism. Symptoms of classic thiamine deficiency are recognized as beriberi, although clinical symptoms are nonspecific and recognition of subclinical deficiency is difficult. Therefore, reliable biomarkers of thiamine status are required. Thiamine diphosphate is a cofactor for transketolase, including erythrocyte transketolase (ETK). The ETK activity assay as an indirect, functional marker of thiamine status has been used for over 50 years. The ETK activity assay provides a sensitive and specific biomarker of thiamine status; however, there is a lack of consensus over the cutoffs for deficiency, partly due to a lack of assay harmonization. Here, we provide a step‐by‐step protocol for the measurement of ETK activity and the calculation of the ETK activity coefficient, including detailed explanations of equipment and chemicals required and guidance for quality control procedures. Harmonization of the protocol will provide the basis for the development of internationally recognized cutoffs for thiamine insufficiency. The establishment of quality control materials and a quality assurance scheme are recommended to provide reliability. This will ensure that the ETK activity assay remains an important method for the assessment of thiamine status.

Outbreak of Beriberi among African Union Troops in Mogadishu, Somalia

Context and ObjectivesIn July 2009, WHO and partners were notified of a large outbreak of unknown illness, including deaths, among African Union (AU) soldiers in Mogadishu. Illnesses were characterized by peripheral edema, dyspnea, palpitations, and fever. Our objectives were to determine the cause of the outbreak, and to design and recommend control strategies.Design, Setting, and ParticipantsThe illness was defined as acute onset of lower limb edema, with dyspnea, chest pain, palpitations, nausea, vomiting, abdominal pain, or headache. Investigations in Nairobi and Mogadishu included clinical, epidemiologic, environmental, and laboratory studies. A case-control study was performed to identify risk factors for illness.ResultsFrom April 26, 2009 to May 1, 2010, 241 AU soldiers had lower limb edema and at least one additional symptom; four patients died. At least 52 soldiers were airlifted to hospitals in Kenya and Uganda. Four of 31 hospitalized patients in Kenya had right-sided heart failure with pulmonary hypertension. Initial laboratory investigations did not reveal hematologic, metabolic, infectious or toxicological abnormalities. Illness was associated with exclusive consumption of food provided to troops (not eating locally acquired foods) and a high level of insecurity (e.g., being exposed to enemy fire on a daily basis). Because the syndrome was clinically compatible with wet beriberi, thiamine was administered to ill soldiers, resulting in rapid and dramatic resolution. Blood samples taken from 16 cases prior to treatment showed increased levels of erythrocyte transketolase activation coefficient, consistent with thiamine deficiency. With mass thiamine supplementation for healthy troops, the number of subsequent beriberi cases decreased with no further deaths reported.ConclusionsAn outbreak of wet beriberi caused by thiamine deficiency due to restricted diet occurred among soldiers in a modern, well-equipped army. Vigilance to ensure adequate micronutrient intake must be a priority in populations completely dependent upon nutritional support from external sources.

Letters to the editors

Dear Sirs, Mayxay et al. (2007) recently reported that thiamin deficiency (erythrocyte transketolase activity coefficient, α > 1.31) occurs in 12% of 349 patients admitted with uncomplicated malaria, and may contribute to malaria-associated acidosis. Forty-two days after malaria chemotherapy and thiamin supplementation, the prevalence of thiamin deficiency had declined to 3%. As the authors correctly pointed out, it cannot be determined whether this improvement in thiamin status was a consequence of recovery from malaria or thiamin supplementation, or both. In their Figure 1, Mayxay et al. (2007) show that the percentage change in α between admission and day 42 and the α measured at admission were correlated. According to their interpretation, these data suggest that the improvement in thiamin status depends on the degree of thiamin deficiency at baseline. Scatter plot of the percentage change in a between admission a and day 42 and admission a in a computer simulation of 349 persons with random variation in erythrocyte ketolase activity coefficient, a. Two values [coordinates: (0.41; 156.0) and (0.52; 127.5)] that are outside the scale of the graph have been omitted. Relating change with baseline values, however, gives misleading results and consequently incorrect conclusions because of mathematical coupling and regression-to-the-mean effects (Hayes 1988; Tu et al. 2002; Verhoef & West 2005). To show this, the author has used a simulation whereby considering a fictitious population with α values that were normally distributed, with means and SDs as estimated from Figure 1 from the study by Mayxay et al. (2007). The author has used PQRS software (version 3.2; Knypstra 2003) to draw two independent random samples (n = 349) from normally distributed data with means and SDs as described above, and paired the resulting data to compute the change in simulated α values. The results show that the change in α value was negatively related to the baseline values (Figure 1). Such a result is to be expected because, if we have any two sets of random numbers, α0 and α1, and if we plot (α1−α0) on the y-axis and α0 on the x-axis, a negative relation will be observed. This is because −α0 occurs in the y-term and +α0 in the x-term. Regression to the mean occurs because of both measurement errors in α0 and heterogeneity of individual changes in α. Several methods have been proposed to rectify this problem (Tu & Gilthorpe 2007). When using these methods, Mayxay et al. (2007) may find that there is no evidence for the relationship reported.

The nutritional status of women in the first trimester of pregnancy attending an inner-city antenatal department in the UK

We have previously found high rates of poor iron and folate status in women who had delivered a low birthweight baby (LBW) in an ethnically diverse inner-city area of the UK. However, little was known of the nutritional status in the local general obstetric population. We therefore investigated biochemical measures of nutritional status in the first trimester of the first pregnancy. Routine blood samples collected at the antenatal booking clinic were analysed for haemoglobin (Hb), serum ferritin, red cell folate (RCF) (n = 100) and erythrocyte transketolase activation coefficient (ETKAC) for thiamin status (n = 90). We found 9% of women in our sample had a low Hb level, 10% had a low serum ferritin and only one had a low RCF. This is a substantially lower number of women with biochemical deficiencies than we found previously in women three months after delivering a LBW baby. However, 34% had low thiamin status. Thiamin status was negatively correlated with gestational age at birth (r = -0.407, p < 0.001). Differences in nutritional status were observed between ethnic and socio-economic groups. Hb levels differed between ethnic (p = 0.001) and socio-economic groups (p = 0.02), with Africans and women in manual occupations/unwaged having the lowest Hb levels. RCF levels also differed between groups (p < 0.001) with Caucasians and those in non-manual occupations having highest levels. ETKAC also differed between ethnic groups (p = 0.008) with Africans having the highest level indicating a poorer status. The study highlights the need to improve nutrition particularly in ethnic minorities and low income groups who are most at risk of adverse birth outcomes such as LBW.

Bioavailability of water- and lipid-soluble thiamin compounds in broiler chickens.

The bioavailability of thiamin mononitrate, thiamin chloride-hydrochloride and benfotiamin was compared in broiler chickens. A thiamin-deficient diet was supplemented with either 1.8 and 1.5 mg/kg thiamin equivalent as water-soluble salts, or with 1.5 and 1.2 mg/kg thiamin equivalent as benfotiamin, respectively, and fed to 3 replicate groups/treatment for 21 days. Weight gain, feed consumption and feed conversion rate were not significantly affected by solubility or dietary level of thiamin. Likewise, using biochemical indices of thiamin status (erythrocyte transketolase activation coefficient, and thiamin concentrations in blood and liver), no differences were found between the water-soluble thiamin salts, indicating that they have identical potency. In contrast, biochemical indices of thiamin status showed a significantly higher bioavailability for benfotiamin than for the water-soluble sources.

Changes in thiamin, riboflavin, niacin, beta-carotene, vitamins, C, A, D and E status of French Elderly Subjects during the first year of institutionalization.

Vitamin status was assessed in 26 recently institutionalized elderly subjects by combining dietary and biochemical measurements of thiamin, riboflavin, niacin, beta-carotene, vitamins C, A, D and E at admission (P1), and 1.5 (P2), 3.0 (P3), 4.5 (P4), 6.0 (P5), 12 (P6) months later. At admission, except for vitamin A, mean vitamin intakes were lower than the 1992 French Recommended Dietary Allowance. Thiamin, vitamins C, A and E status seemed nearly satisfactory as less than one-fourth of the population sample had blood values lower than the cut-off point for thiamin (erythrocyte thiamin pyrophosphate < 0.17 mumol/l), vitamin A (serum retinol < 1.05 mumol/l), vitamin C (serum vitamin C < 11.3 mumol/l) and vitamin E (serum alpha-tocopherol < 9.3 mumol/l) or higher than the cut-off point for thiamin (erythrocyte transketolase activity coefficient > 1.19). Almost half of the subjects for riboflavin, and almost all non supplemented subjects for vitamin D were in risk of vitamin deficiency (46% had an erythrocyte glutathione reductase activity coefficient > 1.19 and 72% had a plasma 25(OH)D3 < 25 nmol/l). During the study, vitamins status remained unchanged for riboflavin, niacin, vitamins A, D and E, improved for vitamin C (P = 0.004) or impaired for thiamin (P = 0.008). Thus, institutionalization seemed to have no effect on riboflavin, niacin, vitamins A, D and E status and a slight effect on thiamin and vitamin C status.

Metabolic Abnormalities in Fibromyalgia

ABSTRACT Blood investigations (n = 60) have been performed on several groups of female fibromyalgia (FM) patients who ranged in number from 20-to-25, and several groups of matched female controls who ranged in number from 19-to-20. Glycolysis, mitochon-drial respiratory chain, and antioxidant status parameters were assessed in plasma, erythrocytes, and leucocytes. Erythrocyte-transketolase and leucocyte-pyruvate dehydrogenase affinity for their coenzyme, as well as nitric oxide, citrulline and thiols were significantly (P < 0.01) decreased. Protein carbonyles were significantly (P < 0.01) increased. Less significant abnormalities (P < 0.05) were observed in erythrocyte-ATP, leucocyte-NAD, lactate production, lacticodehy-drogenase muscular isoenzymes, catalase, glutathione, taurine (decreased) and erythrocyte-transketolase activity coefficient, pyruvate or acyl carnitine/free carnitine ratio (increased). Mitochondrial respiratory chain was unchanged. Our findings are in line with investigations with nuclea...

Étude des transcétolases et des gluthation réductases au cours de la maladie d'Alzheimer

Erythrocyte transketolase activity coefficient (AC) and affinity for coenzyme (Km) are significantly increased in 16 patients with senile dementia of Alzheimer's type, whereas gluthation reductase AC and Km are unchanged.

Dietary and Biochemical Indices of Nutritional Status in Male Athletes and Controls

To determine whether physical exercise affects biochemical indices of nutritional status, we compared four groups of male athletes (total n = 427) with two control groups (n = 150). Data about their nutrient intake for 1 month were obtained from a 122-item food frequency questionnaire. An estimate for leisure energy expenditure (EE) was calculated from a 15-item physical activity questionnaire. Athletes were grouped according to their EE (ModEE and HighEE athletes) and weight (light = less than 75 kg; heavy = greater than or equal to 75 kg), and controls according to their weight. Mean energy intake in ModEE and HighEE athletes was 2805-3260 kcal/day. Leisure EE significantly (p less than 0.0001) affected energy and nutrient intakes. Energy, riboflavin and calcium intakes were also higher in heavy subjects (P = 0.0006-0.03). The estimated percentage of subjects with deficient dietary intakes, calculated from probability analyses, was 0-6, depending on group and nutrient. Erythrocyte transketolase activation coefficient (E-TKAC) was highest in controls (1.17 +/- 0.0008; p = 0.001). Serum magnesium was highest (p = 0.01) in ModEE athletes (0.85 +/- 0.006 mmol/L). No intergroup differences were found for plasma ascorbic acid, serum zinc or serum ferritin concentration, whereas blood hemoglobin was lowest (p less than 0.001) in HighEE athletes (149 +/- 0.5 g/L). Ten percent of the control subjects had E-TKAC greater than 1.24. Percentage of other values outside reference range was 0-4, depending on group and indicator. Since lowered blood hemoglobin concentration can be explained by hemodilution, we conclude that sports training did not have a negative effect on biochemical indices of thiamin, vitamin C, magnesium, iron, or zinc status in Finnish male athletes.

The distribution of supposed indicators of nutritional status in elderly patients.

The results of a survey of indicators of nutritional status in patients on admission to wards in the Department of Health Care of the Elderly in Nottingham are reported. Results outside conventional limits of normality are common. Little or none of the observed variance in the biochemical indicators in this population is explained by age or sex. Weight, mid-arm circumference, triceps skinfold thickness, albumin, retinol binding protein and retinol tend to be lower in patients who subsequently die, in patients who are clinically classified as thin or wasted, in patients with poor appetites and in patients with a diagnosis of malignancy. Plasma vitamin C, erythrocyte glutathione reductase activation coefficient and erythrocyte transketolase activation coefficient do not show these trends and are likely to be determined by different factors.