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

Protocol for a seamless phase 2A-phase 2B randomized double-blind placebo-controlled trial to evaluate the safety and efficacy of benfotiamine in patients with early Alzheimer's disease (BenfoTeam)

BACKGROUND

Benfotiamine provides an important novel therapeutic direction in Alzheimer's disease (AD) with possible additive or synergistic effects to amyloid targeting therapeutic approaches.

OBJECTIVE

To conduct a seamless phase 2A-2B proof of concept trial investigating tolerability, safety, and efficacy of benfotiamine, a prodrug of thiamine, as a first-in-class small molecule oral treatment for early AD.

METHODS

This is the protocol for a randomized, double-blind, placebo-controlled 72-week clinical trial of benfotiamine in 406 participants with early AD. Phase 2A determines the highest safe and well-tolerated dose of benfotiamine to be carried forward to phase 2B. During phase 2A, real-time monitoring of pre-defined safety stopping criteria in the first approximately 150 enrollees will help determine which dose (600 mg or 1200 mg) will be carried forward into phase 2B. The phase 2A primary analysis will test whether the rate of tolerability events (TEs) is unacceptably high in the high-dose arm compared to placebo. The primary safety endpoint in phase 2A is the rate of TEs compared between active and placebo arms, at each dose. The completion of phase 2A will seamlessly transition to phase 2B without pausing or stopping the trial. Phase 2B will assess efficacy and longer-term safety of benfotiamine in a larger group of participants through 72 weeks of treatment, at the selected dose. The co-primary efficacy endpoints in phase 2B are CDR-Sum of Boxes and ADAS-Cog13. Secondary endpoints include safety and tolerability measures; pharmacokinetic measures of thiamine and its esters, erythrocyte transketolase activity as blood markers of efficacy of drug delivery; ADCS-ADL-MCI; and MoCA.

CONCLUSION

The BenfoTeam trial utilizes an innovative seamless phase 2A-2B design to achieve proof of concept. It includes an adaptive dose decision rule, thus optimizing exposure to the highest and best-tolerated dose.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT06223360, registered on January 25, 2024. https://classic.clinicaltrials.gov/ct2/show/NCT06223360.

Nystagmus in a child with nephrotic syndrome

We report a child with steroid-dependent nephrotic syndrome presenting with excessive irritability, double vision and inability to walk for 5 days. On examination, the child was irritable with Glasgow coma sccale (GCS of 12/15, had bilateral convergent squint (R>L), vertical nystagmus, ataxia without any focal neurological deficits and normal fundus. MRI brain with venogram showed bilateral symmetric FLAIR hyperintensity in the medial thalamus and periaqueductal grey matter showing diffuse restriction with normal venogram. A possibility of Wernicke encephalopathy (WE) was considered and the child was started on thiamine supplementation, following which he had significant improvement in his symptoms. His irritability reduced with significant improvement in the range of eye movements and vertical nystagmus. At 3-month follow-up, the child is asymptomatic with normal gait. Although WE is uncommon in children with nephrotic syndrome, the possibility has to be kept in mind when a child presents with atypical neurological symptoms.

Risk factors for anaemia among women and their young children hospitalised with suspected thiamine deficiency in northern Lao PDR

Anaemia among women and young children remains a major public health concern. This secondary study describes the anaemia prevalence among young hospitalised children and their mothers in northern Lao People's Democratic Republic and explores possible nutritional causes and risk factors for anaemia. Hospitalised children (ages 21 days to <18 months) with clinical symptoms suggestive of thiamine deficiency disorders were eligible along with their mothers. Venous blood was collected for determination of haemoglobin, ferritin, soluble transferrin receptor (sTfR), retinol-binding protein (RBP), erythrocyte glutathione reductase activation coefficient (EGRac), thiamine diphosphate (ThDP) and acute phase proteins. Risk factors for anaemia were modelled using minimally adjusted logistic regression controlling for age. Haemoglobin results were available for 436 women (mean ± SD age 24.7 ± 6.4 years; 1.6% pregnant) and 427 children (4.3 ± 3.5 months; 60.3% male). Anaemia prevalence (Hb < 120 g/L for nonpregnant women and <110 g/L for pregnant women and children) was 30.7% among women and 55.2% among children. In bivariate analyses, biomarkers significantly associated with anaemia in women were ferritin, sTfR, RBP, EGRac and ThDP. Other risk factors for women were lower BMI, mid-upper arm circumference < 23.5 cm, lower education, lower socioeconomic index, food insecurity, Hmong ethnicity, not/rarely having attended antenatal care, not having taken antenatal iron-containing supplements and not meeting minimum dietary diversity. Risk factors for anaemia among children were older age, male sex, stunting, sTfR, ThDP and alpha-1-acid-glycoprotein. Anaemia was common among women and their hospitalised children and was associated with micronutrient deficiencies and socioeconomic, dietary and health care-seeking risk factors, suggesting that multiple strategies are required to prevent anaemia among women and children.

Nutritional peripheral neuropathies

Nutritional peripheral neuropathies are a global problem, heavily influenced by geopolitical, cultural and socioeconomic factors. Peripheral neuropathy occurs most frequently secondary to B-vitamin deficiencies, which is suspected to increase in years to come due to the popularity of vegan and vegetarian diets and increased use of bariatric surgery.This review will focus on the common B-vitamins for which a causal link to peripheral neuropathy is more established (vitamins B1, B2, B6, B9 and B12). We will review the historical human and animal data on which much of the clinical descriptions of vitamin deficiencies are based and summarise current available tools for accurately diagnosing a nutritional deficiency. We will also review recently described genetic diseases due to pathogenic variants in genes involved in B-vitamin metabolism that have helped to inform the phenotypes and potential causality of certain B-vitamins in peripheral neuropathy (B2 and B9).Endemic outbreaks of peripheral neuropathy over the last two centuries have been linked to food shortages and nutritional deficiency. These include outbreaks in Jamaican sugar plantation workers in the nineteenth century (Strachan's syndrome), World War two prisoners of war, Cuban endemic neuropathy and also Tanzanian endemic optic neuropathy, which remains a significant public health burden today. An improved understanding of lack of which vitamins cause peripheral neuropathy and how to identify specific deficiencies may lead to prevention of significant and irreversible disability in vulnerable populations.

Correlation of Fasting Blood Sugar and Glycated Hemoglobin (HbA1c) With Thiamine Levels in Diabetic Patients

Introduction It has been discovered that low levels of thiamine reserves in the body are related to diabetes mellitus (DM) because thiamine directly influences carbohydrate metabolism. Therefore, the purpose of this study was to assess several metabolic variables and blood thiamine levels in patients with type 1 and type 2 DM and compare them with those in a control group of healthy individuals. Methods This case-control study was conducted at multiple diabetic outpatient centers in Karachi. A total of 90 participants, who were divided into three groups, each containing 30 individuals, were chosen using a convenient non-probability sampling technique. Group A served as the control group and consisted of healthy, non-diabetic individuals. Groups B and C contained subjects with type 1 and type 2 DM, respectively. Descriptive analysis was reported as mean standard deviation, whereas gender and comorbidities were expressed as frequencies and percentages. The chi-square test and Pearson's correlation coefficient were used to determine the associations of the variables with type 1 DM, type 2 DM, and controls. Results The study results revealed statistically significant differences between controls, type 1 and type 2 DM, in the means of blood glucose levels and all lipid profiles, such as glycated hemoglobin (HbA1c), fasting blood sugar (FBS), random blood sugar (RBS), serum thiamine, triglycerides (p < 0.001), high-density lipoprotein (HDL) (p = 0.014), and total cholesterol (p = 0.013). Furthermore, it was shown that among the control group, type 1 and type 2 DM, HbA1c, and FBS were insignificantly correlated with thiamine levels, whereas the HbA1c and FBS of the combined diabetic groups were significantly correlated with the thiamine level (r = 0.465, p < 0.001) and (r = 0.360, p = 0.005), respectively, where 'r' is the Pearson correlation coefficient. Additionally, HbA1c and FBS in the combined three groups were significantly correlated with the thiamine level (r = -0.626, p < 0.001) and (r = -0.561, p < 0.001), respectively. Conclusion This study concluded that patients with type 1 and type 2 DM had significantly higher levels of FBS, RBS, HbA1c, triglycerides, and total cholesterol than controls. Furthermore, both type 1 and type 2 DM patients' serum thiamine and HDL levels were observed to be considerably lower than those of controls. Additionally, among both types of DM and controls, there was a strong correlation between FBS and HbA1c. Therefore, we recommend that serum thiamine levels be routinely monitored in diabetic patients, and thiamine supplementation should be considered to avoid complications, especially vascular complications of DM.

Wernicke's Encephalopathy in a Patient With Crohn's Disease: A Case Report

The inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic inflammatory disorders of the intestine. Both are associated with intestinal and extra-intestinal manifestations (EIM). EIM are usually related to intestinal disease activity and may precede or develop concurrently with intestinal symptoms. Although they are well documented, the association of CD with neurological and neuromuscular involvement is rare and controversial, with sporadic and contradictory data regarding its prevalence and spectrum. Neurological involvement can affect the central or peripheral nervous system, with thrombotic events being the most frequent complication. Wernicke's encephalopathy (WE) is one of the neurological complications that occurs in the general population with a clinical prevalence ranging from 0.04% to 0.13%. Although no specific data exists for IBD patients, it is imperative for clinicians to be vigilant and consider the possibility of this condition even with mild neurological symptoms and to administer vitamin B1 promptly before attempting any biological assessment. Timely treatment is essential to avoid irreversible damage or even the death of the patient. We report herein a challenging case of WE in CD and we discuss the literature.

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.

Ataxias: Hereditary, Acquired, and Reversible Etiologies

A variety of etiologies can cause cerebellar dysfunction, leading to ataxia symptoms. Therefore, the accurate diagnosis of the cause for cerebellar ataxia can be challenging. A step-wise investigation will reveal underlying causes, including nutritional, toxin, immune-mediated, genetic, and degenerative disorders. Recent advances in genetics have identified new genes for both autosomal dominant and autosomal recessive ataxias, and new therapies are on the horizon for targeting specific biological pathways. New diagnostic criteria for degenerative ataxias have been proposed, specifically for multiple system atrophy, which will have a broad impact on the future clinical research in ataxia. In this article, we aim to provide a review focus on symptoms, laboratory testing, neuroimaging, and genetic testing for the diagnosis of cerebellar ataxia causes, with a special emphasis on recent advances. Strategies for the management of cerebellar ataxia is also discussed.

Maternal preconception circulating blood biomarker mixtures, child behavioural symptom scores and the potential mediating role of neonatal brain microstructure: the S-PRESTO cohort

Human brain development starts in the embryonic period. Maternal preconception nutrition and nutrient availability to the embryo may influence brain development at this critical period following conception and early cellular differentiation, thereby affecting offspring neurodevelopmental and behavioural disorder risk. However, studying this is challenging due to difficulties in characterizing preconception nutritional status and few studies have objective neurodevelopmental imaging measures in children. We investigated the associations of maternal preconception circulating blood nutrient-related biomarker mixtures (~15 weeks before conception) with child behavioural symptoms (Child Behaviour Checklist (CBCL), aged 3 years) within the Singapore Preconception Study of Long-Term Maternal and Child Outcomes (S-PRESTO) study. The CBCL preschool form evaluates child behaviours based on syndrome scales and Diagnostic and Statistical Manual of Mental Disorders (DSM) oriented scales. These scales consist of internalizing problems, externalizing problems, anxiety problems, pervasive developmental problems, oppositional defiant, etc. We applied data-driven clustering and a method for modelling mixtures (Bayesian kernel machine regression, BKMR) to account for complex, non-linear dependencies between 67 biomarkers. We used effect decomposition analyses to explore the potential mediating role of neonatal (week 1) brain microstructure, specifically orientation dispersion indices (ODI) of 49 cortical and subcortical grey matter regions. We found that higher levels of a nutrient cluster including thiamine, thiamine monophosphate (TMP), pyridoxal phosphate, pyridoxic acid, and pyridoxal were associated with a higher CBCL score for internalizing problems (posterior inclusion probability (PIP) = 0.768). Specifically, thiamine independently influenced CBCL (Conditional PIP = 0.775). Higher maternal preconception thiamine level was also associated with a lower right subthalamic nucleus ODI (P-value = 0.01) while a lower right subthalamic nucleus ODI was associated with higher CBCL scores for multiple domains (P-value < 0.05). One potential mechanism is the suboptimal metabolism of free thiamine to active vitamin B1, but additional follow-up and replication studies in other cohorts are needed.

Alcohol Withdrawal Is an Oxidative Stress Challenge for the Brain: Does It Pave the Way toward Severe Alcohol-Related Cognitive Impairment?

Alcohol use is a leading cause of mortality, brain morbidity, neurological complications and minor to major neurocognitive disorders. Alcohol-related neurocognitive disorders are consecutive to the direct effect of chronic and excessive alcohol use, but not only. Indeed, patients with severe alcohol use disorders (AUD) associated with pharmacological dependence suffer from repetitive events of alcohol withdrawal (AW). If those AW are not managed by adequate medical and pharmacological treatment, they may evolve into severe AW, or be complicated by epileptic seizure or delirium tremens (DT). In addition, we suggest that AW favors the occurrence of Wernicke’s encephalopathy (WE) in patients with known or unknown thiamine depletion. We reviewed the literature on oxidative stress as a core mechanism in brain suffering linked with those conditions: AW, epileptic seizure, DT and WE. Thus, we propose perspectives to further develop research projects aiming at better identifying oxidative stress brain damage related to AW, assessing the effect of repetitive episodes of AW, and their long-term cognitive consequences. This research field should develop neuroprotective strategies during AW itself or during the periwithdrawal period. This could contribute to the prevention of severe alcohol-related brain damage and cognitive impairments.

Pharmacological thiamine levels as a therapeutic approach in Alzheimer's disease

of the study.

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.

Hiding in Plain Sight: Modern Thiamine Deficiency

Thiamine or vitamin B1 is an essential, water-soluble vitamin required for mitochondrial energetics—the production of adenosine triphosphate (ATP). It is a critical and rate-limiting cofactor to multiple enzymes involved in this process, including those at the entry points and at critical junctures for the glucose, fatty acid, and amino acid pathways. It has a very short half-life, limited storage capacity, and is susceptible to degradation and depletion by a number of products that epitomize modern life, including environmental and pharmaceutical chemicals. The RDA for thiamine is 1.1–1.2 mg for adult females and males, respectively. With an average diet, even a poor one, it is not difficult to meet that daily requirement, and yet, measurable thiamine deficiency has been observed across multiple patient populations with incidence rates ranging from 20% to over 90% depending upon the study. This suggests that the RDA requirement may be insufficient to meet the demands of modern living. Inasmuch as thiamine deficiency syndromes pose great risk of chronic morbidity, and if left untreated, mortality, a more comprehensive understanding thiamine chemistry, relative to energy production, modern living, and disease, may prove useful.

A fresh look at thiamine deficiency-new analyses by the global thiamine alliance

Severe thiamine (vitamin B₁ ) deficiency is generally regarded as a problem affecting mostly infants in low-income communities of Southeast Asia and adult alcoholics regardless of their location. However, recent scholarship shows that the disorders associated with thiamine deficiency may also affect heretofore unsuspected populations, and that the scope of disorders, including some long-lasting neurocognitive consequences, is broader than previously thought.

Low-dose thiamine supplementation of lactating Cambodian mothers improves human milk thiamine concentrations: a randomized controlled trial

BACKGROUND

Infantile beriberi-related mortality is still common in South and Southeast Asia. Interventions to increase maternal thiamine intakes, and thus human milk thiamine, are warranted; however, the required dose remains unknown.

OBJECTIVES

We sought to estimate the dose at which additional maternal intake of oral thiamine no longer meaningfully increased milk thiamine concentrations in infants at 24 wk postpartum, and to investigate the impact of 4 thiamine supplementation doses on milk and blood thiamine status biomarkers.

METHODS

In this double-blind, 4-parallel arm randomized controlled dose-response trial, healthy mothers were recruited in Kampong Thom, Cambodia. At 2 wk postpartum, women were randomly assigned to consume 1 capsule, containing 0, 1.2 (estimated average requirement), 2.4, or 10 mg of thiamine daily from 2 through 24 weeks postpartum. Human milk total thiamine concentrations were measured using HPLC. An Emax curve was plotted, which was estimated using a nonlinear least squares model in an intention-to-treat analysis. Linear mixed-effects models were used to test for differences between treatment groups. Maternal and infant blood thiamine biomarkers were also assessed.

RESULTS

In total, each of 335 women was randomly assigned to1 of the following thiamine-dose groups: placebo (n = 83), 1.2 mg (n = 86), 2.4 mg (n = 81), and 10 mg (n = 85). The estimated dose required to reach 90% of the maximum average total thiamine concentration in human milk (191 µg/L) is 2.35 (95% CI: 0.58, 7.01) mg/d. The mean ± SD milk thiamine concentrations were 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 with the placebo group (153 ± 85 µg/L; P < 0.0001) and did not significantly differ from each other.

CONCLUSIONS

A supplemental thiamine dose of 2.35 mg/d was required to achieve a milk total thiamine concentration of 191 µg/L. However, 1.2 mg/d for 22 wk was sufficient to increase milk thiamine concentrations to similar levels achieved by higher supplementation doses (2.4 and 10 mg/d), and comparable to those of healthy mothers in regions without beriberi. This trial was registered at clinicaltrials.gov as NCT03616288.

Infantile thiamine deficiency in South and Southeast Asia: An age-old problem needing new solutions

Infantile beriberi, a potentially fatal disorder caused by thiamine deficiency, is often viewed as a disease confined to history in regions of the world with predominant white rice consumption. Recent case reports have, however, highlighted the persistence of thiamine deficiency as a cause of infant mortality in South and Southeast Asia. Low infant thiamine status and incidence of beriberi is attributable to maternal thiamine deficiency and insufficient breast milk thiamine. Poor dietary diversity, food preparation and cooking practices and traditional post‐partum food restrictions likely play a role in these high‐risk regions. Given the contribution of thiamine deficiency to infant mortality and emerging evidence of long‐lasting neurodevelopmental deficits of severe and even subclinical deficiency in early life, public health strategies to prevent thiamine deficiency are urgently needed. However, efforts are hampered by uncertainties surrounding the identification and assessment of thiamine deficiency, due to the broad non‐specific clinical manifestations, commonly referred to as thiamine deficiency disorders (TDD), that overlap with other conditions resulting in frequent misdiagnosis and missed treatment opportunities, and secondly the lack of readily available and agreed upon biomarker analysis and cut‐off thresholds. This review will discuss the key challenges and limitations in the current understanding of TDD and explore how ongoing initiatives plan to fill persistent knowledge gaps, namely in the development of a standardised case definition to help more accurately diagnose and treat TDD in low‐resource settings. Given more attention and ensuring greater recognition of TDD will support the design and implementation of treatment and prevention programmes, and ensure beriberi can truly be considered ‘the forgotten disease of Asia’.