Effect of knocking out mouse Slc44a4 on colonic uptake of the microbiota-generated thiamine pyrophosphate and colon physiology

Humans and mammals obtain vitamin B1 from dietary and gut microbiota sources. A considerable amount of the microbiota-generated vitamin exists in the form of thiamine pyrophosphate (TPP), and colonocytes are capable of absorbing TPP via a specific carrier-mediated process that involves the colonic TPP transporter (cTPPT encoded by SLC44A4). Little is known about the relative contribution of the SLC44A4 transporter toward total colonic carrier-mediated TPP uptake and its role in colon physiology. To address these issues, we generated an Slc44a4 knockout (KO) mouse model (by Cre-Lox recombination) and found a near-complete inhibition in colonic carrier-mediated [3H]TPP uptake in the Slc44a4 KO compared with wild-type (WT) littermates. We also observed a significant reduction in KO mice's body weight and a shortening of their colon compared with WT. Using RNAseq and Ingenuity pathway analysis (IPA) approaches, we found that knocking out the colonic Slc44a4 led to changes in the level of expression of many genes, including upregulation in those associated with intestinal inflammation and colitis. Finally, we found that the Slc44a4 KO mice were more susceptible to the effect of the colitogenic dextran sodium sulfate (DSS) compared with WT animals, a finding that lends support to the recent prediction by multiple genome-wide association studies (GWAS) that SLC44A4 is a possible colitis susceptibility gene. In summary, the results of these investigations show that Slc44a4 is the predominant or only transporter involved in the colonic uptake of TPP, that the transporter is important for colon physiology, and that its deletion increases susceptibility to inflammation.NEW & NOTEWORTHY This study shows that Slc44a4 is the predominant or only transport system involved in the uptake of the gut microbiota-generated thiamine pyrophosphate (TPP) in the colon and that its deletion affects colon physiology and increases its susceptibility to inflammation.

Thiamine deficiency in diabetes, obesity and bariatric surgery: Recipes for diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a life-threatening condition affecting individuals with diabetes characterised by hyperglycaemia, metabolic acidosis and ketonemia. The incidence and financial burden of DKA is still high. Thiamine deficiency is well documented in patients with DKA and could be associated with cardiac dysfunction in those patients. Thiamine deficiency leads to cardiac dysfunction, neuronal death and worsens the prognosis of DKA. There is an existing metabolic relationship between thiamine deficiency in diabetes, obesity and bariatric surgery. Careful monitoring of thiamine, along with other vitamins, is essential for diabetic patients, obese individuals and postbariatric surgery. Further research and clinical studies are urgently needed to assess the following: (1) Whether diabetes, obesity and bariatric surgery make individuals more prone to have DKA related to thiamine deficiency and (2) Whether supplementation of thiamine can protect diabetic patients, obese subjects and individuals undergoing bariatric surgery from DKA. This review summarises the biochemistry of thiamine and the existing metabolic relationships between thiamine deficiency in DKA, diabetes, obesity and bariatric surgery. Primary and family physicians have an important role in ensuring adequate replacement of thiamine in individuals with diabetes, obesity and bariatric surgery.

ERK1/2 modulation in the central nervous system of male and female thiamine-deficient mice with amprolium

Thiamine deficiency experimental models focus on using the pyrithiamine analog in male rodents, making the thiamine deficiency effects in females and the use of other thiamine antagonists, such as amprolium, unknown. We investigated the impact of thiamine deficiency with amprolium in the cerebral cortex and thalamus of male and female mice by evaluating the modulation of ERK1/2 phosphorylation. The animals were exposed for 20 days to thiamine-deficient chow with different doses of amprolium (20, 40, 60 and 80 mg/kg) and at different treatment periods (five, 10, 15 or 20 days) at a dose of 60 mg/kg. After treatments, ERK1/2 phosphorylation was analyzed by western blot. In male mice, we observed a progressive increase in ERK1/2 phosphorylation in both the cerebral cortex and thalamus in response to the dose of amprolium. In females, ERK1/2 phosphorylation did not progressively increase in response to the amprolium dosage. However, an increase in phosphorylation at the higher doses of 60 and 80 mg/kg was observed. We observed a more intense increase in ERK1/2 phosphorylation in males' cerebral cortex and thalamus from 10 days onwards. In females, the ERK1/2 modulation profiles were similar. The results show that thiamine deficiency induction with amprolium is efficient, compatible with other recognized models that use pyrithiamine, showing changes in cell signaling in the nervous system. The study showed differences in response to thiamine deficiency with amprolium between male and female mice in relation to ERK1/2 phosphorylation and demonstrated that females respond positively to the method and can also be used as model animals.

Thiamine and benfotiamine: Focus on their therapeutic potential

Thiamine, also known as vitamin B1, is an essential nutrient that plays a crucial role in energy metabolism and overall health. It is a water-soluble vitamin that plays an important role in the conversion of carbohydrates into energy in the body. Thiamine is essential for the proper functioning of the nervous system, heart and muscles. Thiamine deficiency is a life-threatening disease that leads to various disorders and lesions in the nerves and brain, at least in vertebrates. Several thiamine precursors with higher bioavailability have been developed to compensate for thiamine deficiency, including benfotiamine. Benfotiamine is more bioavailable and has higher tissue penetration than thiamine. Studies have shown its antioxidant and anti-inflammatory potential in activated immune and glial cells. It also improves complications observed in type 2 diabetes and has beneficial effects in mouse models of neurodegenerative disease. Benfotiamine represents an off-the-shelf agent used to support nerve health, promote healthy aging and support glucose metabolism. Accordingly, the present review aimed to provide an overview of the neuroprotective effects of thiamine/benfotiamine in the context of inflammation and oxidative stress.

Bacterial lipopolysaccharide inhibits colonic carrier-mediated uptake of thiamin pyrophosphate: roles for TLR4 receptor and NF-κB/P38/JNK signaling pathway

This study investigated the effect of the bacterial endotoxin lipopolysaccharide (LPS) on colonic uptake of thiamin pyrophosphate (TPP), the biologically active form of vitamin B1 that is generated by gut microbiota. We used three complementary models in our study: in vitro (human-derived colonic epithelial NCM460), ex vivo (human differentiated colonoid monolayers), and in vivo (mouse colonic tissue). The results showed that exposure of NCM460 cells to LPS leads to a significant inhibition of carrier-mediated TPP uptake as well as in decreased expression of the colonic TPP transporter (cTPPT) protein, mRNA, and heterologous nuclear RNA (hnRNA) compared with untreated controls. Similarly, exposure of human differentiated colonoid monolayers and mice to LPS caused significant inhibition in colonic carrier-mediated TPP uptake and in cTPPT protein, mRNA, and hnRNA expression. The effect of LPS on colonic TPP uptake and cTTPT expression was also found to be associated with a significant reduction in activity of the SLC44A4 promoter as well as in decreased expression of the nuclear factor Elf-3 (E74-like ETS transcription factor 3), which is needed for promoter activity. Finally, we found that knocking down the Toll-like receptor 4 (TLR4) and blocking the nuclear factor kappa B (NF-κB), JNK, and p38 signaling pathways with the use of pharmacological inhibitors lead to significant abrogation in the degree of LPS-mediated inhibition in TPP uptake and cTPPT expression. These results demonstrated that exposure of colonic epithelia to LPS inhibits colonic TPP uptake via transcriptional mechanism(s) and that the effect is mediated via TLR4 receptor and NF-κB/p38/JNK signaling pathways.NEW & NOTEWORTHY This study examined the effect of the bacterial lipopolysaccharide (LPS) on the colonic uptake of thiamin pyrophosphate (TPP), the biologically active form of vitamin B1. Three complementary models were used: in vitro (human NCM460 cells), ex vivo (human colonoids), and in vivo (mice). The results showed LPS to significantly suppress TPP uptake and the expression of its transporter, and that these effects are mediated via the membrane TLR4 receptor, and involve the NF-κB/p38/JNK signaling pathways.

How Can Insulin Resistance Cause Alzheimer's Disease?

Alzheimer's disease (AD) is a neurodegenerative disorder associated with cognitive decline. Despite worldwide efforts to find a cure, no proper treatment has been developed yet, and the only effective countermeasure is to prevent the disease progression by early diagnosis. The reason why new drug candidates fail to show therapeutic effects in clinical studies may be due to misunderstanding the cause of AD. Regarding the cause of AD, the most widely known is the amyloid cascade hypothesis, in which the deposition of amyloid beta and hyperphosphorylated tau is the cause. However, many new hypotheses were suggested. Among them, based on preclinical and clinical evidence supporting a connection between AD and diabetes, insulin resistance has been pointed out as an important factor in the development of AD. Therefore, by reviewing the pathophysiological background of brain metabolic insufficiency and insulin insufficiency leading to AD pathology, we will discuss how can insulin resistance cause AD.

Tumor necrosis factor α impedes colonic thiamin pyrophosphate and free thiamin uptake: involvement of JNK/ERK1/2-mediated pathways

The aim of this study was to examine the effect of TNFα (i.e., a predominant proinflammatory cytokine produced during chronic gut inflammation) on colonic uptake of thiamin pyrophosphate (TPP) and free thiamin, forms of vitamin B1 that are produced by the gut microbiota and are absorbed via distinct carrier-mediated systems. We utilized human-derived colonic epithelial CCD841 and NCM460 cells, human differentiated colonoid monolayers, and mouse intact colonic tissue preparations together with an array of cellular/molecular approaches in our investigation. The results showed that exposure of colonic epithelial cells to TNFα leads to a significant inhibition in TPP and free thiamin uptake. This inhibition was associated with: 1) a significant suppression in the level of expression of the colonic TPP transporter (cTPPT; encoded by SLC44A4), as well as thiamin transporters-1 & 2 (THTR-1 & -2; encoded by SLC19A2 & SLC19A3, respectively); 2) marked inhibition in activity of the SLC44A4, SLC19A2, and SLC19A3 promoters; and 3) significant suppression in level of expression of nuclear factors that are needed for activity of these promoters (i.e., CREB-1, Elf-3, NF-1A, SP-1). Furthermore, the inhibitory effects were found to be mediated via JNK and ERK1/2 signaling pathways. We also examined the level of expression of cTPPT and THTR-1 & -2 in colonic tissues of patients with active ulcerative colitis and found the levels to be significantly lower than in healthy controls. These findings demonstrate that exposure of colonocytes to TNFα suppresses TPP and free thiamin uptake at the transcriptional level via JNK- and Erk1/2-mediated pathways.

Neuroinflammation regulates the balance between hippocampal neuron death and neurogenesis in an ex vivo model of thiamine deficiency

Background

Thiamine (vitamin B1) is a cofactor for enzymes of central energy metabolism and its deficiency (TD) impairs oxidative phosphorylation, increases oxidative stress, and activates inflammatory processes that can lead to neurodegeneration. Wernicke–Korsakoff syndrome (WKS) is a consequence of chronic TD, which leads to extensive neuronal death, and is associated with neuropathological disorders, including cognitive deficits and amnesia. The hippocampus is one of the brain areas most affected by WKS. B1 replacement may not be enough to prevent the irreversible cognitive deficit associated with WKS.

Materials and methods

An organotypic hippocampal slice culture (OHC) model was developed to investigate, using immunofluorescence and confocal microscopy and transcriptome analysis, the molecular mechanisms underlying the neurodegeneration associated with TD. The effect of anti-inflammatory pharmacological intervention with resveratrol (RSV) was also assessed in B1-deprived OHCs.

Results

In OHCs cultured without B1, neuronal density decayed after 5 days and, on the 7th day, the epigenetic markings H3K4me3 and H3K9me3 were altered in mature neurons likely favoring gene transcription. Between the 7th and the 14th day, a pulse of neurogenesis was observed followed by a further massive neuron loss. Transcriptome analysis at day nine disclosed 89 differentially expressed genes in response to B1 deprivation. Genes involved in tryptophan metabolism and lysine degradation KEGG pathways, and those with Gene Ontology (GO) annotations related to the organization of the extracellular matrix, cell adhesion, and positive regulation of synaptic transmission were upregulated. Several genes of the TNF and FoxO signaling pathways and with GO terms related to inflammation were inhibited in response to B1 deprivation. Nsd1, whose product methylates histone H3 lysine 36, was upregulated and the epigenetic marking H3K36me3, associated with negative regulation of neurogenesis, was increased in neurons. Treating B1-deprived OHCs with RSV promoted an earlier neurogenesis pulse.

Conclusion

Neuroregeneration occurs in B1-deficient hippocampal tissue during a time window. This phenomenon depends on reducing neuroinflammation and, likely, on metabolic changes, allowing acetyl-CoA synthesis from amino acids to ensure energy supply via oxidative phosphorylation. Thus, neuroinflammation is implicated as a major regulator of hippocampal neurogenesis in TD opening a new search space for treating WKS.

Alzheimer's disease is associated with disruption in thiamin transport physiology: A potential role for neuroinflammation

Alzheimer's disease (AD) is a neurodegenerative disease characterized by Amyloid-β peptide (Aβ) containing plaques and cognitive deficits. The pathophysiology of AD also involves neuroinflammation. Vitamin B1 (thiamin) is indispensable for normal cellular energy metabolism. Thiamin homeostasis is altered in AD, and its deficiency is known to aggravate AD pathology. Little, however, is known about possible alterations in level of expression of thiamin transporters-1 and -2 (THTR-1 and -2) in the brain of AD, and whether pro-inflammatory cytokines affect thiamin uptake by brain cells. We addressed these issues using brain tissue samples [prefrontal cortex (PFC) and hippocampus (HIP)] from AD patients and from 5XFAD mouse model of AD, together with cultured human neuroblastoma SH-SY5Y cells as model. Our results revealed a significantly lower expression of both THTR-1 and THTR-2 in the PFC and HIP of AD patients and 5XFAD mouse model of AD compared to appropriate normal controls. Further, we found that exposure of the SH-SY5Y cells to pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) led to a significant inhibition in thiamin uptake. Focusing on IL-1β, we found the inhibition in thiamin uptake to be time-dependent and reversible; it was also associated with a substantial reduction in expression of THTR-1 (but not THTR-2) protein and mRNA as well as a decrease in promoter activity of the SLC19A2 gene (which encodes THTR-1). Finally, using transcriptomic analysis, we found that thiamin availability in SH-SY5Y cells caused changes in the expression of genes relevant to AD pathways. These studies demonstrate, for the first time, that thiamin transport physiology/molecular biology parameters are negatively impacted in AD brain and that pro-inflammatory cytokines inhibit thiamin uptake by neuroblastoma cells. The results also support a possible role for thiamin in the pathophysiology of AD.

What is the optimum thiamine dose to treat or prevent Wernicke's encephalopathy or Wernicke-Korsakoff syndrome? Results of a randomized controlled trial

Background

The primary cause of Wernicke–Korsakoff syndrome (WKS) is thiamine deficiency, and more than 90% of cases are reported in alcohol‐dependent patients. While observational studies show parenteral thiamine administration drastically reduced WKS‐related mortality, relevant treatment trials have never been conducted to determine the optimum thiamine dose.

Methods

Two double‐blind, parallel groups, randomized controlled trials (RCTs) were conducted to determine the optimal thiamine dose required for (1) the prevention of Wernicke's encephalopathy (WE), the acute phase of WKS, in asymptomatic but “at‐risk” alcohol misuse patients (Study 1) and (2) the treatment of WE in symptomatic alcohol misuse patients (Study 2). Each study had a dosage regimen comprising three parenteral thiamine doses that were allocated at a ratio of 1:1:1. Study 1: Asymptomatic At‐Risk patients (N = 393) received either 100 mg daily, 100 mg thrice daily, or 300 mg thrice daily, for 3 days. Study 2: Symptomatic patients (N = 127) received either 100 mg thrice daily, 300 mg thrice daily, or 500 mg thrice daily, for 5 days. Cognitive function was the primary outcome, assessed using the Rowland Universal Dementia Assessment Scale, two Cogstate subtests, and an adapted Story Memory Recall test. Secondary analyses examined differences in neurological function (ataxia, oculomotor abnormalities, and confusion) at follow‐up.

Results

No significant differences were observed between any of the dosage conditions for either Study 1 or Study 2 on cognition or neurological functioning. This real‐world study found that having a clinically unwell target population with high comorbidity and multiple presentations, coupled with challenges in cross‐cultural assessment is likely to complicate RCT findings.

Conclusions

The results of this study showed no clear benefit of high dose thiamine over intermediate or lower doses of thiamine, over the time intervals examined, for the treatment and prevention of cognitive and neurological abnormalities related to WKS. Several study limitations temper the interpretation of these findings. Nevertheless, the absence of conclusive evidence for the superiority of high‐dose thiamine supports a recommendation for patient‐specific treatment, while ensuring that the potential impact of other biochemical factors (e.g., magnesium and other B vitamin deficiencies) are considered and corrected if necessary.

Thiamine alleviates cognitive impairment and epileptogenesis by relieving brain inflammation in PTZ-induced kindling rat model

OBJECTIVE

Epileptogenesis, the process by which the brain becomes epileptic, is related to neuroinflammation, hyperexcitability cognitive deficits. Evidence suggests that improving brain inflammation can inhibit the epileptogenesis process and help the emergence of new drugs for the treatment of epilepsy. Therefore, the PTZ kindling model of epilepsy was utilized to assess the neuroprotective role of thiamine in epileptogenesis.

METHODS

Male rats were exposed to PTZ-induced kindling and pretreated with low thiamine (25 mg/kg) or high thiamine (50 mg/kg). Cyclooxygenase (COX-1 and COX-2), interleukin 1-beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and nuclear factor-κB (NF-κB) concentrations in the brain were analyzed using biochemical assays. Cognitive function was evaluated using the passive avoidance test.

RESULTS

Thiamine ameliorated epileptogenesis and enhanced the rats' performance in the passive avoidance test. Also, thiamine significantly decreased the level of neuroinflammatory mediators in the brain induced by PTZ.

CONCLUSION

These results provide evidence that thiamine alleviates PTZ-induced neuroinflammation and cognitive impairments.

Hypoxia inhibits colonic uptake of the microbiota-generated forms of vitamin B1 via HIF-1α-mediated transcriptional regulation of their transporters

Hypoxia exerts profound effects on cell physiology, but its effect on colonic uptake of the microbiota-generated forms of vitamin B1 (i.e., thiamin pyrophosphate [TPP] and free thiamine) has not been described. Here, we used human colonic epithelial NCM460 cells and human differentiated colonoid monolayers as in vitro and ex vivo models, respectively, and were subjected to either chamber (1% O2, 5% CO2, and 94% N2) or chemically (desferrioxamine; 250 μM)-induced hypoxia followed by determination of different physiological-molecular parameters. We showed that hypoxia causes significant inhibition in TPP and free thiamin uptake by colonic NCM460 cells and colonoid monolayers; it also caused a significant reduction in the expression of TPP (SLC44A4) and free thiamin (SLC19A2 and SLC19A3) transporters and in activity of their gene promoters. Furthermore, hypoxia caused a significant induction in levels of hypoxia-inducible transcription factor (HIF)-1α but not HIF-2α. Knocking down HIF-1α using gene-specific siRNAs in NCM460 cells maintained under hypoxic conditions, on the other hand, led to a significant reversal in the inhibitory effect of hypoxia on TPP and free thiamin uptake as well as on the expression of their transporters. Finally, a marked reduction in level of expression of the nuclear factors cAMP responsive element-binding protein 1 and gut-enriched Krüppel-like factor 4 (required for activity of SLC44A4 and SLC19A2 promoters, respectively) was observed under hypoxic conditions. In summary, hypoxia causes severe inhibition in colonic TPP and free thiamin uptake that is mediated at least in part via HIF-1α-mediated transcriptional mechanisms affecting their respective transporters.

Thiamine supplementation in hospitalized patients with altered mental status: does it help?

OBJECTIVE

To describe thiamine-prescribing patterns and to study the association of thiamine supplementation with clinical outcomes in hospitalized patients with altered mental status (AMS).

METHODS

We conducted a retrospective cohort study of all adult hospitalized patients with AMS with index admission in calendar year 2017. We studied the association of a) supplemental thiamine and b) timing of thiamine relative to glucose, with hospital outcomes - length of stay (LOS), 90-day readmission rates, and mortality rates - using linear, logistic, and extended Cox models, respectively. We also modeled association of supplemental thiamine on time to resolution of AMS using extended Cox models in patients admitted with AMS.

RESULTS

Of 985 patients, 178 (18%) received thiamine, including 123 (12.5%) who received thiamine before, with, or without glucose (thiamine first). We identified 365 (37%) patients who received intravenous glucose before or without thiamine (glucose first). We found that patients who received glucose first had longer LOS and higher rate of in-hospital deaths compared to those who did not. Patients who received thiamine supplementation had longer LOS compared to those who did not. There were no significant differences in other hospital outcomes or AMS resolution by discharge compared to their respective reference groups.

CONCLUSION

Although thiamine supplementation was not associated with better hospital or cognitive outcomes, we do not have enough evidence to suggest a change in current practice. Thiamine must be administered prior to glucose in hospitalized patients with AMS.

Protocol for thiamine and folic acid in the treatment of cognitive impairment in maintenance haemodialysis patients: a prospective, randomised, placebo-controlled, double-blind, multicentre study

INTRODUCTION

Cognitive impairment (CI) is the common complications in maintenance haemodialysis (MHD) patients. Recently, the pathogenesis of CI has been discussed and oxidative stress is one of the main mechanisms in these patients. Thiamine and folic acid, which play an important role in relieving the production of reactive oxygen species, reducing homocysteine levels, improving oxidative stress in the nervous system. In pilot study, cognitive function was significantly improved in the group with thiamine and folic supplementation. Based on this result, we hypothesise that thiamine combined with folic acid supplementation may improve cognitive function in patients with MHD.

METHODS AND ANALYSIS

In this prospective, randomised, placebo-controlled, double-blind, multicentre study, we will enrol patients undergoing haemodialysis who has the Montreal Cognitive Assessment score lower than 26 to treatment group (thiamine 90 mg/day combined with folic acid 30 mg/day) or control group (thiamine placebo 90 mg/day combined with folic acid placebo 30 mg/day). All subjects will be followed up for 96 weeks. The primary endpoint is the comparison of Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) score between treatment group and control group at 96 weeks of follow-up. The secondary endpoints include serum thiamine, folate, homocysteine levels, cranial functional MRI and survival. The central randomisation method will be adopted and the principles of placebo-controlled, double-blind randomised control will be followed. The comparisons among ADAS-Cog scores and other secondary endpoints over time within subjects is conducted by using repeated measure analysis of variance (ANOVA) or generalised estimating equations (GEE). Pairwise t-test with Bonferroni adjustment is performed for multiple comparisons. On the other hand, for comparisons between treatment and control group, simple one-way ANOVA, GEE or Wilcoxon rank sum test is used. The χ² method is used for statistical analysis of the categorical data. Kaplan-Meier survival curve is used for survival analysis. A p<0.05 is considered statistically significant difference.

ETHICS AND DISSEMINATION

This trial has been approved by Shanghai Jiao Tong University School of Medicine, Renji Hospital Ethics Committee (KY2019-199). After publication of study results, trial report will be published in peer-reviewed journals and/or in national or international conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2000029297.

Thiamine modulates intestinal morphological structure and microbiota under subacute ruminal acidosis induced by a high-concentrate diet in Saanen goats

Ruminant animals are generally fed with starch-rich grain as the main energy source, and the incidence of metabolic diseases such as subacute ruminal acidosis (SARA) is high due to the intensive farming. Thiamin has been reported to alleviate SARA caused by high-concentrate diets, but the exact mechanism is not well understood. The goal of this study was to examine the role of thiamine in intestinal inflammation and microbiota caused by high-concentrate diets. The SARA model was induced by low neutral detergent fibre/starch ration to study the effects of thiamine on intestinal tissue structure and microbiota. 18 mid-lactation (148 ± 3 d in milk; milk yield = 0.71 ± 0.0300 kg/d) Saanen goats (BW = 36.5 ± 1.99 kg; body condition score = 2.73 ± 0.16, where 1 = emaciated and 6 = obese) in parities 1 or 2 were selected. The goats were randomly divided into three groups with six replicates: (1) control diet (C; concentrate:forage 30:70), (2) high-concentrate diet (H; concentrate:forage 70:30), and (3) high-concentrate diet with 200 mg of thiamine/kg of DM intake (H + T;concentrate:forage 70:30). The experimental period was lasted for 56 d. The small and large intestine, expression of inflammatory factor genes, tight junction protein genes, total antioxidant capacity, and intestinal microbiota were measured. The results showed that SARA was observed in treatment H, whereas rumen fluid pH was improved in treatment H + T. Treatment H + T also significantly repaired the intestinal tissue structure damaged by SARA, improved the total antioxidant capacity of the small intestinal mucosa, reduced mRNA expression of inflammatory factors in the small intestine tissue, and increased the mRNA expression of tight junction genes in small intestine tissue. The high-concentrate diet reduced the diversity of intestinal microbiota. When thiamine is added to the high-concentrate diet, the relative abundance of intestinal Firmicutes and beneficial bacteria represented by Lactobacilli were upregulated, and the relative abundance of Proteus, a marker of intestinal dysbacteriosis, returned to normal. In conclusion, thiamine supplementation could alleviate the damage to the intestinal tissue structure and microbial environment caused by SARA condition in dairy goats fed a high-concentrate diet.

Gut microbiome in people living with HIV is associated with impaired thiamine and folate syntheses

People living with HIV have a high incidence of cardiovascular and neurological diseases as comorbid disorders that are commonly linked to inflammation. While microbial translocation can augment inflammation during HIV infection, functional microbiome shifts that may increase pro-inflammatory responses have not been fully characterized. In addition, defining HIV-induced microbiome changes has been complicated by high variability among individuals. Here we conducted functional annotation of previously-published 16S ribosomal RNA gene sequences of 305 HIV positive and 249 negative individuals, with adjustment for geographic region, sex, sexual behavior, and age. Metagenome profiles were inferred from these individuals' 16S data. HIV infection was associated with impaired microbial vitamin B synthesis; around half of the gene families in thiamine and folate biosynthesis pathways were significantly less abundant in the HIV positive group than the negative control. These results are consistent with the high prevalence of thiamine and folate deficiencies in HIV infections. These HIV-induced microbiota shifts have the potential to influence cardiovascular and neurocognitive diseases, given the documented associations between B-vitamin deficiencies, inflammation, and these diseases. We also observed that most essential amino acid biosynthesis pathways were downregulated in the microbiome of HIV-infected individuals. Microbial vitamin B and amino acid synthesis pathways were not significantly recovered by antiretroviral treatment when we compared 262 ART positive and 184 ART negative individuals. Our meta-analysis provides a new outlook for understanding vitamin B and amino acid deficiencies in HIV patients, suggesting that interventions for reversing HIV-induced microbiome shifts may aid in lessening the burdens of HIV comorbidities.

Thiamine deficiency and recovery: impact of recurrent episodes and beneficial effect of treatment with Trolox and dimethyl sulfoxide

At present, thiamine deficiency (TD) is managed with administration of high doses of thiamine. Even so, severe and permanent neurological disorders can occur in recurrent episodes of TD. In this study, we used a murine model to assess the efficacy of TD recovery treatments using thiamine with or without additional administration of the antioxidant Trolox or the anti-inflammatory dimethyl sulfoxide (DMSO) after a single or recurrent episode of TD. TD was induced for 9 days with deficient chow and pyrithiamine, and the recovery period was 7 days with standard amounts of chow and thiamine, Trolox, and/or DMSO. After these periods, we evaluated behavior, histopathology, and ERK1/2 modulation in the brain. Deficient animals showed reductions in locomotor activity, motor coordination, and spatial memory. Morphologically, after a single episode of TD and recovery, deficient mice showed neuronal vacuolization in the dorsal thalamus and, after two episodes, a reduction in neuronal cell number. These effects were attenuated or reversed by the recovery treatments, mainly in the treatments with thiamine associated with Trolox or DMSO. Deficient animals showed a strong increase in ERK1/2 phosphorylation in the thalamus, hippocampus, and cerebral cortex after one deficiency episode and recovery. Interestingly, after recurrent TD and recovery, ERK1/2 phosphorylation remained high only in the deficient mice treated with thiamine and/or Trolox or thiamine with DMSO. Our data suggest that a protocol for TD treatment with thiamine in conjunction with Trolox or DMSO enhances the recovery of animals and possibly minimizes the late neurological sequelae.

Midline Thalamic Damage Associated with Alcohol-Use Disorders: Disruption of Distinct Thalamocortical Pathways and Function

The thalamus, a significant part of the diencephalon, is a symmetrical and bilateral central brain structure. The thalamus is subdivided into three major groups of nuclei based on their function: sensorimotor nuclei (or principal/relay nuclei), limbic nuclei and nuclei bridging these two domains. Anatomically, nuclei within the thalamus are described by their location, such as anterior, medial, lateral, ventral, and posterior. In this review, we summarize the role of medial and midline thalamus in cognition, ranging from learning and memory to flexible adaptation. We focus on the discoveries in animal models of alcohol-related brain damage, which identify the loss of neurons in the medial and midline thalamus as drivers of cognitive dysfunction associated with alcohol use disorders. Models of developmental ethanol exposure and models of adult alcohol-related brain damage and are compared and contrasted, and it was revealed that there are similar (anterior thalamus) and different (intralaminar [adult exposure] versus ventral midline [developmental exposure]) thalamic pathology, as well as disruptions of thalamo-hippocampal and thalamo-cortical circuits. The final part of the review summarizes approaches to recover alcohol-related brain damage and cognitive and behavioral outcomes. These approaches include pharmacological, nutritional and behavioral interventions that demonstrated the potential to mitigate alcohol-related damage. In summary, the medial/midline thalamus is a significant contributor to cognition function, which is also sensitive to alcohol-related brain damage across the life span, and plays a role in alcohol-related cognitive dysfunction.

Delirium in Critical Illness Patients and the Potential Role of Thiamine Therapy in Prevention and Treatment: Findings from a Scoping Review with Implications for Evidence-Based Practice

INTRODUCTION

Thiamine is a water-soluble vitamin and is necessary for energy metabolism. Critically ill patients are at particular risk of developing thiamine deficiency and related complications. One of the complications that can occur is delirium. Delirium is a disorder that affects the body's response to treatment, length of stay in the ward, mortality, long-term cognitive impairment, and significantly increases treatment costs. In addition, studies show that delirium medication is more effective in preventing than in treating delirium. Given its low cost, availability, and minimal risk of side effects, thiamine supplementation could prove to be a relevant strategy in the prevention and treatment of delirium.

METHODS

PubMed, Cochrane Library, Ovid, and ClinicalTrials.gov databases were searched using relevant keywords that focus on the use of thiamine to prevent or treat delirium in critically ill patients.

RESULTS

Seven articles were included in the analysis.

CONCLUSION

The small number of studies and considerable heterogeneity prevent conclusions supporting the use of thiamine as an adjuvant in the prevention and treatment of delirium among critically ill patients. There is a need for high-quality, large-scale randomized clinical trials to confirm the beneficial effects of thiamine in the prevention and treatment of delirium.

Potential protective effects of thiamine supplementation on the ruminal epithelium damage during subacute ruminal acidosis

In ruminants, the ruminal epithelium not only has the function of absorbing nutrients but also is an important tissue to prevent harmful substances in the rumen from entering the blood circulation. Thus, the normal function of ruminal epithelium is critical for ruminants. However, subacute ruminal acidosis induced by high-concentrate diets often damages the barrier function of ruminal epithelium in ruminants. Recently, many studies have shown that dietary supplementation with thiamine is an effective method to alleviate subacute ruminal acidosis. In order to provide theoretical reference for the in-depth study of subacute ruminal acidosis and the application of thiamine in the future, this review introduces the effects of subacute ruminal acidosis on morphological structure, inflammatory response, and tight junction of ruminal epithelium. In addition, this paper summarizes the role of thiamine in maintaining ruminal epithelial function of ruminants during subacute ruminal acidosis challenge.

Cerebellar and cortical TLR4 activation and behavioral impairments in Wernicke-Korsakoff Syndrome: Pharmacological effects of oleoylethanolamide

Wernicke-Korsakoff Syndrome (WKS) is a neuropsychiatric disorder whose etiology is a thiamine deficiency (TD), with alcoholism being the main underlying cause. Previous evidence suggests the presence of initial neuroinflammation and oxidative/nitrosative stress in the physiopathology, although the specific molecular mechanisms underlying TD-induced brain damage and behavioral disabilities are unknown. We explored the specific role of the innate immune receptor TLR4 in three murine models of WKS, based on the combination of a thiamine-deficient diet and pyrithiamine injections (0.25 mg/kg, i.p.) over time. The Symptomatic Model (SM) allowed us to describe the complete neurological/neurobehavioral symptomatology over 16 days of TD. Animals showed an upregulation of the TLR4 signaling pathway both in the frontal cortex (FC) and cerebellum and clear motor impairments related with cerebellar dysfunction. However, in the Pre-Symptomatic Model (PSM), 12 days of TD induced the TLR4 pathway upregulation in the FC, which correlated with disinhibited-like behavior, but not in the cerebellum, and no motor impairments. In addition, we tested the effects of the biolipid oleoylethanolamide (OEA, 10 mg/kg, i.p., once daily, starting before any symptom of the pathology is manifested) through the Glucose-Precipitated Model (GPM), which was generated by glucose loading (5 g/kg, i.v., last day) in thiamine-deficient animals to accelerate damage. Pretreatment with OEA prevented the TLR4-induced signature in the FC, as well as an underlying incipient memory disability and disinhibited-like behavior. This study suggests a key role for TLR4 in TD-induced neuroinflammation in the FC and cerebellum, and it reveals different vulnerability of these brain regions in WKS over time. Pre-treatment with OEA counteracts TD-induced TLR4-associated neuroinflammation and may serve as co-adjuvant therapy to prevent WKS-induced neurobehavioral alterations.

Neuroprotective Effects of Thiamine and Precursors with Higher Bioavailability: Focus on Benfotiamine and Dibenzoylthiamine

Thiamine (vitamin B1) is essential for brain function because of the coenzyme role of thiamine diphosphate (ThDP) in glucose and energy metabolism. In order to compensate thiamine deficiency, several thiamine precursors with higher bioavailability were developed since the 1950s. Among these, the thioester benfotiamine (BFT) has been extensively studied and has beneficial effects both in rodent models of neurodegeneration and in human clinical studies. BFT has antioxidant and anti-inflammatory properties that seem to be mediated by a mechanism independent of the coenzyme function of ThDP. BFT has no adverse effects and improves cognitive outcome in patients with mild Alzheimer’s disease (AD). Recent in vitro studies show that another thiamine thioester, dibenzoylthiamine (DBT) is even more efficient that BFT, especially with respect to its anti-inflammatory potency. Thiamine thioesters have pleiotropic properties linked to an increase in circulating thiamine concentrations and possibly in hitherto unidentified metabolites in particular open thiazole ring derivatives. The identification of the active neuroprotective derivatives and the clarification of their mechanism of action open extremely promising perspectives in the field of neurodegenerative, neurodevelopmental and psychiatric conditions.

Developmental maturation of the colonic uptake process of the microbiota-generated thiamin pyrophosphate

The water-soluble vitamin B1 is essential for normal human health and physiology. In its main biologically active form, i.e., thiamin pyrophosphate (TPP), the vitamin plays many critical roles in cell metabolism; thus, its deficiency leads to a variety of adverse effects. Humans/mammals obtain vitamin B1 from two exogenous sources: diet and gut microbiota. Considerable amount of the microbiota-generated vitamin B1 exists in the form of TPP, and colonocytes can efficiently absorb this TPP via a high-affinity and specific carrier-mediated mechanism that involves the recently cloned colonic TPP transporter (cTPPT; product of SLC44A4 gene). There is nothing currently known about colonic uptake of TPP during early stages of life and whether the process undergoes developmental regulation. We addressed this issue using the mouse as animal model. Our results showed that colonic uptake of TPP undergoes developmental upregulation as the animal moves from the suckling period to weanling and adulthood. This upregulation in uptake was found to be associated with a parallel induction in level of expression of the cTPPT protein, mRNA, and heterogeneous nuclear RNA, suggesting possible involvement of transcriptional mechanism(s). We also found a parallel upregulation in the level of expression of the two nuclear factors that drive activity of the SLC44A4 promoter (i.e., CREB-1 and Elf-3) with maturation. These results demonstrate, for the first time, to our knowledge, that colonic TPP uptake process and cTPPT expression are developmentally upregulated and that this upregulation is likely driven via transcriptional mechanism(s).NEW & NOTEWORTHY The colonic carrier-mediated uptake process of the microbiota-generated and phosphorylated form of vitamin B1, i.e., thiamin pyrophosphate, undergoes ontogenic changes that parallel the development of the gut microbiota (and their ability to generate vitamins) during early stages of life.

Memantine Usage for Management of Korsakoff Syndrome in the Setting of Chronic Alcohol Use and Unspecified Eating Disorder

Korsakoff syndrome is a neuropsychiatric condition frequently seen as a progression of Wernicke’s encephalopathy and is often associated with long-term alcohol abuse. It is characterized by further cognitive impairments, such as indiscriminate anterograde and retrograde amnesia, in addition to executive function deficits. As the syndrome is a result of severe thiamine deficiency, its management primarily focuses on nutritional replenishment and electrolyte maintenance. In recent years, a few published reports have detailed the off-label use of Food and Drug Administration (FDA) approved drugs for Alzheimer’s in an attempt to treat neurocognitive deficits associated with Korsakoff patients. In this particular case, we note subjective improvement in cognition after initiating memantine, an N-Methyl-d-aspartate (NMDA) receptor antagonist.

[Refeeding syndrome]

Refeeding syndrome (RS) is a rare but severe condition that is poorly understood, often under-diagnosed and can lead to death. It occurs within 5 days after refeeding in patients after prolonged fasting or in a context of undernutrition. As a consequence of the abrupt transition from catabolism to anabolism, RS is defined as a decrease in plasma levels of phosphorus, potassium and/or magnesium, whether or not associated with organ dysfunction resulting from a decrease in one of the electrolytes or a thiamine deficiency, after refeeding. The clinical symptoms are varied and non-specific and are related to hydro electrolyte disorders, sodium-hydroxide retention or failure of one or more organs. Patient management should be appropriate with regular clinical examination and careful biological monitoring, including hydro electrolyte monitoring. The correction of hydroelectrolytic disorders and systematic thiamine supplementation are essential during refeeding, that must be done carefully and very progressively, whatever its form (oral, enteral or parenteral). The severity of the refeeding syndrome indicates that its prevention and screening are the corners of its management in at-risk patients.

Wernicke's encephalopathy - from basic science to clinical practice. Part 1: Understanding the role of thiamine

Wernicke's encephalopathy (WE) is an acute neuropsychiatric state. Untreated, WE can lead to coma or death, or progress to Korsakoff syndrome (KS) - a dementia characterized by irreversible loss of anterograde memory. Thiamine (vitamin B1) deficiency lies at the heart of this condition. Yet, our understanding of thiamine regarding prophylaxis and treatment of WE remains limited. This may contribute to the current undertreatment of WE in clinical practice. The overall aim of this review is to identify the best strategies for prophylaxis and treatment of WE in regard to (a) dose of thiamine, (b) mode of administration, (c) timing of switch from one mode of administration to another, (d) duration of administration, and (e) use of magnesium along thiamine as an essential cofactor. Evidence from randomized controlled trials and other intervention studies is virtually absent. Therefore, we have to resort to basic science for proof of principle instead. Here, we present the first part of our clinical review, in which we explore the physiology of thiamine and the pathophysiology of thiamine deficiency. We first explore both of these in their historical context. We then review the pharmacodynamics and pharmacokinetics of thiamine, exploring the roles of the six currently known thiamine compounds, their transporters, and target enzymes. We also explore the significance of magnesium as a cofactor in thiamine-facilitated enzymatic reactions and thiamine transport. In the second (forthcoming) part of this review, we will use the findings of the current review to make evidence-based inferences about strategies for prophylaxis and treatment of WE.

The Inferior Colliculus in Alcoholism and Beyond

Post-mortem neuropathological and in vivo neuroimaging methods have demonstrated the vulnerability of the inferior colliculus to the sequelae of thiamine deficiency as occurs in Wernicke-Korsakoff Syndrome (WKS). A rich literature in animal models ranging from mice to monkeys-including our neuroimaging studies in rats-has shown involvement of the inferior colliculi in the neural response to thiamine depletion, frequently accomplished with pyrithiamine, an inhibitor of thiamine metabolism. In uncomplicated alcoholism (i.e., absent diagnosable neurological concomitants), the literature citing involvement of the inferior colliculus is scarce, has nearly all been accomplished in preclinical models, and is predominately discussed in the context of ethanol withdrawal. Our recent work using novel, voxel-based analysis of structural Magnetic Resonance Imaging (MRI) has demonstrated significant, persistent shrinkage of the inferior colliculus using acute and chronic ethanol exposure paradigms in two strains of rats. We speculate that these consistent findings should be considered from the perspective of the inferior colliculi having a relatively high CNS metabolic rate. As such, they are especially vulnerable to hypoxic injury and may be provide a common anatomical link among a variety of disparate insults. An argument will be made that the inferior colliculi have functions, possibly related to auditory gating, necessary for awareness of the external environment. Multimodal imaging including diffusion methods to provide more accurate in vivo visualization and quantification of the inferior colliculi may clarify the roles of brain stem nuclei such as the inferior colliculi in alcoholism and other neuropathologies marked by altered metabolism.

Thiamine Deficiency Increases Intrinsic Excitability of Mouse Cerebellar Purkinje Cells

Thiamine deficiency is associated with cerebellar dysfunction; however, the consequences of thiamine deficiency on the electrophysiological properties of cerebellar Purkinje cells are poorly understood. Here, we evaluated these parameters in brain slices containing cerebellar vermis. Adult mice were maintained for 12-13 days on a thiamine-free diet coupled with daily injections of pyrithiamine, an inhibitor of thiamine phosphorylation. Morphological analysis revealed a 20% reduction in Purkinje cell and nuclear volume in thiamine-deficient animals compared to feeding-matched controls, with no reduction in cell count. Under whole-cell current clamp, thiamine-deficient Purkinje cells required significantly less current injection to fire an action potential. This reduction in rheobase was not due to a change in voltage threshold. Rather, thiamine-deficient neurons presented significantly higher input resistance specifically in the voltage range just below threshold, which increases their sensitivity to current at these critical membrane potentials. In addition, thiamine deficiency caused a significant decrease in the amplitude of the action potential afterhyperpolarization, broadened the action potential, and decreased the current threshold for depolarization block. When thiamine-deficient animals were allowed to recover for 1 week on a normal diet, rheobase, threshold, action potential half-width, and depolarization block threshold were no longer different from controls. We conclude that thiamine deficiency causes significant but reversible changes to the electrophysiology properties of Purkinje cells prior to pathological morphological alterations or cell loss. Thus, the data obtained in the present study indicate that increased excitability of Purkinje cells may represent a leading indicator of cerebellar dysfunction caused by lack of thiamine.

Posttranscriptional regulation of thiamin transporter-1 expression by microRNA-200a-3p in pancreatic acinar cells

The water-soluble vitamin B1 (thiamin) plays essential roles in normal metabolism and function of all human/mammalian cells, including the pancreatic acinar cells (PACs). PACs obtain thiamin from their surrounding circulation via transport across the plasma membrane, a process that is mediated by thiamin transporter (THTR)-1 and THTR-2. We have previously characterized different aspects of thiamin uptake by mouse and human primary PACs, but little is known about posttranscriptional regulation of the uptake event. We addressed this by focusing on the predominant thiamin transporter THTR-1 (encoded by SLC19A2 gene) in PACs. Transfecting pmirGLO-SLC19A2 3'-untranslated region (UTR) into mouse-derived PAC 266-6 cells leads to a significant reduction in luciferase activity compared with cells transfected with empty vector. Subjecting the SLC19A2 3'-UTR to different in silico algorithms identified multiple putative microRNA binding sites in this region. Focusing on miR-200a-3p (since it is highly expressed in mouse and human pancreas), we found that transfecting PAC 266-6 and human primary PACs (hPACs) with mimic miR-200a-3p leads to a significant inhibition of THTR-1 expression (both protein and mRNA levels) and in thiamin uptake. In contrast, transfection by miR-200a-3p inhibitor leads to an increase in THTR-1 expression and thiamin uptake. Additionally, truncating the region carrying miR-200a-3p binding site in SLC19A2 3'-UTR and mutating the binding site lead to abrogation in the inhibitory effect of this microRNA on luciferase activity in PAC 266-6. These results demonstrate that expression of THTR-1 and thiamin uptake in PACs is subject to posttranscriptional regulation by microRNAs.NEW & NOTEWORTHY The findings of this study show, for the first time, that the membrane transporter of vitamin B1, i.e., thiamin transporter-1 (THTR-1), is subject to regulation by microRNAs (specifically miR-200a-3p) in mouse and human primary pancreatic acinar cells (PACs). The results also show that this posttranscriptional regulation has functional consequences on the ability of PACs to take in the essential micronutrient thiamin.

Thiamine Deficiency Modulates p38MAPK and Heme Oxygenase-1 in Mouse Brain: Association with Early Tissue and Behavioral Changes

Thiamine deficiency (TD) produces severe neurodegenerative lesions. Studies have suggested that primary neurodegenerative events are associated with both oxidative stress and inflammation. Very little is known about the downstream effects on intracellular signaling pathways involved in neuronal death. The primary aim of this work was to evaluate the modulation of p38^MAPK and the expression of heme oxygenase 1 (HO-1) in the central nervous system (CNS). Behavioral, metabolic, and morphological parameters were assessed. Mice were separated into six groups: control (Cont), TD with pyrithiamine (Ptd), TD with pyrithiamine and Trolox (Ptd + Tr), TD with pyrithiamine and dimethyl sulfoxide (Ptd + Dmso), Trolox (Tr) and DMSO (Dmso) control groups and treated for 9 days. Control groups received standard feed (AIN-93M), while TD groups received thiamine deficient feed (AIN-93DT). All the groups were subjected to behavioral tests, and CNS samples were collected for cell viability, histopathology and western blot analyses. The Ptd group showed a reduction in weight gain and feed intake, as well as a reduction in locomotor, grooming, and motor coordination activities. Also, Ptd group showed a robust increase in p38^MAPK phosphorylation and mild HO-1 expression in the cerebral cortex and thalamus. The Ptd group showed a decreased cell viability, hemorrhage, spongiosis, and astrocytic swelling in the thalamus. Groups treated with Trolox and DMSO displayed diminished p38^MAPK phosphorylation in both the structures, as well as attenuated thalamic lesions and behavioral activities. These data suggest that p38^MAPK and HO-1 are involved in the TD-induced neurodegeneration in vivo, possibly modulated by oxidative stress and neuroinflammation.

Thiamine ameliorates inflammation of the ruminal epithelium of Saanen goats suffering from subacute ruminal acidosis

This study aimed to examine the role of thiamine in the local inflammation of ruminal epithelium caused by high-concentrate diets. Eighteen mid-lactating (148 ± 3 d in milk; milk yield = 0.71 ± 0.0300 kg/d) Saanen goats (body weight = 36.5 ± 1.99 kg; body condition score = 2.73 ± 0.16, where 0 = emaciated and 5 = obese) in parity 1 or 2 were selected. The goats were randomly divided into 3 groups (n = 6/group): (1) control diet (concentrate:forage 30:70), (2) high-concentrate diet (HC; concentrate:forage 70:30), and (3) high-concentrate diet with 200 mg of thiamine/kg of dry matter intake (THC; concentrate:forage 70:30). Goats remained on experimental diets for 8 wk. On the last day of 8 wk, ruminal and blood samples were collected to determine ruminal parameters, endotoxin lipopolysaccharide, and blood inflammatory cytokines. Goats were slaughtered to collect ruminal tissue to determine gene and protein expression of toll-like receptor 4 (TLR4) signaling pathways. Thiamine supplementation increased ruminal pH (6.03 vs. 5.42) compared with the HC group. Propionate (21.08 vs. 31.61 mM), butyrate (12.08 vs. 19.39 mM), lactate (0.52 vs. 0.71 mM), and free lipopolysaccharide (42.16 vs. 55.87 × 10³ endotoxin units/mL) concentrations in ruminal fluid were lower in THC goats compared with HC goats. Similar to plasma interleukin 1β (IL-1β) concentration (209.31 vs. 257.23 pg/mL), blood CD8⁺ percentage (27.57 vs. 34.07%) also decreased in response to thiamine. Compared with HC goats, THC goats had lower ruminal epithelium activity of the enzymes myeloperoxidase and matrix metalloproteinase (MMP) 2 and 9. In contrast to HC, THC had downregulated mRNA expression of nuclear factor-κB (NFKB), TLR4, IL1B, MMP2, and MMP9 in ruminal epithelium. Thiamine supplementation led to lower relative protein expression of IL-1β, NF-κB unit p65, and phosphorylated NF-κB unit p65 in ruminal epithelium. Taken together, these results suggest that thiamine supplementation mitigates HC-induced local inflammation and ruminal epithelial disruption.

Alteration in MDA, GSH level and hematological changes due to thiamine deficiency in Mus musculus

It is known that thiamine deficiency may lead to Alzheimer’s diseases in humans. The present study has thus been conducted to understand the role of thiamine deficiency with respect to alteration in the peripheral blood of Swiss albino mice. For this purpose, adult Swiss albino mice (6–8 week old) were divided into three groups. The first group was control; the second (group II) and the third group (group III) were made thiamine deficient for 08 and 10 days respectively. Thiamine deficiency was induced in mice by injecting pyrithiamine (5 µg/10 g bwt) and feeding a thiamine deficient diet. The erythrocytes, leukocytes count, hemoglobin, hematocrit value, mass cell volume, mean corpuscular hemoglobin in blood of mice were determined by hematoanalyzer. Malondialdehyde (MDA) and reduced glutathione (GSH) level was also determined in serum of treated and non-treated groups. A significant reduction in leukocyte and erythrocyte count was observed in both the thiamine deficient groups as compared to control. Levels of hemoglobin and hematocrit value were also declined in the thiamine deficient groups. Enhancement in mass cell volume (MCV) level and decline in mean corpuscular hemoglobin (MCH) levels were observed in both thiamine deficient groups with respect to control. Inter-group comparison of all parameters also showed a significant value at p<0.01. In comparison with the control group, elevation in MDA and decline in GSH level was observed in both thiamine deficient groups which were statistically significant. These data indicate that thiamine deficiency leads to significant alterations in the hematological parameters as well as in MDA and GSH level.

Aging with alcohol-related brain damage: Critical brain circuits associated with cognitive dysfunction

Alcoholism is associated with brain damage and impaired cognitive functioning. The relative contributions of different etiological factors, such as alcohol, thiamine deficiency and age vulnerability, to the development of alcohol-related neuropathology and cognitive impairment are still poorly understood. One reason for this quandary is that both alcohol toxicity and thiamine deficiency produce brain damage and cognitive problems that can be modulated by age at exposure, aging following alcohol toxicity or thiamine deficiency, and aging during chronic alcohol exposure. Pre-clinical models of alcohol-related brain damage (ARBD) have elucidated some of the contributions of ethanol toxicity and thiamine deficiency to neuroinflammation, neuronal loss and functional deficits. However, the critical variable of age at the time of exposure or long-term aging with ARBD has been relatively ignored. Acute thiamine deficiency created a massive increase in neuroimmune genes and proteins within the thalamus and significant increases within the hippocampus and frontal cortex. Chronic ethanol treatment throughout adulthood produced very minor fluctuations in neuroimmune genes, regardless of brain region. Intermittent "binge-type" ethanol during the adolescent period established an intermediate neuroinflammatory response in the hippocampus and frontal cortex, that can persist into adulthood. Chronic excessive drinking throughout adulthood, adolescent intermittent ethanol exposure, and thiamine deficiency all led to a loss of the cholinergic neuronal phenotype within the basal forebrain, reduced hippocampal neurogenesis, and alterations in the frontal cortex. Only thiamine deficiency results in gross pathological lesions of the thalamus. The behavioral impairment following these types of treatments is hierarchical: Thiamine deficiency produces the greatest impairment of hippocampal- and prefrontal-dependent behaviors, chronic ethanol drinking ensues mild impairments on both types of tasks and adolescent intermittent ethanol exposure leads to impairments on frontocortical tasks, with sparing on most hippocampal-dependent tasks. However, our preliminary data suggest that as rodents age following adolescent intermittent ethanol exposure, hippocampal functional deficits began to emerge. A necessary requirement for the advancement of understanding the neural consequences of alcoholism is a more comprehensive assessment and understanding of how excessive alcohol drinking at different development periods (adolescence, early adulthood, middle-aged and aged) influences the trajectory of the aging process, including pathological aging and disease.

Thiamine and phosphate esters concentrations in whole blood and serum of patients with alcohol use disorder: a relation with cognitive deficits

Background: In this study, we investigated (1) the effect of chronic and excessive alcohol consumption on whole blood (WB) and serum concentrations of thiamine and its metabolites after supplementation, and (2) the relationship between the perturbations of thiamine metabolism and neuropsychological abilities.Methods: WB and serum samples were collected in patients with Alcohol Use Disorder (AUD) and in healthy control subjects (after oral thiamine supplementation, or without supplementation). Thiamine (Th), thiamine monophosphate (TMP) and thiamine diphosphate (TDP) were quantified. The Brief Evaluation of Alcohol-Related Neuropsychological Impairments (BEARNI) and the Montreal Cognitive Assessment (MoCA) were performed by each AUD participant. Based on the BEARNI score, two groups of AUD patients were studied: AUD patients with no or mild cognitive impairment (AUD COG+), and AUD patients with moderate-to-severe cognitive impairment (AUD COG-).Results: In WB, Th concentrations were significantly higher, and percentages of phosphate esters of thiamine were significantly lower in AUD COG- patients compared to controls. In serum, Th concentrations were significantly higher in AUD COG- patients compared to controls. The percentage of Th in serum was significantly higher in AUD COG- patients compared to AUD COG+ patients, and to the groups of controls. When adjusted on education level, the percentage of Th in serum in AUD patients negatively correlated with the scores at BEARNI and MoCA, and Th concentration in serum negatively correlated with MoCA.Conclusions: These data support an impairment of metabolism and/or distribution of thiamine in AUD patients, and a relationship with the development of alcohol-related cognitive deficits.

Neuroimaging in alcohol use disorder: From mouse to man

This article provides an overview of recent advances in understanding the effects of alcohol use disorders (AUD) on the brain from the perspective of magnetic resonance imaging (MRI) research in preclinical models and clinical studies. As a noninvasive investigational tool permitting assessment of morphological, metabolic, and hemodynamic changes over time, MRI offers insight into the dynamic course of alcoholism beginning with initial exposure through periods of binge drinking and escalation, sobriety, and relapse and has been useful in differential diagnosis of neurological diseases associated with AUD. Structural MRI has revealed acute and chronic effects of alcohol on both white and gray matter volumes. MR Spectroscopy, able to quantify brain metabolites in vivo, has shed light on biochemical alterations associated with alcoholism. Diffusion tensor imaging permits microstructural characterization of white matter fiber tracts. Functional MRI has allowed for elucidation of hemodynamic responses at rest and during task engagement. Positron emission tomography, a non-MRI imaging tool, has led to a deeper understanding of alcohol-induced receptor and neurotransmitter changes during various stages of drinking and abstinence. Together, such in vivo imaging tools have expanded our understanding of the dynamic course of alcoholism including evidence for regional specificity of the effects of AUD, hints at mechanisms underlying the shift from casual to compulsive use of alcohol, and profound recovery with sustained abstinence.

A Pivotal Role for Thiamine Deficiency in the Expression of Neuroinflammation Markers in Models of Alcohol-Related Brain Damage

BACKGROUND

Alcohol-related brain damage (ARBD) is associated with neurotoxic effects of heavy alcohol use and nutritional deficiency, in particular thiamine deficiency (TD), both of which induce inflammatory responses in brain. Although neuroinflammation is a critical factor in the induction of ARBD, few studies have addressed the specific contribution(s) of ethanol (EtOH) versus TD.

METHODS

Adult rats were randomly divided into 6 conditions: chronic EtOH treatment (CET) where rats consumed a 20% v/v solution of EtOH for 6 months; CET with injections of thiamine (CET + T); severe pyrithiamine-induced TD (PTD); moderate PTD; moderate PTD during CET; and pair-fed controls. After the treatments, the rats were split into 3 recovery phase time points: the last day of treatment (time point 1), acute recovery (time point 2: 24 hours posttreatment), and delayed recovery (time point 3: 3 weeks posttreatment). At these time points, vulnerable brain regions (thalamus, hippocampus, frontal cortex) were collected and changes in neuroimmune markers were assessed using a combination of reverse transcription polymerase chain reaction and protein analysis.

RESULTS

CET led to minor fluctuations in neuroimmune genes, regardless of the structure being examined. In contrast, PTD treatment led to a profound increase in neuroimmune genes and proteins within the thalamus. Cytokine changes in the thalamus ranged in magnitude from moderate (3-fold and 4-fold increase in interleukin-1β [IL-1β] and IκBα) to severe (8-fold and 26-fold increase in tumor necrosis factor-α and IL-6, respectively). Though a similar pattern was observed in the hippocampus and frontal cortex, overall fold increases were moderate relative to the thalamus. Importantly, neuroimmune gene induction varied significantly as a function of severity of TD, and most genes displayed a gradual recovery across time.

CONCLUSIONS

These data suggest an overt brain inflammatory response by TD and a subtle change by CET alone. Also, the prominent role of TD in the immune-related signaling pathways leads to unique regional and temporal profiles of induction of neuroimmune genes.

A Case of Wernicke Encephalopathy Developing After Ileal Bypass Surgery

Wernicke encephalopathy is an acute neurological problem resulting from thiamine deficiency and manifesting with mental confusion, oculomotor dysfunction, and ataxia. It is associated with alcohol dependence in adults. Preparatory factors include hyperemesis gravidarum, prolonged diarrhea, prolonged parental nutrition without vitamin support, absorption disorders, anorexia, cancer, and chemotherapy. Failure to consider the clinical findings and preparatory factors of this disease, which is rare in children, can delay diagnosis. This report describes a case of Wernicke encephalopathy developing in a patient with brid ileus and receiving total parenteral nutrition after partial ileal bypass surgery. The patient's clinical and cranial magnetic resonance findings were compatible with Wernicke encephalopathy. Although these are not widespread, typical ocular findings for Wernicke encephalopathy were present. Dramatic improvements were observed in clinical, ocular, and cranial magnetic resonance findings after treatment.

Amprolium exposure alters mice behavior and metabolism in vivo

BACKGROUND

Thiamine deficiency (TD) models have been developed, mainly using the thiamine analog pyrithiamine. Other analogs have not been used in rodents. We aimed to evaluate the effects and mechanisms of intraperitoneal (ip) amprolium-induced TD in mice. We also evaluated the associated pathogenesis using antioxidant and anti-inflammatory compounds (Trolox, dimethyl sulfoxide).

METHODS

Male mice were separated into two groups, one receiving a standard diet (control animals), and the other a TD diet (deficient groups) for 20 days. Control mice were further subdivided into three groups receiving daily ip injections of saline (NaCl 0.9%; Cont group), Tolox (Tr group) or dimethyl sulfoxide (DMSO; Dmso group). The three TD groups received amprolium (Amp group), amprolium and Trolox (Amp+Tr group), or amprolium and DMSO (Amp+Dmso group). The animals were subjected to behavioral tests and then euthanized. The brain and viscera were analyzed.

RESULTS

Amprolium exposure induced weight loss with hyporexia, reduced the behavioral parameters (locomotion, exploratory activity, and motor coordination), and induced changes in the brain (lower cortical cell viability) and liver (steatosis). Trolox co-treatment partially improved these conditions, but to a lesser extent than DMSO.

CONCLUSIONS

Amprolium-induced TD may be an interesting model, allowing the deficiency to develop more slowly and to a lesser extent. Amprolium exposure also seems to involve oxidative stress and inflammation, suggested as the main mechanisms of cell dysfunction in TD.

Stabilization of the hypoxia-inducible transcription Factor-1 alpha (HIF-1α) in thiamine deficiency is mediated by pyruvate accumulation

Vitamin B1, or thiamine is a critical enzyme cofactor required for metabolic function and energy production. Thiamine deficiency (TD) is common in various diseases, and results in severe neurological complications due to diminished mitochondrial function, oxidative stress, excitotoxicity and inflammation. These pathological sequelae result in apoptotic cell death in both neurons and astrocytes in distinct regions, in particular the thalamus and mammillary bodies. Comparable histological injuries in patients with hypoxia/ischemia (H/I) have also been described, suggesting a congruency between the cellular responses to these stresses. Analogous to H/I, TD stabilizes and activates Hypoxia Inducible Factor-1α (HIF-1α) even without changes in physiological oxygen levels. However, the mechanism of HIF-1α stabilization in TD is currently unknown. Using a pyruvate assay, we have demonstrated that TD induces pyruvate accumulation in mouse primary astrocytes which correlates to an increase in HIF-1α expression. Additionally, we utilized an enzymatic assay for pyruvate dehydrogenase to demonstrate a reduction in catalytic activity during TD due to lack of available thiamine pyrophosphate cofactor, resulting in the observed pyruvate accumulation. Finally, a pyruvate kinase inhibitor which limited pyruvate accumulation was utilized to demonstrate the role of pyruvate accumulation in HIF-1α stabilization during TD. These results reveal that stabilization of HIF-1α protein in TD centralizes on pyruvate accumulation in mouse primary astrocytes due to metabolic disruption of PDH.

Dan-Lou Prescription Inhibits Foam Cell Formation Induced by ox-LDL via the TLR4/NF-κB and PPARγ Signaling Pathways

Atherosclerosis is the major worldwide cause of mortality for patients with coronary heart disease. Many traditional Chinese medicine compound prescriptions for atherosclerosis treatment have been tried in patients. Dan-Lou prescription, which is improved from Gualou-Xiebai-Banxia decoction, has been used to treat chest discomfort (coronary atherosclerosis) for approximately 2,000 years in China. Although the anti-inflammatory activities of Dan-Lou prescription have been proposed previously, the mechanism remains to be explored. Based on the interaction between inflammation and atherosclerosis, we further investigated the effect of Dan-Lou prescription on macrophage-derived foam cell formation and disclosed the underlying mechanisms. In the oxidative low-density lipoprotein (ox-LDL) induced foam cells model using murine macrophage RAW 264.7 cells, the ethanol extract from Dan-Lou prescription (EEDL) reduced ox-LDL uptake and lipid deposition by inhibiting the protein and mRNA expression of Toll-like receptor (TLR)4 and scavenger receptor (SR)B1. After stimulation with ox-LDL, the metabolic profile of macrophages was also changed, while the intervention of the EEDL mainly regulated the metabolism of isovalerylcarnitine, arachidonic acid, cholesterol, aspartic acid, arginine, lysine, L-glutamine and phosphatidylethanolamine (36:3), which participated in the regulation of the inflammatory response, lipid accumulation and cell apoptosis. In total, 27 inflammation-related gene targets were screened, and the biological mechanisms, pathways and biological functions of the EEDL on macrophage-derived foam cells were systemically analyzed by Ingenuity Pathway Analysis system (IPA). After verification, we found that EEDL alleviated ox-LDL induced macrophage foam cell formation by antagonizing the mRNA and protein over-expression of PPARγ, blocking the phosphorylation of IKKα/β, IκBα and NF-κB p65 and maintaining the expression balance between Bax and Bcl-2. In conclusion, we provided evidences that Dan-Lou prescription effectively attenuated macrophage foam cell formation via the TLR4/NF-κB and PPARγ signaling pathways.

Wernicke's Encephalopathy as a Rare Complication of Hyperemesis Gravidarum: A Case Report and Review of Literature

Wernicke's encephalopathy (WE) is a rare neurological syndrome that presents in the setting of thiamine deficiency. Though alcoholism is the most common cause of this condition, a few other etiologies include malnutrition from other causes, hemodialysis, and hyperemesis gravidarum. In this case report, we aim to report a case of a young woman who developed WE in the setting of hyperemesis gravidarum (HG) that improved with thiamine replacement. This manuscript details her presentation and clinical examination and includes a spontaneous upbeat nystagmus and goes over the condition along with a review of the literature.

Vitamin B1 in critically ill patients: needs and challenges

BACKGROUND

Thiamine has a crucial role in energy production, and consequently thiamine deficiency (TD) has been associated with cardiac failure, neurological disorders, oxidative stress (lactic acidosis and sepsis) and refeeding syndrome (RFS). This review aims to explore analytical methodologies of thiamine compound quantification and highlight similarities, variances and limitations of current techniques and how they may be relevant to patients.

CONTENT

An electronic search of Medline, PubMed and Embase databases for original articles published in peer-reviewed journals was conducted. MethodsNow was used to search for published analytical methods of thiamine compounds. Keywords for all databases included "thiamine and its phosphate esters", "thiamine methodology" and terms related to critical illness. Enquiries were also made to six external quality assurance (EQA) programme organisations for the inclusion of thiamine measurement.

SUMMARY

A total of 777 published articles were identified; 122 were included in this review. The most common published method is HPLC with florescence detection. Two of the six EQA organisations include a thiamine measurement programme, both measuring only whole-blood thiamine pyrophosphate (TPP). No standard measurement procedure for thiamine compound quantification was identified.

OUTLOOK

Overall, there is an absence of standardisation in measurement methodologies for thiamine in clinical care. Consequently, multiple variations in method practises are prohibiting the comparison of study results as they are not traceable to any higher order reference. Traceability of certified reference materials and reference measurement procedures is needed to provide an anchor to create the link between studies and help bring consensus on the clinical importance of thiamine.

Thiamine deficiency activates hypoxia inducible factor-1α to facilitate pro-apoptotic responses in mouse primary astrocytes

Thiamine is an essential enzyme cofactor required for proper metabolic function and maintenance of metabolism and energy production in the brain. In developed countries, thiamine deficiency (TD) is most often manifested following chronic alcohol consumption leading to impaired mitochondrial function, oxidative stress, inflammation and excitotoxicity. These biochemical lesions result in apoptotic cell death in both neurons and astrocytes. Comparable histological injuries in patients with hypoxia/ischemia and TD have been described in the thalamus and mammillary bodies, suggesting a congruency between the cellular responses to these stresses. Consistent with hypoxia/ischemia, TD stabilizes and activates Hypoxia Inducible Factor-1α (HIF-1α) under physiological oxygen levels. However, the role of TD-induced HIF-1α in neurological injury is currently unknown. Using Western blot analysis and RT-PCR, we have demonstrated that TD induces HIF-1α expression and activity in primary mouse astrocytes. We observed a time-dependent increase in mRNA and protein expression of the pro-apoptotic and pro-inflammatory HIF-1α target genes MCP1, BNIP3, Nix and Noxa during TD. We also observed apoptotic cell death in TD as demonstrated by PI/Annexin V staining, TUNEL assay, and Cell Death ELISA. Pharmacological inhibition of HIF-1α activity using YC1 and thiamine repletion both reduced expression of pro-apoptotic HIF-1α target genes and apoptotic cell death in TD. These results demonstrate that induction of HIF-1α mediated transcriptional up-regulation of pro-apoptotic/inflammatory signaling contributes to astrocyte cell death during thiamine deficiency.

Thiamine supplementation facilitates thiamine transporter expression in the rumen epithelium and attenuates high-grain-induced inflammation in low-yielding dairy cows

An experiment was conducted to uncover the effects of increasing dietary grain levels on expression of thiamine transporters in ruminal epithelium, and to assess the protective effects of thiamine against high-grain-induced inflammation in dairy cows. Six rumen-fistulated, lactating Holstein dairy cows (627 ± 16.9 kg of body weight, 180 ± 6 d in milk; mean ± standard deviation) were randomly assigned to a replicated 3 × 3 Latin square design trial. Three treatments were control (20% dietary starch, dry matter basis), high-grain diet (HG, 33.2% dietary starch, DM basis), and HG diet supplemented with 180 mg of thiamine/kg of dry matter intake. On d 19 and 20 of each period, milk performance was measured. On d 21, ruminal pH, endotoxic lipopolysaccharide (LPS), and thiamine contents in rumen and blood, and plasma inflammatory cytokines were detected; a rumen papillae biopsy was taken on d 21 to determine the gene and protein expression of toll-like receptor 4 (TLR4) signaling pathways. The HG diet decreased ruminal pH (5.93 vs. 6.49), increased milk yield from 17.9 to 20.2 kg/d, and lowered milk fat and protein from 4.28 to 3.83%, and from 3.38 to 3.11%, respectively. The HG feeding reduced thiamine content in rumen (2.89 vs. 8.97 μg/L) and blood (11.66 vs. 17.63 μg/L), and the relative expression value of thiamine transporter-2 (0.37-fold) and mitochondrial thiamine pyrophosphate transporter (0.33-fold) was downregulated by HG feeding. The HG-fed cows exhibited higher endotoxin LPS in rumen fluid (134,380 vs. 11,815 endotoxin units/mL), and higher plasma concentrations of lipopolysaccharide binding protein and pro-inflammatory cytokines when compared with the control group. The gene and protein expression of tumor necrosis factor α (TNFα), IL1B, and IL6 in rumen epithelium increased when cows were fed the HG diet, indicating that local inflammation occurred. The depressions in ruminal pH, milk fat, and protein of HG-fed cows were reversed by thiamine supplementation. Thiamine supplementation increased thiamine contents in rumen and blood, and also upregulated the relative expression of thiamine transporters compared with the HG group. Thiamine supplementation decreased ruminal LPS (49,361 vs. 134,380 endotoxin units/mL) and attenuated the HG-induced inflammation response as indicated by a reduction in plasma IL6, and decreasing gene and protein expression of pro-inflammatory cytokines in rumen epithelium. Western bottling analysis showed that thiamine suppressed the protein expression of TLR4 and the phosphorylation of nuclear factor kappa B (NFκB) unit p65. In conclusion, HG feeding inhibits thiamine transporter expression in ruminal epithelium. Thiamine could attenuate the epithelial inflammation during high-grain feeding, and the protective effects may be due to its ability to suppress TLR4-mediated NFκB signaling pathways.