Thiamine and benfotiamine: Focus on their therapeutic potential

Therapeutic Potential of Vascular Adhesion Protein-1 (VAP-1)/Semicarbazide-Sensitive Amine Oxidase (SSAO) Inhibitors: Current Medicinal Chemistry and Emerging Opportunities

Semicarbazide-sensitive amine oxidase (SSAO) is a vascular enzyme and expressed in high concentrations in vascular smooth muscle cells (VSMCs), localized in the caveolae of the plasma membrane, and the endothelial cells. SSAO is classified as a copper amine oxidase and encoded by the amine oxidase copper-containing 3 gene. SSAO exists both as a soluble protein and as a tissue-bound transmembrane protein. The latter is often called vascular adhesion protein 1. Vascular adhesion protein-1 or VAP-1, encoded by the AOC3 gene, is a pro-inflammatory and multifunctional molecule belonging to the SSAO family. It assists the transformation of primary amines to aldehydes resulting in the production of hydrogen peroxide and ammonia. Work from the last two decades, has shown that VAP-1/SSAO plays a role in several physiological and pathological processes, making it a potentially valuable target for therapeutic development. In this review, we provide a detailed overview of the inhibitors of VAP-1/SSAO that are being developed specifically for the treatment of inflammatory diseases. Here in we have highlighted important aspects of the compounds investigated in therapeutic applications. Furthermore, we have outlined potential avenues for innovation with the aim of maximizing the therapeutic efficacy of VAP-1/SSAO inhibitors in clinical settings.

A Systematic Review of Thiamine Supplementation in Improving Diabetes and Its Related Cardiovascular Dysfunction

The significance of thiamine in human health is linked to its role in several pathways that control different disease processes. Significant improvements in cardiometabolic diseases, substantially impacted by thiamine imbalances, are observed with thiamine supplementation. Diabetic patients could see a reduction in cardiovascular (CV) risk due to thiamine's significant impact on glucose metabolism. Specifically, increased ventricular filling pressures and oxygen consumption, indicative of CV dysfunction, are caused by oxidative and inflammatory damage to blood vessels, diabetic nephropathy, and elevated lactic acid production. Despite promising pre-clinical results for thiamine, clinical trials have yielded conflicting and contradictory findings due to limitations like small sample sizes and insufficient follow-up. To provide a summary of clinical study results, this systematic review assessed the impact of thiamine supplementation on diabetes and its CV complications. The studies included in this systematic review were retrieved from PubMed and Medline databases, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and following the Population Intervention Comparison Outcome (PICO) framework. Seven clinical studies were identified, which enlighten the association between thiamine supplementation, hyperglycemia, and cardiovascular disease (CVD). Although large-scale, multicenter studies with longer follow-up periods are needed, the association between thiamine and chronic metabolic dysfunction related to CV risk suggests its crucial role in preventing severe heart failure (HF).

Diagnostic yield of laboratory testing in hospitalized older adults with altered mental status

BACKGROUND

Altered mental status (AMS) is a common cause of hospitalization among older adults, with a wide range of potential etiologies. However, the diagnostic and therapeutic yield of routine laboratory testing in such patients is unknown.

METHODS

In a retrospective cohort of inpatient hospital admissions to a large academic medical center from 2017 to 2022 of patients 65 years and older for whom the admitting diagnosis was AMS, we assessed laboratory testing for thyroid stimulating hormone (TSH), syphilis, vitamin B12, folate, vitamin C, vitamin D, zinc, niacin, and thiamine. We calculated the frequency of testing, rate of abnormal results, and rate of follow-up treatment.

RESULTS

Of the 3169 patients, 2312 (73 %) received at least one designated lab, and overall, 12 % of labs were abnormal. Labs varied in frequency of use (0.2 % for niacin-66 % for TSH) and rate of abnormality (0 % for niacin-71 % for zinc). 16 % of abnormal index labs led to a new prescription at discharge. The most common tests - TSH, folate, and B12- were of relatively low diagnostic and therapeutic utility. Tests that were less common-zinc, vitamin D, and vitamin C-were more commonly abnormal. 3.8 % of patients tested for syphilis had abnormal results, and 72 % of patients with an abnormal result received treatment with penicillin during the index hospitalization.

CONCLUSIONS

These analyses suggest that commonly obtained labs in the workup of AMS have varied diagnostic and therapeutic utility. The contribution of observed laboratory abnormalities to a patients' AMS warrants further study to improve the delivery of high-value care.

The Pivotal Role of Thiamine Supplementation in Counteracting Cardiometabolic Dysfunctions Associated with Thiamine Deficiency

The isolation, structural elucidation, and synthesis of pure thiamin were achieved in 1936, marking a milestone in vitamin research. As an organic compound soluble in water, thiamin is essential for carbohydrate metabolism in plants and animals, and in its active form-as part of the thiamin pyrophosphate coenzyme-performs these functions. Thereby, thiamin represents an essential vitamin to human health and is involved in several pathways that regulate several pathophysiological mechanisms. Cardiovascular disease is significantly impacted by thiamine imbalance and its supplementation offers substantial improvements to the associated conditions. In this comprehensive review, we aimed to examine the dual role of thiamine deficiency and accumulation, focusing on an analysis of the causes of thiamine deficiency. We detailed the effects of thiamine deficiency on metabolism and on cardiovascular risk and heart failure, explaining the molecular mechanisms involved in metabolic dysfunction, and highlighting the role of B1 vitamin supplementation in diabetes mellitus management and atherosclerosis development and progression. Indeed, B1 supplementation counteracts oxidative stress and inflammation, significantly ameliorating glycemic and lipemic profiles. Additionally, we reported the beneficial effects of thiamine in counteracting cardiotoxicity induced by cancer therapy. Although preclinical data strongly support the benefits of thiamine, clinical trial findings are in contrast and contradictory, hampered by limitations such as small sample sizes and inadequate follow-up. Further research is needed to investigate thiamine's potential benefits, overcoming current study limitations and evaluating its use as a supplemental therapy alongside standard treatments in different high-cardiovascular-risk conditions.

Benfotiamine Ameliorates Streptozotocin-Induced Alzheimer's Disease in Rats by Modulating Neuroinflammation, Oxidative Stress, and Microglia

Alzheimer's disease (AD) is the most prevalent cause of dementia, characterized by progressive memory loss and cognitive decline. Recent evidence indicates that inflammation plays a central role in AD pathogenesis, with elevated inflammatory markers and risk genes linked to innate immune functions. Glial cell dysfunction, particularly in astrocytes and microglia, is crucial to the neuroinflammatory process, contributing to oxidative stress, synaptic dysfunction, neuronal death, and impaired neurogenesis. This study aimed to investigate the therapeutic effects of benfotiamine (BFT), a vitamin B1 analogue, on microglial morphology, inflammation, and oxidative stress parameters in a sporadic Alzheimer-like disease model induced by intracerebroventricular injection of streptozotocin (STZ). Supplementation with 150 mg/kg of BFT for 7 days significantly reduced inflammation in the hippocampus and provided protection against oxidative damage in the entorhinal cortex by activating the Nrf-2 pathway and enhancing the expression of antioxidant enzymes such as SOD1 and CAT. These findings suggest that BFT exerts neuroprotective effects in AD, particularly impacting glial cell function and redox homeostasis.

Rare Diseases Linked to Mutations in Vitamin Transporters Expressed in the Human Blood-Brain Barrier

Recent advances have significantly enhanced our understanding of the role of membrane transporters in drug disposition, particularly focusing on their influence on pharmacokinetics, and consequently, pharmacodynamics. The relevance of these transporters in clinical pharmacology is well acknowledged. Recent research has also underscored the critical role of membrane transporters as targets in human diseases, including their involvement in rare genetic disorders. This review focuses on transporters for water-soluble B vitamins, such as thiamine, riboflavin, and biotin, essential cofactors for metabolic enzymes. Mutations in transporters, such as SLC19A3 (thiamine), SLC52A2, and SLC52A3 (riboflavin), and SLC5A6 (multiple B vitamins including pantothenic acid and biotin) are linked to severe neurological disorders due to their role in the blood-brain barrier, which is crucial for brain vitamin supply. Current treatments, mainly involving vitamin supplementation, often result in variable response. This review also provides a short perspective on the role of the transporters in the blood-cerebrospinal fluid barrier and highlights the potential development of pharmacologic treatments for rare disorders associated with mutations in these transporters.

The relationship between dietary vitamin B1 intake and severe abdominal aortic calcification among the general population in the United States

Background

Vitamin B1 deficiency is closely associated with vascular system damage, but the relationship between dietary vitamin B1 intake and abdominal aortic calcification (AAC) remains unclear and warrants further investigation.

Methods

2,640 participants from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 were included in the study. Severe AAC was defined as Kauppila score >5. Multivariable logistic regression analysis and restricted cubic splines (RCS) were used to examine the relationship between dietary vitamin B1 and severe AAC.

Results

The increase in dietary intake of vitamin B1 is significantly correlated with a decrease in the risk of severe AAC (OR: 0.601, 95% CI: 0.406, 0.892). Compared to the first quartile of dietary vitamin B1 intake, the fourth quartile had a significantly reduced risk of severe AAC (OR: 0.358, 95% CI: 0.172, 0.744). RCS indicated a decreasing trend in the risk of severe AAC with increasing dietary vitamin B1 intake.

Conclusion

Our research findings indicate that the increase in dietary intake of vitamin B1 is significantly associated with a decrease in the risk of severe AAC. Thus, increasing dietary vitamin B1 intake appropriately may reduce the risk of severe AAC.

Management of Alzheimer's disease and related neurotoxic pathologies: Role of thiamine, pyridoxine and cobalamin

Alzheimer's disease (AD) remains one of the most debilitating disease and most common neurological disorder in the world at large. However, with many years of multiple research and billions of dollars invested for the purpose of research, not many therapeutic options exist for the management of this disease. As at 2023, the number has only increased to 7, one of which is a combination of two existing therapies. However, research has continued still in the search for a cure. The roles and functions of thiamine, pyridoxine and cobalamin in the proper function of the nervous system has been well researched over time and their role in the management of neurological diseases have been of interest in the last decade. This review describes the roles of the aforementioned chemicals in the management of different models of AD and AD-like pathologies as mono-therapeutic agents and prospective adjuvant for combination therapy.

Emerging paradigms in Alzheimer's therapy

Alzheimer's disease is a neurodegenerative disorder that affects elderly, and its incidence is continuously increasing across the globe. Unfortunately, despite decades of research, a complete cure for Alzheimer's disease continues to elude us. The current medications are mainly symptomatic and slow the disease progression but do not result in reversal of all disease pathologies. The growing body of knowledge on the factors responsible for the onset and progression of the disease has resulted in the identification of new targets that could be targeted for treatment of Alzheimer's disease. This has opened new vistas for treatment of Alzheimer's disease that have moved away from chemotherapeutic agents modulating a single target to biologics and combinations that acted on multiple targets thereby offering better therapeutic outcomes. This review discusses the emerging directions in therapeutic interventions against Alzheimer's disease highlighting their merits that promise to change the treatment paradigm and challenges that limit their clinical translation.

The protective effect of benfotiamine on gastric ulcers in male rats: an experimental study

Gastric ulcers are a common gastrointestinal disorder associated with significant morbidity and mortality. It can also increase the risk of gastric cancer. This study aimed to investigate the effect of benfotiamine on experimentally-induced gastric ulcers in male rats. In this study, 30 Wistar male rats were divided randomly into six groups: control (normal), indomethacin, omeprazole, and treatment groups, including 50, 100, and 200 mg/kg of benfotiamine. Gastric ulcer was induced by indomethacin gavage. Omeprazole and different therapeutic doses of benfotiamine were administered for three days. Twenty-four hours after the last treatment, the rats were euthanized, and samples were collected.The results demonstrated that 100 and 200 mg/kg of benfotiamine treatment significantly improved indomethacin-induced gastric tissue damage. Moreover, benfotiamine at 100 and 200 mg/kg effectively attenuated the levels of pro-inflammatory cytokines IL-6 and TNF-α and oxidative stress markers MDA and ROS while increasing the antioxidant GSH. These findings suggest that benfotiamine's gastroprotective effects are mediated through its antioxidant and anti-inflammatory properties, which help mitigate the tissue damage and inflammatory response associated with indomethacin-induced gastric ulcers.However, further research is needed to elucidate the precise molecular mechanisms underlying these beneficial effects and to evaluate the potential therapeutic application of benfotiamine in clinical settings.

L-shaped association of thiamine intake and risk for peripheral artery disease in US adults: a cross-sectional study

Background

The relationship between thiamine intake and risk for peripheral artery disease (PAD) is unknown. We aimed to clarify the role of thiamine intake on risk for PAD and the implications of this relationship. The secondary objective of this study is to explore the potential non-linear dose-response relationship between exposure to thiamine intake and outcome risk for PAD.

Methods

We conducted a cross-sectional study involving 6,112 participants with US adults from the National Health and Nutrition Examination Survey (1999-2004). Logistic regression and restricted cubic spline were utilized to substantiate the research objectives.

Results

The overall prevalence of risk for PAD was 7.9, 51% in males and 49% in females. After multivariable adjustment, lower thiamine intake was significantly and nonlinearly associated with higher risks of PAD among participants. Furthermore, we discovered L-shaped associations (p = 0.082) between thiamine intake and the risk of PAD, with an inflection point at 0.66 mg/day. Accordingly, in the threshold effect analysis, there was an inverse association between dietary thiamine intake and the risk in participants with dietary thiamine intake <0.65 mg/day. Compared to participants with thiamine intake below the inflection points, those with higher levels had a 31% lower risk for PAD (OR, 0.69; 95% CI: 0.51, 0.95). Further subgroup analysis showed no significant interactions between the subgroups (all p values for interaction were > 0.05).

Conclusion

A non-linear association was revealed, showing that low and high levels of thiamine intake were associated with an increased the risk of peripheral artery disease in American adults. The inflection point at 0.66 mg/day and lower risk of PAD at 0.65-1.13mg/day of dietary thiamine intake may represent intervention targets for lowering the risk of PAD. The findings of this study require further validation and confirmation.

Oxidative Stress and Cerebral Vascular Tone: The Role of Reactive Oxygen and Nitrogen Species

The brain's unique characteristics make it exceptionally susceptible to oxidative stress, which arises from an imbalance between reactive oxygen species (ROS) production, reactive nitrogen species (RNS) production, and antioxidant defense mechanisms. This review explores the factors contributing to the brain's vascular tone's vulnerability in the presence of oxidative damage, which can be of clinical interest in critically ill patients or those presenting acute brain injuries. The brain's high metabolic rate and inefficient electron transport chain in mitochondria lead to significant ROS generation. Moreover, non-replicating neuronal cells and low repair capacity increase susceptibility to oxidative insult. ROS can influence cerebral vascular tone and permeability, potentially impacting cerebral autoregulation. Different ROS species, including superoxide and hydrogen peroxide, exhibit vasodilatory or vasoconstrictive effects on cerebral blood vessels. RNS, particularly NO and peroxynitrite, also exert vasoactive effects. This review further investigates the neuroprotective effects of antioxidants, including superoxide dismutase (SOD), vitamin C, vitamin E, and the glutathione redox system. Various studies suggest that these antioxidants could be used as adjunct therapies to protect the cerebral vascular tone under conditions of high oxidative stress. Nevertheless, more extensive research is required to comprehensively grasp the relationship between oxidative stress and cerebrovascular tone, and explore the potential benefits of antioxidants as adjunctive therapies in critical illnesses and acute brain injuries.