Thiamine and Parkinson's disease

Adherence to Parkinson's disease medication: A case study to illustrate reasons for non-adherence, implications for practice and engaging under-represented participants in research

Parkinson's disease (PD) is a progressive neurodegenerative disease which primarily presents with the core symptoms of rigidity, postural instability, tremor, and bradykinesia. Non-adherence to prescribed PD treatments can have significant ramifications, such as poor symptom control and greater disease burden. Reasons for poor adherence are multifaceted, particularly when medication regimens are complex and often based on perceptual and practical barriers. Additionally, engaging fully non-adherent patients in research is challenging since they may have dropped out of service provision, yet their contribution is vital to fully understand the rationale for non-adherence. This paper aims to present a case study on the perspectives of one person with PD, a participant in a previously published qualitative study investigating the barriers and facilitators to medication adherence in PD. In this paper, the participant's diagnostic journey is described, and experiences of medical consultations are summarised to explain their reasons for not adhering to any of the standard UK PD treatments prescribed. The participant's preferences for using Vitamin B1 (thiamine) injections to manage the symptoms are reported and the rationale for doing so is discussed. We consider the case through the lens of a behavioural science approach, drawing on health psychology theory, the Theoretical Domains Framework (TDF), to inform the review and the practical challenges faced when analysing the data for this participant. Implications for pharmacy practice, in particular, are also put forward with view to ensuring that patients such as Mr. Wilkinson are provided with the opportunity to discuss treatment choices and self-management of long-term conditions such as PD. We also discuss the importance of reaching under-represented members of the population in medication adherence research, which embraces the principles of equality, diversity, and inclusion in research.

Parkinson's disease and vitamins: a focus on vitamin B12

Parkinson's disease (PD) has been linked to a vast array of vitamins among which vitamin B12 (Vit B12) is the most relevant and often investigated specially in the context of intrajejunal levodopa infusion therapy. Vit B12 deficiency, itself, has been reported to cause acute parkinsonism. Nevertheless, concrete mechanisms through which B12 deficiency interacts with PD in terms of pathophysiology, clinical manifestation and progression remains unclear. Recent studies have suggested that Vit B12 deficiency along with the induced hyperhomocysteinemia are correlated with specific PD phenotypes characterized with early postural instability and falls and more rapid motor progression, cognitive impairment, visual hallucinations and autonomic dysfunction. Specific clinical features such as polyneuropathy have also been linked to Vit B12 deficiency specifically in context of intrajejunal levodopa therapy. In this review, we explore the link between Vit B12 and PD in terms of physiopathology regarding dysfunctional neural pathways, neuropathological processes as well as reviewing the major clinical traits of Vit B12 deficiency in PD and Levodopa-mediated neuropathy. Finally, we provide an overview of the therapeutic effect of Vit B12 supplementation in PD and posit a practical guideline for Vit B12 testing and supplementation.

Emerging antioxidant therapies in Friedreich's ataxia

Friedreich's ataxia (FRDA) is a rare childhood neurologic disorder, affecting 1 in 50,000 Caucasians. The disease is caused by the abnormal expansion of the GAA repeat sequence in intron 1 of the FXN gene, leading to the reduced expression of the mitochondrial protein frataxin. The disease is characterised by progressive neurodegeneration, hypertrophic cardiomyopathy, diabetes mellitus and musculoskeletal deformities. The reduced expression of frataxin has been suggested to result in the downregulation of endogenous antioxidant defence mechanisms and mitochondrial bioenergetics, and the increase in mitochondrial iron accumulation thereby leading to oxidative stress. The confirmation of oxidative stress as one of the pathological signatures of FRDA led to the search for antioxidants which can be used as therapeutic modality. Based on this observation, antioxidants with different mechanisms of action have been explored for FRDA therapy since the last two decades. In this review, we bring forth all antioxidants which have been investigated for FRDA therapy and have been signed off for clinical trials. We summarise their various target points in FRDA disease pathway, their performances during clinical trials and possible factors which might have accounted for their failure or otherwise during clinical trials. We also discuss the limitation of the studies completed and propose possible strategies for combinatorial therapy of antioxidants to generate synergistic effect in FRDA patients.

Efficacy of vitamins B1 and B6 as an adjunctive therapy to lithium in bipolar-I disorder: A double-blind, randomized, placebo-controlled, clinical trial

BACKGROUND

The use of adjunctive therapy for bipolar disorder is increasingly considered to increase the efficacy of standard treatments. In this randomized clinical trial, we evaluated the effect of vitamins B1 and B6 in separate treatment arms on mood symptoms, cognitive status, and sleep quality in hospitalized patients with bipolar disorder in manic episodes.

METHOD

In addition to receiving standard lithium treatment, participants (N = 66) were randomized to one of three conditions: 100 mg of vitamin B1, 40 mg of vitamin B6, or placebo. Outcomes were assessed one and 8 weeks of daily treatment, including the Young Mania Rating Scale (YMRS), Pittsburgh Sleep Quality Scale (PSQI), and Mini-Mental State Examination (MMSE). This study was performed between December 2020 and September 2021 based on the registration code number IRCT20200307046712N1.

RESULTS

Vitamin B6 had a significant effect (P value < 0.025 as significant) on mood improvement compared to placebo (F (1, 27.42) = 30.25, P < 0.001, r = 0.72), but vitamin B1 had no significant effect on mood improvement compared to Placebo (F (1/35.68) = 4.76, P = 0.036, r = 0.34). The contrasts between groups on PSQI showed a significant effect (P value < 0.025 as significant) of vitamin B6 over placebo for sleep status improvement (F (1/32.91) = 16.24, P < 0.001, r = 0.57) and also a significant effect of vitamin B1 over placebo (F (1/41.21) = 13.32, P < 0.001, r = 0.49).

CONCLUSIONS

The use of vitamin B6 as an adjunctive therapy to lithium can be associated with the improvement of mood symptoms in patients with bipolar disorder in the midst of a manic episode.

Transcriptome-based biomarker prediction for Parkinson's disease using genome-scale metabolic modeling

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world. Identification of PD biomarkers is crucial for early diagnosis and to develop target-based therapeutic agents. Integrative analysis of genome-scale metabolic models (GEMs) and omics data provides a computational approach for the prediction of metabolite biomarkers. Here, we applied the TIMBR (Transcriptionally Inferred Metabolic Biomarker Response) algorithm and two modified versions of TIMBR to investigate potential metabolite biomarkers for PD. To this end, we mapped thirteen post-mortem PD transcriptome datasets from the substantia nigra region onto Human-GEM. We considered a metabolite as a candidate biomarker if its production was predicted to be more efficient by a TIMBR-family algorithm in control or PD case for the majority of the datasets. Different metrics based on well-known PD-related metabolite alterations, PD-associated pathways, and a list of 25 high-confidence PD metabolite biomarkers compiled from the literature were used to compare the prediction performance of the three algorithms tested. The modified algorithm with the highest prediction power based on the metrics was called TAMBOOR, TrAnscriptome-based Metabolite Biomarkers by On-Off Reactions, which was introduced for the first time in this study. TAMBOOR performed better in terms of capturing well-known pathway alterations and metabolite secretion changes in PD. Therefore, our tool has a strong potential to be used for the prediction of novel diagnostic biomarkers for human diseases.

Metabolomics Analysis Revealed Significant Metabolic Changes in Brain Cancer Cells Treated with Paclitaxel and/or Etoposide

Cancer of the central nervous system (CNS) is ranked as the 19th most prevalent form of the disease in 2020. This study aims to identify candidate biomarkers and metabolic pathways affected by paclitaxel and etoposide, which serve as potential treatments for glioblastoma, and are linked to the pathogenesis of glioblastoma. We utilized an untargeted metabolomics approach using the highly sensitive ultra-high-performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS) for identification. In this study, 92 and 94 metabolites in U87 and U373 cell lines were profiled, respectively. The produced metabolites were then analyzed utilizing t-tests, volcano plots, and enrichment analysis modules. Our analysis revealed distinct metabolites to be significantly dysregulated (nutriacholic acid, L-phenylalanine, L-arginine, guanosine, ADP, hypoxanthine, and guanine), and to a lesser extent, mevalonic acid in paclitaxel and/or etoposide treated cells. Furthermore, both urea and citric acid cycles, and metabolism of polyamines and amino acids (aspartate, arginine, and proline) were significantly enriched. These findings can be used to create a map that can be utilized to assess the antitumor effect of paclitaxel and/or etoposide within the studied cancer cells.

Using Taguchi Method to Determine the Optimum Conditions for Synthesizing Parapyruvate

The synthesis of parapyruvate is important for the analysis of the content in the pyruvate supplements and the study of aging-related neurodegenerative diseases. However, the pure parapyruvate crystal is not, as yet, commercially available. In this study, we applied the Taguchi's L9 orthogonal array to investigate the optimal conditions for the preparation of the pure parapyruvate by the alkaline treatment of the pyruvic acid and then followed it with the solvent crystallization steps. We were also interested in revealing the major factors that affect the yield for the synthesized pure parapyruvate crystals. In addition, the parapyruvate-inhibited enzyme kinetic of α-ketoglutarate dehydrogenase complex (KGDHC) was also investigated. We found that the pure parapyruvate could be obtained in combination with an alkaline treatment and two solvent crystallization steps. The main factors affecting the yield of the pure parapyruvate were the concentration of the pyruvic acid (the reactant), the pH of the alkali treatment, the type of solvent used for the crystallization and the volume ratio of solvent used for crystallization. Finally, the optimal conditions could prepare parapyruvate crystals with a high purity of 99.8% and a high yield of 72.8%. In addition, the results demonstrate that parapyruvate is a reversibly competitive inhibitor for KGDHC.

Treatment Options for Motor and Non-Motor Symptoms of Parkinson's Disease

Parkinson’s disease (PD) usually presents in older adults and typically has both motor and non-motor dysfunctions. PD is a progressive neurodegenerative disorder resulting from dopaminergic neuronal cell loss in the mid-brain substantia nigra pars compacta region. Outlined here is an integrative medicine and health strategy that highlights five treatment options for people with Parkinson’s (PwP): rehabilitate, therapy, restorative, maintenance, and surgery. Rehabilitating begins following the diagnosis and throughout any additional treatment processes, especially vis-à-vis consulting with physical, occupational, and/or speech pathology therapist(s). Therapy uses daily administration of either the dopamine precursor levodopa (with carbidopa) or a dopamine agonist, compounds that preserve residual dopamine, and other specific motor/non-motor-related compounds. Restorative uses strenuous aerobic exercise programs that can be neuroprotective. Maintenance uses complementary and alternative medicine substances that potentially support and protect the brain microenvironment. Finally, surgery, including deep brain stimulation, is pursued when PwP fail to respond positively to other treatment options. There is currently no cure for PD. In conclusion, the best strategy for treating PD is to hope to slow disorder progression and strive to achieve stability with neuroprotection. The ultimate goal of any management program is to improve the quality-of-life for a person with Parkinson’s disease.

Dibenzoylthiamine Has Powerful Antioxidant and Anti-Inflammatory Properties in Cultured Cells and in Mouse Models of Stress and Neurodegeneration

Thiamine precursors, the most studied being benfotiamine (BFT), have protective effects in mouse models of neurodegenerative diseases. BFT decreased oxidative stress and inflammation, two major characteristics of neurodegenerative diseases, in a neuroblastoma cell line (Neuro2a) and an immortalized brain microglial cell line (BV2). Here, we tested the potential antioxidant and anti-inflammatory effects of the hitherto unexplored derivative O,S-dibenzoylthiamine (DBT) in these two cell lines. We show that DBT protects Neuro2a cells against paraquat (PQ) toxicity by counteracting oxidative stress at low concentrations and increases the synthesis of reduced glutathione and NADPH in a Nrf2-independent manner. In BV2 cells activated by lipopolysaccharides (LPS), DBT significantly decreased inflammation by suppressing translocation of NF-κB to the nucleus. Our results also demonstrate the superiority of DBT over thiamine and other thiamine precursors, including BFT, in all of the in vitro models. Finally, we show that the chronic administration of DBT arrested motor dysfunction in FUS transgenic mice, a model of amyotrophic lateral sclerosis, and it reduced depressive-like behavior in a mouse model of ultrasound-induced stress in which it normalized oxidative stress marker levels in the brain. Together, our data suggest that DBT may have therapeutic potential for brain pathology associated with oxidative stress and inflammation by novel, coenzyme-independent mechanisms.

Faecal Transplantation, Pro- and Prebiotics in Parkinson's Disease; Hope or Hype?

Abstract Faecal microbiome transplantation (FMT) is an attractive technique, because the administration is relatively simple and in general has a mild adverse effect pattern. Moreover, FMT consists of a broad mixture, which could be beneficial, because at this moment it is not known what type of changes in the microbiome are needed. However, except from a few cases no clinical data in Parkinson’s disease (PD) is available yet. There is some indication that FMT might be beneficial in severe constipated PD patients, but the clinical data to support this are very scarce. So, actually there are no good data in the public domain to support FMT at this moment in PD patients. FMT at this moment is a black box with too many unanswered questions, also with respect to safety concerns. Only the administration of species of Lactobacillus and Bifidobacterium over a time period of four to twelve weeks has repeatedly proven to be effective in treating constipation in PD. Also, no solid clinical data are available about the possible effects of probiotic treatment on motor symptoms or progression of PD. Therefore, also probiotic treatments in PD should wait until better clinical data become available, in order to select the right target populations and to have good estimates of the clinical effects to be expected.

Low plasma thiamine and phosphate in male patients with Parkinson's disease is associated with mild cognitive impairment

OBJECTIVES

Thiamine deficiency (TD) and phosphate depletion increase the risk for cognitive disturbances. This study investigates whether plasma levels of thiamine (P-THIAM), thiamine-monophosphate (P-TMP), and phosphate (P-PHOS) are associated with mild cognitive decline (MCI) in patients with Parkinson's disease (PD).

DESIGN AND STUDY POPULATION

This case-control study includes baseline data from a cohort of newly diagnosed patients identified in the New Parkinsonism in Umeå study (NYPUM) (N = 75) and an age and sex matched control group (n = 24).

MEASUREMENTS

Mini Nutritional Assessment (MNA-score) and concentrations of P-THIAM, P-TMP, and P-PHOS at baseline were compared between PD patients with mild cognitive impairment (PD-MCI) and PD patients with normal cognition (PD-NC). Neuropsychological assessments of MCI were performed at time of diagnosis.

RESULTS

Compared to patients with NC, patients with MCI had lower levels of P-THIAM and P-TMP as well as lower scores on both the Mini Mental State Examination (MMSE) and MNA-screening test. In addition, patients with MCI were older and had more motor problems. The multiple logistic regressions adjusted for age and sex revealed that higher levels of P-THIAM and the MNA-total score were associated with a lower risk of having MCI. Higher MNA-total score and higher P-THIAM and P-PHOS concentrations decreased the risk of MCI in male patients, but not in female patients. The decreased risk of MCI with higher P-TMP levels was lost after adding age and sex to the model. Bivariate correlations between P-PHOS and P-TMP were shown for the total PD population and controls as well as for males with MCI (r = 0.533; n = 22; p = 0.011), but not for males with NC (r = 0.314; n = 19; p = 0.204). An inverse partial correlation (adjusted for age, sex and UPDRS III) was shown for P-THIAM and MNA-total (r = -0.315,p = 0.009) and -final (part II) (r = -0.395,p = 0.001) score for the PD population (n = 75).

CONCLUSIONS

Higher P-THIAM and P-PHOS concentrations and higher MNA-total score were associated with a lower risk of MCI in male PD patients, findings that indicate that nutritional factors may influence cognitive function in males in the early phase of PD.

The prominent alteration in transcriptome and metabolome of Mycobacterium bovis BCG str. Tokyo 172 induced by vitamin B1

BACKGROUND

Vitamin B1 (VB1) is a crucial dietary nutrient and essential cofactor for several key enzymes in the regulation of cellular and metabolic processes, and more importantly in the activation of immune system. To date, the precise role of VB1 in Mycobacterium tuberculosis remains to be fully understood.

RESULTS

In this study, the transcriptional and metabolic profiles of VB1-treated Mycobacterium. bovis BCG were analyzed by RNA-sequencing and LC-MS (Liquid chromatography coupled to mass spectrometry). The selection of BCG strain was based on its common physiological features shared with M. tuberculosis. The results of cell growth assays demonstrated that VB1 inhibited the BCG growth rate in vitro. Transcriptomic analysis revealed that the expression levels of genes related to fatty acid metabolism, cholesterol metabolism, glycolipid catabolism, DNA replication, protein translation, cell division and cell wall formation were significantly downregulated in M. bovis BCG treated with VB1. In addition, the metabolomics LC-MS data indicated that most of the amino acids and adenosine diphosphate (ADP) were decreased in M. bovis BCG strain after VB1 treatment.

CONCLUSIONS

This study provides the molecular and metabolic bases to understand the impacts of VB1 on M.bovis BCG.

Redox nanoparticles: synthesis, properties and perspectives of use for treatment of neurodegenerative diseases

Oxidative stress (OS) and nitrative stress (NS) accompany many diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Antioxidants have been proposed to counteract OS/NS in these diseases. Nevertheless, the effects of antioxidants are limited and new, more efficient antioxidants are searched for. Redox-active nanoparticles (RNPs), containing antioxidants create a new therapeutical perspective. This review examines the recent literature describing synthesis and potential applications of cerium oxide RNPs, boron cluster-containing and silica containing RNPs, Gd₃N_@C₈₀ encapsulated RNPs, and concentrates on nitroxide-containing RNPs. Nitroxides are promising antioxidants, preventing inter alia glycation and nitration, but their application poses several problems. It can be expected that application of RNPs containing covalently bound nitroxides, showing low toxicity and able to penetrate the blood-brain barrier will be more efficient in the treatment of neurodegenerative disease, in particular AD and PD basing on their effects in cellular and animal models of neurodegenerative diseases.

Impact of Non-Enzymatic Glycation in Neurodegenerative Diseases: Role of Natural Products in Prevention

Non-enzymatic protein glycosylation is the addition of free carbonyls to the free amino groups of proteins, amino acids, lipoproteins and nucleic acids resulting in the formation of early glycation products. The early glycation products are also known as Maillard reaction which undergoes dehydration, cyclization and rearrangement to form advanced glycation end-products (AGEs). By and large the researchers in the past have also established that glycation and the AGEs are responsible for most type of metabolic disorders, including diabetes mellitus, cancer, neurological disorders and aging. The amassing of AGEs in the tissues of neurodegenerative diseases shows its involvement in diseases. Therefore, it is likely that inhibition of glycation reaction may extend the lifespan of an individual. The hunt for inhibitors of glycation, mainly using in vitro models, has identified natural compounds able to prevent glycation, especially polyphenols and other natural antioxidants. Extrapolation of results of in vitro studies on the in vivo situation is not straightforward due to differences in the conditions and mechanism of glycation, and bioavailability problems. Nevertheless, existing data allow postulating that enrichment of diet in natural anti-glycating agents may attenuate glycation and, in consequence may halt the aging and neurological problems.

Thiamine and selected thiamine antivitamins - biological activity and methods of synthesis

Thiamine plays a very important coenzymatic and non-coenzymatic role in the regulation of basic metabolism. Thiamine diphosphate is a coenzyme of many enzymes, most of which occur in prokaryotes. Pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase complexes as well as transketolase are the examples of thiamine-dependent enzymes present in eukaryotes, including human. Therefore, thiamine is considered as drug or diet supplement which can support the treatment of many pathologies including neurodegenerative and vascular system diseases. On the other hand, thiamine antivitamins, which can interact with thiamine-dependent enzymes impeding their native functions, thiamine transport into the cells or a thiamine diphosphate synthesis, are good propose to drug design. The development of organic chemistry in the last century allowed the synthesis of various thiamine antimetabolites such as amprolium, pyrithiamine, oxythiamine, or 3-deazathiamine. Results of biochemical and theoretical chemistry research show that affinity to thiamine diphosphate-dependent enzymes of these synthetic molecules exceeds the affinity of native coenzyme. Therefore, some of them have already been used in the treatment of coccidiosis (amprolium), other are extensively studied as cytostatics in the treatment of cancer or fungal infections (oxythiamine and pyrithiamine). This review summarizes the current knowledge concerning the synthesis and mechanisms of action of selected thiamine antivitamins and indicates the potential of their practical use.

Alpha-Synuclein Glycation and the Action of Anti-Diabetic Agents in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder with complex etiology and variable pathology. While a subset of cases is associated with single-gene mutations, the majority originates from a combination of factors we do not fully understand. Thus, understanding the underlying causes of PD is indispensable for the development of novel therapeutics. Glycation, the non-enzymatic reaction between reactive dicarbonyls and amino groups, gives rise to a variety of different reaction products known as advanced glycation end products (AGEs). AGEs accumulate over a proteins life-time, and increased levels of glycation reaction products play a role in diabetic complications. It is now also becoming evident that PD patients also display perturbed sugar metabolism and protein glycation, including that of alpha-synuclein, a key player in PD. Here, we hypothesize that anti-diabetic drugs targeting the levels of glycation precursors, or promoting the clearance of glycated proteins may also prove beneficial for PD patients.

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.

Intake of vitamin B before onset of Parkinson's disease and atypical parkinsonism and olfactory function at the time of diagnosis

BACKGROUND/OBJECTIVES

To investigate whether vitamin-B density in the diet 2-8 years before diagnosis is associated with olfactory function at the time of diagnosis.

SUBJECTS/METHODS

This prospective nested case-control study included patients with Parkinson's disease (PD), multiple system atrophy and progressive supranuclear paralysis identified between 2004 and 2009 in the county of Västerbotten in northern Sweden. The case database (NYPUM study; Newly Diagnosed Parkinson in Umeå; n=147) was cross-linked to the Northern Sweden Health and Disease Study (NSHDS). Identified patients (n=96) and controls (n=375) were matched for sex, age, year of health survey, sub-cohort and geographical area. Dietary intake was assessed by a food frequency questionnaire, and the brief smell identification test (B-SIT) was used to measure olfactory function at the time of diagnosis.

RESULTS

There was no difference in vitamin-B or any other macro- or micro-nutrient densities, energy intake or body mass index (kg/m²; BMI) between patients and controls at baseline at the time of the healthcare survey. A lower thiamin and folate density, amount per 1 megajoule, was reported in patients who scored below median on B-SIT (<7) when compared with that in patients who scored ⩾7 at the time of diagnosis. After adjusting for age, sex and BMI using linear and logistic regressions, an even stronger association was found between thiamin density and olfactory function.

CONCLUSIONS

A low thiamin and folate density in the reported diet, 2-8 years before PD diagnosis, was significantly associated with olfactory dysfunction at the time of PD diagnosis.

Effect of glycation inhibitors on aging and age-related diseases

Vast evidence supports the view that glycation of proteins is one of the main factors contributing to aging and is an important element of etiopathology of age-related diseases, especially type 2 diabetes mellitus, cataract and neurodegenerative diseases. Counteracting glycation can therefore be a means of increasing both the lifespan and healthspan. In this review, accumulation of glycation products during aging is presented, pathophysiological effects of glycation are discussed and ways of attenuation of the effects of glycation are described, concentrating on prevention of glycation. The effects of glycation and glycation inhibitors on the course of selected age-related diseases, such as Alzheimer's disease, Parkinson's disease and cataract are also reviewed.

Advances in clinical determinants and neurological manifestations of B vitamin deficiency in adults

B vitamin deficiency is a leading cause of neurological impairment and disability throughout the world. Multiple B vitamin deficiencies often coexist, and thus an understanding of the complex relationships between the different biochemical pathways regulated in the brain by these vitamins may facilitate prompter diagnosis and improved treatment. Particular populations at risk for multiple B vitamin deficiencies include the elderly, people with alcoholism, patients with heart failure, patients with recent obesity surgery, and vegetarians/vegans. Recently, new clinical settings that predispose individuals to B vitamin deficiency have been highlighted. Moreover, other data indicate a possible pathogenetic role of subclinical chronic B vitamin deficiency in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. In light of these findings, this review examines the clinical manifestations of B vitamin deficiency and the effect of B vitamin deficiency on the adult nervous system. The interrelationships of multiple B vitamin deficiencies are emphasized, along with the clinical phenotypes related to B vitamin deficiencies. Recent advances in the clinical determinants and diagnostic clues of B vitamin deficiency, as well as the suggested therapies for B vitamin disorders, are described.

Long-Term Treatment with High-Dose Thiamine in Parkinson Disease: An Open-Label Pilot Study

OBJECTIVES

To investigate the potential clinical, restorative, and neuroprotective effects of long-term treatment with thiamine in Parkinson disease (PD).

DESIGN

Observational open-label pilot study.

SETTING

Outpatient neurologic rehabilitation clinic.

PATIENTS AND METHODS

Starting in June 2012, we have recruited 50 patients with PD (33 men and 17 women; mean age, 70.4 ± 12.9 years; mean disease duration, 7.3 ± 6.7 years). All the patients were assessed at baseline with the Unified Parkinson's Disease Rating Scale (UPDRS) and the Fatigue Severity Scale (FSS) and began treatment with 100 mg of thiamine administered intramuscularly twice a week, without any change to personal therapy. All the patients were re-evaluated after 1 month and then every 3 months during treatment.

RESULTS

Thiamine treatment led to significant improvement of motor and nonmotor symptoms: mean UPDRS scores (parts I-IV) improved from 38.55 ± 15.24 to 18.16 ± 15.08 (p = 2.4 × 10(-14), t test for paired data) within 3 months and remained stable over time; motor UPDRS part III score improved from 22.01 ± 8.57 to 9.92 ± 8.66 (p = 3.1 × 10(-22)). Some patients with a milder phenotype had complete clinical recovery. FSS scores, in six patients who had fatigue, improved from 53.00 ± 8.17 to 23.60 ± 7.77 (p < 0.0001, t test for paired data). Follow-up duration ranged from 95 to 831 days (mean, 291.6 ± 207.2 days).

CONCLUSIONS

Administration of parenteral high-dose thiamine was effective in reversing PD motor and nonmotor symptoms. The clinical improvement was stable over time in all the patients. From our clinical evidence, we hypothesize that a dysfunction of thiamine-dependent metabolic processes could cause selective neural damage in the centers typically affected by this disease and might be a fundamental molecular event provoking neurodegeneration. Thiamine could have both restorative and neuroprotective action in PD.

Development of thiamine and pyridoxine loaded ferulic acid-grafted chitosan microspheres for dietary supplementation

Therapeutic potential of water soluble vitamins has been known for long and in recent times they are being widely supplemented in processed food. Phenolic acid-grafted chitosan derivatives can serve as excellent biofunctional encapsulating materials for these vitamins. As a proof of concept, thiamine and pyridoxine loaded ferulic acid-grafted chitosan microspheres were developed. Ferulic acid was successfully grafted on chitosan by a free radical mediated reaction and the structure was confirmed by FTIR and NMR analysis. When compared to FTIR spectra of chitosan, intensity of amide I (at around 1644 cm(-1)) and amide II (at around 1549 cm(-1)) bands in spectra of ferulic acid-grafted chitosan were found increased, indicating formation of new amide linkage. Strong signals at δ = 6.3-7.9 ppm corresponding to methine protons of ferulic acid were observed in NMR spectra of ferulic acid-grafted chitosan, suggesting the successful grafting of ferulic acid onto chitosan. Grafting ratio of the derivative was 263 mg ferulic acid equivalent/g polymer. Positively charged particles (zeta potential 31 mv) of mean diameter 4.5 and 4.8 μ, corresponding to number distribution and area distribution respectively were observed. Compact microspheres with smooth surfaces and no apparent cracks or pores were observed under scanning electron microscope. Efficient microencapsulation was further proved by X-ray diffraction patterns and thermal analysis. Preliminary anti-inflammatory activity of the vitamin-loaded microspheres was demonstrated.

Molecular mechanisms of the non-coenzyme action of thiamin in brain: biochemical, structural and pathway analysis

Thiamin (vitamin B1) is a pharmacological agent boosting central metabolism through the action of the coenzyme thiamin diphosphate (ThDP). However, positive effects, including improved cognition, of high thiamin doses in neurodegeneration may be observed without increased ThDP or ThDP-dependent enzymes in brain. Here, we determine protein partners and metabolic pathways where thiamin acts beyond its coenzyme role. Malate dehydrogenase, glutamate dehydrogenase and pyridoxal kinase were identified as abundant proteins binding to thiamin- or thiazolium-modified sorbents. Kinetic studies, supported by structural analysis, revealed allosteric regulation of these proteins by thiamin and/or its derivatives. Thiamin triphosphate and adenylated thiamin triphosphate activate glutamate dehydrogenase. Thiamin and ThDP regulate malate dehydrogenase isoforms and pyridoxal kinase. Thiamin regulation of enzymes related to malate-aspartate shuttle may impact on malate/citrate exchange, responsible for exporting acetyl residues from mitochondria. Indeed, bioinformatic analyses found an association between thiamin- and thiazolium-binding proteins and the term acetylation. Our interdisciplinary study shows that thiamin is not only a coenzyme for acetyl-CoA production, but also an allosteric regulator of acetyl-CoA metabolism including regulatory acetylation of proteins and acetylcholine biosynthesis. Moreover, thiamin action in neurodegeneration may also involve neurodegeneration-related 14-3-3, DJ-1 and β-amyloid precursor proteins identified among the thiamin- and/or thiazolium-binding proteins.

An association study between Heme oxygenase-1 genetic variants and Parkinson's disease

The blood-brain barrier (BBB) supplies brain tissues with nutrients, filters harmful compounds from the brain back to the bloodstream, and plays a key role in iron homeostasis in the human brain. Disruptions of the BBB are associated with several neurodegenerative conditions including Parkinson's disease (PD). Oxidative stress, iron deposition and mitochondrial impaired function are considered as risk factors for degeneration of the central nervous system. Heme oxygenase (HMOX) degrades heme ring to biliverdin, free ferrous iron and carbon monoxide being the rate-limiting activity in heme catabolism. The isoform HMOX1 is highly inducible in response to reactive oxygen species, which induce an increase in BBB permeability and impair its pathophysiology. Consequently, an over- expression of this enzyme may contribute to the marked iron deposition found in PD. We analyzed the HMOX1 SNPs rs2071746, rs2071747, and rs9282702, a microsatellite (GT)_n polymorphism and copy number variations in 691 patients suffering from PD and 766 healthy control individuals. Copy number variations in the HMOX1 gene exist, but these do not seem to be associated with PD risk. In contrast two polymorphisms that modify the transcriptional activity of the gene, namely a VNTR (GT)_n and the SNP rs2071746, are strongly associated with PD risk, particularly with the classic PD phenotype and with early onset of the disease. This study indicates that HMOX1 gene variants are associated to the risk of developing some forms of PD, thus adding new information that supports association of HMOX gene variations with PD risk.

Thiamin diphosphate-dependent enzymes: from enzymology to metabolic regulation, drug design and disease models

Bringing a knowledge of enzymology into research in vivo and in situ is of great importance in understanding systems biology and metabolic regulation. The central metabolic significance of thiamin (vitamin B1 ) and its diphosphorylated derivative (thiamin diphosphate; ThDP), and the fundamental differences in the ThDP-dependent enzymes of metabolic networks in mammals versus plants, fungi and bacteria, or in health versus disease, suggest that these enzymes are promising targets for biotechnological and medical applications. Here, the in vivo action of known regulators of ThDP-dependent enzymes, such as synthetic structural analogs of the enzyme substrates and thiamin, is analyzed in light of the enzymological data accumulated during half a century of research. Mimicking the enzyme-specific catalytic intermediates, the phosphonate analogs of 2-oxo acids selectively inhibit particular ThDP-dependent enzymes. Because of their selectivity, use of these compounds in cellular and animal models of ThDP-dependent enzyme malfunctions improves the validity of the model and its predictive power when compared with the nonselective and enzymatically less characterized oxythiamin and pyrithiamin. In vitro studies of the interaction of thiamin analogs and their biological derivatives with potential in vivo targets are necessary to identify and attenuate the analog selectivity. For both the substrate and thiamin synthetic analogs, in vitro reactivities with potential targets are highly relevant in vivo. However, effective concentrations in vivo are often higher than in vitro studies would suggest. The significance of specific inihibition of the ThDP-dependent enzymes for the development of herbicides, antibiotics, anticancer and neuroprotective strategies is discussed.

The beneficial role of thiamine in Parkinson disease

Parkinson disease (PD) is the second most common form of neurodegeneration among elderly individuals. PD is clinically characterized by tremors, rigidity, slowness of movement, and postural imbalance. In this paper, we review the evidence for an association between PD and thiamine. Interestingly, a significant association has been demonstrated between PD and low levels of serum thiamine, and thiamine supplements appear to have beneficial clinical effects against PD. Multiple studies have evaluated the connection between thiamine and PD pathology, and candidate pathways involve the transcription factor Sp1, p53, Bcl-2, caspase-3, tyrosine hydroxylase, glycogen synthase kinase-3β, vascular endothelial growth factor, advanced glycation end products, nuclear factor kappa B, mitogen-activated protein kinase, and the reduced form of nicotinamide adenine dinucleotide phosphate. Thus, a review of the literature suggests that thiamine plays a role in PD, although further investigation into the effects of thiamine in PD is needed.

Antioxidants reduce TGF-beta2-induced gene expressions in human optic nerve head astrocytes

PURPOSE

The goal of the present study was to investigate whether the antioxidants vitamin E, vitamin C and vitamin B1 can reduce the transforming growth factor-beta2 (TGF-β2)-induced gene expressions in cultured human optic nerve head (ONH) astrocytes.

METHODS

Cultured human ONH astrocytes were pretreated with different concentrations of vitamin E, vitamin C and vitamin B1 and then exposed to 1.0 ng/ml TGF-β2 for 24 hr. Expression of the heat shock proteins Hsp27 and αB-crystallin, the extracellular matrix (ECM) component fibronectin and the ECM-modulating protein connective tissue growth factor (CTGF) was detected by immunohistochemistry or real-time PCR analysis.

RESULTS

TGF-β2 increased the expression of Hsp27, αB-crystallin, fibronectin and CTGF in human ONH astrocytes. Pretreatment with different concentrations of vitamin E, vitamin C and vitamin B1 reduced the TGF-β2-stimulated gene expressions.

CONCLUSION

In cultured human ONH astrocytes, the TGF-β2-stimulated gene expressions could be reduced by pretreatment with vitamin E, vitamin C and vitamin B1. Therefore, the use of antioxidants in glaucomatous optic neuropathy might be a promising approach to prevent TGF-β2-induced cellular changes in ONH astrocytes.