In Vitro and In Silico Studies on Cytotoxic Properties of Oxythiamine and 2'-Methylthiamine

It is important to search for cytostatic compounds in order to fight cancer. One of them could be 2'-methylthiamine, which is a thiamine antimetabolite with an additional methyl group at the C-2 carbon of thiazole. So far, the cytostatic potential of 2'-methylthiamine has not been studied. We have come forward with a simplified method of synthesis using commercially available substrates and presented a comparison of its effects, as boosted by oxythiamine, on normal skin fibroblasts and HeLa cancer cells, having adopted in vitro culture techniques. Oxythiamine has been found to inhibit the growth and metabolism of cancer cells significantly better than 2'-methylthiamine (GI50 36 and 107 µM, respectively), while 2'-methylthiamine is more selective for cancer cells than oxythiamine (SI = 180 and 153, respectively). Docking analyses have revealed that 2'-methylthiamine (ΔG -8.2 kcal/mol) demonstrates a better affinity with thiamine pyrophosphokinase than thiamine (ΔG -7.5 kcal/mol ) and oxythiamine (ΔG -7.0 kcal/mol), which includes 2'-methylthiamine as a potential cytostatic. Our results suggest that the limited effect of 2'-methylthiamine on HeLa arises from the related arduous transport as compared to oxythiamine. Given that 2'-methylthiamine may possibly inhibit thiamine pyrophosphokinase, it could once again be considered a potential cytostatic. Thus, research should be carried out in order to find the best way to improve the transport of 2'-methylthiamine into cells, which may trigger its cytostatic properties.

Monitoring of glutathione using ratiometric fluorescent sensor based on MnO2 nanosheets simultaneously tuning the fluorescence of Rhodamine 6G and thiamine hydrochloride

L-glutathione (GSH) which has reducibility and integrated detoxification plays an important role in maintaining normal immune system function. Its abnormal levels are relevant to some clinical diseases. In this work, a facile ratiometric fluorescence sensor for GSH was designed based on MnO₂ nanosheets, Thiamine hydrochloride (VB₁) and Rhodamine 6G (R6G). VB₁ could be oxidized into fluorescent ox-VB₁ due to the strong oxidizing property of MnO₂, and MnO₂ nanosheets simultaneously could quench the fluorescence of R6G based on the inner filter effect (IFE). MnO₂ could react with GSH to form Mn²⁺, which caused its losing oxidizing property and quenching capacity. According to this principle, the concentration of ox-VB₁ diminished, resulting in its fluorescence intensity decreasing at 455 nm and the fluorescence of R6G recovering at 560 nm. Under optimal conditions, the VB₁-MnO₂-R6G detection system showed a wide linear range towards GSH in the range of 1.0-300.0 µmolL^-1 with a low detection limit reaching 0.52 µmolL^-1. Furthermore, the method was also applied in the determination of GSH in human serum.

BOND study: a randomised double-blind, placebo-controlled trial over 12 months to assess the effects of benfotiamine on morphometric, neurophysiological and clinical measures in patients with type 2 diabetes with symptomatic polyneuropathy

INTRODUCTION

Diabetic sensorimotor polyneuropathy (DSPN) affects approximately 30% of people with diabetes, while around half of cases are symptomatic. Currently, there are only few pathogenetically oriented pharmacotherapies for DSPN, one of which is benfotiamine, a prodrug of thiamine with a high bioavailability and favourable safety profile. While benfotiamine has shown positive effects in preclinical and short-term clinical studies, no long-term clinical trials are available to demonstrate disease-modifying effects on DSPN using a comprehensive set of disease-related endpoints.

METHODS AND ANALYSIS

The benfotiamine on morphometric, neurophysiological and clinical measures in patients with type 2 diabetes trial is a randomised double-blind, placebo-controlled parallel group monocentric phase II clinical trial to assess the effects of treatment with benfotiamine compared with placebo in participants with type 2 diabetes and mild to moderate symptomatic DSPN. Sixty participants will be 1:1 randomised to treatment with benfotiamine 300 mg or placebo two times a day over 12 months. The primary endpoint will be the change in corneal nerve fibre length assessed by corneal confocal microscopy (CCM) after 12 months of benfotiamine treatment compared with placebo. Secondary endpoints will include other CCM measures, skin biopsy and function indices, variables from somatic and autonomic nerve function tests, clinical examination and questionnaires, general health, health-related quality of life, cost, safety and blood tests.

ETHICS AND DISSEMINATION

The trial was approved by the competent authority and the local independent ethics committee. Trial results will be published in peer-reviewed journals, conference abstracts, and via online and print media.

TRIAL REGISTRATION NUMBER

DRKS00014832.

Multilevel Approach for the Treatment of Giardiasis by Targeting Arginine Deiminase

Giardiasis represents a latent problem in public health due to the exceptionally pathogenic strategies of the parasite Giardia lamblia for evading the human immune system. Strains resistant to first-line drugs are also a challenge. Therefore, new antigiardial therapies are urgently needed. Here, we tested giardial arginine deiminase (GlADI) as a target against giardiasis. GlADI belongs to an essential pathway in Giardia for the synthesis of ATP, which is absent in humans. In silico docking with six thiol-reactive compounds was performed; four of which are approved drugs for humans. Recombinant GlADI was used in enzyme inhibition assays, and computational in silico predictions and spectroscopic studies were applied to follow the enzyme's structural disturbance and identify possible effective drugs. Inhibition by modification of cysteines was corroborated using Ellman's method. The efficacy of these drugs on parasite viability was assayed on Giardia trophozoites, along with the inhibition of the endogenous GlADI. The most potent drug against GlADI was assayed on Giardia encystment. The tested drugs inhibited the recombinant GlADI by modifying its cysteines and, potentially, by altering its 3D structure. Only rabeprazole and omeprazole decreased trophozoite survival by inhibiting endogenous GlADI, while rabeprazole also decreased the Giardia encystment rate. These findings demonstrate the potential of GlADI as a target against giardiasis.

The impact of thiamine deficiency and benfotiamine treatment on Nod-like receptor protein-3 inflammasome in microglia

Thiamine-dependent processes are critical in cerebral glucose metabolism, it is abnormity induces oxidative stress, inflammation and neurodegeneration. Nod-like receptor protein-3 (NLRP3) inflammasome-mediated inflammation is closely related to neurologic diseases and can be activated by oxidative stress. However, the impact of thiamine deficiency on NLRP3 inflammasome activation remains unknown. In this study, we found that NLRP3 inflammasomes were significantly activated in the microglia of thiamine deficiency mice model. In contrast, benfotiamine dampened inflammation NLRP3 mediated in BV2 cells stimulated with LPS and ATP through reducing mitochondrial reactive oxygen species levels and mitigating autophagy flux defect. These data identify an important role of thiamine metabolism in NLRP3 inflammasome activation, and correcting thiamine metabolism through benfotiamine provides a new therapeutic strategy for NLRP3 inflammasome related neurological, metabolic, and inflammatory diseases.

Development of carbon dot-thiochrome-based sensing system for ratiometric fluorescence detection of D-penicillamine

A simple and rapid ratiometric fluorescent sensing system for D-penicillamine (D-PA) determination is developed based on yellow carbon dots (Y-CDs) combined with thiochrome (oxVB₁) for the first time. The oxidization of thiamine (VB₁) can be catalyzed by Alkaline-hydrolyzed artemisinin (a-ART) to form oxVB₁, which leads to the occurrence of fluorescence emission peak at 466 nm. Furthermore, the oxidation reaction between a-ART and VB₁ could be inhibited by D-PA, and accompanied with the decrease of fluorescence at 466 nm. However, the fluorescence peak of Y-CDs as an internal reference at 566 nm was almost unchanged. The ratiometric signal changes contributed to a robust and sensitive D-PA sensing. Under the optimal condition, a good linear response for the D-PA detection was obtained in the ranges of 0.5-50 μM with a detection limit of 0.33 μM. In addition, Y-CDs and thiochrome-based sensing system was applied to D-PA determination in real samples and obtained acceptable results. We developed a new carbon dots/thiochrome fluorescent nanoprobe for ratiometric fluorescence sensing of D-penicillamine.

Inverse agonism at the Na/K-ATPase receptor reverses EMT in prostate cancer cells

The surface expression of Na/K-ATPase α1 (NKA) is significantly reduced in primary prostate tumors and further decreased in bone metastatic lesions. Here, we show that the loss of cell surface expression of NKA induces epithelial-mesenchymal transition (EMT) and promotes metastatic potential and tumor growth of prostate cancer (PCa) by decreasing the expression of E-cadherin and increasing c-Myc expression via the activation of Src/FAK pathways. Mechanistically, reduced surface expression of NKA in PCa is due to increased endocytosis through the activation of NKA/Src receptor complex. Using a high-throughput NKA ligand-screening platform, we have discovered MB5 as an inverse agonist of the NKA/Src receptor complex, capable of blocking the endocytosis of NKA. MB5 treatment increased NKA expression and E-cadherin in PCa cells, which reversed EMT and consequently decreased the invasion and growth of spheroid models and tumor xenografts. Thus, we have identified a hitherto unrecognized mechanism that regulates EMT and invasiveness of PCa and demonstrated for the first time the feasibility of identifying inverse agonists of receptor NKA/Src complex and their potential utility as anticancer drugs. We, therefore, conclude that cell surface expression of α1 NKA can be targeted for the development of new therapeutics against aggressive PCa and that MB5 may serve as a prototype for drug development against EMT in metastatic PCa.

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.

Benfotiamine Reduces Dendritic Cell Inflammatory Potency

BACKGROUND

Benfotiamine is a synthetic liposoluble derivative of vitamin B1 that has been shown to have anti-inflammatory properties.

OBJECTIVE

To study the effects of benfotiamine on dendritic cells.

METHODS

Dendritic cells were obtained from murine bone marrow precursor cells in the presence of GM-CSF. Benfotiamine was applied to the cell culture during the process of bone marrow cell differentiation into dendritic cells. Dendritic cells were stimulated with lipopolysaccharide (LPS) and expression of MHC class II molecules and CD86 was determined by flow cytometry, while levels of tumor necrosis factor (TNF) and interleukin (IL)-1β in cell culture supernatants were measured by ELISA. F-Actin, NF-κB and Nrf2 were visualized by immunofluorescent staining and microscopy.

RESULTS

Benfotiamine potently reduced LPS-induced expression of MHC class II molecules and CD86, in addition to suppressing the release of pro-inflammatory cytokines TNF and IL-1β. It also prevented LPS-imposed morphological changes of dendritic cells, i.e. enlargement and intensified protrusions. The effects were paralleled with the reduction of NF-κB translocation to the nucleus, but not of Nrf2 activation inhibition.

CONCLUSION

Having in mind the importance of dendritic cells for the configuration of the immune response, our results imply that benfotiamine has the ability to regulate the immune response through inhibition of inflammatory properties of dendritic cells.

Allithiamine Exerts Therapeutic Effects on Sepsis by Modulating Metabolic Flux during Dendritic Cell Activation

Recent studies have highlighted that early enhancement of the glycolytic pathway is a mode of maintaining the pro-inflammatory status of immune cells. Thiamine, a well-known co-activator of pyruvate dehydrogenase complex, a gatekeeping enzyme, shifts energy utilization of glucose from glycolysis to oxidative phosphorylation. Thus, we hypothesized that thiamine may modulate inflammation by alleviating metabolic shifts during immune cell activation. First, using allithiamine, which showed the most potent anti-inflammatory capacity among thiamine derivatives, we confirmed the inhibitory effects of allithiamine on the lipopolysaccharide (LPS)-induced pro-inflammatory cytokine production and maturation process in dendritic cells. We applied the LPS-induced sepsis model to examine whether allithiamine has a protective role in hyper-inflammatory status. We observed that allithiamine attenuated tissue damage and organ dysfunction during endotoxemia, even when the treatment was given after the early cytokine release. We assessed the changes in glucose metabolites during LPS-induced dendritic cell activation and found that allithiamine significantly inhibited glucose-driven citrate accumulation. We then examined the clinical implication of regulating metabolites during sepsis by performing a tail bleeding assay upon allithiamine treatment, which expands its capacity to hamper the coagulation process. Finally, we confirmed that the role of allithiamine in metabolic regulation is critical in exerting anti-inflammatory action by demonstrating its inhibitory effect upon mitochondrial citrate transporter activity. In conclusion, thiamine could be used as an alternative approach for controlling the immune response in patients with sepsis.

Pain Bloc-R Alleviates Unresolved, Non-Pathological Aches and Discomfort in Healthy Adults—A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

The lack of effective treatment for chronic discomfort without negative side effects highlights the need for alternative treatments. Pain Bloc-R is a natural health product composed of vitamins B₆, B₁₂, D, white willow bark extract, Angelica root extract, acetyl L-carnitine HCl, caffeine, L-theanine, Benfotiamine, and L-tetrahydropalmatine. The objective of this study was to compare the effects of Pain Bloc-R, acetaminophen, and placebo on unresolved aches and discomfort as assessed by the brief pain inventory (BPI) and modified Cornell musculoskeletal discomfort questionnaires. This randomized, double-blind, placebo-controlled, crossover study consisted of three 7-day periods with Pain Bloc-R, acetaminophen, or placebo, each separated by a 7-day washout. Twenty-seven healthy adults (ages 22–63 years) were randomized to receive the three interventions in different sequences. The BPI “pain at its worst” scores were significantly lower when participants took Pain Bloc-R than when they took acetaminophen (21.8% vs. 9.8% decrease, p = 0.026) after seven days of supplementation. Pain Bloc-R achieved a significant improvement in the “pain at its least” score, significantly decreased the interference of discomfort in walking, and significantly decreased musculoskeletal discomfort total scores (34%, p = 0.040) after seven days. In a post hoc subgroup analysis based on age and gender, male participants ≤45 years taking Pain Bloc-R reported significant reductions in pain severity and pain interference vs. acetaminophen. Pain Bloc-R performed as well as acetaminophen in managing unresolved non-pathological pain in otherwise healthy individuals.

Beneficial effects of benfotiamine, a NADPH oxidase inhibitor, in isoproterenol-induced myocardial infarction in rats

BACKGROUND

Acute myocardial infarction (AMI) remains the most common cause of morbidity and mortality worldwide. The present study was directed to investigate the beneficial effects of benfotiamine pre- and post-treatments in isoproterenol (ISO)-induced MI in rats.

METHODS

Myocardial heart damage was induced by subcutaneous injection of ISO (150 mg/kg) once daily for two consecutive days. Benfotiamine (100 mg/kg/day) was given orally for two weeks before or after ISO treatment.

RESULTS

ISO administration revealed significant changes in electrocardiographic recordings, elevation of levels of cardiac enzymes; creatinine kinase (CK-MB) and troponin-I (cTn-I), and perturbation of markers of oxidative stress; nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and glutathione peroxidase (GPx) and markers of inflammation; protein kinase C (PKC), nuclear factor-kappa B (NF-κB) and metalloproteinase-9 (MMP-9). The apoptotic markers (caspase-8 and p53) were also significantly elevated in ISO groups in addition to histological alterations. Groups treated with benfotiamine pre- and post-ISO administration showed significantly decreased cardiac enzymes levels and improved oxidative stress, inflammatory and apoptotic markers compared to the ISO groups.

CONCLUSION

The current study highlights the potential role of benfotiamine as a promising agent for prophylactic and therapeutic interventions in myocardial damage in several cardiovascular disorders via NADPH oxidase inhibition.

Photolysis of thiochrome in aqueous solution: A kinetic study

The photolysis of thiochrome (THC), an oxidation product of thiamine (vitamin B₁) (THE), used for its fluorimetric assay, has been studied in the pH range 7.0-12.0. THC undergoes photooxidation to oxodihydrothiochrome (ODTHC) which is oxidized to a non-fluorescent compound (OP1) on UV irradiation. The kinetics of the consecutive first-order reactions: THC→k₁ODTHC→k₂OP1, has been evaluated and the values of first-order rate constants, k₁ (0.58-4.20 × 10^-5, s^-1) and k₂ (0.05-2.03 × 10^-5, s^-1), at pH 7.0-12.0 have been determined. The rates of degradation of THC and ODTHC are enhanced with pH and the second-order rate constants k₁' and k₂' for the OH^- ion-catalyzed reaction are in the range of 0.002-58.3 M^-1 s^-1. The quantum yields of the photolysis of THC and ODTHC in the pH range 7.0-12.0 have been determined. THC, ODTHC and OP1 have been identified by chromatographic, spectrometric and fluorimetric methods. THC and ODTHC have similar fluorescence characteristics and emit at 450 and 445 nm, respectively. THC, ODTHC and OP1 with distinct absorption maxima (370, 344 and 290 nm, respectively) have been determined by a newly developed and validated multicomponent spectrometric method during the photolysis reactions. The on-line formation of THC by the photooxidation of THE may lead to the degradation of THC and give erroneous results in the fluorimetric assay of THE. A scheme for the photolysis reactions of THC in aqueous solution is presented.

Benfotiamine and Cognitive Decline in Alzheimer's Disease: Results of a Randomized Placebo-Controlled Phase IIa Clinical Trial

BACKGROUND

In preclinical models, benfotiamine efficiently ameliorates the clinical and biological pathologies that define Alzheimer's disease (AD) including impaired cognition, amyloid-β plaques, neurofibrillary tangles, diminished glucose metabolism, oxidative stress, increased advanced glycation end products (AGE), and inflammation.

OBJECTIVE

To collect preliminary data on feasibility, safety, and efficacy in individuals with amnestic mild cognitive impairment (aMCI) or mild dementia due to AD in a placebo-controlled trial of benfotiamine.

METHODS

A twelve-month treatment with benfotiamine tested whether clinical decline would be delayed in the benfotiamine group compared to the placebo group. The primary clinical outcome was the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog). Secondary outcomes were the clinical dementia rating (CDR) score and fluorodeoxyglucose (FDG) uptake, measured with brain positron emission tomography (PET). Blood AGE were examined as an exploratory outcome.

RESULTS

Participants were treated with benfotiamine (34) or placebo (36). Benfotiamine treatment was safe. The increase in ADAS-Cog was 43% lower in the benfotiamine group than in the placebo group, indicating less cognitive decline, and this effect was nearly statistically significant (p = 0.125). Worsening in CDR was 77% lower (p = 0.034) in the benfotiamine group compared to the placebo group, and this effect was stronger in the APOEɛ4 non-carriers. Benfotiamine significantly reduced increases in AGE (p = 0.044), and this effect was stronger in the APOEɛ4 non-carriers. Exploratory analysis derivation of an FDG PET pattern score showed a treatment effect at one year (p = 0.002).

CONCLUSION

Oral benfotiamine is safe and potentially efficacious in improving cognitive outcomes among persons with MCI and mild AD.

A stage-specific cancer chemotherapy strategy through flexible combination of reduction-activated charge-conversional core-shell nanoparticles

Precision medicine has increased the demand for stage-specific cancer chemotherapy. Drugs with different properties are needed for different stages of tumor development, which is, inducing rapid destruction in the early stage and facilitating deep penetration in the advanced stage. Herein, we report a novel reduction-activated charge-conversional core-shell nanoparticle (CS NP) formula based on ring-closing metathesis of the thiamine disulfide system (TDS) to deliver the chemotherapeutic agent-gambogic acid (GA). Methods: The shell consisted of hyaluronic acid-all-trans retinoid acid with a disulfide bond as the linker (HA-SS-ATRA). The core was selected from poly (γ-glutamic acid) with different grafting rates of the functional group (Fx%) of TDS. GA/CF100%S NPs, with the strongest reduction-responsive drug release, and GA/CF60%S NPs with the strongest penetration have been finally screened. On this basis, a stage-specific administration strategy against a two-stage hepatocellular carcinoma was proposed. Results: The developed CS NPs have been confirmed as inducing reduction-activated charge conversion from about -25 to +30 mV with up to 95% drug release within 48 h. The administration strategy, GA/CF100%S NPs for the early-stage tumor, and sequential administration of GA/CF60%S NPs followed by GA/CF100%S NPs for the advanced-stage tumor, achieved excellent tumor inhibition rates of 93.86±2.94% and 90.76±6.43%, respectively. Conclusions: Our CS NPs provide a novel platform for charge conversion activated by reduction. The stage-specific administration strategy showed great promise for cancer therapy.

Benfotiamine treatment activates the Nrf2/ARE pathway and is neuroprotective in a transgenic mouse model of tauopathy

Impaired glucose metabolism, decreased levels of thiamine and its phosphate esters, and reduced activity of thiamine-dependent enzymes, such as pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and transketolase occur in Alzheimer's disease (AD). Thiamine deficiency exacerbates amyloid beta (Aβ) deposition, tau hyperphosphorylation and oxidative stress. Benfotiamine (BFT) rescued cognitive deficits and reduced Aβ burden in amyloid precursor protein (APP)/PS1 mice. In this study, we examined whether BFT confers neuroprotection against tau phosphorylation and the generation of neurofibrillary tangles (NFTs) in the P301S mouse model of tauopathy. Chronic dietary treatment with BFT increased lifespan, improved behavior, reduced glycated tau, decreased NFTs and prevented death of motor neurons. BFT administration significantly ameliorated mitochondrial dysfunction and attenuated oxidative damage and inflammation. We found that BFT and its metabolites (but not thiamine) trigger the expression of Nrf2/antioxidant response element (ARE)-dependent genes in mouse brain as well as in wild-type but not Nrf2-deficient fibroblasts. Active metabolites were more potent in activating the Nrf2 target genes than the parent molecule BFT. Docking studies showed that BFT and its metabolites (but not thiamine) bind to Keap1 with high affinity. These findings demonstrate that BFT activates the Nrf2/ARE pathway and is a promising therapeutic agent for the treatment of diseases with tau pathology, such as AD, frontotemporal dementia and progressive supranuclear palsy.

Amorphization of thiamine chloride hydrochloride: A study of the crystallization inhibitor properties of different polymers in thiamine chloride hydrochloride amorphous solid dispersions

Amorphous solid dispersions of thiamine chloride hydrochloride (THCl) were created using a variety of polymers with different physicochemical properties in order to investigate how effective the various polymers were as THCl crystallization inhibitors. THCl:polymer dispersions were prepared by lyophilizing solutions of THCl and amorphous polymers (guar gum, pectin, κ-carrageenan, gelatin, and polyvinylpyrrolidone (PVP)). These dispersions were stored at select temperature (25 and 40°C) and relative humidity (0, 23, 32, 54, 75, and 85% RH) conditions and monitored at different time points using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Moisture sorption isotherms of all samples were also obtained. Initially amorphous THCl was produced in the presence of ≥40% w/w pectin, κ-carrageenan, gelatin, and guar gum or ≥60% w/w PVP. Trends in polymer THCl crystallization inhibition (pectin≥κ-carrageenan>gelatin>guar gum≫PVP) were primarily based on the ability of the polymer to interact with THCl via hydrogen bonding and/or ionic interactions. The onset of THCl crystallization from the amorphous dispersions was also related to storage conditions. THCl remained amorphous at low RH conditions (0 and 23% RH) in all 1:1 dispersions except THCl:PVP. THCl crystallized in some dispersions below the glass transition temperature (T_g) but remained amorphous in others at T~T_g. At high RHs (75 and 85% RH), THCl crystallized within one day in all samples. Given the ease of THCl amorphization in the presence of a variety of polymers, even at higher vitamin concentrations than would be found in foods, it is likely that THCl is amorphous in many low moisture foods.

Arbuscular mycorrhiza improves yield and nutritional properties of onion (Allium cepa)

Improving the nutritional value of commonly cultivated crops is one of the most pending problems for modern agriculture. In natural environments plants associate with a multitude of fungal microorganisms that improve plant fitness. The best described group are arbuscular mycorrhizal fungi (AMF). These fungi have been previously shown to improve the quality and yield of several common crops. In this study we tested the potential utilization of Rhizophagus irregularis in accelerating growth and increasing the content of important dietary phytochemicals in onion (Allium cepa). Our results clearly indicate that biomass production, the abundance of vitamin B1 and its analogues and organic acid concentration can be improved by inoculating the plant with AM fungi. We have shown that improved growth is accompanied with up-regulated electron transport in PSII and antioxidant enzyme activity.

Pharmacokinetics of the transdermal delivery of benfotiamine

AIMS

Accumulation of advanced glycation endpoints is a trigger to the development of diabetic peripheral neuropathy, which is a common complication of diabetes. Oral administration of benfotiamine (BFT) has shown some preclinical and clinical promise as a treatment for diabetic peripheral neuropathy. The purpose of this study was to evaluate the method of transdermal delivery of BFT as a possible, viable route of administration for the treatment of diabetic peripheral neuropathy.

METHODS

A single application of 10 mg of BFT was given to guinea pigs topically. The levels of thiamine (T), thiamine monophosphate, thiamine diphosphate, S-benzoylthiamine and BFT were measured in the blood, skin and muscle at different time points within 24 h.

RESULTS

At the 24-h time point, following the single BFT dose, the T level was increased 10× in the blood, more than 7× in the skin and almost 4× in the muscle compared to the untreated animals. The total T content (total) was increased 7× in the blood, 17× in the skin and 3× in the muscle compared to the untreated animals.

CONCLUSIONS

This strong increase in the tissue levels of T and the associated metabolic derivatives levels found in the blood and local tissues following a single dose indicate that topically applied BFT may be a viable and advantageous delivery method for the treatment of diabetic peripheral neuropathy.

Stability-Indicating HPTLC Method for Studying Stress Degradation Behavior of Sulbutiamine HCl

Sulbutiamine (SUL) is an ester of thiazides with neurotropic action. A new stability indicating HPTLC method has been developed and validated for the determination of SUL in the presence of different degradation products. The drug was subjected to different stress conditions following ICH strategy such as hydrolytic degradation (neutral, alkaline and acidic hydrolysis), oxidation, photodegradation and dry heat degradation. The drug demonstrated degradation under all decomposition conditions except neutral hydrolysis and dry heat, where the drug was completely degraded with 0.1 N NaOH, 1 N HCl and 30% H2O2 while it was partially degradaed by 0.1 N HCl, 3% H2O2 and UV light. Structure elucidation of the resulting degradation products was performed using ESI-Q-MS-MS. A well-defined peak for SUL was obtained at Rf = 0.46 and was completely separated from all obtained degradation products. Chromatographic separation was carried out on HPTLC aluminum plates precoated with silica gel 60 F254 using acetone-methylene chloride-ammonia buffer (pH 8.5 ± 0.2) (7:3:0.5, v/v) as a developing system. Densitometric scanning of the separated peaks was performed at 254 nm. System suitability testing parameters were calculated to ascertain the quality performance of the developed method. The method was validated with respect to USP guidelines regarding accuracy, precision, specificity, robustness and ruggedness. Good correlation coefficients were achieved in the range of 0.4-5.0 µg/band, and the limit of detection and limit of quantitation were found to be 0.11 and 0.33 µg/band, respectively. The utility of the suggested method was verified by application to Arcalion forte® tablets where no interference from additives was found.

[Clinical and MRI Findings in Patients with Congenital Anosmia]

The clinical characteristics of 16 patients with congenital anosmia were examined retrospectively. MRI (magnetic resonance imaging) was used to assess the morphological changes in the olfactory bulbs and olfactory sulci according to the method of P. Rombaux (2009). Congenital anosmia was divided into two forms: syndromic forms in association with a syndrome, and isolated forms without evidence of other defects. Only three patients (19%) in our series had syndromic forms of congenital anosmia, such as the Kallmann syndrome. Most cases (13 patients, 81%) had isolated congenital anosmia. Psychophysical testing of the olfactory function included T&T olfactometry and the intravenous Alinamin test, which are widely used in Japan. In T&T olfactometry, detection and recognition thresholds for the five odorants are used to assign a diagnostic category representing the level of olfactory function. Most cases (14 patients, 88%) showed off-scale results on T&T olfactometry, and the Alinamin test resulted in no response in all 11 patients who underwent the test. Abnormal MRI findings of the olfactory bulbs and sulci were detected in 15 of 16 patients (94%). Olfactory bulbs were bilaterally absent in nine patients (56%), and two patients (13%) had unilateral olfactory bulbs. Four patients (25%) had bilateral hypoplastic olfactory bulbs, and only one patient had normal olfactory bulbs (6%). The olfactory sulcus was unilaterally absent in one patient (6%), and nine patients (56%) had bilaterally hypoplastic olfactory sulci. Two patients (13%) had a unilateral normal olfactory sulcus and hypoplastic olfactory sulcus. Three patients (19%) had normal olfactory sulci. Quantitative analysis showed that the volume of olfactory bulbs varied from 0 mm3 to 63.5 mm3, with a mean volume of 10.20 ± 18 mm3, and the mean depth of the olfactory sulcus varied from 0 mm to 12.22 mm, with a mean length of 4.85 ± 4.1 mm. Currently, there is no effective treatment for congenital anosmia. However, diagnosis of congenital anosmia is important, as its presence can lead to dangerous situations. Careful examination for hypogonadism is also required in people with anosmia. MRI examinations of the olfactory bulbs and sulci were useful for the diagnosis of congenital anosmia.

Paraptosis cell death induction by the thiamine analog benfotiamine in leukemia cells

Benfotiamine is a synthetic thiamine analogue that stimulates transketolase, a cellular enzyme essential for glucose metabolism. Currently, benfotiamine is used to treat diabetic neuropathy. We recently reported that oral benfotiamine induced a temporary but remarkable recovery from acute myeloid leukemia in an elderly patient who was ineligible for standard chemotherapy due to dementia and renal failure. In the present study we present evidences that benfotiamine possess antitumor activity against leukemia cells. In a panel of nine myeloid leukemia cell lines benfotiamine impaired the viability of HL-60, NB4, K562 and KG1 cells and also inhibited the growing of primary leukemic blasts. The antitumor activity of benfotiamine is not mediated by apoptosis, necrosis or autophagy, but rather occurs though paraptosis cell death induction. Mechanistic studies revealed that benfotiamine inhibited the activity of constitutively active ERK1/2 and concomitantly increased the phosphorylation of JNK1/2 kinase in leukemic cells. In addition, benfotiamine induced the down regulation of the cell cycle regulator CDK3 which resulted in G1 cell cycle arrest in the sensitive leukemic cells. Moreover, combination index studies showed that benfotiamine enhanced the antiproliferative activities of cytarabine against leukemia cells. These findings suggest that benfotiamine has antitumor therapeutic potential.

A novel spectral resolution and simultaneous determination of multicomponent mixture of Vitamins B1, B6, B12, Benfotiamine and Diclofenac in tablets and capsules by derivative and MCR-ALS

A novel method was developed for spectral resolution and further determination of five-component mixture including Vitamin B complex (B1, B6, B12 and Benfotiamine) along with the commonly co-formulated Diclofenac. The method is simple, sensitive, precise and could efficiently determine the five components by a complementary application of two different techniques. The first is univariate second derivative method that was successfully applied for determination of Vitamin B12. The second is Multivariate Curve Resolution using the Alternating Least Squares method (MCR-ALS) by which an efficient resolution and quantitation of the quaternary spectrally overlapped Vitamin B1, Vitamin B6, Benfotiamine and Diclofenac sodium were achieved. The effect of different constraints was studied and the correlation between the true spectra and the estimated spectral profiles were found to be 0.9998, 0.9983, 0.9993 and 0.9933 for B1, B6, Benfotiamine and Diclofenac, respectively. All components were successfully determined in tablets and capsules and the results were compared to HPLC methods and they were found to be statistically non-significant.

Benfotiamine attenuates inflammatory response in LPS stimulated BV-2 microglia

Microglial cells are resident immune cells of the central nervous system (CNS), recognized as key elements in the regulation of neural homeostasis and the response to injury and repair. As excessive activation of microglia may lead to neurodegeneration, therapeutic strategies targeting its inhibition were shown to improve treatment of most neurodegenerative diseases. Benfotiamine is a synthetic vitamin B1 (thiamine) derivate exerting potentially anti-inflammatory effects. Despite the encouraging results regarding benfotiamine potential to alleviate diabetic microangiopathy, neuropathy and other oxidative stress-induced pathological conditions, its activities and cellular mechanisms during microglial activation have yet to be elucidated. In the present study, the anti-inflammatory effects of benfotiamine were investigated in lipopolysaccharide (LPS)-stimulated murine BV-2 microglia. We determined that benfotiamine remodels activated microglia to acquire the shape that is characteristic of non-stimulated BV-2 cells. In addition, benfotiamine significantly decreased production of pro-inflammatory mediators such as inducible form of nitric oxide synthase (iNOS) and NO; cyclooxygenase-2 (COX-2), heat-shock protein 70 (Hsp70), tumor necrosis factor alpha α (TNF-α), interleukin-6 (IL-6), whereas it increased anti-inflammatory interleukin-10 (IL-10) production in LPS stimulated BV-2 microglia. Moreover, benfotiamine suppressed the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK) and protein kinase B Akt/PKB. Treatment with specific inhibitors revealed that benfotiamine-mediated suppression of NO production was via JNK1/2 and Akt pathway, while the cytokine suppression includes ERK1/2, JNK1/2 and Akt pathways. Finally, the potentially protective effect is mediated by the suppression of translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the nucleus. Therefore, benfotiamine may have therapeutic potential for neurodegenerative diseases by inhibiting inflammatory mediators and enhancing anti-inflammatory factor production in activated microglia.

Vitamin B and its derivatives for diabetic kidney disease

BACKGROUND

Diabetes is a leading cause of end-stage kidney disease (ESKD) mainly due to development and progression of diabetic kidney disease (DKD). In absence of definitive treatments of DKD, small studies showed that vitamin B may help in delaying progression of DKD by inhibiting vascular inflammation and endothelial cell damage. Hence, it could be beneficial as a treatment option for DKD.

OBJECTIVES

To assess the benefits and harms of vitamin B and its derivatives in patients with DKD.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 29 October 2012 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials comparing vitamin B or its derivatives, or both with placebo, no treatment or active treatment in patients with DKD. We excluded studies comparing vitamin B or its derivatives, or both among patients with pre-existing ESKD.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias and extracted data. Results were reported as risk ratio (RR) or risk differences (RD) with 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) with 95% CI for continuous outcomes. Statistical analyses were performed using the random-effects model.

MAIN RESULTS

Nine studies compared 1354 participants randomised to either vitamin B or its derivatives with placebo or active control were identified. A total of 1102 participants were randomised to single vitamin B derivatives, placebo or active control in eight studies, and 252 participants randomised to multiple vitamin B derivatives or placebo. Monotherapy included different dose of pyridoxamine (four studies), benfotiamine (1), folic acid (1), thiamine (1), and vitamin B12 (1) while combination therapy included folic acid, vitamin B6, and vitamin B12 in one study. Treatment duration ranged from two to 36 months. Selection bias was unclear in three studies and low in the remaining six studies. Two studies reported blinding of patient, caregiver and observer and were at low risk of performance and detection bias, two studies were at high risk bias, and five studies were unclear. Attrition bias was high in one study, unclear in one study and low in seven studies. Reporting bias was high in one study, unclear in one study, and low in the remaining seven studies. Four studies funded by pharmaceutical companies were judged to be at high risk bias, three were at low risk of bias, and two were unclear.Only a single study reported a reduction in albuminuria with thiamine compared to placebo, while second study reported reduction in glomerular filtration rate (GFR) following use of combination therapy. No significant difference in the risk of all-cause mortality with pyridoxamine or combination therapy was reported. None of the vitamin B derivatives used either alone or in combination improved kidney function: increased in creatinine clearance, improved the GFR; neither were effective in controlling blood pressure significantly compared to placebo or active control. One study reported a significant median reduction in urinary albumin excretion with thiamine treatment compared to placebo. No significant difference was found between vitamin B combination therapy and control group for serious adverse events, or one or more adverse event per patient. Vitamin B therapy was reported to well-tolerated with mild side effects in studies with treatment duration of more than six months. Studies of less than six months duration did not explicitly report adverse events; they reported that the drugs were well-tolerated without any serious drug related adverse events. None of the included studies reported cardiovascular death, progression from macroalbuminuria to ESKD, progression from microalbuminuria to macroalbuminuria, regression from microalbuminuria to normoalbuminuria, doubling of SCr, and quality of life. We were not able to perform subgroup or sensitivity analyses or assess publication bias due to insufficient data.

AUTHORS' CONCLUSIONS

There is an absence of evidence to recommend the use of vitamin B therapy alone or combination for delaying progression of DKD. Thiamine was found to be beneficial for reduction in albuminuria in a single study; however, there was lack of any improvement in kidney function or blood pressure following the use of vitamin B preparations used alone or in combination. These findings require further confirmation given the limitations of the small number and poor quality of the available studies.

[Extracting and study of biochemical properties of thiamine pyrophosphokinase from non-malignant and tumor tissue of myometrium]

The method of extraction and purification of thiamine pyrophosphokinase from non-malignant and tumor tissue of myometrium has been elaborated. Kinetic characteristics of T-kinase from non-malignant and tumor tissue of women myometrium have been studied. It has been shown, that malignization of myometrium is accompanied by a decrease in affinity of thiamine pyrophosphokinase from tumor to thiamine and by an increase in sensitivity of the enzyme from tumor to thiochrome.

Annexin V imaging detects diabetes-accelerated apoptosis and monitors the efficacy of benfotiamine treatment in ischemic limbs of mice

The role of apoptosis imaging for monitoring treatment response in ischemic limbs has not been properly explored. In this study, we investigated the ability of annexin V (AnxV) imaging to assess the efficacy of antiapoptotic treatment in ischemic limbs of diabetic mice. Normal C57BL/6 mice and streptozotocin-induced diabetic mice were subject to hindlimb ischemia. AnxV-conjugated fluorescent streptavidin probes were intravenously injected, and optical imaging was performed. Tissue apoptosis was quantified by histochemistry and Western blotting. The AnxV probes showed specific targeting to apoptotic cells on confocal microscopy and flow cytometry. Intravenous AnxV probes displayed substantially greater accumulation in ischemic limbs of diabetic mice. Benfotiamine (BFT) treatment of diabetic mice led to better perfusion recovery on laser Doppler imaging and reduced AnxV binding on optical imaging. TUNEL staining and cleaved caspase-3 Western blots confirmed accelerated apoptosis by diabetes and its suppression by BFT treatment. Furthermore, AnxV-SAv-PEcy5.5 uptake in the ischemic limbs closely correlated to cleaved caspase-3 expression. Thus, AnxV imaging may be useful for monitoring the efficacy of therapeutic agents designed to suppress ischemia-induced apoptosis.

A randomized, double-blind, crossover, placebo-controlled trial of 6 weeks benfotiamine treatment on postprandial vascular function and variables of autonomic nerve function in Type 2 diabetes

AIMS

In a pilot study we suggested that benfotiamine, a thiamine prodrug, prevents postprandial endothelial dysfunction in people with Type 2 diabetes mellitus. The aim of this study was to test these effects in a larger population.

METHODS

In a double-blind, placebo-controlled, randomized, crossover study, 31 people with Type 2 diabetes received 900 mg/day benfotiamine or a placebo for 6 weeks (with a washout period of 6 weeks between). At the end of each treatment period, macrovascular and microvascular function were assessed, together with variables of autonomic nervous function in a fasting state, as well as 2, 4 and 6 h following a heated, mixed test meal.

RESULTS

Participants had an impaired baseline flow-mediated dilatation (2.63 ± 2.49%). Compared with the fasting state, neither variable changed postprandially following the placebo treatment. The 6 weeks' treatment with high doses of benfotiamine did not alter this pattern, either in the fasting state or postprandially. Among a subgroup of patients with the highest flow-mediated dilatation, following placebo treatment there was a significant postprandial flow-mediated dilatation decrease, while this effect was attenuated by benfotiamine pretreatment.

CONCLUSIONS

In people with Type 2 diabetes and markedly impaired fasting flow-mediated dilatation, a mixed test meal does not further deteriorate flow-mediated dilatation or variables of microvascular or autonomic nervous function. Because no significant deterioration of postprandial flow-mediated dilatation, microvascular or autonomic nervous function tests occurred after placebo treatment, a prevention of the postprandial deterioration of these variables with benfotiamine was not feasible.

Variability of skin autofluorescence measurement over 6 and 12 weeks and the influence of benfotiamine treatment

BACKGROUND

Measurements of skin autofluorescence (SAF) allow for a simple and noninvasive quantification of tissue advanced glycation end-products (AGEs), a marker linked to the risk of diabetes complications. The aim of this study was to test the repeatability of SAF over 6 and 12 weeks and to test whether benfotiamine, a thiamine prodrug suggested to reduce AGEs formation under hyperglycemic conditions, is able to attenuate SAF when administered over 6 weeks.

PATIENTS AND METHODS

In a double-blind, placebo-controlled, randomized, crossover study, 22 patients with type 2 diabetes mellitus (T2DM) received 900 mg/day benfotiamine or placebo for 6 weeks (washout period of 6 weeks between). At the beginning and at the end of each treatment period, SAF was assessed in the fasting state, as well as 2, 4, and 6 h following a mixed test meal.

RESULTS

The respective intra-individual and inter-individual variability of fasting SAF was 6.9% and 24.5% within 6 weeks and 10.9% and 23.1% within 12 weeks. The respective variability calculated for triplicate comparisons was 9.9% and 27.7%. A short-term therapy with benfotiamine did not influence SAF significantly, nor did we find a significant postprandial SAF increase.

CONCLUSIONS

In patients with T2DM, repeated, timely spaced SAF measurements have an intra-subject variability of below 11%. Using these data, sample sizes were calculated for interventional studies aiming at reducing SAF. Benfotiamine treatment for 6 weeks did not significantly influence SAF; for this, a longer-term therapy is probably needed.

Current therapeutic interventions in the glycation pathway: evidence from clinical studies

The increased formation of advanced glycation endproducts (AGEs) constitutes a potential mechanism of hyperglycaemia-induced micro- and macrovascular disease in diabetes. In vitro and animal experiments have shown that various interventions can inhibit formation and/or actions of AGEs, in particular the specific AGE inhibitor aminoguanidine and the AGEs crosslink breaker alagebrium, and the B vitamins pyridoxamine and thiamine, and the latter's synthetic derivative, benfotiamine. The potential clinical value of these interventions, however, remains to be established. The present review provides, from the clinical point of view, an overview of current evidence on interventions in the glycation pathway relating to (i) the clinical benefits of specific AGE inhibitors and AGE breakers and (ii) the potential AGE-inhibiting effects of therapies developed for purposes unrelated to the glycation pathway. We found that safety and/or efficacy in clinical studies with the specific AGE inhibitor, aminoguanidine and the AGE breaker, alagebrium, appeared to be a concern. The clinical evidence on the potential AGE-inhibiting effects of B vitamins is still limited. Finally, current evidence for AGE inhibition by therapies developed for purposes unrelated to glycation is limited due to a large heterogeneity in study designs and/or measurement techniques, which have often been sub-optimal. We conclude that, clinical evidence on interventions to inhibit formation and/or action of AGEs is currently weak and unconvincing.

Benfotiamine enhances antioxidant defenses and protects against cisplatin-induced DNA damage in nephrotoxic rats

The objective of the present study was to assess superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), paraoxonase (PON1), glutathione reductase (GR), and catalase (CAT) activities ratio and their relationship with DNA oxidative damage in rats treated with cisplatin (3 mg/kg bwt/day) in the presence and absence of benfotiamine (100 mg/kg/day) for 25 days. Cisplatin-induced renal damage was evidenced by renal dysfunction and elevated oxidative stress markers. SOD activity and levels of nitric oxide, protein carbonyl, malondialdehyde, and 8-hydroxy-2'-deoxyguanosine were significantly increased by cisplatin treatment. Moreover, the ratios of GPx/GR, SOD/GPx, SOD/CAT, and SOD/PON1 were significantly increased compared to control. In contrast, glutathione levels were significantly decreased by cisplatin treatment. Simultaneous treatment of rats with cisplatin and benfotiamine ameliorate these variables to values near to those of control rats. This study suggests that benfotiamine can prevent cisplatin-induced nephrotoxicity by inhibiting formation reactive species of oxygen and nitrogen.

Boosting the pentose phosphate pathway restores cardiac progenitor cell availability in diabetes

AIMS

Diabetes impinges upon mechanisms of cardiovascular repair. However, the biochemical adaptation of cardiac stem cells to sustained hyperglycaemia remains largely unknown. Here, we investigate the molecular targets of high glucose-induced damage in cardiac progenitor cells (CPCs) from murine and human hearts and attempt safeguarding CPC viability and function through reactivation of the pentose phosphate pathway.

METHODS AND RESULTS

Type-1 diabetes was induced by streptozotocin. CPC abundance was determined by flow cytometry. Proliferating CPCs were identified in situ by immunostaining for the proliferation marker Ki67. Diabetic hearts showed marked reduction in CPC abundance and proliferation when compared with controls. Moreover, Sca-1(pos) CPCs isolated from hearts of diabetic mice displayed reduced activity of key enzymes of the pentose phosphate pathway, glucose-6-phosphate dehydrogenase (G6PD), and transketolase, increased levels of superoxide and advanced glucose end-products (AGE), and inhibition of the Akt/Pim-1/Bcl-2 signalling pathway. Similarly, culture of murine CPCs or human CD105(pos) progenitor cells in high glucose inhibits the pentose phosphate and pro-survival signalling pathways, leading to the activation of apoptosis. In vivo and in vitro supplementation with benfotiamine reactivates the pentose phosphate pathway and rescues CPC availability and function. This benefit is abrogated by either G6PD silencing by small interfering RNA (siRNA) or Akt inhibition by dominant-negative Akt.

CONCLUSION

We provide new evidence of the negative impact of diabetes and high glucose on mechanisms controlling CPC redox state and survival. Boosting the pentose phosphate pathway might represent a novel mechanistic target for protection of CPC integrity.

[The effect of long-chain polyunsaturated higher ω-3 fatty acids, benfotiamine and α-lipoic acid on the lipid metabolism in patients with diabetes mellitus type 2 and cardiovascular autonomic neuropathy]

Eighty-one patients with diabetes mellitus type 2 (DM) and cardiovascular autonomic neuropathy were studied. The combined treatment with ω-3 PUFA, benfotiamine, and α-lipoic acid resulted in significant positive changes in total cholesterol, triacylglycerol, LDL and HDL cholesterol levels. The efficacy of this treatment was not associated with the improved compensation of DM but was a result of the direct influence of pharmacological agents on the metabolic rate studied.

Human pericyte-endothelial cell interactions in co-culture models mimicking the diabetic retinal microvascular environment

Pericytes regulate vascular tone, perfusion pressure and endothelial cell (EC) proliferation in capillaries. Thiamine and benfotiamine counteract high glucose-induced damage in vascular cells. We standardized two human retinal pericyte (HRP)/EC co-culture models to mimic the diabetic retinal microvascular environment. We aimed at evaluating the interactions between co-cultured HRP and EC in terms of proliferation/apoptosis and the possible protective role of thiamine and benfotiamine against high glucose-induced damage. EC and HRP were co-cultured in physiological glucose and stable or intermittent high glucose, with or without thiamine/benfotiamine. No-contact model: EC were plated on a porous membrane suspended into the medium and HRP on the bottom of the same well. Cell-to-cell contact model: EC and HRP were plated on the opposite sides of the same membrane. Proliferation (cell counts and DNA synthesis), apoptosis and tubule formation in Matrigel were assessed. In the no-contact model, stable high glucose reduced proliferation of co-cultured EC/HRP and EC alone and increased co-cultured EC/HRP apoptosis. In the contact model, both stable and intermittent high glucose reduced co-cultured EC/HRP proliferation and increased apoptosis. Stable high glucose had no effects on HRP in separate cultures. Both EC and HRP proliferated better when co-cultured. Thiamine and benfotiamine reversed high glucose-induced damage in all cases. HRP are sensitive to soluble factors released by EC when cultured in high glucose conditions, as suggested by conditioned media assays. In the Matrigel models, addition of thiamine and benfotiamine re-established the high glucose-damaged interactions between EC/HRP and stabilized microtubules.

[Oxidized derivatives of thiamine: formation, properties, biological role]

The data available in literature about formation, properties, possible biological role and practical application of the oxidized derivatives of B1 vitamin (thiamine) is first generalized and analysed in the review. It is known that at the values of pH > 7.0 the molecule of thiamine is able to undergo two-phase reaction of opening of thiazole ring with formation of anion of thiol form of thiamine and unstable tricyclic form. In the presence of oxidants in an alkaline environment a thiol form of thiamine is oxidized to thiamine disulfide, tricyclic form--to thiochrome. Oxidative transformation of thiamine molecule is promoted by phenoxyl radicals, their level can be substantially increased in animal tissues at oxidizing stress of different origin when the level of reactive forms of oxygen sharply increases and content of hemoproteins oxoferryl forms is raised. The analysis of literature data gives grounds to assume that thiamine and its hydrophobic metabolite--thiochrome--under certain conditions can perform an important antioxidant function in protection of cell structures against damaging action of peroxinitrite, nitrogen dioxide, peroxide. The presence of oxidized metabolites of thiamine and its phosphates in the cells of animals, even in minor quantities, is an established fact and, consequently, there is a possibility, that they can interact specifically with cellular structures or proteins to effect cellular processes in certain conditions.

Prostatic acid phosphatase is required for the antinociceptive effects of thiamine and benfotiamine

Thiamine (Vitamin B1) is an essential vitamin that must be obtained from the diet for proper neurological function. At higher doses, thiamine and benfotiamine (S-benzoylthiamine O-monophosphate, BT)–a phosphorylated derivative of thiamine–have antinociceptive effects in animals and humans, although how these compounds inhibit pain is unknown. Here, we found that Prostatic acid phosphatase (PAP, ACPP) can dephosphorylate BT in vitro, in dorsal root ganglia (DRG) neurons and in primary-afferent axon terminals in the dorsal spinal cord. The dephosphorylated product S-benzoylthiamine (S-BT) then decomposes to O-benzoylthiamine (O-BT) and to thiamine in a pH-dependent manner, independent of additional enzymes. This unique reaction mechanism reveals that BT only requires a phosphatase for conversion to thiamine. However, we found that the antinociceptive effects of BT, thiamine monophosphate (TMP) and thiamine–a compound that is not phosphorylated–were entirely dependent on PAP at the spinal level. Moreover, pharmacokinetic studies with wild-type and Pap^−/− mice revealed that PAP is not required for the conversion of BT to thiamine in vivo. Taken together, our study highlights an obligatory role for PAP in the antinociceptive effects of thiamine and phosphorylated thiamine analogs, and suggests a novel phosphatase-independent function for PAP.

Antiglycation activity of thiamin-HCl and benfotiamine in diabetic condition

OBJECTIVE

To observe the antiglycation effect of water-soluble vitamin, thiamin-hydrochloride (B1) and its fat-soluble derivative benfotiamine and their comparison with two different glycation assays in diabetics.

METHODS

Plasma of both the normal's and diabetic persons was taken for this experimental study which was conducted in the Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad in 2008. Varying concentrations of both the glycation inhibitors and glucose were incubated for 5 weeks at 37 degrees C. Thiobarbituric acid and periodate borohydride assays were used to measure the antiglycation activity.

RESULTS

The increase in glycation was observed from 1st to 3rd week of incubation, while it decreased after the 5th week due to the formation of advanced glycation end products.

CONCLUSIONS

It was observed that 10mM concentration of benfotiamine and 5mM and 1mM concentrations of thiamine-hydrochloride produced fairly good response to decreased glycation. Comparison between two assays proved periodate borohydride to be more reliable and sensitive than thiobarbituric acid.

[The importance of the pharmaceutical form and the routes of administration of B-group vitamins for the efficacious treatment of neurosensorial hearing loss]

The objective of the present comparative study was to estimate the efficacy of the treatment of neurosensorial hearing loss (NSHL) with the use of milgamma, milgamma compositum, and vitamins B1 and B2 monotherapy. The best results were obtained after the treatment with milgamma and milgamma compositum. It is concluded that the use of these preparations for the combined treatment of neurosensorial hearing loss is pathogenetically justified since it permits to achieve the improvement of the functional state of the cochleovestibular nerve and the enhancement of patient compliance; moreover, it reduces the work load on the medical personnel.

Anti-inflammatory effects of benfotiamine are mediated through the regulation of the arachidonic acid pathway in macrophages

Benfotiamine, a lipid-soluble analogue of vitamin B1, is a potent antioxidant that is used as a food supplement for the treatment of diabetic complications. Our recent study (U.C. Yadav et al., Free Radic. Biol. Med. 48:1423-1434, 2010) indicates a novel role for benfotiamine in the prevention of bacterial endotoxin, lipopolysaccharide (LPS)-induced cytotoxicity and inflammatory response in murine macrophages. Nevertheless, it remains unclear how benfotiamine mediates anti-inflammatory effects. In this study, we investigated the anti-inflammatory role of benfotiamine in regulating arachidonic acid (AA) pathway-generated inflammatory lipid mediators in RAW264.7 macrophages. Benfotiamine prevented the LPS-induced activation of cPLA2 and release of AA metabolites such as leukotrienes, prostaglandin E2, thromboxane 2 (TXB2), and prostacyclin (PGI2) in macrophages. Further, LPS-induced expression of AA-metabolizing enzymes such as COX-2, LOX-5, TXB synthase, and PGI2 synthase was significantly blocked by benfotiamine. Furthermore, benfotiamine prevented the LPS-induced phosphorylation of ERK1/2 and expression of transcription factors NF-κB and Egr-1. Benfotiamine also prevented the LPS-induced oxidative stress and protein-HNE adduct formation. Most importantly, compared to specific COX-2 and LOX-5 inhibitors, benfotiamine significantly prevented LPS-induced macrophage death and monocyte adhesion to endothelial cells. Thus, our studies indicate that the dual regulation of the COX and LOX pathways in AA metabolism could be a novel mechanism by which benfotiamine exhibits its potential anti-inflammatory response.

[The role of neurotropic therapy in the treatment of acute sensorineural impairment of hearing following a viral infection]

The objective of the study. To estimate the efficacy of consecutive prescription of combined neurotropic therapy in addition to conventional treatment modalities for the patients presenting with acute sensorineural impairment of hearing. The results of analysis of the examination and treatment of 58 patients presenting with acute sensorineural impairment of hearing following a viral infection are presented. The patients of the study group (group 1) received the treatment according to the following scheme: intramuscular injections of milgamma at a dose of 2 ml for 10 days followed by the intake of milgamma tablets thrice daily during 20 days. The control patients (group 2) was comprised of the patients given conventional therapy alone. The efficacy of the treatment was estimated based on the results of tonal threshold audiometry before and after the treatment. It was shown that neurotropic therapy can speed up the process of hearing recovery in the patients suffering its acute sensorineural impairment by at least 5 days. The efficacy of traditional treatment combined with milgamma therapy in the patients with acute sensorineural impairment of hearing of allegedly viral etiology proved to be higher than that of conventional therapy alone within the first days after the onset of the treatment.

Thiamin(e): the spark of life

One of the earliest vitamins to be discovered and synthesized, thiamin was originally spelled with an "e". The terminal "e" was dropped when it was found that it was not an amine. It is still spelled with and without the "e" depending on the text. This chapter provides a brief historical review of the association of thiamin with the ancient scourge of beriberi. It emphasizes that beriberi is the model for high calorie malnutrition because of its occurrence in predominantly white rice consuming cultures. Some of the symptomatology of this ancient scourge is described, emphasizing the difference from that seen in starvation. High calorie malnutrition, due to excessive ingestion of simple carbohydrates, is widely encountered in the U.S.A. today. Thiamin deficiency is commonly associated with this, largely because of its cofactor status in the metabolism of glucose. The biochemistry of the three phosphorylated esters of thiamin and the transporters are discussed and the pathophysiology of thiamin deficiency reviewed. The role of thiamin, and particularly its synthetic derivatives as therapeutic agents, is not fully appreciated in Western civilization and a clinical section describes some of the unusual cases described in the scientific literature and some experienced by the author. The possible role of high calorie malnutrition and related thiamin deficiency in juvenile crime is hypothesized.

[Neuropathy pain: tactic of treatment]

Diagnostics of neuropathy pain is presented in the article, where most essential are methods of clinical estimation with the use of questionnaires and scales for verification and quantitative estimation of pain. The neurological inspection of patients with suspicion on neuropathy pain must plug in itself of the motive, sensory and vegetative phenomena with the purpose of authentication of all signs of neurological dysfunction. If on a background immunotherapy it is not succeeded fully a pain syndrome preparations of the first row, setting of combined pharmacotherapy allows to promote efficiency of treatment at the less dosages of preparations and reduce the risk of development of by-effects.

[A relationship between analgesic and neurotropic effects by the example of milgamma]

Combined vitamin preparations containing thiamine (vitamin B1), pyridoxine (vitamin B6), and cyanocobalamin (vitamin B12) are widely used in medical practice. The results of investigations have confirmed that it is expedient to potentiate an analgesic effect due to the concurrent use of vitamin B group and nonsteroidal anti-inflammatory drugs given to relieve significant neuropathic pain. Milgamma compositum (Wörwag Pharma, Germany) is one of the most studied drugs on the Russian market, which contains a combination of vitamin B group (including benfotiamin).

[Cochleovestibular disorders: approaches to diagnostics and treatment]

The aim of this work was to evaluate the efficacy of introduction of milgamma and milgamma compositum in the treatment of 52 patients with cochleovestibular disorders of different etiology. Thirteen patients enrolled in the study received standard therapy and 39 others were given its combination with milgamma preparations. Combined therapy with milgamma and milgamma compositum ensured faster vestibular compensation including posturographic characteristics than the standard treatment (within 3-4 weeks compared with 5 weeks in controls). The results of the study give reason to recommend milgamma and milgamma compositum as neurotropic medicines in addition to standard therapy for the management of the patients presenting with cochleovestibular disorders for the acceleration of the vestibular compensation.

[Sensorineural hearing loss: New prospects for therapy]

The authors developed a pathogenetically sound rationale for the estimation of the therapeutic efficacy of milgamma and milgamma compositum used to treat patients presenting with neurosensory loss of hearing. The results of relevant studies are presented. It is concluded that the inclusion of these preparations in the combined treatment of patients with acute and progredient forms of chronic neurosensory deafness creates conditions for the stable positive clinical effect.

Sulbutiamine counteracts trophic factor deprivation induced apoptotic cell death in transformed retinal ganglion cells

Sulbutiamine is a highly lipid soluble synthetic analogue of vitamin B(1) and is used clinically for the treatment of asthenia. The aim of our study was to demonstrate whether sulbutiamine is able to attenuate trophic factor deprivation induced cell death to transformed retinal ganglion cells (RGC-5). Cells were subjected to serum deprivation for defined periods and sulbutiamine at different concentrations was added to the cultures. Various procedures (e.g. cell viability assays, apoptosis assay, reactive oxygen species analysis, Western blot analysis, flow cytometric analysis, glutathione (GSH) and glutathione-S-transferase (GST) measurement) were used to demonstrate the effect of sulbutiamine. Sulbutiamine dose-dependently attenuated apoptotic cell death induced by serum deprivation and stimulated GSH and GST activity. Moreover, sulbutiamine decreased the expression of cleaved caspase-3 and AIF. This study demonstrates for the first time that sulbutiamine is able to attenuate trophic factor deprivation induced apoptotic cell death in neuronal cells in culture.