Disentangling the formation, mechanism, and evolvement of the covalent methanesulfonyl fluoride acetylcholinesterase adduct: Insights into an aged-like inactive complex susceptible to reactivation by a combination of nucleophiles

Chemical warfare nerve agents and pesticides, known as organophosphorus compounds inactivate cholinesterases (ChEs) by phosphorylating the serine hydroxyl group located at the active site of ChEs. Over the course of time, phosphorylation is followed by loss of an organophosphate-leaving group and the bond with ChEs becomes irreversible, a process known as aging. Differently, structurally related irreversible catalytic poisons bearing sulfur instead of phosphorus convert ChEs in its aged form only by covalently binding to the key catalytic serine. Kinetic and crystallographic studies of the interaction between Torpedo californica acetylcholinesterase (TcAChE) and a small organosulfonate, methanesulfonyl fluoride (MSF), indeed revealed irreversibly methylsulfonylated serine 200, to be isosteric with the bound aged sarin/soman analogues. The potent bulky reversible inhibitor 7-bis-tacrine (BTA) adopts, in the active site of the crystal structure of the MSF-enzyme adduct, a location and an orientation that closely resemble the one being found in the crystal structure of the BTA-enzyme complex. Remarkably, the presence of BTA accelerates the rate of methanesulfonylation by a factor of two. This unexpected result can be explained on the basis of two facts: i) the steric hindrance exerted by BTA to MSF in accessing the active site and ii) the acceleration of the MSF-enzyme adduct formation as a consequence of the lowering of the rotational and translational degrees of freedom in the proximity of the catalytic serine. It is well known that pralidoxime (2-Pyridine Aldoxime Methyl chloride, 2-PAM) alone or in the presence of the substrate acetylcholine cannot reactivate the active site serine of the TcAChE-MSF adduct. We show that the simultaneous presence of 2-PAM and the additional neutral oxime, 2-[(hydroxyimino)methyl]-l-methylimidazol (2-HAM), triggers the reactivation process of TcAChE within the hour timescale. Overall, our results pave the way toward the likely use of a cocktail of distinctive oximes as a promising recipe for an effective and fast reactivation of aged cholinesterases.

A-series agent A-234: initial in vitro and in vivo characterization

A-series agent A-234 belongs to a new generation of nerve agents. The poisoning of a former Russian spy Sergei Skripal and his daughter in Salisbury, England, in March 2018 led to the inclusion of A-234 and other A-series agents into the Chemical Weapons Convention. Even though five years have already passed, there is still very little information on its chemical properties, biological activities, and treatment options with established antidotes. In this article, we first assessed A-234 stability in neutral pH for subsequent experiments. Then, we determined its inhibitory potential towards human recombinant acetylcholinesterase (HssAChE; EC 3.1.1.7) and butyrylcholinesterase (HssBChE; EC 3.1.1.8), the ability of HI-6, obidoxime, pralidoxime, methoxime, and trimedoxime to reactivate inhibited cholinesterases (ChEs), its toxicity in rats and therapeutic effects of different antidotal approaches. Finally, we utilized molecular dynamics to explain our findings. The results of spontaneous A-234 hydrolysis showed a slow process with a reaction rate displaying a triphasic course during the first 72 h (the residual concentration 86.2%). A-234 was found to be a potent inhibitor of both human ChEs (HssAChE IC50 = 0.101 ± 0.003 µM and HssBChE IC50 = 0.036 ± 0.002 µM), whereas the five marketed oximes have negligible reactivation ability toward A-234-inhibited HssAChE and HssBChE. The acute toxicity of A-234 is comparable to that of VX and in the context of therapy, atropine and diazepam effectively mitigate A-234 lethality. Even though oxime administration may induce minor improvements, selected oximes (HI-6 and methoxime) do not reactivate ChEs in vivo. Molecular dynamics implies that all marketed oximes are weak nucleophiles, which may explain the failure to reactivate the A-234 phosphorus-serine oxygen bond characterized by low partial charge, in particular, HI-6 and trimedoxime oxime oxygen may not be able to effectively approach the A-234 phosphorus, while pralidoxime displayed low interaction energy. This study is the first to provide essential experimental preclinical data on the A-234 compound.

Serum Carbohydrate Antigen 19-9 and Metabolite Hypotaurine Are Predictive Markers for Early Recurrence of Pancreatic Ductal Adenocarcinoma

OBJECTIVE

A significant number of patients experience early recurrence after surgical resection for pancreatic ductal adenocarcinoma (PDAC), negating the benefit of surgery. The present study conducted clinicopathologic and metabolomic analyses to explore the factors associated with the early recurrence of PDAC.

MATERIALS AND METHODS

Patients who underwent pancreatectomy for PDAC at Kagawa University Hospital between 2011 and 2020 were enrolled. Tissue samples of PDAC and nonneoplastic pancreas were collected and frozen immediately after resection. Charged metabolites were quantified by capillary electrophoresis-mass spectrometry. Patients who relapsed within 1 year were defined as the early recurrence group.

RESULTS

Frozen tumor tissue and nonneoplastic pancreas were collected from 79 patients. The clinicopathologic analysis identified 11 predictive factors, including preoperative carbohydrate antigen 19-9 levels. The metabolomic analysis revealed that only hypotaurine was a significant risk factor for early recurrence. A multivariate analysis, including clinical and metabolic factors, showed that carbohydrate antigen 19-9 and hypotaurine were independent risk factors for early recurrence ( P = 0.045 and P = 0.049, respectively). The recurrence-free survival rate 1 year after surgery with both risk factors was only 25%.

CONCLUSIONS

Our results suggested that tumor hypotaurine is a potential metabolite associated with early recurrence. Carbohydrate antigen 19-9 and hypotaurine showed a vital utility for predicting early recurrence.

The identification of a correlation between lipid content in the model diatom Phaeodactylum tricornutum and pH treatment strategies

pH treatment promotes single-cell lipid accumulation and significantly affects microalgae growth. This study investigates the correlation between lipid content and environmental pH using the model diatom Phaeodactylum tricornutum (P. tricornutum). We compared three distinct pH treatment strategies-continuous, intermittent, and a two-phase culture-in P. tricornutum. Rigorous analysis of chlorophyll content, cell density, and lipid content indicated that ongoing pH treatment at pH 9.5 (CHES) emerged as the most effective approach for lipid accumulation in P. tricornutum. The CHES buffer treatment significantly boosted total lipid yield and led to a reduction in protein content. Carbohydrate content experienced a slight decline under CHES buffer treatment, but changes were observed in the activities of key enzymes. Specifically, [acyl-carrier-protein] S-malonyltransferase (MAT) activity decreased after 3 days in the control treatment, while no significant change was noted under the CHES buffer treatment. In contrast, diacylglycerol O-acyltransferase (DGAT) activity showed upregulation 2 and 3 days post-CHES buffer treatment. Moreover, the study identified differentially expressed genes enriched in Gene Ontology (GO) terms associated with protein biosynthesis, photosynthesis, nucleoside metabolism, and transferase activity. These outcomes underscore the pivotal role of CHES buffer in orchestrating primary metabolism, potentially steering carbon flux towards lipogenesis. As a result, the potential of microalgae as a sustainable source of biofuels contributes significantly to the transition towards a more environmentally friendly energy landscape.

Involvement of GAT2/Slc6a13 in hypotaurine uptake at fetal-facing plasma membrane of syncytiotrophoblasts at mid-to-late gestation in rats and mice

INTRODUCTION

Hypotaurine, a precursor to taurine, is known for its antioxidant properties and is prominently present in fetal plasma and the placenta. Our previous research revealed that ezrin-knockout mice experience fetal growth retardation, coinciding with reduced hypotaurine levels in fetal plasma. This study aims to elucidate the expression and role of hypotaurine transporters within the placenta.

METHODS

We employed quantitative RT-PCR to measure mRNA expression of GAT transporter family members in the placenta during mid-to-late gestation. LC/MS/MS was used to analyze the distribution of hypotaurine in different placental subregions. Immunohistochemistry was utilized to examine the localization of GAT2 in mice. Placental hypotaurine uptake from fetal circulation was studied via umbilical perfusion in rats.

RESULTS

Among hypotaurine transporters, GAT2 exhibited increased mRNA and protein expression in murine placenta during mid-to-late gestation. Notably, GAT2/Slc6a13 mRNA and hypotaurine were most concentrated in the labyrinth of murine placenta. In contrast, enzymes responsible for hypotaurine synthesis, such as cysteine dioxygenase, cysteine sulfinic acid decarboxylase, and 2-aminoethanethiol dioxygenase, showed minimal expression in the labyrinth. These findings suggest that GAT2 is a key determinant of hypotaurine levels in the placental labyrinth. Immunohistochemical examination unveiled that GAT2 was predominantly localized on the fetal-facing plasma membrane within syncytiotrophoblasts, which co-localized with ezrin. In rat umbilical perfusion experiments, the GAT2/3 and TauT inhibitor, SNAP-5114, significantly reduced hypotaurine extraction from fetal circulation to the placenta.

DISCUSSION

The results suggest that GAT2 plays a pivotal role in the concentrative uptake of hypotaurine from fetal plasma within syncytiotrophoblasts of the placenta.

Uptake of community health care provision by community health entrepreneurs for febrile illness and diarrhoea: a cross-sectional survey in rural communities in Bunyangabu district, Uganda

OBJECTIVE

To assess the uptake of services provided by community health workers who were trained as community health entrepreneurs (CHEs) for febrile illness and diarrhoea.

DESIGN

A cross-sectional survey among households combined with mapping of all providers of basic medicine and primary health services in the study area.

PARTICIPANTS

1265 randomly selected households in 15 rural villages with active CHEs.

SETTING

Bunyangabu district, Uganda.

OUTCOME MEASURES

We describe the occurrence and care sought for fever and diarrhoea in the last 3 months by age group in the households. Care provider options included: CHE, health centre or clinic (public or private), pharmacy, drug shop and other. Geographic Information Ssystem (GIS)-based geographical measures were used to map all care providers around the active CHEs.

RESULTS

Fever and diarrhoea in the last 3 months occurred most frequently in children under 5; 68% and 41.9%, respectively. For those who sought care, CHE services were used for fever among children under 5, children 5-17 and adults over 18 years of age in 34.7%, 29.9% and 25.1%, respectively. For diarrhoea among children under 5, children 5-17 and adults over 18 years of age, CHE services were used in 22.1%, 19.5% and 7.0%, respectively. For those who did not seek care from a CHE (only), drug shops were most frequently used services for both fever and diarrhoea, followed by health centres or private clinics. Many households used a combination of services, which was possible given the high density and diversity of providers found in the study area.

CONCLUSIONS

CHEs play a considerable role in providing care in rural areas where they are active. The high density of informal drug shops and private clinics highlights the need for clarity on the de facto roles played by different providers in both the public and private sector to improve primary healthcare.

Limited exposure to pancreatic ERCP during advanced endoscopy training impacts competence and performance in independent practice

BACKGROUND/OBJECTIVES

The impact of competency-based training programs on pancreatic endoscopic retrograde cholangiopancreatography (ERCP) performance remains unclear. This study aimed to describe the learning curves of pancreatic ERCP and subsequent performance during independent practice.

METHODS

This was a multicenter prospective cohort study involving advanced endoscopy trainees (AETs). In the 1st phase, trainees were assessed on every 5th ERCP using the ERCP and EUS Skills Assessment Tool (TEESAT). Cumulative sum (CUSUM) analysis of pancreatic ERCP evaluations was used to establish learning curves. During the 2nd phase (1st year of independent practice), now-graduated participants documented their performance on key ERCP quality indicators.

RESULTS

A total of 24 AETs (20 training programs) received sufficient evaluations for CUSUM analysis. Pancreatic ERCP accounted for 14.6 % (196/1339) of all ERCPs evaluated with 45 % of pancreatic ERCPs carrying a Grade 3 level of complexity. A minority of AETs (16.7 %) performed enough pancreatic ERCPs to generate meaningful learning curves with no AETs achieving competence in pancreatic cannulation, sphincterotomy, or stone clearance during Phase 1. In Phase 2, a total of 3620 ERCPs were performed, of which 281 (7.8 %) were pancreatic ERCPs. While the overall pancreatic duct cannulation rate was 92.2 %, the native papilla pancreatic duct cannulation rate was 85.7 %, which was below the recommended 90 % threshold.

CONCLUSIONS

Advanced endoscopy training offers a low level of exposure to pancreatic ERCP, which is mirrored in independent practice, highlighting the inadequate training in pancreatic ERCP. Given the complexity of pancreatic ERCP, novel strategies are warranted to improve training in pancreatic ERCP.

Cost-effectiveness of taurolidine-citrate in a cohort of patients with intestinal failure receiving home parenteral nutrition

BACKGROUND

Catheter-related bloodstream infections (CRBSIs) in patients receiving home parenteral nutrition (HPN) for chronic intestinal failure (CIF) are associated with significant morbidity and financial costs. Taurolidine is associated with a reduction in bloodstream infections, with limited information on the cost-effectiveness as the primary prevention. This study aimed to determine the cost-effectiveness of using taurolidine-citrate for the primary prevention of CRBSIs within a quaternary hospital.

METHODS

All patients with CIF receiving HPN were identified between January 2015 and November 2022. Data were retrospectively collected regarding patient demographics, HPN use, CRBSI diagnosis, and use of taurolidine-citrate. The direct costs associated with CRBSI-associated admissions and taurolidine-citrate use were obtained from the coding department using a bottom-up approach. An incremental cost-effective analysis was performed, with a time horizon of 4 years, to compare the costs associated with primary and secondary prevention against the outcome of cost per infection avoided.

RESULTS

Forty-four patients received HPN within this period. The CRBSI rates were 3.25 infections per 1000 catheter days before the use of taurolidine-citrate and 0.35 infections per 1000 catheter days after taurolidine-citrate use. The incremental cost-effectiveness ratio indicates primary prevention is the weakly dominant intervention, with the base case value of $27.04 per CRBSI avoided. This held with one-way sensitivity analysis.

CONCLUSION

Taurolidine-citrate in the primary prevention of CRBSIs in patients with CIF receiving HPN is associated with reduced hospital costs and infection rates.

In vitro and in vivo Biological Evaluation of Newly Tacrine-Selegiline Hybrids as Multi-Target Inhibitors of Cholinesterases and Monoamine Oxidases for Alzheimer's Disease

Purpose

Alzheimer's disease (AD) is the most common neurodegenerative disease, and its multifactorial nature increases the difficulty of medical research. To explore an effective treatment for AD, a series of novel tacrine-selegiline hybrids with ChEs and MAOs inhibitory activities were designed and synthesized as multifunctional drugs.

Methods

All designed compounds were evaluated in vitro for their inhibition of cholinesterases (AChE/BuChE) and monoamine oxidases (MAO-A/B) along with their blood-brain barrier permeability. Then, further biological activities of the optimizing compound 7d were determined, including molecular model analysis, in vitro cytotoxicity, acute toxicity studies in vivo, and pharmacokinetic and pharmacodynamic property studies in vivo.

Results

Most synthesized compounds demonstrated potent inhibitory activity against ChEs/MAOs. Particularly, compound 7d exhibited good and well-balanced activity against ChEs (hAChE: IC50 = 1.57 μM, hBuChE: IC50 = 0.43 μM) and MAOs (hMAO-A: IC50 = 2.30 μM, hMAO-B: IC50 = 4.75 μM). Molecular modeling analysis demonstrated that 7d could interact simultaneously with both the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE in a mixed-type manner and also exhibits binding affinity towards BuChE and MAO-B. Additionally, 7d displayed excellent permeability of the blood-brain barrier, and under the experimental conditions, it elicited low or no toxicity toward PC12 and BV-2 cells. Furthermore, 7d was not acutely toxic in mice at doses up to 2500 mg/kg and could improve the cognitive function of mice with scopolamine-induced memory impairment. Lastly, 7d possessed well pharmacokinetic characteristics.

Conclusion

In light of these results, it is clear that 7d could potentially serve as a promising multi-functional drug for the treatment of AD.

[Mechanism of acteoside in prevention and treatment of gouty arthritis based on liver metabolomics]

This study aims to reveal the effect of acteoside on gouty arthritis(GA) in rats based on liver metabolomics. The ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was employed to search for the potential biomarkers and metabolic pathways. SD rats were randomly assigned into blank, model, colchicine(0.3 mg·kg~(-1)), and high-, medium-, low-dose(200, 100, and 50 mg·kg~(-1), respectively) acteoside groups(n=7). The rats were administrated once a day for 7 continuous days. Monosodium urate(MSU) was used to induce GA model in rats during administration. The degree of joint swelling and pathological changes of synovial tissue in rats were observed, and the levels of interleukin(IL)-1β, IL-18 and tumor necrosis factor(TNF)-α in the synovial tissue of rats were measured. UPLC-Q-TOF-MS was employed to collect rat liver data, and Progenesis QI and EZ info were used for data analysis. Human Metabolomics Database(HMDB) and Kyoto Encyclopedia of Genes and Genomes(KEGG) were employed to predict the potential biomarkers and metabolic pathways. The results showed that acteoside alleviated joint swelling, reduced synovial tissue damage, and lowered the levels of inflammatory cytokines in GA rats. A total of 19 common biomarkers were identified, 17 of which can be regulated by acteoside. Seven metabolic pathways were enriched, such as glycerophospholipid metabolism, linoleic acid metabolism, and taurine and hypotaurine metabolism, among which glycerophospholipid metabolism was strongly disturbed. The metabolomics analysis suggested that acteoside may down-regulate the expression of inflammatory cytokines and alleviate the symptoms of GA rats by regulating glycerophospholipid metabolism, linoleic acid metabolism, and taurine and hypotaurine metabolism. The findings provide a reference for future research and development of acteoside.

Use of 2% taurolidine lock solution for treatment and prevention of catheter-related bloodstream infections in neonates: a feasibility study

BACKGROUND

Taurolidine lock, a technique used to prevent or treat catheter-related bloodstream infection (CRBSI), is effective in adult and paediatric patients but has been described rarely in neonates. The aim of this descriptive retrospective study, was to determine the feasibility and direct outcomes of prophylactic and therapeutic taurolidine locks in term and preterm neonates.

METHODS

We implemented the use of therapeutic taurolidine lock in addition to antibiotic treatment with the aim of catheter salvage in critical neonates with difficult vascular access (group 1). In addition, we introduced taurolidine lock as a preventive measure in neonates with a central venous catheter (CVC) at high risk of developing CRBSI (group 2). Every 24 h (in the treatment group) a 2% taurolidine solution was injected and the catheter locked for at least 120 min, until infection clearance (group 1). In the preventive group, the catheter was locked for 30 min every 48 h until CVC removal (group 2).

FINDINGS

Thirty-seven neonates who received taurolidine were included in this study. We did not observe any major adverse events. In group 1 (21 cases), clinical symptom disappearance and bacteraemia clearance were achieved without catheter removal in 18 cases (85.7%); in the other three neonates the catheter was removed shortly after the start of the locks as it was possible to replace the CVC. In group 2 (16 neonates), no CRBSI was observed during the duration of the catheter placement.

CONCLUSIONS

In this retrospective study, taurolidine was successfully used in neonates both for prevention and treatment of CRBSI, without major undesired effects. A larger cohort and a randomized clinical trial is warranted in order to establish its efficacy and safety in neonates.

A metabolomic approach to elucidate the inhibitory effects of baicalin in pulmonary fibrosis

CONTEXT

Baicalin, a major flavonoid extracted from Scutellaria baicalensis Georgi (Lamiaceae), has been shown to exert therapeutic effects on pulmonary fibrosis (PF).

OBJECTIVE

To use serum metabolomics combined with biochemical and histopathological analyses to clarify anti-PF mechanisms of baicalin on metabolic pathways and the levels of potential biomarkers.

MATERIALS AND METHODS

Forty male Sprague-Dawley rats were randomly divided into the control, PF model, prednisolone acetate-treated (4.2 mg/kg/day) and baicalin-treated (25 and 100 mg/kg/day) groups. A rat model of PF was established using a tracheal injection of bleomycin, and the respective drugs were administered intragastrically for 4 weeks. Histomorphology of lung tissue was examined after H&E and Masson's trichrome staining. Biochemical indicators including SOD, MDA and HYP were measured. Serum-metabonomic analysis based on UPLC-Q-TOF/MS was used to clarify the changes in potential biomarkers among different groups of PF rats.

RESULTS

Both doses of baicalin effectively alleviated bleomycin-induced pathological changes, and increased the levels of SOD (from 69.48 to 99.50 and 112.30, respectively), reduced the levels of MDA (from 10.91 to 5.0 and 7.53, respectively) and HYP (from 0.63 to 0.41 and 0.49, respectively). Forty-eight potential biomarkers associated with PF were identified. Meanwhile, the metabolic profiles and fluctuating metabolite levels were normalized or partially reversed after baicalin treatment. Furthermore, baicalin was found to improve PF potentially by the regulation of four key biomarkers involving taurine and hypotaurine metabolism, glutathione metabolism, and glycerophospholipid metabolism.

CONCLUSIONS

These findings revealed the anti-fibrotic mechanisms of baicalin and it may be considered as an effective therapy for PF.

The efficacy of taurolidine containing lock solutions for the prevention of central-venous-catheter-related bloodstream infections: a systematic review and meta-analysis

The incidence of central venous catheter (CVC)-related bloodstream infections is high in patients requiring a long-term CVC. Therefore, infection prevention is of the utmost importance. The aim of this study was to provide an updated overview of randomized controlled trials (RCTs) comparing the efficacy of taurolidine containing lock solutions (TL) to other lock solutions for the prevention of CVC-related bloodstream infections in all patient populations. On 15^th February 2021, PubMed, Embase and The Cochrane Library were searched for RCTs comparing the efficacy of TLs for the prevention of CVC-related bloodstream infections with other lock solutions. Exclusion criteria were non-RCTs, studies describing <10 patients and studies using TLs as treatment. Risk of bias was evaluated using the Cochrane Risk of Bias 2 tool. A random effects model was used to pool individual study incidence rate ratios (IRRs). Subgroup analyses were performed based on the following factors: CVC indication, comparator lock and bacterial isolates cultured. A total of 14 articles were included in the qualitative synthesis describing 1219 haemodialysis, total parenteral nutrition and oncology patients. The pooled IRR estimated for all patient groups together (nine studies; 918 patients) was 0.30 (95% confidence interval 0.19-0.46), favouring the TLs. Adverse events (10 studies; 867 patients) were mild and scarce. The quality of the evidence was limited due to a high risk of bias and indirectness of evidence. The use of TLs might be promising for the prevention of CVC-related bloodstream infections. Large-scale RCTs are needed to draw firm conclusions on the efficacy of TLs.

Levels of taurine, hypotaurine and homotaurine, and amino acids profiles in selected commercial seaweeds, microalgae, and algae-enriched food products

Amino acids and sulfonic acid derivatives (Taurine-Tau; Hypotaurine-HypTau; Homotaurine-HTau) of 26 different species of commercial macroalgae, microalgae and 10 algae-enriched food products from the market were quantified in a single chromatographic run. Tau and analogues were predominantly distributed in red species followed by green and brown species. Palmaria palmata, Gracilaria longissima and Porphyra sp. were the species with the highest content of Tau and total sulfonic acid derivatives (TAD). Notwithstanding, relatively high concentrations of HTau were found in green algae Ulva lactuca and G. vermicullophyla as well as in the brown algae Undaria pinnatifida. HTau and HypTau were found at lower concentrations than Tau in all species, except in Ulva lactuca. The samples with the highest protein content were the green species Chlorella vulgaris, Nannochloropsis, and Afanizomenon-flos aquae, followed by the red algae Gracilaria longissima and Gracilaria vermicullophyla. Samples of pasta formulated with algae ingredients contained the highest levels of sulfonic acid derivatives, evidencing that these products can provide levels of TAD comparable to those found in foods of animal origin. This study provides, for the first time, quantitative information regarding the distribution of sulfonic acid derivatives and total amino acids in multiple algae species as well as the nutritional impact of the inclusion of algae ingredients in commercial food matrices.

A 2% taurolidine catheter lock solution prevents catheter-related bloodstream infection (CRBSI) and catheter dysfunction in hemodialysis patients

HIGHLIGHTS

2% taurolidine catheter lock solution without additives is safe and efficient. CRBSI and dysfunction rates compare favorably against other studies in hemodialysis.

BACKGROUND

In hemodialysis patients, catheter-related bloodstream infection (CRBSI) and catheter dysfunction are common and cause significant morbidity, mortality, and costs. Catheter lock solutions reduce CRBSI and catheter dysfunction rates, but solutions containing heparin, citrate, or antibiotics are associated with adverse effects. Due to its antimicrobial and antithrombotic properties and benign safety profile, taurolidine is suitable for use in catheter lock solutions. In this study the effectiveness and safety of a catheter lock solution containing 2% taurolidine without citrate or heparin (TauroSept®, Geistlich Pharma AG, Wolhusen, Switzerland) in hemodialysis patients were investigated for the first time.

METHODS

Data from 21 patients receiving chronic hemodialysis via tunneled central venous catheters with 2% taurolidine solution as a catheter lock were analyzed in a single-center retrospective study and compared with the existing literature in a review. The primary endpoint was CRBSI rate. Secondary endpoints included catheter dysfunction, treatment, and costs; catheter technical problems, resolution, and costs; and adverse events. Data were compared to outcomes with standard lock solutions in the literature.

RESULTS

No CRBSIs occurred during the observation period of 5,639 catheter days. The catheter dysfunction rate was 0.71 per 1,000 catheter days, and the catheter dysfunction treatment costs were CHF (Swiss Franc) 543 per patient. No technical problems or adverse events related to the use of 2% taurolidine-containing catheter lock solution were observed. These results compare favorably with other catheter lock solutions.

CONCLUSIONS

A solution containing 2% taurolidine seems suitable as a hemodialysis catheter lock. In a Swiss cohort, it prevented CRBSI, limited catheter dysfunction, and was cost-efficient.

Homotaurine limits the spreading of T cell autoreactivity within the CNS and ameliorates disease in a model of multiple sclerosis

Most multiple sclerosis (MS) patients given currently available disease-modifying drugs (DMDs) experience progressive disability. Accordingly, there is a need for new treatments that can limit the generation of new waves T cell autoreactivity that drive disease progression. Notably, immune cells express GABAA-receptors (GABAA-Rs) whose activation has anti-inflammatory effects such that GABA administration can ameliorate disease in models of type 1 diabetes, rheumatoid arthritis, and COVID-19. Here, we show that oral GABA, which cannot cross the blood-brain barrier (BBB), does not affect the course of murine experimental autoimmune encephalomyelitis (EAE). In contrast, oral administration of the BBB-permeable GABAA-R-specific agonist homotaurine ameliorates monophasic EAE, as well as advanced-stage relapsing-remitting EAE (RR-EAE). Homotaurine treatment beginning after the first peak of paralysis reduced the spreading of Th17 and Th1 responses from the priming immunogen to a new myelin T cell epitope within the CNS. Antigen-presenting cells (APC) isolated from homotaurine-treated mice displayed an attenuated ability to promote autoantigen-specific T cell proliferation. The ability of homotaurine treatment to limit epitope spreading within the CNS, along with its safety record, makes it an excellent candidate to help treat MS and other inflammatory disorders of the CNS.

Possible Roles of Hypotaurine and Thiotaurine in the Vesicomyid Clam Phreagena okutanii

AbstractVesicomyid clams, which inhabit deep-sea hydrothermal vents and hydrocarbon seeps, are nutritionally dependent on symbiotic, chemoautotrophic bacteria that produce organic matter by using hydrogen sulfide. Vesicomyid clams absorb hydrogen sulfide from the foot and transport it in their hemolymph to symbionts in the gill. However, mechanisms to cope with hydrogen sulfide toxicity are not fully understood. Previous studies on vent-specific invertebrates, including bathymodiolin mussels, suggest that hypotaurine, a precursor of taurine, mitigates hydrogen sulfide toxicity by binding it to bisulfide ion, so as to synthesize thiotaurine. In this study, we cloned cDNAs from the vesicomyid clam Phreagena okutanii for the taurine transporter that transports hypotaurine into cells and for cysteine dioxygenase and cysteine-sulfinate decarboxylase, major enzymes involved in hypotaurine synthesis. Results of reverse-transcription polymerase chain reaction indicate that mRNAs of these three genes are most abundant in the foot, followed by the gill. However, hypotaurine and thiotaurine levels, measured by reverse-phase high-performance liquid chromatography, were low in the foot and high in the gill. In addition, thiotaurine was detected in hemolymph cells. Hypotaurine synthesized in the foot may be transported to the gill after binding to bisulfide ion, possibly by hemolymph cells.

Effectiveness of Perindopril/Indapamide Single-Pill Combination in Uncontrolled Patients with Hypertension: A Pooled Analysis of the FORTISSIMO, FORSAGE, ACES and PICASSO Observational Studies

INTRODUCTION

Our objective was to determine the effectiveness of a perindopril/indapamide (Per/Ind) single-pill combination (SPC) in a broad range of patient profiles, including subgroups with varying hypertension severity, age and cardiovascular risk profiles.

METHODS

Patient data from four large prospective observational studies (FORTISSIMO, FORSAGE, PICASSO, ACES) were pooled. In each study, patients already treated for hypertension were switched to Per/Ind 10/2.5 mg SPC and systolic and diastolic blood pressure (SBP/DBP) measured at the 1-month (M1) and 3-month (M3) visits. Study endpoints included change in SBP and DBP from baseline to M1 and M3 and the percentage of patients achieving BP control (SBP/DBP < 140/90 mmHg for patients without diabetes or < 140/85 mmHg for patients with diabetes).

RESULTS

A total of 16,763 patients were enrolled and received Per/Ind (94% received the full dose of 10/2.5). Mean patient age was 61.4 years (36% were ≥ 65 years old), 57% were women, and 16% had isolated systolic hypertension (ISH). Mean baseline office SBP/DBP was 162/94 mmHg, and mean duration of hypertension was 11 years. Cardiovascular risk factors and comorbid conditions were common in this population. Significant mean reductions in SBP (- 23 mmHg) and DBP (- 11 mmHg) were observed at M1 compared with baseline (P < 0.001), which were maintained at M3 (- 30 mmHg and - 14 mmHg, respectively). At M3, BP control was achieved by 70% of patients (78% for ISH). In patients with SBP ≥ 180 mmHg at baseline (grade III hypertension), the mean SBP/DBP decrease was - 51/- 20 mmHg and 53% achieved BP control. Per/Ind was well tolerated with an overall rate of adverse events of 1.3%, most frequently cough and dizziness at rates of 0.3% and 0.2%, respectively.

CONCLUSION

In this hypertensive population including difficult-to-control patient subgroups, switching to Per/Ind 10/2.5 mg SPC led to rapid and important reductions in BP. BP control was achieved in 70% of patients overall in an everyday practice context.

Resveratrol administration prevents radiation-related changes in metabolic profiles of hearts 20 weeks after irradiation of mice with a single 2 Gy dose

We aimed to evaluate whether resveratrol affects radiation-induced changes in metabolite profiles of the mouse heart. Hearts were irradiated in vivo with a single 2 Gy dose during the resveratrol administration and metabolite profiles of heart tissue were analyzed by the untargeted HR-MAS NMR approach twenty weeks after irradiation. The administration of resveratrol mitigated the radiation-induced decline in the content of choline-containing compounds and unsaturated lipids, which might reflect the stabilization of cell membrane structure against radiation-related damage. Results obtained with this mouse model suggest that the resveratrol supplementation may prevent metabolic changes related to radiation-induced damage in the heart.

Effects of Citicoline, Homotaurine, and Vitamin E on Contrast Sensitivity and Visual-Related Quality of Life in Patients with Primary Open-Angle Glaucoma: A Preliminary Study

The aim of the present study was to evaluate the effects of supplementation with a fixed combination of citicoline 500 mg, homotaurine 50 mg, and vitamin E 12 mg (CIT/HOMO/VITE) on contrast sensitivity and visual-related quality of life in patients with primary open-angle glaucoma (POAG) in mild stage. This was a multicenter, observational, cross-over, short-term, pilot study on POAG patients with stable controlled intraocular pressure (IOP). Patients were randomly assigned to Group 1 (current topical therapy for 4 months and then current topical therapy plus CIT/HOMO/VITE for 4 months) or Group 2 (CIT/HOMO/VITE in addition to current topical therapy for 4 months and then topical therapy alone for 4 months). Best-corrected visual acuity, IOP, visual field, and the Spaeth/Richman contrast sensitivity (SPARCS) test score were recorded at baseline and after 4 and 8 months. The Glaucoma Quality of Life-15 (GQL-15) questionnaire was administered at each check time. Forty-four patients were assigned to Group 1 and 65 to Group 2. Over the follow-up period, there were no significant changes in IOP or visual field findings, whereas SPARCS and GQL-15 findings significantly varied from baseline, both being improved in subjects treated with CIT/HOMO/VITE fixed combination. These results demonstrate that a daily intake of a fixed combination of citicoline, homotaurine, and vitamin E in addition to the topical medical treatment significantly increased the total score of the contrast sensitivity test and the quality of life in patients with POAG.

Role of taurine, its haloamines and its lncRNA TUG1 in both inflammation and cancer progression. On the road to therapeutics? (Review)

For one century, taurine is considered as an end product of sulfur metabolism. In this review, we discuss the beneficial effect of taurine, its haloamines and taurine upregulated gene 1 (TUG1) long non‑coding RNA (lncRNA) in both cancer and inflammation. We outline how taurine or its haloamines (N‑Bromotaurine or N‑Chlorotaurine) can induce robust and efficient responses against inflammatory diseases, providing insight into their molecular mechanisms. We also provide information about the use of taurine as a therapeutic approach to cancer. Taurine can be combined with other chemotherapeutic drugs, not only mediating durable responses in various malignancies, but also circumventing the limitations met from chemotherapeutic drugs, thus improving the therapeutic outcome. Interestingly, the lncRNA TUG1 is regarded as a promising therapeutic approach, which can overcome acquired resistance of cancer cells to selected strategies. In this regard, we can translate basic knowledge about taurine and its TUG1 lncRNA into potential therapeutic options directed against specific oncogenic signaling targets, thereby bridging the gap between bench and bedside.

Impact of the column on effluent pH in cation exchange pH gradient chromatography, a practical study

In ionexchange chromatography, the pH gradient mode becomes more and more popular today for the analysis of therapeutic proteins as this mode can provide higher or alternative selectivity to the commonly used salt gradient mode. Ideally, a linear pH response is expected when performing linear gradients. However up to now, only a very few buffer systems have been developed and are commercially available which can perform nearly linear pH responses when flowing through a given column. It is also known that a selected buffer system (mobile phase) can work well on one column but can fail on other column. The goal of this study was to practically evaluate the effects that ionexchange columns (weak and strong exchangers) might have on effluent pH, when performing linear pH gradient separations of therapeutic monoclonal antibodies. To attain this objective, the pH was monitored on-line at the column outlet using a specific setup. To make comprehensive observations of the phenomenon, four different mobile phase conditions and five cation exchange columns (weak and strong exchangers) were employed. The obtained pH responses were systematically compared to responses measured in the absence of the columns. From this work, it has become clear that both the column and mobile phase can have significant effects on pH gradient chromatography and that their combination must be considered when developing a new method. Phase systems (column + mobile phase) providing linear pH responses are indeed the most suitable for separating mAbs with different isoelectric points and, with them, it is possible to elute mAbs across wide retention time ranges and with high selectivity.

Taurolidine lock solution for catheter-related bloodstream infections in pediatric patients: A meta-analysis

Infection is one of the most commonly described complications, and a major cause of morbidity and mortality in pediatric patients treated using central venous catheters (CVCs). Taurolidine lock solutions have been used to decrease catheter-related bloodstream infections (CRBSIs) in both adult and pediatric patients. The purpose of this study was to systematically search the literature and conduct a meta-analysis to determine the efficacy of taurolidine in reducing CRBSI in children. We conducted an electronic search of the PubMed, EMBASE, Cochrane Library, TRIP Database, CINAHL, and Google Scholar databases for articles published up to 1^st November 2019. Eligible studies included randomized controlled trials (RCTs) comparing the effects of taurolidine with control for preventing CRBSI in pediatric patients. Four studies were included. Our results indicated a statistical significant reduction in the total number of CRBSI with taurolidine as compared to control (RR: 0.23; 95% CI:0.13, 0.40; I² = 0%; P<0.00001). The pooled analysis also indicated a statistical significant reduction in the incidence of CRBSI (defined as the number of CRBSI events/1000 catheter days) in the taurolidine group (MD: -1.12; 95% CI:-1.54, -0.71; I² = 1%; P<0.00001). The number of catheters removed due to infection or suspected infection was not significantly different between the two groups (RR: 0.68; 95% CI:0.22, 2.10; I² = 56%; P = 0.50) (Fig 5). The quality of the included studies was not high. The use of taurolidine as a catheter locking solution may significantly reduce CRBSI in pediatric patients. However, the quality of current evidence is not high and further high-quality large scale RCTs are needed to corroborate our results.

In-vitro effects of taurolidine alone and in combination with mitoxantrone and/or piroxicam on canine transitional cell carcinoma

The objective of this in-vitro study was to evaluate taurolidine as a therapy for transitional cell carcinomas in canine patients. Transitional cell carcinoma (TCC) is the most common cancer of the urinary bladder in dogs and accounts for approximately 2% of reported malignancies in this species. There is no cure for this neoplasm and most dogs are lost from complications associated with progression of the local disease. Taurolidine has been shown to have anti-tumor and antiangiogenic effects against a variety of neoplasms in human and animal models. Four canine TCC cell lines were treated with various concentrations of taurolidine, mitoxantrone, and piroxicam alone. In addition, combinations of taurolidine/mitoxantrone, taurolidine/piroxicam, mitoxantrone/piroxicam, and taurolidine/mitoxantrone/piroxicam were assessed. Susceptibility of the TCC cell lines was based on a 72-hour growth inhibition assay using resazurin with absorbance measured at λ530/590. The ability of taurolidine to induce apoptosis was evaluated on 2 of the cell lines with an Annexin-V/propidium iodide assay. All cell lines were susceptible to treatment with taurolidine, mitoxantrone, and piroxicam alone. The results of the combination therapies of the 3 drugs were dependent on cell line and concentration and revealed no change in cell growth inhibition, a subadditive relationship, or a synergistic relationship. Taurolidine induced apoptosis in a concentration- and time-dependent fashion. Taurolidine alone showed significant effects on cell viability in vitro in canine TCC cell lines and these effects can be potentially enhanced with the addition of mitoxantrone and/or piroxicam.

Antimicrobial Locks in Patients Receiving Home Parenteral Nutrition

Catheter-related bloodstream infection (CRBSI) is one of the most common and potentially fatal complications in patients receiving home parenteral nutrition (HPN). In order to prevent permanent venous access loss, catheter locking with an antimicrobial solution has received significant interest and is often a favored approach as part of the treatment of CRBSI, but mainly for its prevention. Several agents have been used for treating and preventing CRBSI, for instance antibiotics, antiseptics (ethanol, taurolidine) and, historically, anticoagulants such as heparin. Nonetheless, current guidelines do not provide clear guidance on the use of catheter locks. Therefore, this review aims to provide a better understanding of the current use of antimicrobial locking in patients on HPN as well as reviewing the available data on novel compounds. Despite the fact that our current knowledge on catheter locking is still hampered by several gaps, taurolidine and ethanol solutions seem promising for prevention and potentially, but not proven, treatment of CRBSI. Additional studies are warranted to further characterize the efficacy and safety of these agents.

Protective Efficacy of a Dietary Supplement Based on Forskolin, Homotaurine, Spearmint Extract, and Group B Vitamins in a Mouse Model of Optic Nerve Injury

Glaucoma is a multifactorial blinding disease with a major inflammatory component ultimately leading to apoptotic retinal ganglion cell (RGC) death. Pharmacological treatments lowering intraocular pressure can help slow or prevent vision loss although the damage caused by glaucoma cannot be reversed. Recently, nutritional approaches have been evaluated for their efficacy in preventing degenerative events in the retina although mechanisms underlying their effectiveness remain to be elucidated. Here, we evaluated the efficacy of a diet supplement consisting of forskolin, homotaurine, spearmint extract, and vitamins of the B group in counteracting retinal dysfunction in a mouse model of optic nerve crush (ONC) used as an in vivo model of glaucoma. After demonstrating that ONC did not affect retinal vasculature by fluorescein angiography, we determined the effect of the diet supplement on the photopic negative response (PhNR) whose amplitude is strictly related to RGC integrity and is therefore drastically reduced in concomitance with RGC death. We found that the diet supplementation prevents the reduction of PhNR amplitude (p < 0.001) and concomitantly counteracts RGC death, as in supplemented mice, RGC number assessed immunohistochemically is significantly higher than that in non-supplemented animals (p < 0.01). Major determinants of the protective efficacy of the compound are due to a reduction of ONC-associated cytokine secretion leading to decreased levels of apoptotic markers that in supplemented mice are significantly lower than in non-supplemented animals (p < 0.001), ultimately causing RGC survival and ameliorated visual dysfunction. Overall, our data suggest that the above association of compounds plays a neuroprotective role in this mouse model of glaucoma thus offering a new perspective in inflammation-associated neurodegenerative diseases of the inner retina.

N-acyl taurines are endogenous lipid messengers that improve glucose homeostasis

Fatty acid amide hydrolase (FAAH) degrades 2 major classes of bioactive fatty acid amides, the N-acylethanolamines (NAEs) and N-acyl taurines (NATs), in central and peripheral tissues. A functional polymorphism in the human FAAH gene is linked to obesity and mice lacking FAAH show altered metabolic states, but whether these phenotypes are caused by elevations in NAEs or NATs is unknown. To overcome the problem of concurrent elevation of NAEs and NATs caused by genetic or pharmacological disruption of FAAH in vivo, we developed an engineered mouse model harboring a single-amino acid substitution in FAAH (S268D) that selectively disrupts NAT, but not NAE, hydrolytic activity. The FAAH-S268D mice accordingly show substantial elevations in NATs without alterations in NAE content, a unique metabolic profile that correlates with heightened insulin sensitivity and GLP-1 secretion. We also show that N-oleoyl taurine (C18:1 NAT), the most abundant NAT in human plasma, decreases food intake, improves glucose tolerance, and stimulates GPR119-dependent GLP-1 and glucagon secretion in mice. Together, these data suggest that NATs act as a class of lipid messengers that improve postprandial glucose regulation and may have potential as investigational metabolites to modify metabolic disease.

Six new polyhydroxylated steroids conjugated with taurine, microdiscusols A-F, from the Arctic starfish Asterias microdiscus

Six new polyhydroxylated steroids conjugated with taurine, microdiscusols A-F, were isolated from the alcoholic extract of the Arctic starfish Asterias microdiscus. Three of them have been found to have additional sulfate groups in tetracyclic cores. The structures of new compounds were established by 1D and 2D NMR and HRESIMS techniques. The found steroid taurine conjugates resemble, by their structures, salts of bile acids and alcohols of lower vertebrates.

Comparing the cytotoxicity of taurolidine, mitomycin C, and oxaliplatin on the proliferation of in vitro colon carcinoma cells following pressurized intra-peritoneal aerosol chemotherapy (PIPAC)

BACKGROUND

Besides its known antibacterial effect commonly used in intraperitoneal lavage, taurolidine has been observed to possess antineoplastic properties. In order to analyse this antineoplastic potential in a palliative therapeutic setting, taurolidine (TN) was compared to mitomycin C (MMC) and oxaliplatin (OX), known antineoplastic agents which are routinely used in intraperitoneal applications, following pressurized intra-peritoneal aerosol chemotherapy (PIPAC).

METHODS

An in vitro model was established using a colon adenocarcinoma cell line (HT-29 human cells). Different experimental dosages of TN and combinations of TN, MMC, and OX were applied via PIPAC. To measure cell proliferation, a colorimetric tetrazolium reduction assay was utilized 24 h after PIPAC.

RESULTS

We demonstrated a cytotoxic effect of TN and OX (184 mg/150 mL, p < 0.01) on tumor cell growth. An increasing dosage of TN (from 0.5 g/100 mL to 0.75 g/150 mL) correlated with higher cell toxicity when compared to untreated cells (p < 0.05 and p < 0.01, respectively). PIPAC with OX and both OX and TN (0.5 g/100 mL) showed the same cytotoxic effect (p < 0.01). No significant impact was observed for MMC (14 mg/50 mL, p > 0.05) or MMC with OX (p > 0.05) applied via PIPAC.

CONCLUSIONS

The intraperitoneal application of TN is mostly limited to lavage procedures in cases of peritonitis. Our results indicate a substantial antineoplastic in vitro effect on colon carcinoma cells following PIPAC application. While this effect could be used in the palliative treatment of peritoneal metastases, further clinical studies are required to investigate the feasibility of TN application in such cases.

Taurine and its analogs in neurological disorders: Focus on therapeutic potential and molecular mechanisms

Taurine is a sulfur-containing amino acid and known as semi-essential in mammals and is produced chiefly by the liver and kidney. It presents in different organs, including retina, brain, heart and placenta and demonstrates extensive physiological activities within the body. In the several disease models, it attenuates inflammation- and oxidative stress-mediated injuries. Taurine also modulates ER stress, Ca2+ homeostasis and neuronal activity at the molecular level as part of its broader roles. Different cellular processes such as energy metabolism, gene expression, osmosis and quality control of protein are regulated by taurine. In addition, taurine displays potential ameliorating effects against different neurological disorders such as neurodegenerative diseases, stroke, epilepsy and diabetic neuropathy and protects against injuries and toxicities of the nervous system. Several findings demonstrate its therapeutic role against neurodevelopmental disorders, including Angelman syndrome, Fragile X syndrome, sleep-wake disorders, neural tube defects and attention-deficit hyperactivity disorder. Considering current biopharmaceutical limitations, developing novel delivery approaches and new derivatives and precursors of taurine may be an attractive option for treating neurological disorders. Herein, we present an overview on the therapeutic potential of taurine against neurological disorders and highlight clinical studies and its molecular mechanistic roles. This article also addresses the neuropharmacological potential of taurine analogs.

Inactivation of Adenovirus in Water by Natural and Synthetic Compounds

Millions of people use contaminated water sources for direct consumption. Chlorine is the most widely disinfection product but can produce toxic by-products. In this context, natural and synthetic compounds can be an alternative to water disinfection. Therefore, the aim of this study was to assess the inactivation of human adenovirus by N-chlorotaurine (NCT), bromamine-T (BAT) and Grape seed extract (GSE) in water. Distilled water artificially contaminated with recombinant human adenovirus type 5 (rAdV-GFP) was treated with different concentrations of each compound for up to 120 min, and viral infectivity was assessed by fluorescence microscopy. The decrease in activity of the compounds in the presence of organic matter was evaluated in water supplemented with peptone. As results, NCT and GSE inactivated approximately 2.5 log₁₀ of adenovirus after 120 min. With BAT, more than 4.0 log₁₀ decrease was observed within 10 min. The oxidative activity of 1% BAT decreased by 50% in 0.5% peptone within a few minutes, while the reduction was only 30% for 1% NCT in 5% peptone after 60 min. Organic matter had no effect on the activity of GSE. Moreover, the minimal concentration of BAT and GSE to kill viruses was lower than that known to kill human cells. It was concluded that the three compounds have potential to be used for water disinfection for drinking or reuse purposes.

Fructus Gardeniae-induced gastrointestinal injury was associated with the inflammatory response mediated by the disturbance of vitamin B6, phenylalanine, arachidonic acid, taurine and hypotaurine metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Fructus Gardenia (FG) is a widely used bitter and cold herb for clearing heat and detoxicating. Currently, toxicity of FG and its relative formula has been reported in many clinical and animal studies. However, no systematic research has been carried out on FG-related gastrointestinal (GI) injury which has been emphasized in China since the Ming Dynasty.

AIM OF THE STUDY

The purpose of this article is to investigate whether FG could damage GI and explore the mechanisms involved.

MATERIAL AND METHODS

FG was given to male mice by 7-day intragastric administration at average doses of 0.90 g (L group), 1.50 g (M group), and 3.00 g (H group) crude drug/kg FG. Comprehensive understanding of changes in weight, diarrhea degree, stool routine, histomorphology and inflammatory factors of stomach, small intestine, and colon for evaluating the effect of different doses of FG on GI injury. Moreover, metabolomics-based mechanisms exploration of FG on GI injury was carried out via HPLC-Q-TOF/MS analysis on mice urine.

RESULTS

High dose FG caused GI injury with serious diarrhea, decreased weight, abnormal stool routine, sever alteration in histomorphology of small intestine and colon (mild change in stomach), and significant change in inflammatory factors. The results of metabolomics suggested that 55 endogenous metabolites dispersed in 21 significantly altered metabolic pathways in 3.00 g/kg crude FG treated mice. The hub metabolites of GI injury were mainly related with vitamin B6 metabolism, phenylalanine metabolism, arachidonic acid metabolism, and taurine and hypotaurine metabolism via correlated network analysis.

CONCLUSION

FG affected the normal functions of GI via the regulating a variety of metabolic pathways to an abnormal state, and our results provided a research paradigm for the GI-injury of the relative bitter and cold traditional Chinese medicines.

Increased circulating conjugated primary bile acids are associated with hyperandrogenism in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common metabolic disorder with hyperandrogenism as the core pathophysiologic feature. Increased bile acids and altered bile acid pool composition have been implicated in the pathogenesis of several metabolic diseases. Thus, this study aimed to clarify the specific alterations in circulating bile acids in patients with PCOS and investigate its associations with hyperandrogenism. We recruited 37 patients with PCOS and 35 age- and BMI-matched control subjects. Serum bile acids and androgen profiles were assessed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Compared with control subjects, glycine- and taurine-conjugated primary bile acids were significantly elevated in patients with PCOS (P = 0.001 and P < 0.001). In addition, these conjugated primary bile acids were significantly and positively associated with serum concentrations of total testosterone and androstenedione in the PCOS group. In conclusion, increased circulating conjugated primary bile acids are positively associated with hyperandrogenism in women with PCOS. Further studies are warranted to explore the underlying mechanism.

Contributions of Mass Spectrometry to the Identification of Low Molecular Weight Molecules Able to Reduce the Toxicity of Amyloid-β Peptide to Cell Cultures and Transgenic Mouse Models of Alzheimer's Disease

Alzheimer's Disease affects approximately 33 million people worldwide and is characterized by progressive loss of memory at the cognitive level. The formation of toxic amyloid oligomers, extracellular amyloid plaques and amyloid angiopathy in brain by amyloid beta peptides are considered a part of the identified mechanism involved in disease pathogenesis. The optimal treatment approach leads toward finding a chemical compound able to form a noncovalent complex with the amyloid peptide thus blocking the process of amyloid aggregation. This direction gained an increasing interest lately, many studies demonstrating that mass spectrometry is a valuable method useful for the identification and characterization of such molecules able to interact with amyloid peptides. In the present review we aim to identify in the scientific literature low molecular weight chemical compounds for which there is mass spectrometric evidence of noncovalent complex formation with amyloid peptides and also there are toxicity reduction results which verify the effects of these compounds on amyloid beta toxicity towards cell cultures and transgenic mouse models developing Alzheimer's Disease.

In vitro comparison of efficacy of catheter locks in the treatment of catheter related blood stream infection

BACKGROUND & AIMS

Venous access used for parenteral nutrition (PN) application is extremely important for patients with intestinal failure. Potential loss of venous access might be a catastrophy for the patient. Catheter infections are a serious complication of PN application. Systemic administration of antibiotics as well as local antibiotic locks into the catheter to sterilize the catheter are used to treat catheter infections. However, there is no clear recommendation applying use of antibiotic locks, that would specify the type and concentration of antimicrobial medication. Our objective were to compare the efficacy of different types of antimicrobial lock therapy (especially taurolidine) and their concentrations to eradicate infectious agents.

METHODS

Bacterial strains of microorganisms (Staphylococcus epidermidis, Staphylococcus aureus, methicillin resistant S. aureus (MRSA), Pseudomonas aeruginosa, multidrug-resistant P. aeruginosa, Candida albicans) were used. Subsequently, the catheter was exposed to the microbes and then was incubated with a specific lock for 2 or 24 h at 37 °C. We used these locks: ethanol 70%, taurolidine, gentamicine in concentrations 0,5, 1 and 10 mg/ml and vancomycine in concentrations 1, 5, and 10 mg/ml. The number of remaining CFU (colony forming units) was compared after incubation.

RESULTS

70% ethanol and taurolidine were most effective for all studied microorganisms. Gentamicine was more effective than vancomycine.

CONCLUSIONS

The most effective antimicrobial lock solutions to eradicate selected pathogenic agents were ethanol and taurolidine. Use of antibiotics is often effective after many hours of treatment and there is a risk of inadequate therapy.

Future strategies of management of Alzheimer's Disease. The role of homotaurine

Dementia and Alzheimer's Disease (AD) particularly will become in future one of the major problems that healthcare systems will have to face with in developed but also in developing countries, because of the progressive aging of the population and the age-associated increase in their incidence. There is a rapid increasing in life expectancy and in elderly percentage. Unfortunately, improvements in lifespan have not been matched by improvements in mental health span. In recent years, there has been a growing interest, supported by a large number of experimental, epidemiological and clinical studies, about the beneficial effects of some natural products in preventing various age-related pathologic conditions, including brain aging and neurodegeneration. Homotaurine, a small aminosulfonate substance that is present in different species of marine red algae, has been shown, in both in vitro and in vivo studies, to provide a relevant neuroprotective effect by its specific anti-amyloid activity and by its γ-aminobutyric acid type A receptor affinity. The name homotaurine was chosen because of its large homology with taurine (2 aminoethanesulfonate), which is one of the most abundant free amino acids in the brain. The two molecules share a very similar structure, but homotaurine contains one additional carbon. The therapeutic efficacy of homotaurine in AD has been investigated in three phase II, and in three Phase III clinical studies that did not reach their pre-defined primary endpoints. However, post-hoc analyses have shown positive and significant effects on secondary endpoints and subgroups of patients, including a reduction in hippocampal volume loss and lower decline in memory function in the overall cohort, as well as a reduction in global cognitive decline in APOE ε4 allele carriers, suggesting disease-modifying effects. Also in three post marketing (as supplement) studies in patients with Mild Cognitive Impairment (MCI) the results are very promising. In this review, we will present the pre-clinical and clinical evidence supporting the potential role of homotaurine as a promising candidate for both primary and secondary prevention of AD.

Nuclear magnetic resonance-based metabolomic investigation reveals metabolic perturbations in PM2.5-treated A549 cells

Exposure to PM_2.5 is associated with an increased risk of lung diseases, and oxidative damage is the main reason for PM_2.5-mediated lung injuries. However, little is known about the early molecular events in PM_2.5-induced lung toxicity. In the present study, the metabolites in PM_2.5-treated A549 cells were examined via a robust and nondestructive nuclear magnetic resonance (NMR)-based metabolic approach to clarify the molecular mechanism of PM_2.5-induced toxicity. NMR analysis revealed that 12 metabolites were significantly altered in PM_2.5-treated A549 cells, including up-regulation of alanine, valine, lactate, ω-6 fatty acids, and citrate and decreased levels of gamma-aminobutyric acid, acetate, leucine, isoleucine, D-glucose, lysine, and dimethylglycine. Pathway analysis demonstrated that seven metabolic pathways which included alanine, aspartate and glutamate metabolism, aminoacyl-tRNA biosynthesis, taurine and hypotaurine metabolism, arginine and proline metabolism, starch and sucrose metabolism, valine, leucine and isoleucine biosynthesis, and tricarboxylic acid cycle were mostly influenced. Our results indicate that NMR technique turns out to be a simple and reliable method for exploring the toxicity mechanism of air pollutant.

Taurine Chloramine Prevents Neuronal HT22 Cell Damage Through Nrf2-Related Heme Oxygenase-1

Oxidative cell damages are able to contribute to neuronal degeneration in several diseases of the central nervous system (CNS) including stroke as well as ischemia. Heme oxygenase (HO)-1 plays a major role in the pathogenesis of neuronal disorder. Taurine chloramine (TauCl) has been shown to possess strong neuronal activities; however, the direct effects of TauCl on neuronal cell death remain to be determined. Therefore, this study was designed to assess the neuroprotective effect of TauCl using oxidative stress-stimulated mouse hippocampal HT22 cells. TauCl showed protective effects against oxidative stress-induced neurotoxicity and inhibited the reactive oxygen species (ROS) production by inducing the heme oxygenase (HO)-1 expression in HT22 cells. TauCl upregulated HO-1 expression and it also increased the nuclear factor E2-related factor 2 (Nrf2) translocation to nuclear. Using an inhibitor of HO-1 activity, we verified that the oxidative stress-related HT22 cell death was significantly suppressed by TauCl. In addition, we found reduced TauCl-induced HO-1 expression and cytoprotection following treatment of the cells with an extracellular signal-regulated kinase (ERK) inhibitor (PD98059) or a p38 inhibitor (SB203580), but not following treatment with a SP600125 as a c-Jun NH2-terminal kinase (JNK) inhibitor. These findings suggest that TauCl improves cellular damage induced by glutamate or H2O2 through ERK and p38, Nrf2, and HO-1 pathways in HT22 cells.

Taurine Chloramine Suppresses LPS-Induced Neuroinflammatory Responses through Nrf2-Mediated Heme Oxygenase-1 Expression in Mouse BV2 Microglial Cells

The brain is sensitive to the inflammation and oxidative stress that can cause the aging or neurodegenerative diseases. We investigated the anti-neuroinflammatory activities of taurine chloramine (TauCl) on lipopolysaccharide (LPS)-treated mouse BV2 microglia mediated through heme oxygenase (HO)-1 expression. TauCl inhibited the protein expressions of prostaglandin E2 (PGE2), cyclooxygenase (COX)-2, nitric oxide (NO), and inducible nitric oxide synthase (iNOS) in LPS-treated BV2 microglia. TauCl markedly inhibited interleukin-6 (IL-6), interleukin-1𝛽 (IL-1𝛽) and tumor necrosis factor-𝛼 (TNF-𝛼) production. These effects were related to the suppression of the degradation and phosphorylation of inhibition of nuclear factor kappa B-𝛼 (I𝜅B-𝛼), translocation of nuclear factor kappa B (NF-𝜅B) as well as DNA binding activity. In addition, TauCl induced the HO-1 expression by increasing the nuclear factor E2-related factor 2 (Nrf2) translocation to the nucleus in mouse BV2 microglia. These findings suggest that TauCl has protective effects of neurodegenerative disorders caused by neuroinflammation.

Carbonate Anion Radical Generated by the Peroxidase Activity of Copper-Zinc Superoxide Dismutase: Scavenging of Radical and Protection of Enzyme by Hypotaurine and Cysteine Sulfinic Acid

Copper-zinc superoxide dismutase (SOD) is considered one of the most important mammalian antioxidant defenses and plays a relevant role due to its main function in catalyzing the dismutation of superoxide anion to oxygen and hydrogen peroxide. However, interaction between SOD and H2O2 produced a strong copper-bound oxidant (Cu(II)•OH) that seems able to contrast the self-inactivation of the enzyme or oxidize other molecules through its peroxidase activity. The bicarbonate presence enhances the peroxidase activity and produces the carbonate anion radical (CO3•-). CO3•- is a freely diffusible reactive species capable of oxidizing several molecules that are unwieldy to access into the reactive site of the enzyme. Cu(II)•OH oxidizes bicarbonate to the CO3•-, which spreads out of the binding site and oxidizes hypotaurine and cysteine sulfinic acid to the respective sulfonates through an efficient reaction. These findings suggest a defense role for sulfinates against the damage caused by CO3•- . The effect of hypotaurine and cysteine sulfinic acid on the CO3•--mediated oxidation of the peroxidase probe ABTS to ABTS cation radical (ABTS•+) has been studied. Both sulfinates are able to inhibit the oxidation of ABTS mediated by CO3•-. The effect of hypotaurine and cysteine sulfinic acid against SOD inactivation by H2O2 (~42% protection of enzyme activity) has also been investigated. Interestingly, hypotaurine and cysteine sulfinic acid partially avoid the H2O2-mediated SOD inactivation, suggesting that the two sulfinates may have access to the SOD reactive site and preserve it by reacting with the copper-bound oxidant. In this way hypotaurine and cysteine sulfinic acid not only intercept CO3•- which could move out from the reactive site and cause oxidative damage, but also prevents the inactivation of SOD.

Increased N-Acetyltaurine in the Skeletal Muscle After Endurance Exercise in Rat

Taurine is metabolized to a novel metabolite, N-acetyltaurine (NAT), through N-acetylation with acetate. Furthermore, NAT production increases when the endogenous production of acetate is elevated in some situations, such as alcohol catabolism and endurance exercise. We have previously reported that both the serum concentration and urinary excretion of NAT from humans were increased after endurance exercise, and that NAT was secreted by cultured skeletal muscle cells exposed to both acetate and taurine. The present study evaluated the hypothesis that NAT is synthesized in the skeletal muscle after endurance exercise. Normal rats were loaded to a transient treadmill running until exhaustion. Serum, skeletal muscle, and liver were collected immediately after the exercise. The NAT concentration in the plasma and in the soleus muscle from the exercised rats was significantly increased compared to that in the samples from the sedentary control rats. There was a significant positive correlation in the NAT concentration between the plasma and soleus muscle. The NAT concentration in the liver was unchanged after the endurance exercise. These results confirm that the significantly increased NAT in both the serum and urine after endurance exercise is derived from NAT synthesis in the skeletal muscle.

The Interaction of Hypotaurine and Other Sulfinates with Reactive Oxygen and Nitrogen Species: A Survey of Reaction Mechanisms

Considerable strides have been made in understanding the oxidative mechanisms involved in the final steps of the cysteine pathway leading to taurine. The oxidation of sulfinates, hypotaurine and cysteine sulfinic acid, to the respective sulfonates, taurine and cysteic acid, has never been associated with any specific enzyme. Conversely, there is strong evidence that in vivo formation of taurine and cysteic acid is the result of sulfinate interaction with a variety of biologically relevant oxidants. In the last decade, many experiments have been performed to understand whether peroxynitrite, nitrogen dioxide and carbonate radical anion could be included in the biologically relevant reactive species capable of oxidizing sulfinates. Thanks to this work, it has been possible to highlight two possible reaction mechanisms (direct and indirect reaction) of sulfinates with reactive oxygen and nitrogen species.The sulfinates oxidation, mediated by peroxynitrite, is an example of both reaction mechanisms: through a two-electron-direct-reaction with peroxynitrite or through a one-electron-indirect-transfer reaction. In the indirect mechanism, the peroxynitrite homolysis releases hydroxyl and nitrogen dioxide radical and in addition the degradation of short-lived adduct formed by peroxynitrite and CO2 can generate carbonate radical anion. The reaction of hypotaurine and cysteine sulfinic acid with peroxynitrite-derived radicals is accompanied by extensive oxygen uptake with the generation of transient intermediates, which can begin a reaction by an oxygen-dependent mechanism with the sulfonates, taurine, and cysteic acid as final products. Due to pulse radiolysis studies, it has been shown that transient sulfonyl radicals (RSO2•) have been produced during the oxidation of both sulfinates by one-electron transfer reaction.The purpose is to analyze all the aspects of the reactive mechanism in the sulfinic group oxidation of hypotaurine and cysteine sulfinic acid through the results obtained from our laboratory in recent years.

A Proteomic Approach to Study the Effect of Thiotaurine on Human Neutrophil Activation

Thiotaurine, a thiosulfonate related to taurine and hypotaurine, is formed by a metabolic process from cystine and generated by a transulfuration reaction between hypotaurine and thiocysteine. Thiotaurine can produce hydrogen sulfide (H2S) from its sulfane sulfur moiety. H2S is a gaseous signaling molecule which can have regulatory roles in inflammatory process. In addition, sulfane sulfur displays the capacity to reversibly bind to other sulfur atoms. Thiotaurine inhibits PMA-induced activation of human neutrophils, and hinders neutrophil spontaneous apoptosis. Here, we present the results of a proteomic approach to study the possible effects of thiotaurine at protein expression level. Proteome analysis of human neutrophils has been performed comparing protein extracts of resting or PMA-activated neutrophils in presence or in absence of thiotaurine. In particular, PMA-stimulated neutrophils showed high level of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) expression compared to the level of the same glycolytic enzyme in the resting neutrophils. Conversely, decreased expression of GAPDH has been observed when human neutrophils were incubated with 1 mM thiotaurine before activation with PMA. This result, confirmed by Western blot analysis, suggests again that thiotaurine shows a bioactive role in the mechanisms underlying the inflammatory process, influencing the energy metabolism of activated leukocytes and raises the possibility that thiotaurine, acting as a sulfur donor, could modulate neutrophil activation via persulfidation of target proteins, such as GAPDH.

The Effect of Taurine and Its Immediate Homologs on Diabetes-Induced Oxidative Stress in the Brain and Spinal Cord of Rats

This study has examined the acute effects of taurine (TAU) and of its two immediate homologs aminomethanesulfonic acid (AMSA) and homotaurine (HTAU) on the oxidative stress that develops in the brain of rats as a result of type 2 diabetes mellitus. Male Sprague-Dawley rats, 220-225 g in weight, were divided into groups of 6 each, and treated with a single intraperitoneal (i.p.) dose of streptozotocin (STZ) in 10 mM citrate buffer pH 4.5 (60 mg/kg). The treatment compound (AMSA, HTAU or TAU) was administered by the i.p. route in two equal doses (1.2 mM/kg each) at 75 and 45 min before STZ. Control rats received only 10 mM citrate buffer pH 4.5 or only STZ by the i.p. route. The rats were sacrificed at 24 h after a dosing with STZ under general anesthesia, and their brains and spinal cords collected by the freeze clamp technique. A portion of brain, of a brain area (cerebellum, cortex, brain stem) or of spinal cord from each animal was extracted into 0.1 M PBS pH 7.4, and the extract was used for the assay of malondialdehyde (MDA), nitric oxide (NO), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD). An extract for the assay of the reduced (GSH) and disulfide (GGSG) forms of glutathione was prepared in similar manner but using 2% metaphosphoric acid plus 0.1 M PBS pH 8.0 as the extracting medium. Diabetes was found to markedly increase the formation of MDA (by 160-202%), NO (by 138-313%) and GSSG (by 103-241%), and to lower the values of GSH (by 57-65%), GSH/GSSG ratio (79-89%) and activities of CAT (by 61-69%), GPx (by 52-66%) and SOD (by 55-68%) in the brain, brain areas and spinal cord relative to corresponding control values (all at p < 0.001). These effects were reduced to values that were generally at least one-half of those seen in untreated diabetic rats, with TAU providing a greater attenuation of the formation of MDA and NO, an about similar action on the depletion of GSH, and a lower action on the decrease in the GSH/GSSG ratio caused by diabetes than either AMSA or HMTAU. In contrast AMSA and HMTAU were about equipotent with each other and more potent than TAU in preventing the loss of antioxidant enzyme activities associated with diabetes. In short, pretreating diabetic rats with AMSA, HMTAU or TAU is found to protect the brain against changes in biochemical parameters indicative of oxidative stress, with potency differences among the test compounds varying within a narrow range.

Diagnosis and Pharmacotherapy of Alcohol Use Disorder: A Review

Importance

Alcohol consumption is associated with 88 000 US deaths annually. Although routine screening for heavy alcohol use can identify patients with alcohol use disorder (AUD) and has been recommended, only 1 in 6 US adults report ever having been asked by a health professional about their drinking behavior. Alcohol use disorder, a problematic pattern of alcohol use accompanied by clinically significant impairment or distress, is present in up to 14% of US adults during a 1-year period, although only about 8% of affected individuals are treated in an alcohol treatment facility.

Observations

Four medications are approved by the US Food and Drug Administration to treat AUD: disulfiram, naltrexone (oral and long-acting injectable formulations), and acamprosate. However, patients with AUD most commonly receive counseling. Medications are prescribed to less than 9% of patients who are likely to benefit from them, given evidence that they exert clinically meaningful effects and their inclusion in clinical practice guidelines as first-line treatments for moderate to severe AUD. Naltrexone, which can be given once daily, reduces the likelihood of a return to any drinking by 5% and binge-drinking risk by 10%. Randomized clinical trials also show that some medications approved for other indications, including seizure disorder (eg, topiramate), are efficacious in treating AUD. Currently, there is not sufficient evidence to support the use of pharmacogenetics to personalize AUD treatments.

Conclusions and Relevance

Alcohol consumption is associated with a high rate of morbidity and mortality, and heavy alcohol use is the major risk factor for AUD. Simple, valid screening methods can be used to identify patients with heavy alcohol use, who can then be evaluated for the presence of an AUD. Patients receiving a diagnosis of the disorder should be given brief counseling and prescribed a first-line medication (eg, naltrexone) or referred for a more intensive psychosocial intervention.

Cysteine dioxygenase is essential for mouse sperm osmoadaptation and male fertility

Sperm entering the epididymis are immotile and cannot respond to stimuli that will enable them to fertilize. The epididymis is a highly complex organ, with multiple histological zones and cell types that together change the composition and functional abilities of sperm through poorly understood mechanisms. Sperm take up taurine during epididymal transit, which may play antioxidant or osmoregulatory roles. Cysteine dioxygenase (CDO) is a critical enzyme for taurine synthesis. A previous study reported that male CDO-/- mice exhibit idiopathic infertility, prompting us to investigate the functions of CDO in male fertility. Immunoblotting and quantitative reverse transcription-polymerase chain reaction analysis of epididymal segments showed that androgen-dependent CDO expression was highest in the caput epididymidis. CDO-/- mouse sperm demonstrated a severe lack of in vitro fertilization ability. Acrosome exocytosis and tyrosine phosphorylation profiles in response to stimuli were normal, suggesting normal functioning of pathways associated with capacitation. CDO-/- sperm had a slight increase in head abnormalities. Taurine and hypotaurine concentrations in CDO-/- sperm decreased in the epididymal intraluminal fluid and sperm cytosol. We found no evidence of antioxidant protection against lipid peroxidation. However, CDO-/- sperm exhibited severe defects in volume regulation, swelling in response to the relatively hypo-osmotic conditions found in the female reproductive tract. Our findings suggest that epididymal CDO plays a key role in post-testicular sperm maturation, enabling sperm to osmoregulate as they transition from the male to the female reproductive tract, and provide new understanding of the compartmentalized functions of the epididymis.

Catheter lock solutions: it's time for a change

In recent years, the number of patients on hemodialysis (HD) with central vascular catheters (CVCs) has grown. However, CVC use is often associated with an important risk for catheter related bloodstream infections (CRBI) and inadequate dialysis due to flow problems. In this study, we reviewed alternative solutions to heparin for locking HD CVCs. Several experiences have demonstrated that trisodium citrate (TSC) (30–47%), citrate (4%) and taurolidine (1.35%) solutions are effective and safe for the prevention of CRBI, while heparin stimulates biofilm formation. High citrate (47%) concentrations can also provide significant advantages in reducing catheter clotting, but controlled studies with larger populations are necessary to confirm and to extend the use of such solutions in clinical practice. Side effects with high sodium citrate concentrations have been reported only immediately after locking, the symptoms are probably caused by a temporary drop in ionized calcium and magnesium, but it is evident that these solutions should only be used by skilled and authorized personnel, with a rigorous protocol.

Taurine as a water structure breaker and protein stabilizer

The enhancing effect on the water structure has been confirmed for most of the osmolytes exhibiting both stabilizing and destabilizing properties in regard to proteins. The presented work concerns osmolytes, which should be classified as "structure breaking" solutes: taurine and N,N,N-trimethyltaurine (TMT). Here, we combine FTIR spectroscopy, DSC calorimetry and DFT calculations to gain an insight into the interactions between osmolytes and two proteins: lysozyme and ubiquitin. Despite high structural similarity, both osmolytes exert different influence on protein stability: taurine is a stabilizer, TMT is a denaturant. We show also that taurine amino group interacts directly with the side chains of proteins, whereas TMT does not interact with proteins at all. Although two solutes weaken on average the structure of the surrounding water, their hydration spheres are different. Taurine is surrounded by two populations of water molecules: bonded with weak H-bonds around sulfonate group, and strongly bonded around amino group. The strong hydrogen-bonded network of water molecules around the amino group of taurine further improves properties of enhanced protein hydration sphere and stabilizes the native protein form. Direct interactions of this group with surface side chains provide a proper orientation of taurine and prevents the [Formula: see text] group from negative influence. The weakened [Formula: see text] hydration sphere of TMT breaks up the hydrogen-bonded network of water around the protein and destabilizes it. However, TMT at low concentration stabilize both proteins to a small extent. This effect can be attributed to an actual osmophobic effect which is overcome if the concentration increases.

Evaluation of N-acetyltaurine as an ethanol marker in human blood

To investigate the potential of N-acetyltaurine (NAcT) in blood as a biomarker for alcohol uptake, a previously published LC-MS/MS method for urine was modified to simultaneously detect NAcT and ethyl glucuronide (EtG). The method was applied in a drinking study and by analyzing 147 forensic case samples. In the drinking study, contrary to EtG, NAcT proved to be an endogenous substance, which was present at 22 ± 7 ng/mL (13-31 ng/mL) in the blood after 2 weeks of abstinence. A moderate increase in NAcT to 40 ± 10 ng/mL (27-57 ng/mL) was observed after drinking. Within 24 h, the NAcT concentrations declined to starting concentrations in seven out of eight subjects. Peak EtG concentrations (c¯_max) of 445 ± 101 ng/mL (278-662 ng/mL) were reached. While EtG in blood can be used to detect alcohol consumption even if ethanol is already eliminated, some of the maximum NAcT concentrations after a single ethanol dose were in the range of endogenous levels detected prior to the start of drinking in other subjects. In the 147 blood samples, the following concentrations were found: blood alcohol concentration (BAC): 1.22 ± 0.95 g/kg (0-3.46 g/kg); NAcT: 37.8 ± 18.4 ng/mL (12.1-109 ng/mL); EtG: 1149 ± 1121 ng/mL (0-5950 ng/mL). ROC curve analysis for BAC thresholds at 0.8 and 1.6 g/kg were performed for EtG and NAcT. Due to the presence of endogenous NAcT levels resulting in a lower sensitivity and selectivity when compared to EtG, and due to a minor increase in concentration after alcohol uptake, the usefulness of NAcT as an alcohol biomarker in blood is very limited.