Thiamine prevents obesity and obesity-associated metabolic disorders in OLETF rats

[Effect of a multivitamin on insulin resistance, inflammation, and oxidative stress in a Wistar rat model of induced obesity]

Introduction

Introduction: excessive accumulation of adipose tissue is accompanied by alterations in the inflammatory state and increased oxidative stress, and these variables are associated with insulin resistance and increased glucose and insulin levels. On the other hand, vitamins and minerals reinforce the antioxidant and inflammatory capacity, for this reasons we propose that they could contribute to the control of insulin resistance, glucose and lipid metabolism in a rat model of obesity. Objective: to analyze the effect of a multivitamin supplement on markers of insulin resistance, inflammation, and oxidative stress in obese rats on a cafeteria diet. Methods: thirty-five 28-day-old male Wistar rats were randomly divided into four groups: 1, standard diet control; 2, standard diet plus multivitamin; 3, obese on a cafeteria diet; and 4, obese on a cafeteria diet plus multivitamin. After the treatments, glucose levels, HbA1c, insulin, TNF-α, IL-6, oxidative stress and lipid profile were analyzed by colorimetric methods, as well as the percentage of adipose tissue, Homeostasis Model Assessment (HOMA) index y Quantitative Insulin Sensitivity Check Index (QUICKI). Results: multivitamin supplementation significantly decreased visceral adipose tissue, HOMA index, glucose, HbA1c, oxidant stress, and inflammatory markers in the obese plus multivitamin rat group, compared with the obese cafeteria diet rat group and the standard diet rat control group. However, the group that was administered only the multivitamin without the cafeteria diet had increased levels of total adipose tissue, glucose, and oxidative stress, as well as the QUICKI index relative to the control group with the standard diet. Conclusion: co-administration of a multivitamin supplement may improve insulin sensitivity, glucose metabolism and lipid profile; strengthen antioxidant status; and decrease inflammation during weight gain. However, it was not expected that added sugars in multivitamin supplement can also increase total adipose tissue, oxidative stress and glucose levels, so it is suggested to use sugar-free multivitamins in the future.

Extracellular thiamine concentration influences thermogenic competency of differentiating neck area-derived human adipocytes

Introduction

Brown adipose tissue (BAT) dissipates energy in the form of heat majorly via the mitochondrial uncoupling protein 1 (UCP1). The activation of BAT, which is enriched in the neck area and contains brown and beige adipocytes in humans, was considered as a potential therapeutic target to treat obesity. Therefore, finding novel agents that can stimulate the differentiation and recruitment of brown or beige thermogenic adipocytes are important subjects for investigation. The current study investigated how the availability of extracellular thiamine (vitamin B1), an essential cofactor of mitochondrial enzyme complexes that catalyze key steps in the catabolism of nutrients, affects the expression of thermogenic marker genes and proteins and subsequent functional parameters during ex vivo adipocyte differentiation.

Methods

We differentiated primary human adipogenic progenitors that were cultivated from subcutaneous (SC) or deep neck (DN) adipose tissues in the presence of gradually increasing thiamine concentrations during their 14-day differentiation program. mRNA and protein expression of thermogenic genes were analyzed by RT-qPCR and western blot, respectively. Cellular respiration including stimulated maximal and proton-leak respiration was measured by Seahorse analysis.

Results

Higher thiamine levels resulted in increased expression of thiamine transporter 1 and 2 both at mRNA and protein levels in human neck area-derived adipocytes. Gradually increasing concentrations of thiamine led to increased basal, cAMP-stimulated, and proton-leak respiration along with elevated mitochondrial biogenesis of the differentiated adipocytes. The extracellular thiamine availability during adipogenesis determined the expression levels of UCP1, PGC1a, CKMT2, and other browning-related genes and proteins in primary SC and DN-derived adipocytes in a concentration-dependent manner. Providing abundant amounts of thiamine further increased the thermogenic competency of the adipocytes.

Discussion

Case studies in humans reported that thiamine deficiency was found in patients with type 2 diabetes and obesity. Our study raises the possibility of a novel strategy with long-term thiamine supplementation, which can enhance the thermogenic competency of differentiating neck area-derived adipocytes for preventing or combating obesity.

Availability of abundant thiamine determines efficiency of thermogenic activation in human neck area derived adipocytes

Brown/beige adipocytes express uncoupling protein-1 (UCP1) that enables them to dissipate energy as heat. Systematic activation of this process can alleviate obesity. Human brown adipose tissues are interspersed in distinct anatomical regions including deep neck. We found that UCP1 enriched adipocytes differentiated from precursors of this depot highly expressed ThTr2 transporter of thiamine and consumed thiamine during thermogenic activation of these adipocytes by cAMP which mimics adrenergic stimulation. Inhibition of ThTr2 led to lower thiamine consumption with decreased proton leak respiration reflecting reduced uncoupling. In the absence of thiamine, cAMP-induced uncoupling was diminished but restored by thiamine addition reaching the highest levels at thiamine concentrations larger than present in human blood plasma. Thiamine is converted to thiamine pyrophosphate (TPP) in cells; the addition of TPP to permeabilized adipocytes increased uncoupling fueled by TPP-dependent pyruvate dehydrogenase. ThTr2 inhibition also hampered cAMP-dependent induction of UCP1, PGC1a, and other browning marker genes, and thermogenic induction of these genes was potentiated by thiamine in a concentration dependent manner. Our study reveals the importance of amply supplied thiamine during thermogenic activation in human adipocytes which provides TPP for TPP-dependent enzymes not fully saturated with this cofactor and by potentiating the induction of thermogenic genes.

Bee bread attenuates high fat diet induced renal pathology in obese rats via modulation of oxidative stress, downregulation of NF-kB mediated inflammation and Bax signalling

CONTEXT

Global prevalence of obesity is increasing.

OBJECTIVE

To study the effect of bee bread (BB) on serum renal function parameters, oxidative stress, inflammatory and B-cell associated protein X (Bax) in the kidneys of high fat diet (HFD) obese rats.

METHODS

Thirty-six male Sprague Dawley rats were used. Control: received rat diet and water (1 mL/kg); HFD group: received HFD and water (1 mL/kg): bee bread (BB) preventive or orlistat preventive: received HFD and BB (0.5 g/kg) or HFD and orlistat (10 mg/kg); BB or orlistat treatment: received BB (0.5 g/kg) or orlistat (10 mg/kg).

RESULTS

HFD group had increased body weight, Body Mass Index, Lee Obesity Indices, kidney weights, malondialdehyde, inflammatory markers, Bax; decreased glutathione peroxidase, glutathione-S-transferase, superoxide dismutase, total antioxidant activity, no differences (p > .05) in food intakes, serum creatinine, sodium, potassium, chloride, catalase compared to control.

CONCLUSION

BB modulated most of these parameters, as corroborated by histology.

B Vitamins Supplementation Can Improve Cognitive Functions and May Relate to the Enhancement of Transketolase Activity in A Rat Model of Cognitive Impairment Associated with High-fat Diets

OBJECTIVE

To determine whether B vitamin treatment was sufficient to reduce cognitive impairment associated with high-fat diets in rats and to modulate transketolase (TK) expression and activity.

METHODS

To test this, we separated 50 rats into five groups that were either fed a standard chow diet (controls) or a high-fat diet (experimental groups H0, H1, H2, and H3). H0 group animals received no additional dietary supplementation, while H1 group animals were administered 100 mg/kg body weight (BW) thiamine, 100 mg/kg BW riboflavin, and 250 mg/kg BW niacin each day, and group H2 animals received daily doses of 100 mg/kg BW pyridoxine, 100 mg/kg BW cobalamin, and 5 mg/kg BW folate. Animals in the H3 group received the B vitamin regimens administered to both H1 and H2 each day.

RESULTS

Over time, group H0 exhibited greater increases in BW and fat mass relative to other groups. When spatial and memory capabilities in these animals were evaluated via conditioned taste aversion (CTA) and Morris Water Maze (MWM), we found B vitamin treatment was associated with significant improvements relative to untreated H0 controls. Similarly, B vitamin supplementation was associated with elevated TK expression in erythrocytes and hypothalamus of treated animals relative to those in H0 (P<0.05).

CONCLUSION

Together, these findings suggest B vitamin can modulate hypothalamic TK activity to reduce the severity of cognitive deficits in a rat model of obesity. As such, B vitamin supplementation may be a beneficial method for reducing cognitive dysfunction in clinical settings associated with high-fat diets.

Identification of strong candidate genes for backfat and intramuscular fatty acid composition in three crosses based on the Iberian pig

Meat quality has an important genetic component and can be modified by the fatty acid (FA) composition and the amount of fat contained in adipose tissue and muscle. The present study aimed to find genomic regions associated with the FA composition in backfat and muscle (longissimus dorsi) in 439 pigs with three different genetic backgrounds but having the Iberian breed in common. Genome-wide association studies (GWAS) were performed between 38,424 single-nucleotide polymorphisms (SNPs) covering the pig genome and 60 phenotypic traits related to backfat and muscle FA composition. Nine significant associated regions were found in backfat on the Sus scrofa chromosomes (SSC): SSC1, SSC2, SSC4, SSC6, SSC8, SSC10, SSC12, and SSC16. For the intramuscular fat, six significant associated regions were identified on SSC4, SSC13, SSC14, and SSC17. A total of 52 candidate genes were proposed to explain the variation in backfat and muscle FA composition traits. GWAS were also reanalysed including SNPs on five candidate genes (ELOVL6, ELOVL7, FADS2, FASN, and SCD). Regions and molecular markers described in our study may be useful for meat quality selection of commercial pig breeds, although several polymorphisms were breed-specific, and further analysis would be needed to evaluate possible causal mutations.

Differential fecal microbiota are retained in broiler chicken lines divergently selected for fatness traits

Our study combined 16S rRNA-pyrosequencing and whole genome sequencing to analyze the fecal metagenomes of the divergently selected lean (LL) and fat (FL) line chickens. Significant structural differences existed in both the phylogenic and functional metagenomes between the two chicken lines. At phylum level, the FL group had significantly less Bacteroidetes. At genus level, fourteen genera of different relative abundance were identified, with some known short-chain fatty acid producers (including Subdoligranulum, Butyricicoccus, Eubacterium, Bacteroides, Blautia) and a potentially pathogenic genus (Enterococcus). Redundancy analysis identified 190 key responsive operational taxonomic units (OTUs) that accounted for the structural differences between the phylogenic metagenome of the two groups. Four Cluster of Orthologous Group (COG) categories (Amino acid transport and metabolism, E; Nucleotide transport and metabolism, F; Coenzyme transport and metabolism, H; and Lipid transport and metabolism, I) were overrepresented in LL samples. Fifteen differential metabolic pathways (Biosynthesis of amino acids, Pyruvate metabolism, Nitrotoluene degradation, Lipopolysaccharide biosynthesis, Peptidoglycan biosynthesis, Pantothenate and CoA biosynthesis, Glycosaminoglycan degradation, Thiamine metabolism, Phosphotransferase system, Two-component system, Bacterial secretion system, Flagellar assembly, Bacterial chemotaxis, Ribosome, Sulfur relay system) were identified. Our data highlighted interesting variations between the gut metagenomes of these two chicken lines.

Effects of Fatty Liver Induced by Excess Orotic Acid on B-Group Vitamin Concentrations of Liver, Blood, and Urine in Rats

Fatty liver is caused when rats are given orotic acid of the pyrimidine base in large quantities. The lack of B-group vitamins suppresses the biosynthesis of fatty acids. We investigated how orotic acid-induced fatty liver affects the concentrations of liver, blood, and urine B-group vitamins in rats. The vitamin B6 and B12 concentrations of liver, blood, and urine were not affected by orotic acid-induced fatty liver. Vitamin B2 was measured only in the urine, but was unchanged. The liver, blood, and urine concentrations of niacin and its metabolites fell dramatically. Niacin and its metabolites in the liver, blood, and urine were affected as expected. Although the concentrations of vitamin B1, pantothenic acid, folate, and biotin in liver and blood were decreased by orotic acid-induced fatty liver, these urinary excretion amounts showed a specific pattern toward increase. Generally, as for the typical urinary excretion of B-group vitamins, these are excreted when the body is saturated. However, the ability to sustain vitamin B1, pantothenic acid, folate, and biotin decreased in fatty liver, which is hypothesized as a specific phenomenon. This metabolic response might occur to prevent an abnormally increased biosynthesis of fatty acids by orotic acid.

The nutritional composition and anti-obesity effects of an herbal mixed extract containing Allium fistulosum and Viola mandshurica in high-fat-diet-induced obese mice

Background

In traditional oriental medicine, A. fistulosum and V. mandshurica are considered to be effective in promoting blood circulation. Therefore, in this study, we investigated whether a solution containing both A. fistulosum and V. mandshurica (AFE + VME) extracts has synergistic effects on the treatment of hyperlipidemia and obesity.

Methods

Anti-obesity effects of an herbal extract containing Allium fistulosum and Viola mandshurica (AFE + VME) were investigated in high-fat diet (HFD)-induced obese mice. AFE + VME was orally administrated to mice with the HFD at a dose of 200 mg/kg/day for 8 weeks. We observed the effects of mixed extract on body weight, fat mass, serum lipid levels, and mRNA expression levels of lipid metabolism-related genes in the adipose tissue of mice.

Results

The nutritional analysis revealed that this mixed extract is high in carbohydrate (72.2 g/100 g) and protein (11.5 g/100 g); low in fat (1.7 g/100 g); rich in vitamins E (4.8 mg/100 g), B₁ (14.8 mg/100 g), B₂ (1.0 mg/100 g), niacin (7.9 mg/100 g), and folic acid (1.57 mg/100 g); and rich in minerals such as calcium (600 mg/100 g), iron (106.1 mg/100 g), and zinc (5.8 mg/100 g). The oral administration of AFE + VME in obese mice reduced body weight, tissue weight, adipocyte size, and lipid accumulation in the liver compared with HFD control mice. AFE + VME also decreased serum triglyceride, total cholesterol, and leptin concentrations. Furthermore, AFE + VME markedly increased the mRNA expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), uncoupling protein-2 (UCP-2), and adiponectin and decreased leptin expression in the epididymal white adipose tissue. Our results suggest that the extract containing A. fistulosum and V. mandshurica improved lipid metabolism via the up-regulation of PPAR-γ, UCP-2, and adiponectin expression and the down-regulation of leptin in HFD-induced obese mice.

Conclusions

Therefore, the extract containing Allium fistulosum and Viola mandshurica may be a potentially effective therapy for obesity and its related metabolic disorders such as hyperlipidemia and insulin resistance.

Multivitamin restriction increases adiposity and disrupts glucose homeostasis in mice

A strong association between obesity and low plasma concentrations of vitamins has been widely reported; however, the causality of this relationship is still not established. Our goal was to evaluate the impact of a multivitamin restriction diet (MRD) on body weight, adiposity and glucose homeostasis in mice. The mice were given a standard diet or a diet containing 50 % of the recommended vitamin intake (MRD) for 12 weeks. At the end of the experiment, total body weight was 6 % higher in MRD animals than in the control group, and the adiposity of the MRD animals more than doubled. The HOMA-IR index of the MRD animals was significantly increased. The adipose tissue of MRD animals had lower expression of mRNA encoding adiponectin and Pnpla2 (47 and 32 %, respectively) and 43 % higher leptin mRNA levels. In the liver, the mRNA levels of Pparα and Pgc1α were reduced (29 and 69 %, respectively) in MRD mice. Finally, the level of β-hydroxybutyrate, a ketonic body reflecting fatty acid oxidation, was decreased by 45 % in MRD mice. Our results suggest that MRD promotes adiposity, possibly by decreasing adipose tissue lipolysis and hepatic β-oxidation. These results could highlight a possible role of vitamin deficiency in the etiology of obesity and associated disorders.

Metabolic Benefits of Six-month Thiamine Supplementation in Patients With and Without Diabetes Mellitus Type 2

Thiamine deficiency has been documented to be prevalent in patients with diabetes mellitus, and correction of thiamine deficiency in this population may provide beneficial effects in several cardiometabolic parameters, including prevention of impending complications secondary to chronic hyperglycemia. In this interventional study, we aim to determine whether thiamine supplementation is associated with cardiometabolic improvements in patients with diabetes mellitus type 2 (DMT2). A total of 86 subjects (60 DMT2 and 26 age- and BMI-matched controls) were included and were given thiamine supplements (100 mg/day) for six months. Anthropometrics and metabolic profiles were measured routinely. Serum thiamine and its derivatives were measured using high performance liquid chromatography. In all groups, there was a significant decrease in total cholesterol after three months (p = 0.03) as well as in HDL cholesterol after six months of thiamine supplementation (p = 0.009). Significant improvements were also observed in the mean serum levels of creatinine (p = 0.001), as well as thiamine and its derivatives in both serum and urinary levels across follow-up visits (p-values 0.002 and <0.001, respectively). In the DMT2 group, improvements were observed in lipid profile (mean serum LDL and total cholesterol with p-values 0.008 and 0.006, respectively), serum thiamine (p < 0.001), TMP (p < 0.001), TDP (p < 0.001), urinary thiamine (p < 0.001) and serum creatinine (p < 0.001). Thiamine supplementation is a promising adjuvant therapy for patients with DMT2. Longer clinical trials are needed to determine its protective effect in DMT2 complications.

Liver aging and pseudocapillarization in a Werner syndrome mouse model

Werner syndrome is a progeric syndrome characterized by premature atherosclerosis, diabetes, cancer, and death in humans. The knockout mouse model created by deletion of the RecQ helicase domain of the mouse Wrn homologue gene (Wrn(∆hel/∆hel)) is of great interest because it develops atherosclerosis and hypertriglyceridemia, conditions associated with aging liver and sinusoidal changes. Here, we show that Wrn(∆hel/∆hel) mice exhibit increased extracellular matrix, defenestration, decreased fenestration diameter, and changes in markers of liver sinusoidal endothelial cell inflammation, consistent with age-related pseudocapilliarization. In addition, hepatocytes are larger, have increased lipofuscin deposition, more frequent nuclear morphological anomalies, decreased mitochondria number, and increased mitochondrial diameter compared to wild-type mice. The Wrn(∆hel/∆hel) mice also have altered mitochondrial function and altered nuclei. Microarray data revealed that the Wrn(∆hel/∆hel) genotype does not affect the expression of many genes within the isolated hepatocytes or liver sinusoidal endothelial cells. This study reveals that Wrn(∆hel/∆hel) mice have accelerated typical age-related liver changes including pseudocapillarization. This confirms that pseudocapillarization of the liver sinusoid is a consistent feature of various aging models. Moreover, it implies that DNA repair may be implicated in normal aging changes in the liver.

Dietary nutrient intake and metabolic syndrome risk in Chinese adults: a case-control study

Background

Because human diets are composed of a wide variety of nutrients that may work synergistically to prevent or promote disease, assessing dietary nutrient intake status may be informative. The purpose of this study was to assess the dietary nutrient intake status of Chinese adults with metabolic syndrome (MetS) and to evaluate its possible role in MetS.

Methods

This case–control study was conducted from March 2010 to January 2011. A total of 123 patients with MetS and 135 controls participated in this study at the Health Examination Center of Heping District in Tianjin, China. Dietary intake was estimated by 24-h dietary recalls. We used principal component factor analysis to derive nutrient groups from 17 major nutrients. We examined the odds ratios and 95% confidence intervals using logistic regression models to test the relationship between tertiles of dietary nutrient pattern and MetS.

Results

There were 4 major dietary nutrient patterns in this study: “vitamin B group”, “protein and lipids”, “vitamin E and minerals”, and “antioxidant vitamins”. After adjustment for potential confounders, the highest tertile of the nutrient pattern factor score for the “vitamin B group” (odds ratio: 0.16; 95% confidence interval: 0.05–0.47) was negatively associated with MetS compared with the lowest tertiles. No relationships were found between other dietary nutrient patterns and MetS.

Conclusions

The “vitamin B group” pattern was inversely associated with MetS in Chinese adults. This finding supports the hypothesis that the “vitamin B group” pattern may have a potentially beneficial effect on the prevention of MetS.

High-fat diet induces dynamic metabolic alterations in multiple biological matrices of rats

Obesity is a condition resulting from the interactions of individual biology and environmental factors causing multiple complications. To understand the system's metabolic changes associated with the obesity development and progression, we systematically analyzed the dynamic metabonomic changes induced by a high-fat diet (HFD) in multiple biological matrices of rats using NMR and GC-FID/MS techniques. Clinical chemistry and histopathological data were obtained as complementary information. We found that HFD intakes caused systematic metabolic changes in blood plasma, liver, and urine samples involving multiple metabolic pathways including glycolysis, TCA cycle, and gut microbiota functions together with the metabolisms of fatty acids, amino acids, choline, B-vitamins, purines, and pyrimidines. The HFD-induced metabolic variations were detectable in rat urine a week after HFD intake and showed clear dependence on the intake duration. B-vitamins and gut microbiota played important roles in the obesity development and progression together with changes in TCA cycle intermediates (citrate, α-ketoglutarate, succinate, and fumarate). 83-day HFD intakes caused significant metabolic alterations in rat liver highlighted with the enhancements in lipogenesis, lipid accumulation and lipid oxidation, suppression of glycolysis, up-regulation of gluconeogenesis and glycogenesis together with altered metabolisms of choline, amino acids and nucleotides. HFD intakes reduced the PUFA-to-MUFA ratio in both plasma and liver, indicating the HFD-induced oxidative stress. These findings provided essential biochemistry information about the dynamic metabolic responses to the development and progression of HFD-induced obesity. This study also demonstrated the combined metabonomic analysis of multiple biological matrices as a powerful approach for understanding the molecular basis of pathogenesis and disease progression.

Regulation of Phosphatidylethanolamine Homeostasis&#8212;The Critical Role of CTP:Phosphoethanolamine Cytidylyltransferase (Pcyt2)

Phosphatidylethanolamine (PE) is the most abundant lipid on the protoplasmatic leaflet of cellular membranes. It has a pivotal role in cellular processes such as membrane fusion, cell cycle regulation, autophagy, and apoptosis. CTP:phosphoethanolamine cytidylyltransferase (Pcyt2) is the main regulatory enzyme in de novo biosynthesis of PE from ethanolamine and diacylglycerol by the CDP-ethanolamine Kennedy pathway. The following is a summary of the current state of knowledge on Pcyt2 and how splicing and isoform specific differences could lead to variations in functional properties in this family of enzymes. Results from the most recent studies on Pcyt2 transcriptional regulation, promoter function, autophagy, and cell growth regulation are highlighted. Recent data obtained from Pcyt2 knockout mouse models is also presented, demonstrating the essentiality of this gene in embryonic development as well as the major physiological consequences of deletion of one Pcyt2 allele. Those include development of symptoms of the metabolic syndrome such as elevated lipogenesis and lipoprotein secretion, hypertriglyceridemia, liver steatosis, obesity, and insulin resistance. The objective of this review is to elucidate the nature of Pcyt2 regulation by linking its catalytic function with the regulation of lipid and energy homeostasis.

Uncovering the beginning of diabetes: the cellular redox status and oxidative stress as starting players in hyperglycemic damage

Early hyperglycemic insult can lead to permanent, cumulative damage that might be one of the earliest causes for a pre-diabetic situation. Despite this, the early phases of hyperglycemic exposure have been poorly studied. We have previously demonstrated that mitochondrial injury takes place early on upon hyperglycemic exposure. In this work, we demonstrate that just 1 h of hyperglycemic exposure is sufficient to induce increased mitochondrial membrane potential and generation. This is accompanied (and probably caused) by a decrease in the cells' NAD(+)/NADH ratio. Furthermore, we show that the modulation of the activity of parallel pathways to glycolysis can alter the effects of hyperglycemic exposure. Activation of the pentose phosphate pathway leads to diminished effects of glucose on the above parameters, either by removing glucose from glycolysis or by NADPH generation. We also demonstrate that the hexosamine pathway inhibition also leads to a decreased effect of excess glucose. So, this work demonstrates the need for increased focus of study on the reductive status of the cell as one of the most important hallmarks of initial hyperglycemic damage.

Adenosine thiamine triphosphate (AThTP) inhibits poly(ADP-ribose) polymerase-1 (PARP-1) activity

Overactivation of poly(ADP-ribose) polymerase-1 (PARP-1) has been demonstrated to result in various stress-related diseases, including diabetes mellitus. Deficiency of cellular nicotinamide adenine dinucleotide (NAD(+)) content, consumed by PARP-1 to add ADP-ribose moieties onto target proteins, contributes to pathophysiological conditions. Adenosine thiamine triphosphate (AThTP) exists in small amounts in mammals; however, the function(s) of this metabolite remains unresolved. The structure of AThTP resembles NAD(+). Recent experimental studies demonstrate beneficial impacts of high-dose thiamine treatment of diabetic complications. These findings have led us to hypothesize that AThTP may modulate the activity of PARP-1. We have chemically synthesized AThTP and evaluated the effect of AThTP on recombinant PARP-1 enzyme activity. AThTP inhibited the PARP-1 activity at 10 µM, and a structural model of the PARP-1-AThTP complex highlighted the AThTP binding site. The results provide new insights into the pharmacological importance of AThTP as an inhibitor of PARP-1.