Toxicokinetics of the Antidepressant Fluoxetine and Its Active Metabolite Norfluoxetine in Caenorhabditis elegans and Their Comparative Potency.

The nematode Caenorhabditis elegans is a valuable model for ecotoxicological research, yet limited attention has been given to understanding how it absorbs, distributes, metabolizes, and excretes chemicals. This is crucial for C. elegans because the organism is known to have strong uptake barriers that are known to be susceptible to potential confounding effects of the presence of Escherichia coli as a food source. One frequently studied compound in C. elegans is the antidepressant fluoxetine, which has an active metabolite norfluoxetine. In this study, we evaluated the toxicokinetics and relative potency of norfluoxetine and fluoxetine in chemotaxis and activity tests. Toxicokinetics experiments were conducted with varying times, concentrations of fluoxetine, and in the absence or presence of E. coli, simulated with a one-compartment model. Our findings demonstrate that C. elegans can take up fluoxetine and convert it into norfluoxetine. Norfluoxetine proved slightly more potent and had a longer elimination half-life. The bioconcentration factor, uptake, and elimination rate constants depended on exposure levels, duration, and the presence of E. coli in the exposure medium. These findings expand our understanding of toxicokinetic modeling in C. elegans for different exposure scenarios, underlining the importance of considering norfluoxetine formation in exposure and bioactivity assessments of fluoxetine.

Exposure to the mycotoxin deoxynivalenol reduces the transport of conjugated bile acids by intestinal Caco-2 cells.

Conjugated bile acids are synthesized in liver and subsequently secreted into the intestinal lumen from which they are actively reabsorbed and transported back to liver. The efficient enterohepatic circulation of conjugated bile acids is important to maintain homeostasis. The mycotoxin deoxynivalenol (DON) is a fungal secondary metabolite that contaminates cereal food. Upon human exposure, it can cause intestinal dysfunction. We explored the effects of DON exposure on the intestinal absorption of conjugated bile acids and the expression of bile acid transporters using an in vitro model based on Caco-2 cell layers grown in transwells. Our study shows that the transport rate of taurocholic acid (TCA) is decreased after 48-h pre-exposure of the Caco-2 cells to 2 µM DON, which is a realistic intestinal DON concentration. Exposure to DON downregulates expression of the genes coding for the apical sodium-dependent bile acid transporter (ASBT), the ileal bile acid-binding protein (IBABP) and the organic solute transporter α (OSTα), and it counteracts the agonist activity of Farnesoid X receptor (FXR) agonist GW4064 on these genes. In addition, the transport of ten taurine or glycine-conjugated bile acids in a physiological relevant mixture by the intestinal Caco-2 cell layers was decreased after pre-exposure of the cells to DON, pointing at a potential for DON-mediated accumulation of the conjugated bile acids at the intestinal luminal side. Together the results reveal that DON inhibits intestinal bile acid reabsorption by reducing the expression of bile acid transporters thereby affecting bile acid intestinal kinetics, leading to bile acid malabsorption in the intestine. Our study provides new insights into the hazards of DON exposure.

In vitro models to detect in vivo bile acid changes induced by antibiotics.

Bile acid homeostasis plays an important role in many biological activities through the bile-liver-gut axis. In this study, two in vitro models were applied to further elucidate the mode of action underlying reported in vivo bile acid changes induced by antibiotics (colistin sulfate, tobramycin, meropenem trihydrate, and doripenem hydrate). 16S rRNA analysis of rat fecal samples anaerobically incubated with these antibiotics showed that especially tobramycin induced changes in the gut microbiota. Furthermore, tobramycin was shown to inhibit the microbial deconjugation of taurocholic acid (TCA) and the transport of TCA over an in vitro Caco-2 cell layer used as a model to mimic intestinal bile acid reuptake. The effects induced by the antibiotics in the in vitro model systems provide novel and complementary insight explaining the effects of the antibiotics on microbiota and fecal bile acid levels upon 28-day in vivo treatment of rats. In particular, our results provide insight in the mode(s) of action underlying the increased levels of TCA in the feces upon tobramycin exposure. Altogether, the results of the present study provide a proof-of-principle on how in vitro models can be used to elucidate in vivo effects on bile acid homeostasis, and to obtain insight in the mode(s) of action underlying the effect of an antibiotic, in this case tobramycin, on bile acid homeostasis via effects on intestinal bile acid metabolism and reuptake.

Heavyweight Mesh Is Superior to Lightweight Mesh in Laparo-endoscopic Inguinal Hernia Repair: A Meta-analysis and Trial Sequential Analysis of Randomized Controlled Trials.

OBJECTIVE: This meta-analysis and trial sequential analysis aims to provide an update on the available randomized controlled trials (RCTs) and recommendations on using lightweight mesh (LWM) or heavyweight mesh (HWM) in laparo-endoscopic inguinal hernia repair. BACKGROUND: LWM might reduce chronic pain through improved mesh flexibility and less fibrosis formation. However, in laparo-endoscopic repair chronic pain is already rare and LWM raise concerns of higher recurrence rates. METHODS: A literature search was conducted in May 2019 in MEDLINE, Embase, and the Cochrane library for RCTs that compared lightweight (≤50 g/m2) and heavyweight (>70 g/m2) mesh in patients undergoing laparo-endoscopic surgery for uncomplicated inguinal hernias. Outcomes were recurrences, chronic pain, and foreign-body sensation. The level of evidence was assessed using GRADE. Risk ratios (RR) and 95% confidence intervals (CI) were calculated by random effect meta-analyses. Trial-sequential-analyses were subsequently performed. RESULTS: Twelve RCTs, encompassing 2909 patients (LWM 1490 vs HWM 1419), were included. The follow-up range was 3 to 60 months. Using LWM increased the recurrence risk (LWM 32/1571, HWM 13/1508; RR 2.21; CI 1.14-4.31), especially in nonfixated mesh direct repairs (LWM 13/180, HWM 1/171; RR 7.27; CI 1.33-39.73) and/or large hernia defects. No difference was determined regarding any pain (LWM 123/1362, HWM 127/1277; RR 0.79; CI 0.52-1.20), severe pain (LWM 3/1226, HWM 9/1079; RR 0.38; CI 0.11-1.35), and foreign-body sensation (LWM 100/1074, HWM 103/913; RR 0.94; CI 0.73-1.20). CONCLUSION: HWM should be used in laparo-endoscopic repairs of direct or large inguinal hernias to reduce recurrence rates. LWM provide no benefit in indirect hernias.

Influence of previous laparo-endoscopic inguinal hernia repair on performing radical prostatectomy: a nationwide survey among urological surgeons.

BACKGROUND: There is considerable demographic overlap of inguinal hernia patients and prostate cancer patients. Previous laparo-endoscopic inguinal hernia mesh repairs can complicate subsequent radical prostatectomies due to adhesions and distortion of anatomic planes. This study aims to assess the experience of urological surgeons on the safety and feasibility of performing radical prostatectomies after laparo-endoscopic inguinal hernia mesh repair. METHODS: For this cross-sectional study, an online 24 question survey was developed regarding the experience in performing a radical prostatectomy and pelvic lymph node dissection (PLND) with a prior preperitoneal inguinal hernia mesh repair. Between June 2016 and December 2017, the questionnaire was sent to all 68 urological surgeons performing radical prostatectomy in the Netherlands. RESULTS: The response rate of urological surgeons was 69% (n = 47). The majority (77%) of urological surgeons perform robot-assisted laparoscopic prostatectomies. A previous preperitoneal inguinal hernia repair was reported by 40% of urological surgeons in 10-30% of patients undergoing radical prostatectomy. Radical prostatectomy with prior preperitoneal inguinal hernia mesh repair is considered more difficult by 49%, predominantly because of (occasionally to always) experienced longer operating times (88.4%), increased blood loss (46.5%), difficult dissection of Retzius space (88.4%), nerve-sparing difficulties (32.6%), less adequate PLND (69.8%), and bladder- (16.3%) or peritoneal perforations (27.9%). Additionally, 11.6% had performed mesh explantation, 16.3% had aborted radical prostatectomies, and 35.7% experienced increased inguinal hernia recurrences after radical prostatectomies with prior preperitoneal inguinal hernia mesh repair. More experienced urological surgeons reported an increased difficulty for all outcomes. CONCLUSIONS: Laparo-endoscopic inguinal hernia mesh repair has a significant impact on performing a radical prostatectomy and PLND. Surgeons should postpone the inguinal hernia repair of patients in the workup for a radical prostatectomy, with the preferable option of performing the radical prostatectomy and inguinal hernia repair in the same procedure. Alternatively, a Lichtenstein repair can be performed.

Management of prolonged first stage of labour in a low-resource setting: lessons learnt from rural Malawi.

BACKGROUND: Caesarean sections without medical indication cause substantial maternal and perinatal ill-health, particularly in low-income countries where surgery is often less safe. In presence of adequate labour monitoring and by appropriate use of evidence-based interventions for prolonged first stage of labour, unnecessary caesarean sections can be avoided. We aim to describe the incidence of prolonged first stage of labour and the use of amniotomy and augmentation with oxytocin in a low-resource setting in Malawi. METHODS: Retrospective analysis of medical records and partographs of all women who gave birth in 2015 and 2016 in a rural mission hospital in Malawi. Primary outcomes were incidence of prolonged first stage of labour based on partograph tracings, caesarean section indications and utilization of amniotomy and oxytocin augmentation. RESULTS: Out of 3246 women who gave birth in the study period, 178 (5.2%) crossed the action line in the first stage of labour, of whom 21 (11.8%) received oxytocin to augment labour. In total, 645 women gave birth by caesarean section, of whom 241 (37.4%) with an indication 'prolonged first stage of labour'. Only 113 (46.9%) of them crossed the action line and in 71/241 (29.5%) membranes were still intact at the start of caesarean section. Excluding the 60 women with prior caesarean sections, 14/181 (7.7%) received oxytocin prior to caesarean section for augmentation of labour. CONCLUSION: The diagnosis prolonged first stage of labour was often made without being evident from labour tracings and two basic obstetric interventions to prevent caesarean section, amniotomy and labour augmentation with oxytocin, were underused.

Health workers' perspectives on informed consent for caesarean section in Southern Malawi.

OBJECTIVE: Informed consent is a prerequisite for caesarean section, the commonest surgical procedure in low- and middle-income settings, but not always acquired to an appropriate extent. Exploring perceptions of health care workers may aid in improving clinical practice around informed consent. We aim to explore health workers' beliefs and experiences related to principles and practice of informed consent. METHODS: Qualitative study conducted between January and June 2018 in a rural 150-bed mission hospital in Southern Malawi. Clinical observations, semi-structured interviews and a focus group discussion were used to collect data. Participants were 22 clincal officers, nurse-midwives and midwifery students involved in maternity care. Data were analysed to identify themes and construct an analytical framework. RESULTS: Definition and purpose of informed consent revolved around providing information, respecting women's autonomy and achieving legal protection. Due to fear of blame and litigation, health workers preferred written consent. Written consent requires active participation by the consenting individual and was perceived to transfer liability to that person. A woman's refusal to provide written informed consent may pose a dilemma for the health worker between doing good and respecting autonomy. To prevent such refusal, health workers said to only partially disclose surgical risks in order to minimize women's anxiety. Commonly perceived barriers to obtain a fully informed consent were labour pains, language barriers, women's lack of education and their dependency on others to make decisions. CONCLUSIONS: Health workers are familiar with the principles around informed consent and aware of its advantages, but fear of blame and litigation, partial disclosure of risks and barriers to communication hamper the process of obtaining informed consent. Findings can be used to develop interventions to improve the informed consent process.

Impact of Medical Doctors Global Health and Tropical Medicine on decision-making in caesarean section: a pre- and post-implementation study in a rural hospital in Malawi.

BACKGROUND: Medical doctors with postgraduate training in Global Health and Tropical Medicine (MDGHTM) from the Netherlands, a high-income country with a relatively low caesarean section rate, assist associate clinicians in low-income countries regarding decision-making during labour. Objective of this study was to assess impact of the presence of MDGHTMs in a rural Malawian hospital on caesarean section rate and indications. METHODS: This retrospective pre- and post-implementation study was conducted in a rural hospital in Malawi, where MDGHTMs were employed from April 2015. Indications for caesarean section were audited against national protocols and defined as supported or unsupported by these protocols. Caesarean section rates and numbers of unsupported indications for the years 2015 and 2016 per quarter for different staff cadres were assessed by linear regression. RESULTS: Six hundred forty-five women gave birth by caesarean section in the study period. The caesarean rate dropped from 20.1 to 12.8% (p < 0.05, R2 = 0.53, y = - 0.0086x + 0.2295). Overall 132 of 501 (26.3%) auditable indications were not supported by documentation in medical records. The proportion of unsupported indications dropped significantly over time from 47.0 to 4.4% (p < 0.01, R2 = 0.71, y = - 0.0481x + 0.4759). Stratified analysis for associate clinicians only (excluding caesarean sections performed by medical doctors) showed a similar decrease from 48.3 to 6.5% (p < 0.05, R2 = 0.55, y = - 0.0442x + 0.4805). CONCLUSIONS: Our results indicate that presence of MDGHTMs was accompanied by considerable decreases in caesarean section rate and proportion of unsupported indications for caesarean section in this facility. Their presence is likely to have influenced decision-making by associate clinicians.

Higher Recurrence Rate After Endoscopic Totally Extraperitoneal (TEP) Inguinal Hernia Repair With Ultrapro Lightweight Mesh: 5-Year Results of a Randomized Controlled Trial (TULP-trial).

OBJECTIVE: The aim of this study was to determine inguinal hernia recurrence rates 5 years after endoscopic totally extraperitoneal (TEP) inguinal hernia repair when either lightweight or heavyweight mesh was used. BACKGROUND: Recurrence is an important complication of inguinal hernia surgery. Higher recurrence rates of Ultrapro lightweight meshes after TEP repair have been demonstrated, yet data regarding long-term follow-up are limited. METHODS: From 2010 to 2012, 950 male adult patients with primary unilateral hernias were randomized to TEP hernia repair with heavyweight (Prolene) or lightweight (Ultrapro) mesh. Five years postoperatively, the validated PINQ-PHONE telephone questionnaire was carried out. Participants with a positive questionnaire reply were scheduled for a clinical visit. A recurrence was defined as a clinically detectable bulge in the operated groin on physical examination. RESULTS: Data on development of recurrence could be obtained from 790 patients (83.2% 5-year follow-up rate). Four patients presented with a recurrence at the outpatient clinic between 2 and 5 years postoperatively. Thirty-five patients (4.6%) with a positive PINQ-PHONE reply (60.0% lightweight vs 40.0% heavyweight) were physically examined at the outpatient clinic. In 2 patients (lightweight) a recurrence was detected. The total 5-year recurrence rate after TEP hernia repair was 2.4% (3.8% lightweight, 1.1% heavyweight, P = 0.01). A significantly higher recurrence rate for lightweight mesh in primary direct hernias was found (P = 0.003). CONCLUSIONS: The overall recurrence rate 5 years after TEP repair was low. Ultrapro lightweight meshes showed higher recurrence rates than heavyweight meshes and are not recommended for endoscopic TEP inguinal hernia repair.

Optimization of N'-(arylsulfonyl)pyrazoline-1-carboxamidines by exploiting a novel interaction site in the 5-HT6 antagonistic binding pocket.

The discovery of non-basic N'-(arylsulfonyl)pyrazoline-1-carboxamidines as 5-HT6 antagonists with unique structural features was recently disclosed. Here we describe how this structural class was further developed by addressing an unexplored interaction site of the 5-HT6 receptor. Compound 13 resulting from this effort is a highly potent and selective 5-HT6 antagonist with improved metabolic stability. It is furthermore devoid of hERG affinity. Despite its modest CNS/plasma ratio, a high brain free fraction ensured substantial exposure to allow for rodent cognition studies.

Absorption and intracellular accumulation of food-borne dicarbonyl precursors of advanced glycation end-product in a Caco-2 human cell transwell model.

This study aimed to better understand whether and how the reactive 1,2-dicarbonyl precursors of advanced glycation end products (AGEs), glyoxal (GO) and methylglyoxal (MGO), cross the intestinal barrier by studying their transport in the in vitro Caco-2 transwell system. The results reveal that GO, MGO and Nε-(carboxymethyl)lysine (CML), the latter studied for comparison, are transported across the intestinal cell layer via both active and passive transport and accumulate in the cells, albeit all to a limited extent. Besides, the transport of the dicarbonyl compounds was only partially affected by the presence of amino acids and protein, suggesting that scavenging by a food matrix will not fully prevent their intestinal absorption. Our study provides new insights into the absorption of the two major food-borne dicarbonyl AGE precursors and provides evidence of their potential systemic bioavailability but also of factors limiting their contribution to the overall exposome.

Proteomics-based identification of biomarkers reflecting endogenous and exogenous exposure to the advanced glycation end product precursor methylglyoxal in SH-SY5Y human neuroblastoma cells.

Methylglyoxal (MGO), a highly reactive precursor of advanced glycation end products, is endogenously produced and prevalent in various food products. This study aimed to characterize protein modifications in SH-SY5Y human neuroblastoma cells induced by MGO and identify potential biomarkers for its exposure and toxicity. A shot-gun proteomic analysis was applied to characterize protein modifications in cells incubated with and without exogenous MGO. Seventy-seven proteins were identified as highly susceptible to MGO modification, among which eight, including vimentin and histone H2B type 2-F, showing concentration-dependent modifications by externally added MGO, were defined as biomarkers for exogenous MGO exposure. Remarkably, up to 10 modification sites were identified on vimentin. Myosin light polypeptide 6 emerged as a biomarker for MGO toxicity, with modifications exclusively observed under cytotoxic MGO levels. Additionally, proteins like serine/threonine-protein kinase SIK2 and calcyphosin, exhibiting comparable or even higher modification levels in control compared to exogenous MGO-treated cells, were defined as biomarkers for endogenous exposure. Bioinformatics analysis revealed that motor proteins, cytoskeleton components, and glycolysis proteins were overrepresented among those highly susceptible to MGO modification. These results identify biomarkers for both endogenous and exogenous MGO exposure and provide insights into the cellular effects of endogenously formed versus externally added MGO.

Discrimination of Lipogenic or Glucogenic Diet Effects in Early-Lactation Dairy Cows Using Plasma Metabolite Abundances and Ratios in Combination with Machine Learning.

During early lactation, dairy cows have a negative energy balance since their energy demands exceed their energy intake: in this study, we aimed to investigate the association between diet and plasma metabolomics profiles and how these relate to energy unbalance of course in the early-lactation stage. Holstein-Friesian cows were randomly assigned to a glucogenic (n = 15) or lipogenic (n = 15) diet in early lactation. Blood was collected in week 2 and week 4 after calving. Plasma metabolite profiles were detected using liquid chromatography-mass spectrometry (LC-MS), and a total of 39 metabolites were identified. Two plasma metabolomic profiles were available every week for each cow. Metabolite abundance and metabolite ratios were used for the analysis using the XGboost algorithm to discriminate between diet treatment and lactation week. Using metabolite ratios resulted in better discrimination performance compared with the metabolite abundances in assigning cows to a lipogenic diet or a glucogenic diet. The quality of the discrimination of performance of lipogenic diet and glucogenic diet effects improved from 0.606 to 0.753 and from 0.696 to 0.842 in week 2 and week 4 (as measured by area under the curve, AUC), when the metabolite abundance ratios were used instead of abundances. The top discriminating ratios for diet were the ratio of arginine to tyrosine and the ratio of aspartic acid to valine in week 2 and week 4, respectively. For cows fed the lipogenic diet, choline and the ratio of creatinine to tryptophan were top features to discriminate cows in week 2 vs. week 4. For cows fed the glucogenic diet, methionine and the ratio of 4-hydroxyproline to choline were top features to discriminate dietary effects in week 2 or week 4. This study shows the added value of using metabolite abundance ratios to discriminate between lipogenic and glucogenic diet and lactation weeks in early-lactation cows when using metabolomics data. The application of this research will help to accurately regulate the nutrition of lactating dairy cows and promote sustainable agricultural development.

Deoxynivalenol increases pro-inflammatory cytokine secretion and reduces primary bile acid transport in an inflamed intestinal in vitro co-culture model.

The fungal secondary metabolite deoxynivalenol (DON) that can contaminate cereal-based food products not only induces inflammation but also reduces bile acid absorption by a healthy human intestine. Bile acid malabsorption is commonly observed in individuals with an inflamed intestine. Here we studied the effects of DON on inflammation and primary bile acid transport using an in vitro model for an inflamed intestine. An inflamed intestinal in vitro model was established by co-culturing a Caco-2 cell-layer and LPS-pre-stimulated THP-1 macrophages in Transwells. We observed a decreased transport of 5 primary bile acids across inflamed co-cultures compared to healthy co-cultures but not of chenodeoxycholic acid. DON exposure further reduced the transport of the affected primary bile acids across the inflamed co-cultures. DON exposure also enhanced the secretion of pro-inflammatory cytokines in the inflamed co-cultures, while it did not increase the pro-inflammatory cytokines secretion from LPS-pre-stimulated THP-1 monocultures. Exposure of Caco-2 cell-layers to pro-inflammatory cytokines or THP-1 conditioned media partly mimicked the DON-induced effects of the co-culture model. Local activation of intestinal immune cells reinforces the direct pro-inflammatory effects of DON on intestinal epithelial cells. This affects the bile acid intestinal kinetics in an inflamed intestine.

Ribotoxin deoxynivalenol induces taurocholic acid malabsorption in an in vitro human intestinal model.

The trichothecene toxin deoxynivalenol (DON) is a ribotoxic mycotoxin that contaminates cereal-based food. DON binds to ribosomes, thereby inhibiting protein translation and activating stress mitogen-activated protein kinases (MAPK). The activation of MAPK induces pro-inflammatory cytokine production. Emerging evidence showed that DON decreased bile acid reabsorption and apical sodium-dependent bile acid transporter (ASBT) expression in Caco-2 cell layers. We hypothesized that the effect of DON on decreased ASBT mRNA expression is regulated via pro-inflammatory cytokines. We observed that MAPK inhibitors prevented DON to induce IL-8 secretion and prevented the DON-induced downregulation of ASBT mRNA expression. However, DON-induced taurocholic acid (TCA) transport reduction was not prevent by the MAPK inhibitors. We next observed a similarity between the activity of the non-inflammatory ribotoxin cycloheximide and DON to decrease TCA transport, which is consistent with their common ability to inhibit protein synthesis. Together, our results suggest that DON-induced TCA malabsorption is regulated by MAPK activation-induced pro-inflammatory cytokine production and protein synthesis inhibition, both of which are initiated by DON binding to the ribosomes which therefore is the molecular initiating event for the adverse outcome of bile acid malabsorption. This study provides insights into the mechanism of ribotoxins-induced bile acid malabsorption in human intestine.

On the Role of ROS and Glutathione in the Mode of Action Underlying Nrf2 Activation by the Hydroxyanthraquinone Purpurin.

Purpurin is a major anthraquinone present in the roots of Rubia cordifolia (madder). Purpurin is known to activate Nrf2 (Nuclear transcription factor erythroid 2-related factor 2) EpRE (electrophile responsive element) mediated gene expression as a potential beneficial effect. This study aimed to elucidate the balance between the electrophilicity or pro-oxidant activity of purpurin underlying the Nrf2 induction. For this, Nrf2 activation with modified intracellular glutathione (GSH) levels was measured in an Nrf2 CALUX reporter gene assay. In addition, both cell-free and intracellular ROS formation of purpurin with modified (intracellular) GSH levels at different pH were quantified using the DCF-DA assay. GSH adduct formation was evaluated by UPLC and LC-TOF-MS analysis. GSH and GSSG levels following purpurin incubations were quantified by LC-MS/MS. We show that Nrf2 induction by purpurin was significantly increased in cells with buthionine sulfoximine depleted GSH levels, while Nrf2 induction was decreased upon incubation of the cells with N-acetylcysteine being a precursor of GSH. In cell-free incubations, ROS formation increased with increasing pH pointing at a role for the deprotonated form of purpurin. Upon incubations of purpurin with GSH at physiological pH, GSH adduct formation appeared negligible (<1.5% of the added purpurin). The addition of GSH resulted in conversion of GSH to GSSG and significantly reduced the ROS formation. Together these results demonstrate that Nrf2 induction by purpurin originates from intracellular ROS formation and not from its electrophilicity, which becomes especially relevant when intracellular GSH levels can no longer scavenge the ROS. The present study demonstrated that the efficiency of intracellular Nrf2 activation by purpurin and related anthraquinones will depend on (i) their pKa and level of deprotonation at the intracellular pH, (ii) the oxidation potential of their deprotonated form and (iii) the intracellular GSH levels. Thus, the Nrf2 induction by purpurin depends on its pro-oxidant activity and not on its electrophilicity.

Induction of Nrf2-EpRE-mediated gene expression by hydroxyanthraquinones present in extracts from traditional Chinese medicine and herbs.

Hydroxyanthraquinones that can be present in traditional Chinese medicine (TCM) and herbal extracts have claimed beneficial intestinal effects. We examined the ability of a panel hydroxyanthraquinones, and methanolic extracts from selected TCM and herbal granules to activate Nrf2-EpRE mediated gene expression using a reporter-gene assay. The results indicate that purpurin, aloe-emodin, 2-hydroxy-3-methylanthraquinone and rhein induced Nrf2 mediated gene expressions with a high induction factor (IFs>10), with BMCL10 values (the lower confidence limit of the concentration giving 10% added response above background) of 16 µM, 1.1 µM, 23 µM and 2.3 µM, respectively, while aurantio-obtusin, obtusifolin, rubiadin 1-methyl ether and emodin were less potent (IFs<5), with BMCL10 values for added response above background level of 4.6 µM, 15 µM, 9.8 µM and 3.8 µM, respectively. All TCM extracts and the herbal extracts of Aloe Vera, Polygonum multiflorum, Rubia (cordifolia) and Rheum officinale activated the Nrf2-EpRE pathway. Of the TCM extracts, Chuan-Xin-Lian-Kang-Yan-Pian was the most potent Nrf2-inducer. LC-MS/MS analysis indicated the presence of selected hydroxyanthraquinones in the extracts and herbs, in part explaining their Nrf2-EpRE mediated activity. In conclusion, different hydroxyanthraquinones have different potencies of Nrf2 activation. The Nrf2 activation by extracts from TCM and herbs can be partially explained by the presence of selected hydroxyanthraquinones.

In vitro models to measure effects on intestinal deconjugation and transport of mixtures of bile acids.

Bile acid metabolism and transport are critical to maintain bile acid homeostasis and host health. In this study, it was investigated if effects on intestinal bile acid deconjugation and transport can be quantified in vitro model systems using mixtures of bile acids instead of studying individual bile acids. To this end deconjugation of mixtures of selected bile acids in anaerobic rat or human fecal incubations and the effect of the antibiotic tobramycin on these reactions was studied. In addition, the effect of tobramycin on the transport of the bile acids in isolation or in a mixture across Caco-2 cell layers was characterized. The results demonstrate that both the reduction of bile acid deconjugation and transport by tobramycin can be adequately detected in vitro systems using a mixture of bile acids, thus eliminating the need to characterize the effects for each bile acid in separate experiments. Subtle differences between the experiments with single or combined bile acids point at mutual competitive interactions and indicate that the use of bile acid mixtures is preferred over use of single bile acid given that also in vivo bile acids occurs in mixtures.

Comparison of the methylglyoxal scavenging effects of kaempferol and glutathione and the consequences for the toxicity of methylglyoxal in SH-SY5Y cells.

This study aimed to characterize the methylglyoxal (MGO) scavenging capacity of glutathione (GSH) and kaempferol in more detail with special emphasis on the possible reversible nature of the adduct formation and their competition for MGO, and the safety consequences of their MGO-scavenging effects. GSH showed immediate and concentration-dependent MGO-scavenging effects, while the scavenging effects by kaempferol appeared concentration- but also time-dependent, with stable adducts formed over time. The GSH adduct gradually disappeared in a competition reaction with kaempferol, and kaempferol became the preferred scavenger over time. Furthermore, the scavenging of MGO by kaempferol provided better protection than GSH against extracellular MGO in SH-SY5Y cells. It is concluded that flavonoids like kaempferol provide better scavengers for food-borne MGO than thiol-based scavengers such as GSH, while, given the endogenous concentrations of both scavengers and the detoxification of the GSH-MGO adduct by the glyoxalase system, GSH will be dominant for intracellular MGO protection.