Atazanavir-induced unconjugated hyperbilirubinemia prevents vascular hyporeactivity during experimental human endotoxemia

Objective

Inflammation-induced free radical release is important in the pathogenesis of several diseases, including atherosclerosis and sepsis. Heme oxygenase (HO) breaks down heme into carbon monoxide, iron, and biliverdin. Biliverdin IXα is directly converted to bilirubin by biliverdin reductase. Unconjugated bilirubin is a powerful antioxidant, and elevated levels have beneficial effects in preclinical models and human cardiovascular disease. However, its impact during acute inflammation in humans is unknown. In the present study, we investigated the impact of atazanavir-induced (unconjugated) hyperbilirubinemia on antioxidant capacity, inflammation, and vascular dysfunction in human experimental endotoxemia.

Approach and results

Following double-blinded four-day treatment with atazanavir 2dd300 mg (or placebo), twenty healthy male volunteers received 2 ng/kg Escherichia coli lipopolysaccharide intravenously. Blood was drawn to determine the bilirubin levels, antioxidant capacity, and cytokine response. It was demonstrated that following atazanavir treatment, total bilirubin concentrations increased to maximum values of 4.67 (95%CI 3.91-5.59) compared to 0.82 (95%CI 0.64-1.07) mg/dL in the control group (p<0.01). Furthermore, the anti-oxidant capacity, as measured by the ferric-reducing ability of plasma (FRAP), was significantly increased with 36% in hyperbilirubinemia subjects (p<0.0001), and FRAP concentrations correlated strongly to bilirubin concentrations (R2 = 0.77, p<0.001). Hyperbilirubinemia attenuated the release of interleukin-10 from 377 (95%CI 233-609) to 219 (95%CI 152-318) pg/mL (p=0.01), whereas the release of pro-inflammatory cytokines remained unaltered. In vitro, in the absence of hyperbilirubinemia, atazanavir did not influence lipopolysaccharide-induced cytokine release in a whole blood assay. Vascular function was assessed using forearm venous occlusion plethysmography after intra-arterial infusion of acetylcholine and nitroglycerin. Hyperbilirubinemia completely prevented the LPS-associated blunted vascular response to acetylcholine and nitroglycerin.

Conclusions

Atazanavir-induced hyperbilirubinemia increases antioxidant capacity, attenuates interleukin-10 release, and prevents vascular hyporesponsiveness during human systemic inflammation elicited by experimental endotoxemia.

Clinical trial registration

http://clinicaltrials.gov, identifier NCT00916448.

Nitrogen-Phosphorus-Potassium containing liquid fertilizer intoxication presenting with extreme hyperkalemia, metabolic acidosis and ECG changes

Liquid fertilizers are widely used for fertilizing in- and outdoor vegetation. Despite the easy accessibility and widespread use, serious intoxications are rare. This case report describes a 61-year-old woman who was treated for life-threatening hyperkalemia, metabolic acidosis and ECG changes after intentional ingestion of liquid fertilizer. Our case shows that intake of liquid fertilizer, though infrequent, can cause serious, life threatening complications.

[Suicide attempts with castor beans and jequirity beans]

BACKGROUND

Intoxications by beans can have serious consequences. We describe 2 auto-intoxications using castor beans and jequirity beans with the toxins ricin and abrin, respectively. Both toxins have similar mechanisms of action. When taken orally, a toxic mucositis develops causing dehydration, gastrointestinal blood loss and multi-organ failure. Knowledge about pathophysiology is important for risk assessment and treatment.

CASE DESCRIPTION

Patient A presented 27 hours after ingestion of the castor beans with frequent vomiting and watery diarrhea. Patient B presented 45 minutes after ingestion of jequirity beans without physical complaints. Gastric lavage and bowel lavage was started. The clinical course in both patients was mild. The severity of toxicity depends on how much the beans have been chewed and the amount of ricin/abrin per bean.

CONCLUSION

Intoxications with ricin or abrin can be potentially serious. There is no antidote. Treatment consists of anti-absorptive measures and best supportive care.

Significant toxicity following an increase in poisonings with designer benzodiazepines in the Netherlands between 2010 and 2020

BACKGROUND

Designer benzodiazepines (DBs) are an emerging class of new psychoactive substances. While structurally derived from pharmaceutical benzodiazepines, their toxicological profile is less clear. We investigated time trends in the rate of DB poisonings and their clinical toxicity.

METHODS

A retrospective observational study was performed on the incidence rate of DB poisonings, relative to all recreational drug poisonings reported to the Dutch Poisons Information Center (DPIC) from 2010 to 2020. Time-trend analysis was performed using Poisson regression. A prospective cohort study was performed on toxicity of DBs, including the Poisoning Severity Score, from January 2016-June 2019. Data was collected through telephone interviews.

RESULTS

Between 2010 and 2020, the DPIC was consulted on 142 DB exposures. The incidence rate of DB exposures increased from 0.1% to 4.3%, with a year effect estimate of 1.35 (95% CI [1.14;1.54]). Twenty different DBs were reported, mostly etizolam (33%), clonazolam (17%), and flunitrazolam (8%). During consultation (often shortly after exposure), poisoning was graded moderate-severe in 29% of cases (n = 146). In the prospective cohort sample with follow-up (n = 22), 86% of cases (n = 19) showed a moderate-severe poisoning. The severity of poisoning did not differ between mono- and mixed intoxications. Frequently reported symptoms in the prospective cohort sample included drowsiness (86%), confusion (59%), and agitation (55%). Coma was observed in seven cases (32%) and respiratory depression requiring mechanical ventilation in five cases (23%).

CONCLUSION

The rate of DB poisonings reported to the DPIC strongly increased from 2010 to 2020, indicating increased (ab)use of DBs. Most DB exposures resulted in moderate-severe toxicity with neurological effects.

[Psychotropic drugs and QTc prolongation]

Assessment of the risk for arrhythmias requires knowledge of QTc interval prolonging drugs and baseline clinical risk factors for QTc prolongation. The combination of both determines whether ECG-monitoring is necessary at the start of a psychotropic drug. In this article, we summarize current literature regarding appropriate methods of calculating the QTc interval, risk factors for QTc prolongation and QTc-prolonging psychotropic drugs. The frequency of cardiac monitoring for patients receiving psychotropic drugs should be individually determined, based on the prescribed agent(s) and additional risk factors for TdP. In patients without baseline clinical risk factors for QTc prolongation or cardiac arrhythmias, starting a single psychotropic drug with a low risk profile, ECG-monitoring might not be necessary.

Study of enteric pathogens among children in the tropics and effects of prolonged storage of stool samples

The study was performed to compare real-time PCR after nucleic acid extraction directly from stool samples as well as from samples stored and transported on Whatman papers or flocked swabs at ambient temperature in the tropics. In addition, the possible suitability for a clear determination of likely aetiological relevance of PCR-based pathogen detections based on cycle threshold (Ct) values was assessed. From 632 Tanzanian children <5 years of age with and without gastrointestinal symptoms, 466 samples were subjected to nucleic acid extraction and real-time PCR for gastrointestinal viral, bacterial and protozoan pathogens. Equal or even higher frequencies of pathogen detections from Whatman papers or flocked swabs were achieved compared with nucleic acid extraction directly from stool samples. Comparison of the Ct values showed no significant difference according to the nucleic acid extraction strategy. Also, the Ct values did not allow a decision whether a detected pathogen was associated with gastrointestinal symptoms.

[Drug of abuse screening in urine in emergency situations; useful or not?]

Drug of abuse (DOA) screening in urine is often performed in the clinical emergency setting. However, there is considerable evidence that questions the usefulness of this screening in the acute management of patients with suspected intoxications. The used method is an immunoassay, in which cross reactivity with false positive results may occur. A positive result does not always indicate current toxicity, a negative result does not exclude drug use or a current intoxication. Therefore, DOA screening has limited value in the acute clinical management of patients with intoxications.

Toxicological analysis of azide and cyanide for azide intoxications using gas chromatography

Azide is a highly toxic chemical agent to human being. Accidental, but also intentional exposure to azide occurs. To be able to confirm azide ingestion, we developed a method to identify and quantify azide in biological matrices. Cyanide was included in the method to evaluate suggested in vivo production of cyanide after azide ingestion. Azide in biological matrices was first derivatized by propionic anhydride to form propionyl azide. Simultaneously, cyanide was converted into hydrogen cyanide. After thermal rearrangement of propionyl azide, ethyl isocyanate was formed, separated together with hydrogen cyanide by gas chromatography (GC) and detected using a nitrogen phosphorous detector (NPD). The method was linear from 1.0‐100 µg/mL for both analytes, and azide was stable in human plasma at −20°C for at least 49 days. Azide was measured in the gastric content of two cases of suspected azide ingestion (case 1:1.2 mg/mL, case 2:1.5 mg/mL). Cyanide was only identified in the gastric content of case 1 (approximately 1.4 µg/mL). Furthermore, azide was quantified in plasma (19 µg/mL), serum (24 µg/mL), cell pellet (21 µg/mL) and urine (3.0 µg/mL) of case 2. This method can be used to confirm azide and cyanide exposure, and azide concentrations can be quantified in several biological matrices.

Dermaseptins, Multifunctional Antimicrobial Peptides: A Review of Their Pharmacology, Effectivity, Mechanism of Action, and Possible Future Directions

Dermaseptins are a group of α-helical shaped polycationic peptides isolated from the Hylid frogs, with antimicrobial effects against bacteria, parasites, protozoa, viruses in vitro. Besides, anti-tumor effects have been demonstrated. However, few animal experiments and no clinical trials have been conducted thus far. This review summarizes the current knowledge on the pharmacology, ethno pharmacology, effectivity against infectious pathogens and tumors cells and the mechanism of action of the Dermaseptins. Future research should focus on further clarification of the mechanisms of action, the effectivity of Dermaseptins against several cancer cell lines and their applicability in humans.

A quarter of admitted poisoned patients have a mild poisoning and require no treatment: An observational study

BACKGROUND

Poisoned patients are frequently admitted following Emergency Department (ED) presentation, while the necessity of such admissions is hardly investigated. We determined the proportion and characteristics of poisoned patients who were admitted, but in retrospect had an uneventful admission.

METHODS

For this observational cohort study, all patients presented to the ED of a Dutch University Hospital with various poisonings during a 1.5-year period (January 2015-July 2016) were included. The uneventfulness of admissions, defined as patients with a low Poisoning Severity Score (PSS) who received no treatment, was determined in retrospect.

RESULTS

We included 417 patients who visited the ED for poisoning. 247 Patients were admitted: 30% to a general ward, 58% to a MCU, and 12% to the ICU. The poisoning severity scores of the admitted patients were none to mild in 38%, moderate to severe in 59%, and fatal in 2%. Upon admission, 60% of the patients received treatment. In retrospect, 77% of the admitted patients had a moderate, severe or fatal poisoning and/or required treatment. However, 23% of the admitted patients had a mild poisoning and required no treatment. This group involved younger patients (median age of 23 versus 42 years) and a higher proportion of patients reporting exposure to only one substance (65% versus 51%).

CONCLUSIONS

The majority of poisoned patients presented to the ED was admitted, while in retrospect, a quarter of these admissions were uneventful. Predictive parameters should be sought to identify patients who can be sent home safely.

Parenteral bilirubin in healthy volunteers: a reintroduction in translational research

AIMS

Preclinical results suggest therapeutic potential of mild hyperbilirubinemia in T2DM and cardiovascular disease. Translational data are limited, because an appropriate bilirubin formulation for parenteral human use is lacking. Considering its use in both clinical practice and medical research in the past, we explored the feasibility to reintroduce parenteral bilirubin for translational experiments.

METHODS

We developed a preparation method in accordance with good manufacturing practice and evaluated the parenteral applicability in healthy volunteers (n = 8). Explorative pharmacokinetic and safety data were compared to the results from a literature study on the former parenteral use of bilirubin. Bilirubin was administered intra-arterially to raise the local plasma concentration in the forearm vascular bed (n = 4) and intravenously to raise the systemic plasma concentration (n = 4). Finally, pharmacokinetic characteristics were studied following a single bolus infusion (n = 3).

RESULTS

During parenteral application, no side effects occurred. Adverse events mentioned during the two-week observation period were in general mild and self-limiting. Three more significant adverse events (appendicitis, asymptomatic cardiac arrhythmia and atopic eczema) were judged unrelated by independent physicians. A dose-concentration relationship appeared sufficiently predictable for both intra-arterial and intravenous administration. In line with existing knowledge, bilirubin pharmacokinetics could be described best according to a two-compartment model with a volume of distribution of 9.9 (±2.0) l and a total plasma clearance of 36 (±16) ml per minute.

CONCLUSIONS

Supported by previous reports, our data suggest that it is both feasible and safe to perform translational experiments with parenteral albumin bound bilirubin.

[Intoxication with new psychoactive substances: drug unknown, but complications are still treatable]

Abuse of new psychoactive substances (NPS) and the number of patients presenting to the ER with intoxication are increasing. Treatment may at first sight seem complicated because of limited knowledge of the substance involved, but should be based on a general supportive approach recognising the relatively predictable spectrum of symptoms caused by adrenergic, serotonergic and dopaminergic stimulation. In this article, we discuss the vital elements of this approach and possible complications of NPS intoxication. This is illustrated by two 20-year-old male patients with NPS intoxication who presented to our ER as participants in a group intoxication. Patient A suffered from mild symptoms and tested positive for 4-iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (2C-I-NBOMe) only. Patient B presented with agitated delirium and tested positive for both 2C-I-NBOMe and cocaine. While patient A was treated with benzodiazepines and rehydration, patient B required sedation, intubation and short-term ventilation.

[Aggression and restlessness following baclofen overdose: the narrow line between intoxication and withdrawal symptoms]

BACKGROUND

Baclofen is increasingly prescribed for alcohol dependency. Subsequently, the risk of self-intoxication with this medicinal product is increasing.

CASE DESCRIPTION

A 23-year-old man with a history of alcohol dependence was admitted to our hospital after self-intoxication with 2700 mg baclofen and 330 mg mirtazapine. Respiratory insufficiency as a result of the baclofen intoxication required intubation and admission to the ICU. During the first day, despite the use of sedatives, the patient became intermittently agitated and aggressive. In the following days, he developed severe delirium, probably due to baclofen withdrawal. The reintroduction of baclofen quickly resolved these symptoms.

CONCLUSION

In the case of baclofen, in practice it is difficult to differentiate between intoxication and withdrawal. To prevent potentially severe withdrawal symptoms, we recommend reintroduction of baclofen when the first signs of restlessness and agitation arise following intoxication.

Vascular and metabolic effects of the haem oxygenase-1 inducer haem arginate in subjects with the metabolic syndrome: A translational cross-over study

This translational randomized and vehicle-controlled cross-over study was performed to assess the impact of haem arginate treatment on haem oxygenase-1 induction, endothelial function and insulin sensitivity in subjects with the metabolic syndrome (n = 14). Both treatment periods consisted of 5 days. Haem arginate or vehicle (l-arginine) was administered intravenously on Days 1 and 3. Forearm blood flow in response to acetylcholine and nitroglycerine was measured by venous occlusion plethysmography (Day 3), insulin sensitivity by a hyperinsulinaemic clamp procedure (Day 5). Haem arginate did not improve endothelial function or insulin sensitivity but significantly reduced the vasodilator response to nitroglycerine (p < 0.01). These negative findings are in contrast to the preclinical data, which may be due to short duration of therapy and limited haem oxygenase-1 induction as well as interference by markedly elevated plasma haem levels observed after haem arginate treatment (p < 0.01). Future studies should pay attention to the delicate balance between sufficient dosing and timely normalization of plasma haem levels.

Group B Streptococci serotype distribution in pregnant women in Ghana: assessment of potential coverage through future vaccines

OBJECTIVE

Group B streptococcal (GBS) colonization of pregnant women can lead to subsequent infection of the new-born and potentially fatal invasive disease. Data on GBS colonization prevalence and serotype distribution from Africa are scarce, although GBS-related infections are estimated to contribute substantially to infant mortality. In recent years, GBS vaccine candidates provided promising results in phase I and II clinical trials. We aimed to assess the prevalence and serotype distribution of GBS in Ghana since this knowledge is a prerequisite for future evaluation of vaccine trials.

METHODS

This double-centre study was conducted in one rural and one urban hospital in central Ghana, West Africa. Women in late pregnancy (≥35 weeks of gestation) attending the antenatal care clinic (ANC) provided recto-vaginal swabs for GBS testing. GBS isolates were analysed for serotype and antibiotic susceptibility. GBS-positive women were treated with intrapartum antibiotic prophylaxis (IAP) according to current guidelines of the Center for Disease Control and Prevention (CDC).

RESULTS

In total, 519 women were recruited at both study sites, recto-vaginal swabs were taken from 509. The overall prevalence of GBS was 19.1% (18.1% in rural Pramso and 23.1% in urban Kumasi, restrospectively). Capsular polysaccharide serotype (CPS) Ia accounted for the most frequent serotype beyond all isolates (28.1%), followed by serotype V (27.1%) and III (21.9%). No resistance to Penicillin was found, resistances to second line antibiotics clindamycin and erythromycin were 3.1% and 1%, respectively.

DISCUSSION

Group B Streptococcus serotype distribution in Ghana is similar to that worldwide, but variations in prevalence of certain serotypes between the urban and rural study site were high. Antibiotic resistance of GBS strains was surprisingly low in this study.

Cell-type-specific downregulation of heme oxygenase-1 by lipopolysaccharide via Bach1 in primary human mononuclear cells

Heme oxygenase (HO)-1 is the inducible isoform of the heme-degrading enzyme HO, which is upregulated by multiple stress stimuli. HO-1 has major immunomodulatory and anti-inflammatory effects via its cell-type-specific functions in mononuclear cells. Contradictory findings have been reported on HO-1 regulation by the Toll-like receptor (TLR) 4 ligand lipopolysaccharide (LPS) in these cells. Therefore, we reinvestigated the effects of LPS on HO-1 gene expression in human and murine mononuclear cells in vitro and in vivo. Remarkably, LPS downregulated HO-1 in primary human peripheral blood mononuclear cells (PBMCs), CD14(+) monocytes, macrophages, dendritic cells, and granulocytes, but upregulated this enzyme in primary murine macrophages and human monocytic leukemia cell lines. Furthermore, experiments with human CD14(+) monocytes revealed that activation of other TLRs including TLR1, -2, -5, -6, -8, and -9 decreased HO-1 mRNA expression. LPS-dependent downregulation of HO-1 was specific, because expression of cyclooxygenase-2, NADP(H)-quinone oxidoreductase-1, and peroxiredoxin-1 was increased under the same experimental conditions. Notably, LPS upregulated expression of Bach1, a critical transcriptional repressor of HO-1. Moreover, knockdown of this nuclear factor enhanced basal and LPS-dependent HO-1 expression in mononuclear cells. Finally, downregulation of HO-1 in response to LPS was confirmed in PBMCs from human individuals subjected to experimental endotoxemia. In conclusion, LPS downregulates HO-1 expression in primary human mononuclear cells via a Bach1-mediated pathway. As LPS-dependent HO-1 regulation is cell-type- and species-specific, experimental findings in cell lines and animal models need careful interpretation.

The Bilirubin-Increasing Drug Atazanavir Improves Endothelial Function in Patients With Type 2 Diabetes Mellitus

Objective—

In type 2 diabetes mellitus (T2DM), oxidative stress gives rise to endothelial dysfunction. Bilirubin, a powerful endogenous antioxidant, significantly attenuates endothelial dysfunction in preclinical experiments. The Gilbert syndrome is accompanied by a mild and lifelong hyperbilirubinemia and associated with only one third of the usual cardiovascular mortality risk. The hyperbilirubinemia caused by atazanavir treatment closely resembles the Gilbert syndrome. We thus hypothesized that treatment with atazanavir would ameliorate oxidative stress and vascular inflammation and improve endothelial function in T2DM.

Methods and Results—

In a double-blind, placebo-controlled crossover design, we induced a moderate hyperbilirubinemia by a 3-day atazanavir treatment in 16 subjects experiencing T2DM. On the fourth day, endothelial function was assessed by venous occlusion plethysmography. Endothelium-dependent and endothelium-independent vasodilation were assessed by intraarterial infusion of acetylcholine and nitroglycerin, respectively. Atazanavir treatment induced an increase in average bilirubin levels from 7 μmol/L (0.4 mg/dL) to 64 μmol/L (3.8 mg/dL). A significant improvement in plasma antioxidant capacity ( P <0.001) and endothelium-dependent vasodilation ( P =0.036) and a decrease in plasma von Willebrand factor ( P =0.052) were observed.

Conclusion—

Experimental hyperbilirubinemia is associated with a significant improvement of endothelial function in T2DM.

Rosuvastatin increases extracellular adenosine formation in humans in vivo: a new perspective on cardiovascular protection

OBJECTIVE

Statins may increase extracellular adenosine formation from adenosine monophosphate by enhancing ecto-5'-nucleotidase activity. This theory was tested in humans using dipyridamole-induced vasodilation as a read-out for local adenosine formation. Dipyridamole inhibits the transport of extracellular adenosine into the cytosol resulting in increased extracellular adenosine and subsequent vasodilation. In addition, we studied the effect of statin therapy in a forearm model of ischemia-reperfusion injury.

METHODS AND RESULTS

Volunteers randomly received rosuvastatin or placebo in a double-blind parallel design (n=21). The forearm vasodilator response to intraarterial dipyridamole was determined in the absence and presence of the adenosine antagonist caffeine. During a separate visit the vasodilator response to nitroprusside and adenosine was established. In addition, healthy men were randomly divided in 3 groups to receive either placebo (n=10), rosuvastatin (n=22), or rosuvastatin combined with intravenous caffeine (n=12). Subsequently, volunteers performed forearm ischemic exercise. At reperfusion, Tc-99m-labeled annexin A5 was infused intravenously and scintigraphic images were acquired, providing an early marker of cell injury. Rosuvastatin treatment significantly increased the vasodilator response to dipyridamole, which was prevented by caffeine. Rosuvastatin did not influence the response to either sodium nitroprusside or adenosine indicating a specific interaction between rosuvastatin and dipyridamole, which does not result from an effect of rosuvastatin on adenosine clearance nor adenosine-receptor affinity or efficacy. Rosuvastatin increased tolerance to ischemia-reperfusion injury, which was attenuated by caffeine.

CONCLUSIONS

Rosuvastatin increases extracellular adenosine formation, which provides protection against ischemia-reperfusion injury in humans in vivo. Therefore, statins and dipyridamole may interact synergistically.

Complex stability of ferrous ascorbate in aqueous solution and its significance for iron absorption

The greater absorption of iron in vivo from ferrous ascorbate [Fe(HL)2] as compared with ferrous sulfate has been ascribed both to retardation or prevention of Fe(II) oxidation by ascorbate and to the existence of Fe(II) as a chelate with ascorbate. The available literature and our own results demonstrate that Fe(HL)2 dissociates in aqueous solution into a monomeric cationic species Fe(HL)1+, Fe2+ and HL-. The HL anion acts as a monodentate. The low stability constant KFe(HL)1, about 20 l.mol-1 at mu = 0 and 25 degrees C, results in the conclusion that Fe(HL)2 is almost completely dissociated into Fe2+ and HL- at about pH = 5, so (chelate) complex formation does not contribute significantly to the increased iron absorption. Between pH = 6 and pH = 8 a solubility enhancing effect of ascorbate is observed which may be of relevance for the iron absorption from ferrous ascorbate.

Stability of corticosteroids under anaerobic conditions. VII. 17a-hydroxy-17a-hydroxymethyl-17-keto-D-homosteroid phosphate

The major decomposition product of prednisolone phosphate formed under anaerobic decomposition conditions in aqueous solution at pH = 8.3 is identified as 17a-hydroxy-17a-hydroxymethyl-17-keto-D-homosteroid phosphate. The chromatographic properties, the isolation and the structure elucidation of both the D-homosteroid phosphate and its specific dephosphorylated analogue are given. Finally a mechanism leading to the D-homosteroid phosphate is postulated.