A year-long extended release nanoformulated cabotegravir prodrug.

Long-acting cabotegravir (CAB) extends antiretroviral drug administration from daily to monthly. However, dosing volumes, injection site reactions and health-care oversight are obstacles towards a broad usage. The creation of poloxamer-coated hydrophobic and lipophilic CAB prodrugs with controlled hydrolysis and tissue penetrance can overcome these obstacles. To such ends, fatty acid ester CAB nanocrystal prodrugs with 14, 18 and 22 added carbon chains were encased in biocompatible surfactants named NMCAB, NM2CAB and NM3CAB and tested for drug release, activation, cytotoxicity, antiretroviral activities, pharmacokinetics and biodistribution. Pharmacokinetics studies, performed in mice and rhesus macaques, with the lead 18-carbon ester chain NM2CAB, showed plasma CAB levels above the protein-adjusted 90% inhibitory concentration for up to a year. NM2CAB, compared with NMCAB and NM3CAB, demonstrated a prolonged drug release, plasma circulation time and tissue drug concentrations after a single 45 mg per kg body weight intramuscular injection. These prodrug modifications could substantially improve CAB's effectiveness.

Cytotoxic and estrogenic activity of chlorpyrifos and its metabolite 3,5,6-trichloro-2-pyridinol. Study of marine yeasts as potential toxicity indicators.

Chlorpyrifos (CP) is one of the organophosphate insecticides most used worldwide today. Although the main target organ for CP is the nervous system triggering predominantly neurotoxic effects, it has suggested other mechanisms of action as cytotoxicity and endocrine disruption. The risk posed by the pesticide metabolites on non-target organisms is increasingly recognized by regulatory agencies and natural resource managers. In the present study, cytotoxicity and estrogenic activity of CP, and its principal metabolite 3,5,6-trichloro-2-pyridinol (TCP) have been evaluated by in vitro assays, using two mammalian cell lines (HEK293 and N2a), and a recombinant yeast. Results indicate that TCP is more toxic than CP for the two cell lines assayed, being N2a cells more sensitive to both compounds. Both compounds show a similar estrogenic activity being between 2500 and 3000 times less estrogenic than 17ß-estradiol. In order to find new toxicity measurement models, yeasts isolated from marine sediments containing CP residues have been tested against CP and TCP by cell viability assay. Of the 12 yeast strains tested, 6 of them showed certain sensitivity, and a concentration-dependent response to the tested compounds, so they could be considered as future models for toxicity tests, although further investigations and proves are necessary.

Lifetime antiretroviral exposure and neurocognitive impairment in HIV.

Despite the availability of modern antiretroviral therapy (ART), neurocognitive impairment persists among some persons with HIV (PWH). We investigated the role of exposure to four major classes of ARTs in neurocognitive impairment in PWH. A single-site cohort of 343 PWH was recruited. Lifetime ART medication history was obtained from medical health records. We evaluated the role of ART exposure as a predictor of neurocognitive impairment using univariate analyses and machine learning, while accounting for potential effects of demographic, clinical, and comorbidity-related risk factors. Out of a total of 26 tested variables, two random forest analyses identified the most important characteristics of a neurocognitively impaired group (N = 59): Compared with a neurocognitively high-performing group (N = 132; F1-score = 0.79), we uncovered 13 important risk factors; compared with an intermediate-performing group (N = 152; F1-score = 0.75), 16 risk factors emerged. Longer lifetime ART exposure, especially to integrase inhibitors, was one of the most important predictors of neurocognitive impairment in both analyses (rank 2 of 13 and rank 4 of 16, respectively), superseding effects of age (rank 11/13, rank 15/16) and HIV duration (rank 13/13, rank 16/16). Concerning specific integrase inhibitors, the impaired group had significantly longer dolutegravir exposure (p = 0.011) compared with the high-performing group (p = 0.012; trend compared with the intermediate group p = 0.063). A longer duration to integrase inhibitor intake was negatively related to cognition in this cohort. Our findings suggest that possible cognitive complications of long-term exposure to integrase inhibitors, in particular dolutegravir, should be closely monitored in PWH.

Nox1/4 inhibition exacerbates age dependent perivascular inflammation and fibrosis in a model of spontaneous hypertension.

Hypertension is associated with oxidative stress and perivascular inflammation, critical contributors to perivascular fibrosis and accelerated vascular ageing. Oxidative stress can promote vascular inflammation, creating options for potential use of NADPH oxidase inhibitors in pharmacological targeting of perivascular inflammation and its consequences. Accordingly, we characterized age-related changes in oxidative stress and immune cell infiltration in normotensive (WKY) and spontaneously hypertensive rats (SHRs). Subsequently, we used pharmacological inhibitors of Nox1 (ML171) and Nox1/Nox4 (GKT137831; 60 mg/kg), to modulate NADPH oxidase activity at the early stage of spontaneous hypertension and investigated their effects on perivascular inflammation and fibrosis. RESULTS: Ageing was associated with a progressive increase of blood pressure as well as an elevation of the total number of leukocytes, macrophages and NK cells infiltrating perivascular adipose tissue (PVAT) in SHRs but not in WKY. At 1 month of age, when blood pressure was not yet different, only perivascular NK cells were significantly higher in SHR. Spontaneous hypertension was also accompanied by the higher perivascular T cell accumulation, although this increase was age independent. Aortic Nox1 and Nox2 mRNA expression increased with age only in SHR but not in WKY, while age-related increase of Nox4 mRNA in the vessels has been observed in both groups, it was more pronounced in SHRs. At early stage of hypertension (3-months) the most pronounced differences were observed in Nox1 and Nox4. Surprisingly, GKT137831, dual inhibitor of Nox1/4, therapy increased both blood pressure and perivascular macrophage infiltration. Mechanistically, this was linked to increased expression of proinflammatory chemokines expression (CCL2 and CCL5) in PVAT. This inflammatory response translated to increased perivascular fibrosis. This effect was likely Nox4 dependent as the Nox1 inhibitor ML171 did not affect the development of spontaneous hypertension, perivascular macrophage accumulation, chemokine expression nor adventitial collagen deposition. In summary, spontaneous hypertension promotes ageing-associated perivascular inflammation which is exacerbated by Nox4 but not Nox1 pharmacological inhibition.

Effect of pirfenidone on gastric emptying in a rat model.

INTRODUCTION: Gastrointestinal (GI) adverse events (AEs) are commonly reported in patients with idiopathic pulmonary fibrosis who are treated with pirfenidone. Taking pirfenidone with a substantial amount of food or dividing the dose over the course of a meal has been reported to reduce the frequency of GI AEs in clinical practice. In humans, the maximum plasma concentration (Cmax) of pirfenidone was reduced when the drug was taken with food compared with the fasting state, and the lower Cmax was associated with a reduction in GI AE rates. In this study, the effects of the divided-dose approach and timing of pirfenidone administration relative to meal intake on gastric emptying were assessed using a rat model. The aim of this study was to investigate whether modification of dosing regimens could minimize pirfenidone's effect on inhibition of gastric emptying. METHODS: Gastric emptying was assessed in male Sprague-Dawley rats after administration of a test meal by weighing stomach contents at various time points up to 120 min after the meal. Pirfenidone was administered via oral gavage either as a single-bolus dose of 30 mg/kg or as divided doses of 3 × 10 mg/kg at intervals ranging from 10 to 30 min for a total duration of 30 to 90 min. In addition, the test meal was given either at 30 min before, coincident with, or 30 min following pirfenidone oral administration. RESULTS: Administration of an oral 30-mg/kg single-bolus dose of pirfenidone with a meal resulted in a statistically significant decrease in gastric emptying in a rat model. The effect of pirfenidone on decreasing gastric emptying was lessened when the same total dose (i.e., 30 mg/kg) was administered as 3 divided doses (i.e., 3 × 10 mg/kg) over intervals up to 30 min in between each divided dose. Pharmacokinetic simulation suggested that a divided-dosing regimen would decrease pirfenidone Cmax relative to single-bolus administration. When the same single-bolus dose of 30 mg/kg was administered 30 min following a meal rather than coincident with a meal, pirfenidone's effect on decreasing gastric emptying was reduced to the same extent as when the dose was divided as 3 × 10 mg/kg over a 90-min period. CONCLUSIONS: Administration of pirfenidone 30 min after a meal as a single-bolus dose or a divided dose over a 90-min period blunted pirfenidone's effect on inhibition of gastric emptying in rats compared with pirfenidone administration as a single-bolus dose coincident with a meal. Decreased gastric emptying, which is associated with pirfenidone administration, may be one of the contributing factors leading to GI tolerability issues associated with pirfenidone use in humans. Modification of the dosing regimen diminished this impact and may provide insight into possible mitigation strategies to minimize GI-related toxicities in the clinic.

Apixaban Versus Warfarin for Mechanical Heart Valve Thromboprophylaxis in a Swine Aortic Heterotopic Valve Model.

OBJECTIVE: Warfarin is the current standard for oral anticoagulation therapy in patients with mechanical heart valves, yet optimal therapy to maximize anticoagulation and minimize bleeding complications requires routine coagulation monitoring, possible dietary restrictions, and drug interaction monitoring. As alternatives to warfarin, oral direct acting factor Xa inhibitors are currently approved for the prophylaxis and treatment of venous thromboembolism and reduction of stroke and systemic embolization. However, no in vivo preclinical or clinical studies have been performed directly comparing oral factor Xa inhibitors such as apixaban to warfarin, the current standard of therapy. APPROACH AND RESULTS: A well-documented heterotopic aortic valve porcine model was used to test the hypothesis that apixaban has comparable efficacy to warfarin for thromboprophylaxis of mechanical heart valves. Sixteen swine were implanted with a bileaflet mechanical aortic valve that bypassed the ligated descending thoracic aorta. Animals were randomized to 4 groups: control (no anticoagulation; n=4), apixaban oral 1 mg/kg twice a day (n=5), warfarin oral 0.04 to 0.08 mg/kg daily (international normalized ratio 2-3; n=3), and apixaban infusion (n=4). Postmortem valve thrombus was measured 30 days post-surgery for control-oral groups and 14 days post-surgery for the apixaban infusion group. Control thrombus weight (mean) was significantly different (1422.9 mg) compared with apixaban oral (357.5 mg), warfarin (247.1 mg), and apixiban 14-day infusion (61.1 mg; P<0.05). CONCLUSIONS: Apixaban is a promising candidate and may be a useful alternative to warfarin for thromboprophylaxis of mechanical heart valves. Unlike warfarin, no adverse bleeding events were observed in any apixaban groups.

Bruton's Tyrosine Kinase Small Molecule Inhibitors Induce a Distinct Pancreatic Toxicity in Rats.

Bruton's tyrosine kinase (BTK) is a member of the Tec family of cytoplasmic tyrosine kinases involved in B-cell and myeloid cell signaling. Small molecule inhibitors of BTK are being investigated for treatment of several hematologic cancers and autoimmune diseases. GDC-0853 ((S)-2-(3'-(hydroxymethyl)-1-methyl-5-((5-(2-methyl-4-(oxetan-3-yl)piperazin-1-yl)pyridin-2-yl)amino)-6-oxo-1,6-dihydro-[3,4'-bipyridin]-2'-yl)-7,7-dimethyl-3,4,7,8-tetrahydro-2H-cyclopenta[4,5]pyrrolo[1,2-a]pyrazin-1(6H)-one) is a selective and reversible oral small-molecule BTK inhibitor in development for the treatment of rheumatoid arthritis and systemic lupus erythematosus. In Sprague-Dawley (SD) rats, administration of GDC-0853 and other structurally diverse BTK inhibitors for 7 days or longer caused pancreatic lesions consisting of multifocal islet-centered hemorrhage, inflammation, fibrosis, and pigment-laden macrophages with adjacent lobular exocrine acinar cell atrophy, degeneration, and inflammation. Similar findings were not observed in mice or dogs at much higher exposures. Hemorrhage in the peri-islet vasculature emerged between four and seven daily doses of GDC-0853 and was histologically similar to spontaneously occurring changes in aging SD rats. This suggests that GDC-0853 could exacerbate a background finding in younger animals. Glucose homeostasis was dysregulated following a glucose challenge; however, this occurred only after 28 days of administration and was not directly associated with onset or severity of pancreatic lesions. There were no changes in other common serum biomarkers assessing endocrine and exocrine pancreatic function. Additionally, these lesions were not readily detectable via Doppler ultrasound, computed tomography, or magnetic resonance imaging. Our results indicate that pancreatic lesions in rats are likely a class effect of BTK inhibitors, which may exacerbate an islet-centered pathology that is unlikely to be relevant to humans.

Development of an Improved Inhalable Powder Formulation of Pirfenidone by Spray-Drying: In Vitro Characterization and Pharmacokinetic Profiling.

PURPOSE: Previously, a respirable powder (RP) formulation of pirfenidone (PFD) was developed for reducing phototoxic risk; however, PFD-RP demonstrated unacceptable in vitro inhalation performance. The present study aimed to develop a new RP system of PFD with favorable inhalation properties by spray-drying method. METHODS: Spray-dried PFD (SD/PFD) was prepared by spray-drying with L-leucine, and the physicochemical properties and efficacy in an antigen-sensitized airway inflammation model were assessed. A pharmacokinetic study was also conducted after intratracheal and oral administration of PFD formulations. RESULTS: Regarding powder characterization, SD/PFD had dimpled surface with the mean diameter of 1.793 µm. In next generation impactor analysis, SD/PFD demonstrated high in vitro inhalation performance without the need of carrier particles, and the fine particle fraction of SD/PFD was calculated to be 62.4%. Insufflated SD/PFD (0.3 mg-PFD/rat) attenuated antigen-evoked inflammatory events in the lung, including infiltration of inflammatory cells and myeloperoxidase activity. Systemic exposure level of PFD after insufflation of SD/PFD at the pharmacologically effective dose was 600-fold lower than that after oral administration of PFD at the phototoxic dose. CONCLUSION: SD/PFD would be suitable for inhalation, and the utilization of an RP system with SD/PFD would provide a safer medication compared with oral administration of PFD.

Iodine catalyzed simple and efficient synthesis of antiproliferative 2-pyridones.

A simple and efficient method for the selective synthesis of 2-pyrdones from 4H-pyrans using iodine as catalyst and ethanol as solvent was developed. The present method is equally effective for both aromatic and hetero aromatic ring containing 4H-pyrans. The compatibility with various functional groups, mild reaction conditions, high yields and application of inexpensive, readily and easily available iodine as catalyst and formation of 2-pyridones as major products are the advantages of the present procedure. In vitro antiproliferative activity of the final synthesized compounds was evaluated with four different human cancer cell lines (Lung adenocarcinoma-A549, Hepatocarcinoma-HepG2, Breast carcinoma-MCF-7 and Ovarian carcinoma-SKOV3) and normal human lung fibroblast cell line (MRC-5). Compounds 2b showed better inhibition against MCF-7, HepG2 and A549 cell lines (IC50 8.00 ± 0.11, 11.93 ± 0.01 and 15.85 ± 0.04 µM, respectively) as compared with doxorubicin and also 2e showed moderate inhibition against MCF-7, HepG2 (IC50 9.32 ± 0.21 and 20.22 ± 0.01 µM, respectively, cell lines, respectively) as compared with doxorubicin. As many clinically used antiproliferative agents induce apoptosis in cancer cells hence, the 2-pyridone analogues were also tested for their ability to induce apoptosis in MCF-7 cells using the caspases-3 and -9 assays.

Chlorpyrifos exposure in farmers and urban adults: Metabolic characteristic, exposure estimation, and potential effect of oxidative damage.

Chlorpyrifos is a widely used organophosphorus pesticide that efficiently protects crops against pests. However, recent studies suggest that severe exposure to chlorpyrifos may present adverse health effects in human. To analyze the exposure level and metabolic characteristics of chlorpyrifos pesticide in urban adults and farmers with/without occupation pesticide contact, the occurrence of urinary chlorpyrifos and methyl chlorpyrifos (CP-me), as well as their metabolite, 3,5,6-trichloro-2-pyridinol (TCPy), was determined in farmers of an agricultural village in China, and in urban adults of a nearby town. The geometric mean (GM) concentrations of TCPy, which is the major marker of chlorpyrifos exposure, were 4.29 and 7.57µg/g-creatinine in urban adults and farmers before pesticide application, respectively. Chlorpyrifos spraying significantly increased the concentrations of urinary TCPy. In the first day after spraying, a GM concentration of 43.7µg/g-creatinine was detected in the urine specimens from farmers, which decreased to 38.1 and 22.8µg/g-creatinine in the second and third day after chlorpyrifos spraying. The ratio of TCPy and its parent compounds, i.e. chlorpyrifos and CP-me, was positively associated with the sum concentration of urinary chlorpyrifos, CP-me, and TCPy, suggesting the increasing metabolic efficiency of chlorpyrifos to TCPy at higher chlorpyrifos exposure levels. To estimate the farmers' occupational exposure to chlorpyrifos pesticide, a new model based on the fitted first-order elimination kinetics of TCPy was established. Occupational chlorpyrifos exposure in a farmer was estimated to be 3.70µg/kg-bw/day (GM), which is an exposure level that is higher than the recommended guideline levels. Significant increase of urinary 8-hydroxydeoxyguanosine (8-OHdG) was observed on the first day after chlorpyrifos spraying, which indicates a potential oxidative damage in farmers. However, urinary 8-OHdG returned to its baseline level within two days.

Assessment of 8-methosypsoralen, lomefloxacin, sparfloxacin, and Pirfenidone phototoxicity in Long-Evans rats.

Phototoxicity has a strong impact on drug development. Although several animal models have been developed to quantitatively assess human risks, none have been validated for standardized use. In this study, we validated an in vivo phototoxicity model using Long-Evans (LE) rats treated with 4 well-known phototoxic drugs, namely 8-methoxypsoralen, lomefloxacin, sparfloxacin, and pirfenidone. Daily macroscopic observations of skin and eyes, ophthalmological examinations 4 days after dosing, and blood sampling for toxicokinetics (TKs) were performed after exposure of treated animals to ultraviolet, and dose-dependent eye and/or skin reactions were noted for all compounds. Margins of safety were calculated when possible and correlated well with known relative phototoxicity of the 4 compounds. We conclude that the present in vivo phototoxicity assay using LE rats with TK analysis can be used to quantitatively predict the risk of pharmaceutical phototoxicity in humans.

Sodium 3,5,6-trichloropyridin-2-ol poisoning: report of four cases.

Sodium 3,5,6-trichloropyridin-2-ol (STCP) is an important intermediate for synthesizing organophosphate insecticide chlorpyrifos. At present, chlorpyrifos is one of the world's largest species of pesticide products. Many studies have focused on the toxicity of chlorpyrifos, but few reports have looked at the toxicity mechanism of STCP. Even fewer studies have looked at STCP poisoning. With increasing production and usage of STCP, the chances of such poisoning will increase. In this study, we present a report on four workers who helped in the industrial manufacture of STCP and who were affected by exposure to it. We hope that these case studies will provide a foundation for further research into STCP.

Proximal discrepancies in intrinsic atomic interaction determines comparative in vivo biotoxicity of Chlorpyrifos and 3,5,6-trichloro-2-pyridinol in embryonic zebrafish.

Bioaccumulation of Chlorpyrifos (CP) as pesticides due to their aggrandized use in agriculture has raised serious concern on the health of ecosystem and human beings. Moreover, their degraded products like 3,5,6-trichloro-2-pyridinol (TCP) has enhanced the distress due to their unpredictable biotoxicity. This study evaluates and deduce the comparative in vivo mechanistic biotoxicity of CP and TCP with zebrafish embryos through experimental and computational approach. Experimental cellular and molecular analysis showed higher induction of morphological abnormalities, oxidative stress and apoptosis in TCP exposed embryos compared to CP exposure due to upregulation of metabolic enzymes like Zhe1a, Sod1 and p53. Computational analysis excavated the differential discrepancies in intrinsic atomic interaction as a reason of disparity in biotoxicity of CP and TCP. The mechanistic differences were deduced due to the differential accumulation and internalisation leading to variable interaction with metabolic enzymes for oxidative stress and apoptosis causing physiological and morphological abnormalities. The study unravelled the information of in vivo toxicity at cellular and molecular level to advocate the attention of taking measures for management of CP as well as TCP for environmental and human health.

Pesticide metabolite 3, 5, 6-trichloro-2-pyridinol causes massive damage to the cochlea resulting in hearing loss in adult mice.

Pesticides are a group of extensively used man-made chemicals with high toxicity and strong residues, which are closely related to hearing health. Pesticide metabolite 3, 5, 6-Trichloro-2-pyridinol (TCP) exposure leads to neurotoxicity and auditory cell toxicity. However, whether TCP causes damage to hearing in adult mice is not clear. In this study, adult male C57BL/6 mice continuously exposed to TCP for 21 days showed a dose-dependent elevation of hearing threshold. Outer hair cells and spiral neuron cells were lost in a dose-dependent manner. Type I and V of spiral ligament were severely shrunk and stria vascularis were thinned in mice after 50 and 150 mg/kg TCP exposure. Similarly, ROS levels in the cochlea were significantly increased whereas the activities of anti-oxidation enzymes were decreased after TCP exposure. The expression level of Na+/K+ ATPase was decreased, resulting in cochlear potential disruption. Levels of inflammatory factors (TNF-α and IL-1ß), γ-H2AX, and pro-apoptotic-related factors (Bax and cleaved-Caspase 3) were elevated, respectively. These results suggest that TCP can cause oxidative stress, inflammation, and imbalance of cochlear potential in the cochlea, induce cochlear DNA damage and apoptosis, and cause cochlear morphological changes, eventually leading to impaired hearing function.

Phenyl substituted 3-hydroxypyridin-2(1H)-ones: inhibitors of influenza A endonuclease.

Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase is recognized as an attractive target for the development of new agents for the treatment of influenza infection. Our earlier study employing small molecule fragment screening using a high-resolution crystal form of pandemic 2009 H1N1 influenza A endonuclease domain (PAN) resulted in the identification of 5-chloro-3-hydroxypyridin-2(1H)-one as a bimetal chelating ligand at the active site of the enzyme. In the present study, several phenyl substituted 3-hydroxypyridin-2(1H)-one compounds were synthesized and evaluated for their ability to inhibit the endonuclease activity as measured by a high-throughput fluorescence assay. Two of the more potent compounds in this series, 16 and 18, had IC50 values of 11 and 23nM in the enzymatic assay, respectively. Crystal structures revealed that these compounds had distinct binding modes that chelate the two active site metal ions (M1 and M2) using only two chelating groups. The SAR and the binding mode of these 3-hydroxypyridin-2-ones provide a basis for developing a new class of anti-influenza drugs.

Health risk characterization of chlorpyrifos using epidemiological dose-response data and probabilistic techniques: a case study with rice farmers in Vietnam.

Various methods for risk characterization have been developed using probabilistic approaches. Data on Vietnamese farmers are available for the comparison of outcomes for risk characterization using different probabilistic methods. This article addresses the health risk characterization of chlorpyrifos using epidemiological dose-response data and probabilistic techniques obtained from a case study with rice farmers in Vietnam. Urine samples were collected from farmers and analyzed for trichloropyridinol (TCP), which was converted into absorbed daily dose of chlorpyrifos. Adverse health response doses due to chlorpyrifos exposure were collected from epidemiological studies to develop dose-adverse health response relationships. The health risk of chlorpyrifos was quantified using hazard quotient (HQ), Monte Carlo simulation (MCS), and overall risk probability (ORP) methods. With baseline (prior to pesticide spraying) and lifetime exposure levels (over a lifetime of pesticide spraying events), the HQ ranged from 0.06 to 7.1. The MCS method indicated less than 0.05% of the population would be affected while the ORP method indicated that less than 1.5% of the population would be adversely affected. With postapplication exposure levels, the HQ ranged from 1 to 32.5. The risk calculated by the MCS method was that 29% of the population would be affected, and the risk calculated by ORP method was 33%. The MCS and ORP methods have advantages in risk characterization due to use of the full distribution of data exposure as well as dose response, whereas HQ methods only used the exposure data distribution. These evaluations indicated that single-event spraying is likely to have adverse effects on Vietnamese rice farmers.

Cellular toxicity of nicotinamide metabolites.

There are almost 100 different substances called uremic toxins. Nicotinamide derivatives are known as new family of uremic toxins. These uremic compounds play a role in an increased oxidative stress and disturbances in cellular repair processes by inhibiting poly (ADP-ribose) polymerase activity. New members of this family were discovered and described. Their toxic properties were a subject of recent studies. This study evaluated the concentration of 4-pyridone-3-carboxamid-1-ß-ribonucleoside-triphosphate (4PYTP) and 4-pyridone-3-carboxamid-1-ß-ribonucleoside-monophosphate (4PYMP) in erythrocytes of patients with chronic renal failure. Serum and red blood cells were collected from chronic renal failure patients on conservative treatment, those treated with hemodialysis, and at different times from those who underwent kidney transplantation. Healthy volunteers served as a control group. Nicotinamide metabolites were determined using liquid chromatography with mass spectrometry based on originally discovered and described method. Three novel compounds were described: 4-pyridone-3-carboxamid-1-ß-ribonucleoside (4PYR), 4PYMP, and 4PYTP. 4PYR concentration was elevated in the serum, whereas 4PYMP and 4PYTP concentrations were augmented in erythrocytes of dialysis patients. Interestingly, concentrations of these compounds were less elevated during the treatment with erythropoietin-stimulating agents (ESAs). After successful kidney transplantation, concentrations of 4PYR and 4PYMP normalized according to the graft function, whereas that of 4PYTP was still elevated. During the incubation of erythrocytes in the presence of 4PYR, concentration of 4PYMP rose very rapidly while that of 4PYTP increased slowly. Therefore, we hypothesized that 4PYR, as a toxic compound, was actively absorbed by erythrocytes and metabolized to the 4PYMP and 4PYTP, which may interfere with function and life span of these cells.

MITOGEN-ACTIVATED PROTEIN INHIBITORS: FULL-FIELD ELECTRORETINOGRAM DEMONSTRATING GENERALIZED RETINAL DYSFUNCTION.

PURPOSE: To report a patient with generalized retinal toxicity to mitogen-activated protein inhibitors. METHODS: Retrospective case report. RESULTS: Full-field electroretinogram findings indicate a generalized toxicity to the use of the mitogen-activated protein inhibitor trametinib. There was an improved response and resolution of serous detachments after decreasing the dose. CONCLUSION: Mitogen-activated protein inhibitors may affect global retinal function, as opposed to the serous detachments that are concentrated in the posterior pole. This may be of importance in further understanding the underlying pathologic mechanisms.

Dabrafenib- and trametinib-associated glomerular toxicity: A case report.

RATIONALE: Combined treatment with dabrafenib, a B-RAF inhibitor, and trametinib, a mitogen-activated protein kinase inhibitor, is an effective option for patients with metastatic melanoma. A few cases of acute kidney injury associated with tubulointerstitial nephritis and 1 case of nephrotic syndrome have been reported in patients on this drug combination; however, progressive renal injury has not been reported. In this case study, we report a patient with metastatic melanoma who developed glomerular capillary endothelial toxicity and progressive glomerular sclerosis during combination therapy. PATIENT CONCERN: Our patient was an 80-year-old woman with a history of type 2 diabetes and chronic kidney disease. DIAGNOSIS AND INTERVENTION: She was diagnosed with metastatic melanoma and commenced combination therapy with dabrafenib and trametinib. OUTCOMES: Her renal function progressively deteriorated; by month 20 after treatment commencement, her serum creatinine level had increased from 1.59 to 3.74 mg/dL. The first kidney biopsy revealed marked glomerular and endothelial cell damage. Her medication was stopped, but no improvement was evident. At 5 months after the first biopsy, her serum creatinine level had increased to 5.46 mg/dL; a second kidney biopsy revealed focal segmental glomerular sclerosis and marked tubulointerstitial fibrosis. She was started on hemodialysis. LESSONS: We describe a patient with a metastatic melanoma who developed progressive kidney failure during treatment with dabrafenib and trametinib. The most prominent microscopy findings were glomerular endothelial damage in the initial kidney biopsy and accelerated glomerular sclerosis and tubulointerstitial fibrosis in the follow-up biopsy. We hypothesize that a decreased renal reserve and impairment of kidney repair capacity caused by inhibition of B-RAF, a downstream mediator of vascular endothelial growth factor, may explain the progressive kidney injury.

Real-Life Impact of Drug Toxicity on Dolutegravir Tolerability: Clinical Practice Data from a Multicenter Italian Cohort.

Dolutegravir (DTG) is currently one of the most used Integrase inhibitors (INI) in antiretroviral therapies (ARV) in both naïve and experienced people living with HIV (PLWHIV). We analyzed a multicenter cohort of PLWHIV, both naïve and experienced, starting an ARV including DTG. We enrolled 3775 PLWHIV: 2763 (73.2%) were males, with a median age of 50 years. During 9890.7 PYFU, we observed 930 discontinuations (9.4 per 100 PYFU). Estimated probabilities of maintaining DTG at three and five years were 75.1% and 67.2%, respectively. Treatment-naïve pts showed a lower probability of maintaining DTG at three and five years compared to treatment-experienced PLWHIV (log-rank p < 0.001). At a multivariate analysis, a longer time of virological suppression (aHR 0.994, p < 0.001) and having experienced a previous virological failure (aHR 0.788, p = 0.016) resulted protective against DTG discontinuation. Most discontinuations (84.0%) happened within the first 12 months of DTG initiation, in particular, 92.2% of discontinuations due to neuropsychiatric toxicity were observed in the first year. Our data confirm the overall good tolerability of DTG in clinical practice, with a low rate of discontinuations. CNS toxicity resulted the main reason for DTG discontinuation, with most related interruptions happening in the first year from DTG introduction.