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Cardiovascular Research Aug 2022Hypoxic pulmonary vasoconstriction (HPV) is a physiological response to alveolar hypoxia that diverts blood flow from poorly ventilated to better aerated lung areas to...
AIMS
Hypoxic pulmonary vasoconstriction (HPV) is a physiological response to alveolar hypoxia that diverts blood flow from poorly ventilated to better aerated lung areas to optimize ventilation-perfusion matching. Yet, the exact sensory and signalling mechanisms by which hypoxia triggers pulmonary vasoconstriction remain incompletely understood. Recently, ATP release via pannexin 1 (Panx1) and subsequent signalling via purinergic P2Y receptors has been identified as regulator of vasoconstriction in systemic arterioles. Here, we probed for the role of Panx1-mediated ATP release in HPV and chronic hypoxic pulmonary hypertension (PH).
METHODS AND RESULTS
Pharmacological inhibition of Panx1 by probenecid, spironolactone, the Panx1 specific inhibitory peptide (10Panx1), and genetic deletion of Panx1 specifically in smooth muscle attenuated HPV in isolated perfused mouse lungs. In pulmonary artery smooth muscle cells (PASMCs), both spironolactone and 10Panx1 attenuated the increase in intracellular Ca2+ concentration ([Ca2+]i) in response to hypoxia. Yet, genetic deletion of Panx1 in either endothelial or smooth muscle cells did not prevent the development of PH in mice. Unexpectedly, ATP release in response to hypoxia was not detectable in PASMC, and inhibition of purinergic receptors or ATP degradation by ATPase failed to attenuate HPV. Rather, transient receptor potential vanilloid 4 (TRPV4) antagonism and Panx1 inhibition inhibited the hypoxia-induced [Ca2+]i increase in PASMC in an additive manner, suggesting that Panx1 regulates [Ca2+]i independently of the ATP-P2Y-TRPV4 pathway. In line with this notion, Panx1 overexpression increased the [Ca2+]i response to hypoxia in HeLa cells.
CONCLUSION
In the present study, we identify Panx1 as novel regulator of HPV. Yet, the role of Panx1 in HPV was not attributable to ATP release and downstream signalling via P2Y receptors or TRPV4 activation, but relates to a role of Panx1 as direct or indirect modulator of the PASMC Ca2+ response to hypoxia. Panx1 did not affect the development of chronic hypoxic PH.
Topics: Adenosine Triphosphate; Animals; Calcium; Connexins; HeLa Cells; Humans; Hypertension, Pulmonary; Hypoxia; Lung; Mice; Nerve Tissue Proteins; Pulmonary Artery; Spironolactone; TRPV Cation Channels; Vasoconstriction
PubMed: 34668529
DOI: 10.1093/cvr/cvab326 -
Neurobiology of Disease Aug 2023Loss of dopaminergic midbrain neurons perturbs l-serine and d-serine homeostasis in the post-mortem caudate putamen (CPu) of Parkinson's disease (PD) patients. However,...
Loss of dopaminergic midbrain neurons perturbs l-serine and d-serine homeostasis in the post-mortem caudate putamen (CPu) of Parkinson's disease (PD) patients. However, it is unclear whether the severity of dopaminergic nigrostriatal degeneration plays a role in deregulating serine enantiomers' metabolism. Here, through high-performance liquid chromatography (HPLC), we measured the levels of these amino acids in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys and MPTP-plus-probenecid (MPTPp)-treated mice to determine whether and how dopaminergic midbrain degeneration affects the levels of serine enantiomers in various basal ganglia subregions. In addition, in the same brain regions, we measured the levels of key neuroactive amino acids modulating glutamatergic neurotransmission, including l-glutamate, glycine, l-aspartate, d-aspartate, and their precursors l-glutamine, l-asparagine. In monkeys, MPTP treatment produced severe denervation of nigrostriatal dopaminergic fibers (⁓75%) and increased the levels of serine enantiomers in the rostral putamen (rPut), but not in the subthalamic nucleus, and the lateral and medial portion of the globus pallidus. Moreover, this neurotoxin significantly reduced the protein expression of the astrocytic serine transporter ASCT1 and the glycolytic enzyme GAPDH in the rPut of monkeys. Conversely, concentrations of d-serine and l-serine, as well as ASCT1 and GAPDH expression were unaffected in the striatum of MPTPp-treated mice, which showed only mild dopaminergic degeneration (⁓30%). These findings unveil a link between the severity of dopaminergic nigrostriatal degeneration and striatal serine enantiomers concentration, ASCT1 and GAPDH expression. We hypothesize that the up-regulation of d-serine and l-serine levels occurs as a secondary response within a homeostatic loop to support the metabolic and neurotransmission demands imposed by the degeneration of dopaminergic neurons.
Topics: Mice; Animals; Serine; 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Dopamine; Corpus Striatum; Mesencephalon; Amino Acids; Putamen; Homeostasis
PubMed: 37451474
DOI: 10.1016/j.nbd.2023.106226 -
British Journal of Clinical Pharmacology Oct 2018The primary aim of this study was to assess the individual effects of probenecid and cimetidine on mirogabalin exposure. (Randomized Controlled Trial)
Randomized Controlled Trial
AIMS
The primary aim of this study was to assess the individual effects of probenecid and cimetidine on mirogabalin exposure.
METHODS
This phase 1, open-label, crossover study randomized healthy adults to receive three treatment regimens, each separated by ≥5-day washout: a single oral dose of mirogabalin 15 mg on day 2, mirogabalin 15 mg on day 2 plus probenecid 500 mg every 6 h from days 1 to 4, and mirogabalin 15 mg on day 2 plus cimetidine 400 mg every 6 h from days 1 to 4.
RESULTS
Coadministration of mirogabalin with probenecid or cimetidine increased the maximum and total mirogabalin exposure. The geometric mean ratios of C and AUC (90% CI) with and without coadministration of probenecid were 128.7% (121.9-135.7%) and 176.1% (171.9-180.3%), respectively. The geometric mean ratios of C and AUC (90% CI) with and without coadministration of cimetidine were 117.1% (111.0-123.6%) and 143.7% (140.3-147.2%), respectively. Mean (standard deviation) renal clearance of mirogabalin (l h ) was substantially slower after probenecid [6.67 (1.53)] or cimetidine [7.17 (1.68)] coadministration, compared with mirogabalin alone [11.3 (2.39)]. Coadministration of probenecid or cimetidine decreased mirogabalin mean (standard deviation) apparent total body clearance [10.5 (2.33) and 12.8 (2.67) l h , respectively, vs. 18.4 (3.93) for mirogabalin alone].
CONCLUSIONS
A greater magnitude of change in mirogabalin exposure was observed when coadministered with a drug that inhibits both renal and metabolic clearance (probenecid) vs. a drug that only affects renal clearance (cimetidine). However, as the increase in exposure is not clinically significant (>2-fold), no a priori dose adjustment is recommended.
Topics: Administration, Oral; Adult; Area Under Curve; Bridged Bicyclo Compounds; Cimetidine; Cross-Over Studies; Diabetic Neuropathies; Dose-Response Relationship, Drug; Drug Interactions; Drug Therapy, Combination; Female; Healthy Volunteers; Herpes Zoster; Humans; Male; Metabolic Clearance Rate; Middle Aged; Neuralgia; Probenecid; Renal Elimination
PubMed: 29920736
DOI: 10.1111/bcp.13674 -
Cancers Nov 2021L-type amino acid transporter 1 (LAT1) might be a useful target for tumor therapy since it is highly expressed in various types of cancers. We previously developed an...
L-type amino acid transporter 1 (LAT1) might be a useful target for tumor therapy since it is highly expressed in various types of cancers. We previously developed an astatine-211 (At)-labeled amino acid derivative, 2-At-astato-α-methyl-L-phenylalanine (2-At-AAMP), and demonstrated its therapeutic potential for LAT1-positive cancers. However, the therapeutic effect of 2-At-AAMP was insufficient, probably due to its low tumor retention. The preloading of probenecid, an organic anion transporter inhibitor, can delay the clearance of some amino acid tracers from the blood and consequently increase their accumulation in tumors. In this study, we evaluated the effect of probenecid preloading on the biodistribution and therapeutic effect of 2-At-AAMP in mice. In biodistribution studies, the blood radioactivity of 2-At-AAMP significantly increased with probenecid preloading. Consequently, the accumulation of 2-At-AAMP in tumors was significantly higher with probenecid than without probenecid loading. In a therapeutic study, tumor growth was suppressed by 2-At-AAMP with probenecid, and the tumor volume was significantly lower in the treatment group than in the untreated control group from day 2 to day 30 (end of the follow-up period) after treatment. These results indicate that probenecid loading could improve the therapeutic effect of 2-At-AAMP by increasing its accumulation in tumors.
PubMed: 34771676
DOI: 10.3390/cancers13215514 -
JCI Insight Apr 2024Chronic kidney disease (CKD) causes accumulation of uremic metabolites that negatively affect skeletal muscle. Tryptophan-derived uremic metabolites are agonists of the...
Chronic kidney disease (CKD) causes accumulation of uremic metabolites that negatively affect skeletal muscle. Tryptophan-derived uremic metabolites are agonists of the aryl hydrocarbon receptor (AHR), which has been shown to be activated in CKD. This study investigated the role of the AHR in skeletal muscle pathology of CKD. Compared with controls with normal kidney function, AHR-dependent gene expression (CYP1A1 and CYP1B1) was significantly upregulated in skeletal muscle of patients with CKD, and the magnitude of AHR activation was inversely correlated with mitochondrial respiration. In mice with CKD, muscle mitochondrial oxidative phosphorylation (OXPHOS) was markedly impaired and strongly correlated with the serum level of tryptophan-derived uremic metabolites and AHR activation. Muscle-specific deletion of the AHR substantially improved mitochondrial OXPHOS in male mice with the greatest uremic toxicity (CKD + probenecid) and abolished the relationship between uremic metabolites and OXPHOS. The uremic metabolite/AHR/mitochondrial axis in skeletal muscle was verified using muscle-specific AHR knockdown in C57BL/6J mice harboring a high-affinity AHR allele, as well as ectopic viral expression of constitutively active mutant AHR in mice with normal renal function. Notably, OXPHOS changes in AHRmKO mice were present only when mitochondria were fueled by carbohydrates. Further analyses revealed that AHR activation in mice led to significantly increased pyruvate dehydrogenase kinase 4 (Pdk4) expression and phosphorylation of pyruvate dehydrogenase enzyme. These findings establish a uremic metabolite/AHR/Pdk4 axis in skeletal muscle that governs mitochondrial deficits in carbohydrate oxidation during CKD.
Topics: Animals; Receptors, Aryl Hydrocarbon; Mice; Male; Renal Insufficiency, Chronic; Tryptophan; Muscle, Skeletal; Humans; Oxidative Phosphorylation; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; Mice, Inbred C57BL; Uremia; Mitochondria, Muscle; Basic Helix-Loop-Helix Transcription Factors; Female; Mice, Knockout; Cytochrome P-450 CYP1B1; Cytochrome P-450 CYP1A1; Middle Aged; Energy Metabolism; Disease Models, Animal
PubMed: 38652558
DOI: 10.1172/jci.insight.178372 -
Clinical Pharmacokinetics Nov 2022Pexidartinib is a novel oral small-molecule inhibitor that selectively targets colony-stimulating factor 1 receptor, KIT proto-oncogene receptor tyrosine kinase, and...
BACKGROUND AND OBJECTIVE
Pexidartinib is a novel oral small-molecule inhibitor that selectively targets colony-stimulating factor 1 receptor, KIT proto-oncogene receptor tyrosine kinase, and FMS-like tyrosine kinase 3 harboring an internal tandem duplication mutation. It is approved in the United States for the treatment of adult patients with symptomatic tenosynovial giant cell tumor (TGCT) associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Pexidartinib in vitro data indicate the potential for absorption- and metabolism-related drug-drug interactions (DDIs). The objective was to present a comprehensive DDI risk assessment of agents that can impact pexidartinib exposure by altering its absorption and metabolism potentially affecting efficacy and safety of pexidartinib.
METHODS
Four open-label crossover studies were performed to assess the effects of a pH modifier (esomeprazole), a strong cytochrome P450 (CYP) 3A4 inhibitor (itraconazole), a strong CYP3A/5'-diphospho-glucuronosyltransferase (UGT) inducer (rifampin), and a UGT inhibitor (probenecid) on the single-dose pharmacokinetics of pexidartinib. In addition, a physiologically based pharmacokinetic model was developed to predict the effect of a moderate CYP3A4 inhibitor (fluconazole) and a moderate CYP3A inducer (efavirenz) on the pharmacokinetics of pexidartinib.
RESULTS
Co-administration of pexidartinib with esomeprazole modestly decreased pexidartinib exposure (maximum plasma concentration [C], ng/mL: geometric mean ratio [90% confidence interval (CI)], 45.4% [36.8-55.9]; area under the drug plasma concentration-time curve from time 0 to infinity [AUC], ng•h/mL: geometric mean ratio [90% CI], 53.1% [47.4-59.3]), likely related to decreased solubility of pexidartinib at increased pH levels. As expected, the strong CYP3A4 inhibitor itraconazole increased pexidartinib exposure (C, ng/mL: geometric mean ratio [90% CI], 148.3% [127.8-172.0]; AUC, ng•h/mL: geometric mean ratio [90% CI], 173.0% [160.7-186.3]) while the strong CYP3A/UGT inducer rifampin decreased exposure (C, ng/mL: geometric mean ratio [90% CI], 67.1% [53.1-84.8]; AUC, ng•h/mL: geometric mean ratio [90% CI], 37.0% [30.6-44.8]). In addition, UGT inhibition increased pexidartinib exposure (C, ng/mL: geometric mean ratio [90% CI], 105.8% [92.4-121.0]; AUC, ng•h/mL: geometric mean ratio [90% CI], 159.8% [143.4-178.0]), consistent with the fact that pexidartinib is a substrate of the UGT1A4 enzyme, which is responsible for the generation of the major metabolite, ZAAD-1006a.
CONCLUSIONS
The physiologically based pharmacokinetic model predicted that a moderate CYP3A4 inhibitor and a moderate CYP3A inducer would produce modest increases and decreases, respectively, in pexidartinib exposure. These results provide a basis for pexidartinib dosing recommendations when administered concomitantly with drugs with drug-drug interaction potential, including dose adjustments when concomitant administration cannot be avoided.
CLINICAL TRIAL REGISTRATION
Probenecid: phase I trial, NCT03138759, 3 May, 2017; esomeprazole, itraconazole, rifampin: phase I trials, not registered with ClinicalTrials.gov.
Topics: Adult; Humans; Area Under Curve; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP3A Inducers; Cytochrome P-450 CYP3A Inhibitors; Drug Interactions; Esomeprazole; Healthy Volunteers; Itraconazole; Probenecid; Rifampin
PubMed: 36264536
DOI: 10.1007/s40262-022-01172-9 -
Seminars in Arthritis and Rheumatism Apr 2024There is uncertainty about the optimal time to start urate-lowering therapy (ULT) in the setting of a gout flare. The aim was to perform a systematic review and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
There is uncertainty about the optimal time to start urate-lowering therapy (ULT) in the setting of a gout flare. The aim was to perform a systematic review and meta-analysis of randomised controlled trials (RCTs) assessing the effects of ULT initiation during a gout flare.
METHODS
This systematic review was conducted in accordance with PRISMA methodology. MEDLINE, EMBASE and The Cochrane Library were searched for studies published between database inception to 1 March 2023. RCTs published in English that examined ULT initiation during a gout flare in adults ≥18 years were included. The quality of included studies was assessed using the revised Cochrane Risk of Bias tool 2.0. Data were extracted for the following outcomes: patient-rated pain score, duration of gout flare, recurrent gout flares, time to achieve target serum urate, adherence to ULT, patient satisfaction with treatment and adverse events. Meta-analyses were performed using Review Manager v5.4. This study is registered on PROSPERO, number CRD42023404680.
RESULTS
A total of 972 studies were identified and of these, six RCTs met the criteria for inclusion in the analysis. Three studies were assessed as having high risk of bias, one study as having some concerns, and two studies as having low risk of bias. In total, there were 445 pooled participants; 226 participants randomised to early initiation of ULT and 219 to placebo or delayed initiation of ULT. Allopurinol was used in three studies, febuxostat in two studies and probenecid in one study. Few participants (n = 62, 13.9 %) had tophaceous gout. Participants with renal impairment were excluded from most studies. There were no differences in patient-rated pain scores at baseline, days 3-4, days 7-8, day 10 or days 14-15 (p ≥ 0.42). Additionally, there was no significant difference in time to resolution of gout flare (standardised mean difference 0.77 days; 95 % CI -0.26 to 1.79; p = 0.14) or the risk of recurrent gout flare in the subsequent 28 to 30 days (RR 1.06; 95 % CI 0.59 to 1.92; p = 0.84). Adverse events were similar between groups. The included studies did not report time to achieve target serum urate, long-term adherence to ULT, or patient satisfaction with treatment.
CONCLUSION
There appears to be no evidence for harm or for benefit to initiating ULT during a gout flare. These findings have limited applicability to patients with tophaceous gout, or those with renal impairment.
Topics: Adult; Humans; Uric Acid; Gout Suppressants; Gout; Allopurinol; Pain; Randomized Controlled Trials as Topic
PubMed: 38215627
DOI: 10.1016/j.semarthrit.2024.152367 -
Current Therapeutic Research, Clinical... Dec 2014Olmesartan is an angiotensin II receptor antagonist and is effective and well tolerated in the treatment of arterial hypertension. Probenecid is a well-established...
BACKGROUND
Olmesartan is an angiotensin II receptor antagonist and is effective and well tolerated in the treatment of arterial hypertension. Probenecid is a well-established hypouricemic agent for the treatment of hyperuricemia and gout.
OBJECTIVE
The goal of this study was to examine the impact of coadministration of probenecid on the pharmacokinetic parameters and tolerability of olmesartan in healthy volunteers.
METHODS
In a randomized, open-label, 2-way crossover study, 12 volunteers received 2 oral treatments (olmesartan alone or olmesartan plus probenecid) separated by 4 days. Blood samples were obtained for a 48-hour pharmacokinetic evaluation after drug administration. Tolerability was assessed by monitoring vital signs and laboratory tests before and after administration of the study drug.
RESULTS
Pharmacokinetic parameters were evaluated in 6 male and 6 female healthy volunteers (mean age, 22 [range, 20-25] years]; weight, 56.0 [range, 51.0-60.0] kg). Probenecid coadministration increased olmesartan Css-av, AUC0→∞, and AUC0-48 by 40%, 50%, and 50%, respectively (P = 0.018, 0.000, 0.000, respectively), but there was no statistical significance for Tmax, t1/2, Css-max, and Css-min between olmesartan plus probenecid and olmesartan alone (P = 0.697, 0.053, 0.521, and 0.734, respectively). No serious adverse event (AE) was reported during the study. The proportion of volunteers with AEs in the olmesartan plus probenecid period (5 of 12 [42%]) was higher than that in the olmesartan-alone period (1 of 12 [8%]). All of the AEs during the olmesartan plus probenecid period were abnormal routine urine test results. The AE in olmesartan-alone period was dizziness. All AEs were classified as mild and considered to be at least possibly related to treatment. All volunteers recovered from the AEs by 2 weeks after the end of the study.
CONCLUSIONS
Probenecid increases the exposure speed of olmesartan by increasing the AUC0-48, AUC0→∞, and Css-av. The combined treatment of olmesartan medoxomil with probenecid may increase the occurrence of genitourinary side effects. ClinicalTrials.gov identifier: NCT01907373.
PubMed: 25067982
DOI: 10.1016/j.curtheres.2013.11.004 -
SLAS Discovery : Advancing Life... Mar 2021Glucose transporter 9 (GLUT9), which transports urate in an electrogenic and voltage-dependent manner, plays an important role in the maintenance of normal blood uric...
Glucose transporter 9 (GLUT9), which transports urate in an electrogenic and voltage-dependent manner, plays an important role in the maintenance of normal blood uric acid/urate levels. In the present study, we established a cell model based on the single-electrode patch-clamp technique for characterization of GLUT9 and explored the inhibitory effects of benzobromarone (BM) and probenecid (PB) on urate-induced currents in mouse GLUT9a (mGLUT9a)-expressing HEK-293T cells. The results showed that uric acid, rather than glucose perfusion, led to a rapid and large outward current by mGLUT9a in dose-, voltage-, and pH-dependent manners. BM prominently and irreversibly inhibited the uric acid-induced currents through mGLUT9a, and PB weakly and reversibly inhibited mGLUT9a. We found that depletion of K in the external solution significantly strengthened the blockade of BM on mGLUT9a. In addition, an enhanced inhibitory rate of BM was detected when the pH of the external solution was changed from 7.4 to 5.5, indicating that BM functions optimally in an acidic environment. In conclusion, the combination of the established cell model with patch-clamp techniques first revealed the function properties of GLUT9 inhibitors and may provide potential benefits to the study of GLUT9 inhibitors as antihyperuricemic or antigout agents.
Topics: Animals; Benzbromarone; Biological Transport; Gene Expression; Glucose Transport Proteins, Facilitative; Gout Suppressants; HEK293 Cells; Humans; Hydrogen-Ion Concentration; Membrane Potentials; Mice; Naphthalenes; Patch-Clamp Techniques; Plasmids; Potassium; Probenecid; Propionates; Pyridines; Transgenes; Uric Acid
PubMed: 32844721
DOI: 10.1177/2472555220949501 -
Biological & Pharmaceutical Bulletin 2020We investigated whether tramadol could suppress both neuropathic and inflammatory pain in mice at the same dose level. We also examined the effects of drugs metabolized...
We investigated whether tramadol could suppress both neuropathic and inflammatory pain in mice at the same dose level. We also examined the effects of drugs metabolized by glucuronidase, such as acetaminophen (ACAP), indomethacin, probenecid, and valproate, on the antinociceptive activity of tramadol. The administration of 5.6 or 10 mg/kg tramadol suppressed cuff-induced mechanical allodynia, but 10 mg/kg tramadol did not suppress complete Freund's adjuvant (CFA)-induced mechanical allodynia. Although neither tramadol (10 mg/kg) nor ACAP (100 mg/kg) alone produced an antinociceptive effect, their combination suppressed CFA-induced mechanical allodynia. Moreover, pretreatment naloxone, an opioid receptor antagonist, significantly attenuated the antinociceptive effects induced by the combination of tramadol and ACAP and slowed gastrointestinal transit. Similar to ACAP, the combination of tramadol and probenecid or valproate, which has the potential to inhibit uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT), also suppressed the CFA-induced mechanical allodynia and slowed gastrointestinal transit. We concluded that tramadol was more beneficial for the treatment of neuropathic pain than inflammatory pain. Furthermore, the antinociceptive effects of the tramadol and ACAP combination were mediated by the μ-opioid receptor, and were thought to be related, at least in part, to the accumulation of the active metabolite, M1.
Topics: Acetaminophen; Analgesics, Non-Narcotic; Analgesics, Opioid; Animals; Drug Synergism; Drug Therapy, Combination; Gastrointestinal Transit; Hyperalgesia; Inflammation; Male; Mice, Inbred C57BL; Neuralgia; Receptors, Opioid, mu; Tramadol
PubMed: 32612076
DOI: 10.1248/bpb.b20-00230