Amino acid derivative of probenecid potentiates apoptosis-inducing effects of vinblastine by increasing oxidative stress in a cancer cell-specific manner.

Many chemotherapeutic drugs suffer from multidrug resistance (MDR). Efflux transporters, namely ATP-binding cassettes (ABCs), that pump the drugs out of the cancer cells comprise one major reason behind MDR. Therefore, ABC inhibitors have been under development for ages, but unfortunately, without clinical success. In the present study, an l-type amino acid transporter 1 (LAT1)-utilizing derivative of probenecid (PRB) was developed as a cancer cell-targeted efflux inhibitor for P-glycoprotein (P-gp), breast cancer resistant protein (BCRP) and/or several multidrug resistant proteins (MRPs), and its ability to increase vinblastine (VBL) cellular accumulation and apoptosis-inducing effects were explored. The novel amino acid derivative of PRB (2) increased the VBL exposure in triple-negative human breast cancer cells (MDA-MB-231) and human glioma cells (U-87MG) by 10-68 -times and 2-5-times, respectively, but not in estrogen receptor-positive human breast cancer cells (MCF-7). However, the combination therapy had greater cytotoxic effects in MCF-7 compared to MDA-MB-231 cells due to the increased oxidative stress recorded in MCF-7 cells. The metabolomic study also revealed that compound 2, together with VBL, decreased the transport of those amino acids essential for the biosynthesis of endogenous anti-oxidant glutathione (GSH). Moreover, the metabolic differences between the outcomes of the studied breast cancer cell lines were explained by the distinct expression profiles of solute carriers (SLCs) that can be concomitantly inhibited. Therefore, attacking several SLCs simultaneously to change the nutrient environment of cancer cells can serve as an adjuvant therapy to other chemotherapeutics, offering an alternative to ABC inhibitors.

N-Acetylcysteine and Probenecid Adjuvant Therapy for Traumatic Brain Injury.

N-Acetylcysteine (NAC) has shown promise as a putative neurotherapeutic for traumatic brain injury (TBI). Yet, many such promising compounds have limited ability to cross the blood-brain barrier (BBB), achieve therapeutic concentrations in brain, demonstrate target engagement, among other things, that have hampered successful translation. A pharmacologic strategy for overcoming poor BBB permeability and/or efflux out of the brain of organic acid-based, small molecule therapeutics such as NAC is co-administration with a targeted or nonselective membrane transporter inhibitor. Probenecid is a classic ATP-binding cassette and solute carrier inhibitor that blocks transport of organic acids, including NAC. Accordingly, combination therapy using probenecid as an adjuvant with NAC represents a logical neurotherapeutic strategy for treatment of TBI (and other CNS diseases). We have completed a proof-of-concept pilot study using this drug combination in children with severe TBI-the Pro-NAC Trial (ClinicalTrials.gov NCT01322009). In this review, we will discuss the background and rationale for combination therapy with probenecid and NAC in TBI, providing justification for further clinical investigation.

Probenecid Relieves Cerebral Dysfunction of Sepsis by Inhibiting Pannexin 1-Dependent ATP Release.

Acute brain dysfunction and the following neurological manifestation are common complications in septic patients, which are associated with increased morbidity and mortality. However, the therapeutic strategy of this disorder remains a major challenge. Given the emerging role of a clinically approved drug, probenecid (PRB) has been recently identified as an inhibitor of pannexin 1 (PANX1) channel, which restrains extracellular ATP release-induced purinergic pathway activation and inflammatory response contributing to diverse pathological processes. In this study, we explored whether PRB administration attenuated neuroinflammatory response and cognitive impairment during sepsis. In mice suffered from cecal ligation and puncture (CLP)-induced sepsis, treatment with PRB improved memory retention and lessened behavioral deficits. This neuroprotective effect was coupled with restricted overproduction of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and interleukin (IL)-1ß in the hippocampus. Since this damped neuroinflammation was replicated by inhibition of ATP release, it suggested that PANX1 channel modulates a purinergic-related pathway contributing to the neurohistological damage. Therefore, we identified PRB could be a promising therapeutic approach for the therapy of cerebral dysfunction of sepsis.

Exploratory Application of Neuropharmacometabolomics in Severe Childhood Traumatic Brain Injury.

OBJECTIVES: To employ metabolomics-based pathway and network analyses to evaluate the cerebrospinal fluid metabolome after severe traumatic brain injury in children and the capacity of combination therapy with probenecid and N-acetylcysteine to impact glutathione-related and other pathways and networks, relative to placebo treatment. DESIGN: Analysis of cerebrospinal fluid obtained from children enrolled in an Institutional Review Board-approved, randomized, placebo-controlled trial of a combination of probenecid and N-acetylcysteine after severe traumatic brain injury (Trial Registration NCT01322009). SETTING: Thirty-six-bed PICU in a university-affiliated children's hospital. PATIENTS AND SUBJECTS: Twelve children 2-18 years old after severe traumatic brain injury and five age-matched control subjects. INTERVENTION: Probenecid (25 mg/kg) and N-acetylcysteine (140 mg/kg) or placebo administered via naso/orogastric tube. MEASUREMENTS AND MAIN RESULTS: The cerebrospinal fluid metabolome was analyzed in samples from traumatic brain injury patients 24 hours after the first dose of drugs or placebo and control subjects. Feature detection, retention time, alignment, annotation, and principal component analysis and statistical analysis were conducted using XCMS-online. The software "mummichog" was used for pathway and network analyses. A two-component principal component analysis revealed clustering of each of the groups, with distinct metabolomics signatures. Several novel pathways with plausible mechanistic involvement in traumatic brain injury were identified. A combination of metabolomics and pathway/network analyses showed that seven glutathione-centered pathways and two networks were enriched in the cerebrospinal fluid of traumatic brain injury patients treated with probenecid and N-acetylcysteine versus placebo-treated patients. Several additional pathways/networks consisting of components that are known substrates of probenecid-inhibitable transporters were also identified, providing additional mechanistic validation. CONCLUSIONS: This proof-of-concept neuropharmacometabolomics assessment reveals alterations in known and previously unidentified metabolic pathways and supports therapeutic target engagement of the combination of probenecid and N-acetylcysteine treatment after severe traumatic brain injury in children.

Inhibition of sterile danger signals, uric acid and ATP, prevents inflammasome activation and protects from alcoholic steatohepatitis in mice.

BACKGROUND & AIMS: The inflammasome is a well-characterized inducer of inflammation in alcoholic steatohepatitis (ASH). Inflammasome activation requires two signals for mature interleukin (IL)-1ß production. Here we asked whether metabolic danger signals trigger inflammasome activation in ASH. METHODS: Wild-type mice, ATP receptor 2x7 (P2rx7)-KO mice, or mice overexpressing uricase were fed Lieber-DeCarli ethanol or control diet. We also implemented a pharmacological approach in which mice were treated with probenecid or allopurinol. RESULTS: The sterile danger signals, ATP and uric acid, were increased in the serum and liver of alcohol-fed mice. Depletion of uric acid or ATP, or lack of ATP signaling attenuated ASH and prevented inflammasome activation and its major downstream cytokine, IL-1ß. Pharmacological depletion of uric acid with allopurinol provided significant protection from alcohol-induced inflammatory response, steatosis and liver damage, and additional protection was achieved in mice treated with probenecid, which depletes uric acid and blocks ATP-induced P2rx7 signaling. We found that alcohol-damaged hepatocytes released uric acid and ATP in vivo and in vitro and that these sterile danger signals activated the inflammasome in LPS-exposed liver mononuclear cells. CONCLUSIONS: Our data indicate that the second signal in inflammasome activation and IL-1ß production in ASH results from the endogenous danger signals, uric acid and ATP. Inhibition of signaling triggered by uric acid and ATP may have therapeutic implications in ASH.

High-dose oral amoxicillin plus probenecid is highly effective for syphilis in patients with HIV infection.

BACKGROUND: Intramuscular benzathine penicillin G (BPG) is widely used for the treatment of syphilis. However, BPG is not available in some countries. This study examined the effectiveness and safety of high-dose oral amoxicillin plus probenecid for the treatment of syphilis in patients with human immunodeficiency virus type 1 (HIV-1). METHODS: This retrospective observational study included 286 HIV-infected male patients with syphilis (median age, 36 years; median CD4 count, 389 cells/µL) who were treated with oral amoxicillin 3 g plus probenecid. Syphilis was diagnosed by both serum rapid plasma reagin (RPR) titers ≥8 and positive Treponema pallidum hemagglutination test. Patients with neurosyphilis diagnosed by cerebrospinal fluid examination were excluded. Successful treatment was defined as a at least 4-fold decrement in RPR titer. RESULTS: The overall treatment efficacy was 95.5% (95% confidence interval [CI], 92.4%-97.7%; 273/286 patients), and efficacy for primary, secondary, early latent, late latent, and unknown duration syphilis was 93.8% (95% CI, 68.1%-99.8%; 15/16), 97.3% (95% CI, 92.9%-99.2%; 142/146), 100% (95% CI, 90.5%-100%; 37/37), 85.7% (95% CI, 58.6%-96.4%; 18/21), and 92.4% (95% CI, 81.9%-97.3%; 61/66), respectively. Treatment duration was mostly 14-16 days (49.7%) or 28-30 days (34.3%), with efficacy of 94.4% (134/142) and 95.9% (94/98), respectively; 96.3% of successfully treated patients achieved a ≥4-fold decrement in RPR titer within 12 months. Adverse events were noted in 28 (9.8%) patients, and 25 of these (89.3%) were successfully treated. Only 6% of patients underwent lumbar puncture. CONCLUSIONS: The combination of oral amoxicillin 3 g plus probenecid was highly effective and tolerable for the treatment of syphilis in patients with HIV-1 infection.

Targeting TRPV1 and TRPV2 for potential therapeutic interventions in cardiovascular disease.

Cardiovascular disease is a leading cause of morbidity and mortality worldwide, encompassing a variety of cardiac and vascular conditions. Transient receptor potential vanilloid (TRPV) channels, specifically TRPV type 1 (TRPV1) and TRPV type 2 (TRPV2), are relatively recently described channels found throughout the body including within and around the cardiovascular system. They are activated by a variety of stimuli including high temperatures, stretch, and pharmacologic and endogenous ligands. The TRPV1 channel has been found to be an important player in the pathway of the detection of chest pain after myocardial injury. Activation of peripheral TRPV1 via painful stimuli or capsaicin has been shown to have cardioprotective effects, whereas genetic abrogation of TRPV1 results in increased myocardial damage after ischemia and reperfusion injury in comparison to wild-type mice. Furthermore, blood pressure changes have been noted upon TRPV1 stimulation. Similarly, the TRPV2 channel has also been associated with changes in blood pressure and cardiac function depending on how and where the channel is activated. Interestingly, overexpression of TRPV2 channels in the heart induces dystrophic cardiomyopathy; however, stimulation under physiologic conditions leads to improved cardiac function. Probenecid, a TRPV2 agonist, has been studied as a model therapy for its inotropic effects and potential use in the treatment of cardiomyopathy. In this review, we present an up to date account of the growing evidence that supports the study of TRPV1 and TRPV2 channels as targets for therapeutic agents of cardiovascular diseases.

Invasive sinonasal actinomycosis: case report and literature review.

Actinomycosis is a rare anaerobic bacterial infection typically caused by Actinomyces israelii. Although part of normal flora in the oral cavity, and respiratory and digestive tracts, A israelii can give rise to pathologic infections most commonly reported in the oral cavity from odontogenic causes. We present a rare case of invasive actinomycosis presenting with extensive midface destruction involving the maxilla and paranasal sinuses, with mucosal necrosis mimicking an aggressive neoplasm. The diagnosis is usually reached only after histopathologic analysis showing characteristic sulfur granules with filamentous gram-positive, non-acid-fast bacteria. We review the literature on its epidemiology, clinical presentation, diagnosis, treatment, and prognosis.

[The clinical picture of gout is changing]. / Kihdin muuttuva kuva.

The prevalence of gout in the western countries is 1-2%. The disease has become more common during the last two decades, and the same time its clinical picture has changed. The disease is often polyarticular, the patients are older than before and they have more often associated cardiovascular diseases and renal insufficiency. Effective treatment of acute gout is nonsteroidal anti-inflammatory drugs with intra-articular or systematic corticosteroids. The goal for the treatment of intermittent and chronic gout is to maintain serum urate concentration velow 360 micromol/l by diet and by antihyperuricemic meditation, primarly allopurinole and probenecid. Febuxostat is a new xanthine oxidase inhibitor, which will be available for the treatment of refractory gout in the near future. Special attention should be paid on detecting and treating cardiovascular diseases and their risk factors in patients with gout.

[Observation on therapeutic effect of electroacupuncture plus blood-letting puncture and cupping combined with diet intervention for treatment of acute gouty arthritis].

OBJECTIVE: To explore a more effective therapy for acute gouty arthritis. METHODS: Sixty cases were randomly divided into an observation group and a control group, 30 cases in eachgroup. On the basis of diet intervention, the observation group was treated with electroacupuncture at local points combined with blood-letting puncture and cupping, and the control group with oral administration of Probenecid. Their therapeutic effects were ob served. RESULTS: The effective rate was 96.7% in the observation group which was better than 86.7% in the control group (P < 0.01). After treatment, blood uric acid decreased significantly in the two groups (both P < 0.01), the observed group being lower than the control group (P < 0.01). CONCLUSION: On the basis of diet intervention, electroacupuncture plus blood-letting puncture and cupping is a better therapy for acute gouty arthritis.

Effect of nifedipine on tubular handling of uric acid in transplanted kidney on cyclosporine A treatment.

Hyperuricemia resulting from tubular urate transport defects is a well-known nephrotoxic effect of cyclosporine A (CyA) on renal blood perfusion in organ recipients. The aim of this study was to define the mechanism of the tubular urate transport defect in hyperuricemic renal graft recipients on CyA and to evaluate the effect of nifedipine retard administration on this tubular dysfunction. Tubular uric acid transport was evaluated by the probenecid test in 17 hyperuricemic (group 1) and 6 normouricemic (group 2) renal graft recipients treated with CyA. Maximal urate excretion after probenecid administration was 25.5 +/- 4.6 versus 42.5 +/- 7.7% (p < 0.001) and postsecretory urate reabsorption was 79.2 +/- 8.3 versus 78.5 +/- 9.7% (NS), respectively. The effects of nifedipine retard on renal urate transport were evaluated in 6 hyperuricemic patients. Seven days of nifedipine therapy did not significantly decrease mean serum uric acid levels (7.7 +/- 1.6 to 7.1 +/- 1.1 mg/dl) nor increase urate clearance (3.8 +/- 1.3 to 4.7 +/- 1.6 ml/min/1.73 m2). The uricosuric effect of probenecid was manifested by an increase in tubular urate transport from 25.5 +/- 4.6 to 37.3 +/- 7.2%, p < 0.01, paralleled by an increase in postsecretory urate reabsorption from 20.5 +/- 3.7 to 31.4 +/- 5.7% (p < 0.003). Postsecretory reabsorption expressed as a percentage of secreted urate in both evaluations did not differ significantly (80.3 +/- 6.2 vs. 84.4 +/- 3.1%).(ABSTRACT TRUNCATED AT 250 WORDS)

An open study of procaine penicillin G, clavulanate-potentiated amoxycillin and probenecid in the treatment of acute gonorrhoea.

In an open study 55 patients presenting with acute gonorrhoea were given 4.8 mega units procaine penicillin G, intramuscularly, and oral probenecid (1 g) plus one 375-mg tablet clavulanate-potentiated amoxycillin orally. Before this treatment, 53 patients (96.4%) had presented with a purulent discharge, and dysuria was present in 47 patients (85.5%). The presence of Neisseria gonorrhoeae was confirmed by bacterial culture in 54 patients (98.2%). The majority of pathogens (92.5%) were penicillin resistant. On day 3 after treatment, dysuria was absent in 53 patients (96.4%) and there was no discharge in 40 cases (72.7%). N. gonorrhoeae was eradicated in 53 patients (96.4%). Two further patients were bacteriologically cured, but were suffering from post-gonococcal urethritis. The patients in whom discharge was still apparent were further assessed on day 7; discharge was resolved or resolving in all but one patient. There was one treatment failure. No adverse reactions were reported.

Temporal trends in gonococcal antibiotic resistance in Baltimore.

Each month from August 1986 through July 1990, clinical and laboratory data were evaluated for the first 25 urethral isolates of Neisseria gonorrhoeae from men attending a Baltimore sexually transmitted disease (STD) clinic as part of an effort to understand factors that contribute to changes in gonococcal antimicrobial susceptibility. During the 48-month study period, 1193 gonococcal isolates were evaluated; the proportion of penicillinase-producing N. gonorrhoeae (PPNG) isolates steadily increased, the prevalence of tetracycline-resistant N. gonorrhoeae (TRNG) remained relatively stable, and chromosomally mediated penicillin resistance increased steadily during the first 5 6-month intervals, then decreased, only to increase again during the final 2 6-month intervals. Changes in antibiotic treatment regimens for gonorrhea were associated with changes in the prevalence of chromosomally mediated penicillin resistance. In a supplementary study to characterize patterns of antibiotic use among men and women attending the STD clinics, 9% of patients reported antibiotic use in the 2 weeks prior to clinic visit. Antibiotics were taken prior to clinic attendance by 65% of patients reporting antibiotic use, because of concerns regarding possible STD or STD exposure. These patients were significantly less likely to be culture positive for N. gonorrhoeae when compared with patients who did not report antibiotic use. Temporal trends in N. gonorrhoeae antibiotic resistance appear to be influenced by many factors, including treatment regimens and self medication.

Penicillin resistant Neisseria gonorrhoeae in low prevalence areas: implications for cost-effective management.

Though ampicillin is no longer recommended as first-line therapy for infections caused by Neisseria gonorrhoeae, the cost and efficacy of this policy in low prevalence areas has not been investigated. The problem was highlighted by an outbreak of penicillin-resistant N. gonorrhoeae in an area where the proportion of resistance had previously been only 0.14%. A decision analysis was performed to determine the cost-effectiveness of beta-lactamase screening and alternative therapies for patients attending sexually transmitted diseases clinics. Empiric therapy with an inexpensive agent active against resistant strains, such as ciprofloxacin, was the most cost-effective approach and remained more cost-effective than alternative strategies whenever the proportion of resistant isolates exceeded 3%. Ceftriaxone was less cost-effective. In low prevalence areas, and in areas where the return rate of recalled patients is high, ampicillin therapy was cost-effective, but beta-lactamase screening should be performed routinely.

The ocular manifestations of syphilis in the human immunodeficiency virus type 1-infected host.

Nine patients with active ocular or optic nerve involvement by syphilis who also had concurrent human immunodeficiency virus type-1 (HIV-1) infection are described. The ocular manifestations of syphilis led to the discovery of HIV-1 seropositivity in four of nine cases. Fifteen eyes were affected. Ocular manifestations were: iridocyclitis in three eyes, vitreitis in one eye, retinitis or neuroretinitis in five eyes, papillitis in two eyes, optic perineuritis in two eyes, and retrobulbar optic neuritis in two eyes. Three patients diagnosed with acquired immune deficiency syndrome (AIDS) had the worst initial visual acuities. Six of nine patients had evidence of concomitant central nervous syndrome (CNS) involvement with syphilis. Benzathine penicillin was administered intramuscularly to three patients. All three had relapses. Seven of nine patients treated intravenously with high-dose penicillin had dramatic responses to therapy with improvement in vision and serologies and no evidence of relapse. Regimens accepted for the treatment of neurosyphilis appear to be adequate for the treatment of ocular syphilis in HIV-1-infected patients though further long-term follow-up will be required.

Multicenter randomized study of single-dose ofloxacin versus amoxicillin-probenecid for treatment of uncomplicated gonococcal infection.

The safety and efficacy of ofloxacin, 400 mg orally, were compared with those of amoxicillin, 3.0 g, plus probenecid, 1.0 g orally, as single-dose therapy in 201 heterosexual patients (101 men and 100 women) with uncomplicated gonococcal infection. Treatment groups were comparable in age, duration of symptoms, number of sexual partners within the previous month, and number of previous episodes of sexually transmitted diseases. The cure rate for men treated with ofloxacin was 98% (47 of 48), and that for women was 100% (52 of 52). Cure rates for both men and women treated with amoxicillin-probenecid were 96% (51 of 53 men; 46 of 48 women). All 13 patients with positive rectal cultures and 7 of 8 patients with positive pharyngeal cultures treated with ofloxacin were cured. Neither regimen reliably eradicated coexistent infection with Chlamydia trachomatis. The MIC of ofloxacin for all but two of 198 pretreatment isolates was 0.3 microgram/ml or less. The MIC of amoxicillin for 90% of isolates tested was 1.0 microgram/ml. Single oral doses of ofloxacin and of amoxicillin plus probenecid were equally effective for treatment of urethral and cervical gonorrhea. Ofloxacin appears promising as treatment for rectal and pharyngeal infection, but studies with larger numbers of patients with rectal or pharyngeal infection or both are required for confirmation. Relative contraindications in children and possibly pregnant women plus the potential for single-step, high-level resistance may limit the usefulness of quinolone therapy for gonorrhea.

A comparative study of aztreonam and procaine penicillin/probenecid in the treatment of uncomplicated gonorrhoea.

236 patients with uncomplicated gonorrhoea were randomly allocated to receive either aztreonam or procaine penicillin plus probenecid. 115 patients (50 men and 65 women) with uncomplicated gonorrhoea were treated with 1 g aztreonam as a single intramuscular injection. The success rate among those who attended at least one follow up examination after treatment was 99%. The antibiotic was well tolerated and there were no side effects. The observed minimum inhibitory concentrations (MICs) of aztreonam in vitro were very much lower than obtainable serum concentrations. The penicillin treated patients who were evaluable showed a failure rate of 12.8%. We conclude that aztreonam is effective against Neisseria gonorrhoeae, including penicillinase-producing strains, both in vivo and in vitro.

Single dose piperacillin in treating uncomplicated gonococcal urethritis in men.

A single intramuscular dose of piperacillin 2 g, with probenecid 1 g orally, was used to treat 82 men with uncomplicated gonococcal urethritis due to penicillinase producing strains of Neisseria gonorrhoeae (PPNG) or non-PPNG. All 49 patients infected with non-PPNG strains were cured, as opposed to only 25 (76%) of 33 patients infected with PPNG strains, giving an overall success rate of 90%. No serious side effects of treatment were observed. Post gonococcal urethritis (PGU) occurred in 18% of the patients treated. Antibiotic susceptibility tests showed that 44 (96%) of the 46 non-PPNG strains tested had MICs of piperacillin of 2 mg/l or less and 26 (76%) of the 34 PPNG strains had MICs of 32 mg/l or more. This regimen is not recommended for use as first line treatment in areas where there is a high incidence of infection with PPNG strains. It is, however, highly effective against non-PPNG strains.