Positive relation between dopamine neuron degeneration and metabolic connectivity disruption in the MPTP plus probenecid mouse model of Parkinson's disease

The clinical manifestation of Parkinson's disease (PD) appears when neurodegeneration is already advanced, compromising the efficacy of disease-modifying treatment approaches. Biomarkers to identify the early stages of PD are therefore of paramount importance for the advancement of the therapy of PD. In the present study, by using a mouse model of PD obtained by subchronic treatment with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and the clearance inhibitor probenecid (MPTPp), we identified prodromal markers of PD by combining in vivo positron emission tomography (PET) imaging and ex vivo immunohistochemistry. Longitudinal PET imaging of the dopamine transporter (DAT) by [18F]-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane ([18F]-FP-CIT), and brain glucose metabolism by 2-deoxy-2-[18F]-fluoroglucose ([18F]-FDG) were performed before MPTPp treatment and after 1, 3, and 10 MPTPp administrations, in order to assess relation between dopamine neuron integrity and brain connectivity. The results show that in vivo [18F]-FP-CIT in the dorsal striatum was not modified after the first administration of MPTPp, tended to decrease after 3 administrations, and significantly decreased after 10 MPTPp administrations. Post-mortem immunohistochemical analyses of DAT and tyrosine hydroxylase (TH) in the striatum showed a positive correlation with [18F]-FP-CIT, confirming the validity of repeated MPTPp-treated mice as a model that can reproduce the progressive pathological changes in the early phases of PD. Analysis of [18F]-FDG uptake in several brain areas connected to the striatum showed that metabolic connectivity was progressively disrupted, starting from the first MPTPp administration, and that significant connections between cortical and subcortical regions were lost after 10 MPTPp administrations, suggesting an association between dopamine neuron degeneration and connectivity disruption in this PD model. The results of this study provide a relevant model, where new drugs that can alleviate neurodegeneration in PD could be evaluated preclinically.

L-Carnitine augments probenecid anti-inflammatory effect in monoiodoacetate-induced knee osteoarthritis in rats: involvement of miRNA-373/P2X7/NLRP3/NF-κB milieu

Osteoarthritis (OA) is a degenerative joint disease, whereas the underlying molecular trails involved in its pathogenesis are not fully elucidated. Hence, the current study aimed to investigate the role of miRNA-373/P2X7/NLRP3/NF-κB trajectory in its pathogenesis as well as the possible anti-inflammatory effects of probenecid and l-carnitine in ameliorating osteoarthritis via modulating this pathway. In the current study, male Sprague Dawley rats were used and monoiodoacetate (MIA)-induced knee osteoarthritis model was adopted. Probenecid and/or L-carnitine treatments for 14 days succeeded in reducing OA knee size and reestablishing motor coordination and joint mobility assessed by rotarod testing. Moreover, different treatments suppressed the elevated serum levels of IL-1β, IL-18, IL-6, and TNF-α via tackling the miRNA-373/P2X7/NLRP3/NF-κB, witnessed as reductions in protein expressions of P2X7, NLRP3, cleaved caspase-1 and NF-κB. These were accompanied by increases in procaspase-1 and IκB protein expression and in miRNA-373 gene expression OA knee to various extents. In addition, different regimens reversed the abnormalities observed in the H and E as well as Safranin O-Fast green OA knees stained sections. Probenecid or l-carnitine solely showed comparable results on the aforementioned parameters, whereas the combination therapy had the most prominent effect on ameliorating the aforementioned parameters. In conclusion, l-carnitine augmented the probenecid's anti-inflammatory effect to attenuate MIA-induced osteoarthritis in rats by provoking the miRNA-373 level and inhibiting the P2X7/NLRP3/NF-κB milieu, leading to the suppression of serum inflammatory cytokines: IL-1β, IL-18, IL-6, and TNF-α. These findings suggest the possibility of using probenecid and l-carnitine as a useful therapeutic option for treatment of osteoarthritis.

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.

Antiviral Activity of Probenecid and Oseltamivir on Influenza Virus Replication

Influenza can cause respiratory infections, leading to significant morbidity and mortality in humans. While current influenza vaccines offer varying levels of protection, there remains a pressing need for effective antiviral drugs to supplement vaccine efforts. Currently, the FDA-approved antiviral drugs for influenza include oseltamivir, zanamivir, peramivir, and baloxavir marboxil. These antivirals primarily target the virus, making them vulnerable to drug resistance. In this study, we evaluated the efficacy of the neuraminidase inhibitor, oseltamivir, against probenecid, which targets the host cells and is less likely to engender resistance. Our results show that probenecid has superior antiviral efficacy compared to oseltamivir in both in vitro replication assays and in vivo mouse models of influenza infection.

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 slows disease progression in a murine model of autosomal dominant polycystic kidney disease

Development of autosomal dominant polycystic kidney disease (ADPKD) involves renal epithelial cell abnormalities. Cystic fluid contains a high level of ATP that, among other effects, leads to a reduced reabsorption of electrolytes in cyst-lining cells, and thus results in cystic fluid accumulation. Earlier, we demonstrated that Pkd1RC/RC mice, a hypomorphic model of ADPKD, exhibit increased expression of pannexin-1, a membrane channel capable of ATP release. In the current study, we found that human ADPKD cystic epithelia have higher pannexin-1 abundance than normal collecting ducts. We hypothesized that inhibition of pannexin-1 function with probenecid can be used to attenuate ADPKD development. Renal function in male and female Pkd1RC/RC and control mice was monitored between 9 and 20 months of age. To test the therapeutic effects of probenecid (a uricosuric agent and a pannexin-1 blocker), osmotic minipumps were implanted in male and female Pkd1RC/RC mice, and probenecid or vehicle was administered for 42 days until 1 year of age. Probenecid treatment improved glomerular filtration rates and slowed renal cyst formation in male mice (as shown in histopathology). The mechanistic effects of probenecid on sodium reabsorption and fluid transport were tested on polarized mpkCCDcl4 cells subjected to short-circuit current measurements, and in 3D cysts grown in Matrigel. In the mpkCCDcl4 epithelial cell line, probenecid elicited higher ENaC currents and attenuated in vitro cyst formation, indicating lower sodium and less fluid retention in the cysts. Our studies open new avenues of research into targeting pannexin-1 in ADPKD pathology.

Probenecid Inhibits Respiratory Syncytial Virus (RSV) Replication

RNA viruses like SARS-CoV-2, influenza virus, and respiratory syncytial virus (RSV) are dependent on host genes for replication. We investigated if probenecid, an FDA-approved and safe urate-lowering drug that inhibits organic anion transporters (OATs) has prophylactic or therapeutic efficacy to inhibit RSV replication in three epithelial cell lines used in RSV studies, i.e., Vero E6 cells, HEp-2 cells, and in primary normal human bronchoepithelial (NHBE) cells, and in BALB/c mice. The studies showed that nanomolar concentrations of all probenecid regimens prevent RSV strain A and B replication in vitro and RSV strain A in vivo, representing a potential prophylactic and chemotherapeutic for RSV.

Therapeutic Strategies for the Treatment of Chronic Hyperuricemia: An Evidence-Based Update

This article aims to critically review the evidence on the available therapeutic strategies for the treatment of hyperuricemia. For this reason, several papers were reviewed. Xanthine oxidase inhibitors are the safest and most effective uric acid lowering drugs for the management of chronic hyperuricemia, while the efficacy of uricosuric agents is strongly modulated by pharmacogenetics. Emergent drugs (lesinurad, peglotidase) were found to be more effective for the acute management of refractory hyperuricemia, but their use is supported by a relatively small number of clinical trials so that further well-designed clinical research is needed to deepen their efficacy and safety profile.

Probenecid Improves Cardiac Function in Subjects with a Fontan Circulation and Augments Cardiomyocyte Calcium Homeostasis

Subjects with functionally univentricular circulation who have completed staged single ventricle palliation, with the final stage culminating in the Fontan procedure, are often living into adulthood. However, high morbidity and mortality remain prevalent in these patients, as diastolic and systolic dysfunction of the single systemic ventricle are linked to Fontan circulatory failure. We presently investigated the effects of probenecid in post-Fontan patients. Used for decades for the treatment of gout, probenecid has been shown in recent years to positively influence cardiac function via effects on the Transient Receptor Potential Vanilloid 2 (TRPV2) channel in cardiomyocytes. Indeed, we observed that probenecid improved cardiac function and exercise performance in patients with a functionally univentricular circulation. This was consistent with our findings from a retrospective cohort of patients with single ventricle physiology where TRPV2 expression was increased. Experiments in isolated cardiomyocytes associated these positive actions to augmentation of diastolic calcium homeostasis.

Cost-effectiveness of sequential urate lowering therapies for the management of gout in Singapore

Aims: Allopurinol is the most common urate lowering therapy (ULT) used to treat gout but may cause life-threatening severe cutaneous adverse reactions (SCAR) in a small number of patients. Risk of SCAR is increased for patients with the HLA-B*58:01 genotype. When alternative ULT is required, febuxostat or probenecid are recommended. The aim of this study was to conduct a cost-utility analysis of sequential ULT treatment strategies for gout, including strategies with and without HLA-B*58:01 genotyping prior to treatment initiation, with a view to inform optimal gout management in Singapore.Materials and methods: A Markov model was developed from the Singapore healthcare payer perspective. Reflecting local practice, 12 different treatment strategies containing at least one ULT (allopurinol, febuxostat, probenecid) were evaluated in adults with gout. Response rates (SUA < 6mg/dL) were derived from an in-house network meta-analysis and from published literature. Incremental cost-effectiveness ratios (ICERs) were calculated over a 30-year time horizon, with costs and benefits discounted at 3% per annum. Sensitivity analyses were conducted to explore uncertainties.Results: Sequential treatment of allopurinol 300 mg/day-allopurinol 600 mg/day-probenecid ("standard of care") was cost-effective compared to no ULT, with an ICER of SGD1,584/QALY. Allopurinol300-allopurinol600-probenecid-febuxostat sequence compared to allopurinol300-allopurinol600-probenecid had an ICER of SGD11,400/QALY. All other treatment strategies were dominated by preceding strategies. Treatment strategies incorporating HLA-B*58:01 genotyping before ULT use were dominated by the corresponding non-genotyping strategy.Conclusions: Current standard of care (allopurinol300-allopurinol 600-probenecid) for gout is cost-effective compared with no ULT in the local context. Febuxostat is unlikely to be cost-effective in Singapore at current prices unless it is used last-line.

Preventing Calpain Externalization by Reducing ABCA1 Activity with Probenecid Limits Melanoma Angiogenesis and Development

Calpains, intracellular proteases specifically inhibited by calpastatin, play a major role in neoangiogenesis involved in tumor invasiveness and metastasis. They are partly exteriorized via the ATP-binding cassette transporter A1(ABCA1) transporter, but the importance of this process in tumor growth is still unknown. The aim of our study was to investigate the role of extracellular calpains in a model of melanoma by blocking their extracellular activity or exteriorization. In the first approach, a B16-F10 model of melanoma was developed in transgenic mice expressing high extracellular levels of calpastatin. In these mice, tumor growth was inhibited by ∼ 3-fold compared with wild-type animals. In vitro cytotoxicity assays and in vivo tumor studies have demonstrated that this protection was associated with a defect in tumor neoangiogenesis. Similarly, in wild-type animals given probenecid to blunt ABCA1 activity, melanoma tumor growth was inhibited by ∼ 3-fold. Again, this response was associated with a defect in neoangiogenesis. In vitro studies confirmed that probenecid limited endothelial cell migration and capillary formation from vascular explants. The observed reduction in fibronectin cleavage under these conditions is potentially involved in the response. Collectively, these studies demonstrate that probenecid, by blunting ABCA1 activity and thereby calpain exteriorization, limits melanoma tumor neoangiogenesis and invasiveness.

Gout - An update of aetiology, genetics, co-morbidities and management

Gout is an increasingly common chronic disorder of urate crystal deposition that manifests as flares of acute inflammatory arthritis. Hyperuricaemia is a prerequisite and a fifth of both men and woman are hyperuricaemic. The prevalence of gout is much lower than the prevalence of hyperuricaemia for reasons that are not currently clear. Gout is more common in men than women prior to menopause due to the uricosuric effects of oestrogen, but after menopause the incidence of gout rises substantially in women. Co-morbidities are an important issue in gout, with cardiovascular disease, diabetes mellitus, obesity and chronic kidney disease all common in patients with gout. Environmental factors like diet affect the incidence of gout but there is little evidence to support an emphasis on diet in treating established gout. The diagnosis of gout is often made without the use of joint aspiration and validated diagnostic rules are available for both primary and secondary care as well as classification criteria for research use. The overarching principle of the management of gout with pharmacotherapy is the need to reduce serum urate levels to below a target of 0.30 mmol/L or 0.36 mmol/L depending on whether it is tophaceous or non-tophaceous respectively. The use of allopurinol has been researched extensively and newer strategies for safer effective dosing are now recommended. Newer agents have been introduced for the treatment of gout, including febuxostat and lesinurad. A number of important questions in the field are under current investigation.

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.

Antibiotics for treating gonorrhoea in pregnancy

BACKGROUND

Gonorrhoea is a sexually transmitted infection that is caused by Neisseria gonorrhoeae, and is a major public health challenge today. N gonorrhoeae can be transmitted from the mother's genital tract to the newborn during birth, and can cause gonococcal ophthalmia neonatorum as well as systemic neonatal infections. It can also cause endometritis and pelvic sepsis in the mother. This review updates and replaces an earlier Cochrane Review on antibiotics for treating this infectious condition.

OBJECTIVES

To assess the clinical effectiveness and harms of antibiotics for treating gonorrhoea in pregnant women.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2017), LILACS database (1982 to April 5, 2017), the WHO International Clinical Trials Registry Platform (ICTRP; April 5, 2017), ClinicalTrials.gov (April 5, 2017), the ISRCTN Registry (April 5, 2017), and Epistemonikos (April 5, 2017). We also searched reference lists of all retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing the use of antibiotics for treating gonorrhoea in pregnancy. The antibiotics could have been used alone or in combination, were administered parenterally, orally, or both, and were compared with another antibiotic.We included RCTs regardless of their publication status (published, unpublished, published as an article, an abstract, or a letter), language, or country. We applied no limits on the length of follow-up.We excluded RCTs using a cluster- or cross-over design, or quasi-RCTs.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked them for accuracy.

MAIN RESULTS

We included two RCTs, that randomised 514 pregnant women (347 women analysed) at a mean gestational age of 22 weeks. Both trials were conducted in the outpatient department of the same two hospitals in the USA between 1993 and 2001, and had a follow-up of 14 days. One of the trials was sponsored by a drug company. We considered both trials to be at a high risk of bias.One trial compared ceftriaxone (125 mg, intramuscular) with cefixime (400 mg, oral); the other trial had three arms, and assessed ceftriaxone (250 mg, intramuscular) versus either amoxicillin (3 g, oral) plus probenecid (1 g, oral) or spectinomycin (2 g, intramuscular). We did not include the spectinomycin data because this medication is no longer produced. We were unable to conduct meta-analysis because the trials compared different medications.We found inconclusive evidence that there were clear differences in the cure of gonococcal infections (genital, extragenital, or both) between intramuscular ceftriaxone versus oral amoxicillin plus oral probenecid (risk ratio (RR) 1.07, 95% confidence interval (CI) 0.98 to 1.16; one RCT; 168 women; very low-quality evidence) or intramuscular ceftriaxone versus oral cefixime (RR 0.99, 95% CI 0.91 to 1.08; one RCT; 95 women; very low-quality evidence).Neither of the trials reported on two of this review's primary maternal outcomes: incidence of obstetric complications (miscarriage, premature rupture of membranes, preterm delivery, or fetal death), or disseminated gonococcal infection, or on the incidence of neonatorum ophthalmia in the neonates.One trial reported one case of vomiting in the oral amoxacillin plus probenecid group. Trials reported pain at the injection sites, but did not quantify it. Hyperberbilurrubinemia was more frequent in neonates whose mothers were exposed to ceftriaxone. There were no clear differences between groups for neonatal malformation.

AUTHORS' CONCLUSIONS

This Cochrane Review found high levels of cure of gonococcal infections in pregnancy with the given antibiotic regimens. However, the evidence in this review is inconclusive as it does not support one particular regimen over another. This conclusion was based on very low-quality evidence (downgraded for poor trial design, imprecision) from two trials (involving 514 women), which we assessed to be at a high risk of bias for a number of domains. The harm profiles of the antibiotic regimes featured in this review remain unknown.High-quality RCTs are needed, with sufficient power to assess the clinical effectiveness and potential harms of antibiotics in pregnant women with gonorrhoea. These should be planned according to Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT),conducted following CONSORT recommendations, and based on Patient-Centered Outcomes Research Institute (PCORI) outcomes.

Effect of Uric Acid Lowering on Renin-Angiotensin-System Activation and Ambulatory BP: A Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Higher serum uric acid levels, even within the reference range, are strongly associated with increased activity of the renin-angiotensin system (RAS) and risk of incident hypertension. However, the effect of lowering serum uric acid on RAS activity in humans is unknown, although the data that lowering serum uric acid can reduce BP are conflicting.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a double-blind placebo-controlled trial conducted from 2011 to 2015, we randomly assigned 149 overweight or obese adults with serum uric acid ≥5.0 mg/dl to uric acid lowering with either probenecid or allopurinol, or to placebo. The primary endpoints were kidney-specific and systemic RAS activity. Secondary endpoints included mean 24-hour systolic BP, mean awake and asleep BP, and nocturnal dipping.

RESULTS

Allopurinol and probenecid markedly lowered serum uric acid after 4 and 8 weeks compared with placebo (mean serum uric acid in allopurinol, probenecid, and placebo at 8 weeks was 2.9, 3.5, and 5.6 mg/dl, respectively). The change in kidney-specific RAS activity, measured as change in the median (interquartile range) renal plasma flow response to captopril (in ml/min per 1.73 m2) from baseline to 8 weeks, was -4 (-25 to 32) in the probenecid group (P=0.83), -4 (-16 to 9) in the allopurinol group (P=0.32), and 1 (-21 to 17) in the placebo group (P=0.96), with no significant treatment effect (P=0.77). Similarly, plasma renin activity and plasma angiotensin II levels did not significantly change with treatment. The change in mean (±SD) 24-hour systolic BPs from baseline to 8 weeks was -1.6±10.1 with probenecid (P=0.43), -0.4±6.1 with allopurinol (P=0.76), and 0.5±6.0 with placebo (P=0.65); there was no significant treatment effect (P=0.58). Adverse events occurred in 9%, 12%, and 2% of those given probenecid, allopurinol, or placebo, respectively.

CONCLUSIONS

In contrast to animal experiments and observational studies, this randomized, placebo-controlled trial found that uric acid lowering had no effect on kidney-specific or systemic RAS activity after 8 weeks or on mean systolic BP. These data do not support the hypothesis that higher levels of uric acid are a reversible risk factor for increased BP.

Uricosuric medications for chronic gout

BACKGROUND

Uricosuric agents have long been used in the treatment of gout but there is little evidence regarding their benefit and safety in this condition.

OBJECTIVES

To assess the benefits and harms of uricosuric medications in the treatment of chronic gout.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 4, 2013), Ovid MEDLINE and Ovid EMBASE for studies to the 13 May 2013. We also searched the World Health Organization Clinical Trials Registry, ClinicalTrials.gov and the 2011 to 2012 American College of Rheumatology and European League against Rheumatism abstracts. WE considered black box warnings and searched drug safety databases to identify and describe rare adverse events.

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) or quasi-randomised controlled trials (controlled clinical trials (CCTs)) that compared uricosuric medications (benzbromarone, probenecid or sulphinpyrazone) alone or in combination with another therapy (placebo or other active uric acid-lowering medication, or non-pharmacological treatment) in adults with chronic gout for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies for inclusion, extracted data and performed a risk of bias assessment. Main outcomes were frequency of acute gout attacks, serum urate normalisation, study participant withdrawal due to adverse events, total adverse events, pain reduction, function and tophus regression.

MAIN RESULTS

The search identified four RCTs and one CCT that evaluated the benefit and safety of uricosurics for gout. One study (65 participants) compared benzbromarone with allopurinol for a duration of four months; one compared benzbromarone with allopurinol (36 participants) for a duration of nine to 24 months; one study (62 participants) compared benzbromarone with probenecid for two months and one study (74 participants) compared benzbromarone with probenecid. One study (37 participants) compared allopurinol with probenecid. No study was completely free from bias.Low-quality evidence from one study (55 participants) comparing benzbromarone with allopurinol indicated uncertain effects in terms of frequency of acute gout attacks (4% with benzbromarone versus 0% with allopurinol; risk ratio (RR) 3.58, 95% confidence interval (CI) 0.15 to 84.13), while moderate-quality evidence from two studies (101 participants; treated for four to nine months) indicated similar proportions of participants achieving serum urate normalisation (73.9% with benzbromarone versus 60% with allopurinol; pooled RR 1.27, 95% CI 0.90 to 1.79). Low-quality evidence indicated uncertain differences in withdrawals due to adverse events (7.1% with benzbromarone versus 6.1% with allopurinol; pooled RR 1.25, 95% CI 0.28 to 5.62), and total adverse events (20% with benzbromarone versus 6.7% with allopurinol; RR 3.00, 95% CI 0.64 to 14.16). The study did not measure pain reduction, function and tophus regression.When comparing benzbromarone with probenecid, there was moderate-quality evidence based on one study (62 participants) that participants taking benzbromarone were more likely to achieve serum urate normalisation after two months (81.5% with benzbromarone versus 57.1% with probenecid; RR 1.43, 95% CI 1.02 to 2.00). This indicated that when compared with probenecid, five participants needed to be treated with benzbromarone in order to have one additional person achieve serum urate normalisation (number needed to treat for an additional beneficial outcome (NNTB) 5). However, the second study reported no difference in the absolute decrease in serum urate between these groups after 12 weeks. Low-quality evidence from two studies (129 participants) indicated uncertain differences between treatments in the frequency of acute gout attacks (6.3% with benzbromarone versus 10.6% with probenecid; pooled RR 0.73, 95% CI 0.09 to 5.83); fewer withdrawals due to adverse events with benzbromarone (2% with benzbromarone versus 17% with probenecid; pooled RR 0.15, 95% CI 0.03 to 0.79, NNTB 7) and fewer total adverse events (21% with benzbromarone versus 47% with probenecid; pooled RR 0.43, 95% CI 0.25 to 0.74; NNTB 4). The studies did not measure pain reduction, function and tophus regression.Low-quality evidence based on one small CCT (37 participants) indicated uncertainty around the difference in the incidence of acute gout attacks between probenecid and allopurinol after 18 to 20 months' treatment (53% with probenecid versus 55% with allopurinol; RR 0.96, 95% CI 0.53 to 1.75). The study did not measure or report the proportion achieving serum urate normalisation, pain reduction, function, tophus regression, withdrawal due to adverse events and total adverse events.

AUTHORS' CONCLUSIONS

There was moderate-quality evidence that there is probably no important difference between benzbromarone and allopurinol at achieving serum urate normalisation, but that benzbromarone is probably more successful than probenecid at achieving serum urate normalisation in people with gout. There is some uncertainty around the effect estimates, based on low-quality evidence from only one or two trials, on the number of acute gout attacks, the number of withdrawals due to adverse events or the total number of participants experiencing adverse events when comparing benzbromarone with allopurinol. However, when compared with probenecid, benzbromarone resulted in fewer withdrawals due to adverse events and fewer participants experiencing adverse events. Low-quality evidence from one small study indicated uncertain effects in the incidence of acute gout attacks when comparing probenecid with allopurinol therapy. We downgraded the evidence because of a possible risk of performance and other biases and imprecision.

Pannexin 1: a novel participant in neuropathic pain signaling in the rat spinal cord

Pannexin 1 (panx1) is a large-pore membrane channel expressed in many tissues of mammals, including neurons and glial cells. Panx1 channels are highly permeable to calcium and adenosine triphosphatase (ATP); on the other hand, they can be opened by ATP and glutamate, two crucial molecules for acute and chronic pain signaling in the spinal cord dorsal horn, thus suggesting that panx1 could be a key component for the generation of central sensitization during persistent pain. In this study, we examined the effect of three panx1 blockers, namely, 10panx peptide, carbenoxolone, and probenecid, on C-reflex wind-up activity and mechanical nociceptive behavior in a spared nerve injury neuropathic rat model involving sural nerve transection. In addition, the expression of panx1 protein in the dorsal horn of the ipsilateral lumbar spinal cord was measured in sural nerve-transected and sham-operated control rats. Sural nerve transection resulted in a lower threshold for C-reflex activation by electric stimulation of the injured hindpaw, together with persistent mechanical hypersensitivity to pressure stimuli applied to the paw. Intrathecal administration of the panx1 blockers significantly depressed the spinal C-reflex wind-up activity in both neuropathic and sham control rats, and decreased mechanical hyperalgesia in neuropathic rats without affecting the nociceptive threshold in sham animals. Western blotting showed that panx1 was similarly expressed in the dorsal horn of lumbar spinal cord from neuropathic and sham rats. The present results constitute the first evidence that panx1 channels play a significant role in the mechanisms underlying central sensitization in neuropathic pain.

Pharmacological treatment in calcinosis cutis associated with connective-tissue diseases

BACKGROUND

Dystrophic calcinosis cutis is a common manifestation in connective tissue diseases, but there's still no consensus on treatment.

OBJECTIVES

The purpose of this review is to discuss the current pharmacological options of treatment in calcinosis cutis related to rheumatic diseases.

METHOD

We performed an extensive MEDLINE search of articles from 1970 to January 2014 using the index word "calcinosis" and the co-indexing terms "treatment", "calcium channel blocker", "diltiazem", "nifedipine", "verapamil", "amlodipine", "anticoagulant", "warfarin", "bisphosphonate", "etidronate", "pamidronate", "alendronate", "risedronate", "aluminum hydroxide", "probenecid", "antibiotic", "tetracycline", "minocycline", "ceftriaxone", "colchicine", "intravenous immunoglobulin", "sodium thiosulfate", "TNF-alpha inhibitors", "infliximab", "rituximab", "thalidomide", "corticosteroids", "stem cell transplantation".

RESULTS

Diltiazem is recommended by some authors as first-line approach in calcinosis cutis and is also the therapeutic principal referred by the largest number of available publications. It seems to be efficient in more than half of the reported cases. There remain, however, a significant number of patients in which another solution must be found. The general trends observed over time are of switching the search of solutions in dystrophic calcinosis cutis related to connective tissue diseases, from therapies on calcium metabolism to therapies for the underlying disease. The new options available in the management of calcinosis cutis, like biological therapies or intravenous immunoglobulin, seem to be promising, but not universally successful. In children with severe forms, hematopoietic stem cell transplantation can also be taken into consideration.

CONCLUSIONS

Data for all therapies proposed in calcinosis cutis is generally reported in single cases and small case series and so, the existent data is all yielding a low level of evidence.

The history and future of probenecid

Probenecid was initially developed with the goal of reducing the renal excretion of antibiotics, specifically penicillin. It is still used for its uricosuric properties in the treatment in gout, but its clinical relevance has sharply fallen and is rarely used today for either. Interestingly, throughout the last 60 years, there have been a host of apparently unrelated studies using probenecid in the clinical and basic research arena, including its potential use in the diagnosis and treatment of depression and its use to prevent fura-2 leakage in calcium transient studies. Recently, it has been shown that it is also an agonist of the Transient Receptor Potential Vanilloid 2 channel. Due to its unique action and new findings implicating TRPV channels in physiology and in disease, probenecid may have a new future as a research tool, and perhaps as a clinical agent in the neurology and cardiology fields. We review the history of probenecid in this paper and its potential future uses.

[The clinical picture of gout is changing]

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.

Efficacy and tolerability of urate-lowering drugs in gout: a randomised controlled trial of benzbromarone versus probenecid after failure of allopurinol

OBJECTIVES

To investigate the efficacy and tolerability of allopurinol as the first-choice antihyperuricaemic treatment for gout, and compare the efficacy and tolerability of benzbromarone and probenecid as second-choice treatment.

METHODS

Prospective, multicentre, open-label, two-stage randomised controlled trial in gout patients with normal renal function. Enrolled patients were given 300 mg allopurinol for 2 months (stage 1). Those patients who could not tolerate allopurinol or who did not attain the target serum urate concentration (sUr) < or=0.30 mmol/l (5.0 mg/dl), which was defined as successful, were randomised to benzbromarone 200 mg/day or probenecid 2 g/day for another 2 months (stage 2).

RESULTS

96 patients were enrolled in stage 1. 82 patients (85%) were eligible for the analysis at the end of stage 1: there was a mean (SD) decrease in sUr concentration of 35 (11)% from baseline; 20 patients (24%) attained target sUr < or=0.30 mmol/l; and 9 patients (11%) stopped allopurinol because of adverse drug reactions. 62 patients were enrolled in stage 2. 27 patients received benzbromarone (3 patients not eligible for analysis) and 35 received probenecid (4 patients not eligible for analysis). Treatment with benzbromarone was successful in 22/24 patients (92%) and with probenecid in 20/31 patients (65%) (p = 0.03 compared with benzbromarone). Compared with baseline values, there was a mean (SD) decrease of sUr concentration of 64 (9)% with benzbromarone and 50 (7)% with probenecid (p<0.001).

CONCLUSION

This study showed that allopurinol 300 mg/day has a poor efficacy and tolerability profile when used to attain a biochemical predefined target level of sUr < or =0.30 mmol/l, following 2 months of treatment. In stage 2, benzbromarone 200 mg/day was more effective and better tolerated than probenecid 2 g/day.

Biochemical effectiveness of allopurinol and allopurinol-probenecid in previously benzbromarone-treated gout patients

In 2003, the uricosuric drug benzbromarone was withdrawn from the market. The first alternative drug of choice was the xanthine oxidase inhibitor allopurinol. The purpose was to (1) investigate the efficacy of allopurinol (standard dosage) compared with previous treatment with benzbromarone; and (2) investigate the combination therapy allopurinol-probenecid as an effective alternative treatment compared with previous benzbromarone treatment. A prospective, open study was carried out in a cohort of 51 gout patients who discontinued benzbromarone therapy because of market withdrawal. Patients were given 200-300 mg allopurinol (stage 1). When allopurinol failed to attain the target serum urate (sUr) levels Collapse

Key Words Collapse

MESH Headings

• Allopurinol/adverse effects
• Allopurinol/therapeutic use
• Benzbromarone/therapeutic use
• Dose-Response Relationship, Drug
• Drug Therapy, Combination
• Female
• Gout/drug therapy
• Humans
• Hyperuricemia/drug therapy
• Male
• Middle Aged
• Probenecid/therapeutic use
• Uric Acid/blood
• Uric Acid/urine
• Uricosuric Agents/adverse effects
• Uricosuric Agents/therapeutic use

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Grants Collapse

Affiliation(s)

Mattheus K Reinders Department of Clinical Pharmacy and Pharmacology, Medical Centre Leeuwarden, Henri Dunantweg 2, 8934 AD, Leeuwarden, The Netherlands.
Eric N van Roon
Pieternella M Houtman
Jacobus R B J Brouwers
Tim L Th A Jansen

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Uric acid lowering therapy: prescribing patterns in a large cohort of older adults

BACKGROUND

Uric acid lowering therapy (UALT) is considered a chronic treatment for gout. Relatively little is known about adherence to UALT.

METHODS

We assessed adherence with UALT over a 1-year study period among 9823 older adults enrolled in a pharmacy benefit program. Two adherence measures were calculated, the percentage of days covered (PDC) and the time until an extended break (at least 60 days) in treatment. A PDC <80% was considered poor adherence and its predictors were examined in multivariable logistic models.

RESULTS

The mean (SD) PDC was 54% (36%) with 64% of patients considered poorly compliant over the study period. A total of 56% had experienced an extended break in UALT. Predictors of poor adherence included younger age (odds ratio (OR) 1.50, 95% CI 1.33-1.69 for ages 65-74 compared with 85 and above) and African-American race (OR 1.86, 95% CI 1.52-2.27 compared with Caucasian race). Most patients (93%) received their initial UALT prescription from a non-specialist and this also predicted poor adherence (OR 1.15, 95% CI 0.96-1.38 compared with rheumatologists or nephrologists).

CONCLUSION

Adherence with UALT is poor. While uric acid levels were not measured in this study, poor adherence with UALT is likely to reduce attainment of goal uric acid levels.

Prevention of electrical stimulation-induced increase of c-fos immunoreaction in the caudal trigeminal nucleus by kynurenine combined with probenecid

The systemic administration of nitroglycerine, regarded as a migraine model, was previously observed to result in an increased number of c-fos immunoreactive secondary sensory neurons in the caudal trigeminal nucleus, which forward nociceptive impulses to the thalamus. The present investigation tested the hypothesis of whether kynurenine in combination with systemically administered probenecid protects second-order trigeminal neurons against stimulation arriving via central processes of trigeminal ganglion cells. Electrical stimulation of the trigeminal ganglion, one of the experimental migraine models, is known to induce an increase in the number of c-fos immunoreactive second-order nerve cells projecting to the thalamus. Since the synapses between first- and second-order trigeminal neurons are presumed to be mediated by excitatory amino acids, postsynaptic NMDA receptors should be inhibited by kynurenic acid, an endogenous NMDA receptor antagonist. Kynurenic acid, however, does not cross the blood-brain barrier, and its use as a neuroprotective agent is therefore not feasible. In contrast, kynurenine, from which kynurenic acid is formed on the action of kynurenine aminotransferase, passes the blood-brain barrier without difficulty. After the i.p. injection of kynurenine combined with probenecid it was found that the stimulation-induced increase in the c-fos immunoreactivity of the secondary sensory neurons does not occur.

Efficacy of probenecid for a patient with juvenile dermatomyositis complicated with calcinosis

Calcinosis of juvenile dermatomyositis (JDM) is a crucial problem because it is refractory to various therapies. An 11-year-old boy who had been treated for JDM with interstitial pneumonia developed calcinosis of both legs despite treatment with corticosteroid and cyclosporin A. Images of his knees showed massive calcinosis with restricted range of motion. Probenecid was used to reduce calcinosis, resulting in remarkable improvement of calcinosis accompanied by normalization of serum phosphorus level and disability after 17 months of administration. We suggest that probenecid is useful for the treatment of calcinosis of JDM.

An update on the treatment options for gout and calcium pyrophosphate deposition

Gout and calcium pyrophosphate deposition disease are two common causes of inflammatory joint disease. Despite differences underlying their pathogenesis, their clinical presentation and treatment share some common features. Optimal treatment for both requires prompt resolution of acute synovitis, reduction of chronic joint damage and management of associated conditions. Available therapeutic interventions and future strategies are reviewed in this article.

Hyperuricaemia and preeclampsia: is there a pathogenic link?

OBJECTIVE

A hypothesis, based on animal studies and human observational studies, was developed proposing a direct pathogenic link between hyperuricemia and preeclampsia. Epidemiological characteristics of preeclampsia such as its uniqueness to humans and an increased incidence of preeclampsia in multiple pregnancies, increased body mass index, renal and hypertensive disease all have uric acid as their common denominator. Animal studies have linked hyperuricaemia to hypertensive, cardiovascular and renal disease. The aim of the study was to determine whether lowering the serum uric acid levels in preeclampsia would affect biochemical parameters and hypertensive control.

DESIGN

A randomized, double-blind, placebo controlled study.

SETTING

A tertiary referral center.

POPULATION

Forty women with preeclampsia between 26 and 32 weeks gestation.

INTERVENTION

Probenecid 250 mg twice daily for seven days.

MAIN OUTCOME MEASURES

Renal function and haematological parameters, hypertensive control.

RESULTS

In the Probenecid group, there was a significant drop in the serum uric acid levels. Lower uric acid levels in the Probenecid group had no significant effect on blood pressure. Patients in the Probenecid group had a significantly lower serum creatinine value at the end of the study when compared to patients in the placebo group. Other renal function parameters (creatinine clearance, urea, 24 h urinary protein excretion) did not show any significant difference between the two groups. Platelet count differed between the two groups with the platelet count being significantly higher in the Probenecid group at the end of the study.

CONCLUSION

The significant improvement in the platelet count in the Probenecid group warrants further study.

Pharmacology of drugs for hyperuricemia. Mechanisms, kinetics and interactions

The pharmacological profile of drugs for hyperuricemia is reviewed. These agents may reduce the amount of uric acid in blood by means of two different ways: (1) by reducing uric acid production through the inhibition of the enzyme xanthine oxidase (as allopurinol); (2) by increasing uric acid clearance through an inhibition of its renal tubular reabsorption (as probenecid), or through its metabolic conversion to a more soluble compound (as urate oxidase). Allopurinol is rapidly converted in the body to the active metabolite oxypurinol whose total body exposure may be 20-fold greater than that of the parent compound due to a much longer elimination half-life. Allopurinol undergoes several pharmacokinetic interactions with concomitant administered drugs, some of which may be potentially hazardous (especially with mercaptopurine and azathioprine). Probenecid is an uricosuric agent which undergoes extensive hepatic metabolism and whose elimination after high doses may become dose dependent. It may inhibit renal tubular secretion of several coadministered agents, including methotrexate and sulphonylureas. Rasburicase is a recombinant form of the enzyme urate oxidase which catalyzes the conversion of uric acid to the more soluble compound allantoin. Unlike allopurinol, it does not promote accumulation of hypoxanthine and xanthine in plasma, thus preventing the risk of xanthine nephropathy. Rasburicase showed no significant accumulation in children after administration of either 0.15 or 0.20 mg/kg/daily for 5 days. Rasburicase probably undergoes peptide hydrolysis and in in vitro studies was shown neither to inhibit or induce cytochrome P450 isoenzymes nor to interact with several drugs, so that no relevant interaction is expected during cotreatment in patients.

Potential utility of natural polyphenols for reversing fat-induced insulin resistance

There is intriguing recent evidence that the beta subunit of the signalsome--IKKbeta, a crucial catalyst of NF-kappaB activation--is an obligate mediator of the disruption of insulin signaling induced by excessive exposure of tissues to free fatty acids and by hypertrophy of adipocytes. Thus, agents which safely inhibit or suppress the activation of IKKbeta may have utility for reversing insulin resistance syndrome and aiding control of type 2 diabetes. Two natural agents which can achieve this effect in vitro--and which may have clinical potential in this regard--are the polyphenols resveratrol and silibinin. To date, limited absorbability and/or rapid glucuronidation have prevented these agents from achieving full therapeutic utility, but, by administering these agents in optimally absorbable forms, and co-administering inhibitors of glucuronidation such as probenecid, it may prove feasible to make these agents more clinically viable. Oral silibinin, in the guise of the milk thistle extract silymarin, already has documented clinical utility in a range of hepatic disorders, and recent evidence that dietary silibinin can inhibit the growth of certain cancers in rodents suggests that this agent may indeed have clinical potential as an IKKbeta inhibitor. A report that silymarin has a favorable impact on glycemic and lipidemic control in type 2 diabetics with cirrhosis, may or may not be indicative of IKKbeta inhibition in skeletal muscle and adipocytes. In light of the fact that IKKbeta plays a crucial role, not only in the induction of insulin resistance, but also atherogenesis, a host of inflammatory disorders, and the survival and spread of cancer, the development of pharmaceutical agents that could safely and feasibly achieve a down-regulation of IKKbeta activity would have broad therapeutic and preventive implications.

Therapeutic potential of folate uptake inhibition in Plasmodium falciparum

Plasmodium falciparum parasites resistant to the combination sulfadoxine-pyrimethamine are spreading in Africa, particularly in East Africa. This is a matter of concern because there are no other affordable drugs available. This article provides the evidence indicating that sulfadoxine-pyrimethamine resistance can be reversed in vitro and discusses how this information might be exploited to extend the therapeutic lifetime of sulfadoxine-pyrimethamine in vivo.

Once-Daily Cefazolin and Probenecid for Skin and Soft Tissue Infections

OBJECTIVE

To review the pharmacokinetic and clinical evidence for the use of once-daily cefazolin and probenecid in the treatment of skin and soft tissue infections (SSTI).

DATA SOURCES

MEDLINE (1966–July 2003), EMBASE (1980–July 2003), and PubMed (1966–July 2003) databases for English language, human reports were searched. Search terms included cefazolin, probenecid, cellulitis, and soft tissue infections.

STUDY SELECTION AND DATA EXTRACTION

Studies that described pharmacokinetic and clinical outcomes that evaluated the use of cefazolin in conjunction with probenecid for SSTI were included. All studies were evaluated independently by both authors. For pharmacokinetic studies, the effect of probenecid on the pharmacokinetics of cefazolin was evaluated. For clinical trials, efficacy and safety endpoints were evaluated. For efficacy endpoints, definition of cure was used as defined by each trial.

DATA SYNTHESIS

In all 3 pharmacokinetic studies identified, the addition of probenecid to cefazolin therapy prolonged the half-life and increased serum concentrations of cefazolin. This process allowed serum concentrations to be above the minimal inhibitory concentrations (MIC) for the most likely skin pathogens ( Staphylococcus aureus, β-hemolytic streptococci) at the end of the dosing interval. In the first of 2 clinical trials, 7 (7%) of 96 patients receiving intravenous ceftriaxone 2 g and oral probenecid 1 g daily were reported to fail therapy compared with 8 (8%) of 98 patients receiving intravenous cefazolin 2 g and oral probenecid 1 g daily. In the second clinical trial, clinical success was reported in 51 (86%) of 59 patients receiving the same doses of cefazolin and probenecid as above compared with 55 (96%) of 57 patients receiving intravenous ceftriaxone 1 g and oral placebo daily.

CONCLUSIONS

Limited pharmacokinetic and clinical data suggest that intravenous cefazolin 2 g and oral probenecid 1 g daily is an effective regimen in the treatment of SSTI.

Successful use of intralesional and intravenous cidofovir in association with indole-3-carbinol in an 8-year-old girl with pulmonary papillomatosis

We report the history of an 8-year-old girl who was treated for suspected lung lesions of respiratory papillomatosis with Indole-3-Carbinol, local and intravenous injections of Cidofovir for 27 months. This is the first report where a complete cure of the lung lesions occurred in a child, and was sustained for at least 24 months.

Conjugated bilirubin induces multidrug resistance-associated protein 2 mRNA expression and in vivo cisplatin resistance in rat hepatoma AH66 cells

In vivo cisplatin resistance of rat ascites hepatoma AH66 cells is suggested to result from the induction of multidrug resistance-associated protein 2 (MRP2) expression by ascites fluid (ASF) in the peritoneal cavity. The in vitro cisplatin sensitivity of AH66 cells grown in assay medium containing 5% fetal bovine serum in Dulbecco's modified Eagle's medium (5% FBS DMEM) did not change when the cells were treated with probenecid, an inhibitor of anion transporters, while the decreased cisplatin sensitivity of AH66 cells cultured in an assay medium containing 5% ASF (5% ASF DMEM) was restored by probenecid. Furthermore, in an in vivo study, the survival span (%ILS) of AH66-bearing rats was markedly extended by combination therapy with cisplatin and probenecid, compared with either agent alone. The expression of MRP2 mRNA was increased when AH66 cells were cultured in medium containing 5% ASF or 5% bile for 24 h. The induction of MRP2 mRNA expression in AH66 cells was also observed in the presence of heat-denatured ASF. The bilirubin content in ASF was characteristically higher than that in FBS, normal rat serum or AH66-bearing rat serum. Unconjugated bilirubin did not change the expression of MRP2 mRNA, whereas conjugated bilirubin markedly increased it. The cisplatin uptake in AH66 cells after culture in 5% FBS DMEM containing conjugated bilirubin was about half that of the cells cultured in 5% FBS DMEM alone (p < 0.01). In addition, the cisplatin sensitivity of the cells was significantly lowered by the addition of conjugated bilirubin. The expression of MRP2 mRNA in rat normal hepatocytes was also increased after culture in medium containing 5% ASF or 5% bile. These results indicated that conjugated bilirubin, a component of ASF, induces the mRNA expression of MRP2, which is a determinant of the in vivo cisplatin resistance of AH66 cells.

Endometritis does not predict reproductive morbidity after pelvic inflammatory disease

OBJECTIVE

We investigated the association between endometritis and reproductive morbidity.

STUDY DESIGN

Participants were 614 women in the PID Evaluation and Clinical Health (PEACH) Study with pelvic pain, pelvic organ tenderness, and leukorrhea, mucopurulent cervicitis, or untreated cervicitis. We compared women with endometritis (>or=5 neutrophils or >or=2 plasma cells), Neisseria gonorrhoeae or Chlamydia trachomatis upper genital tract infection (UGTI) or both to women without endometritis/UGTI for outcomes of pregnancy, infertility, recurrent pelvic inflammatory disease (PID), and chronic pelvic pain (CPP), adjusting for age, race, education, PID history, and baseline infertility.

RESULTS

Endometritis/UGTI was not associated with reduced pregnancy (odds ratio [OR] 0.8, 95% CI 0.6-1.2) or elevated infertility (OR 1.0, 95% CI 0.6-1.6), recurrent PID (OR 0.6, 95% CI 0.4-0.9), or CPP (OR 0.6, 95% CI 0.4-0.9). PEACH participants with and without endometritis/UGTI had higher age- and race-specific pregnancy rates than 1997 national rates.

CONCLUSION

Among women with clinically suspected mild-to-moderate PID treated with standard antibiotics, endometritis/UGTI was not associated with reproductive morbidity.

Pharmacokinetics and renal effects of cidofovir with a reduced dose of probenecid in HIV-infected patients with cytomegalovirus retinitis

To reduce possible nephrotoxicity, intravenous prehydration with normal saline and administration of probenecid must be used with each infusing of the antiviral cidofovir. The recommended standard-dose probenecid (SDP) regimen is 2 g at 3 hours before cidofovir, then 1 g at 2 and 8 hours after cidofovir (total 4 g). A new regimen of reduced-dose probenecid (RDP), 2 g at 1 hour before cidofovir without additional probenecid administrations after infusion (total 2 g), was compared with SDP using a randomized, open-label, parallel design. A single dose of cidofovir (5 mg/kg) was given as a 1-hour infusion after saline prehydration to 24 HIV-infected patients (11 males, 13 females) with cytomegalovirus retinitis and good renal function. Blood was sampled for 48 hours and urine for 24 hours after the start of the cidofovir infusion. Cidofovir pharmacokinetics did not differ significantly between groups. Average key pharmacokinetic parameters (Cmax, tmax, lambda z, AUC0-infinity, Vss, CL, CLR, fe, ER) for RDP differed by less than 17% from SDP and were consistent with previously reported SDP data. Renal function parameters, other safety endpoints, and adverse events were similar between the groups. Therefore, the reduced-dose regimen of probenecid provided renal protection after a single dose of cidofovir and did not alter the pharmacokinetics of cidofovir in patients with moderately good renal function. Although the overall pharmacokinetic results do not show a significant difference in cidofovir exposure with the new probenecid regimen, the main issue of safety of the new dose regimen, both relating to renal toxicity and probenecid-related adverse events, is not adequately addressed in a small study.