Acyclovir nephrotoxicity: a case report highlighting the importance of prevention, detection, and treatment of acyclovir-induced nephropathy

Development and characterization of formulations based on combinatorial potential of antivirals against genital herpes

Herpes simplex virus type 2 (HSV-2) treatment faces challenges due to antiviral resistance and systemic side effects of oral therapies. Local delivery of antiviral agents, such as tenofovir (TDF) and zinc acetate dihydrate (ZAD), may offer improved efficacy and reduced systemic toxicity. This study's objective is to develop and evaluate local unit dose formulations of TDF and ZAD combination for local treatment of HSV-2 infection and exploring their individual and combinatory effects in vitro. The study involved the development of immediate-release film and pessary formulations containing TDF and ZAD. These formulations were characterized for physicochemical properties and in vitro drug release profiles. Cytotoxicity and antiviral activity assays were conducted to evaluate the individual and combinatory effects of TDF and ZAD. Film formulations released over 90% of the drugs within 1 h, and pessary formulations within 90 min, ensuring effective local drug delivery. ZAD showed moderate antiviral activity while TDF exhibited significant antiviral activity at non-cytotoxic concentrations. The combination of TDF and ZAD demonstrated synergistic effects in co-infection treatments, reducing the concentration required for 50% inhibition of HSV-2. Developed film and pessary formulations offer consistent and predictable local drug delivery, enhancing antiviral efficacy while minimizing systemic side effects. The combination of TDF and ZAD showed potential synergy against HSV-2, particularly in co-infection treatments. Further preclinical studies on pharmacokinetics, safety, and efficacy are necessary to advance these formulations toward clinical application.

The immunobiology of corneal HSV-1 infection and herpetic stromal keratitis

SUMMARYHuman alphaherpesvirus 1 (HSV-1) is a highly successful neurotropic pathogen that primarily infects the epithelial cells lining the orofacial mucosa. After primary lytic replication in the oral, ocular, and nasal mucosal epithelial cells, HSV-1 establishes life-long latency in neurons within the trigeminal ganglion. Patients with compromised immune systems experience frequent reactivation of HSV-1 from latency, leading to virus entry in the sensory neurons, followed by anterograde transport and lytic replication at the innervated mucosal epithelial surface. Although recurrent infection of the corneal mucosal surface is rare, it can result in a chronic immuno-inflammatory condition called herpetic stromal keratitis (HSK). HSK leads to gradual vision loss and can cause permanent blindness in severe untreated cases. Currently, there is no cure or successful vaccine to prevent latent or recurrent HSV-1 infections, posing a significant clinical challenge to managing HSK and preventing vision loss. The conventional clinical management of HSK primarily relies on anti-virals to suppress HSV-1 replication, anti-inflammatory drugs (such as corticosteroids) to provide symptomatic relief from pain and inflammation, and surgical interventions in more severe cases to replace damaged cornea. However, each clinical treatment strategy has limitations, such as local and systemic drug toxicities and the emergence of anti-viral-resistant HSV-1 strains. In this review, we summarize the factors and immune cells involved in HSK pathogenesis and highlight alternate therapeutic strategies for successful clinical management of HSK. We also discuss the therapeutic potential of immunoregulatory cytokines and immunometabolism modulators as promising HSK therapies against emerging anti-viral-resistant HSV-1 strains.

A decreasing plasma concentration of a toxicologically active metabolite 9-carboxymethoxymethylguanine after dialysis - A potential new clinical biomarker for improving encephalopathy in patients treated with acyclovir

Although acyclovir is a key drug for the treatment of herpes infections, a consciousness disorder known as "acyclovir encephalopathy" is among its side effects. We encountered a patient with encephalopathy and measured the plasma and cerebrospinal fluid concentrations of acyclovir and its toxicologically active metabolite 9-carboxymethoxymethylguanine (CMMG). Before dialysis, cerebrospinal fluid concentrations of acyclovir and CMMG in this patient with a consciousness disorder were approximately 10% and 1%, respectively, of their plasma concentrations. After 3 days of dialysis, plasma CMMG levels decreased to detectable but below quantitative levels (<0.1 μg/mL), resulting in normal consciousness. These results suggest that decreasing plasma CMMG concentration could be one of clinical biomarkers for improving consciousness in patients with encephalopathy associated with acyclovir.

Role of Innate Interferon Responses at the Ocular Surface in Herpes Simplex Virus-1-Induced Herpetic Stromal Keratitis

Herpes simplex virus type 1 (HSV-1) is a highly successful pathogen that primarily infects epithelial cells of the orofacial mucosa. After initial lytic replication, HSV-1 enters sensory neurons and undergoes lifelong latency in the trigeminal ganglion (TG). Reactivation from latency occurs throughout the host's life and is more common in people with a compromised immune system. HSV-1 causes various diseases depending on the site of lytic HSV-1 replication. These include herpes labialis, herpetic stromal keratitis (HSK), meningitis, and herpes simplex encephalitis (HSE). HSK is an immunopathological condition and is usually the consequence of HSV-1 reactivation, anterograde transport to the corneal surface, lytic replication in the epithelial cells, and activation of the host's innate and adaptive immune responses in the cornea. HSV-1 is recognized by cell surface, endosomal, and cytoplasmic pattern recognition receptors (PRRs) and activates innate immune responses that include interferons (IFNs), chemokine and cytokine production, as well as the recruitment of inflammatory cells to the site of replication. In the cornea, HSV-1 replication promotes type I (IFN-α/β) and type III (IFN-λ) IFN production. This review summarizes our current understanding of HSV-1 recognition by PRRs and innate IFN-mediated antiviral immunity during HSV-1 infection of the cornea. We also discuss the immunopathogenesis of HSK, current HSK therapeutics and challenges, proposed experimental approaches, and benefits of promoting local IFN-λ responses.

A phase 3, randomized, double-blind, placebo-controlled study evaluating a single, patient-initiated dose of amenamevir for recurrent herpes labialis

Amenamevir (ASP2151), a novel, non-nucleoside analog, antiviral drug, inhibits the enzyme activities of helicase and primase, which are essential for replication of herpes viral genomic DNA. In this phase 3, randomized, double-blind, placebo-controlled, multicenter study, the authors investigated the efficacy and safety of a single patient-initiated dose of amenamevir to treat recurrent herpes labialis. Adult immunocompetent patients with recurrent herpes labialis who had the experience and ability to recognize prodromal symptoms were randomly assigned to administer amenamevir 1200 mg or placebo as a patient-initiated therapy within 6 hours after onset of prodromal symptoms. The primary efficacy end point was time to healing of all herpes labialis lesions in the modified intention-to-treat population. Secondary efficacy end points were time to crusting of all herpes labialis lesions, time to resolution of pain accompanying herpes labialis, proportion of patients with aborted lesions, and time to resolution of subjective symptoms accompanying herpes labialis. The modified intention-to-treat population, which excluded patients with aborted lesions, comprised 298 patients who self-initiated amenamevir and 307 who took placebo. Amenamevir demonstrated superiority over placebo for the primary end point; the median time to all lesion healing was 5.1 days for amenamevir versus 5.5 days for placebo (hazard ratio, 1.24; 95% confidence interval, 1.06-1.46; p = 0.0085). Time to crusting of all lesions was significantly shorter with amenamevir versus placebo (p = 0.0065); there were no significant between-group differences in other secondary outcomes. Treatment-emergent adverse events in both groups were generally mild in severity; there were two moderate events that were judged unrelated to study treatment, and no severe or serious events. In summary, a single patient-initiated dose of amenamevir 1200 mg taken within 6 hours of prodromal symptom onset significantly shortened the time to all lesion healing of recurrent herpes labialis compared with placebo, with no clinically important safety concerns.

Optimizing Antiviral Dosing for HSV and CMV Treatment in Immunocompromised Patients

Herpes simplex virus (HSV) and cytomegalovirus (CMV) are DNA viruses that are common among humans. Severely immunocompromised patients are at increased risk of developing HSV or CMV disease due to a weakened immune system. Antiviral therapy can be challenging because these drugs have a narrow therapeutic window and show significant pharmacokinetic variability. Above that, immunocompromised patients have various comorbidities like impaired renal function and are exposed to polypharmacy. This scoping review discusses the current pharmacokinetic (PK) and pharmacodynamic (PD) knowledge of antiviral drugs for HSV and CMV treatment in immunocompromised patients. HSV and CMV treatment guidelines are discussed, and multiple treatment interventions are proposed: early detection of drug resistance; optimization of dose to target concentration by therapeutic drug monitoring (TDM) of nucleoside analogs; the introduction of new antiviral drugs; alternation between compounds with different toxicity profiles; and combinations of synergistic antiviral drugs. This research will also serve as guidance for future research, which should focus on prospective evaluation of the benefit of each of these interventions in randomized controlled trials.

Subphenotypes of acute kidney injury in children

PURPOSE OF REVIEW

The purpose of this review is to describe acute kidney injury (AKI) phenotypes in children.

RECENT FINDINGS

AKI is a heterogenous disease that imposes significant morbidity and mortality on critically ill and noncritically ill patients across the age spectrum. As our understanding of AKI and its association with outcomes has improved, it is becoming increasingly apparent that there are distinct AKI subphenotypes that vary by cause or associated conditions. We have also learned that severity, duration, and repeated episodes of AKI impact outcomes, and that integration of novel urinary biomarkers of tubular injury can also reveal unique subphenotypes of AKI that may not be otherwise readily apparent.

SUMMARY

Studies that further delineate these unique AKI subphenotypes are needed to better understand the impact of AKI in children. Further delineation of these phenotypes has both prognostic and therapeutic implications.

Liposomal siRNA Formulations for the Treatment of Herpes Simplex Virus-1: In Vitro Characterization of Physicochemical Properties and Activity, and In Vivo Biodistribution and Toxicity Studies

Herpes simplex virus-1 (HSV-1) is highly contagious, and there is a need for a therapeutic means to eradicate it. We have identified an siRNA (siHSV) that knocks down gene expression of the infected cell protein 0 (ICP0), which is important in the regulation of HSV infection. The selected siHSV was encapsulated in liposomes to overcome its poor stability, increase cell permeability, and prolonging siRNA circulation time. Several siRNAs against ICP0 have been designed and identified. We examined the role of various parameters, including formulation technique, lipids composition, and ratio. An optimal liposomal siHSV formulation (LipDOPE-siHSV) was characterized with desirable physiochemical properties, in terms of nano-size, low polydispersity index (PDI), neutral surface charge, high siHSV loading, spherical shape, high stability in physiologic conditions in vitro, and long-term shelf-life stability (>1 year, 4 °C). The liposomes exhibited profound internalization by human keratinocytes, no cytotoxicity in cell cultures, no detrimental effect on mice liver enzymes, and a gradual endo-lysosomal escape. Mice biodistribution studies in intact mice revealed accumulation, mainly in visceral organs but also in the trigeminal ganglion. The therapeutic potential of siHSV liposomes was demonstrated by significant antiviral activity both in the plaque reduction assay and in the 3D epidermis model, and the mechanism of action was validated by the reduction of ICP0 expression levels.

Insuficiencia renal aguda secundaria al tratamiento con Aciclovir por herpes zoster en pacientes con lupus eritematoso sistémico: reporte de dos casos

Se presentan dos casos de pacientes con lupus eritematoso sistémico con recidiva de herpes zoster, que desarrollan insuficiencia renal aguda secundaria al tratamiento con Aciclovir endovenoso.Descripción del plan de cuidados: el plan de cuidados estuvo abocado a tratar las necesidades alteradas según la clasificación de Virginia Henderson. Estas necesidades alteradas fueron: la necesidad de eliminación, higiene e integridad de la piel, dolor y movilización. Para el proceso de atención de enfermería se aplicó la taxonomía NANDA.Evaluación del plan: Tras aplicar el proceso de atención de enfermería se logró mejorar la función renal, recuperar la integridad cutánea, se evitó infecciones por las lesiones en la piel producidas por el herpes zoster, se controló el dolor, y se mejoró la movilidad del brazo izquierdo de una de las pacientes que padecía paresia.Conclusiones: es menester para enfermería realizar un seguimiento minucioso de los pacientes que presentan tratamiento con Aciclovir, especialmente de aquellos que presentan patologías crónicas de base, como lupus eritematoso sistémico en recidivas con herpes zoster, para prevenir eventos adversos asociados al fármaco

Evaluation of Adverse Drug Reactions in Paediatric Patients: A Retrospective Study in Turkish Hospital

Drug safety in paediatric patients is a serious public health concern around the world. The paediatric patients are more prone to adverse drug reactions (ADRs) than adults. Moreover, there is a scarcity of information about ADRs in paediatric patients. This study was conducted to determine the frequency, causality, severity, preventability of paediatric patients’ ADRs reported in a tertiary care hospital in Adana, Turkey. A retrospective study was conducted on all spontaneously reported ADRs between January 01, 2020, to July 30, 2021, in paediatric patients. The ADRs reports were evaluated in terms of gender, age, ADR characteristics, suspected drugs and reporting source. All included ADRs reports were characterized according to the Naranjo Algorithm/World Health Organization (WHO) causality scales, Hartwig/Siegel and Common Terminology Criteria for Adverse Events (CTCAE) severity scales, the modified Schoumock and Thornton preventability scale and hospital pharmacovigilance center criteria for seriousness. Therapeutic groups were also coded using the WHO-Anatomical Therapeutic and Chemical (ATC) classification. During the study period, 8,912 paediatric patients who were admitted had 16 ADRs with 1.7 ADRs/1,000 admissions. The majority of ADRs were found in infants (31.2%) and children (56.2%) as compared to adolescents (12.5%). ADRs were observed more in females (81.2%) than males. Skin (62.5%) was the most affected organ due to the ADRs, and maculopapular rash and erythema multiforme were the most commonly reported symptoms. Most ADRs were probable/likely (93.7%), severe (50%), preventable or probably preventable (43.7%) and serious (37.5%). Antibiotics (93.7%) were found to be the most common cause of ADRs in paediatric patients. The majority of ADRs were associated with vancomycin (68.7%). Most of the ADRs were reported by a medical doctor in this study. This small sample size study highlights significant problems of ADRs in paediatric patients, mainly caused by antibiotics and with a majority of ADRs manifest as skin reactions. Furthermore, a high proportion of the identified ADRs were found to be preventable. More focused efforts are needed at the national level to avoid preventable ADRs in hospitals. Monitoring and management of ADRs and future studies would be beneficial for better patient care and safety.

Nano Drug Delivery Platforms for Dental Application: Infection Control and TMJ Management-A Review

The oral cavity is an intricate environment subjected to various chemical, physical, and thermal injuries. The effectiveness of the local and systemically administered drugs is limited mainly due to their toxicities and poor oral bioavailability that leads to the limited effectiveness of the drugs in the target tissues. To address these issues, nanoparticle drug delivery systems based on metals, liposomes, polymeric particles, and core shells have been developed in recent years. Nano drug delivery systems have applications in the treatment of patients suffering from temporomandibular joint disorders such as preventing degeneration of cartilage in patients suffering from rheumatoid arthritis and osteoarthritis and alleviating the pain along with it. The antibacterial dental applications of nano-drug delivery systems such as silver and copper-based nanoparticles include these agents used to arrest dental caries, multiple steps in root canal treatment, and patients suffering from periodontitis. Nanoparticles have been used in adjunct with antifungals to treat oral fungal infections such as candida albicans in denture wearers. Acyclovir being the most commonly used antiviral has been used in combination with nanoparticles against an array of viral infections such as the herpes simplex virus. Nanoparticles based combination agents offer more favorable drug release in a controlled manner along with efficient delivery at the site of action. This review presents an updated overview of the recently developed nanoparticles delivery systems for the management of temporomandibular joint disorders along with the treatment of different oral infections.

Advancing Our Understanding of Corneal Herpes Simplex Virus-1 Immune Evasion Mechanisms and Future Therapeutics

Herpes stromal keratitis (HSK) is a disease that commonly affects the cornea and external eye and is caused by Herpes Simplex Virus type 1 (HSV-1). This virus infects approximately 66% of people worldwide; however, only a small portion of these people will develop symptoms in their lifetime. There is no cure or vaccine available for HSV-1; however, there are treatments available that aim to control the inflammation caused by the virus and prevent its recurrence. While these treatments are beneficial to those suffering with HSK, there is a need for more effective treatments to minimise the need for topical steroids, which can have harmful effects, and to prevent bouts of disease reactivation, which can lead to progressive corneal scarring and visual impairment. This review details the current understanding of HSV-1 infection and discusses potential novel treatment options including microRNAs, TLRs, mAbs, and aptamers.

Pathobiology and treatment of viral keratitis

Keratitis is one of the most prevalent ocular diseases manifested by partial or total loss of vision. Amongst infectious (viz., microbes including bacteria, fungi, amebae, and viruses) and non-infectious (viz., eye trauma, chemical exposure, and ultraviolet exposure, contact lens) risk factors, viral keratitis has been demonstrated as one of the leading causes of corneal opacity. While many viruses have been shown to cause keratitis (such as rhabdoviruses, coxsackieviruses, etc.), herpesviruses are the predominant etiologic agent of viral keratitis. This chapter will summarize current knowledge on the prevalence, diagnosis, and pathobiology of viral keratitis. Virus-mediated immunomodulation of host innate and adaptive immune components is critical for viral persistence, and dysfunctional immune responses may cause destruction of ocular tissues leading to keratitis. Immunosuppressed or immunocompromised individuals may display recurring disease with pronounced severity. Early diagnosis of viral keratitis is beneficial for disease management and response to treatment. Finally, we have discussed current and emerging therapies to treat viral keratitis.

Infection-Induced Porcine Ex Vivo Corneal Wound Model to Study the Efficacy of Herpes Simplex Virus-1 Entry and Replication Inhibitors

Corneal infections by viruses and bacteria can result in ocular surface defects, ulcers, or wounds. Herpes simplex virus type-1 (HSV-1) is a human virus with global seroprevalence in the range of 60-90%. While the virus more commonly causes mucocutaneous lesions including ulcers on the face and mouth, it is also a leading cause of infection-associated blindness. In this chapter, we discuss an in-depth protocol required to evaluate corneal damage due to HSV-1 infection using porcine models of ex vivo infection. Our methods can be adapted to study similar infections caused by other viruses and bacteria.

Standalone or combinatorial phenylbutyrate therapy shows excellent antiviral activity and mimics CREB3 silencing

Herpesviruses are ubiquitous human pathogens that tightly regulate many cellular pathways including the unfolded protein response to endoplasmic reticulum (ER) stress. Pharmacological modulation of this pathway results in the inhibition of viral replication. In this study, we tested 4-phenylbutyrate (PBA), a chemical chaperone-based potent alleviator of ER stress, for its effects on herpes simplex virus (HSV) type 1 infection. Through in vitro studies, we observed that application of PBA to HSV-infected cells results in the down-regulation of a proviral, ER-localized host protein CREB3 and a resultant inhibition of viral protein synthesis. PBA treatment caused viral inhibition in cultured human corneas and human skin grafts as well as murine models of ocular and genital HSV infection. Thus, we propose that this drug can provide an alternative to current antivirals to treat both ocular HSV-1 and genital HSV-2 infections and may be a strong candidate for human trials.

Antiviral Agents for the Prevention and Treatment of Herpes Simplex Virus Type-1 Infection in Clinical Oncology: A Network Meta-Analysis

Cancer therapy may be complicated and compromised by viral infections, including oral herpes simplex virus (HSV) infection. This network meta-analysis aimed to identify the best antiviral agent to prevent or treat oral HSV infection in patients being treated for cancer. A search was conducted for trials published since inception until the 10th of May 2020 in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials. A network meta-analysis was performed on the data from randomized controlled trials that assessed antiviral agents for preventive or therapeutic activity vs. placebo, no treatment or any other active intervention in patients being treated for cancer. The agents were ranked according to their effectiveness in the prevention of oral HSV using surface under the cumulative ranking (SUCRA). Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to assess the certainty of the evidence. In total, 16 articles were included. The pooled relative risk (RR) to develop oral HSV infection in the acyclovir group was 0.17 (95% CI: 0.10, 0.30), compared to 0.22 (95% CI: 0.06, 0.77) in the valacyclovir group. Acyclovir ranked highest for the prevention of oral HSV followed by valacyclovir. Subgroup analysis with different acyclovir regimens revealed that the best regimens in terms of HSV-1 prevention were 750 mg/m2 acyclovir administered intravenously followed by 1600 mg per day orally. Acyclovir (250 mg/m2 per day) administered intravenously was the least effective against the prevention of oral HSV.

Electrochemical Oxidation and Determination of Antiviral Drug Acyclovir by Modified Carbon Paste Electrode With Magnetic CdO Nanoparticles

With the development of nanomaterials in electrochemical sensors, the use of nanostructures to modify the electrode surface has been shown to improve the kinetics of the electron transfer process. In this study, a sensor was developed for the electrochemical determination of Acyclovir (ACV) based on the modified carbon paste electrode (CPE) by CdO/Fe₃O₄. The magnetic CdO nanoparticles characterization was studied by energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). To study of the modified CPE surface morphology, scanning electron microscopy (SEM) was used. At the optimal conditions, a noteworthy enhancement in the electrochemical behavior of ACV was observed at the surface of the modified CPE compared to the unmodified CPE. A detection limit of 300 nM and a linear range of 1–100 μM were obtained for the quantitative monitoring of ACV at the modified CPE surface using differential pulse voltammetry (DPV) in phosphate buffer. The RSD% (relative standard deviation) of the electrode response was <4.3% indicating the development of a high precision method. Also, satisfactory results were obtained in the determination of ACV with the modified electrode in tablet, blood serum, and urine samples with a satisfactory relative recovery (RR%) in the range of 94.0–104.4%.

Acyclovir-Loaded Solid Lipid Nanoparticles: Optimization, Characterization and Evaluation of Its Pharmacokinetic Profile

Acyclovir is an antiviral drug used for the treatment of herpes simplex virus infection. Its oral bioavailability is low; therefore, frequent and high doses are prescribed for optimum therapeutic efficacy. Moreover, the current therapeutic regimen of acyclovir is associated with unwarranted adverse effects, hence prompting the need for a suitable drug carrier to overcome these limitations. This study aimed to develop solid lipid nanoparticles (SLNs) as acyclovir carriers and evaluate their in vivo pharmacokinetic parameters to prove the study hypothesis. During the SLN development process, response surface methodology was exploited to optimize the composition of solid lipid and surfactant. Optimum combination of Biogapress Vegetal 297 ATO and Tween 80 was found essential to produce SLNs of 134 nm. The oral bioavailability study showed that acyclovir-loaded SLNs possessed superior oral bioavailability when compared with the commercial acyclovir suspension. The plasma concentration of acyclovir-loaded SLNs was four-fold higher than the commercial suspension. Thus, this investigation presented promising results that the method developed for encapsulation of acyclovir offers potential as an alternative pathway to enhance the drug’s bioavailability. In conclusion, this study exhibited the feasibility of SLNs as an oral delivery vehicle for acyclovir and therefore represents a new promising therapeutic concept of acyclovir treatment via a nanoparticulate drug delivery system.

In Vitro and In Vivo Activity, Tolerability, and Mechanism of Action of BX795 as an Antiviral against Herpes Simplex Virus 2 Genital Infection

Herpes simplex virus type 2 (HSV-2) causes recurrent lesions in the anogenital area that may be transmitted through sexual encounters. Nucleoside analogs, such as acyclovir (ACV), are currently prescribed clinically to curb this infection. However, in some cases, reduced efficacy has been observed due to the emergence of resistance against these drugs. In our previous study, we reported the discovery of a novel anti-HSV-1 small molecule, BX795, which was originally used as an inhibitor of TANK-binding kinase 1 (TBK1). In this study, we report the antiviral efficacy of BX795 on HSV-2 infection in vaginal epithelial cells in vitro at 10 μM and in vivo at 50 μM. Additionally, through biochemical assays in vitro and histopathology in vivo, we show the tolerability of BX795 in vaginal epithelial cells at concentrations as high as 80 μM. Our investigations also revealed that the mechanism of action of BX795 antiviral activity stems from the reduction of viral protein translation via inhibition of protein kinase B phosphorylation. Finally, using a murine model of vaginal infection, we show that topical therapy using 50 μM BX795 is well tolerated and efficacious in controlling HSV-2 replication.

Antiviral Activities of Quercetin and Isoquercitrin Against Human Herpesviruses

We previously reported that the ethyl acetate (EtOAc) fraction of a 70% ethanol extract of Elaeocarpus sylvestris (ESE) inhibits varicella-zoster virus (VZV) and human cytomegalovirus (HCMV) replication in vitro. PGG (1,2,3,4,6-penta-O-galloyl-ß-D-glucose) is a major chemical constituent of the EtOAc fraction of ESE that inhibits VZV but not HCMV replication. In this study, we comprehensively screened the chemical compounds identified in the EtOAc fraction of ESE for potential antiviral properties. Among the examined compounds, quercetin and isoquercitrin displayed potent antiviral activities against both VZV and HCMV with no significant cytotoxic effects. Both compounds strongly suppressed the expression of VZV and HCMV immediate–early (IE) genes. Our collective results indicated that, in addition to PGG, quercetin and isoquercitrin are bioactive compounds in the EtOAc fraction of ESE that effectively inhibit human herpesvirus replication.

BX795 demonstrates potent antiviral benefits against herpes simplex Virus-1 infection of human cell lines

Herpes simplex virus-1 (HSV-1) infection is known to cause skin blisters, keratitis as well as deadly cases of encephalitis in some situations. Only a few therapeutic modalities are available for this globally prevalent infection. Very recently, a small molecule BX795 was identified as an inhibitor of HSV-1 protein synthesis in an ocular model of infection. In order to demonstrate its broader antiviral benefits, this study was aimed at evaluating the antiviral efficacy, mode-of-action, and toxicity of BX795 against HSV-1 infection of three human cell lines: HeLa, HEK, and HCE. Several different assays, including cell survival analysis, imaging, plaque analysis, Immunoblotting, and qRT-PCR, were performed. In all cases, BX795 demonstrated low toxicity at therapeutic concentration and showed strong antiviral benefits. Quite interestingly, cell line-dependent differences in the mechanism of antiviral action and cytokine response to infection were seen upon BX795 treatment. Taken together, our results suggest that BX795 may exert its antiviral benefits via cell-line specific mechanisms.

Mechanisms of antimicrobial-induced nephrotoxicity in children

Drug-induced nephrotoxicity is responsible for 20% to 60% of cases of acute kidney injury in hospitalized patients and is associated with increased morbidity and mortality in both children and adults. Antimicrobials are one of the most common classes of medications prescribed globally and also among the most common causes of nephrotoxicity. A broad range of antimicrobial agents have been associated with nephrotoxicity, but the features of kidney injury vary based on the agent, its mechanism of injury and the site of toxicity within the kidney. Distinguishing nephrotoxicity caused by an antimicrobial agent from other potential inciting factors is important to facilitate both early recognition of drug toxicity and prompt cessation of an offending drug, as well as to avoid unnecessary discontinuation of an innocuous therapy. This review will detail the different types of antimicrobial-induced nephrotoxicity: acute tubular necrosis, acute interstitial nephritis and obstructive nephropathy. It will also describe the mechanism of injury caused by specific antimicrobial agents and classes (vancomycin, aminoglycosides, polymyxins, antivirals, amphotericin B), highlight the toxicodynamics of these drugs and provide guidance on administration or monitoring practices that can mitigate toxicity, when known. Particular attention will be paid to paediatric patients, when applicable, in whom nephrotoxin exposure is an often-underappreciated cause of kidney injury.

Current and Emerging Therapies for Ocular Herpes Simplex Virus Type-1 Infections

Herpes simplex virus type-1 (HSV-1) is a neurotropic, double-stranded DNA virus that can cause a wide variety of diseases, including many ocular pathologies. It is one of the leading causes of infectious blindness in the United States. Because of its ubiquitous nature and its potential to cause serious ocular maladies, there is a significant need for more effective antiviral therapies against ocular HSV-1. In this review, we discuss the lifecycle of HSV-1 as it pertains to corneal infections and the clinically approved as well as emerging treatments to combat HSV-1 infections. We also highlight some newly identified host targets for the antiviral drug development.

An off-target effect of BX795 blocks herpes simplex virus type 1 infection of the eye

Herpes simplex virus type 1 (HSV-1) causes recurrent mucocutaneous lesions in the eye that may advance to corneal blindness. Nucleoside analogs exemplified by acyclovir (ACV) form the primary class of antiherpetic drugs, but this class suffers limitations due to the emergence of viral resistance and other side effects. While studying the molecular basis of ocular HSV-1 infection, we observed that BX795, a commonly used inhibitor of TANK-binding kinase 1 (TBK1), strongly suppressed infection by multiple strains of HSV-1 in transformed and primary human cells, cultured human and animal corneas, and a murine model of ocular infection. Our investigations revealed that the antiviral activity of BX795 relies on targeting Akt phosphorylation in infected cells, leading to the blockage of viral protein synthesis. This small-molecule inhibitor, which was also effective against an ACV-resistant HSV-1 strain, shows promise as an alternative to existing drugs and as an effective topical therapy for ocular herpes infection. Collectively, our results obtained using multiple infection models and virus strains establish BX795 as a promising lead compound for broad-spectrum antiviral applications in humans.

Drug-encapsulated carbon (DECON): A novel platform for enhanced drug delivery

Current drug-delivery systems are designed primarily for parenteral applications and are either lipid or polymer drug conjugates. In our quest to inhibit herpes simplex virus infection via the compounds found in commonly used cosmetic products, we found that activated carbon particles inhibit infection and, in addition, substantially improve topical delivery and, hence, the efficacy of a common antiviral drug, acyclovir (ACV). Our in vitro studies demonstrate that highly porous carbon structures trapped virions, blocked infection and substantially improved efficacy when ACV was loaded onto them. Also, using murine models of corneal and genital herpes infections, we show that the topical use of drug-encapsulated carbon (DECON) reduced dosing frequency, shortened treatment duration, and exhibited higher therapeutic efficacy than currently approved topical or systemic antivirals alone. DECON is a nontoxic, cost-effective and nonimmunogenic alternative to current topical drug-delivery systems that is uniquely triggered for drug release by virus trapping.

The footprints of mitochondrial impairment and cellular energy crisis in the pathogenesis of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and Fanconi's syndrome: A comprehensive review

Fanconi's Syndrome (FS) is a disorder characterized by impaired renal proximal tubule function. FS is associated with a vast defect in the renal reabsorption of several chemicals. Inherited and/or acquired conditions seem to be connected with FS. Several xenobiotics including many pharmaceuticals are capable of inducing FS and nephrotoxicity. Although the pathological state of FS is well described, the exact underlying etiology and cellular mechanism(s) of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and FS are not elucidated. Constant and high dependence of the renal reabsorption process to energy (ATP) makes mitochondrial dysfunction as a pivotal mechanism which could be involved in the pathogenesis of FS. The current review focuses on the footprints of mitochondrial impairment in the etiology of xenobiotics-induced FS. Moreover, the importance of mitochondria protecting agents and their preventive/therapeutic capability against FS is highlighted. The information collected in this review may provide significant clues to new therapeutic interventions aimed at minimizing xenobiotics-induced renal injury, serum electrolytes imbalance, and FS.

Outcomes with acyclovir treatment in herpes simplex encephalitis after surgery for solid CNS tumors: a case report and systematic review of the literature

Background

Herpes simplex encephalitis (HSE) occurring within 30 days after neurosurgery for solid CNS tumors is underrecognized and underreported but remains important because of high morbidity and mortality. We present the case of a 41-year-old woman who had HSE after craniopharyngioma surgery, and delayed recognition and treatment led to a poor outcome. Subsequently, we review reported HSE cases after neurosurgery for solid CNS tumors and describe outcomes after treatment with and without acyclovir.

Methods

A literature search was performed for cases meeting the above criteria. Information was gathered regarding patient demographics, tumor types, symptoms, diagnostic workup, therapy, and outcomes.

Results

Eighteen cases were studied. Encephalopathy, fever, and seizures were the most common symptoms. A majority of patients (78%) received IV acyclovir, with a 79% survival rate with treatment. Mortality rate was 100% in untreated cases. The median time to starting acyclovir was 17 postoperative days (range, 8-53 days). Most patients received steroids, but its use was not associated with a specific outcome.

Conclusions

HSE may develop following neurosurgical resection, and the threshold for suspicion of this condition should be extremely low in a patient who shows compatible symptoms (encephalopathy, fever, or seizures) or does not recover as planned. Moreover, in case of suspicion of HSE, acyclovir should be promptly started until infection can be definitely ruled out. A delay in diagnosis of HSE and failure to treat may result in severe morbidity as well as mortality. This observation may warrant further study.

Oral acyclovir induced hypokalemia and acute tubular necrosis a case report

Background

Acyclovir is one of the most common prescribed antiviral drugs. Acyclovir nephrotoxicity occurs in approximately 12–48% of cases. It can present in clinical practice as acute kidney injury (AKI), crystal-induced nephropathy, acute tubulointerstitial nephritis, and rarely, as tubular dysfunction. Electrolytes abnormalities like hypokalemia, were previously described only when given intravenously.

Case presentation

A 54 year-old female presented with weakness and lower extremities paresis, nausea and vomiting after receiving oral acyclovir. Physical examination disclosed a decrease in the patellar osteotendinous reflexes (++ / ++++). Laboratory data showed a serum creatinine level of 2.1 mg/dL; serum potassium 2.1 mmol/L. Kidney biopsy was obtained; histological findings were consistent with acute tubular necrosis and acute tubulointerstitial nephritis. The patient was advised to stop the medications and to start with oral and intravenous potassium supplement, symptoms improved and continued until serum potassium levels were > 3.5 meq/L.

Conclusions

The case reported in this vignette is unique since it is the first one to describe hypokalemia associated to acute tubular necrosis induced by oral acyclovir.

Valacyclovir Neurotoxicity and Nephrotoxicity in an Elderly Patient Complicated by Hyponatremia

A 66-year-old women with no history of renal disease was admitted due to a coma and acute kidney injury with a serum creatinine level of 7.44 mg/dL which were ascribed to valacyclovir neurotoxicity and nephrotoxicity, respectively. She had received valacyclovir at a standard dosage for the treatment of herpes zoster and was finally discharged, having fully returned to her normal baseline mental status with a recovered serum creatinine level of 0.68 mg/dL. We feel that awareness of this pathology remains a challenge for physicians and therefore strongly recommend the further accumulation of experiences similar to our own. Our experience underscores the pitfalls of administering valacyclovir to elderly patients who barely appear to have a favorable renal function. Several concerns regarding the therapeutic management, including blood purification strategies, that emerged in this case are also discussed.

Acyclovir-induced thrombotic microangiopathy

Acyclovir is a commonly used antiviral drug. Acute kidney injury (AKI) due to intratubular crystal precipitation and interstitial nephritis is well known. Here we present a case of acyclovir induced AKI in a 61 year old male with herpes zoster, which presented like thrombotic microangiopathy with acute interstitial nephritis. This is the first case report on acyclovir causing thrombotic microaniopathy with partial improvement in renal function after plasmapharesis.

Management of adult infectious encephalitis in metropolitan France

Infectious encephalitis is a severe disease leading to a high mortality and morbidity. The most frequent causes include Herpes simplex virus, Varicella Zoster virus, Listeria monocytogenes, and Mycobacterium tuberculosis. Urgent treatment is required (anti-infective therapy and nonspecific supportive care). The aim of this study was to define treatment strategy, empirical and after microbiological documentation at 48hours, through a systematic literature review.

Acute renal injury induced by valacyclovir hydrochloride: A case report

Acyclovir has been a frequently used antiviral agent in the clinical treatment of leukemia, acute encephalitis, malignant tumor and herpes simplex. The adverse effects of this drug have been widely described in clinical practice. In the present study, a case of a 35-year-old female patient diagnosed with herpes simplex, who developed acute renal injury following treatment with valacyclovir hydrochloride, is described. Kidney biopsy, light microscopy and laboratory examination were performed, and all findings revealed the signs of evident vacuolar degeneration of capillary endothelial and renal tubular epithelial cells, erythrocyte aggregation in partial renal tubule and microvilli exfoliation from epithelial cells. Renal interstitial edema was clearly identified. The clinical evidence observed from this female patient indicated that renal functions should be closely monitored during valacyclovir hydrochloride administration. A variety of effective measures, such as hydration, alkalizing urine, promoting the discharge of medication and the use of antagonists are recommended following the administration of antiviral agents.

A metabolic profiling analysis of the nephrotoxicity of acyclovir in rats using ultra performance liquid chromatography/mass spectrometry

Acyclovir (ACV) exposure is a common cause of acute kidney injury (AKI). The toxicity mechanism of ACV has always been a matter of debate. The present study investigated into the time-effect relationship and dose-effect relationship of ACV-induced nephrotoxicity in rats using metabonomics. Twenty-four rats were randomly divided into four groups: a 0.9% NaCl solution group, and 100, 300, and 600mg/kg ACV-treated groups; the ACV or vehicle solution was administered with a single intravenous injection. Urine was collected at different time periods (12h before administration, and 0-6h, 7-12h, and 13-24h after administration). Routine urinalysis was conducted by a urine automatic analyzer. Renal markers, including urine urea nitrogen, urine creatinine, and urinary N-acetyl-β-d-glucosaminidase (NAG) activity, were determined using established protocols. Urinary metabolites were evaluated using ultra performance liquid chromatography/mass spectrometry (UPLC/MS). In the ACV-treated rats, increased levels of protein (PRO), occult blood (BLD), white blood cell (WBC), and NAG activity in urine were observed, while the urine creatinine and urea nitrogen levels showed a decrease compared with the control. Moreover, urine metabolites significantly changed after the treatment with ACV, and all the effects induced by ACV were dose-time dependent. Finally, 4 metabolites (guanine, 4-guanidinobutyric acid, creatinine, and urea) were identified, which can be used for further research on the mechanism of ACV-induced nephrotoxicity.

Dosing Practices of Intravenous Acyclovir for Herpes Encephalitis in Obesity: Results of a Pharmacist Survey

BACKGROUND

Dosing of intravenous acyclovir for herpes encephalitis in obese patients is recommended to be based on ideal body weight. However, limited data support this recommendation, and recent data suggest this may lead to underdosing.

OBJECTIVE

To determine national dosing practices of intravenous acyclovir across a range of patient weights.

METHODS

A survey was distributed to members of the American College of Clinical Pharmacy Critical Care and Infectious Diseases Practice & Research Networks listservs. Data collected included demographic information and dosing of acyclovir, given consistent patient cases with varying patient weight.

RESULTS

A total of 264 pharmacists participated in the survey, with 240 (90.9%) participants completing the survey. Participants were predominately clinical pharmacists. As patient weight increased, respondents were more apt to dose based on an adjusted body weight, with dosing in the obese and morbidly obese showing a clear lack of consistency.

CONCLUSIONS

Intravenous dosing of acyclovir for herpes encephalitis is variable, especially in obese patients, and does not reflect recommendations. Limited data provide conflicting recommendations for dosing in obese patients, and future studies are necessary to optimize patient outcomes and prevent toxicity.

Valacyclovir-Induced Acute Kidney Injury in Japanese Patients Based on the PMDA Adverse Drug Reactions Reporting Database

BACKGROUND

More than 250,000 reports of adverse drug events were included in the database of the Pharmaceuticals and Medical Devices Agency (PMDA) in Japan. However, these data have not been utilized sufficiently for analysis. While valacyclovir is the antiviral agent used worldwide, it is reported to induce nephrotoxicity. The aim of this study was to clarify the profiles of valacyclovir-induced adverse events using the PMDA database.

METHODS

Case reports were screened in the PMDA adverse event database from 2004 to 2011. The profiles of patients with acute kidney injury (AKI) were analyzed by sex, age, diseases, concomitant suspected drugs, and outcomes.

RESULTS

A total of 514 kidney-related adverse events were detected, and 344 were cases that included AKI. Of the AKI cases, 246 patients (71.5%) were female. There were 145 patients who were 70 to 79 years of age, which was the most affected of all age groups. Of the 344 patients, 183 patients had hypertension, and 65 had diabetes. Valacyclovir was the only drug used among 257 patients (74.1%).

CONCLUSIONS

There were many reports of AKI involving valacyclovir and females, particularly in the 70- to 79-year age group in Japan. The results suggest that these patients were most likely to develop AKI after valacyclovir treatment.

Comparison of renal function indicators according to hydration volume in patients receiving intravenous acyclovir with CNS infection

PURPOSE

We aimed to compare the changes in renal function indicators as a function of hydration volume in patients treated with acyclovir for suspected herpes simplex virus (HSV) infection.

METHOD

We obtained data from 216 acyclovir-treated patients hospitalized between 2007 and 2012 for suspected HSV infection. Intravenous hydration volume and renal function indicators (serum creatinine [sCr], blood urea nitrogen [BUN], glutamate oxaloacetate transferase, glutamate pyruvate transferase, and uric acid levels; estimated glomerular filtration rate [eGFR]; and urine pH) were compared among the patients. The indicators were assessed before acyclovir infusion and after 3 days of acyclovir infusion.

RESULTS

Before acyclovir infusion, all the indicators were within normal ranges in all groups (hydration volume lower than 2 L/day, higher than 2 L/day, and without hydration). After acyclovir infusion for 3 days, the groups without hydration and with a volume lower than 2 L/day showed increased sCr (2.22 ± 0.51 and 1.70 ± 0.35 mg/dl, respectively), BUN levels (28.33 ± 0.57 and 22.14 ± 7.95 mg/dl, respectively), and glutamate oxaloacetate transferase (48.00 ± 2.65 IU/L, without hydration) and eGFRs lower than the normal range (53.03 ± 3.05 and 59.66 ± 10.25 ml/min, respectively; p < .001 for all parameters). The renal function indicators were within normal limits in the group with a hydration volume higher than 2 L/day.

CONCLUSIONS

Renal function indicators in acyclovir-treated patients varied according to hydration volume. Health care providers should consider whether the hydration volume in each patient receiving intravenous acyclovir is sufficient for preventing nephropathy.

Acute kidney injury due to acyclovir

Acyclovir is an antiviral agent widely used in herpetic infections in children. Although acyclovir is generally well tolerated, severe nephrotoxicity has been reported in some cases. In this report, we present a 16-year-old girl who developed acute renal failure due to acyclovir treatment and who needed repetitive hemodialysis. Renal biopsy was performed in order to confirm the diagnosis. A diagnosis of drug-related acute tubulointerstitial nephritis with focal tubular necrosis was made.

Acyclovir-induced acute renal failure and the importance of an expanding waist line

A 23-year-old gentleman with no significant medical history other than obesity was admitted with a history of balance problems, double vision and strange behaviour following a fall from bed. Systems examination was unremarkable. The patient was given intravenous acyclovir and intravenous ceftriaxone given the suspicion of encephalitis/meningitis. Investigations including routine bloods, CT/MRI Head and lumbar puncture were unremarkable. Within 48&emsp14;h of commencing intravenous acyclovir, there was a marked deterioration in renal function. On stopping acyclovir therapy, renal function improved back to baseline. No other cause for deterioration in renal function was identified. The most likely cause for acute renal failure was secondary to acyclovir therapy. This has been well documented and is due to intratubular crystal precipitation. Moreover, in this case nephrotoxicity is likely secondary to the large boluses of intravenous acyclovir that had been given as prescribed according to the total body weight.