Genistein improves renal disease in a mouse model of nephropathic cystinosis: a comparison study with cysteamine.

Cysteamine is currently the only therapy for nephropathic cystinosis. It significantly improves life expectancy and delays progression to end-stage kidney disease; however, it cannot prevent it. Unfortunately, compliance to therapy is often weak, particularly during adolescence. Therefore, finding better treatments is a priority in the field of cystinosis. Previously, we found that genistein, an isoflavone particularly enriched in soy, can revert part of the cystinotic cellular phenotype that is not sensitive to cysteamine in vitro. To test the effects of genistein in vivo, we fed 2-month-old wild-type and Ctns-/- female mice with either a control diet, a genistein-containing diet or a cysteamine-containing diet for 14 months. Genistein (160 mg/kg/day) did not affect the growth of the mice or hepatic functionality. Compared with untreated mice at 16 months, Ctns-/- mice fed with genistein had lower cystine concentrations in their kidneys, reduced formation of cystine crystals, a smaller number of LAMP1-positive structures and an overall better-preserved parenchymal architecture. Cysteamine (400 mg/kg/day) was efficient in reverting the lysosomal phenotype and in preventing the development of renal lesions. These preclinical data indicate that genistein ameliorates kidney injury resulting from cystinosis with no side effects. Genistein therapy represents a potential treatment to improve the outcome for patients with cystinosis.

MFSD12 depletion reduces cystine accumulation without improvement in proximal tubular function in experimental models for cystinosis.

Cystinosis is an autosomal recessive lysosomal storage disorder, caused by mutations in the CTNS gene, resulting in an absent or altered cystinosin (CTNS) protein. Cystinosin exports cystine out of the lysosome, with a malfunction resulting in cystine accumulation and a defect in other cystinosin-mediated pathways. Cystinosis is a systemic disease, but the kidneys are the first and most severely affected organs. In the kidney, the disease initially manifests as a generalized dysfunction in the proximal tubules (also called renal Fanconi syndrome). MFSD12 is a lysosomal cysteine importer that directly affects the cystine levels in melanoma cells, HEK293T cells, and cystinosis patient-derived fibroblasts. In this study, we aimed to evaluate MFSD12 mRNA levels in cystinosis patient-derived proximal tubular epithelial cells (ciPTECs) and to study the effect of MFSD12 knockout on cystine levels. We showed similar MFSD12 mRNA expression in patient-derived ciPTECs in comparison with the control cells. CRISPR MFSD12 knockout in a patient-derived ciPTEC (CTNSΔ57kb) resulted in significantly reduced cystine levels. Furthermore, we evaluated proximal tubular reabsorption after injection of mfsd12a translation-blocking morpholino (TB MO) in a ctns-/- zebrafish model. This resulted in decreased cystine levels but caused a concentration-dependent increase in embryo dysmorphism. Furthermore, the mfsd12a TB MO injection did not improve proximal tubular reabsorption or megalin expression. In conclusion, MFSD12 mRNA depletion reduced cystine levels in both tested models without improvement of the proximal tubular function in the ctns-/- zebrafish embryo. In addition, the apparent toxicity of higher mfsd12a TB MO concentrations on the zebrafish development warrants further evaluation.NEW & NOTEWORTHY In this study, we show that MFSD12 depletion with either CRISPR/Cas9-mediated gene editing or a translation-blocking morpholino significantly reduced cystine levels in cystinosis ciPTECs and ctns-/- zebrafish embryos, respectively. However, we observed no improvement in the proximal tubular reabsorption of dextran in the ctns-/- zebrafish embryos injected with mfsd12a translation-blocking morpholino. Furthermore, a negative effect of the mfsd12a morpholino on the zebrafish development warrants further investigation.

Oral Viscous Budesonide in Children With Eosinophilic Esophagitis After Repaired Esophageal Atresia: A Clinical Trial.

OBJECTIVES: A high prevalence of eosinophilic esophagitis (EoE) has been reported in children with repaired esophageal atresia (EA). Topical steroids proved to be an effective and safe therapy in EoE, although not approved in pediatrics. We report the results of the first clinical trial of oral viscous budesonide (OVB) performed in children with EoE after repaired esophageal atresia (EoE-EA). METHODS: This open-label, single-arm, phase 2 clinical trial with randomized pharmacokinetic sampling, was conducted at the Bambino Gesù Children's Hospital between September 2019 and June 2021. EoE-EA patients received an age-banded dose of OVB twice daily for 12 weeks and were endoscopically evaluated. The primary endpoint was the rate of patients achieving histological remission. Secondary endpoints included clinical and endoscopic benefit after treatment, and safety assessments. RESULTS: Eight consecutive EA-EoE patients were enrolled (median age 9.1 years, interquartile range 5.5). Of these, 5 received 0.8 mg and 3 received 1.0 mg twice daily of OVB. Histological remission was obtained in all but 1 patient (87.5%). The clinical score showed significant improvement at the end of treatment in all patients. No endoscopic features of EoE were found after treatment. No treatment-emergent adverse event occurred. CONCLUSION: OVB is an effective, safe, and well-tolerated formulation of budesonide for use in pediatric patients with EoE-EA.

Cell-Based Phenotypic Drug Screening Identifies Luteolin as Candidate Therapeutic for Nephropathic Cystinosis.

BACKGROUND: Mutations in the gene that encodes the lysosomal cystine transporter cystinosin cause the lysosomal storage disease cystinosis. Defective cystine transport leads to intralysosomal accumulation and crystallization of cystine. The most severe phenotype, nephropathic cystinosis, manifests during the first months of life, as renal Fanconi syndrome. The cystine-depleting agent cysteamine significantly delays symptoms, but it cannot prevent progression to ESKD and does not treat Fanconi syndrome. This suggests the involvement of pathways in nephropathic cystinosis that are unrelated to lysosomal cystine accumulation. Recent data indicate that one such potential pathway, lysosome-mediated degradation of autophagy cargoes, is compromised in cystinosis. METHODS: To identify drugs that reduce levels of the autophagy-related protein p62/SQSTM1 in cystinotic proximal tubular epithelial cells, we performed a high-throughput screening on the basis of an in-cell ELISA assay. We then tested a promising candidate in cells derived from patients with, and mouse models of, cystinosis, and in preclinical studies in cystinotic zebrafish. RESULTS: Of 46 compounds identified as reducing p62/SQSTM1 levels in cystinotic cells, we selected luteolin on the basis of its efficacy, safety profile, and similarity to genistein, which we previously showed to ameliorate other lysosomal abnormalities of cystinotic cells. Our data show that luteolin improves the autophagy-lysosome degradative pathway, is a powerful antioxidant, and has antiapoptotic properties. Moreover, luteolin stimulates endocytosis and improves the expression of the endocytic receptor megalin. CONCLUSIONS: Our data show that luteolin improves defective pathways of cystinosis and has a good safety profile, and thus has potential as a treatment for nephropathic cystinosis and other renal lysosomal storage diseases.

A new HPLC-DAD method for contemporary quantification of 10 antibiotics for therapeutic drug monitoring of critically ill pediatric patients.

The common practice of therapeutic drug monitoring (TDM) involves the quantification of drug plasma concentrations at a specific time in a dosing window. Although TDM for antibiotics is not considered mandatory, it may represent a valid tool for clinicians in order to limit antibiotic resistance and avoid therapeutic failures. The aim of our study was to develop and validate a high-performance liquid chromatography-diode array detection method for simultaneous quantification of 10 antibiotics in plasma. This method has a fast analytical procedure that uses the same chromatographic conditions to quantify ceftazidime, ceftriaxone, meropenem, ertapenem, ciprofloxacin, tigecycline, ampicillin, levofloxacin and piperacillin, plus the ß-lactamase inhibitor tazobactam. Method validation was ensured by testing selectivity, accuracy, precision, limits of detection and quantification, recovery and stability. The calibration ranges, established accordingly to the expected plasma concentration in patients, showed a coefficient of determination >0.996 for all compounds. Within- and between-days precisions reported a coefficient of variation >15%. Similarly, the accuracy evaluation reported a relative standard deviation of <10% for each antibiotic. The recovery ranged between 97 and 103% for all compounds. This method could represent a useful tool for TDM of antibiotics.

Therapeutic Drug Monitoring Is a Feasible Tool to Personalize Drug Administration in Neonates Using New Techniques: An Overview on the Pharmacokinetics and Pharmacodynamics in Neonatal Age.

Therapeutic drug monitoring (TDM) should be adopted in all neonatal intensive care units (NICUs), where the most preterm and fragile babies are hospitalized and treated with many drugs, considering that organs and metabolic pathways undergo deep and progressive maturation processes after birth. Different developmental changes are involved in interindividual variability in response to drugs. A crucial point of TDM is the choice of the bioanalytical method and of the sample to use. TDM in neonates is primarily used for antibiotics, antifungals, and antiepileptic drugs in clinical practice. TDM appears to be particularly promising in specific populations: neonates who undergo therapeutic hypothermia or extracorporeal life support, preterm infants, infants who need a tailored dose of anticancer drugs. This review provides an overview of the latest advances in this field, showing options for a personalized therapy in newborns and infants.

Chronic liver involvement in urea cycle disorders.

The increased survival of urea cycle disorders (UCDs) patients has led the attention to clinical manifestations that characterize the long-term disease course. Acute and chronic liver disease have been anecdotally reported since the very first description of UCDs. However, a detailed analysis of long-term liver involvement in large patient cohorts is still needed. Chronic liver damage in UCDs has probably a multifactorial origin, but the specific underlying mechanisms of liver disease have not yet been well elucidated. In this study, we report on chronic liver involvement and on associated metabolic abnormalities in a large cohort of 102 UCD patients, followed by two reference centers in Italy. Chronic liver involvement was observed in over 60% of UCDs patients, and comparison between individual diseases showed a significant higher frequency in argininosuccinate lyase deficiency (ASLD) and in hyperornithinemia-hyperammonemia-homocitrullinemia (HHH) syndrome with elevation of transaminases and of gamma-GT in ASLD, and of alpha-fetoprotein in HHH syndrome. Also, consistent with a chronic hepatic dysfunction, ultrasound examination revealed more pronounced abnormalities in ASLD and in HHH syndrome, when compared to other UCDs. Our study highlights in a large UCDs patients' cohort that chronic liver disease is a common finding in UCDs, often with a distinct phenotype between different diseases. Furthers studies are needed to elucidate the specific involvement of different metabolic pathways in the pathogenesis of liver dysfunction in UCDs.

Validation of Heel Stick Microsampling To Optimize Micafungin Doses in Neonates and Young Infants.

Major gaps exist in our knowledge of antimicrobial pharmacokinetics in critically ill neonates and infants that require validated microsampling and bioanalysis methods to support therapeutic drug monitoring. We compared serially collected intravenous (i.v.) and heel stick capillary (HSC)-sampled plasma concentrations of micafungin (8 mg/kg) in eight infants born preterm with systemic candidiasis. The mean (standard deviation) micafungin area under the plasma concentration-time curve to infinity (AUCinf) was 316 (65.0) h · mg/liter based on HSC concentrations that strongly correlated (R2 = 0.92) with i.v. values to support dose adjustment.

Isavuconazole: Case Report and Pharmacokinetic Considerations.

Invasive fungal disease (IFD) is one of the major causes of morbidity and mortality in immunocompromised patients. Voriconazole (VCZ) and posaconazole (PCZ) remain the most widely used antifungals for the prophylaxis and treatment of IFD. However, VCZ and PCZ are liable for drug-drug interactions and show a pharmacokinetic variability that requires therapeutic drug monitoring (TDM). Isavuconazole (IVZ) is a newest generation triazole antifungal approved for the treatment of invasive aspergillosis (IA) in adult patients and for the treatment of invasive mucormycosis in adult patients for whom treatment with amphotericin B is inappropriate. In clinical trials, IVZ showed linear pharmacokinetics and little or no evidence for interactions with other drugs. There is only modest evidence on IVZ pharmacokinetics and TDM in real-life settings. Here, we report on IVZ pharmacokinetics in a young adult with Ph chromosome-negative acute lymphoblastic leukemia (ALL) who developed a "probable" IA during induction chemotherapy. The patient was initially treated with VCZ, but she developed a severe hepatic toxicity that was associated to the high plasma levels of VCZ. Therefore, VCZ was discontinued and the patient was switched to IVZ. After a loading dose of IVZ, the patient remained on IVZ for 5 months while also receiving standard maintenance chemotherapy for ALL. At day 65 after the start of IVZ, the patient experienced a significant hepatic toxicity; however, no change in IVZ plasma concentrations was observed in the face of a concomitant administration of many other drugs (cancer drugs, antiemetics, other anti-infectives). Hepatic toxicity resolved after discontinuing maintenance chemotherapy but not IVZ. These results show that (i) IVZ plasma concentrations remained stable throughout and were not affected by concomitant ALL therapy, and (ii) there was no relation between IVZ plasma concentration and hepatic toxicity. Thus, in clinical practice IVZ may not require TDM.

Evaluation of plasma cholestane-3ß,5α,6ß-triol and 7-ketocholesterol in inherited disorders related to cholesterol metabolism.

Oxysterols are intermediates of cholesterol metabolism and are generated from cholesterol via either enzymatic or nonenzymatic pathways under oxidative stress conditions. Cholestan-3ß,5α,6ß-triol (C-triol) and 7-ketocholesterol (7-KC) have been proposed as new biomarkers for the diagnosis of Niemann-Pick type C (NP-C) disease, representing an alternative tool to the invasive and time-consuming method of fibroblast filipin test. To test the efficacy of plasma oxysterol determination for the diagnosis of NP-C, we systematically screened oxysterol levels in patients affected by different inherited disorders related with cholesterol metabolism, which included Niemann-Pick type B (NP-B) disease, lysosomal acid lipase (LAL) deficiency, Smith-Lemli-Opitz syndrome (SLOS), congenital familial hypercholesterolemia (FH), and sitosterolemia (SITO). As expected, NP-C patients showed significant increase of both C-triol and 7-KC. Strong increase of both oxysterols was observed in NP-B and less pronounced in LAL deficiency. In SLOS, only 7-KC was markedly increased, whereas in both FH and in SITO, oxysterol concentrations were normal. Interestingly, in NP-C alone, we observed that plasma oxysterols correlate negatively with patient's age and positively with serum total bilirubin, suggesting the potential relationship between oxysterol levels and hepatic disease status. Our results indicate that oxysterols are reliable and sensitive biomarkers of NP-C.

High-Dose Micafungin for Preterm Neonates and Infants with Invasive and Central Nervous System Candidiasis.

High doses of micafungin are advocated in neonates with systemic candidiasis, but limited pharmacokinetic (PK) and safety data are available to support their use. Eighteen preterm neonates and infants with systemic candidiasis, three of whom had meningitis, were treated for at least 14 days with 8 to 15 mg/kg of body weight/day of intravenous micafungin. Plasma micafungin concentrations (four measurements for each patient) were determined after the third dose, and the cerebrospinal fluid (CSF) micafungin concentrations in three patients were also obtained. Population PK analyses were used to identify the optimal model, and the model was further validated using external data (n = 5). The safety of micafungin was assessed by measurement of the levels of liver and kidney function biomarkers. The mean age and weight at the initiation of treatment were 2.33 months (standard deviation [SD], 1.98 months) and 3.24 kg (SD, 1.61 kg), respectively. The optimal PK model was one that scaled plasma clearance to weight and the transaminase concentration ratio. The CSF of three patients was sampled, and the observed concentrations were between 0.80 and 1.80 mg/liter. The model-predicted mean micafungin area under the concentration-time curve over 24 h was 336 mg · h/liter (SD, 165 mg · h/liter) with the 10-mg/kg/day dosage. Eighteen of the 23 subjects (78.2%) had clinical resolution of their infection, but 5 had neurologic impairments. Among the transaminases, alkaline phosphatase measurements were significantly higher posttreatment, with a geometric mean ratio of 1.17 (90% confidence interval, 1.01, 1.37). Furthermore, marked elevations in the gamma-glutamyltransferase (GGT) level were observed in three patients treated with 10- to 15-mg/kg/day doses, and improvement of the GGT level was noted after a dose reduction. Higher weight-based doses of micafungin were generally well tolerated in neonates and infants and achieved pharmacokinetic profiles predictive of an effect.

Reverse-phase high-performance liquid chromatography for the simultaneous determination of sildenafil and N-desmethyl sildenafil in plasma of children.

Sildenafil is a selective inhibitor of cGMP-specific type 5 phosphodiesterase used for the treatment of pulmonary arterial hypertension (PAH) in the adults. In pediatrics, PAH treatment options include the off-label use of sildenafil. Sildenafil is metabolized in the liver by cytocrome P450 into its active metabolite, N-desmethyl sildenafil. The determination of plasma levels of sildenafil and N-desmethyl sildenafil could be useful for therapy optimization and pharmacokinetic studies. We have developed and validated a method for the quantification of sildenafil and its metabolite in plasma of children by rapid extraction, using high-performance liquid chromatography with ultraviolet detection. The calibration range was fitted at least square model (r2 ≥ 0.999), with an accuracy and an intra- and inter-day relative standard deviation <15% for both analytes. The mean recovery was 102.5% for sildenafil and 101.8% for N-desmethyl sildenafil. This simple method could be successfully used in children with PAH under treatment with sildenafil.

Simultaneous post-neurosurgical ventriculitis and bacteraemia by two different strains of KPC-producing K. pneumoniae successfully treated with meropenem/vaborbactam and high dose of fosfomycin.

OBJECTIVE: A case of post-neurosurgical ventriculitis caused by a KPC-producing Klebsiella pneumoniae (KPC-Kp) with a ceftazidime/avibactam-resistant, meropenem-susceptible phenotype is reported. METHODS AND RESULTS: The patient had a concomitant bloodstream infection with a wild-type KPC-Kp with a ceftazidime/avibactam-susceptible, meropenem-resistant phenotype. Prolonged treatment with intravenous fosfomycin and meropenem/vaborbactam achieved clinical success. Therapeutic drug monitoring performed during the first days of treatment showed for the first time that vaborbactam efficiently penetrates cerebrospinal fluid. In contrast, meropenem was undetectable in cerebrospinal fluid at each sampling, suggesting that additional doses of meropenem may be required to appropriately prescribe meropenem/vaborbactam for central nervous system infections. Plasma and cerebrospinal fluid levels of fosfomycin were adequate, confirming the potential of this agent possibly even in the fight against multidrug-resistant organisms. CONCLUSIONS: This case highlights the need for therapeutic drug monitoring as a crucial tool for optimizing treatment in complicated cases where the pharmacokinetic behaviour of antibiotics is difficult to predict.

Father-to-daughter transmission in late-onset OTC deficiency: an underestimated mechanism of inheritance of an X-linked disease.

BACKGROUND: Ornithine Transcarbamylase Deficiency (OTCD) is an X-linked urea cycle disorder characterized by acute hyperammonemic episodes. Hemizygous males are usually affected by a severe/fatal neonatal-onset form or, less frequently, by a late-onset form with milder disease course, depending on the residual enzymatic activity. Hyperammonemia can occur any time during life and patients could remain non- or mis-diagnosed due to unspecific symptoms. In heterozygous females, clinical presentation varies based on the extent of X chromosome inactivation. Maternal transmission in X-linked disease is the rule, but in late-onset OTCD, due to the milder phenotype of affected males, paternal transmission to the females is possible. So far, father-to-daughter transmission of OTCD has been reported only in 4 Japanese families. RESULTS: We identified in 2 Caucasian families, paternal transmission of late-onset OTCD with severe/fatal outcome in affected males and 1 heterozygous female. Furthermore, we have reassessed the pedigrees of other published reports in 7 additional families with evidence of father-to-daughter inheritance of OTCD, identifying and listing the family members for which this transmission occurred. CONCLUSIONS: Our study highlights how the diagnosis and pedigree analysis of late-onset OTCD may represent a real challenge for clinicians. Therefore, the occurrence of paternal transmission in OTCD should not be underestimated, due to the relevant implications for disease inheritance and risk of recurrence.

A New and Rapid LC-MS/MS Method for the Determination of Cysteamine Plasma Levels in Cystinosis Patients.

Cystinosis is a rare lysosomal storage disorder caused by autosomal recessive mutations in the CTNS gene that encodes for the cystine transporter cystinosin, which is expressed on the lysosomal membrane mediating the efflux of cystine. Cysteamine bitartrate is a cystine-depleting aminothiol agent approved for the treatment of cystinosis in children and adults. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of cysteamine levels in plasma samples. This LC-MS/MS method was validated according to the European Medicines Agency (EMA)'s guidelines for bioanalytical method validation. An ultra-performance liquid chromatograph (UPLC) coupled with a 6470 mass spectrometry system was used for cysteamine determination. Our validated method was applied to plasma samples from n = 8 cystinosis patients (median, interquartile range (IQR) = 20.5, 8.5-26.0 years). The samples were collected before cysteamine oral administration (pre-dose) and 1 h after (post-dose). Our bioanalytical method fulfilled the regulatory guidelines for method validation. The cysteamine plasma levels in pre-dose samples were 2.57 and 1.50-3.31 µM (median and IQR, respectively), whereas the post-dose samples reported a cysteamine median concentration of 28.00 µM (IQR: 17.60-36.61). Our method allows the rapid determination of cysteamine plasma levels. This method was successfully used in cystinosis patients and, therefore, could be a useful tool for the evaluation of therapy adherence and for future pharmacokinetic (PK) studies involving a higher number of subjects.

Utilization of volumetric absorptive microsampling and dried plasma spot for quantification of anti-fungal triazole agents in pediatric patients by using liquid chromatography-tandem mass spectrometry.

BACKGROUND: Recently, increasing attention has been paid to the use of microsampling techniques for therapeutic drug monitoring (TDM) in neonatal and pediatric populations. Volumetric Absorptive Microsampling (VAMS) has been introduced in the market under the name Mitra® (Neoteryx). These devices consist of porous absorbent tips that allow collection of fixed blood volumes (10-30 µL) to overcome the DBS-related hematocrit effect. Here, the authors analyzed the concentrations of triazole agents (voriconazole, posaconazole, and isavuconazole) in VAMS and dried plasma spot (DPS) samples. METHODS: Fifty whole blood samples were obtained from pediatric patients subjected to systemic anti-fungal therapy. VAMS were collected by dipping the tip into whole blood before centrifugation for plasma recovery. Then, 30 µL of plasma was carefully spotted on filter paper to obtain DPS. Anti-fungal concentrations were measured using a validated LC-MS/MS kit (MassTox® Antimycotic Drugs/EXTENDED) provided by Chromsystems (Chromsystems Instruments & Chemicals). Drug concentrations in VAMS and DPS samples were compared to those in fresh plasma using Passing-Bablok and Bland-Altman tests. RESULTS: Plasma concentrations of voriconazole, posaconazole, and isavuconazole were positively and significantly correlated with those obtained in VAMS and DPS samples (Spearman r range, 0.82-0.94, p < 0.001). Data were further analyzed using the Bland-Altman test, which showed a % mean difference compared to fresh plasma of -15.06-10.98 (range). The stability of both VAMS and DPS was ensured for at least 14 d at room temperature. CONCLUSIONS: These results demonstrate that VAMS and DPS can be used for the TDM of anti-fungal agents. Owing to their stability, both sampling devices can be easily stored and shipped, without the need for refrigeration, to TDM laboratories that facilitate remote TDM applications. Finally, VAMS could be particularly suitable for pediatric and neonatal patients because they allow the collection of a few microliters of blood, thus improving ethical and compliance limitations.

Plasma and Cerebrospinal Fluid Concentrations of Micafungin Administered at High Doses in Critically Ill Infants with Systemic Candidiasis: A Pooled Analysis of Two Studies.

Background: Neonates may require higher doses of micafungin than adults to reach the therapeutic effect for increased plasma clearance. Only poor and inconclusive data are available still now to support this hypothesis, especially with regard to central nervous system micafungin concentrations. To assess the pharmacokinetics of increased doses (8 to 15 mg/kg/day) of micafungin in preterm and term neonates with invasive candidiasis and to complete previously presented results, we analyzed the pharmacokinetic data on a total of 53 newborns treated with micafungin, whereby 3 of them had Candida meningitis and hydrocephalus. Methods: Fifty-three neonates with systemic candidiasis, three of them with meningitis, were treated for at least 14 days with intravenous micafungin (Mycamine®) at a dosage ranging from 8 to 15 mg/kg/day. Plasma and cerebrospinal fluid (CSF) concentrations of micafungin were measured before the drug administration and at 1, 2, and 8 h after the end of the infusion using high-performance liquid chromatography (HPLC). Systemic exposure was assessed according to AUC0-24, plasma clearance (CL), and half-life measured in 52/53 patients, divided by chronological age. Results and conclusions: The mean micafungin clearance is higher in neonates than in older infants (0.036 L/h/kg before 28 days of life versus 0.028 L/h/kg after 120 days). The drug half-life is shorter in neonates than in older patients (13.5 h before 28 days of life versus 14.4 h after 120 days). With doses ranging between 8 and 15 mg/kg/day, micafungin crosses the blood-brain barrier reaching therapeutic levels in CSF.

The Use of Cefiderocol as Salvage Therapy in an Infant Receiving ECMO and Continuous Renal Replacement Therapy.

BACKGROUND: Infections caused by antimicrobial-resistant (AMR) pathogens are increasing worldwide, representing a serious global public health issue with high morbidity and mortality rates The treatment of Pseudomonas aeruginosa (PA) infections has become a significant challenge due to its ability to develop resistance to many of the currently available antibiotics, especially in intensive care unit (ICU) settings. Among the very few therapeutic lines available against extensively drug-resistant (XDR)-PA and/or with difficult-to-treat resistance (DTR)-PA, cefiderocol is an injectable siderophore cephalosporin not licensed for use in pediatric patients. There are only a few case reports and two ongoing trials describing the administration of this cephalosporin in infants. CASE PRESENTATION: This report describes the case of a critically ill 8-month-old girl affected by ventilator-associated pneumonia (VAP) infection complicated by bloodstream infection (BSI) sustained by VIM-producing PA. She was treated with cefiderocol as a salvage therapy during ECMO and CRRT support. CONCLUSIONS: In healthcare settings, treating multidrug-resistant, Gram-negative bacteria poses a serious challenge, especially in pediatric patients. Our findings suggest that cefiderocol can be considered as an off-label rescue therapy in selected pediatric cases.

Evaluation of the efficacy of cystinosin supplementation through CTNS mRNA delivery in experimental models for cystinosis.

Messenger RNA (mRNA) therapies are emerging in different disease areas, but have not yet reached the kidney field. Our aim was to study the feasibility to treat the genetic defect in cystinosis using synthetic mRNA in cell models and ctns-/- zebrafish embryos. Cystinosis is a prototype lysosomal storage disorder caused by mutations in the CTNS gene, encoding the lysosomal cystine-H+ symporter cystinosin, and leading to cystine accumulation in all cells of the body. The kidneys are the first and the most severely affected organs, presenting glomerular and proximal tubular dysfunction, progressing to end-stage kidney failure. The current therapeutic standard cysteamine, reduces cystine levels, but has many side effects and does not restore kidney function. Here, we show that synthetic mRNA can restore lysosomal cystinosin expression following lipofection into CTNS-/- kidney cells and injection into ctns-/- zebrafish. A single CTNS mRNA administration decreases cellular cystine accumulation for up to 14 days in vitro. In the ctns-/- zebrafish, CTNS mRNA therapy improves proximal tubular reabsorption, reduces proteinuria, and restores brush border expression of the multi-ligand receptor megalin. Therefore, this proof-of-principle study takes the first steps in establishing an mRNA-based therapy to restore cystinosin expression, resulting in cystine reduction in vitro and in the ctns-/- larvae, and restoration of the zebrafish pronephros function.

Impact of Continuous Kidney Replacement Therapy and Hemoadsorption with CytoSorb on Antimicrobial Drug Removal in Critically Ill Children with Septic Shock: A Single-Center Prospective Study on a Pediatric Cohort.

Background: Extracorporeal therapies (ET) are increasingly used in pediatric settings as adjuvant therapeutic strategies for overwhelming inflammatory conditions. Although these treatments seem to be effective for removing inflammatory mediators, their influence on antimicrobials pharmacokinetic should not be neglected. Methods: A prospective observational study of children admitted to the pediatric intensive care unit (PICU) with a diagnosis of sepsis/septic shock. All critically ill children received hemoadsorption treatment with CytoSorb (CS) in combination with CKRT. Therapeutic drug monitoring has been performed on 10 critically ill children, testing four antimicrobial molecules: meropenem, ceftazidime, amikacin and levofloxacin. In order to evaluate the total and isolated CKRT and CS contributions to antibiotic removal, blood samples at each circuit point (post-hemofilter, post-CS and in the effluent line) were performed. Therefore, the clearance and mass Removal (MR) of the hemofilter and CS were calculated. Results: Our preliminary report describes a different impact of CS on these target drugs removal: CS clearance was low for amikacine (6-12%), moderate for ceftazidime (43%) and moderate to high for levofloxacine (52-72%). Higher MR and clearance were observed with CKRT compared to CS. To the best of our knowledge, this is the first report regarding pharmacokinetic dynamics in critically ill children treated with CKRT and CS for septic shock.