CYP2C9, CYP3A and CYP2C19 metabolize Δ9-tetrahydrocannabinol to multiple metabolites but metabolism is affected by human liver fatty acid binding protein (FABP1)

Δ9-tetrahydrocannabinol (THC) is the psychoactive constituent of cannabis. It is cleared predominantly via metabolism. Metabolism to 11-OH-THC by cytochrome P450 (CYP) 2C9 has been proposed as the main clearance pathway of THC, with the estimated fraction metabolized (fm) about 70%. The remaining clearance pathways are not well established, and it is unknown how THC is eliminated in individuals with reduced CYP2C9 activity. The goal of this study was to systematically identify the CYP enzymes contributing to THC clearance and characterize the metabolites formed. Further, this study aimed to characterize the impact of liver fatty acid binding protein (FABP1) on THC metabolism by human CYPs. THC was metabolized to at least four different metabolites including 11-OH-THC in human liver microsomes (HLMs) and with recombinant CYPs. 11-OH-THC was formed by recombinant CYP2C9 (Km,u = 0.77 nM, kcat = 12 min-1) and by recombinant CYP2C19 (Km,u = 2.2 nM, kcat = 14 min-1). The other three major metabolites were likely hydroxylations in the cyclohexenyl ring and were formed mainly by recombinant CYP3A4/5 (Km,u > 10 nM). HLM experiments confirmed the contributions of CYP2C9, CYP2C19 and CYP3A to THC metabolism. The presence of FABP1 and THC binding to FABP1 altered THC metabolism by recombinant CYPs and HLMs in an enzyme and metabolite specific manner. This suggests that FABP1 may interact with CYP enzymes and alter the fm by CYPs towards THC metabolism. In conclusion, this study is the first to systematically establish the metabolic profile of THC by human CYPs and characterize how FABP1 binding alters CYP mediated THC metabolism.

in children in low- and middle-income countries

The prevalence of Campylobacter infection is generally high among children in low- and middle-income countries (LMIC), but the dynamics of its acquisition and clearance are understudied. We aim to quantify this process among children under two years old in eight LMIC using a statistical modeling approach, leveraging enzyme-immunoassay-based Campylobacter genus data and quantitative-PCR-based Campylobacter jejuni/coli data from the MAL-ED study. We developed a Markov model to compare the dynamics of acquisition and clearance of Campylobacter across countries and to explore the effect of antibiotic usage on Campylobacter clearance. Clearance rates were generally higher than acquisition rates, but their magnitude and temporal pattern varied across countries. For C. jejuni/coli, clearance was faster than acquisition throughout the two years at all sites. For Campylobacter spp., the acquisition rate either exceeded or stayed very close to the clearance rate after the first half year in Bangladesh, Pakistan and Tanzania, leading to high prevalence. Bangladesh had the shortest (28 and 57 days) while Brazil had the longest (328 and 306 days) mean times from last clearance to acquisition for Campylobacter spp. and C. jejuni/coli, respectively. South Africa had the shortest (10 and 8 days) while Tanzania had the longest (53 and 41 days) mean times to clearance for Campylobacter spp. and C. jejuni/col, respectively. The use of Macrolide accelerated clearance of C. jejuni/coli in Bangladesh and Peru and of Campylobacter spp. in Bangladesh and Pakistan. Fluoroquinolone showed statistically meaningful effects only in Bangladesh but for both Campylobacter groups. Higher prevalence of Campylobacter infection was mainly driven by a high acquisition rate that was close to or surpassing the clearance rate. Acquisition rate usually peaked in 11-17 months of age, indicating the importance of targeting the first year of life for effective interventions to reduce exposures.

Brain clearance of protein aggregates: a close-up on astrocytes

Protein misfolding and accumulation defines a prevailing feature of many neurodegenerative disorders, finally resulting in the formation of toxic intra- and extracellular aggregates. Intracellular aggregates can enter the extracellular space and be subsequently transferred among different cell types, thus spreading between connected brain districts.Although microglia perform a predominant role in the removal of extracellular aggregated proteins, mounting evidence suggests that astrocytes actively contribute to the clearing process. However, the molecular mechanisms used by astrocytes to remove misfolded proteins are still largely unknown.Here we first provide a brief overview of the progressive transition from soluble monomers to insoluble fibrils that characterizes amyloid proteins, referring to α-Synuclein and Tau as archetypical examples. We then highlight the mechanisms at the basis of astrocyte-mediated clearance with a focus on their potential ability to recognize, collect, internalize and digest extracellular protein aggregates. Finally, we explore the potential of targeting astrocyte-mediated clearance as a future therapeutic approach for the treatment of neurodegenerative disorders characterized by protein misfolding and accumulation.

Effects of DHA (omega-3 fatty acid) and estradiol on amyloid β-peptide regulation in the brain

In the early stages of sporadic Alzheimer's disease (SAD), there is a strong correlation between memory impairment and cortical levels of soluble amyloid-β peptide oligomers (Aβ). It has become clear that Aβ disrupt glutamatergic synaptic function, which can in turn lead to the characteristic cognitive deficits of SAD, but the actual pathways are still not well understood. This opinion article describes the pathogenic mechanisms underlying cerebral amyloidosis. These mechanisms are dependent on the amyloid precursor protein and concern the synthesis of Aβ peptides with competition between the non-amyloidogenic pathway and the amyloidogenic pathway (i.e. a competition between the ADAM10 and BACE1 enzymes), on the one hand, and the various processes of Aβ residue clearance, on the other hand. This clearance mobilizes both endopeptidases (NEP, and IDE) and removal transporters across the blood-brain barrier (LRP1, ABCB1, and RAGE). Lipidated ApoE also plays a major role in all processes. The disturbance of these pathways induces an accumulation of Aβ. The description of the mechanisms reveals two key molecules in particular: (i) free estradiol, which has genomic and non-genomic action, and (ii) free DHA as a preferential ligand of PPARα-RXRα and PPARɣ-RXRα heterodimers. DHA and free estradiol are also self-regulating, and act in synergy. When a certain level of chronic DHA and free estradiol deficiency is reached, a permanent imbalance is established in the central nervous system. The consequences of these deficits are revealed in particular by the presence of Aβ peptide deposits, as well as other markers of the etiology of SAD.

Evaluation of peritoneal dialysis prescriptions in uremic rats

BACKGROUND

Patients with end-stage kidney disease (ESKD) require dialysis or transplantation for their survival. There are few experimental animal models mimicking the human situation in which the animals are dependent on dialysis for their survival. We developed a peritoneal dialysis (PD) system for rats to enable long-term treatment under controlled conditions.

METHOD

Rats were chemically nephrectomised using orellanine to render them uremic. Two studies were performed, the first with highly uremic rats on PD for 5 days, and the other with moderately uremic rats on PD for 21 days. Blood and dialysate samples were collected repeatedly from the first study and solute concentrations analysed. Based on these values, dialysis parameters were calculated together with generation rates allowing for kinetic modelling of the effects of PD. In the second study, the general conditions of the rats were evaluated during a longer dialysis period.

RESULTS

For rats with estimated glomerular filtration rate (GFR) 5-10% of normal (moderately uremic rats), five daily PD cycles kept the rats in good condition for 3 weeks. For highly uremic rats (GFR below 3% of normal), more extensive dialysis is needed to maintain homeostasis and our simulations show that a six daily and four nightly PD cycles should be needed to keep the rats in good condition.

CONCLUSION

In conclusion, the PD system described in this study can be used for long-term studies of PD on uremic dialysis-dependent rats mimicking the human setting. To maintain whole body homeostasis of highly uremic rats, intense PD is needed during both day and night.

Searching for a "Window of Opportunity" in the Treatment of Vulvar Lichen Sclerosus: Evidence for Therapeutic Benefits of an Early Corticosteroid Treatment

INTRODUCTION

Vulvar lichen sclerosus (VLS) is characterized by progressive anatomical changes which become increasingly severe and irreversible. The objective of this study was to investigate if a "window of opportunity" exists in VLS, i.e., to assess if an early treatment may prevent disease progression and facilitate clearance of symptoms and/or signs.

METHODS

This retrospective, cohort study included VLS patients treated for the first time with a topical corticosteroid, namely with mometasone furoate 0.1% ointment, for 12 weeks (2016-2021). Scoring of subjective symptoms (global subjective score, GSS, and dyspareunia) and clinical features (global objective score [GOS] and sclerosis-scarring-atrophy) was performed at baseline (T0) and at the control visit (T1). We assessed if the achievement of clearance in GSS, GOS, sclerosis-scarring-atrophy, or dyspareunia depended on the time elapsed between VLS onset and treatment initiation.

RESULTS

Among the 168 patients (59.2 ± 13.2 years) included, the median time between VLS onset and first treatment was 14.0 months. At T1, 48.8% of patients achieved clearance of GSS, 28% of GOS and 11.9% of both GSS and GOS, 57.9% of dyspareunia, and 19.2% of sclerosis-scarring-atrophy. The logistic regression model showed that each 10-month increase in treatment initiation adversely affected the clearance of GSS while starting treatment within 6 months of disease onset was significantly associated with clearance of GOS and sclerosis-scarring-atrophy.

CONCLUSION

Early treatment is crucial in determining a complete healing of VLS-related symptoms and signs, especially of tissue sclerosis-scarring-atrophy, which appear poorly responsive, or even unresponsive, after the earliest stages of the disease. Thus our findings provide evidence for a "window of opportunity" in VLS treatment.

Comparison Pharmacokinetic Dosing Tools in Hemophilia A Children

Prophylaxis is the gold standard for the management of hemophilia A patients. It has been shown that prophylaxis regulated with pharmacokinetic (PK) data reduces frequency of bleeding and cost of treatment. To determine the best prophylaxis regimen, PK dosing tools using the Bayesian method have been developed. We aimed to compare two PK dosing tools. Blood samples were drawn before, 4, 24, and 48 h after FVIII infusions from patients with severe hemophilia A and inhibitor negative. FVIII levels were measured by PTT-based one-stage assay method. PK parameters obtained using WAPPS and myPKFiT, which are web-accessible PK dosing tools using Bayesian algorithm, and daily prophylaxis dose estimated by the programs were compared. Forty-two hemophilia A patients [median age 13 years (IQR 8.9-16.4)] included in the study. There was no difference between the daily dose of FVIII given for prophylaxis and the dose recommended by the myPKFiT for the 1% trough level; whereas, a significant difference was found with the WAPPS. The half-lives of FVIII did not differ between the two dosing tools; however, significant differences were found in the estimated dose, clearances, and times to 1% trough level. There was no significant difference between PK data of patients who received Advate® and those who received non-Advate® factor concentrates. Choice of PK dosing tool can affect recommended FVIII dose. However, target trough levels should be individualized according to bleeding phenotype and daily activity of patient.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12288-023-01671-0.

Criteria-based return to sport testing after open Latarjet reveals residual deficits and can be utilized for sports clearance with excellent outcomes at mean 3.6 year follow-up: A small case series of competitive athletes

OBJECTIVE

The purpose of this study was to assess the use of a criteria-based return to sport (CBRTS) test to evaluate readiness for return to play (RTP) in competitive athletes that underwent open Latarjet.

DESIGN

Retrospective case series.

METHODS

Ten competitive athletes (mean age 19.9 years) treated with open Latarjet for recurrent glenohumeral instability underwent CBRTS testing at a mean of 5.3 months postoperatively. Testing consisted of four components: 1. isometric strength, 2. isokinetic strength, 3. endurance, and 4. function. Patients failing 0 or 1 component of the test were cleared to RTP. Patients failing multiple components underwent additional deficit-based rehabilitation.

RESULTS

Of the 10 patients that tested, 4 passed their overall CBRTS test and were cleared to RTP. The remaining 6 patients failed the overall CBRTS test. Seven patients (70%) failed at least one section of the strength testing, two patients (20%) failed endurance testing, and two patients (20%) failed functional testing. At final follow-up (mean 3.6 years), 1 patient had recurrent instability (10%) and 9 patients returned to play (90%).

CONCLUSIONS

CBRTS testing may be clinically useful for return to play clearance decisions after open Latarjet procedure, as it can reveal deficits that may not be identified with time-based clearance alone.

Decoupling FcRn and tumor contributions to elevated immune checkpoint inhibitor clearance in cancer cachexia

High baseline clearance of immune checkpoint inhibitors (ICIs), independent of dose or systemic exposure, is associated with cachexia and poor outcomes in cancer patients. Mechanisms linking ICI clearance, cachexia and ICI therapy failure are unknown. Here, we evaluate in four murine models and across multiple antibodies whether altered baseline catabolic clearance of administered antibody requires a tumor and/or cachexia and whether medical reversal of cachexia phenotype can alleviate altered clearance. Key findings include mild cachexia phenotype and lack of elevated pembrolizumab clearance in the MC38 tumor-bearing model. We also observed severe cachexia and decreased, instead of increased, baseline pembrolizumab clearance in the tumor-free cisplatin-induced cachexia model. Liver Fcgrt expression correlated with altered baseline catabolic clearance, though elevated clearance was still observed with antibodies having no (human IgA) or reduced (human H310Q IgG1) FcRn binding. We conclude cachexia phenotype coincides with altered antibody clearance, though tumor presence is neither sufficient nor necessary for altered clearance in immunocompetent mice. Magnitude and direction of clearance alteration correlated with hepatic Fcgrt, suggesting changes in FcRn expression and/or recycling function may be partially responsible, though factors beyond FcRn also contribute to altered clearance in cachexia.

Notes on the Use of Kirchhoff's Laws in Pharmacokinetics

Recent publications by Benet and coworkers, Korzekwa and Nagar, and Rowland et al. signal disagreement regarding the use of Kirchhoff's laws in combining pharmacokinetic parameters, especially clearances and rate constants. Here, it is pointed out that Kirchhoff's laws as applied to pharmacokinetics simply assert that concentrations are well defined and that molar or mass balances hold. The real issue is how to combine parameters for clearance processes in sequence, which may be reversible, irreversible, or even active in either or both directions. It is also demonstrated that Kirchhoff's laws cannot be used to resolve contradictory results observed in liver transport and clearance. Finally, a simple argument is provided relating nonlinear clearance to apparently anomalous bioavailability observations.

Sampling from Extracorporeal Circuit: A Step Forward for Dose Monitoring in Continuous Renal Replacement Therapy

INTRODUCTION

Continuous renal replacement therapies (CRRTs) require constant monitoring and periodic treatment readjustments, being applied to highly complex patients, with rapidly changing clinical needs. To promote precision medicine in the field of renal replacement therapy and encourage dynamic prescription, the Acute Dialysis Quality Initiative (ADQI) recommends periodically measuring the solutes extracorporeal clearance with the aim of assessing the current treatment delivery and the gap from the therapeutic prescription (often intended as effluent dose). To perform this procedure, it is therefore necessary to obtain blood and effluent samples from the extracorporeal circuit to measure the concentrations of a target solute (usually represented by urea) in prefilter, postfilter, and effluent lines. However, samples must be collected simultaneously from the extracorporeal circuit ports, with the same suction flow at an unknown rate.

METHODS

The proposed study takes the first step toward identifying the technical factors that should be considered in determining the optimal suction rate to collect samples from the extracorporeal circuit to measure the extracorporeal clearance for a specific solute.

RESULTS

The results obtained identify the low suction rate (i.e., 1 mL/min) as an ideal parameter for an adequate sampling method. Low velocities do not perturb the external circulation system and ensure stability prevailing pressures in the circuit. Higher velocities can be performed only with blood flows above 120 mL/min preferably in conditions of appropriate filtration fraction.

DISCUSSION/CONCLUSIONS

The specific value of aspiration flow rate must be proportioned to the prescription of CRRT treatments set by the clinician.

Outcome and associated factors of high-risk human papillomavirus infection without cervical lesions

OBJECTIVE

To study the outcome of human papillomavirus (HPV) infection in women with cervical pathology results of non-cervical intraepithelial neoplasia (CIN) or cervical cancer and positive high-risk HPV test, as well as analyze the associated risk factors affecting the outcome of infection.

METHODS

To investigate the outcome of high-risk (HR)-HPV infection in the female genital tract and analyze the associated risk factors affecting their outcome, a total of 196 women with positive HR-HPV test results and non-CIN or cervical cancer cervical pathology results were selected for follow-up at the Cervical Disease Clinic of the Obstetrics and Gynecology Hospital, Zhejiang University School of Medicine from January 2017 to March 2020. The follow-up interval was every 6 months, and both cervical cytology (TCT) and HR-HPV testing were performed at each follow-up visit. If the cervical cytology results were normal upon recheck and the HR-HPV test was negative, the woman was considered to be cleared of the HPV infection and was entered into the routine cervical screening population. When the repeat HR-HPV test remained positive after 6 months, the woman was defined as having a persistent HR-HPV infection. If HR-HPV persisted but the TCT results were normal, follow-up was continued. If HR-HPV persisted and the TCT results were abnormal, a colposcopy-guided biopsy was performed immediately. In this situation, if the histological results were still non-CIN or cervical cancer, the follow-up was continued. If the histological results confirmed the development of CIN or invasive cancer, then enter another study follow-up to further track its development and outcome, and the woman commenced the treatment process. The HPV infection clearance time was analyzed by the Kaplan-Meier method, and the comparison of the HPV clearance rate and infection clearance time between each of the different groups was performed using aχ2 test or Fisher's exact test, as appropriate. After the univariate analysis, several significant factors were included in the Cox model and independent risk factors were analyzed.

RESULTS

A total of 163 women were enrolled in this study. The median age was 40.0 years (22-67 years) and the median follow-up time was 11.5 months (6-31 months). The spontaneous clearance rate of HR-HPV infection was 51.5%, and the median time to viral clearance was 14.5 months. Age and the initial viral load were high risk factors affecting the spontaneous clearance of HR-HPV infection. The factors significantly associated with HPV clearance rate and time to HPV clearance consisted of menopause and full-term delivery (P < 0.05).

CONCLUSIONS

In women with normal or low-grade lesions on the cell smear, the spontaneous clearance rate of HR-HPV infection was 51.5% and the time to clearance was 14.5 months. Age and the initial viral load were independent associated factors affecting the spontaneous clearance of HR-HPV infection in the female genital tract. These findings suggest that non-young women or those with high viral loads have a higher rate of persistent HR-HPV infection. Thus, intensive screening should be recommended.

Effectiveness and safety of REBACIN as a non-invasive intervention for persistent high-risk human papillomavirus infection: A real-world prospective multicenter cohort study

BACKGROUND

We previously reported that REBACIN effectively eliminates persistent high-risk human papillomavirus (hrHPV) infection. Here, we conducted a prospective multicenter cohort study to evaluate the safety and effectiveness of REBACIN, taking into account factors such as specific hrHPV subtype and patient's age.

METHODS

According to inclusion/exclusion criteria and participant willingness, 3252 patients were divided into REBACIN group while 249 patients into control group. Patients in REBACIN group received one course treatment of intravaginal administration of REBACIN while no treatment in control group. After drug withdrawal, participants in both groups were followed up.

RESULTS

The clearance rate of persistent hrHPV infection in REBACIN group was 60.64%, compared to 20.08% in control group. Specifically, the clearance rates for single-type infection of HPV16 or HPV18 were 70.62% and 69.23%, respectively, which was higher than that of HPV52 (59.04%) or HPV58 (62.64%). In addition, the single, double, and triple/triple+ infections had a clearance rate of 65.70%, 53.31%, and 38.30%, respectively. Moreover, 1635 patients under 40 years old had a clearance rate of 65.14%, while it was 55.08% for 1447 patients over 40 years old. No serious adverse effects were found.

CONCLUSION

This study confirmed that REBACIN can effectively and safely eliminate persistent hrHPV infection, which the clearance rate of HPV16/18 is higher than that of HPV52/58, the clearance rate of single-type infection is higher than that of multiple-type infections, and the clearance rate in young patients is higher than that in elder patients, providing a guidance for REBACIN application in clearing hrHPV persistent infection in real-world settings.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry Registration Number: ChiCTR1800015617 http://www.chictr.org.cn/showproj.aspx?proj=26529 Date of Registration: 2018-04-11.

Proteasome inhibition protects blood-brain barrier P-glycoprotein and lowers Aβ brain levels in an Alzheimer's disease model

BACKGROUND

Loss of P-glycoprotein (P-gp) at the blood-brain barrier contributes to amyloid-β (Aβ) brain accumulation in Alzheimer's disease (AD). Using transgenic human amyloid precursor protein (hAPP)-overexpressing mice (Tg2576), we previously showed that Aβ triggers P-gp loss by activating the ubiquitin-proteasome pathway, which leads to P-gp degradation. Furthermore, we showed that inhibiting the ubiquitin-activating enzyme (E1) prevents P-gp loss and lowers Aβ accumulation in the brain of hAPP mice. Based on these data, we hypothesized that repurposing the FDA-approved proteasome inhibitor, bortezomib (Velcade®; BTZ), protects blood-brain barrier P-gp from degradation in hAPP mice in vivo.

METHODS

We treated hAPP mice with the proteasome inhibitor BTZ or a combination of BTZ with the P-gp inhibitor cyclosporin A (CSA) for 2 weeks. Vehicle-treated wild-type (WT) mice were used as a reference for normal P-gp protein expression and transport activity. In addition, we used the opioid receptor agonist loperamide as a P-gp substrate in tail flick assays to indirectly assess P-gp transport activity at the blood-brain barrier in vivo. We also determined P-gp protein expression by Western blotting, measured P-gp transport activity levels in isolated brain capillaries with live cell confocal imaging and assessed Aβ plasma and brain levels with ELISA.

RESULTS

We found that 2-week BTZ treatment of hAPP mice restored P-gp protein expression and transport activity in brain capillaries to levels found in WT mice. We also observed that hAPP mice displayed significant loperamide-induced central antinociception compared to WT mice indicating impaired P-gp transport activity at the blood-brain barrier of hAPP mice in vivo. Furthermore, BTZ treatment prevented loperamide-induced antinociception suggesting BTZ protected P-gp loss in hAPP mice. Further, BTZ-treated hAPP mice had lower Aβ40 and Aβ42 brain levels compared to vehicle-treated hAPP mice.

CONCLUSIONS

Our data indicate that BTZ protects P-gp from proteasomal degradation in hAPP mice, which helps to reduce Aβ brain levels. Our data suggest that the proteasome system could be exploited for a novel therapeutic strategy in AD, particularly since increasing Aβ transport across the blood-brain barrier may prove an effective treatment for patients.

In Vitro Interaction of Tetrahydrouridine with Key Human Nucleoside Transporters

NDec is a novel combination of oral decitabine and tetrahydrouridine that is currently under clinical development for the treatment of sickle cell disease (SCD). Here, we investigate the potential for the tetrahydrouridine component of NDec to act as an inhibitor or substrate of key concentrative nucleoside transporters (CNT1-3) and equilibrative nucleoside transporters (ENT1-2). Nucleoside transporter inhibition and tetrahydrouridine accumulation assays were performed using Madin-Darby canine kidney strain II (MDCKII) cells overexpressing human CNT1, CNT2, CNT3, ENT1, and ENT2 transporters. Results showed that tetrahydrouridine did not influence CNT- or ENT-mediated uridine/adenosine accumulation in MDCKII cells at the concentrations tested (25 and 250 µM). Accumulation of tetrahydrouridine in MDCKII cells was initially shown to be mediated by CNT3 and ENT2. However, while time- and concentration-dependence experiments showed active accumulation of tetrahydrouridine in CNT3-expressing cells, allowing for estimation of Km (3,140 µM) and Vmax (1,600 pmol/mg protein/min), accumulation of tetrahydrouridine was not observed in ENT2-expressing cells. Potent CNT3 inhibitors are a class of drugs not generally prescribed to patients with SCD, except in certain specific circumstances. These data suggest that NDec can be administered safely with drugs that act as substrates and inhibitors of the nucleoside transporters included in this study.

Effect of massive ascites on ramucirumab pharmacokinetics in patients with gastrointestinal cancers: a population pharmacokinetic analysis

PURPOSE

Considerable amounts of injected immunoglobulin G-based therapeutic monoclonal antibodies, such as ramucirumab, are distributed into ascites. This study aimed to examine the effect of massive ascites on ramucirumab pharmacokinetics in patients with gastrointestinal cancers.

METHODS

Population pharmacokinetic analysis of ramucirumab was performed using data on serum ramucirumab concentrations of 52 patients with gastrointestinal cancers, including 8 patients with massive ascites. The Bayesian method using the final population pharmacokinetic model was utilized to estimate trough ramucirumab concentrations after the first dose and at steady state.

RESULTS

Population pharmacokinetic analysis revealed that massive ascites as well as body weight were influencing factors for ramucirumab clearance. The estimated ramucirumab clearance was significantly higher in patients with massive ascites than in those with no/mild ascites (0.020 ± 0.004 versus 0.013 ± 0.004 L/h, P < 0.001). The estimated trough ramucirumab concentrations were significantly lower in patients with massive ascites than in those with no/mild ascites after the first dose (26.4 ± 6.8 versus 36.1 ± 7.1 μg/mL, P < 0.001) and at steady state (41.4 ± 16.3 versus 65.9 ± 18.0 μg/mL, P < 0.001).

CONCLUSION

In the present study, the presence of massive ascites affected the pharmacokinetics of ramucirumab in patients with gastrointestinal cancers. Our results suggest that dose optimization of ramucirumab may be necessary in patients with massive ascites due to higher ramucirumab clearance.

Influence of conversion factors on the radioactivity evaluation of clearance objects consisting of several materials

Control panel waste generated from nuclear power plants is a new candidate for clearance under Japan's amended regulations. In the radioactivity evaluation, a simplified conversion factor for density and source location conditions has been used, assuming that it applies to unmixed materials such as metals. To investigate its applicability to control panels consisting of metal and organic materials, we examined the application of the conventional conversion factor by simulations of radiation measurements for a point source in a control panel.

Biosafety of mesoporous silica nanoparticles; towards clinical translation

Mesoporous silica nanoparticles (MSNs) have attracted the attention of chemists, who have developed numerous systems for the encapsulation of a plethora of molecules, allowing the use of mesoporous silica nanoparticles for biomedical applications. MSNs have been extensively studied for their use in nanomedicine, in applications such as drug delivery, diagnosis, and bioimaging, demonstrating significant in vivo efficacy in different preclinical models. Nevertheless, for the transition of MSNs into clinical trials, it is imperative to understand the characteristics that make MSNs effective and safe. The biosafety properties of MSNs in vivo are greatly influenced by their physicochemical characteristics such as particle shape, size, surface modification, and silica framework. In this review, we compile the most relevant and recent progress in the literature up to the present by analyzing the contributions on biodistribution, biodegradability, and clearance of MSNs. Furthermore, the ongoing clinical trials and the potential challenges related to the administration of silica materials for advanced therapeutics are discussed. This approach aims to provide a solid overview of the state-of-the-art in this field and to encourage the translation of MSNs to the clinic.

Standardization of Nomenclature for the Mechanisms and Materials Utilized for Extracorporeal Blood Purification

In order to develop a standardized nomenclature for the mechanisms and materials utilized during extracorporeal blood purification, a consensus expert conference was convened in November 2022. Standardized nomenclature serves as a common language for reporting research findings, new device development, and education. It is also critically important to support patient safety, allow comparisons between techniques, materials, and devices, and be essential for defining and naming innovative technologies and classifying devices for regulatory approval. The multidisciplinary conference developed detailed descriptions of the performance characteristics of devices (membranes, filters, and sorbents), solute and fluid transport mechanisms, flow parameters, and methods of treatment evaluation. In addition, nomenclature for adsorptive blood purification techniques was proposed. This report summarizes these activities and highlights the need for standardization of nomenclature in the future to harmonize research, education, and innovation in extracorporeal blood purification therapies.

Characterization of a human placental clearance system to regulate serotonin levels in the fetoplacental unit

BACKGROUND

Serotonin (5-HT) is a biogenic monoamine with diverse functions in multiple human organs and tissues. During pregnancy, tightly regulated levels of 5-HT in the fetoplacental unit are critical for proper placental functions, fetal development, and programming. Despite being a non-neuronal organ, the placenta expresses a suite of homeostatic proteins, membrane transporters and metabolizing enzymes, to regulate monoamine levels. We hypothesized that placental 5-HT clearance is important for maintaining 5-HT levels in the fetoplacental unit. We therefore investigated placental 5-HT uptake from the umbilical circulation at physiological and supraphysiological levels as well as placental metabolism of 5-HT to 5-hydroxyindoleacetic acid (5-HIAA) and 5-HIAA efflux from trophoblast cells.

METHODS

We employed a systematic approach using advanced organ-, tissue-, and cellular-level models of the human placenta to investigate the transport and metabolism of 5-HT in the fetoplacental unit. Human placentas from uncomplicated term pregnancies were used for perfusion studies, culturing explants, and isolating primary trophoblast cells.

RESULTS

Using the dually perfused placenta, we observed a high and concentration-dependent placental extraction of 5-HT from the fetal circulation. Subsequently, within the placenta, 5-HT was metabolized to 5-hydroxyindoleacetic acid (5-HIAA), which was then unidirectionally excreted to the maternal circulation. In the explant cultures and primary trophoblast cells, we show concentration- and inhibitor-dependent 5-HT uptake and metabolism and subsequent 5-HIAA release into the media. Droplet digital PCR revealed that the dominant gene in all models was MAO-A, supporting the crucial role of 5-HT metabolism in placental 5-HT clearance.

CONCLUSIONS

Taken together, we present transcriptional and functional evidence that the human placenta has an efficient 5-HT clearance system involving (1) removal of 5-HT from the fetal circulation by OCT3, (2) metabolism to 5-HIAA by MAO-A, and (3) selective 5-HIAA excretion to the maternal circulation via the MRP2 transporter. This synchronized mechanism is critical for regulating 5-HT in the fetoplacental unit; however, it can be compromised by external insults such as antidepressant drugs.

Silk fibroin-based embolic agent for transhepatic artery embolization with multiple therapeutic potentials

BACKGROUND

The excellent physicochemical and biomedical properties make silk fibroin (SF) suitable for the development of biomedical materials. In this research, the silk fibroin microspheres (SFMS) were customized in two size ranges, and then carried gold nanoparticles or doxorubicin to evaluate the performance of drug loading and releasing. Embolization efficiency was evaluated in rat caudal artery and rabbit auricular artery, and the in vivo distribution of iodinated SFMS (125I/131I-SFMS) after embolization of rat hepatic artery was dynamically recorded by SPECT. Transhepatic arterial radioembolization (TARE) with 131I-SFMS was performed on rat models with liver cancer. The whole procedure of selective internal radiation was recorded with SPECT/CT, and the therapeutic effects were evaluated with 18 F-FDG PET/CT. Lastly, the enzymatic degradation was recorded and followed with the evaluation of particle size on clearance of sub-micron silk fibroin.

RESULTS

SFMS were of smooth surface and regular shape with pervasive pores on the surface and inside the microspheres, and of suitable size range for TAE. Drug-loading functionalized SFMS with chemotherapy or radio-sensitization, and the enhanced therapeutic effects were proved in treating HUH-7 cells as lasting doxorubicin release or more lethal radiation. For artery embolization, SFMS effectively blocked the blood supply; when 131I-SFMS serving as the embolic agent, the good labeling stability and embolization performance guaranteed the favorable therapeutic effects in treating in situ liver tumor. At the 5th day post TARE with 37 MBq/3 mg 131I-SFMS per mice, tumor activity was quickly inhibited to a comparable glucose metabolism level with surrounding normal liver. More importantly, for the fragments of biodegradable SFMS, smaller sized SF (< 800 nm) metabolized in gastrointestinal tract and excreted by the urinary system, while SF (> 800 nm) entered the liver within 72 h for further metabolism.

CONCLUSION

The feasibility of SFMS as degradable TARE agent for liver cancer was primarily proved as providing multiple therapeutic potentials.

How effective are ionization state-based QSPKR models at predicting pharmacokinetic parameters in humans?

Optimizing the pharmacokinetics (PK) of a drug candidate to support oral dosing is a key challenge in drug development. PK parameters are usually estimated from the concentration-time profile following intravenous administration; however, traditional methods are time-consuming and expensive. In recent years, quantitative structure-pharmacokinetic relationship (QSPKR), an in silico tool that aims to develop a mathematical relationship between the structure of a molecule and its PK properties, has emerged as a useful alternative to experimental testing. Due to the complex nature of the various processes involved in dictating the fate of a drug, the development of adequate QSPKR models that can be used in real-world pre-screening situations has proved challenging. Given the crucial role played by a molecule's ionization state in determining its PK properties, this work aims to build predictive QSPKR models for PK parameters in humans using an ionization state-based strategy. We divide a high-quality dataset into clusters based on ionization state at physiological pH and build global and ion subset-based 'local' models for three major PK parameters: plasma clearance (CL), steady-state volume of distribution (VDss), and half-life (t1/2). We use a robust methodology developed in our lab entitled 'EigenValue ANalySis' that accounts for the stereospecificity in drug disposition and use the support vector machine algorithm for model building. Our findings suggest that categorizing compounds in accordance with ionization state does not result in improved QSPKR models. The narrow ranges in the endpoints along with redundancies in the data adversely affect the ion subset-based QSPKR models. We suggest alternative approaches such as elimination route-based models that account for drug-transporter interactions for CL and chemotype-specific QSPKR for VDss.

Clinical pharmacokinetic of cefixime: a systematic review

Cefixime is an antibiotic from the cephalosporin class used to treat various bacterial infections. The purpose of performing this review is to thoroughly evaluate the pharmacokinetic (PK) data on cefixime.Five databases were systematically searched to identify studies on the PK of cefixime.A total of 38 articles meeting the eligibility criteria were included that provide data on concentration-time profiles or PK parameters such as peak plasma and serum concentration (C_max), area under the curve (AUC), clearance (CL), and time to reach C_max (t_max). A dose-dependent increase in AUC and Cmax of cefixime was depicted in healthy volunteers. The clearance of cefixime decreased according to the degree of renal insufficiency among haemodialysis patients. A significant difference in CL was found in comparing fasted and fed states. A biphasic decline in serum concentrations of cefixime was reported when it was taken without probenecid.This review compiles all the reports on the PK of cefixime in healthy and renally impaired patients; the summarized information can be used to optimize cefixime dosing in different disease states. Moreover, cefixime has increased time above MIC value suggesting that it may be an effective treatment for infections caused by certain pathogens.

Promoting AMPK/SR-A1-mediated clearance of HMGB1 attenuates chemotherapy-induced peripheral neuropathy

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious side effect of chemotherapy with poorly understood mechanisms and few treatments. High-mobility group box 1 (HMGB1)-induced neuroinflammation is the main cause of CIPN. Here, we aimed to illustrate the role of the macrophage scavenger receptor A1 (SR-A1) in HMGB1 clearance and CIPN resolution.

METHODS

Oxaliplatin (L-OHP) was used to establish a CIPN model. Recombinant HMGB1 (rHMGB1) (his tag) was used to evaluate the phagocytosis of HMGB1 by macrophages.

RESULTS

In the clinic, HMGB1 expression and MMP-9 activity were increased in the plasma of patients with CIPN. Plasma HMGB1 expression was positively correlated with the cumulative dose of L-OHP and the visual analog scale. In vitro, engulfment and degradation of rHMGB1 increased and inflammatory factor expression decreased after AMP-activated protein kinase (AMPK) activation. Neutralizing antibodies, inhibitors, or knockout of SR-A1 abolished the effects of AMPK activation on rHMGB1 engulfment. In vivo, AMPK activation increased SR-A1 expression in the dorsal root ganglion, decreased plasma HMGB1 expression and MMP-9 activity, and attenuated CIPN, which was abolished by AMPK inhibition or SR-A1 knockout in the CIPN mice model.

CONCLUSION

Activation of the AMPK/SR-A1 axis alleviated CIPN by increasing macrophage-mediated HMGB1 engulfment and degradation. Therefore, promoting HMGB1 clearance may be a potential treatment strategy for CIPN. Video abstract.

Biokinetics of subacutely co-inhaled same size gold and silver nanoparticles

BACKGROUND

Toxicokinetics of nanomaterials, including studies on the absorption, distribution, metabolism, and elimination of nanomaterials, are essential in assessing their potential health effects. The fate of nanomaterials after inhalation exposure to multiple nanomaterials is not clearly understood.

METHODS

Male Sprague-Dawley rats were exposed to similar sizes of silver nanoparticles (AgNPs, 10.86 nm) and gold nanoparticles (AuNPs, 10.82 nm) for 28 days (6-h/day, 5-days/week for four weeks) either with separate NP inhalation exposures or with combined co-exposure in a nose-only inhalation system. Mass concentrations sampled from the breathing zone were AuNP 19.34 ± 2.55 μg/m³ and AgNP 17.38 ± 1.88 μg/m³ for separate exposure and AuNP 8.20 μg/m³ and AgNP 8.99 μg/m³ for co-exposure. Lung retention and clearance were previously determined on day 1 (6-h) of exposure (E-1) and on post-exposure days 1, 7, and 28 (PEO-1, PEO-7, and PEO-28, respectively). In addition, the fate of nanoparticles, including translocation and elimination from the lung to the major organs, were determined during the post-exposure observation period.

RESULTS

AuNP was translocated to the extrapulmonary organs, including the liver, kidney, spleen, testis, epididymis, olfactory bulb, hilar and brachial lymph nodes, and brain after subacute inhalation and showed biopersistence regardless of AuNP single exposure or AuNP + AgNP co-exposure, showing similar elimination half-time. In contrast, Ag was translocated to the tissues and rapidly eliminated from the tissues regardless of AuNP co-exposure. Ag was continually accumulated in the olfactory bulb and brain and persistent until PEO-28.

CONCLUSION

Our co-exposure study of AuNP and AgNP indicated that soluble AgNP and insoluble AuNP translocated differently, showing soluble AgNP could be dissolved into Ag ion to translocate to the extrapulmonary organs and rapidly removed from most organs except the brain and olfactory bulb. Insoluble AuNPs were continually translocated to the extrapulmonary organs, and they were not eliminated rapidly.

Physiological β-amyloid clearance by the liver and its therapeutic potential for Alzheimer's disease

Cerebral amyloid-β (Aβ) accumulation due to impaired Aβ clearance is a pivotal event in the pathogenesis of Alzheimer's disease (AD). Considerable brain-derived Aβ is cleared via transporting to the periphery. The liver is the largest organ responsible for the clearance of metabolites in the periphery. Whether the liver physiologically clears circulating Aβ and its therapeutic potential for AD remains unclear. Here, we found that about 13.9% of Aβ42 and 8.9% of Aβ40 were removed from the blood when flowing through the liver, and this capacity was decreased with Aβ receptor LRP-1 expression down-regulated in hepatocytes in the aged animals. Partial blockage of hepatic blood flow increased Aβ levels in both blood and brain interstitial fluid. The chronic decline in hepatic Aβ clearance via LRP-1 knockdown specific in hepatocytes aggravated cerebral Aβ burden and cognitive deficits, while enhancing hepatic Aβ clearance via LRP-1 overexpression attenuated cerebral Aβ deposition and cognitive impairments in APP/PS1 mice. Our findings demonstrate that the liver physiologically clears blood Aβ and regulates brain Aβ levels, suggesting that a decline of hepatic Aβ clearance during aging could be involved in AD development, and hepatic Aβ clearance is a novel therapeutic approach for AD.

A model of zinc dynamics evoked by intense stimulation at the cleft of hippocampal mossy fiber synapses

Zinc is a transition metal that is particularly abundant in the mossy fibers of the hippocampal CA3 area. Despite the large number of studies about the zinc role in mossy fibers, the action of zinc in synaptic mechanisms is only partly known. The use of computational models can be a useful tool for this study. In a previous work, a model was developed to evaluate zinc dynamics at the mossy fiber synaptic cleft, following weak stimulation, insufficient to evoke zinc entry into postsynaptic neurons. For intense stimulation, cleft zinc effluxes must be considered. Therefore, the initial model was extended to include postsynaptic zinc effluxes based on the Goldman-Hodgkin-Katz current equation combined with Hodgkin and Huxley conductance changes. These effluxes occur through different postsynaptic escape routes, namely L- and N-types voltage-dependent calcium channels and NMDA receptors. For that purpose, various stimulations were assumed to induce high concentrations of cleft free zinc, named as intense (10 μM), very intense (100 μM) and extreme (500 μM). It was observed that the main postsynaptic escape routes of cleft zinc are the L-type calcium channels, followed by the NMDA receptor channels and by N-type calcium channels. However, their relative contribution for cleft zinc clearance was relatively small and decreased for higher amounts of zinc, most likely due to the blockade action of zinc in postsynaptic receptors and channels. Therefore, it can be concluded that the larger the zinc release, the more predominant the zinc uptake process will be in the cleft zinc clearance.

An "IgG-hitchhiking" approach for rapid tumor accumulation and clearance of photosensitizers

Photodynamic therapy (PDT) has been widely used for the local treatment of a variety of cancer. To improve the therapeutic effect, delicate nanoparticles loading photosensitizers (PSs) have been designed to improve the accumulation of PSs in tumor. Different from the anti-cancer drugs for chemotherapy or immunotherapy, the delivery of PSs requires rapid tumor accumulation followed by quick elimination to reduce the potential risk of phototoxicity. However, owing to the nature of prolonged blood circulation of the nanoparticles, the conventional nanoparticulate delivery systems may decelerate the clearance of PSs. Here, we present a tumor-targeted delivery approach termed "IgG-hitchhiking" strategy through a self-assembled PSs nanostructure, according to the intrinsic binding between the photosensitizer pheophorbide A (PhA) and immunoglobulin (IgG). We utilize the intravital fluorescence microscopic imaging to uncover that the nanostructures (IgG:PhA NPs) increase the extravasation of PhA into tumor within the first hour post intravenous injection compared with free PhA, correlating with an improved efficacy of PDT. After ∼1 h post-injection, a quick decrease in the PhA amount in the tumor is observed, while the tumor IgG level is continuously increasing. The disparity of the tumor distribution between PhA and IgG allows the quick elimination of the PSs for minimized skin phototoxicity. Our results provide a direct evidence of the enhanced accumulation and elimination of the PSs in the tumor microenvironment through the "IgG-hitchhiking" approach. This strategy presents a promising tumor-targeted delivery approach for the PSs in lieu of the existing strategy for enhanced PDT with minimal toxicity in clinic.

Tissue-specific accumulation, depuration, and effects of perfluorooctanoic acid on fish: Influences of aqueous pH and sex

Perfluorooctanoic acid (PFOA) is widely distributed in nature, particularly in aquatic environments. Its bioaccumulation and toxicity in aquatic organisms can be affected by both the chemical status of PFOA in water and the physiology of the organism. However, research on the patterns of these effects is scarce. In this study, we investigated the influence of aqueous pH (pH 6, acidic; pH 7.5, neutral; pH 9, basic) and fish sex on PFOA uptake, clearance, and biochemical effects in crucian carp (C. auratus) using flow-through exposure. In the 17-d kinetic experiment, PFOA bioaccumulation adhered to a uniform first-order model in which PFOA uptake rates from water to blood and liver in acidic conditions were faster than those in other conditions, indicating possible acidic pH influence on PFOA uptake. PFOA clearance rates in these compartments of males were slower than in females, which was attributed to the notably stronger expression of Oat2 (organic anion transporter 2, responsible for reabsorption) in the kidneys of males. Similar responses were observed for peroxisome proliferation-related biomarkers at different pH levels and in different sexes. These biochemical responses were driven by the internal concentrations of PFOA. The inhibition acetylcholinesterase activity in the fish brain was closely linked to changes in P-glycoprotein content, demonstrating a protective relationship. Collectively, an aqueous pH lower than 7.5 might affect the uptake of PFOA by fish. The clearance discrepancies between the sexes highlight the importance of anion carriers for ionizable organic compounds in aquatic organisms.

Clearance of blood stream infections in patients receiving extracorporeal membrane oxygenation: a retrospective single-center cohort study

BACKGROUND

There are limited data on the treatment of blood stream infections (BSIs) in patients receiving extracorporeal membrane oxygenation (ECMO). Current guidance recommends documenting clearance only in fungal and Gram-positive BSIs. This study investigates the incidence and clinical significance of blood stream infections with positive repeat cultures (BSIPRC) in ECMO as well as clinical factors that may predict positive repeat cultures.

METHODS

All BSIs in patients receiving ECMO at Brooke Army Medical Center between September 2012 and October 2021 were included in this study. BSIPRC was defined as re-isolation of the same organism on repeat blood cultures following an initial positive blood culture.

RESULTS

A total of 60 patients developed 87 BSI (38.5 BSI per 1000 ECMO days). Of the 80 (92%) BSIs who had repeat blood cultures drawn, patients had BSIPRC in 35 (44%) of cases. Fever, leukocytosis, and vasopressor requirement on day of repeat culture were not associated with persistent positivity. There was no difference in survival to discharge for patients with BSIPRC as compared to single day BSI (58% vs. 63%, p = 0.78). 19% of patients with Gram-negative bacteremia had BSIPRC, and gram-negative bacteremia in general was associated with an 83% morality.

CONCLUSIONS

There were no clinical findings that differentiated patients with BSIPRC from those who had a single day of positivity. BSI was associated with high mortality in patients with Gram-negative bacteremia. Given high incidence of positive repeat cultures being seen in Gram-negative BSIs, repeat blood cultures have utility for all BSIs in patients receiving ECMO.

The plasma free fraction of 25-hydroxyvitamin D3 is not strongly associated with 25-hydroxyvitamin D3 clearance in kidney disease patients and controls

Circulating 25-hydroxyvitamin D [25(OH)D] concentration is used to monitor vitamin D status. Plasma protein binding may influence the 25(OH)D dose-response to vitamin D treatment through a direct relationship between the plasma unbound ("free") fraction and clearance of 25(OH)D. We previously evaluated 25(OH)D3 clearance in relation to kidney function using intravenous administration of deuterium labeled 25(OH)D3. In this follow up study, we determined the free fraction of 25(OH)D3 in plasma (i.e., percent free 25(OH)D3) and the serum concentration and haplotype of vitamin D binding protein in these participants. We hypothesized that the percent free 25(OH)D3 would be positively associated with 25(OH)D3 clearance and would mediate associations between clearance and vitamin D binding protein (GC) haplotypes. Participants were mean (SD) age 64 (10) years and included 42 individuals with normal kidney function (controls), 24 individuals with chronic kidney disease, and 19 individuals with kidney failure on hemodialysis. Free plasma 25(OH)D2 and 25(OH)D3 concentrations were quantified with a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Because there is no reference measurement procedure for free 25(OH)D, we compared the new method with a widely-used predictive equation and a commercial immunoassay. The percent free 25(OH)D3 determined by predictive equation was weakly associated with 25(OH)D3 clearance (R = 0.27; P = 0.01). However, this association was absent when percent free 25(OH)D3 was determined using LC-MS/MS-measured free and total 25(OH)D3 concentrations. Method comparison uncovered a negative bias in immunoassay-measured free 25(OH)D concentrations among participants with kidney failure, so immunoassay results were not used to evaluate the association between percent free 25(OH)D3 and clearance. GC2 haplotype carriage was associated with 25(OH)D3 clearance. Among individuals with 2 relative to no GC2 alleles, clearance was 87 (95% CI: 15-158) mL/d greater. However, in contrast with the literature, GC2 carriage was not significantly related to DBP concentration or the percent free 25(OH)D3 (either predicted or measured). In conclusion, the free fraction of 25(OH)D3 is not strongly associated with 25(OH)D3 clearance but may explain small differences in clearance according to GC haplotype.

Ultrasmall silica nanoparticles in translational biomedical research: Overview and outlook

The exemplary progress of silica nanotechnology has attracted extensive attention across a range of biomedical applications such as diagnostics and imaging, drug delivery, and therapy of cancer and other diseases. Ultrasmall silica nanoparticles (USNs) have emerged as a particularly promising class demonstrating unique properties that are especially suitable for and have shown great promise in translational and clinical biomedical research. In this review, we discuss synthetic strategies that allow precise engineering of USNs with excellent control over size and surface chemistry, functionalization, and pharmacokinetic and toxicological profiles. We summarize the current state-of-the-art in the biomedical applications of USNs with a particular focus on select clinical studies. Finally, we illustrate long-standing challenges in the translation of inorganic nanotechnology, particularly in the context of ultrasmall nanomedicines, and provide our perspectives on potential solutions and future opportunities in accelerating the translation and widespread adoption of USN technology in biomedical research.

Impact of chemical structure on the in vitro hydrolysis of fatty esters of 2-ethylhexanoic acid or 2-ethylhexanol and extrapolation to the in vivo situation

Fatty esters of 2-ethylhexanoic acid (EHA) and 2-ethylhexanol (EH) are commonly used in cosmetics. Human liver and skin S9 and human plasma were used to determine the in vitro rates of clearance (CL_int) of a series of compounds, with a range of 2-11 carbons on the acid or alcohol moiety and branching at the C2 position. The impact of carbon chain length on in vitro CL_int was most prominent for the liver metabolism of esters of EH, while for in vitro skin metabolism it was greater for esters of EHA. The position of the branching also impacted the liver hydrolysis rates, especially for the C3, C4, and C5 esters with lower CL_{int in vitro} rates for esters of EHA relative to those of EH. When the in vitro intrinsic clearance rates were scaled to in vivo rates of hepatic clearance, all compounds approximated the rate for hepatic blood flow, mitigating this dependence of metabolism on structure. This work shows how structural changes to the molecule can affect in vitro metabolism and, furthermore, allows for an estimation of the in vivo metabolism.

Does Clearance of Vulvar Lichen Sclerosus after a Corticosteroid Treatment Correspond to a Decrease in Disease-Related Burden? Results from a Cohort Study Using Pictorial Representation of Illness and Self-Measure and the Dermatology Life Quality Index

BACKGROUND AND OBJECTIVES

Complete clearance of vulvar lichen sclerosus (VLS) occurs in a minority of treated patients. Disease persistence may impact patient well-being. The main objective of this study was to assess if achieving a complete clearance with a corticosteroid treatment leads to a benefit in terms of patient suffering and quality-of-life (QoL) impairment.

METHODS

We performed an observational study on a cohort of VLS women, who applied mometasone furoate 0.1% ointment for 12 weeks. At treatment completion (T1), we compared the patients who achieved clearance in symptoms (Global Subjective Score [GSS] = 0) or in objective features (Global Objective Score [GOS] = 0) or in both with those who achieved a lower degree of improvement, on the basis of Pictorial Representation of Illness and Self-Measure (PRISM) and Dermatology Life Quality Index (DLQI) scores.

RESULTS

In the whole sample (n = 101), GSS, GOS, PRISM, and DLQI scores significantly improved after treatment from baseline; 34 patients (35.8%) achieved GSS = 0, 26 (25.7%) achieved GOS = 0, and 11 (11.5%) clearance of GSS and GOS. PRISM scores at T1 were significantly higher in patients who achieved clearance of symptoms when compared with those who did not, including patients achieving 50-99% GSS improvement from baseline. DLQI scores were lower in patients who achieved clearance of symptoms, signs, or both when compared with the others.

CONCLUSIONS

VLS clearance corresponded to a significant improvement in the QoL of VLS patients, also in comparison with those who achieved a substantial but incomplete decrease of symptom and sign scores, and should become an ideal therapeutic goal.

Improved Predictability of Hepatic Clearance with Optimal pH for Acyl-Glucuronidation in Liver Microsomes

The purpose of this study was to investigate the optimal pH for acyl-glucuronidation formation with carboxylic acid-containing compounds in human and rat liver microsomes to improve the predictability of their hepatic clearance. The optimal pH for acyl-glucuronidation of all 17 compounds was around pH 6.0 in human and rat liver microsomes. Correlation analysis was done with the predicted in vitro intrinsic clearance (CL_{int,in vitro}) and in vivo intrinsic clearance (CL_{int,in vivo}) calculated from available reported data of total clearance (CL_tot) of 11 compounds in humans. For 8 of the 11 compounds, under the pH 6.0 condition, the CL_{int,in vitro} were within 1/3 to 3-fold error of the observed CL_{int,in vivo} whereas, the error was within 1/3 to 3-fold of the observed CL_{int,in vivo} for only 3 of the 11 under the pH 7.4 condition. The intracellular pH in human and rat hepatocytes decreased in the presence of a carboxylic acid-containing compound. These findings suggest that acyl-glucuronidation in liver microsomes at pH 6.0 is closer to physiological conditions in the presence of carboxylic acid compounds, and thus, use of this pH condition is important for physiological interpretation and predictability of intrinsic clearance.

Review of the application of Kirchhoff's Laws of series and parallel flows to pharmacology: Defining organ clearance

Dosing rate decisions for drugs and changes in dosing in a patient due to disease states, drug interactions and pharmacogenomics are all based on clearance, a measure of the body's ability to eliminate drug. The primary organs of elimination are the liver and the kidney. Clearance for each of these organs is a summative composition of biologic processes. In 1857, Gustav Kirchhoff first developed his laws to describe the "motion of electricity in conductors... [and] ...in wires", recognizing that summative processes occur either in parallel or in series. Since then, Kirchhoff's Laws have also been applied to heat transfer, diffusion and drag force on falling objects, but not to pharmacology. Although not previously recognized, renal clearance always follow Kirchhoff's Laws, as does hepatic clearance for drugs where basolateral transporters are not clinically relevant. However, when basolateral transporters are clinically relevant, we demonstrate that the present accepted approach is inconsistent with recognized drug disposition processes. However, this clearance relationship can be easily corrected using Kirchhoff's Laws. The purpose of this review is to demonstrate that Kirchhoff's Laws, which define how to approach rate processes that occur in parallel versus processes that occur in series, can be applicable to pharmacology in addition to the over 160-year recognition of their use in physical sciences. We anticipate that the application to clearance will be only the first of many such pharmacological analyses.

Drug pharmacokinetics in the obese population: challenging common assumptions on predictors of obesity-related parameter changes

INTRODUCTION

Obesity is associated with many physiological changes. We review available evidence regarding five commonly accepted assumptions to a priori predict the impact of obesity on drug pharmacokinetics (PK).

AREAS COVERED

The investigated assumptions are: 1) lean body weight is the preferred descriptor of clearance and dose adjustments; 2) volume of distribution increases for lipophilic, but not for hydrophilic drugs; 3) CYP-3A4 activity is suppressed and UGT activity is increased, implying decreased and increased dose requirements for substrates of these enzyme systems, respectively; 4) glomerular filtration rate is enhanced, necessitating higher doses for drugs cleared through glomerular filtration; 5) drug dosing information from obese adults can be extrapolated to obese adolescents.

EXPERT OPINION

Available literature contradicts, or at least limits the generalizability, of all five assumptions. Clinical studies should focus on quantifying the impact of duration and severity of obesity on drug PK in adults and adolescents, and also include oral bioavailability and pharmacodynamics in these studies. Physiologically-based PK approaches can be used to predict PK changes for individual drugs, but can also be used to define in general terms based on patient characteristics and drug properties, when certain assumptions can or cannot be expected to be systematically accurate.

Biokinetics of fluorophore-conjugated polystyrene microplastics in marine mussels

Biokinetic information on microplastics in bivalves is required to reduce the human exposure, but little is known about the time-course and size effect on tissue absorption and clearance. The biokinetics of fluorophore-labeled polystyrene microbeads with diameters 10 µm (PL10) and 90 µm (PL90) in Mytilus galloprovincialis marine mussels was investigated in the present study. It was found that both PL10 and PL90 showed a biphasic tissue distribution pattern in digestive and non-digestive tissues, highlighting the significant tissue distribution starting from 48 h post-treatment. The differential size effect on tissue distribution was observed only in the gills, which suggests that PL10 accumulates more than PL90. The depuration kinetics show that particles of both sizes can be cleared in any tissue, but non-digestive tissue requires a longer duration for depuration than digestive tissue. The differential size effect on depuration was observed for both digestive and non-digestive tissues, suggesting that PL10 needed a longer duration for depuration than PL90. More than seven days were needed for depuration of microplastics in mussels, which is an exceptionally longer period compared to conventional depuration of bivalves. The most significant improvement of this study is providing the biokinetics of two different-sized microplastics in mussels and the differential time for purging microplastics from mussels.

Inflammation resolution in environmental pulmonary health and morbidity

Inflammation and resolution are dynamic processes comprised of inflammatory activation and neutrophil influx, followed by mediator catabolism and efferocytosis. These critical pathways ensure a return to homeostasis and promote repair. Over the past decade research has shown that diverse mediators play a role in the active process of resolution. Specialized pro-resolving mediators (SPMs), biosynthesized from fatty acids, are released during inflammation to facilitate resolution and are deficient in a variety of lung disorders. Failed resolution results in remodeling and cellular deposition through pro-fibrotic myofibroblast expansion that irreversibly narrows the airways and worsens lung function. Recent studies indicate environmental exposures may perturb and deregulate critical resolution pathways. Environmental xenobiotics induce lung inflammation and generate reactive metabolites that promote oxidative stress, injuring the respiratory mucosa and impairing gas-exchange. This warrants recognition of xenobiotic associated molecular patterns (XAMPs) as new signals in the field of inflammation biology, as many environmental chemicals generate free radicals capable of initiating the inflammatory response. Recent studies suggest that unresolved, persistent inflammation impacts both resolution pathways and endogenous regulatory mediators, compromising lung function, which over time can progress to chronic lung disease. Chronic ozone (O3) exposure overwhelms successful resolution, and in susceptible individuals promotes asthma onset. The industrial contaminant cadmium (Cd) bioaccumulates in the lung to impair resolution, and recurrent inflammation can result in chronic obstructive pulmonary disease (COPD). Persistent particulate matter (PM) exposure increases systemic cardiopulmonary inflammation, which reduces lung function and can exacerbate asthma, COPD, and idiopathic pulmonary fibrosis (IPF). While recurrent inflammation underlies environmentally induced pulmonary morbidity and may drive the disease process, our understanding of inflammation resolution in this context is limited. This review aims to explore inflammation resolution biology and its role in chronic environmental lung disease(s).

Comparison of pharmacokinetic parameters of ranolazine between diabetic and non-diabetic rats

OBJECTIVES

Diabetes mellitus (DM) affects the pharmacokinetics of drugs. Ranolazine is an antianginal drug that is prescribed in DM patients with angina. We decided to evaluate the effect of DM on the pharmacokinetics of ranolazine and its major metabolite CVT-2738 in rats.

MATERIALS AND METHODS

Male rats were divided into two groups: DM (induced by 55 mg/kg Streptozotocin (STZ)) and non-DM. All animals were treated with 80 mg/kg of ranolazine for 7 continuous days. The blood samples were collected immediately at 0 (prior to dosing), 1, 2, 3, 4, 8, and 12 hr after administration of the 7th dose of ranolazine. Serum ranolazine and CVT-2738 concentrations were determined using the high-performance liquid chromatography (HPLC) method. Pharmacokinetic parameters were calculated using a non-compartmental model and compared between the two groups.

RESULTS

The peak serum concentration (Cmax) and area under the curve (AUC) of ranolazine significantly decreased in DM compared with non-DM rats. DM rats showed significantly higher volumes of distribution (Vd) and clearance (CL) of ranolazine than non-DM rats. DM did not affect Ke, Tmax, and T1/2 of ranolazine. The concentration of metabolite was lower than the HPLC limit of detection (LOD).

CONCLUSION

It was found that streptozotocin-induced DM increased Vd and CL of ranolazine, thereby decreasing the AUC of the drug. Therefore, dosage adjustment may be necessary for DM patients, which requires further clinical studies.

Population pharmacokinetic modeling of CSF to blood clearance: prospective tracer study of 161 patients under work-up for CSF disorders

Background

Quantitative measurements of cerebrospinal fluid to blood clearance has previously not been established for neurological diseases. Possibly, variability in cerebrospinal fluid clearance may affect the underlying disease process and may possibly be a source of under- or over-dosage of intrathecally administered drugs. The aim of this study was to characterize the cerebrospinal fluid to blood clearance of the intrathecally administered magnetic resonance imaging contrast agent gadobutrol (Gadovist, Bayer Pharma AG, GE). For this, we established a population pharmacokinetic model, hypothesizing that cerebrospinal fluid to blood clearance differs between cerebrospinal fluid diseases.

Methods

Gadobutrol served as a surrogate tracer for extra-vascular pathways taken by several brain metabolites and drugs in cerebrospinal fluid. We estimated cerebrospinal fluid to blood clearance in patients with different cerebrospinal fluid disorders, i.e. symptomatic pineal and arachnoid cysts, as well as tentative spontaneous intracranial hypotension due to cerebrospinal fluid leakage, idiopathic intracranial hypertension, or different types of hydrocephalus (idiopathic normal pressure hydrocephalus, communicating- and non-communicating hydrocephalus). Individuals with no verified cerebrospinal fluid disturbance at clinical work-up were denoted references.

Results

Population pharmacokinetic modelling based on 1,140 blood samples from 161 individuals revealed marked inter-individual variability in pharmacokinetic profiles, including differences in absorption half-life (time to 50% of tracer absorbed from cerebrospinal fluid to blood), time to maximum concentration in blood and the maximum concentration in blood as well as the area under the plasma concentration time curve from zero to infinity. In addition, the different disease categories of cerebrospinal fluid diseases demonstrated different profiles.

Conclusions

The present observations of considerable variation in cerebrospinal fluid to blood clearance between individuals in general and across neurological diseases, may suggest that defining cerebrospinal fluid to blood clearance can become a useful diagnostic adjunct for work-up of cerebrospinal fluid disorders. We also suggest that it may become useful for assessing clearance capacity of endogenous brain metabolites from cerebrospinal fluid, as well as measuring individual cerebrospinal fluid to blood clearance of intrathecal drugs.

Dosage Optimization of Lamotrigine in Pregnancy: A Pharmacometric Approach using Modeling and Simulation

Lamotrigine is the most widely used anti-epileptic drug in pregnancy due to its low teratogenicity. However, there is an increased metabolism & clearance of Lamotrigine in pregnancy contributing to suboptimal drug therapy and poor disease control, prompting the need for pro-active dosage adjustments. The present study aimed to develop a pharmacometric model-based framework for recommending optimal dosage regimen for Lamotrigine in pregnancy. A systematic review was performed to obtain the literature aggregate data on clearance of Lamotrigine in pregnancy. The data was incorporated into simulations using PUMAS software for estimating the plasma concentrations at preconception stage and three trimesters. Simulated drug-exposures for different doses were investigated to ascertain plasma concentrations similar to the pre-conception and above minimum effective concentration. The simulated mean steady state trough plasma concentrations (mg/L) of Lamotrigine in non-pregnant and pregnant women at 3 trimesters decreased significantly (p<0.001) viz. 4.31±1.14, 3.17± 0.93, 2.14±0.86, 1.51±0.65 respectively. The simulation studies revealed that 150mg, 175mg, 225mg and 250mg twice daily doses, in pre-conception stage and three trimesters respectively achieve the target concentrations. Thus, the model-informed dosage regimen of Lamotrigine proposed in this study shall be considered to initiate the dosing in pregnant women, however the safety and efficacy of the drug have to be assured through therapeutic drug monitoring, in order to avoid therapeutic failure of Lamotrigine in pregnancy. This article is protected by copyright. All rights reserved.

Accuracy of ct evaluation for cervical spine clearance in the ground level fall population - a retrospective cohort study

Background

Clinically occult cervical spine (CS) injuries are well described in blunt trauma, however delay in identifying these injuries and clearing the CS can result in morbidity. Our study examines the ground level fall (GLF) population to analyze whether computed tomography (CT) alone can rule out unstable injury in this group with lower force mechanism.

Methods

This is a single center, retrospective cohort study. All GLF patients in the institutional trauma registry between 6/1/2012 through 12/31/2019 were included. These comprise all trauma patients evaluated in the emergency department with Injury Severity Score (ISS) > 0, including both activations and consults with both clinical and radiological spine evaluation. Patients who could not be cleared by National Emergency X-ray Utilization Study (NEXUS) criteria underwent CT. Patients with CT or clinical suspicion of cord or ligamentous injury underwent MRI. CT occult injuries were identified by MRI and clinical exam, with MRI identifying all unstable injuries.

Results

Sixty-nine (2.0%) of patients had CS injury without acute CT abnormality. Of these, 11 (0.3%) required surgery and were considered unstable. All patients who required surgery had a neurologic deficit. Negative predictive value (NPV) of CT for unstable CS injury was 99.7%. The combination of acute CT findings and neurologic deficit ruled out unstable CS injury with 100% NPV.

Conclusion

In the GLF population, CT alone rules out unstable CS injury with high, but not perfect NPV. The combination of absence of acute CT findings and acute neurologic deficits rules out unstable CS injury with 100% NPV.

Supplementary information

The online version contains supplementary material available at 10.1186/s12873-022-00657-x.

Estimate and determinants of SARS-CoV-2 RNA clearance time among non-severe COVID-19 patients

Objectives:

To estimate SARS-CoV-2 RNA clearance time among non-severe COVID-19 patients and explore factors associated with delayed negative conversion.

Methods:

A retrospective cohort study was conducted at the COVID-19 unit of a tertiary care center in the Western region of Saudi Arabia. Reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed COVID-19 patients diagnosed between April 1 and June 30, 2020, were considered. The primary outcome was the time (days) from disease onset to first negative RT-PCR, which was analyzed using Kaplan–Meier and Cox regression survival methods. Demographic data, clinical history, baseline clinical, radiological and laboratory findings and management, and outcome data were collected and analyzed as factors associated with the viral RNA clearance time.

Results:

One hundred and forty-four patients were included. The mean (standard deviation [SD]) age was 36.93 (14.41) years, 50.7% were females, and 45.1% were healthcare workers. COVID19 was asymptomatic, mild and moderate in 11.1%, 71.5% and 17.4% of the participants, respectively. Fever (59.4%) and cough (58.0%) were the dominant onset symptoms. The mean viral RNA clearance time was 22.9 days (SD = 8.6; 95% confidence interval [CI] = 21.5–24.3 days). Extended clearance time was associated with older age (mean = 24.0 vs. 22.0 days; log-rank = 0.037), married status (23.2 vs. 22.6 days; log-rank = 0.021), working in health sector (24.2 vs. 21.8 days; log-rank = 0.006), and having a chronic disease (24.8 vs. 21.9 days; log-rank = 0.028), compared to their counterparts, respectively. In the adjusted model, the job sector was the only factor that was independently associated with clearance time. Non-healthcare sector showed hazard ratio 1.8 (95% CI = 1.3–2.7; log-rank = 0.002) with reference to healthcare sector.

Conclusion:

SARS-CoV-2 RNA clearance time is likely to be longer in non-severe COVID-19 patients, representing an additional risk for the virus dissemination among the community and calling for higher caution among the population.

Literature Review of the Efficacy of High-Volume Hemofiltration in Critically Ill Pediatric Patients

BACKGROUND

Pediatric sepsis is a significant public health issue. This condition is exacerbated by rising serum creatinine and inflammatory cytokines that lead to deleterious effects upon the body. The current standard of care involves the use of continuous kidney replacement therapy to remove harmful cytokines until the body returns to homeostasis. In order to promote faster clearance and reduced stay in the ICU, high-volume hemofiltration (HVHF) has shown promise. However, there is a paucity of studies to fully elucidate its benefits.

METHODS

A literature search was done using PubMed/ MEDLINE and Embase. The literature was reviewed by two independent reviewers, who independently assessed the quality of randomized controlled trials by using the Cochrane risk of bias tool for RCTs and Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomized controlled trials. Data were combined from studies with a similar design.

RESULTS

The primary endpoint of all-cause mortality was found to be reduced by 40% across all of the pooled studies. For secondary endpoints, significant reductions of serum creatinine were found. Additionally, duration of ICU stays and treatment course was found to be significantly shorter in HVHF patients than the current standard of care. The rate of adverse effects was analyzed, and there was no difference in the proportion of patients developing hypokalemia, hyperkalemia, hypernatremia, or hyponatremia. The proportion of patients developing hyperglycemia was higher in patients undergoing HVHF, whereas the proportions of patients developing bleeding were significantly less in patients undergoing HVHF. One study reported a total number of adverse events between the two groups which were significantly lesser in patients undergoing HVHF.

CONCLUSION

HVHF shows promise as a modality to treat pediatric patients with sepsis. In order to confirm the benefits of this modality, future studies need significantly more patients for analysis.

Perivascular space dilation is associated with vascular amyloid-β accumulation in the overlying cortex

Perivascular spaces (PVS) are compartments surrounding cerebral blood vessels that become visible on MRI when enlarged. Enlarged PVS (EPVS) are commonly seen in patients with cerebral small vessel disease (CSVD) and have been suggested to reflect dysfunctional perivascular clearance of soluble waste products from the brain. In this study, we investigated histopathological correlates of EPVS and how they relate to vascular amyloid-β (Aβ) in cerebral amyloid angiopathy (CAA), a form of CSVD that commonly co-exists with Alzheimer's disease (AD) pathology. We used ex vivo MRI, semi-automatic segmentation and validated deep-learning-based models to quantify EPVS and associated histopathological abnormalities. Severity of MRI-visible PVS during life was significantly associated with severity of MRI-visible PVS on ex vivo MRI in formalin fixed intact hemispheres and corresponded with PVS enlargement on histopathology in the same areas. EPVS were located mainly around the white matter portion of perforating cortical arterioles and their burden was associated with CAA severity in the overlying cortex. Furthermore, we observed markedly reduced smooth muscle cells and increased vascular Aβ accumulation, extending into the WM, in individually affected vessels with an EPVS. Overall, these findings are consistent with the notion that EPVS reflect impaired outward flow along arterioles and have implications for our understanding of perivascular clearance mechanisms, which play an important role in the pathophysiology of CAA and AD.

Ammonia Clearance with Different Continuous Renal Replacement Therapy Techniques in Patients with Liver Failure

INTRODUCTION

Continuous renal replacement therapy (CRRT) can be used to treat hyperammonaemia. However, no study has assessed the effect of different CRRT techniques on ammonia clearance.

METHODS

We compared 3 different CRRT techniques in adult patients with hyperammonaemia, liver failure, and acute kidney injury. We protocolized CRRT to progressively deliver continuous veno-venous haemofiltration (CVVH), haemodialysis (CVVHD) or haemodiafiltration (CVVHDF). Ammonia was simultaneously sampled from the patient's arterial blood and effluent fluid for each technique. We applied accepted equations to calculate clearance.

RESULTS

We studied 12 patients with a median age of 47 years (interquartile range [IQR] 25-79). Acute liver failure was present in 4 (25%) and acute-on-chronic liver failure in 8 (75%). There was no significant difference in median ammonia clearance between CRRT technique; CVVH: 27 (IQR 23-32) mL/min versus CVVHD: 21 (IQR 17-28) mL/min versus CVVHDF: 20 (IQR 14-28) mL/min, p = 0.32. Moreover, for all techniques, ammonia clearance was significantly less than urea and creatinine clearance; urea 50 (47-54) mL/min versus creatinine 42 (IQR 38-46) mL/min versus ammonia 25 (IQR 18-29) mL/min, p = 0.0001.

CONCLUSION

We found no significant difference in ammonia clearance according to CRRT technique and demonstrated that ammonia clearance is significantly less than urea or creatinine clearance.

Recent advancements in clearance monitoring of monoclonal antibodies in patients with inflammatory bowel diseases

INTRODUCTION

Less than 50% of patients with inflammatory bowel diseases (IBD) receiving monoclonal antibody (mAb) therapy achieve endoscopic remission. Poor outcomes may indicate a need for dose optimization. During therapeutic drug monitoring (TDM), drug concentrations are measured, and when found too low, dosage regimen escalations are performed. To date, benefits of TDM of mAbs in patients with IBD are uncertain.

AREAS COVERED

This review presents an overview of what clearance monitoring is, how it can be performed, and why and when it may be valuable in treating patients with IBD. Virtual patients were used for illustration. A literature search was performed to summarize current evidence for clearance monitoring in IBD and other disease settings.

EXPERT OPINION

During clearance monitoring, mAb clearance is calculated and monitored over time. Higher mAb clearance in patients with IBD has been associated with higher target load (target-mediated drug disposition), protein-losing enteropathy (fecal drug loss), and immunogenicity. Although not prospectively confirmed, clearance monitoring might facilitate identification of (yet) asymptomatic disease flares or presence of (yet) undetectable anti-drug antibodies. Furthermore, clearance monitoring may be used to predict treatment outcomes. Whether dosage regimen adjustments can modify the clearance time course and the treatment outcome is to be determined.

Enhanced external counterpulsation: A new method to alleviate contrast-induced acute kidney injury

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a common complication after exposure to contrast media. Renal ischaemia occurs in the initial stage of CI-AKI, however, there are very few effective measures to improve renal perfusion.

METHODS

A total of 114 patients with an estimated glomerular filtration rate (eGFR) of 60-89 ml/min/1.73m² were randomly assigned to two groups: enhanced external counterpulsation (EECP) group (N = 57) and control group (N = 57). Two hours after contrast exposure, EECP group received EECP treatment for 1 h while no intervention was performed control group. The primary outcome was the incidence of serum cystatin C concentration to 10% above the baseline concentration at 24 h after contrast administration. The secondary outcomes were the incidence of CI-AKI (defined as an increase in serum creatinine concentration to ≥0.5 mg/dl or by 25% compare to the baseline after contrast exposure), contrast clearance and adverse clinical events.

RESULTS

The primary outcome was observed in 26 patients (6 EECP and 20 control; 11% vs. 35%; P = 0.002). CI-AKI occurred in four patients (0 EECP and 4 control; 0% vs. 7%; P = 0.042). The clearance rate of iopromide in the initial 3 h was significantly different between EECP and control group (59.92 ± 8.84 vs 46.80 ± 9.26 ml/min/1.73 m²; P < 0.001). No adverse clinical events were observed in this study.

CONCLUSIONS

This study demonstrates that EECP increases the contrast clearance and may have an effect in reducing the risk of CI-AKI. The study has been registered in Chinese Clinical Trial Registry (ChiCTR 2,000,039,190).

Effect of Normalizing eGFR to Standard Body Surface Area on Rates of Obesity-Related Hyperfiltration among Diverse Female Adolescents

INTRODUCTION

Obesity is more prevalent among African American individuals, increasing the risk for cardiorenal morbidity. We explored interactions between race, BMI, and the risk of hyperfiltration associated with obesity-related glomerulopathy (ORG).

METHODS

We created a cohort of female adolescents from electronic health records. Glomerular filtration rate (GFR) was estimated in two ways: (A) using standard age recommended formulae and (B) absolute eGFR - adjusted to individual body surface area (BSA). Multivariate logistic regression was used to analyze the contribution of risk factors for ORG-associated hyperfiltration defined as 135 mL/min/1.73 m2 or 135 mL/min, according to BMI group. Pearson's coefficient was used to assess correlation with creatinine clearance (CrCl).

RESULTS

The final cohort included 7,315 African American and 15,102 non-African American adolescent females, with CrCl available for internal validation in 207 non-African American and 107 African American individuals. Compared with non-African American ethnicity, African American ethnicity was independently associated with a lower risk of hyperfiltration with standard eGFR calculations (odds ratio [OR] = 0.57, 95% confidence intervals [CIs] 0.45-0.71), associations were enhanced for absolute eGFR (OR = 0.81, 95% CI 0.69-0.95). Absolute eGFR values agreed better with CrCl (r = 0.63), compared to standard indexed eGFR formulae. Proportions classified as hyperfiltration changed with standard versus absolute eGFR; they were similar across BMI groups with the first and reflected obesity with the later.

CONCLUSION

Adjusting to individual BSA improves estimation of GFR and identification of obesity-related hyperfiltration. More accurate and earlier ascertainment of obesity-related hyperfiltration may have important consequences for preservation of kidney function.