Associations between vitamin D status, VDR gene polymorphisms and echocardiographic markers in Polish patients with cardiovascular disease.

Aim: This work was designed to investigate the associations between vitamin D metabolites, VDR gene polymorphisms and echocardiographic markers in a population of patients with cardiovascular disease. Methods: Echocardiographic markers for 42 patients were determined with tissue Doppler techniques. PCR-restriction fragment length polymorphism analysis identified genetic variants ApaI, TaqI, BsmI and FokI. A validated UHPLC-MS/MS method determined vitamin D metabolites. Results: Patients with the ApaI-GT genotype exhibited a lower pressure gradient across the aortic valve than ApaI-TT carriers. BMI, ApaI-GT, TaqI-TC, aortic arch diameter and maximal pressure gradient were significant univariate predictors of hypertension. Conclusion: A potential link exists between VDR gene polymorphisms and cardiovascular function.

Vitamin D levels in the body and variations in the vitamin D receptor gene are linked to specific heart-related markers in Polish patients with heart conditions. What is this article about? Coronary artery disease is a global health issue and the third leading cause of death. While many factors are understood to contribute to coronary artery disease, there is ongoing debate about whether vitamin D deficiency is one of them. In the past 10 years, there has been extensive research on vitamin D deficiency, characterizing it as a kind of 'pandemic' affecting a large portion of the population. Vitamin D deficiency is associated with more severe cardiovascular health issues and a higher risk of mortality. Why did we conduct this study? This study was designed to assess how different forms of vitamin D (created in the body) and genetic differences relate to heart health in people with cardiovascular disease and how they might be linked to markers observed in heart imaging. What were the results & what do they mean? Some genes seem to be more protective against hypertension than others. Some forms of vitamin D and genetic differences were linked to changes in markers observed in heart imaging. Adult patients should consume around 1000 to 2000 IU of vitamin D per day to contribute to better overall heart health.

Development and Validation of a UPLC-MS/MS Method for Therapeutic Drug Monitoring, Pharmacokinetic and Stability Studies of First-Line Antituberculosis Drugs in Urine.

Tuberculosis (TB) remains one of the leading global causes of mortality. Several methods have been established to detect anti-TB agents in human plasma and serum. However, there is a notable absence of studies analyzing TB drugs in urine. Thus, our objective was to validate a method for quantifying first-line anti-TB agents: isoniazid (INH), pyrazinamide (PZA), ethambutol (ETH), and rifampicin (RIF), along with its metabolite 25-desacetylrifampicin, and degradation products: rifampicin quinone and 3-formyl-rifampicin in 10 µL of urine. Chromatographic separation was achieved using a Kinetex Polar C18 analytical column with gradient elution (5 mM ammonium acetate and acetonitrile with 0.1% formic acid). Mass spectrometry detection was carried out using a triple-quadrupole tandem mass spectrometer operating in positive ion mode. The lower limit of quantification (LLOQ) was 0.5 µg/mL for INH, PZA, ETH, and RIF, and 0.1 µg/mL for RIF's metabolites and degradation products. The method was validated following FDA guidance criteria and successfully applied to the analysis of the studied compounds in urine of TB patients. Additionally, we conducted a stability study of the anti-TB agents under various pH and temperature conditions to mimic the urine collection process in different settings (peripheral clinics or central laboratories).

Challenging the Norm: A Multidisciplinary Perspective on Intravenous to Subcutaneous Bridging Strategies for Biologics.

The transition from intravenous (i.v.) to subcutaneous (s.c.) administration of biologics is a critical strategy in drug development aimed at improving patient convenience, compliance, and therapeutic outcomes. Focusing on the increasing role of model-informed drug development (MIDD) in the acceleration of this transition, an in-depth overview of the essential clinical pharmacology, and regulatory considerations for successful i.v. to s.c. bridging for biologics after the i.v. formulation has been approved are presented. Considerations encompass multiple aspects beginning with adequate pharmacokinetic (PK) and pharmacodynamic (i.e., exposure-response) evaluations which play a vital role in establishing comparability between the i.v. and s.c. routes of administrations. Selected key recommendations and points to consider include: (i) PK characterization of the s.c. formulation, supported by the increasing preclinical understanding of the s.c. absorption, and robust PK study design and analyses in humans; (ii) a thorough characterization of the exposure-response profiles including important metrics of exposure for both efficacy and safety; (iii) comparability studies designed to meet regulatory considerations and support approval of the s.c. formulation, including noninferiority studies with PK and/or efficacy and safety as primary end points; and (iv) comprehensive safety package addressing assessments of immunogenicity and patients' safety profile with the new route of administration. Recommendations for successful bridging strategies are evolving and MIDD approaches have been used successfully to accelerate the transition to s.c. dosing, ultimately leading to improved patient experiences, adherence, and clinical outcomes.

Physiologically-Based Modeling and Interspecies Prediction of Cisplatin Pharmacokinetics.

The goal of this work was to develop a physiologically-based pharmacokinetic (PBPK) modeling framework for cisplatin. The model was constructed based on 11 published data sets from rodents; and rabbit, dog, and human data were used to evaluate its utility in predicting plasma and tissue distribution of platinum in larger species, including humans. The model included biotransformation of cisplatin into mobile (k1) and fixed (k2) metabolites in all tissues, and subsequent conversion of fixed metabolites to mobile metabolites (k3) due to protein degradation and turnover. The model successfully captured complex pharmacokinetics of platinum in rodents, and all parameters were estimated with sufficient precision. A separate k2 parameter was estimated for each included tissue, and the relationship between the rates of formation of mobile and fixed metabolites was established through a scaling factor (k1=k2·SF, SF=0.74). For interspecies predictions, k1 and k2 were shared across all species, and k3 was scaled allometrically based on protein turnover rate (with an exponent of -0.28). Scaled PBPK model provided a good prediction of total platinum profiles in humans and reasonably captured platinum measurements in human tissues (as obtained from autopsy).

Target Reserve and Turnover Parameters Determine Rightward Shift of Enalaprilat Potency From its Binding Affinity to the Angiotensin Converting Enzyme.

Drug effects are often assumed to be directly proportional to the fraction of occupied targets. However, for a number of antagonists that exhibit target-mediated drug disposition (TMDD), such as angiotensin-converting enzyme (ACE) inhibitors, drug binding to the target at low concentrations may be significant enough to influence pharmacokinetics but insufficient to elicit a drug response (i.e., differences in drug-target binding affinity and potency). In this study, a pharmacokinetic/pharmacodynamic model for enalaprilat was developed in humans to provide a theoretical framework for assessing the relationship between ex vivo drug potency (IC50) and in vivo target-binding affinity (KD). The model includes competitive binding of angiotensin I and enalaprilat to ACE and accounts for the circulating target pool. Data were obtained from the literature, and model fitting and parameter estimation were conducted using maximum likelihood in ADAPT5. The model adequately characterized time-courses of enalaprilat concentrations and four biomarkers in the renin-angiotensin system and provided estimates for in vivo KD (0.646 nM) and system-specific parameters, such as total target density (32.0 nM) and fraction of circulating target (19.8%), which were in agreement with previous reports. Model simulations were used to predict the concentration-effect curve of enalaprilat, revealing a 6.3-fold increase in IC50 from KD. Additional simulations demonstrated that target reserve and degradation parameters are key factors determining the extent of shift of enalaprilat ex vivo potency from its in vivo binding affinity. This may be a common phenomenon for drugs exhibiting TMDD and has implications for translating binding affinity to potency in drug development.

Simplified urine-based method to detect rifampin underexposure in adults with tuberculosis: a prospective diagnostic accuracy study.

Variable pharmacokinetics of rifampin in tuberculosis (TB) treatment can lead to poor outcomes. Urine spectrophotometry is simpler and more accessible than recommended serum-based drug monitoring, but its optimal efficacy in predicting serum rifampin underexposure in adults with TB remains uncertain. Adult TB patients in New Jersey and Virginia receiving rifampin-containing regimens were enrolled. Serum and urine samples were collected over 24 h. Rifampin serum concentrations were measured using validated liquid chromatography-tandem mass spectrometry, and total exposure (area under the concentration-time curve) over 24 h (AUC0-24) was determined through noncompartmental analysis. The Sunahara method was used to extract total rifamycins, and rifampin urine excretion was measured by spectrophotometry. An analysis of 58 eligible participants, including 15 (26%) with type 2 diabetes mellitus, demonstrated that urine spectrophotometry accurately identified subtarget rifampin AUC0-24 at 0-4, 0-8, and 0-24 h. The area under the receiver operator characteristic curve (AUC ROC) values were 0.80 (95% CI 0.67-0.90), 0.84 (95% CI 0.72-0.94), and 0.83 (95% CI 0.72-0.93), respectively. These values were comparable to the AUC ROC of 2 h serum concentrations commonly used for therapeutic monitoring (0.82 [95% CI 0.71-0.92], P = 0.6). Diabetes status did not significantly affect the AUC ROCs for urine in predicting subtarget rifampin serum exposure (P = 0.67-0.92). Spectrophotometric measurement of urine rifampin excretion within the first 4 or 8 h after dosing is a simple and cost-effective test that accurately predicts rifampin underexposure. This test provides critical information for optimizing tuberculosis treatment outcomes by facilitating appropriate dose adjustments.

An LC-ESI-MS/MS method for determination of ondansetron in low-volume plasma and cerebrospinal fluid: Method development, validation, and clinical application.

Ondansetron is used in clinical settings as an antiemetic drug. Although the animal studies showed its potential effectiveness also in treating neuropathic pain, the results from humans are inconclusive. The lack of efficacy of ondansetron in a subset of patients might be due to the overexpression of P-glycoprotein, which could result in low concentrations of ondansetron in the central nervous system (CNS). A surrogate of the CNS exposure might be drug concentration in the cerebrospinal fluid (CSF), especially in humans, as assessing the drug disposition directly in the patient's brain would be challenging. The study aimed to develop a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine concentrations of ondansetron in human K3EDTA plasma and CSF. Ondansetron was extracted from biological matrices by liquid-liquid extraction. The quantification was performed on a Sciex QTRAP 6500+ mass spectrometer with labeled ondansetron as an internal standard. The calibration range was 0.25-350 ng/mL in plasma and 0.025-100 ng/mL in CSF; for both matrices, 25 µL of samples was required for the assays. The method was validated according to the FDA and EMA guidelines and showed acceptable results. A pilot study confirmed its suitability for clinical samples: after 4-16 mg of intravenous ondansetron, the determined concentrations in plasma were 1.22-235.90 ng/mL, while in CSF - 0.018-11.93 ng/mL. In conclusion, the developed method fulfilled all validation requirements and can be applied to pharmacokinetic studies assessing the CNS ondansetron exposure in humans. The method's advantages, such as a low volume of matrix and a wide calibration range, support its use in a study in which rich sampling and various drug doses are expected.

New approach to rifampicin stability and first-line anti-tubercular drug pharmacokinetics by UPLC-MS/MS.

Successful tuberculosis (TB) therapy requires achieving sufficient exposure to multiple drugs. Limited stability of several first-line anti-TB drugs might compromise reliable therapeutic drug monitoring (TDM). We developed and validated a sensitive and selective UPLC-MS/MS method for simultaneous quantification of isoniazid (INH), pyrazinamide (PZA), rifampicin (RIF), its metabolite 25-desacetylrifampicin and degradation products: rifampicin quinone and 3-formyl-rifampicin. Analysis was completed from a very small plasma volume (20 µL) using only protein precipitation with methanol. Chromatographic separation was achieved on a Kinetex Polar C18 column (2.6 µm; 150 × 3 mm) with a mobile phase consisting of 5 mM ammonium acetate and acetonitrile, both containing 0.1 % formic acid, in gradient elution. The analytes were detected using a positive ionization mode by multiple reaction monitoring. The LLOQ for RIF and its degradation products was 0.1 µg/mL, 0.05 µg/mL for INH, and 0.2 µg/mL for PZA. The method was validated based on the FDA guidance. The application of the method was confirmed in the analysis of RIF, INH, and PZA, as well as RIF metabolism/degradation products in plasma samples of patients with TB. Based on the detailed stability study of the analyzed compounds at various storage conditions, we proposed recommendations for handling the plasma and serum samples in TDM and other pharmacokinetic studies.

Rifampin urinary excretion to predict serum targets in children with tuberculosis: a prospective diagnostic accuracy study.

OBJECTIVE: Pharmacokinetic variability drives tuberculosis (TB) treatment outcomes but measurement of serum drug concentrations for personalised dosing is inaccessible for children in TB-endemic settings. We compared rifampin urine excretion for prediction of a serum target associated with treatment outcome. DESIGN: Prospective diagnostic accuracy study. SETTING: Inpatient wards and outpatient clinics, northern Tanzania. PATIENTS: Children aged 4-17 years were consecutively recruited on initiation of WHO-approved treatment regimens. INTERVENTIONS: Samples were collected after directly observed therapy at least 2 weeks after initiation in the intensive phase: serum at pre-dose and 1, 2 and 6 hours post-dose, later analysed by liquid chromatography-tandem mass spectrometry for calculation of rifampin total exposure or area under the concentration time curve (AUC0-24); urine at post-dose intervals of 0-4, 4-8 and 8-24 hours, with rifampin excretion amount measured onsite by spectrophotometry. MAIN OUTCOME MEASURES: Receiver operating characteristic (ROC) curve for percentage of rifampin dose excreted in urine measured by spectrophotometry to predict serum rifampin AUC0-24 target of 31.7 mg*hour/L. RESULTS: 89 children, 52 (58%) female, with median age of 9.1 years, had both serum and urine collection. Only 59 (66%) reached the serum AUC0-24 target, reflected by a range of urine excretion patterns. Area under the ROC curve for percentage of rifampin dose excreted in urine over 24 hours predicting serum AUC0-24 target was 69.3% (95% CI 56.7% to 81.8%), p=0.007. CONCLUSIONS: Urine spectrophotometry correlated with a clinically relevant serum target for rifampin, representing a step toward personalised dosing for children in TB-endemic settings.

The influence of SARS-CoV-2 infection on expression of drug-metabolizing enzymes and transporters in a hACE2 murine model.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting Coronavirus disease 2019 emerged in late 2019 and is responsible for significant morbidity and mortality worldwide. A hallmark of severe COVID-19 is exaggerated systemic inflammation, regarded as a "cytokine storm," which contributes to the damage of various organs, primarily the lungs. The inflammation associated with some viral illnesses is known to alter the expression of drug-metabolizing enzymes and transporters. These alterations can lead to modifications in drug exposure and the processing of various endogenous compounds. Here, we provide evidence to support changes in the mitochondrial ribonucleic acid expression of a subset of drug transporters (84 transporters) in the liver, kidneys, and lungs and metabolizing enzymes (84 enzymes) in the liver in a humanized angiotensin-converting enzyme 2 receptor mouse model. Specifically, three drug transporters (Abca3, Slc7a8, Tap1) and the pro-inflammatory cytokine IL-6 were upregulated in the lungs of SARS-CoV-2 infected mice. We also found significant downregulation of drug transporters responsible for the movement of xenobiotics in the liver and kidney. Additionally, expression of cytochrome P-450 2f2 which is known to metabolize some pulmonary toxicants, was significantly decreased in the liver of infected mice. The significance of these findings requires further exploration. Our results suggest that further research should emphasize altered drug disposition when investigating therapeutic compounds, whether re-purposed or new chemical entities, in other animal models and ultimately in individuals infected with SARS-CoV-2. Moreover, the influence and impact of these changes on the processing of endogenous compounds also require further investigation.

Mechanisms of Obesity-Induced Changes in Pharmacokinetics of IgG in Rats.

PURPOSE: To evaluate how obesity affects the pharmacokinetics of human IgG following subcutaneous (SC) and intravenous (IV) administration to rats and the homeostasis of endogenous rat IgG. METHODS: Differences in body weight and size, body composition, and serum concentration of endogenous rat IgG in male Zucker obese (ZUC-FA/FA) and control (ZUC-LEAN) rats were measured from the age of 5 weeks up to 30 weeks. At the age of 23-24 weeks animals received a single IV or SC dose of human IgG (1 g/kg of total body weight), and serum pharmacokinetics was followed for 7 weeks. A mechanistic model linking obesity-related changes in pharmacokinetics with animal growth and changes in body composition was developed. RESULTS: Significant differences were observed in both endogenous and exogenous IgG pharmacokinetics between obese and control groups. The AUC for human IgG was lower in obese groups (57.6% of control after IV and 48.1% after SC dosing), and clearance was 1.75-fold higher in obese animals. The mechanistic population model successfully captured the data and included several major components: endogenous rat IgG homeostasis with age-dependent synthesis rate; competition of human IgG and endogenous rat IgG for FcRn binding and its effect on endogenous rat IgG concentrations following injection of a high dose of human IgG; and the effect of body size and composition (changing over time and dependent on the obesity status) on pharmacokinetic parameters. CONCLUSIONS: We identified important obesity-induced changes in the pharmacokinetics of IgG. Results can potentially facilitate optimization of the dosing of IgG-based therapeutics in the obese population.

Relationship between Body Composition and Serum Immunoglobulin Concentrations after Administration of Intravenous Immune Globulin-Preclinical and Clinical Evidence.

The purpose of this study was to investigate the effect of obesity on immunoglobulin G (IgG) pharmacokinetics in a rat model of obesity, and to collect clinical evidence for an association between the body composition and intravenous immune globulin (IVIG) pharmacokinetic parameters in humans. In a preclinical study, pharmacokinetics of human IgG was evaluated after intravenous (IV) and subcutaneous (SC) delivery to obese and lean rats (n = 6 in each group). Serial serum samples were analyzed using an ELISA. The animal body composition was assessed using computer tomography. Patients with primary immunodeficiency currently managed with IVIG, and at a steady state, were enrolled in the clinical study (n = 8). Serum immune globulin (Ig) concentrations were measured at baseline and immediately after the administration of two consecutive treatments, with an additional measurement at two weeks after the first administration. In addition to the patient demographic and clinical characteristics, body composition was measured using bioelectrical impedance analysis. The pharmacokinetics of human IgG was significantly different between the obese and lean rats after both the IV and SC administration of 0.5 g/kg. Furthermore, a significant difference in endogenous rat IgG was observed between the two strains. In the human study, total serum IgG and subtype (IgG1, IgG2, IgG3, IgG4) half-life negatively correlated with the body mass index and fat mass. The mean change in the total serum IgG concentration was significantly correlated to body mass index and fat mass. The results of the studies corroborated one another. In the animal study, most pharmacokinetic parameters of human IgG following IV and SC administration were significantly affected by obesity and changes in the body composition. In the clinical study, the mean serum IgG change after the IVIG administration strongly correlated to the BMI and body fat mass. Future studies are needed to establish the outcomes achieved with more frequent dosing in obese individuals with primary immunodeficiency.

A Reactive Oxygen Species-Scavenging 'Stealth' Polymer, Poly(thioglycidyl glycerol), Outperforms Poly(ethylene glycol) in Protein Conjugates and Nanocarriers and Enhances Protein Stability to Environmental and Biological Stressors.

This study addresses well-known shortcomings of poly(ethylene glycol) (PEG)-based conjugates. PEGylation is by far the most common method employed to overcome immunogenicity and suboptimal pharmacokinetics of, for example, therapeutic proteins but has significant drawbacks. First, PEG offers no protection from denaturation during lyophilization, storage, or oxidation (e.g., by biological oxidants, reactive oxygen species); second, PEG's inherent immunogenicity, leading to hypersensitivity and accelerated blood clearance (ABC), is a growing concern. We have here developed an 'active-stealth' polymer, poly(thioglycidyl glycerol)(PTGG), which in human plasma is less immunogenic than PEG (35% less complement activation) and features a reactive oxygen species-scavenging and anti-inflammatory action (∼50% less TNF-α in LPS-stimulated macrophages at only 0.1 mg/mL). PTGG was conjugated to proteins via a one-pot process; molar mass- and grafting density-matched PTGG-lysozyme conjugates were superior to their PEG analogues in terms of enzyme activity and stability against freeze-drying or oxidation; the latter is due to sacrificial oxidation of methionine-mimetic PTGG chains. Both in mice and rats, PTGG-ovalbumin displayed circulation half-lives up to twice as long as PEG-ovalbumin, but most importantly─and differently from PEG─without any associated ABC effect seen either in the time dependency of blood concentration, in the liver/splenic accumulation, or in antipolymer IgM/IgG titers. Furthermore, similar pharmacokinetic results were obtained with PTGGylated/PEGylated liposomal nanocarriers. PTGG's 'active-stealth' character therefore makes it a highly promising alternative to PEG for conjugation to biologics or nanocarriers.

Mechanistic Modeling of the Effect of Recombinant Human Hyaluronidase (rHuPH20) on Subcutaneous Delivery of Cetuximab in Rats.

PURPOSE: To evaluate the duration of effect of rHuPH20 on SC absorption of cetuximab and to develop a mechanistic pharmacokinetic model linking the kinetics of rHuPH20 action with hyaluronan (HA) homeostasis and absorption of cetuximab from the SC space. METHODS: Serum pharmacokinetics of cetuximab was evaluated after IV and SC dosing at 0.4 and 10 mg/kg (control groups). In test groups, SC cetuximab was administered simultaneously with rHuPH20 (Co-Injection) or 12 h after injection of rHuPH20 (Pre-Injection). Mechanistic pharmacokinetic model was developed to simultaneously capture cetuximab kinetics in all groups. RESULTS: Administration of rHuPH20 resulted in a faster absorption of cetuximab; the difference between co-injection and pre-injection groups appeared to be dependent on the dose level. The model combined three major components: kinetics of rHuPH20 at SC site; HA homeostasis and its disruption by rHuPH20; and cetuximab systemic disposition and the effect of HA disruption on cetuximab SC absorption. The model provided good description of experimental data obtained in this study and collected previously. CONCLUSIONS: Proposed model can serve as a potential translational framework for capturing the effect of rHuPH20 across multiple preclinical species and in human studies and can be used for optimization of SC delivery of biotherapeutics.

Vitamin D Metabolism Gene Polymorphisms and Their Associated Disorders: A Literature Review.

BACKGROUND: Vitamin D is a fat-soluble vitamin, and it is a potential key factor in maintaining a healthy status. Various observational studies have reported the association between vitamin D deficiency and an elevated risk of osteoporosis, cardiovascular disease, diabetes mellitus, and certain types of cancer. The number of studies that investigates the genetic determinants of vitamin D hydroxy metabolism has been growing. Still, its association with the genetic variants remains unclear, particularly those genes related to vitamin D metabolism. AIMS: This work is a comprehensive review of available evidence of the effect of genetic variants on vitamin D metabolism and their impact on vitamin D status in the human body, disorders including coronavirus disease 2019 infection, and its importance for clinical investigators and public health. RESULTS: Genome-wide association studies and candidate gene studies show that genetic factors are influencing the circulating levels of vitamin D. These genetic changes are implicated in various pathways of vitamin D, such as metabolism and transport. It is also involved in the formation of the ternary complex (vitamin D receptor - retinoid receptor - transcription factor II B). CONCLUSION: Linkage studies may fail to identify replicated genetic architecture of vitD metabolism. Genome-wide association studies and the candidate gene approach have shown reproducible influences of gene control on vitD status.

A validated LC-MS/MS method for the quantitation of cefazolin in human adipose tissue: Application of EMR-Lipid sorbent as an efficient sample clean-up before mass spectrometric analyses.

A novel, simple, rapid, and sensitive high-performance liquid chromatography-tandem mass spectrometry method was developed to determine cefazolin concentrations in human adipose tissue. Sample preparation was performed by protein precipitation followed by using Captiva EMR-Lipid plates. The mobile phase consisted of 5 mM ammonium formate and 0.1% formic acid in water and 0.1% formic acid in ACN, and was pumped through a Synergi Fusion-RP column with a gradient elution program at a flow rate of 0.3 mL/min. The mass spectrometer was operated in a positive ion mode. Cloxacillin was used as an internal standard due to the observed cross-signal contribution between cefazolin and 13C2,15N-cefazolin. The method was validated according to the FDA and EMA guidelines and passed all the acceptance criteria. The calibration range was 0.05-50 µg/mL in adipose tissue homogenate (0.15-150 µg/g in adipose tissue), precision CV < 4.5%, accuracy within 93.1-100.4%. The carry-over was negligible, recovery of the method was high, and no significant matrix effect was present. Rat subcutaneous adipose tissue was demonstrated to be a suitable surrogate matrix for human adipose tissue. The validated method was successfully applied in a pilot pharmacokinetic study and will further be used in a large cohort of non-obese and obese patients dosed prophylactically with cefazolin before surgeries.

Effects of Overexpression of Fibroblast Growth Factor 15/19 on Hepatic Drug Metabolizing Enzymes.

Fibroblast growth factors 15 (FGF15) and 19 (FGF19) are endocrine growth factors that play an important role in maintaining bile acid homeostasis. FGF15/19-based therapies are currently being tested in clinical trials for the treatment of nonalcoholic steatohepatitis and cholestatic liver diseases. To determine the physiologic impact of long-term elevations of FGF15/19, a transgenic mouse model with overexpression of Fgf15 (Fgf15 Tg) was used in the current study. The RNA sequencing (RNA-seq) analysis revealed elevations of the expression of several genes encoding phase I drug metabolizing enzymes (DMEs), including Cyp2b10 and Cyp3a11, in Fgf15 Tg mice. We found that the induction of several Cyp2b isoforms resulted in increased function of CYP2B in microsomal metabolism and pharmacokinetics studies. Because the CYP2B family is known to be induced by constitutive androstane receptor (CAR), to determine the role of CAR in the observed inductions, we crossed Fgf15 Tg mice with CAR knockout mice and found that CAR played a minor role in the observed alterations in DME expression. Interestingly, we found that the overexpression of Fgf15 in male mice resulted in a phenotypical switch from the male hepatic expression pattern of DMEs to that of female mice. Differences in secretion of growth hormone (GH) between male and female mice are known to drive sexually dimorphic, STAT5b-dependent expression patterns of hepatic genes. We found that male Fgf15 Tg mice presented with many features similar to GH deficiency, including lowered body length and weight, Igf-1 and Igfals expression, and STAT5 signaling. SIGNIFICANCE STATEMENT: The overexpression of Fgf15 in mice causes an alteration in DMEs at the mRNA, protein, and functional levels, which is not entirely due to CAR activation but associated with lower GH signaling.

Prediction of Individual Analgesic Response to Intravenous Lidocaine in Painful Diabetic Peripheral Neuropathy: A Randomized, Placebo-controlled, Crossover Trial.

OBJECTIVES: Intravenous lidocaine can alleviate painful diabetic peripheral neuropathy (DPN) in some patients. Whether quantitative sensory testing (QST) can identify treatment responders has not been prospectively tested. MATERIALS AND METHODS: This was a prospective, randomized, double-blind, crossover, placebo-controlled trial comparing intravenous lidocaine to normal saline (placebo) for painful DPN. Thirty-four participants with painful DPN were enrolled and administered intravenous lidocaine (5 mg/kg ideal body weight) or placebo as a 40-minute infusion, after a battery of QST parameters were tested on the dorsal foot, with a 3-week washout period between infusions. RESULTS: Thirty-one participants completed both study sessions and were included in the final analysis. Lidocaine resulted in a 51% pain reduction 60 to 120 minutes after infusion initiation, as assessed on a 0 to 10 numerical rating scale, while placebo resulted in a 33.5% pain reduction (difference=17.6%, 95% confidence interval [CI], 1.9%-33.3%, P=0.03). Neither mechanical pain threshold, heat pain threshold, or any of the other measured QST parameters predicted the response to treatment. Lidocaine administration reduced mean Neuropathic Pain Symptom Inventory paresthesia/dysesthesia scores when compared with placebo by 1.29 points (95% CI, -2.03 to -0.55, P=0.001), and paroxysmal pain scores by 0.84 points (95% CI, -1.62 to -0.56, P=0.04), without significant changes in burning, pressing or evoked pain subscores. DISCUSSION: While some participants reported therapeutic benefit from lidocaine administration, QST measures alone were not predictive of response to treatment. Further studies, powered to test more complex phenotypic interactions, are required to identify reliable predictors of response to pharmacotherapy in patients with DPN.