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.

The (+)-Brevipolide H Displays Anticancer Activity against Human Castration-Resistant Prostate Cancer: The Role of Oxidative Stress and Akt/mTOR/p70S6K-Dependent Pathways in G1 Checkpoint Arrest and Apoptosis.

Because conventional chemotherapy is not sufficiently effective against prostate cancer, various examinations have been performed to identify anticancer activity of naturally occurring components and their mechanisms of action. The (+)-brevipolide H, an α-pyrone-based natural compound, induced potent and long-term anticancer effects in human castration-resistant prostate cancer (CRPC) PC-3 cells. Flow cytofluorometric analysis with propidium iodide staining showed (+)-brevipolide H-induced G1 arrest of cell cycle and subsequent apoptosis through induction of caspase cascades. Since Akt/mTOR pathway has been well substantiated in participating in cell cycle progression in G1 phase, its signaling and downstream regulators were examined. Consequently, (+)-brevipolide H inhibited the signaling pathway of Akt/mTOR/p70S6K. The c-Myc inhibition and downregulation of G1 phase cyclins were also attributed to (+)-brevipolide H action. Overexpression of myristoylated Akt significantly rescued mTOR/p70S6K and downstream signaling under (+)-brevipolide H treatment. ROS and Ca2+, two key mediators in regulating intracellular signaling, were determined, showing that (+)-brevipolide H interactively induced ROS production and an increase of intracellular Ca2+ levels. The (+)-Brevipolide H also induced the downregulation of anti-apoptotic Bcl-2 family proteins (Bcl-2 and Bcl-xL) and loss of mitochondrial membrane potential, indicating the contribution of mitochondrial dysfunction to apoptosis. In conclusion, the data suggest that (+)-brevipolide H displays anticancer activity through crosstalk between ROS production and intracellular Ca2+ mobilization. In addition, suppression of Akt/mTOR/p70S6K pathway associated with downregulation of G1 phase cyclins contributes to (+)-brevipolide H-mediated anticancer activity, which ultimately causes mitochondrial dysfunction and cell apoptosis. The data also support the biological significance and, possibly, clinically important development of natural product-based anticancer approaches.

[effect of treatment from the lung and treatment from the intestine on vasoactive intestinal peptide contents of ulcerative colitis rats: a comparison study].

OBJECTIVE: To observe effects of treatment from the lung and treatment from the intestine on the level of vasoactive intestinal peptide (VIP) in the lung and intestine of ulcerative colitis (UC) rats. METHODS: The UC rat model was established in 52 rats by using rabbit intestine mucosa tissue allergen combined TNBS-ethanol model (with the model successful rate of 78.0%). Eight rats randomly selected from 40 successfully modeled rats and 8 of 16 rats from the normal group were recruited as the model group and the normal control group before intervention (at week 0). The rest 32 successfully modeled rats were randomly divided into the model group, the Western medicine treatment group (salazosulfapyridine), the treatment from lung group (Huangqi Jiegeng Decoction), and the treatment from intestine group (Huangqi Huanglian Decoction), 8 in each group. Rats in each treatment group were administered with corresponding medication 8 times the dose of a 60 kg adult human. Another 8 normal rats were recruited as the normal group. Equal volume of pure water was given to rats in the model group and the normal group by gastrog avage, once per day. Contents of VIP in the lung tissue and the intestinal tissue were detected at week 0 and 4 after 4-week consecutive intervention. Pathomorphological changes of the lung tissue and the colon tissue were observed under light microscope. RESULTS: Compared with the normal control group at week 0, evenly distributed diffuse inflammation could be seen in the pulmonary interstitial tissue; the bronchial wall was thickened; a huge amount of infiltration surrounded bronchi and blood vessels; a large area of necrosis of intestinal mucosa and inflammatory cell infiltration could also be seen in the model group. Pathological injuries of the lung and the colon were more alleviated in each treatment group than in the model group at the same time point. Compared with the normal control group at the same time point, VIP contents in the lung tissue significantly decreased in the model group at the end of week 4 (P<0.05); VIP contents in the colon tissue significantly increased in the model group at the end of week 0 and 4 (P <0.05). Compared with the model group, VIP contents in the lung tissue significantly increased in the Western medicine treatment group and the treatment from lung group at the end of week 4 (P<0.01); VIP contents in the colon tissue significantly decreased in the treatment from lung group and the treatment from intestine group (P<0.05, P<0.01). CONCLUSION: Treatment from the lung and treatment from the intestine showed predominant advantage in improving local inflammation of the lung and the intestinal tract, alleviating pathological injuries, promoting repair of injuries through regulating VIP contents in the lung tissue and the colon tissue.

[Changes of inherent immune response and acquired immune response in the tung tissue and the intestinal tissue of ulcerative colitis rats and the intervention of Chinese compound: an experimental research].

OBJECTIVE: To explore Chinese medical theory of Fei and Dachang being interior-exteriorly correlated by observing changes of inherent immune response and acquired immune response in the lung tissue and the intestinal tissue of ulcerative colitis (UC) model rats and the intervention of Chinese compounds (CM). METHODS: Seventy rats were randomly divided into 5 groups, i.e., the normal control group (n = 10), the model group (n = 15), the treatment 1 group (n = 15, treated from Fei), the treatment 2 group (n = 15, treated from the intestine), and the Western medicine (WM) group [n = 15, treated with Sulfasalazine (SASP). Except those in the normal control group, the UC rat model was prepared by allergizing colon mucosa combined with TNBS-alcohol (50%) enema, and then intervened by medication (treated with CM complex prescription of treatment from lung, CM complex prescription of treatment from intestine, and SASP). After intragastric administration for 4 weeks, rats were sacrificed and samples taken. The expression of tumor necrosis factor α (TNF-α) and IL-8 contents in the lung tissue, the intestinal tissue, and the serum were detected by radioimmunoassay. Serum MedCAM-1 contents were detected using ELISA. Changes of the expression of Toll-like receptor 4 (TLR4), nuclear factor κB (NF-κB), neutrophil migration inhibition factor (MIF), mucosal addressin cell adhesion molecule-1 (MadCAM-1) mRNA in the lung tissue and the intestinal tissue were detected by real time PCR. RESULTS: Compared with the normal control group, the expression levels of TNF-α, TLR4 mRNA, IL-8, MIF mR- NA, and MadCAM-1 mRNA obviously increased in the model group (P < 0.01). Compared with the model group, the expression levels of TNF-α, TLR4 mRNA, IL-8, MIF mRNA, and MadCAM-1 mRNA obviously decreased in the treatment 1 and 2 groups (P < 0.01). The expression of MadCAM-1 mRNA in the intestinal tissue was obviously higher in the model group than in the normal control group (P < 0.01), while the expressions of TNF-α and NF-κB mRNA was obviously lower in the model group than in the normal control group (P < 0.05, P < 0.01). Compared with the model group, the expression of MadCAM-1 mRNA all significantly deceased in each treatment group (P < 0.05, P < 0.01). Serum TNF-α contents were higher in the model group than in the normal control group (P < 0.05). Compared with the model group, serum TNF-α contents could be lowered in the treatment 1 and 2 groups (P < 0.05, P < 0.01). CONCLUSIONS: The main mechanisms of the intestinal injury in this UC model might be related with activation of acquired immune response, accompanied with lowered functions of inherent immune response. The main mechanisms of the lung injury in this UC model might be related acquired immune response and inherent immune response. Treatment from Fei and treatment from Dachang both could obviously improve the immunodissonance of Fei and Dachang, indicating the special relation between the lung tissue and the intestinal tissue, thus providing experimental evidence for Chinese medical theory of Fei and Dachang being interior-exteriorly correlated.

[Exploration of the theory of "Fei and Dachang being interior-exteriorly related" from observing changes of inflammatory cytokines and oxygen free radicals in the lung tissue of ulcerative colitis rats].

OBJECTIVE: To explore the theory of "Fei and Dachang being interior-exteriorly related" and the pathogenesis of lung injury by observing changes of inflammatory cytokines and oxygen free radicals in ulcerative colitis (UC) rats. METHODS: Totally 50 healthy male Wistar rats were randomly divided into two groups, the normal control group and the model group, 25 rats in each group. The UC model was established by allergizing colon mucosa combined with TNBS-alcohol (50%) enema. Another 25 rats were recruited as the normal control group. At week 2 and 4 after modeling, the pathomorphological changes of the lung were observed. Furthermore, the contents of tumor necrosis factor alpha (TNF-alpha) and IL-1beta were determined by ELISA. The activities of superoxide dismutase (SOD) and malondialdehyde (MDA) were evaluated with colorimetry. RESULTS: Compared with the normal control group, the pathomorphology of the lung tissue in the model group appeared abnormal at week 2 and 4. Compared with the normal control group, levels of TNF-alpha, IL-1beta, and MDA in the lung tissue significantly increased in the model group (P < 0. 01) and the activities of SOD significantly decreased (P < 0.05, P < 0.01). CONCLUSION: TNF-alpha, IL-1beta, SOD, and MDA might be common material bases for the large intestine involved in lung disease of UC patients, thus providing a modern scientific basis for the theory of Fei and Dachang being interior-exteriorly related.

A validated LC-MS/MS method for simultaneous quantitation of piperacillin, cefazolin, and cefoxitin in rat plasma and twelve tissues.

BACKGROUND: The investigation of drug disposition in tissues is critical to improving dosing strategy and maximizing treatment effectiveness, yet developing a multi-tissue bioanalytical method could be challenging due to the differences among various matrices. Herein, we developed an LC-MS/MS method tailored for the quantitation of piperacillin (PIP), cefazolin (CFZ), and cefoxitin (CFX) in rat plasma and 12 tissues, accompanied by validation data for each matrix according to the FDA and EMA guidelines. RESULTS: The method required only a small sample volume (5 µL plasma or 50-100 µL tissue homogenates) and a relatively simple protocol for simultaneous quantitation of PIP, CFZ, and CFX within different biological matrices. Mobile phase A was composed of 5 mM ammonium formate and 0.1 % formic acid in water, while mobile phase B contained 0.1 % formic acid in acetonitrile. The mobile phase was pumped through a Synergi Fusion-RP column equipped with a guard column with a gradient elution program at a 0.3 mL/min flow rate. The mass spectrometer was operated in positive ionization mode (ESI+) using multiple reaction monitoring. SIGNIFICANCE: The validated method has been successfully applied to quantify PIP, CFZ, and CFX from the plasma and tissue samples collected in a pilot rat study and will further be used in a large pharmacokinetic study. To our knowledge, this is also the first report presenting long-term, freeze-thaw, and autosampler stability data for PIP, CFZ, and CFX in rat plasma and multiple tissues.

Delivery of sorafenib by myofibroblast-targeted nanoparticles for the treatment of renal fibrosis.

Fibrosis is an excessive accumulation of the extracellular matrix within solid organs in response to injury and a common pathway that leads functional failure. No clinically approved agent is available to reverse or even prevent this process. Herein, we report a nanotechnology-based approach that utilizes a drug carrier to deliver a therapeutic cargo specifically to fibrotic kidneys, thereby improving the antifibrotic effect of the drug and reducing systemic toxicity. We first adopted in vitro-in vivo combinatorial phage display technology to identify peptide ligands that target myofibroblasts in mouse unilateral ureteral obstruction (UUO)-induced fibrotic kidneys. We then engineered lipid-coated poly(lactic-co-glycolic acid) nanoparticles (NPs) with fibrotic kidney-homing peptides on the surface and sorafenib, a potent antineoplastic multikinase inhibitor, encapsulated in the core. Sorafenib loaded in the myofibroblast-targeted NPs significantly reduced the infiltration of α-smooth muscle actin-expressing myofibroblasts and deposition of collagen I in UUO-treated kidneys and enhanced renal plasma flow measured by Technetium-99m mercaptoacetyltriglycine scintigraphy. This study demonstrates the therapeutic potential of the newly identified peptide fragments as anchors to target myofibroblasts and represents a strategic advance for selective delivery of sorafenib to treat renal fibrosis. SIGNIFICANCE STATEMENT: Renal fibrosis is a pathological feature accounting for the majority of issues in chronic kidney disease (CKD), which may progress to end-stage renal disease (ESRD). This manuscript describes a myofibroblast-targeting drug delivery system modified with phage-displayed fibrotic kidney-homing peptides. By loading the myofibroblast-targeting nanoparticles (NPs) with sorafenib, a multikinase inhibitor, the NPs could suppress collagen synthesis in cultured human myofibroblasts. When given intravenously to mice with UUO-induced renal fibrosis, sorafenib loaded in myofibroblast-targeting NPs significantly ameliorated renal fibrosis. This approach provides an efficient therapeutic option to renal fibrosis. The myofibroblast-targeting peptide ligands and nanoscale drug carriers may be translated into clinical application in the future.

[Crohn disease in rats induced by different concentrations of trinitrobenzenesulfonic acid and ethanol].

OBJECTIVE: To induce Crohn disease in rats by intraluminal instillations of different concentrations of 2,4,6-trinitrobenzenesulfonic acid (TNBS) and ethanol. METHODS: Crohn disease in rats was induced with enema containing TNBS and 50% ethanol with volume ratio of 2:1 (experimental group 1) or 1:1 (experimental group 2), or solution containing TNBS and anhydrous ethanol with volume ratio of 2:1 (experimental group 3) or 1:1 (experimental group 4). Equivalent volume of normal saline was used to set as the normal saline control, and rats without any treatment were set as the normal control group. The rats were killed at various time points (3, 7, 14 and 21 d) respectively. Colonic inflammation and damage were assessed microscopically and histologically. RESULTS: In the colon of rats in the experimental group 3, discontinuous erosion, ulceration and infiltration of neutrophils occurred after one week; pebble sign and even segmental inflammation appeared on day 14. On day 21, it appeared improvement in the colon tissue and obviously thickened bowel wall, but the inflammation was easily observed under the light microscope. Experimental group 1 was similar to experimental group 3 in appearance of the colon on days 3 and 7; on day 14, colonic inflammation and damage were improved as compared with the experimental group 3, but there were obvious individual differences in histological findings among rats in group 1. In the experimental group 2, the intestinal wall turned to be normal on day 14. In the experimental group 4, there were high mortality and extensive damage of colon tissues, and the pathological characteristics were quite different from Crohn disease in humans. CONCLUSION: The characteristics of the rat model of Crohn disease induced with a enema containing TNBS and anhydrous ethanol with volume ratio of 2:1 are similar to the clinical features of human Crohn disease, including typical pathological characteristics and long duration of inflammation. It may be an ideal experimental model for studying pathogenesis of Crohn disease and for evaluating treatment effects.

Phosphodiesterase Type 5 (PDE5) Inhibitors Sensitize Topoisomerase II Inhibitors in Killing Prostate Cancer Through PDE5-Independent Impairment of HR and NHEJ DNA Repair Systems.

Human castration-resistant prostate cancer (CRPC) is a significant target of clinical research. The use of DNA-damaging agents has a long history in cancer chemotherapy but is limited by their toxicities. The combination with a safer drug can be a strategy in reducing dosage and toxicity while increasing anticancer activity in CRPC treatment. Phosphodiesterase type 5 (PDE5) inhibitors are used to treat erectile dysfunction through the selective inhibition of PDE5 that is responsible for cGMP degradation in the corpus cavernosum. Several studies have reported that PDE5 inhibitors display protective effect against doxorubicin-induced cardiotoxicity. The combinatory treatment of CRPC with doxorubicin and PDE5 inhibitors has been studied accordingly. The data demonstrated that sildenafil or vardenafil (two structure-related PDE5 inhibitors) but not tadalafil (structure-unrelated to sildenafil) sensitized doxorubicin-induced apoptosis in CRPC cells with deteriorating the down-regulation of anti-apoptotic Bcl-2 family members, including Bcl-xL and Mcl-1, and amplifying caspase activation. Homologous recombination (HR) and non-homologous end joining (NHEJ) DNA repair systems were inhibited in the apoptotic sensitization through detection of nuclear foci formation of Rad51 and DNA end-binding of Ku80. PDE5 knockdown to mimic the exposure to PDE5 inhibitors did not reproduce apoptotic sensitization, suggesting a PDE5-independent mechanism. Not only doxorubicin, sildenafil combined with other inhibitors of topoisomerase II but not topoisomerase I also triggered apoptotic sensitization. In conclusion, the data suggest that sildenafil and vardenafil induce PDE5-independent apoptotic sensitization to doxorubicin (or other topoisomerase II inhibitors) through impairment of both HR and NHEJ repair systems that are evident by a decrease of nuclear Rad51 levels and their foci formation in the nucleus, and an inhibition of Ku80 DNA end-binding capability. The combinatory treatment may enable an important strategy for anti-CRPC development.

Reactivation of endogenous retroviral elements via treatment with DNMT- and HDAC-inhibitors.

Inhibitors of DNA methyltransferases (DNMTis) or histone deacetylases (HDACis) are epigenetic drugs which are investigated since decades. Several have been approved and are applied in the treatment of hematopoietic and lymphatic malignancies, although their mode of action has not been fully understood. Two recent findings improved mechanistic insights: i) activation of human endogenous retroviral elements (HERVs) with concomitant synthesis of double-stranded RNAs (dsRNAs), and ii) massive activation of promoters from long terminal repeats (LTRs) which originated from past HERV invasions. These dsRNAs activate an antiviral response pathway followed by apoptosis. LTR promoter activation leads to synthesis of non-annotated transcripts potentially encoding novel or cryptic proteins. Here, we discuss the current knowledge of the molecular effects exerted by epigenetic drugs with a focus on DNMTis and HDACis. We highlight the role in LTR activation and provide novel data from both in vitro and in vivo epigenetic drug treatment.