Double-Emulsion Copolyester Microcapsules for Sustained Intraperitoneal Release of Carboplatin.

Despite on-going medical advances, ovarian cancer survival rates have stagnated. In order to improve IP delivery of platinum-based antineoplastics, we aimed to develop a sustained drug delivery system for carboplatin (CPt). Toward this aim, we pursued a double emulsion process for obtaining CPt-loaded microcapsules composed of poly(ethylene terephthalate-ethylene dilinoleate) (PET-DLA) copolymer. We were able to obtain PET-DLA microspheres in the targeted size range of 10-25 µm (median: 18.5 µm), to reduce intraperitoneal clearance by phagocytosis and lymphoid transit. Empty microspheres showed the lack of toxicity in vitro. The double emulsion process yielded 2.5% w/w CPt loading and obtained microcapsules exhibited sustained (>20 day) zero-order release. The encapsulated CPt was confirmed to be bioavailable, as the microcapsules demonstrated efficacy against human ovarian adenocarcinoma (SK-OV-3) cells in vitro. Following intraperitoneal injection in mice, we did not observe adhesions, only mild, clinically-insignificant, local inflammatory response. Tissue platinum levels, monitored over 14 days using atomic absorption spectroscopy, revealed low burst and reduced systemic uptake (plasma, kidney), as compared to neat carboplatin injection. Overall, the results demonstrate the potential of the developed microencapsulation system for long-term intraperitoneal sustained release of carboplatin for the treatment of ovarian cancer.

Expression of clinically relevant drug-metabolizing enzymes along the human intestine and their correlation to drug transporters and nuclear receptors: An intra-subject analysis.

The oral bioavailability of many drugs is highly influenced not only by hepatic but also by intestinal biotransformation. To estimate the impact of intestinal phase I and II metabolism on oral drug absorption, knowledge on the expression levels of the respective enzymes is an essential prerequisite. In addition, the potential interplay of metabolism and transport contributes to drug disposition. Both mechanisms may be subjected to coordinative regulation by nuclear receptors, leading to unwanted drug-drug interactions due to induction of intestinal metabolism and transport. Thus, it was the aim of this study to comprehensively analyse the regional expression of clinically relevant phase I and II enzymes along the entire human intestine and to correlate these data to expression data of drug transporters and nuclear receptors of pharmacokinetic relevance. Gene expression of 11 drug-metabolizing enzymes (CYP2B6, 2C8, 2C9, 2C19, 2D6, 3A4, 3A5, SULT1A, UGT1A, UGT2B7, UGT2B15) was studied in duodenum, jejunum, ileum and colon from six organ donors by real-time RT-PCR. Enzyme expression was correlated with expression data of the nuclear receptors PXR, CAR and FXR as well as drug transporters observed in the same cohort. Intestinal expression of all studied metabolizing enzymes was significantly higher in the small intestine compared to colonic tissue. CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, SULT1A, UGT1A and UGT2B7 expression increased from the duodenum to jejunum but was markedly lower in the ileum. In the small intestine, that is, the predominant site of drug absorption, the highest expression has been observed for CYP3A4, CYP2C9, SULT1A and UGT1A. In addition, significant correlations were found between several enzymes and PXR as well as ABC transporters in the small intestine. In conclusion, the observed substantial site-dependent intestinal expression of several enzymes may explain regional differences in intestinal drug absorption. The detected correlations between intestinal enzymes, transporters and nuclear receptors provide indirect evidence for their coordinative expression, regulation and function in the human small intestine.

Protein Abundance of Clinically Relevant Drug Transporters in the Human Liver and Intestine: A Comparative Analysis in Paired Tissue Specimens.

Bioavailability of orally administered drugs is partly determined by function of drug transporters in the liver and intestine. Therefore, we explored adenosine triphosphate-binding cassette (ABC) and solute carriers family transporters expression (quantitative polymerase chain reaction) and protein abundance (liquid chromatography tandem mass spectrometry (LC-MS/MS)) in human liver and duodenum, jejunum, ileum, and colon in paired tissue specimens from nine organ donors. The transporter proteins were detected in the liver (permeability-glycoprotein (P-gp), multidrug resistance protein (MRP)2, MRP3, breast cancer resistance protein (BCRP), organic anion-transporting polypeptide (OATP)1B1, OATP1B3, OATP2B1, organic cation transporter (OCT)1, OCT3, organic anion transporter 2, Na+-taurocholate cotransporting polypeptide, monocarboxylate transporter (MCT)1, and multidrug and toxin extrusion 1) and the intestine (P-gp, multidrug-resistance protein (MRP)2, MRP3, MRP4, BCRP, OATP2B1, OCT1, apical sodium-bile acid transporter (only ileum), MCT1, and peptide transporter (PEPT1)). Significantly higher hepatic gene expression and protein abundance of ABCC2/MRP2, SLC22A1/OCT1, and SLCO2B1/OATP2B1 were found, as compared to all intestinal segments. No correlations between hepatic and small intestinal protein levels were observed. These observations provide a description of drug transporters distribution without the impact of interindividual variability bias and may help in construction of superior physiologically based pharmacokinetic and humanized animal models.

Protein Abundance of Clinically Relevant Drug-Metabolizing Enzymes in the Human Liver and Intestine: A Comparative Analysis in Paired Tissue Specimens.

This work revises and complements existing findings on the distribution of drug-metabolizing enzymes in the first-pass effect organs. We explored gene expression (quantitative polymerase chain reaction) and protein abundance (liquid chromatography/ tandem mass spectrometry) of CYP1A2, CYP2B6, CYP2C8/9/19, CYP2D6, CYP2E1, CYP3A4/5, UGT1A1/3, UGT2B7/15 in the liver, duodenum, jejunum, ileum, and colon in paired tissues from nine organ donors. All proteins were detected in the liver, but in the intestine CYP2C9/19, CYP2D6, CYP3A4/5, UGT1A1/3, and UGT2B7 were found. CYP3A4 showed comparable abundance in the liver and jejunum, whereas other enzymes were markedly higher in the hepatic tissue. Nearly all detected enzymes showed their highest abundance in the jejunum. Significant correlations between mRNA and protein levels in liver or intestine were found for most enzymes. CYP3A4 and CYP3A5 protein abundance, but not other enzymes, were significantly correlated in the liver and the small intestine. Our data may contribute to an improved understanding of hepatic and intestinal drug metabolism.

Nuclear factor E2-related factor-2 (Nrf2) expression and regulation in male reproductive tract.

BACKGROUND: Nuclear factor E2-related factor-2 (Nrf2, Nfe2l2) plays an important, protective role in many tissues. However, information on molecular mechanisms of detoxification and drug metabolism regulated by Nrf2/NRF2 in testis and epididymis is scarce, but it may help to better characterize the function of blood-testis and epididymis barriers. METHODS: Constitutive gene expression was analyzed by real time PCR with TaqMan Assay using ΔCT-method. Additionally, gene expression after treatment with oltipraz- specific Nrf2 inducer was evaluated using ΔΔCT-method. Cellular localization of the Nrf2 was visualized by immunohistochemical reaction. RESULTS: The study showed that Nrf2 mRNA level in rat epididymis was higher than in testis. In human tissues, both testis and epididymis demonstrated similar expression levels of NRF2. Immunohistochemical analysis revealed NRF2/Nrf2 protein expression in testis and epididymis, which in the case of testis was dependant on spermatogenesis stage. Both in human and rat tissues constitutive expression of NQO1/Nqo1 was slightly higher in epididymis than in testis. Other Nrf2 regulated genes: GCLC/Gclc and UGT1A6/Ugt1a6 showed different ratios of testis/epididymis/liver expression levels. Treatment with oltipraz (Nrf2 inducer) resulted in significant induction of Nrf2 expression solely in corpus of epididymis. CONCLUSIONS: Components of the Nrf2/NRF2 system along with coordinated genes are expressed in testis and epididymis. Moreover, some interspecies differences between rat and human were observed, which may impact extrapolation of experimental data into clinical findings. Studies on animal model showed that corpus of epididymis is the most responsive part of the male reproductive tract to oltipraz exposure at the gene expression level.

The role of aryl hydrocarbon receptor (AhR) in the pathology of pleomorphic adenoma in parotid gland.

OBJECTIVES: Pleomorphic adenoma (benign mixed tumor) is one of the most common salivary gland tumors. However, molecular mechanisms implicated in its development are not entirely defined. Therefore, the study aimed at definition of aryl hydrocarbon receptor (AhR) involvement in pleomorphic adenoma pathology, as the AhR controlled gene system was documented to play a role in development of various human tumors. DESIGN: The study was carried out in pleomorphic adenoma and control parotid gland tissues where gene expression of AHR, AhR nuclear translocator (ARNT), AhR repressor (AHRR), as well as AhR controlled genes: CYP1A1 and CYP1B1, at mRNA and protein (immunohistochemistry) levels were studied. Functional evaluation of AhR system was evaluated in HSY cells (human parotid gland adenocarcinoma cells) using 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as AhR specific inducer. RESULTS: Pleomorphic adenoma specimens showed cytoplasmic and nuclear AhR expression in epithelial cells as well as in mesenchymal cells. In parotid gland AhR was expressed in cytoplasm of duct cells. Quantitative expression at mRNA level showed significantly higher expression of AHR, ARNT and CYP1B1, and comparable levels of CYP1A1 in pleomorphic adenoma tissue in comparison to healthy parotid gland. The HSY cell study revealed significantly higher expression level of AHRR in HSY as compared with MCF-7 cells (human breast adenocarcinoma cell line used as reference). Upon TCDD stimulation a drop in AHRR level in HSY cells and an increase in MCF-7 cells were observed. The HSY and MCF-7 cell proliferation rate (measured by WST-1 test) was not affected by TCDD. CONCLUSIONS: Summarizing both in vitro and in vivo observations it can be stated that AhR system may play a role in the pathology of pleomorphic adenoma.

Protein abundance of clinically relevant multidrug transporters along the entire length of the human intestine.

Intestinal transporters are crucial determinants in the oral absorption of many drugs. We therefore studied the mRNA expression (N = 33) and absolute protein content (N = 10) of clinically relevant transporters in healthy epithelium of the duodenum, the proximal and distal jejunum and ileum, and the ascending, transversal, descending, and sigmoidal colon of six organ donors (24-54 years). In the small intestine, the abundance of nearly all studied proteins ranged between 0.2 and 1.6 pmol/mg with the exception of those of OCT3 (<0.1 pmol/mg) and PEPT1 (2.6-4.9 pmol/mg) that accounted for ∼50% of all measured transporters. OATP1A2 was not detected in any intestinal segment. ABCB1, ABCG2, PEPT1, and ASBT were significantly more abundant in jejunum and ileum than in colon. In contrast to this, the level of expression of ABCC2, ABCC3, and OCT3 was found to be highest in colon. Site-dependent differences in the levels of gene and protein expression were observed for ABCB1 and ASBT. Significant correlations between mRNA and protein levels have been found for ABCG2, ASBT, OCT3, and PEPT1 in the small intestine. Our data provide further physiological pieces of the puzzle required to predict intestinal drug absorption in humans.

Expression and functional regulation of the nuclear receptors AHR, PXR, and CAR, and the transcription factor Nrf2 in rat parotid gland.

Nuclear receptors and transcription factors regulate the functions of many genes involved in cellular physiology and pathology (e.g. tumorigenesis and autoimmune diseases). The present study was performed to define the expression and the regulation of aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), constitutive androstane receptor (CAR), and nuclear factor E2-related factor 2 (Nrf2) in the rat parotid gland. Constitutive expression, as well as expression after stimulation with specific inducers for AhR [2,3,7,8-tetrachloro-dibenzylo-p-dioxin (TCDD)], Nrf2(oltipraz), PXR (dexamethasone), and CAR (phenobarbital), was evaluated using the quantitative PCR. Cellular localization of the nuclear receptors and the transcription factor was visualized by immunohistochemical staining. The study revealed constitutive expression of AhR as well as Nrf2, and their induction by TCDD andoltipraz, respectively. Immunohistochemical analysis revealed constitutive, predominantly cytoplasmic, expression of the AhR receptor, especially in interlobular striated duct cells, with nuclear shift upon exposure to TCDD. Inducible expression of Nfr2 was found mainly in the cytoplasm of intralobular striated duct cells. Constitutive expression of PXR and CAR was not found. Bearing in mind the involvement of AhR and Nrf2 in the regulation of many genes, it seems that these factors may play also a role in salivary gland physiology and pathology.

Antibacterial performance of nanocrystallined titania confined in mesoporous silica nanotubes.

In this paper, we study synthesis and characteristics of mesoporous silica nanotubes modified by titanium dioxide, as well as their antimicrobial properties and influence on mitochondrial activity of mouse fibroblast L929. Nanocrystalized titania is confined in mesopores of silica nanotubes and its light activated antibacterial response is revealed. The analysis of the antibacterial effect on Escherichia coli. (ATCC 25922) shows strong enhancement during irradiation with the artificial visible and ultraviolet light in respect to the commercial catalyst and control sample free from the nanomaterials. In darkness, the mesoporous silica/titania nanostructures exhibited antibacterial activity dependent on the stirring speed of the suspension containing nanomaterials. Obtained micrograph proved internalization of the sample into the microorganism trough the cell membrane. The analysis of the mitochondrial activity and amount of lactate dehydrogenase released from mouse fibroblast cells L929 in the presence of the sample were determined with LDH and WST1 assays, respectively. The synthesized silica/titania antibacterial agent also exhibits pronounced photoinduced inactivation of the bacterial growth under the artificial visible and UV light irritation in respect to the commercial catalyst. Additionally, mesoporous silica/titania nanotubes were characterized in details by means of high resolution transmission electron microscopy (HR-TEM), XRD and BET Isotherm.

Analysis of common type 2 diabetes mellitus genetic risk factors in new-onset diabetes after transplantation in kidney transplant patients medicated with tacrolimus.

PURPOSE: New-onset diabetes after transplantation (NODAT) is a major complication after kidney transplantation. The risk factors for NODAT include the use of calcineurin inhibitors as part of the immunosuppressive regimen, among which tacrolimus has the most pronounced diabetogenic effect. Both NODAT and type 2 diabetes mellitus (T2DM) share several risk factors. Recent studies have identified a number of common genetic variants associated with increased risk of T2DM. Here we report the results of our study on the potential effect of single nucleotide polymorphisms (SNPs) previously associated with T2DM on the risk of NODAT in kidney transplant patients medicated with tacrolimus. METHODS: Seven SNPs in six genes known to increase the risk of T2DM in Caucasians were genotyped by means of TaqMan assays in 235 kidney transplant patients medicated with tacrolimus: rs4402960 and rs1470579 in IGF2BP2; rs1111875 in HHEX; rs10811661 upstream of CDKN2A/B; rs13266634 in SLC30A8; rs1801282 in PPARG; rs5215 in KCNJ11. The TCF7L2 rs7903146 SNP was also included in the multivariate analysis. RESULTS: None of the analyzed SNPs was significantly associated with the risk of NODAT. However, the IGF2BP2 rs4402960 T allele was present significantly more frequently among patients diagnosed with NODAT more than 2 weeks after transplantation (p = 0.048). Mean (± standard deviation) number of the analyzed alleles tended to be lower in patients without NODAT (6.19 ± 1.71) than in NODAT patients (6.58 ± 1.1.95; p = 0.09) and significantly lower compared to late-onset NODAT patients (7.03 ± 1.88; p = 0.018). Multivariate analysis confirmed the significance of 'diabetogenic' allele number in late-onset NODAT development [odds ratio (OR) 1.37, 95 % confidence interval (CI) 1.05-1.78; p = 0.017]. Additionally, individuals carrying >7 of the analyzed 'diabetogenic' alleles were at a significantly higher risk of NODAT (OR 2.17, 95 % CI 1.18-3.99; p = 0.015). CONCLUSIONS: Complex analysis of genotypes increasing the risk of diabetes may lead to the identification of NODAT susceptibility predictors.

Synthesis, dispersion, and cytocompatibility of graphene oxide and reduced graphene oxide.

The synthesis, characterization, and toxicity of graphene oxide and reduced graphene oxide are reported. Prior to the cytocompatibility tests the stability of the suspensions in a wide range of concentrations (3.125-100 µg/mL) of three different dispersants is studied. Polyethylene glycol (PEG), polyethylene glycol-polypropylene glycol-polyethylene glycol (Pluronic P123), and sodium deoxycholate (DOC) are investigated as the dispersants. The toxicity depends on the type of dispersant and concentration of the nanomaterials in the suspensions. Detailed analysis suggests that graphene oxide functionalized with PEG in the concentration range between 3125 µg/mL and 25 µg/mL exhibits the best biocompatibility with mice fibroblast cells (line L929).

Association of transcription factor 7-like 2 (TCF7L2) gene polymorphism with posttransplant diabetes mellitus in kidney transplant patients medicated with tacrolimus.

New onset posttransplant diabetes mellitus (PTDM) has a high incidence after kidney transplantation in patients medicated with tacrolimus. PTDM can adversely affect patient and graft survival. The pathophysiology of PTDM closely mimics type 2 diabetes mellitus (T2DM). One of the possible genetic factors predisposing individuals to PTDM might be a polymorphism in the transcription factor 7-like 2 gene (TCF7L2). This polymorphism has previously been associated with increased risk of T2DM in the general population. Therefore, the present study aimed to evaluate TCF7L2 polymorphisms in PTDM in kidney transplant patients medicated with tacrolimus. Non-diabetic kidney transplant patients medicated with tacrolimus (n = 234) were genotyped for the presence of TCF7L2 gene variants (rs12255372 and rs7903146) using TaqMan probes. Of the 234 patients, 66 patients had developed PTDM and 168 had not. Frequencies of the studied single nucleotide polymorphisms (SNPs) did not differ significantly between the study groups. Moreover, haplotype analyses failed to detect any associations between TCF7L2 haplotypes and PTDM. However, in late-onset PTDM (developed later that 2 weeks from transplantation), frequencies of the rs7903146 TT genotype and T minor allele were significantly increased compared to non-PTDM controls (17.9% vs. 5.9%, p = 0.017, OR: 4.13, 95% CI: 1.19-14.33 for TT genotype, 39.3% vs. 25.9%, p = 0.038 for T allele). If the application of TCF7L2 rs7903146 SNPs as a marker for PTDM is confirmed by further independent studies, replacing tacrolimus with other immunosuppressants could be warranted in patients at high risk of PTDM, as diagnosed by TCF7L2 genotyping.