Characterization of alendronic- and undecylenic acid coated magnetic nanoparticles for the targeted delivery of rosiglitazone to subcutaneous adipose tissue.

Obesity is a state of positive energy balance where excess white adipose tissue accumulates to the detriment of metabolic health. Improving adipocyte function with systemic administration of thiazolidinediones (TZDs) improves metabolic outcomes in obesity, however TZD use is limited clinically due to undesirable side effects. Here we evaluate magnetic nanoparticles (MNPs) as a tool to target rosiglitazone (Rosi) specifically to adipose tissue. Results show Rosi can be adsorbed to MNPs (Rosi-MNPs) with hydrophobic coatings for which we present binding and release kinetics. Rosi adsorbed to MNPs retained the ability to induce PPARγ target gene expression in cells. Biodistribution analysis of radiolabeled Rosi-MNPs revealed a fat-implanted magnet significantly enhanced localization of Rosi to the targeted adipose tissue when administered by subcutaneous injection to obese mice. We propose MNPs for targeted delivery of anti-diabetic agents to superficially located subcutaneous adipose tissue.

Distinct but phenotypically heterogeneous human cell populations produce rapid recovery of platelets and neutrophils after transplantation.

Delayed recovery of mature blood cells poses a serious, expensive, and often life-threatening problem for many stem cell transplantation recipients, particularly if heavily pretreated and serving as their own donor, or having a CB transplantation as the only therapeutic option. Importantly, the different cells required to ensure a rapid, as well as a permanent, hematopoietic recovery in these patients remain poorly defined. We now show that human CB and mobilized peripheral blood (mPB) collections contain cells that produce platelets and neutrophils within 3 weeks after being transplanted into sublethally irradiated NOD/scid-IL-2Rγc-null mice. The cells responsible for these 2 outputs are similarly distributed between the aldehyde dehydrogenase-positive and -negative subsets of lineage marker-negative CB and mPB cells, but their overall frequencies vary independently in individual samples. In addition, their total numbers can be seen to be much (> 30-fold) lower in a single "average" CB transplantation compared with a single "average" mPB transplantation (normalized for a similar weight of the recipient), consistent with the published differential performance in adult patients of these 2 transplantation products. Experimental testing confirmed the clinical relevance of the surrogate xenotransplantation assay for quantifying cells with rapid platelet regenerative activity, underscoring its potential for future applications.

The use of ultrasound to increase the uptake and cytotoxicity of dual taxane and P-glycoprotein inhibitor loaded, solid core nanoparticles in drug resistant cells.

The objective of this study was to use ultrasound in combination with nanoparticulate formulations of taxane drugs for an additive approach to overcome multidrug resistance (MDR). Polymeric nanoparticulate formulations containing both chemotherapeutic taxane drugs and a polymeric inhibitor (MePEG17-b-PCL5) of drug resistant proteins have been previously developed in an attempt to overcome MDR in cells. High frequency (>1 MHz) ultrasound has been shown to increase the uptake of cytotoxic drugs in MDR proliferating cells and has been suggested as a different way to overcome MDR, resensitize drug resistant cancer cells and allow for chemotherapeutic efficacy. MDCK-MDR cells were incubated with docetaxel (DTX) or paclitaxel (PTX) loaded, solid core, nanoparticles made from a 50:50 ratio of two diblock copolymers, MePEG114-b-PCL200 and MePEG17-b-PCL5 (PCL200/PCL5). The accumulation of drug in MDCK-MDR cells was measured using radiolabeled drug and the viability of cells was determined using an MTS cell proliferation assay. The effect of ultrasound (4 MHz, 32 W/cm2, 10 s, 25% duty cycle) on drug uptake and cell viability was studied. Using free DTX or PTX, MDCK-MDR cells were killed at sublethal doses of drug with the P-gp inhibitor (MePEG17-b-PCL5) present at a concentration of just 0.006% (m/v) and cell death began after just 3 h of incubation. Using sublethal incubation doses of PTX or DTX in PCL200/PCL5 nanoparticles for 90 min, followed by a second exposure to blank PCL200/PCL5 nanoparticles, cell viability dropped by approximately 60% at 24 h. Drug accumulation increased by 1.43-1.9 fold following five bursts of ultrasound applied at 90 min. Both, increased ultrasound exposure and increased concentrations of blank nanoparticles during the second incubation allowed for increased levels of cell death. The combined use of ultrasound with taxane and P-gp inhibitor loaded polymeric nanoparticles may allow for increased accumulation of drug and inhibitor which may then release both agents inside cells in a controlled manner to overcome drug resistance in MDR cells.

Survey of Therapeutic Drug Monitoring Practices in Pediatric Health Care Programs across Canada.

BACKGROUND: Therapeutic drug monitoring (TDM) is helpful in situations where a drug has a narrow therapeutic index, a drug dosage does not reliably predict serum concentration, or a serum drug concentration has surrogate value (i.e., is reflective of clinical outcomes). TDM is especially important for the pediatric population, where wide variability in pharmacokinetics and differences in body composition and drug disposition exist. Unfortunately, very little is known about pediatric TDM patterns and the factors that affect the ordering of serum drug measurements. OBJECTIVES: To describe TDM practice for pediatric patients in Canada, to report on the drugs that are monitored and how they are monitored, and to discern factors that influence pediatric TDM patterns. METHODS: An electronic survey was developed with online survey software and was disseminated to 42 pediatric health care centres in Canada over the period January to March 2016. RESULTS: Of the 42 sites invited to participate in the survey, 20 (48%) responded. All sites reported performing TDM for pediatric patients, and the median number of drugs monitored was 18.5 (range 9-28) per site. The sites differed in terms of TDM practice (e.g., indications for TDM, types of serum drug measurements). Pharmacogenetic testing currently does not play a major role in TDM. Reported barriers to TDM practice include perceived lack of clinical value for certain drugs, limited access to analytical testing, and delayed return of test results. CONCLUSIONS: TDM practice is widespread in Canada. To better utilize TDM for clinical practice, future efforts can be aimed toward increasing awareness of the clinical value of TDM and improving the timeliness of access to TDM results.

CONTEXTE: Le suivi thérapeutique pharmacologique est utile dans les cas où un médicament possède un indice thérapeutique étroit, si une posologie ne permet pas d'établir de façon fiable les concentrations sériques ou si les concentrations sériques d'un médicament ont une valeur de substitution (c'est-à-dire qu'elles reflètent les résultats cliniques). Le suivi thérapeutique pharmacologique est particulièrement important pour la population pédiatrique, où il existe une grande variabilité pharmacocinétique et des différences quant à la composition corporelle et au devenir des médicaments dans l'organisme. Malheureusement, on ne connaît que peu de choses à propos des habitudes de suivi thérapeutique pharmacologique de l'enfant et des facteurs qui influencent la prescription d'examens mesurant les concentrations sériques des médicaments. OBJECTIFS: Offrir un portrait des habitudes de suivi thérapeutique pharmacologique de la population pédiatrique au Canada, faire un compte rendu des médicaments qui nécessitent un suivi et la manière dont se déroule cette surveillance et déceler les facteurs qui influencent les habitudes de suivi thérapeutique pharmacologique de l'enfant. MÉTHODES: Un sondage électronique a été mis au point à l'aide d'un logiciel de sondage en ligne puis envoyé à 42 centres de soins pédiatriques au Canada de janvier à mars 2016. RÉSULTATS: Vingt (48 %) des 42 établissements interrogés ont répondu au sondage. Tous les établissements ont indiqué réaliser des suivis thérapeutiques pharmacologiques auprès de la population pédiatrique et le nombre médian de médicaments nécessitant une surveillance était de 18,5 (écart de 9 à 28) par établissement. Les établissements présentaient des différences en ce qui a trait aux habitudes de suivi thérapeutique pharmacologique (comme les indications pour les suivis thérapeutiques pharmacologiques et les types de mesures sériques de médicaments). À ce jour, les examens pharmacogénétiques ne jouent pas un rôle important dans le suivi thérapeutique pharmacologique. Selon les répondants, des éléments faisaient obstacle à la réalisation du suivi thérapeutique pharmacologique, notamment la croyance que certains médicaments n'ont pas de valeur clinique, l'accès limité à des tests diagnostiques et les retards dans l'obtention des résultats d'examen. CONCLUSIONS: La réalisation du suivi thérapeutique pharmacologique est répandue au Canada. Afin de l'exercer de façon plus optimale dans le cadre de la pratique clinique, le personnel de la santé doit être davantage sensibilisé à la valeur clinique du suivi thérapeutique pharmacologique et il est nécessaire d'améliorer la rapidité d'accès aux résultats de ce suivi.

Mixed molecular weight copolymer nanoparticles for the treatment of drug-resistant tumors: formulation development and cytotoxicity.

Nanoparticles composed of both high- and low-molecular-weight methoxy poly(ethylene glycol)-block-poly(caprolactone) (MePEG-b-PCL) diblock copolymers (termed "mixed molecular weight nanoparticles") were investigated for the encapsulation and delivery of the taxane drugs paclitaxel (PTX) and docetaxel (DTX). These nanoparticles were prepared using nanoprecipitation and emulsion methods. These 80 nm nanoparticles were prepared with high yields, efficiently solubilized PTX and DTX up to 500 and 1300 µg/mL, respectively, and demonstrated controlled release of these drugs over 14 days. The taxane-sensitive (MDCKII) and taxane-resistant [P-glycoprotein (P-gp) overexpressing] MDCKII-MDR cell lines were used to establish the cytotoxic profiles of these nanoparticles. Because of the coencapsulation of the previously demonstrated P-gp inhibitor, a low-molecular-weight MePEG-b-PCL copolymer (MePEG17 -b-PCL5 ), these drug-loaded mixed molecular weight nanoparticles dramatically reduced the viability of P-gp overexpressing MDCKII-MDR cells and restored sensitivity to taxane drugs in these cells.

Genotypic and functional diversity of phenotypically defined primitive hematopoietic cells in patients with chronic myeloid leukemia.

Much progress has been made in the management of chronic-phase chronic myeloid leukemia (CP-CML), but there is a continuing imperative to develop curative treatments, predict patient responses to specific modalities, and anticipate disease relapse or progression. These needs underlie continuing interest in methods to detect and quantify the relevant leukemic cells in clinical samples with improved reliability and specificity. We report the results of comparing three methods to enumerate primitive CP-CML cells in the same samples: genotyping CD34(+)38(-) cells directly by fluorescence in situ hybridization, and measuring BCR-ABL1 transcript-genotyped colony-forming cell outputs in either 5-week long-term cultures (LTCs) containing non-engineered mouse fibroblasts or in 6-week LTCs containing mouse fibroblasts engineered to produce human Steel factor, granulocyte colony-stimulating factor, and IL-3. The results demonstrate that the first two methods significantly overestimate the prevalence of primitive CP-CML cells by comparison to the third. In additional studies, we found that CML-CD34(+) cells can repopulate the marrow and spleen of serially transplanted adult NOD/SCID-IL-2Rγ chain-null mice for more than 1 year with an almost exclusive myeloid differentiation in primary and secondary recipients and without evidence of disease progression. These findings underscore the importance of long-term functional in vitro and in vivo endpoints to identify and characterize CP-CML stem cells.