Factors associated with generic health-related quality of life (HRQOL) in patients with chronic obstructive pulmonary disease (COPD): a cross-sectional study.

BACKGROUND: Health-related quality of life (HRQOL) is impaired in chronic obstructive pulmonary disease (COPD) patients, but determining factors for HRQOL are still not unequivocal. This study measures HRQOL among patients with COPD and aims to determine factors associated with HRQOL. METHODS: Data for cross-sectional analyses were obtained from the baseline of a cohort study. The study population includes adult COPD patients (disease duration ≥3 months), recruited from primary and secondary care settings in Germany, without acute psychiatric/neurologic disease (exception: affective/ anxiety disorders). HRQOL was assessed using the Short-Form 12 (SF-12) Health Survey Questionnaire, comprising a physical and mental component. Independent variables encompass socio-demographic, disease-specific, treatment-related and psychological factors. Multivariable linear regression analyses were conducted. RESULTS: In total, 206 COPD patients (60.7% male; mean age: 65.3 years) took part in the study. In multivariable analysis, the physical component score showed a significant negative association with the COPD Assessment Test (CAT) (P<0.001) and a higher total number of prescribed medications (P=0.001). A higher forced expiratory volume in 1 second (FEV1) value in percent predicted was significantly related to the physical component score in a positive manner (P=0.006). The mental component score was significantly associated with elevated patient-reported symptoms of anxiety (P=0.002) or depression (P<0.001), measured by the hospital anxiety and depression scale (HADS) in a negative way. Like for the physical component score (P<0.001), a worse CAT score was significantly associated with a lower mental component score (P=0.033). CONCLUSIONS: Focusing on patient reported outcomes and screening for depression and anxiety with potential successive treatment might be promising approaches to improve HRQOL in patients with COPD.

Specific, but not general beliefs about medicines are associated with medication adherence in patients with COPD, but not asthma: Cohort study in a population of people with chronic pulmonary disease.

BACKGROUND: Beliefs about medicines are regarded as influencing factors on medication adherence (Horne, 1997). Adherence levels in patients with chronic pulmonary diseases are low (Bourbeau and Bartlett, 2008; Sumino and Cabana, 2013). A better understanding of the predictive role of patients' beliefs about medicines for adherence might be a crucial step to improve medication adherence. OBJECTIVE: This prospective study investigated the association between beliefs about medicines and medication adherence in patients with asthma and COPD. METHODS: The Beliefs about Medicines Questionnaire (BMQ) and the Medication Adherence Rating Scale (MARS) were administered to 402 patients (49% asthma, 51% COPD, 50% female, mean age 56.7 years (SD = 15.9)) at baseline. Follow-ups were carried out after 3 (N = 255) and 12 months (N = 171). Multivariable logistic regression analyses were performed analysing the association between the BMQ subscales at baseline and adherence at each follow-up inquiry. Sociodemographic, psychosocial, and disease related factors were considered as potential confounders. RESULTS: One third of the patients showed adherent behavior (18% and 46% of people with asthma and COPD). In the COPD sample, the subscale Specific-necessity showed a significant positive association with adherence at the 3-months-follow-up (OR = 2.6, 95% CI 1.4-5.1) and the subscale Specific-concerns showed a significant inverse association with adherence at the 3-months-follow-up (OR = 0.6, 95% CI 0.3-0.95) and the 12-months-follow-up (OR = 0.4, 95% CI 0.2-0.8). No significant association was found for the asthmatic sample. CONCLUSIONS: Beliefs about medicines are important factors predicting future medication adherence in patients with COPD, but not asthma. Physicians should primarily focus on the specific beliefs of their patients in order to diminish medication non-adherence.

Differences in medication adherence are associated with beliefs about medicines in asthma and COPD.

Adherence to medication is crucial for achieving treatment control in chronic obstructive lung diseases. This study refers to the "necessity-concerns framework" and examines the associations between beliefs about medicines and self-reported medication adherence in people with chronic obstructive lung disease. 402 patients (196 with asthma, 206 with COPD) participated in the study and completed a questionnaire comprising the "Beliefs about Medicines-Questionnaire" (BMQ) and the "Medication Adherence Report Scale" (MARS). Multivariable logistic regression analyses with the BMQ-subscales as explanatory and the dichotomized MARS-score as dependent variable were computed for the asthma and the COPD sample, respectively, and adjusted for potentially confounding variables. 19% of asthma patients and 34% of COPD patients were completely adherent to their prescribed medication. While specific beliefs about the necessity of medicines were positively associated with medication adherence both in patients with asthma and with COPD, general beliefs about harm and overuse of medicines by doctors were negatively associated with medication adherence only among patients with asthma. The findings of this study suggest that patients' specific beliefs about the necessity of medicines represent an important modifiable target for improving patient-doctor consultations when prescribing medicines.

Factors associated with generic health-related quality of life in adult asthma patients in Germany: Cross-sectional study.

OBJECTIVES: Given a 9% lifetime prevalence of asthma in Germany and the impairment of health-related quality of life (HRQOL) that goes along with it, it is important to understand parameters affecting HRQOL in asthma patients. Objective of this study was therefore to determine factors associated with generic HRQOL in asthma patients. METHODS: Data for cross-sectional analyses were obtained from the baseline of an ongoing cohort study. INCLUSION CRITERIA: physician-diagnosed asthma; age ≥18 years; disease duration ≥3 months; no acute psychiatric/neurological disease; sufficient knowledge of German. HRQOL was assessed by the Short Form 12 Health Survey Questionnaire (SF-12), which comprises a physical (PCS-12) and a mental component (MCS-12). Information on a broad range of parameters potentially influencing HRQOL was collected by examining the patients' medical records and via a self-administered questionnaire. Those parameters were of socio-demographic, disease-specific, treatment-related or psychosocial nature. We conducted multivariable linear regression analyses to assess determinants of HRQOL. RESULTS: In total, 196 asthma patients participated in the study (mean age: 48 years (range: 18-90); 60.2% females). In multivariable analysis, PCS-12 was negatively associated with older age, being female, insufficient disease control, higher number of medications in tablet form and reporting symptoms of depression. MCS-12 was negatively associated with being female, living alone, insufficient disease control, and reporting symptoms of anxiety or depression. CONCLUSIONS: Focusing on disease control and screening for depression and anxiety may be promising approaches to improve HRQOL in adult asthma patients. If a patient shows alarming symptoms of anxiety and/or depression, the patient should then be referred for psychiatric treatment.

Inhibition of human intestinal α-glucosidases by calystegines.

Calystegines are polyhydroxylated nortropane alkaloids found in Convolvulaceae, Solanaceae, and other plant families. These plants produce common fruits and vegetables. The calystegine structures resemble sugars and suggest interaction with enzymes of carbohydrate metabolism. Maltase and sucrase are α-glucosidases contributing to human carbohydrate degradation in the small intestine. Inhibition of these enzymes by orally administered drugs is one option for treatment of diabetes mellitus type 2. In this study, inhibition of maltase and sucrase by calystegines A3 and B2 purified from potatoes was investigated. In silico docking studies confirmed binding of both calystegines to the active sites of the enzymes. Calystegine A3 showed low in vitro enzyme inhibition; calystegine B2 inhibited mainly sucrose activity. Both compounds were not transported by Caco-2 cells indicating low systemic availability. Vegetables rich in calystegine B2 should be further investigated as possible components of a diet preventing a steep increase in blood glucose after a carbohydrate-rich meal.

Colloidal structure and stability of DNA/polycations polyplexes investigated by small angle scattering.

Polyplexes of short DNA-fragments (300 b.p., 100 nm) with tailor-made amine-based polycations of different architectures (linear and hyperbranched) were investigated in buffer solution as a function of the mixing ratio with DNA. The resulting dispersed polyplexes were characterized using small-angle neutron and X-ray scattering (SANS, SAXS) as well as cryo-TEM with respect to their mesoscopic structure and their colloidal stability. The linear polyimines form rather compact structures that have a high tendency for precipitation. In contrast, the hyperbranched polycation with enzymatic-labile pentaethylenehexamine arms (PEHA) yields polyplexes colloidally stable for months. Here the polycation coating of DNA results in a homogeneous dispersion based on a fractal network with low structural organization at low polycation amount. With increasing polycation, bundles of tens of aligned DNA rods appear that are interconnected in a fractal network with a typical correlation distance on the order of 100 nm, the average length of the DNA used. With higher organization comes a decrease in stability. The 3D network built by these beams can still exhibit some stability as long as the material concentration is large enough, but the structure collapses upon dilution. SAXS shows that the complexation does not affect the local DNA structure. Interestingly, the structural findings on the DNA polyplexes apparently correlate with the transfection efficiency of corresponding siRNA complexes. In general, these finding not only show systematic trends for the colloid stability, but may allow for rational approaches to design effective transfection carriers.

Controlled release of DNA from photoresponsive hyperbranched polyglycerols with oligoamine shells.

Two photo-responsive core/shell nanoparticles based on hyperbranched polyglycerol (hPG) are synthesized for controlled release of DNA. The shell is composed either of bis-(3-aminopropyl)methylamine (AMPA) or pentaethylenehexamine (PEHA) derivatives and is attached to the hPG core with a photo-responsive o-nitrobenzyl linker. Ethidium bromide displacement assay, gel electrophoresis, DLS, and ζ-potential measurements are performed with these nanoparticles. Photo-responsive changes within the carrier scaffold are investigated by irradiating the polymer solution with 350 nm monochromatic light. Fully covered APMA-shelled carriers are found to complex the DNA at an N/P ratio of 10 with an average size ranging from 54 to 78 nm depending on the degree of functionalization of the core.

Dendritic polyglycerols with oligoamine shells show low toxicity and high siRNA transfection efficiency in vitro.

RNA interference provides great opportunities for treating diseases from genetic disorders, infection, and cancer. The successful application of small interference RNA (siRNA) in cells with high transfection efficiency and low cytotoxicity is, however, a major challenge in gene-mediated therapy. Several pH-responsive core shell architectures have been designed that contain a nitrogen shell motif and a polyglycerol core, which has been prepared by a two-step protocol involving the activation of primary and secondary hydroxyl groups by phenyl chloroformate and amine substitution. Each polymer was analyzed by particle size and ζ potential measurements, whereas the respective polyplex formation was determined by ethidium bromide displacement assay, atomic force microscopy (AFM), and surface charge analysis. The in vitro gene silencing properties of the different polymers were evaluated by using a human epithelial carcinoma cell (HeLaS3) line with different proteins (Lamin, CDC2, MAPK2). Polyplexes yielded similar knockdown efficiencies as HiPerFect controls, with comparably low cytotoxicity. Therefore, these efficient and highly biocompatible dendritic polyamines are promising candidates for siRNA delivery in vivo.

Synthesis of linear polyamines with different amine spacings and their ability to form dsDNA/siRNA complexes suitable for transfection.

In this paper we report on the synthesis of diversified linear polyamine architectures with different chain lengths and compositions and their interaction with phosphate groups of DNA/siRNA. The polyplex formation between model nucleotide (dsDNA) and these linear polyamines has been determined at different nitrogen to phosphorus (N/P) ratios using small-angle neutron scattering (SANS) and atomic force microscopy (AFM) techniques. AFM images showed that while linear poly(ethylene imine) (PEI)/DNA complex results in bigger spherical aggregates, poly(propylene imine)s forms torroid and cigar shaped structures upon complexation with DNA. The poly(butylene imine)s (LPBI)s form compact and soluble DNA complexes with a radii range of R(g) = 15-30 nm. Among the studied linear polyamines, the LPBIs did show the best transfection efficiency.

Uptake of codeine into intestinal epithelial (Caco-2) and brain endothelial (RBE4) cells.

Orally administered codeine has to permeate both the intestinal and the blood-brain barrier in order to act as analgesic and cough suppressant. In this study we characterized the uptake of codeine at intestinal epithelial (Caco-2) and brain endothelial (RBE4) cells. At both cell types, uptake of [(3)H]codeine was independent of an inwardly directed Na(+) gradient. Uptake was, however, strongly stimulated by an outwardly directed H(+) gradient and inhibited by the protonophore FCCP. [(3)H]Codeine uptake into Caco-2 cells was strongly temperature dependent. In the presence of excess amounts of unlabeled codeine, the uptake was inhibited by up to 87% (Caco-2) or 94% (RBE4), respectively. Synthetic opioids and some non-opioid organic cations like propranolol, pyrilamine and quinidine potently inhibited [(3)H]codeine uptake. Several prototype substrates of known transporters for amino acids, neurotransmitters and organic cations were ineffective. Our data are consistent with a hypothetic saturable, H(+)-dependent (antiport) mechanism not yet identified on a molecular level. The pH dependence of codeine uptake and its intracellular accumulation can partially also be explained by a model comprising diffusional membrane permeation of unionized species of codeine followed by codeine sequestration into acidic vesicles and distribution into cellular lipids.

In vivo delivery of small interfering RNA to tumors and their vasculature by novel dendritic nanocarriers.

New targets for RNA interference (RNAi)-based cancer therapy are constantly emerging from the increasing knowledge on key molecular pathways that are paramount for carcinogenesis. Nevertheless, in vivo delivery of small interfering RNA (siRNA) remains a crucial challenge for therapeutic success. siRNAs on their own are not taken up by most mammalian cells in a way that preserves their activity. Moreover, when applied in vivo, siRNA-based approaches are all limited by poor penetration into the target tissue and low silencing efficiency. To circumvent these limitations, we have developed novel polymerized polyglycerol-based dendrimer core shell structures to deliver siRNA to tumors in vivo. These cationic dendrimers can strongly improve the stability of the siRNA, its intracellular trafficking, its silencing efficacy, and its accumulation in the tumor environment owing to the enhanced permeability and retention effect. Here, we show that our dendritic nanocarriers exhibited low cytotoxicity and high efficacy in delivering active siRNA into cells. With use of human glioblastoma and murine mammary adenocarcinoma cell lines as model systems, these siRNA-dendrimer polyplexes silenced the luciferase gene, ectopically overexpressed in these cells. Importantly, significant gene silencing was accomplished in vivo within 24 h of treatment with our luciferase siRNA-nanocarrier polyplexes, as measured by noninvasive intravital bioluminescence imaging. Moreover, our siRNA-nanocarriers show very low levels of toxicity as no significant weight loss was observed after intravenous administration of the polyplexes. We show a proof of concept for siRNA delivery in vivo using a luciferase-based model. We predict that in vivo silencing of important cell growth and angiogenesis regulator genes in a selective manner will justify this approach as a successful anticancer therapy.

Transport of phenylethylamine at intestinal epithelial (Caco-2) cells: mechanism and substrate specificity.

This study was performed to characterize the intestinal transport of beta-phenylethylamine (PEA). Uptake of [(14)C]PEA into Caco-2 cells was Na(+)-independent but strongly stimulated by an outside directed H(+) gradient. At extracellular pH 7.5, the concentration-dependent uptake of PEA was saturable with kinetic parameters of 2.6mM (K(t)) and 96.2nmol/min per mg of protein (V(max)). Several biogenic amines such as harmaline and N-methylphenylethylamine as well as cationic drugs such as phenelzine, tranylcypromine, d,l-amphetamine, methadone, chlorphenamine, diphenhydramine and promethazine strongly inhibited the [(14)C]PEA uptake with K(i) values around 1mM. Tetraethylammonium, N-methyl-4-phenylpyridinium and choline had no effect. We also studied the bidirectional transepithelial transport of [(14)C]PEA at cell monolayers cultured on permeable filters. Net transepithelial flux of [(14)C]PEA from apical-to-basolateral side exceeded basolateral-to-apical flux 5-fold. We conclude that PEA is transported into Caco-2 cells by a highly active, saturable, H(+)-dependent (antiport) process. The transport characteristics do not correspond to those of the known carriers for organic cations of the SLC22, SLC44, SLC47 and other families.

Hyperbranched polyamines for transfection.

The successful application of gene therapy through DNA transfection into the cell is still a great challenge in ongoing research. Hyperbranched polyamines are highly branched macromolecules, and have gained significant attention in the last two decades, due to their relative ease of preparation, their shape, and their multi-functionality. This review deals with the syntheses of various hyperbranched polyamines that are prepared through a one-step polymerization process. Furthermore, we present the current status of polyamines as gene carriers and describe their versatility, and their properties such as structure-property dependency, gene transfection efficiency, and cytotoxicity profiles of hyperbranched polyamines.

High-affinity interaction of sartans with H+/peptide transporters.

Sartans are very effective drugs for treatment of hypertension, heart failure, and other cardiovascular disorders. They antagonize the effects of angiotensin II at the AT(1) receptor and display p.o. bioavailability rates of 13 to 80%. Because some sartans sterically resemble dipeptide derivatives, we investigated whether they are transported by peptide transporters. We first assessed the effects of sartans on [(14)C]glycylsarcosine uptake into Caco-2 cells expressing H(+)/peptide transporter (PEPT) 1 and into SKPT cells expressing PEPT2. Losartan, irbesartan, valsartan, and eprosartan inhibited [glycine-1-(14)C]glycylsarcosine ([(14)C]Gly-Sar) uptake into Caco-2 cells in a competitive manner with K(i) values of 24, 230, 390, and >1000 microM. Losartan and valsartan also strongly inhibited the total transepithelial flux of [(14)C]Gly-Sar across Caco-2 cell monolayers. In SKPT cells, [(14)C]Gly-Sar uptake was inhibited with K(i) values of 2.2 microM (losartan), 65 microM (irbesartan), 260 microM (valsartan), and 490 microM (eprosartan). We determined by the two-electrode voltage-clamp technique whether the compounds elicited transport currents by PEPT1 or PEPT2 when expressed in Xenopus laevis oocytes. No currents were observed for any of the sartans, but the compounds strongly and reversibly inhibited peptide-induced currents. Uptake of valsartan, losartan, and cefadroxil was quantified in HeLa cells after heterologous expression of human PEPT1 (hPEPT1). In contrast to cefadroxil, no PEPT1-specific uptake of valsartan and losartan was found. We conclude that the sartans tested in this study display high-affinity interaction with PEPTs but are not transported themselves. However, they strongly inhibit hPEPT1-mediated uptake of dipeptides and cefadroxil.

Transport of angiotensin-converting enzyme inhibitors by H+/peptide transporters revisited.

Angiotensin-converting enzyme (ACE) inhibitors are often regarded as substrates for the H+/peptide transporters (PEPT)1 and PEPT2. Even though the conclusions drawn from published data are quite inconsistent, in most review articles PEPT1 is claimed to mediate the intestinal absorption of ACE inhibitors and thus to determine their oral availability. We systematically investigated the interaction of a series of ACE inhibitors with PEPT1 and PEPT2. First, we studied the effect of 14 ACE inhibitors including new drugs on the uptake of the dipeptide [14C]glycylsarcosine into human intestinal Caco-2 cells constitutively expressing PEPT1 and rat renal SKPT cells expressing PEPT2. In a second approach, the interaction of ACE inhibitors with heterologously expressed human PEPT1 and PEPT2 was determined. In both assay systems, zofenopril and fosinopril were found to have very high affinity for binding to peptide transporters. Medium to low affinity for transporter interaction was found for benazepril, quinapril, trandolapril, spirapril, cilazapril, ramipril, moexipril, quinaprilat, and perindopril. For enalapril, lisinopril, and captopril, very weak affinity or lack of interaction was found. Transport currents of PEPT1 and PEPT2 expressed in Xenopus laevis oocytes were recorded by the two-electrode voltage-clamp technique. Statistically significant, but very low currents were only observed for lisinopril, enalapril, quinapril, and benazepril at PEPT1 and for spirapril at PEPT2. For the other ACE inhibitors, electrogenic transport activity was extremely low or not measurable at all. The present results suggest that peptide transporters do not control intestinal absorption and renal reabsorption of ACE inhibitors.

Transport of valproate at intestinal epithelial (Caco-2) and brain endothelial (RBE4) cells: mechanism and substrate specificity.

To reach its target cells, the antiepileptic drug valproate has to cross both the intestinal epithelial barrier and the blood-brain barrier in intact form as well as in sufficient amounts. This study was performed to characterize the epithelial transport of valproate at intestinal (Caco-2) and at blood-brain barrier (RBE4) cells. At both cell types, uptake of [(3)H]valproate was independent of inwardly directed Na(+), Ca(2+), Mg(2+), K(+) or Cl(-) gradients. Uptake was, however, strongly stimulated by an inwardly directed H(+) gradient. The cells accumulated valproate against a concentration gradient and the uptake rate of valproate was saturable with K(t) values of 0.6 and 0.8mM. At Caco-2 cell monolayers, the total apical-to-basolateral flux of [(3)H]valproate exceeded the basolateral-to-apical flux 14-fold. Various monocarboxylic acids like salicylate, benzoate, acetate, propionate, butyrate, hexanoate, diclofenac and ibuprofen inhibited [(3)H]valproate uptake at both cell types. Lactate and pyruvate inhibited valproate uptake at RBE4 cells but not at Caco-2 cells. We conclude that valproate is accumulated in intestinal cells against a concentration gradient by the activity of a specific H(+)-dependent DIDS-insensitive transport system for monocarboxylates not identical with monocarboxylate transporter 1 (MCT1). The passage of valproate across the blood-brain barrier is very likely mediated by MCT1.

Clonidine accumulation in human neuronal cells.

After transport across several epithelial barriers including the blood-brain barrier, clonidine interacts with alpha(2)-adrenergic receptors and imidazoline binding sites in the brain. We hypothesized that neuronal cells take up clonidine thereby removing the drug from the extracellular fluid compartment. Uptake of [(3)H]clonidine into SH-SY5Y neuroblastoma cells was linear for up to 1 min, unaffected by inside directed Na(+) or Cl(-) gradients but strongly inhibited by an outside pH of 6.0. The cells accumulated [(3)H]clonidine 50-70-fold uphill against a concentration gradient. Unlabeled clonidine, guanabenz, imipramine, diphenhydramine, maprotiline, quinine and the endogenous monoamine phenylethylamine (2 mM) strongly inhibited the [(3)H]clonidine uptake by 60-95%. Tetraethylammonium, choline and N-methyl-4-phenylpyridinium had no effect. The accumulation at pH 7.5 was saturable with an apparent Michaelis-Menten constant (K(t)) of 0.7 mM. We conclude that SH-SY5Y cells not only bind clonidine to extracellular receptors but also take up the drug rapidly by a specific and concentrative mechanism.

Substrate specificity and mechanism of the intestinal clonidine uptake by Caco-2 cells.

PURPOSE: This study was performed to characterize the substrate specificity and mechanism of the intestinal clonidine transport. METHODS: Uptake of [3H]clonidine into Caco-2 cells was investigated. Interaction with drugs was studied in competition assays. RESULTS: Uptake of [3H]clonidine was linear for up to 2 min, Na+-independent, and insensitive to changes in membrane potential, but strongly H+-dependent. The uptake rate of clonidine was saturable with kinetic parameters of 0.5+/-0.1 mM (Kt) and 16.6+/-1.8 nmol/2 min per mg of protein (Vmax) at an outside pH of 7.5. Many drugs such as clonidine, guanabenz, methamphetamine, imipramine, clomipramine, nortriptyline, quinine, xylazine, ephedrine, and diphenhydramine strongly inhibited the [3H]clonidine uptake with Ki values between 0.15 and 1 mM. CONCLUSIONS: Clonidine is transported by a carrier-mediated process. Substrate specificity and mechanism are very similar to the transport described in blood-brain barrier endothelial cells. The transport characteristics do not correspond to carriers for organic cations of the SLC22 family or the choline transporters CHT1 and CLT1. The system might be identical to the H+/tertiary amine antiporter. It interacts with a large number of both hydrophilic and lipophilic cationic drugs, and also, interestingly, with opiates.