RESUMO
BACKGROUND: This study aimed to develop, validate and compare the performance of models predicting post-treatment outcomes for depressed adults based on pre-treatment data. METHODS: Individual patient data from all six eligible randomised controlled trials were used to develop (k = 3, n = 1722) and test (k = 3, n = 918) nine models. Predictors included depressive and anxiety symptoms, social support, life events and alcohol use. Weighted sum scores were developed using coefficient weights derived from network centrality statistics (models 1-3) and factor loadings from a confirmatory factor analysis (model 4). Unweighted sum score models were tested using elastic net regularised (ENR) and ordinary least squares (OLS) regression (models 5 and 6). Individual items were then included in ENR and OLS (models 7 and 8). All models were compared to one another and to a null model (mean post-baseline Beck Depression Inventory Second Edition (BDI-II) score in the training data: model 9). Primary outcome: BDI-II scores at 3-4 months. RESULTS: Models 1-7 all outperformed the null model and model 8. Model performance was very similar across models 1-6, meaning that differential weights applied to the baseline sum scores had little impact. CONCLUSIONS: Any of the modelling techniques (models 1-7) could be used to inform prognostic predictions for depressed adults with differences in the proportions of patients reaching remission based on the predicted severity of depressive symptoms post-treatment. However, the majority of variance in prognosis remained unexplained. It may be necessary to include a broader range of biopsychosocial variables to better adjudicate between competing models, and to derive models with greater clinical utility for treatment-seeking adults with depression.
Assuntos
Ansiedade , Depressão , Humanos , Adulto , Depressão/psicologia , Prognóstico , Resultado do Tratamento , Escalas de Graduação PsiquiátricaRESUMO
BACKGROUND: Depression is commonly perceived as a single underlying disease with a number of potential treatment options. However, patients with major depression differ dramatically in their symptom presentation and comorbidities, e.g. with anxiety disorders. There are also large variations in treatment outcomes and associations of some anxiety comorbidities with poorer prognoses, but limited understanding as to why, and little information to inform the clinical management of depression. There is a need to improve our understanding of depression, incorporating anxiety comorbidity, and consider the association of a wide range of symptoms with treatment outcomes. METHOD: Individual patient data from six RCTs of depressed patients (total n = 2858) were used to estimate the differential impact symptoms have on outcomes at three post intervention time points using individual items and sum scores. Symptom networks (graphical Gaussian model) were estimated to explore the functional relations among symptoms of depression and anxiety and compare networks for treatment remitters and those with persistent symptoms to identify potential prognostic indicators. RESULTS: Item-level prediction performed similarly to sum scores when predicting outcomes at 3 to 4 months and 6 to 8 months, but outperformed sum scores for 9 to 12 months. Pessimism emerged as the most important predictive symptom (relative to all other symptoms), across these time points. In the network structure at study entry, symptoms clustered into physical symptoms, cognitive symptoms, and anxiety symptoms. Sadness, pessimism, and indecision acted as bridges between communities, with sadness and failure/worthlessness being the most central (i.e. interconnected) symptoms. Connectivity of networks at study entry did not differ for future remitters vs. those with persistent symptoms. CONCLUSION: The relative importance of specific symptoms in association with outcomes and the interactions within the network highlight the value of transdiagnostic assessment and formulation of symptoms to both treatment and prognosis. We discuss the potential for complementary statistical approaches to improve our understanding of psychopathology.
Assuntos
Depressão , Transtorno Depressivo Maior , Adulto , Ansiedade/diagnóstico , Ansiedade/epidemiologia , Transtornos de Ansiedade , Depressão/diagnóstico , Depressão/epidemiologia , Humanos , PrognósticoRESUMO
In transplantation, immunosuppression has been directed at controlling acute responses, but treatment of chronic rejection has been ineffective. It is possible that factors that have previously been unaccounted for, such as exposure to inhaled pollution, ultraviolet light, or loss of the normal equilibrium between the gut immune system and the outside environment may be responsible for shifting immune responses to an effector/inflammatory phenotype, which leads to loss of self-tolerance and graft acceptance, and a shift towards autoimmunity and chronic rejection. Cells of the immune system are in a constant balance of effector response, regulation, and quiescence. Endogenous and exogenous signals can shift this balance through the aryl hydrocarbon receptor, which serves as a thermostat to modulate the response one way or the other, both at mucosal surfaces of interface organs to the outside environment, and in the internal milieu. Better understanding of this balance will identify a target for maintenance of self-tolerance and continued graft acceptance in patients who have achieved a "steady state" after transplantation.
Assuntos
Exposição Ambiental/efeitos adversos , Rejeição de Enxerto/etiologia , Tolerância Imunológica/imunologia , Transplante de Órgãos/efeitos adversos , Animais , HumanosRESUMO
Prostate cancer is the most common cancer in men of the western world. To date, no effective treatment exists for metastatic prostate cancer and consequently, there is an urgent need to develop new and improved therapeutics. In recent years, the therapeutic potential of RNA interference (RNAi) has been extensively explored in a wide range of diseases including prostate cancer using numerous gene delivery vectors. The aims of this study were to investigate the ability of a non-viral modified cyclodextrin (CD) vector to deliver siRNA to the highly metastatic PC-3 prostate cancer cell line, to quantify the resulting knockdown of the two target genes (RelA and SRF) and to study the effects of the silencing on metastasis. Data from a Matrigel in vitro invasion assay indicated that the silencing of the target genes achieved by the CD vector resulted in significant reductions (P=0.0001) in the metastatic potential of these cells. As the silencing of these target genes was shown not to have a negative impact on cell viability, we hypothesise that the mechanism of invasion inhibition is due, in part, to the significant reduction observed (P⩽0.0001) in the level of pro-inflammatory cytokine, MMP9, which is known to be implicated in the metastasis of prostate cancer.
Assuntos
Ciclodextrinas , Vetores Genéticos , NF-kappa B/genética , Neoplasias da Próstata/terapia , RNA Interferente Pequeno/administração & dosagem , Fator de Resposta Sérica/genética , Fator de Transcrição RelA/genética , Linhagem Celular Tumoral , Humanos , Masculino , Invasividade Neoplásica/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Interferência de RNA , RNA Interferente Pequeno/genéticaRESUMO
Approximately half of generalised anxiety disorder (GAD) patients do not recover from first-line treatments, and no validated prediction models exist to inform individuals or clinicians of potential treatment benefits. This study aimed to develop and validate an accurate and explainable prediction model of post-treatment GAD symptom severity. Data from adults receiving treatment for GAD in eight Improving Access to Psychological Therapies (IAPT) services (n=15,859) were separated into training, validation and holdout datasets. Thirteen machine learning algorithms were compared using 10-fold cross-validation, against two simple clinically relevant comparison models. The best-performing model was tested on the holdout dataset and model-specific explainability measures identified the most important predictors. A Bayesian Additive Regression Trees model out-performed all comparison models (MSE=16.54 [95 % CI=15.58; 17.51]; MAE=3.19; R²=0.33, including a single predictor linear regression model: MSE=20.70 [95 % CI=19.58; 21.82]; MAE=3.94; R²=0.14). The five most important predictors were: PHQ-9 anhedonia, GAD-7 annoyance/irritability, restlessness and fear items, then the referral-assessment waiting time. The best-performing model accurately predicted post-treatment GAD symptom severity using only pre-treatment data, outperforming comparison models that approximated clinical judgement and remaining within the GAD-7 error of measurement and minimal clinically important differences. This model could inform treatment decision-making and provide desired information to clinicians and patients receiving treatment for GAD.
Assuntos
Transtornos de Ansiedade , Aprendizado de Máquina , Índice de Gravidade de Doença , Humanos , Transtornos de Ansiedade/terapia , Adulto , Masculino , Feminino , Pessoa de Meia-Idade , Psicoterapia/métodos , Teorema de Bayes , Adulto JovemRESUMO
BACKGROUND: Sleep disturbance is a common symptom of depression. There is conflicting evidence whether improvements in sleep might impact depressive symptoms, or whether treating the core depressive symptoms might improve sleep disturbance. This study explored the bi-directional impact of sleep and depressive symptom change among individuals receiving psychological treatment. METHODS: Session-by-session change in sleep disturbance and depressive symptom severity scores were explored in patients receiving psychological therapy for depression from Improving Access to Psychological Therapies services in England. Bi-directional change in sleep disturbance and depressive symptoms was modelled using random-intercept cross-lagged panel models with items from the PHQ-9. RESULTS: The sample included 17,732 adults that had received three or more treatment sessions. Both depressive symptoms and sleep disturbance scores decreased. Between initial timepoints, higher sleep disturbance was associated with lower depression scores, but after this point positive cross-lagged effects were observed for both the impact of sleep disturbance on later depressive symptoms, and depressive symptoms on later sleep disturbance scores. The magnitude of effects suggested depressive symptoms may have more impact on sleep than the reverse, and this effect was larger in sensitivity analyses. CONCLUSIONS: Findings provide evidence that psychological therapy for depression results in improvements in core depressive symptoms and sleep disturbance. There was some evidence that depressive symptoms may have more impact on sleep disturbance scores at the next therapy session, than sleep disturbance does on later depressive symptoms. Targeting the core symptoms of depression initially may optimise outcomes, but further research is needed to elucidate these relationships.
Assuntos
Depressão , Transtornos do Sono-Vigília , Adulto , Humanos , Depressão/terapia , Depressão/complicações , Transtornos do Sono-Vigília/psicologia , Inglaterra , SonoRESUMO
Psychotherapy is an effective treatment for many common mental health problems, but the mechanisms of action and processes of change are unclear, perhaps driven by the focus on a single diagnosis which does not reflect the heterogeneous symptom experiences of many patients. The objective of this study was to better understand therapeutic change, by illustrating how symptoms evolve and interact during psychotherapy. Data from 113,608 patients from psychological therapy services who completed depression and anxiety symptom measures across three to six therapy sessions were analysed. A panel graphical vector-autoregression model was estimated in a model development sample (N = 68,165) and generalizability was tested in a confirmatory model, fitted to a separate (hold-out) sample of patients (N = 45,443). The model displayed an excellent fit and replicated in the confirmatory holdout sample. First, we found that nearly all symptoms were statistically related to each other (i.e. dense connectivity), indicating that no one symptom or association drives change. Second, the structure of symptom interrelations which emerged did not change across sessions. These findings provide a dynamic view of the process of symptom change during psychotherapy and give rise to several causal hypotheses relating to structure, mechanism, and process.
Assuntos
Ansiedade , Psicoterapia , Ansiedade/psicologia , Ansiedade/terapia , Transtornos de Ansiedade/psicologia , Humanos , Resultado do TratamentoRESUMO
AIMS: To determine whether age, gender and marital status are associated with prognosis for adults with depression who sought treatment in primary care. METHODS: Medline, Embase, PsycINFO and Cochrane Central were searched from inception to 1st December 2020 for randomised controlled trials (RCTs) of adults seeking treatment for depression from their general practitioners, that used the Revised Clinical Interview Schedule so that there was uniformity in the measurement of clinical prognostic factors, and that reported on age, gender and marital status. Individual participant data were gathered from all nine eligible RCTs (N = 4864). Two-stage random-effects meta-analyses were conducted to ascertain the independent association between: (i) age, (ii) gender and (iii) marital status, and depressive symptoms at 3-4, 6-8,
Assuntos
Antidepressivos , Depressão , Adulto , Antidepressivos/uso terapêutico , Ansiedade , Depressão/diagnóstico , Depressão/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estado Civil , PrognósticoRESUMO
Previous research has reported that patients require specific information relating to radiotherapy; however, these studies fail to describe patients' specific information needs over time. The aims of this study were to determine the specific information needs of breast cancer patients who are receiving radiotherapy and identify when patients prefer to receive specific information. Semi-structured interviews were conducted with 34 early breast cancer patients and 14 health professionals. Seventeen patients were interviewed after treatment completion, and 17 patients were interviewed on at least two occasions during their radiotherapy. Grounded theory and the constant comparative method were used to analyse the data. Three main categories emerged from the data: 'repertoire of information', 'amount of information relating specifically to radiotherapy' and'tailoring information to match patients' radiotherapy journeys'. Patients' information needs were identified, and key messages and strategies to inform patients were described. This paper identifies breast cancer patient's specific information needs during radiotherapy and shows that patients' information needs are highest during their first appointment with their radiation oncologist and at the time of their planning appointment. The findings presented will enable health professionals to develop and refine their approaches to patient education in radiotherapy.
Assuntos
Neoplasias da Mama/radioterapia , Comunicação , Educação de Pacientes como Assunto/organização & administração , Preferência do Paciente/psicologia , Adolescente , Adulto , Idoso , Neoplasias da Mama/psicologia , Feminino , Pessoal de Saúde , Necessidades e Demandas de Serviços de Saúde , Humanos , Entrevistas como Assunto , Pessoa de Meia-Idade , Educação de Pacientes como Assunto/normas , Adulto JovemRESUMO
The percentage of new chemical entities synthesised with low aqueous solubility and high therapeutic efficacy is growing, this presents major challenges for the drug delivery scientists. The role of physicochemical properties in identification of suitable drug candidates for oral lipid-based delivery systems is discussed. A knowledge of the interplay of physicochemical and biopharmaceutical drug properties with the physiological environment of the gastro-intestinal tract (GIT), as a prerequisite to successful formulation design, is reviewed. The importance of excipient selection with an emphasis on bioactive excipients is stressed. The need for more examples of in vitro-in vivo correlations as a means of maximizing the development potential and commercial future for lipid-based formulations, and, promoting confidence within the industry for these delivery systems is highlighted.
Assuntos
Desenho de Fármacos , Lipídeos/química , Preparações Farmacêuticas/química , Administração Oral , Animais , Química Farmacêutica/métodos , Portadores de Fármacos/química , Trato Gastrointestinal/metabolismo , Humanos , Preparações Farmacêuticas/administração & dosagem , Solubilidade , Água/químicaRESUMO
Background Confidential reporting systems play a key role in capturing information about adverse surgical events. However, the value of these systems is limited if the reports that are generated are not subjected to systematic analysis. The aim of this study was to provide the first systematic analysis of data from a novel surgical confidential reporting system to delineate contributory factors in surgical incidents and document lessons that can be learned. Methods One-hundred and forty-five patient safety incidents submitted to the UK Confidential Reporting System for Surgery over a 10-year period were analysed using an adapted version of the empirically-grounded Yorkshire Contributory Factors Framework. Results The most common factors identified as contributing to reported surgical incidents were cognitive limitations (30.09%), communication failures (16.11%) and a lack of adherence to established policies and procedures (8.81%). The analysis also revealed that adverse events were only rarely related to an isolated, single factor (20.71%) - with the majority of cases involving multiple contributory factors (79.29% of all cases had more than one contributory factor). Examination of active failures - those closest in time and space to the adverse event - pointed to frequent coupling with latent, systems-related contributory factors. Conclusions Specific patterns of errors often underlie surgical adverse events and may therefore be amenable to targeted intervention, including particular forms of training. The findings in this paper confirm the view that surgical errors tend to be multi-factorial in nature, which also necessitates a multi-disciplinary and system-wide approach to bringing about improvements.
Assuntos
Confidencialidade , Erros Médicos/estatística & dados numéricos , Segurança do Paciente , Gestão de Riscos/métodos , Humanos , Fatores de Risco , Reino UnidoRESUMO
A clinical neurophysiologist must recognize patterns in EEG signals to evaluate the health of a patient's brain activity. Rare or unusual patterns may take time to correctly identify. The ability to automatically assist this recall would be beneficial in ensuring that appropriate measures could be taken in a timely fashion. Audio fingerprinting is a method used to identify songs using only a snippet of the song. Fingerprints are extracted from a sub-section of the song and matched against a database of previously computed fingerprints. In this paper, a fingerprint quantization technique is implemented on neonatal EEG data to attempt to identify sections of EEG data when only seeing a sub-section of the data. The impact of signal distortions is investigated and results from a database of one hour recordings from 40 newborns are presented.
Assuntos
Eletroencefalografia/métodos , Processamento de Sinais Assistido por Computador , Acústica , Algoritmos , Bases de Dados Factuais , Humanos , Lactente , Recém-Nascido , Razão Sinal-RuídoRESUMO
BACKGROUND: The Mycobacterium abscessus complex are the rapidly growing mycobacteria (RGM) most commonly causing lung disease, especially in cystic fibrosis (CF) patients. Ireland has the world's highest CF incidence. The molecular epidemiology of M. abscessus complex in Ireland is unreported. METHODS: We performed rpoB gene sequencing and multi-locus sequence typing (MLST) on M. abscessus complex strains isolated from thirty-six patients in 2006-2012 (eighteen known CF patients). RESULTS: Twenty-eight strains (78%) were M. abscessus subsp. abscessus, eight M. abscessus subsp. massiliense, none were M. abscessus subsp. bolletii. Sequence type 1 (ST1) and ST26 (M. abscessus subsp. abscessus) were commonest. Seven M. abscessus subsp. abscessus STs (25%) were novel (two with novel alleles). Seven M. abscessus subsp. massiliense STs were previously reported (88%), including two ST23, the globally successful clone. In 2012, of 552 CF patients screened, eleven were infected with M. abscessus complex strains (2%). CONCLUSIONS: The most prevalent M. abscessus subsp. abscessus and M. abscessus subsp. massiliense strains in Ireland belong to widely-distributed STs, but there is evidence of high M. abscessus subsp. abscessus diversity.
Assuntos
Fibrose Cística/complicações , DNA Bacteriano/genética , Epidemiologia Molecular/métodos , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Micobactérias não Tuberculosas/genética , Técnicas de Tipagem Bacteriana , Fibrose Cística/epidemiologia , Humanos , Incidência , Irlanda/epidemiologia , Infecções por Mycobacterium não Tuberculosas/complicações , Infecções por Mycobacterium não Tuberculosas/microbiologia , Micobactérias não Tuberculosas/isolamento & purificação , Estudos RetrospectivosRESUMO
Recent work has highlighted the importance of protein post-translational modifications such as phosphorylation (enzymatic) and nitrosylation (nonenzymatic) in the early stages of apoptosis. In this study, we have investigated the levels of protein carbonylation, a nonenzymatic protein modification that occurs in conditions of cellular oxidative stress, during etopside-induced apoptosis of HL60 cells. Within 1 h of VP16 treatment, a number of proteins underwent carbonylation due to oxidative stress. This was inhibited by the antioxidant N-acetyl-L-cysteine. Among the proteins found to be carbonylated were glycolytic enzymes. Subsequently, we found that the rate of glycolysis was significantly reduced, probably due to a carbonylation mediated reduction in enzymatic activity of glycolytic enzymes. Our work demonstrates that protein carbonylation can be rapidly induced through cytotoxic drug treatment and may specifically inhibit the glycolytic pathway. Given the importance of glycolysis as a source of cellular ATP, this has severe implications for cell function.
Assuntos
Apoptose/efeitos dos fármacos , Estresse Oxidativo , Proteínas/metabolismo , Acetilcisteína/farmacologia , Western Blotting , Carbono/metabolismo , Eletroforese em Gel Bidimensional , Etoposídeo/toxicidade , Citometria de Fluxo , Sequestradores de Radicais Livres/farmacologia , Glicólise , Células HL-60 , Humanos , Hidrazinas/metabolismo , Peróxido de Hidrogênio/farmacologia , Oxirredução , Testes de Precipitina , Espécies Reativas de Oxigênio/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Fatores de TempoRESUMO
Development of the nervous system is a complex process, involving coordinated regulation of diverse cellular processes including proliferation, differentiation and synaptogenesis. Disturbances to brain development such as pre- and perinatal hypoxia have been linked to behavioural and late onset of neurological disorders. This study examines the effect of hypoxia on neurite outgrowth in PC12 cells. Hypoxia not only caused a rapid induction of neurite outgrowth, but also synergistically enhanced nerve growth factor (NGF)-induced neurite outgrowth up to 24 h. Transactivation of TrkA receptors was ruled out since the TrkA inhibitor K252a did not block hypoxia-induced neurite outgrowth. Adenosine deaminase prevented hypoxia-induced neurite outgrowth indicating that the effect is mediated by adenosine. Use of the specific adenosine A2A receptor agonist CGS21680 and antagonist 8-3(chlorostyryl)caffeine demonstrated that activation of this receptor is critical for hypoxia-induced neurite outgrowth. Hypoxia-induced neurite outgrowth was blocked by the adenylate cyclase inhibitor, MDL-12,330A, indicating a role for activation of this enzyme in the pathway. Hypoxia was further shown to cause a decrease in growth-associated protein (GAP)-43 levels and a lack of induction of betaIII tubulin, in contrast to NGF treatment which resulted in increased cellular levels of both of these proteins. These findings suggest that hypoxia induces neurite outgrowth in PC12 cells via a pathway distinct from that activated by NGF. Thus, exposure to hypoxia at critical stages of development may contribute to aberrant neurite outgrowth and could be a factor in the pathogenesis of certain delayed developmental neurological disorders.
Assuntos
Adenosina/análogos & derivados , Neuritos/fisiologia , Receptor A2A de Adenosina/fisiologia , Adenosina/farmacologia , Animais , Hipóxia Celular/efeitos dos fármacos , Hipóxia Celular/fisiologia , Relação Dose-Resposta a Droga , Fator de Crescimento Neural/farmacologia , Neuritos/efeitos dos fármacos , Células PC12 , Fenetilaminas/farmacologia , RatosRESUMO
Recent developments in "Big Data" have brought significant gains in the ability to process large amounts of data on commodity server hardware. Stream computing is a relatively new paradigm in this area, addressing the need to process data in real time with very low latency. While this approach has been developed for dealing with large scale data from the world of business, security and finance, there is a natural overlap with clinical needs for physiological signal processing. In this work we present a case study of streams processing applied to a typical physiological signal processing problem: QRS detection from ECG data.
Assuntos
Eletrocardiografia/classificação , Computação em Informática Médica , Processamento de Sinais Assistido por Computador , HumanosRESUMO
An outbreak of linezolid-resistant vancomycin-resistant Enterococcus faecium (LRVREfm) occurred in the hepatology ward of a tertiary referral hospital in Ireland between February and September 2014. LRVREfm was isolated from 15 patients; pulsed-field gel electrophoresis confirmed spread of a single clone. This is the first report of an outbreak of linezolid-resistant vancomycin-resistant enterococcus in Ireland.
Assuntos
Antibacterianos/farmacologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças , Enterococcus faecium/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/epidemiologia , Linezolida/farmacologia , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana , Eletroforese em Gel de Campo Pulsado , Enterococcus faecium/classificação , Enterococcus faecium/genética , Enterococcus faecium/isolamento & purificação , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Irlanda/epidemiologia , Epidemiologia Molecular , Tipagem Molecular , Centros de Atenção Terciária , Enterococos Resistentes à Vancomicina/isolamento & purificaçãoRESUMO
This case report demonstrates the successful localization of metastatic medullary thyroid carcinoma with 99mTc-labeled methoxyisobutylnitrile (MIBI). Disease recurrence was initially localized using 201Tl and by immunoscintigraphy with 111In-labeled anti-carcinoembryonic antigen (anti-CEA) antibody fragments. Scintigraphy with 99mTc-MIBI yielded higher target-to-background ratios than 201Tl or 111In-anti-CEA. Technetium-99m-MIBI may be a useful agent in the localization of recurrent medullary thyroid carcinoma.
Assuntos
Carcinoma/secundário , Neoplasias de Cabeça e Pescoço/secundário , Nitrilas , Compostos de Organotecnécio , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Carcinoma/diagnóstico por imagem , Feminino , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Pessoa de Meia-Idade , Cintilografia , Tecnécio Tc 99m Sestamibi , Neoplasias da Glândula Tireoide/patologiaRESUMO
A mucus secreting CaCo-2-Ht29GlucH cell co-culture model was characterised and used to examine the influence of mucus as a barrier to the transport of hydrophilic and lipophilic compounds in the absence and presence of sodium taurocholate micellar (NaTC) systems. TEER measurements and permeability studies using the hydrophilic markers (mannitol, polyethylene glycols (PEGS) 900 and 4000) indicated that the paracellular permeability of the co-culture model was greater than that of the CaCo-2 model. At pH 7.4, no difference in the transport of a model lipophilic drug, dextropropoxyphene, was observed between the two models. However, at pH 4.5, when the drug was highly ionised the transport was significantly lower across the co-culture monolayers. NaTC micellar systems appeared to affect the different cell culture models in the order CaCo-2>CaCo-2-Ht29GlucH>Ht29GlucH. Following removal of the mucus layer by incubation with the mucolytic agent, N-acetyl-l-cysteine, the absorption enhancing potential of NaTC micellar systems was increased in the co-culture model.
Assuntos
Mucinas/metabolismo , Ácido Taurocólico , Absorção , Transporte Biológico , Células CACO-2 , Técnicas de Cocultura , Dextropropoxifeno/metabolismo , Impedância Elétrica , Células Caliciformes/citologia , Humanos , Micelas , Microscopia Eletrônica , Permeabilidade , Ácido Taurocólico/químicaRESUMO
The aim of this study was to compare the permeation enhancing potential and toxicity of simple bile salt and bile salt:fatty acid mixed micellar systems using the CaCo-2 cell culture model. The effects of micellar systems of sodium cholate, (NaC), and sodium taurocholate, (NaTC), on the permeability of the hydrophilic markers, mannitol (182) and polyethylene glycols (PEGS) 900 and 4000, were assessed. Simple micelle systems of the unconjugated bile salt, NaC, caused greater enhancement of the hydrophilic markers than the conjugated bile salt, NaTC. In the case of NaC systems the enhancement was coincident with excess membrane disruption and toxicity as indicated by altered TEERs, TEMs, MTT values, and, the lack of recovery following removal of the enhancer. In contrast, the NaTC systems were less toxic, and, in the simple micelle form the likely mechanism of enhancement of the hydrophilic markers is via a transient effect on the tight junctions. Formation of mixed micellar systems with linoleic acid (LA) accentuated the toxic effects of NaC. In comparison, NaTC:LA mixed micelles showed superior permeability enhancement versus simple micelles without increasing membrane toxicity. The mechanism of enhancement of NaTC:LA appears more complex and involves a possible combination effect on both the paracellular and transcellular routes.